Outbreak of Locally Acquired Mosquito-Transmitted (Autochthonous) Malaria

Florida and Texas, May-July 2023

Dawn Blackburn, BVMS; Michael Drennon, MSPH, MPA; Kelly Broussard, MPH; Andrea M. Morrison, PhD; Danielle Stanek, DVM; Elizabeth Sarney, MA; Christina Ferracci, MPH; Steve Huard; Wade Brennan; John Eaton; Sara Nealeigh; Natalie Barber; Rebecca A. Zimler, PhD; Jeremy N. Adams, PhD; Carina Blackmore, DVM; Manuel Gordillo, MD; Robert Mercado, MD; Harold Vore, MS; Kelly Scanlan; Ian Motie, MD; Leslie Stanfield; Ahmed Farooq, MD; Kimberly Widel, MBA; Kelly Tomson, MS; Nancy Kerr; John Nasir; Marshall Cone, MPH; Connor Rice, MPH; Thomas Larkin; Edwin Hernandez, MD; Jennifer Bencie, MD; Christopher R. Lesser, MS; Max Dersch; Samantha Ramirez-Lachmann, MPH; Marah Clark; Susan Rollo, DVM, PhD; Amira Bashadi, MPH; Ronald Tyler, DVM; Bethany Bolling, PhD; Brent Moore, DVM; Brendan Sullivan, DVM; Eric Fonken, DVM; Raquel Castillo, MPH; Yaziri Gonzalez, MS; Gustavo Olivares; Kimberly E. Mace, PhD; Dean Sayre, MD; Audrey Lenhart, PhD; Alice Sutcliffe, MS; Ellen Dotson, DSc; Claudia Corredor; Emma Rogers, MS; Brian H. Raphael, PhD; Sarah G. H. Sapp, PhD; Yvonne Qvarnstrom, PhD; Alison D. Ridpath, MD; Peter D. McElroy, PhD

Disclosures

Morbidity and Mortality Weekly Report. 2023;72(36):973-978.

Abstract and Introduction

Abstract

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 Anophelesmosquitoes 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.

Table. Epidemiologic and clinical characteristics of locally acquired mosquito-transmitted malaria cases (N = 8) — Florida and Texas, May–July 2023
Characteristic	No. of cases (%)
Age group, yrs
20–39	4 (50)
40–59	3 (38)
60–79	1 (13)
Sex
Men	6 (75)
Women	2 (25)
Signs and symptoms at time of seeking medical attention
Fever	8 (100)
Chills	6 (75)
Abdominal pain	5 (63)
Vomiting	5 (63)
Nausea	4 (50)
Sweats	3 (38)
Diarrhea	3 (38)
Fatigue or weakness	3 (38)
Anorexia	2 (25)
Myalgia	2 (25)
Body ache	1 (13)
Headache	1 (13)
Back pain	1 (13)
Cough	1 (13)
Melena	1 (13)
Shortness of breath	1 (13)
Diagnostic test
Positive rapid diagnostic test result	5 (63)
Positive blood smear test result	8 (100)
Positive PCR test result*	8 (100)

Abbreviation: PCR = polymerase chain reaction.
*Plasmodium vivax was confirmed by CDC through PCR targeting 18S rRNA.

Authors and Disclosures

Dawn Blackburn, BVMS^1,2,*, Michael Drennon, MSPH, MPA^3,*, Kelly Broussard, MPH^4,*, Andrea M. Morrison, PhD⁵, Danielle Stanek, DVM⁵, Elizabeth Sarney, MA³, Christina Ferracci, MPH³, Steve Huard³, Wade Brennan⁶, John Eaton⁶, Sara Nealeigh⁶, Natalie Barber⁶, Rebecca A. Zimler, PhD⁵, Jeremy N. Adams, PhD⁵, Carina Blackmore, DVM⁵, Manuel Gordillo, MD⁷, Robert Mercado, MD⁷, Harold Vore, MS⁷, Kelly Scanlan⁷, Ian Motie, MD⁷, Leslie Stanfield⁸, Ahmed Farooq, MD⁸, Kimberly Widel, MBA⁸, Kelly Tomson, MS⁹, Nancy Kerr⁹, John Nasir⁹, Marshall Cone, MPH¹⁰, Connor Rice, MPH¹¹, Thomas Larkin¹¹, Edwin Hernandez, MD¹¹, Jennifer Bencie, MD¹¹, Christopher R. Lesser, MS¹², Max Dersch¹², Samantha Ramirez-Lachmann, MPH¹², Marah Clark¹³, Susan Rollo, DVM, PhD4; Amira Bashadi, MPH⁴, Ronald Tyler, DVM¹⁴, Bethany Bolling, PhD¹⁵, Brent Moore, DVM¹⁶, Brendan Sullivan, DVM¹⁷, Eric Fonken, DVM⁴, Raquel Castillo, MPH¹⁸, Yaziri Gonzalez, MS¹⁹, Gustavo Olivares¹⁹, Kimberly E. Mace, PhD², Dean Sayre, MD², Audrey Lenhart, PhD², Alice Sutcliffe, MS², Ellen Dotson, DSc², Claudia Corredor², Emma Rogers, MS², Brian H. Raphael, PhD², Sarah G. H. Sapp, PhD², Yvonne Qvarnstrom, PhD², Alison D. Ridpath, MD² and Peter D. McElroy, PhD²

¹Epidemic Intelligence Service, CDC; ²Division of Parasitic Diseases and Malaria, National Center for Emerging and Zoonotic Infectious Diseases, CDC; ³Florida Department of Health in Sarasota County, Sarasota, Florida; ⁴Texas Department of State Health Services Zoonosis Control Branch; ⁵Division of Disease Control and Health Protection, Florida Department of Health; ⁶Sarasota County Mosquito Management, Sarasota, Florida; ⁷Sarasota Memorial Hospital, Sarasota, Florida; ⁸Doctors Hospital, Sarasota, Florida; ⁹Bureau of Public Health Laboratories, Florida Department of Health, Jacksonville, Florida; ¹⁰Bureau of Public Health Laboratories, Florida Department of Health, Tampa, Florida; ¹¹Florida Department of Health in Manatee County, Bradenton, Florida; ¹²Manatee County Mosquito Control District, Palmetto, Florida; ¹³Bureau of Scientific Evaluation and Technical Assistance, Florida Department of Agriculture and Consumer Services; ¹⁴Texas Department of State Health Services Region 11, Harlingen, Texas; ¹⁵Texas Department of State Health Services Laboratory Services Section; ¹⁶Texas Department of State Health Services Region 4/5 North, Tyler, Texas; ¹⁷Texas Department of State Health Services Region 6/5 South, Houston, Texas; ¹⁸Cameron County Public Health, San Benito, Texas; ¹⁹Brownsville Public Health Department, Brownsville, Texas.

Corresponding author
Dawn Blackburn, DBlackburn@cdc.gov.

All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

*These authors contributed equally to this report.