Disease associated with equine coronavirus infection and high case fatality rate.

BACKGROUND: Equine coronavirus (ECoV) is associated with clinical disease in adult horses. Outbreaks are associated with a low case fatality rate and a small number of animals with signs of encephalopathic disease are described. OBJECTIVES: The aim of this study is to describe the epidemiological and clinical features of two outbreaks of ECoV infection that were associated with an high case fatality rate. ANIMALS: 14 miniature horses and 1 miniature donkey testing fecal positive for ECoV from two related disease outbreaks. METHODS: Retrospective study describing the epidemiological findings, clinicopathological findings, and fecal viral load from affected horses. RESULTS: In EcoV positive horses, 27% (4/15) of the animals died or were euthanized. Severe hyperammonemia (677 µmol/L, reference range ≤ 60 µmol/L) was identified in one animal with signs of encephalopathic disease that subsequently died. Fecal viral load (ECoV genome equivalents per gram of feces) was significantly higher in the nonsurvivors compared to animals that survived (P = .02). CONCLUSIONS AND CLINICAL IMPORTANCE: Equine coronavirus had a higher case fatality rate in this group of miniature horses than previously reported in other outbreaks of varying breeds. Hyperammonemia could contribute to signs of encephalopathic disease, and the fecal viral load might be of prognostic value in affected horses.

Colic in competing endurance horses presenting to referral centres: 36 cases.

REASONS FOR PERFORMING STUDY: Colic is a common reason for elimination from equine endurance competitions and has recently been identified as the leading cause of mortality in this group of horses. Hydration and electrolyte derangements are often severe, but are probably related to endurance exercise and not necessarily the episode of colic. Better understanding of the causes of colic and the expected outcome is needed to guide treatment decisions in endurance horses. OBJECTIVES: To describe the history, case details, clinical examination, laboratory, treatment and outcomes for horses presenting to equine referral centres for treatment of colic associated with endurance competition and to identify variables associated with prolonged hospitalisation. METHODS: Thirty-six horses from 2 equine referral centres were included in the analysis. In addition to descriptive statistics, Cox proportional hazards models were used to evaluate factors associated with length of hospitalisation. RESULTS: A diagnosis of open or ileus was made in the majority of horses (56%). Salmonellosis and enteritis (Salmonella negative) were also recognised (16%). Exploratory abdominal surgery was performed in 5 of the horses. Only one of 36 horses did not survive to discharge. Previous eliminations from competition (negative association) and total i.v. fluids within the first 24 h (positive association) of admission were both associated with length of hospitalisation. CONCLUSIONS: Endurance horses with colic typically respond to medical treatment but in some cases hospitalisation may be prolonged. The role of Salmonella infections in endurance horses with colic requires further research. POTENTIAL RELEVANCE: Despite potentially severe clinical and laboratory derangements, equine practitioners should make owners aware that the prognosis for competing endurance horses with colic is good when treated appropriately.

A comparison of hypertonic (7.2%) and isotonic (0.9%) saline for fluid resuscitation in horses: a randomized, double-blinded, clinical trial.

BACKGROUND: Hypertonic saline solution (7.2%) (HSS) can quickly replace intravascular volume deficits. HSS more recently has been advocated in the treatment of traumatic brain injury, but its use in dehydrated patients remains controversial. HYPOTHESIS: Hypertonic saline solution will show a significant improvement in both clinical and laboratory hydration parameters as compared to isotonic (0.9%) saline solution (ISS). ANIMALS: Endurance horses eliminated from the 2009 Western States 100-mile (220-km) endurance ride and requiring IV fluid therapy were eligible for enrollment in the study. METHODS: Twenty-two horses were randomly assigned to receive 4 mL/kg of either HSS or ISS along with 5 L lactated Ringer's solution (LRS). After this bolus, horses were treated with additional LRS in varying amounts. Blood and urine samples were collected before, during, and after treatment. Data were compared using 2-way ANOVA with repeated measures. RESULTS: As compared to ISS, HSS horses showed greater decreases in PCV (P = .04), total protein (P = .01), albumin (P = .01), and globulin (P = .02) concentrations. HSS horses showed greater increases in sodium and chloride (P < .001) as compared to ISS horses. Horses receiving HSS had a shorter time to urination (P = .03) and lower specific gravity (P < .001) than those receiving ISS. CONCLUSIONS: Results of this study indicate that HSS may provide faster restoration of intravascular volume deficits than ISS in endurance horses receiving emergency medical treatment. More marked electrolyte changes should be expected with HSS, however, and additional fluids after HSS administration likely are needed.

Actinomyces species as a cause of abscesses in nine horses.

The characteristics, history, clinical signs, treatment and outcome of nine horses with abscesses caused by Actinomyces species were reviewed. dna sequencing was used to determine the species of one of the isolates. The horses were one to 11 years of age, and the abscesses were most commonly located in the submandibular and retropharyngeal regions. The bacterium was usually cultured as the sole isolate and the horses were most often affected in the autumn. Most of the abscesses were treated with antimicrobials and drainage, but some of them recurred. The horses with submandibular abscesses had residual scar tissue that in some cases did not resolve.

Independent production of CO2 sensitivity by nuclear gene Dly and a transmissible agent from delayed-recovery Drosophila melanogaster.

Flies of stocks designated delayed-recovery by McCrady and Sulerud (1964) remain temporarily paralyzed after exposure to carbon dioxide. This condition is similar to CO2-sensitivity, which occurs in flies infected with the maternally transmitted sigma viruus, but is due, at least in part, to the third chromosome mutant gene Dly. Because earlier work indicated that extracts of delayed-recovery flies could occasionally transmit CO2 sensitivity when injected into resistant recipients, we have tested the possibility that some delayed-recovery stocks contain a sigma-like transmissible virus, in addition to the Dly gene. We found that TDR-orange, a stock derived from the original delayed-recovery line, and temperature-cured populations of the same stock, both contain some agent that is transmissible by injection. TDR-BC3f, a stock derived by backcrossing through the male line to eliminate maternally transmitted factors, does not appear to contain such an infectious agent, but remains sensitive to CO2. These observations lead us to the conclusion that the originally described delayed-recovery stocks harbor an infectious extrachromosomal agent, in addition to possessing the Dly gene, and each is capable of producing a sensitivity to carbon dioxide.