What can farmers learn from the current bird flu outbreak in dairy cows? – Successful Farming

The multistate outbreak of highly pathogenic avian influenza (HPAI) is gaining widespread attention, primarily because of the novelty of the infections and how theyre spreading.

According to the Centers for Disease Control and Prevention (CDC), the avian influenza A(H5N1) virus has been found in cows for the first time ever. The recently confirmed cases in humans are not unprecedented, but the probable mammal-to-human spread is a first.

The outbreak of HPAI among dairy herds was first reported by USDAs Animal and Plant Health Inspection Service on March 25. As of June 21, 12 states have reported confirmed cases of the disease in dairy cattle herds, according to the CDC. Those states are Texas, Kansas, Michigan, New Mexico, Idaho, Ohio, North Carolina, South Dakota, Colorado, Minnesota, Wyoming, and Iowa.

As for the spread to humans, there have been three reported human infections related to the ongoing outbreak, as of June 21. Although the first two infected individuals reported only eye symptoms, the latest case of infection also involved upper respiratory tract symptoms, according to the CDC. Each case followed exposure to dairy cows. The probable spread of HPAI from dairy cows to humans is an example of transmission of a zoonotic disease.

The World Health Organization (WHO) defines a zoonotic disease as an infectious disease that has jumped from a non-human animal to humans. This jump, or transmission, can occur through various means, according to the CDC.

Common means of transmission are direct contact, such as exposure to bodily fluids of an infected animal, or indirect contact, such as contacting areas where animals live and roam. Zoonotic diseases can also be vector-borne (transmitted by a vector like a tick or flea), foodborne (transmitted by contaminated food), or waterborne (transmitted by contaminated water).

Some zoonotic diseases, like anthrax, are caused by bacteria. Others, such as rabies or HPAI, are caused by viruses. Still others can be caused by infectious agents like parasites.

In general, although anyone can contract a zoonotic disease, certain people are more at risk for infection. According to the CDC, those younger than 5 or older than 65 are more likely to get really sick or even die. The same goes for people with weakened immune systems and pregnant women.

Although there were certainly zoonotic diseases long before the 19th century, that is when the term for this type of disease was coined. According to the CDC, a physician and pathologist named Rudolf Virchow is credited with inventing the term zoonosis (another way to say zoonotic disease) to describe an infectious disease that passed between humans and animals. Virchows study of roundworms in swine is what got him curious about the link between human and veterinary medicine.

Currently, zoonotic diseases make up a majority of diseases in humans. Mohamed Shaheen, associate professor of microbiology at the National Research Centre in Cairo, Egypt, quantified this in his article The Concept of One Health Applied to the Problem of Zoonotic Diseases published in the scientific journal Reviews in Medical Virology. According to Shaheen, of the 1,400 infectious diseases that are known to affect humans, 60% of them originated in animals.

Zoonotic diseases are on the rise. The WHO has defined emerging diseases as those that appear in a population for the first time, or that may have existed previously but are rapidly increasing in incidence or geographic range. According to Shaheens research, 75% of emerging infectious diseases in the world are zoonotic.

Various factors have contributed to the growth of zoonotic diseases. In the scientific journal Animals, researchers from the Department of Biology, College of Staten Island, City University of New York recently outlined human-related activities that influence the spread of zoonotic diseases in the article The Impact of Human Activities on Zoonotic Infection Transmissions. The activities all relate to the expanding human population: urbanization, deforestation, tourism and zoos, wildlife exploitation and trade, and climate change.

Agriculture-related factors also drive the increase of zoonotic diseases. Those factors land-use change, food industry, and agricultural industry are all associated with the expanding human population and are unavoidable to keep the growing world fed. In the scientific journal Nature Sustainability, a group of researchers led by Jason Rohr quantified the relationship between agricultural factors and disease emergence in humans through time in an article entitled Emerging Human Infectious Diseases and the Links to Global Food Production. According to the groups work, agricultural factors were associated with almost 50% of the zoonotic diseases that emerged in humans since 1940.

Zoonotic diseases can have a large negative effect on groups of animals that become infected and, if applicable, the associated farms and farmers. The outbreak of HPAI is a current example. University of Minnesota Extension reported on March 29, just after the outbreak was announced, that the impacted dairy herds experienced up to a 20% reduction in milk production for a two- to three-week period. Needless to say, reduced milk production and the direct financial impact is not the only adverse result of the current outbreak.

The cost of zoonotic diseases on agriculture as a whole is far-reaching. Researchers from the China Academy for Rural Development and School of Public Affairs recently looked at the impact of zoonotic diseases in China on 24 main farm commodities from 2002 to 2017.

In the article, The Zoonotic Diseases, Agricultural Production, and Impact Channels: Evidence from China, which was published in the scientific journal Global Food Security, these researchers reported that, according to their research model, zoonotic diseases negatively impacted almost all main farm commodities: only 2 of the 24 commodities measured were not negatively affected.

The CDC offers several recommendations to lower your risks of zoonotic disease transmission:

The AgriSafe Network, a non-profit organization that strives to reduce health disparities found in agriculture, has these suggestions for farms:

According to the network, along with preventative measures, education and effective communication are crucial among farmers and farm workers. Understanding how the disease transmission process works, building a team, and effectively communicating within that team are essential in preventing the spread of zoonotic disease, according to the organization.

With a long history and increasing prevalence, zoonotic diseases will continue to be a fact of life in agriculture.

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What can farmers learn from the current bird flu outbreak in dairy cows? - Successful Farming