Vector-borne disease

About Vector-borne disease

Vectorborne diseases are diseases that are transmitted from an arthropod (usually a tick or mosquito, etc.) to humans or other animals. Some vectorborne disease agents are maintained primarily through transmission between arthropods and humans (e.g., dengue virus and malaria), while others are maintained between arthropods and animal reservoirs (e.g., Lyme disease and West Nile virus) and humans may become infected incidentally.

Vectorborne Disease and the Environment

Climate is one of many important interacting variables that affect people’s risk for vectorborne diseases in New York City. Warmer winters make it easier for ticks to survive in NYC year-round, while a longer warm season increases the length of time that ticks are active each year. Warming temperatures can lengthen the season in which mosquitoes are out and biting, and accelerate the mosquito life cycle. This can mean more frequent contact between mosquitoes and their hosts, which can facilitate the spread of diseases.

Changing precipitation patterns, with longer periods between rains but heavier rain events, may affect the amount of standing water that mosquitoes have to breed in. Climate change may also alter bird migration patterns or result in changes in deer and small mammal populations that serve as hosts for vectorborne diseases.

Loading data...

Just a moment...


Babesiosis is a rare, sometimes severe or fatal tick-borne disease caused by a parasite that infects red blood cells. Babesiosis is transmitted by the bite of an infected blacklegged tick (the same tick that transmits Lyme disease and anaplasmosis). Most patients acquire this disease while traveling outside NYC. However, there has been an increase in the number of cases with no history of travel to endemic areas, primarily in Staten Island, as well as isolated cases in the Bronx and Queens. Babesiosis can also be transmitted through transfused blood products.

West Nile virus

West Nile virus is transmitted through the bite of infected mosquitoes. While most people who are infected will not go on to develop symptoms, about 20% experience mild or moderate illness and more rarely, neuroinvasive disease which can present as encephalitis or meningitis. Most of the West Nile disease cases detected by the New York City Department of Health and Mental Hygiene represent neuroinvasive disease as these patients are more likely to seek care.