BVA OVERSEAS TRAVEL GRANT REPORT 2011 Gastrointestinal parasites of working equids in Kaski District, Nepal Clare Muir Introduction Kaski District, Nepal, encompasses the foothills of the Annapurna mountain range and is a challenging area to supply due to the steepness of the terrain and sometimes inhospitable weather. The majority of villages in the region are supplied by foot, as the terrain and lack of resources in this region has not yet made it possible to build roads. During the monsoon (between June and September), it is often not possible to supply the villages as the paths become too treacherous to travel. Mules are used as the main method for transportation in Kaski District due to their ability to carry large loads (typically 70kg) and nimble footwork on steep terrain. A small number of horses are also used for transportation and are additionally used for tourist treks. Currently, 344 mules are known to work in Kaski District and the main centers from which they operate are Nayapul (270mules), Thumsikot (36mules), Kannukhola (43mules) and Lwangghalel (47mules). Mules are bought into Kaski District from Northern India and typically cost around 50,000-60,000 Nepalese rupees ( 400-500). Male mules are preferred to female, due to their strength and because females are not able to work if they become pregnant. The mules are driven in trains of between 5-18 mules by the owner or a hired man each day between the villages and the main road, which is Image 1. Mules returning to Nayapul from Ghandruk supplied by trucks. There are two paths from Nayapul, one to Ghandruk and the other to Ghorapangi and mules operate solely along either one of these routes. Image 2. Mules transporting loads to the mountain villages Gastrointestinal (GI) parasitism is a major cause of economic loss and suffering for working equids worldwide. Parasitic infection of mules may cause weight loss and immunosuppression, which would reduce the work capabilities of these animals and cause mortality in acute cases. In Nepal, few studies have investigated the parasitic burdens of working equids. Currently in Kaski District, only a couple of owners regularly deworm their animals, typically using fenbendazole biannually. Three years ago, owners in Nayapul Page 1
[Type text] stopped deworming their animals due to an associated between anthelmintic administration and the death of mules. Currently, the majority of equids are treated for GI parasites on the basis of clinical signs of colic. This study was proposed to identify the prevalence of GI parasites and to correlate the level of infection with the age and body condition score of working equids in Kaski District. It is hoped that the results of this study will enable the design of an effective program for GI parasite control in Kaski District, which will hopefully improve the work capabilities and welfare of working equids in this region. This project was organized with the help of the Animal Health and Training Consultancy Service (AHTCS), the Regional Veterinary Laboratory (RVL) in Pokhara, the Himalayan Animal Rescue Trust, Dr Valerie Relf of Moredun Research Institute, Edinburgh, and the Donkey Sanctuary, Sidmouth. AHTCS provides veterinary assistance to working equids in Kaski District and therefore has established links with mule owners in the area, which enabled co-ordination of this project. The RVL provided facilities for examination of faecal samples and their staff very kindly helped me to process samples in record time! Dr Valerie Relf was most kind in answering any technical queries. Method In this study, mules were sampled from Nayapul, Thumsikot and Pokhara, as these are the main centers in Kaski District from which working equids transport loads Image 3 Loading of mules in Nayapul at 4am. Image 4 A mule about to set off with supplies for the mountain villages Page 2
Image 5 Kesher placing samples into a cool box after collection The evening prior to sampling, the mule owners received collection bags pre-labelled with the name of each animal. Where possible, the BCS and age of the mule were recorded at this time. Owners were asked to collect faecal samples from the ground, using the bags, when they observed a mule defecating. Animals from whom samples had been obtained were BCS and aged (by dental examination), by the researchers. Samples were then transported in a cool box at 4 o C to the RVL in Pokhara, a 90 minute motorbike journey from both Nayapul and Thumsicot. At the RVL, samples were analysed using the McMaster method, using saturated sodium chloride solution (NaCl, specific gravity 1.204; Ministry of Agriculture, Fisheries and Food, 1986) as the flotation fluid. Results and Discussion The prevalence of strongyle species in 136 horses and mules was 97.79%. The average count of strongyle eggs per gram of faeces was 1646, with the range of counts being between 0-8150. Based on the severity index defined by Soulsby (1982), 61.03% mules were categorized as having a high level of infection. This demonstrated that the majority of animals have heavy parasite burdens, but the question is does this affect the health of the mule? Image 6 Reading a McMaster slide in the RVL in Pokhara Strongyle species were the most common parasite identified. The adults of this species cause disease by damaging the intestinal mucosae and by reducing the nutrients available to the host. Page 3
The migration of Strongylus vulgaris larvae to the cranial mesenteric artery is associated with a localized vasculitis and accumulation of larvae can occlude the lumen of blood vessels, resulting in the death of the host. The migration of the larval forms of other strongyle species has little pathological effect on the host (Urquhart et al 1996). 80% of animals were estimated to have a body condition score of 2.5 or more, which is classified as moderate (Leighton and Hardman 1980). However, there appeared to be no relationship between EPG (eggs per gram) and BCS, with animals estimated to be in better condition despite having higher EPG counts. It can therefore be deferred that high parasite burdens are not deemed to significantly affect the condition of mules in this study. However, this study was conducted at the end of the monsoon, when animals have usually been rested and when food sources are at their most plentiful. Therefore, as time progresses into the dry season, that the condition of the mules may decline and the effects of parasitism will begin to become apparent. It must also be remembered that the EPG production of worms varies between species and that egg production is influenced by many factors and so the EPG recorded be artificially low. The majority of animals in this study were estimated to be between 6-15years of age. Higher EPG counts were observed in animals <5years. This may be because young animals have not yet Page 4
developed immunity against the parasites and are therefore more likely to show effects of parasitism. Tapeworm species were identified in 34.56% of samples. However, the identity of the tapeworm species is currently unknown. It is thought to be most like Monezia, a tapeworm of ruminants (not equids), in appearance. However, PCR testing would be required for definitive confirmation. It is thought that if the specimen is Monezia, then it may be a contaminant as the laboratory where this study was completed also ran faecal egg counts for sheep and cattle. However, when fresh equipment was used, the specimen was still observed and additionally, some owners did not have any animals with tapeworm, whereas others had a large proportion of their animals affected. Such a disparity would perhaps not be expected if the specimen was solely a contaminant. Further investigation is warranted to identify the specimen as its presence in 1/3 of animals sampled, requires clarification to enable design of an effective anthelmintic program. Above: Unknown parasite identified in 34.56% of samples Below: Strongle sp. egg identified during study Page 5
Limitations of study The collection of faecal samples for identification of worm eggs immediately caused problems, as the mules are not used to being handled and no restraining facilities were available. The initial plan to collect samples per rectum therefore had to be abandoned. Instead, the safest method of collection was to collect faeces from the ground, immediately after an animal had been observed to defaecate. However, this method increased the risk of contamination of the sample. It was important that the identity of the animal from whom the sample was taken was known, so that the results of faecal eggs counts would be meaningful to an owner. The best time to collect samples was when mules were loaded, as mules frequently defaecate when harnessed. However, loading occurs typically between 2am-6am, and so collection of faecal samples, aging and body condition scoring was performed by torchlight. As sometimes >50 mules are loaded at once, it was often difficult to co-ordinate sample and data collection. This was additionally made more difficult as the team with whom I was working, were not confident in BCS and ageing and I, not speaking Nepalese, could not communicate directly with mule owners. Storage of specimens was made difficult by the frequent power cuts, which prevented both refrigeration of samples and the manufacture of ice for sample transportation. This was of concern as the development of eggs to larvae can occur within 24hours in moderate temperatures. The use of saturated salt solution may have caused some distortion of eggs, which made identification of species of parasite egg difficult. This could be avoided by use of high quality saturated sugar solution. Conclusion This study has identified a high prevalence of strongyle and tapeworm species in working equids of Kaski Provence, Nepal. The burden of gastrointestinal parasites in these animals is thought to be unrelated to body condition and to age, in animals 5years<. Strategies to reduce gastrointestinal parasitism should include both reduction in environmental contamination and a rotational anthelmintic program. Anthelmintics should be used with caution as mules may have high burdens of encysted larvae, which may cause widespread damage to the gastrointestinal tract during larval emergence into the gut, which can be stimulated by the death of the adult worms. Anthelmintics should therefore be introduced gradually, for example the treatment of a small Page 6
number of animals (e.g. 1-2 mules), so that if problems occur the owners does not stand to lose an entire livelihood. It is also important to use a protocol which will kill encysted larvae; for example either dosing of Fenbendazole for 5 days or one dose of moxidectin. As Fenbendazole has been the only anthelmintic used in Kaski District, this immediately raises concern as to whether it is still an effective anthelmintic to use and to continue to use, due to the possible development of resistance. Faecal egg count reduction tests should therefore be performed to determine the efficacy of this product. This test measures the difference between faecal egg counts from a sample taken immediately prior to deworming and a sample taken 14 days post treatment. In addition, rotation of anthelmintic products should be employed to reduce the development of resistance. Fenbendazole is considered to be effective for 4-8weeks. In this study, low EPG were observed in animals who had received Fenbendazole 2 months prior to sampling and so it is suggested that this is an effective protocol to use. In this study, animals who had been treated 6 months prior to sampling showed no difference in EPG to mules who had never received an anthelmintic. In Nayapul, mules are housed overnight in one of two enclosures. Both enclosures are approximately 20mx20m in size and 50 animals can be pended in an enclosure at a single time. In both enclosures, mules are surrounded by excrement and when browsing on the ground overnight, it would be easy for mules to contract parasitic infection. It is therefore important that faecal contamination of the enclosures is reduced by poo-picking and that the stocking densities of the enclosure are reduced. Management of gastrointestinal parasitism is a challenging field, especially when limited by financial constraints. It is hoped that this study has inspired the need for further investigation to design an effective program to improve the welfare of working equids in this region of Nepal. Personal note This project has been an excellent experience for me and one which has helped me to develop my organization skills and further my interest in research. I have found it extremely rewarding to work in Nepal, and I was very touched by the kindness of the Nepalese people who made me feel so welcome. I have sometimes found that when volunteering it can be difficult to be an addition to the work which is already being done. However, this project offered an opportunity to make Page 7
work and inspire interest in a subject, which although was of concern to the local people, they did not have the time or resources to dedicate energy to pursue research in this area. I very much enjoyed building relationships with people during the project and I felt it gave me an excellent insight into life in Nepal, which would not have been possible as a tourist. I do hope that this project has been of use, and I cannot thank the BVA enough for their support. References Veterinary Parasitology. Urquhart et al. Blackwell Science Ltd 1996. Manual of Veterinary Parasitological Techniques 1986. Ministry of Agriculture, Fisheries and Food, Reference book 418 Leighton and Hardman 1980, Equine Nutrition, Pelham Books p9-17 Soulsby, E. J. L., 1982. Helminths, arthropods and protozoa of domesticated animals (7th edition). ELBS, London. Acknowledgements Budda Laxzui, Keshar, Dr Shiva Prasad and all who work at the Regional Veterinary Laboratory in Pokhara, Dr Valerie Relf, Dr. Dirga Kumar Lamichhane and all at AHTCS in Pokhara, the Mule owners of Kaski District, British Veterinary Association, Donkey Sanctuary (Sidmouth UK), TAWS This project was funded by the British Veterinary Association and TAWS (World Association for Transport Animal Welfare Studies). Page 8
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