48 Questions
Where do the tsetse flies transmitting T. brucei prefer for reproduction?
Shaded stream banks
What is the range of Trypanosoma brucei limited to?
Tropical west and central Africa
What is the most frequently and severely affected tissue in Trypanosoma cruzi infection?
Cardiac muscle
Where is human disease caused by T. cruzi found most often?
South and Central America
What are the clinical diseases associated with Leishmania tropica, Leishmania donovani, and Leishmania braziliensis?
Cutaneous leishmaniasis, Visceral leishmaniasis, Mucocutaneous leishmaniasis
Describe the two forms in which Leishmania species exist in their life cycle.
Amastigote (aflagellar) and Promastigote (flagellated)
Which organs are most severely affected in visceral leishmaniasis?
Liver, Spleen, Bone marrow
Where does the amastigote multiply in the human body during Leishmania donovani infection?
Reticuloendothelial system of the viscera
What is the vector for Trypanosoma brucei, the etiologic agent of African trypanosomiasis?
Tse tse fly
Describe the typical structure of a trypanosome.
An elongated spindle-shaped body that tapers at both ends, a centrally situated nucleus, a kinetoplast posterior to nucleus, an undulating membrane arising from the kinetoplast, and a single free flagellum at the anterior end.
How is mucocutaneous leishmaniasis diagnosed in the laboratory?
Demonstration of the amastigotes in properly stained smears from touch preparations of ulcer biopsy specimen.
What is the progression of African trypanosomiasis (sleeping sickness) in terms of symptoms?
Typical somnolence (sleepiness) progresses to coma as a result of demyelinating encephalitis.
Where are Leishmania tropica parasites found in the body?
Endothelial cells of the capillaries, nearby lymph nodes, within large mononuclear cells, in neutrophilic leukocytes, and free in the serum exuding from the ulcerative site.
What is the pathogenesis of Leishmania braziliensis mucocutaneous leishmaniasis?
Lesions are confined to the skin in cutaneous leishmaniasis and to the mucous membranes, cartilage, and skin in mucocutaneous leishmaniasis. A granulomatous response occurs, and a necrotic ulcer forms at the bite site.
Where is cutaneous leishmaniasis produced by L. tropica complex present?
Many parts of Asia, Africa, Mediterranean Europe, and the southern region of the former Soviet Union.
What is the fate of the lesions in mucocutaneous leishmaniasis?
The lesions tend to become superinfected with bacteria, and secondary lesions occur on the skin as well as in mucous membranes.
What are the two forms in which Leishmania species exist in their life cycle?
Amastigote (aflagellar) and promastigote (flagellated)
Which organs are the most severely affected in visceral leishmaniasis?
Liver, spleen, and bone marrow
What is the natural habitat of Leishmania donovani in the human body?
Reticuloendothelial system of the viscera
What is the classic name for Leishmania donovani infection also known as DumDum fever or Kalazar?
Kala-azar ('black sickness')
What are the initial lesions like in mucocutaneous leishmaniasis?
Polypoid
How is mucocutaneous leishmaniasis diagnosed in the laboratory?
Demonstration of the amastigotes in properly stained smears
What is the vector for Trypanosoma brucei, the etiologic agent of African trypanosomiasis?
Tse tse fly
What is the typical progression of African trypanosomiasis (sleeping sickness) in terms of symptoms?
Somnolence progressing to coma
Where are Leishmania tropica parasites found in the body?
Endothelial cells of the capillaries of the infected site, nearby lymph nodes, within large mononuclear cells, in neutrophilic leukocytes, and free in the serum exuding from the ulcerative site.
What is the pathogenesis of Leishmania donovani infection in macrophages?
The introduced parasites round up to form amastigote and multiply.
Where is mucocutaneous leishmaniasis mainly confined to in the body?
Mucous membranes, cartilage, and skin.
What regions are affected by cutaneous leishmaniasis produced by Leishmania tropica complex?
Many parts of Asia, Africa, Mediterranean Europe, and the southern region of the former Soviet Union.
What is the preferred habitat for tsetse flies transmitting T. brucei for reproduction?
Shaded stream banks
What is the most frequently and severely affected tissue in Trypanosoma cruzi infection?
Cardiac muscle
Where is human disease caused by T. cruzi found most often?
South and Central America
What is the vector for Trypanosoma cruzi, the etiologic agent of American trypanosomiasis?
Triatomid bug
Describe the characteristics of Entamoeba coli.
Nonpathogenic, larger than histolytica, contains ingested bacteria but no red cells, visible nucleus with large eccentric karyosome.
What are the distinguishing features of Endolimax nana?
Small trophozoite size, inconspicuous or absent chromidial bars in cyst, nonpathogenic.
Discuss the characteristics of Iodamoeba butschlii.
Small trophozoite size, prominent nucleus with bull's eye appearance, widely distributed.
What are the key differences between Entamoeba coli and Endolimax nana?
Entamoeba coli is larger, contains ingested bacteria but no red cells, while Endolimax nana has a small size and inconspicuous chromidial bars.
What is the preferred habitat for tsetse flies transmitting Trypanosoma brucei for reproduction?
Shaded stream banks
Where is Trypanosoma cruzi found most often in terms of human disease?
South and Central America
What is the most frequently and severely affected tissue in Trypanosoma cruzi infection?
Cardiac muscle
What is the method for concentrating parasites in blood that may be helpful for diagnosis of Trypanosomiasis?
Centrifugation of heparinized samples and ion-exchange chromatography
Where are Leishmania tropica parasites found in the body?
Endothelial cells of the capillaries of the infected site, nearby lymph nodes, within large mononuclear cells, in neutrophilic leukocytes, and free in the serum exuding from the ulcerative site.
What is the location of mucocutaneous leishmaniasis?
Mucocutaneous leishmaniasis is the same as oriental sore, but some strains tend to invade the mucous membranes of the mouth, nose, pharynx, and larynx.
What is the pathogenesis of Leishmania braziliensis mucocutaneous leishmaniasis?
The lesions are confined to the skin in cutaneous leishmaniasis and to the mucous membranes, cartilage, and skin in mucocutaneous leishmaniasis. A granulomatous response occurs, and a necrotic ulcer forms at the bite site.
What regions are affected by cutaneous leishmaniasis produced by Leishmania tropica complex?
Cutaneous leishmaniasis produced by L. tropica complex is present in many parts of Asia, Africa, Mediterranean Europe, and the southern region of the former Soviet Union.
What is the vector for Trypanosoma brucei, the etiologic agent of African trypanosomiasis?
Tse tse fly
How is mucocutaneous leishmaniasis diagnosed in the laboratory?
Demonstration of amastigotes in properly stained smears from touch preparations of ulcer biopsy specimen.
Describe the typical structure of a trypanosome.
An elongated spindleshaped body that tapers at both ends, a centrally situated nucleus, a kinetoplast posterior to nucleus, an undulating membrane, and a single free flagellum.
What is the pathogenesis of African trypanosomiasis (sleeping sickness)?
Trypomastigotes spread from the skin through the blood to the lymph node and brain, leading to somnolence progressing to coma due to demyelinating encephalitis.
Study Notes
- Hemoflagellates are a type of protozoan parasites with different forms based on the position of their kinetoplast and flagellum.
- Leishmania is a genus of hemoflagellates, responsible for causing various clinical diseases.
- Leishmania species include: Leishmania tropica, Leishmania donovani, and Leishmania braziliensis.
- Leishmania exist in two forms, amastigote (aflagellar) and promastigote (flagellated), in their life cycle.
- Leishmania parasites are transmitted by certain species of sand flies (vectors).
Leishmania donovani:
- Natural habitat: Reticuloendothelial system of the viscera.
- Organs affected: Liver, spleen, and bone marrow.
- Clinical manifestations: Enlarged spleen and liver, anemia, lymphadenopathy.
- Epidemiology: Present in Asia, Africa, and Southeast Asia.
- Laboratory diagnosis: Examine tissue biopsy, spleen aspiration, bone marrow aspiration, or lymph node aspiration for amastigotes in a stained smear. Serologic testing is also available.
Leishmania tropica:
- Found in endothelial cells of the capillaries, nearby lymph nodes, large mononuclear cells, neutrophilic leukocytes, and free in the serum.
- Metastasis to other sites or invasion of the viscera is rare.
- Pathogenesis: Phagocytosis in neutrophilic leukocytes is usually successful, but in macrophages, parasites round up and multiply.
- Epidemiology: Present in Asia, Africa, Mediterranean Europe, and the southern region of the former Soviet Union.
Leishmania braziliensis:
- Mucocutaneous leishmaniasis involves the same lesions as oriental sore.
- Some strains tend to invade mucous membranes of the mouth, nose, pharynx, and larynx.
- Pathogenesis: Confined to skin in cutaneous leishmaniasis and mucous membranes, cartilage, and skin in mucocutaneous leishmaniasis.
- Epidemiology: Found in the Yucatan peninsula into Central & South America, especially in rain forests where workers are exposed to sand fly bites while invading the habitat of forest rodents.
Trypanosomiasis:
- Caused by Trypanosoma brucei and Trypanosoma cruzi.
- Trypanosoma brucei: African trypanosomiasis (sleeping sickness), limited to tropical west and central Africa, vector is the tsetse fly.
- Trypanosoma cruzi: American trypanosomiasis (Chagas' disease), widespread in Triatomid bugs and a broad spectrum of reservoir animals, vector is the triatomid bug.
Learn about the nasal, oral, and pharyngeal lesions associated with mucocutaneous leishmaniasis, as well as the epidemiology of the disease. Explore how the disease spreads in regions like the Yucatan peninsula and Central & South America, and its impact on both humans and animals.
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