The director of the Epidemic and Pandemic Prevention and Preparedness (EPP) department of the World Health Organization (WHO)Maria Van Kerkhove, has warned of a “worldwide epizootic” of bird flu. Although currently “attention is focused above all on USA“, has assured that there is a “worrying” situation in which infections are being seen in new species such as marine or terrestrial mammals, in addition to wild birds or poultry.
“We need much stronger surveillance in animals globally, not just in the US, looking at species that we know can become infected. Prevention is key in the animal and human sectors, and between animals and humans“said Dr. Van Kerkhove this Monday during the EPI-WIN webinar ‘Risk to public health of avian influenza A(H5N1) recently detected in dairy cattle’.
In this sense, the technical manager of the global flu program, Dr. Aspen Hammond, explained that, at the beginning of 2024, “there was a unexplained disease in dairy cattle which caused a drop in milk production in the US.” A fact that, in reality, “was the detection of H5N1 avian flu in cows’ milk.”
“There have also been detections of H5N1 in other animals close to the affected dairy herds, we have heard reports of infections detected in cats and raccoons, wild and domestic birds nearby. “It has been reported that there is a very high viral load of H5N1 in the milk of affected cows, and this contrasts with a low viral load from nasal swabs collected from these cows,” said Dr Hammond.
Likewise, the expert has explained that several reports indicate that asymptomatic cows have tested positive for H5N1, having also been detected in the lungs of a slaughterhouse cow that had no symptoms. Likewise, there has been contagion between cows in the same herd, and contagion between dairies associated with cattle movements within the US.
“Cow-to-cow transmission is suspected It is probably produced by mechanical means, but, again, this is one of the areas that is being investigated with a lot of work to understand how the virus is transmitted to, from and between cows,” he stressed.
Avian influenza virus infections in humans can cause illness ranging from a mild upper respiratory tract infection to more severe illness and can be fatal. “Non-respiratory symptoms have been reported in some cases. “Conjunctivitis, gastrointestinal symptoms, encephalitis and encephalopathy have also been reported in previous human infections with A(H5N1) virus,” said Dr Hammond.
However, the expert has stressed that current epidemiological and virological evidence suggests that “influenza A(H5) viruses have not acquired the capacity for sustained transmission between humans, Therefore, the probability of contagion is low.” Thus, the experts have recalled that the H5N1 avian flu is not only in the United States, but that it emerged in 1996 and since 2002 it has been “endemic” or has “spread globally,” but Yes, “it is the first time it has been observed in cows.”
In this context, the head of the WHO Food Nutrition Standards and Scientific Advice Unit, Dr. Moez Sanaa, has recommended “Do not consume raw milk, eggs or meat, especially in places where flu outbreaks have occurred on farms”, as well as “consume pasteurized or properly boiled milk”, that is, “do not consume raw milk”.
