Mosquito & Vector News

West Nile Virus infected Mosquitoes found in Palm Springs

October 16, 2017

PALM SPRINGS, Calif. – For the second time in Palm Springs this year, a sample of mosquitoes have tested positive for West Nile.

The Coachella Valley Mosquito and Vector Control District positive sample contained 16 mosquitoes from a trap located near Mesquite Avenue and Gene Autry Trail.

The District will post disease notification signs in communities located in the area where the mosquitoes were trapped and will increase mosquito surveillance.

Technicians will also carry out larval and adult control in the surrounding area in an effort to reduce the number of mosquitoes and interrupt further virus transmission. 

Residents can reduce mosquitoes by draining standing water, installing or repair screens, and applying insect repellent.

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Aedes aegypti mosquito detected in Mecca

October 11, 2017

MECCA, Calif. – Mecca has become the latest city in the valley to be detected with the Aedes aegypti mosquito.

The Coachella Valley Mosquito and Vector Control District detected three adult mosquitoes and 37 mosquito larvae in a Mecca neighborhood that were identified as an invasive mosquito species capable of transmitting serious viruses such as chikungunya, dengue, yellow fever, and Zika.

While these viruses are not currently transmitted locally, the District is taking steps to reduce the spread of this mosquito throughout the Coachella Valley.

Beginning Oct. 16, the District will conduct increased trapping in the area to evaluate the extent of the infestation and technicians will start a door-to-door campaign searching for standing water sources in people’s backyard where this mosquito species commonly lays eggs.

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Disease-Transmitting Aedes Mosquito Prompts Santa Clarita Public Information Session

From KHTS AM 1220
October 10, 2017

The disease-transmitting Aedes mosquito has been confirmed in the Santa Clarita area, prompting city officials to host a Public Information Session about the species.

The session will be held at the City Hall Council Chambers on October 23, from 6:30 p.m. to 7:30 p.m.

Officials will be discussing combative measures to control the Aedes mosquito species locally. Residents will be offered tips to protect themselves and their families.

Public Information Officers Levy Sun and Wesley Colling from the Greater Los Angeles County Vector Control will be there to discuss protection options for residents and business owners.

“Residents, businesses, property management companies and landscapers are encouraged to attend this meeting,” a city news release stated.

The Greater Los Angeles Vector Control District tells residents that the Aedes mosquito is a public health concern because they can transmit Zika virus, dengue fever, yellow fever and chikungunya.

The Aedes mosquito is known to bite during the day, live in cities and thrive indoors and outdoors, the city news release said.

For additional information regarding the session, please contact Levy Sun at (562) 325-3271. For more information about Aedes mosquitoes, visit the Greater Los Angeles County Vector Control District website here.


From Contra Costa MVCD
October 10, 2017

More dead birds, chickens, and mosquitoes test positive for the virus
CONCORD, CALIFORNIA – –  The Contra Costa Mosquito & Vector Control District is reporting two more dead birds, two more chickens, and another group of mosquitoes have tested positive for the virus.
The mosquitoes and one chicken were from an area near Knightsen and another chicken was from Martinez. The dead birds were collected from Martinez and Walnut Creek. 
For a list of all 2017 West Nile virus activity and locations, visit the  District’s website
“The cooler weather is arriving, which is good news,” said Deborah Bass, public affairs manager. “That slows down mosquito production as well as the virus.” 
District personnel are conducting extra surveillance and mosquito control in the areas where virus activity was found.

Orange County records its first West Nile virus-related death

From The Orange County Register
October 6, 2017

The peak season of the mosquito-borne West Nile virus should be nearing its end, but state and local agencies are warning people to keep up the fight against mosquitoes.

There were 47 new cases of the disease reported across the state in the past week. Nearly all were in Southern California. Orange County recorded its first West Nile virus-related fatality Oct. 6.

You can see the state totals here.

The Mosquito and Vector Control Association of California is warning people that West Nile virus cases have spiked this fall in Southern California, and three deaths from the disease were reported last month. In addition to fatalities, 88 percent of the reported infections in Los Angeles County have required hospitalizations.

Peak season
Cases of West Nile virus in 2016 by week in the U.S.
Most cases of the virus are reported in the warm summer months, but local vector agencies are warning people of a spike in cases this fall.

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Four chickens near Redding catch West Nile virus

From The Record Searchlight
October 3, 2017

Four “sentinel chickens” east of Redding have tested positive for West Nile virus, according to the Shasta Mosquito and Vector Control District.

The district keeps flocks of chickens in various locations within the district as disease sentinels. The presence of the virus in chickens indicates “this is a sign of increased risk to people from West Nile virus,” the district said in a news release.

“Even though temperatures are dropping, we are still actively trapping mosquitoes that have the potential to transmit West Nile virus. If you plan to be outside during dusk or dawn, it is imperative you continue to protect yourself from mosquito bites,” cautioned Peter Bonkrude, district manager of the Shasta Mosquito and Vector Control District.

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October 3, 2017
Two Contra Costa County residents also test positive for the virus
CONCORD, CALIFORNIA – –  The Contra Costa Mosquito & Vector Control District is reporting five dead birds, a group of mosquitoes, and a chicken that have tested positive for West Nile virus. In addition, the District received notice from public health officials that two people, one from East county and one from Central county also tested positive for the virus. 
For a list of all 2017 West Nile virus activity and locations, visit the District’s website
The mosquitoes were collected from an area near Knightsen and the chicken from Martinez. The dead birds were collected from Pleasant Hill, Martinez, and Walnut Creek. 
“The West Nile virus season isn’t over yet,” said the District’s Scientific Programs Manager Steve Schutz, Ph.D. “People need to take precautions against mosquito bites. Please take our guidelines seriously.” 
District personnel are conducting extra surveillance and mosquito control in the areas where virus activity was found.

Controlling mosquitoes through aerial management

From Sierra Wave Media
October 2, 2017

OVMAP news release

Recent mosquito trap data indicate that recent aerial larviciding treatments were very successful, with mosquito populations reduced by about half in the two weeks following aerial management activities.

To illustrate the scope of what was conducted during aerial management Rob Miller, OVMAP Interim Manager, stated that “OVMAP applied roughly 10 times the
amount of material used in a year in just two days” via helicopter.

This larvicide works by introducing naturally-occurring bacteria into breeding habitat, stopping normal mosquito larval development and preventing these larvae from becoming biting adult mosquitoes.

Since the bacteria only target certain species of mosquito larvae, it is safe for use around animals, plants, and other insect species. Control should last from 30 to 60 days.

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WVMVCD Media Release: Invasive Mosquito Alert: Aedes albopictus Detected in Montclair

From West Valley MVCD
October 2, 2017

The West Valley Mosquito and Vector Control District has detected the presence of Aedes albopictus, commonly known as the Asian tiger mosquito, in Montclair. This detection occurred during routine surveillance near Kingsley and Ramona Ave.

Aedes albopictus are small, black and white mosquitoes that will aggressively pursue people during the day and the evening. They prefer to lay eggs in man-made receptacles such as tires, fountains, potted plants, and birdbaths. Asian tiger mosquitoes lay their eggs singly on the sides of containers, usually just above the water line, and when the eggs meet with water, they activate and hatch. They are not solely outdoors either, they will lay eggs in containers inside homes as well.

Aedes albopictus are an important species because they are known transmitters of West Nile virus, Dengue, and Zika virus. They have been spreading rapidly throughout Southern California, and have the potential to be a serious vector in our region.

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Deadly West Nile virus cases are spiking in LA. The first line of defense: chickens

From Stat News
September 29, 2017

EL MONTE, Calif. — The chickens are used to the needles.

They don’t fuss when vector ecologist Tanya Posey pulls opens the door of a coop in a community garden here, firmly grasps a Leghorn, and pulls a blood sample out of its wing vein. She’s so good, she can bleed a chicken in about 30 seconds.

That’s helpful, because she has a lot of chickens to test.

More than six dozen sentinel chickens, living in coops dotted around Los Angeles, make up one of the first lines of defense in this sprawling county’s fight against West Nile virus. The disease has been a background threat for years here, but cases have spiked this fall to worrisome levels. Six deaths have been reported by Los Angeles County this year — including three just last week.

And the cases are alarmingly severe: Of 98 reported infections here this year, 79 have led to serious neurological side effects, and 87 have required hospitalization. Because it’s still peak mosquito season, more deaths are expected.

So local public health officials this week launched an all-out attack. They’re sending teams of green-shirted vector control agents door to door to tell residents to wear bug spray, install window screens, and dump the stagnant water where the insects breed. They’re plastering the county with posters that read “It’s Not Just a Bite” and “No Es Solo Un Piquete.” They’ve even created a rap video featuring a fetid swimming pool, a giant dancing mosquito, and teams of uniformed agents rapping, “You’ve got to dump the water out, drain the water flow, tip the water out, toss the water slow.”

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West Nile virus targeted in Sepulveda Basin as public health concerns heighten

From The Los Angeles Daily News
September 27, 2017

Vector control agents conducted a pre-dawn raid on adult mosquitoes in the Sepulveda Basin on Wednesday to knock down the populations in an effort to reduce the spread of West Nile virus.

The truck-mounted, ultra-low volume fogging in the Sepulveda Basin recreation area should not affect any visitors to the area who use the trails, said Kelly Middleton, a spokeswoman for the Greater Los Angeles County Vector Control District.

She said the product used to eradicate the insects is a synthetic, man-made chemical based compound called pyrethrins found in chrysanthemums.

“One of the reasons we use these products is it’s very effective against these (mosquitoes),” she said. “There are no concerns for exposure for people. The pesticide is only effective a short period of time.”

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SoCal mosquito season brings disease danger

From ABC 7
September 26, 2017

Several people have died this year from the West Nile Virus in Southern California. With mosquito season in full swing, local public health experts issued a warning about the serious health concern.

A campaign to spread awareness about the continued risk of mosquito-borne diseases, like West Nile and Zika, launched today in Los Angeles County.

Fourth District Supervisor Janice Hahn said there have been 98 individual cases of the West Nile virus and six confirmed deaths in the area so far.

“Mosquitoes can carry serious and even deadly diseases and every precaution should be taken to protect yourself and your family from bites,” Hahn said.

Hahn will go door to door with the L.A. County Department of Public Health educating residents on how to better protect themselves. The first step is to get rid of any standing water and also the containers that held the water.

Officials said educating the public about the dangers of mosquitoes is especially important because peak season for mosquitoes can last well into November, if the weather stays warm.

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Yellow fever mosquito found in Tulare

From The Porterville Recorder
September 25, 2017

The yellow fever mosquito has been found in the City of Tulare by the Tulare Mosquito Abatement District, the Tulare County Health and Human Services Agency reported.

Aedes aegypti, also known as the yellow fever mosquito, is capable of transmitting several human diseases, including dengue, chikungunya, yellow fever and Zika, stated Tammie Weyker-Adkins, public information officer with the county HHSA. This mosquito is not native to California and is the first detection in the City of Tulare. Since 2013 Aedes aegypti has been detected in 13 California counties.

“Our goal is to mitigate the spread of these invasive mosquitoes to other areas of Tulare or the county at large. Having Aedes aegypti in our district is very concerning as it is an efficient vector in spreading Zika, dengue, chikungunya, and yellow fever viruses,” said John Avila, General Manager of the Tulare Mosquito Abatement District.

The Tulare Mosquito Abatement District is working with the California Department of Public Health (CDPH) in addition to the Tulare County Public Health Department to evaluate the extent of the infestation and will aggressively target problem areas to prevent its spread, Weyker-Adkins stated. These efforts will include door-to-door inspections of residential properties for standing water where mosquitoes can breed, increased surveillance through trapping, eliminating mosquito breeding sources, larval control, and ultra low volume fogging as necessary to target the invasive mosquitoes. Fogging will begin immediately in the infestation area.

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Press Release From Merced County MAD
September 25, 2017

MERCED, CA– The Merced County Mosquito Abatement District identified Aedes aegypti, also known as the yellow fever mosquito, in the city of Merced (zip code 95340). This mosquito is capable of transmitting several human diseases, including dengue, chikungunya, yellow fever, and Zika. This mosquito is not native to California and is the first detection in Merced County. Since 2013, Aedes aegypti has been detected in 13 other California counties, primarily south of Merced.

The Merced County Mosquito Abatement District is working with the California Department of Public Health in addition to the Merced County Public Health Department to evaluate the extent of the infestation and will aggressively target problem areas to prevent its spread. These efforts will include door-to-door inspections of residential properties for standing water where mosquitoes can breed, increased surveillance through trapping, eliminating mosquito breeding sources, larval control, and ultra-low volume adulticiding (fogging) as necessary to target the invasive mosquitoes. Fogging will begin immediately in the infestation area.

“Our goal is to mitigate the spread of these invasive mosquitoes to other areas of Merced or the county at large. Having Aedes aegypti in our District is very concerning as it is an efficient vector in spreading Zika, dengue, chikungunya, and yellow fever viruses,” said Rhiannon Jones, General Manager of Merced County Mosquito Abatement District. While these viruses are not currently transmitted in California, they are periodically introduced by international travelers. If a large population of Aedes aegypti is established in the area, a single travel-associated case of one of these diseases could introduce the virus to local mosquitoes, and Merced County residents could be at risk of becoming infected.

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West Nile virus has killed 8 Californians this year. In parts of L.A. County, the risk is especially high

From The Los Angeles Times
September 23, 2017

Julie Shepherd ended up in the hospital earlier this month after her neighbor found her on the floor of her West Covina home, unable to move.

Shepherd, 84, was paralyzed and had lost the ability to speak. Doctors diagnosed her illness as West Nile virus.

Humans contract the virus through a mosquito bite. There’s no vaccine or cure for the disease, so Shepherd’s family could only wait to see if she recovered on her own.

“Other than treating the symptoms, there’s no treatment,” said Halie Griffin, Shepherd’s granddaughter. “[The doctors] told us that within 10 to 15 days either you’ll see improvement, or you won’t.”

Shepherd was unable to fight off the virus and died Monday.

West Nile virus has killed three people in Los Angeles County this year. It’s the deadliest mosquito-borne disease in California. Though most people with West Nile virus don’t have symptoms, a small number experience brain damage that can be permanent or fatal.

L.A. County officials are warning residents to take precautions to prevent mosquito bites, especially since West Nile cases tend to be highest in September.

“Everybody needs to be concerned,” said Dr. Benjamin Schwartz, deputy director of the L.A. County public health department’s acute communicable disease program. “This is really the peak season for West Nile in Los Angeles County.”

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Mosquitoes spread deadly diseases, and public health experts hope to fight back with this new emoji

From The Los Angeles Times
September 22, 2017

Mosquitoes are more than a spoiler of backyard barbecues. They threaten more than half the world’s population with their disease-spreading bites. In fact, mosquitoes are deadlier — by far — than sharks and snakes.

They are the incubator and chief disseminator of malaria, dengue and yellow fevers, as well as newer scourges like the West Nile and Zika viruses. Their numbers explode with floods, hurricanes and climate change, allowing them to outnumber every animal on Earth during their peak breeding season. Public-health officials fret about them 24/7.

So how is it that this fearsome creature has no emoji?

Check your phone: You’ve got a honey bee, a caterpillar, a spider, an ant and a ladybug, not to mention all manner of mammals, birds and sea creatures.

But no mosquito.

That oversight cries out for a fix, according to a pair of public-health specialists. That’s why they have petitioned a group called the Unicode Consortium to include a female mosquito — the only kind that bite humans and spread disease — in the next batch of emojis that will be available on smart phones next year.

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Move over malaria: Mosquitoes carrying Zika, dengue may thrive in warmer Africa

From Reuters
September 21, 2017

DAKAR, Sept 22 (Thomson Reuters Foundation) – From deadly droughts and destroyed crops to shrinking water sources, communities across sub-Saharan Africa are struggling to withstand the onslaught of global record-breaking temperatures.

But the dangers do not end there. Rising heat poses another threat – one that is far less known and studied but could spark disease epidemics across the continent, scientists say.

Mosquitoes are the menace, and the risk goes beyond malaria.

The Aedes aegypti mosquito, which spreads debilitating and potentially deadly viruses, from Zika and dengue to chikungunya, thrives in warmer climates than its malaria-carrying cousin, known as Anopheles, say researchers at Stanford University.

In sub-Saharan Africa, this means malaria rates could rise in cooler areas as they heat up, but fall in hotter places that now battle the disease. In those areas, malaria – one of the continent’s biggest killers – may be rivalled by other vector-borne diseases as major health crises.

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Multiple cases of West Nile virus in Glendale prompt education campaign

From The Los Angeles Times
September 21, 2017

With eight cases of West Nile virus reported in Glendale so far this year, health officials took part in a door-to-door education campaign Wednesday, informing residents of what they can do to protect themselves from infection.

Conducted by the Greater Los Angeles County Vector Control District, the effort informed residents in Glendale, Los Feliz and Atwater Village about the preventive measures they can take to reduce the risk of being bitten by mosquitoes. Levy Sun, a spokesman for vector control, said wearing insect repellent and dumping out any stagnant water near homes are measures people should take regularly. 

He said those actions were specifically targeted in the campaign because of the high concentration of people with West Nile virus in Glendale. Additionally, Sun said three traps set up by vector control officials in Glendale all turned up positive for the virus.

“We are now in the peak of mosquito season,” he said. “We can see it lasting until late November if the weather continues to stay warm.”

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Family of West Covina Woman Killed by West Nile Virus Speak Out After Infection Claims 6 Lives in California This Year

September 20, 2017

Just as Ventura County health officials warned of mosquitoes found infected with West Nile Virus on Wednesday, a family a county away in West Covina spoke out about the illness killing one of their own.

Julie Shepherd, 84, was a lively grandmother who loved aerobics and Tai Chi before she became infected with West Nile Virus, her daughter told KTLA. She was hospitalized for two weeks, never even realizing she was bitten by a virus-laden mosquito, before she died just two days ago.

“It was so heartbreaking that nobody should have to go through that,” her daughter, Suzi Howe, said.

West Nile Virus is an infection carried by mosquitos and birds that does not cause illness in most people infected. There is no vaccine to protect against it.

However, a small number of those infected will develop symptoms such as “fever, headache, rash, muscle weakness, and nausea and vomiting,” Los Angeles County health officials say, and some may even experience serious neurological symptoms such as “limb paralysis, tremors, and altered mental status.”

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Aedes aegypti mosquito detected in Palm Desert

September 20, 2017

PALM DESERT, Calif. – The Aedes aegypti mosquitoes — capable of transmitting chikungunya, dengue, yellow fever and Zika — has been found in Palm Desert.

While these viruses are not currently transmitted locally, the Coachella Valley Mosquito and Vector Control District is taking steps to eliminate and reduce the spread of this mosquito throughout the Coachella Valley. 

District teams will be conducting enhanced surveillance in the area to evaluate the extent of the infestation. Technicians will also be going door-to-door searching for standing water sources in people’s backyard where this mosquito species commonly lays eggs.

Technicians will educate residents on how to prevent breeding and also carry out control activities as needed. The door-to-door campaign will be carried out within the area bordered by Fred Waring Drive, Monterey Avenue, Avenida Las Palmas, and Highway 111.

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Increase in mosquito population throughout Orange County — particularly in Santa Ana — has vector officials on alert

From The Orange County Register
September 19, 2017

SANTA ANA – Wilshire Square resident Raul Ramos was tossing out trash in his backyard on a Saturday two weeks ago when he noticed some standing water. Then he noticed he had mosquito bites.

A few hours later, he was rushed to the hospital with symptoms that included nausea and aching all over his body. He was hospitalized for a week, and for four days had a 105-degree fever.

“I called the vector department. All the symptoms on their brochure, I had,” Ramos, 62, said Tuesday, Sept. 19 from his home on the 2100 block of South Birch Street.

Though it’s unclear whether the mosquito bites led to Ramos’ illness, the incident underscores the need for residents to be cautious.

The Orange County Mosquito and Vector Control District posted up at Ramos’ home on Tuesday to get the word out about a significant increase in invasive Aedes mosquitoes countywide, with the highest populations in Santa Ana neighborhoods.

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Invasive mosquito population up 330 percent in Orange County

From ABC7 News
September 19, 2017

The Orange County Mosquito and Vector Control district announced a sharp spike in the presence of the invasive Aedes mosquito in Orange County.

The mosquito species Aedes aegypti (yellow fever mosquito) and Aedes albopictus (Asian tiger mosquito) are not native to the county and are capable of transmitting debilitating viruses including Dengue, chikungunya, yellow fever and Zika.

While these viruses are not currently transmitted locally, transmission could begin if someone infected abroad returns to Orange County and is bitten by the invasive mosquito.

Vector control officials are urging residents to take the necessary precautions to reduce mosquito breeding and to avoid bites from these aggressive day-biting mosquitoes.

Two of the neighborhoods hit hardest are in Fullerton and Santa Ana. Warning signs are up in Raul Ramos’ neighborhood and now he knows to take them seriously.

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Health officials launch door-to-door campaign against West Nile Virus in Los Feliz area

From The Eastsider
September 19, 2017

Officials will be going door-to-door in the Los Feliz-Glendale area on Wednesday, Sept. 20 to warn residents about the risks posed by the potentially deadly West Nile Virus after the area emerged as a hotspot for the mosquito-borne disease.

The Greater Los Angeles County Vector Control District, the public health agency charged with fighting mosquito-borne illnesses, is taking extra precautionary steps after about a dozen human cases of West Nile virus have been detected in the Glendale-Los Feliz area since the beginning of the year, according to county health statistics. That represents nearly 15% of the 81 human cases reported so far in the county.

“Residents in Glendale, Los Feliz, Atwater Village, and Elysian Valley are at higher risk of getting sick from mosquitoes carrying West Nile Virus,” according to a district press release. “Test results to date indicate a significant increase in WNV infection in Culex mosquitoes from these communities even though mosquito numbers in these areas are lower than the 5-year average. At this time of year, mosquito bite prevention is most important.”

District employees will be distributing educational materials to residents. In addition, the agency will partner with local officials to urge residents to prevent bites by wearing insect repellent and eliminating standing water sources around their yards and patios.

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Mosquitoes take a harmful bite out of Tulare County

From Visalia Times-Delta
September 14, 2017

As the weather cools down the number of mosquitoes are going up. And so is the number of mosquitoes testing positive for West Nile Virus.

Climate, as well as the number of birds and mosquitoes, are factors that influence the virus. It is transmitted to humans and animals by a mosquito bite. 

As of Sept. 1, California Department of Public Health reported 87 human cases of West Nile Virus from 13 counties across the state — including Tulare County. Additionally, 239 dead birds collected from 30 counties and 2,284 mosquito samples from 24 counties tested positive for the virus this year.

“West Nile virus can cause a deadly infection in humans, and the elderly are particularly susceptible,” said Karen Smith, CDPH director and health officer. “August and September are peak periods of West Nile virus transmission in the state so we urge everyone to take every possible precaution to protect themselves against mosquito bites.”

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Gulf Flood Waters — Breeding Grounds For Mosquitoes, Raising Zika Concerns

September 14, 2017

Hurricane Harvey’s devastating floods, which inundated vast tracks of neighborhoods in August and brought with it the chance of toxic leaks has raised concern recently about another environmental risk: the rise in mosquito-borne illnesses such as Zika and West Nile. Southern U.S. locations are still dealing with lingering flooding and in an effort to be proactive, the Federal Environmental Management Agency says it plans to start spraying insecticide over the Houston area. It also has its eye on South Florida, which is already considered a natural breeding area for mosquitoes.

Many aerial sprays contain an organophosphate insecticide, which the Centers for Disease Control says is safe to use in populated areas. While FEMA and Texas Health and Human Services haven’t published what insecticide it will be aerial spraying, organophosphates are often the treatment of choice because of their low toxicity to humans.

But they are a problem for bees and by extension, for honey producers, which Houston’s surrounding countryside does support.

And widespread spraying for mosquitoes isn’t necessarily a simple answer for eradicating diseases like Zika, West Nile and dengue, researchers point out. It doesn’t stop the mosquito from breeding the next year or in the years following and the program costs millions of dollars to maintain (Many parts of Florida have maintained spray regimens for decades, unable to block the returning spread of West Nile and other diseases.)

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First Indication of West Nile virus in Shasta County

September 8, 2017

REDDING, Calif. – The first indication of West Nile virus (WNv) for 2017 has been reported in Shasta County in a positive dead bird collected in the Redding area.

Peter Bonkrude, district manager of the Shasta Mosquito and Vector Control District (SMVCD), stated, “The first WNv positive indicator is often identified in Shasta County during the warm summer months. The risk for human infection builds through the season and peaks in August and September. It is important that everyone take the necessary precautions to protect themselves from mosquito bites; it only takes one.”

SMVCD officials urge residents to take precautions by following the “4 Ds of protection”:

  • Drain any standing water that may produce mosquitoes, including flower pots, old tires, and buckets. Some species of mosquitoes can lay their eggs in very small sources of water, like a bottle cap.
  • Defend yourself and your home by using effective insect repellent, dressing protectively when outside and making sure screens on doors and windows are in good condition.
  • Dusk or dawn, avoid outside activities.
  • Dress in long sleeves and pants when mosquitos are active.

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Aggressive yellowjackets breaking records in much of Bay Area

From The East Bay Times
September 7, 2017

Aggressive yellowjacket populations are booming this year in the Bay Area as reports of complaints about nests hit records in some areas.

Winter rains produced plenty of insects to eat, which helped wasp nests thrive, insect experts say. Hot September weather  — like the Labor Day heat wave — spurred the insects to hunt more aggressively for food, increasing the opportunities for human encounters of a painful kind.

Vector control districts in Santa Clara and Alameda reported an unusually high number of public calls about yellowjackets, while Contra Costa is on pace to break its all-time high for yellowjacket service request of 972 set in 1999.

Public calls for help with yellowjackets have increased 83 percent in Contra Costa County so far this year. The vector district received 858 calls through Labor Day this year, up from 469 at the same time last year and more than the 744 calls during all of 2016, the district reported.

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Infectious Mosquitoes Are Turning Up in New Regions

From The New York Times
September 7, 2017

A mounting number of citations on a popular disease-tracking website suggests that mosquitoes may be moving into new ecological niches with greater frequency.

The website, ProMED mail, has carried more than a dozen such reports since June, all involving mosquito species known to transmit human diseases.

Most reports have concerned the United States, where, for example, Aedes aegypti — the yellow fever mosquito, which also spreads Zika, dengue and chikungunya — has been turning up in counties in California and Nevada where it had never, or only rarely, been seen.

Other reports have noted mosquito species found for the first time on certain South Pacific islands, or in parts of Europe where harsh winters previously kept them at bay.

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Press Release: Hot Weather Expected To Increase Spread Of West Nile Virus

From San Joaquin County MVCD
August 31, 2017

(STOCKTON, CA) – The extended hot weather is expected to result in a population increase of mosquitoes. This increase can elevate people’s risk of contracting West Nile virus (WNV). “Mosquitoes develop quickly in hot weather and if they carry WNV, the virus amplifies faster in their bodies”, said Aaron Devencenzi, Public Information Officer with San Joaquin County Mosquito & Vector Control District (District). “Using EPA registered repellents containing DEET, Picaridin, IR3535, or Oil of Lemon Eucalyptus are recommended to prevent mosquito bites and reduce the risk of mosquito-borne disease”, said Devencenzi.

West Nile virus is active throughout San Joaquin County and many parts of California. The District is actively trapping, testing, and spraying for mosquitoes. Eliminating standing water and using mosquitofish in water troughs, neglected pools, and water features are recommended to reduce mosquitoes around homes and properties.

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San Bernardino County reports first West Nile Virus death for 2017

From San Bernardino Sun
August 31, 2017

SAN BERNARDINO >> San Bernardino County Public Health officials announced Thursday the first West Nile Virus death of the 2017 season.

The victim was described as an elderly western San Bernardino County male resident with serious health problems.

So far, there have been eight confirmed cases in San Bernardino County this year, up from six for the entire 2016 season. Two county residents died last year from the virus which is transmitted by mosquitoes, the county health department said, in a statement.

The San Bernardino County death was the third in California this season.

As of an August 25 update, the California Department of Public Health website reports 59 cases statewide, including 27 in Los Angeles County.

“The family has my sincerest condolences with the loss of their family member,” said San Bernardino County Health Officer Dr. Maxwell Ohikhuare. “West Nile Virus can cause a deadly infection in humans, and I urge residents to take precautions and protect themselves against mosquito bites.”

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West Nile Virus Infections Spike In the San Fernando Valley

From Northridge Patch
August 17, 2017

WOODLAND HILLS, CA — Almost half of the 22 people from Los Angeles County who tested positive for West Nile virus so far this year are from the San Fernando Valley, a hot spot where the disease appears to be spreading this season, according to public health and vector control officials.

Officials with the Greater Los Angeles County Vector Control District this week reported a spike in West Nile virus activity, saying they found 49 infected mosquito samples in the region they serve in the last week alone, the Los Angeles Daily news reported. Statewide, Los Angeles County reported the highest number of people infected so far.

“San Fernando Valley is of heightened concern for us this year,” Susanne Kluh, the vector control district’s scientific-technical services director, said in a statement cited by the newspaper.

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Press Release: First Detection of St. Louis Encephalitis Virus in Merced County

August 17, 2017

MERCED, CA– The Merced County Mosquito Abatement District received confirmation that one sentinel chicken from Merced County tested positive for St. Louis Encephalitis Virus (SLEV). SLEV is related to West Nile Virus (WNV) and is transmitted via the bite of Culex mosquitoes, the same mosquitoes that transmit WNV.

Like WNV, most people who become infected with SLEV will never feel sick. People who do feel sick may have mild flulike symptoms; a small number of people will exhibit symptoms that include: headache, confusion, disorientation, and dizziness. Seizures, paralysis, coma, and sometimes death may occur. People who are older and those with weakened immune systems are more likely to develop the severe symptoms. There is no specific treatment for SLEV.

“The sentinel chicken sample that tested positive for SLEV is the first detection of the virus in Merced County in over 40 years”, according to General Manager Rhiannon Jones of Merced County Mosquito Abatement District. “People need to continue to take precautions by protecting themselves and their families from mosquito bites.”

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First human case of West Nile virus this year found in Northern California

From The Sacramento Bee
August 15, 2017

The first human case this year of West Nile virus in Northern California was reported by Butte County health officials Tuesday.

The virus was identified by a blood donation center while it was performing regular screening on blood samples Friday. The donated blood was discarded, and the person in whose blood the virus was found has been notified, said Lisa Almaguer, a Butte County Public Health Department spokeswoman.

Almaguer said she could not disclose the location of the blood donation center or the city where the human case was found. Statewide, 22 cases of West Nile virus have been reported this year, mostly in Kern, Kings, Los Angeles and San Bernardino counties.

The Butte County Mosquito and Vector Control District said it is not notified of the locations of human cases until people show symptoms, District Manager Matt Ball said.

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Mosquitoes carrying West Nile virus on the rise in Elk Grove

From The Sacramento Bee
August 14, 2017

Mosquitoes carrying West Nile virus have increased in the Elk Grove area, and authorities are boosting efforts to control their spread, the Sacramento-Yolo Mosquito and Vector Control District said Monday.

Most mosquitoes testing positive for the virus were trapped south of Elk Grove, between Interstate 5 and Highway 99 and between Laguna Boulevard and Twin Cities Road, district manager Gary Goodman said in a statement.

Parks in the zone are being fogged, and any areas of standing water that might be breeding grounds for mosquitoes are being treated, said district spokeswoman Luz Robles.

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CDC Supports UC Researchers in Fighting Vector-Borne Diseases

By Trina Wood on August 10, 2017, in Human & Animal Health

This week, the U.S. Centers for Disease Control and Prevention announced a bold step to enhance public-health preparedness for diseases transmitted by mosquitoes and ticks in the nation’s southwest. With an $8 million grant from the CDC, University of California, Davis and Riverside researchers will launch the Pacific Southwest Regional Center of Excellence in Vector-Borne Diseases later this month.

“The southwestern U.S. is facing many new challenges in recent years from invasive mosquitoes and emerging pathogens, such as Zika virus, and we urgently need better options for their control,” said UC Davis epidemiologist and center Co-Director Chris Barker. “Funding for this center will enable important research to optimize the tools we have and to look for new ways forward, while training the next generation of public-health scientists.”

Drawing on just one area of science is not going to be sufficient for addressing the challenges presented by vector-borne diseases, which is the strength of the collaboration between the two UC campuses. Both are top-tier research and teaching institutions with leading experts in vector-borne diseases, including entomologists, epidemiologists, virologists and computer scientists who train a diverse group of scholars interested in public health.

According to entomologist and center Co-Director William Walton of UC Riverside, “this Center of Excellence will bring together researchers using the latest cutting edge approaches in the laboratory and field, with practitioners protecting public health to develop a community of practice and provide new technologies to prevent the occurrence of vector-borne diseases.”

The center’s funding begins later this month and continues through the end of 2021. The center has three specific goals:

  • Conduct applied research to develop and test effective prevention and control tools to anticipate and respond to vector-borne disease outbreaks;
  • Train vector biologists, entomologists, and physicians in the knowledge and skills required to address vector-borne disease concerns; and
  • Strengthen and expand existing collaboration among academic communities and public health organizations at federal, state and local levels.

UC Davis and UC Riverside already have strong collaborations with the California Department of Public Health and Mosquito and Vector Control Association of California, who will be critical partners in the center.

“The CDC’s support will enable us to build on these partnerships to ensure that our region of the U.S. will be ready to respond to future threats from vector-borne diseases,” Barker said.

Mosquito district goes from scandal to praise

From the San Mateo Daily Journal
August 7, 2017

Countywide agency recently commended for fiscal management, transparency

From an employee embezzlement scandal to receiving commendations for accountability practices, a little-known special district charged with public health has made significant strides over the last five years.

There hasn’t been much media buzz around the San Mateo County Mosquito and Vector Control District in recent times, and that’s a good thing. In the years since two former employees were caught embezzling nearly half a million dollars, officials now overseeing the district have tightened the reins on the agency responsible for protecting against vector-borne diseases. 

The mosquito district was recently praised in a San Mateo County Civil Grand Jury report that investigated local special districts’ transparency practices. Its accomplishments include being awarded the District Transparency Certificate of Excellence and the District Distinction Designation from the California Special District Leadership Foundation this year. 

“The public’s trust in us is a first priority, we’re always looking for ways to be transparent and accountable, because ultimately we work for the citizens of this county,” said mosquito district spokeswoman Megan Sebay.

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A deadly virus returns to Stanislaus County. Why it’s back and how you can avoid it.

From The Modesto Bee
August 7, 2017

A mosquito sample in Stanislaus County tested positive for the St. Louis encephalitis virus, which is capable of causing a potentially deadly illness.

The mosquitoes infected with St. Louis encephalitis were southwest of Modesto in the Grayson area.

The St. Louis variety is similar to the West Nile virus and is carried by the same kind of mosquitoes. Like a West Nile infection, a person bitten by an infected mosquito may come down with encephalitis, or inflammation of the brain, with headache, dizziness, confusion, seizures or paralysis.

Most people infected won’t feel sick but some will have mild flu-like symptoms, health officials said. Older people and those with weakened immune systems are more susceptible to getting the serious illness. No county residents are known to have come down with the St. Louis illness thus far.

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UC Zika research aims to ‘collapse’ mosquito populations

From The Sacramento Bee
July 31, 2017

Zika, dengue fever and other mosquito-born illnesses have surged to public attention in recent years, with Zika afflicting thousands of people across the Americas. The Zika outbreak that began in 2015 resulted in 1,835 babies born in Brazil with abnormal brain development or problems with their central nervous systems, according to the World Health Organization. Worldwide, another 3.2 million cases of dengue fever, which causes high fever and vomiting, were reported in 2016, according to the WHO.

University of California researchers are tackling the problem by working to develop genetic defenses against mosquito-borne diseases. The team, led by UC Riverside researcher Omar Akbari, recently received a four-year grant from the federal Defense Advanced Research Projects Agency totaling $14.9 million.

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Pregnant Women Urged to Avoid Going to Areas with Zika Risk

July 28, 2017

SACRAMENTO – The California Department of Public Health (CDPH) advises pregnant women, and men and women of childbearing age, not to go to areas with Zika. If they must go to places with known transmission of the Zika virus, CDPH recommends they protect themselves against sexual transmission of Zika and take steps to prevent mosquito bites. Pregnant couples in which one or both partners were in an area with Zika should use condoms every time they have sex, or not have sex during the pregnancy in order to reduce the risk of transmitting Zika to the fetus.
“Whether you work in a location with Zika, visit family who live in places with Zika or travel for leisure to places with Zika, you need to protect yourself,” said CDPH Director and State Health Officer Dr. Karen Smith. “Anyone living in or traveling to areas with ongoing Zika activity may be at risk for infection. It is very important to protect yourself, and if you are pregnant, protect your developing baby from the serious birth defects that can result from Zika infection.”

Mosquito samples in Inyo test positive West Nile Virus

From Sierra Wave Media
July 26, 2017

Inyo County press release

The Owens Valley Mosquito Abatement Program (OVMAP) confirmed Tuesday that some mosquito samples trapped last week tested positive for West Nile Virus.

This is the first occurrence of West Nile Virus in Inyo County since 2011. Prior to that, West Nile Virus had been detected periodically in the Owens Valley after first being discovered in our area in 2004. During that period, no human infections were reported, but 3 horses died after being infected with West Nile Virus.

The three positive samples in Inyo County come during the same week that 214 samples were positive for the disease statewide.

“For every 100 people who are bitten by a West Nile Virus-carrying mosquito, only 20 are risk of contracting West Nile Virus, and of those, fewer than 1% are likely to experience life-threatening reactions” according to Inyo County Health Officer, Dr. James Richardson. Nevertheless, the public is urged to take precautions discussed below.

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Aggressive, stinging colonies of wasps out early this year in Sacramento County

From The Sacramento Bee
July 24, 2017

Yellowjacket infestations are hitting Sacramento County early this year, prompting specialists to eradicate the sometime aggressive insects whose sting can sometime kill.

The Sacramento-Yolo Mosquito & Vector Control District has received numerous calls from residents battling yellowjacket nests on their property. The yellowjacket population problem usually shows itself in late summer or fall.

“It’s definitely early to see yellowjackets now,” said Gary Goodman, district manager.

The district has recently received calls from Rancho Cordova and Folsom, but the biggest problem has come from Herald, a rural community in southeastern Sacramento County.

“We recently treated nearly 90 yellowjacket nests on a five-acre property near the eucalyptus groves,” said Goodman. “When you consider that each nest can have hundreds to thousands of yellowjackets, this can quickly become a threat to residents.”

County residents may call the district if they need help in removing nests. If a colony is disturbed, the wasps can become persistent and pugnacious, increasing the risk of stings.

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Mosquito pool tests positive for West Nile virus in Butte County

July 17, 2017

PALERMO, Calif. – According to the Butte County Mosquito and Vector Control District, a mosquito pool in an area of north Honcut south Palermo has tested positive with the West Nile Virus. 

Officials said with increasing mosquito populations and the detection of WNV within Butte County, the Butte County Mosquito and Vector Control District urges residents to take all precautions necessary to drain any and all un-needed standing water, report any suspected mosquito-breeding sites to the District, and protect themselves from the bites of mosquitoes. 

This is the first positive indicator of WNV in the county for 2017. WNV is active throughout the State of California. WNV has been identified in Butte County every year since its arrival in 2004. Since 2004, 229 residents have been infected with the virus, eight of which lost their lives. 

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Mosquito batch infected with West Nile virus found in Costa Mesa

By LOUIS CASIANO JR. | Orange County Register
July 10, 2017

A batch of 22 mosquitoes infected with the West Nile Virus was discovered late last month in Costa Mesa’s Fairview Park, the city said in a statement.

The mosquitoes were found June 27 by Orange County Mosquito & Vector Control District crews in a drainage ditch at the park’s south end during an inspection of mosquito traps, said Robert Cummings, laboratory director for the control district.

“We are definitely seeing more activity,” Cummings said, adding that about seven infected mosquito batches have been found throughout the county this year.

The area around the traps was treated and is being closely monitored, said Costa Mesa spokesman Tony Dodero.

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NASA Citizen Science App Tackles Mosquito-Borne Disease

June 28, 2017

In many parts of the world, mosquitoes are more than just a summertime nuisance. They spread diseases that kill nearly 2.7 million people a year. Now citizen scientists can use a NASA app to help those working to understand and reduce mosquito-borne diseases.

NASA has introduced the Mosquito Habitat Mapper as part of its GLOBE Observer app available for iPhone and Android. The app includes training, making it easy for anyone to use.

The Mosquito Habitat Mapper guides users through the process of identifying and eliminating mosquito breeding sites. It also gives citizen scientists the option to identify the mosquito species to determine whether it could transmit Zika, dengue fever, yellow fever, chikungunya, and other diseases.

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California Zika By The Numbers


This graphic details the Zika virus infections among California residents from 2015 through June 30, 2017. All cases on record have been among people who were infected while traveling to areas with ongoing Zika transmission, through sexual contact with an infected traveler or through maternal-fetal transmission. No direct transmission from mosquitoes to people has been documented in California. Birth defects have been detected in seven infants infected with Zika before, during or shortly after birth.

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Zika 101 (Vector Control) Rap

A rap video with simple steps for personal protection against Aedes aegypti and Aedes albopictus, the two known mosquito vectors of Zika virus. Prevent Zika by avoiding mosquito bites and taking actions to limit mosquitoes on your property. The mosquitoes that spread Zika develop exclusively in small containers commonly found holding water around the yard. 

Giant Inflatable Mosquito Makes an Appearance to Increase Public Awareness about Invasive Mosquitoes

June 26, 2017

National Mosquito Control Awareness Week is a Reminder to Orange County Residents to Protect Themselves

Garden Grove, CA. There is a new giant inflatable mosquito in town. The Orange County Mosquito and Vector Control District (OCMVCD) is introducing a giant black-and-white inflatable mosquito, depicting the two recently established invasive species of mosquitoes, for National Mosquito Control Awareness Week (June 25 – July 1), to raise awareness and educate residents about the threats mosquitoes pose in Orange County, and throughout the nation. The 13-foot mosquito will be displayed for the first time in public on Friday, June 30th at 4 PM on Historic Main Street (12891 Main St.) in the city of Garden Grove.   

“This giant inflatable mosquito is a fun way to educate Orange County residents about a not-so-fun fact: we now have these aggressive day-biting invasive mosquitoes that can make people sick and will change our quality of life in Orange County,” said Mary-Joy Coburn, Public Affairs Coordinator. “When a member of the public enters the booth, they learn facts about mosquitoes, how to eliminate breeding sources, and how to protect themselves from mosquito bites and mosquito-borne illnesses.”

Click here to read the full press release.

Record Rainfalls and Warm Temperatures Could Mean an Explosion of Mosquitoes

National Mosquito Control Awareness Week is a Reminder to Californians to Protect Themselves 

SACRAMENTO, June 22, 2017 – While California’s wettest winter in 122 years ended the state’s historic drought, the surge in rainfall could contribute to another threat: an active mosquito season with the potential for increased mosquito-borne virus transmission to people.

Heavy rains over the past six months have produced new sources of standing water throughout the state. As the weather heats up, these sources become ideal breeding grounds for mosquitoes which could result in tens of thousands of potential virus transmitters, posing a health risk to Californians.

Mosquitoes in California actively transmit West Nile virus and Saint Louis encephalitis each year, and invasive mosquitoes detected in the state have the potential to transmit even more viruses such chikungunya, dengue, yellow fever, and Zika.

Click here to read the full press release.

Updated CDC map shows 21% increase in US counties reporting mosquito that transmits Zika

Last year, with the Western Hemisphere in the grip of a surprising Zika virus epidemic, CDC researchers used a survey to compile a list of U.S. counties where the mosquito at the heart of the epidemic, Aedes aegypti, had been documented over the past 21 years. They also documented counties that reported finding another mosquito, A. albopictus, known to transmit chikungunya and dengue viruses. The researchers said their data could be used to guide surveillance and mosquito control efforts across the country.

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California’s wet winter could lead to an early mosquito season and increased virus transmission

Mosquito Awareness Week educates California residents on preventing mosquito-borne viruses

SACRAMENTO, APRIL 13, 2017 – As California’s extremely wet winter comes to a close, mosquito experts throughout the state are ramping up for what will most likely be an early and active mosquito season. While the heavy rains were good for the state’s historic drought, they also produce new sources of standing water, the ideal breeding grounds for mosquitoes.

Mosquitoes and warm weather go hand in hand. Spring temperatures will further determine how early and aggressive the mosquito season will be.

With potentially the perfect storm of conditions for mosquito activity, Californians need to be aware of the serious risks mosquitoes present to their health including West Nile, Saint Louis encephalitis, and potentially dengue, chikungunya, and Zika viruses.

Click here to read the full press release.