Parasitology is the branch of biology that studies parasites and parasitic diseases, including their distribution, biochemistry, physiology, molecular biology, ecology, evolution, and clinical aspects, as well as the host's reaction to these pathogens. Viruses, bacteria, fungi, protozoa, worms, insects, and arachnids are regarded as parasitic organisms. Since vaccinations are controversial and we're in the post-antibiotic era of antibiotic-resistant superbugs and superinfection, the best antiparasitic are hygiene, nutrition, and cardiovascular exercise.
Public health is a discipline of science that focuses on the surveillance, control, identification, and prevention of infectious disease outbreaks and transmission in a defined human population.