strongyle

Seasonal variation of strongylosis in working donkeys of Ethiopia: a cross-sectional and longitudinal studies

Helminths are one of the major health problems of working donkeys, often with heavy worm burden and contributing to their early demise and/or reduction in their work output. Cross-sectional and longitudinal studies were conducted to investigate the current infection prevalence and level of strongyles infection donkeys would acquire through different seasons in the mid-lowland agro-ecological zones of Ethiopia. For this purpose, faecal samples from 206 (cross-sectional study) and 102 (longitudinal study) randomly selected donkeys were directly collected from the rectum and analysed. For the longitudinal study, the 102 donkeys dewormed at the end of main rainy season, beginning of October, were monitored for the level of strongyle infection they would acquire during subsequent dry and short rainy seasons. The cross-sectional study of 206 donkey has revealed an overall infection prevalence of 89.3% (95% confidence interval (CI) = 84.4, 92.9). Donkeys in the lowland zone showed a significantly higher strongyle infection prevalence (P = 0.0126) and mean eggs per gramme of faces (EPG) (P = 0.001; 2775 EPG) compared to donkeys in the midland zone (980.8 EPG). Age, sex and body condition did not have any significant effect on either the infection prevalence or level of infection (P > 0.05). The longitudinal study has shown a significantly lower strongyle infection prevalence (P = 0.003) and level of infection donkeys acquired (P = 0.001) in the subsequent dry and short rainy seasons compared to the main rainy season following October deworming. However, these values were not significantly different between the two agro-ecological zones (P > 0.05). This study clearly showed that parasitic infections are primarily acquired during the main rainy season when pasture/herbage coverage is relatively better, and the environment is conducive for parasites survival and development. On the other hand, the finding of majority of donkeys shedding low or no eggs during the dry and short rainy seasons showed that October deworming was effective, and donkeys acquire low or no parasitic infection during the subsequent dry and short rainy seasons. Therefore, the practice of anthelmintic treatment of donkeys at the end of short rain in May may not be necessary, and October deworming once a year is sufficient.

Volume
116
Issue
7
Start page
2009
End page
2015
Publication date
Country

Equine cyathostominae can develop to infective third-stage larvae on straw bedding

Background

Domesticated grazing animals including horses and donkeys are frequently housed using deep litter bedding systems, where it is commonly presumed that there is no risk of infection from the nematodes that are associated with grazing at pasture. We use two different approaches to test whether equids could become infected with cyathostomines from the ingestion of deep litter straw bedding.

Methods

Two herbage plot studies were performed in horticultural incubators set up to simulate three straw bedding scenarios and one grass turf positive control. Faeces were placed on 16 plots, and larval recoveries performed on samples of straw/grass substrate over 2- to 3-week periods. Within each incubator, a thermostat was set to maintain an environmental temperature of approximately 10 °C to 20 °C. To provide further validation, 24 samples of straw bedding were collected over an 8-week period from six barns in which a large number of donkeys were housed in a deep litter straw bedding system. These samples were collected from the superficial bedding at 16 sites along a “W” route through each barn.

Results

No infective larvae were recovered from any of the plots containing dry straw. However, infective cyathostomine larvae were first detected on day 8 from plots containing moist straw. In the straw bedding study, cyathostomine larvae were detected in 18 of the 24 samples. Additionally, in the two barns which were sampled serially, the level of larval infectivity generally increased from week to week, except when the straw bedding was removed and replaced.

Conclusions

We have demonstrated that equine cyathostomines can develop to infective larvae on moist straw bedding. It is therefore possible for a horse or donkey bedded in deep litter straw to become infected by ingesting the contaminated straw. This has implications for parasite control in stabled equids and potentially in housed ruminants, and further investigation is required in order to establish the relative infective pressure from pasture versus straw bedding.

Publication date
Country

A survey of seasonal patterns in strongyle faecal worm egg counts of working equids of the Central Midlands and Lowlands, Ethiopia

A study was conducted for two consecutive years (1998-1999) to determine the seasonal patterns of strongyle infection in working donkeys of Ethiopia. For the purpose 2385 donkeys from midland and lowland areas were examined for the presence of parasitic ova. A hundred percent prevalence of strongyle infection with similar seasonal pattern of strongyle faecal worm egg output was obtained in all study areas. However, seasonal variations in the number of strongyle faecal worm egg output were observed in all areas. The highest mean faecal worm egg outputs were recorded during the main rainy season (June to October) in both years in all areas. Although an increase in the mean strongyle faecal egg output was obtained in the short rainy season (March-April) followed by a drop in the short dry season (May), there was no statistically significant difference between the short rainy season and long dry season (Nov-Feb) (P > 0.05). A statistically significant difference however, was obtained between the main rainy season and short rainy season, and between the main rainy season and dry season (P < 0.05). Based on the results obtained it is suggested that the most economical and effective control of strongyles can be achieved by strategic deworming programme during the hot dry pre-main rainy season (May), when the herbage coverage is scarce and helminthologically 'sterile', and the arrested development of the parasites is suppose to be terminating. This could insure the greatest proportion of the existing worm population to be exposed to anthelmintic and also reduces pasture contamination and further infection in the subsequent wet season.

Volume
40
Issue
8
Start page
637
End page
642
Publication date
Country

Gatrointestinal parasite burden, body condition and haematological values in equines in the humid tropical areas of Mexico

M. P. Valdez-Cruz
Mariano Hernandez-Gil
Presentation date

Working equines in Mexico are distributed throughout the territory, but the management practices and the health and welfare conditions differ widely between regions depending on people's customs and specific climate conditions. The Eastern coast of México has an important equine population used for work in rural production systems. Something that owners and animal workers are concerned about is how the gastrointestinal parasite burden affects the equines nutritional status and health. This is because parasite reinfestations are most likely to occur in hot, humid climates. However, there are few reliable data to support this and the lack of information makes it difficult to design treating strategies and extension activities to ensure the health and welfare of equines in these areas. To address this, a trial was designed to determine the prevalence of animals infected with gastrointestinal nematodes, the parasite burdens and their effects on the nutritional status and haematological values of working equines from a tropical area of Mexico. One hundred and twelve equines were randomly selected in five different villages of the area. One sample of faeces and one sample of blood (in a tube containing EDTA) were obtained from every animal. Gastrointestinal parasite burden using the McMaster technique, proportions of nematodes species present through a coproculture, packed cell volume, total plasma proteins, red blood cell count and white blood cell count, were measured. The nutritional status was assessed using body condition score. Data was analysed using descriptive statistics. All calculations were done per species (horses, donkeys and mules) and community (1, 2, 3, 4, and 5). Prevalence of infected equines was higher than 90%. The most common nematode species was Strongylus vulgaris. The parasite burden was low to moderate in horses and donkeys, higher in mules; however, it did not affect the body condition, nor the haematological values (P>0.05). Results suggest that in spite of the high prevalence and parasite burdens, equines involved in this trial are not being seriously affected, as shown by the body condition and haematological parameters.

Country
Published as conference proceedings
Publication date

Efficacy of two endectocides (moxidectin and ivermectin) against strongylus spp. parasites in UK donkeys

Elena Barrio
F. J. Vasquez
Presentation date

The Donkey Sanctuary is a UK based charity in Sidmouth, Devon. Its mission is to transform the quality of life for donkeys, mules and people worldwide through greater understanding, collaboration and support, and by promoting lasting, mutually life-enhancing relationships. The Donkey Sanctuary has a total of seven farms in the UK including a reception farm for new arrivals (quarantine) where the study is based. The relinquished and rescued donkeys by can arrive to the quarantine farm from different origins, for that reason, it is important to follow a health control program on arrival which includes a full coprological exam; this will determine the need of using an specific worming protocol. One of the most prevalent parasites is Strongylus spp. and it is very common to find animals with a moderate egg count who are asymtomathyc. The general recommendation is to treat donkeys with an egg count of 300 to 400 eggs per gram (The two antihelmintics used during the isolation period were two endectocides: moxidectin (Equest, 0,4 mg/Kg) and ivermectin (Eqvalan, 0,2 mg/Kg).

The worming protocol used for those animals that have been considered healthy on arrival and that they did not have received a recent antihelmintic treatment was to recieve an initial treatment with Moxidectin with a quarantine period of 48 hour without access to pasture. Those animals that have recieved a recent worming treatment( within the last 6 weeks) with ivermectin or moxidectin, they were only treated if the faecal egg count was higher than 50 epg or a different type of parasite was found (for example pulmonary nematodes). No other actions were taken in those animals with Strongylus spp. after the first faecal egg count results if they had been treated with moxidectin, otherwise the previous described protocol had been followed. 

Country
Not published as conference proceedings

Assessment of the efficacy of the anthelmintic moxidectin against cyathostomins at The Donkey Sanctuary: analysis of new and historical data using novel statistical methods

Status
Applicant(s)
Methodology

Statistical analysis of retrospective data. Phase one involves transfer of data to the lead investigator for analysis using Marcov chain Monte Carlo (MCMC) statistical methods. Phase two involves combined analysis of all FECRT data collected over the three sampling times to identify i) temporal trends in the development of resistance, ii) evidence for differential rates of development of resistance, and iii) evidence for particular groups of animals for which the rate of development of resistance seems to be accelerated compared to the other groups. Phase three of the project will involve communication of the findings to the research and clinical teams at The Donkey Sanctuary, and subsequent discussions regarding the implications of these findings for routine endoparasite control.

Aims

The overall aim of the project is to analyse the patterns of changing drug resistance to the clinically important anthelmintic Moxidectin within the small strongyle (cyathastomin) parasite population at The Donkey Sanctuary. Overall control of the endoparasite population is a complex issue so the clinical recommendations generated as part of this proposed project will be given within the context of a much larger, previously completed collaborative research project. An important part of this project is to discuss findings with the clinical and research teams at The Donkey Sanctuary in the context of recommendations for both routine annual dosing of all animals and treatment of animals with clinical disease and/or welfare compromise due to endoparasites.

Objectives

1) To examine faecal egg count reduction test (FECRT) data gathered as part of routine annual anthelmintic use at The Donkey Sanctuary autumn/winter 2018/2019, in order to assess the current efficacy of Moxidectin using state of the art statistical methods. 2) To use bespoke statistical methods to analyse the most recent FECRT along with similar data during autumn/winter 2010 and 2013 to identify trends in the pattern of resistance development, including associations between accelerated rates of resistance development and particular management patterns. 3) To interpret the findings of this project in relation to those of previous projects, and to contribute to the established recommendations for best practice to minimise the rate of development of drug resistance at The Donkey Sanctuary.

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