Bird flu is leaving a trail of death on the beaches of Brazil's far south. At least 954 aquatic mammals (mainly wolves and sea lions, but also seals) died from the H5N1 virus. Local authorities and researchers are working to bury the bodies as quickly as possible because the risk of infection is very high. The pathogen has passed from birds to mammals several times through contact with infected animals or their feces. In some isolated cases it has also spread to humans, but there are no proven cases of infection between humans. There are fears in Brazil's powerful poultry sector that the virus is spreading from wild animals to farms.
The virus arrived in South America in late 2022 and is spreading across the continent. First it caused thousands of deaths of birds and marine mammals in Peru, then it moved to Chile, and from there to Argentina and Uruguay, before jumping to Brazil. The first case in a sea lion in Brazil was detected on October 3 and most deaths were recorded during that month.
In Argentina, teams from the NGO Wildlife Conservation Society Argentina, the National University of the Center of the Province of Buenos Aires and the University of California at Davis recorded “extreme mortality” of baby elephant seals on the Valdés Peninsula between October and November. , in Patagonia. They estimated that more than 17,000 calves died across Chubut province during this year's breeding season. Normally the calf mortality rate is less than 1%, but this season 97% died. In addition to high mortality among younger animals, scientists observed a 40 to 70% decline in coastal adults and an “unusual” number of dead adult males and females.
There are no breeding colonies in Brazil, but sea lions breeding in Uruguay rest and feed on the Brazilian coast, which inevitably led to the displacement of the virus, said Larissa Oliveira, a professor at the University's Mammal Ecology Laboratory, on Tele do Rio dos Sinos (Unisinos ) and the Rio Grande do Sul Aquatic Mammal Study Group (Gemars). “It is the first time we have seen such mortality in South America,” he says, warning that the virus appears to be extremely contagious in these animals.
Things have gotten even worse with the pinnipeds (as the seal family and its relatives are called), as they are very sociable animals that are always very close to each other. A virus that is transmitted through the air and through excrement is fatal. Although little is still known about the process, evidence suggests that death is very painful for these mammals, as they suffer from disorientation, fever and seizures up to 48 hours before death. For this reason, if a person is found dying on a beach, the official recommendation today is to use euthanasia in the form of an injection after the person has been tested and confirmed to be infected.
There is also a protocol to bury them two meters under the sand as quickly as possible to prevent infection from scavengers such as seagulls or vultures or even wild dogs, which are common on the beaches of southern Brazil. “If these animals come into contact with the carcasses and become contaminated, they can transmit the virus to urban centers and who knows if they can transmit the virus inland.” […] “That is the great fear that the virus will reach the aviaries in the interior of Brazil,” comments the specialist.
Brazil is the second largest chicken meat producer in the world and the largest exporter, selling its meat to 153 countries. In 2022, 14.5 million tons of chicken meat were produced. According to the Ministry of Agriculture and Livestock, Brazil already exported 4.7 million tons between January and November this year, generating income for the economy of more than $8.8 billion.
If the flu reaches farms, the situation could be catastrophic, but the ministry is calling for calm for now. He believes that the high mortality of marine mammals on the country's southern coast “does not increase the risk of introduction of the virus into bird farms, whether commercial or domestic,” he said in his emailed response.
The main risk is exposure of domestic birds to infected wild birds. However, all it takes is for a seagull to nibble on the remains of a sea lion, become infected and then walk around a farm. For this reason, biosecurity measures are currently being strengthened in poultry farms near places where more cases have been detected in wild animals, and owners are urged to be more vigilant and quickly report suspected cases.
The ministry also recalls that, according to the findings of the World Organization for Animal Health (WHO), the fact that there are cases of avian influenza in wild animals or subsistence poultry does not affect the classification of a country as free of H5N1 poultry. commercial production. Therefore, there is currently no risk of trade restrictions with Brazil.
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