Pasteurella multocida is a bacterium frequently found in the upper respiratory tract and oral cavity of rabbits, often without causing obvious illness. This organism is considered zoonotic, meaning it can be transmitted from animals to humans, making it a potential public health concern for rabbit owners and handlers. While exposure is common, clinical infection in humans is infrequent, typically occurring when the bacteria is introduced through a break in the skin. The severity of human infection depends on the route of transmission and the person’s underlying health status.
The Zoonotic Potential of Pasteurella multocida
Pasteurella multocida is a small, Gram-negative bacterium that colonizes the nasopharynx of many mammals, including rabbits. In rabbits, this bacterium is the primary cause of “snuffles,” a respiratory disease characterized by sneezing and nasal discharge, but many animals are asymptomatic carriers. An estimated 30% to 90% of healthy adult domestic rabbits may harbor the organism in their respiratory passages.
The bacterium is classified as zoonotic because it can transmit from the animal host to a human host. Different strains of P. multocida exist, categorized into serotypes; capsular type A is the one most often detected in human infections acquired from rabbits. The presence of the bacteria in a rabbit means a risk of transmission exists, especially since recovered animals often become permanent carriers.
While human exposure is common through close contact with rabbits, the development of a clinical infection is not. Infection usually requires a specific event, like a bite, to introduce the organism past the skin’s protective barrier. People who are immunocompromised or have chronic respiratory conditions are susceptible to developing more serious, systemic infections.
Transmission Routes and Human Manifestations
The most direct and common route for P. multocida transmission from a rabbit to a human is through a traumatic wound, such as a bite or a scratch. The bacteria, which resides in the rabbit’s mouth and respiratory tract, is directly inoculated into the human tissue during the injury. Transmission can also occur if a rabbit licks an open cut or through contact with the animal’s nasal secretions.
A different transmission pathway is the inhalation of aerosolized particles containing the microorganism, especially from a rabbit with severe respiratory pasteurellosis. This airborne route can lead to respiratory infections in humans, though it is less frequent than wound infections. People with chronic lung conditions, such as emphysema, may be more vulnerable to acquiring pneumonia or tracheobronchitis.
In a healthy person, infection typically manifests as a localized soft tissue infection, often developing rapidly within 24 hours of the injury. Symptoms at the wound site include intense swelling, redness (erythema), and tenderness, which can quickly progress to cellulitis, a diffuse skin infection. The rapid onset is a hallmark of P. multocida infections.
In rare cases, especially in individuals with compromised immune systems, the infection can spread beyond the localized site. Systemic complications can include septic arthritis, osteomyelitis (bone infection), or severe conditions like meningitis or endocarditis (heart valve infection). Any deep bite or scratch from a rabbit requires immediate medical evaluation due to the potential for rapid progression and serious complications.
Essential Prevention and Safety Measures
Minimizing the risk of P. multocida transmission begins with consistent personal hygiene after handling rabbits. Hands should be thoroughly washed with soap and water immediately after touching the animal, its enclosure, or contaminated materials. This action removes bacteria transferred through contact with fur, saliva, or nasal secretions.
Owners should employ safe handling techniques to prevent traumatic injuries, which are the primary source of human infection. Avoiding situations that might provoke a rabbit to bite or scratch, and handling the animal gently, significantly reduces the chance of skin penetration. If an open wound or cut is present on a person’s skin, it should be covered with a waterproof bandage before contact with the rabbit.
Managing the rabbit’s health is another element of prevention, as a healthier rabbit poses a lower risk. Any rabbit showing signs of respiratory disease, such as sneezing or nasal discharge, should receive prompt veterinary care to reduce the bacterial load. While antibiotics can control symptoms in rabbits, they are not always effective at eliminating the carrier state, making good husbandry necessary.
If a bite or scratch occurs, immediate and thorough wound care is necessary; the injury should be cleaned with soap and water and disinfected. When infection develops in humans, treatment is effective when initiated quickly, typically involving antibiotics, with penicillin and its derivatives being the preferred choice against localized P. multocida infections. Seeking medical attention immediately after a penetrating injury is the safest course of action.