Mosquito-Borne Diseases

Mosquitoes are arguably the most medically important group of insects. In addition to causing severe annoyance and allergic reaction, mosquitoes found in California are capable of spreading many diseases to humans and animals including:

May contain: word, text, label, poster, advertisement, paper, brochure, flyer, and alphabet

Malaria
Yellow fever
Dengue
Chikungunya
Zika
Canine heartworm
West Nile virus
Variety of other encephalitis viruses

Historically, California has experience local transmission of malaria, western equine encephalomyelitis (WEE), St.Louis encephalitis (SLE), California encephalitis viruses, canine heartworm, and West Nile virus (WNV). Canine heartworm and West Nile virus continue to have frequent local transmission in California with West Nile virus human cases numbering in the hundreds every year. However, with increased global travel, the potential for the introduction or reintroduction of many mosquito-borne diseases into California exists.

For more information on any of these diseases, visit our Links page.

13_240124_west_nile_lifecycle_birds_plainlanguage_508.pdf

West Nile Virus

West Nile virus entered California in 2003 and Alameda County in 2004. Since its introduction, activity has been detected every year. West Nile virus is a potentially serious disease and proper precautions should be taken to prevent infection.

Zika Virus

Zika virus was first identified 1947 and is named after the Zika Forest in Uganda. The first human cases were documented in 1952. Since it’s discovery, the virus has been found in both mosquitoes and humans in Africa, the Pacific Islands, Southeast Asia, and the Americas.

West Nile Virus Activity

See a map of reported West Nile activity, a table with statistics for this year, and more.

May contain: electronics, computer hardware, computer, keyboard, computer keyboard, hardware, person, human, and hand

Website Accessibility Statement