Variations in equid SLC11A1 (NRAMP1) genes and associations with Rhodococcus equi pneumonia in horses

Rhodococcus equi is an important intracellular pathogen of horses, most commonly causing chronic, suppurative bronchopneumonia in foals. Although most foals likely are exposed to environmental R. equi within the 1st few days of life, only some develop R. equi pneumonia, and the basis of differences in susceptibility among foals currently is unknown. In this study, we investigated solute carrier family 11 member 1 (SLC11A1) gene sequences in the 5' untranslated region, exon 1, and a portion of intron 1 for variations in 3 equid species (horse, donkey, zebra) and compared variants within 3 independent horse breeding farms for associations with R. equi pneumonia by use of an age-matched case-control design. Seven novel variants in the 5'untranslated region were identified as specific for one or both of the non-horse equid species sampled. In addition, a single novel horse variant in the 5'untranslated region, -57C/T, was identified in 4 breeds. The -57C/T variant was found on 2 of the 3 farms with endemic R. equi pneumonia, representing 2 different horse breeds. Significant allelic and genotypic associations with susceptibility to R. equi pneumonia were observed for the -57C/T variant in foals from these farms. Although the functional impact of this novel variant remains to be determined, this study represents an important step in our understanding of natural resistance to R. equi foal pneumonia and other intracellular bacterial diseases affecting equids.     

Antibody response to Mycoplasma capricolum subsp. capripneumoniae bacterium in small holder dairy goats in Tanzania

Contagious caprine pleuropneumonia (CCPP), an Office International des Epizooties listed disease, can cause significant levels of morbidity and mortality in goats in Africa, the Middle East, and Western Asia. A cross-sectional study was conducted to determine the seroprevalence of CCPP, in two contrasting administrative districts of northern Tanzania, namely, Babati and Arumeru. A total of 337 serum samples were collected from January to July 2010, from apparently clinically healthy unvaccinated dairy goats breeds of different ages and sexes. Samples were subjected to monoclonal antibody-based competitive enzyme-linked immunosorbent assay for the specific measurement of antibodies to Mycoplasma capricolum subsp. capripneumoniae bacterium. The overall animal flock and village-level seroprevalence of CCPP was found to be 3.3 % [95 % confidence interval (CI)?=?1.6–5.8], 9.6 % (95 % CI?=?4.7–16.9), and 31.5 % (95 % CI?=?15.6–56.5), respectively. There was no evidence (p?=?0.659) of differences in seroprevalence between samples from the two administrative locations. Despite the fact that there was no significant difference (p?>?0.05) in seropositivity between sex and age and between breeds sampled, there was a significant difference (p?<?0.05) in seropositivity between the different physiological status groups examined with the non-lactating (dry) category of goats showing a higher seroprevalence. The findings of this survey revealed evidence of dairy goat exposure to M. capricolum subsp. capripneumoniae, although at a low prevalence. It is therefore advisable to include CCPP serology in the seromonitoring program so as to give a better indication of flock immunity. This should lead to the establishment of appropriate CCPP control measures in smallholder dairy goat flocks, which are increasingly being recognized for their value as a vital source of livelihood for resource poor livestock keepers in Tanzania.     

A mitochondrial pyruvate carrier required for pyruvate uptake in yeast, Drosophila, and humans

Pyruvate constitutes a critical branch point in cellular carbon metabolism. We have identified two proteins, Mpc1 and Mpc2, as essential for mitochondrial pyruvate transport in yeast, Drosophila, and humans. Mpc1 and Mpc2 associate to form an ~150-kilodalton complex in the inner mitochondrial membrane. Yeast and Drosophila mutants lacking MPC1 display impaired pyruvate metabolism, with an accumulation of upstream metabolites and a depletion of tricarboxylic acid cycle intermediates. Loss of yeast Mpc1 results in defective mitochondrial pyruvate uptake, and silencing of MPC1 or MPC2 in mammalian cells impairs pyruvate oxidation. A point mutation in MPC1 provides resistance to a known inhibitor of the mitochondrial pyruvate carrier. Human genetic studies of three families with children suffering from lactic acidosis and hyperpyruvatemia revealed a causal locus that mapped to MPC1, changing single amino acids that are conserved throughout eukaryotes. These data demonstrate that Mpc1 and Mpc2 form an essential part of the mitochondrial pyruvate carrier.     

Evaluation of risk factors associated with development of postoperative ileus in horses

OBJECTIVE: To determine factors associated with development of postoperative ileus (POI) in horses undergoing surgery for colic. DESIGN: Prospective case-control study. ANIMALS: 251 horses undergoing colic surgery, of which 47 developed POI. PROCEDURE: Signalment, history, clinicopathologic data, pre- and postoperative treatments, lesions, complications, costs, and outcome were recorded for all horses during hospitalization. RESULTS: Variables associated with increased odds of POI included small intestinal lesion, high PCV, and increased duration of anesthesia. There was modest evidence that pelvic flexure enterotomy and intraoperative administration of lidocaine may have reduced the odds of developing POI. CONCLUSIONS AND CLINICAL RELEVANCE: Findings during the preoperative and intraoperative periods can be used to identify horses at increased risk of POI. Reducing surgical and anesthetic duration should decrease the incidence of POI.     

Evaluation of urine sucrose concentration for detection of gastric ulcers in horses

OBJECTIVE: To evaluate the use of sucrose permeability testing to detect ulcers in the gastric squamous mucosa of horses. ANIMALS: 13 adult horses ranging from 5 to 19 years of age. PROCEDURE: Following induction of gastric ulcers by intermittent feed deprivation, horses underwent sucrose permeability testing (administration of sucrose by nasogastric intubation followed by collection of urine at 2 and 4 hours after intubation) and gastric endoscopy. Squamous ulcers were assigned a severity score (range, 0 to 3) by use of an established scoring system. Horses were subsequently administered omeprazole for 21 days, and sucrose testing and endoscopy were repeated. Pair-wise comparisons of urine sucrose concentration were made between horses with induced ulcers before and after omeprazole treatment. Urine sucrose concentrations also were compared on the basis of ulcer severity score. RESULTS: Urine sucrose concentrations and ulcer severity scores were significantly higher in horses with induced ulcers before omeprazole treatment than after treatment. Urine sucrose concentrations were significantly higher for horses with ulcer severity scores > 1. Use of a cut-point value of 0.7 mg/mL revealed that the apparent sensitivity and specificity of sucrose permeability testing to detect ulcers with severity scores > 1 was 83% and 90%, respectively. Results were similar after adjusting sucrose concentrations for urine osmolality. CONCLUSIONS AND CLINICAL RELEVANCE: Urine sucrose concentration appears to be a reliable but imperfect indicator of gastric squamous ulcers in horses. Sucrose permeability testing may provide a simple, noninvasive test to detect and monitor gastric ulcers in horses.     

Evaluation of equine breeding farm management and preventative health practices as risk factors for development of Rhodococcus equi pneumonia in foals

OBJECTIVE: To determine whether foal management practices, environmental management, and preventative health practices are risk factors for development of Rhodococcus equi pneumonia in foals. DESIGN: Prospective matched case-control study. ANIMALS: 2,764 foals on 64 equine breeding farms with 9,991 horses. PROCEDURE: During 1997, participating veterinarians completed paired data collection forms for comparison; 1 for an affected farm (containing > or = 1 foal with pneumonia caused by R equi) and 1 for a control farm. Information collected pertained to stabling facilities, environmental management, foal husbandry, and preventative equine health practices. RESULTS: Matched farm data compared by use of conditional logistic regression indicated that personnel on affected farms were more likely to attend foal births, test foals for adequacy of passive immunity, administer plasma or other treatments to foals to supplement serum immunoglobulin concentrations, administer hyperimmune plasma prophylactically to foals, vaccinate mares and foals against Streptococcus equi infection, and use multiple anthelmintics in deworming programs. Affected farms were also more likely to have foals that developed other respiratory tract disorders and were approximately 4 times as likely to have dirt floors in stalls used for housing foals as were control farms. CONCLUSIONS AND CLINICAL RELEVANCE: Rhodococcus equi pneumonia does not appear to be associated with poor farm management or a lack of attention to preventative health practices. Housing foals in stalls with dirt floors may increase the risk for development of R equi pneumonia.     

Case-control study of early-term abortions (early fetal losses) associated with mare reproductive loss syndrome in central Kentucky

OBJECTIVE: To identify factors associated with abortions during early gestation classified as mare reproductive loss syndrome (MRLS). DESIGN: Case-control study. ANIMALS: 324 broodmares from 43 farms in central Kentucky, including 121 mares from 25 farms that had early-term abortions (ETAs) associated with MRLS (case horses), 120 mares from the same farms but that did not abort, and 83 mares from 18 farms that were not severely Impacted by MRLS. PROCEDURE: Farm managers were interviewed to obtain data on various management practices and environmental exposures for the mares. Data for case and control horses were compared to identify risk factors for mares having MRLS-associated ETAs. RESULTS: Several factors increased the risk of MRLS-associated ETAs, including feeding hay in pasture, greater than usual amounts of white clover in pastures, more eastern tent caterpillars in pastures, abortion during a previous pregnancy, and sighting deer or elk on the premises. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis indicates that certain characteristics of pastures predisposed mares to MRLS-associated ETAs. Methods for limiting exposure to pasture (keeping mares in stalls longer) during environmental conditions similar to those of 2001 (ie, sudden freezing in mid-April following warmer-than-usual springtime temperatures and larger-than-usual numbers of eastern tent caterpillars in and around pastures) should reduce the risk of mares having MRLS-associated ETAs. It was not possible to determine whether exposure to white clover or caterpillars were causal factors for MRLS or were merely indicators of unusual environmental conditions that resulted in exposure of mares to a toxic or infectious agent.     

Comparison of serum and urinary concentrations of clenbuterol with and without concomitant administration of furosemide in horses

Furosemide is frequently used to control or prevent exercise-induced pulmonary hemorrhage in performance horses. The bronchodilating agent clenbuterol is also commonly used as a treatment for inflammatory airway disease in performance horses. Use of both medications is regulated by many racing authorities. The effects of concomitant administration of furosemide and clenbuterol on the pharmacokinetics of clenbuterol have not been well characterized. A study was designed to evaluate the influence of furosemide on serum and urine concentrations of clenbuterol after oral administration of clenbuterol and intravenous administration of furosemide in horses. Results indicated that urinary concentrations of clenbuterol in horses treated concomitantly with furosemide and clenbuterol were increased, whereas serum concentrations of the drug were decreased. These effects persisted during the study period and varied among horses.