Parasite Management in Camelids
Internal or gastrointestinal (GI) parasite management rather than total eradication in camelids may seem like an odd plan, but is becoming more important as we see developing parasite resistance to medications. If we borrow some valuable lessons from other livestock species, tolerating low numbers of parasites in camelids is a good thing for both the animals and owners. This management method develops immunity, decreases parasite drug resistance, saves money for owners, and finally offers peace of mind because it is impossible to completely eliminate parasites.
1. How do parasites cause immunity? As animals are exposed to parasites, bacteria, viruses, etc., their immune system develops white blood cells that are used to fight infections to these foreign organisms. Some of these organisms cause the animal to have life-long protection after just one infection. In other cases, the animal may only be protected against diseases for only a few months. We know that low level, repeated exposure to a foreign organism can help the immune system continue making the protective cells to help prevent or reduce the impact of the disease.
2. Why is drug resistance important? Parasite resistance to anthelmintics (anti-parasite drugs) is increasingly common. We now know that we cannot completely eliminate an entire population of parasites from the GI tract of an animal. After giving an anthelmintic, many parasites are killed, however, the few that remain are resistant to the drug, and with time reproduce and create a new population that is also resistant. Eggs from these parasites are then shed in the feces exposing herd-mates to the now resistant parasites. No new products are in development, so veterinarians are concerned that we may run out of effective parasite control drugs.
3. Are there ways to reduce the need for anthelmintics? Pasture and animal management strategies can help decrease animal exposure to parasites and the need for anthelmintics.
Do not overcrowd! Alpaca need grazing space, and overcrowding immediately increases the risk of parasites.
Use feed bunks rather than feeding on the ground.
Eliminating standing water and wet areas around waterers to remove the favorable environment, most parasites need to become infective.
Frequent cleanup of the dung pile and pasture rotation reduces the pasture contamination and chances of exposure. Unfortunately, young camelids are notorious for not using the dung pile, and these juveniles typically have the highest infection rates for GI parasites. Their immune systems are immature compared to older animals. Until their immune systems have brought the initial infection under control, they can cause significant pasture contamination, which can lead to infections in other juveniles or previously unexposed adults.
Quarantine pens should be used for all camelids entering your ranch. This includes new animals or those returning from breeding and shows. This policy reduces exposure of the existing herd to new parasite species as well as other diseases. Incoming animals are stressed from transportation, new surroundings, and removal from existing herd mates. The stress causes a mild immune suppression resulting in an increase in shedding of parasites or other organisms. Quarantining these animals for at least 4 weeks allows them to adjust to the new environment, feed and water, and allow their immune systems to bring infections under control
Random herd fecal sampling can be used to measure GI parasite numbers. There are two choices:
- Concentrate on 3 general groups: crias in the first 2-6 months of life, yearlings, and adults. A sampling of 3-5 animals or 10% of the pen should be adequate; or
- Set up a routine sampling program specific to the animals. The heat and humidity in the southeast challenges the animal, and parasite loads might result due to stress. Individual sampling allows you to specifically know who to monitor and/or treat.
Monitor animal behaviors. When you know your animal, you will also know their usual behaviors. Stressed or weak alpaca can have decreased immunity that might result in increased parasite load. Routine weights are an indicator of a possible increase in parasite numbers. A routine herd health program, including weights will establish patterns and alerts you to the current status of each alpaca.
4. What types of deworming programs are available?
Deworming should be performed as needed. Deworming needs to vary by your geographical location, open or closed herd, pasture – dry or irrigated, travel, stocking density, etc. Periodic fecal sampling (as described above), including fecal egg counts, will provide information as to types and numbers of parasites present and if deworming is needed. You should review your particular situation with your veterinarian, and in combination with fecal egg counts, determine the best deworming program for your situation. In particular, juveniles and older animals should be closely monitored for signs of diarrhea, decreased weight gain or weight loss, or poor fiber coats, as these can indicate parasite problems requiring more immediate attention.
Types of GI Parasites
The following information is a brief overview of the more common GI parasites seen in alpacas and llamas and some general information on the treatments available. It is strongly recommended that a veterinarian evaluate if treatment is warranted by examination of the animal or herd and fecal samples. The use of anthelmintics does not replace good management and pasture sanitation programs. Anthelmintics should not be randomly selected – it should address the specific need as well as be correct for the situation. Parasite resistance can occur by jumping from one type to another (ie, benzimidazoles to avermectins) or inconsistent (ie, random selection) use of products. Additionally, the use of anthelmintics or “dewormers” is not without risk, and all products are considered “off-label” in camelids. No products are currently approved or have manufacturer treatment guidelines for alpacas or llamas. This means the manufacturer does not guarantee safety or effectiveness for use in these species.
Coccidia (Eimeria alpacae, E. lamae, E. macusaniensis, E. punoensis)
This parasite typically causes diarrhea and weight loss or lack of gain in crias and naïve (previously unexposed) or immunosuppressed adults. There is no cross-protection between species so adults can be infected and develop clinical disease from a different species. Treatment is typically only recommended if oocyst (egg) counts are significantly high with the presence of diarrhea. However, if E. macusaniensis is suspected, treatment is often started regardless of finding oocysts in the feces since the parasite can cause significant intestinal damage.
Infection occurs by oral exposure can occur in as little as 4 days if oocysts are exposed to cool, moist conditions. Pasture management is key to reduce exposure. The oocysts die in a warm, dry pasture in 20-30 days but can persist for years in cool, damp environments. The prepatent period (time from ingestion of the oocyst to shedding in feces) is variable among species but ranges from 10 days for E. punoensis to over 40 days for E. macusaniensis.
Oocysts cause diarrhea by damaging intestinal cells. After the anthelmintic treatment is finished, feces may remain loose until the intestinal lining is repaired. In severe infections, stunting or ill-thrift with continued diarrhea may occur due to permanent damage to the intestinal lining.
- Amprolium (Corid®): A 5-day treatment (5 on, 5 off, 5 on) or a 21-day prevention program. The product can be used for treating individual animals or via water delivery for herd situations. It is best to treat individual animals in the face of an outbreak as crias may not drink the water, and not all animals will receive the same dose.
- Sulfadimethoxine (Albon®): Typically a 5-day treatment program. It is available in both liquid and tablets for individual animal treatment.
- Ponazuril (Marquis®). A newer product that targets all life stages of the coccidia. It is available as a paste.
- Decoquinate (Deccox®) is a preventative product. It is added to the feed to reduce oocyst production.B. Cryptosporidium (Cryptosporidium sp.)
Rarely seen but can cause diarrhea in young camelids, especially less than 30 days old. This is zoonotic, so humans can get it too! Use good hygiene/sanitation since no treatments are available. Keep the animal dry and well hydrated until the parasite runs its course. The prepatent period is 3-7 days.
II. NEMATODES (ROUND WORMS)
A. Strongyles (Cooperia, Haemonchus, Oesophagostomum, Ostertagia, Trichostrongylus)
There are many types of “strongyles” that cannot be differentiated by egg shape alone on fecal exams; fortunately, the treatment is similar for all. Some of these parasites can cause stunting, weight loss, and diarrhea. Haemonchus can cause rapid anemia due to blood loss.
B. Whipworms (Trichuris tenuis)
This parasite causes poor growth, diarrhea, and blood loss. This parasite is more resistant to the avermectin-type products, but the benzimidazoles are effective.
C. Nematodirus battus, N. helvetianus
Nematodirus spp. eggs are approximately 2 times the size of strongyle eggs. The parasite is a low egg producer, so any eggs present indicates a significant infection. This parasite can cause poor growth and diarrhea, especially in crias.
D. Parelaphostrongylus tenuis
Commonly called “meningeal worm”. The parasite normally infects white-tailed deer and requires a snail to continue the life cycle. When camelids and other animals eat contaminated feed, the parasite migrates through the animal and finally penetrates the spinal cord. The animal develops paralysis 50- 60 days after ingestion. This parasite is prevalent in the eastern United States but is currently not present in the western states. Prevention includes deer-proof fencing, snail-eating fowl, and the use of avermectin products.
- Benzimidazoles: There is increasing parasite resistance to many of these products, especially in sheep and goats, and also in areas of the country with favorable parasite environments. Products available include fenbendazole (Panacur®, Safe-guard®) and albendazole (Valbazen®, not recommended in pregnant animals).
- Avermectins: Effective against many internal and external parasites. Products are available in oral, injectable, or pour-on forms; however, the pour-on products can cause fiber staining and dirt build-up. Oral products are recommended since research has shown they decrease resistance development as compared to the injectable products.
- Levamisole: (Levasole®, Tramisol®), not recommended in lactating animals.
- Moxidectin: (Cydectin, Quest) requires ACCURATE dosing for weight.
III. CESTODES (TAPEWORMS)
Cestodes are more unsightly than causing illness. In compromised alpaca they can cause ill thrift. Treatment options include fenbendazole, but VERY effective treatment is ivermectin 1.87%/praziquantel 14.03% paste (Equimax). Persistent tapeworms may need treatment with Droncit.
Considerations to benefit treatments
- Use the proper dewormer at the proper dose for the proper length of time. Be sure that the alpaca gets the full amount of dewormer as underdosing is useless. Do not think more is better and double or triple the dose.
- Take alpaca off pasture to treat and return to the pasture after 3-4 days to prevent further spread of parasites.
- Deliver oral medications to alpaca with an empty stomach (as empty as possible). This can be accomplished by delivering the first thing in the morning.
- If the medication is to be delivered consecutive days, do not skip a day.
- A heavily parasitized alpaca can experience toxic responses as the breakdown of parasites occurs. Monitor the alpaca behavior and treat it accordingly.
- Repeat fecal to determine the effectiveness of the medication. Most repeat fecals should be done in 10-14 days. If the count did not drop a follow up fecal might be required to verify before you treat again. A count that doesn’t drop isn’t always an indicator of a medication that doesn’t work.
- Don’t immediately rush to treat – if the animal count is higher than you would like, but the animal hasn’t lost weight or have other changes, it is probably more beneficial to repeat fecals to monitor the rise and fall. If the count continues to rise, there should be a consideration for treatment. The time you should consider immediate treatment is if you have haemonchus as it is an aggressive parasite.
- Horses and alpaca share one parasite – strongyles. Cattle share Osteragia sp and possibly one form of Nematodirus sp. Llama, sheep, goats, and deer share several parasites.