Clostridial Diseases (Botulism and Tetanus).

Botulism and tetanus are the 2 primary manifestations of neurologic disease caused by clostridial toxins. Only a small dose of clostridial toxin is required to induce severe, and often fatal, disease. Consequently, definitive diagnosis of either disease is nearly impossible to achieve antemortem or postmortem; presumptive diagnosis is usually made based on physical and neurologic examination findings. Because the severity of clinical signs can worsen rapidly, prognosis worsens when therapeutic intervention is delayed. Highly effective vaccines are available against both botulism and tetanus and are critical in preventative approaches to control.

Headshaking in 5 horses after paranasal sinus surgery.

OBJECTIVE: To report headshaking and presumptive trigeminal neuritis as a potential complication after paranasal sinus surgery in horses. STUDY DESIGN: Retrospective case series. ANIMALS: Horses (n = 5) that developed headshaking within 45 days of paranasal sinus surgery. METHODS: Medical records (2007-2010) of horses that had been evaluated for headshaking after paranasal sinus surgery were reviewed. RESULTS: Of 5 horses that developed headshaking within 45 days of paranasal sinus surgery, resolution occurred after treatment in 2 horses. One horse was euthanatized because clinical signs associated with headshaking could not be controlled. Headshaking persisted in the other 2 horses but was either adequately controlled with analgesics or was considered infrequent and transient enough to not warrant therapeutic intervention. Only 2 of 5 horses returned to full work after development of headshaking. CONCLUSIONS: Headshaking because of presumptive trigeminal neuritis is a possible career-ending or fatal complication of paranasal sinus surgery in horses.

Dynamics of androgens in healthy and hospitalized newborn foals.

BACKGROUND: Information on steroids derived from the adrenal glands, gonads, or fetoplacental unit is minimal in newborn foals. OBJECTIVE: To measure androgen concentrations in serum and determine their association with disease severity and outcome in hospitalized foals. ANIMALS: Hospitalized (n = 145) and healthy (n = 80) foals. METHODS: Prospective, multicenter, cross-sectional study. Foals of ≤3 days of age from 3 hospitals and horse farms were classified as healthy and hospitalized (septic, sick nonseptic, neonatal maladjustment syndrome [NMS]) based on physical exam, medical history, and laboratory findings. Serum androgen and plasma ACTH concentrations were measured with immunoassays. Data were analyzed by nonparametric methods and univariate analysis. RESULTS: Serum dehydroepiandrosterone (DHEA), androstenedione, testosterone, and dihydrotestosterone (DHT) concentrations were higher upon admission in hospitalized foals (P < .05), were associated with nonsurvival, decreased to 4.9-10.8%, 5.7-31%, and 30.8-62.8% admission values in healthy, SNS, and septic foals, respectively (P < .05), but remained unchanged or increased in nonsurviving foals. ACTH:androgen ratios were higher in septic and NMS foals (P < .05). Foals with decreased androgen clearance were more likely to die (odds ratio > 3; P < .05). CONCLUSIONS AND CLINICAL IMPORTANCE: Similar to glucocorticoids, mineralocorticoids, and progestagens, increased serum concentrations of androgens are associated with disease severity and adverse outcome in hospitalized newborn foals. In healthy foals, androgens decrease over time, however, remain elevated longer in septic and nonsurviving foals. Androgens could play a role in or reflect a response to disorders such as sepsis or NMS in newborn foals.

Identification of a Ruminant Origin Group B Rotavirus Associated with Diarrhea Outbreaks in Foals.

Equine rotavirus group A (ERVA) is one of the most common causes of foal diarrhea. Starting in February 2021, there was an increase in the frequency of severe watery to hemorrhagic diarrhea cases in neonatal foals in Central Kentucky. Diagnostic investigation of fecal samples failed to detect evidence of diarrhea-causing pathogens including ERVA. Based on Illumina-based metagenomic sequencing, we identified a novel equine rotavirus group B (ERVB) in fecal specimens from the affected foals in the absence of any other known enteric pathogens. Interestingly, the protein sequence of all 11 segments had greater than 96% identity with group B rotaviruses previously found in ruminants. Furthermore, phylogenetic analysis demonstrated clustering of the ERVB with group B rotaviruses of caprine and bovine strains from the USA. Subsequent analysis of 33 foal diarrheic samples by RT-qPCR identified 23 rotavirus B-positive cases (69.69%). These observations suggest that the ERVB originated from ruminants and was associated with outbreaks of neonatal foal diarrhea in the 2021 foaling season in Kentucky. Emergence of the ruminant-like group B rotavirus in foals clearly warrants further investigation due to the significant impact of the disease in neonatal foals and its economic impact on the equine industry.