Submitted by the MVCAC VVBD Committee

Vaziri, A. 12 Jun 2026. San Francisco Chronicle.

Berkeley health officials are widening their response to a rare, rat-borne disease after confirming the city’s first known human cases in more than a decade. One person died and another was hospitalized after contracting leptospirosis, a bacterial disease commonly spread through the urine of infected animals. City officials said both infected people were living in a severely rat-infested RV about a mile from a northwest Berkeley encampment where the disease had previously been found in rats and dogs.

Note: Leptospirosis is endemic in most Rattus populations and MVCAC personnel trapping/handling rats should take care and where protective gloves and clothing.

Submitted by the MVCAC VVBD Committee

https://www.morningagclips.com/usda-confirms-presence-of-new-world-screwworm-in-the-united-states/

WASHINGTON — The U.S. Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) confirmed the detection of a New World screwworm (NWS) in a bovine in Zavala County, Texas. NWS is a serious pest that affects livestock, pets, wildlife, and less commonly, people and birds. NWS larvae (maggots) burrow into the flesh of living animals, causing serious damage to livestock and economic losses. The affected animal is a 3-week-old calf and larvae were identified in its umbilical area. To date, there have been no further detections.

Note: The NWS has been moving progressively north through Central America and then Mexico after bridging the Darian Gap. There was an earlier outbreak of NWS in the deer in the Florida Keys, but this was the first detection near the Mexican border. The USDA is constructing new facilities to produce sterile males for massive SIT releases.

Submitted by the MVCAC VVBD Committee

2026. Lazzari, CR, et al. J Exp Biol (2026) 229 (10): jeb251935. https://doi.org/10.1242/jeb.251935

ABSTRACT

Repellents are central to personal protection and to reducing transmission of mosquito-borne diseases. Although substantial effort has been devoted to identifying the sensory and molecular pathways underlying repellent detection, the diversity of reported modes of action has hindered the development of a unified framework. It is generally assumed that insects respond to repellents in a fixed, aversive manner. However, an unexplored possibility is how plastic the innate meaning of repellents may be. We present experiments testing whether the innate response of Aedes aegypti to DEET (the gold-standard repellent) can be shifted from aversion to attraction. First, we identified and validated an appetitive behavioural response in mosquitoes equivalent to PER conditioning in flies and bees: the biting attempt response (BAR). Next, we trained individual mosquitoes to associate DEET with a blood meal using Pavlovian conditioning. We then examined whether mosquitoes trained with blood as a positive reinforcer would display the BAR when presented with DEET alone or on host skin. Finally, we trained females to associate DEET with sugar and tested their subsequent response to DEET alone. Across all experiments, trained mosquitoes showed a reversal in the valence of DEET, shifting from innate avoidance to a learned appetitive response. These results demonstrate that experience can render DEET attractive by establishing associations with two rewarding contexts: vertebrate blood feeding and plant sugar feeding. We discuss the implications of this learned attraction for understanding repellent mechanisms and for designing strategies to improve personal protection.

Note: Interesting experiments that certainly may explain why older females may exhibit reduced avoidance. Years ago while working with Proctor and Gamble, Bruce Eldridge and I found that DEET was really the only compound that worked well to repel female snow pool Aedes. The pre-aegypti era trials never evaluated aegypti or albopictus.

Submitted by the MVCAC VVBD Committee

RM Davis and DE Biggins. 2026. VECTOR-BORNE AND ZOONOTIC DISEASES. DOI: 10.1177/15303667261451608

Abstract: Plague is a disease that poses serious threats to public and ecosystem health. Its causative bacterium, Yersinia pestis, was transported to North America around 1900, where it quickly became established in native rodent populations and spread throughout the western half of the United States by the mid-1900s. Many questions remain about plague circulation in the numerous rodent species involved, but its ecology in rabbits and other lagomorphs is even less understood. We describe a plague epizootic that appeared to involve both desert cotton-tail rabbits (Sylvilagus audubonii) and black-tailed jackrabbits (Lepus californicus). We believe this to be the first such description to involve both species of rabbits and the first description of a plague epizootic in the Mojave Desert. This epizootic also involved a human case of plague. We discuss human health ramifications of plague in rabbits and suggest a potential link between plague and the general long-term decline in rabbit populations, especially for jackrabbits.

From the San Francisco Chronicle
June 3, 2026

Google is seeking permission from federal regulators to release up to 32 million sterile mosquitoes in California — a pest control technique meant to quell the spread of an invasive mosquito species that’s been expanding to many parts of the state, including the Bay Area.

The Mountain View tech giant has requested a permit from the U.S. Environmental Protection Agency to initiate a project that would release up to 16 million mosquitoes in California in the first year of the project and another 16 million in the second year, according to a notice published May 6 in the Federal Register.

The proposal appears to be part of Google’s “Debug Project,” a group of scientists and engineers working to eliminate disease-carrying mosquitoes, according to the company’s website. Debug did not respond to questions from the Chronicle.

The application with the EPA seeks to use a bacteria called Wolbachia that makes male mosquitoes sterile. When male mosquitoes are infected with Wolbachia, they become unable to breed with wild mosquitoes that do not have the same bacteria, according to a description of the method on Debug’s website.

Using Wolbachia to sterilize male mosquitoes is one type of “sterile insect technique.” Pest control professionals have used SIT a long time with other insects, often to protect crops.

With respect to mosquitoes, SIT has traditionally used radiation to sterilize male mosquitoes before releasing them to mate with female mosquitoes to produce nonviable eggs that do not hatch. Over time, this helps lower the population of that particular species of mosquitoes. Male mosquitoes do not bite or spread disease, so the technique does not raise the risk of humans getting bit or contracting mosquito-borne diseases.

This method using Wolbachia bacteria was tested in Singapore in a two-year trial from 2022 to 2024, and reduced the mosquito population and risk of dengue infection among residents, according to a paper published in the New England Journal of Medicine in February.

Debug previously partnered with the local mosquito abatement district in Fresno County 2017 to do a pilot project using the Wolbachia method in 222 acres of residential neighborhoods. It significantly reduced the female mosquito population.

Sterile insect technique is promising, and some mosquito abatement districts in California are already using it — both the radiation and the Wolbachia methods — in small areas, like subdivisions, said Peter Bonkrude, district manager of the Marin/Sonoma Mosquito and Vector Control District. But questions remain about whether the technology is scalable and cost-efficient to do in large areas.

Google’s proposed project to release millions of sterile mosquitos may be able to help answer these questions.

Read more

Submitted by the MVCAC VVBD Committee

KA Dagg and ER Burgess IV. 2026.

Getting wild-caught mosquitoes to lay eggs in a lab is often a challenge. A team of researchers at the University of Florida has developed a simple method to get two important mosquito species to readily lay eggs. The team developed oviposition chambers with four simple items: cotton, germination/filter paper, a 1.5 milliliter (mL) centrifuge tube, and tap water. A piece of cotton, moistened with tap water, was pushed to the bottom of the tube, a small strip of germination paper was placed over the cotton, and finally a small hole was punched through the top of the tube lid to provide air exchange. (published in Dagg et al. 2025, PLOS Neglected Tropical Diseases).

Note: Getting gravid females to oviposit by confinement either in small containers [as depicted here] or by removing the wings and placing them in Petri dishes on water has been done for years. However, this paper may serve as a reminder for those seeking to establish new colonies or doing experiments where progeny are needed from individual females.

Read more

From the Los Cerritos Community News
May 20, 2026

The first West Nile virus activity of 2026 has been detected in Los Angeles County after mosquito samples collected in Pico Rivera and Long Beach tested positive for the virus, according to the Greater Los Angeles County Vector Control District.

The agency announced Wednesday that mosquito traps in both cities confirmed the presence of West Nile virus in local mosquito populations, marking the first positive mosquito samples detected this year.

Officials warned the early detections are a sign mosquito season is already underway across Southern California.

“West Nile virus is regularly detected in the environment throughout Los Angeles County, and these early detections are a reminder that mosquito season is already underway,” GLACVCD Scientific-Technical Manager Angela Caranci said in a statement.

The virus is primarily spread through bites from infected Culex mosquitoes, which are most active during dusk and dawn hours.

Health officials urged residents to begin taking precautions immediately, including removing standing water around homes and using mosquito repellent outdoors.

“Dumping standing water, reporting neglected swimming pools, and using mosquito repellent are simple but effective ways to reduce risk,” Caranci said.

There is currently no human vaccine for West Nile virus.

Read more

Alameda County Mosquito Abatement District was invited to conduct a long form interview about West Nile virus, after the first detection of WNV in a bird in Alameda County. 

https://www.ktvu.com/video/fmc-u1b0r8j78kuto6me?fbclid=IwY2xjawRpsJdleHRuA2FlbQIxMQBzcnRjBmFwcF9pZBAyMjIwMzkxNzg4MjAwODkyAAEeKoolLK5cMHE6f11B5ZX_HxTrF3rP-z-kY24L36mDi12F67-MiQgLAlUQe8E_aem_30q4bWGXzvL1Ti1aq8S-WQ 

Submitted by the MVCAC VVBD Committee

Vaughan AM, Park C, Ngo VP, Contreras ZA, Lee J, Danza P, et al. 2026. Investigation of and Response to Autochthonous Dengue, Los Angeles County, California, USA, August–November 2024. Emerg Infect Dis. 2026;32(5):720-727.

Abstract

Dengue is not endemic in the continental United States; most cases occur in returning travelers. During August–November 2024, a total of 14 locally acquired cases of dengue were identified in Los Angeles County, California, USA. Epidemiologic evidence indicates that locally acquired cases occurred in several neighborhoods, suggesting short transmission chains after introductions from returning travelers. In one neighborhood, evidence supported ongoing transmission for up to 7 weeks. Median patient age was 54 (range 5–79) years; 8 (57%) patients were female and 6 (43%) male, and 6 (43%) required hospitalization. Delays in healthcare seeking and diagnoses were noted; median time from symptom onset to specimen collection for dengue testing was 9 (range 2–34) days. Local dengue transmission in Los Angeles County highlights the emerging threat of mosquitoborne disease transmission in nonendemic areas and the need for rapid and coordinated public health and vector control responses to interrupt transmission.

Read more

A new article from the San Francisco Chronicle is sounding the alarm: thanks to a mild winter, warm stretches in February and March, and a rainy spring, mosquito breeding is ramping up ahead of schedule across the Bay Area. This means heightened risk for West Nile virus — California’s primary mosquito-borne disease — which can cause mild flu-like symptoms in most people but lead to severe neurological issues or even death in rare cases.

Of particular concern is the continued spread of the invasive Aedes aegypti (yellow fever mosquito). Once largely pushed out of California, this aggressive “ankle-biter” has re-established itself in Southern California over the past 15 years and is now confirmed in 28 counties, including Contra Costa, Santa Clara, Alameda, and Solano in the Bay Area. It can transmit dengue, Zika, chikungunya, and yellow fever — diseases we work hard to keep out of our communities.

At the Mosquito and Vector Control Association of California (MVCAC), our 60+ member districts are already intensifying surveillance, larval control, and public outreach to stay ahead of the season. From trapping and testing to targeted treatments, our professionals are on the front lines protecting public health.

What YOU can do right now to help:

• Tip and Toss — Empty, cover, or discard any containers holding standing water (even bottle caps and plant saucers!)
• Use EPA-approved repellents and wear long sleeves/pants at dawn and dusk
• Report dead birds to your local vector control district — they’re key sentinels for West Nile virus

Read the full story here: https://www.sfchronicle.com/health/article/mosquito-yellow-fever-west-nile-22235476.php

California’s vector control districts are stronger when communities partner with us. Let’s keep our neighborhoods mosquito-free and disease-free this season!

Submitted by the MVCAC VVBD Committee

Dunford JC, et al. Journal of Medical Entomology, Volume 63, Issue 1, February 2026, tjag019, https://doi.org/10.1093/jme/tjag019

Abstract
Oropouche virus (OROV) has expanded its distribution in the Neotropics and Caribbean (2023–2025). Over 100 reported travel cases of OROV have been reported in travelers returning to Florida alone. The primary insect vector, Culicoides paraensis (Goeldi), is present in the United States and it is essential to update our knowledge of its distribution to better understand the risk of OROV encroaching into continental United States and US Caribbean territories of Puerto Rico and the US Virgin Islands. An updated distribution map for C. paraensis is presented based on newly compiled distribution records from recent field collections, data mined from archived museum specimens, online databases, and published literature. The known US range of C. paraensis is expanded to include 219 counties across 24 states and Washington DC, and new state records for Arkansas, Michigan, and New Jersey, and a previously unreported museum record for the District of Columbia are reported. Bionomics, surveillance and control, taxonomy and systematics, and medical importance is also provided for C. paraensis in this review.

Note: At present this is the only known vector of Oropuche Virus in NA.

Submitted by the MVCAC VVBD Committee

Advancing knowledge on Culicoides biting midges (Diptera: Ceratopogonidae), vectors of medical, and veterinary importance Free McGregor BL, McDermott EG. 2026. Journal of Medical Entomology, Volume 63, Issue 2, April 2026, tjag044, https://doi.org/10.1093/jme/tjag044

Abstract
Culicoides biting midges (Diptera: Ceratopogonidae) remain some of the most understudied vector species, despite their important role in the global transmission of viral and parasitic disease agents of animals and humans. Over the last decade, advances in molecular taxonomy combined with outbreaks of pathogens like bluetongue virus (BTV), epizootic hemorrhagic disease virus (EHDV), and Oropouche virus have driven a burst of new research activity on this genus. In this Special Collection, we highlight some of the exciting work being done on Culicoides in the United States and Europe. Topics in the collection span from diversity surveys on understudied species and regions to behavior and physiology to vector competence. Two timely review articles (on EHDV in the United States and BTV in Europe) are also included. We hope this Special Collection will spur new interest in Culicoides as we continue to advance our knowledge of these important vectors.

Note: This is the Introduction to this Special Collection to appear in the JME.

Submitted by the MVCAC VVBD Committee

Persinger RD, Buczek J, Quilici M, Kuchinsky SC, McLaughlin C, Sewall K, et al. (2026) Susceptibility of wild and domestic songbirds to Usutu virus. PLoS Negl Trop Dis 20(4): e0014213. https://doi.org/10.1371/ journal.pntd.0014213

Abstract: Usutu virus (USUV) is an emerging mosquito-borne orthoflavivirus that can cause neuroinvasive disease in humans and wild birds. USUV clusters phylogenetically within the Japanese encephalitis virus serocomplex, sharing antigenic and ecological similarity with West Nile virus (WNV). USUV is maintained in an enzootic cycle primarily involving passerine birds and Culex spp. mosquitoes. USUV was first isolated in South Africa in 1959 and has since spread throughout Africa and Europe, causing mortality and disease in several wild bird populations, specifically the Eurasian blackbird (Turdus merula). To understand transmission and pathogenesis of USUV in birds, we sought to develop passerine bird models of infection using wildcaught house finches (Haemorhous mexicanus), wild-caught American robins (Turdus migratorius), domestic canaries (Serinus canaria domestica), and captive-bred zebra finches (Taeniopygia guttata). Birds were inoculated with one or two isolates of USUV and viremia was measured. House finches, American robins, and canaries were susceptible to USUV, with 100% of inoculated birds developing viremia. These avian species reach viremias that have the potential to infect Cx. quinquefasciatus mosquitoes. Clinical disease and histopathological evidence of disease were severe in American robins and moderate to severe in canaries, with limited disease in house finches. However, zebra finches inoculated with one isolate of USUV did not develop detectable viremia. These findings provide additional tools for studying USUV enzootic transmission and pathogenesis in passerine birds.

Note: Although USUV has yet to be detected in the New World, it’s ecology and epidemiology are similar to WNV, making introduction a possibility. From this paper, it would seem that we have all the necessary components in place to support enzootic transmission should this virus be introduced.

Submitted by the MVCAC VVBD Committee

Association of avian biodiversity and West Nile Virus circulation in Culex mosquitoes in Emilia Romagna, Italy. Wang, Y., et al. 2026. PLoS Negl Trop Dis 20(3): e0014076. https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0014076

Abstract.

Background

West Nile Virus (WNV) is a zoonotic arbovirus maintained in a transmission cycle between Culex mosquitoes and birds, occasionally spilling over into humans. The impact of avian biodiversity on WNV circulation remains debated, with studies reporting both negative and positive correlations (dilution and amplification effects respectively) across different settings. In Europe, this relationship remains largely unexplored, particularly in regions with high WNV transmission, such as Emilia-Romagna in Northern Italy.

Methods

We explored the association between avian biodiversity and WNV circulation in Culex mosquitoes in Emilia-Romagna using 11 years (2013–2023) of entomological surveillance data paired with two avian data sources. We calculated avian biodiversity indices (Shannon’s, Simpson’s, and Chao2) from observation records from the Farmland Bird Index project and applied linear regression models to assess their relationship with WNV detection frequency. Moreover, we used Bayesian spatiotemporal regression models and gridded weekly avian abundance estimates from the eBird project to analyse the associations between avian species richness indices and WNV transmission risk quantified by vector index (VI) at 68 geolocated mosquito traps across the region.

Results

We observed consistent negative associations between WNV detection frequency in the Culex population and avian biodiversity indices, supporting the dilution effect hypothesis (DEH). We found that non-passerine species richness was negatively associated with VI while passerine species richness showed a positive association after adjusting for covariates and spatial random effects. These findings suggest that passerines may amplify WNV transmission, whereas the presence of non-passerine species is associated with reductions in WNV circulation.

Note: These findings support earlier studies in California by Thiemann et al. that showed the intensity of blood feeding on highly susceptible WNV avian hosts decreased in rural areas where avian and other host diversity was greatest.

Submitted by the MVCAC VVBD Committee

A Chakravarti, et al. 2026. Journal of Medical Entomology, Volume 63, Issue 2, April 2026, tjag006, https://doi.org/10.1093/jme/tjag006

Abstract

The rapid spread of West Nile virus (WNV) is a growing concern. With no vaccines or specific medications available, prevention through mosquito control is the only solution to curb the spread. Mosquito traps, used to detect viral presence in mosquito populations, are essential tools for WNV surveillance. But how do we decide where to place a mosquito trap? And what makes a good trap location, anyway? We present a robust statistical approach to determine a mosquito trap’s ability to predict human WNV cases in the Chicago metropolitan area and its suburbs. We then use this value to detect the landscape, demographic, and socioeconomic factors associated with a mosquito trap’s predictive ability. This approach enables resource-limited mosquito control programs to identify better trap locations while reducing trap numbers to increase trap-based surveillance efficiency. The approach can also be applied to a wide range of different environmental surveillance programs.

Note: This approach provides a statistical method of selecting ‘best estimate’ trapping sites, but would provide upward bias for area wide long term monitoring data.

Submitted by the MVCAC VVBD Committee

Zuo et al., Sci. Adv. 12, eadz7063 (2026) March.

Abstract. Mosquito-borne diseases cause several hundred thousand deaths worldwide every year. Deciphering mosquito host- seeking behavior is essential to prevent disease transmission through mosquito capture and surveillance. Despite recent substantial progress, we still lack a comprehensive quantitative understanding of how visual and other sensory cues guide mosquitoes to their targets. Here, we combined three-dimensional infrared tracking of Aedes aegypti mosquitoes with Bayesian dynamical systems inference to learn a quantitative biophysical model of mosquito host-seeking behavior. Trained on more than 20 million data points, each corresponding to an instantaneous position and velocity in mosquito free flight trajectories recorded in the presence of visual and carbon dioxide cues, the model accurately predicts how mosquitoes respond to human targets. Our results provide a quantitative foundation for optimizing mosquito capture and control strategies, a key step toward mitigating the impact of mosquito-borne diseases.

Submitted by the MVCAC VVBD Committee

Vertical transmission in field-caught mosquitoes identifies a mechanism for the establishment of Usutu virus in a temperate country. Schilling, M., Lawson, B., Spiro, S. et al. Sci Rep 15, 25252 (2025). https://doi.org/10.1038/s41598-025-09335-x

Abstract. Usutu virus (USUV) is an emerging zoonotic flavivirus in Europe and the first zoonotic mosquito-borne virus to be confirmed in animal hosts in the United Kingdom (UK). Repeated detection of USUV in the years following its initial detection in 2020 indicated that the virus is overwintering in the UK and should now be considered endemic within southeast England. Surveillance of avian hosts and mosquito vectors has been insufficient to elucidate the mechanism by which USUV has persisted through temperate winters. Through enhanced targeted vector surveillance at the index site between 2021 and 2024 inclusive, we detected USUV RNA in host-seeking adult female Culex pipiens s.l. as well as in adults reared from field-caught larvae. This is, to our knowledge, the first description of vertical transmission of USUV in an arthropod vector that should consequently be considered a viable mechanism for the persistence of USUV in temperate areas.

Note: USUV has much the same transmission cycles as WNV which was introduced into the USA, possibly by infected mosquitoes. Detection of vertical transmission of USUV by Cx. pipiens is important because it means diapausing females and immatures as well as reproductively active females could transport the virus from Europe.

Submitted by the MVCAC VVBD Committee

Lim, JT, et al. 2026. Dengue Suppression by Male Wolbachia-Infected Mosquitoes. New England Journal of Medicine 11 Feb 2026. DOI: 10.1056/NEJMoa2503304

Abstract.

BACKGROUND Wild-type female Aedes aegypti mosquitoes that mate with male A. aegypti mosquitoes that have been infected with the wAlbB strain of Wolbachia pipientis bacteria produce nonviable offspring owing to cytoplasmic incompatibility. Repeated releases of Wolbachia-infected males can potentially suppress wild-type mosquito populations and reduce the risk of dengue virus infection. METHODS We conducted a trial involving the release of male A. aegypti mosquitoes infected with the wAlbB strain of wolbachia bacteria for the control of dengue in Singapore, a tropical city-state. In this cluster-randomized trial with test-negative controls, we divided 15 geographic population clusters into two groups: 8 clusters received deployments of male wolbachia-infected mosquitoes (intervention clusters) and 7 clusters received no deployments (control clusters). The primary end point was the diagnosis of symptomatic dengue virus infection of any severity caused by any serotype of the virus, as measured by the odds ratio for the distribution of wolbachia exposure among laboratory-confirmed reported dengue cases as compared with test negative controls. RESULTS A total of 393,236 residents lived in the intervention clusters, and 331,192 lived in the control clusters. Adult wild-type A. aegypti populations were suppressed across the intervention clusters. The baseline average abundance of the mosquitoes (number of adult female mosquitoes trapped divided by number of traps) was 0.18 and 0.19 in the intervention and control clusters, respectively; from 3 months after the initiation of the intervention until the end of the 24-month trial period, the average abundance was 0.041 and 0.277, respectively. In the intention-to-treat analysis at 6 months or more, the percentage of residents in the intervention clusters who were dengue-positive was lower than that in the control clusters (354 of 5722 tests [6%] vs. 1519 of 7080 tests [21%]). The protective efficacy of the intervention, calculated as (1 − odds ratio) × 100, ranged from 71 to 72% with 3 to 12 months or more of wolbachia mosquito exposure, as represented by odds ratios of 0.28 to 0.29. CONCLUSIONS Release of sterile wolbachia-infected male A. aegypti mosquitoes reduced vector populations and the risk of dengue infection in Singapore.

Note: This trial indicated that dengue case reduction required suppression to very female low counts per gravidtrap. They used a release density of 6 males per human that were reared in Singapore and then irradiated to ensure any contaminant females were sterilized.

Submitted by the MVCAC VVBD Committee

Phuklia W, Padith K, Phommasone K, Chansamouth V, Mayxay M, Vongphachanh S, et al. (2026) Targeting surface cell antigen 2 increases sensitivity of Rickettsia typhi detection. PLoS Negl Trop Dis 20(2): e0014004. https://doi.org/10.1371/journal. pntd.0014004

Background: Murine typhus is a flea-borne disease caused by Rickettsia typhi that typically presents as an acute febrile illness. The diagnosis is often missed, leading to delays in appropriate treatment. A qPCR targeting a single gene (ompB) for R. typhi is widely used for diagnosis; however, it has low sensitivity for detecting bacterial DNA in patients’ blood. We aimed to increase sensitivity of detection of R. typhi using qPCR by targeting a gene containing repetitive sequences, sca2 (surface cell antigen 2).

Methodology: We compared diagnostic accuracy with the standard assay targeting single sequence ompB (outer membrane protein B). Specificity, sensitivity, and bacterial load measurement of both assays were compared using stored EDTA- anticoagulated buffy coat samples from 88 patients with febrile illness at Mahosot Hospital or provincial hospitals in Laos. Among these, 55 cases were confirmed as positive or negative by first culturing Rickettsia spp. from patients’ EDTA blood, followed by assessment with IFA and ompB PCR, and buffy coat from 6 additional cases was confirmed by ompB PCR. Ten further positive cases were confirmed by IFA using paired sera, and 17 cases classified as negative for scrub typhus and murine typhus based on Rapid Diagnostic Test (RDT) results were included in the evaluation.

Results: The sca2 qPCR assay showed 59.09% sensitivity (95% CI, 38.73-76.74%) and 100% specificity (93.98-100%) for detection of R. typhi. In comparison, ompB assay demonstrated 36.36% sensitivity (95% CI, 19.73-57.05%) and 100% specificity (95% CI 93.98-100%). DNA copy number determined using the sca2 gene was approximately 2.933 log unit higher than that determined using ompB gene (median, 16,500 copies/μL; IQR, 13,045–40,000 versus median, 19.25 copies/μL; IQR, 11.11-56.62, P < 0.0001). Conclusion: This study suggests qPCR targeting sca2 increases frequency of detection of R. typhi in patients with low bacterial DNA concentrations.

Note: Study shows the difficulty of diagnosis using qPCR and the importance of collecting diagnostic samples during peak bacteremia.

Submitted by the MVCAC VVBD Committee

Wheeler, CA., et al. 2026. Journal of Medical Entomology, Volume 63, Issue 1, January 2026, tjaf183, https://doi.org/10.1093/jme/tjaf183

Abstract Surveillance is crucial for monitoring tick populations and assessing disease risk. We tested the hypothesis that dry ice-baited traps with a downward-facing sticky surface and traditional drag cloths would be equally effective in capturing ticks in Texas, Oklahoma, and Wisconsin. Experiments ran for 69 to 100 d in the spring-summer of 2023 with three, 60-m-long rows of 4 traps each, spaced 20 m apart, perpendicular to 3, 60-m-long dragging transects with traps spaced 10 m on either side. Traps captured 84.2% of a total of 25,596 ticks, and 64.3% after adjusting the data to equalize the number of person-hours expended for each sampling method. For all 3 life stages of lone star ticks, Amblyomma americanum (L.), traps almost always caught the most ticks per person-hour. For larvae and nymphs of blacklegged ticks, Ixodes scapularis (Say), and adult American dog ticks, Dermacentor variabilis (Say), trapping was either superior or similar to dragging. Correlation coefficients comparing numbers caught by trapping and dragging were generally positive for all 3 species. The magnitude of dragging needed to match the total catch in 1 trap ranged from 323 m2 for D. variabilis in Wisconsin to 511 m2 for A. americanum in Oklahoma. Trapping was also more sensitive than dragging at detecting rare tick species and experienced fewer failures to detect the presence of any ticks. These findings suggest that trapping holds promise as an alternative or supplement to current surveillance methods, pending development of a cost-effective commercial trap.

Note: Data on Ixodes are needed for comparison.

Submitted by the MVCAC VVBD Committee

Abdi AA, et al. (2026) PLoS Negl Trop Dis 20(1): e0013914. https://doi.org/10.1371/journal. pntd.0013914

Author summary: Many studies evaluate Aedes aegypti mosquito vector control approaches, but only a subset are published. One possible contributor to selective reporting, or publication bias, is the presence of a conflict of interest (COI), such as employment by the company conducting the trial or a financial conflict tied to intellectual property. We conducted a systematic review of field trials of Ae. aegypti control from 2010-2022 and examined whether studies in which authors disclose a COI report higher vector suppression than studies declaring no COI. Among 51 studies that met inclusion criteria, those with declared COI reported greater Ae. aegypti reduction of 56.7% compared to 34.5% from studies that declared no COI. We also observed that COI statements are not consistently published across journals. These findings suggest potential publication bias and underscore the need for consistent, transparent COI disclosure policies to strengthen credibility and interpretation of vector control evidence.

Note: This paper reviews published and presumably peer reviewed studies and not presentations at meetings or other events. There is a big difference between carefully reviewed evaluations and ‘infomercials’. There is a need to standardized protocols that will allow careful comparisons among different trials done at different places.

Submitted by the MVCAC VVBD Committee

Submitted by the MVCAC VVBD Committee

Probert WS, et al. 2026. Infect Dis. 2026 Jan.

https://doi.org/10.3201/eid3201.251261

Abstract

Rickettsia lanei is a newly recognized spotted fever group rickettsial species that causes severe Rocky Mountain spotted fever–like illness. We used genome sequencing, enabled by hybridization capture-based target enrichment, to establish Dermacentor occidentalis ticks as the likely source of a human infection with R. lanei in California, USA.

Submitted by the MVCAC VVBD Committee

Aguilar-Durán, JA, et L. 2025. PLoS Negl Trop Dis 19(10): e0013665.

https://doi. org/10.1371/journal.pntd.0013665

Abstract.

Background. Aedes (Stegomyia) aegypti and Ae. (Stegomyia) albopictus mosquitoes are major vectors of diseases including dengue, Zika, chikungunya, and yellow fever. The excessive use of chemical insecticides has caused resistance in mosquito populations, along with negative environmental impacts and harm to non-target organisms. In this regard, mosquito control strategies, such as passive mass trapping interventions with autocidal gravid ovitraps (AGO) offer a promising alternative. Here we report the results of a pilot study evaluating a passive mass trapping treatment using AGOs against Ae. aegypti in the city of Harlingen, Texas, USA, during the peak mosquito season. Methodology Three treatments were assessed on Aedes populations: AGO mass trapping, integrated vector management (IVM) consisting of source reduction together with larvicides and adulticides, and AGO + IVM. The study design included a control area with no treatments. Four neighborhoods were selected to evaluate the impact of treatments on Ae. aegypti comparing female abundance between pre-treatment (10 weeks) and post-treatment (9 weeks) periods. Results All treatments were effective in significantly reducing Ae. aegypti females. IVM treatment reduced the number of females per trap per week from 3.29 ± 0.24 to 2.41 ± 0.20 (33.7% reduction), AGO from 1.58 ± 0.17 to 0.25 ± 0.05 (85.2% reduction), and AGO + IVM from 1.49 ± 0.17 to 0.53 ± 0.08 (67.78% reduction), based on Henderson’s formula. We observed a non-significant increase in the control area (no treatment provided) in the mosquito populations, increasing from 2.94 ± 0.24 in the pretreatment period to 3.25 ± 0.28 of the post treatment period.

Conclusion.
Although all treatments were followed by a reduction in mosquito populations, those that included AGO showed a greater decrease in post treatment populations than conventional control measures (IVM) alone. However, further studies with a larger number of replicates, conducted across different seasons and during peak abundance months are needed to fully assess their relative effectiveness for Ae. aegypti control. As this was a pilot study, these preliminary findings suggest that AGOs contribute to reducing Ae. aegypti populations and may serve as a complementary and useful tool in integrated vector management strategies. Nonetheless, further research is needed to verify and validate their effectiveness at larger operational scales.

Submitted by the MVCAC VVBD Committee

Rodriguez et al. 2025. bioRxiv preprint. DOI: 10.64898/2025.12.16.694562

ABSTRACT The human pathogenic orthoflavivirus St. Louis encephalitis virus (SLEV) reemerged in the western United States in 2015 after more than a decade of apparent absence and has since expanded throughout California with sustained, interannual transmission. This shift from the historically sporadic pattern of SLEV activity prior to 2003 raises the question of whether contemporary SLEV strains differ in fitness in Culex vectors compared with earlier strains. To determine whether reemerging SLEV possess augmented infectivity and transmissibility that may have facilitated reestablishment, we compared the vector competence of five genotype III SLEV strains detected in California between 2016 and 2023 with a historic genotype V strain from 2003. Laboratory colonies of the two primary California vectors, Culex (Cx.) tarsalis and Cx. quinquefasciatus, were orally exposed to bloodmeals containing 3, 5, or 6.7 log10 plaque forming units (PFU)/mL of SLEV, and infection, dissemination, and transmission were assessed 13,14, or 15 days later by quantifying SLEV RNA in individual mosquitoes. Both species exhibited strong dose-dependent responses, with minimal infection at 3 log10 PFU/mL and uniformly high infection, dissemination, and saliva positivity at 6.7 log10 PFU/mL. At 5 log10 PFU/mL, genotype III strains infected Cx. quinquefasciatus more efficiently than the historical 2003 strain, which failed to infect this species. In Cx. tarsalis, fitness differences among SLEV strains were more modest and strain-specific. These findings demonstrate that multiple genotype III SLEV strains exhibit equal or greater vector infectivity in Cx. quinquefasciatus than the 2003 genotype V strain, suggesting that enhanced fitness in this vector may contribute to the persistence and geographic spread of SLEV in California since its reemergence and underscoring the need for continued vector surveillance and targeted control efforts to reduce SLEV transmission to humans.

Note: It will be useful to examine the virulence of these recent strains in passeriform host species as the historic strains elicited low viremia levels with little mlortality.

Submitted by the MVCAC VVBD Committee

Hung, KY. 2025. Journal of Medical Entomology, 62(6): 1381–1385, https://doi.org/10.1093/jme/tjaf136

Abstract: Multiple factors play a role in determining the appropriate methods for protecting communities from public health threats, requiring collaboration and communication among entities from the national to the local level to build the capacity to adapt and respond to the changing environment. This review highlights publications from 2023 that provided value for the mosquito and vector control industry with potential to benefit those working at the local level. By focusing the discussion on emerging disease and vector threats, improving the understanding of insect ecology and behavior, and developing new control strategies and laboratory practices, the studies presented herein aim to provide new ideas for more effective vector management strategies, and thus, better public health protection.

Submitted by the MVCAC VVBD Committee

Egizi, A. et al. 2025. Zootaxa 5719: 049-072. https://doi.org/10.11646/zootaxa.5719.1.2

Abstract. All active stages of Haemaphysalis vespertina sp. nov. (Acari: Ixodidae), a tick previously identified as H. leporispalustris Packard, 1869, are described from specimens collected on the vegetation and from leporids in California and Oregon. The adults of H. leporispalustris Packard, 1969 are redescribed based on type material. Adults of the two species can be distinguished by their overall size, the dorsal shape of palpal segment II, the number and shape of dorsal and ventral setae on palpal segment II, the number of spurs on coxae II, the length of setae on scutum, legs and coxae, and the pattern of EGIZI ET AL.50 · Zootaxa 5719 (1) © 2025 Magnolia Press scutal punctations. Phylogenetic analyses support H. vespertina as a distinct taxonomic lineage. Additional unresolved lineages within H. leporispalustris s.l. were identified, suggesting a need for further taxonomic study of leporid-associated Haemaphysalis ticks in North America.

Submitted by the MVCAC VVBD Committee

Lund et al. 2025. PLoS Negl Trop Dis 19(4): e0013036. https://doi.org/10.1371/journal.pntd.0013036 Abstract. Chagas disease is caused by infection with the protozoan parasite Trypanosoma cruzi, which is carried in the guts of triatomine insects. Transmission typically occurs when infective trypomastigotes in triatomine feces encounter mucous membranes or bite wounds, though it is also possible by food-borne, transplant- and transfusion-mediated, and congenital routes. Most transmission occurs in rural and peri-urban parts of continental Latin America where triatomines often inhabit human dwellings. Triatomines infected with T. cruzi are also present across the southern United States, yet relatively few locally acquired infections have been documented. Rather, most reported cases have plausible exposure in Latin America. In California, the widespread distribution of T. cruzi-infected triatomines suggests a potential risk of local transmission. Here, we summarize triatomine submissions and human case reports made to the California Department of Public Health between 2013 and 2023. Of 226 triatomines tested, 63 (28%) were positive for T. cruzi via PCR; none were linked to any of the 40 human T. cruzi cases reported in the same period. Human cases were assessed for likelihood of local transmission. Country of birth, travel history, and location of primary residence suggested non-local transmission for 31 (78%) cases. Local transmission could not be ruled out for the remaining nine (22%) cases. Information on country of birth and travel history were missing from these case reports and prevented full assessment of local transmission criteria, though most of these patients resided within 400 meters of potential triatomine habitat. Despite the presence of triatomines, T. cruzi, and human cases in California, statewide data indicates the risk for locally acquired Chagas disease is low.

Submitted by the MVCAC VVBD Committee

Wang L, et al. VIRULENCE. 2025, VOL. 16, NO. 1, https://doi.org/10.1080/21505594.2025.2580162 

ABSTRACT. Recent increases in cases of western equine encephalitis (WEE) in South America have raised significant concerns about the virus’s potential to cause an endemic disease due to its adaptation to mosquito vectors. Currently, there are no effective vaccines or treatments for WEEV, despite ongoing research into various biochemical products in animal models. The virus presents different pathological effects depending on the host. In humans, WEEV infection leads to central nervous system damage, resulting in encephalitis and severe neurological sequelae, which underscores theneed for further research into its pathogenic mechanisms. To enhance understanding of WEEV and address potential threats, this review focuses on the virus’s natural transmission cycle, the development of biochemical products for combating WEEV infection, and new diagnosis methods. It also highlights research on mechanisms in animal models, offering potential strategies for defending against WEEV.

Note: This paper did not review well the current risk assessment model and response in California which was created initially for WEEV and SLEV.

Submitted by the MVCAC VVBD Committee

Scroggs SL, et al. Sci Rep 15, 27368 (2025). https://doi.org/10.1038/s41598-025-11337-8.

Abstract:

Oropouche virus (OROV) is a vector-borne zoonotic virus that causes febrile illness in humans. Biting midges of the Culicoides genus are the primary vectors during human outbreaks. The 2022–2024 OROV outbreak has seen an increase in incidence, geographic expansion, and the emergence of previously undocumented symptoms. To better understand the basis of increased disease incidence, infection of the outbreak virus (OROV²⁴⁰⁰²³) was compared to a historical virus strain (rOROVBeAn19991) in Culicoides sonorensis, a midge species that has demonstrated historical competence. Higher levels of infection, dissemination, and transmission potential were observed in C. sonorensis infected with the outbreak strain compared to the historical strain, although infectious titers did not differ between the two viruses. OROV²⁴⁰⁰²³ was also detected in saliva at earlier time points than rOROVBeAn19991, indicating a shorter extrinsic incubation period of < 5 days compared to 7–14 days for rOROVBeAn19991. Taken together, our results demonstrate increased transmission potential of the outbreak strain in C. sonorensis midges, raising concern about the risk of spread within the United States following potential introduction. However, further studies are needed to evaluate the current strain in Culicoides species occurring within its outbreak range, including Culicoides paraensis, the confirmed South American vector of OROV.

Note: Culicoides sonorensis is found throughout California were it is the primary vector of blue tongue virus of cattle and sheep.

Submitted by the MVCAC VVBD Committee

Submitted by the MVCAC VVBD Committee

Hughes HR, et al. 2023. Journal of Medical Entomology, 60(6), 2023, 1230–1241 https://doi.org/10.1093/jme/tjad058

Abstract:

Cache Valley virus (CVV) is a mosquito-borne virus in the genus Orthobunyavirus (Bunyavirales: Peribunyaviridae) that has been identified as a teratogen in ruminants causing fetal death and severe malformations during epizootics in the U.S. CVV has recently emerged as a viral pathogen causing severe disease in humans. Despite its emergence as a public health and agricultural concern, CVV has yet to be significantly studied by the scien- tific community. Limited information exists on CVV’s geographic distribution, ecological cycle, seroprevalence in humans and animals, and spectrum of disease, including its potential as a human teratogen. Here, we present what is known of CVV’s virology, ecology, and clinical disease in ruminants and humans. We discuss the current diagnostic techniques available and highlight gaps in our current knowledge and considerations for future research.

Note: Serosurveys of rabbits and sheep in California failed to detect antibodies against CVV, although previous infection with related Lokern and 5 other Bunyaviruses were detected frequently. CVV is transmitted by Culiseta inornata in the NW USA as is Jamestown Canyon virus which has caused outbreaks in sheep. The current arbovirus testing program using RT-PCR will not detect any of these Bunyaviruses.

Submitted by the MVCAC VVBD Committee

Dean et al. N Engl J Med 2025;393:1387-98. DOI: 10.1056/NEJMoa2501069

ABSTRACT:

BACKGROUND Targeted indoor residual spraying focuses insecticide applications on common resting surfaces of Aedes aegypti mosquitoes (an arboviral disease vector) in houses, such as exposed lower sections of walls and under furniture.

METHODS We conducted a two-group, parallel, unblinded, cluster-randomized trial in Merida, Mexico, to quantify the efficacy of targeted indoor residual spraying for preventing Aedes-borne diseases (chikungunya, dengue, or Zika). Children 2 to 15 years of age were enrolled from households in 50 clusters of five-by-five city blocks. Households in 25 clusters received an annual application of targeted indoor residual spraying (intervention) before each season of Aedes-borne disease (July through December). All clusters received routine Ministry of Health vector control. The primary end point was laboratory-confirmed, symptomatic Aedes-borne disease. Community effects were assessed with the use of geolocated national surveillance data.

RESULTS A total of 4461 children were monitored for up to three seasons (2021, 2022, and 2023). The indoor density of A. aegypti mosquitoes was 59% (95% confidence interval [CI], 51 to 65) lower with the intervention than with control. A total of 422 cases of aedes-borne disease were confirmed, primarily dengue in 2023. In the per-protocol analysis of cluster centers, 91 cases occurred among 1038 participants in the intervention group and 89 cases among 1037 participants in the control group (efficacy, −12.8%; 95% CI, −60.7 to 23.0). In an intention-to-treat analysis of entire clusters, 198 cases occurred among 2239 participants in the intervention group and 199 cases among 2222 participants in the control group (efficacy, 3.9%; 95% CI, −28.1 to 26.7). Adjustment of analyses for mobility or demographic characteristics did not change results. On the basis of 150 cases in the intervention clusters and 202 in the control clusters that were geolocated, the estimated community effect of the intervention was 24.0% (95% CI, 6.0 to 38.6). Two cases of multisymptom adverse events (e.g., nausea, watery eyes, diarrhea, and vomiting) were associated with the intervention.

CONCLUSIONS Despite lower entomologic indexes with targeted indoor residual spraying than with routine vector control, the cumulative incidence of Aedes-borne diseases was not significantly lower with targeted indoor residual spraying.

Note: Indoor residual insecticide treatments are not new and were the primary approach to Anopheles control during malaria eradication efforts when all indoor surfaces of all houses were sprayed. The results herein show that mosquito population reduction >60% is necessary to prevent disease and that targeted control may be inadequate.

Submitted by the MVCAC VVBD Committee

Crawford, JE, et al. 2025.

Science 18 Sep 2025 Vol 389, Issue 6766 DOI: 10.1126/science.ads3732

Abstract. The emergence and global expansion of Aedes aegypti puts more than half of all humans at risk of arbovirus infection, but the origin of this mosquito and the impact of contemporary gene flow on arbovirus control are unclear. We sequenced 1206 genomes from 73 globally distributed locations. After evolving a preference for humans in Sahelian West Africa, the invasive subspecies Ae. aegypti aegypti (Aaa) emerged in the Americas after the Atlantic slave trade era and expanded globally. Recent back-to-Africa Aaa migration introduced insecticide resistance and anthropophily into regions with recent dengue outbreaks, raising concern that Aaa movement could increase arbovirus risk in urban Africa. These data underscore developing complexity in the fight against dengue, Zika, and chikungunya and provide a platform to further study this important mosquito vector.

Submitted by the MVCAC VVBD Committee

Birhanie, SB, et al. J. Am. Mosq. Control Assoc. 41(3): 134-142.

ABSTRACT. The In2Care Mosquito Station, which uses biological control agents to target Aedes mosquitoes, has shown promise when integrated into existing integrated vector management strategies. This study evaluated the impact of pre-season deployment of In2Care stations on Ae. aegypti populations. Two cohorts were established: 1 with 17 sites deploying stations pre-season (April–November), and another with 15 sites deploying during peak season (July–November), maintained during 2022–2024. Monthly BG-2 Sentinel trap data showed a significant reduction in Ae. aegypti abundance at pre-season In2Care sites: from 31.2 mosquitoes/trap-night in 2022 to 20.1 in 2023 and 13.2 in 2024, with a year-to-year reduction of 34–36%. Peak-season In2Care sites showed a 24–36% reduction in mosquito abundance four weeks post-deployment. Pre-season In2Care sites maintained 22–34% lower mosquito abundance than peak-season sites. These results demonstrate that early deployment of In2Care stations prior to the mosquito season significantly reduces Ae. aegypti populations and reinforces the existing integrated vector management programs.

Submitted by the MVCAC VVBD Committee

Submitted by the MVCAC VVBD Committee

Entomology Today

https://entomologytoday.org/2025/08/28/survey-entomologists-scientists-report-negative-impacts-government-actions/impacts-federal-policies-science-infographic/

In a survey of nearly 1,400 scientists released August 25, 2025, 83% said federal government policies since January 20, 2025, had caused an “extremely negative impact” or “irreparable harm” on their field of science. The survey reached members of more than a dozen scientific societies in the U.S. in ecology, evolution, and marine science, including ESA. These and other findings provide in-depth insights into how recent policy changes have affected the scientific research enterprise that supports national priorities and public welfare in the U.S.

A comprehensive survey of scientists across ecology, evolution, marine, and other life sciences points to significant disruptions to federal research programs following executive branch actions in 2025. The study, which gathered responses from nearly 1,400 members of scientific societies nationwide—including the Entomological Society of America—documents widespread impacts on research critical to American interests including food security, flood mitigation, infectious disease preparedness, and wildlife conservation.

The survey captured perspectives from scientists across all career stages and sectors, including academia, federal government, nonprofit organizations, and industry, with respondents geographically distributed throughout the United States.

Key Findings

Notable sentiments among survey respondents include:

83% of respondents said that federal policies since January 20, 2025, had “extremely negative impact” or “irreparable harm” on their field of science. Large portions of respondents reported that federal policies caused uncertainty about the future (85%) and increased stress and anxiety (79%). 71% of respondents said that US federal training programs were “very important” or “extremely important” to their development as scientists.

Respondents also shared comments about the impacts that underscored several common themes:

Research disruptions. Federal policies and workforce restructuring have caused significant interruptions to ongoing scientific work. Respondents reported disruptions to summer data collection projects and long-term monitoring programs due to direct funding cuts or uncertainty about potential cuts. These disruptions affect research supporting critical national priorities including food security, flood mitigation, infectious disease response, and wildlife management.

Restrictions on scientific communication. Scientists reported experiencing restrictions on free speech and travel, along with chilling effects that discourage open scientific discourse. Survey participants also noted censorship of scientific terminology and expressed concerns about the federal government’s ability to meet legal mandates enacted by Congress.

Loss of institutional knowledge. Reductions in force have led to decreased government efficiency and significant loss of institutional knowledge within the federal workforce, the survey found. Respondents documented delayed funding decisions, postponed collaborative research projects, and increased waste from cancellation of in-progress studies. Some participants reported breakdowns in longstanding collaborative relationships between federal agencies and state governments, academic institutions, nonprofits, and industry partners.

Training program impacts. Quantitative data from the survey highlight the critical role of federally funded programs in developing the next generation of scientists. Respondents reported severe impacts, including cancellation of undergraduate training programs, cuts to graduate admissions at universities, rescinded job offers, and reductions in merit-based fellowship programs. Scientists across career stages expressed concern about an emerging bottleneck for early-career researchers and potential long-term consequences for scientific fields.

Concerns about information integrity. Survey participants raised concerns about potential bias in or removal of information from federal sources, as well as threats to the viability of established federal programs.

Long-Term Implications

Some respondents indicated that certain harms may already be irreparable, citing disruptions to time-sensitive data collection, lost training opportunities, damaged career prospects, and harm to communities served by federal scientific programs due to the loss of institutional expertise.

The survey results provide the first systematic documentation of how recent federal policy changes have affected the scientific research enterprise that supports national priorities and public welfare.

Learn More

“Summer 2025 Survey Results”

The Impacts of U.S. Federal and State Policies on Science

Adapted from a press release originally published August 20, 2025.

Submitted by the MVCAC VVBD Committee

https://www.astmh.org

Free Webinar Translating Science: Communicating Medical Entomology to Diverse Audiences

August 15, 10:30 am Central Time

Explore how current medical entomologists from a wide array of professional sectors communicate their research and operations to the public and other stakeholders. The goal of this webinar will be to give trainees insight into how entomological science and its applications are communicated effectively to various audiences and how to start becoming an effective communicator while in the midst of graduate studies.

Panelists:

Krystal Birungi, BS Entomologist, Research and Outreach Associate, Target Malaria, London, England, United Kingdom

Molly Duman Scheel, PhD ASTMH Member, Navari Family Professor, Department of Medical and Molecular Genetics, Indiana University School of Medicine, University of Notre Dame Eck Institute for Global Health, South Bend, Indiana, United States

Sarah Michaels, PhD, MSPH ASTMH Member, Clinical Assistant Professor, Department of Tropical Medicine & Infectious Disease, Celia Scott Weatherhead School of Public Health & Tropical Medicine, Tulane University, New Orleans, Louisiana, United States

Maria Luísa Simões, PhD ASTMH Member, Associate Professor, Institute of Tropical Medicine Antwerp, Antwerp, Belgium

Ryan Smith, PhD ASTMH Member, Associate Professor, Department of Plant Pathology, Entomology and Microbiology, College of Agriculture and Life Science, Iowa State University, Ames, Iowa, United States

Chairs:

• Emre Aksoy, PhD Postdoctoral Fellow, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States
• Max McClure, MD, MS ASTMH Post-Doc Member, Infectious Diseases Fellow, University of California, San Francisco, San Francisco, California, United States
• Olayinka M. Olajiga, Bsc, MSc ASTMH Student Member, PhD Student, Celia Scott Weatherhead School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, United States
• Akilah Stewart, PhD ASTMH Post-Doc Member, Postdoctoral Fellow, Indiana University School of Medicine, South Bend, Indiana, United States
• Donald Ward, MSPH ASTMH Student Member, PhD Candidate, School of Life Sciences, Arizona State University, Tempe, Arizona, United States

This webinar will be recorded and later available to ASTMH members on GOTropMEd. Questions? Contact Buffy Finn, Membership, Subgroups and Courses Manager.

Submitted by the MVCAC VVBD Committee

Sasmita HI, Neoh K-B, Ernawan B, Indarwatmi M, Nasution IA, Fitrianto N, et al. (2025) PLoS Negl Trop Dis 19(7): e0013290. https://doi.org/10.1371/journal

Abstract. Background. Implementing the sterile insect technique (SIT) in areas with high-density target mosquito populations throughout the year is challenging. This study evaluated the effectiveness of releasing radiation-sterilized male Aedes aegypti mosquitoes, which were subjected to pre-release control measures in a highly urbanized city.

Methodology/Principal findings. A mark–release–recapture (MRR) trial was conducted to assess the performance of sterile male mosquitoes. The MRR results revealed that the life expectancy of irradiated mosquitoes was 1.2–8.8 days, and that their mean dispersal distance was 60.0–64.3 m. The estimated wild male population ranged from 1,475–2,297 male mosquitoes/ha. In the SIT trial, sterile male A. aegypti mosquitoes were released at a rate of 9,000 male mosquitoes/week/ha for 24 weeks. Pre-release control measures, including chemical fogging (Fludora Co-Max EW) and breeding site removal, were employed at the release site. A buffer zone was established by applying residual insecticide (K-Othrine PolyZone SC) and releasing sterile male mosquitoes. In the SIT trial, relative to control sites, the site with sterile male mosquitoes had considerably greater sterility in the field population (greater by 86%), resulting in reductions in the ovitrap density index, and number of wild female mosquitoes captured. In contrast, no significant reduction in ovitrap index was observed. However, despite the gradual recording of low values for egg hatching, ovitrap density index, and female capture, mosquito suppression was incomplete. The mosquito population rebounded shortly after the release of sterile male mosquitoes ended.

Conclusions/Significance. This study underscores the critical role of integrated vector management when the SIT is implemented in highly urbanized areas. It also emphasizes the importance of combining vector control interventions to ensure they are tailored to the geographic context based on logistical feasibility, available local facilities, and local knowledge of the vector.

From ASTMH

Free ACME Webinar

From Science to Solution: SIT in the Fight Against Vectors

August 6, 2025, 1 pm ET/12 pm CT/10 am PT

Join us for an engaging and timely webinar, From Science to Solution: SIT in the Fight Against Vectors, designed to raise awareness and foster informed dialogue around the Sterile Insect Technique (SIT) as a cutting-edge, science-based approach to vector control.

This session will bridge the gap between scientific research and practical implementation, showcasing how SIT has evolved from controlled laboratory experiments into real-world operational programs. Panelists will share insights into the biological principles behind SIT, present compelling case studies from successful deployments, and explore how SIT fits within broader Integrated Vector Management (IVM) strategies.

The webinar will also create a dynamic platform for collaboration and exchange among key stakeholders: researchers, public health professionals, policymakers and development partners. Together, we will examine the opportunities, challenges and policy directions critical for scaling SIT as a sustainable solution in the global fight against vector-borne diseases. Whether you’re new to SIT or looking to expand your knowledge of innovative vector control strategies, this event will equip you with the knowledge and inspiration needed to support evidence-based mosquito management.

Don’t miss this opportunity to be part of the movement turning science into impactful public health solutions.

Register Now

Panelists:

Solomon K. Birhanie, PhD

Panel Chair, ASTMH Member, Scientific Director, West Valley Mosquito and Vector Control District, United States

Presentation Title: Aedes aegypti control using SIT

Alex Arp, PhD

Research Geneticist, USDA, Knipling-Bushland U.S. Livestock Insects Research Laboratory, United States

Presentation Title: Using SIT to control screwworm

Chantel De Beer

Medical Entomologist, Joint FAO/IAEA Center of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Austria

Presentation Title: Tse-tse fly eradication using SIT

Register Now

This webinar will be recorded and later available to ASTMH members on GOTropMEd. Questions? Contact Buffy Finn, Manager, Membership.

Submitted by the MVCAC VVBD Committee

Gould,CV, et al. 2025. JAMA. doi:10.1001/jama.2025.8737 Published on line July7,2025.

IMPORTANCE: West Nile virus (WNV), a neurotropic flavivirus spread by Culex species mosquitoes, is the leading cause of mosquito-borne disease in the contiguous US. From 2014 to 2023, a mean of 1298 WNV neuroinvasive disease cases and 129 deaths were reported annually in the US.

Note: This Review focusses on the medical aspects of WNV, provides an update on the incidence of WNV in time and space within CONUS, and provides useful graphics describing pathogenesis in humans.

From The Spruce
July 1, 2025

Many homeowners and gardeners grow marigolds to deter mosquitoes and other pests. But do marigolds repel mosquitoes effectively, or are there better ways to keep mosquitoes out of your yard?

In this guide, experts share their advice on using marigolds for mosquito control, and provide all-natural tips for deterring mosquitoes without harmful toxins.

Will Marigolds Keep Mosquitoes Away?

Although marigolds are often recommended for mosquito control, they’re actually not a reliable way to keep mosquitoes at bay.

“There is no plant species that has been shown to repel mosquitoes in terms of just having the plant in your landscape—and that includes marigolds,” says entomologist Madeline Potter. “Some plants do contain chemical properties which can repel or deter pest insects, but these chemicals usually need to be physically extracted from the plant in order to significantly impact pests.”

This means that only concentrated scents like essential oils or candles will have a real repelling effect on mosquitoes. Stephen Abshier, from the Mosquito and Vector Control Association of California, agrees.

“Strong scents from plants, including marigolds, may confuse the mosquito’s sensory system and make it more difficult for them to locate people. But on their own, marigolds are unlikely to provide sufficient protection against mosquito bites,” he says.

Read more

Submitted by the MVCAC VVBD Committee

Submitted by the MVCAC VVBD Committee

2011–2019. K Yomogida, et al. 2025. Med Vet Entomol https://doi.org/10.1111/mve.12816

Abstract. In California, public health disease surveillance data for flea-borne typhus (FBT) are generated by healthcare providers and laboratories who are responsible for notifying local health jurisdictions when the disease is detected. When accounting for the associations between socioeconomic status (SES) factors (age, race and ethnicity, poverty, unemployment, housing status and land use), R. typhi reservoir host presence (e.g., rats, cats, opossums), and healthcare-seeking behaviours, it is reasonable to consider whether these factors also lead to under-reporting of FBT surveillance and distorted estimations of incidence. This study aimed to evaluate population-level associations between SES factors and FBT surveillance reporting using a Bayesian hierarchical model including a spatially autocorrelated random effect. Census tract-level covariates were sourced from the American Community Survey and Healthy Places Index (HPI). Specifying a zero-inflated Poisson distribution to FBT surveillance report counts, we estimated spatially smoothed, census tract-level estimates of FBT surveillance report rates and attributed variability in report rates to census tract characteristics. Socioeconomic advantage, as measured by the HPI, had the largest effect (IRR = 1.34 [1.07, 1.69]), corresponding to a 34% increase in FBT surveillance reporting for every point increase in HPI score for census tracts. The results herein suggest that FBT surveillance may be biased in its ascertainment of surveillance data, which may be helpful in contextualising and interpreting current trends in FBT epidemiology.

Submitted by the MVCAC VVBD Committee

Rubino, FI., et al. 2025. Journal of Medical Entomology, XX(XX), 2025, 1–10 https://doi.org/10.1093/jme/tjaf047

Abstract. In the far western United States, the bacterial agent of Lyme disease, Borrelia burgdorferi sensu lato, is primarily transmitted to humans by the nymphal stage of the western black-legged tick, Ixodes pacificus. Predicting nymphal tick abundance would benefit public health but is complicated by the tick’s complex multi-year life cycle and data limitations. To address this, we used readily available climate data, a long-term dataset from northwestern California, and time lags based on the tick’s life cycle. Our model showed that warmer early spring temperatures during non-drought conditions the year prior predicted higher nymphal tick densities, while hot, dry springs the year prior were linked to earlier peaks in their abundance. Incorporating human induced climate change projections, we predicted earlier peaks of nymphal tick activity over the next century, with the potential for an initial doubling in questing nymph numbers. This approach provides a valuable tool for public health and offers insights into the changing dynamics of Lyme disease ecology in the far-western US.

Note: It would have beneficial to also have included the effects of climate variation on lizard and mouse host abundance.

Submitted by the MVCAC VVBD Committee

Andrews, E.S. et al. Journal of Medical Entomology, Volume 62, Issue 3, May 2025, Pages 690–699, https://doi.org/10.1093/jme/tjaf032

Abstract [shortened]: To determine the influence of elevation on the seasonality and abundance of Ixodes pacificus nymphs in the Sierra Nevada foothills of California, we used a standardized flagging procedure to sample nymphs from 4,720 rocks and logs at 16 sites during 168 surveillance events and collected 1,469 I. pacificus nymphs. Nymphal abundance was similar on rock and log substrates. Tick abundance and seasonality varied by elevation, with lower elevation sites exhibiting higher nymphal abundance and earlier seasonal activity. Nymphal activity started later and persisted longer into the summer months at higher elevation sites. Nymphal abundance on rocks and logs was not predictive of adult abundance the following year, as estimated by drag sampling for adult ticks along hiking trails within the nymph sampling areas. Overall, 4.9% and 1.4% of the tested nymphs were infected with Borrelia burgdorferi s.l. and B. miyamotoi, respectively. We found no relationship between elevation and B. burgdorferi s.l. infection prevalence, although fewer nymphs were tested from higher elevation sites. These findings advanced our understanding of I. pacificus nymphal abundance and distribution and helped improve assessment of public health risks associated with tick exposure in the Sierra Nevada foothills.