According to Coronavirus disease 2019 (COVID-19) Situation Report — 94, issued by the World Health Organization on April 23, 2020: “All available evidence for COVID-19 suggests that SARS-CoV-2 has a zoonotic source. Many researchers have been able to look at the genomic features of SARS-CoV-2 and have found that evidence does not support that SARS-CoV-2 is a laboratory construct. A constructed virus would show a mix of known elements within genomic sequences — this is not the case.”
While the WHO report confirms that the current viral pandemic was not “man-made,” it underscores growing concern about zoonotic diseases, those caused by organisms that can be spread from animals to people.
The U.S. Centers for Disease Control and Prevention (CDC), U.S. Department of the Interior (DOI) and U.S. Department of Agriculture (USDA) recently co-hosted a One Health Zoonotic Disease Prioritization Workshop for the United States. The collaboration agreed to a list of eight zoonotic diseases of greatest concern to the nation and made recommendations for next steps using a One Health approach.
According to Casey Barton Behravesh, director of the One Health Office, “Every year, tens of thousands of Americans get sick from diseases spread between animals and people. CDC’s One Health Office is collaborating with DOI, USDA and other partners across the government to bring together disease detectives, laboratorians, physicians and veterinarians to prevent those illnesses and protect the health of people, animals and our environment.”
The zoonotic diseases of most concern in the U.S. were identified as zoonotic influenza, salmonellosis, West Nile virus, plague, emerging coronaviruses (e.g., severe acute respiratory syndrome and Middle East respiratory syndrome), rabies, brucellosis and Lyme disease.
Six out of every 10 infectious disease cases in humans are zoonotic. One Health is an approach that recognizes the connection between people, animals, plants and their shared environment and calls for experts in human, animal and environmental health to work together to achieve the best health outcomes for all.
It's not often the role of veterinarians in human health is considered. Audrey Ruple, assistant professor of One Health epidemiology at the Purdue University College of Veterinary Medicine, said, “As veterinarians, we’re in a unique role to care for our animal patients and for our human clients as well, because we took an oath to advocate for both.”
Ruple further comments that the prevalence of zoonotic diseases points to an increased need for veterinarians and their human counterparts — general practitioners — to connect and work together today in ways most haven’t historically.
“Veterinarians understand the potential health risks associated with transmission of zoonotic and animal-only infectious diseases,” said Danelle Bickett-Weddle, associate director for the Center for Food Security and Public Health at the Iowa State University College of Veterinary Medicine. “Educating clients and staff on practical, easily implemented steps to protect themselves from zoonotic disease is an important professional task.”
People need to understand what zoonotic diseases are, especially when a pet is diagnosed with one.
“We need to explain to the client that this could affect them or a loved one, especially immunocompromised individuals,” Ruple said.
In a related One Health approach, researchers are developing antibodies against COVID-19 from cattle. According to an article published in Science Magazine by Mitch Leslie, cattle antibodies could be the newest weapon against COVID-19.
Commercial production of antibodies developed to prevent or treat disease usually depends on cultured cells or modified plants like tobacco. For 20 years, researchers now associated with SAb Biotherapeutics of Sioux Falls, South Dakota, have been using cows to produce antibodies. Genetically-altered dairy cows have immune-containing DNA that allows antibody production. Animals are able to produce large quantities of human antibodies against a pathogen protein injected into them.
“Essentially, the cows are used as a giant bioreactor,” said viral immunologist William Klimstra of the University of Pittsburgh, who has been analyzing the bovine-made antibodies’ potency against SARS-CoV-2.
Manish Sagar, infectious disease physician at the Boston University Medical Center, is skeptical about the use of cows, “until I see further proof that production of antibodies in cows is a lot more feasible and economically viable.”
So far, antibodies generated by the animals have not been approved for any disease treatment. On the other hand, Jeffrey Henderson, infectious disease specialist at the Washington University School of Medicine in St. Louis, describes the cow-produced antibodies as “the logical next step.” “The whole approach,” he said, “is based on sound science and on past experience going back more than a century.”
Ongoing collaboration between experts in animal and human health will be critical to disease prevention worldwide.
Roger Gates is the agricultural and natural resources agent for University of Georgia Extension, Whitfield County. Contact him at email@example.com.