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Emerging Infectious Diseases | 2012

Rickettsia felis Infection in Febrile Patients, Western Kenya, 2007–2010

Alice N. Maina; Darryn L. Knobel; Ju Jiang; Jo E. B. Halliday; Daniel R. Feikin; Sarah Cleaveland; Zipporah Ng’ang’a; Muthoni Junghae; Robert F. Breiman; Allen L. Richards; M. Kariuki Njenga

To determine previous exposure and incidence of rickettsial infections in western Kenya during 2007–2010, we conducted hospital-based surveillance. Antibodies against rickettsiae were detected in 57.4% of previously collected serum samples. In a 2008–2010 prospective study, Rickettsia felis DNA was 2.2× more likely to be detected in febrile than in afebrile persons.


Emerging Infectious Diseases | 2015

High Seroprevalence of Antibodies against Spotted Fever and Scrub Typhus Bacteria in Patients with Febrile Illness, Kenya

Jacqueline W. Thiga; Beth Mutai; Wurapa K. Eyako; Zipporah Ng’ang’a; Ju Jiang; Allen L. Richards; John N. Waitumbi

Serum samples from patients in Kenya with febrile illnesses were screened for antibodies against bacteria that cause spotted fever, typhus, and scrub typhus. Seroprevalence was 10% for spotted fever group, <1% for typhus group, and 5% for scrub typhus group. Results should help clinicians expand their list of differential diagnoses for undifferentiated fevers.


BMC Infectious Diseases | 2013

HIV-1 drug resistance-associated mutations among HIV-1 infected drug-naïve antenatal clinic attendees in rural Kenya

Michael Kiptoo; James Brooks; Raphael W. Lihana; Paul Sandstrom; Zipporah Ng’ang’a; Joyceline Kinyua; Nancy Lagat; Fredrick A. Okoth; Elijah M. Songok

BackgroundAccess to antiretroviral therapy (ART) has increased dramatically in Sub-Saharan Africa. In Kenya, 560,000 people had access to ART by the end of 2011. This scaling up of ART has raised challenges to the Kenyan health system due to emergence of drug resistant viruses among those on treatment and possible onward transmission. To counter this, and come up with an effective treatment strategy, it has become vital to determine baseline mutations associated with drug resistance among the circulating strains of HIV-1in Kenya.MethodsThe prevalence of mutations associated with drug resistance in HIV-1 protease (PR) and reverse transcriptase (RT) regions from 188 HIV-1 infected treatment-naïve pregnant women was investigated in Kapsabet, Nandi Hills and Kitale district hospitals of Kenya. Blood samples were collected between April 2005 and June 2006. The HIV-1 pol gene was amplified using primers for HIV-1 PR and RT and sequenced using the BigDye chemistry. The mutations were analyzed based on the IAS algorithm as well as the Stanford University HIV Drug Resistance Database.ResultsBased on the PR and RT sequences, HIV-1 subtypes A1 (n=117, 62.2%), A2 (n=2, 1.1%), D (n=27, 14.4%), C (n=13, 6.9%), G (n=3, 1.6%), and possible recombinants (n=26, 13.8%) were detected. Mutations associated with nucleoside reverse transcriptase inhibitors (NRTI) and non-nucleoside RTI (NNRTI)-resistance were detected in 1.6% (3 of 188) and 1.1% (2 of 188), respectively. Mutations associated with PI resistance were detected in 0.5% (1 of 188) of the study population.ConclusionThe prevalence of drug resistance among drug-naïve pregnant women in rural North Rift, Kenya in 2006 was 3.2%. Major drug resistance mutations associated with PIs, NRTIs and NNRTIs do exist among treatment-naïve pregnant women in North Rift, Kenya. There is a need for consistent follow-up of drug-naïve individuals in this region to determine the impact of mutations on treatment outcomes.


The Pan African medical journal | 2016

Factors associated with adequate weekly reporting for disease surveillance data among health facilities in Nairobi County, Kenya, 2013

Athman Juma Mwatondo; Zipporah Ng’ang’a; Caroline Wanjiku Maina; Lindah Makayotto; Moses Mwangi; Ian Njeru; Wences Arvelo

Introduction Kenya adopted the Integrated Disease Surveillance and Response (IDSR) strategy in 1998 to strengthen disease surveillance and epidemic response. However, the goal of weekly surveillance reporting among health facilities has not been achieved. We conducted a cross-sectional study to determine the prevalence of adequate reporting and factors associated with IDSR reporting among health facilities in one Kenyan County. Methods Health facilities (public and private) were enrolled using stratified random sampling from 348 facilities prioritized for routine surveillance reporting. Adequately-reporting facilities were defined as those which submitted >10 weekly reports during a twelve-week period and a poor reporting facilities were those which submitted <10 weekly reports. Multivariate logistic regression with backward selection was used to identify risk factors associated with adequate reporting. Results From September 2 through November 30, 2013, we enrolled 175 health facilities; 130(74%) were private and 45(26%) were public. Of the 175 health facilities, 77 (44%) facilities classified as adequate reporting and 98 (56%) were reporting poorly. Multivariate analysis identified three factors to be independently associated with weekly adequate reporting: having weekly reporting forms at visit (AOR19, 95% CI: 6-65], having posters showing IDSR functions (AOR8, 95% CI: 2-12) and having a designated surveillance focal person (AOR7, 95% CI: 2-20). Conclusion The majority of health facilities in Nairobi County were reporting poorly to IDSR and we recommend that the Ministry of Health provide all health facilities in Nairobi County with weekly reporting tools and offer specific trainings on IDSR which will help designate a focal surveillance person.


The Pan African medical journal | 2017

Sero-prevalence for Hepatitis B virus among pregnant women attending antenatal clinic in Juba Teaching Hospital, Republic of South Sudan

Anthony Laku Stephen Kirbak; Zipporah Ng’ang’a; Jared Omolo; Hakim Idris; Abdulmumini Usman; William Baguma Mbabazi

Introduction Hepatitis B virus infection is a major public health problem worldwide and in Africa. This would be the first ever documented study on epidemiology of Hepatitis B infections in the newly formed Republic of South Sudan. This study was designed to estimate the sero-prevalence of Hepatitis B virus infection amongst pregnant women attending antenatal services in Juba. Methods A cross-sectional study was conducted among pregnant women attending antenatal clinic services in Juba Teaching Hospital, in the period between December 2012 and March 2013. Any pregnant woman, attending antenatal care services at Juba Teaching Hospital, was included if she was a resident of Juba County for at least 1 year before pregnancy. A Hepatitis B case was defined as any women participating in the study and was found to be positive for HbsAg and confirmed by ELISA. Results This study documented that the prevalence of Hepatitis B surface antigen (HBsAg) among pregnant women attending ANC in Juba was 11% (31 out of the 280 samples). Other samples tested were indeterminate (36%), naturally immune (27.1%), susceptible (23%) and the remaining 1.8% was immune due to vaccination. Significant risk factors for Hepatitis B infection were loss of partner (OR 4.4 and CI of 1.4-13.9) and history of Jaundice (OR 1.7 and CI of 1.2-2.1). Conclusion These study findings show that only 29% of infants in Juba county are born to immune mothers (naturally or vaccine induced). The remaining 70% of babies would be at risk of infection, if a birth dose of Hepatitis B is not provided. We therefore recommended introduction of Hepatitis B Vaccine birth dose into routine infants’ vaccination series to eliminate this risk.


The Pan African medical journal | 2016

Prevalence, awareness and risk factors associated with Hepatitis B infection among pregnant women attending the antenatal clinic at Mbagathi District Hospital in Nairobi, Kenya

Jacqueline Asundula Malungu Ngaira; James Kimotho; Isaac Mirigi; Saida Osman; Zipporah Ng’ang’a; Raphael Lwembe; Missiani Ochwoto

Introduction Hepatitis B Viral Infection (HBV) remains one of the leading cause of morbidity and mortality globally accounting for 38-53% of chronic liver diseases and about 686,000 deaths annually. The prevalence of HBV is 9-20% in Sub-Saharan Africa, and in Kenya it is 5-30% among the general population and 9.4% among pregnant women. This study was aimed at identifying the prevalence, awareness and risk factors associated with HBV infections among pregnant women attending Antenatal clinic (ANC) at Mbagathi District hospital, Nairobi. Methods This was a cross-sectional study involving 287 pregnant women enrolled for three months (September to December 2014) from Nairobi and neighbouring counties. A structured questionnaire that captured social, demographic and explanatory variables was administered to the study participants. Blood samples were also drawn from the participants and tested for HBV using Enzyme-Linked Immunosorbent Assay (ELISA) system. Results The study established that the prevalence of HBV infections among pregnant women attending antenatal clinic at Mbagathi District Hospital was 3.8% with highest infection rate among the 20-24 years age group. Seventy six (60.8 %) of the participants reported sexual encounters in less than a month before the interview of which 5 (7.6%) reported encounters involving other partners apart from their spouses. HBV awareness among the study participants was 12.2%. Before the interview, those with at least tertiary education (Mean =1.33, SD = 1.131), were more informed about HBV infection as compared to those with primary and secondary education (Mean = 0.63, SD = 0.722; (Mean =0.31, SD= 0.664). In regards to assessment of the risk factors; type of family (χ² =19.753 df2 p<0.01), parity (χ² =7.128 df2 p<0.01), History of abortions (χ²=9.094 df1 p<0.01), early age (11-15 years) at first sexual encounter (χ² =8.185 df1 p<0.01) were significantly associated with HBV positivity. Conclusion The prevalence of HBV infection among pregnant women attending Antenatal clinic (ANC) at Mbagathi District hospital, Nairobi was lower (3.8%) than the prevalence among pregnant women nationally (9.4%). These women also showed a low level of HBV awareness (12.2%.).


Archives of Virology | 2018

Evolutionary analyses of Sindbis virus strains isolated from mosquitoes in Kenya

Faith Sigei; Fredrick Nindo; Silvanos Mukunzi; Zipporah Ng’ang’a; Rosemary Sang

Sindbis virus (SINV) is a mosquito borne virus maintained in nature in a mosquito-bird cycle, with human outbreaks known to occur in Northern Europe and parts of Africa. We analyzed five SINV strains isolated in Kenya from five different mosquito species and geographic locations between 2007 and 2013. Phylogenetic relationships and evolutionary inferences were performed using maximum likelihood and Bayesian phylogenetic inference approaches. Selection analyses were carried out based on the virus envelope glycoproteins (E1, E2) and non-structural protein (nsP4) genes. Phylogenetic analysis revealed that all the Kenyan SINV isolates belonged to genotype 1 with selection analyses suggesting that SINV E1, E2 and nsP4 protein encoding genes were predominantly evolving under negative selection.


The Pan African medical journal | 2016

An in vitro evaluation of drugs used in the Kenyan ART program

Joseph Muriuki; Zipporah Ng’ang’a; Raphael W. Lihana; Raphael Lwembe; Joseph Mwangi; Matilu Mwau

The majority of anti-HIV drug susceptibility tests have been performed on subtype B HIV-1 strains, since these are the most prevalent in countries designing, testing, and manufacturing the current anti-HIV agents. The increasing global spread of HIV subtype highlights the need to determine the activity of anti-HIV drugs against subtypes of HIV other than subtype B. Furthermore an increasing number of individuals infected with many of the non subtype B virus strains now receive antiretroviral therapy because of rollout programs in developing countries as well as increasing migration to the developed world. The phenotypic susceptibility of two laboratory strains HIV-1JFRL and HIV-1IIIB (representing subtype B) and two clinical isolates HIV-104RTA and HIV-1025RTA (representing subtypes A and D respectively) was determined. The in vitro drug susceptibility testing of the isolates was carried out in C8166 cell line and in peripheral blood mononuclear cells (PBMCs). The study revealed that the drugs used in the Kenyan national ART program inhibited HIV-1 replication in-vitro as their inhibitory concentrations (IC50) compared well with the standard Inhibitory concentration values. The results also suggest a biochemical similarity of the reverse transcriptase (RT) and protease enzymes from these subtypes despite the divergence at the genetic level. The findings suggest that similar clinical benefits of antiviral therapy obtain in persons infected with other subtypes of HIV-1other than subtype B and that the generic drugs used in the national ART program in Kenya are as efficacious as branded drugs in inhibiting HIV replication in vitro despite the limited number of the viruses studied.


Infection, Genetics and Evolution | 2013

Genotyping and molecular characterization of hepatitis B virus in liver disease patients in Kenya

Missiani Ochwoto; Ranjit Chauhan; Deepak Gopalakrishnan; Chien-Yu Chen; Zipporah Ng’ang’a; Fredrick A. Okoth; Henry Kioko; James Kimotho; Peter Kaiguri; Anna Kramvis


Parasites & Vectors | 2014

Vector competence of Aedes aegypti populations from Kilifi and Nairobi for dengue 2 virus and the influence of temperature

Edith Chepkorir; Joel Lutomiah; James Mutisya; Francis Mulwa; Konongoi Limbaso; Benedict Orindi; Zipporah Ng’ang’a; Rosemary Sang

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Michael Kiptoo

Kenya Medical Research Institute

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Elizabeth A. Bukusi

Kenya Medical Research Institute

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Fredrick A. Okoth

Kenya Medical Research Institute

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James Kimotho

Kenya Medical Research Institute

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Missiani Ochwoto

Jomo Kenyatta University of Agriculture and Technology

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Raphael Lwembe

Kenya Medical Research Institute

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Raphael W. Lihana

Kenya Medical Research Institute

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Rosemary Sang

Kenya Medical Research Institute

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Edith Chepkorir

International Centre of Insect Physiology and Ecology

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Elijah M. Songok

Kenya Medical Research Institute

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