Zoonotic diseases or zoonoses — such as avian influenza, swine flu, and even COVID-19 — are the most common sources of new and emerging diseases. These illnesses mutate and spread from animal hosts to infect humans, and veterinary researchers are on the front lines: preventing future pandemics by ensuring best practices for handling animal remains and screening animal populations for potentially transmissible diseases.
There are also more common, recurring disease outbreaks associated with livestock and pets we work with every day. While these diseases are usually not as infectious or potentially life-threatening as COVID-19 or avian influenza, they still contribute to thousands of illnesses every year and can threaten immunocompromised people such as the elderly, infants and those with pre-existing health conditions.
The number of outbreaks in the past couple of decades has trended upward. While there’s been no “smoking gun” that tells us why that might be the case, some people theorize that as society is further removed from agricultural production, the bulk of the population might be naïve to precautionary steps for interacting with animals or understand that their immune systems are vulnerable. The USDA reported in 2018 that only around 2.8% of the U.S. population is involved in farming, fishing, or food and beverage manufacturing.
Between 1996 and 2012, E. coli and salmonella were the most common diseases due to animal contact. Altogether, zoonoses produced around 4,300 confirmed illnesses and over 500 hospitalizations each year, according to the Centers for Disease Control and Prevention. Other disease agents related to contaminated food products or contact with infected animals include giardia, cryptosporidium and campylobacter.
There are two types of transmission — direct and indirect. A calf licking a child’s hand could be a direct transmission, whereas a child putting their mouth on a gate or a fence that’s come in contact with the calf’s saliva or manure would be a form of indirect transmission.
Prevention is straightforward: wash your hands, provide hand sanitizers, avoid eating in the barnyard, pasteurize milk and other products such as honey, and embrace inspection.
Wash your hands! It cannot be emphasized enough.
There are parts of the world where people don’t do a lot of hand washing. Even here though, a University of Utah study found that only 5 percent of people wash their hands correctly.
Their recommendation is to wet hands with clean, running water; wash hands with soap for at least 20 seconds; rinse hands in clean, running water; and finally, dry hands with a clean towel.
The common active ingredient in hand sanitizer is alcohol. Alcohol kills by drying out the bacteria or virus as it evaporates. If you’re going to use this kind of hand cleaner, do not offer paper towels near it because we don’t want to wipe the sanitizer off the hands. It must dry or evaporate off the hands to be effective.
The second point about hand sanitizers is that if there is a lot of organic debris on the surface of your hands, hand sanitizer is not effective at getting into that organic debris. You need to get the bulk of the manure, mud or whatever’s on the hands off, and then use hand sanitizer.
Eating in the barnyard is a common problem at fairs or in fair areas. There are often food stands outside animal exhibits or there may be young children who absently drop food or pacifiers and then put them back in their mouths.
A common solution is to place signs indicating that eating and drinking around livestock is prohibited.
There seems to be a movement advocating that non-pasteurized foods are better for you than pasteurized foods, and I think that research does not prove that. Pasteurization does a great job of eliminating some of the pathogens that might be in milk or cheese.
Pasteurization has helped reduce intestinal disease in the United States, however, more and more states are adopting legislation that allows the sale of raw milk. The majority of states now have regulated the sale of raw milk to some extent.
Oftentimes we hear the horrible things about inspection: It’s arduous; it’s rigorous; it’s unbearable, etc., but Inspection has actually done some great things for food safety.
The process of hazard analysis and critical control points (HACCP, pronounced “ha-sip”), in particular, has helped food safety experts to direct money and effort to areas of greatest concern.
First of all, there are real health concerns, and second, because we live in a litigious society. If we are not motivated solely by a concern for public health, it’s important to know that producers can be held accountable in court for contaminated food products. By protecting consumers, you also protect yourself.
For more information online, go to tinyurl.com/prevent-zoonoses.
Dr. Kerry Rood, DVM firstname.lastname@example.org Utah State University School of Veterinary Medicine