Prevalence of antibodies to herpes simplex virus types 1 and 2 in pregnant women, and estimated rates of infection

High silent prevalence of human herpesvirus 1 (HSV-1) infection affecting the indigenous reservation of the municipality of Dourados, Central-West Brazil

BACKGROUND

The indigenous population located in the central region of Brazil, is the second largest in terms of population size in the country. The Indigenous Reserve of Dourados has risk factors that increase the vulnerability of the indigenous population to infectious diseases, especially Human alphaherpesvirus (HSV-1), a neglected disease with high prevalence in priority populations in developing countries. The virus can also cause many more severe diseases, including widespread neonatal infections, herpetic keratitis, and herpes encephalitis, which can be fatal if left untreated. We estimated the prevalence of anti-HSV-1 antibodies and correlated it with the demographic and behavioral characteristics of the Indigenous population of the Jaguapirú and Bororó villages (Dourados, Mato Grosso do Sul (MS), Brazil).

METHODS

Our approach was cross-sectional. From March 2017 to November 2018. Using anti-HSV-1 (Gg1) IgM and anti-HSV-1 (gG1) IgG Euroimmun and the detection and quantification of HSV-1 viral load in plasma samples, through real-time PCR. The maps were constructed using QGIS and the statistical analyses using R Studio software.

RESULTS

A total of 1138 individuals (> 18 years old) were enrolled. The prevalence of anti-HSV-1 IgM and IgG were 20% and 97.5%, respectively. The prevalence of anti-HSV-1 antibodies for IgG was higher in both sexes. Anti-HSV-1 IgM antibodies were present in 17.1%, 21.2%, 12.5%, and 22% of the participants with urinary problems, genital wounds, genital warts, and urethral discharge, respectively. Real-time PCR was used for confirmatory testing; HSV-1 DNA was detected in 25.6% (54/211) of anti-HSV1 IgM-positive samples. Viral loads ranged from 5.99E + 02 to 3.36E + 13.

CONCLUSIONS

The seroprevalence of HSV-1 IgM and detection of HSV-1 DNA in the Indigenous population confirmed high silent prevalence. Furthermore, the seroprevalence of HSV-1 in the Indigenous population was higher than that reported in the general adult Brazilian population. Various socioeconomic factors, drug use, and health and sexual behaviors could contribute to the facilitation of HSV-1 transmission in the Indigenous population. Our results may help develop culturally appropriate intervention programs that eliminate health access barriers and improve the implementation of public health policies aimed at promoting information regarding the prevention, treatment, and control of HSV-1 infection in Brazilian Indigenous populations.

DNA from multiple viral species is associated with Alzheimer's disease risk

INTRODUCTION

Multiple infectious agents, including viruses, bacteria, fungi, and protozoa, have been linked to Alzheimer's disease (AD) risk by independent lines of evidence. We explored this association by comparing the frequencies of viral species identified in a large sample of AD cases and controls.

METHODS

DNA sequence reads that did not align to the human genome in sequences were mapped to viral reference sequences, quantified, and then were tested for association with AD in whole exome sequences (WES) and whole genome sequences (WGS) datasets.

RESULTS

Several viruses were significant predictors of AD according to the machine learning classifiers. Subsequent regression analyses showed that herpes simplex type 1 (HSV-1) (odds ratio [OR] = 3.71, p = 8.03 × 10-4) and human papillomavirus 71 (HPV-71; OR = 3.56, p = 0.02), were significantly associated with AD after Bonferroni correction. The phylogenetic-related cluster of Herpesviridae was significantly associated with AD in several strata of the data (p < 0.01).

DISCUSSION

Our results support the hypothesis that viral infection, especially HSV-1, is associated with AD risk.

Prevalence of herpes -, measles morbillivirus-, parvovirus B19 - and rubella viruses immunoglobulin G among women with chronic hepatitis B of reproductive age in Denmark: A cross-sectional study

OBJECTIVES

The aim of this study was to investigate whether the seroprevalence of IgG antibodies against seven viruses (cytomegalovirus, herpes simplex virus 1&2, measles morbillivirus, parvovirus B19, rubella, and varicella-zoster virus), which can potentially compromise maternal and fetal wellbeing, differs based on country of origin among women with chronic hepatitis B (CHB).

METHOD

This study was a single-center, hospital-based cross-sectional study. The study included women with CHB 15-45 years of age, included in the Danish Database for Hepatitis B and C. Seroprevalence estimates were calculated with a 95% confidence interval and were compared between age groups, regions of origin, and to the general population.

RESULTS

177 women were included in the study. Overall, the seroprevalences of antibodies were similar among women with CHB with origin outside Denmark and compared to the general population in Denmark, but there was a notable difference in the seroprevalence of antibodies against herpes simplex 2 between women from Africa (37.1% CI 95% 22.0;55.1) and women from the Middle East (2.5% CI 95% 0.1;14.7).

CONCLUSION

Women with CHB whose origin is outside Denmark do not appear to differ, based on origin, or be at greater risk of acquiring these viruses during pregnancy than their Danish counterparts.

Seroepidemiology of herpes simplex virus type 1 and 2 in northern iran

BACKGROUND

Herpes simplex virus (HSV) type 1 and 2 are common infectious agents worldwide. Data on prevalence of HSV-1 and HSV-2 infection are limited in Asia, especially in Iran. The aim of this study was to determine the seroprevalence of HSV type 1 and 2 based on age, gender, marital status, education, living area, job, symptoms and history of disease variables.

METHODS

The study population included 800 randomly selected persons from laboratories in Gilan Province, Iran, from 2010 to 2011. Demographic data gathered by a well-designed questionnaire and for serological studies, blood samples were collected and centrifuged. ELISA HSV-1, 2 and HSV-2 specific ELISA kits were used to determine IgG type specific antibodies in sera samples. Person's chi-square test was applied to compare HSV-1 and HSV-2 seropositivities.

RESULTS

HSV-1 and HSV-2 IgG antibodies were positive in 467 (58.4%) and 28 (3.5%) subjects, respectively. There was significant correlation between age, marital status, job, symptoms, history of disease and HSV seroprevalence (P<0.05).

CONCLUSION

Our findings were in agreement with prior studies in which HSV-1 infections was more prevalent than HSV-2 and seropositivity increased with age.

Deciphering the epidemic synergy of herpes simplex virus type 2 (HSV-2) on human immunodeficiency virus type 1 (HIV-1) infection among women in sub-Saharan Africa

BACKGROUND

Herpes Simplex Virus Type 2 (HSV-2) is highly prevalent in regions disproportionately affected by the human immunodeficiency virus (HIV-1) epidemic. The objective of our study was to identify the risk factors of HSV-2 and HIV-1 infections and to examine the association between the two infections.

METHODS

The study participants were recruited through a community based cross-sectional study that was conducted from November 2002 to March 2003 in the Moshi urban district of Northern Tanzania. A two-stage sampling design was used in recruiting the study participants. Information on socio-demographics, alcohol use, sexual behaviors, and STIs symptoms were obtained. Blood and urine samples were drawn for testing of HIV-1, HSV-2 and other STIs.

RESULTS

The prevalence of HSV-2 infection among all study participants was 43%. The prevalence rate of HSV-2 among the HIV-negative and HIV-positive women was 40% and 65%, respectively. We found 2.72 times odds of having HIV-1 in an HSV-2 positive woman than in an HSV-2 negative woman. Furthermore, HIV-1 and HSV-2 shared common high-risk sexual behavior factors such as early onset of sexual debut, and testing positive for other STIs.

CONCLUSIONS

Our findings suggest that HSV-2 may be both a biological and risk-associated cofactor for HIV-1 acquisition. In resource-limited countries, where both infections are prevalent efforts at symptomatic and diagnostic screening and treatment of HSV-2 should be part of HIV-1 prevention programs.

Seroprevalence, predictors and estimated incidence of maternal and neonatal Herpes Simplex Virus type 2 infection in semi-urban women in Kilifi, Kenya

Background

Herpes Simplex Virus type 2 (HSV-2) has public health importance as a leading cause of genital ulcers, a co-factor in HIV-1 acquisition and transmission and as a cause of neonatal herpes infections. Little is known of its epidemiology and burden in Coastal Kenya.

Methods

We screened plasma samples for HSV-2 infection from 826 women aged 15-34 years who participated in an HIV-1 survey in Kilifi in 2004. The sample comprised 563 women selected randomly from a demographic surveillance system (DSS) and 263 women who presented for voluntary counseling and testing (VCT). Predictors for HSV-2 seropositivity were determined using multivariate logistic regression. The incidence of HSV-2 infection and risk of neonatal herpes were estimated by a simple catalytic model fitted to age-seroprevalence data.

Results

HSV-2 prevalence was 32% in the DSS recruits vs. 44% in the VCT recruits (P < 0.001), while, HIV-1 prevalence was 8% in the DSS recruits vs. 12% in the VCT recruits (P = 0.12). Independent risk factors for HSV-2 infection in all women were: older age (30-34 years; odds ratio (OR) 10.5, 95% confidence interval (CI): 5.2 - 21.0), recruitment from VCT (OR 1.5, 95% CI: 1.1 - 2.1), history of genital ulcers (OR 1.7, 95% CI: 1.2 - 2.3) and HIV infection (OR 2.7, 95% CI: 1.6-4.6). Education beyond primary (OR 0.7, 95% CI: 0.5 - 0.9) was inversely associated with HSV-2 infection. In the DSS sample, HSV-2 incidence was estimated at 4 cases (95% CI: 3.3 - 4.4) per 100 women per year, 17 cases (95% CI: 16-18) per 1,000 pregnancies per year and 33 neonatal cases (95% CI: 31-36) per 100,000 births per year.

Conclusions

HSV-2 transmission is rapid following the onset of sexual activity and likely to result in a significant burden of genital ulcer disease. Nevertheless, the burden of neonatal HSV-2 can be predicted to be low. Educating young women about HSV-2 infection may help in reducing its burden in this semi-urban population.

Seroprevalence of herpes simplex virus type 1 and type 2 among the Indigenous population of Cape York, Far North Queensland, Australia

Background: The objective of this study was to obtain representative seroprevalence data for the Indigenous population of Far North Queensland by measuring the age- and sex-specific seroprevalence of the herpes simplex viruses (HSV-1 and HSV-2) in Cape York. Methods: A cross-sectional seroprevalence study was conducted using de-identified serum samples collected from Indigenous patients living in Cape York, aged 16 years or older, who sought medical care between August 2007 and May 2008. An age- and sex-stratified random sample of 270 sera was tested for the presence of antibodies to HSV-1 and HSV-2 using commercially available enzyme-linked immunosorbent assays. Indeterminate results were resolved with western blot. Results: The overall seroprevalence for the Indigenous population of Cape York was 97.8% for HSV-1 and 58.5% for HSV-2. There was a statistically significant difference in HSV-2 seroprevalence according to sex (P < 0.001). Females were more likely to be HSV-2 seropositive compared with males (72.1% and 43.8%, respectively). Conclusions: This is the first study to report on the seroprevalence of HSV-1 and HSV-2 among the Indigenous population of Cape York. This study has identified a population with an extremely high prevalence of HSV-1 and HSV-2 infection. The seroprevalence of HSV-2 in this population was found to be five times higher than that reported for the general adult Australian population. These results will be invaluable to the implementation of appropriate prevention and control strategies against HSV infection and are especially important considering the strong association between HSV-2 and the acquisition and transmission of HIV.

Seroprevalences of herpes simplex virus type 2 and Chlamydia trachomatis in Turkey

OBJECTIVE

Aim was to detect the seroprevalences of Herpes simplex virus type 2 (HSV-2) and Chlamydia trachomatis in a subpopulation of Turkey.

MATERIALS AND METHODS

The study was performed in the "Golbasi" rural area of Ankara, the capital city of Turkey. Ten milliliter of peripheral blood was drawn from 1,115 women over 15 years old. Once the sera were separated, ELISA was used to detect seropositivity. Data were transferred to Epi Info Version 6.0 statistical program and the analysis was performed.

RESULTS

Among all participants, 53.5% were found to be seropositive for HSV-2 and 52.2% were found to be seropositive for C. trachomatis.

CONCLUSION

This study detected a much higher HSV-2 and C. trachomatis seroprevalence for the Turkish population than expected and previously reported. A percentage around 50% for both agents creates an important conflict with the common misbelief of the Turkish population that sexually transmitted diseases are not common in this population. This study points out the importance of preventive measures and the need for greater surveillance for sexually transmitted infections among the Turkish population.

Seroprevalence of herpes simplex virus type 2 in multiple sclerosis

BACKGROUND

It has been proposed that multiple sclerosis (MS) might be a sexually transmitted disorder. There is evidence that seropositivity to herpes simplex virus type 2 (HSV-2) correlates well with the number of sexual partners. Accordingly, a raised overall HSV-2 seroprevalence in MS would lend support to this theory.

MATERIALS AND METHODS

Serum from 497 UK subjects with clinically definite MS was tested for antibodies to HSV-2 and compared with matched historical controls from within and outside London, blood donors and genito-urinary medicine (GUM) clinics.

RESULTS

The unadjusted MS seropositivity rate was 14%. HSV-2 seroprevalence in MS patients aged 35-64 years was significantly higher overall compared with a non-London general population in an unadjusted comparison. HSV-2 seroprevalence in London MS patients compared with London blood donors was significantly greater irrespective of age, but the MS seropositive rate was lower than GUM clinic attenders. In a logistic regression analysis, increased age, female sex and MS diagnosis all independently increased the odds of seropositivity after adjustment for each other.

CONCLUSION

It is concluded that there is increased likelihood of HSV-2 exposure in patients with MS and this may indicate a higher than average number of partners.

Prevalence of infection with herpes simplex virus types 1 and 2 in Australia: a nationwide population based survey

BACKGROUND

Studies demonstrating previous herpes simplex virus (HSV) type 2 infection as a risk factor for HIV transmission, and the development of a HSV vaccine candidate, have emphasised the need for worldwide population based studies of HSV seroprevalence. The only nationwide seroprevalence studies have been conducted in the United States.

METHODS

An Australia-wide, population based study of HSV-1 and HSV-2 seroprevalence was conducted, using serum and sociodemographic data collected between 1999-2000, for a representative study of risk factors for diabetes in over 11 000 adults. A stratified random sample of 4000 was tested for HSV-2 and 1000 for HSV-1, with sampling and weighting for various demographic factors.

RESULTS

Seroprevalence of HSV-2 in Australian adults was 12%. Prevalence in women (16%) was twice that in men (8%). Rural populations had a lower prevalence (9%) than metropolitan (13%), and Indigenous had a higher prevalence (18%) than the non-Indigenous populations (12%). The seroprevalence of HSV-1 was 76% with significant differences by age group, sex and Indigenous status.

CONCLUSION

These are the first nationwide data to compare with US studies. HSV-2 infection is less common in Australia than the United States, and this will allow planning for combating HIV transmission in high prevalence populations in northern Australia. In addition, the high HSV-1 seroprevalence will be important for future deployment of genital herpes vaccines.

Genital herpes in adolescents

Herpes simplex virus (HSV) infections occur commonly among adolescents. Most HSV-2 infections are genital, but genital herpes can be caused by either HSV-1 or HSV-2. Weighted means were calculated based on published seroprevalence data on adolescents from the United States and found HSV-1 rates of 53.1 percent for adolescent males and 49.4 percent for adolescent females. The weighted means for HSV-2 was 15 percent for adolescent females and 12 percent for adolescent males. Most individuals who are infected with HSV-2 are unaware of their infection. Healthcare providers of adolescents should consider genital herpes even when an adolescent presents with nonspecific genital symptoms. In this article, we review current recommendations for diagnosis and management and review the psychological sequelae that can be associated with having genital herpes. Finally, we discuss biomedical interventions that are being developed to help reduce the epidemic of HSV and the challenges that these interventions face with regard to implementation.

The seroepidemiology of herpes simplex virus type 1 and 2 in Europe

OBJECTIVES

To describe the seroepidemiology of herpes simplex virus (HSV) types 1 and 2 in the general populations of eight European countries to better understand recent reported changes in disease epidemiology.

METHODS

Belgium, Bulgaria, Czech Republic, England and Wales, Finland, Germany, Netherlands, and Slovenia conducted national cross sectional serological surveys for HSV-1 and HSV-2 between 1989 and 2000. Survey sizes ranged from 3000 to 7166 sera. External quality control was ensured through reference panel testing.

RESULTS

Large intercountry and intracountry differences in HSV-1 and HSV-2 seroprevalence were observed. Age standardised HSV-1 seroprevalence ranged from 52% in Finland, to 57% in the Netherlands, 67% in Belgium, 81% in Czech Republic, and 84% in Bulgaria. Age standardised (>12 years) HSV-2 seroprevalence ranged from 24% in Bulgaria, to 14% in Germany, 13% in Finland, 11% in Belgium, 9% in Netherlands, 6% in Czech Republic, and 4% in England and Wales. In all countries, probability of seropositivity for both infections increased with age. A large proportion of teenagers and young adults remain HSV-1 susceptible particularly in northern Europe. Women were significantly more likely to be HSV-2 seropositive in six of seven (p<0.05) countries and HSV-1 seropositive in four of seven (p<0.05) countries, particularly in northern Europe. No significant evidence of a protective role of HSV-1 for HSV-2 infection was found adjusting for age and sex (p<0.05).

CONCLUSIONS

There is large variation in the seroepidemiology of HSV-1 and HSV-2 across Europe. The observation that a significant proportion of adolescents are now HSV-1 susceptible may have implications for transmission and clinical presentation of HSV-1 and HSV-2.

New estimates of herpes simplex virus type 2 seroprevalence in England: 'high' but stable seroprevalence over the last decade

OBJECTIVES

There have been few recent population-based herpes simplex virus type 2 (HSV-2) seroprevalence studies in England, but reports from the United States have indicated a 30% rise in HSV-2 seroprevalence between 1976 and 1994. This study aimed to ascertain trends in HSV-2 infection in England between 1991 and 2000.

STUDY DESIGN

Anonymized serum residues collected through public health laboratories across England from individuals aged 16 to 64 years seeking health care through the National Health Service in 1991 (n = 2259) and 2000 (n = 3646) were tested for anti-HSV-2 IgG using the HerpeSelect 2 enzyme-linked immunosorbent assay IgG (Focus).

RESULTS

In 9 sites across England, the age- and sex-standardized HSV-2 seroprevalence was 9.7% (95% confidence interval, 8.4-11.0%). Data from 4 sites common to both study years indicated no change in HSV-2 seroprevalence between 1991 and 2000.

CONCLUSIONS

After adjustment for age, sex, and geographic location, there was no evidence of a change in seroprevalence between 1991 and 2000.

Seroprevalences of herpes simplex virus type 1 and type 2 among pregnant women in the Netherlands

BACKGROUND

In the Netherlands 73% of cases of neonatal herpes are caused by herpes simplex virus type 1 (HSV-1), whereas in the United States a majority are caused by HSV type 2 (HSV-2). GOAL To understand this difference we undertook a seroepidemiological study on the prevalence of HSV-1 and HSV-2 among pregnant women.

STUDY DESIGN

Type-specific antibodies to HSV-1 and HSV-2 were detected by enzyme-linked immunosorbent assay (ELISA) in serum samples from 1,507 pregnant women in Amsterdam, Rotterdam, and Nijmegen.

RESULTS

The prevalence of HSV-1 was 61% in Nijmegen, 73% in Amsterdam, and 75% in Rotterdam. The prevalence of HSV-2 was 11% in Nijmegen, 35% in Amsterdam, and 27% in Rotterdam.

CONCLUSION

The seroprevalence of HSV-1 and HSV-2 antibodies among pregnant women in the Netherlands shows significant geographical differences, which were attributed to ethnical variation. However, the epidemiologic differences did not correlate with the incidence of neonatal herpes in the Netherlands.

Prevalence of herpes simplex virus type 2 antibody in Cameroon

BACKGROUND

Genital herpes is one of the most common sexually transmitted diseases. As a leading cause of genital ulceration, herpes genitalis plays a role in facilitating the transmission of HIV. Although HIV infection is most prevalent in Cameroon, information is lacking about prevalence of herpes simplex virus (HSV) type 2 infection in this country.

GOAL

The goal was to determine the prevalence of HSV-2-specific antibody in blood specimens from individuals in Cameroon.

STUDY DESIGN

Blood specimens were randomly collected from 410 clinic attendees (215 males, 195 females) in Douala, the most populous city in Cameroon. One hundred fifteen of the individuals (28.0%) were HIV-infected. Samples were tested by a type-common HSV IgG enzyme immunoassay not discriminating between HSV-1 and HSV-2 antibodies and by two glycoprotein G-2-based enzyme immunoassays for detection of HSV-2-specific antibody.

RESULTS

All but three blood samples were positive for type-common HSV IgG antibodies. Sixty-seven specimens (16.3%) were concordantly negative for HSV-2 antibody by both assays, and 287 (70.0%) specimens were concordantly positive. Fifty-six specimens (13.7%) yielded discrepant results between the two assays.

CONCLUSION

On the basis of specimens with concordantly positive results, the overall HSV-2 seroprevalence was 70.0%. HSV-2 seroprevalence was significantly higher among HIV-infected individuals than among HIV-negative ones. Because of the serious morbidity and mortality caused by HSV-2, effective programs are needed to halt the spread of HSV-2 infection in Cameroon.

Age-specific prevalence of infection with herpes simplex virus types 2 and 1: a global review

Information on age- and sex-specific prevalence of herpes simplex virus (HSV) types 2 and 1 infections is essential to optimize genital herpes control strategies, which increase in importance because accumulating data indicate that HSV-2 infection may increase acquisition and transmission of human immunodeficiency virus. This review summarizes data from peer-reviewed publications of type-specific HSV seroepidemiologic surveys. HSV-2 prevalence is, in general, highest in Africa and the Americas, lower in western and southern Europe than in northern Europe and North America, and lowest in Asia. HSV-2 and -1 prevalence, overall and by age, varies markedly by country, region within country, and population subgroup. Age-specific HSV-2 prevalence is usually higher in women than men and in populations with higher risk sexual behavior. HSV-2 prevalence has increased in the United States but national data from other countries are unavailable. HSV-1 infection is acquired during childhood and adolescence and is markedly more widespread than HSV-2 infection. Further studies are needed in many geographic areas.

Herpes simplex virus type-2 infection in pregnancy: no risk of fetal death: results from a nested case-control study within 35,940 women

OBJECTIVE

The aim of this study was to assess the association of fetal death with herpes simplex virus type-2 (HSV-2) antibody status during pregnancy: 1. presence of antibodies in first trimester; 2. appearance of antibodies (incident infection); 3. increase in antibody titre; and 4. loss of antibodies.

DESIGN

Prospective study.

POPULATION

The source population was a cohort of 35,940 pregnant women in Norway.

METHODS

Nested case-control study within the cohort. Cases were all women in the study population who experienced a fetal death after the 16th weeks of gestation (n = 281), and controls were 961 randomly selected women with a live born child.

MAIN OUTCOME MEASURES

HSV-2 antibody status.

RESULTS

Twenty-nine percent (82/281) of women with a fetal death and 27% (256/961) of the controls had of HSV-2 antibodies present in the first trimester (odds ratio 1.1, 95% CI 0.8-1.5). HSV-2 antibodies appeared in 2% (3/136) of initially seronegative cases and 3% (16/623) of the controls during pregnancy (odds ratio 0.9, 95% CI 0.2-3.0). An increase in HSV-2 antibodies occurred in 4% (2/55) of initially seropositive cases and 7% (16/231) of the controls (odds ratio 0.5, 95% CI 0.1-2.3). Loss of HSV-2 antibodies in initially seropositive women was not associated with fetal death, 42% (23/55) of the cases and 45% (104/231) of the controls seroreverted (odds ratio 0.8, 95% CI 0.5-1.6). Differences in follow up time, age and parity were controlled and did not influence the comparisons between cases and controls.

CONCLUSION

This study provides no evidence of an association between HSV-2 infection during pregnancy and fetal death.

HIV infection among youth in a South African mining town is associated with herpes simplex virus-2 seropositivity and sexual behaviour

OBJECTIVES

To determine the seroprevalence of HIV and herpes simplex virus-2 (HSV-2) by age and gender among young people aged 14--24 years in a South African town and to identify risk factors for HIV infection.

DESIGN

A community-based, cross-sectional study was conducted on a random sample of men (n = 723) and women (n = 784) living in a township in the Carletonville district of South Africa.

METHODS

Potential demographic and behavioural risk factors associated with HIV were recorded by questionnaire and biological tests were performed on serum and urine. Data analysis was performed using multivariate logistic regression.

RESULTS

Among men and women the prevalence of HIV infection was 9.4 and 34.4%, respectively, and of positive HSV-2 serology was 17.0 and 53.3%, respectively. Among 24-year-old women the prevalence of HIV was 66.7% [95% confidence interval (CI), 54.6--77.3%]. HSV-2 seropositivity was a strong independent risk factor for HIV infection with odds ratios of 5.3 (95% CI, 2.7--10.3) for men and 8.4 (95% CI, 4.9--14.2) for women. There was no independent effect of age at first sex or serological markers of other sexually transmitted infections on HIV infection.

CONCLUSIONS

HIV infection among young women increases rapidly after the onset of sexual activity and reaches extremely high levels by 24 years of age. These findings suggest that rates of HIV transmission from men to women are high and that HSV-2 plays a major role in the spread of HIV in this population.

Genital herpes in pregnancy: is screening cost-effective?

We investigated the cost-effectiveness of strategies for screening pregnant women for herpes simplex virus (HSV) genital infection. The cost of performing tests for HSV-1 antibody and for HSV-2 antibody on each serum was likely to average approximately £10 per sample and the total cost of screening 37,500 pregnancies in Manchester would be between £0.4 and £0.5 million per year. This estimated cost might prevent the development of neonatal herpes due to a primary HSV infection. However, initial HSV-2 infection is also associated with neonatal herpes and therefore the above cost-estimates might be a gross underestimate.

Herpes simplex virus type 2 seroepidemiology in Spain: prevalence and seroconversion rate among sexually transmitted disease clinic attendees

BACKGROUND

Only limited data on the seroprevalence of herpes simplex virus type 2 (HSV-2) are available from European countries. Until recently, serologic tests for HSV-2 serotyping have been hampered by cross-reactivity to type-common antigens. The present study aims at providing data on the prevalence of HSV-2 infection in a group of STD clinic attendees using a reliable type-specific immunoassay.

GOAL

To evaluate the seroprevalence of HSV-2 and the accumulated incidence of clinical genital herpes infection in a sample of Spanish sexually transmitted disease (STD) clinic attendees.

STUDY DESIGN

The study consisted of two parts. First, a cross-sectional study of HSV-2 seroprevalence was conducted in patients with STDs. Second, a prospective cohort study was undertaken to evaluate the accumulated incidence of infection by HSV-2 and of clinical episodes of genital herpes in HSV-2-negative patients included in the first study during a follow-up period of 6 to 18 months.

RESULTS

Of the 374 patients (129 men, 245 women) studied, 25% were seropositive for HSV-2 (12% of men, 30% of women). Antibodies to HSV-2 were related to female gender (odds ratio, 2.7; P < 0.001) and to the number of sexual partners (odds ratio, 4.1; P < 0.001). Fifty-two percent of patients (145 of 281 patients) who were initially seronegative returned to the clinic for a second serologic testing, of whom 1% (2 of 145 patients) had seroconverted. None of the patients developed genital herpes during the follow-up period.

CONCLUSION

The relatively high seroprevalence (25%) and the low rate (4%) of HSV-2 previously reported in the general population in Spain suggest that the virus circulation may be restricted to certain risk groups. Therefore, future healthcare measures may target specific groups, such as patients with STDs.

Neonatal herpes prevention: a minor public health problem in some communities

BACKGROUND

Neonatal herpes is a condition with high morbidity and mortality. The greatest risk occurs when the mother acquires herpes simplex virus (HSV) towards the end of pregnancy. A study from Seattle has suggested that the risk of acquisition of HSV during pregnancy was 3.7%. In Australia, HSV-2 infection is less common in pregnant women than in the United States. Consequently we conducted a study to establish HSV seroprevalence and the rate of HSV seroconversion in this population.

METHODS

The study was conducted at Westmead Hospital, Sydney, between June 1995 and April 1998. Women completed a questionnaire covering risk factors for the acquisition of genital herpes. A serum sample during pregnancy and a specimen of cord blood were obtained and tested for antibodies to HSV-2 using a type specific indirect enzyme linked immunosorbent assay (ELISA). Equivocal results were resolved by western blot. A subset of the paired sera was tested for antibodies to HSV-1. The data were analysed using SPSS.

RESULTS

326 of the 2616 (12.5%) women were HSV-2 seropositive. Three women (0.15%) acquired HSV-2 infection during pregnancy. None of the three babies of these mothers developed neonatal herpes. 416 maternal cord pairs were tested for HSV-1 antibodies and 330 (79.3%) were positive. No HSV-1 seroconversions occurred.

CONCLUSIONS

In this population, HSV acquisition was uncommon (0.34% per year) and neonatal herpes was rare. A cost effective analysis suggested that type specific serology to screen pregnant women and their partners in low prevalence communities was not cost effective.

The burden of infection with HSV-1 and HSV-2 in England and Wales: implications for the changing epidemiology of genital herpes

OBJECTIVE

To measure the burden of infection with herpes simplex type 1 (HSV-1) and herpes simplex type 2 (HSV-2) in the general population of England and Wales and to assess temporal changes in the incidence of HSV-1 infection in childhood.

METHODS

4930 residual blood samples taken from people aged 0-69 years and submitted to 15 public health laboratories in England and Wales between January 1994 and June 1995, and 500 samples taken from people aged 10-14 years between November 1986 and December 1987, were screened for IgG antibody to HSV-1 and HSV-2 using type specific ELISA assays.

RESULTS

The prevalence of antibody to HSV-1 in 10-14 year olds declined from 34% in samples collected in 1986-7 to 24% in samples collected in 1994-5 (p < 0.001). HSV-1 antibody prevalence in adults increased with age and was higher in females than males, reaching 54% in females aged 25-30 years in 1994-5. In samples collected in 1994-5 from people aged 16-69 years HSV-2 antibody was detected in sera from 3.3% of men and 5.1% of women.

CONCLUSIONS

The incidence of HSV-1 infection in childhood is falling in England and Wales. The prevalence of HSV-2 infection in the general population is low, with the rate of infection significantly lower than that described for the general population in the United States and developing countries. The falling rate of HSV-1 infection in childhood may be one factor contributing to the increasing incidence of genital HSV-1 infection.

Seroprevalence of herpes simplex virus type 2 infection among attendees of a sexually transmitted disease clinic in Italy. Italian Herpes Forum

BACKGROUND AND OBJECTIVES

An increased prevalence of herpes simplex virus type 2 (HSV-2) infection has been recently observed in industrialized countries.

GOAL

To determine HSV-2 seroprevalence in a high-risk population in Italy.

STUDY DESIGN

A cross-sectional study was performed to ascertain the HSV-2 prevalence among 919 persons attending an STD clinic in northern Italy. A HSV-2-specific glycoprotein G-2-based immunoglobulin G enzyme-linked immunoabsorbent assay (Gull/Meridian ELISA; Meridian Diagnostics, Cincinnati, OH) was used and validated against Western blot analysis.

RESULTS

A prevalence of 24.6% was found without differences between males and females. Seroprevalence increased with age and number of partners during the previous year. Compared with Western blot analysis, the Gull/Meridian ELISA showed a sensitivity of 91.9% and a specificity of 98%, and positive and negative predictive values of 93.9% and 97.4%, respectively.

CONCLUSION

This is the first Italian survey of HSV-2 infection conducted with a properly validated, Food and Drug Administration-approved, type-specific serologic method in a high-risk population. It is likely that between one to three million adults are infected with HSV-2.

HSV-2 specific serology should not be offered routinely to antenatal patients

The proposal to introduce antenatal screening for HSV has no evidence for a public or individual health benefit; indeed, it has the potential to increase anxiety for patients, with a minimal likelihood of reducing the risk of neonatal herpes infection. Antenatal screening of an essentially healthy population of women must be validated in settings of different rates of neonatal HSV infection and the purposes and limitations of screening clearly outlined. Identification of pregnant women at risk of acquiring genital herpes in pregnancy is also dependent upon being able to obtain the serostatus of the male sexual partner which will reduce the practical application of the test if both patient and partners need to be screened. We recommend that efforts to improve on the currently established mechanisms for reducing the morbidity of neonatal herpes, namely early diagnosis and prompt treatment, must take priority for resources over new and unevaluated screening programmes, such as routine testing of antenatal patients.

Whole cell lysate enzyme immunoassays vs. recombinant glycoprotein G2-based immunoassays for HSV-2 seroprevalence studies

Seroepidemiology studies of herpes simplex virus type 2 (HSV-2) infections have been difficult to carry out because antibodies to HSV type 1 (HSV-1) show an extensive cross-reactivity with HSV-2 antigens. Many kits available currently are not entirely type specific for serodiagnosis of HSV-2 infections and therefore do not allow reliable discrimination of past exposure to these closely related alphaherpes viruses. Attempts to develop type-specific antigens have focused on the envelope glycoproteins, particularly glycoprotein G (gG). A cross-sectional study was carried out to examine the seroprevalence of antibodies to HSV-2 among healthy university students, using different methods: a whole cell lysate enzyme-linked immunosorbent assay (ELISA), two different ELISAs, and a newly developed immunoblot assay, the last three based on recombinant gG2. HSV-2 prevalence was 24 times higher with the whole cell lysate ELISA (31%; 95% confidence interval [CI]: 27-35%) than the ELISAs and the immunoblot assay based on recombinant gG2 (1.3%; 95% CI: 0.1-2.5%), thus showing the inaccuracy of commercial tests based on whole-antigen preparations for epidemiological studies. Laboratories should be cautious and ensure that commercial tests for HSV typing are based on type-specific glycoproteins.

Is sexual transmission an important pattern for herpes simplex type 2 virus seroconversion in the Spanish general population?

Herpes simplex type 2 (HSV-2) seroprevalence within a community is determined by sexual and perinatal transmission from mother to baby, the two main sources of virus shedding. A seroepidemiological study of HSV-2 was undertaken on a representative sample (n = 3974) of the Spanish population to assess indirectly the relative relevance of these two transmission routes. The sample comprised 1922 men and 2052 women in the age range 5-59 years, stratified by sex and age (5-12, 13-19, 20-29, 30-39, 40-49, and 50-59 years). Sera were screened for HSV-2 specific Ig G antibodies by an enzyme-linked immunoabsorbent assay based on recombinant glycoprotein G2 (gG2). The overall prevalence of antibodies to HSV-2 was 3.6% (95% CI: 3. 1-4.2%). Prevalence by gender did not differ: males (3.6%; 95% CI: 2. 8-4.6%) and females (3.6%; 95% CI: 2.8-4.5%). There were no significant differences between age groups with respect to seropositivity rates. Detection of HSV-2 antibodies was not associated with increasing age, as is expected for a sexually transmitted disease. The fact that seroprevalence rates among the different age groups did not differ suggests that the virus is not circulating in the general population and may be restricted to risk groups only. Similar positivity rates found in the group of females of childbearing age and in the youngest population indicate that perinatal viral shedding is the main source of HSV-2 seroconversion in the Spanish population.

The international development of the RGHQoL: a quality of life measure for recurrent genital herpes

This paper describes the international development and psychometric testing of the Recurrent Genital Herpes Quality of Life Questionnaire (RGHQoL), a condition-specific quality of life (QoL) instrument. The theoretical foundation for the measure is the needs-based model of QoL and the content of the instrument was derived from in-depth qualitative interviews with relevant patients in the UK. Versions of the RGHQoL were required for the UK, USA, Italy, Germany, France and Denmark for use in international clinical trials. The results indicate that the final 20 item measure has good reliability, internal consistency and validity for all language versions. A small responsiveness study in Denmark suggested that the measure is sensitive to changes in QoL associated with the initiation of suppression treatment for recurrent genital herpes (RGH). It is concluded that the RGHQoL is a valuable instrument for inclusion in clinical trials. The psychometric properties of the instrument are such that it may also be used to monitor the progress of individual patients.

HSV-1 and HSV-2 in herpes simplex encephalitis: a study of sixty-four cases in the United Kingdom

The incidence of herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2) in herpes simplex encephalitis (HSE) was investigated using cerebrospinal fluid (CSF) samples from sixty-four cases of HSE. A polymerase chain reaction (PCR) employing primers flanking a region of the HSV thymidine kinase gene common to both HSV-1 and HSV-2 was used to detect HSV in the CSF. HSV-1 and HSV-2 were differentiated by digestion with restriction enzymes. Two enzymes were employed; Aval which cleaved only the HSV-2 gene product and Avall which cleaved only the HSV-1 gene product. Sixty-three cases of HSE were found to be due to HSV-1; one case due to HSV-2. These data confirm previous observations that HSV-2 is a rare cause of post-neonatal herpes encephalitis but indicates that a PCR procedure capable of detection of both viruses is essential for efficient diagnosis of HSE.

Prevalence of Kaposi's sarcoma associated herpesvirus infection measured by antibodies to recombinant capsid protein and latent immunofluorescence antigen

BACKGROUND

Kaposi's sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8, may be the infectious cause of KS. Its prevalence in the general population, on the basis of detection of the virus genome, is controversial. To investigate the seroprevalence, we measured antibodies to a recombinant capsid-related (lytic cycle) KSHV antigen and a latent antigen complex.

METHODS

We selected potentially immunoreactive capsid-related proteins of KSHV by expressing them as recombinant proteins and testing them in western blot assays. We used a truncated recombinant protein encoded by KSHV open reading frame 65 (orf 65) to develop a diagnostic enzyme-linked immunosorbent assay (ELISA) and tested sera from HIV-infected individuals with KS, HIV-uninfected patients with "classic" KS, other HIV risk groups, and blood donors. We also compared the antibody response to this capsid-related protein to the response to latent antigen(s) in an immunofluorescence assay.

FINDINGS

77/92 (84%) sera from KS patients reacted with the KSHV orf 65 protein and 84/103 (81.5%) reacted with KSHV latent antigen(s). The dominant immunogenic region of orf 65 is within the carboxyterminal 80 aminoacids, a region with little sequence similarity to the related Epstein-Barr virus, suggesting that orf 65 is a KSHV specific antigen. Only three sera from patients with haemophilia (1/84) or from intravenous drug users (2/63) had KSHV specific antibodies in the orf 65 assay whereas none of these sera reacted with latent antigen. Antibodies to KSHV were also infrequently found in UK and US blood donors by either assay (UK, 3/174 with orf 65 and 4/150 with latent antigen; US, 6/117 with orf 65 and 0/117 with latent antigen). They were more common among HIV-infected gay men without KS (5/16 by orf 65 ELISA, 10/33 by IFA), HIV-uninfected STD clinic attenders (14/166 by IFA), and Ugandan HIV-uninfected controls (6/17 by orf 65 ELISA, 9/17 by IFA). Antibody reactivity to the orf 65 protein (ELISA) and to latent antigen(s) (IFA) was concordant in 89% of 462 sera tested but reactive blood donor sera were discordant in both assays. Four AIDS-KS sera were unreactive in both assays.

INTERPRETATION

The distribution of antibodies to both a capsid-related recombinant protein and latent antigen(s) of KSHV strongly supports the view that infection with this virus is largely confined to individuals with, or at increased risk for, KS. However, infection with KSHV does occur, rarely, in the general UK and US population and is more common in Uganda. Antibodies to latent antigen(s) or to orf 65 encoded capsid protein will not detect all cases of KSHV infection, and a combination of several antigens will probably be required for accurate screening and confirmatory assays.

The role of laboratory investigation in the diagnosis and management of patients with suspected herpes simplex encephalitis: a consensus report. The EU Concerted Action on Virus Meningitis and Encephalitis

As effective therapies for the treatment of herpes simplex encephalitis (HSE) have become available, the virology laboratory has acquired a role of primary importance in the early diagnosis and clinical management of this condition. Several studies have shown that the polymerase chain reaction (PCR) of CSF for the detection of herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2) DNA provides a reliable method for determining an aetiological diagnosis of HSE. The use of PCR in combination with the detection of a specific intrathecal antibody response to HSV currently represents the most reliable strategy for the diagnosis and monitoring of the treatment of adult patients with HSE. The use of these techniques has also led to the identification of atypical presentations of HSV infections of the nervous system and permits the investigation of patients who develop a relapse of encephalitic illness after an initial episode of HSE. A strategy for the optimal use of the investigative laboratory in the diagnosis of HSE and subsequent management decisions is described.

Neonatal herpes simplex virus infection in the British Isles

This study was set up to estimate the incidence of neonatal herpes simplex virus (HSV) infection in the British Isles, and to document the outcome of neonatal infection. Paediatricians reported cases of neonatal HSV through the active reporting scheme of the British Paediatric Association Surveillance Unit. Over a 5 1/2 year period (1986-91) 76 infants with neonatal HSV infection were reported, an incidence of recognised infection in the British Isles of 1.65/100000 livebirths. Twenty-five infants had HSV-1 infection, 24 HSV-2 and in 27 virus type was unknown. Twenty-seven had disseminated infection, 23 herpes encephalitis and 26 localised infection. Nineteen infants (25%) died in the neonatal period, and a further 25 (33%) have subsequently died or have long-term sequelae. At least half of the infants had been discharged home before symptoms became apparent. For 21 women there was evidence of a maternal genital herpes infection at some time, but this was reported or diagnosed retrospectively after neonatal HSV was suspected in 19 cases, and antenatally in only two. Neonatal HSV is rare in the British Isles and routine antenatal screening for genital herpes infection during pregnancy is not justified. A high proportion of infected infants present with non-specific signs and symptoms and without mucocutaneous involvement; furthermore, there is rarely a history of maternal infection. As early diagnosis and prompt treatment is essential, there must be a high level of awareness of the serious nature of neonatal HSV infection.

Lymphocyte responses to human cytomegalovirus in different groups of patients in Britain and in adults from west Africa and the Middle East

Antibody prevalence and lymphocyte proliferation responses to cytomegalovirus (CMV) and herpes simplex virus (HSV) were compared in several different groups of patients: genitourinary medical (GUM) patients, hemophiliacs, men with clinical acquired immunodeficiency syndrome (AIDS) and cases of primary CMV mononucleosis, and also in adults in the general population (control subjects) comprising separate groups native to Britain, West Africa, and the Middle East. Among the British control subjects who were positive for CMV IgG, all were also positive against CMV antigen by the lymphocyte transformation test (LTT). However, among those who were CMV IgG-positive in the various groups of patients, 20-86.9% gave positive responses to CMV antigen by the LTT; moreover, 75.7% and 55.5% of the CMV IgG-positive healthy control subjects from West Africa and the Middle East, respectively, gave positive LTT responses to CMV antigen. When the same groups of patients were tested for responsiveness to HSV antigen by the LTT, there was good agreement between a positive result by this test and by serology in all except those with primary CMV mononucleosis (42.8%). Overall, lymphocyte responses to CMV were significantly impaired in healthy, CMV antibody-positive subjects from West Africa and the Middle East compared to similar subjects from Britain.

A comparison of referral patterns and characteristics of patients with first episode symptomatic genital HSV-1 and HSV-2 infections in Sheffield

OBJECTIVE

To ascertain factors associated with HSV-1 and HSV-2 isolates in patients attending a genitourinary medicine clinic with symptomatic first episode genital herpes (FEGH).

DESIGN

Retrospective study.

SUBJECTS

A total of 606 females and 333 males presenting with culture positive FEGH between 1990-94.

SETTING

Department of Genitourinary Medicine, Royal Hallamshire Hospital, Sheffield, UK.

METHODS

Group comparison of referral patterns, demographic data, prior and concurrent episodes of STD, recent partner change.

RESULTS

HSV-1 infected patients of either sex were more likely to be general practitioner (GP) referred, to be white, and less likely to have had preceding STD episodes. Recent sexual partner change had occurred significantly more often in HSV-2 infected females but there was no similar difference between HSV-1 and HSV-2 infected males.

CONCLUSION

The relative HSV-1:HSV-2 isolate ratio in FEGH is influenced by the referral patterns. HSV-1 isolates predominate in patients presenting to GPs who refer the patients to GUM clinics for accurate diagnosis, counselling, follow up and screening for other STDs.

Viral infections in the immunocompetent patient

Human herpesviruses and human papillomaviruses are ubiquitous and may cause an array of oral disease. Herpesviruses are unique because recurrent localized disease occurs after the primary infection. Human papillomaviruses are known for their ability to produce benign epithelial proliferations and increasingly are implicated in the development of oral cancer. This article reviews the pathogenesis of common oral lesions induced by these viruses.

Seroprevalence and incidence of sexually transmitted diseases in a rural Ugandan population

The aim of the study was to determine in a rural population the age- and sex-specific prevalence and incidence rates of serological reactivity of 5 common sexually transmitted diseases (STDs) and their association with HIV-1 antibody status. Of the adult population of two villages (529 adults aged 15 years or more) 294 provided an adequate blood specimen both on enrollment and at 12 months. The sera were tested at 3 collaborating laboratories for antibodies against HIV-1, Treponema pallidum, Haemophilus ducreyi, Chlamydia trachomatis and herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2). A sample of 45 children were tested for HSV-1 and HSV-2. Seroprevalence rates in adults on enrollment were 7.8% for HIV-1, 10.8% for active syphilis, 10.4% for H. ducreyi, 66.0% for C. trachomatis, 91.2% for HSV-1 and 67.9% for HSV-2. Males were significantly more likely than females to be seropositive for H. ducreyi (15.6% versus 6.6%), but less likely to be HSV-2 antibody positive (57.0% versus 74.4%). Reactivity to H. ducreyi, C. trachomatis and HSV-2 rose with increasing age. In contrast, active syphilis showed no age trend. All STDs tended to be more common in those HIV-1 seropositive. Incidence rates over the 12 months were nil for HIV-1, 0.5% for syphilis, 1.2% for H. ducreyi, 11.3% for C. trachomatis, and 16.7% for HSV-2. The results of this exploratory study indicate that all STDs included are common in this rural population. The high HSV-2 prevalence rate among adolescents suggests that HSV-2 may be an important risk factor for HIV-1 infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence of antibodies to herpes simplex virus in pregnant women in Stockholm in 1969, 1983 and 1989: implications for STD epidemiology

Prevalence of antibody to herpes simplex virus types 1 and 2 was assessed in consecutive serum samples from a total of 3700 women pregnant in 1969, 1983, or 1989 from the same catchment area in Stockholm. There was little change in seroprevalence of antibody to herpes simplex type 1 in the 3 groups, but age-adjusted herpes simplex virus type 2 antibody prevalence was 19, 33, and 33% respectively. Increase in type 2 seropositivity with age was slight and similar in 1969 and 1989, but steep in 1983, indicating a shift in sexual behaviour. However, rising prevalence in women will be mirrored by rising prevalence in their male partners. The increase from 1969 to 1989 will thus partly be due to higher risk of infection per partner, and cannot be taken as direct evidence of increased rate of partner change during this 20-year period.

A comparison of sexual behaviour and risk behaviour for HIV infection between women in three clinical settings

OBJECTIVE

To compare sexual behaviour and HIV risk behaviour between women in three clinical settings and to investigate the effect of socio-economic status and ethnic origin upon these behaviours.

SUBJECTS AND METHODS

A questionnaire was administered to 1,950 women attending clinics for genitourinary medicine (GUM) family planning and termination of pregnancy (TOP), all in inner London.

RESULTS

A quarter of women attending the GUM and TOP clinics were not using any regular form of contraception. Differences in the median numbers of sexual partners in the past year (1-2) and over lifetime (4-6) between the three groups were slight. Amongst the women in all three groups: more than half (54.8-64.9%) had had a non-regular partner in the preceding twelve months; fewer than one-fifth (10.4-17.1%) reported always using condoms with their regular partners, and fewer than two-fifths (31.3-39.7%) always used them with their non-regular partners; approximately one in five women (18.6-23.9%) reported one or more major HIV risk behaviours. Some parameters of sexual behaviour were found to be influenced by socio-economic status and/or ethnic origin.

CONCLUSIONS

The behaviour of women attending these three clinics is very similar. Women attending clinics for family planning or termination of pregnancy need advice on sexually transmitted diseases and HIV infection, and women attending genitourinary medicine or termination clinics need advice on contraception. Closer integration between disciplines is required to provide a comprehensive sexual health service for women.

AIDS: trends, predictions, controversy

One of the persistent controversies that surfaces in the media about AIDS is whether the heterosexual population is at risk. The latest projections provide an emphatic affirmative.

Modified latex agglutination test for antibodies to Toxoplasma gondii in eluates from Guthrie cards

AIMS

To determine whether the Eiken particle agglutination test could be modified to make it sufficiently sensitive to screen blood samples collected on Guthrie cards for the presence of antibodies to Toxoplasma gondii; to evaluate the specificity of the modified system; and to compare seroepidemiological data on the prevalence of T gondii in pregnant women.

METHODS

Simulated dried blood spots were prepared from sera from pregnant women booking for antenatal care. Eluates from the simulated dried blood spot cards and sera were tested in parallel using the modified test (1 in 5 dilution of latex) and the standard assay (neat latex particles) and endpoints determined. Guthrie card eluates, from neonates in three Thames regions, were then tested using the modified test.

RESULTS

The modified test produced a 4.21-fold increase in antibody titre in 85 sera when tested in parallel with the standard test. Eluates of 168/170 from simulated dried blood spots derived from seropositive patients gave a positive result in the modified test. The two eluates which gave a negative result were derived from patients with an equivocal titre of 1/16 in the standard serum test. Of the eluates derived from serum negative patients all 103 were negative at a dilution of 1 in 4 in the modified test. The seroprevalence of antibodies to T gondii in pregnancy was 21.8% using the standard test. A similar value of 20.5% was obtained when dried blood spots from neonates in a similar region of London were tested by the modified test.

CONCLUSIONS

The modified Eiken Toxo-reagent test is sensitive, simple, and economic for screening large numbers of dried blood spots. The procedure could be easily semiautomated and the technique applied to the mass screening of neonatal blood samples collected on Guthrie cards to determine the seroprevalence of T gondii in pregnant women.

A 15-year surveillance study of antibodies to herpes simplex virus types 1 and 2 in a cohort of young girls

A cohort of 839 young girls at the ages of 14 and 15 years was screened for total antibodies to herpes simplex virus (HSV) and, if positive, for specific antibodies to HSV-2, by means of a sensitive, enzyme-linked immunosorbent assay (ELISA). The cohort was followed from 1972-1987. Blood samples were obtained on six occasions during these 16 years. In total, 2270 blood samples were taken. The number of sero-converting girls was studied in relation to calendar time. Two methods were constructed for the statistical analyses. The first of these gave an estimate of the sero-prevalence at different points in time. This analysis showed that the sero-prevalence which was 23% against HSV-1 in 1972 had increased to 36% in 1976. At the end of the study in 1987, 50% of the cohort had sero-converted against HSV-1. The proportion of girls who had sero-converted against HSV-2 was 0.4% in the 14-15-year-olds and had reached 22% by the end of the study. The second statistical method used all the available information implicit in the observations so as to obtain a maximum-likelihood (ML) estimate of the prevalence. The ML estimates were slightly more precise, but the two estimates did not differ significantly. The observations were further analysed by the Mantel-Haenszel test in order to see if there was any dependence between positivity to HSV-1 and HSV-2 respectively but none was found.

Evaluation of five commercial assays for screening antenatal sera for antibodies to Toxoplasma gondii

AIMS

To evaluate the suitability of five commercial assays (Toxoreagent, DA, Captia Toxo IgG, Toxenz-G, Toxonostika-G) for screening large numbers of sera for antibodies to Toxoplasma gondii.

METHODS

Sera from 1000 pregnant women booking for antenatal care at a London hospital were screened in parallel by each test. Sera giving discordant results were retested.

RESULTS

The Captia Toxo IgG enzyme immune assay gave the best specificity on initial screening, with 0/773 false positives and only 2/218 false negatives. The Toxoreagent latex agglutination test performed well provided sera were tested at several dilutions to prevent prozone effects; 0/218 false negatives (greater than 12 IU/ml). Only one evidently false positive result was seen in the 1000 samples tested. The DA test gave no false negative results but produced 23/773 false positives. After repeat testing there were 9/1000 sera which gave equivocal results which were negative by the Captia Toxo IgG test (less than 12 IU/ml) but with low titres of 16 in the Toxoreagent test or 4 IU/ml in the DA test. In this situation women would have been asked for a follow up sample for repeat testing. Only 300 sera were tested by Toxenz-G; initial screening produced 4/58 false negative results and 4/242 false positives.

CONCLUSIONS

The Captia Toxo IgG test gave the fewest discordant results on initial screening. Results could be readily expressed in international units using a programmable plate reader, and this may be useful for epidemiological studies. The Toxoreagent test is considerably cheaper, and is a simple and reliable method for screening provided that at least two dilutions are used.