madárinfluenza

Madárinfluenza, also known as avian influenza, is an infectious disease caused by influenza A viruses that primarily affect bird species. The viral genome is segmented, allowing frequent reassortment and the emergence of new subtypes. The most studied subtypes include H5N1, H7N9, and H9N2, each capable of infecting humans when exposed to infected birds or contaminated environments. Human cases usually arise from close contact with sick or dead poultry, live bird markets, or environments where poultry are held in proximity to humans.

Symptoms in birds often range from mild respiratory distress to sudden death, depending on the virulence of the strain. When transmissible to humans, the disease can present as a flu‑like illness that may progress to severe pneumonia, acute respiratory distress syndrome, or multi‑organ failure. The case‑fatality rate varies markedly with subtype; H5N1 has a higher mortality rate than H9N2, for example. Human-to-human transmission is limited but has been documented in some clusters, raising concerns about potential pandemic spread.

Global surveillance networks, such as the World Health Organization and national veterinary authorities, monitor avian influenza through sentinel bird farms, wildlife studies, and outbreak investigations. Control measures include culling infected flocks, movement restrictions, and strict biosecurity protocols to prevent virus spillover. In poultry, vaccination programs are employed selectively, while antiviral prophylaxis (e.g., oseltamivir) and supportive care are standard for confirmed human cases.

Research continues into vaccine development, antiviral resistance patterns, and ecological drivers that facilitate interspecies transmission. Public health guidance emphasizes avoidance of live bird markets, use of personal protective equipment for poultry workers, and immediate reporting of sick or dead birds to authorities to mitigate outbreak risks.