Genotypic analysis of the protease and reverse transcriptase of HIV type 1 subtype C isolates from antiretroviral drug-naive adults in Malawi.

The protease (PR) and reverse transcriptase (RT) regions of HIV-1 isolates from 21 antiretroviral (ARV)-naive Malawian adults were sequenced and analyzed to determine the prevalence of drug resistance-associated mutations in this population. Phylogenetic analysis confirmed that all isolates grouped with HIV-1 subtype C, the predominant subtype in Malawi. No major mutations associated with resistance to PR inhibitors (PIs), nucleoside RT inhibitors (NRTIs), or nonnucleoside RT inhibitors (NNRTIs) were found. In contrast, accessory mutations were found in the protease region at positions 10, 20, 36, 63, 77, and 93, and in the RT region at positions 118, 211, and 214. Further studies will be needed to determine the clinical impact of these polymorphisms on viral susceptibility to existing antiretroviral drugs.

Driver's license and voter registration lists as population-based sampling frames for rural African Americans.

PURPOSE: To compare coverage of a state driver's license list and county voter registration lists as frames for sampling rural African Americans. METHODS: Name, birth date, sex, and county were extracted from records for all 18--59 year-old African Americans residing in eight rural North Carolina counties and listed in the North Carolina Driver license file [obtained as a SAS dataset from the University of North Carolina (UNC) Highway Safety Research Center] and in machine-readable text files of registered voters (obtained from county boards of elections). Files were edited, merged, and matched by last name and date of birth to produce three files for each five-year age group, sex, and county: 1) persons listed only in the driver's file; 2) persons listed only in the voter's file; and 3) persons listed in both. RESULTS: The median percentages of unique persons found only on the driver's list, only on the voter's list, and on both lists were 54%, 17%, and 30% men, and 35%, 25%, and 41% women, respectively. CONCLUSIONS: The driver's list provided better coverage than did voter registration lists. Federal legislation that prohibits states from releasing driver's license lists for use in surveys removes a valuable resource for population-based research.

Social context of sexual relationships among rural African Americans.

BACKGROUND: Reasons for the strikingly increased rates of HIV and other sexually transmitted infections (STIs) among African Americans in the rural Southeastern United States remain unclear. Investigators have devoted little attention to the potential influence of the social and economic context on sexual behaviors. GOAL: To examine the potential influence of these contextual factors on behaviors that promote the transmission of STIs. STUDY DESIGN: Focus group interviews in which African Americans from rural North Carolina discussed life in their communities and contextual factors affecting sexual behavior. RESULTS: Respondents reported pervasive economic and racial oppression, lack of community recreation, boredom, and resultant substance abuse. Many perceived a shortage of black men because of their higher mortality and incarceration rates compared with whites, and believed this male shortage to be partly responsible for the concurrent sexual partnerships that they perceived as widespread among unmarried persons. CONCLUSION: Contextual features including racism, discrimination, limited employment opportunity, and resultant economic and social inequity may promote sexual patterns that transmit STIs.

Hepatitis E virus seroprevalence in children living in rural Ghana.

Large outbreaks of hepatitis E virus have been reported in warm climates with poor sanitation although it exists in endemic form in these areas too. This oro-fecally transmitted infection has been described mainly in adults with very little data from children. This study looked at seroprevalence in children resident in a rural district in Ghana with very little pipe-borne water supply. Sera from 803 randomly selected pupils aged 6-18 years were evaluated for anti-HEV. The overall seroprevalence was 4.4% with seroprevalence increasing from 1% in 6-7 year olds to 8.1% in 16-18 year olds. Females had a significantly higher seroprevalence than males. Anti-seroprevalence was also not influenced by the presence of hepatitis B and C virus markers. Anti-HEV seroprevalence was however, far lower than suspected seroprevalence of hepatitis A virus which is also transmitted oro-fecally. The short life of anti-HEV may be responsible for this low seroprevalence.

Risk factors for horizontal transmission of hepatitis B virus in a rural district in Ghana.

Most hepatitis B virus (HBV) infections in sub-Saharan African infants and children are acquired through horizontal transmission, but the exact mechanisms of spread have not been documented. The authors conducted a study in rural Ghana which determined seroprevalence in a probability sample of 1,385 individuals of all ages, and evaluated risk factors for horizontal transmission of HBV in a subsample of 547 children aged 1-16 years who were not hepatitis B surface antigen (HBsAg) carriers. Most residents in this district live in compounds which typically contain 2-4 households each. Overall prevalence of HBV seropositives (any HBV marker) was 74.7% (95% confidence interval (CI) 72.5%-76.9%). Prevalence of HBsAg was 20.9% (95% CI 18.8%-23.1%). The data suggest a continuous nonuniform acquisition of HBV infection with advancing age predominantly through horizontal transmission in childhood, with the household, rather than the domestic compound, being the primary place for transmission. The behaviors most strongly associated with prevalence of HBV were sharing of bath towels (OR = 3.1, 95% CI 2.1-4.5), sharing of chewing gum or partially eaten candies (OR = 3.4, 95% CI 2.3-5.0), sharing of dental cleaning materials (OR = 2.5, 95% CI 1.3-4.6), and biting of fingernails in conjunction with scratching the backs of carriers (OR = 2.5, 95% CI 1.6-4.3).

PIP: Most hepatitis B virus (HBV) infections in sub-Saharan African infants and children are acquired through horizontal transmission. Findings are reported from a study conducted in rural Ghana to measure seroprevalence in a probability sample of 1385 people of all ages, and evaluate risk factors for the horizontal transmission of HBV in a subsample of 547 children aged 1-16 years who were not hepatitis B surface antigen (HBsAg) carriers. Most residents in the sample area live in compounds which typically contain 2-4 households each. The overall prevalence of HBV seropositives was 74.7% and the prevalence of HBsAg was 20.9%. These data suggest a continuous nonuniform acquisition of HBV infection with advancing age mainly through horizontal transmission in childhood, with the household, rather than the domestic compound, being the main place for transmission. The sharing of bath towels, sharing of chewing gum or partially eaten candies, sharing of dental cleaning materials, and biting of fingernails together with scratching the backs of carriers are the behaviors found to be most strongly associated with HBV prevalence.

Biomarkers of essential fatty acid consumption and risk of prostatic carcinoma.

Animal studies have suggested that omega-6 fatty acids found in vegetable oils may promote prostate cancer. Our goal was to use erythrocyte membrane and adipose tissue fatty acid composition as biomarkers to investigate whether essential fatty acids modulated prostate cancer risk. An outpatient clinic-based study of 89 cases and 38 controls was conducted in North Carolina between July 1989 and December 1991. Cases were recruited from a university-based urology outpatient clinic. Eligible cases were more than 45 years of age and had histological confirmation of a prostate cancer diagnosis within 1 year of entry into the study. Controls were histologically confirmed free of prostate cancer. Erythrocyte membranes from venous blood and adipose tissue fatty acids from s.c. fat samples were analyzed in batches using capillary gas chromatography. Unconditional logistic regression analysis was used to calculate odds ratios for the association of each fatty acid with prostate cancer while controlling for potential confounders. Linoleic acid consumption was positively associated with prostate cancer risk. The odds ratios comparing the first and fourth quartiles of linoleic acid consumption were 3.54 (95% confidence interval, 1.0-12.53) with P trend < 0.04 for erythrocyte membranes, and 2.47 (95% confidence interval, 0.66-9.26) with P trend < 0.08 for adipose tissue. These data suggest that linoleic acid consumption may increase prostate cancer risk, which is consistent with results from animal experiments. Linoleic acid is found in vegetable oils used in cooking and in cereals, snack foods, and baked goods. Our data failed to demonstrate consistently a protective effect of marine omega-3 fatty acids on prostate cancer.

Prevalence studies of GB virus-C infection using reverse transcriptase-polymerase chain reaction.

Among the three recently described GB viruses (GBV-A, GBV-B, and GBV-C), only GBV-C has been linked to cryptogenic hepatitis in man. Because of the limited utility of currently available research tests to determine antibody response to GBV-C proteins, the prevalence of GBV-C RNA in human sera was studied using reverse transcription-polymerase chain reaction (RT-PCR). The prevalence of GBV-C is higher among volunteer blood donors with elevated serum alanine aminotransferase (ALT) levels (3.9%) than among volunteer blood donors with normal ALT levels (0.8%). Higher rates were also noted among commercial blood donors (12.9%) and intravenous drug users (16.0%). GBV-C was frequently detected in residents of West Africa, where the prevalence was > 10% in most age groups. Approximately 20% of patients diagnosed with either acute or chronic hepatitis C virus (HCV) were found to be positive for GBV-C RNA. In addition, GBV-C RNA sequences were detected in individuals diagnosed with non-A-E hepatitis, with clinical courses ranging from mild disease to fulminant hepatitis. Fourteen of sixteen subjects with or without clinically apparent hepatitis were positive for GBV-C RNA more than 1 year after the initial positive result.

Seroepidemiological survey of hepatitis B and C virus infections in Ghanaian children.

The seroprevalences of hepatitis B virus (HBV) and hepatitis C virus (HCV) markers were evaluated in a random sample of 803 children attending school in Ashanti-Akim North district in Ghana in order to gain a better understanding of transmission patterns of these viruses, particularly horizontal transmission of HBV. This rural district is typical of 70% of the Ghanaian population. The overall seroprevalence of at least one marker of HBV infection was 61.2%, with rates increasing from 48% to 80% between the ages of 6-18 years (P < 0.001). The overall HBsAg seroprevalence was 15.8%, with the proportion of HBsAg positives amongst those with anti-HBc increasing from 39.3% in 6-7-year-olds to 51.8% in 12-13-year-olds. It appears that horizontal transmission during this age period was accompanied by a high rate of HBsAg carriage. Among those infected but not carriers, i.e., those HBsAg negative and anti-HBc positive, > 50% lacked detectable levels of anti-HBs, an unusual pattern of convalescent immune response to HBV. The overall seroprevalence of anti-HCV was 5.4% and did not differ significantly by age or gender. Anti-HCV seroprevalence was not associated with the presence of any HBV marker. A better understanding of the unusually high prevalences of HBV and HCV infections demonstrated in this population is likely to influence vaccination and blood transfusion policies and to stimulate further evaluations of these infections and their vehicles of spread in highly endemic regions such as sub-Saharan Africa.

Correlation between biomarkers of omega-3 fatty acid consumption and questionnaire data in African American and Caucasian United States males with and without prostatic carcinoma.

Results from animal studies suggest that omega-3 fatty acids from marine sources are protective against cancer. To determine whether adipose tissue and erythrocyte membrane fatty acid composition could serve as biomarkers of essential fatty acid consumption in subjects with prostate cancer, we compared fish consumption, which was estimated using a food frequency survey, to the omega-3 fatty acid content of adipose tissue and erythrocyte membranes. The study was conducted using 127 men who had undergone a prostate biopsy. All subjects were recruited from a university hospital urology clinic. African Americans comprised 23% of the subjects, and 70% were diagnosed with prostate cancer. We found a correlation of 0.44 with 95% confidence intervals (CIs) = 0.29-0.57 between reported fish consumption and the omega-3 fatty acid eicosapentaenoic acid composition in erythrocyte membranes and 0.38 with 95% CI = 0.21-0.53 when the dietary survey was compared to eicosapentaenoic acid in adipose tissue. The survey/biomarker correlations in cases were not significantly different from the correlations in controls. The study had 90% power to detect a 0.35 difference between correlations. These results suggest that the presence of prostate cancer does not affect the adipose tissue or erythrocyte membrane biomarkers of fatty acid consumption, and that erythrocyte membranes are as useful as biomarkers as is adipose tissue. Our findings corroborate previous studies that found that tissue biomarkers can reflect past fatty acid consumption and support the use of biomarkers in case-control studies using cancer patients.