Why does a rat sneeze and cough? - briefly
Sneezing and coughing in rats signal irritation or inflammation of the upper respiratory tract, frequently triggered by dust, strong odors, viral or bacterial infections, or allergic reactions. Persistent symptoms warrant veterinary assessment to diagnose conditions such as Mycoplasma pulmonis or respiratory parasites.
Why does a rat sneeze and cough? - in detail
Rats exhibit sneezing and coughing as reflexes triggered by irritation of the upper and lower respiratory tract. Irritants such as dust, strong odors, aerosolized chemicals, or sudden temperature changes stimulate sensory receptors in the nasal mucosa and tracheobronchial tree. Activation of trigeminal afferents generates a rapid, coordinated contraction of the inspiratory muscles, forcing air out of the nasal passages and producing a sneeze. Stimulation of vagal afferents in the bronchial epithelium initiates a cough, which involves a deep inhalation followed by closure of the glottis, increased intrathoracic pressure, and abrupt expulsion of air to clear the airway.
Pathogenic agents frequently induce these reflexes. Bacterial infections (e.g., Pasteurella multocida, Streptococcus pneumoniae) and viral agents (e.g., Sendai virus, rat coronavirus) cause inflammation of the respiratory mucosa, leading to edema, mucus hypersecretion, and heightened sensitivity of cough receptors. Mycoplasma pulmonis, a common chronic respiratory pathogen in laboratory rats, produces persistent nasal discharge and frequent sneezing due to ongoing epithelial irritation. Fungal spores and parasitic infestations (e.g., Syphacia ruficollis) may also provoke similar responses.
Allergic reactions represent a non‑infectious cause. Exposure to allergens such as pollen, mold, or proteinaceous feed components activates IgE‑mediated pathways, releasing histamine and leukotrienes. These mediators increase vascular permeability and stimulate sensory nerves, resulting in episodic sneezing and cough.
Environmental conditions influence the frequency of these reflexes. Poor ventilation raises airborne particulate concentration, while high humidity can promote bacterial growth, both enhancing respiratory irritation. Overcrowding and stress elevate corticosterone levels, suppressing immune function and predisposing rats to respiratory infections that manifest as sneezing and coughing.
Typical clinical assessment includes:
- Observation of frequency and pattern of sneezes and coughs.
- Nasal and oropharyngeal swabs for microbiological culture.
- Radiographic imaging to detect pulmonary infiltrates.
- Histopathological examination of nasal turbinates and lung tissue for inflammatory changes.
Management strategies focus on eliminating irritants, improving cage hygiene, and providing appropriate antimicrobial or anti‑inflammatory therapy based on diagnostic results. Preventive measures such as HEPA filtration, regular health monitoring, and quarantine of new arrivals reduce the incidence of respiratory reflexes in rat colonies.