Top 15 Small Ruminant Diseases for NAVLE: Essential Insights

Top 15 Small Ruminant Diseases: A Comprehensive NAVLE Guide (Part 1)

Introduction

This guide provides detailed information on key diseases affecting small ruminants, offering insights into diagnosis and treatment to help veterinary professionals prepare for the NAVLE. Understanding these conditions is crucial for effective management in sheep and goats.

1. Contagious Ecthyma (Orf)

Classic Case:
Contagious ecthyma, commonly known as orf, affects young or newly introduced animals, presenting with painful papules, vesicles, pustules, and crusts around the lips. Lesions may also appear around erupting teeth, coronary bands, perineum, eyes, and ears, leading to anorexia and lameness.

Diagnosis:

• Etiology: Caused by the parapoxvirus.
• Diagnostic Tools: Clinical history and examination, PCR or electron microscopy for confirmation.

Treatment:

• Course: Typically 1-4 weeks, healing without scars.
• Management: Isolate or cull affected animals, vaccinate others, provide supportive care if not eating.

Pearls:
Orf is zoonotic and highly contagious. Vaccination during an outbreak is effective but should be avoided on orf-free farms due to vaccine-induced disease risk.

2. Clostridial Diseases (Enterotoxemias, Tetanus)

Classic Case:

• Enterotoxemia Type C (Bloody Scours): Affects lambs and kids with bloody diarrhea, seizures, and peracute death.
• Enterotoxemia Type D (Pulpy Kidney Disease): Seen in fast-growing lambs with similar symptoms.
• Tetanus: Presents with stiffness, “sawhorse stance,” and respiratory paralysis.

Diagnosis:

• Etiology: Clostridium perfringens for enterotoxemias, C. tetani for tetanus.
• Diagnostic Tools: Smears, toxin identification via ELISA or PCR.

Treatment:

• Vaccination: Annual “CD&T” vaccination.
• Management: Supportive care and preventive measures for tetanus.

Pearls:
Clostridial bacteria are normal GI flora. Enterotoxemia often results from overeating, while tetanus is caused by neurotoxin production in anaerobic tissue.

3. Gastrointestinal Parasitism

Classic Case:
Symptoms include weight loss, diarrhea, anemia, “bottle jaw,” and poor coat condition. Death may occur in severe cases.

Diagnosis:

• Etiologies: Includes Eimeria spp., Telodorsagia, Trichostrongylus spp., and Haemonchus contortus.
• Diagnostic Tools: Fecal egg count (FEC), FAMACHA score for anemia.

Treatment:

• Targeted Treatment: Based on FEC or FAMACHA score.
• Anthelmintics: Administered via drench, bolus, injection, or feed.

Pearls:
Parasitism transmission is fecal-oral. Strategic deworming and pasture management are crucial for prevention.

4. Caseous Lymphadenitis

Classic Case:
Characterized by peripheral lymph node abscesses, with discharge ranging from creamy to caseous. Internal infections can lead to weight loss and poor condition.

Diagnosis:

• Etiology: Corynebacterium pseudotuberculosis.
• Diagnostic Tools: Culture of abscess material, serology.

Treatment:

• Management: Culling is practical for commercial operations; isolate and treat valuable animals.

Pearls:
Caseous lymphadenitis is zoonotic and highly contagious. Strict biosecurity and vaccination in endemic areas are key prevention strategies.

5. Pneumonia

Classic Case:
Presents with coughing, dyspnea, nasal discharge, and weight loss. Conditions like ovine progressive pneumonia (OPP), maedi-visna (M-V), and ovine pulmonary adenocarcinoma (OPA) have specific presentations.

Diagnosis:

• Etiologies: Include viral (PI-3, adenovirus), bacterial (Mannheimia haemolytica, Pasteurella multocida), and parasitic (Dictyocaulus filaria).
• Diagnostic Tools: Virus isolation, serology, ultrasonography, and necropsy.

Treatment:

• Viral: Supportive care and antibiotics for secondary infections.
• Bacterial: Antibiotics and improved ventilation.
• Parasitic: Anthelmintics and supportive care.

Pearls:
M. haemolytica and P. multocida are normal flora. Parasitic pneumonia often affects lung lobe margins and is rarely clinical.