In vitro trypanocidal activity of antibodies to bacterially expressed Trypanosoma brucei tubulin

There are only four drugs for treating African trypanosomiasis, a devastating disease in sub-Saharan Africa. With slow discovery of better drugs, vaccination is viewed as the best method of control. We previously showed that antibodies to native Trypanosoma brucei brucei tubulin inhibit the growth of trypanosomes in culture. Here, we aimed to determine the effect of antibodies to bacterially expressed trypanosome tubulin on T. brucei brucei growth. T. brucei brucei alpha and beta tubulin genes were individually expressed in Escherichia coli under the tryptophan promoter. Monoclonal tubulin antibodies reacted specifically with the expressed tubulins with no cross-reaction with the opposite tubulin. Rabbits were immunized with 450micro g each of the concentrated recombinant tubulin, and production of antibodies assessed by ELISA and Western blotting. The effect of polyclonal antibodies on trypanosome growth was determined by culturing bloodstream T. brucei brucei in up to 25% of antisera. Low antisera dilutions [25%] from the immunized rabbits inhibited trypanosome growth. The most cytotoxic antisera were from one rabbit immunized with a mixture of both alpha and beta tubulins. However, the result was not reproduced in other rabbits and there was no apparent effect on growth at higher antisera dilutions. Antibodies to bacterially expressed trypanosome tubulin are not effective at killing cultured bloodstream trypanosomes

Photodynamic antimicrobial chemotherapy (PACT) for the treatment of malaria, leishmaniasis and trypanosomiasis

A photodynamic effect occurs when photosensitiser molecules absorb light and dissipate the absorbed energy by transferring it to biological acceptors (usually oxygen), generating an excess of reactive species that are able to force cells into death pathways. Several tropical diseases present physiopathological aspects that are accessible to the application of a photosensitiser and local illumination. In addition, disease may be transmitted through infected blood donations, and many of the aetiological agents associated with tropical diseases have been shown to be susceptible to the photodynamic approach. However, there has been no systematic investigation of the application of photoantimicrobial agents in the various presentations, whether to human disease or to the disinfection of blood products or even as photo-insecticides. We aim in this review to report the advances in the photoantimicrobial approach that are beneficial to the field of anti-parasite therapy and also have the potential to facilitate the development of low-cost/high-efficiency protocols for underserved populations.

Vaccination with epimastigotes of different strains of Trypanosoma rangeli protects mice against Trypanosoma cruzi infection

In our laboratory, we have developed a model of vaccination in mice with Trypanosoma rangeli, a non-pathogenic parasite that shares many antigens with Trypanosoma cruzi. The vaccinated mice were protected against infection with virulent T. cruzi. The goal of the present work was to study the protective activity of strains of T. rangeli of different origin, with the aim of analysing whether this protective capacity is a common feature of T. rangeli. BALB/c mice were vaccinated with live or fixed epimastigotes of two T. rangeli strains, Choachi and SC-58. Vaccinated (VM) and control mice (CM) were infected with virulent T. cruzi, Tulahuen strain. The results showed that the levels of parasitemia of VM, vaccinated with the two strains of T. rangeli were significantly lower than those developed in CM. The survival rate of VM was higher than that CM. Histological studies revealed many amastigote nests and severe inflammatory infiltrates in the heart and skeletal muscles of CM, whereas in the VM only moderate lymphomonocytic infiltrates were detected. Altogether, the results of the present work as well as previous studies show that the antigens involved in the protection induced by T. rangeli are expressed in different strains of this parasite. These findings could prove useful in vaccine preparation.

Human African Trypanosomiasis and challenges to its control in Urambo; Kasulu and Kibondo Districts; western Tanzania

A study was carried out to determine the prevalence and management of Human African Trypanosomiasis (HAT) in Urambo; Kasulu and Kibondo districts of western Tanzania. Parasitological surveys for trypanosome and other blood parasites were conducted in selected villages. Interviews with health workers were conducted to explore facility capacity to diagnose and manage HAT. Community knowledge on tsetse and availability of trypanocidal drugs was explored. Results showed that; although health facility records showed HAT is an important public health problem in the three districts; typanosomes were found in 0.6of the examined individuals in Urambo district only. Malaria parasites with a prevalence of 12.1; 19.7and 9.7; in Urambo; Kibondo and Kasulu; respectively were detected in blood samples from the same individuals examined for trypanosomes. There was poor capacity for most of the health facilities in the diagnosis; treatment and control of HAT. In both districts; communities were knowledgeable of the tsetse identity (82.4) and had experienced tsetse bites (94). The majority (91.4) of the community members knew that they were at risk of acquiring HAT. However; only 29of the respondents knew that anti-trypanocidal drugs were readily available free of charge from health care facilities. Late treatment seeking behaviour was common in Kasulu and Urambo districts. In conclusion; health facilities in western Tanzania are faced with problems of poor capacity to diagnose and manage HAT and that treatment seeking behaviour among the communities at risk is poor. Efforts should be made to strengthen the capacity of the health facility to handle HAT cases and health education to the population at risk

Trypanosoma evansi control and horse mortality in the Brazilian Pantanal

The impact of three treatment strategies for Trypanosoma evansi control on horse mortality in the Brazilian Pantanal based on four size categories of cattle ranches is explored. The region's 49,000 horses are indispensable to traditional extensive cattle ranching and T. evansi kills horses. About 13 percent of these horses would be lost, annually, due to T. evansi if no control were undertaken. One preventive and two curative treatment strategies are financially justifiable in the Pantanal. The best available technology for the treatment of T. evansi from a horse mortality perspective is the preventive strategy, which spares 6,462 horses, annually. The year-round cure spares 5,783 horses, and the seasonal cure saves 5,204 horses on a regional basis relative to no control strategy. Regardless of the strategy adopted, 39 percent of the costs or benefits fall to the largest ranches, while 18 percent fall to the smallest ranches

Situation de la trypanosomiase humaine africaine en Ouganda

Malgre une certaine politique du doute adpotee par la communaute scientifique internationale; l'Ouganda a su faire ses choix et se donner les moyens de ses ambitions. De cette determination resulte que ce pays est l'un des seuls a pouvoir presenter un programme coherent de prevention de la trypanosomiase humaine africaine. Cette action a ete rendue possible grace a l'atmosphere de la liberalisation politique; sans laquelle tout essai de participation communautaire est voue a l'echec

Doenca do sono em Angola : uma calamidade

As confrontacaoes armadas nas Provincias das zonas endemicas do Zaire; Uige; Bengo e Kuanza Norte destruiram e favoreceram o saque de todas as infraestruturas; equipamentos de campanha; de laboratorio e meios de transporte. O reinicio das actividades de Programa em todas as areas endemicas esta conditionado ao seu reequipamento. Logo no reinicio das actividades pretende-se : travar uma luta generlizada contra a doenca do sono em Angola; a faim de reduzir a morbi-mortalidade causada por esta doenca e montar uma infraestrutura compativel para a luta

La lutte contre la trypanosomiase humaine africaine au Cameroun : rapport 1990-1992

La situation de la lutte contre la trypanosomiase humaine africaine au Cameroun est tres preoccupante. Les cas observes sont sous-estimes. La couverture des foyers en pieges de lutte est tres faible. La recession economique a ralenti tous les efforts de relance de la lutte malgre la volonte de reduire l'incidence de la maladie dans les foyers. La reprise des activites est conditionnee par consequent par une mobilisation urgente des ressources financieres; humaines et logistiques

Trypanosomiase humaine africaine : L'analyse decisionnelle comme outil de coordination et de gestion des programmes de lutte

La prise en charge de la maladie sommeil souffre de quelques difficultes. En effet; cette maladie est speficiquement africaine; et plus specifiquement subsaharienne et rurale. Cette prise en charge necessite donc un niveau de competence et un niveau technique eleve. La trypanosomiase entre en competition avec les grandes pandemies; telles que le SIDA; le paludisme; la bilharziose et bien d'autres. Ces constatations montrent que le depart du controle de la maladie du sommeil se fait avec un handicap considerable. La reussite d'un tel combat exige alors de travailler en reseau; afin de creer un veritable circuit de l'information et de savoir-faire

Determination des zones a risque de trypanosomiase humaine; application au controle et a la lutte pour une valorisation des acquis scientifiques

Depuis des annees; on a demontre que le piegeage est la seule technique utilisable pour la lutte contre les glossines; en utilisant la force de travail des communautes rurales; sous la supervision d'une equipe restreinte. Mais malgre les efforts des entomologistes pour reduire les couts de la lutte antivectorielle; ceux-ci sont difficilement supportables pour des etats africains concernes par la trypanosomiase humaine africaine. Ce travail de lutte serait certainement efficace s'il etait base sur un systeme d'information geographique et la teledetection. Ces derniers permettent en effet de caracteriser precisement les principaux foyers endemiques; d'extrapoler les resultats a l'ensemble d'une zone biogeographique et de prevoir la localisation des futures zones a risques

Les equipes mobiles de l'an 2000

La degradation certaine et continue de l'etat sanitaire des populations dont temoigne; par exemple; la situation explosive de trypanosomiase humaine africaine eveille la conscience des decideurs nationaux. Cela se traduit par des concepts qui se veulent novateurs telles les strategies avancees ou les strategies mobiles. Les equipes mobiles de l'an 2000 ressortent moins d'une revolution conceptuelle que d'une evolution pour tenir compte au plus pres des modifications dans les moeurs et l'apport technologique. Leur succes repose cependant sur l'abnegation et la competence des hommes appeles a intervenir dans des conditions parfois difficiles

Evaluation de l'integration au Cameroun de la lutte antiglossine dans le Programme des Soins de Sante Primaires

Les auteurs ont mene de decembre 1992 a mai 1993 une enquete tranversale sur la lutte antiglossine au Cameroun. De cette etude; il ressort que plusieurs facteurs ont influe negativement sur l'organisation et le fonctionnement des comites locaux de lutte. Il s'agit notamment du processus assez rigide de la decentralisation; de l'absence de supervision des activites et de la demobilisation des populations due a un manque de motivation et de soutien. L'integration au Cameroun des activites de lutte antiglossine dans le programme des soins de sante primaires n'est pas mauvaise en soi. Les comites locaux de lutte encore en activite fonctionnent a 50 pour cent de leur capacite reelle. Il importe de reformuler la strategie en procedant a une decentralisation progressive; l'implantation des activites et leur entretien restant a la charge des communautes. Une mobilisation urgente des ressources humaines; financieres et materielles s'avere necessaire afin de parer au risque de recrudescence des glossines dans tous les foyers

Strategies de lutte contre les vecteurs de la trypanosomiase humaine africaine

La necessite d'associer campagnes de lutte anti-vectorielle et prospections medicales apparait dans de nombreuses recommandations. Les methodes de lutte ont evolue et l'utilisation de pieges et d'ecrans donne de bons resultats. Tout n'est toujours pas simple et trois exemples en Afrique Centrale (Guinee-Equatoriale; Cameroun et Tchad) montrent que ces campagnes ne s'improvisent pas; qu'il faut en prevoir le financement et veiller a ce qu'elles ne s'interrompent pas trop rapidement

Place du traitement de la trypanosomiase humaine africaine en Trypanosoma brucei gambiense dans l'elaboration de la strategie de lutte

Le but de cet article est de susciter une reflexion sur l'articulation logique des differentes activites de lutte contre la trypanosomiase humaine africaine; en fonction des moyens dont on dispose pour traiter les malades. En effet; on considere trop souvent le depistage comme une finalite; propre a satisfaire les statistiques et les bilans d'activites. L'auteur presente donc le traitement tel qu'il est administre au centre national et au centre regional de la Republique Centrafricaine

La trypanosomiase humaine africaine dans les Etats de l'OCEAC: les vecteurs et les possibilites de leur controle

Au niveau d'un foyer limite; un projet de lutte peut paraitre simple a realiser. Les difficultes viendront; bien sur; de l'etendue du probleme; de sa dimension sous-regionale impliquant six Etats. Mais au-dela des moyens; certainement mobilisables; il faudra une volonte politique des Etats d'assurer la reussite d'un tel projet; face a des blocages; a la degradation des systemes de soin surtout en zone rurale et face a l'image de la maladie du sommeil; maladie oubliee; surtout devant la montee d'autres endemies