What is life cycle of trypanosomiasis?
The life cycle of Trypanosoma cruzi involves two intermediate hosts: the invertebrate vector (triatomine insects) and the vertebrate host (humans) and has three developmental stages namely, trypomastigotes, amastigotes and epimastigotes [8].
What is the life cycle of a tsetse fly?
Female tsetse mate just once. After 7 – 9 days she produces a single egg which develops into a larva within her uterus. About nine days later, the mother produces a larva which burrows into the ground where it pupates.
Which stage of the trypanosome life cycle typically infects humans?
Second stage or neurological? phase: this stage begins when the trypanosome parasites cross from the blood-brain barrier into the spinal fluid, infecting the central nervous system including the brain.
What is the progression of African trypanosomiasis?
Infection occurs in two stages, an initial haemolymphatic stage followed by a meningoencephalitic stage after the trypanosomes invade the central nervous system (CNS). However, many of the signs and symptoms are common to both stages, making it difficult to distinguish between the two stages by clinical features alone.
What are the Control of Trypanosomiasis?
There is no vaccine or drug for prophylaxis against African trypanosomiasis. Preventive measures are aimed at minimizing contact with tsetse flies. Local residents in endemic countries are usually aware of the areas that are heavily infested and may be able to provide advice about places to avoid.
What is the infective stage of Trypanosoma?
The infective stage happens in salivary glands. There they undergo the transformation and the product formed is a somewhat short and stumpy infective stage. Then after becoming infected, they are passed onto humans through biting and infection occurs.
How many stages does a tsetse fly undergo?
As with other flies, the larva in Glossinapasses through several stages or instars, as it grows. There are three larval instars in Glossina up to the time when the fully grown larva is dropped by the female fly: the first, second and third instars. The larva has a mouth at the anterior end, and two posterior spiracles.
How is trypanosomiasis spread?
How is East African trypanosomiasis spread? A person will get East African trypanosomiasis if he or she is bitten by a tsetse fly infected with the Trypanosoma brucei rhodesiense parasite. The proportion of tsetse flies that are infected with this parasite is low. The tsetse fly is found only in rural Africa.
What is the infective stage of trypanosomiasis?
In the salivary glands, some parasites detach and undergo transformation into short and stumpy trypomastigotes. These become the infective metacyclic trypomastigotes. They are injected into the mammalian host along with the saliva on biting. Complete development in the fly takes about 20 days.
What is the life cycle of Trypanosoma brucei Gambiense?
During a blood meal from an infected mammalian host, a tsetse fly becomes infected with bloodstream trypomastigotes. 6. In the fly’s midgut, the parasites transform into procyclic trypomastigotes and multiply by binary fission.
What is the life cycle of an African trypanosome?
Life Cycle: Inside the host, they transform into bloodstream trypomastigotes , are carried to other sites throughout the body, reach other blood fluids (e.g., lymph, spinal fluid), and continue the replication by binary fission . The entire life cycle of African Trypanosomes is represented by extracellular stages.
What are the two subspecies of trypanosomiasis?
Two subspecies that are morphologically indistinguishable cause distinct disease patterns in humans: T. b. gambiense, causing chronic African trypanosomiasis (“West African sleeping sickness”) and T. b. rhodesiense, causing acute African trypanosomiasis (“East African sleeping sickness”).
How are trypomastigotes different from African trypanosomes?
The bloodstream trypomastigotes do not replicate (different from the African trypanosomes). Replication resumes only when the parasites enter another cell or are ingested by another vector.
How long does it take to get trypanosomiasis from a fly?
Infection occurs in two stages which may sometimes be preceded by the development of a trypanosomal chancre on the site of inoculation within days of being bitten by an infected fly (most commonly occurs with T. b. rhodesiense ).