Detection of Transversions and Transitions in HBG2 Cis-Elements Associated with Sickle Cell Allele in Ghanaians.

Short tandem repeats located 5' prime to the ß-globin gene, have been observed to be in linkage disequilibrium with the HbS allele, and thought to affect the severity of sickle cell disease. Here, we report on new mutants within the HBG2 region that may impact sickle cell disease. To determine the cis-acting elements microsatellites, indels and single nucleotide polymorphisms (SNPs), within the HBG2 region by sequencing, in subjects with sickle cell disease. The case-control study was located at the Center for Clinical Genetics, Sickle cell unit, Korle-Bu Teaching Hospital. A questionnaire was used for demographic data and clinical information. Hematological profile (red blood cell, white blood cell, platelet, hemoglobin and mean corpuscular volume) were assessed in 83 subjects. A set of 45 samples comprising amplified DNA on the HBG2 gene from HbSS (22), HbSC (17) and 6 controls (HbAA) were sequenced. Differences in the microsatellite region between sickle cell disease (SCD) (HbSS and HbSC) genotypes and control subjects were identified by counting and assessed by Chi-square analysis. Red blood cells, hematocrit, platelets, white blood cells and hemoglobin indices differed in genotypic groups. HbSS subjects were affirmed to have severer hemolytic anemia than HbSC subjects. Two indels (T1824 and C905) were seen in both SS and SC genotypes. Two peculiar SNPs: G:T1860 (transition) and A:G1872 transversions were found within the HBG2 gene that were significantly associated with the HbSS genotype (Fisher's exact test, p = 0.006) and HbS allele respectively (Fisher's exact test, p = 0.006). Cis-acting elements in HbSS and HbSC were different and may contribute to the phenotype seen in the disease state.

Crimean-Congo hemorrhagic fever virus in livestock ticks and animal handler seroprevalence at an abattoir in Ghana.

BACKGROUND: Crimean-Congo Haemorrhagic Fever Virus (CCHFV) is a zoonotic virus transmitted by Ixodid ticks and causes Crimean-Congo hemorrhagic fever (CCHF) disease in humans with up to 50 % mortality rate. METHODS: Freshly slaughtered livestock at the Kumasi abattoir in the Ashanti Region of Ghana were examined for the presence of ticks once a month over a 6-month period from May to November 2011. The ticks were grouped into pools by species, sex, and animal source. CCHFV was detected in the ticks using reverse transcription PCR. Blood samples were collected from enrolled abattoir workers at initiation, and from those who reported fever in a preceding 30-day period during monthly visits 2-5 months after initiation. Six months after initiation, all participants who provided baseline samples were invited to provide blood samples. Serology was performed using enzyme linked immunosorbent assay (ELISA). Demographic and epidemiological data was also obtained from enrolled participants using a structured questionnaire. RESULTS: Of 428 freshly slaughtered animals comprising 130 sheep, 149 cattle, and 149 goats examined, 144 ticks belonging to the genera Ambylomma, Hyalomma and Boophilus were identified from 57 (13.3 %): 52 (34.9 %), 4 (3.1 %) and 1 (0.7 %) cattle, sheep and goat respectively. Of 97 tick pools tested, 5 pools comprising 1 pool of Hyalomma excavatum and 4 pools of Ambylomma variegatum, collected from cattle, were positive for CCHFV. Of 188 human serum samples collected from 108 abattoir workers, 7 (3.7 %) samples from 6 persons were anti-CCHF IgG positive with one of them also being CCHF IgM positive. The seroprevalence of CCHFV identified in this study was 5.7 %. CONCLUSIONS: This study detected human exposure to CCHF virus in slaughterhouse workers and also identified the CCHF virus in proven vectors (ticks) of Crimean Congo hemorrhagic fever in Ghana. The CCHFV was detected only in ticks collected from cattle, one of the livestock known to play a role in the amplification of the CCHF virus.

Prevalence of hepatitis d infection in patients with hepatitis B virus-related liver diseases in Accra, Ghana.

BACKGROUND: Hepatitis D virus (HDV), a defective RNA virus which depends on hepatitis B virus (HBV) for its replication and expression, appears to be highly pathogenic and modifies the natural history of HBV infection. Two types of infection, co-infection and super-infection are recognised. During infection, anti-delta antibodies appear in serum and can be detected by Enzyme linked Immunosorbent Assay (ELISA). OBJECTIVE: We determined the prevalence of hepatitis D infection amongst HBsAg-positive patients with HBV-related liver diseases in Accra, Ghana using an Enzyme linked Immunosorbent assay (ELISA) method. METHODS: We collected blood samples from 53 patients with hepatitis B-related liver diseases. The sera were analysed using a commercially available kit, the EIA-ANTI-HDV, a third generation ELISA kit (Globe Diagnostics, Italy). RESULTS: There were 39 males (73.6%) and 14 females (26.4%) giving a male:female ratio of about 3:1.The mean age of patients was 38.6 years (range, 15-75). Six patients were reactive for anti-delta antibodies, yielding a HDV sero-prevalence of 11.3%. A higher proportion of males were anti-HDV positive (9.4%) compared to females (1.9%) but the difference was not statistically significant (p=0.350). Anti-HDV was detected in 4(22.2%) patients with chronic hepatitis B, 1(7.6%) with cirrhosis of the liver and 1(5.3%) with hepatocellular carcinoma. CONCLUSION: The prevalence of HDV infection amongst patients with liver disease in Accra with HBV-related liver diseases appears to be high compared to developed countries but similar to several developing countries. No significant difference exists in gender prevalences. A concerted public health effort is required to reduce this high prevalence rate.

Low level of transmitted HIV Drug resistance at two HIV care centres in Ghana: a threshold survey.

BACKGROUND: As access to antiretroviral therapy (ART) increases, the emergence and transmission of HIV drug resistant strains becomes a major problem. The World Health Organization (WHO) therefore recommends an initial minimum-resource method to signal when transmitted HIV drug resistance (HIVDR) requires action. OBJECTIVE: This survey sought to generate information on the presence of HIV drug-resistant strains in the locality where Ghana's ART for HIV was first introduced. METHODS: The Ghana HIVDR threshold survey (TS) was conducted and analyzed according to WHO strategy for surveillance of HIVDR in the Eastern Region of Ghana. Sixty (60) plasma specimens were collected from 2007 to 2009 by an unlinked anonymous method from HIV seropositive pregnant women, aged between 15 to24 years, who were with their first pregnancy and ART naive. Genotyping was done as follows; Ribonucleic acid (RNA) was extracted from the samples and the protease (PR) and reverse transcriptase (RT) genes amplified and sequenced. The sequences were then analyzed for HIV drug resistance mutations using Stanford University HIV Drug Resistance Database. RESULTS: Only two individuals were found with major HIVDR mutations: one each in the PR and RT genes. Thus the level of HIVDR in the study population in 2009 was classified as low (< 5%). CONCLUSION: As at February 2009, transmitted drug resistance was not a serious problem in the Eastern Region of Ghana. However, it is important to continue monitoring tHIVDR in order to understand the dynamics of the evolution of HIV drug resistance in the country.

Laboratory diagnosis of dual HIV-1/HIV-2 infection in Ghanaian patients.

OBJECTIVE: To determine the true prevalence of HIV dual infections in a previously characterised HIV seropositive patient group due to inconsistencies between different diagnostic methods. DESIGN: A cross-sectional study of an HIV seropositive group with different diagnostic methods. SETTING: Three hospitals in the Northern, Ashanti and Greater Accra Regions of Ghana. SUBJECTS: One hundred and forty five HIV infected patients/individuals sampled from June to September 2002. MAIN OUTCOME MEASURES: Using serological and molecular methods, the seropositive status of HIV-infected patients, previously determined by a preliminary screening process, was confirmed and discrepancies noted. The data was used to propose a more accurate laboratory diagnosis of HIV dual infections involving HIV-1 and HIV-2. RESULTA: HIV-1 infections were mostly accurately detected, but difficulties were encountered in diagnosing HIV-2 infections. To achieve a positive detection on confirmatory immunoblots, antibody concentration in some samples tested was enhanced by using larger volumes. In other cases, diagnosis of HIV infections by PCR, especially HIV-2, was possible only after increasing the DNA template or MgCl2 concentrations. Such samples would otherwise have been inaccurately scored for HIV infections. CONCLUSION: Based on the results of this study, we propose that the accurate diagnosis of HIV dual infections, especially HIV-2 component, must use an algorithm that involves PCR. Our results however underscore conclusions of a previous study that most dually seroreactive samples are predominantly HIV-1 infections with crossreactivity to HIV-2 antigens.

Phenotypic characterization of HIV type 1 isolates from Ghana.

Viral isolates from 27 HIV-1-infected patients in Ghana, most of whom were symptomatic, were characterized for coreceptor usage using MT-2 and U87.CD4 cells. Irrespective of clinical status, most infections were caused by CCR5-tropic viruses although three CXCR4-tropic viruses were also found. Genotyping was performed by sequencing the gp41 region. Seven viruses clustered with subtype G reference strains, while the remaining 20 viruses clustered within the subtype A reference viruses. Most subtype A isolates clustered loosely with the CRF02_AG viruses and are described as CRF02_AG-like. The V3 loop was sequenced in selected isolates including all isolates capable of using CXCR4. The V3 region of CXCR4-using viruses contained genetic traits characteristic of CXCR4-using subtype B and C viruses, such as increased charge, the presence of positively charged residues at positions 11 and 25, and loss of a predicted glycosylation site. This study supports previous work showing that CRF02_AG is responsible for most HIV-1 infections in Ghana at this time. The predominance of CCR5-using viruses, even in symptomatic patients, suggests that CCR5-blocking strategies may be useful for prevention and treatment of HIV-1 infections in Ghana.

HIV-1 proteases from drug-naive West African patients are differentially less susceptible to protease inhibitors.

BACKGROUND: Now that highly active antiretroviral therapy (HAART) is being initiated on a large scale in West Africa, it remains controversial whether protease inhibitors (PIs), originally designed and tested against human immunodeficiency virus type 1 (HIV-1) subtype B, are equally effective against the non-B subtypes that are prevalent in West African countries. In this study, we investigated whether Ghanaian HIV-1 isolates, as representatives of West African isolates, are susceptible to PIs. METHODS: We first generated an HIV-1 protease cassette vector proviral DNA carrying a luciferase gene, which allows patient-derived HIV-1 proteases to be inserted and to be subjected to both genotypic and phenotypic assays. HIV-1 protease genes derived from 39 treatment-naive Ghanaian patients were used in this experiment as representatives of West African strains. The cloned patient-derived HIV-1 protease genes were first sequenced and then genetically compared. Phenotypic analysis was performed with Ghanaian HIV-1 protease-chimeric viruses in the presence of 6 different PIs. Structural models of HIV-1 protease homodimers were constructed by the molecular modeling software. RESULTS: Genetic analysis of cloned patient-derived HIV-1 protease genes indicated that most of the Ghanaian HIV-1 proteases are placed as subtype CRF02_AG strains, which are phylogenetically distant from subtype B strains, and that Ghanaian HIV-1 proteases do not harbor known major mutations influencing drug resistance but commonly carry 2-3 minor mutations. Phenotypic analysis performed with HIV-1 protease-recombinant viruses in the presence of 6 different PIs revealed that Ghanaian HIV-1 proteases are differentially less susceptible to the PIs. In support of this finding of differential susceptibility, structural analysis showed a significant distortion of nelfinavir, but not of amprenavir, in the Ghanaian protease pocket, suggesting nelfinavir might be less insertable into the Ghanaian protease than into the protease of subtype B. CONCLUSIONS: These findings provide implications for the combination of PIs during the introduction of HAART into West Africa.

Suitability of a rapid immunochromatographic test for detection of antibodies to human immunodeficiency virus in Ghana, West Africa.

In West African countries such as Ghana, efficient human immunodeficiency virus (HIV) testing is a priority in the fight against AIDS. A new immunochromatographic rapid test, Determine HIV-1/2 (Abbott Diagnostics, North Chicago, Ill.), that detects antibodies against HIV type 1 (HIV-1) and/or HIV-2 was evaluated using Ghanaian blood samples. Two hundred four serum and/or plasma specimens were tested. HIV screening was done by a particle agglutination test and confirmed by a Western blot (WB) test as the "gold standard." The results revealed 125 HIV-seropositive AIDS patients, 75 HIV-seronegative healthy individuals, and 4 individuals for whom the HIV-1 result was indeterminate. The results obtained by the Determine HIV-1/2 assay and Diagnostic HIV SPOT (Genelabs), which is currently widely used in many districts in Ghana, were compared with those of the WB test, excluding the four HIV-1-indeterminate samples. The sensitivity of the Determine HIV-1/2 assay was 100%, compared with 98.0% for the HIV SPOT assay. The specificity was 100% for both tests. Determine HIV-1/2 is a single-step assay and was found to be rapid and easy to perform without any special equipment. It was highly sensitive and specific. The kit can be applied without electricity and water supplies, making it suitable for the detection of HIV antibodies especially in the rural areas of Ghana, West Africa.

Isolation and characterization of a full-length molecular DNA clone of Ghanaian HIV type 1 intersubtype A/G recombinant CRF02_AG, which is replication competent in a restricted host range.

We have isolated a replication-competent, full-length molecular clone of HIV-1 CRF02_AG, designated p97GH-AG1, by reconstituting two separately amplified genomic regions of an HIV-1 provirus of a 1997 Ghanaian isolate. The phylogenetic and recombination breakpoint analyses revealed that 97GH-AG1 had an A/G recombinant structure similar to that of prototype Nigerian isolate IbNG. The 17-nucleotide insertion downstream of the primer-binding site appeared to be a common sequence signature specific to most CRF02_AG strains, including 97GH-AG1. 97GH-AG1 showed an R5 phenotype and exerted productive infection in both HOS and NP2 cell infectivity assays, whereas it failed to show a detectable level of progeny production in peripheral blood mononuclear cells (PBMCs). The data may suggest the presence of unknown determinant(s) that dictate efficient replication in PBMCs, but that are not required for replication in immortalized cell lines.

Genetic analysis of HIV type 2 from Ghana and Guinea-Bissau, West Africa.

The phylogenetic variability of part of the long terminal repeat (LTR) region of HIV-2 strains isolated in 1995 from five individuals residing in Bissau, the capital city of Guinea-Bissau, and collected from seven persons from Kumasi, Ghana in 1996-1997, was analyzed. All Guinean samples and all but one Ghanaian sample clustered with HIV-2 subtype A. One Ghanaian sample (14%) was classified as HIV-2 subtype B. This study adds to previous reports on HIV-2 subtype distribution in West Africa indicating local prevalence of HIV-2 subtype B in Ivory Coast and neighboring Ghana.

Haptoglobin phenotypes in HIV-1-seropositive patients in Ghana: decreased risk for Hp0 individuals.

Plasma haptoglobin phenotypes were determined by polyacrylamide gel electrophoresis, followed by benzidine staining for 58 HIV-1 seropositive Ghanaians and 79 randomly selected age-matched controls. Hp0 was present in only 14% of HIV-1 seropositive individuals compared with more than 40% of the controls. The Hp0 individuals showed a highly significant reduced risk for HIV-1 infection (OR = 0. 21, 95% CI = 0.09-0.51, p = 0.0002). Hp0 may have a protective effect in HIV-1 infection.

Haptoglobin polymorphism in human immunodeficiency virus infection: Hp0 phenotype limits depletion of CD4 cell counts in HIV-1-seropositive individuals.

Patients seropositive for human immunodeficiency virus (HIV) type 1 and seronegative control subjects were categorized by their haptoglobin phenotypes, which were determined by electrophoresis of hemoglobin-supplemented plasma samples followed by benzidine staining. The CD4 cell counts, determined by flow cytometry from peripheral blood mononuclear cells according to subject categories, were severely diminished in seropositive patients with the Hp2-2 phenotype (P<.025). In contrast, the CD4 cell counts for patients with the Hp0 phenotype remained relatively high (P<.025), compared with those of the controls. In seronegative patients, CD4 cell counts were generally high (P<.005), but they were more elevated in subjects with Hp2-2 and Hp1-1, although the differences were not significant. Thus, the Hp2-2 phenotype is associated with poor outcome in HIV-1 infection, whereas the Hp0 phenotype is associated with a better prognosis once the patient is infected with HIV-1. Haptoglobin polymorphism plays a significant role in HIV-1 infection and transmission.

Relationship between immunoclinical status and prevalence of viral sexually transmitted diseases among human immunodeficiency virus-1 seropositive patients in Ghana.

In view of the strong association between the acquired immunodeficiency syndrome (AIDS) and sexually transmitted diseases (STDs), we screened 182 human immunodeficiency virus (HIV)-1 infected patients over a 15-month period for serological markers to previously encountered or current STDs, most of viral etiology. The relationship between their immunological and clinical status and the prevalence of STDs was assessed and compared with that of 88 HIV-seronegative patients. Hepatitis B virus and Treponema pallidum were the most frequently occurring pathogens in both HIV-1-infected and HIV-seronegative patients. Hepatitis C virus (HCV) infection was also observed in both groups, but no HIV-seronegative patient was infected with human T-lymphotropic virus type 1 (HTLV-1). The Centers for Disease Control clinical staging of A1 through C3, representing asymptomatic to severe AIDS conditions, was observed in HIV-1 patients with or without STDs. A mean CD4 count of 288 cells per microliter (95% CI of 237-340 cells per microliter) in HIV-1 patients was significantly lower (P < 0.05) than that in HIV-seronegative individuals with 1019 cells per microliter (95% CI of 924-1115 cells per microliter), irrespective of whether subjects in either group had previous or current STDs. The mean CD4 count of patients with a single infection from HIV-1 was not significantly different (P = 0.36) from that of HIV-1 patients with multiple infections. HIV-1 infection alone appears to be responsible for the marked immunodeficiency status of seropositive patients observed in this study.

Seroreactivity clarification and viral load quantitation in HIV-1 and HIV-2 infections in Ghana.

In Ghana, West Africa, the prevalence of dual HIV-1 and HIV-2 infections remains to be clarified, and HIV viral load measurement is yet to be established. Conventional assays for HIV-1 RNA measurements have been limited specifically to HIV-1 subtype B, preventing their utilization for Ghana where HIV-1 subtypes A, D and G are prevalent. Therefore, we set out to distinguish the types of HIV infection existing in Ghana so as to determine the extent of actual dual infections, and to measure plasma HIV-1 RNA. Blood samples were collected from 563 sick and healthy Ghanaians who visited hospitals in 1996 and 1997. After T cells were counted, HIV antibody was screened and confirmed by six different commercial assays and one in-house test. Nested PCR was then used to verify HIV-1 and HIV-2 presence by type-specific primers. Plasma HIV-1 RNA was measured by an improved commercial RT-PCR assay, sensitive to all HIV-1 group M subtypes. HIV-1 alone (89%) clearly dominated over HIV-2 alone (2%), and HIV-1 and HIV-2 dual infections were found in 9%. Valid viral load measurements were obtained on test plasma representing the main HIV-1 subtype (A) prevailing in Ghana. A high amount of HIV-1 RNA (5.9 mean log10 RNA copies/ml) was observed in the typical stages of HIV infection represented by groups of CD44 cell counts. We have clarified the seroprevalence of HIV-1 and HIV-2 amongst HIV seropositives, and the high viral load of HIV-1 reflects its influence on AIDS in Ghana.

Phylogenetic analysis of human immunodeficiency virus 1 in Ghana.

Eleven human immunodeficiency virus 1 (HIV-1) isolates from Ghanaian acquired immunodeficiency syndrome (AIDS) or AIDS-related complex (ARC) patients obtained by our serosurvey in 1986-1994 were genomically analyzed and phylogenetically compared with other known strains. A phylogenetic tree constructed by analyzing the env region indicated that heterogeneous HIV-1 strains were circulating in Ghana and the majority of them (9 of 11 isolates) belonged to clade (subtype) A which is now furiously epidemic in Africa. Another isolate (1 of 11) belonged to clade D, and the remaining one (1 of 11) belonged to "clade G". This "clade G" virus grouped by the env analysis belonged to clade A by its pol sequence, suggesting an A/G intersubtype recombinant. The characteristic sequences in the V3 tip which have not yet been reported were observed in these Ghanaian isolates, which should be taken into account for future vaccine programs.

PIP: The molecular epidemiology of HIV-1 in Ghana was investigated through genomic and phylogenetic analysis of isolates from 11 AIDS or AIDS-related complex patients obtained in 1986-94. A phylogenetic tree constructed by analyzing the env region indicated that heterogeneous HIV-1 strains are circulating in Ghana. 9 of the isolates belonged to clade A, 1 to subtype D, and 1 to "clade G"--an A/G intersubtype recombinant. The V3 loops of all isolates were composed of 35 amino acid residues--a characteristic not previously described. These molecular data on the genetic variability of the envelope glycoprotein of HIV-1 should be useful for future vaccine studies in West Africa.

Predominance of HIV-1 among patients with AIDS and AIDS-related complex in Ghana.

We determined the prevalence of HIV among AIDS and AIDS-Related Complex (ARC) patients seen within one year in two hospitals in southern Ghana. Subjects were screened by an ELISA procedure for anti-HIV antibodies. Specific identification of the HIV type was done with a particle agglutination (PA) kit. All PA-determined dual specimens were then confirmed by Western blotting and Pepti-Lav 1/2 monoepitope kit. Virus isolation was attempted from symptomatic patients by co-culturing patient peripheral blood monocyte cells (PBMCs) and CD4+ cell lines. PBMCs and HIV isolates were characterised by PCR. By ELISA, 43.5% of the subjects (253) had anti-HIV antibodies. Of these, 61 (24%) were HIV-1 positive and 42 (18.6%) were dually reactive by PA. However, only 19% were confirmed as true dually-infected cases by western blotting and Pepti-Lav through all 42 samples were HIV-1 positive on the two tests. No subject was infected with HIV-2 alone. Three viruses were isolated. By PCR two of them had both HIV-1 and HIV-2 proviral sequences while the third virus was HIV-1 only. HIV-1 prevalence now predominates over HIV-2 implying a switch in the HIV infection pattern in Ghana. Furthermore mixed infections exist. The predominance of HIV-1 infection in Ghana may indicate a similar trend in other parts of West Africa.

PIP: Recent studies have suggested that HIV-2 infection is becoming less prevalent in Ghana, while the prevalence of HIV-1 is increasing. To confirm such a modification in the HIV infection profile in Ghana, a 1-year serologic and molecular study was conducted among 253 patients from 2 hospitals in southern Ghana (Accra and Dzodze in the Volta region) with confirmed or suspected AIDS. All 253 serum specimens were screened with enzyme-linked immunosorbent assay (ELISA) and particle agglutination (PA); the 42 dually reactive specimens were subsequently confirmed by Western blot and Pepti-Lav tests. By ELISA, 110 samples (43.5%) were positive for anti-HIV antibodies; this rate was 39.2% in Accra and 81.0% in the Volta region. Of these, 61 (24.1%) were HIV-1 positive and 42 (18.6%) were dually reactive by PA. No case of HIV-2 alone was detected. Most dually reactive cases were a cross-reaction between genetically similar regions of the 2 HIV types. Only 19% of the 42 PA-diagnosed dually reactive specimens were confirmed by Western blot and Pepti-Lav as true cases of HIV-2 only infection, and all these specimens were strongly positive for anti-HIV-1 antibodies. 3 viruses were isolated. By polymerase chain reaction, 2 had both HIV-1 and HIV-2 proviral sequences, while the third was HIV-1 only. This study's findings provide support for the hypothesis that most individuals with antibodies to both HIV-1 and HIV-2 are probably infected with HIV-1 alone. Intensified population surveillance aimed at isolating more HIV strains in West Africa could reveal the true extent of HIV genomic variation and facilitate the design of more specific diagnostic kits.

Genetic and phylogenetic analysis of HIV type 1 env subtypes in Ghana, west Africa.

PIP: The authors examined HIV-1 genetic variation among 19 HIV-1-infected people of mean age 34.5 years living in Accra, Akwatia, Kumasi, and Ho, in Ghana. One person was of unknown origin. Blood samples were collected between December 1993 and January 1996. 16 of the HIV-1 specimens clustered with members of subtype A, but the clustering was not supported by 70% or more of the bootstrap tests. Two samples clustered with subtype D strains, supported by 92.5% of the bootstrap trees, and one sample clustered with subtype G strains, supported by 96.2% of the bootstrap trees. For the Ghanaian specimens belonging to subtype A, interhost distances at the nucleotide level averaged 14.9%, of range 7.83-20.9%. The interhost distance between the two subtype D samples was 8.2%. A cocirculation of subtypes A, D, and G was identified in Akwatia.^ieng

Isolation of simian immunodeficiency viruses from two sooty mangabeys in Côte d'Ivoire: virological and genetic characterization and relationship to other HIV type 2 and SIVsm/mac strains.

OBJECTIVE: To search for the presence of SIV in sooty mangabeys and other monkey species in Côte d'Ivoire, West Africa, and to compare viral isolates with HIV-2 strains from the same region. METHODS: Forty-three captive housed monkeys (28 African green monkeys, 6 sooty mangabeys, 6 baboons, and 6 patas monkeys) were tested for the presence of HIV and SIV antibodies. Virus was isolated from the peripheral blood lymphocytes of seropositive animals and from HIV-2 antibody-positive patients originating from Côte d'Ivoire, Ghana, Senegal, and Belgium. Viruses were characterized by Western blot and radioimmunoprecipitation assay. Proviral DNA was amplified by PCR, cloned, and sequenced to construct a phylogenetic tree. RESULTS: One African green monkey and three sooty mangabeys had antibodies that cross-reacted with HIV-2. From two mangabeys lentiviruses were isolated and designated as SIVsmCI2 and SIVsmCI8. Serological, virological, and sequence data showed that these isolates are members of the HIV-2/SIVsm/SIVmac group of primate lentiviruses. Furthermore, in the phylogenetic tree, these two new viruses form a distinct subgroup that is equidistant to the HIV-2 strains and the previously described SIVsm/SIVmac viruses. CONCLUSION: This study provides additional evidence that sooty mangabey monkeys can be infected with a lentivirus in their natural habitat. Within the SIVsm and SIVmac viruses extensive genetic variation is observed.