Describe a transmissible disease as a disease in which the pathogen can be passed from one host to another

SouravNovember 4, 2024

Answer

Transmissible diseases, often referred to as communicable diseases, are illnesses caused by pathogens that can be passed from one host to another. These pathogens include bacteria, viruses, fungi, and protozoa, and they can spread through various mechanisms.

Modes of Transmission

1. Direct Transmission: This occurs when an infected individual directly transfers the pathogen to a susceptible person. Common methods include:
   • Physical Contact: Such as shaking hands or kissing (e.g., herpes simplex virus).
   • Droplet Spread: When an infected person coughs or sneezes, releasing droplets that can be inhaled by others (e.g., influenza, measles).
2. Indirect Transmission: This involves the transfer of pathogens through an intermediary, which can include:
   • Vectors: Organisms like mosquitoes or ticks that carry pathogens from one host to another (e.g., malaria is transmitted by mosquitoes).
   • Fomites: Contaminated surfaces or objects that harbor pathogens (e.g., noroviruses on kitchen counters).
   • Airborne Transmission: Pathogens that remain suspended in the air and can infect individuals over distances greater than one meter (e.g., tuberculosis).
3. Other Routes: Pathogens can also spread through:
   • Bodily Fluids: Such as blood or sexual fluids (e.g., HIV, hepatitis).
   • Contaminated Food and Water: Ingestion of food or water contaminated with pathogens (e.g., cholera).

Characteristics of Transmissible Diseases

• Infectious Nature: Transmissible diseases are inherently infectious, meaning they can cause disease upon entering a susceptible host.
• Asymptomatic Carriers: Some individuals may carry and transmit pathogens without showing symptoms (e.g., asymptomatic carriers of hepatitis B).
• Environmental Factors: The environment plays a crucial role in the transmission cycle, providing conditions for pathogens to survive and spread .