Calf Coronavirus Enteritis

Calf coronavirus enteritis is a notable cause of neonatal diarrhea in bovines, leading to significant economic losses in the cattle industry. Below is a comprehensive overview tailored for veterinary professionals preparing for the NAVLE examination:

• Type of Agent: Virus

• Classification of the Agent:

  • Family: Coronaviridae

  • Genus: Betacoronavirus

  • Species: Bovine coronavirus (BCoV)(merckvetmanual.com)

• Clinical History:

  • Affects neonatal calves, typically between 5 to 21 days of age

  • High morbidity with variable mortality rates

  • Rapid onset of clinical signs, often within 24–72 hours post-infection

• Transmission of the Disease:

  • Fecal-oral route

  • Respiratory secretions may also play a role in transmission

  • Highly contagious; virus shed in large quantities in feces

  • Environmental stability contributes to rapid spread among neonatal calves

• Causes:

  • Ingestion of BCoV-contaminated feed, water, or fomites(merckvetmanual.com)

  • Exposure to infected animals or asymptomatic carriers

• Clinical Presentation:

  • Acute onset of profuse, watery to pasty diarrhea

  • Feces may contain mucus and, occasionally, blood(merckvetmanual.com)

  • Dehydration(merckvetmanual.com)

  • Depression and weakness

  • Anorexia(merckvetmanual.com)

  • In severe cases, hypovolemic shock and death

• Changes in Clinical Pathology Tests:

  • Hemoconcentration due to dehydration

  • Electrolyte imbalances: hyponatremia, hypokalemia

  • Metabolic acidosis

• Differentials:

  • Enterotoxigenic Escherichia coli infection

  • Cryptosporidiosis

  • Rotavirus enteritis

  • Salmonellosis

  • Coccidiosis

• Diagnostic Tests to Confirm:

  • Antigen-capture ELISA on fecal samples

  • RT-PCR for BCoV RNA detection(merckvetmanual.com)

  • Electron microscopy for viral particle visualization

  • Fluorescent antibody testing on intestinal tissues

• Changes in Other Tests (e.g., Imaging):

  • Typically, imaging is not utilized for diagnosis

• Possible Treatments:

  • Supportive Care:

    • Oral rehydration solutions containing electrolytes and glucose

    • Intravenous fluid therapy in cases of severe dehydration

    • Maintenance of acid-base balance

  • Antimicrobial Therapy:

    • Not indicated for viral infections; however, antibiotics may be administered to prevent or treat secondary bacterial infections

  • Other Medications:

    • Nonsteroidal anti-inflammatory drugs (NSAIDs) for pain and inflammation management

• Zoonotic Risk:

  • Bovine coronaviruses are not considered zoonotic and do not pose a risk to human health

• Reportable Status:

  • Calf coronavirus enteritis is generally not a reportable disease; however, reporting requirements may vary by region

• Disease Control:

  • Prevention:

    • Ensure adequate colostrum intake to confer passive immunity

    • Implement strict biosecurity measures to prevent introduction and spread

    • Maintain proper sanitation and hygiene in calf-rearing areas

    • Vaccination of pregnant dams with coronavirus vaccines to enhance colostral antibodies

  • Management During Outbreaks:

    • Isolate affected animals to reduce transmission

    • Enhance supportive care to affected calves

    • Thoroughly clean and disinfect contaminated environments

• Prognosis:

  • Generally favorable with prompt and appropriate supportive care

  • Delayed or inadequate treatment can lead to increased mortality

Understanding the etiology, transmission, clinical presentation, diagnostic methods, treatment options, and preventive measures is crucial for effective management of calf coronavirus enteritis. This knowledge is essential for veterinary professionals preparing for the NAVLE examination.