Trypanosomes: Protozoans of the class KINETOPLASTA Phylum EUGLENOZOA

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1 Trypanosomes: Protozoans of the class KINETOPLASTA Phylum EUGLENOZOA
Order TRYPANOSOMATIDA Family TRYPANOSOMATIDAE Genus Trypanosoma Trypanosoma cruzi

2 Chagas Disease vs African Sleeping Sickness
African trypanosomiasis (sleeping sickess) occurs in 36 sub- Saharan countries Trypanosoma brucei complex: Transmitted in sub-Saharan African due to the range of Glossina (tsetse fly) Trypanosoma brucei gambinese: Western Africa (Chronic) Trypanosoma brucei rhodesiense: Eastern Africa (Acute) 98% of human trypanosomiasis is caused by T. gambinese (approx. 7,000-10,000 cases reported to the WHO each year) Approximately 300 cases of T. rhodesiense are reported to the WHO each year Glossina species bite during the day and both females and males can transmit the disease

3 Chagas Disease vs. African Sleeping Sickness
Trypanosoma cruzi: Vector is the reduviid bug Acute disease may show no presentation or maybe mild. Chronic infections maybe asymptomatic for some people; however % of people will still develop life-threatening symptoms Vertical (up to 13% of stillborns in parts of South America) or horizontal transmission can occur 12 million people are infected with Chagas Disease

4 Trypanosoma brucei

5 Trypanosoma cruzi Stercoraria Life cycle Within the vertebrate host, the amastigote form multiplies fast causing the cell to lyse, then pseudocyst containing multiple amastigotes are found embedded in the tissues

6 Defining Characteristics
Flagella Nucleus Kinetoplast Posses a kinetoplast Single Flagellum Single nucleus Exclusively parasitic

7 Different forms during the lifecycle
Amastigote Paramastigote Promastigote Epimastigote Trypomastigote

8 Different forms during the lifecycle
Determined by position of the flagellum All stages in the genus Trypanosoma Amastigote Paramastigote Promastigote Epimastigote Trypomastigote

9 Many are heteroxenous: They live in two or more hosts
Many are heteroxenous: They live in two or more hosts. In one stage of their lives they live in the blood or tissues of many vertebrates. And in other stages they live in the gut of bloodsucking invertebrates. Since the parasites themselves usually consume blood products, they are referred to as hemoflagellates. The members of this genus are further divided up in two major groups depending on their route of transmission to the vertebrate host. Salivaria and Stercoraria. If the parasites develops in the anterior section of the digestive tract of the insect it is then transmitted by the saliva (Salivaria) when the insect has its bloodmeal. If the parasite develops in the posterior end of the gut (hindgut) it will then be transmitted in the feces (Stercoraria) that will also come in contact with the new host when the insect is taking its blood meal.

10 Today We will observe members of both groups. A salivarian from Africa (Trypanosoma brucei) trasnmitted to mammals by the Tse-tse fly and a stercorarian from South America (Trypanosoma cruzi) transmitted to humans by the kissing bug.

11 Another flagellate: Leishmania
Phylum Euglenozoa Class Kinetoplastida Order Trypanosomatida Family: Trypanosomatidae??? Genus Leishmania Species donovani Also heteroxenous: indirect life cycle, the intermediate host is the sand fly Leishmania is found in 90 countries (primarily in the subtropics and southern Europe Old world: Middle East, Africa, Southern Europe New world: Mexico, Central America, South America, Occasionally in the US Cutaneous: Approx 700,000 cases Visceral: 200, ,000 cases Not all areas require a human host; however some areas do and this is called the anthroponotic cycle 21 of 30 species infect humans Leishmania donovani, L. infantum, L. chagasi: Visceral Leishmania major, L. mexicana, L. tropica: Cutaneous

12 Leishmaniasis Macrophages engulf the entering amastigote, these multiply within until they cause lysis of macrophage, another phage engulfs the released amastigotes, and this is repeated until considerable damage is caused the reticuloendothelial system

13 Defining Characterstics
Two morphological forms Promastigote : in the insect host

14 Defining Characterstics
Two morphological forms Amastigote (in the vertebrate host)

15 T. brucei, trypomastigote
Card agglutination test for trypanosomasis Giemsa’s stain: Methylene blue, eosin, and Azure B  Blood or lymph node fluid is placed on a microscope slide and fixed in methanol for 30 seconds. The slide is then immersed in a 5% Giemsa stain for 20 to 30 minutes. The slide is then rinsed and dried.

16 T. cruzi, trypomastigote
T. cruzi, pseudocysts T. cruzi, trypomastigote Keep the life cycle in mind when observing the slides T. rhodesiense parasite load is much higher than T. brucei T. brucei can be found in the blood, but it may be difficult. Lymph node aspirate is an easier identification method If a patient is positive for the infection, cerebrospinal fluid should be taken from the patient (advantageous for chronic infections)

17 Leishmania, within macrophage
Biopsy of the liver or spleen, direct agglutination assay, lymph node biopsy, or bone marrow biopsy