Outbreak of Locally Acquired Mosquito-Transmitted (Autochthonous) Malaria - Florida and Texas, May-July 2023.

Eight cases of locally acquired, mosquito-transmitted (i.e., autochthonous) Plasmodium vivax malaria, which has not been reported in the United States since 2003, were reported to CDC from state health departments in Florida and Texas during May 18-July 17, 2023. As of August 4, 2023, case surveillance, mosquito surveillance and control activities, and public outreach and education activities continue in both states. U.S. clinicians need to consider a malaria diagnosis in patients with unexplained fever, especially in areas where autochthonous malaria has been recently reported, although the risk for autochthonous malaria in the United States remains very low. Prompt diagnosis and treatment of malaria can prevent severe disease or death and limit ongoing transmission to local Anopheles mosquitoes and other persons. Preventing mosquito bites and controlling mosquitoes at home can prevent mosquitoborne diseases, including malaria. Before traveling internationally to areas with endemic malaria, travelers should consult with a health care provider regarding recommended malaria prevention measures, including potentially taking malaria prophylaxis. Malaria is a nationally notifiable disease; continued reporting of malaria cases to jurisdictional health departments and CDC will also help ensure robust surveillance to detect and prevent autochthonous malaria in the United States.

Acute and Delayed Deaths after West Nile Virus Infection, Texas, USA, 2002-2012.

Infection with West Nile virus (WNV) has a well-characterized acute disease process. However, long-term consequences are less understood. We searched death records for 4,142 residents of Texas, USA, infected with WNV during 2002-2012 and identified 557 (13%) deaths. We analyzed all-cause and cause-specific deaths after WNV infection by calculating standardized mortality ratios and using statewide mortality data. Acute-phase deaths (<90 days after symptom onset) occurred in 289 (7%) of case-patients; of those deaths, 289 (92%) were cases of West Nile neuroinvasive disease (WNND). Convalescent-phase deaths (>90 days after symptom onset) occurred in 268 (7%) of the remaining 3,853 case-patients; 210 (78%) of these deaths occurred in patients with WNND. Convalescent-phase WNND case-patients showed excess deaths from infectious and renal causes; case-patients <60 years of age had increased risk for all-cause death, specifically from renal, infectious, digestive, and circulatory causes. We provide population-level evidence of increased risk for death after WNV infection resulting in WNND.

Typhus Group Rickettsiosis, Texas, USA, 2003-2013.

We characterized the epidemiology of typhus group rickettsiosis in Texas, USA. During 2003-2013, a total of 1,762 cases were reported to the state health department. The number of diagnosed cases and geographic expansion increased over time. Physician awareness is critical to diagnose and effectively treat rickettsial infections.

Rabies postexposure prophylaxis protocol option for unvaccinated domestic animals, Texas: 2010-2019.

OBJECTIVE: To assess data on rabies postexposure prophylaxis (PEP) in domestic animals following Texas' protocol and to describe preexposure and postexposure vaccination failures from 2010 through 2019. ANIMALS: 1,218 unvaccinated animals that received PEP, 925 unvaccinated animals that were euthanatized instead of receiving PEP, and 3 preexposure vaccinated dogs that developed rabies. METHODS: Zoonotic incident reports from 2010 through 2019 were reviewed for information regarding animals with no known rabies vaccination that received PEP or were euthanatized in accordance with state protocol after exposure to a laboratory-confirmed rabid animal; reports were also reviewed for any preexposure and postexposure vaccination failures. The state-required PEP protocol was to immediately vaccinate the animal against rabies, confine the animal for 90 days, and administer booster vaccines during the third and eighth weeks of the confinement period. RESULTS: From 2010 through 2019, 1,218 exposed animals received PEP; 99.8% did not develop rabies. Three failures were recorded, all in animals < 12 weeks of age when PEP was initiated. Additionally, 925 exposed animals were euthanatized instead of receiving PEP. One true preexposure vaccination failure was recorded. CLINICAL RELEVANCE: The Texas PEP protocol was used during the 10-year period. Results indicated that this protocol is a viable option for unvaccinated domestic animals exposed to rabies. Alternative protocols warrant additional consideration.

West Nile virus, Texas, USA, 2012.

During the 2012 West Nile virus outbreak in Texas, USA, 1,868 cases were reported. Male patients, persons >65 years of age, and minorities were at highest risk for neuroinvasive disease. Fifty-three percent of counties reported a case; 48% of case-patients resided in 4 counties around Dallas/Fort Worth. The economic cost was >$47.6 million.