African trypanosomiasis overview: Difference between revisions
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African trypanosomiasis can be classified based upon the pathogen and geographic location into two types East African trypanosomiasis and West African trypanosomiasis.<ref name="pmid16308383">{{cite journal |vauthors=Picozzi K, Fèvre EM, Odiit M, Carrington M, Eisler MC, Maudlin I, Welburn SC |title=Sleeping sickness in Uganda: a thin line between two fatal diseases |journal=BMJ |volume=331 |issue=7527 |pages=1238–41 |year=2005 |pmid=16308383 |pmc=1289320 |doi=10.1136/bmj.331.7527.1238 |url=}}</ref> | African trypanosomiasis can be classified based upon the pathogen and geographic location into two types East African trypanosomiasis and West African trypanosomiasis.<ref name="pmid16308383">{{cite journal |vauthors=Picozzi K, Fèvre EM, Odiit M, Carrington M, Eisler MC, Maudlin I, Welburn SC |title=Sleeping sickness in Uganda: a thin line between two fatal diseases |journal=BMJ |volume=331 |issue=7527 |pages=1238–41 |year=2005 |pmid=16308383 |pmc=1289320 |doi=10.1136/bmj.331.7527.1238 |url=}}</ref> | ||
==Pathophysiology== | ==Pathophysiology== | ||
African trypanosomiasis is a human tropical parasitic disease usually caused by a protozoan hemoflagellates belonging to the complex Trypanosoma brucei. Infection is usually transmitted via the tsetse fly bite to the human host. A trypanosomal chancre develops on the site of inoculation. This is followed by a hemolymphatic stage with symptoms that include fever, lymphadenopathy, and pruritus. In the meningoencephalitic stage, invasion of the central nervous system can cause headaches, somnolence, abnormal behavior, and lead to loss of consciousness and coma. The course of infection is much more acute with T. b. rhodesiense than T. b. gambiense. Clinical manifestations generally appear within 1–3 weeks of the infective bite for T. b. rhodesiense and months to years for T. b. gambiense. | African trypanosomiasis is a human tropical parasitic disease usually caused by a protozoan hemoflagellates belonging to the complex Trypanosoma brucei. Infection is usually transmitted via the tsetse fly bite to the human host. A trypanosomal chancre develops on the site of inoculation. This is followed by a hemolymphatic stage with symptoms that include fever, lymphadenopathy, and pruritus. In the meningoencephalitic stage, invasion of the central nervous system can cause headaches, somnolence, abnormal behavior, and lead to loss of consciousness and coma. The course of infection is much more acute with T. b. rhodesiense than T. b. gambiense. Clinical manifestations generally appear within 1–3 weeks of the infective bite for T. b. rhodesiense and months to years for T. b. gambiense. | ||
==Causes== | ==Causes== | ||
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-In-Chief: Pilar Almonacid ; Aditya Ganti M.B.B.S. [2]
Overview
Sleeping sickness or African trypanosomiasis is a parasitic disease in people and animals, caused by protozoa of genus Trypanosoma and transmitted by the tsetse fly. The disease is endemic in certain regions of Sub-Saharan Africa, covering about 36 countries and 60 million people. The clinical course of human African trypanosomiasis has two stages. In the first stage, the parasite is found in the peripheral circulation, but it has not yet invaded the central nervous system. Once the parasite crosses the blood-brain barrier and infects the central nervous system, the disease enters the second stage. The subspecies that cause African trypanosomiasis have different rates of disease progression, and the clinical features depend on which form of the parasite (T. b. rhodesiense or T. b. gambiense) is causing the infection. However, infection with either form will eventually lead to coma and death if not treated.
Historical Perspective
African trypanosomiasis has been present in Africa for thousands of years. The causative agent and vector were identified in 1903 by David Bruce, and the differentiation between the subspecies of the protozoa made in 1910. [1]
Classification
African trypanosomiasis can be classified based upon the pathogen and geographic location into two types East African trypanosomiasis and West African trypanosomiasis.[2]
Pathophysiology
African trypanosomiasis is a human tropical parasitic disease usually caused by a protozoan hemoflagellates belonging to the complex Trypanosoma brucei. Infection is usually transmitted via the tsetse fly bite to the human host. A trypanosomal chancre develops on the site of inoculation. This is followed by a hemolymphatic stage with symptoms that include fever, lymphadenopathy, and pruritus. In the meningoencephalitic stage, invasion of the central nervous system can cause headaches, somnolence, abnormal behavior, and lead to loss of consciousness and coma. The course of infection is much more acute with T. b. rhodesiense than T. b. gambiense. Clinical manifestations generally appear within 1–3 weeks of the infective bite for T. b. rhodesiense and months to years for T. b. gambiense.
Causes
African trypanosomiasis is a human tropical parasitic disease usually caused by a protozoan hemoflagellates belonging to the complex Trypanosoma brucei. Two subspecies that are morphologically indistinguishable cause distinct disease patterns in humans: T. b. gambiense causes West African sleeping sickness and T. b. rhodesiense causes East African sleeping sickness.
Differentiating African trypanosomiasis from other diseases
The hemo-lymphatic stage of African trympnosomiasis presents with a rash, fever and anemia and must be differentiated with other diseases such as brucellosis, typhoid fever, malaria, tuberculosis, lymphoma, Dengue, Leptospirosis. Most prominent symptom in neurological stage of African trypanosomiasis is mental status changes and sleep disturbances, differential diagnoses in CNS TB, meningitis, and HIV-related opportunistic infections, including cryptococcal meningitis.[3][4][5][6]
Epidemiology and Demographics
Currently, it is estimated that the annual prevalance of African trypanosomiasis is less than 20,000. In 2014, 3,796 sleeping sickness cases were reported to the World Health Organization; T. b. gambiense accounted for >98% of cases. There is no age predominance for African trypanosomiasis disease.[7][8][9][10]
Risk Factors
Risk factors for African trypanosomiasis include residence in Central or South America, living in old houses with either mud and sticks wall constructions or straw roofs, ingestion of contaminated water, or receiving blood transfusions/organ donation from individuals in regions with high endemicity. Risk of infection increases with the number of times a person is bitten by the tsetse fly. Neonatal risk is highest among those who breastfeed from bleeding / cracked nipples of infected mothers and those who are delivered from seropositive mothers with active disease.
Natural History, Complications and Prognosis
If left untreated, the patient will develop symptoms of progressive mental deterioration, which is irreversible and eventually lead to death. Common complications that can develop as a result of African trypanosomiasis include anemia, aspiration pneumonia, meningoencephalitis, seizures, coma, perinatal death or abortion (congenital infection). The prognosis of African trypanosomiasis is good with treatment. Without treatment, the mortality rate of African sleeping sickness is close to 100%.[11][12]
Laboratory Findings
The diagnosis of African trypanosomiasis rests upon demonstrating trypanosomes by microscopic examination of chancre fluid, lymph node aspirates,blood,bone marrow, or, in the late stages of infection, cerebrospinal fluid.
Treatment
Medical Therapy
Medical treatment of African trypanosomiasis should begin as soon as possible and is based on the infected person’s symptoms and laboratory results. Medications are the mainstay of treatment for African trypanosomiasis. Pentamidine isethionate and suramin are the drugs of choice to treat the hemolymphatic stage of West and East African Trypanosomiasis, respectively. Melarsoprol is the drug of choice for late disease with central nervous system involvement (infections by T.b. gambiense or T. b. rhodiense). Hospitalization is necessary for the second stage of the disease. Periodic follow-up exams that include a spinal tap are required for 2 years. If a person fails to receive medical treatment for African trypanosomiasis, death will occur within several weeks to months.
Surgery
Surgical intervention is not recommended for the management of African trypanosomiasis.
Prevention
Prevention and control focus on the eradication of the parasitic host, the tsetse fly. Methods of primary prevention of African trypanosomiasis include use of insecticides to control the vector, use of new construction compounds in building walls and roofs, and organ/blood testing prior to donation. Regular active surveillance, involving case detection and treatment, in addition to tsetse fly control, is the backbone of the strategy for control of sleeping sickness
References
- ↑ Template:Cite paper
- ↑ Picozzi K, Fèvre EM, Odiit M, Carrington M, Eisler MC, Maudlin I, Welburn SC (2005). "Sleeping sickness in Uganda: a thin line between two fatal diseases". BMJ. 331 (7527): 1238–41. doi:10.1136/bmj.331.7527.1238. PMC 1289320. PMID 16308383.
- ↑ Pappas G, Akritidis N, Bosilkovski M, Tsianos E (2005). "Brucellosis". N Engl J Med. 352 (22): 2325–36. doi:10.1056/NEJMra050570. PMID 15930423.
- ↑ Brucellosis "Dennis Kasper, Anthony Fauci, Stephen Hauser, Dan Longo, J. Larry Jameson, Joseph Loscalzo"Harrison's Principles of Internal Medicine, 19e Accessed on January,2017
- ↑ Young EJ (1995). "Brucellosis: current epidemiology, diagnosis, and management". Curr Clin Top Infect Dis. 15: 115–28. PMID 7546364.
- ↑ Enfermedades infecciosas: Brucelosis -Diagnóstico de Brucelosis,Guia para el Equipo de Salud. Ministerio de Salud-Argentina. http://www.msal.gob.ar/images/stories/bes/graficos/0000000304cnt-guia-medica-brucelosis.pdf. Accessed on February 2, 2016
- ↑ Fèvre EM, Picozzi K, Jannin J, Welburn SC, Maudlin I (2006). "Human African trypanosomiasis: Epidemiology and control". Adv. Parasitol. 61: 167–221. doi:10.1016/S0065-308X(05)61005-6. PMID 16735165.
- ↑ Franco JR, Simarro PP, Diarra A, Jannin JG (2014). "Epidemiology of human African trypanosomiasis". Clin Epidemiol. 6: 257–75. doi:10.2147/CLEP.S39728. PMC 4130665. PMID 25125985.
- ↑ "Trypanosomiasis, African (Sleeping Sickness) - Chapter 3 - 2018 Yellow Book | Travelers' Health | CDC".
- ↑ "WHO | The current situation".
- ↑ Blum J, Schmid C, Burri C (2006). "Clinical aspects of 2541 patients with second stage human African trypanosomiasis". Acta Trop. 97 (1): 55–64. doi:10.1016/j.actatropica.2005.08.001. PMID 16157286.
- ↑ Levine IM, Jossmann PB, DeAngelis V (1977). "Liorseal, a new muscle relaxant in the treatment of spasticity--a double-blind quantitative evaluation". Dis Nerv Syst. 38 (12): 1011–5. PMID 338269.