Africa Technical Research Center

Arusha, Tanzania

Africa Technical Research Center

Arusha, Tanzania
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Kweka E.J.,Tropical Pesticides Research Institute | Kweka E.J.,Catholic University of Health and Allied Sciences | Lee M.-C.,University of California at Irvine | Mwang'Onde B.J.,Tropical Pesticides Research Institute | And 4 more authors.
BMC Research Notes | Year: 2017

Background: Indoor residual spraying (IRS) is one of the preferred tools used for control of malaria in many settings in the world. However, this control tool still faces challenges that include lack of long lasting active ingredient, limited number of well-trained personal, and need of repeated treatment which increases operational costs and reduces acceptability by residents. As a result there is need to develop and validate other methods which can complement the existing controls. The current study compared the bio-efficacy of durable wall lining (DL) (treated with deltamethrin 265 mg/m2) and IRS (with deltamethrin 5% WP at 20 mg/m2) on indoor mosquitoes densities and biting behaviour of mosquitoes in comparison with control houses without either DL or IRS. Methods: A study with two treatment arms and a control was conducted in Magugu ward, Northern Tanzania. Overall, a total of 60 houses were selected for the study with 20 houses per treatment arm and control. From each arm and control five houses were selected for mosquitoes trapping. Mosquitoes were sampled from 18:00 to 07:00 hourly every month for a period of 6 months. Mosquitoes were sampled using CDC miniature light traps. Results: A total of 14,400 female wild mosquitoes were used for contact bioassays in the control arm. 20 houses were sprayed, additionally walls of 20 houses were installed with wall liners, and walls of 20 unsprayed houses were used as control. Also, a total of 946 mosquitoes were sampled with traps in 60 houses during the hourly sampling for 6 months. A total of 3000 unfed females of An. gambiae s.l. wild population raised from larvae were collected from natural habitats in the same village for bioassays. The decline in indoor mosquitoes densities observed in this study did not lead to a shift in the biting cycles (P = 0.712). The number of mosquitoes caught indoors in houses with DL and IRS was significantly lower (P < 0.001) compared to control houses. When the comparisons were done between DL and IRS houses, the densities were significantly lower in DL houses compared to IRS houses (P = 0.021). In the DL installed houses, indoor mosquito density declined notably and sustained throughout the 6 months of the study. However, in those houses sprayed with deltamethrin 5% WP (Pali™5 WP), the density noted to start to increase within four months after spraying(do you mean to say that the densities declined up to 4 months post spraying and thereafter increased. Conclusions: Considering the efficacy duration of DL against IRS with deltamethrin 5% WP on mosquito densities decline indoors. The results of this study suggest that DL is more effective in malaria control as its efficacy lasted more than that of IRS. © 2017 The Author(s).

Manangwa O.,Vector and Vector Borne Disease Institute | Nkwengulila G.,University of Dar es Salaam | Ouma J.O.,Africa Technical Research Center | Ouma J.O.,Kenya Agricultural Research Institute | And 7 more authors.
Parasites and Vectors | Year: 2017

Background: Tsetse flies (Diptera: Glossinidae) are sole vectors for trypanosomiasis, which affect human health and livestock productivity in Africa. Little is known about the genetic diversity of Glossina fuscipes fuscipes, which is an important species in Tanzania and Kenya. The main objective of the study was to provide baseline data to determine the genetic variability and divergence of G. f. fuscipes in the Lake Victoria basin of Tanzania and Kenya in order to guide future vector control efforts in the region. Findings: Two hundred and seventy five G. f. fuscipes from 8 sites along the shores of Lake Victoria were screened for genetic polymorphisms at 19 microsatellite loci. Samples were collected from two sites in Kenya and six sites in Tanzania. Four of the Tanzanian sites were located in the Rorya district, on the eastern shores of Lake Victoria, while the other two sites were from Ukerewe and Bukoba districts from the southern and western Lake Victoria shores, respectively. Four genetically distinct allopatric clusters were revealed by microsatellite analysis, which sorted the sampling sites according to geography, with sites separated by as little as ~65 km belonging to distinct genetic clusters, while samples located within ~35 km from each other group in the same cluster. Conclusion: Our results suggest that there is ongoing genetic admixture within sampling sites located ~35 km from each other, while sites located ~65 km apart are genetically isolated from each other. Similar patterns emerged from a parallel study on G. f. fuscipes analyzed from the Lake Victoria Uganda shores. From a control perspective these results suggest that for sites within the same genetic cluster, control efforts should be carried out in a coordinated fashion in order to avoid re-invasions. Future work should focus on better quantifying the extent and spatial patterns of the observed genetic discontinuities of the G. f. fuscipes populations along the Tanzanian shores. This will aid in their control by providing guidelines on the geographical extent of the area to be treated at the same time. © 2017 The Author(s).

Manangwa O.,Vector and Vector Borne Disease Institute | Ouma J.O.,Africa Technical Research Center | Ouma J.O.,Kenya Agricultural Research Institute | Malele I.,Vector and Vector Borne Disease Institute | And 3 more authors.
Livestock Research for Rural Development | Year: 2016

Tsetse flies transmit trypanosomes which affect livestock and human health in sub Saharan african countries including Tanzania.The wide occurrence of this disease in people and their livestock has negatively impacted the development of viable agricultural systems in many areas of great agricultural potential including areas of the Lake Victoria basin in Tanzania.The present study investigated trypanosome infection rate in G. f. fuscipes in Kirongwe, Masonga, Rasi Nyabero and Tobwe River in Rorya district, Msozi village in Ukerewe district and Kemondo in rural Bukoba district during the dry and wet seasons. Trypanosome infection in cattle was also investigated in the same villages except Kemondo village with a view to understand the risk of the disease to livestock and humans in the study area.Tsetse flies were collected using biconical and pyramidal traps in Kirongwe, Masonga, Rasi Nyabero and Tobwe River.Twenty traps were deployed after every 150 to 200 meters during the dry season and wet season. A total of 120 flies were examined microscopically and 215 by Polymerization Chain Reaction (PCR) for trypanosome infection. Trypanosomes infection in cattle was also assessed in order to understand the risk of the disease to cattle and humans in the study area. Blood was collected from 116 cattle and examined under microscope for trypanosome infection. Some blood was stored in FTA cards for trypanosome infection rate analysis using PCR. No infection was detected microscopically but PCR showed (2%) of G. f. fuscipes was infected by T. b. brucei at Rasi Nyabero village during the dry season. Similarly, for the wet season, one female fly (2.5%) out of 40 was found positive for T. congolense Kilifi in Msozi village. Microscopic examination showed no cattle were infected but PCR indicated one female cow out of 116 cows (0.86%) at Rasi Nyabero village was infected with T. vivax. Generally, trypanosome prevalence in G. f. fuscipes and cattle was low for all seasons. The low infection rate should not be taken for granted, regular surveillance is important in monitoring the problem in the study area since the Lake Victoria shore is known to be a risk area for trypanosomiasis. © 2016, Fundacion CIPAV. All rights reserved.

Simon S.,CIRAD - Agricultural Research for Development | Simon S.,INRAB Institute National des Recherches Agricoles du Benin | Komlan F.A.,INRAB Institute National des Recherches Agricoles du Benin | Adjaito L.,INRAB Institute National des Recherches Agricoles du Benin | And 4 more authors.
International Journal of Pest Management | Year: 2014

In Africa, synthetic pesticide applications are overly frequent and above labelled rates. We assessed the efficacy of an insect net physical control system on field cabbage (Brassica oleracea var. capitata) production in France and Benin. Various mesh sizes and netting removal frequencies were compared under contrasting climatic conditions. Studies under Mediterranean climatic conditions (spring season) compared two mesh sizes (0.73 mm and 1.6 mm). Studies under subequatorial climatic conditions (cool and hot seasons) tested nets of mesh size 0.4 mm and 0.9 mm used either as permanent cover, removed daily, or 3 days per week. The results showed that a fine mesh did not improve the netting efficacy against pests but had a major impact on the microclimate. In Mediterranean climatic conditions, the netting efficacy and beneficial microclimate improved crop yields. In subequatorial conditions, crop yields were lowest with permanent net protection due to high temperatures under the nets and poor aphid and Spodoptera littoralis control. Removing the nets 3 days per week was a good technical/economic trade-off, ensuring acceptable efficacy with minimal effects on the microclimate. © 2014 Taylor & Francis.

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