2013-07-03-世界卫生组织-Influenza_at_the_human-animal_interface_summary_and_assessment,_4_July_2013_5页_388kb

Summary of Influenza at Human-Animal Interface (as of 4 July 2013)

Human Infection with Avian Influenza A(H5N1)

From 2003 to July 2013, there were 633 laboratory-confirmed human cases of avian influenza A(H5N1), with 377 fatalities, reported from 15 countries. Since June 2013, three new cases were reported: two in Cambodia and one in Indonesia, with two deaths. Cases are sporadic, with no evidence of community transmission. The overall public health risk remains low due to the virus's low transmissibility among humans, but sporadic infections or small clusters are possible due to poultry circulation.

Human Infection with Avian Influenza A(H7N9)

China has reported cases since March 2013, with 133 confirmed human cases and 43 deaths by July 2013. Most cases involve contact with poultry or live bird markets, and the incidence decreased after market closures but may rise with re-opening and seasonal factors. Evidence does not support sustained human-to-human transmission. Risk assessment indicates sporadic cases in affected and neighboring areas, with WHO recommending continued surveillance and preparedness.

Avian Influenza A(H6N1)

Taipei CDC reported one case in 2013, involving a 20-year-old woman with respiratory symptoms. This is the first documented symptomatic human infection with H6N1, a low-pathogenic virus common in poultry. No evidence of human-to-human spread, and risk is low for sporadic infections due to the virus's prevalence in poultry populations.

Human Infection with Influenza A(H3N2) Variant

The USA reported four cases in 2013, all linked to swine exposure at agricultural fairs. These follow earlier cases, with no hospitalizations or ongoing transmission. Risk assessment indicates potential for further cases as the virus circulates in swine during the fair season, warranting continued monitoring.

Overall Animal Outbreaks and Risk Assessment

Animal influenza outbreaks are at seasonal levels, with enhanced surveillance for H5N9 and H7N9. Most human infections are mild and sporadic. The overall public health risk remains unchanged, as community-level spread is unlikely, but global surveillance is encouraged to monitor virus evolution and potential changes in transmissibility. All human infections with non-seasonal influenza viruses are reportable under IHR (2005).