<i>Lawsonia intracellularis</i>Infection in Horses: 2005–2007

Frazer, Michele L.

doi:10.1111/j.1939-1676.2008.0160.x

Cited by 85 publications

(128 citation statements)

References 17 publications

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“…Since the 1990s, it has been endemic in pigs and one of the most economically important diseases in the swine industry [4]. In the last decade, the disease also has been frequently reported in weanling foals worldwide, and now is described as an emerging disease in the horse population [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Evidence of host adaptation in Lawsonia intracellularis infections

Vannucci

Pusterla

Mapes

et al. 2012

Journal of Equine Veterinary Science

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Background: Lawsonia intracellularis is the causative agent of proliferative enteropathy, an endemic disease in pigs and an emerging concern in horses. Enterocyte hyperplasia is a common lesion in every case but there are differences regarding clinical and pathological presentations among affected species. We hypothesize that host susceptibility to L. intracellularis infection depends on the species of origin of the bacterial isolate. The objective of this study was to evaluate the susceptibilities of pigs and horses to L. intracellularis infection using either a porcine or an equine isolate. Materials and methods: Twelve foals and eighteen pigs were equally divided into three groups and infected with either a porcine or an equine isolate (10 9 L. Intracellularis/challenged animal), and a saline solution (negative control group). The animals were monitored regarding clinical signs, average of daily weight gain, fecal shedding of the bacteria by PCR and humoral serological response. Results: Foals infected with the equine isolate developed moderate to severe clinical signs and maintained a lower average of weight gain compared to control foals. Fecal quantitative PCR in equine isolate-infected foals revealed higher amounts of bacterial DNA associated with longer duration of shedding compared with porcine isolateinfected foals. All four foals infected with the equine isolate demonstrated higher IgG titers in the serum compared with porcine isolate-infected foals. In the pig trial, diarrhea and seroconversion were only observed in animals infected with the porcine isolate. Pathological changes typical of proliferative enteropathy were observed in the necropsied foal infected with equine isolate and in the two necropsied pigs infected with the porcine isolate. Conclusions: Evident clinical signs, longer periods of bacterial shedding and stronger serologic immune responses were observed in animals infected with species-specific isolates. These results show that host susceptibility is driven by the origin of the isolated L. intracellularis strain.

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Section: Introductionmentioning

confidence: 99%

Evidence of host adaptation in Lawsonia intracellularis infections

Vannucci

Pusterla

Mapes

et al. 2012

Journal of Equine Veterinary Science

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“…The ages of affected animals ranged from a few days to 21 months of age, although diarrhea associated with hypoproteinemia and submandibular edema had been observed more frequently in foals 3 to 6 months old, an age group in which animals are more susceptible to and affected by L. intracellularis (Pusterla et al 2010, Vannucci et al 2012). This predisposition is most likely associated with the decline of maternal antibodies (Pusterla et al 2008a), as well as stressors such as weaning, moving to new paddocks and barns, deworming and/ or vaccination programs and/or early conditioning programs (Frazer 2008), which were performed at this farm.…”

Section: Discussionmentioning

confidence: 99%

“…However, the first serum dilution used by that author was 1:30, while serological tests in our lab were 1:60, as this dilution showed the least nonspecific labeling. Epidemiological investigations on farms with clinical cases indicate that 10-65% of healthy adult horses and foals are seropositive for L. intracellularis (Frazer 2008, Pusterla et al 2009). The percentage of positive animals ranged from 3.57% to 16.67% in Minas Gerais herds, while the properties had no cases of clinical disease, which justifies lower rates of seropositive (Guimarães-Ladeira et al 2009).…”

Section: Discussionmentioning

confidence: 99%

Equine proliferative enteropathy on a Brazilian farm

et al. 2015

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ABSTRACT. - Lawsonia intracellularis infection on a horse farm in the Midwest region of Brazil is described. Thirty-nine foals a few days to months old from a herd with 300 horses, experienced diarrhea with variable characteristics and intensities, weight loss, hyperemic mucous membranes and dehydration. In foals 3 to 6 months of age, hypoproteinemia associated with submandibular edema were also common. Intestinal fragments of a 7-month-old foal were sent to an animal disease laboratory for diagnosis. The observed macroscopic lesions were hyperemic serosa, thickening of the intestinal wall with a corrugation, thickening of the mucosa folds and reduction of intestinal lumen. Histological analysis of the small and large intestine revealed enterocyte hyperplasia of the crypts associated with diffuse marked decrease in the number of goblet cells and positive L. intracellularis antigen labeling by immunohistochemistry. Three out of 11 animals of the same property were seropositive for L. intracellularis, demonstrating the circulation of the agent throughout the farm, but none were PCR positive in fecal samples. Based on clinical signs and pathological findings, the diagnosis of equine proliferative enteropathy was confirmed.

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“…A recent large-scale study showed that only 80% of foals with presumptive diagnosis of EPE also had a positive serum titer against L. intracellularis by IPMA. 2 One must keep in mind that serologic and molecular tests will never achieve 100% accuracy in diagnosing EPE antemortem. It is rather the integration of clinical, clinicopathologic, sonographic, serologic, and molecular results that will support or rule out an EPE diagnosis.…”

mentioning

confidence: 99%

“…PCR appears to reliably demonstrate L. intracellularis in the feces of clinically affected horses early in the course of the disease. 2 As an alternative sample type to feces, rectal swabs are routinely used for the PCR detection of L. intracellularis in pigs because of the ease of collection. The purpose of the current study was to compare the molecular detection rate of L. intracellularis between feces and rectal swabs collected from foals with suspected EPE.…”

mentioning

confidence: 99%

Comparison of Feces versus Rectal Swabs for the Molecular Detection of Lawsonia Intracellularis in Foals with Equine Proliferative Enteropathy

et al. 2010

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Abstract. The purpose of the current study was to compare the molecular detection rate of Lawsonia intracellularis between feces and rectal swabs collected from 42 foals with suspected equine proliferative enteropathy (EPE). Fecal samples and rectal swabs were processed for DNA purification by using an automated extraction system. The purified DNA was then analyzed by real-time polymerase chain reaction (PCR) for the presence of the aspartate ammonia lyase (aspA) gene of L. intracellularis. Absolute quantitation was calculated by using a standard curve for L. intracellularis and expressed as copy numbers of the aspA gene of L. intracellularis per microliter of purified DNA. The combined PCR detection rate for L. intracellularis was 90%, with 38 foals testing PCR positive in feces (33 samples), rectal swabs (32), or both (27). Six foals tested PCR positive only in feces, whereas 5 tested positive only in rectal swabs. Feces yielded a significantly higher aspA gene copy number of L. intracellularis than rectal swabs. Feces and rectal swabs tested PCR negative from 4 foals. In conclusion, the results showed that feces yielded similar numbers of PCR-positive results, with a higher L. intracellularis aspA gene load than rectal swabs. By analyzing dual samples, the PCR detection rate for L. intracellularis increased from 76% and 79% for rectal swabs and feces, respectively, to 90%. Rectal swabs should be considered as an alternative sample type for EPE-suspected patients with decreased or no fecal output.Key words: Equine proliferative enteropathy; feces; horses; Lawsonia intracellularis; real-time polymerase chain reaction; rectal swab.Equine proliferative enteropathy (EPE) is a disease of foals caused by the obligate intracellular organism Lawsonia intracellularis. This emerging disease affects weanling foals and causes fever, lethargy, peripheral edema, diarrhea, colic, and weight loss. 6 The antemortem diagnosis of EPE may be challenging and relies on the presence of hypoproteinemia, exclusion of common enteric diseases, thickening of segments of the small intestinal wall observed on abdominal ultrasonography, positive serology, and molecular detection of L. intracellularis in feces. 8 One must keep in mind that a positive serologic result may represent exposure to infection rather than disease. Although no commercially available serologic assay has yet been systematically evaluated for the equine species, serologic assays have proven useful for routine diagnosis of PE in horses when combined with clinical signs and molecular detection of L. intracellularis in feces. 7,14 Several polymerase chain reaction (PCR) assays have been developed for the detection of L. intracellularis in feces. The sensitivity and specificity of the PCR technique in fecal samples has been evaluated for pigs and showed variable sensitivity and consistently high specificity. 3,5,9,13 Sensitivity is affected by sample quality and the presence of inhibitory substances in feces. PCR appears to reliably demonstrate L. intracellularis in the fec...

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Lawsonia intracellularisInfection in Horses: 2005–2007

Cited by 85 publications

References 17 publications

Evidence of host adaptation in Lawsonia intracellularis infections

Evidence of host adaptation in Lawsonia intracellularis infections

Equine proliferative enteropathy on a Brazilian farm

Comparison of Feces versus Rectal Swabs for the Molecular Detection of Lawsonia Intracellularis in Foals with Equine Proliferative Enteropathy

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