Posts in category: Health Tidings

Situation of Avian Influenza in USA

The first big outbreak of bird flu in the U.S. happened in Pennsylvania from 1983 to 1984, caused by the H5N2 strain, leading to the killing of over 17 million birds. In 2002-2003, a less severe H7N2 outbreak in Virginia led to more safety measures. The worst outbreak was in 2014-2015, when H5N2 and H5N8 strains affected the Midwest, resulting in the loss of over 50 million birds, especially in Iowa and Minnesota. Smaller outbreaks happened from 2016 to 2020, mostly affecting small farms and wild birds, highlighting the need for careful monitoring.

Currently, the U.S. is seeing cases of bird flu linked to the H5N1 strain, which has been spreading worldwide since 2021. This virus reached North America that same year, infecting many wild birds and farmed poultry in several states. Since 2022, many wild birds have tested positive for H5N1, and millions of farmed birds have been killed to stop the virus from spreading. Human cases have been rare, but there is still concern about possible transmission to people. A human case was confirmed in 2022 in Colorado involving a poultry worker who had mild symptoms and fully recovered.

In March 2024, H5N1 was found in U.S. dairy cows for the first time. The first infected herds were in Texas and Kansas, with more cases reported in over ten states. The virus was also found in raw milk and nasal swabs, leading to further investigations. This was the first time H5N1 affected large mammals in the U.S. In April 2024, a human case linked to dairy cattle was confirmed in Texas. The person, a dairy worker, had conjunctivitis and fully recovered.

While the overall risk to human health remains low, the continued spread of H5N1 among birds and now mammals represents a serious threat to the agricultural sector. The potential for viral mutations that could make human transmission more efficient is a key concern for health officials.

Current Human Avian Influenza Cases

As of April 2025, there have been several notable developments in human cases of avian influenza (bird flu), particularly involving the H5N1 subtype.

Mexico’s First Human Fatality: A 3-year-old girl from Coahuila, Mexico, tragically died from H5N1 infection, marking the country’s first confirmed human case. Investigations are ongoing to determine the source of infection, with tests on 38 close contacts returning negative results, indicating no immediate human-to-human transmission.

United States Occupational Exposures: In 2024, the U.S. reported 46 human H5N1 cases across six states, primarily among poultry and dairy workers. Most cases were mild, with no critical illnesses or fatalities. Notably, personal protective equipment (PPE) usage among these workers was found to be suboptimal.

Retrospective Worldwide fatality of H5N1

Indonesia: Indonesia has reported the highest number of human fatalities from avian influenza (H5N1) globally, with over 160 deaths since 2003. Most cases resulted from close contact with infected poultry.

Egypt: Egypt has had the highest number of H5N1 cases in the Middle East and Africa, with over 120 confirmed cases and more than 35 fatalities, primarily affecting rural areas with backyard poultry.

Vietnam: Vietnam has experienced 63 deaths from H5N1 since 2003. Despite aggressive control measures, sporadic outbreaks and fatalities have continued due to poultry exposure.

Cambodia: Cambodia has reported over 30 human cases of H5N1, with a high fatality rate, most of the infected individuals died, often due to delayed treatment in rural areas.

China: China has reported fewer human deaths compared to other countries, but still significant, with over 50 fatalities from H5N1 and other avian influenza strains like H7N9, which emerged in 2013.

Cumulative Global Cases: Since 2003, over 950 human H5N1 infections have been reported across 24 countries, with a case fatality rate of approximately 49%.