Question

Mention the factors influencing infections caused by diseases.

Answer 1

1. Pathogenicity and virulence of the pathogen: Pathogenicity is the ability of a microorganism to cause disease, while virulence refers to the severity or harmfulness of the pathogen. Virulence is determined by infectivity, invasiveness (ability to enter and grow in host tissues), and toxigenicity (ability to produce toxins) of the pathogen.
2. Susceptibility of the host: This depends on the host's immunity and resistance to infection. Susceptibility varies among individuals, from no resistance to complete resistance to a particular disease.
3. Mode of transmission: Diseases can be transmitted directly (by contact, droplet infection, injuries, animal bites, blood, or placenta) or indirectly through vectors (e.g., mosquitoes, houseflies), vehicles (contaminated water or food), fomites (contaminated objects), airborne routes, or unclean hands.
4. Environmental and hygiene factors: Poor personal and public hygiene, improper disposal of waste and excreta, contaminated food and water, and presence of vectors and their breeding places increase infection risk.
5. Host defense mechanisms: The integrity of protective barriers like skin and mucous membranes, and immune responses affect disease susceptibility.