Raphael W. Lihana
Kenya Medical Research Institute
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Publication
Featured researches published by Raphael W. Lihana.
Journal of Tropical Pediatrics | 2008
Samoel Khamadi; Vincent Okoth; Raphael W. Lihana; Judi Nabwera; Jackson Hungu; Fred Okoth; Kizito Lubano; Matilu Mwau
In Kenya, HIV diagnosis is not routinely carried out in infants, and yet rapid diagnosis could improve access to lifesaving interventions. A cheap and readily accessible service can resolve this problem, if feasible. In this pilot study the feasibility and costs of provision of an infant HIV diagnosis service in Kenya are evaluated. Dried blood spots (DBS) were collected from infants exposed to HIV, sent to a central testing laboratory and tested using the Roche Amplicor v. 1.5 DNA PCR kit. The results were then dispatched to health facilities within a week. A total of 15.4% of the samples tested HIV+ despite the widespread access to prevention of mother to child transmission (PMTCT) programs in Kenya. The cost per test at 21.50 USD is prohibitive and will limit access to diagnosis. It remains to be seen whether the increase in testing will immediately lead to an increase in access to antiretroviral therapy (ART) services for infants.
AIDS Research and Human Retroviruses | 2003
Elijah M. Songok; Raphael W. Lihana; Michael Kiptoo; Isaiah O. Genga; Rukia M. Kibaya; Frida Odhiambo; Kana Kobayashi; Yumi Ago; Nicaise Ndembi; Fredrick A. Okoth; Yoshihide Fujiyama; Jiro Imanishi; Hiroshi Ichimura
As part of a program to determine the genetic diversity of human immunodeficiency virus in rural Kenya, we carried out a molecular analysis of the C2-V3 region of HIV-infected blood samples obtained from 30 antenatal clinic attendees of seven health centers in western Kenya. Direct sequencing was carried out on the envelope C2-V3 region of proviral DNA. On phylogenetic analysis with reference strains, 20 were subtype Al, 2 were subtype D, 1 was subtype C, 1 was subtype G, 1 was CRF-10, 2A/D, 2A/C, and 2 were unclassified. The presence of CRF-10 and the great variety of subtypes and recombinants in such a limited sample size suggest that western Kenya may be a potential hotspot for HIV recombination in the country.
AIDS Research and Human Retroviruses | 2012
Sheila Kageha; Raphael W. Lihana; Vincent Okoth; Matilu Mwau; Fredrick A. Okoth; Elijah M. Songok; Jane Ngaira; Samoel Khamadi
Human immunodeficiency virus 1 (HIV-1) infection is characterized by genetic diversity such that specific viral subtypes are predominant in specific geographic areas. To determine circulating subtypes of HIV-1 in different parts of central Kenya, a cross-sectional study was carried out on HIV-1-positive blood samples collected from consenting individuals in eight hospitals of Kenyas central province. Proviral DNA was extracted from peripheral blood mononuclear cells. Polymerase chain reaction and direct sequencing using primers generated from a highly conserved region of HIV-1 env gp41 were carried out. Ninety-six samples were successfully amplified and sequenced. Analysis of the sequences showed that a majority of them belonged to subtype A1 (67/96, 69.8%), followed by subtypes D (18, 18.7%) and C (11/96, 11.5%). Consistent with findings in other parts of Kenya, HIV-1 subtype A1 was the most dominant virus in circulation. Continued surveillance of circulating subtypes of HIV-1 in Kenya is important in determining the evolution of the HIV/AIDS epidemic in Kenya.
AIDS Research and Human Retroviruses | 2009
Raphael W. Lihana; Samoel Khamadi; Kizito Lubano; Raphael Lwembe; Michael Kiptoo; Nancy Lagat; Joyceline Kinyua; Fredrick A. Okoth; Elijah M. Songok; Ernest P. Makokha; Hiroshi Ichimura
The treatment of HIV-1 infection with antiretroviral drugs has greatly improved the survival of those who are infected. However, HIV-1 diversity and drug resistance are major challenges in patient management, especially in resource-poor countries. To evaluate HIV-1 genetic diversity and drug resistance-associated mutations among drug-naive patients in Kenya prior to antiretroviral therapy (ART), a genetic analysis of HIV-1 pol-RT and env-gp41 was performed on samples collected from 53 (18 males and 35 females) consenting patients between April and June 2005. The average age, baseline CD4(+) T cell counts, and viral loads were 38 (range, 24-62) years, 475 (range, 203-799) cells/mm(3), and 4.7 (range, 3.4-5.9) log(10) copies/ml, respectively. Phylogenetic analysis revealed that 40 samples (75.5%) were concordant subtypes for the two genes and 13 (24.5%) were discordant, suggesting possible recombination and/or dual infections. Prevalent subtypes included A1/A1(pol-RT/env-gp41), 31 (58.5%); D/D, 9 (16.9%); A1/C, 2 (3.8%); A1/D, 4 (7.5%); G/A1, 2 (3.8%); A1/A2, 1 (1.9%); C/A1, 2 (3.8%); D/A1, 1(1.9%); and D/A2, 1 (1.9%). Major reverse transcriptase inhibitor (RTI) resistance-associated mutations were found in four patients (7.5%). Of these patients, three had nucleoside RTI resistance mutations, such as M184V, K65R, D67N, K70R, and K219Q. Nonnucleoside RTI resistance-associated mutations K103N and Y181C were detected in three patients and one patient, respectively. Multiple drug resistance mutations were observed in this drug-naive population. With increasing numbers of patients that require treatment and the rapid upscaling of ART in Kenya, HIV-1 drug resistance testing is recommended before starting treatment in order to achieve better clinical outcomes.
BMC Infectious Diseases | 2009
Raphael W. Lihana; Samoel Khamadi; Raphael Lwembe; Joyceline Kinyua; Joseph Muriuki; Nancy Lagat; Fredrick A. Okoth; Ernest P. Makokha; Elijah M. Songok
BackgroundInfection with HIV-1 is characterized by genetic diversity such that specific viral subtypes are predominant in specific geographical areas. The genetic variation in HIV-1 pol and env genes is responsible for rapid development of resistance to current drugs. This variation has influenced disease progression among the infected and necessitated the search for alternative drugs with novel targets. Though successfully used in developed countries, these novel drugs are still limited in resource-poor countries. The aim of this study was to determine HIV-1 subtypes, recombination, dual infections and viral tropism of HIV-1 among Kenyan patients prior to widespread use of antiretroviral drugs.MethodsRemnant blood samples from consenting sexually transmitted infection (STI) patients in Nairobi were collected between February and May 2001 and stored. Polymerase chain reaction and cloning of portions of HIV-1 gag, pol and env genes was carried out followed by automated DNA sequencing.ResultsTwenty HIV-1 positive samples (from 11 females and 9 males) were analyzed. The average age of males (32.5 years) and females (26.5 years) was significantly different (p value < 0.0001). Phylogenetic analysis revealed that 90% (18/20) were concordant HIV-1 subtypes: 12 were subtype A1; 2, A2; 3, D and 1, C. Two samples (10%) were discordant showing different subtypes in the three regions. Of 19 samples checked for co-receptor usage, 14 (73.7%) were chemokine co-receptor 5 (CCR5) variants while three (15.8%) were CXCR4 variants. Two had dual/mixed co-receptor use with X4 variants being minor population.ConclusionHIV-1 subtype A accounted for majority of the infections. Though perceived to be a high risk population, the prevalence of recombination in this sample was low with no dual infections detected. Genotypic co-receptor analysis showed that most patients harbored viruses that are predicted to use CCR5.
AIDS Research and Human Retroviruses | 2009
Samoel Khamadi; Raphael W. Lihana; Saida Osman; Joseph Mwangi; Joseph Muriuki; Nancy Lagat; Joyceline Kinyua; Matilu Mwau; Sheila Kageha; Vincent Okoth; Washington Ochieng; Fredrick A. Okoth
A study on the genetic diversity of HIV-1 subtypes present along the coastal strip of Kenya, i.e., Kilifi, Mombasa, Msambweni, and Malindi districts, was carried out. DNA sequences for regions encoding a portion of the env-gp41 region of the virus were generated by PCR and sequenced directly. Eighty six samples that were successfully sequenced were analyzed. From the analysis, 86% (74) were subtype A1, 5% (4) were subtype C, 8% (7) were subtype D, and 1% (1) was subtype G. This study shows that HIV-1 subtype A1 is the most dominant subtype in circulation in this region.
Intervirology | 2008
Joseph Mwangi; Zipporah Ng'ang'a; Elijah M. Songok; Joyceline Kinyua; Nancy Lagat; Joseph Muriuki; Raphael W. Lihana; Samoel Khamadi; Saida Osman; Raphael Lwembe; Michael Kiptoo; Matilu Mwau; Ruth Chirchir; Solomon Mpoke; Jack Nyamongo; Fred Okoth; Rika Yamada; Seiji Kageyama; Hiroshi Ichimura
Eight genotypes of hepatitis B virus (A-H) and subgenotypes have been recognized worldwide. However, there is limited information on prevalent genotypes in many countries in Africa. This study was undertaken to determine the hepatitis B virus (HBV) genotypes in Kenya. Seropositive HBV blood samples from a blood donor setting were used in the study. HBV genotypes were determined in 52 nucleic acid-positive samples using specific primer in a nested PCR and sequencing employed in the HBV genotyping. This study shows presence of HBV variants with genotypes A (88%), E (8%) and D (4%). In conclusion, we found that HBV genotype A is the most predominant genotype in Kenya with both subgenotype A1 and A2 present. Genotype D and E are also present in our population. This demonstrates that there could be a high genetic diversity of HBV in Kenya.
AIDS Research and Human Retroviruses | 2009
Raphael W. Lihana; Samoel Khamadi; Raphael Lwembe; Washingtone Ochieng; Joyceline Kinyua; Michael Kiptoo; Joseph Muriuki; Nancy Lagat; Saida Osman; Joseph Mwangi; Fredrick A. Okoth; Elijah M. Songok
Monitoring the distribution of HIV-1 subtypes and recombinants among infected individuals has become a priority in HIV therapy. A laboratory analysis of samples collected from HIV-positive patients attending an STI clinic in Nairobi was done between March and May 2004. PCR was carried out on pol (intergrase) and env (C2V3) regions and resulting data on the 54 samples successfully analyzed revealed the following as circulating subtypes: 35/54(65%) were A1/A1, 5/54(9%) were A/C, 4/54 (7%) were A1/D, 1/54 (2%) was C/D, 1/54 (2%) was D/D, 1/54 (2%) was A1/A2, 1/54 (2%)was G/G, 1/54 (2%) was A2/D, 1/54 (2%) was C/C, and 4/54 (7%) were CRF02_ AG. The results show an increase in HIV-1 recombinants with the emergence of A1/A2 and an increase in CRF02_AG recombinants. Subtype diversity in the advent of ARV use will impact negatively on treatment outcomes. As such, increased viral evolution and recombination will call for continuous evaluation of available anti-HIV regimens for better management of those infected with HIV-1.
Aids Research and Therapy | 2012
Veronica Wambui; Michael Kiptoo; Joyceline Kinyua; Irene Odera; Edward Muge; Peter Muiruri; Raphael W. Lihana; Peter Kinyanjui; Elijah Songok
BackgroundCCR5 antagonists have clinically been approved for prevention or treatment of HIV/AIDS. Countries in Sub-Saharan Africa with the highest burden of HIV/AIDS are due to adopt these regimens. However, HIV-1 can also use CXCR4 as a co-receptor. There is hence an urgent need to map out cellular tropism of a country’s circulating HIV strains to guide the impending use of CCR5 antagonists.ObjectivesTo determine HIV-1 coreceptor usage among patients attending a comprehensive care centre in Nairobi, Kenya.MethodsBlood samples were obtained from HIV infected patients attending the comprehensive care centre, Kenyatta National Hospital in years 2008 and 2009. The samples were separated into plasma and peripheral blood mononuclear cells (PBMCs). Proviral DNA was extracted from PBMCs and Polymerase Chain reaction (PCR) done to amplify the HIV env fragment spanning the C2-V3 region. The resultant fragment was directly sequenced on an automated sequencer (ABI, 3100). Co-receptor prediction of the env sequences was done using Geno2pheno[co-receptor], and phylogenetic relationships determined using CLUSTALW and Neighbor Joining method.ResultsA total of 67 samples (46 treatment experienced and 21 treatment naive) were successfully amplified and sequenced. Forty nine (73%) sequences showed a prediction for R5 tropism while 18(27%) were X4 tropic. Phylogenetic analysis showed that 46(69%) were subtype A, 11(16%) subtype C, and 10(15%) subtype D. No statistical significant associations were observed between cell tropism and CD4+ status, patient gender, age, or treatment option. There was a tendency for more X4 tropic strains being in the treatment experienced group than the naive group: Of 46 treatment experiencing participants, 14(30%) harboured X4, compared with 4(19%) of 21 of the treatment-naïve participants, the association is however not statistically significant (p = 0.31). However, a strong association was observed between subtype D and CXCR4 co- receptor usage (p = 0.015) with 6(60%) of the 10 subtype D being X4 tropic and 4(40%) R5 tropic.ConclusionHIV-1 R5 tropic strains were the most prevalent in the study population and HIV infected patients in Kenya may benefit from CCR5 antagonists. However, there is need for caution where subtype D infection is suspected or where antiretroviral salvage therapy is indicated.
Journal of Medical Virology | 2011
Cuong Hung Nguyen; Azumi Ishizaki; Phan Thi Thu Chung; Huyen Thi Thanh Hoang; Trung Vu Nguyen; Tomoaki Tanimoto; Raphael W. Lihana; Kaori Matsushita; Xiuqiong Bi; Thuc Van Pham; Hiroshi Ichimura
Hepatitis B virus (HBV) infection in Hai Phong, northern Vietnam, was characterized by analyzing the prevalence and genotype distribution of HBV as well as co‐infection with human immunodeficiency virus type 1 (HIV‐1) among five different risk groups for HIV infection. Plasma samples were collected from intravenous drug users (n = 760, anti‐HIV‐1 antibody positive rate: 35.9%), female sex workers (FSWs; n = 91, 23.1%), seafarers (n = 94, 0%), pregnant women (n = 200, 0.5%), and blood donors (n = 210, 2.9%) in 2007 [Ishizaki et al. (2009): AIDS Res Hum Retroviruses 25:175–182]. Samples were screened for the hepatitis B surface antigen (HBsAg) and anti‐HBs antibody and analyzed genetically. The cumulative HBV incidence rate (HBsAg + anti‐HBs) was 53.2% (10.7 + 42.5%) in intravenous drug users, 51.6% (11.0 + 40.6%) in FSWs, 54.3% (9.6 + 44.7%) in seafarers, 50.5% (12.5 + 38.0%) in pregnant women, and 51.0% (18.1 + 32.9%) in blood donors; there was no significant difference among these groups. Of 163 HBsAg‐positive samples, 113 could be analyzed genetically. Phylogenetic analysis, based on the preS1 region, revealed genotype B4 was most prevalent (90/113; 79.6%), followed by C1 (17.7%), I1 (1.8%), and B2 (0.9%). There was no significant difference in HBV genotype distribution among different HIV infection‐risk groups. The prevalence of HBsAg was 10.3% (31/301) in HIV‐1‐infected individuals and 12.5% (132/1,054) in non‐HIV‐1‐infected individuals, which was not significant. In addition, no significant difference in HBV genotype distribution was observed between HBV/HIV‐1 co‐infected and HBV mono‐infected groups. These results suggest that, although HBV and HIV‐1 share modes of transmission, major transmission routes of HBV have been different from those of HIV‐1 in Hai Phong, Vietnam. J. Med. Virol. 83:399–404, 2011.