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A: Locally-acquired human malaria (Plasmodium falciparum, P. vivax, P. malariae, and P. ovale) had a major impact on the development and economy Florida from 1800 through 1940. For example, in 1919, a 65% human infection rate was reported in Taylor County. The Golden Age of malaria control in Florida occurred between 1930 and 1932, when malaria control stations were established in Pensacola, Tallahassee, and Jacksonville. Florida was reported malaria-free in 1949 after 67 years of local transmission.

Since then, there have been rare reports (1990, 1996, and 2003) of locally-acquired malaria infections in Florida. To re-establish, malaria must first enter Florida in an infected traveler, which actually does happen frequently. From 2010-2021, an average of 812 travel-related human malaria cases were reported in Florida per year. However, less than 1 locally-acquired human malaria case per year was reported during the same period of time. It is the behavior of the vectors (Anopheles quadrimaculatus and An. crucians) that makes re-establishment so difficult. These mosquitoes are most active in the middle of the night. Prior to the mid-20th century, most homes were not air conditioned and window screens were rare, so people were routinely exposed overnight. Today, the adoption of AC, window screens, and a tendency to stay indoors overnight all make the re-establishment of human malaria in Florida highly unlikely.

As of April 24^th, 2022 the surface water conditions in Florida have been consistently wet in the north and dry in the south.

Vector and arboviral surveillance remain one of the most important tools that vector control agencies currently have at their disposal. Arboviral transmission indices (sentinel chickens, positive equines, positive exotics (i.e., emus), positive humans, and positive mosquito pools) provide indicators of local virus transmission, although sometimes not in a timely manner. Monitoring mosquito populations and their age structure provide added information about potential transmission risk. Additional vector control efforts in and around sites where virus transmission is known or suspected of recently occurring provide another potential mechanism to mitigate viral transmission.

Specific operational strategies will be discussed during the 2022 arboviral transmission season depending on where and when vector-borne disease transmission becomes evident in the state of Florida.

Jonathan Day, Professor Emeritus of Medical Entomology from the University of Florida, is a national expert on mosquitoes and other blood-feeding arthropods that transmit diseases to humans, domestic animals, and wildlife. In collaboration with other researchers, Dr. Day has developed an effective system for monitoring and predicting epidemics of mosquito-borne diseases.

Acknowledgments: This analysis would not be possible without the tireless efforts of multiple agencies across Florida. At least 27 Florida agencies collect serum samples from sentinel chickens each week and mail them to the Florida Department of Health Tampa Branch Laboratory for analysis, compilation and reporting. Data are summarized by researchers at the Florida Department of Health in Tallahassee and reported weekly as the Florida Arbovirus Surveillance Report.

Daily updates of the Keetch-Byram Drought Index (KBDI) are produced by the Florida Department of Agriculture and Consumer Services, Forest Service.

All of the graphics used in issues of this Newsletter are designed and developed by Gregory Ross.

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