Human infection caused by avian influenza A(H5)

Situation at a glance

Public health measures from both human and animal health agencies have been implemented. These include:

This is the first reported case of human infection caused by avian influenza A(H5) virus in Ecuador and in Latin America and the Caribbean. This human case was exposed to poultry, which died without apparent cause. Outbreaks of highly pathogenic avian influenza have been detected recently in the provinces of Cotopaxi (influenza A(H5N1)) and Bolívar, Ecuador.

Whenever avian influenza viruses are circulating in poultry, there is a risk for sporadic infection and small clusters of human cases due to exposure to infected poultry or contaminated environments. Therefore, human cases are expected, although rare.

According to the information received thus far, the virus has not been detected in other individuals beyond this single case. While further characterization of the virus from this case is pending, currently available epidemiological and virological evidence suggests that influenza A(H5) viruses have not acquired the ability for sustained transmission among humans, thus the likelihood of human-to-human spread is low. Based on available information, WHO assesses the risk to the general population posed by this virus to be low. The risk assessment will be reviewed as needed should further epidemiological or virological information become available.

A global risk assessment associated with recent influenza A(H5N1) clade 2.3.4.4b viruses was published on 21 December 2022. However, the subtype and clade information for this human case is not yet known.

There are no approved vaccines for preventing influenza A(H5) in humans. Candidate vaccines to prevent influenza A(H5) infection in humans have been developed for pandemic preparedness purposes.

Close analysis of the epidemiological situation, further characterization of the most recent viruses (human and poultry) and serological investigations are critical to assess associated risk and to adjust risk management measures in a timely manner.

Citable reference: World Health Organization (18 January 2023). Disease Outbreak News; Human infection caused by avian influenza A(H5) - Ecuador. Available at https://www.who.int/emergencies/disease-outbreak-news/item/2023-DON434