Viral infections of animals as potential of food-borne risk for public health

The current SARS-CoV-2 pandemic demonstrated the potential risk posed by animal viruses that are not primarily human pathogens. The high adaptability of some viruses reflected by the spread to novel hosts is assisted by multiple factors directly or indirectly related to human activities such as wildlife trade, ecosystem disruption, live-animal markets, exotic food consumption, and intensified tourism. RNA viruses are very adaptable because of their error-prone replication process and the likelihood of genetic recombination or reassortment in some species. Even though, when compared to bacteria, food-borne virus transmission is not the attention focus, it may represent a way of pathogen introduction to the human population. Moreover, its relevance is enhanced considering that 75% of emerging infectious agents are of zoonotic origin. This review focuses on the zoonotic food-borne transmission of some viruses that may represent a risk for public health. Aside from the ability to replicate in the human GIT, the factors required for a virus to be transmissible via the zoonotic foodborne route include its stability and the potential to infect various hosts. Most food processing techniques are effective for virus inactivation, still, these are not applicable or performed for some foods. For example, the hepatitis E virus infects pigs, wild boars, and deer and is transmitted to humans through unprocessed meat. The Crimean-Congo hemorrhagic fever virus is a tick-borne virus that occurs in ruminants, while humans can get infected by consuming un-boiled milk and undercooked meat. Flaviviruses are mainly arthropod-borne, however, there have been reports of their transmission via the food chain. Although unlikely, the possibility of food-borne transmission for influenza A viruses has been studied and cannot be dismissed. Some paramyxoviruses, also missing the common characteristics of food-borne viruses can be transmitted by the contamination of certain foods with animal excretions. The employment of the “One Health” concept, including constant epidemiological surveillance of animals and improved reporting of disease occurrence in humans, would reduce the overall risk of emerging viral diseases. Consistent application of hygienic measures is vital in facilities where animals are raised, or in which animal products are processed and sold. Thus far, a limited number of identified zoonotic food-borne viruses has been recognized, and the potential of certain viruses to be transmitted via this route should not be underestimated. Therefore, it seems reasonable to constantly update our knowledge on this matter, thus creating the basis for planning effective disease control strategies