Equine Proliferative Enteropathy Research Articles

Equine Proliferative Enteropathy in a Japanese Draft Horse

Equine Proliferative Enteropathy in a Japanese Draft Horse

Molecular and serological investigation of Lawsonia intracellularis in weanling foals in Türkiye

Equine proliferative enteropathy caused by Lawsonia intracellularis has been described in weanlings in many different countries including the USA, Western Europe, Israel, Korea and Brazil but not investigated in Türkiye and Eastern Europe. The objective of the study was to determine the seroprevalence and fecal shedding of L. intracellularis in weanling foals. A cross-sectional study was designed in randomly selected 97 weanling foals with or without clinical signs from 3 different provinces of Türkiye. Total protein and albumin levels in serum samples from 97 foals were measured using automated biochemistry analyser. Serum samples and fecal samples were also tested by bELISA and real-time PCR to detect L. intracellularis-specific antibodies and -DNA, respectively. Seropositivity was found to be 25.8% by bELISA. However, none of the fecal samples were positive by real-time PCR. Statistically, no significant associations were found between seropositivity and clinical signs or serum ALB/TP levels. Seropositivity indicated the exposure of weanling foal population to L. intracellularis for the first time in Türkiye. Further investigations are needed to better understand the epidemiology of the disease in the weanlings as well as adult horse populations and potential wildlife resorvoirs in the country/region.

High Seroprevalence of Lawsonia intracellularis in Thoroughbred Farms in Southern Brazil.

The aim of the present study was to carry out a serological survey to identify the seroprevalence of Lawsonia intracellularis in six Thoroughbred farms in the Southern region of the state of Rio Grande do Sul, Brazil. During 2019 and 2020, blood samples from 686 Thoroughbred horses were obtained from six different breeding farms. Horses were divided into groups according to age: (1) broodmares (>5 years), (2) two-year-old foals, (3) yearlings, and (4) 0-6 months-old foals. Blood samples were collected by venipuncture of the external jugular vein. The detection of antibodies (IgG) against L. intracellularis was performed by Immunoperoxidase Monolayer Assay. The detection of specific antibodies (IgG) against L. intracellularis in the evaluated population was 51%. The highest detection (86.8%) of IgG was in the broodmares category, while the lowest (5.2%) was in foals of 0-6 months of age. Regarding the farms, the Farm 1 had the highest (67.4%) prevalence of seropositivity against L. intracellularis, while Farm 4 had the lowest (30.6%). There was no record of clinical manifestation of Equine Proliferative Enteropathy in the sampled animals. The results of this study show the high seroprevalence of L. intracellularis in Thoroughbred farms in the Southern of Rio Grande do Sul, suggesting a large and continuous exposure to the agent.

Phlegmonous gastritis in 2 yearling horses.

Phlegmonous gastritis was diagnosed in 2 yearling fillies that were presented with a 1-wk history of fever, lethargy, and hypoproteinemia, associated with a previous diagnosis of equine proliferative enteropathy based on clinical signs and PCR assay detection of Lawsonia intracellularis in fecal samples. Abdominal ultrasound revealed enlargement of the stomach and expansion of its submucosal layer with hypoechoic fluid, as well as thickened hypomotile small intestinal segments. Given the poor prognosis and poor response to treatment, both horses were euthanized, one on the day of presentation and the other after 3 wk of intensive medical management including a combination of antimicrobials, analgesics, and intravenous colloids. At autopsy, acute mural gastritis characterized by severe submucosal edema with suppurative inflammation (i.e., phlegmonous gastritis) and necroulcerative enteritis compatible with the necrotizing form of equine proliferative enteropathy were identified in both horses. The gastric inflammation was associated with thrombosis and mixed bacterial populations, including Clostridium perfringens, that were confined to the submucosa without evidence of mucosal involvement; toxin genes compatible with C. perfringens type C were identified in one case. Human phlegmonous gastritis is an uncommon, often-fatal pyogenic infection that is often associated with mucosal injury, bacteremia, or immunocompromise. Our finding of this unusual gastric lesion in 2 horses with similar signalment, clinical disease, and spectrum of postmortem lesions suggests a similar etiopathogenesis that possibly involves local, regional, or distant hematogenous origin, and should be considered a potential complication of gastrointestinal mucosal compromise in horses.

Prevalence of equine proliferative enteropathy in Hidaka district, Hokkaido, over five seasons.

Equine proliferative enteropathy (EPE) is an equine infectious disease that can lead to severe weight loss and hyperplasia of the intestinal mucosa due to infection with Lawsonia intracellularis. In this study, we investigated the prevalence of EPE in a major Thoroughbred breeding area: Hidaka district, Hokkaido, Japan. Of the 252 symptomatic horses that we tested, 192 EPE cases (76.2%), including 8 fatal cases, were confirmed from April 2015 to March 2020 by etiological and/or serological investigation. Most of the EPE cases were observed in foals (88.5%), with fewer cases in yearlings (7.3%) and adults (4.2%). Asymptomatic infection was observed in 62.9% of the horses kept with affected horses. These results suggest that EPE is an enzootic disease in Hidaka district.

Evaluation of the detection of antibodies against Lawsonia intracellularis and changes in serum biochemistry in foals with and without equine proliferative enteropathy

Evaluation of the detection of antibodies against Lawsonia intracellularis and changes in serum biochemistry in foals with and without equine proliferative enteropathy

Kinetics of Lawsonia intracellularis antibodies in foals on a breeding farm with equine proliferative enteropathy

Kinetics of Lawsonia intracellularis antibodies in foals on a breeding farm with equine proliferative enteropathy

Occurrence of Lawsonia intracellularis in horses raised in three regions of the state of Paraná, Brazil

Lawsonia intracellularis is a bacterium already described in several species and most prevalent in pigs, in which it causes enteric problems. Horses can also be affected, developing a disease known as equine proliferative enteropathy, which results from the proliferation of intestinal crypt cells in response to infection by the bacterium. Despite the existence of reports of the disease in several countries, including Brazil, there are still no reports of the disease or epidemiological studies of its occurrence in symptomatic or asymptomatic horses in the state of Paraná. Thus, the present study was conducted to examine the occurrence of L. intracellularis in asymptomatic horses raised in the west, northwest and north regions of Paraná by means of serological testing and the real-time polymerase chain reaction (qPCR) technique. In the serological approach, the immunoperoxidase monolayer assay (IPMA) technique was employed. Feces were processed and subjected to qPCR. In total, samples were collected from 162 animals from 20 farms. Of these, 9/162 (5.55%) showed specific antibodies against L. intracellularis. Real-time PCR, on the other hand, identified 7/162 (4.32%) fecal samples positive for the presence of the bacterium. When the techniques were compared, none of the samples was positive by both, demonstrating that, for a better diagnosis, they must be performed together. In contrast to most reports in horses, the present study describes higher serological and molecular occurrence in animals older than two years. These results are of great epidemiological relevance, as they indicate that the bacterium is present in the sampled regions of the state of Paraná. Therefore, the disease must be included in the differential diagnosis of diseases with similar clinical manifestations.

Genotyping of Equine Lawsonia intracellularis Sampled in Japan by Using Multilocus Variable-Number Tandem Repeat Analysis

The incidence of equine proliferative enteropathy, caused by Lawsonia intracellularis, is increasing around the world. To investigate the relationships of variable-number tandem repeat (VNTR) patterns with host species and clinical status in horses, multilocus VNTR analysis (MLVA) was applied to 98 L. intracellularis samples collected from horses, seven from pigs, seven from wildlife, one vaccine strain, and 17 public strains. The VNTR patterns were highly diverse: a total of 130 samples identified 99 distinct patterns, and the 98 horses were classified into 71 different patterns. A phylogenetic tree based on the MLVA showed three clusters: porcine, equine, and miscellaneous cluster. The equine cluster contained 46 horse samples, of which 42 (91.3%) were collected from two sampling areas. The MLVA could discriminate horse samples from pig, but the horse samples in the miscellaneous cluster could not be distinguished from wildlife samples. As for clinical data of the horses, the VNTR patterns were unrelated to horse age, clinical signs, and clinical outcomes. This study shows that VNTR patterns had no clear connection with equine clinical status, but the MLVA could be useful to investigate its epidemiological relationships, and interspecific transmission of L. intracellularis between horse and wildlife cannot be ruled out.

High Seroprevalence Against Lawsonia intracellularis Among Adult Horses in Belgium

Lawsonia intracellularis (LI) is an obligate intracellular gram-negative rod causing equine proliferative enteropathy (EPE). Occasional cases of EPE have been reported in foals living in Belgium, but the seroprevalence of equine LI in this country is unknown. The target population included clinically healthy adult horses, whose blood samples were collected and analyzed for specific IgG antibodies against LI using a blocking enzyme-linked immunosorbent assay test. The results were expressed as percentage of inhibition (PI). Samples that had a PI <20% were judged as negative, those between 20 and 30% as inconclusive, and those >30% were considered positive. A total of 356 blood samples were analyzed with 352 horses (98.8%) testing positive, 2 horses (0.6%) testing negative, and 2 horses (0.6%) showing inconclusive results. The large percentage of seropositive samples obtained in this study confirms a widespread exposure of Belgian horses to LI.

Investigation of the Usefulness of Serum Amyloid A in Supporting the Diagnosis of Equine Proliferative Enteropathy

The objective of this study was to determine if serum amyloid A (SAA), a major acute-phase protein, could help support the diagnosis of equine proliferative enteropathy (EPE) caused by Lawsonia intracellularis infection in foals. Archived serum samples from 101 foals with enteric signs and hypoproteinemia were available for SAA testing. Based on immunodiagnostics for L. intracellularis, the foals were divided into EPE-suspect (67) and non–EPE-suspect cases (34). Serum amyloid A values ranged from 0 to 2,761 μg/mL (median 466 μg/mL) and from 0 to 2,555 μg/mL (median 192 μg/mL) for the EPE-suspect and the non–EPE-suspect cases, respectively. Although SAA can be measured patient-side and help determine the severity of the underlying inflammatory condition, SAA was unable to consistently support the diagnosis of EPE in hypoproteinemic foals with enteric signs.

Lawsonia intracellularis associated equine proliferative enteropathy in Danish weanling foals

BackgroundLawsonia intracellularis, an obligate intracellular bacterium, causes equine proliferative enteropathy, mainly in horses around weaning. This disease is rarely reported in the Scandinavian countries.ResultsFive cases of equine proliferative enteropathy were diagnosed between 2008–2016 at the University of Copenhagen Large Animal Teaching Hospital. Cases were Danish Warmbloods and a Friesian horse, aged 6–7 months, presenting with typical clinical signs of lethargy, poor body condition, pyrexia and diarrhea. Clinical pathology was consistent with previous reports of severe hypoalbuminemia and leukocytosis. Diagnosis was confirmed by fecal polymerase chain reaction, serum immunomonolayer peroxidase assay and/or immunofluorescence and fluorescence in situ hybridization performed on formalin-fixed ileum samples. Concurrent intestinal parasitism was present in all five cases. Treatment consisted of antimicrobial therapy, anti-inflammatories, intravenous crystalloids and plasma. Three foals were euthanised due to deterioration and poor response to treatment, one with complications of septic arthritis and Strongylus vulgaris associated intestinal infarct. The other two foals survived and were reported by the owners to be healthy on long-term follow-up.ConclusionsEquine proliferative enteropathy is a disease to consider in young horses presenting with diarrhea and hypoproteinemia in Denmark.

In vitro antimicrobial activity against equine Lawsonia intracellularis strains.

Lawsonia intracellularis is the aetiologic agent of equine proliferative enteropathy (EPE). This emerging equine disease leads to diarrhoea, severe protein loss and can result in death if left untreated. Timely treatment of EPE is critical for recovery from the disease, and hence, information about antimicrobial susceptibilities of equine L. intracellularis strains to antimicrobials used in horses is needed. However, L. intracellularis is an obligate intracellular bacterium and so must be isolated and maintained in cell cultures. To determine the in vitro antimicrobial activity of 14 antimicrobials against two equine L. intracellularis strains. In vitro experiments. This study was designed to compare the relative in vitro susceptibility of each strain of L. intracellularis to different antimicrobials which included metronidazole, minocycline hydrochloride, erythromycin, cephalothin sodium salt, combination (4:1) of sulfamethazine and trimethoprim, chloramphenicol, rifampicin, penicillin, ampicillin, doxycycline hydrochloride, cefazolin sodium salt, clarithromycin, ceftiofur hydrochloride and enrofloxacin. The minimum inhibitory concentration (MIC) was based on intracellular and extracellular activity that inhibited 99% of L. intracellularis growth in cell culture as compared to the antimicrobial-free control. Rifampicin and clarithromycin were the most active antimicrobials against the two L. intracellularis strains tested, with MICs of ≤0.125 when tested both intracellularly and extracellularly. Doxycycline, minocycline, erythromycin, chloramphenicol and enrofloxacin showed intermediate to high activity, and activity was generally higher when evaluating intracellular activity. Sulfamethazine/trimethoprim showed variable results. Ampicillin, penicillin and metronidazole had low to moderate activity. L. intracellularis was resistant to cefazolin, cephalothin and ceftiofur in in vitro conditions. Only two equine isolates of L. intracellularis were available for this study due to the difficulty in isolating this obligate intracellular species from intestinal samples. This is the first report of antimicrobial susceptibility patterns for equine L. intracellularis strains.

Total serum protein reference value as a clinical diagnostic index of equine proliferative enteropathy.

ABSTRACTEquine proliferative enteropathy (EPE) caused by Lawsonia intracellularis is characterized by hypoproteinemia. There are currently no reliable reports that provide a reference value for the total serum protein (TP) concentration to clinically diagnose EPE. The objective of this study was to statistically determine the reference value. Feces and sera of 99 foals with EPE-like clinical signs and of 35 healthy foals were obtained. The samples were used for specific-gene detection of L. intracellularis, TP measurement, and specific-antibody detection against L. intracellularis. Based on these results, the optimal reference value for the TP concentration as a clinical diagnostic index of EPE was found to be ≤ 4.8 g/dl. This clinical diagnostic index will provide an effective approach for diagnosing EPE.

Lawsonia intracellularis in the feces of wild rodents and stray cats captured around equine farms

BackgroundProliferative enteropathy is a global enteric disease of particular importance in pigs. The causative bacterium, Lawsonia intracellularis, has a wide range of susceptible host species. Recently, L. intracellularis has been recognized as an etiologic agent of an emerging enteric disease in foals called equine proliferative enteropathy (EPE). The presence of L. intracellularis in nonruminant wildlife has raised questions regarding the role of these species in EPE transmission.ResultsThis study investigated exposure to L. intracellularis in wild rodents and feral cats from eight farms with confirmed EPE. Serum (42) and fecal (40) samples from resident foals and fecal samples (131), intestinal mucosa tissues (14), and mesenteric lymph nodes (14) from wild and feral animals were collected for the evaluation of the farm status and the molecular detection of L. intracellularis following the diagnosis of EPE in index cases. Fresh feces from wild rodents and feral cats were collected from the ground while walking the premises or after trapping the animals using live traps. A total of 3 brown rats, 7 house mice, 1 striped field mouse, 2 grey red-backed voles, and 3 feral cats showed evidence of prior exposure to L. intracellularis.ConclusionsOur data add to increasing evidence demonstrating the potential for L. intracellularis transmission and infection in wild rodents and feral cats and provide possible evidence of interspecies transmission. The exposure of wild rodents and feral cats provides potential evidence for the spillover of L. intracellularis to wildlife species and raises the question of spillback to horses. Additionally, these animals may represent an indicator of environmental exposure or may be actively involved in the transmission of L. intracellularis to foals by acting as potential reservoir/amplifier hosts. This study is the first to demonstrate the magnitude of L. intracellularis shedding in the feces of wild rodents and feral cats and to indicate the significant infection risk that wild rodents and feral cats pose to naïve horses in South Korea.

Draft Genome Sequence of Lawsonia intracellularis Strain E40504, Isolated from a Horse Diagnosed with Equine Proliferative Enteropathy.

ABSTRACTReported herein is the draft genome sequence of equine-origin Lawsonia intracellularis strain E40504, an obligate intracellular bacterium and the etiological agent of equine proliferative enteropathy. The 1.69-Mb draft genome sequence includes 1,380 protein-coding genes and 49 RNA genes, and it lacks a genomic island reported in swine-origin L. intracellularis strain PHE/MN1-00.

Management of equine proliferative enteropathy

Equine proliferative enteropathy is caused by Lawsonia intracellularis and mainly affects foals that are between two and 13 months of age. The epidemiology is not fully understood, but it is...

Faecal shedding and serological study of Lawsonia intracellularis from two horse farms in Argentina

Lawsonia intracellularis (Li) is the causative agent of equine proliferative enteropathy (EPE), an endemic infection in pigs and an emerging concern in horses. EPE has been reported in North America, Europe, Australia and Brazil, and is more frequent in weaned foals. The antemortem diagnosis of EPE is based on the detection of Liespecific antibodies by serology and the molecular identification of DNA in feces by PCR. The aim of this work is to report an outbreak of EPE in two horse farms in Buenos Aires province. Serology tests were performed both in mares and weanlings (9-12 months) while PCR of faecal samples was performed only in weanlings. The DNA was extracted (ZR MiniPrep Zymo Research, USA) and the PCR was applied according to Jones et al. 1993. The indirect immunofluorescence was carried out according to Knittel et al. 1997. In farm one, sera from 32 mares and two foals with diarrhea and clinical signs were analyzed, while in farm two, sera from 14 mares and 15 foals were processed, where only one had chronic diarrhea and an antibiotic treatment. The results are shown in table 1. Total positive sera were 79% (50/63) and positive PCR in foals 12% (2/17). Besides, at least one animal was positive by PCR in each farm. The high percentage of seropositive animals may indicate previous exposure to Li. The seropositivity of mares implies subclinical infection, a situation of constant exposure or long term persistence of serum antibodies. In a foal with diarrhea and positive PCR may confirm the EPE. However, in a foal with diarrhea and negative PCR, the disease could not ruled out, because a negative result is expected in situations such as a prolonged course or antibiotic therapy. The detection of positive PCR animals without diarrhea, as observed in farm two, can be related to a subclinical infection, a common condition seen in swine. In conclusion, to our knowledge, this is the first description clinical and subclinical case of EPE with confirmed diagnosis by serology and fecal PCR in horses in Argentina. The EPE must be considered among the possible diagnoses in cases of enteritis in foals. Use of these tests may aid in detection of the disease allowing for early and specific treatment to improve the prognosis of affected horses.

Equine proliferative enteropathy on a Brazilian farm

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.

The Possible Role Mares Play in the Epidemiology of Equine Proliferative Enteropathy

The epidemiology of equine proliferative enteropathy (EPE), caused by the bacterium Lawsonia intracellularis, is poorly characterized. It has been suggested that horse-to-horse transmission of the bacterium may be possible, although no work has examined the role mares may play in the epidemiology of EPE. The goal of this study was to determine whether seropositive mares were more likely to have seropositive foals and whether seropositive mares were more likely to have foals with clinical or subclinical EPE. Serum samples were analyzed using an equine enzyme-linked immunosorbent assay for L. intracellularis–specific antibodies. Over 2 years (2012–2013 and 2013–2014), a total of 197 mare and foal pairs from two central Kentucky Thoroughbred farms with endemic EPE participated in this study. All foals were weaned by the end of October of their respective foaling year. There was no overall effect of mare serologic status on the occurrence of presumptive clinical or subclinical EPE in their offspring. Chi-square analysis determined that those mares with five or more seropositive months through October had a significantly higher number of foals with evidence of exposure to the bacterium between July and January (P = .022). Further, mares with less than five seropositive months through October of their foaling year were found to have foals 2.037 times less likely to be seropositive from July through January than those foals from those with five or more seropositive months through October. Additionally, there appeared to be a protective effect of mares on nursing foals with respect to exposure during the summer months.