On-Farm Evaluation of Hermetic Technology Against Maize Storage Pests in Kenya.

On-farm trial with a total of 32 farmers in eight villages of Naivasha and Nakuru areas of Kenya was conducted between December 2013 and September 2014 to evaluate hermetic grain storage technologies under farmers' management conditions. The storage technologies evaluated were metal silo and SuperGrain IV-R bag alongside the standard woven polypropylene bag with or without Actellic super dust. Moisture content, insect population, grain discoloration, and weight loss were analyzed 90, 180, and 270 d after storage. Grain moisture content remained stable over the storage period. Both metal silo and SuperGrain IV-R bag suppressed insect population, prevented grain loss and cross-infestation of insects from the surrounding environment. On the contrary, polypropylene bags allowed rapid build up of insect population and re-infestation from the surrounding environment. Grain weight losses were 1.5% in the metal silo and 1.8% in the SuperGrain IV-R bags compared to 32% in the polypropylene bags without Actellic Super dust, 270 d after storage. The present study, therefore, demonstrates that storing grains either in metal silo or SuperGrain IV-R bags would benefit farmers in reducing grain losses and improving quality. The study was of great interest to the farmers, grain storage scientists, and food security experts.

Effects of long-lasting insecticidal nets and zooprophylaxis on mosquito feeding behaviour and density in Mwea, central Kenya.

BACKGROUND & OBJECTIVES: Zooprophylaxis is a strategy that can control malaria by attracting mosquitoes to domestic animals that act as dead-end hosts. The objective of this study was to establish the effects of zooprophylaxis and long-lasting insecticidal nets (LLINs) on malaria transmission in an agro-based ecosystem with seasonal transmission. METHODS: The mosquito samples were collected indoors using the space spray catch method before and after intervention between October 2005 and March 2006 to determine the mosquito densities and the feeding patterns of Anopheles spp in Mwea, Kenya. RESULTS: A total of 4148 mosquito samples were collected, out of which 11 (0.2%) were tested positive for sporozoites. Ten were Anopheles gambiae species and one was An. funestus species. Results on blood meal ELISA showed that in the household categories that used bednets and kept one cow there was a decrease in relative change ratio (post-/pre-intervention) of 87.5 and 19.6% (p <0.05) in human and cattle blood intake respectively. For households that kept 2-4 cattle and used bednets, there was a decrease in cattle blood index (CBI) by 61.9% and an increase in human blood index (HBI) by 2%, which was not significant (p <0.05). In households with <4 cattle and bednet, there was significant reduction (p >0.05) in CBI of 37.5% as compared to the reduction of 10.3% in HBI. The ratios of man biting rates (MBR) decreased significantly, as you move up from households with one cattle with or without LLINs to households with more than four cattle with or without LLINs with a regression coefficient of -0.96; SE = 0.834; p = 0.017. Similarly, the HBI decreased significantly with the regression coefficient of 0.239; SE = 0.039; p = 0.015 (p <0.05) especially in households with >4 cattle. INTERPRETATION & CONCLUSION: This study demonstrated that there were additive effects of zooprophylaxis and LLINs in the control of mosquito density and reduction of human risk to the mosquito bites. However, in Integrated Vector Management (IVM), the number of animals per household should not be more than four.

Host acceptance, suitability, and effects of host deprivation on the West African egg parasitoid Telenomus isis (Hymenoptera: Scelionidae) reared on East African stemborers under varying temperature and relative humidity regimens.

Scelionid egg parasitoids of Telenomus spp. have been shown to significantly affect noctuid stemborer populations and yields of maize in western Africa. One of them, T. isis, has never been reported from eastern Africa and was introduced into the laboratories of the International Centre of Insect Physiology and Ecology, Kenya. This study evaluates the biotic potential of T. isis using East African stemborers as hosts. Host acceptance was tested using 15 lepidopteran borer species. Only noctuid stemborers were accepted for oviposition by T. isis. Sesamia calamistis Hampson, Sesamia nonagrioides (Lefebvre), and Busseola fusca (Fuller) were further used to study the effect of host species, host age, duration of host deprivation, temperature, and humidity on the performance of the parasitoid. In contrast to sex ratio, developmental time, parasitism, and parasitoid emergence varied significantly with host species, and the former two decreased with the age of host eggs. Female longevity increased with duration of host deprivation, whereas average lifetime fecundity decreased, probably because of oocyte resorption. T. isis successfully developed between 18 and 32 degrees C at both low (40-50%) and high (70-80%) relative humidity regimens, but temperature played a more critical role. Using the modified Logan model, the lower and upper temperature thresholds for development were estimated at 11.5 and 37.5 degrees C, respectively, with an optimum at 30.5 degrees C for both humidity regimens. Depending on temperature and relative humidity regimen, the intrinsic rate of increase (r(m)) varied from 0.077 to 0.300, net reproductive rate (R(o)) from 7.70 to 83.96, and generation time (G) from 11 to 38 d. The results of this study indicate that T. isis is likely to establish in eastern Africa.

Survey on prevalence and risk factors on HIV-1 among pregnant women in North-Rift, Kenya: a hospital based cross-sectional study conducted between 2005 and 2006.

BACKGROUND: The HIV/AIDS epidemic in Kenya is a major public-health problem. Estimating the prevalence of HIV in pregnant women provides essential information for an effective implementation of HIV/AIDS control measures and monitoring of HIV spread within a country. The objective of this study was to determine the prevalence of HIV infection, risk factors for HIV/AIDS and immunologic (lymphocyte profile) characteristics among pregnant women attending antenatal clinics in three district hospitals in North-Rift, Kenya. METHODS: Blood samples were collected from pregnant women attending antenatal clinics in three district hospitals (Kitale, Kapsabet and Nandi Hills) after informed consent and pre-test counseling. The samples were tested for HIV antibodies as per the guidelines laid down by Ministry of Health, Kenya. A structured pretested questionnaire was used to obtain demographic data. Lymphocyte subset counts were quantified by standard flow cytometry. RESULTS: Of the 4638 pregnant women tested, 309 (6.7%) were HIV seropositive. The majority (85.1%) of the antenatal attendees did not know their HIV status prior to visiting the clinic for antenatal care. The highest proportion of HIV infected women was in the age group 21-25 years (35.5%). The 31-35 age group had the highest (8.5%) HIV prevalence, while women aged more than 35 years had the lowest (2.5%).Women in a polygamous relationship were significantly more likely to be HIV infected as compared to those in a monogamous relationship (p = 0.000). The highest HIV prevalence (6.3%) was recorded among antenatal attendees who had attended secondary schools followed by those with primary and tertiary level of education (6% and 5% respectively). However, there was no significant relationship between HIV seropositivity and the level of education (p = 0.653 and p = 0.469 for secondary and tertiary respectively). The mean CD4 count was 466 cells/mm3 (9-2000 cells/mm3). Those that had less than 200 cells/mm3 accounted for 14% and only nine were on antiretroviral therapy. CONCLUSION: Seroprevalence of HIV was found to be consistent with the reports from the national HIV sentinel surveys. Enumeration of T-lymphocyte (CD4/8) should be carried out routinely in the antenatal clinics for proper timing of initiation of antiretroviral therapy among HIV infected pregnant women.

Prevalence of nevirapine-associated resistance mutations after single dose prophylactic treatment among antenatal clinic attendees in north rift Kenya.

The use of single dose nevirapine to prevent mother-to-child transmission of HIV has been reported to induce drug-resistant mutations and reduce options for antiretroviral treatment for HIV-infected mothers and their children. To explore the status of nevirapine-resistant HIV genotypes in rural hospitals in the North Rift Valley Province of Kenya, samples collected 3 months after single dose nevirapine from 36 mothers and their children were analyzed. Resistance mutations were genotypically evaluated through proviral DNA amplification, cloning, and sequencing. Ten mothers (27.8%) had antiretroviral-associated resistance mutations of whom four (11.1%) had specific nevirapine (NNRTI) resistance-associated mutations. Three mothers (8.3%) transmitted the infection to their infants. This presence of nevirapine mutations in rural antenatal clinic attendees confirms the importance of integrating antiretroviral resistance monitoring as a key component in programs geared to prevention of HIV mother-to-child transmission.

Pathogenicity of Metarhizium anisopliae (Metsch.) Sorokin and Beauveria bassiana (Balsamo) Vuillemin, to three adult fruit fly species: Ceratitis capitata (Weidemann), C. rosa var. fasciventris Karsch and C. cosyra (Walker) (Diptera :Tephritidae).

The pathogenicity of two isolates of Beauveria bassiana and 12 of Metarhizium anisopliae towards adult fruit flies, Ceratitis capitata and Ceratitis rosa var. fasciventris was tested in the laboratory. Fruit flies were exposed to dry conidia evenly spread on velvet material covering the inner side of a cylindrical plastic tube. All isolates tested were pathogenic to both species of fruit flies. Mortality ranged from 7 to 100% in C. capitata and from 11.4 to 100% in C. rosa var. fasciventris at 4 days post-inoculation. Six isolates, M. anisopliae ICIPE 18, 20, 32, 40, 41 and 62, were highly pathogenic to both C. capitata and C. rosa var. fasciventris. The LT90 values of the most pathogenic isolates ranged between 3-4 days in both insects. Because of the difficulties in rearing C. cosyra, only the isolates that were highly pathogenic to both C. rosa var. fasciventris and C. capitata were tested against adult C. cosyra. They caused mortality of between 72-78% at 4 days post-inoculation. The LT90 values in all the isolates did not exceed 4 days. One of the most pathogenic isolates, M. anisopliae ICIPE 20, was evaluated against C. capitata and C. rosa var. fasciventris in cage experiments using three autoinoculators (maize cob, cheesecloth and Petri dish) in an autoinoculative device consisting of plastic mineral bottle. Mortality of between 70-93% was observed in flies of both species that were captured from the cages and held under laboratory conditions. These results indicate the possibility of fruit fly suppression with entomopathogenic fungi using an autoinoculative device.