Infectious diseases |
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These occur due to external (extrinsic) factors. | These generally occur due to internal (intrinsic) factors. | |
These are cause by the attack of pathogens (viruses, bacteria, fungi, protozoans, worms) | These are caused by factors other than living pathogens. | |
Infection is transmitted through direct contact (physical contact, sexual contact) or through medium (air, water, food, insects etc.) | Infection is not transmitted through direct contact or through medium except in medium hereditary diseases where it occurs from parent offspring. |