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

Distribution of Soft Ticks and Their Natural Infection with Borrelia in a Focus of Relapsing Fever in Iran

Tick-borne diseases such as relapsing fever and Crimean-Congo Hemorrhagic Fever (CCHF) are of public health impor&amp;not;tance in Iran. There are 471 reported cases of relapsing fever in 2003, according to the Ministry of Health of Iran.The num&amp;not;ber of cases has been increased in recent years. Its distribution is more or less prevalent in different parts of Iran. The aim of this study was to find out the fauna and natural infection of soft ticks with Borrelia in Qazvin Province, during their sea&amp;not;sonal activity. The province covers 15821 km&amp;sup2; between 48-45 to 50-50 east of Greenwich Meridian of longitude and 35-37 to 36-45 north latitude of the equator. For this purpose a field study was carried out in the region. A total of 54 villages from 19 districts were selected ran&amp;not;domly and ticks were collected from their habitats according to the standard method. A total of 3197 Argasidae ticks were collected from human dwellings, poultry and animal shelters. They belonged to Argas and Or&amp;not;nithodoros genera which 36.8% were Argas persicus, 4% A. reflexus, 6.4% O. canestrini, 45.5% O. lahorensis and 7.3% O. tholozani. It should be noted that 12 ticks of O. erraticus were collected from 12 rodents borrows. We found that 8.82 % of O. tholozani ticks were infected with Borrelia persica and half of the O. erraticus were infected with Borrelia microti. All the people who are in&amp;not;volved with veterinary activities should be aware of disease transmission by the ticks. In the endemic area of the disease tick control is recommended

Ecological and Control Techniques for Sand Flies (Diptera: Psychodidae) Associated with Rodent Reservoirs of Leishmaniasis

BACKGROUND: Leishmaniasis remains a global health problem because of the substantial holes that remain in our understanding of sand fly ecology and the failure of traditional vector control methods. The specific larval food source is unknown for all but a few sand fly species, and this is particularly true for the vectors of Leishmania parasites. We provide methods and materials that could be used to understand, and ultimately break, the transmission cycle of zoonotic cutaneous leishmaniasis. METHODS AND FINDINGS: We demonstrated in laboratory studies that analysis of the stable carbon and nitrogen isotopes found naturally in plant and animal tissues was highly effective for linking adult sand flies with their larval diet, without having to locate or capture the sand fly larvae themselves. In a field trial, we also demonstrated using this technique that half of captured adult sand flies had fed as larvae on rodent feces. Through the identification of rodent feces as a sand fly larval habitat, we now know that rodent baits containing insecticides that have been shown in previous studies to pass into the rodents' feces and kill sand fly larvae also could play a future role in sand fly control. In a second study we showed that rubidium incorporated into rodent baits could be used to demonstrate the level of bloodfeeding by sand flies on baited rodents, and that the elimination of sand flies that feed on rodents can be achieved using baits containing an insecticide that circulates in the blood of baited rodents. CONCLUSIONS: Combined, the techniques described could help to identify larval food sources of other important vectors of the protozoa that cause visceral or dermal leishmaniasis. Unveiling aspects of the life cycles of sand flies that could be targeted with insecticides would guide future sand fly control programs for prevention of leishmaniasis