H5N1 Bird Flu Persists: Low US Outbreaks Continue, Cambodia Sees Spike in Human Cases

Bird Flu Bulletin: Daily H5N1 Update Saturday, July 19, 2025 This is the Bird Flu Bulletin: Daily H5N1 Update, bringing you the latest on the avian influenza situation. Today is Saturday, July 19, 2025. Top stories First, United States animal and human surveillance remains stable with only one new detection in poultry from a game bird farm in Pennsylvania and two detections in dairy cattle in California and Arizona over the past month. The Centers for Disease Control and Prevention emphasizes that outbreaks continue at low levels nationally. Scientists are investigating farm-based transmission routes, with new evidence pointing to flies and an on-farm practice called "milk snatching" as possible contributors to virus spread, in addition to previously suspected causes like movement of infected cattle and shared equipment. The CDC and USDA are maintaining heightened surveillance and biosecurity measures. Second, in Cambodia, the World Health Organization confirmed 11 new human H5N1 cases since January 1, with seven of these occurring in June—an unusually high spike. Among the 27 cases reported in Cambodia since early 2023, about 44 percent have been fatal, and most involve children under 18. The latest WHO assessment reiterates that the risk to the general population remains low, though those working directly with infected poultry are considered at higher risk depending on farm practices and protective measures. Authorities continue public messaging around best practices for backyard poultry owners. Third, the World Organization for Animal Health’s latest update highlights an overall decline in poultry outbreaks worldwide in June, although there is a reported rise in detections among wild birds, especially across Europe. These seasonal patterns, coupled with increased wild bird cases, have prompted calls for ongoing monitoring, particularly as bird migration patterns shift during the summer and fall. Case numbers Compared to yesterday, there have been no new human cases reported in the United States, consistent with the CDC’s last monthly update. Cambodia’s figures stand unchanged, with the most recent spike confirmed in late June by WHO. According to the CDC, H5N1 case updates for both monitored individuals and animals in the US now follow a monthly reporting cadence, making international context particularly important for daily monitoring. New guidance There are no new public health alerts from major agencies in the last 24 hours. The CDC continues to advise healthcare professionals and veterinarians to be alert for influenza-like illness in anyone exposed to birds or dairy cattle, and to follow established protocols in the event of a suspected case. Ongoing recommendations stress the importance of personal protective equipment for farm workers and biosecurity on farms and in backyard flocks. Expert interview Professor Lisa Grant, a virologist specializing in zoonotic diseases, commented today: "The persistence of H5N1 in both wild a This content was created in partnership and with the help of Artificial Intelligence AI.