What to know
This CDC spotlight article was published on March 14, 2023. Public health and animal experts gathered in Rio de Janeiro, Brazil, that week to discuss improving the region's capacity to detect and respond to outbreaks of avian influenza A(H5) (bird flu) virus in wild birds and poultry in Latin America and the Caribbean.
CDC Update
As H5 Bird Flu Spreads South in the Americas, it Poses a Threat to Animal and Human Health
March 14, 2023 – With avian influenza A H5 outbreaks in wild birds and poultry spreading to Latin America and the Caribbean, public health and animal experts are gathering in Rio de Janeiro, Brazil this week to talk about improving the region's capacity to detect and respond to these outbreaks. A workshop organized jointly by the Pan American Health Organization (PAHO), the World Health Organization (WHO), and the Pan American Foot and Mouth Disease Center (PANAFTOSA), will help participants hone their work in surveillance, early detection, and response to animal-human spread of flu, especially avian flu. Flu experts from the U.S. Centers for Disease Control and Prevention (CDC) attending the meeting will join to share experience and learn more about initiatives in participating countries.
Contemporary H5N1 viruses belonging to clade 2.3.4.4b have been circulating widely globally for years but gaining ground in North American birds and poultry beginning in May of 2022. As of March 10, 2023, clade 2.3.4.4b H5N1 viruses have been detected in 16 countries in Latin America and the Caribbean as well as the United States and Canada. The first human infection with these H5N1 viruses in South America occurred in Ecuador in January 2023. In February, Peru reported H5N1 virus infections in sea lions and pelicans following deaths of hundreds of these animals. The introduction of avian flu poses a threat to the region, requiring both animal and human health sectors to be involved in surveillance and response preparations.
The objectives of this workshop are to identify aspects of preventing, detecting, and responding to zoonotic flu, particularly avian flu, that participating groups should focus on strengthening. Additionally, the workshop aims to update guidelines on flu at the human-animal interface and PAHO recommendations to strengthen work between multiple sectors on surveillance, early detection, and response. The workshop will also review the experiences of countries that have already had avian flu infections in people and animals. This is an opportunity to strengthen regional work on the human-animal interface with WHO Collaborating Centers and strategic partners.
Internationally, CDC has been actively working in avian flu surveillance and prevention for some time, helping to coordinate efforts with public health officials to proactively prepare for and respond to H5 infections in people and animals. This workshop adds to those international efforts in prevention, surveillance, and emergency response by encouraging sharing of work on animal flu, based on the experiences of the organization's participating countries. Additionally, the workshop will help to develop a series of specific recommendations for work on zoonotic flu in humans and animals for prevention, surveillance, and emergency response, based on successful examples.
CDC has been working domestically to address the H5N1 bird flu situation as well. CDC's existing influenza surveillance systems are well-equipped to rapidly detect cases of avian influenza A virus infection, including H5N1 virus, in people. CDC's influenza virus tests, which can detect both seasonal and novel influenza A viruses, are used in all 50 U.S states and globally. Additionally, there are CDC diagnostic tests that specifically detect the current H5 viruses, which are available in public health laboratories in all 50 U.S. states and international laboratories.
An H5 candidate vaccine virus (CVV) produced by CDC is identical or nearly identical to the hemagglutinin (HA) protein of recently detected clade 2.3.4.4b H5N1 viruses in birds and mammals (including a 2022 H5 outbreak in mink in Spain) and could be used to produce a vaccine for people, if needed, and which would provide good protection. This H5 CVV is available and has been shared with vaccine manufacturers. Because flu viruses are constantly changing, CDC continually analyses viruses to identify genetic changes that suggest these viruses might spread more easily to and between people, and cause serious illness in people, or for changes that suggest reduced susceptibility to antivirals, as well as changes in the virus that might mean a new vaccine virus should be developed.
CDC, along with state and local public health partners, also continues to actively monitor people who have been exposed to infected birds and poultry for 10 days after exposure. To date, public health departments have monitored more than 6,300 people in more than 50 jurisdictions who were exposed to birds/poultry infected with H5N1 virus. Of these, more than 160 people showed symptoms and subsequently were tested for novel influenza A and seasonal flu viruses along with other respiratory viruses. H5N1 virus genetic material has been only detected in a respiratory specimen from one person in Colorado.
Additional information on protective actions around birds, including what to do if you find a dead bird, is available. CDC also has guidance for specific groups of people with exposure to poultry, including poultry workers and people responding to poultry outbreaks. CDC will continue to provide further updates to the situation and update guidance as needed. Human infections with avian influenza viruses are rare but can happen following exposure to infected birds/poultry. Even more rarely, some limited, non-sustained person-to-person spread has happened. More information about avian influenza is available on the CDC website.
The workshop in Rio de Janeiro, Brazil was organized jointly by the Infectious Hazard Management Unit of the Health Emergencies Department of the Pan American Health Organization (PAHO), the World Health Organization (WHO), and the Pan American Foot and Mouth Disease Center (PANAFTOSA). The workshop will host participants including professionals from the health and agriculture sectors of multiple countries involved in animal influenza programs. Participants also include technical representatives from WHO collaborating centers and regional reference laboratories, and representatives from organizations such as World Organization for Animal Health (WOAH) and the Food and Agriculture Organization (FAO). PAHO officials involved in technical cooperation on animal influenza also will be participating.
More information on PAHO/WHO's actions on avian influenza is available here: Avian Influenza – PAHO/WHO | Pan American Health Organization.