As the warm season sets in, the risk for the West Nile virus to manifest becomes higher as mosquito populations increase numbers. The season normally begins in April and lasts until September, but due to warm weather this year, the first cases of the West Nile virus have been reported as early as March 19.

Specialists are trying to prevent the spread of mosquito population, especially in areas that pose the higher risks, such as standing waters or swimming pools left abandoned, by inserting mosquito-fish populations into the water (they are high consumers of mosquito larva).

Authorities with the Mosquito and Vector Control are already on alert, as mosquito colonies have began activity as early as March this year: “It’s just an incredible sight when you go to a back yard pool and the water is literally bubbling with activity,” said Deborah Bass, Contra Costa Mosquito and Vector Control spokeswoman, , the San Jose Mercury News reports

Mosquito-fish are usually used twice a year to lower the number of eggs mosquitos lay in abandoned bodies of water. Draining them could be a solution, as it would eliminate the ideal environment for mosquitos. It only takes a few days for the eggs to turn into mosquitos, the Center for Disease and Control says, which means they are able to reproduce at an alarming rate, increasing the risk for the West Nile virus to spread.

The virus not only affects humans, but also animals living around humans. The infection starts with one bite from an infected mosquito, which for some people could show no symptoms, or could manifest through fever, headache, chills, weakness and drowsiness. Some people experience more dangerous effects, the West Nile meningitis or encephalitis, which includes low levels of consciousness and fatigue.

It can be transmitted from one human to another through blood transfusion, organ transplant, from mother to fetus or through breast feeding. At the same time, the effects of the West Nile virus are more severe for elderly people, while genetics could also expose humans to the disease.