Prevalence and intensity of urinary schistosomiasis and soil-transmitted helminths among women of reproductive age in Mwaluphamba,Kwale

Objective:To assess the epidemiology of urinary schistosomiasis and soil-transmitted helminthiasis among women of reproductive age in Mwaluphamba,Kwale County,Kenya.Methods:A community-based cross-sectional study design was employed to randomly sample 422 women of reproductive age(15-<50 years)from four villages in Mwaluphamba location.Stool specimens were collected and examined using the Kato-Katz method,while filtration technique was used to analyze urine specimens.Participants’sociodemographic details were obtained using a standardized questionnaire.Results:Urinary schistosomiasis prevalence was at 4.7%(20/422,95%CI 2.8%-6.9%)while the prevalence of soil-transmitted helminthiasis infection was 4.5%(19/422,95%CI 2.6%-6.7%).The infection intensities of urinary schistosomiasis among the study participants ranged from 1 to 120 eggs/10 mL of urine with median egg count of 18.45 eggs/10 mL.The patients were diagnosed with light infection,of 56.16 egg/gram and 48.48 egg/gram for Trichuris trichiura and hookworms,respectively.Women without latrines had 15.7 times higher risk of having urinary schistosomiasis compared to those with a latrine.Similarly,use of surface water(aOR=1.0,95%CI 0.2-1.4,P=0.010)and crossing the river to go to a place(aOR=1.1,95%CI 0.3-1.6,P=0.009)were statistically significant risk factors for getting urinary schistosomiasis.In bivariable regression analysis,defecating around the water source(OR=4.3,95%CI 1.5-12.9)had a statistically significant association with the prevalence of soil-transmitted helminthiasis(P=0.008).Conclusions:This study has given an insight on the prevalence and intensity of urinary schistosomiasis and soil-transmitted helminthiasis in Mwaluphamba location that form a basis for strengthening the control and elimination programmes for these neglected tropical diseases.

Human Bocavirus Infection in Children with Acute Respiratory Infection in Nairobi, Kenya

Background: Acute respiratory infection (ARI) is a leading cause of morbidity and mortality in children under five years of age in developing countries with viruses contributing significantly to this problem. The recently identified parvovirus, Human Bocavirus (HBoV), has also been associated with ARI. Objective: To determine the frequency of HBoV in patients with ARI. Materials and Methods: Samples from 125 consenting patients with influenza like illness signs and symptoms were collected. DNA was extracted from these samples using the QIAamp DNA blood mini kit (Qiagen, Germany). Conventional PCR was carried out and the amplicons were examined in 2% agarose gels stained with ethidium bromide. This was followed by sequencing of the HBoV positive samples. Results: Twenty one (16.8%) patients were found to have HBoV infection. Males (n = 61.9%) were mainly infected with HBoV. Local HBoV strains had 98.9% - 100% similarities and were found to cluster together with other strains obtained elsewhere. Conclusion: These findings suggest that HBoV plays a role in respiratory tract infections in children in Kenya just like it has been found elsewhere. It also sheds light on multiple infections associated with HBoV infections in Kenya.

Determinants of Persistent Sputum Smear Positivity after Intensive Phase Chemotherapy among Patients with Tuberculosis at Rhodes Chest Clinic, Nairobi, Kenya

The prevalence of TB in sub-Sahara Africa has been reported as 511 per 100,000 populations and a mortality of 74 per 100,000 in year 2009. In the same period, incidence was estimated at 350 cases per 100,000. In this regard, the health system requires strengthening to respond to the rising cases of infection, drug resistance and quality of life lost while continuing to seek interventions that improve adherence to medication and case detection among those infected. Methods: This study sought to determine factors that are associated with sputum positivity after intensive phase of chemotherapy in people with tuberculosis. It was a retrospective case-control study conducted in Rhodes chest clinic, a City Council health unit in Nairobi that specializes in treatment of chest infections. The participants were sampled from clinic attendants who had completed two months of intensive phase TB chemotherapy and met inclusion criteria. Results: Seventy participants of whom 25 (36%) were sputum positive at the end of two (2) months intensive phase were included in the study. Skipping medication doses was significantly associated with sputum positivity (p = 0.01). Patients who were sputum positive at the end of the two-month period were more likely to have taken longer time before seeking treatment compared to those who were sputum negative by median (IQR) 8 (3 - 12) and 4 (3 - 8) weeks respectively although this difference was not significant (p = 0.09). Patients who had not disclosed their infection status had a two-fold possibility of remaining sputum positive at the end of intensive phase. Conclusion: Early diagnosis and treatment of TB, and adherence to medication were important factors that affect sputum conversion during intensive phase of TB treatment. Therefore, public health practitioners should advise patients to seek prompt diagnosis and treatment of signs and symptoms of tuberculosis.

Prevalence, Incidence and Risk Factors for Acquisition of Herpes Simplex Virus Type 2 among Fishermen on the Shores of Lake Victoria in Kisumu County, Kenya

Background: Herpes simplex virus Type 2 (HSV-2) has been associated with HIV infection. More recently, HSV-2 incidence has been linked to HIV acquisition. A few studies have suggested that the fishing communities have a high HSV-2 prevalence but there is limited knowledge on HSV-2 incidence and associated risk factors among fishermen. Methods: Three hundred fishermen were consented, and evaluated for baseline HSV-2 serology status and again after 12 months among those negative at baseline. Sexual behavior and socio-demographic data were collected at enrolment and exit visits using a structured questionnaire. Baseline HIV serology and Human papillomavirus (HPV) DNA genotyping were also performed. Multivariate logistic regression was used to determine independent factors associated with HSV-2 acquisition. Results: Baseline HSV-2 prevalence was 56.3% (95% CI: 50.7 - 62.0). Factors associated with HSV-2 prevalence were, older age (aOR = 1.96;95% CI: 1.16 - 2.85), history of STI (aOR 2.12;95% CI: 1.19 - 3.91), infection with HIV (aOR 2.22;95% CI: 1.17 - 4.22), ever married (aOR = 3.80;95% CI: 1.42 - 11.90), most recent sexual act with sex worker/casual partner (OR= 3.56;95% CI: 1.49 - 8.62) and inconsistent condom use with new sexual partner (aOR = 6.34;95% CI: 2.24 - 13.04). The HSV-2 incidence was 23.6 (95% CI = 15.4 - 31.8)/100 pyr. Infection with persistent high-risk (HR) HPV (aIRR = 3.35;95% CI: 1.21 - 11.37), multiple (≥2) partners in 12 months prior to study participation (aIRR = 4.77;95% CI: 1.12 - 11.38), inconsistent condom use with new partner (aIRR =2.53;95% CI: 1.12 - 7.38) and most recent sexual act with sex worker/casual partner (OR = 3.03;95% CI: 1.17 - 8.58) were independent risk factors for HSV-2 acquisition. Conclusion: The incidence of HSV-2 is very high among fishermen. It is associated with persistent HR HPV infection and high-risk sexual behavior. Intervention strategies targeting these men with high risk sexual behavior are urgently needed to stop new HSV-2 acquisition and subsequently prevent HIV infection.

Prevalence and Incidence of HIV Infection among Fishermen along Lake Victoria Beaches in Kisumu County, Kenya

Background: Herpes simplex virus type-2 (HSV-2) and human papillomavirus (HPV) are common sexually transmitted infections (STIs) among fishing communities and are associated with high HIV prevalence in this underserved population. However, there is limited knowledge on HIV incidence among fishermen. This study aimed at determining prevalence, incidence and risk factors associated with HIV infection among fishermen in Kisumu Kenya. Methods: Three hundred fishermen were evaluated for baseline HIV, HSV-2, HPV infection and a structured questionnaire administered. HIV incidence was assessed after 12 months among those initially HIV negative. HIV incidence rate in person-years and prevalence were estimated. Multivariate logistic regression was used to determine factors independently associated with HIV acquisition. Results: HIV prevalence was 23.3% (95% CI: 18.5 - 28.1). Risk factors for baseline HIV prevalence were older age (aOR = 2.13;95% CI: 1.25 - 5.07), history of STI (aOR 4.21;95% CI: 2.07 - 9.34), baseline HPV infection (aOR 2.13;95% CI: 1.05 - 4.77), number of lifetime sexual partners (>5) aOR = 5.76 (95% CI: 1.41 - 13.57) and transactional sex (aOR = 10.98;95% CI: 1.86 - 19.34). Condom uses with new sexual partner (aOR 0.21, 95% CI: 0.08 - 0.55) and during most recent sexual act (aOR 0.09, 95% CI: 0.03 - 0.61), were negatively associated with HIV prevalence. HIV incidence was 4.2 (95% CI = 1.3 - 7.1) per 100 person-years with being single (aIRR = 8.32;95% CI: 1.27 - 54.67) as an independent risk factor. Condom use with new sexual partner (aIRR = 0.11;95% CI: 0.01 - 0.89) and recent sex with wife/regular girlfriend (compared to sex worker/casual partner;aIRR = 0.03;95% CI: 0.01 - 0.35) were associated with reduced risk of HIV acquisition. Conclusion: Inconsistent condom use and transactional/casual sexual partnerships were the main high-risk sexual behaviors in addition to marital status explaining the high HIV acquisition rate among fishermen. Intensified safer sex promotion is urgently needed in this subpopulation to avert new HIV infections.

利用SAS中非线性混和效应模型分析城市中阿拉伯按蚊水体滋生环境的时空变异系数

目前对于时间序列分析中出现的空间自相关现象，已经有很多的的文献详述了如何对这种现象进行识别与建模分析。但是，对于撒哈拉以南非洲地区疟疾的主要媒介-阿拉伯按蚊幼虫滋生地的地理空间相关性方面的研究还没研究报道。在空间回归分析中，空间相关性主要通过空间滤波方法完成，该滤波方法通过分析时间序列中随机误差的分布特征。运用基于地理连接矩阵的非参数特征向量分解空间滤波方法，以寻求能鉴别阿拉伯按蚊幼虫滋生水生环境的预测因子。首先，选择肯尼亚的两个城市，Kisumu和Malindi，进行了蚊虫滋生水体的现场采样工作。然后获取快鸟（QuickBird）卫星数据；并利用该数据对冈比亚按蚊的滋生水体进行遥感影像分析。把这些水体的地理空间信息数据输入SAS／GIS模型中，进行单因素分析、相关分析、数据分布分析、以及全局空间自相关统计。然后，利用空间协方差参数生成局部空间自相关指数（如：Moran’s指数）。并由该模型生成了选择性特征向量的粗子集，此粗子集可以被用来研究这些样方变量间的空间互作效应。最后，利用贝叶斯系数估计法定义矩阵中各参数的期望先验参数值，得知水体环境的深度是决定该水体能否滋生阿拉伯按蚊的关键预测性因素，并且深度与其滋生可能性呈明显的正相关关系；由转移空间连接矩阵生成的特征向量的特殊子集可以获知由阿拉伯按蚊水生环境预测因子以及所建立的空间回归模型中空间误差的相关性。

The Potential of DNA Barcode-Based Delineation Using Seven Putative Candidate Loci of the Plastid Region in Inferring Molecular Diversity of Cowpea at Sub-Species Level

The novelty and suitability of the mitochondrial gene CO1 in DNA barcoding as a reliable identification tool in animal species are undisputed. This is attributed to its standardized sequencing segment of the mitochondrial cytochrome c oxidase-1 gene (CO1) which has the necessary universality and variability making it a generally acceptable barcode region. CO1 is a haploid single locus that is uniparentally-inherited. Protein-coding regions are present in high-copy numbers making it an ideal barcode. The mitochondrial oxidase subunit I (COI) gene is a robust barcode with a suitable threshold for delineating animals and is not subject to drastic length variation, frequent mononucleotide repeats or microinversions. However, a low nucleotide substitution rate of plant mitochondrial genome [mtDNA] precludes the use of CO1 as a universal plant DNA barcode and makes the search for alternative barcode regions necessary. Currently, there exists no universal barcode for plants. The plastid region reveals leading candidate loci as appropriate DNA barcodes yet to be explored in biodiversity studies in Kenya. Four of these plastid regions are portions of coding genes (matK, rbcL, rpoB, and rpoC1), and three noncoding spacers (atpF-atpH, trnH-psbA, and psbK-psbL) which emerge as ideal candidate DNA loci. While different research groups propose various combinations of these loci, there exists no consensus;the lack thereof impedes progress in getting a suitable universal DNA barcode. Little research has attempted to investigate and document the applicability and extend of effectiveness of different DNA regions as barcodes to delineate cowpea at subspecies level. In this study we sought to test feasibility of the seven putative candidate DNA loci singly and in combination in order to establish a suitable single and multi-locus barcode regions that can have universal application in delineating diverse phylogeographic groups of closely related Kenyan cowpea variants. In this study, our focus was based on genetic parameters including analyses of intra- and infra-specific genetic divergence based on intra- and infra-specific K2P distances;calculation of Wilcoxon signed rank tests of intra-specific divergence among loci and coalescence analyses to delineate independent genetic clusters. Knowledge of DNA candidate loci that are informative will reveal the suitability of DNA barcoding as a tool in biodiversity studies. Results of this study indicate that: matK, trnH-psbA, psbK-psbL, and rbcL are good barcodes for delineating intra and infraspecific distances at single loci level. However, among the combinations, matK + trnH-psbA, rpoB + atpF-atpH + matK are the best barcodes in delineating cowpea subvariants. rbcL gene can be a suitable barcode marker at single locus level, but overall, multi locus approach appears more informative than single locus approach. The present study hopes to immensely contribute to the scanty body of knowledge on the novelty of DNA barcoding in cataloguing closely related cowpea variants at molecular level and hopes to open up future research on genomics and the possibility of use of conserved regions within DNA in inferring phylogenetic relationships among Kenyan cowpea variants.

肯尼亚、内罗毕涂阳肺结核的漏诊

背景:肯尼亚,内罗毕市委员会胸科诊所。 目的:为确定痰涂片漏读是造成肯尼亚内罗毕涂阴结核病不相称增加的因素。 方法:对1997年10月至1998年11月之间履行地方规划规定的认为是涂阴肺结核的病人,进一步收取两个痰标本,在研究实验室进行萤光显微镜检查。 结果:在选入研究的163名成人病例中,55％为人类免疫缺陷病毒1型(HIV-1)血清学阳性,100名病人在收集和获得两次新的痰标本在研究实验室再检查之前,已有两个研究前的痰涂片检查。在这些人中,19名(19％)通过再次检查为痰涂片阳性和第二次再检查又有7名(7％)成为涂片阳性。 结论:由地方规划确定的认为是涂阴肺结核的病人中当仔细地两次重复痰涂片检查时有26％为涂片阳性,提示,在涂阴结核病中有高比例的漏读,这可能是由于结棱病负担太重而导致痰检查的过于迅速和欠精确。对固定技术人员的再培训和培训更多的技术人员可能减少漏读和增加涂阳结核病的检出。该发现也强调需要常规的质量保证。

人类免疫缺陷病毒1型对结核病传染性的影响

背景:发展中国家三级转诊医院及其服务社区。目的:确定染有人类免疫缺陷病毒1型(HIV-1)的、经培养证实的肺结核病人的传染性。设计:HIV-1阳性和阴性的肺结核病例的家庭内接触者中结核病发病率和结核菌素皮肤试验阳性率的比较。结果:在255名HIV-1阴性索引病例(index case)的接触者中,2名为HIV-1阳性,在102名HIV-1阳性索引病例的接触者中,14名为HIV-1阳性(让步比[odds ratio,OR,一个事件发生的概率对其不发生的概率之比。译注。]=20.0,95％置信区间(CI)4.4—193),接触者中共诊断结核病21例,其中3例为HIV-1阳性。患结核病的HIV-1阳性索引病例接触者与HIV-1阴性索引病例接触者相比,总的未经校正的OR为1.6(95％CI0.6—4.3)。单独在HIV-1阴性接触者中,OR为1.5(95％CI0.4—4.4)。在该组中,接触者中结核病的最佳预报者是索引病例中的女性(OR=3.4,95％CI1.1—12),与索引病例同睡一床者(OR=2.6,95％CI0.9—1.4),和接触者年龄小于5岁者(OR=3.3,95％CI1.1—9.5),HIV-1阳性接触者比HIV-1阴性接触者更容易发生结核病(OR=4.1,95％CI0.7—17),HIV-1阳性和阴性索引病例的HIV-1阴性接触者的结核素皮肤试验阳性率相同(OR=1.1,95％CI0.7—1.6)。结论:与HIV-1联合的肺结核并不比单独患结核病的传染性强。社区中有了HIV-1。

Impact of single annual treatment and four-monthly treatment for hookworm and Ascaris lumbricoides,and factors associated with residual infection among Kenyan school children

Background:School-based deworming is widely implemented in various countries to reduce the burden of soil-transmitted helminths(STHs),however,the frequency of drug administration varies in different settings.In this study,we compared the impact of a single annual treatment and 4-monthly treatment over a follow-up among Kenyan school children,and investigated the factors associated with residual infection.Methods:We performed a secondary analysis of data from a randomized trial investigating whether deworming for STHs alters risk of acquiring malaria.Children received either a single treatment or 4-monthly albendazole treatments were followed longitudinally from February 2014 to October 2014.The relative impact of treatment and factors associated with residual infections were investigated using mixed-effects regression models.Predisposition to infection was assessed based on Spearman’s rank and Kendall’s Tau correlation coefficients.Results:In the 4-monthly treatment group,the proportion of children infected with hookworm decreased from 59.9 to 5.7%,while Ascaris lumbricoides infections dropped from 55.7 to 6.2%.In the single treatment group,hookworm infections decreased over the same time period from 58.7 to 18.3%(12.6%absolute difference in reduction,95%CI:8.9-16.3%),and A.lumbricoides from 56.7 to 23.3%(17.1%absolute difference in reduction,95%CI:13.1-21.1%).There was strong evidence for predisposition to both STH types.Residual hookworm infection among children on 4-monthly treatment were associated with male sex and baseline nutritional status,whereas A.lumbricoides infection was associated with individual and school-level infection at baseline,latrine cleanliness at schools.Conclusions:This study found that 4-monthly treatment w more effective than single annual treatment.Repeated treatments led to dramatic reductions in the intensities of STHs,but did not completely clear infections among school children in Kenya,a presumed reflection of reinfection in a setting where there is ongoing transmission.