Question

The vector that spreads sleeping sickness is
(a) Tsetse fly
(b) Anopheles mosquito
(c) Tiger mosquito
(d) Aedes aegypti

Answer 1

Hint: Sleeping sickness is an insect-borne parasitic infection of humans and other animals and also known as African sleeping sickness or African trypanosomiasis. Its causative agent is an organism belonging to the genus Glossina and is most common in rural areas.

Complete answer:
Sleeping sickness is caused by the species Trypanosoma brucei gambiense (TBG) and Trypanosoma brucei rhodesiense (TbR) and are usually transmitted by the bite of an infected tsetse fly.
This tsetse fly is a large, brown, biting fly that acts as both a host and vector for the trypanosome parasites.

Additional Information:
An infected tsetse fly injects metacyclic trypomastigotes into skin tissue while taking blood from a mammalian host. Through the bite, parasites enter the lymphatic system and then pass into the bloodstream. Inside the mammalian host, the parasite gets transformed into bloodstream trypomastigotes, and are carried to other sites throughout the body, reach other body fluids (e.g., lymph, spinal fluid), and continue to replicate by binary fission.
Initially, the primary stage of the disease is characterized by fevers, headaches, itchiness, and joint pains, beginning one to 3 weeks after the bite. Later after weeks to months, the second stage begins with confusion, poor coordination, numbness, and trouble sleeping. Diagnosis is by finding the parasite during a blood smear or within the fluid of a lymph gland. A spinal puncture is usually needed to inform the difference between first and second stage disease.

So, the correct answer is, ’Tsetse fly’.

Note: - Prevention of severe disease involves screening the population at risk with blood tests for TBG.
- Treatment is easier when the disease is detected early and before neurological symptoms occur. Treatment of the first stage has been with the medications pentamidine or suramin. Treatment of the second stage has involved eflornithine or a mixture of nifurtimox and eflornithine for TBG.
- Fexinidazole is a more recent treatment that can be taken by mouth, for either stage of TBG. Without treatment sleeping sickness typically results in death.
- The disease occurs regularly in some regions of sub-Saharan Africa with the population at risk is about 70 million in 36 countries It is classified as a neglected tropical disease.