Continuous mapping identifies Loci associated with weevil resistance [Cosmopolites sordidus (Germar)] in a triploid banana population

Open Access Journal; Published online: 29 Nov 2021The first step towards marker-assisted selection is linking the phenotypes to molecular markers through quantitative trait loci (QTL) analysis. While the process is straightforward with self-pollinating diploid species, QTL analysis in polyploids requires unconventional methods. In this study, we have identified markers associated with weevil Cosmopolites sordidus (Germar) resistance in banana using 138 triploid (2n = 3x) hybrids derived from a cross between a tetraploid ‘Monyet’ (2n = 4x) and a diploid ‘Kokopo’ (2n = 2x) banana genotypes. The population was genotyped by DArTSeq, resulting in 18,009 polymorphic SNPs between the two parents. Marker–trait association was carried out by continuous mapping where the adjusted trait means for corm peripheral damage (PD) and total cross-section damage (TXD), both on the logit scale, were regressed on the marker allele frequencies. Forty-four SNPs were identified that were associated with corm peripheral damage on the chromosomes 5, 6 and 8 with 41 of them located on chromosome 6 and segregating in ‘Kokopo’. Eleven SNPs associated with corm total cross-section damage were identified on chromosome 6 and segregating in ‘Monyet’. The additive effect of replacing one reference allele with the alternative allele was determined at each marker position. The peripheral damage QTL was confirmed using conventional QTL linkage analysis in the simplex markers segregating in ‘Kokopo’ (AAAA × RA). We also identified 43 putative genes in the vicinity of the markers significantly associated with the two traits. The identified loci associated with resistance to weevil damage will be used in the efforts of developing molecular tools for marker-assisted breeding in banana

Implementing school malaria surveys in Kenya: towards a national surveillance system

OBJECTIVE: To design and implement surveys of malaria infection and coverage of malaria control interventions among school children in Kenya in order to contribute towards a nationwide assessment of malaria. METHODS: The country was stratified into distinct malaria transmission zones based on a malaria risk map and 480 schools were visited between October 2008 and March 2010. Surveys were conducted in two phases: an initial opportunistic phase whereby schools were selected for other research purposes; and a second phase whereby schools were purposively selected to provide adequate spatial representation across the country. Consent for participation was based on passive, opt-out consent rather than written, opt-in consent because of the routine, low-risk nature of the survey. All children were diagnosed for Plasmodium infection using rapid diagnostic tests, assessed for anaemia and were interviewed about mosquito net usage, recent history of illness, and socio-economic and household indicators. Children's responses were entered electronically in the school and data transmitted nightly to Nairobi using a mobile phone modem connection. RDT positive results were corrected by microscopy and all results were adjusted for clustering using random effect regression modelling. RESULTS: 49,975 children in 480 schools were sampled, at an estimated cost of US$ 1,116 per school. The overall prevalence of malaria and anaemia was 4.3% and 14.1%, respectively, and 19.0% of children reported using an insecticide-treated net (ITN). The prevalence of infection showed marked variation across the country, with prevalence being highest in Western and Nyanza provinces, and lowest in Central, North Eastern and Eastern provinces. Nationally, 2.3% of schools had reported ITN use >60%, and low reported ITN use was a particular problem in Western and Nyanza provinces. Few schools reported having malaria health education materials or ongoing malaria control activities. CONCLUSION: School malaria surveys provide a rapid, cheap and sustainable approach to malaria surveillance which can complement household surveys, and in Kenya, show that large areas of the country do not merit any direct school-based control, but school-based interventions, coupled with strengthened community-based strategies, are warranted in western and coastal Kenya. The results also provide detailed baseline data to inform evaluation of school-based malaria control in Kenya

Livestock versus Wildlife Ranching in Kenyan Rangelands: A Case Study of Laikipia District Ranches

Past research has shown that livestock ranching per se has failed to sustain economic development in Laikipia district. Exploratory study results of livestock-wildlife mixed ranching in the district over the last two years are discussed. The results reveal a web of interactive factors involving land tenur, livestock development, disease control, marketing and environmental conservation that need to be considered if the newly emerging mixed -livestock ranching system can be feasible. Failure to consider this web of interactions has contributed to constraints in the efforts to develop a viable livestock –wildlife mixed ranching system. Attempts that could lead to amelioration of these constraints are suggested in this paper. The Kenya Veterinarian Vol. 27 2004: pp. 24-3

Feasibility and acceptability of mobile phone data collection for longitudinal follow-up among patients treated for obstetric fistula in Uganda

Rapid dissemination of mobile technology provides substantial opportunity for overcoming challenges reaching rural and marginalized populations. We assessed feasibility and acceptability of longitudinal mobile data capture among women undergoing fistula surgery in Uganda (n = 60) in 2014-2015. Participants were followed for 12 months following surgery, with data captured quarterly, followed by interviews at 12 months. Participant retention was high (97%). Most respondents reported no difficulty with mobile data capture (range 93%-100%), and preferred mobile interview (88%-100%). Mobile data capture saved 1000 person-hours of transit and organizational time. Phone-based mobile data collection provided social support. Our results support this method for longitudinal studies among geographically and socially marginalized populations

Integrated community-directed intervention for schistosomiasis and soil transmitted helminths in western Kenya – a pilot study

<p>Abstract</p> <p>Background</p> <p>Schistosome and soil-transmitted helminth (STH) infections are recognized as major global public health problems, causing severe and subtle morbidity, including significant educational and nutritional effects in children. Although effective and safe drugs are available, ensuring access to these drugs by all those at risk of schistosomiasis and STHs is still a challenge. Community-directed intervention (CDI) has been used successfully for mass distribution of drugs for other diseases such as onchocerciasis and lymphatic filariasis. A national control programme is yet to be instituted in Kenya and evidence for cost-effective strategies for reaching most affected communities is needed. This study evaluated the effectiveness and feasibility of the CDI strategy in the control of schistosomiasis and STHs, in East Uyoma location, Rarieda district, a community of western Kenya that is highly endemic for both infections.</p> <p>Results</p> <p>Pre-treatment prevalence of <it>S. mansoni</it> averaged 17.4% (range 5-43%) in the entire location. Treatment coverage in different villages ranged from 54.19 to 96.6% by community drug distributor (CDD) records. Assessment from a household survey showed coverage of 52.3 -91.9% while the proportion of homesteads (home compounds) covered ranged from 54.9-98.5%. Six months after one round of drug distribution, the prevalence levels of <it>S. mansoni,</it> hookworm and <it>Trichuris trichura</it> infections were reduced by 33.2%, 69.4% and 42.6% respectively.</p> <p>Conclusions</p> <p>This study shows that CDI is an accepted and effective strategy in the mass treatment of schistosomiasis and STH infections in resource constrained communities in Kenya and may be useful in similar communities elsewhere. A controlled trial comparing CDI and school based mass drug administration to demonstarte their relative advantages is ongoing.</p