Presence of the infectious agent in Brazil has generated concern since 2023, when it was identified in the country for the first time, however, in wild birds
Confirmed it on Friday (16), two outbreaks of avian flu no. One of them – the most worrying – was recorded in a fertile egg production farm in Montenegro, in the metropolitan region of Porto Alegre, and is the first case identified in commercial birds in the country. The other focus occurred at the Sapucaia do Sul zoo, about 50 kilometers from 90 waterfreens died. As a preventive measure, the place was closed for visitation. The outbreak in Montenegro drew attention for the proportions: more than 15,000 birds died in a 17,000 squad. Those who survived have been sacrificed, and all egg production of the last four weeks is being tracked and discarded. In response, the Ministry of Agriculture and Livestock decreed a state of emergency zoosanitary for 60 days in the region, with restrictions within 10 km. The presence of the infectious agent in Brazil has generated concern since 2023, when identified in the country for the first time, however, in wild birds.
What is Avian flu?
Avian flu, or avian influenza, is an infectious disease caused by type A influenza virus that can affect birds and, more rarely, mammals, including humans. The H5N1 subtype, classified as high pathogenicity, is primarily responsible for recent outbreaks. Since 2022, cases have been persistently recorded in countries of the Americas, including Argentina, Chile, the United States and, more recently, Brazil. The disease is highly contagious between birds and its main sign is sudden death. Mortality in lot can exceed 60%, reaching 100% in more aggressive cases, according to the Brazilian Agricultural Research Company (Embrapa). Other signs include cough, nasal mucus, drop in egg production, bleeding, swelling in joints and changes in crest coloration.
Is there a risk to humans?
According to the Ministry of Health, “whenever avian influenza viruses circulate between birds, there is a risk of sporadic occurrence of human cases by exposure to infected birds or contaminated environments.” Experts explain that, despite the possibility of human infection, chances are considered very low. “Confirmation of the virus does not indicate a situation out of control,” said Isabella Ballalai, director of the Brazilian Society of Immunizations (SBIM), in an interview with Estadão. “On the contrary, it shows that the surveillance system is working.” The cases occurred almost exclusively by direct and unprotected contact with contaminated birds. Therefore, poultry professionals should use protective equipment such as masks and gloves. Domestic creations also require attention: Sudden deaths should be communicated immediately to the health authorities. Transmission between people, when it occurs, is rare, limited and inefficient.
Avian flu symptoms
In humans, initial symptoms resemble those of common flu: high fever, cough, nausea, vomiting and diarrhea. In some cases, there is rapid evolution for respiratory discomfort and severe pneumonia. Other reported symptoms include abdominal pain, nose bleeding or gums, headache and chest pain. The lethality rate reaches 50%, one of the highest among known viruses. Since 2003, the World Health Organization (WHO) has identified 874 human infections, including 458 deaths. In Brazil, there is no record of infection in humans so far.
Is it safe to consume eggs and chicken meat?
Yes. Avian flu virus does not resist heat, so well cooked foods do not transmit the disease. The guidance is to avoid raw or poorly cooked products, such as soft egg eggs, measured already recommended to avoid other eating infections.
Posted by Luisa Cardoso
*With information from Estadão Content
