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Resistance of mosquitoes to insecticides is mainly attributed to their adaptation to insecticide-based vector control interventions. Although pesticides used in agriculture have been frequently mentioned as an additional force driving the selection of resistance, only a few studies were dedicated to validate this hypothesis. The objective of this study was to investigate the effect of exposure of the malaria mosquito, Anopheles gambiae s.s. larvae for 72h to sub-lethal concentrations of the agrochemical mixture (pesticides, herbicides and fungicides). Their subsequent tolerances were measured to deltamethrin (pyrethroid), DDT (organochlorine) and bendiocarb (carbamate) currently used for vector control. The mean LC50 was determined and tolerance ratios for larvae exposed to agrochemical comparatively with unexposed larvae were calculated and expressed as fold increased tolerance. Bioassays revealed a significant increase in larval tolerance to detamethrin (1.83-2.86 fold), DDT (1.31-1.53 fold) and bendiocarb (1.14-1.19 fold) following exposure to 0.1 µM and 1 µM agrochemical mixture. The observed increased tolerance in this study is likely to be based on metabolic resistance mechanisms. Overall, this study reveals the potential of agrochemicals to increase the tolerance of mosquito larvae to chemical insecticides.

Capacity building is considered a priority for health research institutions in developing countries to achieve the Millennium Development Goals by 2015. However, in many countries including Tanzania, much emphasis has been directed towards human resources for health with the total exclusion of human resources for health research. The objective of this study was to systematically investigate the capacity building process for the Tanzanian National Institute for Medical Research (NIMR) over a 30-year period and identify the challenges and opportunities in creating a critical mass of multi-disciplinary research scientists that is required for achieving the intended health benefits. A desk review of personnel database was conducted for information covering 1980-2009 on academic qualifications, training, research experience and research output. The current staff curriculum vitae (CV) were reviewed to gather information on researchers' employment record, training, training support, area of expertise and scientific output. Interviews were conducted with a cross section of researchers on capacity development aspects using a self-administered questionnaire. In-depth interviews were also conducted with the current and former NIMR Management to seek information on capacity development challenges. A review was also done on staff personal files, annual reports, strategic plans and other occasional documents. A total of 163 CV were assessed; of these, 76.7% (125) were for Research Scientists (RS), 20.9% (34) Laboratory Technologists (LT) and 2.4% (4) for System Analysts. The Institute had 13 research scientists upon its establishment. Since 1980, NIMR has recruited a total of 185 Research Scientists. By 2009, NIMR had a total scientific workforce of 170 staff (RS= 82.4%; LT= 17.6%). Of the 140 RSs, 37 (26.4%), were first degree; 77 (55.5%) second degree while 26 (18.6%) were PhD degree holders. Of the total of 78 researchers interviewed, 55 (70.5%) indicated to have accessed postgraduate training through their personal efforts and 23 through institutional arrangement. Sixty (77%) respondents were satisfied with their tenure at NIMR. Seventy (89%) indicated that they had not at any point considered leaving NIMR. Most (79%) research scientists were recruited while holding a first degree, a few (17%) with second degree while only one (0.7%) holding a PhD degree. NIMR has experienced a research scientist attrition rate of 17.5%. Staff retention factors included availability of training opportunities; passion for conducting research; and good career prospects. Despite having a training programme, the institute has never at any moment been able to hold its own training resources. Being a public research institution, NIMR receives its core funding from the government of the United Republic of Tanzania. The bulk of the funding appears to be spent on personnel emoluments that take up to 85% (mean = 66%) of the allocated budget. In conclusion, the current NIMR's research capacity building is dependent mainly on foreign funding and personal initiatives. There is an urgent need to increase local funding for capacity building and conduct of research. A programme should be put in place to ensure sustainability of the capacity building process.

Malaria transmission varies from one area to another and there are also local difference in time and space. The objective of the study was to determine the local variability of entomological parameters namely, mosquito abundance, human biting rate (HBR), sporozoite rate for Plasmodiumfalciparum and entomological inoculation rate (EIR). The study was carried out in Rufiji District south eastern Tanzania from October 2001 and September 2004. Adult mosquitoes were collected indoors by CDC light traps. PCR was employed to identify the species within the Anopheles gambiae complex. ELISA was used to determine the sporozoite rate. Over a three year sampling period a total of 64,875 female mosquitoes were caught using light-traps, and of these 28% were Anopheles gambiae complex, 25% An. funestus Giles, 1% An. pharoensis Theobald, 46% Culex species and the rest were Mansonia uniformis Theobald. Mosquito abundance and species composition varied seasonally, spatially and between years. Using PCR, three members of the Anopheles gambiae complex namely An. gambiae s.s. Giles (69%), An. arabiensis Paton (23%) and An. merus D6nitz (7%) were confirmed to occur in the study area. Plasmodiumfalciparum circumsporozoite antigen (CSA) rates were 3.5% for An. gambiae complex and 2.3% for An. funestus. The mean EIR ranged from 28-275 infective bites/person/year. Transmission indices varied over short distances, seasonally and between years. In conclusion, malaria transmission indices in the study area are one of the highest in Tanzania; and there is high variability of entomological parameters over a small geographical area.

An entomological survey to determine resting behaviour and species composition of malaria vectors was carried out in Uyui District in western Tanzania in May 2009. Mosquitoes were collected using indoor resting catch, window exit trap and outdoor "bed-net" techniques. The mosquitoes were identified using morphological key and polymerase chain reaction (PCR). A total of 672 Anopheles gambiae sensu lato were collected. Of these, 661 (98.4%) were collected outdoor whereas few (1.6%) were collected indoor. The exit trap catch: mechanical aspirator catch ratio was 1:1.75. The overall indoor resting density of An. gambiae s.l. as determined by mechanical aspirator and exit trap was 0.7 and 0.5 mosquitoes per room, respectively. The overall density of the host-seeking as determined by bed net trap outdoor was 44.1 mosquitoes per person. A sample of 44 specimens taken randomly from morphologically identified An.gambiae s.l. population was further analyzed to species level using PCR techniques. Of these 44 specimens 26 (59%) and 18 (41%) were Anopheles arabiensis and Anopheles gambiae sensu stricto respectively. This study contributes to the understanding of the distribution of malaria vectors with respect to species composition and their resting behaviour that could contribute to vector control operations in western Tanzania. A longitudinal study considering dry and wet seasons is recommended to provide more information on the seasonal distribution, abundance and biting behaviour of malaria vectors in the study area.

Globally, tuberculosis-HIV co-infections are on the increase. In 2007, 15% (1.37 million) of the tuberculosis cases were HIV-positive tuberculosis (TB). This cross-sectional study was conducted in February 2009 to assess the effect of the level of CD4 lymphocyte counts on the development of smear positive pulmonary TB (PTB) among HIV patients before and after initiation of highly active antiretroviral therapy (HAART). A total of 155 HIV patients who were on HAART programme were enrolled and out of these 42 (27.1%) were smear positive PTB. Of the 42 PTB patients, 38 (90.5%) were also infected with HIV and were already at initiation of HAART. There was no association between the development of smear positive PTB and socio-demographic characteristics among HIV patients before and after HAART initiation (P>0.05). A larger proportion of HIV+PTB patients diagnosed before and after HAART initiation was found with CD4 lymphocyte count <200cells/microl. However, the difference was not statistically significant (P =0.092). Among HIV patients who were diagnosed to be smear positive PTB after HAART initiation, their CD4 lymphocyte counts at time of TB diagnosis was lower than their CD4 lymphocyte counts at time of HAART initiation. The four patients diagnosed with PTB after HAART initiation had mean CD4 lymphocyte counts at HAART initiation not statistically different from that at TB diagnosis (t=0.715, P=0.526). The median time period within which the diagnosis of smear positive PTB was made after HAART initiation was 22 weeks and the mean time was 66.75 weeks. These findings provide evidence that development of smear positive PTB after HAART initiation may occur at any level of CD4 lymphocyte count (P<0.05). This study was limited by the relatively small sample size, we therefore recommend more studies involving a larger sample size in order to estimate more accurately the effect of both level of CD4 lymphocyte count and HAART on the development of smear positive PTB among HIV patients on treatment.

A 1-year longitudinal study was conducted in Magugu in Babati district, northern Tanzania to determine malaria vector population structure and malaria transmission indices. Mosquitoes were sampled using the Centre for Disease Control (CDC) light traps. A total of 110,357 adult female mosquitoes were collected. Anopheles gambiae s.1. accounted 25% of the total female mosquito collected. Relatively fewer An. funestus were collected. Other mosquito species collected were An. pharoensis, An. coustani, An. maculipalpis, An. marshallii, Culex quinquefasciatus, Cx unnivittatus, Mansonia uniformis and Ma. africana. An analysis by Polymerase Chain Reaction revealed that An. arabiensis was the only member of the An. gambiae complex in the collected samples. The number of mosquito collected correlated with the increasing mean rainfall. Blood meal analysis showed a higher human enzymatic reaction among An. gambiae s.1. (63.5%) followed by An. funestus (42.9%). Bovine enzymatic reaction was higher among An. coustani (73.7%) followed by the An. pharoensis (66.7%). The Enzyme Linked Immunosorbent Assay (ELISA) was used to detect Plasmodium falciparum circumsporozoites proteins in 10,000 female Anopheles mosquitoes. Only two An. arabiensis were found to be infected. The entomological inoculation rate (EIR) was estimated at 0.51 infectious bites per person per year. This EIR was considered to be relatively low, indicating that malaria transmission in this area is low. Variability in mosquito blood meal shows availability of variety of preferred blood meal choices and impact of other factors inhibiting mosquito-human host contact. The study has provided information considered useful in the mapping of the vector distribution and population structure in the country. Such information is considered to be among the essential tools for planning malaria control interventions.