How dangerous is mycoplasmosis in rats? - briefly
Mycoplasma infection can cause severe respiratory distress, weight loss, and high mortality rates in laboratory rats, particularly when animals are stressed or immunocompromised. Control requires strict biosecurity measures and appropriate antibiotic therapy.
How dangerous is mycoplasmosis in rats? - in detail
Mycoplasma infections in laboratory rats can produce a spectrum of outcomes, ranging from subclinical colonisation to fatal systemic disease. The severity depends on the species of Mycoplasma, the strain of the host, age, immunological status, and environmental conditions.
Clinical manifestations include respiratory distress (rhonchi, laboured breathing), nasal discharge, conjunctivitis, reduced weight gain, and, in severe cases, septicemia with organ congestion and necrosis. Neonatal and immunocompromised animals display the highest mortality, with reported death rates of 30‑70 % in uncontrolled outbreaks. Adult, immunocompetent rats often survive but may exhibit chronic inflammatory changes in the lungs and upper respiratory tract.
Key factors influencing pathogenicity:
- Mycoplasma species (e.g., Mycoplasma pulmonis is more virulent than M. arthritidis).
- Cohabitation density; high crowding accelerates transmission.
- Stressors such as transport, temperature fluctuations, or concurrent infections.
- Genetic background; certain inbred strains show heightened susceptibility.
Diagnostic procedures rely on:
- Culture on specialized media under aerobic conditions; growth may take 2‑4 weeks.
- Polymerase chain reaction (PCR) targeting conserved 16S rRNA sequences; provides rapid, species‑specific identification.
- Serology (ELISA) for detection of specific antibodies; useful for monitoring herd exposure.
- Histopathology revealing peribronchiolar lymphoid hyperplasia and alveolar infiltrates.
Therapeutic options are limited. Tetracyclines (e.g., doxycycline) and macrolides (e.g., tylosin) reduce bacterial load but rarely eradicate infection completely. Treatment protocols generally combine antimicrobial administration with supportive care (fluid therapy, temperature regulation).
Prevention strategies focus on biosecurity:
- Quarantine new arrivals for at least 4 weeks with PCR screening.
- Maintain low animal density and optimal ventilation.
- Implement routine health monitoring programs that include Mycoplasma testing.
- Use barrier cages and sterilised bedding to minimise environmental contamination.
In research settings, undetected infection can confound experimental data, especially in studies of immunology, respiratory physiology, or pharmacology. Regular surveillance and strict colony management are essential to preserve data integrity and animal welfare.