Horses In Brazil Research Articles

Clinical and epidemiological aspects in equine aural plaques.

The association between aural plaques, Equus caballus papillomavirus (EcPV), and the different breeds of horses and risk factors is poorly described. The objective of this study was to determine the clinical prevalence of aural plaques in Mangalarga Marchador (MM) and Quarter Horse (QH) horses in Brazil, to evaluate the association of this prevalence with some risk factors, and to detect the presence of EcPV DNA (types 1-10) in aural plaques biopsies. A total of 400 MM and 425 QH horses, were clinically evaluated. For each horse, an identification form was completed, containing information on breeding, sex, age, presence, and classification of aural plaque lesions, presence of ectoparasites, management type, ear clipping performed, and sensitivity to ear palpation. Biopsies of the lesions were taken from 30 horses and assessed for the presence of EcPV DNA using PCR. Among the MM and QH horses evaluated, 41.5% and 33.6%, respectively, had aural plaques. The MM horses showed a higher frequency of plaques than QH (p = 0.02). At least one viral type was identified in 90% of all aural plaque biopsies, with EcPV4 being the most frequently detected in both breeds, followed by EcPV6, EcVP5, EcVP3 and EcPV1 respectively. In one sample, EcPV1 was detected alone, although it had previously been described only in copresence. The copresence of viral DNA the MM 73% (11/15) QH 27% (4/15) horses. Aural plaques are widely distributed, with a higher prevalence of EcPV4. Additionally, MM horses have higher susceptibility and frequency of the disease than QH horses.

OCORRÊNCIA DA FEBRE DO NILO EM EQUINOS NO BRASIL

West Nile Fever (WNF) is a zoonotic arbovirus caused by the West Nile Virus (WNV). It is a highly relevant topic in veterinary medicine in Brazil. It was first identified in Uganda in 1937 and the virus spread to Africa, Europe, the Middle East, Western Asia and Australia. In 1999, the virus reached the United States and has since spread throughout the Americas, becoming the arbovirus with the largest geographic distribution. The first signs of WNV in Brazil appeared in 1999, with positive results in birds and horses, with birds acting as sentinels for the disease. In 2014, the first human case was recorded in Piauí. As of 2018, cases in birds and horses have been confirmed in Espírito Santo. WNV, an RNA virus of the Flaviviridae family, is transmitted by the bite of mosquitoes of the Culex genus, and these mosquitoes become infected through infected birds during the viremic period. Birds are amplifying hosts and humans and horses are accidental hosts. In Brazil, climatic, environmental and socioeconomic characteristics contribute to the amplification of the virus. Diagnosis is made by demonstrating antiviral IgM by ELISA, or, post-mortem, with RT-PCR. Preventive measures involve the use of repellents and screens, in addition to the application of larvicides. In horses, the application of vaccines, although recommended, is not yet licensed in Brazil. This study analyzed the occurrence of West Nile Fever in horses in Brazil through a review of scientific articles. Searches were conducted in the Google Scholar, PUBMED and Scielo databases, published between 2004 and 2024. The research was supported by the following search criteria: “Nile Fever”, “equines” and “Brazil”, in Portuguese, and “West Nile Fever”, “horses” and “Brazil”, in English. It was found that horses are accidental or terminal hosts and, because it is little known, many times it is not reported or diagnosed, thus demonstrating the importance of further studies and dissemination of information about this disease.

The Weight of Genetic Drift: A Pedigree-Based Evaluation of the Breton Horse Population in Brazil.

The genetic diversity of Breton horses in Brazil is a critical concern, mainly due to the small population size and low number of births per year. Given that the inbreeding was overlooked by breeders for multiple generations, we estimated the genetic diversity of this population utilizing pedigree-based measures of population diversity. A total of 1394 six-generation pedigrees representing the full population of registered Breton horses in Brazil defined a total population (TP, N = 2679), with horses born between 2000 and 2022, reproductively active and alive, as reported by the breed association, representing the reference population (RP, N = 731). Using the R package PurgeR, we estimated inbreeding coefficient (F ped ), maternal inbreeding coefficient (F da m ), paternal inbreeding coefficient (F sire ), individual reproductive values, number of equivalents to complete generations (t), and unbiased ancestral inbreeding coefficient (Fa). We established the equivalent complete generations (ECG), effective population size (Ne), total number of founders (Nf), effective number of founders (Nfe), total number of ancestors (Na), effective number of ancestors (Nae), founder genomes (Ng), and the inbreeding coefficient estimated with effective population size (Ne) and generation numbers (t) (F Ne:t ), as well as Nfe/Nae and Nfe/Ng ratios for the RP. The RP inbreeding levels have stabilized, although they are still significantly rising by generation (t), and the Nfe/Ng ratio strongly suggests genetic drift. Pedigree-based analysis demonstrates that only five stallions have sired 52.83% of the RP individuals, which along with the Nae value of 36.73 implies that the observed inbreeding can be arising from patrilines. Our results suggest that observed inbreeding is due to Popular Sire Effect, highlighting the importance of monitoring breeding schemes and genetic diversity to maintain health.

Knowledge and practice of radiation safety in Brazilian equine veterinarians are less than optimal: An online survey.

Exposure to ionizing radiation is an occupational risk for veterinarians due to the potential for carcinogenesis, reproductive disorders, cataracts, and hereditary genetic changes. This survey study aimed to identify the radiological protection practices routinely used by veterinarians who work with portable digital X-ray equipment in horses in Brazil and assess their knowledge regarding current legislation. A total of 120 voluntary participation questionnaires were sent to veterinarians who used portable digital radiographic equipment in horses nationwide. The frequencies of the answers were analyzed using the chi-square test and logistic regression models. Thirty-five veterinarians responded (29% response rate). Of these, there was a greater participation of professionals in public institutions (40%, 14/35, p<.001), with 69% from the southeast region (24/35, p<.001) and 69% (24/35, p=.028) being male. We found that self-employed veterinarians had a higher odds ratio (OR) (9.00; 95% confidence interval (CI) [1.39-58.44]; p=.021) of not using personal protective equipment compared with those in professional public institutions. In addition, not knowing the current legislation Collegiate Directorate Resolution 611/22 was a potential risk factor for lower radiological protection (OR, 8.00; 95% CI, [0.79-81.33]; p=0.079). In conclusion, findings indicated that Brazilian equine veterinarians generally do not adopt adequate radiological protection against ionizing radiation during radiographic examinations and have low knowledge of the current legislation. Results can be used as background for the formulation of specific radiation protection guidelines for veterinarians and incentive educational and training strategies to reduce risks inherent to occupational exposure.

Racing Performance of the Quarter Horse: Genetic Parameters, Trends and Correlation for Earnings, Best Time and Time Class.

The aim of this study was to evaluate the sprint racing performance of Quarter Horses in Brazil. Estimating genetic parameters, trends and correlations were obtained by single- and two-trait analyses using Bayesian inference (earnings to 2 years of equestrian age, best time and time class at distances of 301 m and 402 m). The data comprised a period of 38 equestrian years (1978 to 2015) with 23,482 sprint race records from 5861 animals. The heritability estimates were of low to moderate magnitude, ranging from 0.10 to 0.37 (single-trait) and from 0.15 to 0.41 (two-traits), and the repeatability was 0.31 to 0.46. The additive, residual and phenotypic correlations between earnings to 2 years of equestrian age and the other traits (best time and time class in distances 301 m and 402 m) were high (-0.95, -0.96, 0.69 and 0.92), low (-0.29, -0.37, 0.26 and 0.27) and moderate (-0.41, -0.47, 0.37 and 0.47), respectively. There is a positive genetic trend for all traits considered. However, evaluation of the last 10 equestrian years (2006 to 2015) showed negative trends (genetic loss) and trends close to zero (genetic stagnation). The design of breeding programs using the earnings trait in conjunction with other racing performance traits can enhance changes in the genetic gains as a whole in speed-racing Quarter Horses. These findings suggest that the traits studied should be included in breeding selection programs for racing Quarter Horses.

Reactivity against Sarcocystis neurona and Sarcocystis falcatula-like in horses from Southeastern and Midwestern Brazil.

Equine protozoal myeloencephalitis (EPM) is a neurological disease caused by Sarcocystis neurona. Immunofluorescence antibody tests (IFATs) have been widely used to identify exposure of horses to S. neurona in Brazil. Here we used IFAT to search for IgG antibodies against Sarcocystis falcatula-like (Dal-CG23) and S. neurona (SN138) in sera from 342 horses sampled in Campo Grande, Mato Grosso do Sul state (Midwestern), and São Paulo, São Paulo state (Southeastern), Brazil. The 1:25 cutoff value was chosen to maximize sensitivity of the test. IgG antibodies against S. neurona were detected in 239 horses (69.88%), whereas IgG antibodies against S. falcatula-like were detected in 177 horses (51.75%). Sera from 132 horses (38.59%) reacted against both isolates. Absence of reactivity was evidenced in 58/342 horses (16.95%). The lower cutoff used, and the presence of opossums infected with S. falcatula-like and Sarcocystis spp. in the regions where the horses were sampled, might justify the high seroprevalence observed here. Owing to the similarity among antigens targeted in immunoassays, reports on S. neurona-seropositive horses in Brazil may also derive from the exposure of horses to other Sarcocystis species. The role of other Sarcocystis species in causing neurological diseases in horses in Brazil remains unclear.

Brazilian Horses from Bahia State Are Highly Infected with Sarcocystis bertrami.

The protozoan Sarcocystis bertrami (syn. Sarcocystis fayeri) infects horses and has dogs as definitive hosts. Herein we aimed to detect S. bertrami in Brazilian horses destined for human consumption and to determine the frequency of infection in the examined animals. Muscle fragments from 51 horses were collected in a slaughterhouse in Bahia State during three different seasons of the year. Samples from six tissues from each animal were prepared for macroscopic and microscopic evaluation, using tissue grinding, squash and histology. Sarcocystis sp. was observed in 100% of the examined horses. Selected samples were processed for transmission electron microscopy (TEM). Species identification was confirmed using a PCR targeted to the mitochondrial cytochrome c oxidase subunit 1 gene (cox1). Histological examination revealed sarcocysts with variable sizes and shapes, and dispersed within the muscle fibers. When observed by TEM, the sarcocyst wall was wavy and covered by an electrodense layer. The villar protrusions were digitiform and bent. To our knowledge, this study is the first morphological and molecular confirmation of S. bertrami in horses in Brazil and South America.

Molecular characterization of Burkholderia mallei strains isolated from horses in Brazil (2014-2017).

Glanders is an infectious zoonosis caused by Burkholderia (B.) mallei that mainly affects equids. The objective of this work was to provide additional knowledge on the diversity of the strains circulating in Brazil. Six Burkholderia mallei isolates obtained during necropsies of glanderous horses between 2014 and 2017 in two different states (Pernambuco and Alagoas) were analyzed by polymerase chain reaction-high-resolution melting (PCR-HRM). While four strains (9902 RSC, BM_campo 1, BM_campo 3 and UFAL2) clustered in the L3B2 branch, which already includes the Brazilian 16-2438_BM#8 strain, two strains (BM_campo 2.1 and BM_campo 2.2) clustered within the L3B3sB3 branch, which mostly includes older isolates, from Europe and the Middle East. Whole genome sequencing of two of these strains (UFAL2 and BM_campo 2.1), belonging to different branches, confirmed the HRM typing results and refined the links between the strains, including the description of the L3B3Sb3Gp1SbGp1 genotype, never reported so far for contemporary strains. These results suggest different glanders introduction events in Brazil, including a potential link with strains of European origin, related to colonization or trade.

First molecular detection of Spiroplasma spp. in ticks from horses in Brazil

The class Mollicutes comprises microorganisms that lack a cell wall, highly dependent on their host to survive. Within Mollicutes, the genus Spiroplasma comprises motile helical microorganisms associated with various insects and other arthropods. This study aimed to detect and characterize Mollicutes microorganisms in ticks of different species of veterinary importance, using molecular techniques. These ticks were collected from dogs, cats, cattle, and horses from Rio de Janeiro's metropolitan regions. They were morphologically classified and pooled according to their species for subsequent DNA extraction. These samples were tested by PCR using class Mollicutes-specific primers (16S rRNA) and positive amplicons were sequenced. The obtained DNA sequences were compared with other Mollicutes sequences deposited in GenBank. We found that four out of 745 (0.54%) of the tick pools were positive for members of the class Mollicutes, identified as Spiroplasma spp.; of the positive pools, one comprised Amblyomma sculptum adults and three comprised Dermacentor nitens nymphs. The present study describes Spiroplasma spp. in ticks in Brazil for the first time. Nevertheless, due to few reports on these microorganisms, further studies on epidemiology, virulence, and pathogenicity are needed.

Geographical and temporal spread of equine rabies in Brazil

In Brazil, the horse is frequently used in cultural activities, sports, and in rural and urban work, implementing the economy in different social classes. Among the diseases in horses with zoonotic potential, rabies has been neglected in the country, increasing the risk of spreading the disease across borders. The present study evaluated the spatiotemporal distribution and temporal trend of rabies in horses in Brazil between 2010 and 2019. During this period, 1290 cases of rabies were detected in horses in Brazil, mainly in the states of São Paulo (21.7%) and Mato Grosso (13.3%). However, Espírito Santo stood out, with an incidence risk (IR) of 139.7 cases of rabies per 100,000 horses. The years 2013 and 2017 had higher peaks of IR for the disease, and the states that contributed to this increase were Mato Grosso, São Paulo, and Espírito Santo. There was no monthly seasonality of the disease among the states. The temporal trend revealed an increase for the northeastern region (Annual Percentage Change [APC]: 8.9%) and for Alagoas State (APC: 26.6%). In the spatiotemporal analysis, three high-risk clusters were formed: (i) cluster A (Relative Risk [RRs]: 6.21), involving only Minas Gerais, between 2017 and 2019; (ii) cluster B (RRs: 6.18), involving only Mato Grosso, between 2011 and 2013; and (iii) cluster C (RRs:4.71), involving the states of Rio de Janeiro and Espírito Santo, between 2010 and 2014. Only the states of Roraima and Amapá had no cases of equine rabies during the study period. Therefore, rabies in horses occurs in all Brazilian regions, with areas at high risk of infection concentrated in the Southeast. However, attention should be directed to the north-eastern and northern states, where notifications were infrequent, with an unknown risk in relation to the spread of rabies to transboundary regions. This is the first study evaluating the interstate distribution of rabies in equine species in regions of Brazil.

Myonecrosis caused by Clostridium septicum in a horse from Southern Brazil

Clostridial myonecrosis is a highly fatal infectious disease of the muscle that is caused by pathogenic clostridia. When it occurs in equine muscle, the infection can cause a variety of clinical signs. The present report described a case of acute myonecrosis caused by Clostridium septicum in a horse, which had a favorable clinical evolution. A 6-year-old mare was admitted to a veterinary hospital due to increased volume and lameness in the left pelvic limb after an intramuscular injection of an anti-inflammatory drug. The diagnosis of myonecrosis caused by C. septicum was based on clinical and laboratory findings. The animal showed significant improvement after 5 months of treatment and was discharged from the hospital. There is very limited information regarding myonecrosis caused by C. septicum in horses in Brazil; our study showed that early diagnosis and prompt appropriate treatment can ensure significant improvement and recovery of affected animals.

Preliminary study on tick ectoparasites of horses: effects on tick development and on the haematological parameters of hosts

ABSTRACT Amblyomma sculptum and Dermacentor nitens are the most common tick species that affect horses in Brazil. They induce immunological responses, which reflect the intensity of tick infestation and their life cycle. This study compares the development of these ticks feeding on two horse breeds, and the influence of biological parameters and infestation on haematological values. A total of 12 female horses (6 Mangalarga Marchador and 6 Breton Postier) were subjected to natural tick infestation, counting, and collection. Additionally, blood samples from each animal were collected. Engorged female ticks were kept in a Bio-Oxygen Demand incubator to monitor their development. A significant negative correlation was found between the tick count and the haematological parameters of horses: White Blood Cell, Red Blood Cell, Haemoglobin, and Packed Cell Volume. Our results demonstrate that the animals of two breeds have a similar influence on the development of ticks and that although haematological parameters are correlated with parasitism, the variation in resistance and susceptibility of these animals is probably related to specific characteristics of each animal and not because of the breed.

Prospecting Biomarkers for Diagnostic and Therapeutic Approaches in Pythiosis.

Pythiosis, whose etiological agent is the oomycete Pythium insidiosum, is a life-threatening disease that occurs mainly in tropical and subtropical countries, affecting several animal species. It is frequently found in horses in Brazil and humans in Thailand. The disease is difficult to diagnose because the pathogen’s hyphae are often misdiagnosed as mucoromycete fungi in histological sections. Additionally, there is no specific antigen to use for rapid diagnosis, the availability of which could improve the prognosis in different animal species. In this scenario, we investigated which P. insidiosum antigens are recognized by circulating antibodies in horses and humans with pythiosis from Brazil and Thailand, respectively, using 2D immunoblotting followed by mass spectrometry for the identification of antigens. We identified 23 protein spots, 14 recognized by pooled serum from horses and humans. Seven antigens were commonly recognized by both species, such as the heat-shock cognate 70 KDa protein, the heat-shock 70 KDa protein, glucan 1,3-beta-glucosidase, fructose-bisphosphate aldolase, serine/threonine-protein phosphatase, aconitate hydratase, and 14-3-3 protein epsilon. These results demonstrate that there are common antigens recognized by the immune responses of horses and humans, and these antigens may be studied as biomarkers for improving diagnosis and treatment.

Equine coital exanthema caused by equid alphaherpesvirus 3: a report of an outbreak in northeastern Brazil

ABSTRACT: Equine coital exanthema is a venereal infectious disease poorly reported in horses in Brazil and was never described in the northeastern region of the country. This work aims to describe the clinical and pathological aspects of an outbreak of equine coital exanthema caused by equid alphaherpesvirus 3, occurred in a herd of horses at the semiarid region of the State of Rio Grande do Norte. Main clinical signs consisted of anorexia, hiporexia, fibrinous or purulent secretion in the penis mucosa and vagina. Two mares presented mild to minimal lesions that consisted of scars in the mucosa of the vagina and in the perivulvar region. In a stallion the disease consisted of severe, multifocal, umbilicated-exanthematous ulcers of approximately 1cm in diameter on the penis mucosa. Other areas where ulcers and crusts were focally observed included the skin of the scrotum and on the lips and mucocutaneous junctions of the oral cavity. Histologically, the main lesion consisted of multifocal severe ulcerative and fibrinous necrotizing balanoposthitis and mild multifocal necrotizing, lymphocytic dermatitis in the lips and scrotum. The equide alphaherpesvirus 3 DNA was amplified in blood samples and penis mucosa using the PCR technique. This is the first report of molecular diagnosis of equine coital exanthema affecting horses in northeastern Brazil. Further studies should be carried out in order to investigate the epidemiology and the importance of this herpetic disease in the country.

Erythema Multiforme and its Clinicopathological Features in a Horse in Brazil

Background: Erythema multiforme (EM) is an immune-mediated skin disease which may manifest as cutaneous or mucocutaneous lesions. It is uncommon in horses. EM lesions have a symmetrical bilateral distribution; they are usually urticarial, necrotizing, and, less commonly, ulcerative. In equines, the trigger is usually unknown, and cases are often classified as idiopathic. Diagnosis is based on a thorough history and physical and histopathological examination of lesions. According to the clinical presentation and histopathological characteristics of the cutaneous lesions, this case is the first report to describe diagnosis and treatment of a horse with EM in Brazil. Case: A Quarter Horse filly was followed clinically for 12 months after sudden onset of skin lesions at 18 months of age. The initial lesions were non-alopecic papules with a symmetrical bilateral distribution. Six months after onset, the skin lesions maintained the original distribution pattern; however, they had progressed to papules and plaques with varying annular, arciform, serpiginous, targetoid, or alopecic appearance. At 8 months, the same distribution pattern and appearance remained, but the lesions had become more severe and extensive, with involvement of the labial commissures and perineal region, without any erosions/ulcerations, scaling/crusting, pain, or pruritus. At 12 months, new nodular lesions were found on the medial and lateral surfaces of the hind limbs, neck, bilateral trunk, and root of the tail. The lesions were firm, non-pruritic, and non-tender on palpation. Swabs were obtained from the papular lesions. Skin specimens were also obtained with a 6-mm punch and via incisional biopsy and histological sections were made. Bacterial and fungal cultures were negative. Appropriate stains did not identify fungal structures, were negative for acid-fast bacilli, and did not reveal any metachromatic granules in the sampled cell population. The histopathological findings were characteristic of immune-mediated disease, with a vacuolar interface dermatitis affecting the hair follicles more than the epidermis, necrotic keratinocytes, lymphocyte satellitosis, leukocytoclastic mixed vasculitis of the mid-dermis and deep dermis, and variable granulation tissue, consistent with erythema multiforme and leukocytoclastic vasculitis. Immunosuppressive therapy with corticosteroids and oral supplementation with omega-3 and omega-6 fatty acids and vitamin E were prescribed. After institution of therapy, no new lesions developed, the existing lesions remained stable (though permanent), and hair regrew in the previously alopecic areas. All physiological parameters remained normal throughout the follow-up period. Discussion: Erythema multiforme is rarely reported in horses. According to our literature review, this is the first description of EM in horses in Brazil. EM should be included in the differential diagnosis of horses that present with plaques in a diverse, geographic distribution and a negative initial dermatological screening examination. Further clinical investigation is warranted, with special attention to potential antigenic triggers. A thorough drug and dietary history and close attention to comorbidities are essential, as the suppression of potential culprit factors has important prognostic value and contributes to the elucidation of EM triggers.

Serological and molecular detection of Theileria equi in horses from Sinop, Mato Grosso state, Brazil

Equine piroplasmosis is the most important tick-borne disease to affect horses in Brazil. Theileria equi is one of the causative agents of equine piroplasmosis. Chronic cases are expected, in which the animals show no apparent signs of infection and remain asymptomatic but constitute a source of the infectious agent that ticks can spread. This study was conducted across 81 ranches located in the municipality of Sinop, State of Mato Grosso, Brazil. A sample calculation was performed to estimate the apparent prevalence of T. equi among horses. A total of 1,853 animals were included in the sampling analysis based on the information available from the Institute of Agricultural and Livestock Defense of Mato Grosso State. The serological analysis of 367 serum samples using an indirect enzyme-linked immunosorbent assay (ELISA) to detect anti-T. equi antibodies revealed that 337 animals were positive, representing a frequency of 90.70%. The molecular analysis designed to amplify the EMA-1 gene, which T. equi harbors, showed positivity in 20 of 89 tested samples. The fragments of four samples were sequenced and analyzed to determine their similarities to sequences from other species, based on sequences deposited at GenBank, and all showed 100% similarity with T. equi. Our study represents the first report of T. equi antibodies among the equids in northwestern Mato Grosso, revealing the widespread distribution of seropositive animals.

Occurrence of Gasterophilus spp. in Weanling Foals in Southern Brazil

Background: The occurrence of gastrointestinal myiasis caused by Gasterophilus spp. larvae (Diptera: Oestridae) in adult horses has been widely characterized, however data on natural infestation in young foals have been lacking. This observation may be related to the absence of conclusive diagnosis in these individuals, most likely due to logistical or financial constraints. Gastric ulceration is a problem and a significant cause of morbidity in foals, particularly during the weaning stage; therefore, gasterophilosis should be included in the differential diagnosis. The primary purpose of this study was to determine the prevalence of gasterophilosis in 4- to 6-month-old weanling foals.Material, Methods &amp; Results: Seventy-one healthy weanling foals were enrolled in the study. Physical assessment blood sampling and was completed in all foals before the commencement of the experiment. Gastroscopy examinations were performed under sedation (Detomidine 0.01 - 0.02 mg/kg) with a flexible endoscope inserted through nasogastric via. The lumen of the stomach was examined in order to search for botflies’ larvae. Following gastroscopy, foals were classified into 2 groups based on the presence of Gasterophilus spp. larvae in their stomachs: 1) Infected and 2) Not Infected. Infected foals received a single dose of commercial trichlorfon and albendazole equine oral gel and were stalled for 24 h. The passed feces were thoroughly examined, searching for elimination of larvae. A Total of 64% of the foals (n=45/71) harbored Gasterophilus spp. larvae in the stomach. Mild hyperemia in the gastric mucosa was observed in the attachment sites of the parasites. Physical assessment and hematological parameters’ data were analyzed with Shapiro-Wilk normality test. Comparison between groups for clinical signs, hematological parameters and Gasterophilus spp. infection rates were evaluated using the Kruskal-Wallis test or Student's t-test. Statistical significance was set at P &lt; 0.05. There were no statistically significant variations in physical and hematological parameters between foals that were affected and those that were not infected. The larvae found in the feces were subjected to morphological examination, which confirmed the diagnosis of Gasterophilus intestinalis.Discussion: No systemic clinical indications compatible with Gasterophilus infestation were seen, as described in previous studies of horses infected with the parasite. No botfly eggs were observed in the hair of evaluated foals. During gastroscopy, mild hyperemic lesions in the gastric mucosa were observed in the larvae fixation sites. Although no changes in clinical or hematological parameters were noted, the confirmation of parasite presence is a cause for concern due to horses' tolerance for low infestation levels and poor diagnosis. Additionally, the presence of this myiasis in foals may be a significant stressor during the weaning period and should be included in the differential diagnosis of recurring abdominal pain. Furthermore, infected foals might be a reservoir for the parasite and, contribute to the elimination and spread of the larvae in the environment. Thus, inclusion of young horses in deworming protocols targeted to botfly larvae is needed. This is the first report of Gasterophilus intestinalis myiasis in foals in Brazil. Further research is necessary to fully understand the epidemiology and prevalence of this condition in young horses in Brazil, based on the findings of this study. Keywords: Gasterophilus intestinalis, cavity myiasis, gastroscopy, Oestridae.

Evaluation of buffered Trypanosoma evansi antigen and rapid serum agglutination test (BA/Te) for the detection of anti-T. evansi antibodies in horses in Brazil

Surra is an infectious disease caused by Trypanosoma evansi, which affects a large number of domestic and wild animal species. Infection control is based on rapid diagnosis followed by treatment of sick animals. This study aimed to evaluate a buffered T. evansi antigen and rapid serum agglutination test (BA/Te) for the detection of anti-T. evansi antibodies in serum samples of horses. For this purpose, 445 serum samples from horses were evaluated and the results compared with the diagnosis by CATT/T. evansi. Our data show a sensitivity of 92%, specificity of 91% and a degree of agreement kappa (κ) of 0.82 (95% CI: 0.771–0.877, P < 0.01) between BA/Te and CATT/T. evansi. Antigen specificity was also evaluated against reactive serum for other infectious agents circulating in equine herds. In conclusion, our findings show that BA/Te has the potential to be a practical and quick screening method for the detection of anti-T. evansi antibodies in horses.

Horse Agribusiness in Rio de Janeiro, Brazil: Mangalarga Marchador horse’s breeding systems

This work aims to describe the Mangalarga Marchador horse’s breeding systems in the Rio de Janeiro. The geographic distribution of the farms in the mesoregions of Rio de Janeiro State were defined, and the commercial and social importance the Mangalarga Marchador horse’s business is described in this study. Mangalarga Marchador horse breeders were interviewed through a survey. Sampling of the farms was stratified by the mesoregions. The state of Rio de Janeiro has 1,573 members Horse Breeder Association, with 92,162 registered horses, corresponding to 15.43% of the total of Mangalarga Marchador horses in Brazil. Approximately 95.2% of farms have their own area and more than half ranging between 100 to 500ha. Horse breeding is the main activity on 79.2% of the farms, and the main goal is the sale of horses (39%), followed by sports (32.7%) and leisure (18.6%). The properties have, on average, five registered employees. Most of the owners (90%) are male. The average number of horses at these farms is 100 heads, with an average number of 53 mares, maintained mainly on an extensive production system. About 39.9% of pastures are formed by the Brachiaria spp. grass, and Napier grass, also known as Elephant grass, the most used forage supplement. The average monthly consumption of forage and commercial concentrate feed is 12,866kg and 2,800kg respectively per farm. About 90% of breeders declared that the unskilled labor force is the biggest obstacle to the increase of the horse breeding in the Rio de Janeiro.

Reactivity of Horse Sera to Antigens Derived From Sarcocystis falcatula-Like and Sarcocystis neurona.

Sarcocystis neurona and Sarcocystis falcatula are protozoan parasites endemic to the Americas. The former is the major cause of equine protozoal myeloencephalitis, and the latter is associated with pulmonary sarcocystosis in birds. The opossum Didelphis virginiana is the definitive host of these parasites in North America. Four Didelphis species are found in Brazil, and in most reports in this country, Sarcocystis species shed by opossums have been classified as S. falcatula–like. It is unknown whether reports on S. neurona–seropositive horses in Brazil are also derived from exposure of horses to S. falcatula–like. The aim of this study was to test the sera reactivity of 409 horses in Brazil using antigens derived from a Brazilian strain of S. falcatula–like (Sarco-BA1) and from a North American strain of S. neurona (SN138). Samples were examined by immunofluorescent antibody tests (IFATs) at start dilutions of 1:20, and a selected number of samples was tested by Western blot (WB). Sera from 43/409 (10.5%) horses were reactive to S. falcatula–like and 70 of 409 (17.1%) were reactive to S. neurona antigen; sera from 25 animals (6.1%) were positive for both parasites by IFAT. A poor agreement was observed between the two employed IFATs (κ = 0.364), indicating that horses were exposed to more than one Sarcocystis species. Horse sera evaluated by WB consisted of four sera reactive to S. falcatula–like by IFAT, six sera positive to S. neurona by IFAT, two sera that tested negative to both parasites by IFAT, and a negative control horse serum from New Zealand. Proteins in the range of 16 and 30 kDa were recognized by part of IFAT-positive sera using both antigen preparations. We concluded that Brazilian horses are exposed to distinct Sarcocystis species that generate different serological responses in exposed animals. Antigens in the range of 16 and 30 kDa are probably homologous in the two parasites. Exposure of the tested horses to other Sarcocystis species, such as Sarcocystis lindsayi, Sarcocystis speeri, and Sarcocystis fayeri, or Sarcocystis bertrami cannot be excluded in the current study.