Nuzzo said it was very likely that the Louisiana patient’s pre-existing health conditions contributed to the severity of the illness, but also pointed to the case of a Canadian teenager who was hospitalized with bird flu in November. are.
The 13-year-old girl initially went to an emergency room in British Columbia with a fever and conjunctivitis in both eyes. She was discharged home without treatment, but subsequently developed cough, vomiting, and diarrhea. A few days later, she returned to the emergency room with difficulty breathing. She was admitted to the pediatric intensive care unit and developed respiratory failure, but eventually recovered after treatment. The girl had a history of mild asthma and an elevated body mass index, according to a case report published in the New England Journal of Medicine. It is unclear how she contracted the virus.
“What this tells us is that we never know who will develop mild illness and who will develop severe illness, so we need to take these infections very seriously,” Nuzzo said. he says. “We should not assume that all future infections will be mild.”
There is another clue that may explain the seriousness of the Louisiana and British Columbia incidents. Viral samples from both patients showed some similarities. First, both are infected with the same subtype of H5N1 called D1.1, which is the same type of virus found in wild birds and poultry. This is different from the B3.13 subtype that predominates in dairy cows.
“The question now is, is this a more severe strain than the dairy cow strain?” says Benjamin Anderson, assistant professor of environment and global health at the University of Florida. So far, scientists don’t have enough data to know for sure. A small number of poultry farm workers in Washington state tested positive for the D1.1 subtype, but these people had mild symptoms and did not require hospitalization.
“In the case of the Louisiana infection, we know that the person had comorbidities. We know that the person was older. are already contributing factors to more severe outcomes,” Anderson said.
In the Louisiana and British Columbia cases, there is evidence that the virus may have evolved to cause more severe symptoms in both patients.
A CDC report in late December found a genetic mutation in a virus taken from a patient in Louisiana that may have made it more infectious to humans’ upper respiratory tract. The report said the observed changes were likely caused by replication of the virus during the patient’s illness, rather than transmission during infection, and the mutation was not present in the birds the person had contact with. It is said to mean.
Writing in the New England Journal of Medicine, the team that cared for the Canadian teen also described “alarming” mutations found in her virus samples. These changes may have made it easier for the virus to bind to and invade cells in the human respiratory tract.
Until now, bird flu has rarely been transmitted from person to person, but scientists are concerned about a scenario in which the virus acquires mutations and human transmission becomes more likely.
Currently, people who work with or are recreationally exposed to birds, poultry, or cattle are at increased risk of contracting avian influenza. To prevent illness, health authorities recommend avoiding direct contact with wild birds or other animals infected or suspected of being infected with the avian influenza virus.
(Tag Translation) Disease