Ward Stone and the West Nile Virus 
Ward Stone and the West Nile Virus
Albany, NY &emdash; Ward Stone, State Wildlife Pathologist, spoke at the August SPB lasagna dinner at the First Presbyterian Church. He began by describing the virus’ one-year journey from Westchester to the Capital District.
In July, 1999, crows seemed to be dying in Suffolk and Westchester. Stone had been pathologist for 31 years, and had never seen this disease before. Stone called the Health Department, and discovered they had no lab to culture the virus. He sent samples to labs in Wisconsin and Ohio which both determined that they had not seen this disease before. Finally, Stone sent a sample to the Center for Disease Control (CDC) in Fort Collins, Colorado who identified the virus as West Nile. The virus is named for where it was first identified in 1937 when the first person died of it in Uganda. This particular strain of West Nile was identified in Israel a year before coming to the US, in 1998.
Crows are very sensitive to West Nile. 100% of the crows which contract West Nile die of it.
How did the virus reach New York? There are only theories. Mosquitoes carry the virus and transmit it from birds to humans and back again. One theory is that an infected mosquito got on a plane to New York. Possibly a mosquito hitched a ride on a ship or tanker. Or, the virus could have come in an infected bird imported into the US. Though the birds are quarantined for seven weeks, it is possible that it came in a bird that only had a very mild illness, and it went unnoticed. Perhaps the virus arrived in a zoo or pet mammal.
1999 was probably not year one for West Nile virus in New York. It has probably been here for a few years.
For young, newborns, elderly, and people with suppressed immune systems, West Nile is a deadly disease. People have been cavalier about the disease because they think that only a few people have died. However, this time of the year means more birds and more mosquitoes, and more mosquitoes more birds mean more West Nile virus.
Eventually, the West Nile virus will extend across the country. It will travel with migrating birds. West Nile virus is killing tens of thousands of birds. Some of the birds killed include the American crow, house sparrow, mallard duck, rough grouse, blue heron, snowy owls, red-tailed hawks, sparrow hawks, belted king fisher, American robin, mocking bird, eastern bird, killdeers, and mourning doves. West Nile has also been found to kill pet birds, such as cockatoos and cockatiels. Stone recommended that people not leave their caged pet birds outside, where they could be bitten by mosquitos. West Nile has been found in big brown bats, the first mammals that have tested positive.
Stone then outlined how the West Nile virus can be controlled. He spoke about reducing places where mosquitoes breed, such as standing water. Larvicides can be used to kill the mosquito larva. The larvacide is specific to the mosquito, and does not harm other types of insect larva.
On spraying, Stone said the health departments are damned if they do and damned if they don’t. Last year, malathion was used, which Stone opposed. This year, Anvil was used. Stone said that spraying can save lives, which is very important. Also, we need to save the birds.
On the positive side, Anvil has little toxicity to mammals. Stone has never seen Anvil kill wild mammals and birds when applied in the recommended amounts. However, we need a safer, more specific pesticide. Anvil kills invertebrates, and Stone said it should never be sprayed near endangered insects such as the Karner Blue. The British are working on a vaccine, and probably the first vaccine we will see will be for horses.
Stone noted that one of the major environmental problems of today is pathogens. He feels that it is very important that we think about ways to stem the tide of these exotic diseases. We need to improve our methods of diagnosis and work together, the wildlife pathologists and human doctors.
published October/November 2000 Newsletter
Last Updated 10/16/00
