African Trypanosomiasis or Sleeping Sickness

June 2001

Know before you go!

Infectious diseases not necessarily common in Canada can occur and may even be widespread in other countries. Standards of hygiene and medical care may differ from those at home. Before departure, you should learn about the health conditions in the country or countries you plan to visit, your own risk of disease and the steps you can take to prevent illness.

The risk is yours
Your risk of acquiring a disease depends on several factors. They include: your age, gender, immunization status and current state of health; your itinerary, duration and style of travel (e.g., first class, adventure) and anticipated travel activities (e.g., animal contact, exposure to fresh water, sexual contact); as well as the local disease situation.

Risk assessment consultation
The Public Health Agency of Canada strongly recommends that your travel plans include contacting a travel medicine clinic or physician 6 to 8 weeks before departure. Based on your individual risk assessment, a health care professional can determine your need for immunizations and/or preventive medication (prophylaxis) and advise you on precautions to avoid disease.

Some facts from the experts
The information below has been developed and is updated in consultation with Public Health Agency of Canada's Committee to Advise on Tropical Medicine and Travel (CATMAT). The recommendations are intended as general advice about the prevention of African trypanosomiasis for Canadians travelling internationally.

Disease profile

African trypanosomiasis, commonly called sleeping sickness, is a serious parasitic disease that leads to acute or chronic infection of the central nervous system. Parasites of the genus Trypanosoma cause the disease in humans as well as in cattle. If left untreated, the disease is fatal in humans.

Transmission

African trypanosomiasis is transmitted to humans through the bite of an infected tsetse fly, a grey-brown insect the size of a honey bee. Following entry into a human host, the parasitic protozoa - called trypanosomes - multiply in the blood stream and lymph glands, a process that can continue for years in cases of Trypanosoma brucei gambiense. An individual's risk of infection increases as the number of bites received increases. As well, children can become infected by their mothers while still in the womb, causing abortion or perinatal death.

Geographic distribution

The occurrence of African trypanosomiasis is limited to sub-Saharan Africa in areas where the tsetse fly is constantly present (i.e., endemic). However the presence of tsetse flies does not necessarily mean that the disease is present. Two forms of Trypanosoma cause illness in humans in southern Africa:

• Trypanosoma brucei gambiense (or West African trypanosomiasis) is found in the central and western regions of Africa in forests and areas of heavy vegetation by rivers and waterholes;
• Trypanosoma brucei rhodesiense (or East African trypanosomiasis) is found in the southern and eastern regions of the continent in woodland and savannah areas.

Almost 45,000 cases of African sleeping sickness were reported to the World Health Organization (WHO) in 1999, but the WHO believes the real number of cases is between 300,000 and 500,000 cases. In specific villages of many provinces of Angola, the Democratic Republic of Congo and southern Sudan, the prevalence of the disease is 20% to 50%. Sleeping sickness has become the second greatest cause of death, ahead of HIV/AIDS, in those areas.

Another form of trypanosomiasis in humans, known as Chagas disease, occurs in the Americas (American trypanosomiasis).

Symptoms

The bite of tsetse fly can be painful and may develop into a raised red sore, called a chancre. In West African trypanosomiasis (Trypanosoma brucei gambiense), symptoms can take months or years to appear. They include fever, rash, swelling around the eyes and hands, severe headaches, extreme fatigue, swollen lymph nodes, and aching muscles and joints. If the disease is not treated at this stage, it attacks the central nervous system, producing progressive confusion, slurred speech, personality changes, seizures and difficulty in walking and talking. Symptoms progress and lead to death if left untreated. In East African trypanosomiasis (Trypanosoma brucei rhodesiense), symptoms occur 1 to 4 weeks after exposure and are the same as those listed above for the West African variety of trypanosomiasis.

Treatment

Medications are available for the treatment of African trypanosomiasis. Treatment should begin as soon as possible following exposure to arrest the progression of the disease. However, diagnosis of African trypanosomiasis can be challenging, particularly for Trypanosoma brucei gambiense which has a long asymptomatic period, making early treatment difficult. The disease is diagnosed through blood and spinal fluid tests. African trypanosomiasis is always fatal without treatment.

Prevention and personal precautions

There is no vaccine for the prevention of African trypanosomiasis. Therefore, the Public Health Agency of Canada recommends that travellers to areas where the tsetse fly and African trypanosomiasis are endemic should take insect precautions.

Recommendations

Tourists, hunters, game wardens, fishermen and anyone who works in or visits game parks in East and Central Africa are at the greatest risk for illness by East African trypanosomiasis and should take personal insect precautions. The risk of acquiring West African trypanosomiasis increases for travellers if they spend long periods of time in rural areas of West or Central Africa. Travellers to urban areas are not at risk as the tsetse fly is found only in rural locales. The tsetse fly comes out in the early morning and the late afternoon. Insect repellant does not prevent tsetse fly bites.

Personal measures to avoid tsetse flies
Measures to reduce exposure to tsetse flies include:

Protective clothing:

• Wear thick clothing that reduces the amount of exposed skin, such as heavy long-sleeved shirts, long pants, socks and shoes.
• Avoid wearing bright or dark-coloured clothing as these colours attract tsetse flies.

Screens and bed nets:

• Sleep inside screened areas, under a net or in an air-conditioned room.
• Use bed nets that are rectangular in size, impregnated with permethrin* every 6 months and tucked tightly under the mattress before dusk (note: treated bed nets are available in Canada).

Other measures:

• Avoid riding in the back of open vehicles as tsetse flies are attracted to dust churned up by moving vehicles or animal herds.
• Check the inside of all vehicles for tsetse flies before getting in.
• Stay away from bushy areas especially during the heat of the day. Tsetse flies rest in bushes during high heat periods and can bite if disturbed.
• Insect repellent has not been proven to prevent tsetse fly bites.

Some things to think about...

If a traveller develops a fever, headaches and pains in the joints within 1 to 4 weeks after returning from an area where African trypanosomiasis occurs, he/she should seek medical advice immediately and advise the physician of his/her recent travel itinerary.

For more information...

• For information about African trypanosomiasis and maps provided by the World Health Organization, go to: WHO Report on Global Surveillance of Epidemic-prone Infectious Diseases - African trypanosomiasis
  and go to: African trypanosomiasis or sleeping sickness.
  
• For information about African trypanosomiasis from Médécins sans frontières (MSF), go to: www.msf.org/
• For more Know before you go! information, click here.