Parasites in Camelids, Part 2: Treatment and Control Strategies
By Stacey Byers, DVM, MS, DACVIM
Colorado State University Veterinary Teaching Hospital
In Part 1 an overview of common gastrointestinal (GI) parasites was provided. In this article, treatment and control strategies will be discussed.
Before we treat for GI parasites, we really need to know what the camelid is infected with and how severely. This is most easily determined using a fecal flotation test. A sample of fecal pellets is mashed up and mixed with a solution that helps the eggs (e.g. nematodes) or oocysts (e.g. coccidia) to float to the surface. There are several types of fecal flotation methods available. I think one of the best flotation methods is a double centrifugation method with a salt or sugar solution. The sample is spun at a high rate which helps pull the eggs to the surface of the fluid and attach to a glass coverslip for examination under the microscope. There are other fecal flotation methods available; the main differences are the types of solutions used, processing methods, and how well they float the heavier eggs/oocysts.
Fecal flotations can be performed “on farm” by owners/managers, veterinary clinics, private laboratories, and university diagnostic laboratories. It is recommended to find out what method is being used since some labs will report “few/moderate/large” amounts of eggs/oocysts seen and other times you will get an egg/oocyst count per gram of feces. This latter information is helpful for evaluating response to treatment or if there is a potential for treatment resistance. If you are performing your own farms’ fecal flotations, I recommend checking in with your veterinarian or a diagnostic laboratory every so often to make sure your evaluations are correct. Some plant pollen and seeds and air bubbles can look similar to coccidia. Also microscopes can start having issues and lead to misleading results.
I recommend checking individual animals if concerned and do periodic fecal flotation testing of your entire herd or a sampling of the herd, depending on the number of animals. It is good to test some of the high-risk animals such as crias, sick or poor growing/weight loss animals, in addition to a few healthy animals. One recommendation for herd evaluations is to test 10% of a pen or a minimum of 6 animals per pen.
When you get your lab results back it is important to remember that there will always be the potential to see eggs/oocysts in a fecal sample. It is impossible to “sterilize” the GI tract of parasites and tolerating a small number also helps keep the immune system stimulated to help keep the infection in check. This number varies with many factors such as regional environmental differences, herd stocking density, closed versus open herd, juveniles versus adults, etc. Therefore I strongly recommend talking with your veterinarian to determine the best deworming strategy for your animals.
In the past, veterinarians, owners, and drug companies recommended or used a more blanket approach to deworming. This conventional strategy of regular deworming is one of the contributing factors to the development of widespread resistance to deworming medication (anthelmintic) in many parts of the world. The GI parasites tend to retain drug resistance genes more tenaciously than most bacteria do for antibiotic resistance genes. In fact, drug resistance is thought to be a permanent characteristic of a given resistant worm “line.” As with antibiotics, deworming medications should be considered a resource to be preserved, because they do create selection pressure on the worms!
Recent data also indicate that, for most livestock populations, 80% of the worm burden in animals is concentrated in only ~ 20% of the animals. The use of regular fecal egg counts, body condition scoring, and production parameters such as weight gain/loss can be used to help determine this high risk 20% population. In an ideal situation, this high-risk group would be removed from the group; however that is not always acceptable to owners. These animals should be dewormed as needed while limiting deworming to the remainder of the pen mates, and even better, kept separated with a companion to reduce exposure to the rest of the pen mates.
Unfortunately there is no a single anthelmintic (deworming) product that can treat all the various parasites so in some cases an animal or group of animals may be provided a couple of different medications. Some of these are over the counter and can be bought in feed stores and online without a veterinary prescription, whereas others do require veterinary prescriptions.
Common deworming products are listed in the following table.
Coccidia (Eimeria species)
Treating an animal for coccidia will not immediately resolve the loose feces or diarrhea. The intestinal tract requires time to heal due to the damage the coccidia organisms cause. Diarrhea may persist for a couple of weeks so provide good nutritional support, keep quarantined with a companion, and provide additional supportive care as recommended by your veterinarian.
Medications aimed at prevention and reducing shedding of coccidia organisms are useful additions for farms that have persistent coccidia problems. Continued problems are usually due to high stocking densities, favorable coccidia weather, lots of juveniles, animals coming/going from the premises.
Nematodes [e.g. Strongyles (Haemonchus), Nematodirus, Trichuris, etc.]
Try to use only ORAL treatment to decrease GI parasite resistance. Following the use of an injectable product, the medication is secreted into the gastrointestinal tract over an extended period of time unlike when an oral medication is used. This longer persistence of the medication in the intestinal tract exposes the GI parasites to a longer subtherapeutic level of medication and aids in developing resistance.
Injectable and topical products can still be used for other medical conditions but these routes should not be used for GI parasite control. Also absorption of topical products is not known and it also can gunk up the fiber if not applied directly to the skin.
In addition to treatment strategies, management methods should be implemented as these can greatly reduce exposure and risk of disease due to GI parasites and reduce or eliminate the need for deworming treatments.
- Dung pile management – clean up the feces before the parasites have a chance to hatch out. Juveniles with diarrhea are not always fastidious about the dung pile and can defecate in other areas. Also contaminated feet (animals and people) can lead to pen contamination.
- Move to dry lot management methods or increase dispersal of animals.
- Do not feed on the ground and keep spilled feed cleaned up around feed bins, troughs, etc. Ensure good nutrition and trace mineral status for a healthy immune system.
- Reduce stocking density and stress from overcrowding or peer pressure.
- Quarantine animals showing signs of diarrhea.
- Increase farm diversity and alternate species on pastu If using cattle or small ruminants, this isn’t as effective due to sharing similar nematodes but equine, turkeys, chickens, or guinea fowl will reduce contamination outside of the dung pile area. Note: The coccidia found in domesticated fowl are not the same species that infect camelids.
An increasing number of owners want to use more organic treatment and prevention methods. There is a lot of web based discussions on products such as diatomaceous earth and copper oxide wires. Research has found that these products are not effective in treatment or preventing parasite infections. There is research occurring in the use of plants high in condensed tannins, however the plants are not that palatable and are considered invasive species in some areas of the country so I do not recommend their use until we learn more. Organic methods that can help include using the management strategies discussed above and routine fecals to determine if there is a need to treat with the traditional medications.
Common deworming products
|Coccidia (Eimeria species)
|Albon (and generics available)
|5-14 days; longer duration for E. macusaniensis
|Treatment, prevention/reduction in shedding
|5 days, 6-14 days for E. macusaniensis. See note below.
|DO NOT USE
|Prevention/reduction in shedding
|Daily during high risk times (prepartum, juveniles). Can be top dressed or formulated into pelleted feeds with a veterinarian’s prescription
Bovatec, Rumensin, and others
|Salinomycin, lasalocid, monensin (4)
|Prevention/reduction in shedding
|Nematodes [e.g. Strongyles (Haemonchus), Nematodirus, Trichuris, etc.]
|Prohibit, Levacide, and others
|Similar modes of action so parasite resistance to one of these is likely with the other products
|Rumatel, and others
|Morantel tartrate, pyrantel pamoate
|Ivomec, Dectomax, and others
|Ivermectin, doramectin, (5)
|Panacur, Safeguard, Valbazen, and others
|Fenbendazole albendazole, (6,7)
|Various protocols depending on infection load. Usually once or once daily for 3 days are common.
- This medication has been associated with polioencephalomalacia in some livestock species. It is safe at the intended dosage and if used as directed. For longer duration treatments (>5 days), some veterinarians will prescribe thiamine supplementation. Need to treat individuals rather than the water since camelids, especially crias, often don’t consume enough water to ensure adequate intak
- Only ponazuril is efficacious against all coccidia life st The medication is effective in treating clinical coccidia infections with one dose.
- Baycox is being imported by owners and unfortunately prescribed by some veterinarians. This product is not legal for use in the US. It is commonly used in other countries for treatment of coccidia in a variety of species. In the US the equivalent drug is Marquis (ponazuril). It was originally used to treat a protozoal infection in horses.
- There are reports of adverse reactions and deaths, however it is unknown if the deaths were due to overdose or actual adverse reactions. Reports are generally anecdotal while some farms have been using some of these products without problems. Please consult with your veterinarian before using.
- There is considerable GI parasite resistance to avermectins in camelids due to use in Parelaphostrongylus tenuis prevention in eastern US. Trichuris is resistant to avermectins so need to use benzimidazol
- Nematodirus appears to be relatively resistant to treatment so higher dosages are typically needed.
- Albendazole should not to be administered during first third of gestation as it is potentially teratogenic.
Click here to read Part 1, an Overview.