Diagnostic performance of a rapid immunochromatographic test for the simultaneous detection of antibodies to Theileria equi and Babesia caballi in horses and donkeys

BACKGROUND

Equine piroplasmosis is caused by two tick-borne protozoan parasites, Theileria equi and Babesia caballi,, which are clinically relevant in susceptible horses, donkeys, and mules. Moreover, equine piroplasmosis significantly constrains international trading and equestrian events. Rapidly diagnosing both parasites in carrier animals is essential for implementing effective control measures. Here, a rapid immunochromatographic test for the simultaneous detection of antibodies to T. equi and B. caballi was evaluated using samples from horses and donkeys collected in Greece, Israel, and Italy. The results were compared with an improved competitive enzyme-linked immunosorbent assay (cELISA) for detecting antibodies to both parasites using the same panel of samples.

METHODS

Blood samples were collected from 255 horses and donkeys. The panel consisted of 129 horses sampled at four locations in northern Greece, 105 donkeys sampled at four locations in Sicily, and 21 horses sampled at two locations in Israel. The rapid test and the cELISA were performed according to the manufacturer's instructions, and the results were subjected to a statistical analysis to determine the sensitivity and specificity of both tests and their association.

RESULTS

The immunochromatographic test provided a result within 15 min and can be performed in the field, detecting both pathogens simultaneously. The overall coincidence rate between the rapid test and the cELISA for detecting antibodies against T. equi was 93% and 92.9% for B. caballi. The rapid test's sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for T. equi were above 91.5%. Sixteen samples were positive for both parasites in the rapid test and eight in the cELISA. Either test had no significant association between T. equi and B. caballi detection. The detection rates of both parasites were significantly higher in Italy than in Greece or Israel and in donkeys than in horses. The agreement for T. equi between the results of both tests was high in Greece (93.8%) and Italy (95.2%) and moderate in Israel (76.2%). For B. caballi, the specificity and NPV of the rapid test were high (94.2% and 98.3%, respectively), although the sensitivity and PPV were moderate (69.2% and 39.1%, respectively) due to the small sample size. However, for B. caballi, the sensitivity was higher with the rapid test.

CONCLUSIONS

The rapid test detected T. equi and B. caballi simultaneously in the field, potentially replacing laborious cELISA testing and is recommended for import/export purposes. The test can also be helpful for the differential diagnosis of clinical cases, since seropositivity may rule out equine piroplasmosis since it does not indicate current or active infection.

An Evaluation of the Impact of an OPEN Stewardship Generated Feedback Intervention on Antibiotic Prescribing among Primary Care Veterinarians in Canada and Israel

An interrupted time-series study design was implemented to evaluate the impact of antibiotic stewardship interventions on antibiotic prescribing among veterinarians. A total of 41 veterinarians were enrolled in Canada and Israel and their prescribing data between 2019 and 2021 were obtained. As an intervention, veterinarians periodically received three feedback reports comprising feedback on the participants' antibiotic prescribing and prescribing guidelines. A change in the level and trend of antibiotic prescribing after the administration of the intervention was compared using a multi-level generalized linear mixed-effect negative-binomial model. After the receipt of the first (incidence rate ratios [IRR] = 0.88; 95% confidence interval (CI): 0.79, 0.98), and second (IRR = 0.85; 95% CI: 0.75, 0.97) feedback reports, there was a reduced prescribing rate of total antibiotic when other parameters were held constant. This decline was more pronounced among Israeli veterinarians compared to Canadian veterinarians. When other parameters were held constant, the prescribing of critical antibiotics by Canadian veterinarians decreased by a factor of 0.39 compared to that of Israeli veterinarians. Evidently, antibiotic stewardship interventions can improve antibiotic prescribing in a veterinary setting. The strategy to sustain the effect of feedback reports and the determinants of differences between the two cohorts should be further explored.

Persistence of Anti-Rabies Antibody Response in Horses Following Vaccination

Rabies is a fatal zoonotic disease affecting all mammalian species. It is caused by the rabies virus and is prevalent worldwide. Horses are not commonly infected with rabies but their vaccination is recommended due to the potential zoonotic risk. This study aimed to evaluate the duration of immunity following rabies vaccination in horses. A total of 126 serum samples were collected from 93 horses, vaccinated 6 to 91 months before sampling. Rabies-virus-neutralizing antibody (RVNA) levels were evaluated using the Rabies Fluorescent Focus Inhibition Test (RFFIT). A protective RVNA titer of above 0.5 IU/mL was found in 112 (88.9%) of the samples and 84 (90.3%) of the horses. Antibody titers declined over time (rho = -0.271, p = 0.002); however, there was no significant difference in antibody titers or the prevalence of unprotected horses between the time intervals following vaccination. Purebred horses had lower antibody titers (p = 0.024). The response to booster vaccination was inspected in ten horses, and increased antibody titers were found in eight of them. The results of this study demonstrate the prolonged persistence of protective immunity in horses following rabies vaccination, in some cases, for up to eight years. Therefore, the current annual vaccination strategy should be re-evaluated. A rate of 9.7% of poor responders should be considered from an epidemiological perspective in order to minimize the risk of emergence of the disease.

First Detection of Anti-Besnoitia spp. Antibodies in Equids in Israel and the Palestinian Authority

Besnoitia is a tissue cyst forming coccidia, which affects multiple host species worldwide. Equine besnoitiosis is characterized mainly by generalized skin lesions and cysts in the scleral conjunctiva. Recent reports revealed exposure to Besnoitia in equines in Europe and the United States. However, the exposure to Besnoitia spp. in the Israeli equine population was never investigated. The aim of this study was to evaluate the seroprevalence and associated risk factors for besnoitiosis in equids in Israel. A cross-sectional serosurvey was performed using serum samples of apparently healthy horses (n = 347), donkeys (n = 98), and mules (n = 6), and exposure to Besnoitia spp. was determined by an immunofluorescent antibody test (IFAT). Anti-Besnoitia spp. antibodies were detected in 17.7% equids, 6.9% horses, 33.3% mules, and 55.1% donkeys. The seroprevalence in donkeys was significantly higher than in horses (p < 0.001). A significant association between the geographic location and seropositivity was found both in horses and donkeys, which was significantly higher (p = 0.004) in horses sampled in southern Israel, and donkeys sampled in Israel versus the Palestinian Authority (p < 0.001). This is the first serosurvey of Besnoitia infection in equines in Israel, and the results are consistent with reports from Europe. The clinical significance of equine besnoitiosis should be further investigated.

Detection and Analysis of West Nile Virus Structural Protein Genes in Animal or Bird Samples

West Nile virus (WNV) is an important zoonotic pathogen, which is detected mainly by identification of its RNA using PCR. Genetic differentiation between WNV lineages is usually performed by complete genome sequencing, which is not available in many research and diagnostic laboratories. In this chapter, we describe a protocol for detection and analysis of WNV samples by sequencing the entire region of their structural genes capsid (C), preM/membrane, and envelope. The primary step is the detection of WNV RNA by quantitative PCR of the NS2A gene or the C gene regions. Next, the entire region containing the structural protein genes is amplified by PCR. The primary PCR product is then amplified again in parallel reactions, and these secondary PCR products are sequenced. Finally, bioinformatic analysis enables detection of mutations and classification of the samples of interest. This protocol is designed to be used by any laboratory equipped for endpoint and quantitative PCR. The sequencing can be performed either in-house or outsourced to a third-party service provider. This protocol may therefore be useful for rapid and affordable classification of WNV samples, obviating the need for complete genome sequencing.

West Nile Virus in Common Wild Avian Species in Israel

In order to evaluate the contribution of different wild bird species to West Nile virus (WNV) circulation in Israel, during the months preceding the 2018 outbreak that occurred in Israel, we randomly sampled 136 frozen carcasses of a variety of avian species. Visceral and central nervous system (CNS) tissue pools were tested using WNV NS2A RT qPCR assay; of those, 15 (11.03%, 95% CI: 6.31-17.54%) tissue pools were positive. A total of 13 out of 15 WNV RT qPCR positive samples were successfully sequenced. Phylogenetic analysis indicated that all WNV isolates were identified as lineage 1 and all categorized as cluster 2 eastern European. Our results indicated that WNV isolates that circulated within the surveyed wild birds in spring 2018 were closely related to several of the isolates of the previously reported 2018 outbreak in birds in Israel and that the majority of infected birds were of local species.

West Nile virus neutralizing antibody prevalence in donkeys from northern Nigeria

BACKGROUND

This study aimed to evaluate the prevalence of anti-West Nile virus (WNV) neutralizing antibodies in donkeys from two areas in northern Nigeria.

METHODS

Serology was determined by a virus neutralization test in samples collected from 205 healthy adult donkeys.

RESULTS

Fifty-seven donkeys (27.8%) tested seropositive for WNV. Donkeys from Zaria were 2.6 times more likely to have been exposed to WNV (p<0.001).

CONCLUSION

The results of this study demonstrate that this zoonotic pathogen is prevalent in these areas and that measures should be implemented to reduce the risk for both humans and equids.

Serological and Molecular Prevalence of Babesia caballi in Apparently Healthy Horses in Israel

Babesia caballi is a tick-borne hemoparasite of equines and one of the causative agents of equine piroplasmosis, which poses a great concern for the equine industry regarding animal welfare and international horse movement. The parasite is endemic in Israel; however, its seroprevalence in the area was never evaluated due to antigenic heterogenicity in the gene used in the commercially available kit. Blood samples were collected from 257 horses at 19 farms throughout the country and screened for the presence of anti-B. caballi antibodies via an indirect immunofluorescent antibody test (IFAT) and for the presence of parasite DNA by nested PCR. The seroprevalence of B. caballi was 69.6% and its molecular prevalence was 9.7%. The geographical area, horse’s sex, breed, housing, exposure to ticks, and specifically to Hyalomma marginatum, and co-infection with Theileria equi were found to be significantly associated with serologic exposure in univariable analysis, while the geographical area and horses’ sex remained significant in the multivariable analysis. The results of this study demonstrate a high level of exposure to B. caballi and identify important risk factors for infection. The difference between the serological and molecular prevalence, probably related to parasite clearance, is also highlighted.

Seroprevalence of Leptospira spp. in Horses in Israel

Leptospirosis has been reported in both humans and animals in Israel but has not been reported in horses. In 2018, an outbreak of Leptospira spp. serogroup Pomona was reported in humans and cattle in Israel. In horses, leptospirosis may cause equine recurrent uveitis (ERU). This report describes the first identification of Leptospira serogroup Pomona as the probable cause of ERU in horses in Israel, followed by an epidemiological investigation of equine exposure in the area. Serologic exposure to Leptospira was determined by microscopic agglutination test (MAT) using eight serovars. In 2017, serovar Pomona was identified in a mare with signs of ERU. Seven of thirteen horses from that farm were seropositive for serogroup Pomona, of which three had signs of ERU. During the same time period, 14/70 horses from three other farms were positive for serogroup Pomona. In 2015, two years prior to this diagnosis, 259 horses from 21 farms were sampled and one horse tested seropositive for serovar Icterohaemorrhagiae. In 2018, one year later, 337 horses were sampled on 29 farms, with none testing seropositive. Although horses are not considered a major host of Leptospira spp., it appears that horses may be infected, and clinically affected, in the course of an outbreak in other species. The identification of leptospirosis in stabled horses may impose a significant zoonotic risk to people.

Evaluation of an OPEN Stewardship generated feedback intervention to improve antibiotic prescribing among primary care veterinarians in Ontario, Canada and Israel: protocol for evaluating usability and an interrupted time-series analysis

INTRODUCTION

Antimicrobial resistance (AMR) impacts the health and well-being of animals, affects animal owners both socially and economically, and contributes to AMR at the human and environmental interface. The overuse and/or inappropriate use of antibiotics in animals has been identified as one of the most important drivers of the development of AMR in animals. Effective antibiotic stewardship interventions such as feedback can be adopted in veterinary practices to improve antibiotic prescribing. However, the provision of dedicated financial and technical resources to implement such systems are challenging. The newly developed web-based Online Platform for Expanding Antibiotic Stewardship (OPEN Stewardship) platform aims to automate the generation of feedback reports and facilitate wider adoption of antibiotic stewardship. This paper describes a protocol to evaluate the usability and usefulness of a feedback intervention among veterinarians and assess its impact on individual antibiotic prescribing.

METHODS AND ANALYSIS

Approximately 80 veterinarians from Ontario, Canada and 60 veterinarians from Israel will be voluntarily enrolled in a controlled interrupted time-series study and their monthly antibiotic prescribing data accessed. The study intervention consists of targeted feedback reports generated using the OPEN Stewardship platform. After a 3-month preintervention period, a cohort of veterinarians (treatment cohort, n=120) will receive three feedback reports over the course of 6 months while the remainder of the veterinarians (n=20) will be the control cohort. A survey will be administered among the treatment cohort after each feedback cycle to assess the usability and usefulness of various elements of the feedback report. A multilevel negative-binomial regression analysis of the preintervention and postintervention antibiotic prescribing of the treatment cohort will be performed to evaluate the impact of the intervention.

ETHICS AND DISSEMINATION

Research ethics board approval was obtained at each participating site prior to the recruitment of the veterinarians. The study findings will be disseminated through open-access scientific publications, stakeholder networks and national/international meetings.

Emergence and Spread of Different ESBL-Producing Salmonella enterica Serovars in Hospitalized Horses Sharing a Highly Transferable IncM2 CTX-M-3-Encoding Plasmid

Salmonella enterica is a major causative pathogen of human and animal gastroenteritis. Antibiotic resistant strains have emerged due to the production of extended-spectrum β-lactamases (ESBLs) posing a major health concern. With the increasing reports on ESBL-producing Enterobacterales that colonize companion animals, we aimed to investigate ESBL dissemination among ESBL-producing Salmonella enterica (ESBL-S) in hospitalized horses. We prospectively collected ESBL-S isolates from hospitalized horses in a Veterinary-Teaching Hospital during Dec 2015–Dec 2017. Selection criteria for ESBL-S were white colonies on CHROMagarESBL plates and an ESBL phenotypic confirmation. Salmonella enterica serovars were determined using the Kaufmann-White-Le-Minor serological scheme. ESBL-encoding plasmids were purified, transformed and compared using restriction fragment length polymorphism (RFLP). Whole genome sequencing (Illumina and MinION platforms) were performed for detailed phylogenetic and plasmid analyses. Twelve ESBL-S were included in this study. Molecular investigation and Sequence Read Archive (SRA) meta-analysis revealed the presence of three unique Salmonella enterica serovars, Cerro, Havana and Liverpool, all reported for the first time in horses. PFGE revealed the clonal spread of S. Cerro between seven horses. All twelve isolates carried bla_CTX–M–3 and showed an identical multidrug resistance profile with co-resistance to trimethoprim/sulfamethoxazole and to aminoglycosides. Plasmid RFLP proved the inter-serovar horizontal spread of a single bla_CTX–M–3-encoding plasmid. Complete sequence of a representative plasmid (S. Havana strain 373.3.1), designated pSEIL-3 was a -86.4 Kb IncM2 plasmid, that encoded nine antibiotic resistance genes. pSEIL-3 was virtually identical to pCTX-M3 from Citrobacter freundii, and showed high identity (>95%) to six other bla_CTX–M–3 or bla_NDM–1 IncM2 broad host range plasmids from various Enterobacterales of human origin. Using a specific six gene-based multiplex PCR, we detected pSEIL-3 in various Enterobacterales species that co-colonized the horses’ gut. Together, our findings show the alarming emergence of ESBL-S in hospitalized horses associated with gut shedding and foal morbidity and mortality. We demonstrated the dissemination of CTX-M-3 ESBL among different Salmonella enterica serovars due to transmission of a broad host range plasmid. This report highlights horses as a zoonotic reservoir for ESBL-S, including highly transmissible plasmids that may represent a ‘One-Health’ hazard. This risk calls for the implementation of infection control measures to monitor and control the spread of ESBL-S in hospitalized horses.

Detection of Neospora caninum Infection in Aborted Equine Fetuses in Israel

In horses, Neospora caninum and Neospora hughesi have been associated with fetal loss, and neurological disease, respectively. This study investigated the role of Neospora spp. infection in equine abortion in Israel. The presence of anti-Neospora spp. antibodies was evaluated in 31 aborting mares by indirect fluorescent antibody test (IFAT) and the presence of parasite DNA in their aborted fetuses was evaluated by polymerase chain reaction (PCR), using two target loci (ITS1 and Nc5). The seroprevalence found in aborting mares was 70.9% and the prevalence by DNA detection in the aborted fetuses was 41.9%. Transplacental transmission from positive mares to their fetuses was 45.4% (10/22), while 33.3% (3/9) of fetuses of seronegative mares also tested positive for Neospora. The use of two PCR targets improved the sensitivity of parasite detection, and positive samples were identified by sequence analyses as N. caninum. These finding suggest that N. caninum could be a significant cause of abortion in horses, and that transplacental transmission in horses is an important way of transmission of N.caninum. The results presented here demonstrated the necessity to use several tests concurrently, including serological and molecular assays in order to confirm the involvement of Neospora in mare abortions.

Twenty Years of Equine Piroplasmosis Research: Global Distribution, Molecular Diagnosis, and Phylogeny

Equine piroplasmosis (EP), caused by the hemoparasites Theileria equi, Theileria haneyi, and Babesia caballi, is an important tick-borne disease of equines that is prevalent in most parts of the world. Infection may affect animal welfare and has economic impacts related to limitations in horse transport between endemic and non-endemic regions, reduced performance of sport horses and treatment costs. Here, we analyzed the epidemiological, serological, and molecular diagnostic data published in the last 20 years, and all DNA sequences submitted to GenBank database, to describe the current global prevalence of these parasites. We demonstrate that EP is endemic in most parts of the world, and that it is spreading into more temperate climates. We emphasize the importance of using DNA sequencing and genotyping to monitor the spread of parasites, and point to the necessity of further studies to improve genotypic characterization of newly recognized parasite species and strains, and their linkage to virulence.

Molecular characterization of the re-emerging West Nile virus in avian species and equids in Israel, 2018, and pathological description of the disease

BACKGROUND

In this report we describe the molecular and pathological characteristics of West Nile virus (WNV) infection that occurred during the summer and fall of 2018 in avian species and equines. WNV is reported in Israel since the 1950s, with occasional outbreaks leading to significant morbidity and mortality in birds, high infection in horses and humans, and sporadic fatalities in humans.

METHODS

Animal and avian carcasses in a suitable condition were examined by post-mortem analysis. Tissue samples were examined for WNV by RT-qPCR and the viral load was quantified. Samples with sufficient material quality were further analyzed by Endpoint PCR and sequencing, which was used for phylogenetic analysis. Tissue samples from positive animals were used for culturing the virus in Vero and C6/36 cells.

RESULTS

WNV RNA was detected in one yellow-legged gull (Larus michahellis), two long-eared owls (Asio otus), two domesticated geese (Anser anser), one pheasant (Phasianus colchicus), four hooded crows (Corvus cornix), three horses and one donkey. Pathological and histopathological findings were characteristic of viral infection. Molecular analysis and viral load quantification showed varying degrees of infection, ranging between 70-1.4 × 106 target copies per sample. Phylogenetic analysis of a 906-bp genomic segment showed that all samples belonged to Lineage 1 clade 1a, with the following partition: five samples from 2018 and one sample detected in 2016 were of Cluster 2 Eastern European, two of Cluster 2 Mediterranean and four of Cluster 4. Four of the positive samples was successfully propagated in C6/36 and Vero cell lines for further work.

CONCLUSIONS

WNV is constantly circulating in wild and domesticated birds and animals in Israel, necessitating constant surveillance in birds and equines. At least three WNV strains were circulating in the suspected birds and animals examined. Quantitative analysis showed that the viral load varies significantly between different organs and tissues of the infected animals.

High Exposure to Toxoplasma gondii and Neospora Spp. in Donkeys in Israel: Serological Survey and Case Reports

Simple Summary

Toxoplasma gondii and Neospora spp. are major pathogenic parasites of animals worldwide, with the first also affecting humans. These parasites have two-host life cycles, with the cat and the dog being the definitive hosts of T. gondii and N. caninum, respectively. Both parasites can infect various animal species, as intermediate hosts, in which they form tissue cysts and may cause abortions and neurological disease. Both parasites have been reported in wild and domestic animals in Israel. This study aimed to evaluate the serologic exposure of donkeys to these parasites. A total of 98 donkeys were examined. Half of them (n = 49) were from animal shelters in Israel, and the rest (n = 49) were working donkeys from the Palestinian Authority. Anti-T. gondii antibodies and anti-Neospora spp. antibodies were found in 94% and in 70% of the donkeys, respectively. In addition, two cases of donkeys presenting N. caninum tissue cysts, which were detected during post-mortem examination, were described. This is the first report of the exposure of donkeys to Toxoplasma gondii and Neospora spp. in the area. The exposure of donkeys to both parasites was considerably higher than the exposure of other species in the area and may be the result of poor husbandry conditions and higher exposure to infection. These results indicate that donkeys may have an important role in the maintenance and transmission of these parasites.

Abstract

Toxoplasma gondii and Neospora spp. are closely related cyst-forming coccidian parasites, which infect various animal species and have considerable zoonotic and economic implications, respectively. Both parasites are endemic in Israel and have been reported to infect wild and domestic animals. This study was conceived to evaluate the serologic exposure of donkeys to these parasites. Serum samples were collected from 98 donkeys. Half of them (n = 49) were from animal shelters in Israel, and the rest (n = 49) were working donkeys from the Palestinian Authority. The donkeys were screened for the presence of anti-Toxoplasma and anti-Neospora antibodies by immunofluorescence antibody tests (IFATs). The seroprevalence of T. gondii and Neospora spp. was 94% and 70%, respectively, and 69% of the donkeys were exposed to both parasites. In addition, N. caninum tissue cysts were documented in two donkeys during post-mortem examination. This is the first report of the exposure of donkeys to T. gondii and Neospora spp. in the area. The high prevalence found in this study suggests that donkeys may have a role in the maintenance of these parasites in the area, thus serving as a source of infection for the definitive hosts.

Potential tick vectors for Theileria equi in Israel

Theileria equi Mehlhorn and Schein, 1998 (Piroplasmida: Babesiidae) is an important tick-borne pathogen of horses that is highly endemic in many parts of the world, including Israel. The present study evaluated the potential roles of five hard tick species [Hyalomma excavatum Koch, 1844; Hyalomma marginatum Koch, 1844; Rhipicephalus turanicus Pomerantsev 1936; Rhipicephalus annulatus Say, 1821; Haemaphysalis parva (Neumann, 1897) (all: Ixodida: Ixodidae)], previously found to infest horses in Israel, in acting as vectors for piroplasmosis. For this, DNA was extracted from whole ticks and, when possible, from the salivary glands in each species (n = 10-59). Polymerase chain reaction amplification and sequencing of the 18S rRNA gene were used to detect T. equi in 48 of the 127 ticks (37.8%) and in 21 of the 90 extracted salivary glands (23.3%) in all five species. All but two sequences were classified as T. equi genotype A; the remaining two were classified as genotype D. The findings of this study point to Ha. parva and R. annulatus as potential novel vectors of T. equi, and suggest that parasite genotype selection occurs within the tick vector.

Extended-Spectrum β-Lactamase-Producing Enterobacterales Shedding by Dogs and Cats Hospitalized in an Emergency and Critical Care Department of a Veterinary Teaching Hospital

Extended-spectrum β-lactamase-producing Enterobacterales (ESBL-PE) gut shedding in human medicine is considered as a major reservoir for ESBL-associated infections in high risk patients. In veterinary medicine, data regarding ESBL-PE gut shedding on admission to emergency and critical care department is scarce. We aimed to determine ESBL-PE shedding rates by dogs and cats in this setting and to determine the risk factors for shedding, at two separate periods, three-years apart. Rectal swabs were collected from animals, on admission and 72 h post admission, enriched and plated on Chromagar ESBL plates, followed by bacterial identification. ESBL phenotype was confirmed and antibiotic susceptibility profiles were determined (Vitek 2). Medical records were reviewed for risk factor analysis (SPSS). Overall, 248 animals were sampled, including 108 animals on period I (2015-2016) and 140 animals on period II (2019). In both periods combined, 21.4% of animals shed ESBL-PE on admission, and shedding rates increased significantly during hospitalization (53.7%, p-value < 0.001). The main ESBL-PE species were Escherichia coli and Klebsiella pneumoniae, accounting for more than 85% of the isolates. In a multivariable analysis, previous hospitalization was a risk factor for ESBL-PE gut shedding (p-value = 0.01, Odds ratio = 3.05, 95% Confidence interval 1.28-7.27). Our findings demonstrate significant ESBL-PE gut shedding among small animals in the emergency and critical care department, posing the necessity to design and implement control measures to prevent transmission and optimize antibiotic therapy in this setting.

Infection dynamics of Theileria equi in carrier horses is associated with management and tick exposure

The tick-borne equine hemoparasite, Theileria equi, is endemic in many parts of the world where prevalence may be high, and most infected horses are apparently healthy but serve as life-long carriers. To determine the factors that affect T. equi dynamics, we followed parasitic loads in apparently healthy horses at four time points during one year. A total of 1094 blood samples were collected from 395 horses, along with ticks and demographic and clinical data. Infection and load of T. equi were tested by PCR and qPCR, and for the spring dataset, infection was also tested serologically by IFAT (n = 268). Theileria equi was molecularly detected in 64.8 % of the horses. The agreement between molecular and serological results was 79.8 % (K > 0.674) and positively correlated with parasitic load. Infection was associated with pale mucus membranes, lower packed cell volume and higher total solids (all P < 0.001), although these changes had only minor clinical importance. While parasitic loads in qPCR-positive samples (n = 561) were generally low (mean = 7.9-10^-4% parasitized erythrocytes), younger horses showed higher loads, possibly suggesting development of immunity. Infection and parasitic load were associated with housing management and tick exposure, illustrating different patterns of exposure. Endemic stability is suggested in pasture farms with constant exposure to ticks, where parasite prevalence was high (96 %) and associated with T. equi 18S rRNA genotype D, low parasitemia and high antibody titers. Endemic instability can be suggested in case were horses are kept in paddocks (prevalence = 49 %) with intermittent exposure to ticks, where infection was associated with high parasitemia when ticks were present. A steady state is suggested in stabled horses (prevalence = 46 %), with no exposure to ticks; where infection was associated with genotype A, low parasitemia and low antibody titers. The ability to identify different risk groups within endemic areas may improve the administration of suitable treatment and control practices in an effort to reduce the risk of clinical disease.

Parasite load and genotype are associated with clinical outcome of piroplasm-infected equines in Israel

Background

Equine piroplasmosis is a highly endemic protozoan disease of horses worldwide, caused by Theileria equi and Babesia caballi. While most horses in endemic areas are subclinically infected, the mechanisms leading to clinical outcome are vastly unknown. Moreover, since clinical signs of disease are not specific, and the prevalence in endemic areas is high, it is difficult to determine if equine piroplasmosis is the cause of disease. To identify possible mechanisms leading to the clinical outcome in an endemic area, we compared parasite loads and genotypes in clinically and subclinically infected horses.

Methods

Blood was collected from horses with clinical signs consistent with equine piroplasmosis, and from apparently healthy horses in Israel. Packed cell volume and total solids were measured. Quantitative and diagnostic polymerase chain reaction were used to identify, quantify and classify equine piroplasmosis infection. Phylogenetic analyses were used to determine the genotype of both parasites.

Results

For both parasites, clinical cases were associated with low mean packed cell volume and high mean parasite load (P < 0.001), enabling the determination of a cut-off value to distinguish between clinically and subclinically infected horses. Samples of Theileria equi from subclinical horses were classified into three different 18S rRNA genotypes, D (n = 23), A (n = 12) and C (n = 5), while samples from all clinical cases (n = 6) were classified as genotype A. The sequences of T. equi equi merozoite antigens 1 (ema-1, n = 9) and 2 (ema-2, n = 11) genes were fairly conserved and did not differ between clinical and subclinical cases. Babesia caballi rhoptry associated protein-1 (rap-1) was classified into sub-genotypes A1 (n = 14) and A2 (n = 5) with no association to clinical outcome. Classification of the 18S rRNA gene (sub-genotypes B1 and B2) agreed with the rap-1 classification.

Conclusions

The results of this study suggest that quantification of parasite loads of infected horses may be used to distinguish between infections resulting in disease and subclinical cases. Although number of clinical cases is limited, we identified T. equi 18S rRNA genotype A to be associated with clinical disease. This finding emphasizes the importance of in-depth genetic characterization of T. equi genotypes to identify possible markers for virulence.

Extended-Spectrum β-lactamase-Producing Enterobacteriaceae Shedding in Farm Horses Versus Hospitalized Horses: Prevalence and Risk Factors

Simple summary

This prospective study investigated the prevalence, molecular characteristics and risk factors of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-E) shedding in three equine cohorts: (i) farm horses (13 farms, n = 192); (ii) on admission to a hospital (n = 168) and; (iii) horses hospitalized for ≥72 h re-sampled from cohort (ii) (n = 86). Bacteria were isolated from rectal swabs, identified, antibiotic susceptibility patterns were determined, and medical records and owners’ questionnaires were analyzed for risk factor analysis. ESBL shedding rates significantly increased during hospitalization (77.9%, n = 67/86), compared to farms (20.8%, n = 40/192), and horses on admission (19.6%, n = 33/168). High bacterial species diversity was identified, mainly in cohorts (ii) and (iii), with high resistance rates to commonly used antimicrobials. Risk factors for shedding in farms included horses’ breed (Arabian), sex (stallion), and antibiotic treatment. Older age was identified as a protective factor. We demonstrated a reservoir for antibiotic-resistant bacteria in an equine hospital and farms, with a significant ESBL-E acquisition. In light of our findings, in order to control ESBL spread, we recommend conducting active ESBL surveillance programs alongside antibiotic stewardship programs in equine facilities.

Abstract

We aimed to investigate the prevalence, molecular characteristics and risk factors of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-E) shedding in horses. A prospective study included three cohorts: (i) farm horses (13 farms, n = 192); (ii) on hospital admission (n = 168) and; (iii) horses hospitalized for ≥72 h re-sampled from cohort (ii) (n = 86). Enriched rectal swabs were plated, ESBL-production was confirmed (Clinical and Laboratory Standards Institute (CLSI)) and genes were identified (polymerase chain reaction (PCR)). Identification and antibiotic susceptibility were determined (Vitek-2). Medical records and owners’ questionnaires were analyzed. Shedding rates increased from 19.6% (n = 33/168) on admission to 77.9% (n = 67/86) during hospitalization (p < 0.0001, odds ratio (OR) = 12.12). Shedding rate in farms was 20.8% (n = 40/192), significantly lower compared to hospitalized horses (p < 0.0001). The main ESBL-E species (n = 192 isolates) were E. coli (59.9%, 115/192), Enterobacter sp. (17.7%, 34/192) and Klebsiella pneumoniae (13.0%, 25/192). The main gene group was CTX-M-1 (56.8%). A significant increase in resistance rates to chloramphenicol, enrofloxacin, gentamicin, nitrofurantoin, and trimethoprim-sulpha was identified during hospitalization. Risk factors for shedding in farms included breed (Arabian, OR = 3.9), sex (stallion, OR = 3.4), and antibiotic treatment (OR = 9.8). Older age was identified as a protective factor (OR = 0.88). We demonstrated an ESBL-E reservoir in equine cohorts, with a significant ESBL-E acquisition, which increases the necessity to implement active surveillance and antibiotic stewardship programs.

Stress conditions do not affect Theileria equi parasitemia levels in sub-clinically infected horses

Stress has been suggested as a risk factor for Theileria equi peracute disease and may lead to relapse in clinical signs in chronically infected horses. The aim of this study was to assess the effect of stress on T. equi parasitemia in sub-clinically infected horses in two settings: horses hospitalized at a veterinary teaching hospital and horses from an endurance farm. Blood samples were collected from the hospitalized horses (n = 32) upon admission (T0) and at discharge (T1) from the hospital, and results were compared between horses that underwent surgery (stress) and other hospitalized horses (control). Blood samples were collected from an endurance farm (n = 20) six weeks before (T0) and two days after (T1) participation in an 80-km endurance event, and results were compared between horses that participated (stress) or did not participate (control) in the event. Theileria equi parasite load was determined using qPCR, and T1/T0 ratio was calculated for each horse. Mean parasite load at both time points did not differ statistically between the stress group and the controls in both settings. Theileria equi genotype was determined based on the 18S rRNA gene, when possible. Parasite genotypes were similar to strains previously characterized in the region and classified as genotypes A and D. The results of this study contradict the common assumption that stress may lead to increased parasite load in horses with a subclinical T. equi infection.

Petting Zoo Animals as an Emerging Reservoir of Extended-Spectrum β-Lactamase and AmpC-Producing Enterobacteriaceae

Extended spectrum beta-lactamases and AmpC-producing Enterobacteriaceae (ESBL/AmpC-E) have become a great concern in both human and veterinary medicine. One setting in which this risk could be particularly prominent is petting zoos, in which humans, especially children, directly and indirectly interact with the animals. Yet, while the zoonotic transmission of various Enterobacteriaceae has been reported previously in petting zoos, reports on ESBL/AmpC-E shedding in this setting is currently lacking, despite the high potential risk. To fill this knowledge gap, we conducted a prospective cross-sectional study to explore the prevalence, molecular epidemiology, and risk for shedding of ESBL/AmpC-E in petting zoos. We performed a prospective cross-sectional study in eight petting zoos. Altogether, we collected 381 fecal and body-surface samples from 228 animals, broth-enriched them, and then plated them onto CHROMagar ESBL-plates for ESBL/AmpC-E isolation. Next, we identified the isolated species and tested their susceptibility to various antibiotics using the Vitek-2 system, determined bacterial relatedness by multilocus sequence typing (MLST), and identified ESBL/AmpC genes by using PCR and sequencing. Finally, we asked petting zoo owners and veterinarians to complete questionnaires, which we then analyzed to evaluate risk factors for ESBL/AmpC-E shedding. We found that ESBL/AmpC-E shedding is an important, currently oversighted risk in petting zoos, as the overall shedding rate was 12% (35 isolates, including 29% ESBL-producers, 34% AmpC-producers, and 37% ESBL and AmpC-producers). The isolated bacteria included Enterobacter cloacae (55%), Escherichia coli (31%), and Citrobacter freundii (14%), with diverse ESBL genes. MLST revealed diverse sequence types (STs), including the highly virulent Enterotoxigenic ST656 and the Uropathogenic ST127 E. coli strains, indicating complex epidemiology with inter-animal bacterial transmission. Shedding was associated with petting permission and antibiotic treatment in the petting zoo (OR = 7.34), which were identified as risk factors for ESBL/AmpC shedding. Our findings highlight petting zoos as a source for antibiotic-resistant ESBL/AmpC-producing bacteria, including highly virulent, disease-associated MDR E. coli strains. As this risk has not been previously described in detail, it calls for the implementation of infection control and active surveillance programs in petting zoos and raises the need for a comprehensive guideline to restrain this emerging concern.

Genetic characteristics of Theileria equi in zebras, wild and domestic donkeys in Israel and the Palestinian Authority

Equine piroplasmosis (EP) is an important tick-borne disease of equids, caused by Theileria equi and Babesia caballi. It is endemic in most parts of the world, including Israel, and has clinical and economic consequences. This study was set to evaluate the presence of EP parasites in domestic donkeys and in wild equids in Israel and the Palestinian Authority (PA). To assess subclinical EP infection in 98 domestic donkeys (Equus africanus asinus), 9 Asiatic wild donkeys (Equus hemionus), 8 zebras (Equus quagga), 7 African wild donkeys (Equus africanus) and 5 mules, were tested using PCR and qPCR. Positive samples were characterized by amplification and sequencing of a 1600 bp fragment of the 18S rRNA gene. Babesia caballi was not detected in any of the animals. Theileria equi was detected in 32% of the donkeys, 89% of Asiatic wild donkeys, 57% of African wild donkeys, 62% of zebras and none of the mules. Parasitemia was low in all of the positive samples. Risk factors associated with infection in donkeys included one farm (Kiryat Gat) and animal sex (male). The sequences of the 18S rRNA gene from domestic donkeys were all similar, and belonged to the T. equi genotype D, similar to the genotype sequenced from horses in the same area, while sequences from wild donkeys were unique and belonged to the T. equi genotype A. Verification of the T. equi genotype in zebras could not be concluded, suggesting major genetic variation.

Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae in Hospitalized Neonatal Foals: Prevalence, Risk Factors for Shedding and Association with Infection

Simple Summary

Multidrug-resistant (MDR) Enterobacteriaceae are becoming a major worldwide concern in human and veterinary medicine, mainly due to the production of extended-spectrum β-lactamases (ESBLs). These bacteria have been investigated in adult horses, but not in neonatal foals. In this study, we investigated extended-spectrum β-lactamase Enterobacteriaceae (ESBL-E) shedding and infection in hospitalized mares and their neonatal foals. Overall, we sampled rectal swabs from 55 pairs of mares and their foals on admission, and 33 of them were re-sampled on the 3rd day of hospitalization. We also collected clinical samples, when available. We found that shedding rates and bacterial species diversity increased significantly during hospitalization, both in mares and foals. On admission to hospital, foals’ shedding was associated with umbilical infection. During hospitalization, it was associated with ampicillin treatment. Foals’ shedding was independent of their mares’ shedding. Four foals were infected with ESBL-E strains, including umbilical infections and wounds. We suggest further investigation and surveillance of ESBL-E in neonatal foals, in order to reduce resistance rates and infections.

Abstract

Extended-spectrum β-lactamase Enterobacteriaceae (ESBL-E) have been investigated in adult horses, but not in foals. We aimed to determine shedding and infection in neonatal foals and mares. Rectal swabs were sampled from mare and foal pairs on admission and on the 3rd day of hospitalization; enriched, plated, and bacteria were verified for ESBL production. Identification and antibiotic susceptibility profiles were determined (Vitek2). Genotyping was performed by multilocus sequence typing (MLST). Genes were identified by PCR and Sanger sequencing. Medical data were analyzed for risk factors (SPSS). On admission, 55 pairs were sampled, of which 33 pairs were re-sampled. Shedding rates on admission in foals and mares were 33% (95% CI 21–47%) and 16% (95% CI 8–29%), respectively, and during hospitalization, these increased significantly to 85% (95% CI 70–94%) and 58% (95% CI 40–73%), respectively. Foal shedding was associated with umbilical infection on admission (P = 0.016) and with ampicillin treatment during hospitalization (p = 0.011), and was independent of the mare’s shedding. The most common ESBL-E was Escherichia coli. During hospitalization, species diversity increased. Four foals were infected with ESBL-E strains, including umbilical infections and wounds. This study substantiates an alarming prevalence of shedding in neonatal foals, which should be further investigated in order to reduce resistance rates.

Comparison of three acute colic pain scales: Reliability, validity and usability

A valid, reliable and usable scale is needed for assessing severity of acute abdominal pain in horses. The study aim was to compare three different scales: (1) the equine acute abdominal pain scale (EAAPS); (2) a scale described by Mair and Smith (2005; M and S); and (3) a numerical rating scale (NRS). Forty brief films of horses (35 of colic cases and five of control horses) were randomly presented to 46 equine veterinarians from different countries. Participants, randomly divided into three groups, each used one scale. Five randomly selected films were shown twice for determining intra-observer reliability. Speed, ease of use and face validity of the scales were evaluated based on expert opinion. Response rate was excellent: 89% for the EAAPS (16/18), and 100% for the M and S (18/18) and NRS groups (10/10). The intraclass correlation (ICC) of 0.86 [95% confidence interval (CI); 0.80-0.92] for EAAPS indicated significantly better inter-observer reliability compared to 0.68 for the M and S and 0.71 for the NRS. Moreover, intra-observer reliability of EAAPS (weighted κ 0.95 [95%CI; 0.92-0.98]) was superior to the other scales (weighted κ 0.78, 0.77, for the M and S and NRS, respectively). Other validity measures (convergent, extreme group, predictive validities), usability (time taken to score the films-speed) and the ease of use of the scales were not significantly different. Face validity (endorsement by experts) was better for the M and S scale than for the EAAPS. The EAAPS showed superior reliability, the M and S scale better face validity, with comparable usability and other tests of validity.

Species distribution and seasonal dynamics of equine tick infestation in two Mediterranean climate niches in Israel

Background

Ticks are important ectoparasites of horses that can affect animal welfare and vector several infectious, including zoonotic, diseases. In order to investigate the species distribution, epidemiology and seasonal dynamics of ticks infesting horses in Israel, 3267 ticks were collected from 396 horses in 24 farms across the country from July 2014 to June 2015.

Results

Ticks were found on 50% of the farms and on 25% of the horses, with Hyalomma being the most prevalent genus (70% of ticks). Pasture was the most prominent risk factor for tick infestation (99% of ticks, P < 0.001), and is represented here by two areas with a Mediterranean climate that differ in their environmental characteristics: the Golan Heights (GH, 74% of ticks); and the Carmel mountain ridge (CMR, 24%). Although these two sites are less than 100 km apart, the composition of the tick populations infesting horses differed significantly between them. In GH the most abundant tick species was Hyalomma excavatum (P < 0.001), while in CMR it was Hyalomma marginatum (P < 0.001). The GH also hosted a more diverse tick fauna than the CMR, including Haemaphysalis parva (peaking in the autumn, P < 0.001) and Rhipicephalus turanicus (peaking in the spring, P < 0.001), which were not found at the other sites. A few Rhipicephalus bursa, Hyalomma rufipes and Hyalomma turanicum were also found on horses.

Conclusions

The current findings can be used in epidemiological studies assessing the risk of tick-borne equine diseases in the area. Further analysis is needed to determine the specific distribution and habitat preferences of each tick species.

Electronic supplementary material

The online version of this article (10.1186/s13071-018-3093-0) contains supplementary material, which is available to authorized users.

Post-partum concentrations of serum progesterone, oestradiol and prolactin in Arabian mares demonstrating normal maternal behaviour and Arabian mares demonstrating foal rejection behaviour

The aim of this prospective study was to investigate possible endocrine components to foal rejection behaviour in post-partum Arabian mares. Arabian mares were divided into two groups based on their maternal behaviour: (1) mares with normal post-parturient behaviour (8 mares); and (2) mares that demonstrated foal-rejecting behaviour post-partum (15 mares). Most mares were visited and sampled twice, in the first and third days post-partum. Serum samples were used for measurement of progesterone, oestradiol and prolactin concentrations. There were no statistically significant differences in oestradiol, progesterone or prolactin concentrations between the groups. In the rejecting mares, there was a statistically significant decrease in the progesterone (mean±standard deviation, SD, 3.14±6.2ng/dL on day 1 and 0.49±0.18ng/dL on day 3) and prolactin (mean±SD 216.2±325.4ng/mL on day 1 and 145.2±311.4ng/mL on day 3) concentrations between days 1 and 3, while the oestradiol concentration did not change significantly. In the non-rejecting mares, progesterone concentrations decreased significantly (mean±SD 0.8±0.23ng/dL on day 1 and 0.43±0.22 on day 3) while the oestradiol and prolactin concentrations did not change significantly. The oestradiol to progesterone ratio was significantly higher in non-rejecting mares on day 1 (mean±SD 114.8±140.2 on day 1 and 143.4±72.6 on day 3) and this ratio increased significantly from days 1 to 3 in the rejecting mares (mean±SD 47.3±21.1 on day 1 and 122.1±123.7 on day 3).

Seroprevalence and risk factor analysis for exposure to equine encephalosis virus in Israel, Palestine and Jordan

Equine encephalosis virus (EEV) is an orbivirus transmitted by Culicoides species. Most infected horses show mild clinical signs and mortality is usually very low. EEV is closely related and similarly transmitted to other, more pathogenic and economically important, orbiviruses such as African horse sickness virus (AHSV), bluetongue virus (BTV) and epizootic haemorrhagic disease viruses (EHDV), and may serve as an indicator for possible transmission of the latter. Israel has been reported to be endemic for EEV since 2001. This study was initiated to re‐evaluate the current seroprevalence and risk factors for EEV exposure in Israel, and to assess, for the first time, the seroprevalence of EEV in Palestine and Jordan. Three hundred and sixteen serum samples were collected from apparently healthy horses at 21 farms in Israel, 66 horses at nine farms in Palestine and 100 horses at three farms in Jordan. The presence of EEV antibodies was detected by a serum neutralization assay. Seroprevalence of EEV was 58.2% (184/316 horses) in Israel, 48.5% (32/66 horses) in Palestine and 2% (2/100 horses) in Jordan. Seroprevalence in Jordan was significantly lower than in Israel and Palestine (P < 0.001). The farm (P < 0.001) and horse age (P = 0.003) were found as significant risk factors for EEV exposure in Israel in multivariable statistical analysis. The results of this study further demonstrate that EEV is no longer limited to South Africa and is endemic in both Israel and Palestine and horses in Jordan were also exposed to this virus emphasizing the potential of pathogens to invade new ecological niches.

Daboia (Vipera) palaestinae envenomation in horses: Clinical and hematological signs, risk factors for mortality and construction of a novel severity scoring system

Daboia palaestinae is the most common venomous snake in Israel and an important cause of envenomations in humans and animals. Although specific antivenom is produced from horses, little documentation exists regarding the characteristics of envenomed horses. This survey was constructed to describe the clinical, hematological and biochemical characteristics of D. palaestinae envenomation in horses, to identify risk factors for fatality and to construct a prognostic snakebite severity scale (SSS) to be used by veterinarians in the field. Data regarding 123 equine snakebite cases were collected over four years. Clinical signs most frequently described were local swelling (100%), tachycardia (67%), increased respiratory effort (62%), bite marks (44%) and reduced appetite (50%). Blood samples were collected at initial presentation from 23 of these horses. Hematological and biochemical abnormalities described in the majority of the sampled cases included leukocytosis (52%), neutrophilia (78%), increased creatine phosphokinase (77%), hypoproteinemia (50%), decreased total carbon dioxide (54%), and hyperphosphatemia (54%). The overall case fatality rate was 20.3% (25/123 horses). Risk factors associated with increased mortality (P < 0.05) were body weight below 200 kg, hind limb envenomation, severity of local swelling, mental status, respiratory effort, bleeding disorders, dehydration, basophilia, monocytosis, bilirubinemia, hypocalcemia and hyperphosphatemia. These risk factors were used to construct an SSS adapted for the assessment of envenomed horses in the field, consisting of seven dichotomous parameters. A cutoff value of 1.5 predicted mortality with 95% sensitivity and 68% specificity. In the future, this tool could assist clinicians with case management and communication with owners.

Seroprevalence of Rhodococcus equi in horses in Israel

Rhodococcus equi is a common cause of pneumonia in foals and has extensive clinical, economic and possibly zoonotic consequences. This bacterium survives well in the environment and may be considered as normal flora of adult horses. Certain strains of this bacterium are extremely virulent in foals, and early identification and intervention is crucial for prognosis. Rhodococcus equi is endemic in many parts of the world and occasionally isolated in Israel. This study was designed to evaluate R. equi seroprevalence in adult horses in Israel to indirectly indicate the potential level of exposure of susceptible foals. Sera were collected from 144 horses during spring 2011 and from 293 horses during fall 2014, and the presence of antibodies against virulent R. equi was detected by enzyme-linked immunosorbent assay. Equine seroprevalence of R. equi was found to be 7.6% in 2011 and 5.1% in 2014. Only one farm had seropositive horses in 2011, whereas several farms had seropositive horses in 2014. No significant risk factors for seropositivity were found. Rhodococcus equi appears to be endemic in Israel. This is the first survey of R. equi in Israel that provides information on the epidemiology of this important bacterium.

West Nile Virus: Seroprevalence in Animals in Palestine and Israel

West Nile virus (WNV) epidemiological situation in Israel and Palestine, due to their unique location, draws attention following to the global spread of West Nile fever (WNF). Although much information is available from Israel on clinical cases and prevalence of WNV, clinical cases are rarely reported in Palestine, and prevalence is not known. The objectives of this study were to determine WNV seroprevalence in various domestic animals in Palestine and to reevaluate current seroprevalence, force of infection, and risk factors for WNV exposure in horses in Israel. Sera samples were collected from 717 animals from Palestine and Israel (460 horses, 124 donkeys, 3 mules, 50 goats, 45 sheep, and 35 camels). Two hundred and ten horses were sampled twice. The level of WNV antibodies was determined using commercial Enzyme-linked Immunosorbent Assay (ELISA) Kit. Seroprevalence in equids was 73%. Seroprevalence in Israel (84.6%) was significantly higher than in Palestine (48.6%). Seroprevalence in horses (82.6%) was significantly higher than in donkeys and mules (39.3%). Multivariable statistical analysis showed that geographical area, landscape features (altitude), environmental factors (land surface temperature during the day [LSTD]), species, and age significantly influenced WNV seroprevalence. Fourteen of 95 (14.7%) sheep and goats and 14/35 camels (40%) sampled in Palestine were seropositive for WNV. Of the horses that were sampled twice, 82.8% were seropositive for WNV at the first sampling, and all remained seropositive. Three of the seronegative horses, all from Palestine, converted to positive when resampled (8.5%). The results indicate that domestic animals in Palestine were infected with WNV in the past, and the seroconversion indicates that WNV was circulating in Palestine in the summer of 2014. Control measures to prevent human infection should be implemented in Palestine. Anti WNV antibodies in domestic animals suggest that those species can be used as sentinels for WNV activity in areas where most horses are either seropositive or vaccinated.

Streptococcus equi subspecies equi in horses in Israel: seroprevalence and strain types

The purpose of this cross-sectional study was to determine the seroprevalence of Streptococcus equi in Israel, to monitor seropositive horses over time and to identify archived strains that were recovered from Israeli horses. A serological survey of 200 healthy horses on 20 farms throughout Israel was performed to detect recent exposure to S equi antigens A and C via indirect ELISA. Seroprevalence was 9.5 per cent (19/200) and positive horses were found in 30 per cent (6/20) of the farms. Sixteen horses that returned a positive serology result were retested three and six months later. Most (12/16) positive horses remained positive, which suggests the presence of animals with persistent infection. Molecular characterisation of S equi strains by sequencing of the SeM gene of 16 archived isolates of S equi that were recovered from clinical cases of strangles between 2008 and 2012 identified two strains: SeM-2 and SeM-28.

Spatial and temporal distribution of West Nile virus in horses in Israel (1997-2013)--from endemic to epidemics

With the rapid global spread of West Nile virus (WNV) and the endemic state it has acquired in new geographical areas, we hereby bring a thorough serological investigation of WNV in horses in a longstanding endemic region, such as Israel. This study evaluates the environmental and demographic risk factors for WNV infection in horses and suggests possible factors associated with the transition from endemic to epidemic state. West Nile virus seroprevalence in horses in Israel was determined throughout a period of more than a decade, before (1997) and after (2002 and 2013) the massive West Nile fever outbreak in humans and horses in 2000. An increase in seroprevalence was observed, from 39% (113/290) in 1997 to 66.1% (547/827) in 2002 and 85.5% (153/179) in 2013, with persistent significantly higher seroprevalence in horses situated along the Great Rift Valley (GRV) area, the major birds' migration route in Israel. Demographic risk factors included age and breed of the horse. Significantly lower spring precipitation was observed during years with increased human incidence rate that occurred between 1997–2007. Hence, we suggest referring to Israel as two WNV distinct epidemiological regions; an endemic region along the birds' migration route (GRV) and the rest of the country which perhaps suffers from cyclic epidemics. In addition, weather conditions, such as periods of spring drought, might be associated with the transition from endemic state to epidemic state of WNV.

Molecular characterization of the Babesia caballi rap-1 gene and epidemiological survey in horses in Israel

Equine piroplasmosis imposes great concerns for the equine industry regarding international horse movement, and therefore requires reliable diagnostic tools. Recent studies from South Africa and Jordan, including a preliminary study in Israel, reported extremely low seroprevalence to Babesia caballi (B. caballi) (0-1%) using the acceptable rhoptry-associated protein-1 (RAP-1) cELISA. In accordance with the study from South Africa demonstrating a significant heterogeneity in the rap-1 gene sequence of South African B. caballi isolates, the objectives of this study were to phylogenetically characterize the rap-1 gene of the Israeli isolates and determine the prevalence of B. caballi in horses in Israel. Out of 273 horses tested using the RAP-1 cELISA, only one was sero-positive, while 9.3% were positive on PCR performed on the rap-1 gene. Phylogenetic analysis of the rap-1 gene grouped the Israeli isolates in a cluster together with the South African strains (99% nt identity), but in a separate cluster from the American/Caribbean strains (81-82% nt identity). These findings support the existence of heterogeneity in the RAP-1 amino-acid sequences of the Israeli and South African isolates as compared to that used in the cELISA commercial kit and raise doubts as to the ability of this assay to serve as a sole regulatory test for international horse movement. Risk factor analysis found management and age to significantly associate with prevalence of B. caballi, as higher prevalence was noted in horses held out on pasture and a negative association was recorded with age. In addition, B. caballi was not detected in horses in the steppe-arid and extreme-arid climatic regions as compared to the wetter regions. Findings of this study emphasize the need to combine several detection methods to ameliorate the control and spread of the disease.

Successful medical management of intra-abdominal abscesses in 4 adult horses

Four adult horses with large intra-abdominal abscesses, suspected to be complications of strangles, were treated with systemic antibiotics alone and made a full recovery. The 100% survival rate is significantly better than other reported survival rates. The median duration of treatment (35 days) was shorter than in most previous reports. This study suggests that penicillin G can be used for successful treatment of strangles associated intra-abdominal abscesses in horses.

Isolation and phylogenetic grouping of equine encephalosis virus in Israel

During 2008–2009 in Israel, equine encephalosis virus (EEV) caused febrile outbreaks in horses. Phylogenetic analysis of segment 10 of the virus strains showed that they form a new cluster; analysis of segment 2 showed ≈92% sequence identity to EEV-3, the reference isolate. Thus, the source of this emerging EEV remains uncertain.