Health, disease and the development of medicines study guide

Pathogens, including bacteria, fungi, protists, and viruses, exhibit diverse methods of transmission, leading to widespread infection. Understanding these methods is crucial for reducing or preventing their spread. Cholera, caused by bacteria, is primarily waterborne, transmitting through contaminated water sources. Prevention involves ensuring access to clean drinking water and proper sanitation. Tuberculosis (TB), another bacterial disease, is airborne: it spreads via tiny droplets released into the air when an infected person coughs or sneezes. Reducing TB spread includes isolation of infected individuals and vaccination. Chalara ash dieback, a fungal disease affecting ash trees, is also airborne, with spores carried by wind. Control measures focus on restricting movement of infected plant material and removing diseased trees. Malaria, caused by protists, relies on animal vectors, specifically mosquitoes, to transmit the pathogen between hosts. Preventing malaria involves mosquito control (e.g., insecticides, nets) and antimalarial drugs. Helicobacter pylori, bacteria causing stomach ulcers, spreads via oral transmission, often through contaminated food or water or close contact. Good hygiene and sanitation are key to prevention. Ebola, a viral disease, spreads through direct contact with body fluids of an infected person or contaminated objects. Strict infection control measures, safe burial practices, and rapid isolation of cases are essential to contain Ebola outbreaks.

A pathogen is any microorganism that causes disease in plants or animals. The main groups of pathogens are viruses, bacteria, fungi, and protists. Viruses are non-cellular entities that invade and reproduce within host cells, often killing them in the process. Bacteria are single-celled prokaryotes that can multiply rapidly and cause harm by releasing toxins or damaging tissues. Fungi include both single-celled organisms like yeasts and multicellular forms like moulds; they can infect hosts by invading tissues or producing enzymes that break down cells. Protists are single-celled eukaryotes, some of which act as parasites by living inside host organisms and disrupting normal function. Each group of pathogen causes infectious disease by a unique mechanism.