How does Mycoplasma infection present in rats? - briefly
Mycoplasma infection in rats typically manifests as respiratory symptoms such as sneezing, nasal discharge, and labored breathing, often accompanied by reduced weight gain or weight loss. Additional signs may include ocular discharge, lethargy, and occasional fever.
How does Mycoplasma infection present in rats? - in detail
Mycoplasma infection in laboratory rats produces a spectrum of clinical and subclinical manifestations that vary with species, strain, age, and inoculum dose. Respiratory involvement is most common; affected animals exhibit nasal discharge, sneezing, and labored breathing. In severe cases, interstitial pneumonia develops, characterized histologically by loss of alveolar architecture, edema, and infiltration of mononuclear cells. Weight loss and reduced growth rates frequently accompany chronic infection, reflecting metabolic disruption and decreased feed efficiency.
Gastrointestinal lesions may arise when the organism colonizes the intestinal mucosa. Diarrhea, soft feces, and occasional rectal bleeding indicate mucosal erosion and inflammatory exudate. Histopathology typically shows villous blunting, epithelial cell degeneration, and lymphoid hyperplasia in the lamina propria.
Reproductive performance can decline. Infected females may experience irregular estrous cycles, reduced litter size, and increased neonatal mortality. Testicular atrophy and decreased sperm motility have been documented in males, suggesting direct or indirect effects on gonadal tissue.
Immunological alterations are evident in seropositive rats. Elevated levels of IgM and IgG antibodies against Mycoplasma antigens appear within 7–10 days post‑exposure. Cytokine profiles shift toward a pro‑inflammatory pattern, with increased IL‑1β, TNF‑α, and IFN‑γ in serum and bronchoalveolar lavage fluid.
Diagnostic confirmation relies on a combination of methods:
- Culture: Specialized media (e.g., SP4, Hayflick) under microaerophilic conditions; colonies appear as “fried‑egg” morphology after 2–5 days.
- Polymerase chain reaction (PCR): Species‑specific primers amplify conserved 16S rRNA regions; quantitative assays detect low‑level carriage.
- Serology: Enzyme‑linked immunosorbent assay (ELISA) quantifies antibodies; complement fixation tests provide additional confirmation.
- Histopathology: Tissue sections stained with hematoxylin‑eosin or immunohistochemistry reveal organism‑associated lesions.
Control measures include barrier housing, routine screening of breeding colonies, and antibiotic regimens (e.g., tetracyclines) administered via feed or water. Eradication protocols often combine antimicrobial therapy with depopulation of infected groups and thorough environmental decontamination.