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Lawsonia intracellularis-associated Necrotizing Enteritis in Four Weanling Horses
9th ICEID Abstracts / Journal of Equine Veterinary Science 32 (2012) S3-S95
PCR. Farms were either using a selective therapy principle based on regular fecal egg counts from all horses, or they treated strategically without using fecal egg counts. A total of 662 horses were included in the study. The overall prevalence of S. vulgaris was 12.2% at the individual level and 64.3% at the farm level. Farms using selective therapy had horse and farm prevalences of 15.4% and 83.3%, respectively, while the corresponding results for farms not using selective therapy were 7.7% and 38.9%. These findings were found statistically significant at both the horse and the farm level. In addition, the occurrence of S. vulgaris was significantly higher in horses that were dewormed more than six months prior to the study. The results suggest that basing all anthelmintic treatments on fecal egg counts can be associated with an increased prevalence of S. vulgaris. Treatment intensities on the studied farms were considerably lower than what is seen in other countries, and modifications of the parasite control programs could be considered. It remains unknown to which extent the occurrence of S. vulgaris can be associated with increased health risks for infected horses.
Lawsonia intracellularis-associated Necrotizing Enteritis in Four Weanling Horses A.E. Page 1, L.H. Fallon 2, U.K. Bryant 3, D.W. Horohov 1, T.W. Luna 4, P.S. Marsh 4, N.M. Slovis 2, K.A. Sprayberry 2, and A.T. Loynachan 3 1 Department of Veterinary Science, University of Kentucky, Lexington, KY, 40546, 2 Hagyard Equine Medical Institute, Lexington, KY, 40511, 3 Veterinary Diagnostic Laboratory, University of Kentucky, Lexington, KY, 40511, 4 Equine Medical Associates, PSC, Lexington, KY, 40583
Lawsonia intracellularis, the causative agent of equine proliferative enteropathy (EPE), has not been reported to cause necrotizing enteritis and acute death in multiple horses. Four weanling horses from central Kentucky were included after presentation to the University of Kentucky Veterinary Diagnostic Laboratory for necropsy following acute clinical deterioration. The top differential diagnosis, for all weanlings, was EPE based on the initial clinical signs and clinicopathologic data. Each weanling was euthanized, or died, within 96 hours after development of clinical signs. Necrotizing enteritis (subacute or chronic) was observed in each of the cases at necropsy. This is believed to be the reason all four weanlings demonstrated antemortem and/ or postmortem signs of systemic endotoxemia and/or bacteremia, including fulminant DIC in one weanling. Additionally, each case was positive for L. intracellularis within the small intestine and gross thickening of the mucosa was present. Based on the presence of necrotizing enteritis in each of the cases, as well as the acute clinical deterioration noted, we propose that this entity be referred to as a “necrotizing form of EPE” (N-EPE). Despite the correct preliminary diagnosis and appropriate initial treatment, all four of these weanlings succumbed to complications arising from EPE. This suggests that suspect N-EPE cases should be treated aggressively with broadspectrum antimicrobials, anti-thrombotics, and anti-
S37
endotoxic measures. While more work is needed to understand risk factors, practitioners must watch for signs associated with N-EPE in an effort to avoid acute deterioration and death.
The evaluation of African and UK bioactive plant extracts for the control of equid gastrointestinal nematodes L.E. Peachey 1, G.L. Pinchbeck 1, C.E. Scantlebury 1, G. Tefera 2, M. Getachew 3, D. Etana 4, F.A. Burden 3, A.F. Trawford 3, J.B. Matthews 5, and J.E. Hodgkinson 1 1 University of Liverpool, Liverpool, UK, 2 Society for The Protection of Animals Abroad, Debre Zeit, Ethiopia, 3 The Donkey Sanctuary, Sidmouth, UK, 4 The University of Hawassa, Hawassa, Ethiopia, 5 Moredun Research Institute, Edinburgh, UK
In the developed world the control of equid gastrointestinal (GI) nematodes, in particular cyathostomins, is increasingly challenging due the threat of anthelmintic resistance. In developing countries such as Ethiopia despite high parasite burdens, access to genuine anthelmintic treatment is limited. In both situations there is a need for alternative treatment and management regimens for effective parasite control and consequently there has been increasing interest in the use of bioactive plant extracts (BPEs) [1]. This study identified candidate plants in the UK and Ethiopia and evaluated their in vitro efficacy against cyathostomin populations derived from donkeys. A participatory rural appraisal (PRA) approach was used to identify five ethnoveterinary medicines for use in donkeys in Ethiopia. In the UK three plants were identified following extensive review of literature citing efficacy against GI nematodes of other host species and two extracts were provided courtesy of Prof Jerzy Behnke, University of Nottingham. Hydro-alcoholic extraction of dried plant material was carried out for the eight extracts prior to reconstitution in both water and DMSO. Efficacy of each extract was evaluated by egg hatch assay (EHA) and larval migration assay (LMA) using eggs and larvae recovered from the faeces of donkeys at the Donkey Sanctuary, UK. Dose response curves were produced and ED-50 values were calculated using probit analysis. Of the five Ethiopian plant extracts tested, four showed efficacy in the EHA and/or LMA. The two most efficacious were Acacia nilotica and Rumex abyssinicus in the EHA with ED50 values of 0.72mg/ml and 1.29mg/ml respectively. Of the five UK extracts four showed efficacy in the EHA and/ or LMA. The two most efficacious were Carica papaya (papaya) in the LMA and Allium sativum (garlic) in the EHA with ED-50 values of 18.9mM and 0.65mg/ml respectively. The two BPEs most efficacious in vivo for Ethiopia and the UK are to be carried forward to in vivo trials. This study has demonstrated in vitro efficacy of nine plant extracts against cyathostomins. There is evidence in the literature that these plant extracts show efficacy both in vitro and in vivo against GI nematodes in other species. Therefore these results have identified potential
PCR. Farms were either using a selective therapy principle based on regular fecal egg counts from all horses, or they treated strategically without using fecal egg counts. A total of 662 horses were included in the study. The overall prevalence of S. vulgaris was 12.2% at the individual level and 64.3% at the farm level. Farms using selective therapy had horse and farm prevalences of 15.4% and 83.3%, respectively, while the corresponding results for farms not using selective therapy were 7.7% and 38.9%. These findings were found statistically significant at both the horse and the farm level. In addition, the occurrence of S. vulgaris was significantly higher in horses that were dewormed more than six months prior to the study. The results suggest that basing all anthelmintic treatments on fecal egg counts can be associated with an increased prevalence of S. vulgaris. Treatment intensities on the studied farms were considerably lower than what is seen in other countries, and modifications of the parasite control programs could be considered. It remains unknown to which extent the occurrence of S. vulgaris can be associated with increased health risks for infected horses.
Lawsonia intracellularis-associated Necrotizing Enteritis in Four Weanling Horses A.E. Page 1, L.H. Fallon 2, U.K. Bryant 3, D.W. Horohov 1, T.W. Luna 4, P.S. Marsh 4, N.M. Slovis 2, K.A. Sprayberry 2, and A.T. Loynachan 3 1 Department of Veterinary Science, University of Kentucky, Lexington, KY, 40546, 2 Hagyard Equine Medical Institute, Lexington, KY, 40511, 3 Veterinary Diagnostic Laboratory, University of Kentucky, Lexington, KY, 40511, 4 Equine Medical Associates, PSC, Lexington, KY, 40583
Lawsonia intracellularis, the causative agent of equine proliferative enteropathy (EPE), has not been reported to cause necrotizing enteritis and acute death in multiple horses. Four weanling horses from central Kentucky were included after presentation to the University of Kentucky Veterinary Diagnostic Laboratory for necropsy following acute clinical deterioration. The top differential diagnosis, for all weanlings, was EPE based on the initial clinical signs and clinicopathologic data. Each weanling was euthanized, or died, within 96 hours after development of clinical signs. Necrotizing enteritis (subacute or chronic) was observed in each of the cases at necropsy. This is believed to be the reason all four weanlings demonstrated antemortem and/ or postmortem signs of systemic endotoxemia and/or bacteremia, including fulminant DIC in one weanling. Additionally, each case was positive for L. intracellularis within the small intestine and gross thickening of the mucosa was present. Based on the presence of necrotizing enteritis in each of the cases, as well as the acute clinical deterioration noted, we propose that this entity be referred to as a “necrotizing form of EPE” (N-EPE). Despite the correct preliminary diagnosis and appropriate initial treatment, all four of these weanlings succumbed to complications arising from EPE. This suggests that suspect N-EPE cases should be treated aggressively with broadspectrum antimicrobials, anti-thrombotics, and anti-
S37
endotoxic measures. While more work is needed to understand risk factors, practitioners must watch for signs associated with N-EPE in an effort to avoid acute deterioration and death.
The evaluation of African and UK bioactive plant extracts for the control of equid gastrointestinal nematodes L.E. Peachey 1, G.L. Pinchbeck 1, C.E. Scantlebury 1, G. Tefera 2, M. Getachew 3, D. Etana 4, F.A. Burden 3, A.F. Trawford 3, J.B. Matthews 5, and J.E. Hodgkinson 1 1 University of Liverpool, Liverpool, UK, 2 Society for The Protection of Animals Abroad, Debre Zeit, Ethiopia, 3 The Donkey Sanctuary, Sidmouth, UK, 4 The University of Hawassa, Hawassa, Ethiopia, 5 Moredun Research Institute, Edinburgh, UK
In the developed world the control of equid gastrointestinal (GI) nematodes, in particular cyathostomins, is increasingly challenging due the threat of anthelmintic resistance. In developing countries such as Ethiopia despite high parasite burdens, access to genuine anthelmintic treatment is limited. In both situations there is a need for alternative treatment and management regimens for effective parasite control and consequently there has been increasing interest in the use of bioactive plant extracts (BPEs) [1]. This study identified candidate plants in the UK and Ethiopia and evaluated their in vitro efficacy against cyathostomin populations derived from donkeys. A participatory rural appraisal (PRA) approach was used to identify five ethnoveterinary medicines for use in donkeys in Ethiopia. In the UK three plants were identified following extensive review of literature citing efficacy against GI nematodes of other host species and two extracts were provided courtesy of Prof Jerzy Behnke, University of Nottingham. Hydro-alcoholic extraction of dried plant material was carried out for the eight extracts prior to reconstitution in both water and DMSO. Efficacy of each extract was evaluated by egg hatch assay (EHA) and larval migration assay (LMA) using eggs and larvae recovered from the faeces of donkeys at the Donkey Sanctuary, UK. Dose response curves were produced and ED-50 values were calculated using probit analysis. Of the five Ethiopian plant extracts tested, four showed efficacy in the EHA and/or LMA. The two most efficacious were Acacia nilotica and Rumex abyssinicus in the EHA with ED50 values of 0.72mg/ml and 1.29mg/ml respectively. Of the five UK extracts four showed efficacy in the EHA and/ or LMA. The two most efficacious were Carica papaya (papaya) in the LMA and Allium sativum (garlic) in the EHA with ED-50 values of 18.9mM and 0.65mg/ml respectively. The two BPEs most efficacious in vivo for Ethiopia and the UK are to be carried forward to in vivo trials. This study has demonstrated in vitro efficacy of nine plant extracts against cyathostomins. There is evidence in the literature that these plant extracts show efficacy both in vitro and in vivo against GI nematodes in other species. Therefore these results have identified potential