Trypanosoma lewisi
| Trypanosoma lewisi | |
|---|---|
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| Trypanosoma lewisi | |
| Scientific classification | |
| Domain: | Eukaryota |
| (unranked): | Excavata |
| Phylum: | Euglenozoa |
| Class: | Kinetoplastida |
| Order: | Trypanosomatida |
| Genus: | Trypanosoma |
| Species: | T. lewisi |
| Binomial name | |
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Trypanosoma lewisi |
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Trypanosoma lewisi is a parasite of Rattus species and other rodents such as mice and kangaroo rats in America. Among these host species are two endemic species of rats: Rattus macleari, now believed to be extinct, and Rattus nativitatis. It is not very clear whether or not the same lewisi parasite infects both species. However, both parasites are very similar. The northern rat flea, Nosopsyllus fasciatus acts as the vector for the parasite, harboring the epimastigote stage in its midgut. The trypomastigote is the stage that is present in the main host, the rodent. The epimastigote form attaches itself to the rectum of the insect using its flagella to burrow through the rectal walls. The parasites also appear in the flea's feces. Ingestion of either the flea or its feces during grooming infects the host rodent with the parasites.T. lewisi is normally non-pathogenic but is known to have produced fatal infections in rats.
Trypanosomes in the blood of rats were first noted and described by Timothy Richards Lewis from Calcutta and the species was named after him. In the 1900s, a parasitologist noticed that Rattus macleari, a species of rat endemic to Christmas Island, were becoming sick. The suspected cause was a species of trypanosomes. There was no proof that this was actually correct until scientists from the American Museum of Natural History deposited some rats that had been collected from Christmas Island as specimens into museums. Scientists argue that Trypanosoma lewisi is partially or wholly responsible for the subsequent extinction of Rattus macleari. The parasites were transmitted from fleas infesting the then recently introduced black rats (Rattus rattus).
T. lewisi can be cultured in various media including in vivo in rat serum and in vitro in mammalian cell culture media. The parasite can also be grown in mice if the host is supplemented with a controlled diet and intraperitoneal injection of rat serum. Ablastin, an antibody that arises during an infection in the host’s body, prevents the parasite from reproducing although they remain in adult form.
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Wikipedia