CD4- and CD3-T lymphocyte reference values of immunocompetent urban and rural subjects in an African nation.

Studies on the reference values of CD4 and CD3 T cells in healthy individuals have continued to gain significance because of the importance of these immunological markers in the initiation of combination antiretroviral therapy (cART). The aim of the present study was to determine and compare the reference values of CD4 and CD3 T cells in urban and rural Nigerians who were human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV) negative. After ethical clearance and informed consent, 1123 subjects who met the inclusion criteria [mean age = 24.4 (± 11.2) years] were recruited in this study. Blood samples were analysed using the BD FACScount cytometer according to the manufacturer's instructions. Of the overall 1123 subjects, reference means of CD4, CD3 and CD4/CD3 ratio were 1030 ± 367, 1757 ± 609 cells/µl and 0.59 ± 0.08, respectively. Five hundred and fifty-one (49.1%) were an urban population with the mean CD4, CD3 and CD4/CD3 T cell ratio of 1032 ± 369, 1761 ± 612 cells/µl and 0.59 (±0.08), respectively. The remaining 572 (50.9%) were of a rural population with the mean CD4, CD3 and CD4/CD3 T cell ratio of 1028 ± 459, 1753 ± 958 cells/µl and 0.59 ± 0.13, respectively. Subjects with higher CD4 and CD3 T cells were more likely to be female than male (P < 0.05). There was no significant difference between the T cell values of the two populations (P > 0.05). Our findings provide new insight in the CD4 and CD3 T cell reference values of Nigerians.

Quantification of human immunodeficiency virus-1 viral load using nucleic acid sequence-based amplification (NASBA) in north central Nigeria.

BACKGROUND: Viral load (VL) quantification is considered an integral part of the standard care in human immunodeficiency virus (HIV) infected individuals but in Nigeria as in most of sub-Saharan Africa, this has not reached the majority ofpatients. METHODS: We report the first field application of the NucliSens EasyQ HIV-1 platform for the real time quantification of HIV-1 VL combining NASBA amplification and real time detection with molecular beacons among HIV-1 infected individuals in north central Nigeria where the predominant HIV-1 subtypes are CRF02_AG and G. CD4+ counts were enumerated using a fluorescence-activated cell sorter system. RESULTS: Of one hundred and forty nine (n=149) plasma sample from patients with mean age of 32 years and made up of 77 males and 72 females, fifty {n=50 (37.9%); 28 males and 22 females} had VLs below the lower detection limit (LDL=25 IU/ml) set by the assay while eighty-two {n=82 (62.1%); 39 males and 43 females} had VL levels above the LDL. Furthermore, 13 of 82 (15.9%) patients with viral loads above the LDL had VLs between 26-1000 IU/ml while 69 (84.1%) had VLs of 1001-2,400,000 IU/ml. 17 (11.4%) of the samples could not be analyzed due to poor viral amplification. Among individuals with both CD4+ and VL results (n=56), those with CD4+ of 1-418 cell/microl presented with higher VL usually above 45,000 IU/ml when compared with those with CD4+ of over 500 cell/microl. CONCLUSION: Our findings highlight the pattern, usefulness and feasibility ofVL quantification by NucliSens EasyQ in monitoring HIV-1 patients in Nigeria.

Inverted CD4+/CD8+ ratio associated with AIDS event and death in HIV-1 infected individuals in Nasarawa State, Nigeria.

The current guidelines for the use of antiretroviral therapy in Nigeria places emphasis on the use of CD4+ enumeration to take decision of initiating antiretroviral therapy and HIV disease monitoring. CD4+ counts are known to be inherently inconsistent and therefore could be misleading. This study was undertaken to analyze the CD4+/CD8+ ratio vis-à-vis CD4+ in HIV-1 infected individual in North Central Nigeria and to correlate these immunological parameters to AIDS event and death in relation to gender and age of patients. Cell counts were carried out using a Fluorescence Activated Cell Sorter (FACS) that quantifies CD4+ and CD8+ T lymphocytes as absolute numbers of lymphocytes per microL of blood and the CD4+/CD8+ T lymphocyte ratio recorded in an automated fashion. A total of 290 HIV-1 positive persons were enrolled for this study. The median CD4+/CD8+ ratio were 0.05, 0.27, 0.64 in patients with CD4+ counts of < 50, 51-200, > 350 respectively. CD4+/ CD8+ of 0.05 and 0.27 were corresponding predictors of AIDS-related event and death. Patients with > 0.64 are predictive of better disease prognosis and low progression to AIDS. The CD4+/CD8+ were minimally higher in female patients with a median CD4+/CD8 ratio of 0.27. The age distribution of our patients at point of first entry was not found to influence CD4+/CD8+ ratios. These findings provide basic and critical CD4+/CD8+ cut-off values in predicting HIV disease progression and an alternative to absolute CD4+ counts at predicting the onset of HIV related disease. These data are useful to determine when intervention with antiretroviral therapy is needed and to determine the likelihood of virological failure.

High prevalence of hepatitis B virus among female sex workers in Nigeria.

Hepatitis B virus (HBV) infection is endemic in Nigeria and constitutes a public health menace. The prevalence of HBV infection in many professional groups has been described in Nigeria. However, literature on HBV infection among female sex workers (FSW) in Nigeria is scanty. FSW in Nigeria are not subjected to a preventive control of HBV infection. This study assesses the extent of spread of HBV among FSW in Nigeria. Seven hundred and twenty (n = 720) FSW (mean age = 26.7 years) were tested for hepatitis B surface antigen (HBsAg) by a double antibody sandwich ELISA method. The overall HBV prevalence among the FSW was 17.1%. FSWs between the ages of 31-35 year (20.5%) and those with 'age-at-first-sex' below 10 years of age (28%) were most affected. This high prevalence of a vaccine preventable disease is unacceptable, therefore, vaccination of this high risk HBV reservoir group should be considered worthwhile.

High prevalence of hepatitis B virus among female sex workers in Nigeria / Alta prevalência de hepatite pelo vírus B entre trabalhadoras do sexo feminino na Nigéria

Hepatitis B virus (HBV) infection is endemic in Nigeria and constitutes a public health menace. The prevalence of HBV infection in many professional groups has been described in Nigeria. However, literature on HBV infection among female sex workers (FSW) in Nigeria is scanty. FSW in Nigeria are not subjected to a preventive control of HBV infection. This study assesses the extent of spread of HBV among FSW in Nigeria. Seven hundred and twenty (n = 720) FSW (mean age = 26.7 years) were tested for hepatitis B surface antigen (HBsAg) by a double antibody sandwich ELISA method. The overall HBV prevalence among the FSW was 17.1 percent. FSWs between the ages of 31-35 year (20.5 percent) and those with 'age-at-first-sex' below 10 years of age (28 percent) were most affected. This high prevalence of a vaccine preventable disease is unacceptable, therefore, vaccination of this high risk HBV reservoir group should be considered worthwhile.

A hepatite pelo vírus B (HBV) é infecção endêmica na Nigéria e constitui problema de saúde pública. A prevalência da infecção HBV em muitos grupos profissionais foi descrito na Nigéria. No entanto, a literatura da infecção HBV entre trabalhadoras do sexo feminino (FSW) na Nigéria é escasso. FSW na Nigéria não são submetidas a um controle preventivo de infecção de HBV. Este estudo avalia a extensão da disseminação de HBV entre FSW na Nigéria. Setecentos e vinte (n = 720) FSW (média de idade = 26,7 anos) foram testadas para antígeno de superfície da hepatite B (HBsAg) pelo método ELISA usando sandwich de duplos anticorpos. A prevalência total de HBV entre o FSW foi 17,1 por cento. FSWs entre as idades de 31-35 anos (20,5 por cento) e abaixo de 10 anos de idade (28 por cento) foram mais afetadas. Esta alta prevalência de doença evitável pela vacinação é inaceitável, portanto, vacinação deste grupo de alto risco de HBV deve ser considerada fundamental.

A review of the disease burden, impact and prevention of typhoid fever in Nigeria.

BACKGROUND: Typhoid fever is still a common infection in many parts of the world, especially in developing countries where sanitation and water supply are a common problem. A recent study placed the disease burden at 21650 974 illnesses and 216510 deaths during 2000. The infection is a major cause of morbidity and mortality in Nigeria. OBJECTIVE: This review set out to present in one concise volume a review of the major findings from published articles on the burden and impact of typhoid fever in Nigeria to aid easy reference for researchers. It highlights the disease burden, the different diagnostic methods and their sensitivities, complications, treatment methods as well as the various preventive measures including the use of typhoid vaccine in the control of the disease. METHODS: Several published articles covering a period of 40 years were accessed different journals and reviewed, and their major findings presented in this review. RESULTS: The disease burden from typhoid fever in Nigeria is still high with associated serious complications, which in most cases have been managed effectively with the use of potent antibiotics and surgical intervention. However, the typhoid problem has been compounded by the emergence and circulation of multi-drug resistant strains of the organism being sensitive only to the newer generation antibiotics. CONCLUSION: Typhoid fever remains a major public health problem in Nigeria. The infection however can be prevented by good sanitation, improving good water supply, the provision of proper sewage disposal system, as well as the effective use of the available typhoid vaccines. The government and people of Nigeria should rise up to the challenge of stamping out this ugly trend.

A review of the epidemiology, prevention and treatment of human immunodeficiency virus infection in Nigeria

In order to amalgamate research findings on HIV/AIDS in Nigeria as well as the trend of the infection in a concise manner, we reviewed published articles on the HIV/AIDS situation in Nigeria. We categorized this review into several subheadings. The HIV prevalence rate has continued to rise steadily from less than 0.1 percent in 1987, to 5.8 percent in 2001, with a slight decrease in 2003 to 5.0 percent. Although the knowledge about HIV and its mode of transmission is widespread, it is however disheartening to note that this did not result into appreciable attitudinal change and behavior modification among Nigerians. Both HIV-1 and HIV-2 have been identified in Nigeria, with HIV-1 being the predominant type. Furthermore, several subtypes like subtypes A, B, C, G and J have been identified in Nigeria, with several recombinant forms like the CRF02_AG; the major ones being A, G and CRF02_AG. HIV-infected patients in Nigeria are also co-infected with other viral and bacterial infections, the commonly reported ones being co infections with hepatitis B and C. Although treatment of infected patients has increased recently, more effort is needed, especially in the area of patients monitoring, to maximize the benefits of ART in Nigeria. Finally, Nigeria has made appreciable efforts in vaccine development and candidate HIV DNA vaccines have been developed utilizing the sequences from predominant subtypes, and these candidates have been shown to be immunogenic in animal models. It is therefore clear that only the integration of prevention and antiretroviral research programmes into a coherent programme that is needed to address the public health needs that HIV/AIDS crisis represents for Nigeria.

The role of triple infection with hepatitis B virus, hepatitis C virus, and human immunodeficiency virus (HIV) type-1 on CD4+ lymphocyte levels in the highly HIV infected population of North-Central Nigeria.

We set out to determine the seroprevalence of hepatitis B and C among human immunodeficiency virus type-1 (HIV-1) infected individuals in North-Central Nigeria to define the influence of these infections on CD4+ lymphocytes cells among our patients as access to antiretroviral therapy improves across the Nigerian nation. The CD4+ values of 180 confirmed HIV-1 infected individuals were enumerated using a superior fluorescence-activated cell sorter system. These patients were tested for the presence of hepatitis B surface antigen and anti-hepatitis C virus (HCV) using third generation enzyme-linked immunosorbent assays. Fifty (27.8%) patients had active hepatitis B virus (HBV) infection while 33 (18.3%) tested positive for anti-HCV antibody. Of these infections, 110 (61.1%), 37 (20.6%), and 20 (11.1%) had HIV only, HBV/HIV-only, and HCV/HIV-only respectively. A HBV/HCV/HIV coinfection prevalence of 7.2% (13 patients) was recorded. Patients coinfected with HIV/HBV/HCV appeared to have lower CD4+ counts (mean = 107 cells/microl; AIDS defining) when compared to HBV/HIV-only (mean = 377 cells/microl), HCV/HIV-only (mean = 373 cells/microl) and patients with mono HIV infection (mean = 478 cells/microl). Coinfection with HBV or HCV is relatively common among HIV-infected patients in Nigeria and should be a big consideration in the initiation and choice of therapy.

The role of triple infection with hepatitis B virus, hepatitis C virus, and human immunodeficiency virus (HIV) type-1 on CD4+ lymphocyte levels in the highly HIV infected population of North-Central Nigeria

We set out to determine the seroprevalence of hepatitis B and C among human immunodeficiency virus type-1 (HIV-1) infected individuals in North-Central Nigeria to define the influence of these infections on CD4+ lymphocytes cells among our patients as access to antiretroviral therapy improves across the Nigerian nation. The CD4+ values of 180 confirmed HIV-1 infected individuals were enumerated using a superior fluorescence-activated cell sorter system. These patients were tested for the presence of hepatitis B surface antigen and anti-hepatitis C virus (HCV) using third generation enzyme-linked immunosorbent assays. Fifty (27.8 percent) patients had active hepatitis B virus (HBV) infection while 33 (18.3 percent) tested positive for anti-HCV antibody. Of these infections, 110 (61.1 percent), 37 (20.6 percent), and 20 (11.1 percent) had HIV only, HBV/HIV-only, and HCV/HIV-only respectively. A HBV/HCV/HIV coinfection prevalence of 7.2 percent (13 patients) was recorded. Patients coinfected with HIV/HBV/HCV appeared to have lower CD4+ counts (mean = 107 cells/æl; AIDS defining) when compared to HBV/HIV-only (mean = 377 cells/æl), HCV/HIV-only (mean = 373 cells/æl) and patients with mono HIV infection (mean = 478 cells/æl). Coinfection with HBV or HCV is relatively common among HIV-infected patients in Nigeria and should be a big consideration in the initiation and choice of therapy.

A review of the epidemiology, prevention and treatment of human immunodeficiency virus infection in Nigeria.

In order to amalgamate research findings on HIV/AIDS in Nigeria as well as the trend of the infection in a concise manner, we reviewed published articles on the HIV/AIDS situation in Nigeria. We categorized this review into several subheadings. The HIV prevalence rate has continued to rise steadily from less than 0.1% in 1987, to 5.8% in 2001, with a slight decrease in 2003 to 5.0%. Although the knowledge about HIV and its mode of transmission is widespread, it is however disheartening to note that this did not result into appreciable attitudinal change and behavior modification among Nigerians. Both HIV-1 and HIV-2 have been identified in Nigeria, with HIV-1 being the predominant type. Furthermore, several subtypes like subtypes A, B, C, G and J have been identified in Nigeria, with several recombinant forms like the CRF02_AG; the major ones being A, G and CRF02_AG. HIV-infected patients in Nigeria are also co-infected with other viral and bacterial infections, the commonly reported ones being co infections with hepatitis B and C. Although treatment of infected patients has increased recently, more effort is needed, especially in the area of patients monitoring, to maximize the benefits of ART in Nigeria. Finally, Nigeria has made appreciable efforts in vaccine development and candidate HIV DNA vaccines have been developed utilizing the sequences from predominant subtypes, and these candidates have been shown to be immunogenic in animal models. It is therefore clear that only the integration of prevention and antiretroviral research programmes into a coherent programme that is needed to address the public health needs that HIV/AIDS crisis represents for Nigeria.

A Tat subunit vaccine confers protective immunity against the immune-modulating activity of the human immunodeficiency virus type-1 Tat protein in mice.

The rational design of new therapies against HIV-1 necessitates an improved understanding of the mechanisms underlying the production of ineffective immune responses to HIV-1 in most infected individuals. This report shows that the CD8(+) T cell responses to gp120 were greatly diminished in mice vaccinated with a bicistronic gp120-Tat DNA vaccine, compared with those induced by a DNA vaccine encoding gp120 alone. The CD8(+) T cell responses induced by the latter included strong gp120-specific IFN-gamma secretion and protective antiviral immunity against challenge by a vaccinia-env pseudotype. The degree to which Tat influenced CD8(+) T cell responses depended on the bioactivity of Tat. Thus, a bicistronic DNA vaccine that expresses gp120 and a truncated Tat defective for LTR activation elicited strong IFN-gamma -secreting CD8(+) T cell responses to gp120 but conferred only marginal protection against the vaccinia-env challenge. The effect of Tat was completely blocked, however, by immunization with inactivated Tat protein before vaccination with the bicistronic gp120-Tat DNA vaccine.

Molecular surveillance of HIV-1 field strains in Nigeria in preparation for vaccine trials.

We conducted a national molecular epidemiologic survey of HIV-1 strains in Nigeria to determine the most prevalent subtype(s) for use in developing candidate vaccines. A total of 230 HIV-1-positive blood samples collected from 34 of the 36 Nigerian states were analyzed by our modified env gp41-based heteroduplex mobility assay (HMA) and/or gp41 sequencing and analysis. Overall, 103 (44.8%) were subtype A, 125 (54.3%) were subtype G, one (0.4%) was subtype C, and one (0.4%) was subtype J, and one (0.4%) was unclassifiable. To further characterize Nigerian viruses to aid in strain selection for candidate vaccines, one gp41 subtype G and five gp41 subtype A strains were selected for full envelope sequencing. The one subtype G sequence had consistent phylogenies throughout gp160, using programs to detect recombination. However, all five sequences that were primarily subtype A in gp41 were found to be recombinant viruses. Two of the five (40%) were A/G/J mosaics with common breakpoints. The remaining three gp160 recombinants all had their own unique break points: two A/? and one A/?/G, however, all five had the majority of their mosaic breakpoints occurring in gp41. None of the five were consistent with the circulating recombinant form (CRF)02_AG strain previously reported to be prevalent in West Africa. In conclusion, we showed a clear dominance and widespread distribution of gp41 subtypes A and G in fairly equal proportions, suggesting that vaccines designed for use in this geographic locale should incorporate the gene(s) of both subtypes. However, appreciating the magnitude of diversity of HIV-1 strains in Nigeria may require sequencing and analysis of longer gene regions for the identification of prevalent or emerging CRFs.

Development of an env gp41-based heteroduplex mobility assay for rapid human immunodeficiency virus type 1 subtyping.

The gp120 region of the human immunodeficiency virus type 1 (HIV-1) envelope (env) gene exhibits a high level of genetic heterogeneity across the group M subtypes. The heteroduplex mobility assay (HMA) has successfully been used to assign subtype classifications, but C2V5 primers often fail to amplify African strains. We developed an env gp41-based HMA for which the target sequence is amplified with highly conserved gp41 primers, known to efficiently amplify nucleic acids from HIV-1 group M, N, and O viruses. By using gp41 from a new panel of reference strains, the subtype assignments made by our modified HMA were concordant with those obtained by sequencing and phylogenetic analysis of 34 field strains from 10 countries representing subtypes A to G. Testing of field strains from Nigeria further demonstrated the utility of this modified assay. Of 28 samples, all could be amplified with gp41 primers but only 17 (60.7%) could be amplified with the standard C2V5 primers. Therefore, gp41-based HMA can be a useful tool for the rapid monitoring of prevalent subtypes in countries with divergent strains of circulating HIV-1.

Genetic variability of HIV-1 protease from Nigeria and correlation with protease inhibitors drug resistance.

In Nigeria, the most populous country in Africa, the characterization of HIV-1 strains has been limited. In this study we evaluated the genetic diversity of the protease coding region, one of the anti-retroviral therapy target, and investigated the presence of mutations related to resistance to HIV protease inhibitors. We analyzed samples collected during 1996 and all patients were anti-retroviral drug naïves. Ten samples were evaluated by sequencing of the protease gene. The majority, 80%, were classified as subtype A and the two others were unclassified-divergent strains, something in between A and G subtypes. The gag region from these outliners were sequenced and the phylogenetic analysis classified them as subtype G. The protease amino acid consensus sequence of the Nigerian subtype A are in complete agreement with the consensus A differing from the USA subtype B consensus in 10 positions (L10V, I13V, K14R, I15V, K20I, M36I, R41K, P63L, H69K and L89M). The secondary substitutions associated with protease inhibitor resistance were observed in all Nigerian sequences at the positions L10V, M36I and L89M. The majority of sequence variation was concentrated in the interval between aminoacids 70-90 where the protease substrate binding region is located.

Frequency of human toxocariasis in Jos, Plateau State, Nigeria

The enzyme-linked immunosorbent assay (Elisa) was used to examine sera of 104 children and adults in Jos, Plateau State, Nigeria for anti-toxocaral antibodies, out of which 31 (29.8) were reactive. The seropositive rates were 30.4 for adults, 29.6 for children, 34 for females and 25.9 for males. However, the differences were not significant by age and sex. A highly significant association (p < 0.001) was observed between seropositivity and geography but none between seropositivity and dog ownership (p > 0.05).

Frequency of human toxocariasis in Jos, Plateau State, Nigeria.

The enzyme-linked immunosorbent assay (Elisa) was used to examine sera of 104 children and adults in Jos, Plateau State, Nigeria for anti-toxocaral antibodies, out of which 31 (29.8%) were reactive. The seropositive rates were 30.4% for adults, 29.6% for children, 34% for females and 25.9% for males. However, the differences were not significant by age and sex. A highly significant association (p < 0.001) was observed between seropositivity and geography but none between seropositivity and dog ownership (p > 0.05).

Response to heterologous leishmanins in cutaneous leishmaniasis in Nigeria--discovery of a new focus.

A pilot study was undertaken to preliminary illustrate the leishmanin skin test (LST) positivity to distinct antigen preparations (derived from promastigote of either Leishmania major or L. amazonensis, or pooled L. mexicana, L. amazonensis and L. guyanensis) in cutaneous leishmaniasis (CL) patients and healthy subjects living in two endemic foci in Nigeria. The study was designed to provide insights into whether cross-species leishmanin, such as that prepared from New World Leishmania could be useful to detect cases of Old World leishmanial infection and to compare the results with LST using L. major-derived leishmanin. The overall LST positivity in individuals from Keana tested with the cross-species leishmanin was 28.7% (27/94), while the positivity rate in the subjects from Kanana tested with the same leishmanin was 54.5% (6/11). Lower positivity values were obtained when L. major (12.5%; 11/88) or L. amazonensis (15.8%; 9/57) was tested as antigen in grossly comparable populations. Moreover, the pooled leishmanin identified most of the subjects (13/14; 92.9%) with active or healed CL, and the maximum reaction sizes were found among positive subjects in this group. No healthy controls (10 total) showed specific DTH response. The LST was useful for assessing the prevalence of subclinical infection and for measuring CL transmission over time. We report for the first time the occurrence of CL in Kanana village of Langtang South local government area of Plateau State.