Leishmania tropica au Maroc. III. Rôle vecteur de Phlebotomus sergenti. A propos de 89 isolats.

In a Moroccan focus of cutaneous leishmaniasis caused by Leishmania tropica, 7,907 female sandflies captured with CDC traps were dissected from summer to autumn 1989. Among species of the genus Phlebotomus, only P. sergenti harbored promastigotes. Eighty-nine strains belonging to the complex L. tropica were isolated. The frequency of vector infection was zero in June, rose to 1.3% in August, and reached 9.9% in October, which indicates that the period of high risk is at the end of the hot season. Out of 89 strains isolated, 74 were completely typed and corresponded to the following four zymodemes: MON-102 (one strain), MON-107 (56 strains), MON-122 (two strains), and MON-123 (15 strains). Only the first two were observed in humans. The distribution of zymodemes MON-102 and MON-107 was very different in humans, dogs, and the vector. In one of the sites surveyed, which was strongly dominated by MON-107, the absence of human cases involving this zymodeme suggests the existence of a wild reservoir

Infestation naturelle de Phlebotomus ariasi et Phlebotomus perniciosus (Diptera, Psychodidae) par Leishmania infantum (Kinetoplastida-Trypanosomatidae) en Catalogne (Espagne)

Deux enquêtes successives sur les vecteurs de Leishmania infantum, réalisées dans le Priorat (Catalogne, Espagne), ont permis la dissection de 8 329 Phlébotomes ♀ dont 6 775 Larroussius (2 123 Phlebotomus ariasi et 4 652 P. perniciosus). Au total dix- huit souches ont été isolées chez ce même sous-genre et rapportées, par l'analyse enzymatique, à L. infantum MON-1, MON-29, MON-77. Ces souches se répartissent entre P. ariasi (11 souches : quatre MON-1, sept MON-29) et P. perniciosus (sept souches : un MON-1, cinq MON-29, un MON-77). Par ailleurs un chien, originaire du même foyer, hébergeait un quatrième zymodème (MON-105) mis en évidence au laboratoire par gorgement sur P. perniciosus d'élevage

Insecticide susceptibility status of Phlebotomus (Paraphlebotomus) sergenti and Phlebotomus (Phlebotomus) papatasi in endemic foci of cutaneous leishmaniasis in Morocco

<p>Abstract</p> <p>Background</p> <p>In Morocco, cutaneous leishmaniasis is transmitted by <it>Phlebotomus sergenti </it>and <it>Ph. papatasi</it>. Vector control is mainly based on environmental management but indoor residual spraying with synthetic pyrethroids is applied in many foci of <it>Leishmania tropica</it>. However, the levels and distribution of sandfly susceptibility to insecticides currently used has not been studied yet. Hence, this study was undertaken to establish the susceptibility status of <it>Ph. sergenti </it>and <it>Ph. papatasi </it>to lambdacyhalothrin, DDT and malathion.</p> <p>Methods</p> <p>The insecticide susceptibility status of <it>Ph. sergenti </it>and <it>Ph. papatasi </it>was assessed during 2011, following the standard WHO technique based on discriminating dosage. A series of twenty-five susceptibility tests were carried out on wild populations of <it>Ph. sergenti </it>and <it>Ph. papatasi </it>collected by CDC light traps from seven villages in six different provinces. Knockdown rates (KDT) were noted at 5 min intervals during the exposure to DDT and to lambdacyhalothrin. After one hour of exposure, sandflies were transferred to the observation tubes for 24 hours. After this period, mortality rate was calculated. Data were analyzed by Probit analysis program to determine the knockdown time 50% and 90% (KDT50 and KDT90) values.</p> <p>Results</p> <p>Study results showed that <it>Ph.sergenti </it>and <it>Ph. papatasi </it>were susceptible to all insecticides tested. Comparison of KDT values showed a clear difference between the insecticide knockdown effect in studied villages. This effect was lower in areas subject to high selective public health insecticide pressure in the framework of malaria or leishmaniasis control.</p> <p>Conclusion</p> <p><it>Phlebotomus sergenti </it>and <it>Ph. papatasi </it>are susceptible to the insecticides tested in the seven studied villages but they showed a low knockdown effect in Azilal, Chichaoua and Settat. Therefore, a study of insecticide susceptibility of these vectors in other foci of leishmaniasis is recommended and the level of their susceptibility should be regularly monitored.</p

Is the meiofauna a good indicator for climate change and anthropogenic impacts?

Our planet is changing, and one of the most pressing challenges facing the scientific community revolves around understanding how ecological communities respond to global changes. From coastal to deep-sea ecosystems, ecologists are exploring new areas of research to find model organisms that help predict the future of life on our planet. Among the different categories of organisms, meiofauna offer several advantages for the study of marine benthic ecosystems. This paper reviews the advances in the study of meiofauna with regard to climate change and anthropogenic impacts. Four taxonomic groups are valuable for predicting global changes: foraminifers (especially calcareous forms), nematodes, copepods and ostracods. Environmental variables are fundamental in the interpretation of meiofaunal patterns and multistressor experiments are more informative than single stressor ones, revealing complex ecological and biological interactions. Global change has a general negative effect on meiofauna, with important consequences on benthic food webs. However, some meiofaunal species can be favoured by the extreme conditions induced by global change, as they can exhibit remarkable physiological adaptations. This review highlights the need to incorporate studies on taxonomy, genetics and function of meiofaunal taxa into global change impact research

Dynamique de l’autogenèse dans les populations naturelles d’

Utilisant des larves néonates d’Aedes detritus (espèce jumelle A), laissées à demeure dans leur gîte naturel ou placées en enceintes sous température et lumière contrôlées, les auteurs mettent en évidence l’influence de la photopériode sur l’expression du caractère autogène. Aussi bien in situ qu’en condition expérimentale, la fréquence de l’autogenèse est favorisée par les photopériodes à jour court. Les photopériodes à jour long inhibent le processus. Le rôle de la température paraît accessoire, sinon nul