What illnesses can affect mice? - briefly
Mice can contract bacterial infections (e.g., salmonellosis, pasteurellosis), viral diseases (e.g., mouse hepatitis virus, lymphocytic choriomeningitis virus), parasitic infestations (e.g., pinworm, ectoparasites), and neoplastic conditions such as lymphoma. These ailments affect colony health and experimental reliability.
What illnesses can affect mice? - in detail
Mice are susceptible to a wide range of infectious, neoplastic, metabolic, and genetic disorders that can compromise research outcomes and animal welfare.
Viral agents
- Lymphocytic choriomeningitis virus (LCMV): causes neurological signs, weight loss, and high mortality in immunocompromised colonies.
- Mouse hepatitis virus (MHV): induces enteritis, hepatitis, and encephalitis; strains differ in tissue tropism.
- Sendai virus: produces respiratory distress, nasal discharge, and bronchopneumonia.
- Murine norovirus: generally subclinical but may exacerbate intestinal inflammation in genetically altered mice.
Bacterial pathogens
- Salmonella spp.: leads to septicemia, enteritis, and death, especially in immunodeficient animals.
- Pasteurella pneumotropica: causes respiratory infection, otitis, and conjunctivitis; often persists as a commensal.
- Streptococcus pneumoniae: results in pneumonia and systemic infection.
- Helicobacter spp.: associated with hepatic, gastrointestinal, and reproductive tract lesions.
Parasitic infestations
- Giardia spp.: produces watery diarrhea, dehydration, and weight loss.
- Eimeria spp. (coccidiosis): causes intestinal epithelium damage, hemorrhage, and mortality in severe cases.
- Mycobacterium spp. (e.g., M. avium complex): leads to granulomatous lesions in liver, spleen, and lungs.
Fungal infections
- Candida albicans: opportunistic infection in immunosuppressed mice, presenting with oral thrush and systemic spread.
- Aspergillus spp.: causes respiratory disease and disseminated infection in contaminated environments.
Neoplastic conditions
- Spontaneous lymphoma: common in aged or genetically predisposed strains, presenting with lymphadenopathy and organ infiltration.
- Mammary adenocarcinoma: frequent in certain inbred lines, leading to palpable tumors and metastasis.
- Hepatocellular carcinoma: observed in chemically induced models and some transgenic lines.
Metabolic and endocrine disorders
- Diabetes mellitus: induced by streptozotocin or genetic mutations, characterized by hyperglycemia, polyuria, and weight loss.
- Obesity: resulting from high‑fat diets or leptin pathway mutations, leading to insulin resistance and cardiovascular strain.
- Hypothyroidism: often linked to iodine deficiency or genetic defects, causing reduced growth and lethargy.
Genetic and congenital abnormalities
- Muscular dystrophy (mdx model): progressive muscle degeneration, elevated serum creatine kinase, and reduced mobility.
- Retinal degeneration (rd1, rd10 strains): progressive loss of photoreceptors, leading to blindness.
- Cardiac hypertrophy in transgenic models: presents with enlarged heart, reduced cardiac output, and premature death.
Immunodeficiencies
- Severe combined immunodeficiency (SCID) mice: lack functional T and B cells, highly vulnerable to opportunistic infections.
- Nude (athymic) mice: absent thymus, impaired T‑cell development, predisposed to viral and bacterial pathogens.
Environmental and husbandry‑related illnesses
- Heat stress: causes hyperthermia, dehydration, and mortality in poorly ventilated cages.
- Nutritional deficiencies: lead to anemia, rickets, and impaired growth.
- Toxicant exposure (e.g., heavy metals, pesticides): results in organ dysfunction, reproductive failure, and mortality.
Prompt identification of clinical signs, routine health monitoring, and appropriate biosecurity measures are essential to mitigate these diseases and maintain reliable experimental data.