Ecology: a prerequisite for malaria elimination and eradication

* Existing front-line vector control measures, such as insecticide-treated nets and residual sprays, cannot break the transmission cycle of Plasmodium falciparum in the most intensely endemic parts of Africa and the Pacific * The goal of malaria eradication will require urgent strategic investment into understanding the ecology and evolution of the mosquito vectors that transmit malaria * Priority areas will include understanding aspects of the mosquito life cycle beyond the blood feeding processes which directly mediate malaria transmission * Global commitment to malaria eradication necessitates a corresponding long-term commitment to vector ecolog

Gender Roles in Small Holder Dairy Farming: Pertinent Issues on Access and Control over Dairy Farming in Arumeru District, Tanzania

A study on gender roles in dairy farming and management was conducted in Arumeru district, Tanzania. The study involved women in dairy farming groups and those not in groups. The objective of this study was to assess gender role in dairy farming and management, access and control over income obtained as well as, animal ownership, decision making  and opportunities in dairy farming system in Arumeru. Cross sectional research design was adopted using structured questionnaires to collect information from households from six villages namely Bangata, Sasi, Inshupu, Enaboishu, Sokoni II and Nkoaranga. Descriptive analysis and Chi-square were used to test the statistical significance of categorical and continuous data respectively. The results showed that women contribute more labour force in dairy management than men, those women who were not in groups did not have a full access and control over dairy farming enterprise. Furthermore, it was observed that those women in groups were in a good position to overcome traditional practice. Women who belonged to groups controlled and had access to resources such as livestock (dairy cattle) and income generated from them. However, since most of the farmer groups were still infants, it has been recommended that the women groups should get financial assistance from the government agencies. Similarly, in conjunction with encouraging more women to join groups, gender relations in dairy management should be reassessed to minimize the work load burden to women which affects the level of production and sustainability of the dairy enterprise. Keywords: Access and control, dairy management, gender, women groups.

Socio-Cultural Determinants of Entrepreneurial Capabilities among the Chagga and Sukuma Small and Medium Enterprises in Tanzania

This paper examines socio-cultural determinants (SCDs) linked to entrepreneurial capabilities (EC) among the Chagga and Sukuma Small and Medium Enterprises (SMEs) in Tanzania. A survey of 254 owner-managers was conducted in Kilimanjaro and Mwanza regions in order to collect quantitative data and case studies for qualitative data. Descriptive statistics and Binary Logistic Regression Model analysis were employed in estimating the effect of SCDs on EC. Results show that values, social factors, beliefs, norms and perceptions demonstrate positive effects while attitudes show a negative effect on EC among the Chagga and Sukuma. However, results show variation on the effect of SCD on EC between the Chagga and Sukuma in which the effect is stronger among the Chagga than Sukuma. This study concludes that SCDs have effect on EC and its implication is that individuals exposed to such SCDs are likely to have a sounding EC. The study recommends that policy makers should consider the role of SCDs in entrepreneurial undertaking. Keywords: Socio-cultural Determinants, Entrepreneurial Capabilities, Chagga, Sukuma, SMEs, Tanzani

Mathematical Evaluation of Community Level Impact of Combining Bed Nets and Indoor Residual Spraying upon Malaria Transmission in Areas where the main Vectors are Anopheles Arabiensis Mosquitoes.

Indoor residual insecticide spraying (IRS) and long-lasting insecticide treated nets (LLINs) are commonly used together even though evidence that such combinations confer greater protection against malaria than either method alone is inconsistent. A deterministic model of mosquito life cycle processes was adapted to allow parameterization with results from experimental hut trials of various combinations of untreated nets or LLINs (Olyset, PermaNet 2.0, Icon Life nets) with IRS (pirimiphos methyl, lambda cyhalothrin, DDT), in a setting where vector populations are dominated by Anopheles arabiensis, so that community level impact upon malaria transmission at high coverage could be predicted. Intact untreated nets alone provide equivalent personal protection to all three LLINs. Relative to IRS plus untreated nets, community level protection is slightly higher when Olyset or PermaNet 2.0 nets are added onto IRS with pirimiphos methyl or lambda cyhalothrin but not DDT, and when Icon Life nets supplement any of the IRS insecticides. Adding IRS onto any net modestly enhances communal protection when pirimiphos methyl is sprayed, while spraying lambda cyhalothrin enhances protection for untreated nets but not LLINs. Addition of DDT reduces communal protection when added to LLINs. Where transmission is mediated primarily by An. arabiensis, adding IRS to high LLIN coverage provides only modest incremental benefit (e.g. when an organophosphate like pirimiphos methyl is used), but can be redundant (e.g. when a pyrethroid like lambda cyhalothin is used) or even regressive (e.g. when DDT is used for the IRS). Relative to IRS plus untreated nets, supplementing IRS with LLINs will only modestly improve community protection. Beyond the physical protection that intact nets provide, additional protection against transmission by An. arabiensis conferred by insecticides will be remarkably small, regardless of whether they are delivered as LLINs or IRS. The insecticidal action of LLINs and IRS probably already approaches their absolute limit of potential impact upon this persistent vector so personal protection of nets should be enhanced by improving the physical integrity and durability. Combining LLINs and non-pyrethroid IRS in residual transmission systems may nevertheless be justified as a means to manage insecticide resistance and prevent potential rebound of not only An. arabiensis, but also more potent, vulnerable and historically important species such as Anopheles gambiae and Anopheles funestus

Eliminating Malaria Vectors.

Malaria vectors which predominantly feed indoors upon humans have been locally eliminated from several settings with insecticide treated nets (ITNs), indoor residual spraying or larval source management. Recent dramatic declines of An. gambiae in east Africa with imperfect ITN coverage suggest mosquito populations can rapidly collapse when forced below realistically achievable, non-zero thresholds of density and supporting resource availability. Here we explain why insecticide-based mosquito elimination strategies are feasible, desirable and can be extended to a wider variety of species by expanding the vector control arsenal to cover a broader spectrum of the resources they need to survive. The greatest advantage of eliminating mosquitoes, rather than merely controlling them, is that this precludes local selection for behavioural or physiological resistance traits. The greatest challenges are therefore to achieve high biological coverage of targeted resources rapidly enough to prevent local emergence of resistance and to then continually exclude, monitor for and respond to re-invasion from external populations

Evaluation of the Safety and Immunogenicity of the RTS,S/AS01E Malaria Candidate Vaccine When Integrated in the Expanded Program of Immunization

Background. The RTS,S/AS01E malaria candidate vaccine is being developed for immunization of African infants through the Expanded Program of Immunization (EPI). Methods. This phase 2, randomized, open, controlled trial conducted in Ghana, Tanzania, and Gabon evaluated the safety and immunogenicity of RTS,S/AS01E when coadministered with EPI vaccines. Five hundred eleven infants were randomized to receive RTS,S/AS01E at 0, 1, and 2 months (in 3 doses with diphtheria, tetanus, and wholecell pertussis conjugate [DTPw]; hepatitis B [HepB]; Haemophilus influenzae type b [Hib]; and oral polio vaccine [OPV]), RTS,S/AS01E at 0, 1, and 7 months (2 doses with DTPwHepB/Hib+OPV and 1 dose with measles and yellow fever), or EPI vaccines only. Results. The occurrences of serious adverse events were balanced across groups; none were vaccine-related. One child from the control group died. Mild to moderate fever and diaper dermatitis occurred more frequently in the RTS,S/AS01E coadministration groups. RTS,S/AS01E generated high anti-circumsporozoite protein and anti- hepatitis B surface antigen antibody levels. Regarding EPI vaccine responses upon coadministration when considering both immunization schedules, despite a tendency toward lower geometric mean titers to some EPI antigens, predefined noninferiority criteria were met for all EPI antigens except for polio 3 when EPI vaccines were given with RTS,S/AS01E at 0, 1, and 2 months. However, when antibody levels at screening were taken into account, the rates of response to polio 3 antigens were comparable between groups. Conclusion. RTS,S/AS01E integrated in the EPI showed a favorable safety and immunogenicity evaluation. Trial registration. ClinicalTrials.gov identifier: NCT00436007. GlaxoSmithKline study ID number: 106369 (Malaria-050

Methanethiol-dependent dimethylsulfide production in soil environments

Dimethylsulfide (DMS) is an environmentally important trace gas with roles in sulfur cycling, signalling to higher organisms and in atmospheric chemistry. DMS is believed to be predominantly produced in marine environments via microbial degradation of the osmolyte dimethylsulfoniopropionate (DMSP). However, significant amounts of DMS are also generated from terrestrial environments, for example, peat bogs can emit ~6 μmol DMS m−2 per day, likely via the methylation of methanethiol (MeSH). A methyltransferase enzyme termed ‘MddA’, which catalyses the methylation of MeSH, generating DMS, in a wide range of bacteria and some cyanobacteria, may mediate this process, as the mddA gene is abundant in terrestrial metagenomes. This is the first study investigating the functionality of MeSH-dependent DMS production (Mdd) in a wide range of aerobic environments. All soils and marine sediment samples tested produced DMS when incubated with MeSH. Cultivation-dependent and cultivation-independent methods were used to assess microbial community changes in response to MeSH addition in a grassland soil where 35.9% of the bacteria were predicted to contain mddA. Bacteria of the genus Methylotenera were enriched in the presence of MeSH. Furthermore, many novel Mdd+ bacterial strains were isolated. Despite the abundance of mddA in the grassland soil, the Mdd pathway may not be a significant source of DMS in this environment as MeSH addition was required to detect DMS at only very low conversion rates

Socio-Economic Determinants of Vulnerability to Climate Variability and Change Across Gender in Southeast Nigeria

This study assessed vulnerability problems in Southeast Nigeria. The specific objectives were to, assess vulnerability to impacts of climate variability and change (CVC) and their differences across gender and identify socio-economic determinants of vulnerability in the area. Mixed research methods and approaches, including key informant interview, focus group discussion, field observations and household survey (questionnaire), were used to collect qualitative and quantitative data.  The data were analysed and presented using mean, chi-square and multinomial logit regression. Common vulnerability problems for the entire sample (pooled data) as well as men and women headed households include poverty, less ownership of asset, rain fed nature of farming among others.  Vulnerability conditions of women in terms of their institutional and user characteristics, showed that they were significantly different (p≤0.05) from men in issues of limited availability of cropping lands (X2=67.71), political will-power (X2=64.48) and aids (X2=59.12). Socioeconomic characteristics of respondents affects their vulnerability problems such as limited availability of aids (P≤ =0.000; Cox and Snell R2 = 0.53; -2log likelihood ratio = 45.78); less ownership of assets among others. Socio economic determinants of vulnerability include age, income, education among others. The study recommends the use of gender-specific and equitable interventions such as providing trainings in line with needs of men and women to improve their information, technologies, knowledge and capacity to reduce vulnerability in the area

Socio-Economic Determinants of Vulnerability to Climate Variability and Change Across Gender in Southeast Nigeria

This study assessed vulnerability problems in Southeast Nigeria. The specific objectives were to, assess vulnerability to impacts of climate variability and change (CVC) and their differences across gender and identify socio-economic determinants of vulnerability in the area. Mixed research methods and approaches, including key informant interview, focus group discussion, field observations and household survey (questionnaire), were used to collect qualitative and quantitative data.  The data were analysed and presented using mean, chi-square and multinomial logit regression. Common vulnerability problems for the entire sample (pooled data) as well as men and women headed households include poverty, less ownership of asset, rain fed nature of farming among others.  Vulnerability conditions of women in terms of their institutional and user characteristics, showed that they were significantly different (p≤0.05) from men in issues of limited availability of cropping lands (X2=67.71), political will-power (X2=64.48) and aids (X2=59.12). Socioeconomic characteristics of respondents affects their vulnerability problems such as limited availability of aids (P≤ =0.000; Cox and Snell R2 = 0.53; -2log likelihood ratio = 45.78); less ownership of assets among others. Socio economic determinants of vulnerability include age, income, education among others. The study recommends the use of gender-specific and equitable interventions such as providing trainings in line with needs of men and women to improve their information, technologies, knowledge and capacity to reduce vulnerability in the area