1Q. According to the CDC, what are the leading causes of death in the US? Do
bacteria, viruses, or parasites cause many of these diseases? Why should we care
1A. Heart disease, cancer, lower respiratory disease, stroke, diabetes, and
accidents. Lower respiratory disease is caused by bacterial pneumonia and we
should care about parasites because more than 2 billion people travel b y air and
can easily spread parasites.
2Q. According to the WHO, what are the leading causes of death in
underdeveloped countries? Give some examples of “neglected” infectious
2A. Heart disease, lower respiratory disease, HIV/AIDS, diarrheal diseases, TB,
Malaria, and measles. Examples are intestinal parasites, leprosy, and
3Q. Why are diseases in underdeveloped parts of the world a threat to us in the
United States? What is the best strategy for fighting parasitic infections?
3A. These diseases are a threat because of the amount of people who travel and
these diseases spread very easily and the best strategy is health education.
4Q. What is a parasite? For each of the following, identify whether it could be a
parasite according to the traditional definition.
4A. A parasite is a species that has a metabolic dependence and ecological
relationship with a host. A cestode, trematode, nematode, protozoan, and
arthropod are all parasites. Bacteria, virus, and fungus are not parasites.
5Q. What is a symbiosis? What is each participant in a symbiotic relationship
5A. Symbiosis is the association of organisms of different species called symbionts.
6Q. What type of dependency exists between the participants of a phoretic
relationship? Does the phoront benefit from the relationship?
6A. The phoront is carried by the larger symbiont, which benefits from dispersal
and there is no effect on the host; no physiological or biochemical dependency.
7Q. Explain commensalism. How does the commensal benefit? Can these
organisms survive independently?
7A. It involves food not transport that is consumed by the host and the organism
can survive alone.
8Q. What is mutualism? Can these partners survive independently? What type of
dependence exists between the partners? Give some examples.