West Nile has been identified in 20 Iowa counties so far this summer according to the state public-health department, which has confirmed just two human cases. Stephen Dinsmore, an avian ecologist at Iowa State University, says since the virus is linked to the death of crows and bluejays, it’s safe to say it also affects a lot of other wild birds in Iowa.
Dinsmore says it’s more widespread than just a few, and while he doesn’t know how susceptible various species of birds may be, “every indication is that it varies.” This month at a wildlife center in Idaho, West Nile Virus was blamed for the deaths of four condor chicks, a species still considered rare and endangered.
Dinsmore says Iowa’s got its own list of wild birds considered at risk or endangered. Around 410 species of birds have been identified in Iowa, and he says perhaps 20 species are considered, between federal and state lists.
In Iowa, endangered birds include the piping plover, least tern and trumpeter swan. Dinsmore says the mosquito-borne virus could also add to the burden of survival for species that are already very low in numbers.
Though the mosquitoes that carry West Nile die off in wintertime, Dinsmore says in the terms of epidemiology, birds in general are a reservoir species where the virus can linger till the next summer season. He says it’s transmitted by mosquitoes that bite a host animal to drink its blood.
Dinsmore says, “There presumably are other species out there that serve as places where the disease can linger undetected.” When it resurfaces, the mosquitoes whose bite carries the virus will infect other living being, including horses, the crows and bluejays in the corvid family of birds, and people of course.
West Nile in Iowa may be following the typical pattern in which it peaks a couple years after being discovered in a new state, and then cases fall off in number. This year Iowa’s confirmed only two human cases, and both those people have recovered from the disease.