VirusA pathogen that generally consists of a nucleic acid molecule in a protein coat, is too small to be seen by light microscopy, and is able to multiply only within the living cells of a host and usually mutate rapidly.
Way of transmission: (1) direct contact with infected human (2) contact with fomites - contaminated objects such as toys or doorknobs - (3) inhalation of virus aerosols. Important Viruses: Ebola, Rabies, HIV, Smallpox |
FungusFungal diseases are caused by fungus found in one's environment. Fungus's feed on organic matter and usually include things like mushrooms and mold.
Way of transmission: (1) fungal diseases are usually transmitted from direct contact between people, (2) but also can be inhaled through the fungal spores. Important Fungal infections: Fungal Meningitis, Athletes foot |
ProtozoaProtozoa are microscopic, one-celled organisms that can be free-living or parasitic in nature. They are able to multiply in humans, which contributes to their survival and also permits serious infections to develop from just a single organism.
Ways of transmission: (1) Through the feces of a human, which will eventually end up in animals that can potentially transport the organism to humans if the meat is uncooked. (2) The organism can also be transferred through a vector (mosquitoes and small fly bites) that drew infected blood from a host. Important Protozoa infections: Amoebiasis, Giardiasis, Isosporiasis |