The risk of a human avian flu pandemic – 03/27/2023 – Health

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At least 58 million birds in the United States have died from H5N1, more than 3,500 sea lions have been euthanized in South America, and another 6,500 wild birds have had the virus detected in their bodies.

We are talking about avian flu, a disease whose main host is birds, both farmed and wild, caused by the influenza virus.

The passage to humans still does not seem to have occurred in a generalized way, although two cases reported in Cambodia raised an alert to the possibility of spillover.

What is spillover (or overflow): the phenomenon of passing zoonotic diseases, such as viral or bacterial infections, from other animal species to humans.

• It occurs when a pathogen manages to bypass biological barriers and infect cells from other animal groups;

• Social conditions (such as close contact with infected animals) and environmental conditions (such as degradation of natural habitats) increase the risks of spillover.

The overflow in the past caused some of the biggest epidemics known in human history, and many of the zoonoses (name given to diseases of animal origin) are now part of the list of infectious diseases of medical importance, such as HIV / AIDS, Ebola and Covid-19 itself. 19.

So far, an 11-year-old girl who died and a close member of her family have been the only reports of the new strain of H5N1 in humans.

Health authorities, such as the WHO (World Health Organization), however, do not rule out the possibility of a new epidemic. Some points still need to be investigated:

• H5N1 does not appear to be transmitted from livestock directly to humans, requiring an intermediate host;

• The cases reported in humans had a mutation of the virus present in birds;

• In addition to airborne transmission, avian flu can be transmitted by handling dead animals; therefore, it is important to be careful when handling carcasses or slaughtered animals.

Experts draw attention to the fact that the next epidemic, whatever it may be, must be caused by a zoonosis and, most likely, a virus. It is estimated that more than three quarters of all viruses in the world may have the possibility of spillover, although scientists are aware of less than 0.001% of them.

In any case, three major vaccine producers, GSK, Moderna and CSL Seqirus, are already producing doses of vaccine capable of protecting humans against avian flu.

science to live better

• Immunization of pregnant women with the DTPa vaccine (diphtheria, tetanus and acellular pertussis) significantly reduced the occurrence of cases of pertussis (also known as whooping cough) in babies up to two months old, according to a survey of more than 47,000 cases of the disease. analyzed from 2000 to 2019 in the US. The annual incidence of pertussis in babies up to one year old was 165 cases per 100,000 children before vaccination; with immunization, there was a drop to less than 15 cases per 100,000 children.

• A study published in the journal The Lancet by scientists from the United Kingdom pointed out that having a respiratory infection in childhood brings a twice as high risk in adults of dying from respiratory diseases after the age of 73. According to research, children who had bronchitis or pneumonia in the first two years of life had a 93% higher risk of premature death from respiratory problems compared to those who did not have the condition.

• In a publication in the scientific journal New England Journal of Medicine, researchers from the Global Virus Network listed proposals to eradicate polio in the world. According to the authors, the recent cases reported in New York and the poliovirus found in the London sewer system are an alert for new outbreaks of the disease. They suggest that the inactivated vaccine against the virus, currently used as a booster regimen after oral vaccination (attenuated), replace the droplet vaccine (oral) to ensure high vaccine coverage and herd immunity in the next decade.