Human African Trypanosomiasis in Suburban and Urban Areas: A Potential Challenge in the Fight Against the Disease
Received Date: Nov 21, 2011 / Accepted Date: Jan 20, 2012 / Published Date: Feb 09, 2012
Sub-Saharan countries are facing a demographic growth of 3% per year. That increase of the population in number, associated with climate changes, has deeply modified environmental landscape and affected biodiversity. The distribution of tsetse flies or Glossina, vector of sleeping sickness, has been considerably modified over time. Species of morsitans group (Glossina subgenus) had disappeared from some areas, while those of palpalis group (Nemorhina subgenus) developed and adaptation in Human habitats with peridomestic behaviors. The great capacity of these species to adapt in suburban and urban areas as soon as microclimatic conditions and host availability are met has brought up a new epidemiological context of the disease: suburban and urban foci. We are reviewing that epidemiological feature in order to draw attention to that particular aspect which may impede the progress of disease elimination in sight in many T. b. gambiense sleeping sickness foci.
Keywords: Vector-borne disease; Human African trypanosomiasis; Trypanosoma brucei; Demographic growth; Urbanization; Glossina foci
Sleeping sickness or human African trypanosomiasis (HAT) is a vector-borne parasitic disease that is fatal if left untreated. It is caused by a single-celled protozoa belonging to the Trypanosoma genus. Parasites are transmitted to humans by the bite of a tsetse fly (Glossina Wiedeman, 1830 genus) that has acquired the infection from human beings or from animals harboring the human pathogenic parasites. The disease takes two forms, depending on the parasite involved: the chronic form due to Trypanosoma brucei gambiense Dutton, 1902 found in west and central Africa which represents more than 97% of reported cases and the acute form due to Trypanosoma brucei rhodesiense Stephens & Fanthams, 1910 found in eastern and southern Africa . Sleeping sickness is restricted to sub-Saharan Africa, in the range of the tsetse vector. Tsetse flies are specifically distributed within their area: they are closely related to vegetation which forms a screen from solar radiations and wind and which is itself dependent on the presence of surface or underground water, that increases the humidity of both atmosphere and soils . In West and Central Africa, the riverine forest species, belonging to the Glossina (Nemorhina) Robineau-Desvoidy, 1830, subgenus are the more important vectors of the disease. The distribution of the parasites and consequently the disease within the vector range is focal. Thus, sleeping sickness is a public health problem where the vector, the parasite (and its reservoir hosts) and humans co-exist.
Current epidemiological situation
The epidemiology of sleeping sickness is characterized by its occurrence in foci: a focus defined as “a zone of transmission to which a geographical name is given” . The impact of sleeping sickness in terms of public health lies not in the annual incidence, but in its potential for the development of explosive epidemics causing thousands of deaths. If incidence alone is considered, the disease appears as a minor health problem compared with other parasitic diseases like malaria and helminthic infections . Distribution of HAT is very heterogeneous. The disease develops in areas whose size can range from a village to an entire region. Within a given area, the intensity of the disease can vary from one village to the next. In the 1990s, estimates (both forms combined) for HAT indicated that 60 million people were at risk in approximately 250 distinct foci of 36 sub-Saharan countries . Prevalence of 50% had been reported in some villages in the Democratic Republic of Congo, Angola and Southern Sudan. Sleeping sickness was considered as the first or second greatest cause of mortality in those communities. Thanks to many control measures such as systematic patient screening, treatment and follow-up established in western and central Africa for the T. b. gambiense form and the animal reservoir and vector control implemented in eastern and southern Africa for the T. b. rhodesiense form, the number of new cases reported throughout the continent had substantially reduced: less than 10,000 new cases reported in 2009 for the first time in 50 years ; which represents a decrease of 63% since 2000 .
The T. b. gambiense form of the disease has in several foci already reached a prevalence threshold compatible with the concept ‘‘eliminated as a public health problem’’ . In other foci, the disease remains a public health issue due to poor accessibility or security constraints . The occurrence of sleeping sickness is related to the presence of the cyclical vector. But, for reasons that are so far unexplained, there are many regions where tsetse flies are found but sleeping sickness is not [8,2]. Glossina species are known to survive only in very specific types of habitat, where the density of canopy and underwood determines suitable environmental conditions (temperature, humidity, luminosity), easiness of flight, as well as the presence of animals which are tsetse fly feeding hosts . Due to such peculiar environmental conditions, tsetse flies are mainly found in remote areas and therefore, sleeping sickness is considered as a disease affecting rural areas; a disease of poor, marginalized and rural populations who depend on their land and labor for a livelihood . It is one of the seventeen Neglected Tropical diseases . The transmission of the T. b. gambiense form to humans is principally related to close contact with the fly. Species of the palpalis group (Nemorhina subgenus), main vectors of the disease, have great capacity for adaptation to peridomestic habitats. Thus, human populations and, to a certain extent, domestic animals are important factors affecting the distribution of these vectors . They are found widespread in all components of the ecosystem in infested areas, including forest, “interstitial savannas”, coffee and cocoa plantations, tracks and villages . This wide and close distribution of the vector to human beings (species of palpalis group are known to easily colonized anthropics habitats), combined with massive immigration of populations (potential human reservoir of parasites) from rural areas to towns has brought up a new epidemiological feature of the disease: suburban and urban sleeping sickness foci.
Urbanization and sleeping sickness
Urbanization is a fairly recent phenomenon in Africa. There is no global standard for the classification of urban environments, as the definition of what constitutes an urban area varies among countries and in some cases it even varies over time within a single country . Some countries define their urban population as those people living within certain administrative boundaries, such as administrative centers or municipality councils. Other countries prefer to classify their urban population using population size or population density as the primary consideration and economic function as the second. Thus, places that are classified as urban in one country may be classified as rural in another. For example, In Angola, all localities with 2000 inhabitants or more are considered urban, while in Benin only localities with 10000 inhabitants or more are classified as urban and communities fewer than 10000 inhabitants are classified as rural . This criterion and others such as non-agricultural activity of at least 75 percent of the population  are not considered in defining urban or suburban sleeping sickness foci. Besides, the geographical extent of cities changes significantly over time due to many factors in relation to human growth such that an urban HAT focus described in the 1960s may be considered as a rural focus in the 2000s.
Urban sleeping sickness focus is an old concept. It was firstly described in 1960s, both in the savanna and forest zones. The savanna HAT urban focus described was in Bamako, Mali where the transmission and the manifestation of the disease in the town were favored by a rural to urban migration of populations (human reservoir of parasite) that followed independence days and to an existence of suitable environmental conditions for survival of tsetse flies in the vicinity of the town [16,17]. In Brazzaville, the forest HAT urban focus described [18,19], that the reason of the manifestation of the disease in the town was not a direct consequence of a rural to urban migration of populations. Brazzaville is an old sleeping sickness focus. From 1906 to 1908, all HAT cases diagnosed in the hinterland (known as “Afrique Equatoriale française” which at that time joined together three countries: Gabon, Congo and Central African Republic) were brought to Brazzaville, the capital for treatment . That operation favored the endemicity of the disease in an area highly infested with tsetse flies. During that period, road construction, housing estate and buildings pushed tsetse resting sites at the periphery of the town, around the Djoue stream, tributary to the Congo River and the disease in 1970s was mainly endemic only in suburbs. But in the zoological park, an area kept in its natural conditions downtown Brazzaville, Glossina were still present due to suitable environmental conditions and feeding hosts (primates, suids, bovids, reptiles, etc. ) tamed in the area. Brazzaville was, therefore known as a suburban and urban HAT focus . In the course of time, demographic concentration and human activities destabilized the ecosystem balance and, some years later, it was pointed out that a vector control activity was progressively achieving itself in downtown Brazzaville, due to urbanization and market gardening along streams and ravines [22,23]. In 1992, it was even observed that the southern limit of tsetse distribution around Brazzaville was then far from the Djoue stream, with a progressive replacement of G. fuscipes quanzensis by G. palpalis palpalis . Meanwhile, the zoological park was hardly under control despite vector control activities put in place  up to the end of 1990, when animals tamed in the zoo were killed because of a civil unrest in Brazzaville. The absence of blood meals for tsetse compromised their survival in the area and, ten years later, an entomological survey suggested the Glossina disappearance from the zoo . Nowadays, Brazzaville suburban and urban focus no longer exists. Nevertheless, as the Mbamou Island situated in the Stanley Pool, upstream from Brazzaville is still a tsetse infested area (Kohagne, personal communication) and there is an intense population’s movements between active sleeping sickness foci (located in the hinterland) and Brazzaville, one could consider that Brazzaville human population is still at risk of HAT. More recently, Glossina resting sites were also described in suburbs of many others cities, such as Bangui in the Central African Republic , Daloa, Sinfra and Bonon in Côte d’Ivoire [27-30], Kinshasa in the Democratic Republic of Congo [31-33] and Dubréka, Boffa in Guinea . Many of these areas are historical sleeping sickness foci where, currently, population’s settlement has pushed tsetse flies to the periphery of the town. Although these foci exhibited the same epidemiological feature, suburban or urban foci, modalities of the disease transmission varied according to human behavior and to local environment. In Côte d’Ivoire, urban foci are mainly observed in the Center-West of the country, in areas where intensive coffee and cocoa cultivation has favored expansion of towns, due to a higher concentration of populations. Disease transmission does not occur in the city-centre; people live in town but get infected during their rural activities in tsetse infested areas located in the vicinity. Such foci are called “rural foci with urban manifestation” . In suburbs of Kinshasa town, comprising a hardly altered ecosystem around a builtup area, there exists natural human-fly-human transmission cycle since T. b. gambiense has been identified from infected flies . Kinshasa is a town located along the Congo River with many tributary streams: Djili, N’Sele, Lukaya, Lukunga, Mikonga, Kalamu and Makélélé. That township shelters about 10,000,000 inhabitants in three different ecological parts: an urban area (city-centre), a suburban area and a rural area. Suburban and rural areas harbor 80% to 90% of the total of inhabitants who, though being civil servants, are regularly involved in rural activities (farming, fishing, etc. ) because of economic crisis . Environmental conditions around the Congo River and its tributary streams are suitable not only for human activities, but also for tsetse flies and during the discharge of their duties; people are exposed to bite of the flies and at risk of infection with sleeping sickness. Contrary to the suburban focus of Brazzaville where demographic pressure has annihilated tsetse resting sites and transmission of sleeping sickness, demographic concentration in Kinshasa seems to lesser effect on the endemicity of the disease in the outskirts of the town. In Libreville, Gabon, the suburban HAT focus exhibits a peculiar epidemiological characteristic. Libreville is a town opened to the Atlantic Ocean where coastal vegetation is made essentially by swamp mangrove, suitable for tsetse flies. The Gabon estuary is known to be an overflowing tsetse infested area [35,36] and the extension of the town has brought closer tsetse resting sites to urban population. In the past, that area was frequented only by fisher-men (potential human reservoir of parasites) who are incriminated to spread the disease in the coastal area of Gabon [36,37] and who have probably, favored the outbreak of the disease in that suburban location. Actually, the suburban area of Libreville town is used by all citizens for various activities including fishing, trade and tourism. The consequence of the several and regular frequentation of populations in tsetse infested area neighborhood Libreville is that, sleeping sickness is, henceforth, passively diagnosed in populations from all strata of society and from all origins, even in Europeans [38,39]. So far, only certain particular strata of society were involved in suburban or urban sleeping sickness transmission. The suburban HAT focus of Libreville is revealing other epidemiological feature.
Urbanization occurs through three distinct channels: the rural to urban migration, the growth of the existing urban population and the reclassification of rural areas into urban or otherwise . In many Sub-Saharan Africa countries, urbanization is the consequence of a rural to urban migration of populations that followed the independence period. The increase of human settlements leading to a population explosion amplified human activities and profound pressure was perceptible on the land, wildlife and forest resources. This has resulted in an overall reduction in natural tsetse habitats and wildlife hosts of several Glossina spp . The corresponding alteration in the pattern of tsetse distribution was that tsetse species were now seeking more environmental conducive habitats with abundant hosts. Human habitats are fast becoming tsetse conducive, particularly for the riverine group species which exhibit peridomestic behaviors . Urban environmental changes reduced the extent of potential tsetse biotopes, but the pattern of urban land use leads to an increase in human population density and favors man-fly contact which is an important factor in sleeping sickness transmission. Thus, urbanization did not bring about cessation of HAT transmission; rather it did result in the concentration of tsetse in the town outskirts, where environmental conditions remain conducive to survival of the flies and for manvector contact enough for the disease transmission. In the course of time, urbanization extends through the growth of the existing urban population. The effects on land use (housing estate, road construction, etc.) in conjunction with local (or global) changes in climatic parameters become pronounced and environmental degradation contributes to tsetse disappearance and consequently, disappearance of existing suburban sleeping sickness focus, such as Bamako and Brazzaville. It is known that high population growth could eliminate tsetse flies from large areas, irrespective of control activities . That phenomenon has been observed in some quarters of the suburban area of Kinshasa town, where tsetse flies disappeared without any deliberate intervention against the vector, but primarily because of the population growth and its impact on the environment . The assumption is that human population density is correlated with the area of tsetse habitat cleared for cultivation or housing estate . However, the risk of trypanosome transmission is not absolutely correlated to vector density, but depends also on a number of contextual factors including human mobility . In many sub-Saharan countries, urbanization is rarely defined upon the basis of non-agricultural activities. People living in town, civil servants, traders or self-employees are for the most part involved in agricultural activities (cocoa, coffee, palm tree, etc.) practiced in appropriate areas located either in the neighborhood or far from the town. In sleeping sickness endemic areas, the constant presence of populations in tsetse infected areas acts in favor of an intense contact with flies and urban populations are exposed to the disease in the same way as those living in the rural tsetse infested areas. The existence of the disease in the urban area is sometimes a consequence of an intense relationship between rural and urban areas . Knowledge about local epidemiology situation of HAT is necessary for the success of a control program. In many T. b. gambiense foci, the main strategy put in place is active mass screening (by mobile teams examining populations at risk, village by village) and treatment of all cases detected. This approach is addressing the occurrence of the disease mainly in rural areas, at the furthest extremities of the formal health system, where it is difficult for patients to access health care particularly for those in the second stage of the disease and for control campaigns to have an effective outreach [46,47]. With the spread of HAT in urban areas, one could assume that sleeping sickness control by active case-detection strategy would be reinforced by an efficient passive case-detection since affected individuals would easily come to the health centers or hospitals for examination. But, clinical signs of sleeping sickness are generally unspecific and their frequency varies between individuals and between disease foci . Most patients in early stage will be missed and their presence within the populations will contribute to the spread of the disease. In urban foci where the disease transmission is related to a well implemented agricultural system, exposed populations (labor) should be screened and examined in their job place for more efficiency. Indeed, large-scale control campaigns targeting only the human reservoir can locally eliminate transmission of sleeping sickness . In urban areas where exposed populations are not well defined because of that, transmission is more related to the regular presence of individuals in tsetse infested area than to a particular activity, it would be really necessary to think about an integrated approach that would take in account all elements of the transmission cycle. In some HAT endemics countries, medical profession is not always aware of extend of the disease; thus, significance should be given to the consciousnessraising of the potential incidence of HAT in urban local population. In contrast of what previously expected about a probable extinction of tsetse flies because of a population growth [42,44], urbanization has brought up an epidemiological feature which may constituted a new challenge in the fight against trypanosomiasis. Some analysis has shown that riverine species are little affected or not at all by human population growth and are thus likely to remain extant indefinitely . Indeed, in areas both infected by savanna (morsitans group) and riverine species, the number and the distribution of species of morsitans group decreased in the course of time, while those of palpalis group are less affected [50,51]. Moreover, beyond their peridomestic behavior, species of palpalis group exhibit an ability to adapt in big urban centers as soon as microclimatic conditions and host availability are met, with a possibility to transmit trypanosomosis  and even a biting nuisance to humans in their houses . Several domestic animals such as pigs, goats and sheep are known to harbor T. b. gambiense [54-56]. The role of animal reservoir in the maintain and the resurgence of sleeping sickness is not well defined. However, as domestic animals close to human beings can harbor and even amplified human’s trypanosomes, there is an urgent need to think about a new strategy that will interrupt the progression of the disease in urban areas
Authors are grateful to Pr Mamman Mohammed and Dr Peter Dede of the Nigerian Institute for Trypanosomiasis Research (NITR) for the very useful criticisms of the manuscript.
- Simarro PP, Cecchi G, Paone M, Franco JR, Diarra A, et al. (2010) The Atlas of human African trypanosomiasis: a contribution to global mapping of neglected tropical diseases. Int J Health Geogr 9: 57.
- Solano P, Bouyer J, Itard J, Cuisance D (2010) The cyclical vectors of trypanosomosis. Infectious and Parasitic Diseases of Livestock 13: 155-183.
- (1998) Control and surveillance of African trypanosomiasis. Report of a WHO Expert Committee. World Health Organ Tech Rep Ser 881: 1-114.
- Cattand P, Jannin J, Lucas P (2001) Sleeping sickness surveillance: an essential step towards elimination. Trop Med Int Health 6: 348-361.
- World Health Organization (2010) Human African trypanosomiasis: number of new cases drops to historically low level in 50 years.
- Simarro PP, Diarra A, Ruiz Postigo JA, Franco JR, Jannin JG (2011) The human African trypanosomiasis control and surveillance programme of the World Health Organization 2000-2009: the way forward. PLoS Negl Trop Dis 5: e1007.
- Chappuis F, Lima MA, Flevaud L, Ritmeijer K (2010) Human African trypanosomiasis in areas without surveillance. Emerg Infect Dis 16: 354-356.
- FORD J (1963) The distribution of the vectors of African pathogenic trypanosomes. Bull World Health Organ 28: 653-669.
- OMS, Bureau Régional de l’Afrique (2005) Lutte contre la trypanosomiase humaine africaine : une stratégie pour la région africaine. Rapport du Directeur régional. 184 Comité Régional de l’Afrique, Cinquante-cinquième session, Maputo, Mozambique, AFR/RC55/11.
- World Health Organization (2007) Global plan to combat neglected tropical diseases 2008-2015.
- Leak SGA (1999) Tsetse biology and ecology: Their role in the epidemiology and control of trypanosomiasis. CABI publishing.
- Challier A, Gouteux JP (1980) Ecology and epidemiology importance of Glossina palpalis in the Ivory Coast forest zone. Insect Science and its Application 1: 77-83.
- Cohen B (2006) Urbanization in developing countries: Current trends, future projections, and key challenges for sustainability. Technology in Society 28: 63-80.
- United Nations (2002) World urbanization prospects: the 2001 revision. New York.
- Van de Poel E (2009) Urbanization, Health and Inequality in the Developing World. Thesis to obtain the degree of Doctor from the Erasmus University Rotterdam, The Netherlands.
- Challier A (1962) Campagne de Lutte contre Glossina palpalis gambiensis Vanderplank dans le foyer de Bamako (République du Mali). 9ème réunion du Comité Scientifique International de Recherches sur les Trypanosomiases (CSIRT), Conakry.
- Ricossé JH, Challier A, Le Mao G, Albert JP, Legait JP (1973) L’épidémiologie actuelle de la trypanosomiase humaine africaine et les problèmes qu’elle pose. Médecine d‘Afrique Noire 20: 291-299.
- Taufflieb R (1965) Les glossines de l’agglomération brazzavilloise. Brazzaville, ORSTOM,
- Molouba R, Djai-Moulenvo J, Coulm J (1976) Situation épidémiologique en République populaire du Congo, de 1963 à 1975 : bilan d’activités du service d’épidémiologie et des grandes endémies. SEGE.
- Martin G, Leboeuf PNA, Roubaud E (1909) Rapport de la mission d’études de la maladie du sommeil au Congo-Français, 1906-1908. Masson, Paris.
- Frézil JL, Adam JP, LePont F (1972) Les glossines de l’agglomération brazzavilloise : situation actuelle (1970-1972). Brazzaville, ORSTOM.
- Gouteux JP, Nkouka E, Noireau F, Frézil JL, Sinda D (1986) The tsetse-flies of Brazzaville I. Repartition and importance of the breeding and resting sites. Revue d’Elevage et de Médecine Vétérinaire dans les Pays Tropicaux 39: 355–362.
- Noireau F, Toudic A, Gouteux JP, Bissadidi N, Frézil JL, Duteurtre JP (1987) Les glossines de l’agglomération brazzavilloise 3. Rôle vecteur dans les trypanosomoses animales et humaines. Revue d’Elevage et de Médecine Vétérinaire dans les Pays Tropicaux 40: 67-69.
- Gouteux JP (1992) Un cas d’exclusion géographique chez les glossines: l’avancée de Glossina palpalis palpalis vers Brazzaville (Congo) au détriment de G. fuscipes quanzensis. Insect Science and its Application 1: 59-67.
- Tongué LK, Diabakana PM, Bitsindou P, Louis FJ (2009) Have tsetse flies disappeared from Brazzaville town? Pan Afr Med J 3: 3.
- D'Amico F, Moussa A, Sarda J, Gouteux JP (1992) [Distribution and importance of sites of Glossina fuscipes fuscipes Newstead 1910 in the agglomeration of Bangui (Central Africal Republic)]. Bull Soc Pathol Exot 85: 64-68.
- Fournet F, Traoré S, Hervouët JP (1999) Effects of urbanization on transmission of human African trypanosomiasis in a suburban relict forest area of Daloa, Côte d'Ivoire. Trans R Soc Trop Med Hyg 93: 130-132.
- Laveissière C, Garcia A, Sané B (2003) Lutte contre la Maladie du Sommeil et Soins de Santé Primaires. Institut de Recherche pour le Développement Paris, France.
- Courtin F, Dupont S, Zeze DG, Jamonneau V, Sané B, et al. (2005) Human African trypanosomiasis: urban transmission in the focus of Bonon (Côte d'Ivoire). Trop Med Int Health 10: 340-346.
- Courtin F, Jamonneau V, Oké E, Coulibaly B, Oswald Y, et al. (2005) Towards understanding the presence/absence of Human African Trypanosomosis in a focus of Côte d'Ivoire: a spatial analysis of the pathogenic system. Int J Health Geogr 4: 27.
- Louis FJ, Bilenge CM, Simarro PP, Meso VK, Lucas P, et al. (2003) Human African trypanosomiasis in an urban area: an emerging problem?. Bull Soc Pathol Exot 96: 205-208.
- Ebeja AK, Lutumba P, Molisho D, Kegels G, Miaka mia Bilenge C, et al. (2003) Sleeping sickness in the region of the town of Kinshasa: a retrospective analysis during the surveillance period 1996-2000. Trop Med Int Health 8: 949-955.
- Simo G, Mansinsa Diabakana P, Kande Betu Ku Mesu V, Manzambi EZ, Ollivier G, et al. (2006) Human African trypanosomiasis transmission, Kinshasa, Democratic Republic of Congo. Emerg Infect Dis 12: 1968-1970.
- Camara M, Kaba D, KagbaDouno M, Sanon JR, Ouendeno FF, et al. (2005) Human African trypanosomiasis in the mangrove forest in Guinea: epidemiological and clinical features in two adjacent outbreak areas. Med Trop (Mars) 65: 155-161.
- Maillot L (1953) Carte de la distribution probable des sous-espèces et variétés de Glossina palpalis. échelle 1/28 000 000. ORSTOM, service cartographie, Paris.
- Kohagne Tongué L, Mengue M’eyi P, Mimpfoundi R, Louis JF (2010) Entomological patterns in the human African trypanosomiasis focus of Komo Mondah, Gabon. Afr Health Sci 10: 341-348.
- Kohagne Tongué L, Mengue M’eyi P, Gounoue Kamkuimo R, Kaba D, Louis FJ, et al. (2011) Transmission of human African trypanosomiasis in the Komo-Mondah focus, Gabon. Pan Afr Med J 8: 36.
- Hope-Rapp E, Moussa Coulibaly O, Klement E, Danis M, Bricaire F, et al. (2009) [Double trypanosomal chancre revealing West African trypanosomiasis in a Frenchman living in Gabon]. Ann Dermatol Venereol 136: 341-345.
- Gautret P, Clerinx J, Caumes E, Simon F, Jensenius M, et al. (2009) Imported human African trypanosomiasis in Europe, 2005-2009. Euro Surveill 14.
- Swynnerton CFM (1936) The tsetse flies of East Africa. A first study of their ecology, with a view to their control. Transactions Royal Entomology Society, London.
- Laveissière C, Hervouët JP, Couret D (1986) Localisation et fréquence du contact homme/glossine en secteur forestier de Côte d’ivoire 2. Le facteur humain et la transmission de la trypanosomiase. Cahier ORSTOM, série Entomologie et Parasitologie 24: 45-57.
- Jordan AM (1986) Trypanosomiasis Control and African Rural Development. Longman, London, UK.
- Mansinsa DP, Kande BKV, Van-Der Veken W (2009) Effets de la pression démographique sur la répartition des glossines et l’évolution de la trypanosomiase humaine africaine en milieu urbain et périurbain de la ville province de Kinshasa, République Démocratique du Congo. Sciences et Médecine d’Afrique 2009 1: 27-31.
- McDermott JJ, Kristianson PM, Kruska RL, Reid RS, Robinson TP, et al. (2001) Effects of Climate, Human Population and Socio-Economic Changes on Tsetse-Transmitted Trypanosomiasis to 2050. In: Black SJ SJ, Seed JR, editors. The African Trypanosomes. Kluwer Academic Publishers, Boston.
- Laveissière C, Grébaut P, Herder S, Penchenier L (2000) Les glossines vectrices de la trypanosomiase humaine africaine. IRD/OCEAC Yaoundé.
- Odiit M, Shaw A, Welburn SC, Fèvre EM, Coleman PG, et al. (2004) Assessing the patterns of health-seeking behaviour and awareness among sleeping-sickness patients in eastern Uganda. Ann Trop Med Parasitol 98: 339-348.
- Gouteux JP, Bansimba P, Noireau F, Frezil JL (1987) [Cost of the individual treatment of Trypanosoma brucei gambiense trypanosomiasis in a focus of infection in Niari (Congo)]. Med Trop (Mars) 47: 61-63.
- Simarro PP, Franco JR, Ndongo P, Nguema E, Louis FJ, et al. (2006) The elimination of Trypanosoma brucei gambiense sleeping sickness in the focus of Luba, Bioko Island, Equatorial Guinea. Trop Med Int Health 11: 636-646.
- Reid SR, Kruska RL, Deichmann U, Thornton PK, LEAK S (2000) Human population growth and the extinction of the tsetse fly. Agriculture Ecosystem and Environment 77: 227-236.
- Rayaissé JB, Courtin F, Akoundjin M, César J, Solano P (2009) Influence of anthropisation on local vegetation and tsetse abundance in southern Burkina Faso. Parasite 16: 21-28.
- Rouamba J, Jamonneau V, Sidibé I, Solano P, Courtin F (2009) Impact de la dynamique de peuplement sur la distribution des glossines et des trypanosomoses dans la boucle du Mouhoun (Burkina Faso). Parasite 16: 11- 19.
- Keck N, Herder S, Kaba D, Solano P, Gomez J, et al. (2009) Epidemiological study of canine trypanosomosis in an urban area of Ivory Coast. Parasite 16: 305-308.
- Dede PM, Halid GA, Omoogun NR, Uzoigwe CI, Njoku AD, et al. (2005) Current Tsetse and Trypanosomosis Situation on Jos Plateau, Nigeria. Epizootiological Factors that May Enhance Disease Transmission and Spread. Revue d’Elevage et de Médecine Vétérinaire dans les Pays Tropicaux 58: 31-35.
- Njitchouang GR, Njiokou F, Nana Djeunga HC, Moundipa Fewou P, et al. (2010). Analysis of the domestic animal reservoir at a microgeographical scale, the Fontem sleeping sickness focus (South-West Cameroon) Journal of Cell and Animal Biology 4: 73-80.
- Njiokou F, Nimpaye H, Simo G, Njitchouang GR, Asonganyi T, et al. (2010) Domestic animals as potential reservoir hosts of Trypanosoma brucei gambiense in sleeping sickness foci in Cameroon. Parasite 17: 61-66.
- Cordon-Obras C, Berzosa P, Ndong-Mabale N, Bobuakasi L, Buatiche JN, et al. (2009) Trypanosoma brucei gambiense in domestic livestock of Kogo and Mbini foci (Equatorial Guinea). Trop Med Int Health 14: 535-541.
Citation: Tongue LK, Mavoungou JF, Kamkumo RG, Kaba D, Fako Hendji GC, et al. (2012) Human African Trypanosomiasis in Suburban and Urban Areas: A Potential Challenge in the Fight Against the Disease. J Clinic Experiment Pathol S3:002. Doi: 10.4172/2161-0681.S3-002
Copyright: © 2012 Tongue LK, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Select your language of interest to view the total content in your interested language
Share This Article
- Total views: 17398
- [From(publication date): 0-2012 - May 25, 2020]
- Breakdown by view type
- HTML page views: 13539
- PDF downloads: 3859