Vector-Borne & Zoonotic Reports

The Maricopa County Department of Public Health (MCDPH), Office of Epidemiology, and the Maricopa County Department of Environmental Services (MCESD), Office of Vector Control, collaborate to educate and protect the residents of Maricopa County against mosquito-borne illness.

Mosquito-Borne Diseases in Maricopa County 2023

Confirmed and Probable Cases & Deaths as of 11/29/2023

Data are updated weekly on Friday.
NOTE: Cases will not be updated on December 8, 2023, and will resume the following week.

Locally Acquired

Disease	Current Year Cases	Current Year Deaths	Cases Same Date Last Year	Deaths Same Date Last Year	2022 Total Number of Cases
St. Louis Encephalitis Virus (SLE)	0	0	13	1	13
Unspecified Flavivirus Group 1 (WNV/SLE)^§	0	0	0	0	0
West Nile Virus (WNV)^*	73	10	42^†	2^†	42^†

*The number of WNV cases currently under review and pending classification is 0. This number is not reflected in the number of current cases above.
^†Ten cases and one death were reported in 2022 but occurred or had incubation periods in 2021.
^§Unspecified Flavivirus indicates an infection that could not be attributed to a single mosquito-borne disease.

Travel-Related*

Disease	Current Year Cases	Cases Same Date Last Year	2022 Total Number of Cases
Chikungunya	0	0	0
Dengue	23	13	13
Zika	0	0	0

*Travel-related cases are those in which residents brought the disease in from other places or passed on the disease during birth as the result of infection acquired during travel.

All data are provisional, based on date reported to Public Health.
Maricopa County weekly counts may vary slightly from state reporting due to differences in data reporting.

Current Year = 2023
Last Year = 2022

West Nile Virus End of Year Reports
The WNV end of year report provides information such as the annual number of WNV cases in Maricopa County, WNV activity by month, WNV rates per city, and number of mosquito pools by month.

Other Mosquito-Related Diseases
Other county reports for mosquito-borne illness are generated on an as needed basis.

Mosquito-Borne Disease End of Year Reports
The end of year report provides information related to all local and travel-acquired mosquito-borne illness cases in Maricopa County. Data includes types/frequency of symptoms, locations of disease transmission, and characteristics of human infections.
End of Year Final Report (PDF)

Mosquito Sampling Statistics
Maricopa County Environmental Services Department (MCDES) Vector Control has an extensive mosquito trapping and testing program that enables staff to identify areas where there is a lot of mosquito activity and to detect mosquito-borne diseases. View the Mosquito-Borne Disease Statistics page for details.

For more data not found here, you also can visit the ADHS Mosquito-Borne Illness page.