CDC Finds Evidence of Recent Avian Influenza Infection in Three Veterinary Practitioners
The results of a serosurvey conducted among 150 bovine veterinary practitioners in mid-September found evidence of recent infection with highly pathogenic avian influenza (HPAI) A(H5) virus in three practitioners, according to a report published last week in CDC’s Morbidity and Mortality Weekly Report (MMWR). None of the practitioners with positive serology results worked with dairy cattle with known or suspected HPAI A(H5) virus infection, though one practitioner reported working with poultry confirmed to be infected with the virus.
Two of the seropositive practitioners cared for cattle in multiple states, including states with known HPAI A(H5) infection among dairy cattle as of September 2024. However, one practitioner with a positive serologic test result reported caring for cattle only in Georgia and South Carolina, two states that had not reported HPAI A(H5) infection in dairy cattle. (According to U.S. Department of Agriculture Animal and Plant Health Inspection Service data that was last updated on Jan. 16, Georgia and South Carolina still have no cases of confirmed HPAI A(H5) virus infection in cattle, and the states have no reported human cases per CDC.)
All three affected practitioners reported wearing gloves or a clothing cover while caring for cattle, but none reported the use of respiratory or eye protection. The three seropositive practitioners did not report any respiratory or influenza-like symptoms, including conjunctivitis, or red, draining, or itching eyes, which CDC describes as “the predominant symptom among recent U.S. cases of avian influenza A(H5) virus infection.”
“Detection of HPAI A(H5) antibodies in persons without reported symptoms suggests that surveillance of symptomatic exposed workers might underestimate human infection,” the MMWR states. “These data highlight the possible benefit of national seroprevalence assessments of recent HPAI A(H5) infection among practitioners at increased risk for exposure, which might help assess occupational risk in states without confirmed HPAI A(H5) virus detections in dairy cattle.”
The CDC report also suggests “continued systematic surveillance of livestock and milk” as part of the nation’s approach to help protect veterinary practitioners and others who work with animals. For further details, read the MMWR.
As of Feb. 19, CDC had confirmed 69 human cases of avian influenza A(H5) and 1 death. The virus is responsible for outbreaks in poultry flocks and an ongoing multi-state outbreak among dairy cattle that was first identified in March 2024. CDC characterizes the current public health risk as low and states that there is currently no evidence for person-to-person H5N1 transmission.
Related: An article published in this month’s issue of The Synergist focuses on ethical considerations around infectious disease response.
