The CVM Staff Council is excited to highlight the Parasitology Laboratory located in the Animal Health Diagnostic Center in the April 2018 edition of CVM eNews. The Parasitology section is a full service diagnostic laboratory that can diagnose infections caused by parasites in domestic and wild animals. The CVM Staff Council had the opportunity to sit down with the Parasitology team to learn more about the work they do.

Could you give the CVM an overview of what Parasitology does?

The Parasitology Laboratory tests any testable materials of animals to detect parasites or their developmental stages to confirm parasitic infection. Parasites can be single celled organisms (protozoa), or worms (helminths) that live in the digestive tract or in other bodily tissues, or arthropods such as ticks, mites, and fleas that live on the skin of the host. Manned with highly competent core staffs, our lab employs time-tested classical parasitology protocols as well as advanced molecular methodologies for parasite detection and disease diagnosis. Despite advancements in molecular technologies, identifying parasites grossly or microscopically is the most reliable way to diagnose a parasitic infection. Since parasites produce immune response like those in viral or bacterial infections, our lab also does serology based assays for detecting a selected number of parasitic infections.

What species of animals do you test?

Parasitology welcomes any species into their lab! The most common submission includes samples from domestic pets and farm animals, wild animals, birds, fish, reptiles, zoo animals, and other exotic species. We test 'ticks' that come from human hosts. Tick testing is in collaboration with the Molecular lab and is discounted for all Cornell employees.

Are there any current research projects in the works?

We recently added molecular diagnostics testing that analyze parasite DNA to aid in disease diagnosis. Accurate disease diagnosis is based on accurate species identification. We use DNA testing for accurate parasite species determination. This is useful in scenarios when ‘look-alike’ parasite species cannot be differentiated based on their morphology. Advanced testing could differentiate between pathogenic (disease causing) and non-pathogenic parasites, or zoonotic (transmissible from animals to human) vs. non-zoonotic parasites.

We are currently validating a new staining test called the Haemonchus Egg Test for detecting Haemonchus contortus, a blood-sucking worm of small ruminants that causes anemia and leads to production loss. The eggs of this parasite found during fecal analysis are difficult to morphologically differentiate from other non-pathogenic worms of small ruminants. This new test reduces the turnaround time for Haemonchus contortus identification from two weeks to one day and will help the producer better strategize control and management of this deadly disease.

What has been the most fascinating case you have seen this year?

We had an 8-foot-long tapeworm from a dog. It was actually longer than 8-foot since it was submitted in part and the head was never located!

What is the biggest misconception that people may have about parasites?

Most people think parasites are harmful but they may be beneficial at some point in the life of a host individual. According to the hygiene hypothesis, the lack of early childhood exposure to parasites increases the susceptibility to autoimmune diseases. Take Inflammatory Bowel Syndrome (IBS) for example. This is relatively common in North America but not seen in southern Asia and Central and South America. In North America, processed foods, overly sanitized surfaces and the eradication of parasites in humans and household pets leads to the belief that the immune system is not challenged with any naturally occurring parasites resulting in an increase in autoimmune diseases such as IBS.

Parasites are very clever creatures! We’d like to highlight two examples of some of the many strategies that parasites use to move through the environment to ultimately invade a desired host. The larval stage of dog roundworm (Toxocara canis) resides dormant (encysted due to unfavorable host immune response) in the tissues such as liver, muscles, etc., of an infected adult female dog. When those larvae sense the cue that the female dog is pregnant, they travel to the womb to invade the immunologically naive unborn puppies. Once the puppies are born, the roundworms will happily mature in the intestinal tracts producing thousands of parasite eggs that pass through dog feces to kick start their life cycle in the next host.

Another example of a parasite invading an unwitting host is that of the tiny (less than 8mm length) tapeworm (Echinococuus granulosus) that lives in the intestine of wolves in the wild. The environment is contaminated by the eggs of this tapeworm in wolf feces. When a moose has eaten these eggs, the larvae will invade the lungs and develop as a large cystic mass the size of a football. With such a space occupying lesion in its lung, the moose can’t escape from a ‘wolf-chase’ as effectively as its healthy peers. Eventually, the tapeworm emerges successful in completing its life cycle!

Are parasitic diseases treatable?

Most parasitic diseases are curable with proper treatments. Since the 1980s, a new drug called lvermectin is successful in controlling most parasitic disease. However, increased drug resistance in parasites in recent years has sparked a new interest in parasitology and changed the way that treatment is administered. For example, in a horse herd approximately 30 percent will be high worm egg shedders and the remaining are either low or moderate. Previously, all horses (even the low shedders) were treated with drugs, which has resulted in the emergence of drug-resistant parasites. Now, it is recommended that only the heavy shedders get treatment. Low and moderate shedders typically remain that way for life and are healthy without any of the unnecessary treatment. Testing animals to find out “are there any parasites?” and “how many of those?” provide information to make informed treatment decisions.

Some animals are capable of removing parasites without any medical treatment at all! For example, bears have a self-cure mechanism that purges their worms before hibernation to ensure that that stay healthy and maintain positive energy balance during hibernation.

Veterinarians are now making more informed treatment decisions about parasitic infections. Parasitology offers a variety of testing that not only identifies and quantifies parasites but differentiates them into species based on their DNA. In some cases, eradicating all parasites is no longer necessary and can cause drug resistance and auto-immune diseases. Parasites play an important role in the natural world and advances in parasitology testing can lead to healthier animal and human populations.

Thank you, Parasitology, for being our CVM Staff Council’s April Spotlight! To learn more about the Parasitology Laboratory at the AHDC, please visit their webpage listed below.

Next month, the Spotlight will be on the CVM Office of Human Resources!  Do you have ideas or suggestions for an upcoming Spotlight? Email us at cvmstaffcouncil@cornell.edu!

Parasitology: Additional Information