Genital herpes in pregnancy: risk factors associated with recurrences and asymptomatic viral shedding

Viral infections during pregnancy

Viral infections during pregnancy have long been considered benign conditions with a few notable exceptions, such as herpes virus. The recent Ebola outbreak and other viral epidemics and pandemics show how pregnant women suffer worse outcomes (such as preterm labor and adverse fetal outcomes) than the general population and non-pregnant women. New knowledge about the ways the maternal-fetal interface and placenta interact with the maternal immune system may explain these findings. Once thought to be 'immunosuppressed', the pregnant woman actually undergoes an immunological transformation, where the immune system is necessary to promote and support the pregnancy and growing fetus. When this protection is breached, as in a viral infection, this security is weakened and infection with other microorganisms can then propagate and lead to outcomes, such as preterm labor. In this manuscript, we review the major viral infections relevant to pregnancy and offer potential mechanisms for the associated adverse pregnancy outcomes.

Herpes simplex virus 2 infection: molecular association with HIV and novel microbicides to prevent disease

Infection with herpes simplex viruses is one of the most ancient diseases described to affect humans. Infection with these viruses produces vexing effects to the host, which frequently recur. Infection with herpes simplex viruses is lifelong, and currently there is no vaccine or drug to prevent or cure infection. Prevalence of herpes simplex virus 2 (HSV-2) infection varies significantly depending on the geographical region and nears 20 % worldwide. Importantly, HSV-2 is the first cause of genital ulcers in the planet. HSV-2 affects approximately 500 million people around the globe and significantly increases the likelihood of acquiring the human immunodeficiency virus (HIV), as well as its shedding. Thus, controlling HSV-2 infection and spread is of public health concern. Here, we review the diseases produced by herpes simplex viruses, the factors that modulate HSV-2 infection, the relationship between HSV-2 and HIV and novel therapeutic and prophylactic microbicides/antivirals under development to prevent infection and pathological outcomes produced by this virus. We also review mutations associated with HSV-2 resistance to common antivirals.

Pregnancy and susceptibility to infectious diseases

To summarize the literature regarding susceptibility of pregnant women to infectious diseases and severity of resulting disease, we conducted a review using a PubMed search and other strategies. Studies were included if they reported information on infection risk or disease outcome in pregnant women. In all, 1454 abstracts were reviewed, and a total of 85 studies were included. Data were extracted regarding number of cases in pregnant women, rates of infection, risk factors for disease severity or complications, and maternal outcomes. The evidence indicates that pregnancy is associated with increased severity of some infectious diseases, such as influenza, malaria, hepatitis E, and herpes simplex virus (HSV) infection (risk for dissemination/hepatitis); there is also some evidence for increased severity of measles and smallpox. Disease severity seems higher with advanced pregnancy. Pregnant women may be more susceptible to acquisition of malaria, HIV infection, and listeriosis, although the evidence is limited. These results reinforce the importance of infection prevention as well as of early identification and treatment of suspected influenza, malaria, hepatitis E, and HSV disease during pregnancy.

Neonatal herpes simplex virus infection

Neonatal herpes, seen roughly in 1 of 3000 live births in the United States, is the most serious manifestation of herpes simplex virus (HSV) infection in the perinatal period. Although acyclovir therapy decreases infant mortality associated with perinatal HSV transmission, development of permanent neurological disabilities is not uncommon. Mother-to-neonate HSV transmission is most efficient when maternal genital tract HSV infection is acquired proximate to the time of delivery, signifying that neonatal herpes prevention strategies need to focus on decreasing the incidence of maternal infection during pregnancy and more precisely identifying infants most likely to benefit from prophylactic antiviral therapy.

Preventing neonatal transmission of herpes simplex virus

Herpes simplex virus (HSV) infections are highly prevalent and may have devastating consequences if transmitted to newborns. The highest risk of transmission is when the mother has primary HSV infection (rather than recurrence of chronic infection) late in pregnancy. Clinicians should obtain a careful history, performing serologic testing and counseling as appropriate. Delayed diagnosis of neonatal HSV is associated with high mortality. Even with adequate treatment, permanent sequelae, such as cerebral palsy and developmental delay, may occur. Clinicians should develop prudent strategies to avoid primary HSV acquisition during pregnancy, and provide prophylaxis or treatment when indicated.

Cervical antibodies to herpes simplex virus proteins in pregnancy and puerperium: a pilot study

Objective: This study was undertaken to evaluate the changes in total and anti-herpes simplex virus (HSV)-specific cervical IgA and IgG antibody profiles during and after pregnancy.

Methods: Serum and cervical secretions were obtained from pregnant patients before 20 weeks gestation, at 34–36 weeks gestation, and at 6 weeks postpartum and tested for total IgA and IgG antibody and for IgA and IgG to HSV proteins by Western blot.

Results: Seven women were HSV seronegative, 14 HSV-1 seropositive, and 14 HSV-2 ± HSV-1 seropositive. Minimal changes in the serum anti-HSV profiles were seen over the 3 visits. The total cervical IgA, IgG, and protein levels did not change between the 2 pregnancy visits but tended to increase at the postpartum visit. No consistent change in cervical HSV-specific IgA and IgG was seen during pregnancy, but the levels increased markedly at the postpartum visit.

Conclusions: Lower cervical anti-HSV antibody levels may be related to the previously reported increased frequency of a reactivation of HSV during late pregnancy. Further evaluation is necessary to confirm and quantify the changes in genital immunity during pregnancy and to evaluate whether the increased levels at the postpartum visit are sustained.

17-beta estradiol promotion of herpes simplex virus type 1 reactivation is estrogen receptor dependent

Correlations between estrogen and herpes simplex virus (HSV) reactivation from latency have been suggested by numerous clinical reports, but causal associations are not well delineated. In a murine HSV-1 corneal infection model, we establish 17-beta estradiol (17-betaE) treatment of latently infected ovariectomized mice induces viral reactivation, as demonstrated by increased viral load and increased immediate-early viral gene expression in the latently infected trigeminal ganglia (TG). Interestingly, the increased HSV reactivation occurred in the absence of inhibition of viral specific CD8(+) T-cell effector function. 17-betaE administration increased HSV reactivation in CD45(+) cell-depleted TG explant cultures, providing further support that leukocyte-independent effects on latently infected neurons were responsible for the increased reactivation. The drug-induced increases in HSV copy number were not recapitulated upon in vivo treatment of latently infected estrogen receptor alpha-deficient mice, evidence that HSV reactivation promoted by 17-betaE was estrogen receptor dependent. These findings provide additional framework for the emerging conceptualization of HSV latency as a dynamic process maintained by complex interactions among multiple cooperative and competing host, viral, and environmental forces. Additional research is needed to confirm whether pregnancy or hormonal contraceptives containing 17-betaE also promote HSV reactivation from latency in an estrogen receptor-dependent manner.

Neonatal herpes simplex virus infection

Herpes simplex virus (HSV) infection in the neonate is a rare event with severe consequences for the child even if adequately treated with antiviral drugs. Mothers with primary genital herpes infections late in pregnancy or at delivery have a high risk of transferring the infection to the child, while the risk of transfer in mothers with recurrent genital infections is only a few percent. Neonatal herpes localized in skin-eye-mouth has no mortality and morbidity after antiviral treatment. In neonatal disseminated and central nervous system disease, early treatment is a predictor for better outcome. The morbidity in survivors is high; after herpes encephalitis, only one-third of children have normal development. While awaiting vaccines or reliable predictors for prevention of neonatal herpes, clinical awareness of primary maternal herpes during pregnancy and recommendations for prophylactic treatment are important tools. For pediatricians the differential diagnosis of a child aged two to four weeks with seizures, neonatal herpes encephalitis must be considered and either excluded or treated. Neurological follow-up and training programs to minimize the consequences of a disability are important clinical aspects.

Reproductive tract infections in HIV positive women: A case control study

BACKGROUND

Human immunodeficiency virus (HIV) infection primarily affects women during their reproductive years, and the coexistence of reproductive tract infections (RTIs) is not surprising given the fact that HIV is mainly acquired via heterosexual contact.

AIM

The aim of the study was to compare the occurrence of RTIs among infected and noninfected women.

MATERIALS AND METHODS

A case control study of 83 HIV positive women, tested by two enzyme linked immunosorbent assay (ELISA) and a matched control of 87 HIV negative women were screened for RTIs. They were submitted to gynecological examination and cervical cytology.

RESULTS

The mean age for HIV positive women was 30 years and that for HIV negative women was 27 years. 18% HIV positive women had menstrual irregularities compared to 6% in seronegative group (P= 0.024). Vaginal infections including sexually transmitted infections (STIs) were found in 47 (57%) HIV positive women and 30 (34%) HIV negative women (P= 0.0037). Vaginal candidiasis was the most common infection (34%) in HIV positive women, followed by trichomoniasis (12%). Human papilloma virus (HPV) infection was seen in nine HIV positive women versus none in HIV negative women. Cervical cytology showed inflammation in 53 (64%) HIV positive women compared to 27 (31%) HIV negative women (P= 0.000023). Genital neoplasia, including carcinoma in situ was observed in 2 (2.5%) HIV positive women and in none of the HIV negative women.

CONCLUSION

It is seen that reproductive tract morbidities are common in HIV positive women. So it is imperative that HIV positive women have a complete gynecological evaluation including a Papanicolaou (PAP) smear with aggressive screening of STIs.

Understanding herpes simplex virus: transmission, diagnosis, and considerations in pregnancy management

Genital herpes simplex virus (HSV) infections are frequently asymptomatic or undiagnosed, but more than half the US population is seropositive for HSV, and about one-fifth are positive for HSV-2. These two factors contribute to the risk for sexual transmission and therefore to the risk of late-pregnancy acquisition of HSV. Most neonatal herpes infections are the result of undiagnosed, new-onset HSV infection in the mother. This article reviews the epidemiology of HSV, risks of transmission, and testing and management of HSV during pregnancy. Options for evaluation and management are presented.

Recrudescent herpes labialis during and prior to early pregnancy

OBJECTIVES

To assess the experience of recrudescent herpes labialis (RHL) before and during early pregnancy.

METHODS

History of RHL prior to and during the first trimester of pregnancy was obtained from 3738 women attending at 10-15 weeks' gestation. The influence of age, ethnicity, socioeconomic group, smoking behavior, and alcohol intake on RHL was assessed.

RESULTS

1066 women (28.5%) reported a history of RHL lesions, with reduced incidence of RHL during pregnancy (0.111 lesions/subject per month) compared with outside pregnancy (0.19 lesions/subject per month) (P<0.0001). Those who did report lesions during pregnancy (n=296) experienced them at a higher monthly rate (0.41 lesions/subject per month) than before pregnancy (0.25 lesions/subject per month) (P<0.0001). RHL rate in early pregnancy was related solely to the previous rate of lesion recrudescence (P<0.001).

CONCLUSION

Pregnant women with a history of RHL report reduced incidence of RHL during pregnancy.

Testing for HSV-2 infection among pregnant teens: implications for clinical practice

OBJECTIVES

To pilot test the feasibility of screening pregnant teens for HSV-2 infection during their first prenatal visit.

STUDY DESIGN

A cross-sectional study of 127 African-American adolescent females recruited during their first attendance to a prenatal clinic in a large urban hospital. A rapid serologic test (POCkit, manufactured by Diagnology Inc.) was used to assess HSV-2. The test uses a membrane-based immunoassay to detect circulating IgG antibodies to a specific antigen obtained from HSV-2 (semi-purified glycoprotein G2).

RESULTS

More than one-fifth (21.3%) of the adolescents tested positive for HSV-2; only 1 adolescent was previously aware of her infection. Older adolescents and those reporting a history of other STDs were significantly more likely to test positive for HSV-2.

CONCLUSIONS

Testing for HSV-2 in early pregnancy may be an efficient strategy for (1) initiating patient education designed to promote adoption of protective behaviors among adolescents at risk of HSV-2 acquisition during the remainder of their pregnancy and (2) teaching those who test positive how to recognize symptoms of HSV-2 outbreaks; patients reporting recurrent outbreaks during pregnancy may benefit from predelivery assessment.

Acyclovir suppression to prevent recurrent genital herpes at delivery

OBJECTIVE

To determine if suppressive acyclovir near term decreased the frequency of clinical recurrences at delivery in women with recurrent genital herpes simplex virus (HSV) infection.

METHODS

We conducted a prospective, double-blind, randomized trial in 234 women with recurrent genital herpes. Women with genital infection of any frequency were enrolled. Patients received either suppressive oral acyclovir 400 mg three times daily or an identical placebo after 36 weeks' gestation. Clinical lesions were identified, and HSV cultures were obtained at delivery. The frequencies of clinical and subclinical HSV recurrences at delivery were evaluated.

RESULTS

Six percent of patients treated with acyclovir, and 14% of patients treated with placebo had clinical HSV at delivery (p = 0.046). No patients in the acyclovir group had positive HSV cultures, compared with 6% of placebo-treated patients (p = 0.029). There was no significant difference in subclinical HSV shedding in the acyclovir group (0%) compared with the placebo-treated group (3%) (p = 0.102).

CONCLUSIONS

Suppressive acyclovir therapy significantly decreased the incidence of clinical genital herpes and the overall incidence of HSV excretion at delivery in patients with previous herpes infection.

Current recommendations for the treatment of genital herpes

The incidence of genital herpes continues to increase in epidemic-like fashion. Aciclovir (acyclovir) has been the original gold standard of therapy. The recent addition of famciclovir and valaciclovir as antiherpes drugs has improved convenience as well as the efficacy of treatment. Although aciclovir remains a widely prescribed and reliable drug, its administration schedule falls short of the ease of usage that the newer nucleoside analogues offer, for both episodic and suppressive therapy. Suppression of symptomatic disease and asymptomatic shedding from the genitalia have both become popular approaches, if not the primary targets of antiviral therapy. Knowing that asymptomatic disease leads to most cases of transmission strongly suggests that suppression with antiviral agents could reduce transmission risk in discordant couples. Unfortunately, the role for antivirals in reducing transmission remains to be proven in clinical trials. Neonatal herpes is now successfully treated using aciclovir. Current randomised clinical trials are examining aciclovir and valaciclovir administration, as well as safety and efficacy for post-acute suppressive therapy. Prevention of recurrences in pregnancy is also a topic under investigation, with a view to reducing the medical need for Cesarean section, or alternatively (and far less likely to be accomplished) to protect the neonate. Although resistance is largely limited to the immunocompromised and a change in resistance patterns is not expected, several drugs are available for the treatment of aciclovir-resistant strains of herpes simplex. Foscarnet is the main alternative with proven efficacy in this setting. Unfortunately, administration of foscarnet requires intravenous therapy, although a single anecdote of topical foscarnet efficacy in this setting has been published. Alternatives include cidofovir gel, which is not commercially available but can be formulated locally from the intravenous preparation. Less effective alternatives include trifluridine and interferon. Future possibilities for treatment of genital herpes include a microparticle-based controlled-release formulation of aciclovir and resiquimod (VML-600; R-848). The search for an effective therapeutic vaccine for genital herpes has not been successful to date, although a live virus glycoprotein H-deficient (DISC) vaccine is currently in clinical trials. Recent data suggest that seronegative women are protected (albeit, not fully) by a glycoprotein D recombinant vaccine with adjuvant. Despite the established safety and convenience of current treatment options, better suppressive options and topical treatment options are much needed. Studies using existing agents as potential tools to avoid Cesarean section, or transmission to neonate or partner are ongoing. Both vaccines and antivirals may eventually play a role in prevention of infection.

HSV-2 specific serology should be offered routinely to antenatal patients

The most devastating consequence of genital herpes is neonatal herpes. It is clear that the majority of newborns acquire their infection by contact with infected genital secretions during delivery from an asymptomatic mother who acquired a first episode of genital herpes near the time of labour. Since the majority of cases of first episode genital herpes during pregnancy are unrecognised, the prevention of neonatal transmission will depend upon the identification of the HSV serologically discordant couple and the institution of appropriate interventions by mid pregnancy. Therefore, the précis of this discussion paper is that universal HSV serological testing should be performed at the first prenatal visit. As a corollary, type specific HSV serology will need to be commercially available and relatively inexpensive. In any country, pregnant women and their partners represent a broad, cross section of sexually active adults. The vast majority present themselves to the health care system for care during their pregnancies which is a period of time in which the focus of care is primarily preventive and during which women are generally motivated and compliant. This is truly the 'golden opportunity' to identify patients already infected as well as those at risk for acquiring genital herpes. Information regarding genital herpes and methods of preventing transmission to susceptible partners and newborn infants can easily be added to educational programmes which have already become an institution within prenatal care.

Genital herpes complicating pregnancy

The seroprevalence of herpes simplex virus type 2 (HSV-2) infections among reproductive-aged women in the United States in prevalent. This article discusses HSV and how it effects the pregnant women and neonates. Management of the disease is reviewed, and recommendations for management of HSV during pregnancy are given.

Herpes simplex virus seropositivity and reactivation at delivery among pregnant women infected with human immunodeficiency virus-1

OBJECTIVE

Our purpose was to determine whether pregnant women infected with human immunodeficiency virus-1 have an increased risk of herpes simplex virus-2 seropositivity and herpes simplex virus reactivation at delivery.

STUDY DESIGN

Sixty women infected with human immunodeficiency virus and 8408 other patients who were delivered at the University of Washington between 1989 and 1995 had herpes simplex virus serologic determinations at delivery. Genital herpes simplex virus cultures were obtained for 48 (80%) of the human immunodeficiency virus-infected women and 5567 (66%) of the controls. Logistic regression was used to adjust for possible confounding factors.

RESULTS

Forty-five (75%) of human immunodeficiency virus-infected women and 2709 (32%) controls were seropositive for herpes simplex virus-2 (p < 0.0001). Eight percent of human immunodeficiency virus-infected women and 2% of controls had herpes simplex virus reactivation in labor (p < 0.05).

CONCLUSIONS

Infection with herpes simplex virus-2 is common among pregnant women infected with human immunodeficiency virus. Herpes simplex virus reactivation complicates labor in this group more often than in other obstetric patients. The role of herpes simplex virus in perinatal human immunodeficiency virus transmission warrants further study.

Perinatal herpesvirus infections. Herpes simplex, varicella, and cytomegalovirus

The herpesvirus infections (herpes simplex, varicella, and cytomegalovirus) create many dilemmas when encountered during pregnancy. This article reviews the epidemiologic diagnosis and management of perinatal herpesvirus infections. A review of possible future trends is also included.

Herpes simplex virus type 2 detection by culture and polymerase chain reaction and relationship to genital symptoms and cervical antibody status during the third trimester of pregnancy

OBJECTIVES

Our goal was to define the frequency of asymptomatic herpes simplex virus type 2 shedding by culture and polymerase chain reaction and to correlate our findings with cervical anti-herpes simplex virus type 2 immunoglobulin A production.

STUDY DESIGN

Women who were seropositive for herpes simplex virus type 2 collected daily genital tract samples during the third trimester for culture and deoxyribonucleic acid quantitation by polymerase chain reaction. Cervical secretions were collected weekly for anti-herpes simplex virus type 2 immunoglobulin A. Asymptomatic shedding by culture versus polymerase chain reaction and anti-herpes simplex virus type 2 immunoglobulin A detection with and without genital shedding were compared by means of McNemar's chi 2 test.

RESULTS

Asymptomatic shedding was more frequent by polymerase chain reaction than by culture (13.8% vs 2.3%, p < 0.0001). When cervical anti-herpes simplex virus type 2 immunoglobulin A was present, patients were more likely to have negative results by polymerase chain reaction than positive results (66.7% vs 26.7%, p = 0.001). Anti-herpes simplex virus type 2 immunoglobulin A was detected beyond 37 weeks in only one subject.

CONCLUSIONS

Polymerase chain reaction was more sensitive than culture for detecting asymptomatic genital herpes simplex virus. The role of immunoglobulin A in clearing genital herpes simplex virus remains to be determined.

Selected issues in premature rupture of the membranes: herpes, cerclage, twins, tocolysis, and hospitalization

A number of issues related to premature rupture of the membranes (PROM) are less common or have not been thoroughly evaluated. Genital herpes simplex colonization carries the potential for significant perinatal morbidity, particularly with primary infection and membrane rupture. Cervical cerclage is both a risk factor for preterm PROM (pPROM) and confounds the management of women with PROM. Twin gestations carry an increased risk of pPROM and earlier membrane rupture. Membrane rupture can involve the presenting or nonpresenting sac. In each case, the fetus with intact membranes is at risk due to brief latency or intrauterine infection after membrane rupture of its sibling. Prophylactic and therapeutic tocolysis remains controversial because of the high risk of intrauterine infection after PROM, and the lack of data demonstrating long-term efficacy. With increased attention to health care costs, home management of pPROM has recently been suggested as an alternative to hospitalization after pPROM. This article reviews the clinical course and management options regarding these issues. Also discussed are those issues for which there is controversy but little available data. Each of these issues offers fruitful ground for discussion and further study.

Virologic characteristics of subclinical and symptomatic genital herpes infections

BACKGROUND

The frequency, pattern, and anatomical sites of subclinical shedding of herpes simplex virus (HSV) in the genital tract, along with factors that predict such shedding, have not been well characterized.

METHODS

We studied prospectively the clinical and virologic course of genital herpes in 110 women. The women kept symptom diaries and provided daily samples from the vulva, cervix, and rectum for viral culture.

RESULTS

During a median follow-up of 105 days, subclinical shedding of virus was identified in 36 of 65 women (55 percent) with HSV type 2 (HSV-2), in 16 of 31 women (52 percent) with HSV type 1 (HSV-1) and HSV-2, and in 4 of 14 women (29 percent) with only HSV-1. Among women with genital HSV-2 infection, subclinical shedding occurred on a mean of 2 percent of the days. The mean duration of viral shedding during subclinical episodes was 1.5 days, as compared with 1.8 days during symptomatic episodes. HSV was isolated from several sites in the genital tract and rectum in 17 percent of subclinical episodes and 22 percent of symptomatic episodes. Half the episodes of subclinical shedding of HSV occurred within seven days of a symptomatic recurrence. The risk of subclinical shedding increased with the frequency of symptomatic recurrences. Subclinical shedding was more frequent among women with more than 12 recurrences per year than among those with no symptomatic recurrences (odds ratio, 3.3; 95 percent confidence interval, 1.4 to 7.9); it was also more frequent among women who had recently acquired genital herpes (odds ratio for women with HSV acquired in the past year as compared with those who had had the infection for a year or more, 1.85; 95 percent confidence interval, 1.1 to 3.1).

CONCLUSIONS

Among women with a history of genital herpes infection, subclinical shedding of HSV is common and accounts for nearly one third of the total days of reactivation of HSV infection in the genital tract. Women with frequent symptomatic recurrences also have frequent subclinical shedding and may be at high risk for transmitting HSV.

Susceptibility to herpes labialis following multiple experimental exposures to ultraviolet radiation

We studied susceptibility to herpes labialis by exposing 20 volunteers to experimental ultraviolet radiation (UVR) on three occasions at 3- to 4-month intervals. The number of patients who developed lesions after each session was 9/20 (45%), 9/20 (45%) and 14/20 (70%). Herpes simplex virus (HSV) was isolated from 21/29 (72%) of lesions sampled. Three patients never developed a lesion, 13 developed lesions on one or two of the three occasions, and 4 patients had a lesion following all three sessions. Seven of 33 (21%) lesions were 'immediate' lesions (developed within 48 h) and the others developed 3-7 days after UVR exposure (delayed lesions). Development of lesions correlated with historical susceptibility to sun-induced herpes labialis, but not with age, sex, years with herpes labialis, frequency of herpes labialis from all causes, or concurrent serum levels of cortisol, dehydroepiandrosterone, estradiol, progesterone or alpha 1-antitrypsin. Among normally menstruating females, a significant association was identified between the development of herpes labialis and the luteal phase of the menstrual cycle (8 cases of herpes labialis/11 attempts, RR = 14, P = 0.005). The lack of correlation between episodes of natural herpes labialis and susceptibility to experimental UVR-induced disease suggests that these events are controlled differently. The results of serial attempts to induce experimental herpes in each patient was most commonly inconsistent, indicating that individual patient susceptibility to UVR varies over time. While the explanation for this variation remains unclear, stages of the menstrual cycle may be important among women.

Herpes simplex virus infection in pregnancy and its management

Neonatal herpes simplex virus (HSV) infection is considered to be rare in the UK, affecting less than 3 per 100,000 live births, but the true incidence is probably higher due to under-reporting. In contrast, neonatal HSV infection is more common in the USA affecting 1 per 7500 live births overall. Infection in neonates is frequently serious and may be fatal.

Natural killer cell cytotoxicity to herpes simplex virus-1-infected cells is not altered by pregnancy

There is evidence to suggest a decrease in natural killer cell cytotoxicity during pregnancy, but information regarding immune responsiveness to actual infection is limited. An in vitro study was undertaken to examine the effect of herpes simplex virus infection on natural killer cell cytotoxicity with peripheral blood mononuclear cells from pregnant (N = 8) and nonpregnant (N = 5) women. The peripheral blood mononuclear cells were separated by Ficoll-Hypaque centrifugation. Effector cells were incubated with live herpes simplex virus-1, ultraviolet-inactivated herpes simplex virus-1, or media alone for 18 hours at 37 degrees C. K562 target cells were used in a sodium chromate release assay with an effector-to-target cell ratio of 100:1. Baseline natural killer cell values (mean +/- SE) for pregnant patients (13.4% +/- 2.4%) and nonpregnant patients (19.8% +/- 3.7%) were similar. Natural killer cell cytotoxicity was significantly increased by incubation with live virus for both pregnant (37.5% +/- 6.2%) and nonpregnant subjects (49.8% +/- 7.6%). There was no difference in mean values between media and ultraviolet-inactivated herpes simplex virus-1-exposed samples for either group. Results suggest that (1) infection with live virus, but not viral antigen alone, can augment natural killer cell response in vitro and (2) natural killer cell response to herpes simplex virus-1 infection is not altered by pregnancy.

Management of genital herpes simplex infection

Herpes simplex infection of the genitals is a common condition, more often due to herpes simplex virus (HSV) type 2 than to type 1 virus. There is a severe first attack followed by mild recurrences which are more common and more frequent after HSV-2 than after HSV-1 genital infection. Clinical features with prodrome, vesicles and erosions may be characteristic allowing rapid clinical diagnosis. When possible laboratory confirmation should be attempted. General management includes simple hygiene, avoidance of sexual transmission, use of condoms, and notifying partners. Oral acyclovir (Zovirax, Wellcome) is the drug of choice for initial attacks and should be considered for all women with this diagnosis. Intravenous acyclovir may be used for very severe attacks. Men with initial attacks may be treated with oral acyclovir but mild disease affecting only skin may be treated with 5% acyclovir cream. Recurrences are short so acyclovir has less effect. Frequent recurrences can be troublesome and may be suppressed by continuous oral acyclovir, or individual attacks may be aborted with intermittent therapy. Various systemic complications may occur; an important but rare problem is primary herpes in late pregnancy. Acyclovir is effective in the treatment of the troublesome herpes simplex disease associated with human immunodeficiency infection. Acyclovir is one of the more expensive treatments for sexually transmitted diseases. At present in many countries costs are being examined, and application of the principles outlined here should help to minimize cost and maximize care.

Immune modulation of natural killer cell cytotoxicity against herpes infected target cells in pregnancy

Natural killer cell cytotoxicity (NKC) is a nonspecific, primary immunodefense system active against a variety of pathogens, including herpes simplex virus (HSV). Evidence suggests that during pregnancy, NKC is attenuated. The regulatory mechanisms for this immune attenuation have yet to be defined. We examined two cytokines (interleukin-2 [IL-2] and alpha interferon [IFN]) for their ability to alter NKC responsiveness during pregnancy, utilizing an HSV-infected target cell model. Peripheral mononuclear effector cells were isolated from 19 pregnant and 19 nonpregnant subjects by Ficoll-Paque separation. These cells were incubated with IFN, IL-2, or media alone, and analyzed for %NKC by an 18 h chromium release assay. The percentage of NKC was lower using the effector cells from the pregnant subjects as compared to nonpregnant controls. Incubation with either IFN or IL-2 resulted in a significant augmentation of NKC in both the pregnant and nonpregnant derived cells. There were no differences in IL-2 dose requirements or levels of cytotoxicity achieved (43.1 +/- 6.8% vs. 44.4 +/- 6.8%, respectively) between pregnant and nonpregnant derived cells. The IFN-mediated augmentation of NKC was somewhat blunted in pregnancy both in terms of absolute levels of cytotoxicity achieved (26.1 +/- 3.9% vs. 37.2 +/- 4.9%, respectively) and dose response curves generated. These results demonstrate that NKC against HSV infected cells is attenuated during pregnancy and can be immunoregulated with the use of either IFN and IL-2. The restoration of NKC responsiveness with IFN, however, remains incomplete during pregnancy, suggesting that this cytokine's mechanism of action differs from that of IL-2.

Asymptomatic herpes simplex virus shedding from the genital tract whilst on suppressive doses of oral acyclovir

Forty-eight patients were recruited into a study of continuous oral acyclovir therapy for the suppression of recurrent genital herpes simplex virus (HSV) infection. Seven of these patients were shown to shed HSV in the absence of clinical signs or symptoms whilst on medication. The asymptomatic shedders did not differ significantly from the rest of the group in terms of age, interval from first attack to enrollment or number of recurrences prior to enrollment. Only one patient admitted to poor compliance as a trigger to asymptomatic HSV shedding. Failure to suppress asymptomatic shedding during prophylactic acyclovir therapy may have implications for sexual transmission to partners and vertical transmission to neonates and requires further study.

Screening pregnant women for genital herpes

Neonatal herpes leads to serious morbidity and high mortality. The true incidence is unknown due to under reporting and difficulties in diagnosing the condition, but may be increasing. Mothers with primary disease, at term, present a greater infection risk to their offspring than mothers with recurrent disease, but the exact risks remain unknown. Existing prevention policies are inefficient, time-consuming for the doctor and the patient and, where caesarean section is offered to at-risk mothers, potentially hazardous. Anti-viral therapy offers a rational alternative and requires urgent evaluation.

Natural killer cell cytotoxicity and antibody-dependent cellular cytotoxicity to herpes simplex virus-infected cells in human pregnancy

Natural killer cell (NKC) cytotoxicity and antibody-dependent cellular cytotoxicity (ADCC) represent the ability of human leukocyte effector cells to destroy target cells in the absence and presence of antibody, respectively. Since these immune systems play a pivotal role in the body's primary lines of defense against a variety of pathogens including herpes simplex virus (HSV), a study was undertaken to evaluate the influence of pregnancy on these systems. Eleven uncomplicated gravidas were followed serially through each trimester and compared to 11 nonpregnant female controls. Mononuclear cells were acquired by Ficoll-Hypaque centrifugation of heparinized blood. Chang liver cells infected with HSV-I were utilized as target cells in a 51Cr release assay. Mean NKC values in the pregnant patients were uniformly lower than in the controls. No similar decreases in ADCC activity were observed in a comparison between the two study populations. These data support previous observations suggesting that pregnancy represents a relatively immunocompromised state. Differences apparently exist between NKC and ADCC effector cell populations with regard to the influence of pregnancy. Although these physiologic alterations in immunoregulation may help support the fetoplacental allograph, detrimental conditions may exist regarding susceptibility to various pathogens such as HSV.

Perinatal viral infections

In comparison to older children and adults, neonates are immunologically incompetent. They are susceptible to infections caused by a variety of microorganisms, including bacteria, fungi and viruses. These infectious agents may be acquired by neonates either prenatally, during the intrapartum period or postnatally. The purpose of this review is to emphasize the potential impact of viral infections contracted by neonates at the time of delivery or within the neonatal period. The viruses reviewed include the herpes group of viruses (cytomegalovirus, herpes simplex viruses and varicella-zoster virus), type B hepatitis virus, human immunodeficiency virus, respiratory viruses, enteroviruses, rotavirus and human papilloma virus. For each virus the potential sources and incidence of the infection, the common manifestations of the illness, and possible means of prevention and therapy are discussed. Although infections caused by bacteria tend to be more clinically dramatic and more immediately life-threatening, it is emphasized that infections caused by viruses are common and associated with substantial long-term morbidity. Perinatal viral infections need to be recognized as early in life as possible so that their natural history can be more completely defined and any possible intervention made.

Intrauterine latent herpes simplex virus infection: I. Spontaneous abortion

Herpes simplex virus (HSV, probably type 2) antigen was detected in nonpregnant and pregnant endometria, placentae, umbilical cords, and neonatal tissues (companion paper) by avidin-biotin complex immunohistochemical studies. HSV cytologic abnormalities were not detected in any of the 380 cases examined: included were specimens from therapeutic and spontaneous abortions (200 cases) and endometrial curettage (180 cases). The presence of inflammation was not correlated with HSV positivity. Endometrial HSV positivity was significantly correlated with normal late secretory phase (40 per cent of specimens positive), abnormal secretory phase (67 per cent positive), and therapeutic (33 per cent positive) versus spontaneous (26 per cent positive) abortions. Placental HSV positivity was significantly correlated with spontaneous (39 per cent positive) versus therapeutic (14 per cent positive) abortions and with blighted ova (67 per cent positive). No significant correlation was found between HSV positivity and a clinical history of oral or genital HSV infection in either the patient or the male partner. The data support the concept of a subclinical latent intrauterine endometrial HSV infection that is hormonally regulated and can produce transplacental infection of the embryo or fetus, with variable consequences.

Intrauterine latent herpes simplex virus infection: II. Latent neonatal infection

Herpes simplex virus (HSV, probably type 2) antigen has been detected in endometria and abortion tissue (companion paper) and in placentae, umbilical cords, and fetal and neonatal organs by avidin-biotin complex immunohistochemical studies. HSV cytologic abnormalities were not detected in any of the 12 normal and 64 abnormal cases analyzed, nor was HSV detected by culture or electron microscopy in selected cases. Antigen was present in single epithelial and, rarely, mesenchymal cells of various organs. Clinically unexplained fetal or neonatal problems associated with HSV antigen positivity included intrauterine death, fetal growth retardation, cystic brain degeneration, hydrops, interstitial pneumonitis, necrotizing enterocolitis, hepatitis, encephalitis, myocarditis, and renal failure. Maternal floor infarct of placenta and calcifying funisitis are the manifestations of intrauterine HSV infection in most cases. Maternal history of HSV infection was uncommon. It is concluded that intrauterine HSV infection may persist in the fetus and neonate in a latent fashion without cytologic abnormalities or detectable virus. This latent infection may be associated with intrauterine and neonatal death, organ damage, and neonatal disease.

Failure of antepartum maternal cultures to predict the infant's risk of exposure to herpes simplex virus at delivery

In 414 pregnant women with a history of recurrent genital herpes simplex infection, we studied the correlation between asymptomatic viral shedding in late pregnancy and at the time of delivery. Antepartum cultures for asymptomatic reactivation of herpes simplex virus were positive in 17 of the 414 women (4.1 percent). None of these women had positive cultures at the time of delivery. Cultures of specimens obtained at delivery from 5 of 354 asymptomatic mother-infant pairs (1.4 percent) were positive for asymptomatic excretion of herpes simplex virus. None of these women had had antepartum cultures that documented asymptomatic excretion of herpes simplex virus, despite the fact that culturing was repeatedly performed during the four weeks before delivery. Asymptomatic shedding of herpes simplex virus occurred with the same frequency at delivery, whether or not any episodes of symptomatic recurrence were noted during the pregnancy (1.4 vs. 1.3 percent). We conclude that antepartum maternal cultures do not predict the infant's risk of exposure to herpes simplex virus at delivery.