Mosquito & Vector-Borne Diseases

Even here in the dry climate of Maricopa County, mosquitoes are a problem. Mosquitoes are small insects that breed in standing water and the female mosquitoes need blood to lay eggs. Sometimes mosquitoes carry germs (e.g., viruses and parasites) that can be spread to a person when the mosquito bites them. Preventing mosquitoes from breeding and avoiding mosquito bites are the best ways to avoid getting these diseases.

To learn more about each mosquito-borne disease, find its name below. 
Mosquito

Mosquito-Borne Diseases in Maricopa County 2019

Confirmed and Probable Cases & Deaths as of 11/28/2019

DiseaseCurrent Year (2019) as of 11/28/2019Last Year (2018) as of 11/28/20182018 Total Number of Cases
LOCAL
Cases
Deaths
Cases
St. Louis Encephalitis (SLE)5
00
West Nile Virus (WNV)157162424
Unspecified Flavivirus (SLE/WNV)†10
01
TRAVEL-RELATED*
Chikungunya
1
0
00
Dengue120
67
Zika00
22
Unspecified Flavivirus (Dengue/Zika)†00
0
0

All data are provisional, based on date reported to Public Health.

Disease Statistic Notes 

* To date, Maricopa County has only experienced travel-related cases of chikungunya, dengue and Zika, meaning that residents brought the disease in from other places or passed on the disease during birth as the result of infection acquired during travel.
† Unspecified Flavivirus indicates an infection that could not be attributed to a single mosquito-borne disease.

Find annual summary numbers of mosquito-borne diseases in Maricopa County, including the number of human deaths attributed to them .

Additional mosquito-borne disease data may be found on the Arizona Department of Health Services' Mosquito-Borne Disease webpage.

DISEASES

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  1. Office of Epidemiology

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    Physical Address
    4041 N Central Avenue
    Phoenix, AZ 85012

    Phone: 602-506-6900
    Fax: 602-372-8935