61 research outputs found
Importance des interfaces spatiales et temporelles entre les bovins et les glossines dans la transmission de la trypanosomose animale en Afrique de l'Ouest
Lors d'une Ă©tude globale du risque trypanosomien menĂ©e dans la zone agropastorale de SidĂ©radougou (Burkina Faso), des troupeaux sentinelles issus de deux systĂšmes d'Ă©levage diffĂ©rents ont Ă©tĂ© suivis durant deux ans. L'incidence trypanosomienne mensuelle a Ă©tĂ© mesurĂ©e et interprĂ©tĂ©e en fonction des parcours des troupeaux, de leur pratique d'abreuvement et de leur contact avec les glossines ripicoles (Glossina tachinoides et G. palpalis gambiensis). A Nakaka, village d'Ă©leveurs Peuls, la transmission en saison sĂšche est assurĂ©e aux points d'abreuvement pĂ©rennes dans la galerie forestiĂšre. En saison des pluies, les glossines ripicoles se dispersent dans les savanes et infectent les animaux jusque dans les villages. A PĂ©frou, ensemble de campements d'agriculteurs Bobo, les troupeaux sont composĂ©s essentiellement de boeufs de traction. Les animaux issus des campements localisĂ©s Ă proximitĂ© du cours d'eau s'abreuvent dans les points d'eau des formations riveraines et sont infectĂ©s toute l'annĂ©e. L'incidence est plus Ă©levĂ©e en hivernage et en dĂ©but de saison sĂšche, pĂ©riode oĂč les glossines sont les plus nombreuses. A l'opposĂ©, les troupeaux des campements Ă©loignĂ©s du rĂ©seau hydrographique (3 km) sont abreuvĂ©s au puits et ne frĂ©quentent pas les biotopes des glossines. Dans ce paysage essentiellement agricole, les glossines ne se dispersent pas, mĂȘme en saison humide. L'incidence dans les troupeaux est quasiment nulle. Ces rĂ©sultats montrent l'importance des interfaces spatiales et temporelles entre les bovins et les glossines dans l'Ă©pidĂ©miologie des trypanosomoses en Afrique de l'ouest. (RĂ©sumĂ© d'auteur
Importance of post-vaccination sero-surveillance for evaluating efficacy of vaccination programs against endemic diseases of livestock in developing countries
Selection assisted by a BoLA-DR/DQ haplotype against susceptibility to bovine dermatophilosis
Bovine dermatophilosis is a severe skin infection of tropical ruminants inducing a severe loss in productivity and a 15% mortality rate. This disease is caused by the actinomycete bacterium Dermatophilus congolensis associated with the tick Amblyomma variegatum. Currently there are no prospects for a vaccine, and acaricide or antibiotic control is hampered by the development of chemoresistance. Animal breeders have observed that dermatophilosis susceptibility seems to be determined genetically, and we previously identified a BoLA-DRB3-DQB class II haplotype marker for high (R2 = 0.96) susceptibility to the disease. With this marker, we developed a successful eugenic selection procedure for zebu Brahman cattle in Martinique (FWI). Over a period of five years, a marked reduction in disease prevalence, from 0.76 to 0.02 was achieved, and this low level has been maintained over the last two years. The selection procedure, based on a genetic marker system targeting the highly polymorphic BoLA locus, eliminates only those individuals which are at the highest risk of contracting the disease. In the present work, we discuss the properties of this system, including the "heterozygote advantage" and the "frequency dependence" theories, and examine their involvement in the biological mechanisms at the host/pathogen interface. We speculate on the exact role of the MHC molecules in the control of the disease, how the natural selection pressure imposed by the pathogens selectively maintains MHC diversity, and how our results can be practically applied for integrated control of dermatophilosis in developing countries
Ending cervical cancer: A call to action.
The outlook for elimination of the scourge of cervical cancer is bright, because we now have the tools to achieve this goal. In recent years human papillomavirus (HPV) vaccination in high-income countries has resulted in dramatic decreases in HPV infection and associated cervical disease. If all countries with a substantial burden of disease introduce the vaccine nationally, we can protect the vast majority of women and girls most at risk. For women who are beyond the vaccination target age, progress has been made in screening and treatment for cervical precancer, but we must accelerate this momentum to reduce incidence and mortality worldwide to the very low rates found in wealthier countries. Human and financial resources must be increased and directed to programs that follow best practices and reach all women, including the marginalized or disadvantaged. Seven key actions are recommended. Now is the time for action at national, regional, and global levels
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