BIO 282 Past Questions and Answers

Q1a:
Two important parasites that can be contacted by consuming raw, undercooked, or poorly prepared freshwater fish and crabs:

• Clonorchis sinensis (Chinese liver fluke)
• Paragonimus westermani (Lung fluke)

Q1b:
Differences between dead-end hosts and reservoir hosts:

• Dead-end hosts: Organisms that get infected by a parasite but do not spread the infection to others (e.g., humans in the case of West Nile virus).
• Reservoir hosts: Organisms that harbor the parasite and can transmit it to others (e.g., rodents for Leishmania parasites).

Life cycle differences between Enterobius vermicularis and Wuchereria bancrofti:

• Enterobius vermicularis (Pinworm) has a simple direct life cycle with no intermediate host, while
• Wuchereria bancrofti requires an intermediate host (mosquito) for its life cycle, involving a vector to transmit microfilariae.

Q1d:

• Blood-borne helminth parasite: Plasmodium (causes malaria)
• Ectoparasite with indiscriminate sexual behavior: Pthirus pubis (pubic lice)

Q2a:
Two types of vectors and examples:

• Biological vectors: Mosquito (for malaria), Tsetse fly (for African trypanosomiasis)
• Mechanical vectors: Housefly (for dysentery), Cockroach (for foodborne diseases)

Q2b:
Methods of disease vector control with examples:

• Reducing contact methods: Using mosquito nets or repellents to avoid mosquito bites
• Chemical control: Insecticides like DDT for mosquito control
• Biological control: Using Bacillus thuringiensis bacteria to control mosquito larvae
• Habitat control: Draining stagnant water to eliminate mosquito breeding sites

Q3a:
Functions of microscope parts:

• Objective lenses: Magnifies the specimen at different levels (e.g., 10x, 40x, 100x)
• Revolving nosepiece: Holds the objective lenses and allows switching between different magnifications

Q3b:
Magnification with a 10x eyepiece and 40x objective lens:

• Total magnification = 10x * 40x = 400x

Q4a:
Five characteristic features of medically important arthropods:

1. Exoskeleton
2. Jointed appendages
3. Segmented body
4. Ability to transmit diseases
5. Presence of antennae and compound eyes

Q4b:
Leishmaniasis types:

• Visceral leishmaniasis: Affects internal organs like the spleen and liver
• Cutaneous leishmaniasis: Affects the skin, causing ulcers
• Mucocutaneous leishmaniasis: Affects mucous membranes of the nose, mouth, and throat

Q5a:
Disease transmission table:

• African trypanosomiasis: Vector = Tsetse fly, Cause = Trypanosoma brucei
• Onchocerciasis: Vector = Black fly (Simulium species), Cause = Onchocerca volvulus

Q5b:
Diseases transmitted by:

• Ornithodoros moubata: Relapsing fever (caused by Borrelia)
• Glossina palpalis: African sleeping sickness (caused by Trypanosoma brucei)
• Phlebotomus sandflies: Leishmaniasis (caused by Leishmania species)
• Pubic pthyrus: Pubic lice infestation

Q6a:
Examples of nematodes:

• Tissue nematodes: Onchocerca volvulus (causes river blindness)
• Intestinal nematodes: Ascaris lumbricoides (causes ascariasis)
• Geohelminthes: Hookworm (Ancylostoma duodenale)
• Filarial nematodes: Wuchereria bancrofti (causes elephantiasis)

Q6b:
Procedures for examining:

• Stool for intestinal parasites: Perform a stool microscopy or concentration method to identify eggs, larvae, or cysts
• Blood for malarial parasites: Use a blood smear stained with Giemsa stain to detect the parasite under the microscope