By Ethan Covey
A rancher on a sheep farm in Texas was infected with anthrax following contact with a lamb that unexpectedly died.
The farm is located near the “Anthrax Triangle,” an area of Texas with enzootic anthrax (MMWR Morb Mortal Wkly Rep 2024;73:517-520).
The man, a rancher in his 50s, was initially seen by a general practitioner on Jan. 1, 2024, and was evaluated at an area hospital on Jan. 4 for fever, leukocytosis, a black eschar on his right wrist, and extensive edema and blistered lesions on his right arm. Anthrax was suspected and was confirmed by a polymerase chain reaction test.
The man said that on Dec. 24, 2023, he had butchered a lamb that had died on his ranch. Five people reported exposure to the lamb, including three—the rancher and two others—who consumed the well-cooked meat. None of the other individuals experienced symptoms consistent with anthrax infection. After undergoing treatment, the rancher recovered and was discharged from the hospital.
In early January 2024, two ewes died on the farm. While nasal swabs from the animals tested negative for anthrax, a high level of clinical and epidemiological suspicion for anthrax remained.
“Anthrax cases in animals are expected in this area of Texas,” said Cari A. Beesley, MS, a biologist with the Division of High-Consequence Pathogens and Pathology, National Centers for Emerging and Zoonotic Infectious Diseases, CDC.
However, Dr. Beesley noted that the timing of these animal and human cases was surprising.
“In North America, anthrax outbreaks in animals typically occur in hot, dry summer months, but this outbreak happened in the middle of winter,” she said. “If there is clinical suspicion and a history of animal contact, clinicians should consider anthrax among patients living or working in areas where cases regularly occur in animals. Early treatment can directly impact patient outcomes.”
Dr. Beesley said she hopes future research will address lingering questions, such as what role climate change may play in the seasonality and locations of anthrax cases.
