Monday, 20 February 2012

Meaningful Uses of Man’s Best Friends


Following Ms. Bailey’s presentation on biosensors, Dr. Larry Glickman (Professor of Epidemiology and Public Health in the Department of Emergency Medicine at UNC) expanded the discussion on the practical uses of animals, namely their use as sentinels. Dr. Glickman received his VMD from Purdue in 1972, and after a 4-5 year career in small animal medicine, he decided to further his education though an MPH and DrPH at the University Of Pittsburgh School Of Public Health. It was here that he developed an interest in Toxocara canis, commonly known as Dog Roundworm. Toxocarais a common intestinal parasite found in dogs - over 95% of puppies are infected due to its transplacental and transmamary transmission. Dogs are Toxocara’s natural host thus an infection is not often debilitating, but it became apparent to Dr. Glickman that this was a major health issue due to its zoonotic capabilities and the severe implications of an infection in children. The clinical disease from Toxocara that was the most concerning was Ocular Larva Migrans (OLM), which causes ~3,000 cases of blindness yearly. Because of these staggering numbers, Dr. Glickman focused his thesis at the University of Pittsburgh on the “Development and Evaluation of Diagnostic Tests for Toxocara Infection of Children.” He was able to isolate antigens for an ELISA test to evaluate eye fluid. While this intestinal parasite was thought to be fairly limited to children, a novel case arose in which French women were infected. After some detective work, it was determined that the transmission was due to infected hunting hounds shedding eggs, pigs on the farms ingesting the eggs, the Toxocara larvae were then migrating to the muscle of the pigs, and the women were then ingesting this meat when making and seasoning sausage from these pigs. This case reinforces why the One Health Initiative is so crucial – there are new cases emerging constantly and they can involve and affect any number of populations.

Dr. Larry Glickman discussing animals as sentinels.
Dr. Glickman continued his presentation with Webster’s Dictionary definition of a sentinel as “a person or animal set to guard a group.” One of the first reported uses of animals as sentinels was the use of canaries in coalmines as early detectors of carbon monoxide. Today, with the number of pets at 170 million and growing and with them often thought of as family members, animals are being used as indicators of the human environment more and more frequently. In order to extrapolate information from our pets, the National Companion Animal Surveillance Program partnered with Banfield, and gained access to their expansive centralized electronic medical records. With this database readily accessible, dog tick infestations were easily compared to human Lyme disease incidence, and it became clear that the infestations preceded human disease, reinforcing the sentinel concept. This type of information could be very beneficial, especially if the dialogue is open between physicians and veterinarians. Dr. Glickman continued on the topic of animals as sentinels in a case of a toxic chemical spill in Georgia. Animal records were examined to determine if the human health complaints were directly related to the spill based on animals presenting with similar symptoms at a corresponding time.

Dr. Glickman’s presentation really reinforced the necessity for communication to exist among veterinarians, physicians, and health agencies. Animals can be used as sentinels in a number of ways, from understanding zoonoses and treating infections in humans, to evaluating trends in animal and human health. There are an unlimited number of uses of these sentinels, and as science progresses and the dialogue begins a lot more will be put to use.

Post authored by Gillian Clary, BS (Biology, Chemistry minor)

Up next (21 Feb):
Center of Excellence for Emerging and Zoonotic Animal Diseases and One Health
Jürgen Richt, DVM, PhD, Collaborator/Associate Professor Veterinary Microbiology and Preventive Medicine at Kansas State University; Veterinary Medical Officer National Animal Disease Center