West Nile virus in horses, humans, dogs and cats

West Nile Virus has spread throughout the United States since its discovery in New York City in 1939, when humans and horses were found to be infected after transmission from infected mosquitoes. This year, the incidence of human infections has soared, presumably due to increases in mosquito populations.

As mentioned, horses are the most susceptible animal. However, whereas humans can be exposed by other routes such as blood transfusions, organ transplants, breastfeeding, and even during pregnancy from mother to baby, equine exposure is thought to be exclusively through the bite of an infected mosquito. Studies have not ruled out ticks as a vector, and they are thought to harbor viruses throughout colder months of the year, but they’ve not been proven to be infective by biting. Read More…