Difference between revisions of "Trypanosoma"
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[[Category:Tropical Protozoa]] | [[Category:Tropical Protozoa]] | ||
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Revision as of 22:53, 5 June 2011
- Protozoal parasites found in the blood and tissues of vertebrates
- Worldwide distribution
- Causes sleeping sickness in humans
- Particularly seen in sub-Saharan Africa
- Affects cattle production
- Causes Nagana (Wasting disease)
- Divided into two groups depending on the mode of development in the insect vector
- Salivarian
- Multiply in the foregut and proboscis
- Transmitted via inoculation during feeding
- Transmitted by Tsetse flies
- Also known as anterior station development
- Stercorarian
- Multiply in the hindgut
- Infective form migrates to the rectum
- Transmitted via contamination of wounds with insect faeces
- Also known as posterior station development
- Salivarian
- All Trypansomes except for T. equiperdum have arthropod vectors
- T. equiperdum is a venereally transmitted disease
- Non-cyclical transmission can also occur
- Mechanical transmission
- Transferred by interrupted feeding from one host to another
- Usually transmitted by biting flies, e.g. Tabanidae and Stomoxys
Recognition
- Elongated, spindle shaped protozoa
- Between 8 and 39 μm in length
- Flagellate
- Flagellum runs the length of the body attached to the pellicle which forms an undulating membrane
- Kinetoplast present which contains the DNA of the single mitochondrion
Life Cycle
- Undergo morphological transformations in intermediate host before becoming infective for the next host
- Blood-sucking flies ingest trypanosomes whilst taking a blood meal from an infected animal
- Trypanosomes multiply first in the gut of the fly
- Salivarian trypanosomes are transmitted by Tsetse flies
- Trypanosomes pass forward to the salivary glands where they transform into the infective stage
- Inoculated with saliva when Tsetse fly next feeds on a host
- Stercorarian trypanosomes are transmitted by triatomid bugs, tabanids and keds
- Trypanosomes pass back to the rectum
- Next host is infected when skin wounds are contaminated with infected insect faeces