HIV-1 subtype and viral tropism determination for evaluating antiretroviral therapy options: an analysis of archived Kenyan blood samples.

BACKGROUND: Infection 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. METHODS: Remnant 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. RESULTS: Twenty 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. CONCLUSION: HIV-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.

HIV type 1 subtypes among STI patients in Nairobi: a genotypic study based on partial pol gene sequencing.

Circulating strains of human immunodeficiency virus (HIV) exhibit an extraordinary degree of genetic diversity and have been classified on the basis of relationships into distinct lineages called groups, types, subtypes, and subsubtypes. Sexually transmitted infections (STIs) are known to be a risk factor for HIV infection. To establish HIV-1 subtype diversity among STI patients in Nairobi, 140 samples were collected and partial pol gene sequencing done. From the analysis it was established that subtype A1 was the major subtype (64%) followed by D (17%), C (9%), G (1%), and recombinants AD (4%), AC (3%), CRF02()AG (1%), and CRF16()A2D (1%). These results suggest that the HIV-1 epidemic may be evolving toward more virulent and complex subtypes through transmission of complex recombinants due to viral mixing. Any use of ARVs may therefore require initial testing for de novo resistance before commencement of treatment and/or management.

HIV type 1 subtypes in circulation in northern Kenya.

The genetic subtypes of HIV-1 circulating in northern Kenya have not been characterized. Here we report the partial sequencing and analysis of samples collected in the years 2003 and 2004 from 72 HIV-1-positive patients in northern Kenya, which borders Ethiopia, Somalia, and Sudan. From the analysis of partial env sequences, it was determined that 50% were subtype A, 39% subtype C, and 11% subtype D. This shows that in the northern border region of Kenya subtypes A and C are the dominant HIV-1 subtypes in circulation. Ethiopia is dominated mainly by HIV-1 subtype C, which incidentally is the dominant subtype in the town of Moyale, which borders Ethiopia. These results show that cross-border movements play an important role in the circulation of subtypes in Northern Kenya.

Characterization of HBV Among HBV/HIV-1 Co-Infected Injecting Drug Users from Mombasa, Kenya.

BACKGROUND: Hepatitis B (HBV) and Human Immunodeficiency virus (HIV) are both bloodborne viruses. Markers of either active or past HBV infection are present in many HIV infected patients. Worldwide, HBV prevalence varies geographically and endemicity is classified as low (<2%) or high (>8%). Genotypically, prevalence varies among different populations, with genotype A having a wide distribution. In Kenya, the prevalence of HIV-1/HBV co-infection ranges from 6-53% depending on the sub-population, with genotype A as the most common. OBJECTIVE: To determine the prevalence and characterize HBV in HBV/HIV co-infected injecting drug users (IDUs) from Mombasa, Kenya. METHODS: Blood samples were collected from HIV-infected IDUs in Mombasa, Kenya. Hepatitis B surface antigen (HBsAg) was tested by enzyme immunoassay (EIA). HBV DNA was extracted by SMITEST R&D kit. Polymerase chain reaction (PCR) was done; followed by population sequencing of HBV preS, core and full genome using specific primers. Analysis was done phylogenetically with reference sequences from the Genbank. RESULTS: Seventy two HIV-positive samples were collected from IDUs in Mombasa in February and March 2010. Of these, 10 (13.89%) were HBsAg-positive by EIA. Nine of the 10 samples (12.5%) were PCR positive for HBV in the preS region; from these, four HBV full length sequences were obtained. Phylogenetic analysis showed that all belonged to genotype A1. CONCLUSION: The prevalence of HBV co-infection among HIV-infected IDUs in Mombasa, Kenya was 12.5%. Phylogenetically, sequences obtained from this study showed clusters that were distinct from reported Kenyan reference sequences from the Genbank. The findings point to an existence of a transmission network among IDUs in Mombasa. This further suggests that HBV genotypes in Kenya may be regionally diverse.

Diversity of HIV type 1 and drug resistance mutations among injecting drug users in Kenya.

Drug use in Kenya dates back to the precolonial period but research among drug users in relation to human immunodeficiency virus (HIV)-associated risk and intervention strategies has been low. To evaluate HIV-1 diversity and drug resistance among injecting drug users (IDUs), a cross-sectional study involving 58 patients was carried out in Mombasa between February and March 2010. HIV-1 RNA was extracted from plasma and polymerase chain reaction using specific primers for HIV-1 reverse transcriptase was done. Population sequencing was done and subtypes were determined phylogenetically. The prevalent HIV-1 subtypes were A1 (52/58), D (5/58), and C (2/58). The prevalence of drug resistance was 13.8% (8/58) with detection of nucleoside reverse transcriptase inhibitor (NRTI) mutations, T215F (n=5), K219Q (n=3), M184V (n=1), and nonnucleoside RTI mutation, K103N (n=1). Antiretroviral therapy (ART) and its monitoring among infected Kenyan IDUs is feasible. Policymakers and service providers in HIV prevention initiatives should improve service delivery so as to measure ART coverage among IDUs to prevent further transmission of drug-resistant variants.

HIV type 1 subtype surveillance in central Kenya.

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 Kenya's 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.

Genetic characterization of HIV type 1 among patients with suspected immune reconstitution inflammatory syndrome after initiation of antiretroviral therapy in Kenya.

Antiretroviral therapy (ART) has improved the survival of HIV patients but is also associated with unique manifestations of disease in some subjects during the initial months of therapy. Immune reconstitution inflammatory syndrome (IRIS) is a disorder among individuals starting ART, with no evidence-based treatment and management guidelines. We characterized HIV-1 and determined drug resistance among 14 Kenyan patients with suspected IRIS after ART initiation in 2005. Polymerase chain reaction, sequencing, and phylogenetic analysis of viral pol and env showed the following HIV-1 subtypes: A1/A1/A1 (pol-RT/gp41/C2V3), 5; A1/C/A1, 1; A1/D/A1, 2; D/A1/A1, 1; D/C/A1, 1; D/D/A1, 2; D/D/D, 1; and D/A1/A2, 1. Three patients had viruses with major drug resistance-associated mutations. These included nucleoside reverse transcriptase inhibitor (RTI) mutations: M41L, K65R, D67N, K70R, M184V, and K219Q, and nonnucleoside RTI mutations: K101P, L100I, K103N, and Y181C. Twelve patients harbored viruses that are predicted to use chemokine coreceptor 5 (CCR5) whereas two had variant viruses predicted to use the CXCR4 coreceptor. Drug resistance may not be the only cause of ART adverse events. HIV-1 characterization would be important before and during HIV therapy to avoid treatment failure.

HIV type 1 subtype diversity and drug resistance among HIV type 1-infected Kenyan patients initiating antiretroviral therapy.

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.

The changing trend of HIV type 1 subtypes in Nairobi.

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.

Genetic diversity of HIV type 1 along the coastal strip of Kenya.

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.

HIV type 1 genetic diversity in Moyale, Mandera, and Turkana based on env-C2-V3 sequences.

The genetic diversity of HIV-1 subtypes circulating in three districts of northern Kenya, i.e., Turkana, Mandera, and Moyale, was studied. DNA sequences encoding a portion of the env-C2-V3 region of the virus were amplified by PCR and sequenced directly. One hundred and fifty-nine samples were successfully sequenced in the env-C2-V3 region and analyzed. From the analysis, 57% were subtype A1, 27% were subtype C, 9% were subtype D, and the remaining 7% were unclassified. This study showed that HIV-1 subtype A1 was the dominant subtype in circulation in this region, though there was a significant percentage of HIV-1 subtype C in circulation there.

Patterns of upper gastrointestinal diseases based on endoscopy in the period 1998-2001.

Upper gastrointestinal complaints are common in Kenya. Though these have remained unchanged over the last 20 years, the pattern of upper gastrointestinal disease on endoscopic examination seems to be changing. There appears to be progressive increase in oesophagitis and cancer of the stomach. Peptic ulcer disease has remained stable while Cancer of the oesophagus is still common. The paper intends to report on endoscopic findings at the Centre for Clinical Research, Kenya Medical Research Institute (KEMRI) over the period October 1998 and May 2001. The sources of information are records made at the time of endoscopy and histology reports on biopsies taken. Seven hundred and sixty eight patients were endoscoped. The male to female ratio was 1.7:1 with mean age +/-SD of 40.8 +/-20.1 years and age range was 3 to 96 years. Majority of the patients had abnormal findings with gastritis being the most common ( 25.8%). It is concluded that gastritis is an important cause of morbidity in Kenya. Oesophagitis, mainly due to gastroesophageal reflux disease, seems to be on the increase. Gastric cancer is not as rare as previously thought and peptic ulcer disease is still common.

Yellow fever outbreak, Imatong, southern Sudan.

In May 2003, the World Health Organization received reports about a possible outbreak of a hemorrhagic disease of unknown cause in the Imatong Mountains of southern Sudan. Laboratory investigations were conducted on 28 serum samples collected from patients in the Imatong region. Serum samples from 13 patients were positive for immunoglobulin M antibody to flavivirus, and serum samples from 5 patients were positive by reverse transcription-polymerase chain reaction with both the genus Flavivirus-reactive primers and yellow fever virus-specific primers. Nucleotide sequencing of the amplicons obtained with the genus Flavivirus oligonucleotide primers confirmed yellow fever virus as the etiologic agent. Isolation attempts in newborn mice and Vero cells from the samples yielded virus isolates from five patients. Rapid and accurate laboratory diagnosis enabled an interagency emergency task force to initiate a targeted vaccination campaign to control the outbreak.