Tag Archives: west nile virus

Eastvale Man Among First West Nile Virus Cases in 2018

Staff Reports

Eastvale – A 74-year-old Riverside woman and 50-year-old Eastvale man are the first confirmed human cases of West Nile Virus in Riverside County this year, said Dr. Cameron Kaiser, county public health officer. They are also one of the first confirmed human cases in California this year.

The illness was confirmed this week based on test results and other clinical information. Both patients required hospitalization, thankfully both are expected to recover. There are no indications the two cases are related.

The virus is transmitted to humans and animals through a mosquito bite. Mosquitoes become infected when they feed on infected birds. Health officials emphasized that the risk of serious illness to humans is low. Most individuals who are infected with the virus will not experience any illness. Elderly individuals and those with compromised immune systems are at greatest risk for serious illness.

“While West Nile is rarely life-threatening, it can be occasionally serious,” Kaiser said. “Unlike the common cold which is easily transmitted, the West Nile virus can only be spread by mosquito bites, and there are easy steps to take to reduce your risk of getting bitten.”

Here are some ways to protect yourself:

  • Avoid spending time outside when mosquitoes are most active, especially at dawn and dusk, and wear long pants, long-sleeved shirts and other protective clothing outside.
  • Apply EPA-registered insect repellent that contains DEET.
  • Make sure doors and windows have tight-fitting screens. Repair or replace screens that have tears or holes.
  • Eliminate all sources of standing water on your property, such as old tires, buckets, flowerpots and toys that can support mosquito breeding.-
  • Empty and scrub the water sources. Some mosquitoes can even breed in the amount of water that fits in a bottle cap.

There were 33 human cases reported during 2017 in Riverside County. In 2016, there were 10 confirmed human West Nile Virus cases in the county and there has not been a death from the illness since 2015.

Anyone who becomes ill after exposure to mosquitoes should contact their health care provider.  The Disease Control office can be reached at 951.358.5107 for more information on West Nile Virus.  For more about mosquito abatement, click www.rivcoeh.org/Programs/vector. To download full press release, click here.

To prevent the West Nile Virus spreading in Eastvale, the Northwest Mosquito & Vector Control District performed adult mosquito spray treatments on Friday, June 29, 2018 to lower the mosquito population affecting recreational and residential areas along the Santa Ana River in the City of Eastvale. The spray application was conducted between the hours of 2:00 a.m. to 6:00 a.m. at the following locations:

  • Riverwalk Park and Bike Trail located next to the Santa Ana River
  • Eastvale Community Park
The District treated these areas with Aqua-Reslin (EPA Reg. 432-796), which is approved for use in mosquito control by the US EPA.  They have been working hard to use Integrated Pest Management Practices in these areas, and the majority of their efforts focus on preventing mosquito breeding and killing mosquito larvae before they become flying adults. However, due to elevated trap counts, they have decided that adult mosquito control via truck mounted ground fogger is their best means to control the current mosquito populations in these areas. Signs were posted on June 27, 2018 in the areas that will be sprayed to inform the public of these activities.

Information regarding the treatment will be posted on their website at www.northwestmvcd.org. If there are any questions or concerns please contact the District at 951-340-9792.

West Nile Virus on the Rise in San Bernardino County

Photo courtesy: Google Images

Photo courtesy: Google Images

Staff Reports

Ontario– Local medical centers have reported a rise in West Nile virus exposures in San Bernardino County.

In response, San Bernardino County’s Public Health Department, local vector control agencies and San Bernardino County’s Sheriff Department have joined forces to reduce the risk of exposure.

On Oct. 10, the West Valley Mosquito and Vector Control District (WVMVCD) reported a total of 212 mosquito samples tested positive in the district.

The San Bernardino County Vector Control Program also had 8 positive mosquito samples in basins and channels in Chino, Ontario, and Chino Hills during the past two months.

County entities will remain vigilant with reporting the common breeding areas for mosquitoes, district officials said in a news release. These areas are typically found in stagnant bodies of water and unmaintained pools.
“Aviation helicopters utilize mapping systems that are downloaded with the County’s parcel information,” sheriff officials said. “If an area is observed during the crew’s proactive patrol, the flight officer can obtain the specific address information. Once identified, the information will be forwarded to Vector Control for any enforcement or corrective action.”
The West Valley District’s Board President Glenn Duncan urges residents to maintain vigilant and wear repellents when outdoors at peak biting times, dusk and dawn.

In addition, the West Valley District is distributing repellent wipes and mosquito dunks (a larvicide homeowners can use) to residents in an effort to help them in the fight against mosquito-transmitted diseases.

The West Valley District also provides mosquito fish, a small, guppy-like fish that residents can put in standing, permanent sources of water like ponds, fountains, and water gardens. West Valley Vector Control District consists of the cities of Chino, South Montclair, South Ontario and areas of unincorporated county land, including Chino Hills and the Dairy Preserve. Visit their website for more information, www.wvmvcd.org.

Most people infected with the virus do not become seriously ill, some experience flu-like symptoms and about 1 percent of them can develop serious neurologic illness. People who are 50 and over or who have pre-existing medical conditions such as diabetes or high blood pressure have the greatest risk of developing complications.

Until the weather cools, residents are urged to continue taking precautions, by remembering the three D’s:

  • DEET:Use it as insect repellent.
  • Dawn and dusk:Mosquitoes bite in the early morning and evening.
  • Drain:Eliminate all sources of standing water on your property, because that’s where mosquitoes breed.


Understanding The West Nile Virus Cycle

City of Eastvale


What is the West Nile Virus?

West Nile (WN) virus is a mosquito-borne virus that has been found in parts of Asia, Eastern Europe, Africa, and the Middle East. The virus was first detected in the United States in 1999 (in New York City). The majority of people and animals that are infected with the virus have a mild illness or no symptoms. In rare cases, the virus can cause a more serious inflammation of the brain. The elderly are at a higher risk for disease caused by West Nile virus.
How Do People And Animals Get West Nile Virus?
WN virus is transmitted to people and animals by infected mosquitoes. Only certain species of mosquitoes carry the virus and very few mosquitoes are actually infected. A mosquito first acquires the infection by feeding on a bird with the virus in its blood. The virus lives in the mosquito and is transmitted to a new host in the mosquito’s saliva when the insect bites a person or animal. Humans and horses are incidental hosts for the West Nile virus. The virus is most prevalent from May to October when mosquitoes are most abundant.

What Are The Symptoms Of West Nile Virus In People?

Most people who are infected with WNV have no symptoms whatsoever. However, of those who become ill, symptoms can include fever, headache, nausea, body aches, mild skin rash, or swollen lymph nodes. In a few cases, the disease will progress to encephalitis (inflammation of the brain). The time between the mosquito bite and the onset of the illness, known as the incubation period, ranges from 5-15 days in humans. It is estimated that 1 in 150 people who are infected with WNV will require hospitalization. The elderly are particularly susceptible to clinical illness caused by WNV. There is no specific treatment for infection with WNV, although supportive care is important.

Which Animals Get West Nile Virus?
An infected mosquito can bite any animal, but not all animals will become infected. The disease most often affects birds, but occasionally causes disease in other animals as well.

  • Birds: Wild birds are the animals from which the mosquito vector primarily acquires the virus. Infection has been reported in more than 138 bird species. Although many birds that are infected with WNV will not appear ill, WNV infection can cause serious illness and death in some birds. The most severe illnesses are seen among the corvid birds, which include crows, jays, ravens, and magpies. American crows constitute the majority of the birds reported dead due to WNV.
  • Horses: Horses are also susceptible to WNV. The disease does not seem to be specific to a particular breed or age of horse. Clinical signs of disease consist of central nervous system abnormalities similar to those caused by infection with eastern equine encephalitis (EEE) and western equine encephalitis (WEE). EEE and WEE vaccines are available for horses and are recommended for use in the spring. An equine WNV vaccine is now also available.

West Nile Virus Prevention And Control
To decrease exposure to mosquitoes and the infections they may carry:

  • Avoid outside activity at dawn and dusk during the mosquito season (May to October). This is particularly important for elderly and small children.
  • Wear protective clothing (long pants and long sleeves) and apply insect repellant when outside.
  • Make sure that doors and windows have tight fitting screens. Repair or replace screens that have tears or holes in them.
  • Drain all standing water on private property and stock permanent ponds with fish that eat mosquito larvae.
  • Make sure roof gutters drain properly. Clean clogged gutters in the spring and fall.

What Do I Do If I See A Dead Bird?

If you find a dead bird, particularly a dead crow or other corvid (e.g., jay, magpie, raven), please call the number below promptly. Do not touch the bird.

Dead Bird Surveillance and Contact Information:  West Nile Virus Dead Bird Surveillance Program
Toll Free Telephone: 877-WNV-BIRD (877-968-2473)
Website: http://westnile.ca.gov

Walnut: West Nile Mosquitoes In Walnut



Walnut – On Fri., July 18, the San Gabriel Valley Mosquito and Vector Control District identified two samples of mosquitoes caught in traps at Creekside Park that tested positive for the West Nile Virus (WNV). This is the second finding in San Gabriel Valley over the past several weeks.

According to the SGV Mosquito and Vector Control District – or the Vector Inspectors – WNV is present in the San Gabriel Valley every year. You can help to eradicate this disease from the area by taking an active stance against it through prevention. The Vector Inspectors recommend that you walk around your property and dump out any accumulated water in buckets, barrels, old tires, pots, and other containers. Report any green and stagnant pools, ponds and fountains, as they can breed thousands of mosquitoes weekly; and report all dead birds to www.westnile.ca.gov.

WNV is primarily transmitted from bird to bird by mosquitoes. In some species it is nearly always fatal. The presence of dead birds in a neighborhood is often the first indication of WNV activity.

WNV originated in Africa and was first recognized in the United States in 1999. There is currently no cure; however, most people don’t exhibit any symptoms. Since 2003, there have been more than 4,000 reported infections and 145 deaths in California, according to the Centers for Disease Control (CDC), so the threat should be taken seriously. Symptoms include fever, headaches, body aches, skin rashes and nausea, which can present anywhere from five to 15 days after exposure, and can last several days or months.

Popular Creekside Park is the venue for Walnut’s summer concert and movie series, and there are a number of precautions you can take to prevent infection during this event or any outdoor activity.

Mosquitoes are most active from dusk to dawn, and when enjoying warm summer evenings, be sure to wear loose-fitting long pants and sleeves, and shoes and socks. Treating exposed skin areas and outside clothing with repellents containing DEET, Picaridin, and oils of lemon eucalyptus can also be helpful, according to the CDC.

For more information, visit http://www.westnile.ca.gov.