DEET formulations as high as 30% are recommended for children over two months of age. The CDC also recommends the use of: IR3535, oil of lemon eucalyptus, para-menthane-diol, or 2-undecanone. Protect infants less than two months of age by using a carrier draped with mosquito netting with an elastic edge for a tight fit. When using sunscreen, apply sunscreen first and then repellent. Repellent should be washed off at the end of the day before going to bed. Wear long-sleeve shirts, which should be tucked in, long trousers, socks, and hats to cover exposed skin (although most fabrics do not totally protect against bites). Insect repellents should be applied over top of protective clothing for greater protection. Do not apply insect repellents underneath clothing. Repellents containing permethrin (e.g., Permanone) or other insect repellents may be applied to clothing, shoes, tents, mosquito nets, and other gear. (Permethrin is not suitable for use directly on skin.) Most repellent is generally removed from clothing and gear by a single washing, but permethrin-treated clothing is effective for up to five washings. Most mosquitoes that transmit disease are most active at dawn and in the evening dusk. A notable exception is the Asian tiger mosquito, which is a daytime feeder and is more apt to be found in, or on the periphery of, shaded areas with heavy vegetation. They are now widespread in the United States, and in Florida they have been found in all 67 counties.
There also have been reports of possible transmission of the virus from mother to child during pregnancy or breastfeeding or exposure to the virus in a lab, but these are rare cases and not conclusively confirmed.Recently, the potential for mosquito saliva to affect the course of WNV disease was demonstrated. Mosquitoes inoculate their saliva into the skin while obtaining blood. Mosquito saliva is a pharmacological cocktail of secreted molecules, principally proteins, that can affect vascular constriction, blood coagulation, platelet aggregation, inflammation, and immunity. It clearly alters the immune response in a manner that may be advantageous to a virus. Studies have shown it can specifically modulate the immune response during early virus infection, and mosquito feeding can exacerbate WNV infection, leading to higher viremia and more severe forms of disease. Vertical transmission
Vertical transmission, the transmission of a viral or bacterial disease from the female of the species to her offspring, has been observed in various West Nile virus studies, amongst different species of mosquitoes in both the laboratory and in nature. Mosquito progeny infected vertically in autumn may potentially serve as a mechanism for WNV to overwinter and initiate enzootic horizontal transmission the following spring, although it likely plays little role in transmission in the summer and fall. Risk factors
Risk factors independently associated with developing a clinical infection with WNV include a suppressed immune system and a patient history of organ transplantation.