Question

Meet the African Sleeping Sickness What is another medical term for African Sleeping Sickness?ii. Signs and symptoms of disease:iii. How do humans get contract disease (i.e. how is it transmitted)?iv. Describe the course of the disease:v. How can this infection be prevented in humans?vi. Type of parasite (bacteria, protozoan, fungus, helminth, insect, virus): vii. Scientific name of parasite (properly formatted): viii. How does this parasite evade the host’s immune system?ix. List the order in which you placed the life cycle circles in the Adopt a Pet Parasite game (There is a sentence associated with each of the 4 circles.):1.2.3.

Answer 1

i.African sleeping sickness is also known as African Trypanosomiasis or sleeping sickness caused by a insect borne parasite.It affects both humans and animals.The vector of this disease tsetse fly is only found in the Sub Saharan Africa.It is known as sleeping sickness because there will be disturbed sleep pattern.This disease mainly affects the remote rural population of africa.

ii.There are two stages of this disease.The initial haemo lymphatic stage and meningoencephalitic stage.But the symptoms of both the stages are almost common.Early symptoms are fever,joint pain,itching and headache followed by behavioural changes,confusion,difficulties with speech etc.In the haemo lymphatic stage,they multiply in the blood,lymph and subcutaneous tissues ab=nd cause symptoms like fever,itching,enlarged lymph nodes,joint pain etc.In the meningocephalitis stage,this parasite infect the central nervous system.This causes clear symptoms like disturbance in sleep,poor coordination of activities,behavioral changes,sensory disturbances etc.Diagnosis is made by performing serological test in which the presence os parasite is detected in the blood smear or fluid from lymph.

iii.Sleeping sickness is occurs in both human and animals by the bite of tsetse fly(Gossypian species).Animals can be the host of this pathogen affection human.In human two species :Trypanosoma brucei and Trypanosome brucei rhodesiense.This is a vector borne disease.It is transmitted in humans through the bite of tsetse fly which have got the infection after biting a infectious human or animals with this parasite.THis can be transmitted from an infected mother to child through placenta.Accidental transmission by the use of contaminated needles.There are reports of transmission of this disease through sexual contact with infected person,blood transfusion,from blood sucking insects etc.But these cases are rare and mainly transmitted by the bite of tsetse fly.

iv.This disease is short term acute illness and last for some weeks to few months.It is curable if diagnosed earlier but fatal if left untreated.The Trypanosome lifecycle in the human body is as follows:

• The parasite is injected to the body by the bite of tsetse fly.
• At this stage,the parasite is in infective form called metacyclic trypomastigotes with a short flagellum.
• In the bloodstream they transform into trypomastigotes with long flagellum that spread rapidly in the body.
• These trypomastigotes multiply in lymph,blood and spinal fluid.
• The next stages of lifecycle is completed in the tsetse fly.Inside the midgut of fly,they transform into epimastigotes that is injected to another host in the next bite.

v.Sleeping sickness is curable if treated in the early stages.The drugs used to treat this disease are pentamidine,suramine,melarsoprol,eflornithine.The disease infection can be prevented if some precautions are taken.They are:

• There is no vaccine discovered to protect against this parasite.So the only way is to minimize the contact with tsetse fly.
• Wear long sleeve shirts and trousers to protect from the bite.
• Use neutral colored clothes as tsetse fly is attracted to bright colours.
• Use insect repellent creams and lotions.
• Reduce the population of tsetse fly using insecticides and flytraps.
• Use bed nets while sleeping.

vi.Trypanosomes are protozoans belonging to the genusTrypanosoma.They are unicellular parasite.

vii.African Trypanosomiasis is caused by the parasite Trypanosoma brucei.The two forms of this species that infect humans are:Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense.

viii. These protozoan parasite invade the immune syssyem.They have the ability to change the surface glycoprotein called antigen variation.The consequence is that exposing multiple antigens can cause difficulty in antibody production and disease remains unknown.