Actinobacillosis in Animals

Actinobacillosis is a bacterial disease caused by different Actinobacillus species. These bacteria normally live in the mouth, respiratory tract, or reproductive tract of animals, but they cause disease when they enter the body through wounds or damaged tissues.

It affects many animals including cattle, sheep, goats, pigs, horses, dogs, and rarely chickens.

Causes (Etiology)

The disease is caused by gram-negative bacteria of the genus Actinobacillus.

Important species include:

• Actinobacillus pleuropneumoniae → severe lung disease in pigs
• Actinobacillus suis → septicemia and pneumonia in pigs and foals
• Actinobacillus equuli → infection in foals and horses
• Actinobacillus lignieresii → “Wooden Tongue” in cattle and sheep
• Actinobacillus seminis → infertility and orchitis in rams

Clinical Signs

1. In Pigs

Caused by: A. pleuropneumoniae

Signs:

• High fever
• Severe breathing difficulty
• Coughing
• Sudden death Pneumonia
• Poor growth
• Lung abscesses

Young pigs under 5 months are mostly affected.

2. In Horses and Foals

Caused by: A. equuli

Signs in foals:

• Diarrhea
• Pneumonia
• Joint infection
• Kidney infection
• Septicemia
• Weak sleepy foal (sleepy foal disease)

Signs in adult horses:

• Fever
• Colic
• Peritonitis
• Endocarditis
• Abortion

3. In Cattle and Sheep

Caused by: A. lignieresii

This disease is called Wooden Tongue.

Signs:

• Hard swollen tongue
• Excessive salivation
• Difficulty eating
• Painful tongue
• Tongue protruding from mouth
• Swelling under jaw
• Abscesses in mouth or neck

The tongue becomes hard like wood.

4. In Rams and Sheep

Caused by: A. seminis

Signs:

• Epididymitis
• Orchitis
• Infertility
• Arthritis
• Abortion in ewes

Diagnosis

Diagnosis can be confirmed by:

• Bacterial culture
• PCR test
• ELISA
• Biopsy of lesions

In wooden tongue cases, pus may contain yellow sulfur-like granules.

Treatment

In Pigs and Horses

Treatment includes antibiotics such as:

• Penicillin
• Tetracycline
• Gentamicin
• Ceftiofur
• Cephalosporins
• Florfenicol

Supportive therapy is also important.

In Cattle and Sheep (Wooden Tongue)

Main treatment:

• 70mg/kg (IV Sodium Iodide)
• Sodium iodide IV is the treatment of choice
• Usually repeated after 7–10 days
• Improvement often appears within 48 hours

Severe cases may also need:

• Antibiotics
• Surgical removal of masses
• Cryotherapy

Prevention

In Pigs

• Good ventilation
• Avoid overcrowding
• Quarantine new animal
• Vaccination
• Control other diseases

In Ruminants

• Avoid coarse and sharp feed
• Avoid thorny pasture plants
• Prevent mouth injuries

In Rams

• Regular testing
• Remove carrier animals
• Separate young and adult rams

Key Points

• Actinobacillosis is an important bacterial disease in animals.
• Different species affect different animals.
• Wooden tongue is the most common form in cattle.
• Pigs mainly develop severe pneumonia.
• Foals may develop septicemia and joint infection.
• Sodium iodide is the best treatment for ruminants.
• Early diagnosis and treatment improve recovery.

Reference

This content has been prepared after carefully reviewing the clinical experience and research work of Dr. Grace VanHoy (DVM, MS, DACVIM-LA), Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, and Dr. Angel Abuelo (DVM, PhD, DABVP, DECBHM, FHEA, MRCVS), Michigan State University College of Veterinary Medicine, as published on MSD Veterinary Manual. As a veterinary doctor, I have studied and summarized their expert-reviewed information for educational and clinical awareness purposes.