West Nile Virus Reprise

(This column was first published in the November 6, 2000 Buffalo News.)

    When I first wrote about the West Nile virus in July, this dangerous microbe was only a distant threat. Before last year it had never been encountered in North America, but in 1999 it was identified here as the disease that killed seven of 62 human patients stricken as well as hundreds of birds -- all, however, in New York City.

    Now the 2000 mosquito season has ended and I will review this year's history of the virus. But first I remind readers that this is a sickness that produces for most of those afflicted only flu-like symptoms -- fever, headache and a mild rash -- that persist for just a few days. Unfortunately however, for a small proportion of those who contract the disease encephalitis ensues -- the brain is more severely damaged -- and death can be the end result.

    Unlike the terrible flu that killed millions of the young and middle-aged after World War I, the West Nile virus is a serious problem almost exclusively for the aged. And this year's record bears that out. The sole victim was an 82-year old New Jersey retired welder, a walker whose daily hikes often took him though a local woodlot and near several mosquito-breeding pools. Among the local responses to this death, officials at a nearby high school canceled their marching band's regular evening practices.

    The number of identified human cases of West Nile virus in New York dropped significantly this year. Thankfully there have been only thirteen. Even with the four in New Jersey and one in Connecticut, that represents a 71 percent decrease from 1999.

    But there is less positive news as well. The New York State Health Department has posted a map showing occurrence of this disease in various animals statewide. As the summer progressed I watched this map fill in with reporting counties. Now remarkably only Chemung County has failed to identify any affliction among wildlife species.

    We have not escaped this spread in Western New York. The number of species -- all birds -- identified as carrying the disease by county is: Erie 24; Chautauqua 16; Niagara 5; Cattaraugus 4; Allegany, Wyoming and Orleans 3; and Genesee 2. (It is important to note that those numbers reflect not only the presence of this virus but also the level of investigation of individual county health officers.)

    The list of species that have been found to have West Nile virus statewide is extensive. Among mammals (as well as the 13 men and women) were 13 horses, 14 bats, 3 rabbits, 3 squirrels, 2 cats, 2 raccoons and a chipmunk.

    The bird list is still longer. It includes in addition to 811 crows, lesser numbers of jays; gulls and herons; doves, grouse and pheasants; robins and bluebirds; several hawk species; cormorants and kingfishers; waxwings and starlings. Even our smallest species are represented: several warblers and a hummingbird.

    Until a month ago it was thought that the virus is communicated only through mosquito bites. Now it has been established that it may also be passed on without that intermediate vector, in the case investigated, from one crow to another.

    There is bad news on the mosquito front as well. Originally the disease appeared to be confined to one or two species that occurred only downstate. Now mosquitoes of four different genera carry it, several of the species indigenous to our region.

    Clearly we must adapt to the West Nile virus for the foreseeable future. It will confront us with a challenging question: Will we give up our hard-fought gains in the pesticide wars to address this new enemy?

    Stay tuned.-- Gerry Rising