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Camelids can acquire a great variety of internal and external parasites. Some of these are common to sheep, goats, cattle, and horses. Parasite control must be tailored to the individual farm - recommendations from other farms or other areas of the country have little usefulness on your farm. We recommend that parasite control strategies be developed through your veterinarian with the aid of fecal parasite egg counts. Further, we recommend that the Sugar Floatation Method be used for fecal egg counting because this method is more precise than traditional floatation methods. Fecal egg counts should be done at random and include all llamas if there are fewer than 10 animals on the farm, or 10 % of the herd if there are greater numbers of animals. Fecal egg counts done approximately 2 weeks after de-worming medication has been administered may aid in evaluation of development of parasite resistance. Gastrointestinal Nematodes Of the family of roundworms, the important ones are the barber pole worm (Haemonchus contortus), Trichostrongylus, the whipworm (Trichuris sp) and the thread-necked strongyle (Nematodirus). The barber pole worm and other trichostrongyles are by far the most significant parasites in this region of the country. Other species can and occasionally do cause economic loss to camelid producers but they are of lesser significance compared to the barber pole worm. Trichuris lives in the large intestine of the llama. The eggs are passed in the feces and the larva develops inside of the eggs. These eggs may survive for years. When eaten by the host, the eggs hatch in the small intestine and then migrate into the large intestine and develop into adults. The adults then lay eggs to continue the life cycle. The eggs of Nematodirus are very large and are distinctive under the microscope. They are very sturdy eggs and may even survive the winter in the feces or the soil. The larvae develop inside of the egg and may survive for several months in the soil or in vegetation. The camelid then eats the larvae on the pasture grasses which then mature into adults in the camelid’s small intestine.As a bloodsucking parasite the barber pole worm causes anemia. One thousand barber pole worm larvae can suck up to 800 cc of blood per day. The prime symptom, along with blood loss and gut damage, is anemia, which can be detected as paleness around the eyes, inside the mouth, or inside the edge of the rectum or vagina. You may also detect swelling under the jaw (bottle jaw) or low on the abdomen. Diarrhea may occur, but sometimes the animal dies before diarrhea can develop. Other symptoms include loss of weight, poor growth, unthriftiness, and a marked decrease in production.The facts about the life cycle which are important to understand are the following: 1. Adult female barber poles have tremendous egg laying potential (5,000 to 10,000 eggs or more per day). Eggs are passed in the feces and contaminate the environment. 2. Eggs hatch and pass through three larval stages, the third being infective for the next host when ingested. 3. The successful development of these stages outside the host depends on the climate. Barber pole eggs and larvae love warm, moist conditions and hate cold or very hot, dry conditions. 4. Barber pole larvae can also undergo a process called ARRESTED DEVELOPMENT where they sit quietly in the abomasum (the true stomach of ruminants) following infection and don't become adults until several months later. This is an important adaptation for keeping the worm around through cold winters when eggs and larvae don't survive well on pasture. As a result, we see an increase in parasite transmission from spring to fall. 5. The worms require about three weeks to complete their life cycle. However, if large numbers of larvae are inactive and lying in the lining of the stomach and intestines, severe parasitism can occur within 7 to 10 days after deworming. It can be difficult sometimes to decide whether you have worms resistant to a specific drug or whether animals are just becoming reinfected with parasites so rapidly that it appears that resistance is present. It is possible to determine if parasites are resistant using the Fecal Egg Count Reduction Test (FECRT). Fecal samples are collected from animals (10% of the herd or at least 5 animals) which are then dewormed. Ten to 14 days after deworming a second sample is collected and the parasite eggs are counted again. If your dewormer is still effective you should see at least a 95% reduction in fecal egg counts. It is very important that all animals be dewormed with an accurate dose when performing the FECRT. It is also important to wait about 10 days before collecting the second sample because some drugs may still decrease egg production for several days, even when the adult worms are resistant and are not killed. By waiting 10 days, you allow egg production to come back to normal. This is not a highly sensitive test for resistance and if the results indicate that the dewormer is no longer very effective you can be assured that there is widespread resistance in the population of parasites infecting your animals. Tapeworms The adult tapeworm is a white flat worm that is in segments. The tapeworm attaches to the wall of the camelid’s small intestine. Segments, or pieces of the tapeworm, which contain eggs, are passes into the feces and may be seen in the camelid’s manure. They will look like small grains of rice. The eggs are then eaten by the oribatid mite, an intermediate host. This mite lives on the grass or on the feces and contains the tapeworm larvae. Now the mite is eaten by the camelid while eating pasture grasses. The larvae attach to the camelid’s intestinal wall, mature into adults, and continue the life cycle. Meningeal Worm Meningeal worm (Parelaphostrongylus tenuis) represents a significantly different problem to llamas. These worm larvae are passed through the feces of deer (natural reservoir), are consumed by snails, and then are consumed by llamas and alpacas. Camelids are not the normal host for these worms and the latter perform "aberrant migration". During this migration, they may travel into the spinal cord and cause significant harm to the host - even causing lethal consequences. Fencing deer out of the pasture is not enough and chemicals to kill snails cause environmental residues that may be harmful and are of limited efficacy. Therefore, most prevention against meningeal worm larval infection is aimed at killing the larvae during their migration, but prior to entry into the spinal cord. This requires a de-worming frequency of at least every 4 to 6 weeks at least during the high risk periods of the year. The most efficacious anthelmintics for protection against meningeal worm have been ivermectin (1 cc of 1% ivermectin per 100 pounds body weight, injected under the skin, every 4 to 6 weeks) or fenbendazole (4.5 cc of 10 % fenbendazole per 100 pounds body weight, given orally, once daily for 3 to 5 days). Cryptosporidiosis Cryptosporidium is a coccidian protozoan parasite that affects a wide range of hosts. Clinical signs it causes are more severe in immunocompromised hosts or neonates. It is usually a self limiting disease but can cause a severe watery diarrhea. If the organism is present in substantial numbers, sites other than the small intestine where it usually inhabits can be infected. Unfortunately, secondary infections can occur simultaneously, worsening symptoms and effects of the disease. One of the most important issues with this parasite comes from its zoonotic potential - e.g. ability to infect people! It is resistant to chlorine and drinking water has been suspected as a means of transmission to humans.The prepatent period (from infection of the organism to presentation of clinical signs) is approximately 4 days. Each generation can develop and mature in 12 - 14 hours. Due to this and the autoinfection properties of the cycle, the unchallenged organism can quickly escalate into severe disease. The peak age for clinical cryptosporidium in crias is 7 to 14 days old. Although disease has been seen in older crias, this is less likely because the older cria’s immune system is capable to warding off the infection without developing severe clinical signs of disease.There is no safe and effective therapy available to treat Cryptosporidium. Supportive measures, such as fluid therapy and electrolyte replacement can be applied until the hosts immune system fights the disease. Isolation is essential once a diagnosis has been made to protect others in the herd. Limited success has been seen with lasalosid or with paromomycin in treated crias. These drugs can be dangerous and their use should only be attempted with the direct supervision of a veterinarian.The cheapest diagnostic tool is direct detection of the oocyst in the feces using an acid-fast stain. IgM, IgG and IgA can be detected using ELISA or IFA but this is not a direct test of the organism. This test is increasingly used because of the difficulty in finding organisms using fecal exam. The newest method which has good sensitivity and specificity is to detect the organisms DNA using PCR. This is however expensive, time consuming and often unpractical. Diagnosis is important for controlling the disease.This is a "disease of domestication" and is strictly hygiene associated. Keeping maternity and nursery areas clean is of paramount importance. Ensuring adequate colostrums ingestion is essential to protection of the neonatal intestine. At this time, no vaccine is available for use. Coccidiosis The symptoms of coccidiosis can vary from some loss of appetite and slight, short-lived diarrhea to severe cases involving great amounts of dark, bloody and foul smelling diarrhea, fluid feces containing mucous and blood, straining, loss of weight, rough hair coat, with up to 15% dehydration. The primary pathology associated with coccidiosis involves intestinal cell destruction. Scarring of the intestine following treatment or recovery may result in a permanently unthrifty animal. Diagnosis is based on history, symptoms and microscopic examination.In the presence of appropriate temperature, moisture and oxygen, coccidia eggs passed in the feces become infective in one to several days and readily contaminate food and water. Crias become infected after ingesting the eggs. However, presence of coccidia in the feces of normal crias does not indicate a disease situation. When an outbreak begins, only good sanitation and isolation of sick animals will prevent its spread through the herd. Coccidia eggs are resistant to disinfectants and may survive more than a year in the environment. They will stay alive in a pasture as long as they are in a moist, dark environment but will die when temperatures drop below freezing. Crias that survive through a disease outbreak are usually immune to future problems. 1. Coccidia are very host specific. Therefore the species of coccidia that infect camelids infect camelids only. Coccidia found in birds, cattle, dogs or even sheep and goats will NOT infect camelids. 2. Virtually every camelid has some level of infection, but illness occurs only in some animals. 3. THE DISEASE IS ALMOST ALWAYS GOING TO OCCUR IN YOUNG ANIMALS. CRIAS LESS THAN 5 MONTHS OF AGE ARE MORE SUSCEPTIBLE. Crias will become infected early on from the environment. Adults will have immunity to the parasite that is pretty effective in preventing disease, but not infection. 4. The primary sign of coccidiosis is diarrhea. Look for disease in stressed animals. Happy, well nourished crias left with the dam may show no diarrhea until they are, weaned. THE STRESS OF WEANING MAY DEPRESS IMMUNITY ENOUGH FOR THE COCCIDIA TO GET THE UPPER HAND AND CAUSE DISEASE. 5. Control of coccidiosis includes removing manure and not feeding off the ground. 6. Drugs used to treat clinical cases of coccidiosis include sulfa drugs and amprolium. Eimeria macusaniensis Eimeria macusaniensis infection is one of the most important emerging diseases in camelids. The causative organism is the largest of the camelid coccidia, 100 microns in length, thick-walled, and watermelon seed-shaped. It has longer prepatent (32 to 43 days) and patent (up to 40 days) periods than other species of coccidia, and also is as commonly associated with disease and death in adults as in crias. The extreme environmental stability of this organism has allowed it to build up over the 20+ years of popular camelid farming in the U.S., and that together with certain management practices including overcrowding, co-housing of crias and adults, overuse of certain pastures, and mixing stressed camelids from different locations, has lead to a real increase in clinical cases.
Eimeria macusaniensis follows the typical coccidian lifecycle, requiring 13 to 21 days on the ground for oocysts to sporulate, having multiple rounds of replication within the host, and primarily damaging the intestinal epithelium. The severity of clinical disease relates to host immunity and infective dose. Lightly infected, immunocompetent camelids may transiently shed small numbers of organisms, but will show no signs. Immunocompromised or immunonaive camelids, such as stressed adults or all crias, confronted with a large or overwhelming dose, may succumb to fatal disease in as little as 3 weeks, or as long as 2 weeks before oocysts appear in the feces. Adults within an infected herd appear to be less susceptible than ones introduced later, for example for breeding. The major signs of severe disease are those of weakness and wasting. Unless the camelid is weighed frequently, the owner frequently notices nothing wrong until the camelid collapses. Diarrhea is uncommon, except in crias. Hypoproteinemia is the major blood abnormality. Clinical abnormalities will be more comprehensively described in a soon-to-appear scientific report.
The combination of lack of specific GI signs and a negative fecal examination makes the infection easy to miss. We consider all ill-thrift camelids to be suspect, and either treat empirically or perform multiple fecal examinations over at least a 2 week period. Even then, shedding is often light (<100 oocysts/g) for the first week of patency, even in camelids with overwhelming infections. Considering that most of the anticoccidial medications available in the U.S. are most efficacious against the earlier stages of the organism, delaying treatment in suspect camelids is unlikely to be advantageous. It is more difficult to decide what to do with non-clinical shedders and their herdmates. As with other internal parasites, in general we acknowledge their presence and try to control them, not eliminate them. The long prepatent period, together with the pelleted camelid feces, offers the potential for timely manure removal to decrease pasture contamination. We believe the thick wall of the organisms imparts extreme environmental resistance, so leaving paddocks and pastures empty is of less benefit than with other GI parasites. Radical soil treatments including burning and topsoil removal have been tried, but such approaches should only be considered in extreme circumstances. As with other parasites, a good management approach decreasing stocking density, avoiding admixtures of stressed camelids, encouraging eating from above-ground feeders, avoiding excess cohabitation of crias and adults, conducting fecal parasite surveillance, timely antiparasitical treatments, and frequently checking demeanor and body condition of camelids should decrease the number of affected camelids and allow early identification of those that require treatment.
The high density of the oocyst makes it more likely to float in denser float solutions and also slower to rise. The low numbers at the onset of patency dictate that very sensitive techniques should be used. These factors should be considered when choosing the method of fecal analysis. Deworming Drugs Ivermectin: 1.5-2 cc per 100 lbs. Use monthly to prevent meningeal worm infection.
Fenbendazole: 20 mg/kg (1 cc per 10 lbs of the 10% suspension). If whipworms are a problem, use this product for 3-5 days in a row. Use every 3-4 months to control whipworms and Nematodirus.
As always, consult with your veterinarian and have fecal egg counts and parasite identification done to see what types of worms you have on the farm. This is critical to developing a FARM SPECIFIC parasite control strategy. If you have a low stocking density, you may find that you do not need to de-worm as much. If you have a high stocking density, you may find that things are getting out of control !
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