Final answer:
Historical research on helminths and protozoa has been pivotal for the development and availability of treatments for related diseases. Studies in microbiology have led to a reduction in certain diseases, such as guinea-worm disease, and understanding the wider health impacts of these parasites.
Step-by-step explanation:
The historical research focus on helminths and protozoa has significantly influenced the development and availability of treatments for diseases caused by these organisms. Protozoan infections require specialized antiprotozoal drugs as these pathogens exhibit great biological diversity. Plasmodium species, responsible for malaria, are becoming resistant to many antimalarial drugs. Helminthic infections, on the other hand, are treated with different drugs targeted at adult worms, leading to their elimination via feces.
Helminths, including parasitic worms like guinea worms, are studied in microbiology due to their microscopic eggs and larvae. Researching these organisms has led to significant public health outcomes, such as the nearly complete eradication of guinea-worm disease, dropping from 3.5 million cases to just 126 in 2014 due to coordinated water sanitation efforts. The study of these parasites, including helminths, and their impact on infections of the GI tract, falls within the field of microbiology. Comparing their characteristics aids in understanding not only the infections they cause but also their broader health implications, including the potential exacerbation of other diseases like the plague due to helminth-induced changes in the immune system.