West Nile Virus Spreading Due to Mosquitoes in Orchards and Vineyards, Experts Warn

Jan. 30, 2013 — Washington State University researchers have linked orchards and vineyards with a greater prevalence of West Nile virus in mosquitoes and the insects' ability to spread the virus to birds, horses and people.

The finding, reported in the latest issue of the journal PLOS ONE, is the most finely scaled look at the interplay between land use and the virus's activity in key hosts. By giving a more detailed description of how the disease moves across the landscape, the study opens the door to management efforts that might bring the disease under control, says David Crowder, a WSU entomologist and the paper's lead author.

Since it was first seen in New York in 1999, West Nile virus has reached across the country and shown few signs of abating. Last year, the U.S. Centers for Disease Control had the highest number of reported cases -- 5,387, including 243 deaths -- since 2003.

Roughly one in five infected people experience a fever, headache, body aches and, in some cases, a skin rash and swollen lymph glands. One in 150 people can get a high fever, headache, neck stiffness, disorientation and neurological problems.

Continued:  http://www.sciencedaily.com/releases/2013/01/130130184318.htm

Officials urge horse owners to vaccinate against West Nile virus

DES MOINES, Iowa (AP) — Iowa agriculture and health officials are warning that mosquitoes are still active in the state and are urging horse owners to have the animals vaccinated against West Nile virus.

The Iowa Department of Agriculture and Land Stewardship and Iowa Department of Public Health said in a joint statement that mosquitoes can carry West Nile virus until the first hard freeze.

Officials say surveillance has shown a larger number of horses have been infected with West Nile virus this year, with more than 20 confirmed cases. Last year, Iowa only had one confirmed case in a horse.

West Nile virus is transmitted through the bite of a mosquito that has picked up the virus from an infected bird. The virus has flu-like symptoms.

http://www.desmoinesregister.com/viewart/20120929/BUSINESS01/120929009/Officials-urge-horse-owners-vaccinate-against-West-Nile-virus

NSF, NIH Award Grants To Study Spread Of Diseases

September 29, 2012

The National Science Foundation (NSF), the National Institutes of Health (NIH), and other US and UK agencies are joining forces to determine whether or not human-induced changes to the environment have played a role in the spread of West Nile virus, Lyme disease and other ailments.

The NSF, the NIH’s Ecology and Evolution of Infectious Diseases (EEID) program, the USDA’s National Institute of Food and Agriculture (NIFA) and the UK’s Biotechnology and Biological Sciences Research Council (BBSRC) are among the organizations studying the possible ecological and biological mechanisms that could be at least partially responsible for the increased number of cases of infectious diseases spreading in both people and animals.

“Threats to human health, food security and ecosystem services are growing, in part due to increases in the spread of diseases,” Sam Scheiner, the NSF’s EEID program director, said in a statement Thursday. “These research projects will provide a new understanding of the causes of that spread and help us control these growing and myriad threats.”

“The interdisciplinary collaborations fostered by the EEID program promote a deeper understanding of how infectious diseases emerge and spread,” added Irene Eckstrand of the NIH’s National Institute of General Medical Sciences. “This knowledge is enormously helpful in developing effective strategies for suppressing the transmission of infectious agents in animal populations and reducing the burden of disease in humans.”

Twelve grants worth a combined $12.7 million have been awarded, and the projects that are being funded will allow scientists to investigate how habitat destruction, invasive species, pollution and other large-scale environmental factors might have contributed to the prevalence of disease-causing viruses, bacterium and parasites in both people and in various animal species, the NSF said in their September 27 statement.

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Continued:  http://www.redorbit.com/news/science/1112703271/infectious-disease-spread-grants-092912/

West Nile virus prompts Texas aerial spraying

Aircraft have begun spraying pesticide over parts of Dallas, Texas to combat an outbreak of mosquito-borne West Nile Virus blamed for 17 deaths this year, authorities said Friday.

The Texas Department of State Health Services said the aircraftcovered 52,000 acres of Dallas County on Thursday night, opening a new front to stop the spread of West Nile Virus.

"Aerial spraying is a safe and very effective tool, but it doesn't take the place of the basic precautions," said David Lakey, the head of the health department.

"We are urging people to continue using insect repellent every time they go outside."

Four more aircraft were to resume spraying later Friday, and residents were cautioned to avoid going outdoors, keep pets inside, cover ornamental fishponds and rinse off homegrown fruits and vegetables.

Throughout the state 465 people have been sickened since the start of the year, putting it on track to have the most cases since the disease first emerged a decade ago, the department said.

The county incorporating Dallas, the ninth-largest city in the United States, has been the hardest hit, prompting the mayor to declare a local state of disaster on Wednesday.

"The city of Dallas is experiencing a widespread outbreak of mosquito-borne West Nile virus that has caused, and appears likely to continue to cause, widespread and severe illness and loss of life," Mayor Michael Rawlings said.

The virus has claimed ten lives in the county so far, local and state health authorities said.

First discovered in Uganda in 1937, the virus is carried by birds and spread to humans by mosquitoes.

Severe symptoms of the virus include high fever, vision loss and paralysis, while milder symptoms range from headaches to skin rashes.

At least 693 cases -- both confirmed and probable -- of the virus have been reported in the United States this year, including 26 deaths, according to the Centers for Disease Control and Prevention.

Texas tops the list in both total cases and fatalities.

http://news.yahoo.com/west-nile-virus-prompts-texas-aerial-spraying-145207403.html?_esi=1

Veterinarians Promote West Nile Vaccine for Horses

The West Nile Virus is impacting the horse population, as well as humans. Horses are vulnerable to the disease, and there have been a handful of reported equine cases this summer.

Veterinarians say there is a way to protect your animal from the virus.

"We have 26,000 head of horses in Denton County, and this is a $55 million annually industry in this county," horse owner Eddie Baggs said.

Baggs is concerned about the impact the virus could have on his animals and the horse industry in Denton County.

Equine veterinarian Matt Lampe said any horse is susceptible; however, like humans, the older horses and horses with weak immune systems are more likely to contract the virus.

"Once they become infected, they get an inflamed spinal column, they lose their coordination, some are unable to rise, and death is not unheard of," Lampe said.

However, Lampe said there is a West Nile vaccine for horses, and it's 94-percent effective.

"We have almost eliminated this disease from the equine populations with the vaccination protocols," Lampe said. "If we are vaccinating your horses, you are very unlikely to see a case. If you are not, you are at the risk as the un-vaccinated people are."

Baggs said there have been four confirmed cases of the virus in horses in the North Texas region this summer. Two of the confirmed cases were in Parker County, and two were in Collin County. He said these low numbers prove the vaccine is effective.

"We are very meticulous about our health program here on the ranch to make sure the horses are taken care of and we take those preventative steps," Baggs said.

http://www.nbcdfw.com/news/local/Veterinarians-Promote-West-Nile-Vaccine-for-Horses-163218586.html 

State Resumes West Nile Virus Testing as Mosquitos Return

State health officials are asking the public to be on the alert for reporting dead birds possibly linked to a West Nile Virus outbreak.

Sunny days and warmer temperatures make way for lots of outdoor activities. It’s also mosquito season, which increases the risk for West Nile virus and the need to avoid mosquito bites.

The state Department of Health has resumed tracking the rare but potentially deadly virus with an online dead bird reporting system that the public can use to alert authorities to potential health hazards. Two such birds were discovered to have died from the virus and found by the residents in King County in 2009.

“It’s important to track West Nile virus so people have the information they need to avoid getting sick,” said Maryanne Guichard, assistant secretary for the state Department of Health’s environmental public health division. “This system helps show where West Nile virus activity is in our state. It also lends a hand to counties where resources are limited.”

Locating and testing dead birds is one way to track West Nile virus since it’s primarily a disease of birds — especially crows, ravens, jays, magpies, and hawks. These birds often die when infected with West Nile virus. The Department of Health asks people to watch for dead birds and report them online or contact their local health agency. Dead bird monitoring is encouraged from May through November.

Continued:  http://mercerisland.patch.com/articles/state-resumes-west-nile-virus-testing-as-mosquitos-return

Dead birds to be accepted earlier for West Nile testing

SPRINGFIELD — All that warm, summerlike weather in March could bring an early start to mosquitoes carrying West Nile virus, state health officials say.

So state labs will begin accepting dead birds for testing two weeks earlier than usual, beginning on Monday, instead of waiting until May 1.

A dead bird can signal West Nile virus is present in the vicinity, because the virus is spread through the bites of mosquitoes feeding on infected birds.

Last year, the virus first turned up in Illinois on June 8 through two birds that tested positive from LaSalle County, and it was present in 19 counties in all, according to the Illinois Department of Public Health.

There were 34 people from Illinois who were sickened by the virus last year, and three who died from it, the health department said.

State labs will test mosquito batches, dead crows, blue jays, robins and other perching birds, as well as samples from sick horses and humans with West Nile-like disease symptoms.

Only 20 percent of people infected with West Nile virus will develop symptoms, which can include nausea, fever, headache and muscle aches, health experts say. But in rare cases, serious illness and death can occur, with people over 50 being at the highest risk.

Jeff Blackford, an environmental health program coordinator at the Champaign-Urbana Public Health District, said the district was able to submit 10 birds for testing from Champaign County last year.

Dead birds subject for testing should appear to have died within the last 48 hours, be free of decomposition, dry eyes and scavenging animals. And they should not appear to have been shot or run over by a vehicle, he said.

Anyone wishing to report a dead bird for investigation should call the environmental health division at 373-7900, he said.

The Ford-Iroquois Health Department is asking people finding dead birds (intact and dead for less than 24 hours) to double-bag them and bring them to the health department offices at 235 N. Taft St., Paxton, or 114 N. Third St., Watseka.

http://www.news-gazette.com/news/health/health-care/2012-04-14/dead-birds-be-accepted-earlier-west-nile-testing.html

West Nile Virus Transmission Linked to Land Use Patterns and 'Super-Spreaders'

ScienceDaily (Oct. 20, 2011) — After its initial appearance in New York in 1999, West Nile virus spread across the United States in just a few years and is now well established throughout North and South America. Both the mosquitoes that transmit it and the birds that are important hosts for the virus are abundant in areas that have been modified by human activities. As a result, transmission of West Nile virus is highest in urbanized and agricultural habitats.

"The virus has had an important impact on human health in the United States partly because it took advantage of species that do well around people," said Marm Kilpatrick, a biologist at the University of California, Santa Cruz, who studies the ecology of infectious diseases.

West Nile virus can infect a wide range of animals, including more than 300 species of birds and 60 species of mosquitoes. It also infects mammals, reptiles, and even amphibians. But researchers have found that in most places only a few key species of bird "hosts" and mosquito "vectors" are important in transmission of the virus.

"We now know that in any given location, only one or two species of mosquitoes play a big role, and only a handful of birds appear to be important in overall transmission rates," said Kilpatrick, who reviewed a decade of research on the ecology and evolution of West Nile virus in a paper published in the October 21 issue of Science.

According to Kilpatrick, the familiar American robin plays a key role in the transmission of West Nile virus across much of North America. It is such an important host species that Kilpatrick calls robins "super-spreaders" of West Nile virus. The reason is not so much the abundance of robins, but rather the feeding patterns of the mosquitoes that transmit the virus. The mosquito species important in transmission seem to prefer robins over other, more abundant species of birds such as house sparrows.

"Robins are more important in transmission than their abundance alone would suggest," Kilpatrick said. "The peculiar feeding habits of the vectors play a really important role in transmission, and this idea applies to many different diseases. It's one of the really interesting things we've learned from the past decade of research on West Nile virus."

Insights gained from research on West Nile virus could help public health officials deal with other introduced diseases in the future. "The spread of disease-causing organisms is likely to only increase in the coming years," said Sam Scheiner, director of the Evolution and Ecology of Infectious Diseases program at the National Science Foundation (NSF). "West Nile virus has provided a test of our ability to respond to such spread. This research shows that predicting disease incidence in humans and other animals is more complex than first imagined, but that greater understanding of such complexities is possible--knowledge that can be applied to the next threat."

The globalization of trade and travel has spread many invasive species, including infectious pathogens like West Nile virus. Although its exact route of entry to New York is unknown, West Nile virus may have arrived in an infected mosquito carried across the Atlantic by an airplane, Kilpatrick said. The virus then adapted quickly to its new environment, evolving a new strain that was transmitted more efficiently by local mosquitoes than the introduced strain. By 2005, the new strain had completely displaced the introduced one throughout North America.

Three species of mosquitoes are key vectors for transmitting West Nile virus in much of North America. Interestingly, these mosquitoes are not among the species that feed frequently on people. They are bird specialists that happen to bite people often enough to cause human infections. "The mosquitoes that bite humans most are actually not as important in transmission of West Nile virus to humans because they rarely bite birds and thus rarely get infected in the first place," Kilpatrick said. "Instead, it's the species that feed mostly on birds and frequently get infected, but occasionally feed on people, that are most important."

Millions of birds have died from West Nile virus infection, with dramatic effects on the populations of some species. Crows, for example, are much less abundant than they were before the virus arrived. The robin population, which had been growing rapidly, has leveled off.

"Robins were on a steady upward trajectory thought to be linked to human land use--they love lawns and agricultural fields," Kilpatrick said. "Crow populations were growing even faster. Now crow populations have crashed downward and robins have leveled off, and we suspect that's due to West Nile virus."

Read more ...

New Threat Closes in On Iconic Galápagos Wildlife

ScienceDaily (Sep. 17, 2011) — Renewed vigilance over the biosecurity of the Galápagos Islands is needed, based on new research on the risk posed by West Nile virus. Scientists from the Zoological Society of London (ZSL), the University of Leeds and the New York State Department of Health, together with the Galápagos National Park Service and University of Guayaquil, have been studying the disease threat posed by Islands' mosquito populations. They have discovered that a species of these biting insects is capable of transmitting West Nile virus, a potentially dangerous disease for the archipelago's unique wildlife.
West Nile virus (WNV) most commonly affects birds, but can infect mammals, including humans, and reptiles. Previous studies of West Nile virus impact in the USA have linked the virus to declines in several bird populations, demonstrating the high risk it poses to the Galápagos' endemic species. The virus recently invaded South America, but has yet to reach the Galápagos.

Recent studies on tourist boats and planes have shown that the mosquito species Culex quinquefasciatus (also known as the Southern house mosquito) is hitching a ride onto the Galápagos on airliners. Culex species are well-known vectors of WNV elsewhere in the world, so their presence on the Islands has caused concern amongst the scientific community.

The ability of mosquitoes to transmit particular disease agents effectively often varies between species, or between populations within species. Therefore to understand the risk posed by C. quinquefasciatus in Galápagos, the research team measured the ability of Galápagos C. quinquefasciatus to pick up and transmit WNV in the lab, under conditions that simulated those in the wild. They found that Galápagos C. quinquefasciatus were indeed effective vectors for the virus.
Prof Andrew Cunningham from ZSL says: "We now know that mosquitoes capable of carrying West Nile virus have a route onto the Galápagos, and once there, the virus could also spread into the local mosquito population. This means there is potential for large impacts on endemic species. There is no doubt that West Nile virus poses a serious threat to the survival of the Galápagos' iconic wildlife."
In order to reduce the chances of West Nile virus reaching the islands, the authors suggest further research to determine the presence of WNV in the mainland Ecuador, plus strict enforcement insect control measures on aircraft and ships moving between the mainland and islands.

Dr Simon Goodman from the University of Leeds says: "Piece by piece we are building up a comprehensive picture of the disease ecology in Galápagos and what could happen if WNV were to reach the islands. Once WNV has been introduced onto the Galápagos, it would be much harder to contain. Therefore the best strategy is to have strict preventive measures to reduce the chance of the disease reaching the islands in the first place."

Lead author PhD student Gillian Eastwood says: "Whilst WNV does not yet exist in Galápagos, it is important to envisage what future disease scenarios could be by looking at how this particular virus would interact within this unique ecosystem. Evaluating the role that mosquitoes could play is therefore vital. This recent part of our work is however only one aspect to understanding potential WNV transmission on the Islands; it remains to see how severely Galapagos wildlife might be affected but all precautions should be taken."

The research is published in the current edition of the American Journal of Tropical Medicine Hygiene.

http://www.sciencedaily.com/releases/2011/09/110916102406.htm