On Thursday, October 15th, the Food and Agriculture Organization (FAO) of the United Nations released a warning announcing the start of a fourth wave of avian influenza H7N9 [1]. The H7N9 strain particularly threatens the poultry industry and those working directly with animals. Since its initial emergence in China in 2013, the country has seen a steady rise of human infections of H7N9 [2].
About H7N9
Avian influenza A(H7N9) is a subgroup of H7 influenza viruses that have been reported in countries across the globe – China, Australia, Canada, Mexico, the Netherlands, Italy, the United Kingdom, and the United States [3]. The majority of human infections recorded have resulted in “conjunctivitis and mild respiratory symptoms,” and have been largely associated with poultry outbreaks [3]. Human cases of H7N9 have presumably also involved direct contact as the route of infection – particularly for those whose occupation involves animal interaction or even as a result of visiting live animal markets [3]. While human-to-human transmission has been documented, there has been no evidence of sustained chains of transmission [3].
H7N9 often spreads silently in poultry, as the virus is usually asymptomatic in birds [2]. However, surveillance of the disease in China reveals that the virus may be well-established in poultry populations across the country, particularly in the southeastern region [2]. For humans, on the other hand, Chinese health authorities have approximated that 40% of reported H7N9 human infections have been fatal. Since its emergence in 2013, 271 human cases out of a total of 678, have died [2].
Because there is no commercially available vaccine in existence, prevention of H7N9 is key to protection from infection. Prevention of H7N9 includes practicing proper hand hygiene, respiratory hygiene, and food safety [5]. According to the World Health Organization (WHO), influenza viruses become inactivated by “normal temperatures for cooking meat products” [5]. Additionally, eggs can be safely consumed, as long as they are properly handled, prepared, and cooked [5]. However, it is important to note that in areas experiencing active outbreaks, consumption of raw or non-fully cooked meat and eggs is highly discouraged [5]. The closure of live poultry markets has also been implemented to interrupt transmission [6].
Wave Four
The start of the fourth wave of H7N9 began on October 2nd, according to the FAO [2]. This occurred after Chinese authorities reported two new human cases of H7N9 occurring in Zhejiang Province in September [2,4]. These two cases may be a warning of a potential outbreak [2]. Dr. Eran Raizman of FAO’s Emergency Prevention Service believes, “We expect human cases to rise sharply in the coming weeks or months, as has happened in previous years. This is due in part to the seasonal behavior of the virus, helped along by critical gaps in biosecurity commonly found in the poultry industry” [2].
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Sources
[1] http://www.fao.org/ag/againfo/programmes/en/empres/news_151015.html
[2] http://outbreaknewstoday.com/4th-wave-of-h7n9-avian-influenza-has-begun-23912/
[3] http://www.who.int/influenza/human_animal_interface/20140131_background_and_summary_H7N9_v1.pdf?ua=1
[5] http://www.who.int/influenza/human_animal_interface/faq_H7N9/en/
