What diseases do rats not get? - briefly
Rats are not natural hosts for human‑specific viral infections such as HIV, measles, smallpox, and polio, nor do they develop malaria because they lack the appropriate parasite vectors. They also rarely acquire diseases that depend on species‑specific receptors, including hepatitis B and certain influenza strains.
What diseases do rats not get? - in detail
Rats are resistant to a number of pathogens that cause disease in humans and other mammals because the organisms cannot enter rat cells, replicate, or evade the rodent immune system.
Human‑specific viruses that fail to infect rats include:
- Human immunodeficiency virus (HIV). Rat cells lack the CD4 and CCR5/CXCR4 receptors required for viral entry, so replication does not occur.
- Hepatitis B and C viruses. Absence of the NTCP and CD81 receptors prevents viral attachment and internalisation.
- Measles, mumps and rubella viruses. Species‑specific receptor usage and intracellular restriction factors block the infection cycle.
- Variola (smallpox) virus. The virus is adapted to human epidermal cells; rat skin cells do not support its replication.
- Poliovirus. Rat cells are non‑permissive for the viral RNA translation machinery, resulting in abortive infection.
Vector‑borne parasites that complete their life cycles in humans but not in rats comprise:
- Plasmodium falciparum (malaria). The parasite cannot develop within rat erythrocytes, so rats are not natural hosts.
- Dengue and yellow fever viruses. Mosquito‑borne flaviviruses require human or primate cellular factors absent in rats.
Certain bacterial diseases also fail to establish in rats:
- Corynebacterium diphtheriae (diphtheria). The toxin does not bind rat epithelial receptors, preventing disease manifestation.
- Treponema pallidum (syphilis). The organism shows limited survival in rat tissue and does not cause the characteristic lesions.
These exclusions arise from differences in receptor expression, intracellular signaling pathways, and immune surveillance mechanisms that collectively render rats unsuitable hosts for the listed agents.