Disease causative agents are biological pathogens—primarily viruses, bacteria, fungi, protozoa, and helminths—that invade a host to cause infection and illness. These microorganisms, alongside external toxins, trigger diseases like COVID-19, influenza, and tuberculosis. They spread through person-to-person contact, contaminated surfaces, or vectors.Main Types of Disease Causative Agents
- Viruses: Non-living agents that require a host cell to replicate (e.g., Influenza, HIV, SARS-CoV-2).
- Bacteria: Single-celled microorganisms that can cause infections (e.g., E. coli, Salmonella, Tuberculosis).
- Fungi: Organisms that can cause infections of the skin, lungs, or other areas (e.g., Candida).
- Protozoa: Unicellular parasites that often cause gastrointestinal issues (e.g., Giardia, Plasmodium causing malaria).
- Helminths: Parasitic worms.
- Prions: Infectious proteins that cause neurodegenerative diseases.
Key Concepts
- Pathogenicity: The ability of an agent to cause disease.
- Transmission: Agents spread through direct contact, aerosols, food/water, or vectors.
- Epidemiologic Triad: Diseases are modeled using the interaction between the agent, the host (human), and the environment.
Other, non-biological agents include chemical contaminants or physical forces (e.g., radiation) that lead to injury or illness.
1.Viruses
Vimelea aina ya virusi usababisha magonjwa yasiyotibika ,
Hivyo yanahitaji chanzo Kama newcastle , fowl pox , infection bursal disease
2.Bacteria
Vimelea wengine kama bacteria wanaosababisha magonjwa kama fowl typhoid , fowl chorela , infection coryza
3.Uchafu wa mazingira
Usababisha visumbufu kama vile chawa , viroboto , minyoo , papasi ,
4.Lishe duni
Ajali ya lishe duni upelekea upungufu wa kinga na mahitaji ya mwili
Uweza kusababisha matatizo Kama vile matege , kuvunjika mifupa