Veterinary Research Forum

Abstract Disorders and injuries of the fetlock joint, encompassing both bone and soft tissue, are significant causes of limb pain and lameness in horses. Over time, these conditions can lead to joint dysfunction and a diminished quality of life. This study aimed to identify fetlock joint disorders using radiological examinations conducted during pre-purchase evaluations of horses and to evaluate the influence of age and sex on their incidence rates. 100 horses were selected from equestrian centers in Tehran Province during 2017 - 2020. As part of pre-purchase examinations, standard radiographic projections of the fetlock joints of all four limbs were obtained. Among the 100 horses examined, 28 showed no abnormalities in the fetlock joint, while 72 exhibited at least one disorder. Osteoarthritis was the most frequently observed condition, with an incidence of 26.75%, followed by soft tissue swelling (15.80%), medial and lateral proximal sesamoiditis (6.00%), osteochondritis dissecans (7.50%) and avulsion fractures (1.50%). Other disorders accounted for less than 5.00% of cases. The prevalence of disorders was significantly higher in the forelimbs compared to the hindlimbs, while no significant difference was found between male and female horses. The findings of this study underscored the importance of conducting pre-purchase radiographic examinations, particularly of the fetlock joints in both forelimbs and hindlimbs. These evaluations are crucial for identifying potential bone complications and for assessing the prognosis of a horse athletic performance.

Abstract The transmission of Escherichia coli (E. coli) containing virulent genes from animals to humans and the environment poses significant public health challenges. This study aimed to detect the virulence factor of the E. coli heme-utilization gene A (chuA) in E. coli isolated from the feces of apparently healthy horses in the island of Sumbawa, Indonesia. The study utilized 52 fecal samples from a total horse population of 283, calculated using the disease detection formula. Fresh feces were collected immediately after excretion and placed in buffered peptone water for subsequent analysis. The samples were then isolated on eosin methylene blue media and identified using biochemical tests. Identified E. coli strains were further examined for detecting the chuA gene using polymerase chain reaction techniques. The E. coli was successfully isolated and identified in 11 (21.15%) of the 52 collected fecal samples. Polymerase chain reaction analysis detected the chuA gene in 8 (15.38%) E. coli isolates at 279 bp on gel electrophoresis. The close interaction between horses and humans in the island of Sumbawa,  Indonesia, may facilitate the spread of E. coli. Thus, surveillance is needed to employ a One Health approach to monitor E. coli strains encoding the chuA gene and other virulence factors to control their dissemination.

Abstract Superficial digital flexor tendon (SDFT) plays an important role in the locomotion of the horses with flexion of the limbs. In the hind limb, it passes over the calcaneal bone and attaches to medial and lateral surfaces of calcaneous by two bands of connective tissue; while, the medial band is weaker than the lateral one. Occasionally, severe trauma, over-extension or fracture of the calcaneous may cause rupture of the supportive bands leading to tendon luxation. An 11-year-old Thoroughbred jumping gelding with symptoms of lameness in both legs, after examination by an internal specialist veterinarian in equine practice field was referred to the Teaching and Research Hospital of the Faculty of Veterinary Medicine of the University of Tehran, Tehran, Iran. Clinical examination showed lateral luxation of SDFT in the right and left tarsal joints. Radiography revealed no sign of calcaneal involvement, except soft tissue swelling. In the radiography of the tarsal joints, the calcaneus bones did not show significant changes, but among the bones of the central and 3^rd tarsal bone (distal intertarsal joint) of the tarsus, osteophyte formation was observed to a mild extent, indicating mild bone spavin in both tarsal joints. In ultrasonography, SDFT thickenings accompanied by hypoechoic regions in tendons were seen, confirming the signs of tendonitis. Moreover, fibrous tissue formation was diagnosed. In the left leg, anechoic fluid in the calcaneous bursa was seen. Evaluation of diagnostic imaging findings enables veterinarians to diagnose the site and extent of the lesions, choosing the appropriate therapeutic approach in addition to clinical symptoms.

Abstract Histoplasma capsulatum is a dimorphic fungus that is traditionally classified in three varieties: Hc var. capsulatum, Hc var. duboisii, and Hc var. farciminosum (HCF). Cytology, hematology, pathology, polymerase chain reaction (PCR), sequencing, and phylogenetic analyses were applied on samples collected from the blood and the eye of a horse with pustular lesions and ocular discharge. Physical examination and cytopathological tests showed H. capsulatum infection. Additionally, the results of two PCR tests confirmed H. capsulatum infection. The phylogenetic tree of the internal transcribed spacer sequence of Iranian H. capsulatum showed homology with the HCF variety. For the first time, H. capsulatum infection in the eye of a horse from Iran was detected and phylogenetically analyzed. This study revealed that H. capsulatum could establish infection in Iranian animals in addition to people, and indicated the role of soil enriched with bird dropping in the preparation of a favorable environment for H. capsulatum propagation. Further investigations are required to clarify the natural history and risk factors associated with histoplasmosis in Iran.

Abstract A 3-year-old Arabian colt was presented for a major gingiva wound at the right rostral part of mandible. After clinical assessments, rostral mandibular fracture was determined. Stabilization of fractured region was achieved via cerclage wire application under general anesthesia. Fixation wires were left in place for 6 weeks. A 3 -month follow up revealed complete fracture healing. The purpose of this case report was to give clinical information about rostral mandibular fractures and treatment of these fractures and nutrition protocol in a horse, as this fracture is of the most common type of jaw fracture sustained by young horses.

Abstract Equine piroplasmosis is a severe disease of horses caused by the intra-erythrocyte protozoan, Theileria equi and Babesia caballi. The aim of this study was to identify equine piroplasmosis based on molecular and morphometrical features in horses in suburb of Urmia, West Azerbaijan province, Iran. From April to September 2011, a total number of 240 blood samples were collected randomly from horses of 25 villages. The specimens were transferred to the laboratory and the blood smears stained with Geimsa, and the morphological and biometrical data of parasite in any infected erythrocyte were considered. Extracted DNA from each blood sample was used in multiplex PCR in order to confirm the presence of B. caballi and T. equi. Microscopic observation on 240 blood smears determined that 15 (6.25%) and 5 (2.80%) samples were infected by T. equi and B. caballi, respectively. The mixed infections occurred in 2 (0.83%) samples. The results of the PCR assays showed 26 (10.83%), 14 (5.83%) and 4 (1.66%) were distinguished as T. equi, B. caballi and mixed infection, respectively. Differences in infection rates were statistically nonsignificant between male and female horses and among different age groups. Our findings indicated that T. equi and B. caballi were prevalent in horse population.