Separation of human immunodeficiency virus type 1 from motile sperm by the double tube gradient method versus other methods

OBJECTIVE

To compare a new sperm-processing device, utilizing a double tube and gradient, with other commonly used sperm-processing methods for their abilities to exclude human immunodeficiency virus type 1 (HIV-1) from the motile sperm fraction while retaining maximum sperm yield.

DESIGN

Laboratory experiments.

SETTING

Academic research environment.

PATIENT(S)

Healthy HIV-1 seronegative men between the ages of 25 and 55.

INTERVENTION(S)

Semen samples were spiked with HIV-1 (MN HIV-1 strain; range of concentrations: 10(-1)-10(6) TCID(50)) and subjected to one of the following sperm-processing methods: double sperm tube with discontinuous gradient of sperm separation medium formed inside (double tube gradient), conventional single tube gradient, swim-up or single tube gradient followed by swim-up (gradient/swim-up), which is the method currently used to minimize HIV-1 in semen used for assisted reproductive technology (ART) procedures. For the gradient techniques, Percoll, ISolate, and PureSperm sperm separation media were compared for efficacy of HIV-1 removal. The amount of HIV-1 remaining in the motile sperm pellet after processing was measured by reverse transcription-polymerase chain reaction (RT-PCR), NucliSens assay, or quantitative HIV-1 culture. A hemacytometer was used to microscopically assess motile sperm count.

MAIN OUTCOME MEASURE(S)

HIV-1 RNA copy number, decrease in HIV-1 TCID(50), motile sperm yield.

RESULT(S)

The double tube gradient technique was significantly better than all other methods in the removal of HIV-1 from the motile sperm fraction, and produced significantly higher sperm yields in comparison with the gradient/swim-up method.

CONCLUSION(S)

The double tube gradient technique is a relatively simple and effective method that reduces the risk of infection by HIV-1 while producing good sperm recovery.

Genetic characterization of equine arteritis virus during persistent infection of stallions

Equine arteritis virus (EAV) causes a persistent infection of the reproductive tract of carrier stallions. The authors determined the complete genome sequences of viruses (CW96 and CW01) that were present 5 years apart in the semen of a carrier stallion (CW). The CW96 and CW01 viruses respectively had only 85.6 % and 85.7 % nucleotide identity to the published sequence of EAV (EAV030). The CW96 and CW01 viruses had two 1 nt insertions and a single 1 nt deletion in the leader sequence, and a 3 nt coding insertion in ORF1a; thus their genomes included 12 708 nt as compared to the 12 704 nt in EAV030. Variation between viruses present in the semen of stallion CW and EAV030 was especially marked in the replicase gene (ORF1a and 1b), and the greatest variation occurred in the portion of ORF1a encoding the nsp2 protein. The ORFs 3 and 5, which respectively encode the GP3 and GP5 envelope proteins, showed greatest variation amongst ORFs encoding structural EAV proteins. Comparative sequence analyses of CW96 and CW01 indicated that ORFs 1a, 1b and 7 were highly conserved during persistent infection, whereas there was substantial variation in ORFs 3 and 5. Although the variation that occurs in ORF5 results in the emergence of novel phenotypic viral variants as determined by neutralization assay, all variants were neutralized by high-titre polyclonal equine antisera, suggesting that immune evasion is unlikely to be responsible for the establishment of persistent EAV infection of carrier stallions. Northern blot analyses of RNA extracted from cell culture propagated viruses isolated from 10 different persistently infected stallions failed to demonstrate any large genomic deletions, suggesting that defective interfering particles are also unlikely to be important in either the maintenance or clearance of persistent EAV infection of the reproductive tract of carrier stallions.

Bovine viral diarrhea virus in embryo and semen production systems

Although BVDV-free offspring have been produced from persistently infected bulls and heifers via advanced reproductive techniques, embryos and semen can potentially transmit the virus. Due to this potential for transmission, appropriate testing is necessary to ensure freedom of semen and embryos from BVDV. In the future, less constraining quality control measures may ensure freedom of embryos and semen from BVDV. These quality control measures require additional research to be validated.

Assisted reproduction in HIV and HCV infected men of serodiscordant couples

In serodifferent couples, there is a significant risk of sexual transmission of HIV, while the risk of transmitting HCV is minor. That said, the whole of the ejaculate is not necessarily infected and, therefore, hazardous. A careful dissection of its components by which motile sperm is separated and subsequently analyzed to verify the absence of viral elements could allow these couples a safer access to the reproductive process. The development in the field of assisted reproduction of new laboratory techniques and reliable tests for confirming the presence of both viruses in semen have led to the achievement of pregnancies while avoiding the infection of the seronegative partner and offspring. The system of detection is often performed by means of RT-PCR methods. These protocols are sensitive, but the presence of polymerase inhibitors in semen interferes with the reactions, yielding a high number of false negatives or undetermined results. HIV affects sperm quality only in the most advanced stages of the disease, while the fertility of asymptomatic or mild symptomatic patients is not affected by the disease. This review explores the possibilities offered by assisted reproduction and molecular biology techniques to HIV and/or HCV serodiscordant couples by which they may conceive children with the minimum risk.

Evidence of genotypic resistance diversity of archived and circulating viral strains in blood and semen of pre-treated HIV-infected men

OBJECTIVE

To study the genetic diversity of drug-resistant HIV strains present in blood and in semen, especially those archived in peripheral blood mononuclear cells (PBMC) and non-sperm cells (NSC).

METHODS

Paired blood and semen samples were collected from twenty heavily pre-treated HIV-infected men. HIV RNA in blood plasma (BP) and seminal plasma (SP), as well as proviral DNA in PBMC and NSC were quantified and used for resistance genotyping. Phylogenetic analysis of protease gene clones was used to explore the diversity of the viral quasi-species.

RESULTS

Median BP HIV RNA, PBMC proviral DNA, SP HIV RNA and non-sperm cell proviral DNA loads were respectively: 4.77, 3.65, 3.16 and 1.77 log10 copies per ml or per 10 cells. Resistant HIV strains were found in the BP and PBMC of all the patients, in the SP of 14 patients, and in the NSC of five patients. Overall, the blood and genital compartments exhibited different genotypic resistance patterns in six patients (30%), with additional resistance mutations in the semen of four patients. Phylogenetic analysis of clones of HIV protease gene showed that viral strains in SP originated not only from passive diffusion from BP, but also from local production in semen. The storage of archived proviruses differed according to the anatomic reservoir.

CONCLUSION

HIV resistant strains are frequent (70%) in the semen of heavily pre-treated men, and the diversity of genotypic resistance pattern confirms HIV compartmentalization. Thus, the risk of sexual transmission of resistant strains can only be partly predicted by standard tests applied to BP.

Analytical sensitivity of assays used for detection of bovine viral diarrhea virus in semen samples from the Southeastern United States

Bovine viral diarrhea virus (BVDV) is a significant pathogen that can be shed in the semen of infected bulls. Thus, screening for BVDV in semen of bulls is recommended prior to their entry into an artificial insemination center. No previous research has compared the analytical sensitivity of reverse transcription-nested polymerase chain reaction (RT-nPCR) and virus isolation assays for detection of BVDV in semen from an infected bull. Therefore, the goals of this research were to compare the analytical sensitivity of RT-nPCR and virus isolation assays for BVDV in semen and to apply these assays to determine the prevalence in the Southeastern United States of bulls that lack viremia yet shed BVDV in semen. Semen collected from a bull that was persistently infected with BVDV was serially diluted (1/10) in semen from uninfected bulls and frozen in liquid nitrogen as raw, partially extended or fully extended semen. Subsequently, samples of semen were assayed by virus isolation and RT-nPCR. Viral detection was more sensitive in extended semen samples than in raw semen samples and more sensitive by RT-nPCR than virus isolation. After this evaluation of analytical sensitivity, serum and semen were collected from 558 post-pubertal bulls in our region. These samples were tested for BVDV by virus isolation. Partially extended semen was also assayed for BVDV by RT-nPCR. All samples were negative by all assays for BVDV. The application of analytically sensitive assays reveals a very low prevalence (</=0.54%) of BVDV in semen from bulls in the Southeastern United States.

Viruses in Semen and Male Genital Tissues - Consequences for the Reproductive System and Therapeutic Perspectives

Sexually transmissible diseases such as AIDS have renewed the attention paid to viruses capable of infecting the male genital tract. The presence of viruses at this level may not only lead to their transmission and spread via semen but may also impact on male fertility and/or represent a potential cause of genital organ cancers. This review summarizes the currently available data on the various viruses identified in the human semen and male reproductive tract, their distribution in tissues and fluids, their possible cell targets and the functional consequences of their infectivity on the reproductive and endocrine systems. The use of medically assisted reproduction as a therapeutic tool in serodiscordant couples, as well as treatment strategies that need to be developed in order to eradicate these viruses from the male genital tract, are discussed.

Detection of chicken anemia virus DNA in embryonal tissues and eggshell membranes

Chicken infectious anemia virus (CIAV) is a ubiquitous and highly resistant virus of chickens that causes anemia and death in chicks less than 3 wk of age and immunosuppression in chickens older than 3 wk of age. The production of specific-pathogen-free eggs free of CIAV is essential for research and vaccine production. Currently, flocks are screened for CIAV by antibody tests to ensure freedom from CIAV infection. Recent evidence, however, indicates that chickens may carry and vertically transmit CIAV DNA independently of their antibody status. In this study, we tested embryos and eggshell membrane residues by nested polymerase chain reaction (PCR) as a sensitive method of detecting CIAV DNA. CIAV DNA could be detected in the blastodisks and semen obtained from antibody-positive and -negative chickens. Examination of different tissues between 18 and 20 days of incubation indicated that many but not all organs of individual embryos were positive. The lymphoid organs and gonads had the highest incidence of CIAV DNA, which was significantly different (P < 0.05) from the incidence in the liver. Eggshell membrane samples from embryos or newly hatched chicks were an excellent noninvasive source for the detection of CIAV DNA, identifying significantly more positive embryos than did pooled lymphoid organs. The use of dexamethasone injections as a method to improve the detection of carrier birds did not result in an increase of vertical transmission or cause seroconversion in the treated hens. A combination of testing eggshell membrane residues at hatch and periodic testing of blood DNA by nested PCR can be used to identify chickens carrying CIAV DNA and may be used to eradicate carrier birds.

Use of frozen semen to avoid human immunodeficiency virus type 1 transmission by donor insemination: a cost-effectiveness analysis

OBJECTIVE

Reappraisal of current guidelines mandating frozen-thawed semen.

DESIGN

Cost-effectiveness analysis comparing the use of frozen semen with the use of fresh semen from the same donors without a second antibody test.

SETTING

A Markov model computer simulation.

PATIENT(S)

A theoretical cohort of 80000 women whose husbands are azoospermic.

INTERVENTION(S)

Simulation with calculation of costs and payoffs.

MAIN OUTCOME MEASURE(S)

Total lifetime direct health care costs, costs per live birth, life expectancy, quality adjusted life years (QALY), marginal cost effectiveness (dollar/QALY).

RESULT(S)

If all 80000 women who undergo donor insemination in the United States each year chose to use fresh semen from donors screened according to the current practice guidelines but without semen cryopreservation, there would be 8881 more births and the mean cost per live birth would be US dollars 15501 less. One recipient would become infected with HIV-1 every 5.1 years, during which time over 180000 noninfected children would be born. The average life expectancy of recipients would be reduced by 2 days, but their quality-adjusted life expectancy would increase by over 1 month. Medicolegal costs to physicians would need to exceed US dollars 780 million per infection to equalize the cost effectiveness of the fresh and frozen policies.

CONCLUSION(S)

The guidelines should be revised to allow the use of fresh semen by informed recipients.

The first isolation of equine arteritis virus in Argentina

This paper describes the first isolation of equine arteritis virus (EAV) in Argentina. The virus was isolated from the semen of an imported seropositive stallion held in isolation at a breeding farm in Tandil in the Buenos Aires Province. In addition, viral nucleic acid was detected in seminal plasma using the reverse-transcription polymerase chain reaction. The isolated virus was propagated in cell cultures and confirmed as EAV by indirect immunofluorescence and virus neutralisation, using a serum specific for the reference Bucyrus strain of EAV. As far as the authors are aware, this is the first time that EAV has been isolated in South America. The equine industry is very important for Argentina and international movement of horses is very intensive. This finding may have effects on the international trade of horses and semen from Argentina.

Longitudinal comparison between plasma and seminal HIV-1 viral loads during antiretroviral treatment

This study was designed to investigate the impact of anti-retroviral therapy on both plasma and seminal HIV-1 viral loads and the correlation between viral loads in these compartments after treatment. Viral load, CD4+ and CD8+ T-cell counts were evaluated in paired plasma and semen samples from 36 antiretroviral therapy-naïve patients at baseline and on days 45, 90, and 180 of treatment. Slopes for blood and seminal viral loads in all treated patients were similar (p = 0.21). Median HIV-1 RNA titers in plasma and semen at baseline were 4.95 log10 and 4.48 log10 copies/ml, respectively. After 180 days of therapy, the median viral load declined to 3.15 log10 copies/ml (plasma) and 3.2 log10 copies/ml (semen). At this timepoint 22 patients presented HIV-1 viral load below 400 copies/ml in either plasma or semen, but only 9 had viral loads below 400 copies/ml in both compartments.

Temporal localization of porcine reproductive and respiratory syndrome virus in reproductive tissues of experimentally infected boars

Porcine reproductive and respiratory syndrome virus (PRRSV) has been reported to be shed in the semen of infected boars. To determine whether the reproductive tissues could be a persistent source of virus and the possible origin of PRRSV found in semen of infected boars, 20 PRRSV-seronegative boars were intranasally inoculated with 5 x 10(6) median tissue culture infective doses (TCID50) of PRRSV and necropsied at different times post-inoculation (p.i.) from Day 2 to Day 37 p.i. Blood samples were collected before experimental inoculation, at necropsy and at different times p.i. At necropsy, epididymal semen and reproductive tissues were collected and the presence of the virus determined by virus isolation. The infection of the boars was demonstrated by the isolation of the virus from the sera of all inoculated boars and by seroconversion. PRRSV was detected in serum samples from Day 2 to Day 23 p.i., although the viremic period was largely dependent on the individual response to infection. Viral replication was proven within different reproductive tissues from Day 2 to Day 23 p.i., being most consistently found in the epididymus. In addition, PRRSV was isolated in semen from Day 4 to Day 10 p.i. The correlation of a diminished viremia and the inability to isolate PRRSV from semen or reproductive tissues may be due to one of two possibilities. First, viremia is responsible for most of the virus isolated from reproductive tissues due to the movement of PRRSV-infected cells out of the blood and into the tissues. Second, viremia may initially seed the reproductive tissues with PRRSV, and then the virus is produced into the reproductive tract and shed into semen at low levels.

Use of an internal standard in a TaqMan® nested reverse transcription-polymerase chain reaction for the detection of bovine viral diarrhoea virus

The aim of this study was to improve molecular methods for the detection of bovine viral diarrhoea virus (BVDV). A single-tube nested reverse-transcriptase polymerase chain reaction (nRT-PCR) employing the 5'-3'-exonuclease assay (TaqMan) system was optimised for use with bulk milk, semen and whole blood samples. An artificial template (mimic) was engineered to provide in-tube validation of negative samples by demonstrating the absence of substances inhibitory to RT or PCR. This mimic was constructed by disrupting the BVDV amplicon at the TaqMan probe site by inserting a 295bp fragment of human genomic DNA. The mimic amplicon was discriminated from the BVDV RT-PCR products using a second TaqMan probe, with a different fluorochrome specific for the inserted DNA. This new method was more sensitive than BVDV antigen ELISA methods and the existing RT-PCR method used in the laboratory for detection of BVDV in bulk milk. Furthermore, RNA extracted by robotic methods has proved suitable for use in this assay. This TaqMan nRT-PCR will be a valuable method for the detection of BVDV in a variety of biological matrices including milk and semen.

Bovine herpesvirus 5 (BoHV-5) in bull semen: amplification and sequence analysis of the US4 gene

Bovine herpesvirus type 5 (BoHV-5), which is potentially neuropathogenic, was detected in clinical samples of bovine semen, both directly and after isolation in cell culture, using a nested PCR system for amplifying the US4 gene. Nucleotide sequences generated from the amplicons were analysed and deposited at GenBank (NCBI, Bethesda, MD, USA) under the accession numbers AF298174 and AF330157. Alignment of these sequences and previously deposited sequences of BoHV-1 and BoHV-5 showed 82% and 98% similarity, respectively. The bulls, which were maintained at an artificial insemination centre, had presented no clinical signs, indicating that bovine semen should be screened for BoHV-5 to prevent transmission of the virus.

Drug-resistant HIV-1 in the semen of men receiving antiretroviral therapy with acute sexually transmitted infections

Sexually transmitted infections may enhance the sexual transmission of HIV-1. It is possible that loss of virological control in patients with such infections receiving antiretroviral therapy (ART) may even facilitate the transmission of drug-resistant HIV. We have recently demonstrated that in those on maximally suppressive ART this effect is reduced. We have examined the virus obtained from the blood plasma and seminal plasma of six HIV-1-infected men receiving poorly suppressive ART with acute urethritis for the presence of drug resistance-associated mutations. In four men with gonorrhoea the blood and seminal plasma HIV-1 had mutations conferring reduced susceptibility to one or more available drugs. In one of these men the viral load of drug-resistant virus in seminal plasma was 20-fold higher during gonorrhoea than following antibiotic treatment, with no change in blood plasma viral load. We conclude that in the presence of suboptimal ART, sexually transmitted infections may enhance the spread of drug-resistant HIV-1.

Risk of cytomegalovirus transmission by cryopreserved semen: a study of 635 semen samples from 231 donors

BACKGROUND

The hypothetical responsibility of sperm donation in cytomegalovirus (CMV) transmission to recipients and precautions to prevent this transmission are widely discussed. The aim of this French CECOS Federation study was to evaluate both the reality and the importance of the CMV risk due to donor sperm and the relevance of measures used to screen it.

METHODS

We conducted a prospective multicentric study. CMV was detected by rapid and conventional cultures and by PCR in the frozen sperm of donors who met the normal criteria required of semen donors, irrespective of their CMV serological status.

RESULTS

635 samples from 231 donors (39.4% IgG(+)) were obtained and tested by culture; 551 samples from 197 donors were also tested by PCR. From those samples, 0.78% were culture(+), 1.57% culture(+) and/or PCR(+); 3.3% of seropositive donors and 0.72% of initially seronegative donors were culture(+), but in the latter seroconversion occurred during the quarantine period; of the 197 PCR-tested donors, 3.5% (6.2/1.7) were PCR(+), 3.3% (5.3/1.45) culture(+) and/or PCR(+). PCR(+) samples can be culture(-) and vice versa. The most strongly positive sample corresponded to an initially seronegative donor.

CONCLUSION

The best strategy to prevent potential CMV risk is to test donors for CMV IgG and IgM antibody at the outset and after a 6 month period of quarantine and to reject initially IgM seropositive donors or donors who seroconvert during the quarantine period.

Transmission, acute HIV-1 infection and the quest for strategies to prevent infection

By the acute stage of HIV-1 infection, the immune system already faces daunting challenges. Research on mucosal barriers and the events immediately after heterosexual transmission that precede this acute stage could facilitate the development of effective microbicides and vaccines.

Simultaneous detection and differentiation between porcine circovirus and porcine parvovirus in boar semen by multiplex seminested polymerase chain reaction

A multiplex seminested polymerase chain reaction (PCR) was developed for the simultaneous detection and differentiation among porcine circovirus 1 (PCV1), PCV2, and porcine parvovirus (PPV) from boar semen. Primers of PCV1, PCV2 and PPV were specific and did not react with other viruses respectively. Twenty (20.4%) and 42 (42.9%) out of 98 whole semen samples were found to be positive for PCV and PPV using multiplex conventional and seminested PCR, respectively. When the separated fractions of PCV or PPV-contaminated semen were analyzed using multiplex seminested PCR, PCV and PPV DNA were found to be present mainly in the seminal fluid and nonsperm cell fractions. This multiplex seminested PCR assay was sensitive, rapid and a good alternative method for the detection and differentiation of these viruses in boar semen.

[Evaluation of the interest of semen culture before cryoconservation]

OBJECTIVES

French guidelines recommend screening all patients for virus infection prior to cryopreservation of their semen. In case of viral risk, the use of specific high secure CBS straws is recommended. The objective of this work was to evaluate the microbiological risk by testing all semen samples before cryopreservation.

PATIENTS AND METHODS

Fifty one patients underwent a semen culture before cryopreservation.

RESULTS

The fifty one patients were classed into 3 groups following semen culture results: group I: negative culture (39/51, 76.47%), group II: positive culture with microbiological contamination (7/51, 13.73%) and group III: positive culture with pathogen (5/51, 9.8%). For 3 patients of the latter group, we tested a three-layer density gradient to eliminate bacteria before Assisted Reproductive Techniques.

DISCUSSION AND CONCLUSIONS

This paper discusses the risks related to microbiological contamination and the options available in this case.

Detection of herpes simplex virus, cytomegalovirus, and Epstein-Barr virus in the semen of men attending an infertility clinic

OBJECTIVE

To investigate the prevalence of herpes simplex virus (HSV), cytomegalovirus (CMV), and Epstein-Barr virus (EBV) in the semen of men with fertility problems.

DESIGN

A descriptive clinical study.

SETTINGS

Outpatient infertility clinic of a private hospital.

PATIENT(S)

One hundred thirteen men attending an infertility clinic in Athens.

INTERVENTION(S)

Semen samples were collected by masturbation.

MAIN OUTCOME MEASURE(S)

Detection of HSV, CMV, and EBV in semen by a nested polymerase chain reaction technique. Complete spermogram including sperm count, motility, pH, viscosity, and morphology.

RESULT(S)

Viral DNA was detected by the nested polymerase chain reaction technique in 64 (56.6%) of 113 semen samples. Specifically, HSV DNA was detected in 56 (49.5%) semen samples, EBV DNA in 19 (16.8%) semen samples, and CMV DNA in 8 (7.1%) semen samples. HSV was significantly related to low sperm count and poor motility. In contrast, CMV and EBV did not show any association with sperm concentration and motility.

CONCLUSION(S)

Herpes simplex virus seems to play a significant role in male infertility, and its early detection by the nested polymerase chain reaction technique will permit successful antiviral therapy to increase the possibility for fertility restoration and long-term protection of the sperm quality. Finally, the detection of herpes viruses within semen will allow better control of the transmission of these viruses.

Assisted reproduction techniques for HIV serodiscordant couples: 18 months of experience

BACKGROUND

Assisted reproduction techniques can minimize the risk of infection and treat possible sterility associated with serodiscordant couples.

METHODS

We assessed the efficacy of these techniques in 57 couples in which at least one partner had human immunodeficiency virus (HIV-1) infection that was currently under control (47 men and 10 women). The semen of seropositive men was prepared and tested for viruses. Assisted reproduction techniques included intrauterine insemination (IUI), IVF and especially ICSI, with ovarian stimulation that used a long agonist protocol and recombinant FSH. Embryos were transferred on day 3 after oocyte retrieval.

RESULTS

For couples with seropositive men, five IUI and 49 IVF or ICSI attempts were perfomed, whilst for seropositive women these numbers were three IUI and 12 IVF or ICSI. No pregnancy occurred following the eight IUI trials. Seroconversion was not observed in any partners of seropositive men. Efficacy of treatment for these couples with ICSI was good, the clinical pregnancy rate per embryo transfer was 48.8%. The results for seropositive women were disappointing, with a clinical pregnancy rate per embryo transfer of 9.1%. Fourteen babies from 47 treated couples have so far been born and no pregnancies from IUI.

CONCLUSIONS

Assisted reproduction techniques and particularly ICSI provide HIV-1-seropositive men with a safe and highly effective means of fathering children. These techniques may be less effective for seropositive women.

Addition of treatment for trichomoniasis to syndromic management of urethritis in Malawi: a randomized clinical trial

BACKGROUND

Male urethritis is generally treated syndromically, but failure of empirical treatment is common.

GOAL

The study goal was to evaluate the addition of metronidazole to the syndromic management of urethritis in Malawi in a randomized clinical trial.

STUDY DESIGN

Men with urethritis were randomized to receive either 2 g of metronidazole by mouth or placebo, in addition to standard care for urethritis (i.e., a single intramuscular dose of 240 mg gentamicin and 100 mg doxycycline twice daily for 7 days). The primary endpoints of the study included measurement of the effects of treatment on Trichomonas vaginalis, signs and symptoms of urethritis, and the concentration of HIV RNA in semen in dually infected subjects.

RESULTS

The overall prevalence of T vaginalis was 17.3% (71/411), and treatment with metronidazole cleared 95% of culture-positive infections, compared with 54% clearance among men receiving placebo (P = 0.006). Prevalence of persistent urethritis was observed in approximately 16% of both groups at the end of 1 week (29/179 of those receiving metronidazole versus 29/187 in the placebo group; P = 0.86). For a subset of HIV-infected men with trichomoniasis, the seminal plasma HIV RNA concentration was higher than in a group of HIV-positive control subjects (median copies/mL:35,000 vs. 1800 P = 0.06) [correction].

CONCLUSION

In areas with a high prevalence of trichomoniasis, the addition of metronidazole to the syndromic management of male urethritis can eliminate infection with T vaginalis and may help to reduce the transmission of HIV. Such treatment should be strongly considered as part of empirical therapy for urethritis in men in Malawi and places where T vaginalis infection in men is common.

Estimating correlation by using a general linear mixed model: evaluation of the relationship between the concentration of HIV-1 RNA in blood and semen

Estimating the correlation coefficient between two outcome variables is one of the most important aspects of epidemiological and clinical research. A simple Pearson's correlation coefficient method is usually employed when there are complete independent data points for both outcome variables. However, researchers often deal with correlated observations in a longitudinal setting with missing values where a simple Pearson's correlation coefficient method cannot be used. General linear mixed models (GLMM) techniques were used to estimate correlation coefficients in a longitudinal data set with missing values. A random regression mixed model with unstructured covariance matrix was employed to estimate correlation coefficients between concentrations of HIV-1 RNA in blood and seminal plasma. The effects of CD4 count and antiretroviral therapy were also examined. We used data sets from three different centres (650 samples from 238 patients) where blood and seminal plasma HIV-1 RNA concentrations were collected from patients; 137 samples from 90 different patients without antiviral therapy and 513 samples from 148 patients receiving therapy were considered for analysis. We found no significant correlation between blood and semen HIV-1 RNA concentration in the absence of antiviral therapy. However, a moderate correlation between blood and semen HIV-1 RNA was observed among subjects with lower CD4 counts receiving therapy. Our findings confirm and extend the idea that the concentrations of HIV-1 in semen often differ from the HIV-1 concentration in blood. Antiretroviral therapy administered to subjects with low CD4 counts result in sufficient concomitant reduction of HIV-1 in blood and semen so as to improve the correlation between these compartments. These results have important implications for studies related to the sexual transmission of HIV, and development of HIV prevention strategies.

Dynamics of viral load rebound in plasma and semen after stopping effective antiretroviral therapy

A rebound in the plasma and seminal viral load was detected in 12 patients after the interruption of effective highly active antiretroviral therapy. The viral rebound was generally higher in plasma, although the highest level observed during interruption was higher in semen in two patients. The reintroduction of therapy was followed by an overall decrease in HIV-RNA in plasma and semen. One to 2 months after restarting treatment, four out of seven patients showed undetectable HIV-RNA in semen.