Thursday, January 26, 2017

WHO H7N9 Risk Assessment - Jan 2017



















#12,161



Overnight the World Health Organization released a new Influenza at the human-animal interface report - dated January 16th - that, due to China's delays in reporting, only reflects Mainland China cases through the end of December.
Therefore their total of  918 lab-confirmed cases of human infection with H7N9 as of January 16th is more than 100 cases behind the latest totals reported by Hong Kong's CHP, Taiwan's CDC, and the FAO.

On Monday, in WHO Director-General Chan On H7N9 In China,  the D-G put the number at `over 1000', and again urged that all countries promptly report cases under the IHR 2005 agreement, which has yet to be fully implemented more than a decade after it was signed.

Hence the following  reminder, which we see in nearly every avian flu update:
IHR compliance: All human infections caused by a new influenza subtype are required to be reported under the International Health Regulations (IHR, 2005).2 This includes any animal and non-circulating seasonal influenza viruses. Information from these notifications is critical to inform risk assessments for influenza at the human-animal interface.

This report also covers the outbreak of Avian H7N2 in hundreds of cats in New York City (plus 1 human infection), along with a report of an H9N2 infection in Guangdong Province last December. No human H5 infections were reported in this latest update.

Some excerpts from a much larger report follow.


Avian influenza A(H7N9) viruses
 
Current situation:


During this reporting period, China reported 110 laboratory-confirmed human cases of influenza A(H7N9) virus infection to WHO. 106 cases were reported in mainland China, three cases were reported in Hong Kong Special Administrative Region (SAR) and another case was reported in Macao SAR. Case details are presented in the table in the Annex of this document. For additional details on these cases and public health interventions, see the Disease Outbreak News.


As of 16 January 2017, a total of 918 laboratory-confirmed cases of human infection with avian influenza A(H7N9) viruses, including at least 359 deaths3, have been reported to WHO (Figure 2). According to reports received by the Food and Agriculture Organization (FAO) on surveillance  activities for avian influenza A(H7N9) viruses in China4, positives among virological samples continue to be detected mainly from live bird markets, vendors and some commercial or breeding farms. 


Risk Assessment:
1. What is the likelihood that additional human cases of infection with avian influenza A(H7N9) viruses will occur? Most human cases are exposed to the A(H7N9) virus through contact with infected poultry or contaminated environments, including live poultry markets. Since the virus continues to be detected in animals and environments, further human cases can be expected. Additional sporadic human cases of influenza A(H7N9) in other provinces in China that have notyet reported human cases are also expected.
2. What is the likelihood of human-to-human transmission of avian influenza A(H7N9) viruses? Even though small clusters of cases have been reported, including those involving healthcare workers, current epidemiological and virological evidence suggests that this virus has not acquired the ability of sustained transmission among humans, thus the likelihood is low.
3. What is the risk of international spread of avian influenza A(H7N9) virus by travellers? Should infected individuals from affected areas travel internationally, their infection may be detected in another country during travel or after arrival. If this were to occur, further community level spread is considered unlikely as this virus has not acquired the ability to transmit easily amonghumans.

Avian influenza A(H7N2) viruses

Current situation:
During this reporting period, the United States of America (USA) reported one laboratory confirmed human case of influenza A(H7N2) virus infection to WHO. The likely source of infection  in the human was through close contact with ill cats infected with an A(H7N2) virus. The infection resulted in mild illness and the individual has recovered. No human-to-human transmission of the virus has been detected thus far. Cats are not the typical host of avian influenza viruses; however, cats have been infected in the past with such viruses (e.g., different avian influenza viruses, as well as human seasonal influenza viruses). More information on influenza in cats, influenza A(H7N2), and the human infection with A(H7N2) can be found here.
Risk Assessment:
1. What is the likelihood that additional human cases of infection with avian influenza A(H7N2) viruses will occur? If the virus continues to circulate and infect cats, and humans are in close contact with infected cats, further human cases would be expected but unusual. The hygiene measures put in place following the detection of this human case have likely had an impact on the transmission of the virus from infected cats to humans.
2. What is the likelihood of human-to-human transmission of avian influenza A(H7N2) viruses? Current evidence suggests that the likelihood is low. Thus far, there has been no evidence of human-to-human transmission of this virus from this human case. There have been two previous human cases of infection with A(H7N2) virus reported in the USA5,6, and no human-to-human transmission was detected in these events. There were several presumed human cases of infection with influenza A(H7N2) in the United Kingdom in 2007 and there was no sustained human-to-human transmission detected in that event.7
3. What is the risk of international spread of avian influenza A(H7N2) virus by travellers? Should infected individuals from affected areas travel internationally, their infection may be detected in another country during travel or after arrival. If this were to occur, further community level spread is considered unlikely as this virus has not acquired the ability to transmit easily among humans.
(Continue . . . )

No comments: