Difference Between Actinomycosis and Actinobacillosis


Actinomycosis and actinobacillosis are two distinct infectious diseases that affect both humans and animals. While they share similarities in their names and symptoms, they are caused by different bacteria and have distinct clinical presentations. In this article, we will explore the difference between actinomycosis and actinobacillosis, their causes, symptoms, and treatment options.

Actinomycosis: Definition and Causes

Actinomycosis is a chronic bacterial infection caused by Actinomyces species, primarily Actinomyces israelii. This bacterium is commonly found in the oral cavity, gastrointestinal tract, and female genital tract of humans. It can also be present in the soil and animal feces.

Causes of Actinomycosis

  • 1. Bacteria: Actinomyces israelii is the primary causative agent of actinomycosis in humans. It enters the body through wounds, dental procedures, or aspiration of contaminated material.
  • 2. Predisposing Factors: Certain factors, such as poor oral hygiene, dental caries, trauma, immunodeficiency, and presence of foreign bodies, increase the risk of actinomycosis.

Actinobacillosis: Definition and Causes

Actinobacillosis is an infectious disease caused by Actinobacillus species, particularly Actinobacillus lignieresii. This bacterium is commonly present in the oral cavity and upper respiratory tract of animals, such as cattle, sheep, and pigs.

Causes of Actinobacillosis

  • 1. Bacteria: Actinobacillus lignieresii is the primary causative agent of actinobacillosis in animals. It enters the body through mucosal surfaces or wounds.
  • 2. Transmission: Direct contact with infected animals, ingestion of contaminated feed or water, and inhalation of aerosolized bacteria can lead to the transmission of actinobacillosis.

Clinical Presentation and Symptoms

While actinomycosis and actinobacillosis are both bacterial infections, they present with different clinical manifestations and symptoms.

Actinomycosis Symptoms

  • 1. Oral and Cervicofacial Actinomycosis: This is the most common form of actinomycosis in humans. It usually presents as a slowly growing, painless swelling or abscess in the jaw or neck region. It can cause sinus tracts, draining fistulas, and inflammation of the surrounding tissues.
  • 2. Thoracic Actinomycosis: Thoracic actinomycosis can manifest as a lung infection, leading to symptoms such as cough, chest pain, and shortness of breath. It can also cause the formation of lung abscesses or pleural effusion.
  • 3. Abdominal and Pelvic Actinomycosis: Infection in the abdomen or pelvis can cause symptoms such as abdominal pain, fever, weight loss, and the formation of abscesses or masses.

Actinobacillosis Symptoms

  • 1. Cutaneous Actinobacillosis: This form of actinobacillosis usually presents as localized skin lesions or abscesses in animals. The lesions are often painful, swollen, and may have a characteristic “wooden” consistency.
  • 2. Respiratory Actinobacillosis: Infection in the respiratory tract can lead to symptoms such as cough, nasal discharge, difficulty breathing, and pneumonia in animals.
  • 3. Systemic Actinobacillosis: In severe cases, actinobacillosis can spread to other organs, leading to systemic symptoms such as fever, weight loss, and lethargy.

Diagnosis and Treatment

Diagnosis of Actinomycosis and Actinobacillosis

  • 1. Clinical Evaluation: A thorough physical examination and medical history are important in diagnosing both actinomycosis and actinobacillosis.
  • 2. Laboratory Tests: Laboratory tests, such as culturing samples from the affected area, can help identify the causative bacteria. Imaging studies, such as X-rays or CT scans, may be performed to assess the extent of the infection.

Treatment of Actinomycosis and Actinobacillosis

  • 1. Actinomycosis: Treatment of actinomycosis involves a prolonged course of antibiotics, typically penicillin or other beta-lactam antibiotics. Surgical drainage or excision of abscesses may be necessary in some cases.
  • 2. Actinobacillosis: Treatment of actinobacillosis in animals involves the use of antibiotics such as penicillin or tetracycline. In severe cases, surgical intervention may be required to remove abscesses or affected tissues.


**1. Can actinomycosis or actinobacillos## FAQs 1. Can actinomycosis or actinobacillosis be transmitted from animals to humans? Yes, both actinomycosis and actinobacillosis can be transmitted from animals to humans. Direct contact with infected animals, such as through bites or scratches, can lead to transmission. It is important to practice good hygiene and take necessary precautions when dealing with animals known to carry these bacteria. 2. Are there any preventive measures to avoid actinomycosis and actinobacillosis? Prevention of actinomycosis and actinobacillosis involves maintaining good hygiene practices, especially when dealing with wounds or oral health. Proper oral hygiene, regular dental check-ups, and prompt treatment of any infections or injuries can help reduce the risk of actinomycosis. Similarly, in animals, ensuring clean living conditions, proper vaccination, and regular veterinary care can help prevent actinobacillosis. 3. Can actinomycosis or actinobacillosis be fatal? While actinomycosis and actinobacillosis can be severe and debilitating if left untreated, they are generally not fatal. However, in rare cases, if the infection spreads to vital organs or causes complications, it can lead to life-threatening situations. Prompt diagnosis and appropriate treatment are crucial for a successful recovery. 4. Are there any long-term complications associated with actinomycosis and actinobacillosis? In some cases, actinomycosis and actinobacillosis can lead to long-term complications. For example, in actinomycosis, the infection can spread to nearby tissues and cause damage or scarring. In actinobacillosis, chronic respiratory infections or systemic spread can result in chronic respiratory issues or organ damage. Timely and appropriate treatment can help minimize the risk of complications. 5. Can actinomycosis and actinobacillosis be completely cured? Yes, with proper treatment, actinomycosis and actinobacillosis can be cured. The duration of treatment may vary depending on the severity of the infection and the response to antibiotics. It is important to complete the full course of antibiotics as prescribed by the healthcare provider or veterinarian to ensure complete eradication of the bacteria.


In conclusion, while actinomycosis and actinobacillosis share similarities in their names and symptoms, they are distinct infectious diseases caused by different bacteria. Actinomycosis primarily affects humans and is caused by Actinomyces species, while actinobacillosis predominantly affects animals and is caused by Actinobacillus species. Understanding the differences between these two conditions is crucial for accurate diagnosis and appropriate treatment. If you suspect you or your animal may be affected by either of these infections, it is important to seek medical or veterinary attention promptly for proper management and care. Stay vigilant, practice good hygiene, and prioritize your health and the well-being of your animals.

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