RP-Department of Zoological Sciences

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Abundance of Insect Pests and their Effects on Biomass Yields of Single vs. Multi-species Planted Fallows
(Springer Netherlands, 2006) Ogol, C.K.P.O.; Girma, H.; Rao, M. R.; Day, R.
Indigenous and exotic leguminous shrubs that are promising for planted fallow for soil fertility replenishment in east and southern Africa have been found to harbour many herbivorous insects, giving suspicion that widespread adoption of fallow systems may aggravate insect pests. Studies were conducted on farms in western Kenya from 1999 to 2001 to monitor the abundance of herbivorous insects and assess their effects on biomass yields of pure and mixed fallows. The treatments tested were single and two-species mixtures of Tephrosia vogelii, Sesbania sesban and Crotalaria grahamiana and a natural fallow in a split plot design, with the fallow systems in the main plots and protection vs. no protection against insects in sub-plots spread over six farms. Eighteen insect species belonging to seven orders and 14 families were identified as pests of␣the fallows with varied abundance and infestation level across the sites. While Hilda patruelis and Amphicallia pactolicus were most damaging to C. grahamiana, Mesoplatys ochroptera was detrimental to S.␣sesban. T. vogelii hosted fewer insects than others. Nevertheless the pest infestation did not cause significant biomass yield reduction during the study period. Pest attack was generally greater in villages that had been testing the planted fallows for some years compared with villages that took up the fallows recently. This indicates the potential for increased pest infestation with increased adoption of the system by farmers. Multi-species fallows did not indicate any advantage over single species fallows in terms of either reduced pest incidence or increased biomass production.
Abundance, population dynamics and impact of the leucaena psyllid Heteropsylla cubana Crawford in a maize-leucaena agroforestry system in Kenya
(Cambridge University Press, 1997-06) Ogol, C.K.P.O.; Spence, J. R.
We monitored abundance, population dynamics and damage impacts of the leucaena psyllid Heteropsylla cubana Crawford (Homoptera: Psyllidae) in a maize-leucaena agroforestry system. The abundance of local ladybird beetle predator populations were also evaluated. The studies were conducted between June 1993 and November 1995 at Mtwapa and Amoyo in coastal and western Kenya respectively. Alley-cropping leucaena with maize had no effect on the abundance of the leucaena psyllid or its coccinellid predators. Therefore, neither the ‘resource concentration’ hypothesis nor the ‘enemies’ hypothesis corroborated for the psyllid-leucaena system within the spatial scale of this study. Psyllid populations were generally much higher at Mtwapa than at Amoyo, suggesting possible environmental effects on population growth. Psyllid populations were influenced by weather (mainly rainfall) and availability of suitable shoots. New growth of young shoots following rainfall encouraged psyllid abundance as long as weather conditions were not extreme. Though population of the generalist ladybird beetles was correlated with that of its psyllid prey, beetles did not appear to have significant effect on prey populations
Acceptance and suitability of four lepidopteran stemborers for the development of the pupal parasitoid Xanthopimpla stemmator (Hymenoptera: Ichneumonidae)
(Taylor & Francis, 2005) Gitau, C. W.; Ngi-Song, A. J.; Otieno, S.A.; Overholt, W. A.
Xanthopimpla stemmator (Thunberg), a solitary endoparasitoid of lepidopteran stemborer pupae, was recently imported into East Africa as a candidate biological control agent of gramineous stemborers. Suitability of Busseola fusca Fuller, Chilo partellus (Swinhoe), Eldana saccharina (Walker) and Sesamia calamistis Hampson, for the development of X. stemmator was studied in the laboratory. One- to 6-day-old laboratory reared pupae of the four stemborer species were exposed to naïve X. stemmator females. All host pupae and ages were acceptable for oviposition. The parasitoids inflicted multiple probe wounds on 67.8% of pupae exposed. B. fusca, C. partellus and S. calamistis were equally suitable with 56.4, 59.4 and 52.3%, respectively, of probed pupae leading to emergence of adult parasitoids. E. saccharina was less suitable with only 22.6% of probed pupae producing parasitoids. Emergence of parasitoids did not differ significantly across the six pupal ages for B. fusca and S. calamistis, but varied for C. partellus and E. saccharina. No parasitoids emerged from 6-day-old E. saccharina pupae. Realized fecundity of females reared on the four stemborer pupae showed that fewer progeny were produced by females emerging from E. saccharina than females reared on the other three stemborer species. Eldana saccharina may be a poor host for X. stemmator in Kenya, but this parasitoid is a potential candidate for biological control of B. fusca, C. partellus and S. calamistis.
Activation of peroxisome proliferator– activated receptor gamma induces anti-inflammatory properties in the chicken free avian respiratory macrophages
(BioMed Central, 2015) Mutua, Mbuvi P.; Steinaa, Lucilla; Muya, Shadrack M.; Gicheru, Muita M.
Background: Activation of peroxisome proliferator activated receptor gamma (PPAR γ) in the alveolar macrophages (AM) by selective synthetic PPAR γ ligands, improves the ability of the cells to resolve inflammation. In birds, respiratory macrophages are known as free avian respiratory macrophages (FARM) and show distinct functional differences from AM. The effects of treating FARM with PPAR γ ligands are unclear. Methods: FARM were harvested by lavage of chicken respiratory tract and their morphology assessed at microscopic level. The effects of PPAR γ agonists on the FARM in vitro viability, phagocytic capacity and proinflammatory cytokine (TNF-α) production were assessed. Results: FARM had eccentric nucleus and plasma membrane ruffled with filopodial extensions. Ultrastructurally, numerous vesicular bodies presumed to be lysosomes were present. FARM treated with troglitazone, a selective PPAR γ agonist, had similar in vitro viability with untreated FARM. However, treated FARM co-cultured with polystyrene particles, internalized more particles with a mean volume density of 41 % compared to that of untreated FARM of 21 %. Further, treated FARM significantly decreased LPS-induced TNF-α production in a dose dependent manner. Conclusion: Results from this study show that PPAR γ synthetic ligands enhance phagocytic ability of FARM. Further the ligands attenuate production of proinflammatory cytokines in the FARM, suggesting potential therapeutic application of PPAR γ ligands in the management of respiratory inflammatory disorders in the poultry industry.
Acute and Sub-acute Oral Toxicity Profile of Root Bark Methanol Extract of Carissa Edulis Vahl
(Pharmacognosy Journal, 2023) Mbiri, Jane Wanja; Ogila, Kenneth; Kisangau, Patrick; Gicheru, Michael
Background: Carissa edulis is widely used in traditional medicine to manage numerous ailments. However, few studies have assessed its toxicity. Therefore, this study aimed to determine acute and sub-toxicity levels of C. edulis methanol extract. Methods: In the acute toxicity probe, a limit test was conducted whereby the extract was given as a solo dose by gavage. The rats were observed for two weeks. The observations included mortality and changes in the general appearance and behavior of the experimental animals. The body weights of the rats were taken weekly. For the sub-acute toxicity probe, the rats received the extract daily at dosages 300, 520, and 900 mg/kg by gavage for 28 days. Body weights were also taken weekly. On day twenty-nine, the weights of the rats were taken, the rats were sacrificed, and blood was collected for biochemical and hematological analysis. Body organs were harvested, and their weights were taken. Results: The results of the acute toxicity probe showed that the extract didn’t cause mortality or toxicity signs throughout the study duration. The LD50 of the extract was therefore deemed to be above 2,000 mg/kg. The sub-acute toxicity probe results demonstrated that the extract, at all the tested dosages, didn’t cause mortality or affect the rats’ organ weights, body weights, or hematological and biochemical parameters throughout the study duration. Conclusions: In conclusion, the methanol extract of C. edulis is not toxic since it didn’t cause mortality or toxicity signs in both acute and sub-acute toxicity probes.
Adjuvants in malaria vaccine development strategies: a review
(2016-04) Ogise, Josiah; Mumo, Ruth; Nyachieo, Atunga; Mutiso, Joshua; Kamau, Joseph; Onkoba, Nyamongo
Malaria leads in global rates of mortality and morbidity majorly borne by children aged below five years and primigravida women in developing countries. According to WHO, the cases of malaria infections in 2014 declined, despite cases of parasite resistance to available anti-malarial drugs and anopheline mosquitoes resistant to insecticides being reported. Therefore, there is need for an improved malaria control strategy including an effective malaria vaccine which can confer blood stage immunity and prevent development of clinical malaria. This venture has been explored for several decades resulting in discovery of promising antigen candidates but we lack appropriate adjuvants for human use capable of boosting immunogenicity of this antigens. In this review, we highlight limitations of various antigens in conjunction with adjuvants used and provide insight on new strategies of improving vaccine immunogenicity by incorporating immunomodulatory molecules and epitopes. Keywords: Malaria; adjuvants; immunogenicity; protection; vaccines; clinical trials
The African Green Monkey model for cutaneous and visceral leishmaniasis
(Trends in Parasitology, 2001-12) Gicheru, M. M.; Oloboa, Joseph O.; Anjilic, Chris O
Non-human primates are valuable models for biomedical research because of their similarities to human anatomy, immunology and physiology. Leishmaniasis, a disease caused by protozoan parasites, has a worldwide distribution and results in high morbidity and mortality. Availability of a non-human primate model of leishmaniasis would facilitate the study of different aspects of this disease and would accelerate the development of vaccines and new drugs. In this article, some interesting features of the vervet monkey (African Green monkey) model of human cutaneous and visceral leishmaniasis are discussed
The African Green Monkey Model for Cutaneous and Visceral Leishmaniasis.
(PubMed, 2001-12) Gicheru, M. M.; Olobo, J. O.; Anjili, C. O.
Non-human primates are valuable models for biomedical research because of their similarities to human anatomy, immunology and physiology. Leishmaniasis, a disease caused by protozoan parasites, has a worldwide distribution and results in high morbidity and mortality. Availability of a non-human primate model of leishmaniasis would facilitate the study of different aspects of this disease and would accelerate the development of vaccines and new drugs. In this article, some interesting features of the vervet monkey (African Green monkey) model of human cutaneous and visceral leishmaniasis are discussed.
Age‑specific Plasmodium parasite profile in pre and post ITN intervention period at a highland site in western Kenya
(BioMed Central, 2017) Ototo, Ednah N.; Zhou, Guofa; Kamau, Lucy; Mbugi, Jenard P.; Wanjala, Christine L.; Machani, Maxwell; Atieli, Harrysone; Githeko, Andrew K.; Yan, Guiyun
Background: Monitoring and evaluation of entomological, parasitological and clinical data is an important component of malaria control as it is a measure of the success of the interventions. In many studies, clinical data has been used to monitor trends in malaria morbidity and mortality. This study was conducted to demonstrate age dependent prevalence of malaria in the pre- and post-interventions period. Methods: A series of cross-sectional malaria parasitological surveys were conducted in Iguhu, western Kenya. Participants were randomly selected school-aged children between 6 and 13 years. The study was conducted between June 2002–December 2003 and January 2012–February 2015. Sexual and asexual parasite prevalence and densities were determined using microscopy. Age-dependence in parasite infections was compared between 2002–2003 and 2012–2015. Results: Plasmodium falciparum had the highest prevalence of 43.5 and 11.5% in the pre- and post-intervention periods. Plasmodium malariae had a prevalence of 2.3 and 0.2%, while Plasmodium ovale had a prevalence of 0.3 and 0.1% during the pre- and post-intervention period, respectively. There was a 73.7% reduction in prevalence of P. falciparum in the post-intervention compared to the pre-intervention period. Plasmodium falciparum parasite density increased by 71.2% between pre- and post-intervention period from (geometric mean of ) 554.4–949.2 parasites/μl. Geometric mean gametocytaemia in Iguhu was higher in the post-intervention period (106.4 parasites/μl), when compared to the pre-intervention period (54.1 parasites/μl). Prevalence and density of P. falciparum showed a lower age-dependency during post-intervention period when compared to pre-intervention period. Conclusion: The study provides evidence for reduction of malaria prevalence following the introduction of LLINs and ACT in western Kenya. Fewer people become infected but the few infected may be more infectious as suggested by higher gametocyte densities. The high parasite densities, which were not dependent on age, observed in the post intervention period imply that a more comprehensive integrated malaria management may be required to sustain the current interventions and hence reduce malaria transmission.
Airborne Volatiles from Melinis minutiflora P. Beauv., a Non-Host Plant of the Spotted Stem Borer
(Routledge Taylor & Francis Group, 2011-12-08) Hassanali, Ahmed; Pickett, J. A.; Khan, Z. R.; Lwande, W.; Chhabra, S. C.; Kimani, S. M.
Airborne volatiles released by Melinis minutiflora P. Beauv., a non-host plant of the spotted stem borer, Chilo partellus (Swinhoe), were trapped from the live plant by air entrainment into porous polymer Porapak Q and analyzed by GC and GC/MS. The main hydrocarbons identified and confirmed by co-injection with authentic samples on two columns of different polarities were (3E)-4,8-dimethylnona-1,3,7-triene (28.1% of isolated volatiles) and β-caryophyllene (24.2% of isolated votatiles). Of these, (3E)-4,8-dimethylnona-1,3,7-triene is electroantenographically active (EAG) against Chilo partellus (Swinhoe).
Alarming Cases of Cancer in Kenya: A Case for Meru and Tharaka Nithi Counties
(Society for Science and Education, 2023-01) Mutiso, Joshua; Gitonga, Ciriaka; Abdullahi, Bulle; Simbauni, Jemimah; Gicheru, Michael
Background: Cancer is one of the leading causes of morbidity and mortality worldwide. In Kenya, cancer as a disease ranks third as a cause of death after infectious and cardiovascular diseases and the cancer cases are increasing at an alarming rate. Objective: The current study was aimed at determining the prevalence trends of cancer in Meru and Tharaka Nithi Counties with an aim of putting proper infrastructural and human capacity development to combat cancer. Methods: A random selection of patients aged between five to eighty-two years clinically diagnosed as cancer patients who were visiting Meru and Chuka General Hospitals for a period of one year were recruited for the study. The participants were requested to give a verbal consent and respond to a brief questionnaire concerning their gender, age and the type of cancer they are suffering from. This study used retrogressive approach where the trend of cancer incidences and death rate were determined for the last eight years (2011 to 2018) using the hospital data. Data were analysed using statistical package for social sciences (SPSS). Results: This study established that the prevalence of cancer in people visiting hospitals in Meru and Tharaka Nithi Counties was 0.32% and 0.38% respectively. Further, the prevalence trends of cancer cases in the two counties have been increasing over the last eight years. Conclusion: The study concludes that cancer is prevalent in Meru and Tharaka Nithi Counties. It is therefore recommended that proper infrastructural and human capacity development be put in place to combat cancer.
Analyses of mitochondrial genes reveal two sympatric but genetically divergent lineages of Rhipicephalus appendiculatus in Kenya
(BioMed Central, 2016) Kanduma, E.G.; Mwacharo, J.M.; Githaka, N.W.; Kinyanjui, P.W.; Njuguna, J.N.; Kamau, L.C.; Kariuki, E.; Mwaura, S.; Skilton, R.A.; Bishop, R.P.
Background: The ixodid tick Rhipicephalus appendiculatus transmits the apicomplexan protozoan parasite Theileria parva, which causes East coast fever (ECF), the most economically important cattle disease in eastern and southern Africa. Recent analysis of micro- and minisatellite markers showed an absence of geographical and host-associated genetic sub-structuring amongst field populations of R. appendiculatus in Kenya. To assess further the phylogenetic relationships between field and laboratory R. appendiculatus tick isolates, this study examined sequence variations at two mitochondrial genes, cytochrome c oxidase subunit I (COI) and 12S ribosomal RNA (rRNA), and the nuclear encoded ribosomal internal transcribed spacer 2 (ITS2) of the rRNA gene, respectively. Results: The analysis of 332 COI sequences revealed 30 polymorphic sites, which defined 28 haplotypes that were separated into two distinct haplogroups (A and B). Inclusion of previously published haplotypes in our analysis revealed a high degree of phylogenetic complexity never reported before in haplogroup A. Neither haplogroup however, showed any clustering pattern related to either the geographical sampling location, the type of tick sampled (laboratory stocks vs field populations) or the mammalian host species. This finding was supported by the results obtained from the analysis of 12S rDNA sequences. Analysis of molecular variance (AMOVA) indicated that 90.8 % of the total genetic variation was explained by the two haplogroups, providing further support for their genetic divergence. These results were, however, not replicated by the nuclear transcribed ITS2 sequences likely because of recombination between the nuclear genomes maintaining a high level of genetic sequence conservation. Conclusions: COI and 12S rDNA are better markers than ITS2 for studying intraspecific diversity. Based on these genes, two major genetic groups of R. appendiculatus that have gone through a demographic expansion exist in Kenya. The two groups show no phylogeographic structure or correlation with the type of host species from which the ticks were collected, nor to the evolutionary and breeding history of the species. The two lineages may have a wide geographic distribution range in eastern and southern Africa. The findings of this study may have implications for the spread and control of R. appendiculatus, and indirectly, on the transmission dynamics of ECF
Analysis of genetic variability in Anopheles arabiensis and Anopheles gambiae using microsatellite loci
(WILEY, 2003-09-10) Orango, S.; Field, L. M.; James, A.; Kamau, L.; Mukabana, W. R.; Hawley, W. A.; Lehmann, T.; Irungu, L. W.; Collins, F. H.
We analysed genetic variability in Anopheles arabiensis and Anopheles gambiae populations using micro-satellite loci to determine whether the Rift Valley restricts the flow of genes. Deviations from Hardy–Weinberg expectations were significant, and were most likely to be due to the high frequency of null alleles observed. An. arabiensis populations occurring between 40 and 700 km apart across the Eastern arm of the Rift Valley were not differentiated (pair-wise Fst range: 0.0033–0.0265, P > 0.05). Neither were An. gambiae populations from Asembo Bay and Ghana (Fst: 0.0063, P > 0.05) despite a geographical separation of about 5000 km. In contrast, significant differentiation was observed between An. gambiae populations from Asembo Bay and Kilifi (about 700 km apart; FST= 0.1249, P < 0.01), suggesting the presence of a barrier to gene flow.
An analysis of haematological parameters in patients and individual residents of a Plasmodium falciparum malaria holoendemic area of western Kenya
(PubMed Central, 2001) Orago, A. S.; Wattimah, D.N.; Aloka, P.L.; Gitau, C.W.; Orago, M.A.; Onyango, T.G.
Many clinical symptoms of malaria are associated with alterations in certain haematological parameters during acute and subclinical infections. Total leucocyte and erythrocyte counts, haemoglobin concentration, haematocrit and other minor indices, were investigated in five cohort groups of individuals resident in a malaria hyperendemic area of western Kenya. The groups included age- and sex-matched adults with acute Plasmodium falciparum malaria, aparasitaemic adults, children with acute malaria, aparasitaemic children and asymptomatic-parasitaemic school children. The study aimed at defining what constitutes immunity to malaria which may be important in the critical evaluation of malaria vaccine antigens. Anaemia was more severe in adults and children with acute malaria than in their age- and sex-matched aparasitaemic and asymptomatic-aparasitaemic school children. Lymphocyte counts were significantly higher in asymptomatic-aparasitaemic school children than in aparasitaemic adults, suggesting a possible functional role for lymphocytes in the anti-disease immunity in the former group
Anopheles Gambiae: Historical Population decline Associated with Regional Distribution of insecticide-treated Bed Nets in Western Nyanza Province, Kenya.
(Malaria Journal, 2010-02) Mutuku, F. M.; Bayoh, M. N.; Mathias, D. K.; Odiere, M. R.; Kamau, L. M.; Gimnig, J. E.; Vulule, J. M.; Hawley, W. A.; Hamel, M. J.; Walker, E. D.
BACKGROUND: High coverage of insecticide-treated bed nets in Asembo and low coverage in Seme, two adjacent communities in western Nyanza Province, Kenya; followed by expanded coverage of bed nets in Seme, as the Kenya national malaria programme rolled out; provided a natural experiment for quantification of changes in relative abundance of two primary malaria vectors in this holoendemic region. Both belong to the Anopheles gambiae sensu lato (s.l.) species complex, namely A. gambiae sensu stricto (s.s.) and Anopheles arabiensis. Historically, the former species was proportionately dominant in indoor resting collections of females. METHODS: Data of the relative abundance of adult A. gambiae s.s. and A. arabiensis sampled from inside houses were obtained from the literature from 1970 to 2002 for sites west of Kisumu, Kenya, to the region of Asembo ca. 50 km from the city. A sampling transect was established from Asembo (where bed net use was high due to presence of a managed bed net distribution programme) eastward to Seme, where no bed net programme was in place. Adults of A. gambiae s.l. were sampled from inside houses along the transect from 2003 to 2009, as were larvae from nearby aquatic habitats, providing data over a nearly 40 year period of the relative abundance of the two species. Relative proportions of A. gambiae s.s. and A. arabiensis were determined for each stage by identifying species by the polymerase chain reaction method. Household bed net ownership was measured with surveys during mosquito collections. Data of blood host choice, parity rate, and infection rate for Plasmodium falciparum in A. gambiae s.s. and A. arabiensis were obtained for a sample from Asembo and Seme from 2005. RESULTS: Anopheles gambiae s.s. adult females from indoor collections predominated from 1970 to 1998 (ca. 85%). Beginning in 1999, A. gambiae s.s decreased proportionately relative to A. arabiensis, then precipitously declined to rarity coincident with increased bed net ownership as national bed net distribution programmes commenced in 2004 and 2006. By 2009, A. gambiae s.s. comprised proportionately ca. 1% of indoor collections and A. arabiensis 99%. In Seme compared to Asembo in 2003, proportionately more larvae were A. gambiae s.s., larval density was higher, and more larval habitats were occupied. As bed net use rose in Seme, the proportion of A. gambiae larvae declined as well. These trends continued to 2009. Parity and malaria infection rates were lower in both species in Asembo (high bed net use) compared to Seme (low bed net use), but host choice did not vary within species in both communities (predominantly cattle for A. arabiensis, humans for A. gambiae s.s.). CONCLUSIONS: A marked decline of the A. gambiae s.s. population occurred as household ownership of bed nets rose in a region of western Kenya over a 10 year period. The increased bed net coverage likely caused a mass effect on the composition of the A. gambiae s.l. species complex, resulting in the observed proportionate increase in A. arabiensis compared to its closely related sibling species, A. gambiae s.s. These observations are important in evaluating the process of regional malaria elimination, which requires sustained vector control as a primary intervention.
Anti-Proliferative Activities of Centella Asiatica Extracts on Human Respiratory Epithelial Cells in vitro
(Sociedad Chilena de Anatomía, 2013) Gicheru, M. M.; Mutua, P. M.; Makanya, A.N.; Kiama, S. G.
Centella asiatica or "pegaga" is well known for its ability in promoting wound healing. This study focused on the effect of Centella asiatica on the proliferation of human respiratory epithelial (RE) cells. RE cells were cultured using co-culture techniques until first passage (P1). Viability cell test by tryphan blue dye exclusion assay showed that there was high percentage of cell viability at both P0 (74%) and P1 (91.61%). Triplicate MTT assays were carried out with different concentrations of C. asiatica from 15.6 ppm, 31.3 ppm, 62.5 ppm, 125 ppm, 250 ppm, 500 ppm, 1000 ppm, until 2000 ppm. The higher the concentration of C. asiatica, the more inhibitory effect was seen. C. asiatica aqueous extract at concentration 1000 ppm and 2000 ppm demonstrated a significant (p<0.05) inhibitory effect on human RE cells proliferation on day 4 and day 7 after treatment. This provides potential use of C. asiatica extract for the treatment of conditions with respiratory epithelial cells overgrowth
Antiretroviral drugs toxicity and immune status of HIV patients under comprehensive care in Embu, Kenya
(2013-02) Gicheru, M. M.; Namu, John Samuel; Ng'ang'a, Z.
The objective of this study was to determine toxicity and immune status of HIV patients under ARVs (Zidovudine, Stavudine and Nevirapine) which comprises first line ARV combination regime currently being used in Kenya. A total of sixty (60) HIV patients participated in the study after consenting to undergo comprehensive care. A control group of forty (40) HIV patients on only contrimoxale (septrin), Analysis of Variance (ANOVA), t-test and correlation coeficientwere used to analyse the data. The results showed treatment with ARVs may cause. Based on the findings of this study it is recommended that the ARV drug combination used may be initiated for patients at baseline CD4 counts of 101-150 cells/μl of blood. However change to another ARV drug combination regime may be introduced after three months of use to minimize toxicity associated with prolonged use.
Assessment of Different Legumes for the Control of Striga hermonthica in Maize and Sorghum
(Madison, 2007-03) Hassanali, Ahmed; Khan, Z. R.; Midega, C. A.O.; Pickett, J. A.; Wadhams, L. J.
The witchweed, Striga hermonthica (Del.) Benth., is a major constraint to maize (Zea mays L.) and sorghum [Sorghum bicolor (L.) Moench] production in sub-Saharan Africa. Intercropping maize and sorghum with desmodium (Desmodium spp.) effectively controls Striga and enhances grain yields. Studies were thus conducted to assess the potential role of intercropping maize and sorghum with different food legumes for control of Striga Seasonal Striga counts in the intercrops, other than greenleaf desmodium where the counts consistently remained close to zero, were generally not significantly different from those in the control in both crops. A pooled analysis across seasons, however, showed that intercropping sorghum with cowpea [Vigna unguiculata (L.) Walp.], greengram [Vigna radiata (L.) Wilczek], and crotalaria (Crotalaria ochroleuca G. Don), and maize with crotalaria significantly reduced Striga populations. Within-season analysis showed that it was only the greenleaf desmodium intercrop that maintained significantly enhanced grain yields relative to the control. On the other hand, multiseason analysis showed that it was only the crotalaria, cowpea, and greenleaf desmodium intercrops in maize and greenleaf desmodium intercrop in sorghum that significantly enhanced grain yields. These results indicate that intercropping sorghum with cowpea, greengram, or crotalaria and maize with crotalaria could be combined with other cultural methods for a sustainable control of S. hermonthica
Association between Malnutrition and Immunoglobulin G Responses to Crude Asexual P. falciparum schizont Lysates in Children Attending Ishiara Hospital, Embu County, Kenya
(SCIENCEDOMAIN International, 2017) Mungiria, Juster; Gicheru, M. M.; Kavili, David; Mburu, David
Aim: The aim of this study was to determine levels of Plasmodium falciparum parasitaemia in children and relationship between IgG responses against the parasite and nutritional status of children. Study Design: Cross sectional study of children diagnosed positive for P. faciparum in Ishiara District Hospital, Embu county, Kenya was done between August 2011 and June 2012. Methodology: A total of 380 children, under 5 years who tested positive to P. faciparum infection were used for the study. Children with less than -2 Z score of height-for-age were classified as stunted and those with less than -2 Z score of weight-for-height were classified as wasted. Malnourished children were identified by the criteria of WHO. P. faciparum parasitaemia was determined by microscopy, using Giemsa stained thin and thick blood smears while the parasite`s IgG antibody responses were assessed by the Enzyme linked immune-sorbent assay. Results: Of the 380 children 70% were malnourished. Of the malnourished children 30% were stunted, 37% wasted while 3% were both stunted and wasted. Well-nourished children had mean parasitaemia of 530 per micro litre which was lower (P0,05). IgG responses of well nourished children (1.9) was higher than 1.2 of wasted children (r=0.7. P< 0.05) and also between the well-nourished and those both stunted and wasted (r = -0.8; P < 0.05). Conclusion: This study showed that malnutrition reduces IgG responses of children below 5 years to P. falciparum infection and predisposes them to malaria.
Association of Interferon-gamma Responses to Pre-erythrocytic Stage Vaccine Candidate Antigens of Plasmodium Falciparum in Young Kenyan Children with Improved Hemoglobin Levels: XV. Asembo Bay Cohort Project.
(The American Journal of Tropical Medicine and Hygiene, 2003-05) Ong'echa, J. M.; Lal, A. A.; Terlouw, D. J.; Ter Kuile, F. O.; Kariuki, S. K.; Udhayakumar, V.; Orago, A. S.; Hightower, A. W.; Nahlen, B. L.; Shi, Y. P..
Previous studies in animal models have revealed an association between interferon-gamma (IFN-gamma), produced by CD8+ T cells and irradiated sporozoite-induced sterile immunity. To determine whether IFN-gamma can serve as a marker of pre-erythrocytic protective immunity in individuals naturally exposed to malaria, we characterized IFN-gamma and lymphocyte proliferative responses to previously defined CD8+ cytotoxic T lymphocyte (CTL) epitopes from six pre-erythrocytic stage antigens in 107 children six months to two years old from a community-based birth cohort in western Kenya. We found that IFN-gamma positive responders had higher hemoglobin (Hb) levels and significantly reduced prevalence of severe malarial anemia one month after the test compared with IFN-gamma non-responders, suggesting that IFN-gamma immune responses to these pre-erythrocytic antigens were associated with protection against malarial anemia. Children who responded by lymphocyte proliferation had a significantly longer time to first documented malaria parasitemia after birth; however, there was no correlation between the presence of lymphocyte proliferative response and higher Hb levels. We propose that IFN-gamma production could be used as a potential marker of protective immunity against malaria associated anemia in young children living in malaria holoendemic areas.

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