Scientists have pinpointed a genetic mutation that was once thought to only occur in people in ferrets. For several decades scientists have been aware that ferrets can contract certain strains of flu and of a type that humans can contracts. The exact reason why this happens has been puzzling until now.
Ferrets are an important experimental animal model for human influenza and they have been used to study the 2009 H1N1 (swine flu) virus in recent years. In addition, ferrets are also used to study cardiovascular disease, nutrition, respiratory diseases, airway physiology, cystic fibrosis and gastrointestinal disease.
New analysis has found that ferrets have a mutation in a gene that is needed to manufacture a key sugar called sialic acid. Most animals can make two types of sialic acid. However, ferrets, as with humans, can only produce one type.
The sugar molecule is of significance since different flu strains have preferences for the type of sialic acid they bind to cause infection. Since ferrets share the human form of this sugar, they have an orientation towards the receptors recognised by human strains of the flu virus.
Sialic acid plays an important role in human influenza infections. Several influenza viruses have hemagglutinin activity glycoproteins on their surfaces that bind to sialic acids found on the surface of cells, especially those found in the upper respiratory tract. This is the basis of hemagglutination when viruses are mixed with cells and enter them. Many anti-influenza drugs are designed to be sialic acid analogs whereby they interfere with release of newly generated viruses from infected cells by inhibiting the viral enzymes.
The new research could help with the development of treatments and therapies for tackling diseases like flu since researchers will be able to perform initial studies on ferrets.
The research has been published in the journal Nature Communications. The research paper is called “Ferrets exclusively synthesize Neu5Ac and express naturally humanized influenza A virus receptors.”
