Parasitic Worms

Parasite Identification and Control

Sandworms Rule

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Introduction

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Figure 5. Coccidia eggs (oocysts). Unsporulated cyst (left) and sporulated cyst (right).

Parasitic worms are among the most important issues regarding animal health that we will deal with. They pose a constant threat to the well being of all the animals that we deal with. Parasitic worms also threaten the human companion animal bond because of the potential of cross species infection to humans. There is a significant incidence of human infection that warrants veterinary concern because of the potential negative effects that this group of parasites can have on the human pet veterinary Bond. If pet animals with parasites are considered a threat to the well being of humans, many families will forgo owning a pet. Strategic deworming practices have been developed to prevent this issue from arising and are important strategies in maintaining the relationships that our clients have with their pets. Parasitic worms are also among the most revolting things concerning the care of a pet. You must develop sensitivity to this issue when dealing with the distraught client that just found that their pet has “worms”. For example, you may know that tapeworm infection in their pet is not necessarily an emergency; this fact may not be clear to the client who has “white inchworms” crawling out of the rectum of their cat onto their bed pillow. You should empathize with the client expressing a similar disgust for the situation and be willing to offer an immediate solution to the problem. Client concerns escalate when live worms can actually be seen exiting from one orifice or another. It is important that you are able to handle these concerns with professionalism and to not discount or disregard the perceived significance of these worms by the client. Our society has dealt with worms for thousands of years and therefore there are many potentially harmful home remedies that have come into practice. For example, many clients will assume that a sick pet, regardless of the nature of the pet’s illness, is sick because of “worms”. The client may “worm” a “sick” pet before they bring them to the clinic. These well-meaning clients have the misconception that a first therapy for any sick pet is worming.

In general, parasites do not intend to seriously threaten the lives of their host, as this would ultimately lead to their own demise. For example, a pet with serious diarrhea may pass intestinal parasites because of the projectile stools and increased intestinal motility. These worms may be seen by the client and interpreted as the cause of the diarrhea. The pet may subsequently be “wormed” with a medication that may actually make the condition worse because the pet is dehydrated, debilitated, weak or otherwise sick from the underlying cause of the diarrhea. We live by the axiom that “we diagnose before we treat” which is also true for animals suspected of having internal parasites. The following discussions will help you help us deal with these situations in a knowledgeable and concerned way.

Internal parasites (worms and protozoa) have evolved over the ages with their hosts. Fossils of parasitic worms of dogs have been found along with the earliest ancestors of our pet animals. The significance is that although parasites are harmful, they have not severely damaged their host species. Parasites live at the expense of their host, yet if they kill their host, they have destroyed their “home” and will die themselves. Reproduction and propagation of the species seems to be the prime function of most parasites; therefore, it is important to understand the life cycle of the parasite as it relates to disease of the pet and control of the parasite. It seems that we humans unknowingly create unfair advantage for parasites thereby changing the balance that has developed over the ages. Parasites infecting wild animals usually pass their eggs in the stool of the infected animal. Instinctively, most animals will defecate away from “feeding stations”, “sleeping stations”, and “play stations”. This helps to prevent the transmission of the parasites back to the animal’s pack. Parasites have responded by increasing their number of eggs, using transport hosts (mice, insects) to move the eggs back into the animal’s den, and by passing from mother to young through the milk or uterus. By restricting a pet to a small area, or kennel in which there is no alternative space for a “defecation station” we expose our pets to potentially lethal infections of parasites. Pet stores, humane facilities, and some kennel situations force animals to co-exist with their own fecal material. This gives unfair advantage to the parasites and can cause a “superinfection” which threatens the existence of the host. In veterinary private practice, we witness this frequently. It is even more profound in practices that see exotic animals. Our task is to control these parasites; therefore, we must understand that this involves all aspects of the pet’s environment, as well as the pet.

Course Objectives:

After completing this material you should have mastered the following tasks:
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  • 1) Understand the importance of internal parasites to the health and care of animals.
  • 2) Be able to perform a fecal flotation and a fecal smear preparation.
  • 3) Be able to recognize eggs and larva of hookworms, roundworms, tapeworms and whipworms by fecal flotation and giardia, trichomonas and bacterial overgrowth by direct examination.
  • 4) Understand the life cycles of hookworms, roundworms, tapeworms, giardia, and whipworms and how they apply to re-worming intervals.
  • 5) To be able to communicate with a client about the common internal parasites and why we recommend twice yearly fecal examinations.
  • 6) Have a working knowledge of the worming medications that we recommend.
  • 7) Understand the concepts of strategic deworming as recommended by the Center for Disease Control.
  • 8) Be able to handle confrontations with clients regarding misunderstandings that relate to internal parasites.
  • 9) Know the costs of the services that we provide regarding worming medications.
  • 10) Be able to discuss over the telephone how to identify a potential parasite with a concerned client.
  • 11) Understand the potential public health significance of dealing with feces of animals.