What illnesses affect mice? - briefly
Mice commonly develop viral infections (e.g., mouse hepatitis virus, Sendai virus), bacterial diseases (e.g., Salmonella, Streptococcus), parasitic infestations (e.g., pinworms, mites), fungal infections (e.g., Candida), spontaneous tumors, and metabolic disorders. These ailments can compromise research data and require routine health surveillance.
What illnesses affect mice? - in detail
Mice are susceptible to a wide range of diseases that can be classified by etiology, organ system involvement, and relevance to research or wildlife health.
Bacterial infections commonly observed in laboratory and wild populations include Salmonella enterica, which produces enteritis and septicemia; Pasteurella pneumotropica, associated with respiratory distress and conjunctivitis; Mycoplasma pulmonis, a primary cause of chronic respiratory disease characterized by nasal discharge, dyspnea, and bronchopneumonia; and Streptococcus pneumoniae, leading to pneumonia and meningitis. Diagnosis relies on culture, PCR, or serology, and treatment typically involves appropriate antibiotics guided by susceptibility testing.
Viral pathogens affect mice frequently and often serve as models for human disease. Notable examples are:
- Mouse hepatitis virus (MHV) – a coronavirus causing hepatitis, encephalitis, and enteritis; transmission occurs via fecal‑oral route.
- Lymphocytic choriomeningitis virus (LCMV) – a arenavirus producing meningoencephalitis and persistent infection; spread through bodily fluids.
- Sendai virus – a paramyxovirus inducing acute respiratory syndrome with coughing and lung inflammation.
- Mouse norovirus – a calicivirus linked to subclinical gastrointestinal infection but capable of exacerbating colitis in immunodeficient strains.
Fungal diseases, though less common, include Aspergillus spp. and Candida albicans, which can cause opportunistic pulmonary or systemic mycoses, especially in immunocompromised mice. Diagnosis employs histopathology and culture; antifungal therapy is required for severe cases.
Parasitic infestations involve both internal and external agents:
- Heligmosomoides polygyrus (intestinal nematode) leads to malabsorption, weight loss, and eosinophilia.
- Syphacia obvelata (pinworm) produces perianal irritation and potential secondary bacterial infection.
- Protozoa such as Giardia muris cause diarrheal disease.
- Ectoparasites like Myobia musculi (fur mite) result in pruritus, alopecia, and skin inflammation.
Metabolic and genetic disorders are prominent in laboratory strains. Examples include:
- Obesity and diabetes in leptin‑deficient (ob/ob) or leptin‑receptor‑deficient (db/db) mice, characterized by hyperglycemia, insulin resistance, and fatty liver.
- Atherosclerosis in ApoE‑knockout mice, presenting with lipid deposition in arterial walls.
- Retinal degeneration in rd1 mice, leading to progressive loss of photoreceptors and blindness.
Neoplastic conditions are frequent in aged or genetically engineered mice. Common tumor types:
- Lymphomas (T‑cell or B‑cell) manifesting as enlarged lymph nodes, splenomegaly, and weight loss.
- Mammary adenocarcinomas in hormone‑sensitive strains, presenting as palpable masses.
- Hepatocellular carcinoma in models with activated oncogenes, causing liver enlargement and jaundice.
Respiratory disorders extend beyond infectious agents. Chronic obstructive pulmonary disease can arise from prolonged exposure to irritants, producing airway remodeling and reduced lung capacity. Pulmonary edema may result from heart failure or toxic inhalation.
Gastrointestinal diseases include colitis induced by chemical irritants (e.g., dextran sulfate sodium) or microbial dysbiosis, presenting with bloody diarrhea and weight loss. Megaloblastic anemia due to dietary deficiencies leads to pallor and lethargy.
Neurological conditions encompass:
- Spongiform encephalopathy caused by prion infection (e.g., scrapie), resulting in tremors, ataxia, and fatal neurodegeneration.
- Seizure disorders in certain transgenic lines, with observable convulsions and altered behavior.
- Peripheral neuropathy secondary to vitamin B12 deficiency, causing hindlimb weakness.
Skin disorders are frequently observed:
- Dermatitis from allergic reactions or contact irritants, producing erythema, edema, and pruritus.
- Ulcerative dermatitis in certain inbred strains, leading to self‑inflicted wounds and secondary infection.
Environmental factors, such as poor husbandry, overcrowding, and inadequate nutrition, exacerbate many of these conditions. Regular health monitoring, strict biosecurity, and appropriate veterinary intervention are essential to maintain colony health and experimental validity.