Why do rats get pneumonia? - briefly
Rats develop pneumonia when infectious agents—bacteria, viruses, or fungi—colonize the lungs, especially after stress, weakened immunity, or impaired respiratory clearance. Overcrowded housing, low temperatures, and contaminated bedding heighten the risk of infection.
Why do rats get pneumonia? - in detail
Rats develop lung inflammation when microorganisms invade the lower respiratory tract, when the airways are damaged, or when immune defenses are compromised. The most common bacterial agents are Streptococcus pneumoniae, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Viral contributors include Sendai virus, rodent coronaviruses, and hantavirus. Fungal organisms such as Pneumocystis spp. can cause disease in immunosuppressed individuals.
Pathogenesis begins with colonization of the nasal passages or trachea. Impaired mucociliary clearance—often a result of dust, ammonia, or cold, dry air—allows pathogens to reach the alveoli. Once there, bacterial toxins and viral replication trigger an inflammatory cascade that damages the alveolar epithelium, increases vascular permeability, and fills the air spaces with exudate. The resulting fluid accumulation interferes with gas exchange, producing the clinical signs of coughing, labored breathing, and reduced activity.
Risk factors are largely environmental. Overcrowded cages, poor ventilation, high humidity, and accumulation of waste raise aerosolized pathogen loads. Nutritional deficiencies weaken systemic immunity, while chronic stress from handling or predator cues suppresses cellular defenses. Young and aged rats are particularly vulnerable because their immune systems are either immature or senescent. Genetic strains differ in susceptibility; some inbred lines lack effective IgA responses in the respiratory mucosa.
Diagnostic procedures typically include:
- Observation of respiratory rate, posture, and nasal discharge.
- Radiographic imaging to identify infiltrates or pleural effusion.
- Collection of bronchoalveolar lavage fluid for culture, Gram stain, and PCR identification of specific agents.
- Hematologic analysis to detect leukocytosis or lymphopenia.
Control measures focus on minimizing exposure and supporting immunity:
- Maintain cage density below 2 rats per standard housing unit.
- Provide filtered, fresh air with temperature between 20–22 °C and relative humidity 40–60 %.
- Replace bedding weekly and clean cages to reduce ammonia concentrations.
- Supply a balanced diet enriched with vitamins A, D, and E.
- Implement routine health monitoring to detect early respiratory signs.
- Apply targeted antimicrobial therapy based on culture results; avoid prophylactic broad‑spectrum antibiotics to prevent resistance.
Understanding the interplay of pathogen load, environmental stressors, and host immunity explains the prevalence of pulmonary infection in rodent colonies and guides effective prevention and treatment strategies.