Dans ce travail, la lutte chimique anti-larvaire a été réalisée au laboratoire chez deux espèces culicidiennes Anopheles hispaniola,vecteur potentiel du paludisme (Guy 1963), et Culex pipiens. Dans ces essais, nous avons utilisé le téméphos, larvicide organophosphoré,sous forme liquide 500 EC (Concentration Emultionnable). Dans ces conditions, un litre de produit commercialcontient 500 g de produit actif (500 g.l-1).Cette étude a montré que la CL50 (30mn) pour le stade L2 est de 21 µg.l-1 chez A.hispaniola et de 10 µg.l-1 chez C. pipiens ;La CL50 (60mn) au stade L4 est respectivement de 23 µg.l-1 et 12 µg.l-1.Le taux de consommation des larves d'A.hispaniola (stade L4) par Gambusia affinis varie en fonction des milieux étudiés maisreste toujours plus élevé chez les femelles que chez les mâles.

Organosoluble extracts from 55 Turkish medicinal plants were tested under standardised conditions for biological activity against third-instar larvae of mosquitoes Aedes aegypti and Anopheles gambiae. Eight extracts demonstrated significant larvicidal activity, with An. gambiae being more susceptible than Ae. aegypti in all cases. The possibility of using indigenous plants for mosquito control is discussed.

The impact of a new design of permethrin-impregnated wall cloth (“Mbu” (mosquito) cloth) on mosquito populations was assessed in Marigat area of Baringo District, Kenya. The cloth was fitted in 2000 houses. Mosquito relative density, species composition and the proportion of blood-fed females before and during the use of the Mbu cloth were monitored by hand catch, exit trap and CDC light trap catches. The common mosquito species were Culex quinquefasciatus, Mansonia uniformis, Anopheles gambiae sensu lato and An. funestus. A statistically significant decline in the mosquito population was observed following the introduction of the cloth. The decline was particularly high during the first and second six month impregnation cycles when it ranged between 43 and 94% indoors. C. quinquefasciatus was less affected by the cloth than other species, while M. uniformis apparently avoided treated houses. An. gambiae s.I. and An. funestus were collected in extremely low numbers during the post-treatment period. The Mbu cloth and other permethrin impregnated wall-hanging fabrics constitute a novel way Of controlling mosquitoes and malaria in rural communities.

Examination of Giemsa stained smears made from the peripheral blood, liver and spleen of hand-caught lizards from West Pokot area showed the presence of seven out of the nine Plasmodium species of lizards which have been previously described in Africa. These species are redescribed using a set of biological characters and procedure which enabled a large quantity of each stage of any species to be studied, measured and compared. The utilization of these characters and procedure was a reaction to the multiple infections in individual lizards and a wide host range of each species among lizard species. The adoption of the criteria is recommended for future taxonomie work on lizard Plasmodia in Africa.

A key which brings together all the previously described species of lizard Plasmodia and the new species encountered in the present investigation is presented. The key is simplified so that it can be of use to epidemiologists and pathologists who may work on saurian malaria in Africa.

During investigations into the epidemiology of malaria of lizards in Kenya, Giemsa-stained smears made from the peripheral blood, liver and spleen of hand-caught lizards from West Pokot district were examined for the presence of Plasmodium species. Ten new species were found and described. These are Plasmodium sapaaensis, P. kyaii, P. kachelibaensis, P. icipeensis, P. gloriai, P. odhiamboi, P. bowiei, P. kaninii, P. kadogoi and P. adunyinkai.

P. sapaaensis was found to be related to P. mabuiae, P. kadogoi to P. rhadinurum, P. kaninii to P. minasense (s. Telford) and P. adunyinkai to P. maculilabre. P. kyaii and P. kachelibaensis have distinct characteristics which distinguish them from the Plasmodium species in the tropiduri group reported so far.

Four species i.e. P. icipeensis, P. odhiamboi, P. gloriai and P. bowiei, exhibited peculiar characteristics most especially their effect on the white cells. They were therefore constituted into the “Kenyan” group.