Comparison of swarming, mating performance and longevity of males Anopheles coluzzii between individuals fed with different natural fruit juices in laboratory and semi-field conditions.

BACKGROUND: It is assumed that malaria vectors feed on locally available nectar sources to obtain energy. Sugar feeding is energetically critical for the Anopheles male swarming and mating activities. However, little is known about the impact of local nectar feeding on male physiological development and its consequences on male mosquito life traits in the malaria control context. This study aimed to evaluate the influence of local fruit juices on the life traits of males Anopheles coluzzii. METHODS: Swarming characteristics (number of males in swarm, number of mating pairs, and swarm duration) in semi-field conditions; mating rate and longevity in a laboratory setting were compared between males An. coluzzii fed exclusively with mango, papaya or banana juices. The trophic preference was investigated in semi-field conditions. RESULTS: The results of this study showed that in the laboratory, mosquitoes fed with papaya juices lived on average longer (10 days) than those fed with banana or mango juices (5 days) and had higher a mating rate (53%) than those fed with banana juice (40%). In the semi-field, the swarm size of mosquitoes fed with banana juice (85 males) was larger than that of mosquitoes fed with mango juice (60 males). The number of mating pairs formed from banana-fed male swarms (17 mating pairs) was higher than that formed from mango-fed male swarm (8 mating pairs). There was no difference in swarming duration between male treatments. Male mosquitoes had a preference for papaya and banana juices. CONCLUSIONS: The results indicate that the origin of plant-derived feeding is an important factor in the survival and reproduction of mosquitoes. This calls for further investigations of chemical contents of nectars and their impact on the physiological development of mosquitoes

Interet D’une Supplementation En Spiruline Chez Les Enfants Drepanocytaires Homozygotes A L’hopital National De Niamey. (Essai Clinique Randomise En Double Aveugle A Propos De 53 Cas)

Spirulina is a micro algae used for thousands of years due to its healing properties. We supplemented children suffering from sickle cell anemia in order to appreciate its impact on the anthropometrical and clinical parameters. It consisted of a randomized clinical double blind test which was carried during a period of 9 months. The study concerned 53 homozygotes children suffering from sickle cell anemia aged 6 months to 15 years. Also, they were visiting the National Hospital of Niamey for follow up. One group (28 children) received 5 g of spirulina daily, and the other group (25 children) received placebo. The aspects studied were: the number of hospitalizations and transfusions, the vaso-occlusive crisis, the body mass index, and the splenomegalia. We found that 84.90% of patients were hospitalized at least once and 45.3% of them have already been transfused. The average number of crisis has greatly decreased in the spirulina group from 2.75 before the study to 1.18 at the end of the study. This, thus, was observed when compared to 2.44 to 1.6 in the placebo group. We also noticed a decrease of the number of hospitalizations and the number of transfusions which is less important in the group supplemented with spirulina. In conclusion, this study showed that supplementation in spirulina had a significant impact on children suffering from sickle cell anemia. This is even despite the fact that the difference between the two groups is not significant in some cases

Isolation and characterization of Bacillus thuringiensis (Ernst Berliner) strains indigenous to agricultural soils of Mali.

The objective of this work was to isolate and characterize Bacillus thuringiensis from agricultural and other insect breeding sites in Mali. A hundred soil samples were collected from Bamako district, Segou, Sikasso and Timbuktu regions. B. thuringiensis (Bt) was isolated from the samples using a heat-acetate method and the isolates were identified and classified using morphological and biochemical tests. The frequency of B. thuringiensis in soils was noted. The results showed that, 15 out of the 3111 bacterial isolates were putative Bt. thuringiensis. Most isolates produced parasporal crystals. The average Bt index for all the areas sampled was 5.1%; the highest frequency was recorded for Niono in Segou region (11.7) and the lowest for Bozola in Bamako district (0.5). Contrary the known information on the high content and distribution of B. in soils, the agricultural soils of Mali contain few Bt strains, confirmed by the low Bt index obtained

Nanofluid impingement jet heat transfer

Experimental investigation to study the heat transfer between a vertical round alumina-water nanofluid jet and a horizontal circular round surface is carried out. Different jet flow rates, jet nozzle diameters, various circular disk diameters and three nanoparticles concentrations (0, 6.6 and 10%, respectively) are used. The experimental results indicate that using nanofluid as a heat transfer carrier can enhance the heat transfer process. For the same Reynolds number, the experimental data show an increase in the Nusselt numbers as the nanoparticle concentration increases. Size of heating disk diameters shows reverse effect on heat transfer. It is also found that presenting the data in terms of Reynolds number at impingement jet diameter can take into account on both effects of jet heights and nozzle diameter. Presenting the data in terms of Peclet numbers, at fixed impingement nozzle diameter, makes the data less sensitive to the percentage change of the nanoparticle concentrations. Finally, general heat transfer correlation is obtained verses Peclet numbers using nanoparticle concentrations and the nozzle diameter ratio as parameters

Mating competitiveness of sterile genetic sexing strain males (GAMA) under laboratory and semi-field conditions: Steps towards the use of the Sterile Insect Technique to control the major malaria vector Anopheles arabiensis in South Africa

BACKGROUND : Anopheles arabiensis Patton is primarily responsible for malaria transmission in South Africa after successful suppression of other major vector species using indoor spraying of residual insecticides. Control of An. arabiensis using current insecticide based approaches is proving difficult owing to the development of insecticide resistance, and variable feeding and resting behaviours. The use of the sterile insect technique as an area-wide integrated pest management system to supplement the control of An. arabiensis was proposed for South Africa and is currently under investigation. The success of this technique is dependent on the ability of laboratory-reared sterile males to compete with wild males for mates. As part of the research and development of the SIT technique for use against An. arabiensis in South Africa, radio-sensitivity and mating competitiveness of a local An. arabiensis sexing strain were assessed. METHODS : The optimal irradiation dose inducing male sterility without compromising mating vigour was tested using Cobalt 60 irradiation doses ranging from 70-100 Gy. Relative mating competitiveness of sterile laboratory-reared males (GAMA strain) compared to fertile wild-type males (AMAL strain) for virgin wild-type females (AMAL) was investigated under laboratory and semi-field conditions using large outdoor cages. Three different sterile male to fertile male to wild-type female ratios were evaluated [1:1:1, 5:1:1 and 10:1:1 (sterile males: fertile, wild-type males: fertile, wild-type females)]. RESULTS : Irradiation at the doses tested did not affect adult emergence but had a moderate effect on adult survivorship and mating vigour. A dose of 75 Gy was selected for the competitiveness assays. Mating competitiveness experiments showed that irradiated GAMA male mosquitoes are a third as competitive as their fertile AMAL counterparts under semi-field conditions. However, they were not as competitive under laboratory conditions. An inundative ratio of 10:1 induced the highest sterility in the representative wild-type population, with potential to effectively suppress reproduction. CONCLUSION : Laboratory-reared and sterilised GAMA male An. arabiensis at a release ratio of 3:1 (3 sterile males to 1 wild, fertile male) can successfully compete for insemination of wild-type females. These results will be used to inform subsequent small-scale pilot field releases in South Africa.The Nuclear Technologies in Medicine and the Bioscience Initiatives (NTeMBI), a national platform developed and managed by the South African Nuclear Energy Corporation and supported by the Department of Science and Technology. Funding was also provided in part from the National Research Foundation, the International Atomic Energy Agency (Contracts 17904, SAF5013 and SAF16780/ under the G34002) and a Global Diseases Detection/CDC grant (U19GH000622-01 MAL01).http://www.parasitesandvectors.comam2016Paraclinical Science