The West Nile Virus is a viral disease that causes deadly encephalitis in birds, horses and sometimes, humans. A major gathering of microbiologists in July led to a report on this health problem.
“West Nile virus is the most significant exotic mosquito-borne disease that has come to the contiguous United States in the last century,” according to Dr. Lyle Peterson, Director of the Division of Vector-borne Infectious Diseases at the Centers for Disease Control and Prevention. “Outbreaks have proven extremely difficult to predict and control and have been associated with considerable morbidity. The large outbreak in 2012, which caught many by surprise, indicates that West Nile virus will remain a formidable public health challenge for years to come.”
West Nile Virus is spread from mosquito to bird, to mosquito, to bird. People, horses and dogs are all “accidental hosts” or dead end hosts. While people, dogs and horses can all become ill, the virus is not comfortable replicating in those species, so a sick horse can’t give the virus back to mosquitoes. Grackles, tufted titmice and crows are all birds in which the virus can easily replicate and therefore spread to any mosquitoes that bite them.
Most people infected with West Nile Virus will get a mild fatigue with flu-like symptoms. Rarely, people may suffer from the deadly neurologic form of the disease.
Warm weather, coupled with either plenty of rain or very little rain can lead to larger outbreaks of WNV. With plenty of rain, there are plenty of mosquitoes around to spread the disease. With drought conditions, the susceptible bird populations and the mosquito populations all tend to congregate around the same water sources.
It is important to minimize mosquito populations in your yard. Dump standing water containers, like birdbaths, daily. Remove old tires and other containers that might hold water for mosquito breeding. Encourage populations of birds that will eat mosquitoes and also bat colonies. Add mosquito larvae eating fish to ponds.
There is a West Nile Virus Vaccine available for horses. There are also mosquito repellants that can be used for horses that are outdoors much of the time. There is no vaccine for dogs at this time. People and dogs should use mosquito repellants and avoid going outside at times of peak mosquito activity – generally dawn and dusk.