East African Sleeping Sickness: A Safety Guide for UK Safari Travellers

East African sleeping sickness, medically known as Rhodesiense Human African Trypanosomiasis (HAT), is a parasitic disease found in parts of Eastern and Southern Africa. For UK travellers, the risk is primarily associated with visits to game parks and woodland areas in countries such as Tanzania, Kenya, Malawi, and Zambia.

The disease is caused by the parasite Trypanosoma brucei rhodesiense, which is transmitted to humans via the bite of the tsetse fly. Unlike the more common West African version, which is chronic and can linger for years, the East African form is acute. It progresses much faster, often affecting the heart and central nervous system within a matter of weeks. According to NHS and NICE travel guidelines, while the risk to the average tourist is low, those on safari or working in rural areas must take specific precautions.

Tsetse flies are larger than houseflies and are known for their painful, aggressive bite. They are daytime feeders and are attracted to motion and dark or bright colours—particularly metallic blue. In the UK, we are accustomed to midges or mosquitoes, but a tsetse fly bite is significantly more noticeable and can result in a 'chancre'.

• The Chancre: A large, painful, red sore that may develop at the site of the bite roughly 5 to 15 days after exposure.
• Aggression: Tsetse flies can bite through thin fabrics, so standard lightweight summer clothing may not provide adequate protection.
• Habitat: They are typically found in 'bush' environments, including the acacia trees and scrubland common on safari routes.

Because East African sleeping sickness progresses quickly, recognising the early signs is vital for a good prognosis. Symptoms usually begin within one to three weeks of being bitten. Initially, the parasite lives in the blood and lymph nodes.

First Stage Symptoms

• Fever and Chills: Often intermittent but can be severe.
• Severe Headaches: Often the first sign that the infection is systemic.
• Muscle and Joint Pain: Generalised aching similar to severe flu.
• Lymphadenopathy: Swollen lymph nodes, particularly at the back of the neck.

Second Stage (Neurological) Symptoms

If left untreated, the parasite crosses the blood-brain barrier. This is the stage that gives the disease its name, as it disrupts sleep-wake cycles. Symptoms include profound confusion, personality changes, slurred speech, and eventually, a coma.

Currently, there is no vaccine or prophylactic drug to prevent sleeping sickness. Prevention is entirely focused on avoiding the tsetse fly. When planning a safari from the UK, consider the following advice:

• Wear Neutral Colours: Avoid blue and black clothing, as these colours attract the flies. Opt for khaki, olive, or light brown.
• Choose Heavy-Weight Fabrics: Tsetse flies can bite through thin cotton. Wear medium-weight trousers and long-sleeved shirts.
• Use Insect Repellent: While standard DEET is effective against mosquitoes, it is less effective against tsetse flies. However, it should still be used to prevent other tropical diseases like malaria.
• Inspect Vehicles: Tsetse flies are attracted to moving vehicles. Before boarding a safari jeep, ensure the interior is clear of flies.
• Avoid Bush Areas: If you are on a walking safari, stay in open areas where possible and avoid thickets during the heat of the day.

If you have recently returned to the UK from a safari and notice a large sore at a bite site or begin to feel unwell, you should seek medical advice immediately. While most tropical fevers in returning travellers are related to malaria, sleeping sickness must be ruled out if you were in a known tsetse fly region.

You can speak to a GP online to discuss your travel history and symptoms. An online doctor can provide an initial assessment and, if they suspect a tropical infection, they will refer you urgently to a specialist tropical disease centre, such as the Hospital for Tropical Diseases in London or a local infectious disease unit. NHS guidance emphasises that early intervention is the key to preventing neurological damage.

It is helpful to have your itinerary ready to share with the doctor, including the specific game parks or rural regions you visited, as this helps narrow down the specific risks.

Diagnosing East African sleeping sickness in the UK involves blood tests to identify the parasite under a microscope. If the infection is suspected to have reached the brain, a lumbar puncture may be required. Treatment involves specialised intravenous medications, such as suramin for the first stage or melarsoprol for the second stage. Because these medications are highly specific, treatment must be managed in a hospital setting by specialists in tropical medicine.