Mark Rayfield

Perinatal Transmission of the Human Immunodeficiency Virus Type 1 to Infants of Seropositive Women in Zaire

To examine perinatal transmission of the human immunodeficiency virus type 1 (HIV-1) in Zaire, we screened 8108 women who gave birth at one of two Kinshasa hospitals that serve populations of markedly different socioeconomic status. For up to one year, we followed the 475 infants of the 466 seropositive women (5.8 percent of those screened) and the 616 infants of 606 seronegative women matched for age, parity, and hospital. On the basis of clinical criteria, 85 of the seropositive women (18 percent) had the acquired immunodeficiency syndrome (AIDS). The infants of seropositive mothers, as compared with those of seronegative mothers, were more frequently premature, had lower birth weights, and had a higher death rate in the first 28 days (6.2 vs. 1.2 percent; P less than 0.0001). The patterns were similar at the two hospitals. Twenty-one percent of the cultures for HIV-1 of 92 randomly selected cord-blood samples from infants of seropositive women were positive. T4-cell counts were performed in 37 seropositive women, and cord blood from their infants was cultured. The cultures were positive in the infants of 6 of the 18 women with antepartum T4 counts of 400 or fewer cells per cubic millimeter, as compared with none of the infants of the 19 women with more than 400 T4 cells per cubic millimeter (P = 0.02). One year later, 21 percent of the infants of the seropositive mothers had died as compared with 3.8 percent of the control infants (P less than 0.001), and 7.9 percent of their surviving infants had AIDS. We conclude that the mortality rates among children of seropositive mothers are high regardless of socioeconomic status, and that perinatal transmission of HIV-1 has a major adverse effect on infant survival in Kinshasa.

Use of the polymerase chain reaction for early detection of the proviral sequences of human immunodeficiency virus in infants born to seropositive mothers

Abstract The early diagnosis of infection with human immunodeficiency virus (HIV) in infants born to infected mothers is essential for early treatment, but current tests cannot detect HIV infection in newborns because of the presence of maternal antibodies. We used the polymerase chain reaction, a new technique that amplifies proviral sequences of HIV within DNA, to detect HIV infection in peripheral-blood mononuclear cells obtained from infants of seropositive women during the neonatal (age less than 28 days) and postneonatal periods. In blood obtained during the neonatal period, the polymerase chain reaction was positive in five of seven infants in whom the acquired immunodeficiency syndrome (AIDS) later developed (a mean of 9.8 months after the test). The test was also positive in one of eight newborns who later had nonspecific signs and symptoms suggestive of HIV infection (mean follow-up, 12 months). No proviral sequences were detected in neonatal samples from nine infants who remained well (mean fol...

Protease sequences from HIV-1 group M subtypes A-H reveal distinct amino acid mutation patterns associated with protease resistance in protease inhibitor-naive individuals worldwide.

BackgroundAlthough numerous mutations that confer resistance to protease inhibitors (PRI) have been mapped for HIV-1 subtype B, little is known about such substitutions for the non-B viruses, which globally cause the most infections. ObjectivesTo determine the prevalence of PRI-associated mutations in PRI-naive individuals worldwide. DesignUsing the polymerase chain reaction, protease sequences were amplified from 301 individuals infected with HIV-1subtypes A (79), B (95), B’ (19), C (12), D (26), A/E (23), F (26), A/G (11), and H (3) and unclassifiable HIV-1 (7). Amplified DNA was directly sequenced and translated to amino acids to analyze PRI-associated major and accessory mutations. ResultsOf the 301 sequences, 85% contained at least one codon change giving substitution at 10, 20, 30, 36, 46, 63, 71, 77, or 82 associated with PRI resistance; the frequency of these substitutions was higher among non-B (91%) than B (75%) viruses (P < 0.0005). Of these, 25% carried dual and triple substitutions. Two major drug resistance-conferring mutations, either 20M or 30N, were identified in only three specimens, whereas drug resistance accessory mutations were found in 252 isolates. These mutations gave distinct prevalence patterns for subtype B, 63P (62%) > 77I (19%) > 10I/V/R (6%) = 36I (6%) = 71T/V (6%) > 20R (2%), and non-B strains, 36I (83%) > 63P (17%) > 10I/V/R (13%) > 20R(10%) > 77I (2%), which differed statistically at positions 20, 36, 63, 71, and 77. ConclusionsThe high prevalence of PRI-associated substitutions represent natural polymorphisms occurring in PRI-naive patients infected with HIV-1 strains of subtypes A−H. The significance of distinct mutation patterns identified for subtype B and non-B strains warrants further clinical evaluation. A global HIV-1 protease database is fundamental for the investigation of novel PRI.

Dual and Recombinant Infections: An Integral Part of the HIV-1 Epidemic in Brazil

We systematically evaluated multiple and recombinant infections in an HIV-infected population selected for vaccine trials. Seventy-nine HIV-1 infected persons in a clinical cohort study in Rio de Janeiro, Brazil, were evaluated for 1 year. A combination of molecular screening assays and DNA sequencing showed 3 dual infections (3.8%), 6 recombinant infections (7.6%), and 70 (88.6%) infections involving single viral subtypes. In the three dual infections, we identified HIV-1 subtypes F and B, F and D, and B and D; in contrast, the single and recombinant infections involved only HIV-1 subtypes B and F. The recombinants had five distinct B/F mosaic patterns: Bgag-p17/Bgag -p24/Fpol/Benv , Fgag-p17/Bgag -p24/Fpol/Fenv , Bgag-p17/B-Fgag -p24/Fpol/Fenv , Bgag-p17/B-Fgag -p24/Fpol/Benv , and Fgag-p17/B-Fgag -p24/Fpol/Fenv . No association was found between dual or recombinant infections and demographic or clinical variables. These findings indicate that dual and recombinant infections are emerging as an integral part of the HIV/AIDS epidemic in Brazil and emphasize the heterogenous character of epidemics emerging in countries where multiple viral subtypes coexist.

Prevalence of Human Immunodeficiency Virus Type 1 p24 Antigen in U.S. Blood Donors — An Assessment of the Efficacy of Testing in Donor Screening

Abstract Background. We performed a multicenter study in 1989 to determine whether screening whole-blood donors for human immunodeficiency virus type 1 (HIV-1) p24 antigen would improve transfusion safety by identifying carriers of the virus who are seronegative for HIV-1 antibody. Methods. More than 500,000 donations were tested at 13 U.S. blood centers with test kits from two manufacturers. Units found repeatedly reactive were retested in a central laboratory; if the results were positive, they were confirmed by a neutralization assay. A subgroup of units was also tested for HIV-1 by the polymerase chain reaction. Selected donors confirmed or not confirmed as having p24 antigen were contacted for follow-up interviews to identify risk factors and undergo retesting for HIV-1 markers. Results. Positive tests for p24 antigen were confirmed by neutralization in five donors (0.001 percent of all donations tested), all of whom were also positive for HIV-1 antibody and HIV-1 by polymerase chain reaction. Three ...

Identification of Single and Dual Infections with Distinct Subtypes of Human Immunodeficiency Virus Type 1 by Using Restriction Fragment Length Polymorphism Analysis

The simultaneous presence of multiple HIV-1 subtypes has become common in communities with the growth of the pandemic. As a consequence, the potentiality for an increased frequency of HIV-1 mixed infections caused by viruses of distinct subtypes could be expected. Thus, there is a need to estimate the prevalence and geographic distribution of infections caused by viruses of a singular subtype as well as coinfections caused by two or more HIV-1 strains of distinct subtypes. To address this need, we have developed a genetic method based on restriction fragment length polymorphism (RFLP) to screen for these two types of infections within infected populations. In this assay, restriction enzymes may be used to predict the phylogroup of HIV-1 infected samples. A 297 bp pol fragment spanning the entire viral protease gene and a 311 bp fragment of the p24 gag region are used for this analysis. The viral regions are amplified by nested PCR using DNA templates from uncultured peripheral blood mononuclear cells (PBMC) or virus culture. Classification of HIV-1 strains to well defined subtypes B, D, F, and A/C is done by sequential endonuclease restriction analysis of a PCR amplified-protease gene followed by analysis of the p24 gag region. The electrophoretic migration patterns visualized by ethidium bromide staining or by radiolabeled probes are then determined on a 10% polyacrylamide gel. In infections caused by viruses of a singular subtype, a single restriction pattern is detected, whereas in multiple infections caused by two or more viral strains of different subtypes, the combination of different digestion patterns are observed in infected individuals. Using this methodology we have screened for genetic variations in HIV-1 proviral DNA from thirty-three Brazilian samples. Our RFLP procedure classified thirty-two samples as single infections caused by viruses of subtypes B (31) and F (1), and one sample as dual infection caused by distinct viral strains. Subsequent sequence and phylogenetic analysis of the viral protease gene in lymphocytes of all these patients confirmed our RFLP findings in single infections, and demonstrated the existence of two distinct HIV-1 strains of subtypes F and D in a patient which lymphocytes showed the simultaneous presence of two different digestion patterns. As up to now, single infections caused by subtype D variants were not identified in Brazil, our data provide the first evidence of subtype D HIV-1 in this country. Because sequencing of HIV proviral DNA is not particularly practical for large-scale molecular epidemiological studies, the protease/gag-based RFLP screening method will be useful to predict the phylogroup of HIV-1, and to identify multiple infections caused by HIV-1 strains of distinct subtypes. We believe that this information is crucial for both evaluation of the HIV-1/AIDS pandemic and intervention strategies.

HIV-1 subtypes among blood donors from Rio de Janeiro, Brazil.

The prevalence of HIV infection in Brazil is one of the highest in the world. In addition, transfusion-transmitted HIV accounts for 2.3% of all AIDS cases in Brazil. The objective of this study was to evaluate genetic diversity and distribution of HIV-1 strains circulating in the blood-donor population. We characterized 43 seropositive blood units collected from volunteer blood donors residing throughout Rio de Janeiro, Brazil. Viral RNA was extracted from plasma, reverse transcribed, and amplified by nested polymerase chain reaction (PCR) using HIV group M degenerate primers. Genetic heterogeneity was evaluated by direct automated cycle sequencing of the following gene fragments: gag p24 (399 bp), env C2V3 (345 bp), and env gp41 (369 bp). Phylogenetic analysis reflected the complexity of the Brazilian HIV epidemic: the majority of specimens, 33 of 43 (76.7%) were subtype B, and 6 of 43 (14%) were subtype F. The remaining 4 samples (9.3%) involved potential mosaic viruses of subtypes B and F or B and D. This survey is the first to document HIV-1 genetic variation in the Brazilian blood-donor population.

A molecular epidemiologic survey of HIV in Uganda.

Objective:Previous data, based on a small sampling of convenience, reported subtypes A, B, C, D, and G in Uganda, but neither the extent nor the proportion of these subtypes could be evaluated. To establish correctly the prevalence and distribution of HIV-1 subtypes, we analysed viral clades in 739 HIV-1-seropositive specimens from different areas of Uganda. Methods:Blood specimens from 1100 patients were collected in five districts of Uganda. Within this collection, 929 HIV-1-seroreactive samples underwent analysis of viral DNA, and 739 were selected for further subtyping in env or pol regions. Results:Using a combination of subtype A- and D-specific probes to C2–V3 region and DNA sequencing, HIV-1 env subtypes were determined in 594 specimens: 341 were of subtype A (57.4%), 250 of subtype D (42.1%), and three of subtype C (0.5%). Sixty-two samples showed reactivity with both probes, suggesting potential mixed infections, cross-reactivity to probes, or possibly other subtypes. Subsequent sequence analysis of 19 randomly selected specimens revealed subtypes A (n = 4), D (n = 12), and C (n = 3). Sequence analysis of the 27 samples chosen from the remaining 83 samples, which could be amplified only with viral gp41 or protease gene primers, classified them as subtypes A (n = 13) and D (n = 14). No significant clinical, demographic, or geographic differences were found between HIV-1 infections with viruses of subtypes A and D, despite considerable genetic diversity within these clades. Conclusions:This is the first major population-based study of the prevalent HIV-1 strains in an African country selected for vaccine trials. The subtyping methods we describe should be of use to investigators seeking to conduct large-scale screening for HIV variants in other populations.

Horizontal and Vertical Transmission of Human Immunodeficiency Virus Type 1 Dual Infections Caused by Viruses of Subtypes B and C

This article describes a case of horizontal (heterosexual) and subsequent vertical (mother to infant) transmission of 2 human immunodeficiency viruses type 1 (HIV-1) subtypes. Dual infection in a husband, his wife, and their child was initially detected by use of a restriction fragment length polymorphism assay of the proviral protease in peripheral blood mononuclear cells. The simultaneous presence of highly similar sets of HIV-1 subtypes B and C infecting the 3 family members was confirmed by DNA sequence analysis of pol, gag, and env genes. These data, together with available epidemiologic information, may indicate that the husbands high-risk sexual behavior was the source of dual infections. Because his wife did not report such activities, it was likely that he passed HIV-1 strains to his spouse, who subsequently transmitted them to their child.

Integrated Disease Investigations and Surveillance planning: a systems approach to strengthening national surveillance and detection of events of public health importance in support of the International Health Regulations

The international community continues to define common strategic themes of actions to improve global partnership and international collaborations in order to protect our populations. The International Health Regulations (IHR[2005]) offer one of these strategic themes whereby World Health Organization (WHO) Member States and global partners engaged in biosecurity, biosurveillance and public health can define commonalities and leverage their respective missions and resources to optimize interventions. The U.S. Defense Threat Reduction Agency’s Cooperative Biologica Engagement Program (CBEP) works with partner countries across clinical, veterinary, epidemiological, and laboratory communities to enhance national disease surveillance, detection, diagnostic, and reporting capabilities. CBEP, like many other capacity building programs, has wrestled with ways to improve partner country buy-in and ownership and to develop sustainable solutions that impact integrated disease surveillance outcomes. Designing successful implementation strategies represents a complex and challenging exercise and requires robust and transparent collaboration at the country level. To address this challenge, the Laboratory Systems Development Branch of the U.S. Centers for Disease Control and Prevention (CDC) and CBEP have partnered to create a set of tools that brings together key leadership of the surveillance system into a deliberate system design process. This process takes into account strengths and limitations of the existing system, how the components inter-connect and relate to one another, and how they can be systematically refined within the local context. The planning tools encourage cross-disciplinary thinking, critical evaluation and analysis of existing capabilities, and discussions across organizational and departmental lines toward a shared course of action and purpose. The underlying concepts and methodology of these tools are presented here.