A New Napier Grass Stunting Disease in Kenya Associated With Phytoplasma

Napier grass (Pennisetum purpureum Schum) is a cultivated elephant grass native to Eastern and Central Africa forming the major livestock feed on East African smallholder dairy farms (Valk, 1990) as it is suitable for cut and carry zero-grazing management systems. Although several plant pathogens have been described historically they were seldom severe. However, in the 1970s there was an outbreak of snow mould fungal disease caused by Beniowskia spheroidea that attacked most varieties of napier grass. A napier grass variety (clone 13) was bred which is resistant to the disease. In the 1990s two major outbreaks of napier grass diseases occurred in Kenya. In Central Kenya a napier grass head smut caused by Ustilago kamerunensis H Sydow and Sydow in 1992 and in Western Kenya a napier grass stunting disease was first reported in Bungoma in 1997. A similar stunting disease had been reported in Uganda (Tilley, 1969), which was suspected to be a virus transmitted by insects. This new outbreak of napier grass stunting disease is of major concern as it attacks all varieties of napier grass. The main objective of this study was to survey the extent of the disease and to identify the organism causing this disease

A New Napier Grass Stunting Disease in Kenya Associated with Phytoplasma

Napier grass (Pennisetum purpureum Schum) is a cultivated elephant grass native to Eastern and Central Africa forming the major livestock feed on East African smallholder dairy farms (Valk, 1990) as it is suitable for cut and carry for zero-grazing management systems. Although several plant pathogens have been described historically they were seldom severe. However, in 1970s there was an outbreak of snow mould fungal disease caused by Beniowskia spheroidea that attacked most varieties of napier grass. A napier grass variety clone 13 was bred which is resistant to the disease. In the 1990s two major outbreaks of napier grass diseases occurred in Kenya. In Central Kenya a napier grass head smut caused by Ustilago kamerunensis H Sydow and Sydow in 1992 and in Western Kenya a napier grass stunting disease was first reported in Bungoma in 1997. A similar stunting disease had been reported in Uganda (Tilley, 1969), which was suspected to be a virus transmitted by insects. This new outbreak of napier grass stunting disease is of major concern as it attacks all varieties of napier grass. The main objective of this study was to survey the extent of the disease and to identify the organism causing this disease

The use of simple sequence repeats markers to study genetic diversity in maize genotypes resistant to gray leaf spot disease

Genetic diversity in maize (Zea mays L.) is an important tool for progress in selection for traits of interest. The objective of this study was to screen genotypes for presence of markers linked to plantdefense against fungal diseases, and to study the genetic diversity in gray leaf spot resistant maize genotypes. Forty-one genotypes comprising of collections from Kenya, International Maize and WheatImprovement Centre, the International Institute for Tropical Agriculture and South Africa were identified to be resistant to gray leaf spot in Kenya in 2004. The genotypes were analyzed for variability by usingtwenty-eight microsatellite markers covering the entire maize genome. The results indicated diversity among lines for selected markers. Based on the diversity tree, ten clusters were observed. All genotypes occurred in clusters, except for genotypes EC573- (R12) C8S3-14-1, REGN 99/6, H623 and VHCY. The data indicated that, at least one line in each cluster showed a relationship in a locus with a corresponding parent. Occurrence of related lines also implied that there were common alleles that could have contributed to the gray leaf spot resistance

Genotype by environment interactions and yield stability of stem borer resistant maize hybrids in Kenya

In a maize breeding program, potential genotypes are usually evaluated in different environments before desirable ones are selected. Genotype x environment (G x E) interaction is associated with the differential performance of genotypes tested at different locations and in different years, and influences selection and recommendation of cultivars. Twenty one stem borer resistance maize hybrids and four commercial checks were evaluated in six environments in Kenya under infestation with Chilo partellus and Busseola fusca to determine the G x E interactions and stability of the hybrids. Analysis of variance was conducted for grain yield, days to flowering and plant and ear height. Stability for grain yield was determined using genotype plus genotype by environment interaction (GGE) biplot analysis. Variances due to genotype, environment and G x E interaction effects were highly significant for all traits. The GGE biplot showed that four experimental hybrids and two commercial checks had positive PC1 score indicating above average performance across environments. However, 10 experimental hybrids and two commercial checks had negative PC1 score, suggesting poor average performance. Experimental hybrids, CKIR07004 and CKIR07013, were highly desirable in terms of grain yield (>7.5 t/ha) and stability across environments. These hybrids could be released in Kenya and similar environments.Key words: Genotype x environment (G x E) interactions, maize, stem borer resistant hybrids, stability

Participatory Farmer Evaluation of Stem borer Resistant Maize varieties in three maize growing ecologies of Kenya

Insect Resistant Maize for Africa Project (IRMA) aims at developing and deploying insect resistant maize varieties to reduce grain losses due to insect pests. As part of incorporating farmer’s perceptions and improving the adoption of the developed varieties, participatory approaches are adopted. The paper analysis farmer’s preferences of maize germplasm developed through conventional breeding. The paper uses data collected from evaluations conducted at the end of 2006 April and October rains. Nine stem borer resistant maize varieties were evaluated alongside six commercial checks in the moist transitional zones (East and West) at vegetative and harvest stage, while in the dry transitional zone and dry mid altitude zones, 6 new varieties were evaluated together with four commercial checks at harvest stage. Each variety was assessed on a scale of 1(very poor) to 5 (very good) based on key criteria generated in earlier group discussions with farmers and overall score. Data was analyzed using ordinal regression model of Social Package for Social Sciences (SPSS). In DT zone, Katumani, CKIR06007 and CKIR06008 were more preferred to the checks based on overall score. CKIR06008 was also more preferred on yield and tolerance to insect pest criteria, while CKIR04002, CKIR06009, and CKIR04003 were perceived more superior to local check based on tolerance to insect pests. In moist transitional zone Embu only CKIR06005 was more preferred (p<0.01) to the check at harvest stage in April 2006 season based on early maturity. While there was no preference for the new varieties at vegetative stage in Embu in October rains 2006 season, a number of new varieties CKIR06001, CKIR06002, CKIR06003, CKIR06004, and CKIR06005 were more preferred based on early maturity at harvest in October rains 2006 season. In the moist transitional zone (west), CKIR06005 and CKIR06005 were more preferred on maturity criteria but CKIR06004 also had good attributes in terms of cob size vegetative stage in April rains 2007. We conclude that farmers perceive some varieties to have good tolerance to insect pests in addition to good yield and maturity characteristics attributes, which are critical to the farmers in the adoption of new varieties.Crop Production/Industries,

Malaria and Helminth Co-infections in School and Preschool Children: A Cross-sectional Study in Magu district, north-Western Tanzania.

Malaria, schistosomiasis and soil transmitted helminth infections (STH) are important parasitic infections in Sub-Saharan Africa where a significant proportion of people are exposed to co-infections of more than one parasite. In Tanzania, these infections are a major public health problem particularly in school and pre-school children. The current study investigated malaria and helminth co-infections and anaemia in school and pre-school children in Magu district, Tanzania. School and pre-school children were enrolled in a cross-sectional study. Stool samples were examined for Schistosoma mansoni and STH infections using Kato Katz technique. Urine samples were examined for Schistosoma haematobium using the urine filtration method. Blood samples were examined for malaria parasites and haemoglobin concentrations using the Giemsa stain and Haemoque methods, respectively. Out of 1,546 children examined, 1,079 (69.8%) were infected with one or more parasites. Malaria-helminth co-infections were observed in 276 children (60% of all children with P. falciparum infection). Malaria parasites were significantly more prevalent in hookworm infected children than in hookworm free children (p = 0.046). However, this association was non-significant on multivariate logistic regression analysis (OR = 1.320, p = 0.064). Malaria parasite density decreased with increasing infection intensity of S. mansoni and with increasing number of co-infecting helminth species. Anaemia prevalence was 34.4% and was significantly associated with malaria infection, S. haematobium infection and with multiple parasite infections. Whereas S. mansoni infection was a significant predictor of malaria parasite density, P. falciparum and S. haematobium infections were significant predictors of anaemia. These findings suggest that multiple parasite infections are common in school and pre-school children in Magu district. Concurrent P. falciparum, S. mansoni and S. haematobium infections increase the risk of lower Hb levels and anaemia, which in turn calls for integrated disease control interventions. The associations between malaria and helminth infections detected in this study need further investigation

Prevalence Distribution and Risk Factors for Schistosoma hematobium Infection among School Children in Blantyre, Malawi

Schistosoma hematobium infection is a parasitic infection endemic in Malawi. Schistosomiasis usually shows a focal distribution of infection and it is important to identify communities at high risk of infection and assess effectiveness of control programs. We conducted a survey in one district in Malawi to determine prevalence and factors associated with S. hematobium infection among primary school pupils. Using a questionnaire, information on history of passing bloody urine and known risk factors associated with infection was collected. Urine samples were collected and examined for S. hematobium eggs. One thousand one hundred and fifty (1,150) pupils were interviewed, and out of 1,139 pupils who submitted urine samples, 10.4% were infected. Our data showed that male gender, child's knowledge of an existing open water source (includes river, dam, springs, lake, etc.) in the area, history of urinary schistosomiasis in the past month, distance of less than 1 km from school to nearest open water source and age 8–10 years compared to those 14 years and older were independently associated with infection. These findings suggest that children attending schools in close proximity to open water sources are at increased risk of infection

Hookworm-Related Anaemia among Pregnant Women: A Systematic Review

Anaemia affects large numbers of pregnant women in developing countries and increases their risk of dying during pregnancy and delivering low birth weight babies, who in turn are at increased risk of dying. Human hookworm infection has long been recognized among the major causes of anaemia in poor communities, but understanding of the benefits of the management of hookworm infection in pregnancy has lagged behind the other major causes of maternal anaemia. Low coverage of anthelmintic treatment in maternal health programmes in many countries has been the result. After systematically reviewing the available literature we observed that increasing hookworm infection intensity is associated with lower haemoglobin levels in pregnant women. We also estimate that between a quarter and a third of pregnant women in sub-Saharan Africa are infected with hookworm and at risk of preventable hookworm-related anaemia. However, all identified intervention studies showed a benefit of deworming for maternal or child health and we argue that increased efforts should be made to increase the coverage of anthelmintic treatment among pregnant women

Neglected Tropical Diseases in Sub-Saharan Africa: Review of Their Prevalence, Distribution, and Disease Burden

The neglected tropical diseases (NTDs) are the most common conditions affecting the poorest 500 million people living in sub-Saharan Africa (SSA), and together produce a burden of disease that may be equivalent to up to one-half of SSA's malaria disease burden and more than double that caused by tuberculosis. Approximately 85% of the NTD disease burden results from helminth infections. Hookworm infection occurs in almost half of SSA's poorest people, including 40–50 million school-aged children and 7 million pregnant women in whom it is a leading cause of anemia. Schistosomiasis is the second most prevalent NTD after hookworm (192 million cases), accounting for 93% of the world's number of cases and possibly associated with increased horizontal transmission of HIV/AIDS. Lymphatic filariasis (46–51 million cases) and onchocerciasis (37 million cases) are also widespread in SSA, each disease representing a significant cause of disability and reduction in the region's agricultural productivity. There is a dearth of information on Africa's non-helminth NTDs. The protozoan infections, human African trypanosomiasis and visceral leishmaniasis, affect almost 100,000 people, primarily in areas of conflict in SSA where they cause high mortality, and where trachoma is the most prevalent bacterial NTD (30 million cases). However, there are little or no data on some very important protozoan infections, e.g., amebiasis and toxoplasmosis; bacterial infections, e.g., typhoid fever and non-typhoidal salmonellosis, the tick-borne bacterial zoonoses, and non-tuberculosis mycobaterial infections; and arboviral infections. Thus, the overall burden of Africa's NTDs may be severely underestimated. A full assessment is an important step for disease control priorities, particularly in Nigeria and the Democratic Republic of Congo, where the greatest number of NTDs may occur