Trypanosomiasis
Trypanosomiasis, also known as African sleeping sickness, is a tropical parasitic disease primarily transmitted by the tsetse fly, which inhabits rural areas of sub-Saharan Africa. The disease affects the blood, lymphatic system, and, in advanced cases, the nervous system of both humans and animals. Infection can occur through a tsetse fly bite, during pregnancy via the placenta, or through accidental exposure in laboratory settings. Key risk factors include residing in or visiting areas with dense vegetation and water bodies, where tsetse flies are prevalent.
Symptoms of trypanosomiasis can vary, starting with mild signs like fever and fatigue and progressing to neurological issues such as confusion and seizures in later stages. Diagnosis typically requires blood and spinal fluid analysis, often using light microscopy to confirm the presence of the parasite. Treatment involves specific medications based on the disease stage, with some patients needing prolonged monitoring due to the risk of relapse.
Preventive measures focus on minimizing exposure to tsetse flies, such as using protective clothing, avoiding bright colors, and steering clear of dense vegetation. While there is currently no vaccine, efforts by organizations like the World Health Organization aim to control the tsetse fly population through innovative methods, thereby reducing the incidence of this disease.
Trypanosomiasis
- ANATOMY OR SYSTEM AFFECTED: Blood, lymphatic system, nervous system
- ALSO KNOWN AS: African lethargy, African sleeping sickness, Gambian sleeping sickness, trypanosomosis
Definition
Trypanosomiasis is a tropical parasitic disease transmitted by the African tsetse fly, which infects the blood, lymphatic system, and nervous system in humans and animals.
Causes
Trypanosomiasis is caused by a bite from the tsetse fly, an insect found only in sub-Saharan Africa. This fly conveys the Trypanosoma parasite. Trypanosomiasis can also be transferred through the placenta during pregnancy. Additionally, laboratory workers have become infected with trypanosomiasis by accidentally pricking their skin with needles infected with Trypanosoma.
Risk Factors
Because the vector of trypanosomiasis, the tsetse fly, is found only in rural areas of sub-Saharan Africa, those who frequent those areas, and villagers, hunters, and anglers, are at greatest risk. Persons inhabiting rural African woodland and savanna regions, especially near bodies of water and dense vegetation, are most susceptible.
Symptoms
The symptoms of trypanosomiasis include fever, headaches, swollen lymph nodes, extreme fatigue, skin rash, itching, joint and muscle pain, weight loss, confusion, sleepiness, slurred speech, impaired coordination, and altered personality. Neurological symptoms, such as confusion, slurred speech, personality changes, and seizures may occur in later stages.
Screening and Diagnosis
After conducting a physical examination and questioning the patient about symptoms and medical history, a physician will draw blood and spinal fluid samples. Light microscopy of spinal fluid is necessary to confirm trypanosomiasis diagnosis because trypanosomiasis is frequently asymptomatic or manifests mild symptoms in its initial stage, and it is sometimes difficult to discern in blood.
Treatment and Therapy
Five drugs are used to treat trypanosomiasis, depending upon the stage of the illness. Suramin and pentamidine are used to treat trypanosomiasis in its initial stage when it is confined to the blood and lymphatic systems. If trypanosomiasis is advanced and has infected the nervous system, then melarsoprol or eflornithine, sometimes combined with nifurtimox, is administered in a hospital setting. Fexinidazole, an oral medication, has also been introduced. For up to two years after treatment, at three- to six-month intervals, the patient’s spinal fluid is drawn and tested for trypanosomiasis because the patient may relapse or become reinfected, requiring further treatment.
Prevention and Outcomes
The World Health Organization has greatly reduced trypanosomiasis by treating male tsetse flies with radiation—rendering them sterile—then releasing them back into the environment, thereby lowering the number of tsetse flies. Although there is no vaccine or drug that prevents trypanosomiasis, several steps may be taken to reduce the likelihood of infection. In endemic areas, one should use netting or screens around tents or other living areas to barricade against insects. All skin, wherever possible, should be covered by medium-weight clothing to protect against insect bites. Bright and dark colors should be avoided because tsetse flies are attracted to those colors; one should instead wear light colors.
Tsetse flies bite during the daytime, but they repose in bushes during the hottest part of the day, so bushes and dense vegetation should be avoided if possible. Because tsetse flies are attracted to swirling dust created by moving vehicles on the African savanna, vehicles should be examined carefully for tsetse flies before being entered.
Bibliography
Dumas, Michel, Bernard Bouteille, and Alain Buguet, editors. Progress in Human African Trypanosomiasis, Sleeping Sickness. Springer, 1999.
Elenga, Viny Aurélien, et al. "Risk Factors and Prevalence of Human African Trypanosomiasis in Individuals Living in Remote Areas of the Republic of Congo." BMC Public Health, vol. 22, no. 1, 2022, p. 2322, doi.org/10.1186/s12889-022-14577-9. Accessed 4 Nov. 2024.
Hollingshead, Caitlyn, and Rene Bermudez. "Human African Trypanosomiasis (Sleeping Sickness) - StatPearls." NCBI, 24 Feb. 2024, www.ncbi.nlm.nih.gov/books/NBK535413. Accessed 4 Nov. 2024.
Kruel, Donald. Deadly Diseases and Epidemics: Trypanosomiasis. Chelsea House, 2007.
Maudlin, I., P. H. Holmes, and M. A. Miles, editors. The Trypanosomiases. CABI, 2004.
Papagni, Roberta, et al. "Human African Trypanosomiasis (Sleeping Sickness): Current Knowledge and Future Challenges." Frontiers in Tropical Diseases, vol. 4, 2023, p. 1087003, doi.org/10.3389/fitd.2023.1087003. Accessed 4 Nov. 2024.
"Trypanosomiasis, Human African (Sleeping Sickness)." World Health Organization (WHO), 2 May 2023, www.who.int/news-room/fact-sheets/detail/trypanosomiasis-human-african-(sleeping-sickness). Accessed 4 Nov. 2024.