Amendola A, Ranghiero A, Zanetti A, Pariani E
Public Health-Microbiology-Virology Department, University of Milan, Italy.
J Prev Med Hyg. 2011 Sep;52(3):107-10.
The A(H5N1) influenza remains a disease of birds with a significant species barrier: in the presence of some tens million cases of infection in poultry--with a wide geographical spread--, only a few hundreds cases have occurred in humans. To date, human cases have been reported in 15 countries--mainly in Asia--and all were related to the onset of outbreaks in poultry. A peak of H5N1 human cases was recorded in 2006, then decreasing in subsequent years. Despite this trend, the H5N1 virus still represents a possible threat to human health, considering that more than half of human cases of H5N1 have been fatal. Moreover, despite the drop in the number of cases, the risk of a novel pandemic cannot be excluded, since H5N1 continues to circulate in poultry in countries with elevated human population density and where monitoring systems are not fully appropriate. In addition, there is a major global concern about the potential occurrence of a reassortment between the 2009 pandemic H1N1 and the highly pathogenic H5N1 influenza viruses following a co-infection in a susceptible host. Therefore, the implementation of appropriate surveillance and containment measures is crucial in order to minimize such risk. In conclusion, H5N1 avian influenza is still a rare disease in humans but its clinical severe outcome requires a careful monitoring of the virus's ability to evolve and to trigger a new pandemic.
甲型（H5N1）流感仍然是一种具有重大物种屏障的禽类疾病：在禽类中出现了数千万例感染病例，且地域分布广泛，但人类感染病例仅有数百例。迄今为止，已有15个国家报告了人类病例，主要在亚洲，所有病例均与禽类疫情爆发有关。2006年记录到H5N1人类病例的一个高峰，随后几年有所下降。尽管有这一趋势，但考虑到超过一半的H5N1人类病例已导致死亡，H5N1病毒仍然对人类健康构成潜在威胁。此外，尽管病例数量有所下降，但新的大流行风险仍不能排除，因为H5N1在人口密度高且监测系统不完善的国家的禽类中继续传播。此外，全球还高度关注在易感宿主中共同感染后，2009年大流行H1N1与高致病性H5N1流感病毒之间可能发生重配。因此，实施适当的监测和控制措施对于将此类风险降至最低至关重要。总之，H5N1禽流感在人类中仍然是一种罕见疾病，但其临床严重后果需要密切监测该病毒的进化能力和引发新的大流行的能力。
