Mosquito & Vector News

Dogs at higher risk of contracting heartworm disease from mosquitoes in OC, officials say

From MSN
January 20, 2022

The pesky Aedes aegypti, more commonly known as the ankle biter, is behind more than the persistently itchy welts on our legs.

Heather Hyland with the OC Mosquito and Vector Control District said Thursday that results from testing at the end of 2021, show that this species of mosquito carries heartworm, which can be fatal to our furry friends.

“Out of 260 samples, we found that four tested positive for dog heartworm detection. That’s telling us that there is dog heartworm in the community, but it’s also telling us, based on that data, that it’s low-risk right now,” Hyland said.

According to a 2019 map from the American Heartworm Society, no state is heartworm free. The darker the red, the higher the number of cases. The map shows Mississippi and Louisiana leading the country in infection rates.

The mosquitoes testing positive in Orange County came from Huntington Beach, Seal Beach, and Fullerton. The danger in Southern California is that ankle biters are rapidly breeding, and they can spread heartworm to dogs with just one bite.

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California scientists debate whether it’s menace or messiah – Times-Herald

From the California News Times
January 4, 2022

Government officials to prevent deadly illness often praise low mosquitofish as a savior of public health. However, some environmentalists call it a “pesto minnow” and a “fish destroyer.”

Almost a century after the finger-sized fish was first introduced to California in Sacramento’s lily pond, it is arguably the most ubiquitous freshwater fish in the world. However, mosquitofish are also one of the most invasive species in the world.

Almost all mosquito and carrier extermination districts in California are now deploying creatures with a variety of strategies, balancing pest control capabilities with ecological destruction of fish.

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If mosquitoes were eradicated, what would be the consequences?

From NewScientist
December 8, 2021

Jane Monroe Arcata, California, US

Mosquitoes are a major food source for many bird and bat species, and larval mosquitoes are regularly eaten by various freshwater fish and aquatic insects such as backswimmers, larval dragonflies and diving beetles.

These mosquito consumers in turn provide food and other resources for other organisms. Bats, for example, play a critical role in the health of cave ecosystems; they also consume, and help control, many agricultural pests.

The eradication of mosquitoes might please humans in the short term, but would eventually damage many ecosystems due to a cascade of negative consequences as more and more species were affected. A better plan might be to eradicate the disease-causing parasites that use mosquitoes as a vector.

“The eradication of mosquitoes might please humans in the short term, but would eventually damage many ecosystems”

Jonathan Wallace Newcastle upon Tyne, UK

This is a variant of the “what is the point of…?” question that often gets posed about species we consider to be pests.

The eradication of mosquitoes would certainly have consequences. Firstly, there is the question of how the mosquitoes would be eradicated. Spraying pesticides is the most common method, and it is inevitable that non-target species are also affected.

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Integrated Mosquito Management Protects People and Animals from Mosquitoes

From Entomology Today
December 8, 2021

“Mosquitoes are the best,” said no one ever. Adult females of most mosquito species require a blood meal from unwitting hosts to produce eggs. The hunt for blood and drive to reproduce can result in mosquitoes biting people, causing a variety of reactions ranging from nothing to itchy, red welts that leave their sufferer with an annoying reminder of the encounter. Unfortunately, sometimes these bites transmit microscopic invaders that cause terrible diseases in humans and animals such as West Nile, Zika, yellow fever, malaria, dengue, St. Louis encephalitis, eastern equine encephalitis, dog heartworm, and many more.

Mosquitoes and their associated diseases have impacted humanity throughout history. However, proof that mosquitoes could transmit pathogens and get people sick only occurred relatively recently, in the late 19th century. Until then, doctors and other public health practitioners attributed some mosquito-transmitted diseases to other causes such as miasma, or bad air.

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Orange County Vector Control Alerts Residents of Looming Mosquito Infestation

From The Epoch Times
November 20, 2021

MISSION VIEJO, Calif.—Invasive, ankle-biting mosquitoes are swarming Orange County, California, and the vectors will soon fill the 500 livable square miles in the county, according to the Orange County Mosquito and Vector Control District (OCMVC).

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Mosquitoes Infected With West Nile Virus Discovered in La Quinta

November 18, 2021

Mosquitoes infected with West Nile virus were discovered in La Quinta, officials announced Thursday.

The infected mosquitoes were collected from traps near Fritz Burns Park, at the intersection of Avenue 52 and Avenida Bermudas, according to the Coachella Valley Mosquito and Vector Control District. This is the second time mosquitoes in La Quinta have been positive with the virus this year.

“The warm temperatures this fall mean more mosquitoes later in the season,” said Tammy Gordon, Public Information Officer for the District. “You should invest in and wear insect repellent when enjoying the outdoors.”

There has been one human case of WNV in the Coachella Valley this year and 101 human cases in California overall. Eleven people have died from the virus this year, according to officials.

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How an Invasive Species Spreads: The Case of Aedes notoscriptus in Southern California

From Entomology Today
November 9, 2021

The mosquito Aedes notoscriptus is no longer a stranger to California. The Australian native was first reported in Los Angeles County in 2014, its first appearance outside of Australia, New Zealand, and the southwest Pacific. Of course, invasive insect species aren’t unusual (in California and elsewhere), but this species was noted for its rapid spread and easy adaptation to urban areas.

By 2019, immature and adult Ae. notoscriptus mosquitoes had been collected from 44 cities in three California counties. Yet, the mosquito—sometimes known as the striped mosquito or the Australian backyard mosquito—remains relatively understudied. Knowing how the species adapts (and how quickly) will help provide clues to managing it. This knowledge is also important because Ae. notoscriptus seems well poised to rapidly spread globally. In a paper published in October in the Journal of Medical Entomology, entomologists from vector control districts in Los Angeles and San Diego counties and the California Department of Public Health present findings on the spread and adaptations of the mosquito.

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Human infection of mosquito-borne illness found in Stanislaus County

From the Turlock Journal
November 9, 2021

A Stanislaus County woman has become the first person this year in the county to be diagnosed with St. Louis encephalitis virus, according to the Stanislaus County Health Services Agency.

The woman’s name and hometown were not released. She is in her 50s. She had neurologic symptoms and was tested in September; confirmatory testing was performed by the California Department of Public Health and recently released by the SCHSA.

As of the last state surveillance report of Nov. 5, St. Louis encephalitis virus has been detected in mosquitoes in eight California counties. The Stanislaus County woman is the one person in California testing positive for SLEV in 2021. SLEV is transmitted to humans by the bite of an infected mosquito. SLEV was detected in mosquitoes in Stanislaus County in September of this year. Most people infected with SLEV have no apparent illness. Initial symptoms of those who become ill include fever, headache, nausea, vomiting, and tiredness. Severe neuroinvasive disease (often involving encephalitis, an inflammation of the brain) occurs more commonly in older adults.

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A Solution to SoCal’s Mosquito Invasion: Sterilize the Males

From NBC Los Angeles
October 28, 2021

Southern Californians are being attacked by what officials say could be a record number of blood-sucking Aedes mosquitoes, also known as “ankle biters.”

“It’s absolutely the worst it’s ever been, and I’ve lived here for 25 years,” said LA resident Sheila Irani, showing the I-Team mosquito bites covering her ankles and legs.

The aggressive Aedes first appeared in our region about a decade ago, but they’ve spread significantly in recent years.

LA County Vector Control tells NBC4 they are now on track to get a record number of calls for help from homeowners who complain they’re being eaten alive by the ankle biters, which can penetrate clothing to reach their victims.

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Visit a factory that makes mosquitoes

From CBS Sunday Morning
October 24, 2021

The deadliest animal on Earth is not the shark, or the snake, or the scorpion, or even us. It’s the mosquito. The diseases they carry kill over a million people a year, and in a warming climate they’re spreading to new places.

In 2013, a particularly nasty species arrived in Fresno, California: aedes aegypti

“She’s evil,” said Jodi Holeman, who works for Fresno’s mosquito-control department. “This is a female that will bite you multiple times. She’s very, very aggressive. The one thing that you can say with great certainty is we don’t have any very strong methods of control for this particular mosquito.” 

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Second group of mosquitoes test positive for West Nile virus in Sonoma County

From KRON4
October 18, 2021

COTATI, Calif. (KRON) – A group of mosquitoes tested positive for West Nile virus, according to the Marin/Sonoma Mosquito and Vector Control District.

The district said on Monday that the adult mosquitoes were collected in traps in Sonoma County — This is the second sample group this year to test positive in the county.

This group was in the area of Santa Rosa Avenue and Burt Street in Santa Rosa, officials said.

Staff continues to search the area for new sources of mosquito production.

“District staff will continue to monitor the distribution and abundance of adult mosquitoes in the area where the positive mosquito sample was collected,” stated Nizza Sequeira, Public Information Officer. “The District will also continue to test viable adult mosquito samples collected in the area for WNV. In the meantime, we ask that residents report mosquito problems to our office and take personal protection measures such as wearing an effective mosquito repellent when engaging in outdoor activities.”

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Invasive Aedes mosquito expands reach in Los Angeles, Orange Counties

From the LA Times
October 11, 2021

County vector control personnel informed Graham Jenkins and his wife late last month that the itchy bites on their ankles were the work of an insidious mosquito that had invaded their Gardena home — and that there was nothing they could do.

“These little buggers are living with us forever now,” Jenkins said.

A pair of bites on the 34-year-old’s wrist recently got infected and sent him to the emergency room. After a week of antibiotics, he said he was “almost back to normal,” but still wearing his watch on the other wrist.

The invasive Aedes mosquito is an aggressive biter with the ability to pierce clothing and reproduce in water sources as small as a bottle cap. Flying low to the ground, they strike during the daytime, preferring human blood to that of birds or other animals. They often strike multiple times in rapid succession.

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Officials warn of invasive mosquito species surging in SoCal that aggressively bites humans

October 7, 2021

Los Angeles County authorities are warning residents that an invasive species of tropical mosquitoes is becoming more prevalent in the region.

The Aedes mosquitos are more aggressive against humans than other species in the area, and they’re difficult to get rid of because their ability to reproduce exponentially, experts say. They’ve also triggered a warning in the San Gabriel Valley and Orange County.

Vector control officials set up traps in neighborhoods around L.A. County to monitor the insects, and so far this year they’ve trapped the most in Sunland and Sun Valley.

People aren’t imagining it when they say they’re getting bit more this year, said Susanne Kluh, director of scientific and technical services for the Greater L.A. County Vector Control District.

The species has been in the region since 2011, but “depending on where you live, it might have just started really building up this year,” Kluh said.

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Sacramento area vector control warns of yellowjacket threat in area

From ABC10
September 29, 2021

ELK GROVE, Calif. — The Sacramento-Yolo Mosquito and Vector Control District is warning people about yellowjackets that have appeared in larger numbers than usual.

Yellowjackets stings are painful but the district warns that those allergic could have adverse reactions to them.  

“While this is not an unusual occurrence for fall, they do seem to be out in larger numbers this year especially compared to previous seasons,” Gary Goodman, District Manager for the Sacramento-Yolo Mosquito and Vector Control District, said in a news release.

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Alameda County logs year’s first West Nile virus activity

From the East Bay Times
September 27, 2021

Alameda County’s mosquito abatement district said Monday that a dead bird’s remains tested were positive for West Nile virus, the first positive test of the year.

The bird was collected in Pleasanton and underwent testing at a district laboratory. Officials said they plan to boost mosquito monitoring and larval control efforts near where the bird was found.

“With the change of season, residents may assume mosquitoes are no longer a threat, but this is usually the time of year when we see an increase in West Nile virus in our county,” district general manager Ryan Clausnitzer said.

“With light showers in the mornings followed by warm weather in the afternoons, mosquitoes still have plenty of opportunities to breed and flourish,” Clausnitzer said in part. “While we are not detecting high numbers of mosquitoes in the area where the bird was found, there is an increased risk of West Nile virus with every mosquito bite.”

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Birds, Mosquitoes With West Nile Virus Found In Contra Costa Co.

From the Concord, CA Patch
September 25, 2021

CONTRA COSTA COUNTY, CA — A second bird in Contra Costa County and another group of mosquitoes tested positive for West Nile Virus, county vector control officials said Friday.
The bird was found in San Pablo and the mosquitoes were in a trap in Oakley. It’s the first dead bird this year in San Pablo to have West Nile Virus.

So far this year in the county, two dead birds have been found with West Nile Virus as well as eight groups of mosquitoes.

Vector control officials said certain birds carry West Nile Virus and mosquitoes can become infected when they bite an infected bird. Mosquitoes spread the virus by biting another bird or a person.

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OC Reports First Human Case Of West Nile Virus For 2021

From CBS Los Angeles
September 23, 2021

SANTA ANA (CBSLA) – The Orange County Health Care Agency Wednesday confirmed its first human case of the year of West Nile Virus.

The Buena Park woman who contracted the virus was hospitalized earlier this month with neuroinvasive disease, but survived and is now recovering, the O.C. Health Care Agency reports.

According to the OCHCA, so far there have been fewer WNV cases reported this year compared to 2020, when there were 19 human cases and one death caused by West Nile.

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‘Ankle Biter’ Mosquito Population On The Rise In Orange County

From CBS Los Angeles
September 23, 2021

ALISO VIEJO (CBSLA) – The aedes mosquito, more commonly referred to as the “ankle biter,” has officially landed in all 34 Orange County cities.

“Me, I count…I see one, two, three, four, five, six just on this side and there are a whole bunch more under my sock,” said Aliso Viejo resident Andrew Smith

“Kind of classically itchy and I just felt a ton of bug swarming around my ankles. I was like, ‘This is not fun,’” said another Aliso Viejo resident, Sonoma Camozzi.

Experts say the “ankle biters” are multiplying and there’s and there’s no sign of them disappearing any time soon.

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Mosquito borne encephalitis virus found in Stanislaus County

From the Ceres Courier
September 22, 2021

A mosquito sample collected in Stanislaus County has tested positive for St. Louis Encephalitis virus, according to the area’s two mosquito abatement districts.

Like West Nile Virus, most people who become infected with SLEV will never feel sick. Most people who do feel sick will have mild flu-like symptoms; a small number of people will have severe disease with headache, confusion, disorientation and dizziness. Seizures, paralysis, coma and sometimes death may occur. Severe disease is more likely in people who are older and those with weakened immune systems.

SLEV is related to the West Nile Virus and is transmitted via the bite of Culex mosquitoes, the same mosquitoes that transmit WNV.

“The discovery of positive mosquito pools is a reminder that we need to continuously prevent mosquito breeding in our community. There is no specific treatment for SLEV or WNV, so it is very important that people protect themselves and their families from mosquito bites,” advises Dr. Julie Vaishampayan, Stanislaus County Public Health Officer. “We ask everyone to use mosquito repellents to protect themselves and their loved ones from mosquito-borne viruses, especially when they are outdoors.”

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Even California Has a Mosquito Problem

From the New York Times
September 22, 2021

When I moved to Los Angeles years ago, I was told by native Angeleno friends that the city without humidity also definitely did not have mosquitoes.

What is that whizzing sound then? The welts on my ankles? My favorite cafe has taken to selling bottles of insect repellent next to the cash register. Were my friends wrong, or should we acknowledge that this winged scourge is part of life in the Golden State? 

Since 2011, scientists have tracked an invasive mosquito species in parts of California: the Aedes aegypti. These black-and-white-striped “ankle-biters,” which can transmit dengue fever, Zika virus and yellow fever, have been found up and down the state.

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West Nile virus detected in mosquitoes and sentinel chickens in Lake County

From the Lake County News
September 22, 2021

LAKE COUNTY, Calif. — The Lake County Vector Control District said West Nile virus has been detected in two more mosquito samples and also in sentinel chickens in Lake County.

The sentinel chickens were in a flock near Upper Lake. The mosquitoes, all Culex tarsalis — the western encephalitis mosquito — were collected in traps set in Lower Lake and Upper Lake, the district reported.

Earlier this summer positive mosquitoes were collected near Kelseyville and Upper Lake, the district said.

“When we see West Nile virus in sentinel chickens, that tells us that the conditions are right for human infections of West Nile virus,” said Jamesina Scott, Ph.D., district manager and research director of the Lake County Vector Control District. “The best protection from West Nile virus is prevention. It’s important to avoid mosquito bites.”

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L.A. County could see more mosquitoes with hotter, longer summers

September 20, 2021

While many people might think mosquitoes are not a big deal in Southern California, where it’s not so humid, they should think again.

Public health officials say that the number of mosquito bites in the Los Angeles area has risen in recent years. And the hotter summers of the past few years may foreshadow conditions that boost the numbers of these small, blood-sucking pests.

That raises concerns about West Nile Virus, an incurable and potentially deadly mosquito-borne illness that can be transmitted to humans and animals.

L.A. County health officials on Monday reported this year’s first death linked to West Nile virus in the county. In 2020, there were 93 West Nile virus cases and seven deaths, according to public health data.

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L.A. County confirms its first West Nile virus-related death of 2021

From the Los Angeles Times
September 19, 2021

Los Angeles County health officials have reported the county’s first death this year due to West Nile virus.

The patient, a resident of the eastern region of the county, was hospitalized and died from a neuro-invasive disease associated with the virus, officials announced Friday. No further information was given about the individual or the date of death.

County officials have documented a total of 10 cases in the county so far this year, excluding Long Beach and Pasadena, which have their own health departments. The state reported its first West Nile virus-related death in July in San Luis Obispo County.

The mosquito-borne virus is common in California in summer and early fall. Most people who become infected don’t experience symptoms, according to the Centers for Disease Control and Prevention, but some may experience fever, muscle aches and tiredness. In severe cases of infection, especially in people over 50 years old and those with chronic medical conditions such as cancer and diabetes, the virus can affect the brain and spinal cord, causing meningitis, encephalitis and paralysis.

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Fresno County reports California’s first case in 2021 of this mosquito-borne illness

From the Fresno Bee
September 17, 2021

California’s first positive case of St. Louis encephalitis in 2021 has been reported and it’s in Fresno County.

The mosquito-borne illness, in rare and extreme cases, can cause inflammation of the brain, according to the Fresno County Department of Public Health.

A mosquito becomes infected and can pass it to humans when it bites a bird infected with the virus.

It is not transmitted person to person. Most people infected with SLEV don’t have symptoms, which can include fever, headache, or nausea up to two weeks after being bitten.

There were no details on the seriousness of the illness detected locally.

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Appreciating Placer Mosquito and Vector Control District’s efforts

From Gold Country Media
September 16, 2021

We’re lucky to have the expertise and efficiency shown year round by the Placer Mosquito and Vector Control District.

Although we often see the district’s trucks and employees in our neighborhoods, the district does not receive much public recognition for its success in eradicating invasive mosquito species from spreading throughout the area.

And we don’t usually reflect on the Placer Mosquito and Vector Control District’s around-the-clock efforts to stop the 30 mosquito species from multiplying here.

But if we find a mosquito that might carry a disease or we find a dead bird on our property, district employees are the first ones we call, as we expect immediate assistance.

So we appreciate the organization’s 26 employees working daily during mosquito season to keep potentially deadly or debilitating mosquito-borne diseases such as West Nile virus, yellow fever or Zika mosquitoes at bay. West Nile virus mosquito season is usually from mid-June to September or October, subsiding once temperatures are below 60 degrees. We’re still in the midst of mosquito season.

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Virus causing encephalitis found in Stanislaus County mosquito. Are humans at risk?

From the Modesto Bee
September 15, 2021

The virus that causes St. Louis encephalitis was detected in a mosquito sample in Stanislaus County, health officials said Wednesday.

The St. Louis virus is a relative of the West Nile virus, which gets attention in the Central Valley every year for causing a potentially deadly neurological illness in some residents.

In a small number of cases, St. Louis encephalitis may include symptoms such as headache, confusion, dizziness, seizures, paralysis or even death. But most people who become infected will not feel sick.

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West Nile virus-positive mosquitoes found in Palo Alto, Mountain View

From Palo Alto Online
September 15, 2021

The Santa Clara County Vector Control District, which monitors the transmission of vector-borne diseases from insects, will be treating parts of Palo Alto and Mountain View with insecticide after recently detecting West Nile virus-positive mosquitoes in limited areas of the two cities.

Weather permitting, the district will use trucks to spray the impacted areas on Friday, Sept. 17, starting around 10 p.m., according to a county press release. The process should take three hours.

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7 groups of mosquitoes test positive for West Nile Virus in Contra Costa this year

From KRON4
September 10, 2021

BRENTWOOD, Calif. (KRON) – Two more groups of mosquitoes tested positive for West Nile Virus, according to the Contra Costa Mosquito and Vector Control District.

Both groups were collected in eastern Contra Costa County: Holland Tract and an agriculture area near Brentwood.

There are now seven groups of mosquitoes and a dead bird that have tested positive for the virus in Contra Costa County this year.

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Madera County reports its first West Nile Virus death of 2021. ‘It is a reminder of the risks’

From the Fresno Bee
September 10, 2021

A man has died after contracting West Nile Virus in Madera County, the first reported fatality from the illness in the county this year.

The death was from one of the first two cases found in August, according to the county Department of Public Health.

Both cases required hospitalization, but the second person has recovered and been discharged. The two cases were considered unrelated.

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First Case of West Nile Virus Reported in Long Beach

From the California News Times
September 7, 2021

The first human case of West Nile virus (WNV) during this mosquito season was reported at Long Beach this week. The patient is in his 40s and has been diagnosed with a neuroinvasive disease and is currently recovering at home.

“This is an important reminder to keep people from being bitten by mosquitoes,” said Dr. Anissa Davis, City Health Officer. “Everyone needs to take steps to prevent mosquito-borne diseases.”

There are 32 cases of WNV reported in California this year, and 5 in LA County. Long beach mosquitoes have not been known to be positive for WNV so far this season.

WNV is transmitted by being bitten by an infected Culex pipiens. Signs and symptoms of WNV include fever, body aches, rashes, nausea, vomiting, and headaches. Most infected people have no symptoms. One in 150 people can develop more serious illnesses such as inflammation and paralysis of the brain. People with these symptoms need immediate treatment.

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Dead bird tests positive for West Nile virus in Contra Costa

From KRON4
September 3, 2021

CONCORD, Calif. (KRON) – The first dead bird in 2021, in addition to more mosquitoes, have tested positive for West Nile virus, according to the Contra Costa Mosquito and Vector Control District.

A California scrub-jay was found in Brentwood and the mosquitoes were nearby in Discovery Bay.

This year in Contra Costa County, five groups of mosquitoes and now one dead bird have tested positive for the virus.

Officials say some birds carry the virus and if a mosquito bites the bird and becomes infected, the mosquito can spread it to another bird or person.

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Invasive mosquitoes still active in Sacramento. Where they’re biting before Labor Day holiday

From the Sacramento Bee
September 2, 2021

A new invasive mosquito taking root in the Sacramento region during a busy year for West Nile virus has local vector officials on the lookout ahead of the Labor Day weekend.

The mosquito Aedes aegypti was spotted for the first time this week in Elk Grove and in Orangevale, said Sacramento-Yolo Mosquito and Vector Control District officials, joining known breeding grounds in the Arden Arcade area and in Winters in Yolo County. Vector district officials reported the first sightings of the invasive mosquitoes in 2019 in Citrus Heights.

The sightings come as West Nile virus activity has been, in officials’ words, “steady and widespread” in both Sacramento and Yolo counties.

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5 horses in Central Valley test positive for West Nile virus; one dies

From Fox KTVU
September 2, 2021

The California Department of Food and Agriculture reported Wednesday that five horses in the Central Valley have tested positive for West Nile virus, leaving one horse dead.   

According to the CDFA report, the horses carrying the virus were located in Fresno, Sacramento, Merced and Kings counties and only one horse was vaccinated against West Nile virus.   

Some symptoms of West Nile virus in horses include animals having a fever, uncoordinated limbs, generalized weakness, drooping lips, grinding teeth, and hypersensitivity to touch or sound.  

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West Nile virus widespread in Butte County

From the Chico Enterprise-Record
August 31, 2021

CHICO — In Butte County, seven new pools of West Nile virus have been found while four sentinel chickens have tested positive for the virus. The West Nile virus has resulted in one death in Butte County so far this year.

Butte County Mosquito and Vector Control District said the virus is considered “widespread” among mosquitoes in the county with this year seeing 76 positive pools. The highest year on record was 2015 when 101 mosquito pools with active cases of West Nile virus were found.

“2015 was the fourth year of the drought,” said Butte County Mosquito and Vector Control District Manager Matt Ball. “One would think droughts mean less mosquitoes therefore there should be less virus. Well, here in Butte County, droughts actually mean propagation of the virus and it means more artificial water, flooding and irrigating sooner than natural weather. We actually see more mosquitoes and more virus on drought years than when we get a nice cool wet spring.”

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Bird found in Simi Valley tests positive for West Nile virus

From the VC Star
August 30, 2021

A bird collected in Simi Valley has become the first of 2021 to test positive for the West Nile virus in Ventura County, health officials said Monday.

The Ventura County Environmental Health Division said the bird was collected in the city during the third week of August. The California Department of Public Health recently confirmed the positive test result.

The division monitors mosquito-breeding sources in the county and said the area where the infected bird was found will be inspected and treated if necessary.

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West Nile Virus Found in Santa Clara, Sunnyvale Mosquitos

From CBS SF Bay Area
August 27, 2021

SANTA CLARA COUNTY (BCN) — Some adult mosquitos in Sunnyvale and Santa Clara have tested positive for the West Nile virus, following positive test results among mosquitos in Gilroy.

Santa Clara County’s Vector Control District confirmed this week that West Nile virus-ridden mosquitos were found in portions of the 94086, 94087 and 95051 ZIP codes.

To prevent its spread to humans, truck-mounted spray treatment has been scheduled in the area. Weather permitting, the treatment will start at 10 p.m. on Monday and take a few hours to complete.

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Learn How to Eliminate Mosquitoes, Prevent Bites During Webinar for Local Residents Set for Thursday

From Pasadena Now
August 25, 2021

The San Gabriel Valley Mosquito and Vector Control District (SGVMVCD) will teach local residents about mosquito prevention techniques, including choosing the right repellent through an online webinar this week.

According to SGVMVCD communications director Levy Sun, the mosquito control district has decided to hold the “Bite Back Tour” webinar as the expected warmer weather in cities across the San Gabriel Valley, including Pasadena, may bring a rise in mosquito and West Nile Virus activity.

The SGVMVCD will make stops in cities across the San Gabriel Valley to show residents how they can best protect themselves from mosquitoes, according to Sun.

“This is the first year we conducted this tour in response to people wanting access to mosquito safety information in a virtual on-demand and live format,” said Sun.

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Positive Tests Confirm West Nile Virus Mosquitoes

From the Santa Clara County News
August 24, 2021

Targeted treatment scheduled for Thursday, August 26 in limited area in Gilroy

SANTA CLARA COUNTY, CALIF. – The County of Santa Clara Vector Control District has confirmed West Nile virus (WNV) positive tests in adult mosquitoes collected from portions of the 95020 ZIP code area that includes part of Gilroy. As a result, a truck-mounted adult mosquito control treatment has been scheduled in the area to prevent human cases of WNV. Weather permitting, the ground operations are scheduled for approximately 10 p.m. on Thursday, August 26, and will conclude a few hours later. The District is adhering to all recommendations from the Centers for Diseases Control and the County of Santa Clara Public Health Department regarding the Coronavirus (COVID-19) and will be conducting the treatment in accordance with those guidelines.

Door hangers notifying the public of the scheduled mosquito treatment will be placed in neighborhoods beginning Tuesday, August 24. Notice is also being sent directly to the public in the treatment ZIP codes through AlertSCC, and to those who subscribe to Nextdoor neighborhood networks. General notice also is being provided on various social media platforms, including Mailchimp email notification, Facebook, Instagram, and Twitter (@SCCVCD).

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One human case confirmed of West Nile Virus in Merced County

From the Merced County Times
August 22, 2021

Merced County Department of Public Health officials notified Merced County Mosquito Abatement District (District) that a male in his 60s contracted West Nile Virus (WNV) fever in the City of Merced. This is the first human case of WNV in the County this year. In addition to the human case, the District has detected WNV in one (1) sentinel chicken, one (1) mosquito pooled sample, and one (1) dead bird to date in Merced County. As of Aug. 6, 2021, eight (8) human cases have been confirmed in California.

West Nile Virus is transmitted through the bite of an infected mosquito. County residents are encouraged to continue their efforts to reduce mosquito breeding and WNV prevention by taking the following steps:

  • Eliminate sources of standing water where mosquitoes lay their eggs.
  • Avoid spending time outside when mosquitoes are most active (dawn and dusk).
  • Apply insect repellent containing the active ingredient DEET when outdoors, according to label 
instructions. In addition to DEET-based products, the Centers for Disease Control (CDC) also recommends insect repellant containing oil of lemon eucalyptus and Picaridin.

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This California town is being attacked by ‘ninja mosquitoes’

From Fox 5
August 19, 2021

TULARE COUNTY, Calif. (KSEE/KGPE) — Residents who live in part of California’s Central Valley say they are hoping a slight increase in their property taxes will mean getting a break from an invasive species of mosquito.

According to the Delta Mosquito Vector Control District, “Aedes aegypti” is an invasive species of mosquito that have made its way into many counties in California. They are aggressive, day-biters found both indoors and outdoors, and they especially like to feed on ankles, wrists, and elbows.

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Human case of West Nile Virus found in Merced County

From Westside Connect
August 19, 2021

The Merced County Department of Public Health has confirmed the first human case of West Nile Virus in the county. 

A man in his 60s contracted West Nile Virus fever in Merced. This is the first human case of WNV in the county this year. 

In addition to the human case, the Merced County Mosquito Abatement District has detected WNV in one sentinel chicken, one mosquito pooled sample, and one dead bird. 

As of Aug. 6, eight human cases have been confirmed in California. 

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Invasive mosquitoes potentially carrying yellow fever, other diseases reach Sutter County

From the Sacramento Bee
August 13, 2021

The invasive species of mosquitoes that were reported flying through California were spotted in Sutter County this week, public health officials announced.

The Aedes aegypti, also called the “ankle biter,” were detected in the Yuba City area Wednesday, according to a news release from the Sutter-Yuba Mosquito and Vector Control District (SYMVCD).

The release said the mosquitoes, if spotted, will look unfamiliar to most people. A quarter-inch long, these black-and-white-striped mosquitoes are stealthy and aggressive biters during the day, and they lay eggs that look like small black seeds. Diseases control experts say the mosquitoes carry diseases such as dengue, chikungunya, Zika and yellow fever.

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Orange County Finds First Batch of West Nile Virus-Infected Mosquitoes This Year

From NBC Los Angeles
August 8, 2021

The first batch of mosquitoes infected with West Nile virus in Orange County this year have been found in Fullerton, officials said Friday.

The samples were taken on Tuesday and the test results came back positive Thursday evening, said Heather Hyland, public information officer of the Orange County Mosquito and Vector Control District.

The samples were recovered at Chapman Avenue and Ladera Vista Drive and Woodcrest and Richman avenues.

Mosquitoes get infected from birds and then pass it on to humans.

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First Human West Nile Virus Infection Confirmed In County

From the Oakdale Leader
August 6, 2021

Stanislaus County Public Health has confirmed the first human West Nile virus (WNV) infection in the county. An adult female was diagnosed with West Nile fever (non-neuroinvasive disease). The first pools of mosquitoes in the county tested positive for West Nile virus on June 11, 2021.

West Nile virus spreads to people and animals through the bite of a mosquito infected with the virus. Hot weather, abandoned swimming pools, and standing water create ideal conditions for the development of mosquitoes and the subsequent spread of the virus. About one in five people will develop West Nile fever with symptoms of headache, fever, and fatigue. However, some people (less than one percent) will develop serious neurologic illness, such as encephalitis or meningitis.

People 50 years of age and older have a higher chance of getting sick and are more likely to develop serious illness when infected with WNV. Studies also indicate that those with diabetes and/or hypertension are at greatest risk for serious illness. There is no specific treatment for WNV disease. 

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Invasive species of mosquito that transmits several diseases spotted in Ventura County

From ABC7
August 5, 2021

Health officials in Ventura County have detected an invasive mosquito capable of transmitting several viruses, like yellow fever and Zika.

There is no confirmed transmission of the diseases in our state but experts say you still want to avoid being bitten.

Since September of last year, Aedes aegypti mosquitoes have been found in several communities including Simi Valley, Thousand Oaks, Oak View, Oxnard, and now Ojai.

Health officials warn the public to take steps to avoid mosquito bites and to avoid providing breeding places for mosquitoes in standing water, such as bird baths and fountains and other outdoor locations where water may pool and become stagnant.

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‘Ankle biter’ mosquito breeding on the rise throughout Southern California

From ABC7
August 5, 2021

GARDEN GROVE, Calif. (KABC) — The Orange County Mosquito and Vector Control District is seeing a greater number of “ankle biter” mosquitoes this summer.

Lora Young, the director of communications for OCMVCD, said these pesky pests are mostly noticeable because they’re the ones causing pain throughout Southern California.

“Especially with the Aedes mosquito. They’re a very aggressive day-biting mosquito and they prefer to bite people where our other mosquitoes prefer to bite birds,” Young said.

Young said numbers for the southern house mosquito – that’s the one able to carry West Nile Virus – are trending about average when compared to the last five years.

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From NBC Palm Springs
August 5, 2021

Mosquitoes infected with West Nile virus were discovered in La Quinta, officials announced Thursday.

The infected mosquitoes were collected from traps near Avenue 52 and Jefferson Street, according to the Coachella Valley Mosquito and Vector Control District.

“It’s not worth the risk. It only takes one bite from an infected mosquito to make you sick.” said Tammy Gordon, a district spokeswoman. “Know your risk and wear insect repellent to reduce the risk of getting sick.”

So far this year, district technicians have collected mosquitoes infected with WNV from nine traps, mostly on the northern edge of the Salton Sea in the communities of Mecca and North Shore.

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West Nile Virus Detected In Solano County

From the Benicia Patch
August 4, 2021

SOLANO COUNTY, CA — Two mosquito pools have tested positive for West Nile virus in Solano County, marking the official start of the West Nile virus season in the county, officials said Wednesday.

The specimen samples were collected July 30 in southern Davis, Solano County.

Although no human cases were confirmed in the county as of July 30, the California Department of Public Health reported that four people have tested positive for the West Nile virus across the state.

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Lake County mosquitoes test positive for West Nile virus

From the Lake County News
August 3, 2021

LAKEPORT, Calif. — For the first time this year, mosquitoes have tested positive for West Nile virus in Lake County.

The mosquitoes, Culex tarsalis (western encephalitis mosquito), were collected in traps near Upper Lake on July 21, the Lake County Vector Control District reported.

“West Nile virus activity is increasing statewide, including in Lake County,” said Jamesina Scott, Ph.D., district manager and research director of the Lake County Vector Control District. “This serves as a reminder to avoid mosquito bites to avoid West Nile virus.”

Scott said mosquitoes thrive in still water. Dump out or drain water in backyard water sources, or contact the district for free mosquito-eating fish for water that can’t be drained, like unmaintained (green) swimming pools and spas, ornamental ponds, or animal watering troughs, she advised residents.

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First human case of West Nile virus for 2021 reported in Stanislaus. How to be safe

From the Modesto Bee
August 3, 2021

Stanislaus County announced its first human case of West Nile virus this year, a woman with a moderate form of the disease.

The age and hometown of the woman were not disclosed in Tuesday’s news release from county Public Health. It urged residents to guard against the mosquitoes that carry the virus.

California had four other symptomatic infections this year as of July 30, according to the weekly update from the state Department of Public Health. They include a person who died in San Luis Obispo County and nonfatal cases in Shasta, Fresno and Kern counties.

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