Bernardo Gutierrez ,Darlan da Silva Candido,Sumali Bajaj,Abril Paulina Rodriguez Maldonado,Fabiola Garces Ayala,María de la Luz Torre Rodriguez,Adnan Araiza Rodriguez,Claudia Wong Arámbula,Ernesto Ramírez González,Irma López Martínez,José Alberto Díaz-Quiñónez,Mauricio Vázquez Pichardo,Sarah C. Hill, [ … ],Marina Escalera-Zamudio [ view all ]

Published: Plos Neglected Tropical Diseases, September 6, 2023

https://doi.org/10.1371/journal.pntd.0011169

Results indicate that CHIKV, DENV-1 and DENV-2 in Mexico share evolutionary and epidemiological trajectories. The southwest region of the country was determined to be the most likely location for viral introductions from abroad, with a subsequent spread into the Pacific coast towards the north of Mexico. Virus diffusion patterns observed across the country are likely driven by multiple factors, including mobility linked to human migration from Central towards North America. Considering Mexico’s geographic positioning displaying a high human mobility across borders, our results prompt the need to better understand the role of anthropogenic factors in the transmission dynamics of Aedes-borne arboviruses, particularly linked to land-based human migration.

Louis Lambrechts, Robert C. Reiner et.al.

Plos Neglected Tropical Diseases Sept 2023

https://doi.org/10.1371/journal.pntd.0011593

This study in Iquitos, Peru, showed that dengue patients with mild disease were most infectious to Aedes aegypti mosquitoes 2 d after the onset of symptoms and that these mosquitoes were able to transmit their infection 7 – 16 d after blood feeding.  This empirical study provided a timeline for when secondary dengue cases could be expected following the onset of symptoms in an imported dengue case, thereby providing a timeline for preventive control operations.    

September 29, 2023

From New York Times

Climate change and the rapid evolution of the insect have helped drive up malaria deaths and brought dengue and other mosquito-borne viruses to places that never had to worry about them.

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From LA Times

September 21, 2023

When you think “so L.A.,” Erewhon smoothies, Barbie-pink sunsets and baristas with IMDB credits might come to mind. Now you can add mosquitoes to the list.

Read more here

From Patch

September 16, 2023

As the blood-sucking ankle-biters take bite out of the Golden State, human West Nile Virus cases are spiking.

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September 7. 2023

From the County of Los Angeles Public Health

First death of 2023 reinforces need for all residents to take precautions against mosquitoes

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:ZahidMH, VanWykH, MorrisonAC, ColomaJ, LeeGO, CevallosV, etal.(2023)

https://doi.org/10.1371/journal.pntd.0010831

Author summary: Half of the world’s population is now at risk of dengue infection, which transmits to humans mostly through the bite of an infected female Aedes aegypti mosquito. Disease transmission models have played an important role in understanding the dynamics of dengue transmission and helping to develop control measures. The mosquito biting rate is one of the central parameters used in these models. Mosquito biting rates used in existing works are taken from a variety of studies, each with its strengths and limitations. To understand how existing study designs are used to estimate biting rate and how these estimates may vary over time, space, and environmental factors, we perform a systematic review of biting rate studies. We identify three study designs (human landing catch, marked-release-recapture, and histological) that play an important role in estimating per mosquito biting rates and capturing variability across a number of environmental factors. In particular, human landing catch studies can capture the variability of biting rates and marked-released-recapture studies along with histological studies can quantify the multiple feeding that occurs between ovipositions. Transmission modeling studies should be more informed by the biology of mosquito behavior. By understanding the biology of blood-feeding and context-specific factors, we can arrive at more informed per mosquito biting rate estimates for site-specific transmission model analysis.

[Submitted by the Vector and Vector-Borne Disease Committee]

August 30, 2023

From Los Angeles Times

West Nile virus infections are on the rise this year in California after a particularly wet winter led to more mosquito reproduction, according to health experts.

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August 24, 2023

From CNN

The United States has seen a flurry of West Nile virus deaths reported in the last few days, including most recently in Illinois, Nebraska and Colorado.

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From Entomological Society of America

August 23, 2023

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From the Orange County Register

August 11, 2023

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From KVPR

August 7, 2023

One mosquito abatement district in Tulare County has reportedly purchased its first-ever drone, amphibious vehicle and airboat.

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Los Angeles County, California, 2022

August 1, 2023

Recently, locally acquired cases of malaria in Florida and Texas have received national media attention. MVCAC has developed the below statement for member agencies to use when responding to questions regarding these detections and the risk of locally acquired cases in California. MVCDs are encouraged to tailor this statement with information specific to their district.

Despite reports of recent malaria cases in Florida and Texas, local transmission of malaria in the U.S. is very rare. Most malaria cases are acquired when people travel outside of the U.S. where malaria transmission occurs. Anopheles mosquitoes that can spread malaria are present in California, but the parasites that cause malaria are not currently found in these mosquitoes in California. The last cases of local transmission of malaria in California were reported in 1990. About 100 cases of malaria are reported each year in California from people who were infected while traveling in other countries. Since malaria is a reportable disease, all diagnosed imported cases are tracked by the state and local public health departments. The patient’s history and potential for exposure to local malaria vectors are evaluated and if need be, actions are made to prevent possible transmission within the local community.

Mosquito and vector control agencies in California monitor many species of mosquitoes including those that carry West Nile Virus, invasive mosquitoes, and those that have the ability to carry malaria. Mosquito and vector control agencies do this to protect public health and quickly respond when mosquito-borne diseases threaten residents.

Residents are encouraged to wear EPA-registered insect repellent and dump and drain all standing water in and around their homes to prevent mosquito bites. To learn more about mosquito prevention please visit mvcac.org. To learn more about malaria please visit the CDC and the California Department of Public Health.

From Hoodline

August 1, 2023

In response to the discovery of West Nile virus-positive mosquitoes in San Jose and Milpitas, the Santa Clara County Vector Control District has initiated truck-mounted insecticide treatments to control and kill adult mosquitoes in the affected areas. 

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June 2023

For vector control districts that wish to use pyriproxyfen in WOTUS, an updated Notice of Intent form and Pesticide Application Plan needs to be submitted to the State Water Board. Examples of completed documents can be found on the Water Board NPDES Vector Control Permit website. Due to web accessibility requirements, the State Water Board is no longer allowed to post 3^rd party documents unless they are ADA-compliant. Therefore, the Water Board requests applicants post documents on their webpage and provide a link which will then be used to post on the State Water Board website for 30-day public comment as required per the permit.

Email Gurgagn Chand, Gurgagn.Chand@waterboards.ca.gov, your website link for the document. After the application link is posted for 30-day public comment, Water Board staff will notify you of any items that need to be addressed within the amended application package as well as any public comments received. If everything checks out, generally an amended Notice of Applicability approving the revisions will be issued by the Deputy Director of Water Quality within 1-2 weeks. 

Email MVCAC Regulatory Affairs Committee Chair (Erika Castillo, erika@mosquitoes.org) if you have any additional questions.

Click here to read

Summary:  CDC is collaborating with two state health departments on an investigation of six locally acquired cases of Plasmodium vivax malaria in Sarasota County, FL and one case in Cameron County, TX. There is no evidence to suggest that the cases in the two states are related. All patients were promptly treated at area hospitals and are recovering.

Most malaria cases diagnosed in the United States are imported, usually by persons who travel to countries where malaria is endemic. However, locally acquired mosquito-transmitted malaria cases can occur, as Anopheles mosquito vectors exist throughout the United States. In 2003, for example, there were 8 cases of locally acquired P. vivax malaria identified in Palm Beach County, FL.

Note: These vivax cases were travel related, but the source of the initial infection was not indicated. Possibilities include tourists visiting malaria endemic countries or immigrants with active parasitemia or relapsed chronic liver infections. The last outbreak of locally transmitted malaria in California occurred among farm workers in San Diego County during 1988 with Anopheles hermsi as the reputed vector

[https://www.cdc.gov/mmwr/preview/mmwrhtml/00001559.htm]. These events serve to remind us that we have vectors of travel related pathogens other than invasive Aedes.  

[Submitted by the Vector and Vector-borne Disease committee]

KK Brisco, CM Jacobsen, S Seok, X Wang, Y Lee, OS Akbari, AJ Cornel

J Med Entomol 60: 364–372, https://doi.org/10.1093/jme/tjad005

Abstract [condensed]: Our In2Care trial was performed in the coastal settlement of Miloli’i in the southwest of Big Island where both Ae. aegypti and Ae. albopictus are found. This trial from Jul – Oct 2019 fell within the traditional wet season. No significant reduction in egg or adult counts were observed following 12 wk of two In2Care trap placements per participating household. In fact, an increase in adults during the trial required the local mosquito abatement program to stop the In2Care trap trial and institute a thorough source reduction and treatment campaign. The source reduction campaign revealed that a large variety and quantity of water sources competed with the oviposition cups that we had placed, which likely lowered the chances of our oviposition cups being visited by pyriproxyfen-contaminated Aedes adults exiting the In2Care traps.

Note: This report indicates that abundant alternative oviposition sites can compromise control that focuses on oviposition behavior. 

[submitted by the Vector and VectorBorne Disease committee].  

From ABC 50 Action News

May 26, 2023

Officials are asking residents to use insect repellent with DEET, wear long sleeves outdoors and drain any standing water.

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Laroche, M. and Weeks, E.N.I.

University of Texas, Galveston, TX and University of Florida, Gainseville.

Med. Vet. Entomol. 2023: 37: 177-178. DOI: 10.1111/mve.12646

Summary [VVBD Committee]: This short but interesting editorial reviews the bacteria transmitted by arthropods and concludes that although the burden of bacterial arthropod-borne bacterial diseases remains lower than the joint burden of parasitic and viral arthropod-borne diseases, there is an undeniable need to study these neglected pathogens. Significant gaps in their ecology, transmission pathogenesis still need to be filled.

Morgan E. Gorris*, James T. Randerson, Shane R. Coffield, Kathleen K. Treseder, Charles S. Zender,

Chonggang Xu, and Carrie A. Manore

Environmental Health Perspectives 2023. Vol. 131, No 4. https://doi.org/10.1289/EHP10986

*Author email:  mgorris@lanl.gov

Summary [by Vector and Vector-borne Disease committee]: Using human case report data from 2005 to 2019 and seasonally averaged climate variables, the authors developed a predictive module to estimate mean annual WNV incidence. They found that regions with dry and cold winters and wet and mild summers have higher WNV incidence rates. Among the climate variables considered, winter precipitation, fall precipitation, and winter temperature were the three most important predictive variables. The authors believe this model may be a tool to predict the future spatial extent of WNV risk related to climate change. They acknowledged that subregional patterns of WNV are likely to be strongly influenced by a series of environmental variables such as land use, vegetation coverage, and hydrology. Dry agriculture landscapes that require significant irrigation also will influence patterns of WNV incidence.

From ABC7
May 3, 2023

For the first time, drone technology is taking off to combat mosquitos in the South Bay after an unprecedented rainy winter.

Mosquito season just started and this week the Santa Clara Vector Control District will begin using drones to reduce the mosquito population.

Nayer Zahiri, the county’s Vector Control District manager, said other districts in the state are using it.

“As you see a lot of standing water, a lot of waters around and we want to make sure we are able to control the stages we can control before they become adults,” Zahiri said.

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From Times of San Diego
April 20, 2023

San Diego County will conduct its first larvicide drop of the year on up to 51 local waterways as part of a campaign to combat diseases spread by mosquitoes such as West Nile virus, it was announced Wednesday.

Aerial larvicide drops are carried out once a month between April and October each year, covering around 1,300 acres of mosquito breeding areas.

The routine helicopter drops will be conducted next Wednesday, and Thursday if necessary, according to a news release from the county.

County officials say the larvicide does not hurt people or pets.

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Posted by Vector and Vector-borne Disease Committee
April 19, 2023

Leslie Foss*, Tina Feiszli, Vicki L. Kramer, William K. Reisen, Kerry Padgett.

*Leslie.Foss@cdph.ca.gov

PLoS ONE April 6, 2023 https://doi.org/10.1371/journal.pone.0284039

Abstract [condensed]

Since 2003, the California West Nile virus (WNV) dead bird surveillance program (DBSP) has monitored publicly reported dead birds for WNV surveillance and response. We examined DBSP data from the early epidemic years (2004–2006) with recent endemic years (2018–2020) to characterize changes in program operations, patterns of dead bird reports, and WNV prevalence among dead birds and their utility as early indicators of WNV activity. In recent years fewer agencies collected dead birds for testing, but updated protocols enhanced the efficiency of the program. The number of dead bird reports was approximately ten times lower during 2018–2020 compared to 2004–2006; reports from the Central Valley and parts of Southern California decreased the most. Dead corvid, sparrow, and quail reports decreased the most compared to other bird species reports. In the early years, WNV positive dead birds were the most frequent first indicators of WNV activity; in contrast, during 2018–2020 mosquitoes were the most frequent first indicators. Evidence for WNV impacts on avian populations and susceptibility are also discussed.

Note: Despite declines in the number of birds reported by the public, dead bird surveillance remains important to better understand changes in WNV ecology and adds critical data to a comprehensive environmental surveillance program.

From ABC 7
April 12, 2023

ORANGE COUNTY (KABC) — Southern California is still a couple months away from mosquito season, but this season could potentially be one of the worst because of all the rain to start the year.

However, the Orange County Mosquito and Vector Control District is being proactive.

Heather Hyland, director of communications for OC Vector, said spots that didn’t have standing water before may have some now.

“There’s areas due to the rain that are filling up that are producing more egg laying sites for mosquitos per usual,” Hyland said.

She said they’re seeing more mosquitoes in traps laid out to monitor their population.

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