Medical Parasitology (EEB 3895) Lecture Exam #3

Transcription

1 1 Name December 2016 Medical Parasitology (EEB 3895) Lecture Exam #3 Read through the exam once before you begin. Read the questions CAREFULLY; be certain to provide all of the information requested. The exam consists of two (2) parts (Parts I and II). You must provide answers for each part. However, you are requested to answer only a SUBSET of questions in each part. If you answer more questions than indicated, your answers will be graded in order, and only the number of questions you are required to answer will be graded. Note: for HOST species, the common name is sufficient; for parasite taxa the correct full scientific name is required unless otherwise indicated. Do not use abbreviations for scientific names. YOU HAVE ONE HOUR TO COMPLETE THIS PORTION OF THE EXAM. IF YOU FINISH THIS PORTION BEFORE ONE HOUR YOU MAY TURN THIS EXAM IN AND BEGIN THE SECOND PORTION OF THE EXAM, BUT YOU MAY NOT HAVE THIS EXAM BACK AFTER YOU HAVE TURNED IT IN. Part I. Answer 10 of the following 14 questions (ANSWER ONLY 10!) (8 points each) 1. Albert has just returned from a 2 week internship with the Peace Corps in Africa in a region that is home to all 4 of the following parasite species. Over the course of his trip he slept in crowded huts in villages in a diversity of locations both near fast flowing streams and in deeper jungle situations. He drank water that was unfiltered, walked barefoot much of the time and, sadly, forgot his mosquito net at home. For each of the following parasite species: describe whether he is likely to come down with an infection, and if so how he would have acquired the infection, as well as whether he is likely to exhibit the full extent of the pathology that each species has the potential to cause. a. Wuchereria bancrofti b. Pediculus humanus humanus c. Onchocerca volvulus d. Ancylostoma duodenale

2 2 2. For each of the following parasites identify the life-cycle stage that is infective to the human host (be specific): a. Trichinella spiralis b. Ancylostoma braziliense c. Loa loa d. chiggers e. Ascaris lumbricoides f. Toxocara canis g. Ascaris suum h. Trichuris trichiura 3. Describe how you would go about definitively diagnosing a human infection with each of the following parasite species. In each case be certain to indicate the type of sample you would take and the stage of the parasite you would expect to find. a. Trichiuris trichiura b. Necator americanus c. Onchocerca volvulus

3 3 4. Describe 2 differences and 2 similarities between cutaneous larval migrans and visceral larval migrans. (Hint: consider all aspects of the biology, taxonomy, disease, etc.) Differences: a. b. Similarities: a. b. 5. Identify the site in/on the human host that you would find the ADULT stage of each of the following parasite species: a. Dracunculus medinensis b. Demodex folliculorum c. Ascaris lumbricoides d. Phthirius pubis e. Loa loa f. Wuchereria bancrofti g. Trichinella spiralis h. Pediculus humanus capitus 6. Identify whether each of the following parasites exhibits a monoxenous or a heteroxenous lifecycle. a. Wuchereria bancrofti b. Demodex folliculorum c. Dracunculus medinensis d. Necator americanus e. Sarcoptes scabei f. Phthirius pubis g. any species of flea h. Ancylostoma caninum

4 7. Answer each of the following questions. 4 a. Identify a phylum of parasite in which the outermost layer of the body is a protective cuticle. b. Identify a species that has almost been entirely eradicated from the planet thanks to the generosity of certain drug companies. c. Identify a species in which the microfilaria is the stage infective to the intermediate host. d. Identify a nematode species that is transmitted between hosts only via predation. e. Identify the species of parasite commonly referred to as the whip-worm. f. Identify the phylum of the species that causes scabies. g. Identify a genus of nematode that includes one or more species that are zoonotic in humans. h. Identify the only species of nematode of medical importance with an aquatic life-cycle. 8. a. Of all of the nematode species we have covered, which would be least happy to acquire as an infection? Explain your answer. b. Of all of the nematode species we have covered, if you had to host an infection, would you choose to host? Explain your answer.

5 9. Answer each of the following questions. 5 a. Where in/on the host would you expect to find the pre-j1 stage of Trichinella spiralis? b. Where in/on the host would you expect to find adults of Demodex folliculorum? c. Where in/on the host would you expect to find adults of Loa loa? d. In/on what type of host would you expect to find J2s of Wuchereria bancrofti? e. Where would you expect to find adults of chigger mites? f. Where in/on the human host would you expect to find J3s of Ancylostoma caninum? g. Where in/on the definitive host would you expect to find adults of Wuchereria bancrofti? h. Where in/on the human host would you expect to find J3s of Toxocara canis? 10. Answer each of the following questions. a. Identify a species that is an etiological agent of hookworm disease. b. The etiological agent of Ascariasis belongs to what phylum? c. Identify the species that is the etiological agent of Elephantiasis. d. Identify a species that possesses tarsal claws and sucking mouthparts. e. Identify a species that is the etiological agent of visceral larval migrans. f. Identify a species that may move to higher latitudes in response to climate change. g. Identify a genus that possesses a buccal capsule and cutting plates and sucks blood. h. Identify a taxon that is an etiological agent of "cooties".

6 6 11. Identify and describe in detail a parasitic infection that can likely be avoided by each of the following 2 scenarios. Be sure to name the parasite, discuss the stage of the parasite involved, and also how the action indicated would serve to prevent an infection. a. covering sand boxes in the southern United States b. cooking polar bear meat in the Arctic 12. Describe the pathogenicity associated with each of the following species in humans. Be certain to include pathology in all important sites of infection. a. Ancylostoma duodenale b. Ascaris lumbricoides

7 13. Identify and describe in detail a parasitic infection that can likely be avoided by each of the following 2 scenarios. Be sure to name the parasite, discuss the stage of the parasite involved, and also how the action indicated would serve to prevent an infection. a. filtering drinking water in Africa 7 b. using a mosquito net in Africa 14. Identify 4 zoonotic species and in each case describe conditions under which infections could successfully be transmitted between the natural animal host and a human. a. b. c. d.

8 Part II. Complete 20 cells in the following Table. If you determine that a particular cell does not apply, write as your answer for that cell. Note: each row must represent a DIFFERENT parasite species (1 point per cell). 8 Parasite species Intermediate host (common name is fine) Mode of entry into/onto human host Site occupied by adult in/on definitive host Parasite Phylum egg with J3 large intestine/rectum Necator americanus consumption of copepod with J3 black fly Ascaris lumbricoides Pediculus humanus humanus Trichinella spiralis ******************************************************************************* Bonus point: Describe one important "life rule" that you have learned from taking Medical Parasitology.

9 Part II. Complete 20 cells in the following Table. If you determine that a particular cell does not apply, write as your answer for that cell. Note: each row must represent a DIFFERENT parasite species (1 point per cell). 1 Parasite species Intermediate host (common name is fine) Mode of entry into/onto human host Site occupied by adult in/on definitive host Parasite Phylum Trichuris trichiura egg with J3 large intestine/rectum Necator americanus Penetration of J3 into skin small intestine Dracunculus medinensis copepod copepod with J3 subcutaneous Onchocerca volvulus black fly Bite of black fly with J3 subcutaneous Ascaris lumbricoides egg with J2 large intestine Pediculus humanus humanus crawls Hair of body Arthropoda Trichinella spiralis uncooked muscle with pre-j1 small intestine Bonus point: