Spatial-temporal distribution and sequence diversity of Group A human respiratory syncytial viruses in Kenya preceding the emergence of ON1 genotype

Background Human respiratory syncytial virus (HRSV) is a major cause of severe viral acute respiratory illness and contributes significantly to severe pneumonia cases in Africa. Little is known about its spatial–temporal distribution as defined by its genetic diversity. Methods A retrospective study conducted utilizing archived nasopharyngeal specimens from patients attending outpatient clinics in hospitals located in five demographically and climatically distinct regions of Kenya; Coast, Western, Highlands, Eastern and Nairobi. The viral total RNA was extracted and tested using multiplex real time RT-PCR (reverse transcriptase polymerase chain reaction). A segment of the G-gene was amplified using one-step RT-PCR and sequenced by Sanger di-deoxy method. Bayesian analysis of phylogeny was utilized and subsequently median joining methods for haplotype network reconstruction. Results Three genotypes of HRSVA were detected; GA5 (14.0%), GA2 (33.1%), and NA1 (52.9%). HRSVA prevalence varied by location from 33% to 13.2% in the Highlands and the Eastern regions respectively. The mean nucleotide diversity (Pi[π]) varied by genotype: highest of 0.018 for GA5 and lowest of 0.005 for NA1. A total of 58 haplotypes were identified (GA5 10; GA2 20; NA1 28). These haplotypes were introduced into the population locally by single haplotypes and additional subsidiary seeds amongst the GA2 and the NA1 haplotypes. Conclusions HRSVA was found across all the regions throughout the study period and comprised three genotypes; GA5, GA2, and NA1 genotypes. The genotypes were disproportionately distributed across the regions with GA5 gradually increasing toward the Western zones and decreasing toward the Eastern zones of the country

A Competitive Enzyme Linked Immunosorbent Assay For The Determination Of Diminazene Residues In Animal Tissues

The importance of ensuring food safety through the reduction of chemical residues in our food supply cannot be overemphasized. Food safety remains a major challenge confronting contemporary society. To ensure wholesomeness of food of animal origin, the level of drug residues must be below the maximum residue limits (MRLs) set by World Health Organization (WHO) and Food and Agriculture Organization (FAO). This calls for cost effective and efficient analytical methods for both quality assurance and monitoring. Diminazene aceturate is one of the few treatment drugs for animal trypanosomosis in the market. Because of its wide use in food producing animals, unwanted residues may be a risk to consumers. A competitive enzyme-linked immunosorbent assay (cELISA) for determination of diminazene residues in edible animal tissues after extraction in 0.1 M borax pH 9.7 is described. The assay has advantages of speed, high throughput and lower cost of analysis compared to the other conventional methods. The assay uses rabbit anti-diminazene polyclonal antibodies bound on a 96-well microtiter plate. Horseradish peroxidase-labeled diminazene and diminazene in a test sample were allowed to compete overnight at 4° C for the limited number of antibodies bound on the microtiter plate. After six washes with buffer, enzyme activity was determined by adding tetramethyl-benzidine and hydrogen peroxide as substrate. The assay detection limits for diminazene were 2.4 ng/g in muscle, 2.5 ng/g in liver and 2.2 ng/g in kidney while limits of quantification were 7.2 ng/g, 7.5 ng/g and 6.6 ng/g respectively. The recoveries for muscle liver and kidney spiked with 5 ng/g were 78%, 77% and 80% respectively while for 1,000 ng/g were 74%, 76.% and 84% respectively. The within-and between assay coefficients of variation (CV) were 2.4% and 15.5% respectively while assay specificity was above 99.9%. It is concluded that as a result of the good recoveries, high specificity and repeatability, the method could be used in the determination and monitoring of diminazene residues in tissues. These activities aimed at ensuring the safety of food of animal origin could play a major role in enhancing consumer confidence in these products which are very essential for health

In vivo activity of selected medicinal plants in Kenya against Trypanosoma evansi.

Chloroform extracts from two Kenyan medicinal plants (Azadirachta indica/ neem leaves, 500 mg/ kg, 250mg/kg and 125mg/kg and Physalis peruviana 1000mg/kg, 500mg /kg and 250mg/kg body weights) were analysed in vivo for trypanocidal activity against Trypanosoma evansi. Experimental mice were injected with T. evansi KETRI 2450 and the drugs administered intraperitoneally at the onset of parasitaemia. Treated animals were then monitored for parasitaemia starting the following day after treatment.In comparison to suramin, the standard drug, extract of both A. indica leaves and P. peruviana were observed to express trypanocidal activity better than standard drug. High activity was found for extract of A. indica leaves (500mg/kg body weight) which completely cleared the parasites from infected mice by 24 days post treatment. Following this observation, it is recommended that future studies should address purification, structure eluci dation and biochemical characteristic of active components of Azadirachta indica leaves. This study has confirmed the hypothesis that some plants used in control of trypanosomiasis in Kenya have trypnocidal potential.Keywords: African trypanosomosis, Medicinal Plants, Anti-trypanosomal activity, In vivo model

Assessment of Bacteriological and Physico-chemical Qualities of Stand-pipe Drinking Water Stored in Huruma Food Kiosks of

A total of 104 water samples were randomly taken and analyzed to determine bacteriological and physico-chemical qualities of stand-pipe drinking water stored in Huruma food kiosks of Nairobi, Kenya. Out of these, 92 were from storage containers and 12 from stand-pipes supplying the food kiosks. The mean sample temperature ranged from 19.19°C to 23.0ºC, while the mean pH ranged from 6.75 to 7.0. All samples analyzed in this study had a residual chlorine level of 0.5 mg/l. The mean total bacterial count (TBC) for stand-pipe samples was 46 per ml, while that from stored water was 615 per ml. The mean coliform count was 7 and 64 per 100 ml for stand-pipes and stored water respectively. Faecal streptococci had mean counts of 13 and 55 per ml in stand-pipes and stored water respectively. Feacal coliforms were isolated from 2 (17%) stand-pipes and 43 (47%) stored water. Faecal streptococci was isolated from 2 (17%) and 57 (62%) stand-pipes and stored water samples respectively. A significant difference in TBC between stand-pipe and stored water (t = -4.379, df = 102, p = 0.001) was noted. Questionnaire and observation investigations revealed that 82(90%) of Kiosk workers treated their drinking water on request. Some water scooping vessels were found lying on dirty floor outside and near open drainage systems. In conclusions results from this study indicates a high risk of infections with pathogens to the consumers. It is therefore recommended that drinking water be treated before consumption. Kenya Veterinarian Vol. 31 (1) 2007: pp. 26-3

COMBINATION OF BLEACH AND FLOURESCENT MICROSCOPY: A MILESTONE IN THE DIAGNOSIS OF SMEAR NEGATIVE TUBERCULOSIS

ABSTRACTBackground: The reliability of direct smear microscopy for diagnosis of tuberculosis has frequentlybeen questioned due to low sensitivity. Treatment of sputum with sodium hypochlorite (NaOCI)has been used to increase sensitivity in many settings. However, no study has established the effectof NaOCI on fl uorescent microscopy.Objective: To establish whether NaOCI concentration method enhances positivity of fl uorescentmicroscopy smear negative sputum for diagnosis of tuberculosis.Design: A prospective study.Setting: Mbagathi District Hospital and Centre for Respiratory Diseases Research, Kenya MedicalResearch Institute.Results: Forty fi ve (22%) specimens were culture positive. Fluorescent microscopy sensitivitywas 28.9% and 22.2% after centrifugation and sedimentation with 3.5% NaOCI, respectively (P >0.05). Sensitivity was 24.4% and 17.8% after centrifugation and sedimentation with 5% NaOCI,respectively (P > 0.05). Although there was no statistical signifi cance difference between the twoNaOCI concentration methods, 3.5% NaOCI with centrifugation indicated a higher yield.Conclusion: Use of NaOCI signifi cantly enhances positivity of smear negative sputum for diagnosisof tuberculosis when used with fl uorescent microscopy. This approach could be recommendedfor screening all tuberculosis suspects especially in settings with potential smear negativetuberculosis