Use of polymerase chain reaction for successful identification of asymptomatic genital infection with herpes simplex virus in pregnant women at delivery

Detection of Herpes Simplex Virus in Genital Specimens by Type-Specific Polymerase Chain Reaction

Viral isolation is the standard method for the detection of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) in clinical specimens. This study describes the development of a type-specific polymerase chain reaction (PCR) assay for detection and typing of HSV-1 and HSV-2, and a comparison of its sensitivity with that of isolation in a clinical setting. Specimens from patients presenting with genital ulcers were tested for the presence of HSV by both methods. Oligonucleotide primers were selected to enable type-specific amplification of HSV-1 and HSV-2 DNA. Conditions were optimized to allow detection and typing from a single reaction tube using a multi-primer PCR method. When compared with PCR, the sensitivity of isolation was 67% and the specificity 97%. This protocol allowed rapid, sensitive and accurate detection and typing of HSV with a single PCR assay.

Diagnostics for Herpes Simplex Virus

Herpes simplex virus (HSV) is one of the most common, yet frequently overlooked, sexually transmitted infections. Since the type of HSV infection affects prognosis and subsequent counseling, type-specific testing to distinguish HSV-1 from HSV-2 is recommended. Although PCR has been the diagnostic standard for HSV infections of the central nervous system, until now viral culture has been the test of choice for HSV genital infection. However, HSV PCR, with its consistently and substantially higher rate of HSV detection, will likely replace viral culture as the gold standard for the diagnosis of genital herpes in people with active mucocutaneous lesions, regardless of anatomic location or viral type. Alternatively, type-specific serologic tests based on glycoprotein G should be the test of choice to establish the diagnosis of HSV infection when no active lesion is present. Given the difficulty in making the clinical diagnosis of HSV, the growing worldwide prevalence of genital herpes and the availability of effective antiviral therapy, there is an increased demand for rapid, accurate laboratory diagnosis of patients with HSV.

Oral and vulvar changes in pregnancy

The endocrinologic, immunological, and vascular changes that occur during pregnancy are far-reaching. These systemic factors produce profound local impact on the physiology and pathology of the oral cavity, vagina, and vulva. Physiological changes can be expected and tolerable or of such severity that they are viewed as pathological. Existing disease can be exacerbated and dermatoses specific to pregnancy can erupt. Each of these conditions can pose potentially challenging treatment considerations.

Herpes simplex virus in pregnancy: new concepts in prevention and management

Genital herpes simplex virus (HSV) infection is one of the most common viral sexually transmitted diseases in the United States. It is estimated that 45 million adolescents and adults are infected with genital HSV. Most genital herpes infections in the United States are caused by HSV type 2 (HSV-2), and 25% to 30% of women of reproductive age have HSV-2 antibodies. What is more striking is that genital herpes is frequently under-recognized, and that only 5% to 10% of these women have a history of genital herpes. Because such a small percentage of women are aware of being infected with HSV, the risk of maternal transmission of this virus to the fetus or newborn is a significant health issue.

Spin-amplified culture followed by enzyme immunoassay for detection of herpes simplex virus in patient specimens: a comparative study

In a comparative study it was found that a combination technique of spin-amplified culture and detection of herpes simplex virus (HSV) antigen in 48-h incubated cell culture lysate by a HSV antigen detection enzyme immunoassay kit (Dupont Herpchek) detected the largest number (227) of confirmed HSV positives when compared to standard cell culture (191) and direct Herpchek (146) on the same 415 clinical specimens.

Prenatal testing for infectious disease

Prenatal testing for infectious diseases is performed frequently and for a variety of indications. The purpose of this article is to review the maternal and fetal infections that pose diagnostic concerns. Recent advances in diagnostic testing (such as avidity testing) is included. Testing issues focus on the diagnosis of maternal and fetal infection.

Herpes. Transmission and viral shedding

Herpes simplex virus infections are transmitted through contact with infected oral or genital secretions. The virus can be present on mucosa during a symptomatic recurrence or asymptomatically. Most transmissions to neonates and sexual partners occur during asymptomatic viral shedding. The frequency of viral isolation in the absence of lesions ranges from 2% to 6% of days; however, studies using more sensitive tests, such as polymerase chain reaction, show that viral shedding can occur on the average 28% of days.

Herpes simplex virus

Herpes simplex virus (HSV) infection is prevalent worldwide. Herpes labialis, caused predominantly by HSV-1, and herpes vulvovaginitis, caused predominantly by HSV-2, may result in significant morbidity and mortality for infected neonates exposed during delivery. The diagnosis of HSV infection is made by serological testing, viral culture, or polymerase chain reaction. Women with primary herpes vulvovaginitis exhibit a painful vesicular rash which is self-limited but may be followed by multiple recurrences. Women at greatest risk to transmit HSV to their neonates are those who experience their first episode of HSV during the latter stage of pregnancy. If infected, their neonates may have localized skin, eye and mucosal lesions, invasive central nervous system infection, or disseminated disease. Because of the potentially devastating outcome for a baby infected with HSV, pregnant women with active HSV lesions at delivery should be offered a cesarean section. Still, many neonates who are infected with HSV are born to women with asymptomatic HSV shedding. Therefore, prevention of HSV during pregnancy is exceedingly important.

Evaluation of a non-isotopic polymerase chain reaction assay for detection in clinical specimens of herpes simplex virus type 2 DNA. Canadian Women's HIV Study Group

BACKGROUND

PCR assays for detection of herpes simplex virus DNA sequences in clinical specimens are more sensitive than cell culture.

OBJECTIVE

A non-isotopic PCR assay (glycoprotein B HSV-2 assay, Roche Molecular Systems) for detection of HSV-2 DNA sequences was evaluated on 234 clinical specimens.

STUDY DESIGN

A total of 125 patients (73 women, 40 men, 12 unknown) provided 162 samples contained in viral transport medium. Samples were first inoculated in cell culture, centrifuged at 12,000 x g, lyzed and kept frozen. A total of 77 women provided 42 cervicovaginal lavages and 30 vaginal tampons that were lyzed, tested with two isotopic HSV-2 PCR assays and kept frozen. All these samples were subsequently thawed and amplified with the glycoprotein B HSV-2 assay using generic primers for HSV glycoprotein B gene. Amplicons were captured on microplates with a HSV-2-specific probe and were detected with avidin-peroxidase and substrate.

RESULTS

Of the 162 samples submitted to viral culture, HSV-2 was isolated from 73 while 89 did not contain HSV-2. All the 73 specimens with culture-proven HSV-2 infections tested positive with glycoprotein B HSV-2 assay (sensitivity of 100%). Herpesviruses other than HSV-2 were isolated from 34 samples that were negative with glycoprotein B HSV-2 assay. Two culture-negative samples tested positive in the glycoprotein B HSV-2 assay (specificity of 98.7%). The latter samples could not be retested in confirmatory isotopic HSV-2 PCR tests. HSV-2 DNA sequences could also be detected directly in cervical lavages or vaginal tampons from 13 women with the glycoprotein B HSV-2 assay.

CONCLUSION

Detection and typing of HSV-2 in clinical samples, including those collected in viral transport medium, can be accomplished with PCR assays using the AMPLICOR format.

Neonatal herpes in Denmark 1977-1991

BACKGROUND

To prevent neonatal herpes, women in labor with genital herpes infection are still delivered by Cesarean section. This policy is currently being debated. The aim of this study was to determine the incidence of neonatal herpes in Denmark and to evaluate the prevention practice.

METHODS

All newborns with perinatal herpes in Denmark 1977-1991 were identified from hospital-records.

RESULTS

Of 862,298 deliveries 136 possible cases were found but only 30 (22%) fulfilled the criteria for neonatal herpes. The incidence increased from 2.36 to 4.56 per 100,000 live births during 1977-1984 through 1984-1991. Three mothers (10%) had recurrent herpes at delivery, three (10%) had primary herpes, and five (17%) had oral herpes. Seven infants (23%) were delivered by Cesarean section. Nine (30%) only had cutaneous herpes, four (13%) had CNS herpes, nine (30%) had disseminated disease. Six (20%) did not have any sequelae. Four (13%) died. Six (20%) had serious neurological sequelae. Seven (23%) only had cutaneous recurrences. In seven cases (23%) information was insufficient.

CONCLUSIONS

During a 15 year period in Denmark only one neonate had serious sequelae following a recognized maternal herpes recurrence. Four infants had a serious infection in spite of Cesarean section. This study does not support a policy of Cesarean section in case of maternal recurrent herpes simplex infection at delivery.

Evaluation of a quantitative competitive PCR assay for measuring herpes simplex virus DNA content in genital tract secretions

Previous studies have shown an association between the approximate titer of herpes simplex virus (HSV) DNA in clinical specimens and the ability to isolate HSV from genital secretions. To control for variance in amplification conditions, we developed a competitive quantitative PCR (QC PCR) for the detection of HSV DNA. The assay accurately measured from 10 to 10(6) copies of HSV DNA. We compared the QC PCR with our previous semiquantitative detection method and found concordance for 61 of 63 positive specimens. We also evaluated the HSV DNA content from individual swabs of genital secretions obtained from individual sites of the genital tract (cervix, vulva, and rectum) with that from one swab with secretions from all three sites. The concordance for detecting HSV DNA was 91%; for only 4 of 143 collection days was there a > 1 log difference between the two collection methods. A single swab with secretions from all three genital sites and evaluated in a QC PCR format can accurately measure the frequency of subclinical and clinical shedding of HSV and the titer of HSV shed from the genital region. Such an approach should be very useful in the evaluation of antiviral chemotherapy for HSV.

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.

Prokaryotic DNA sequences in patients with chronic idiopathic prostatitis

Half of all men experience symptoms of prostatitis at some time in their lives, but the etiology is unknown for more than 90% of patients. Optimal clinical and culture methods were used to select 135 men with chronic prostatitis refractory to multiple previous courses of antimicrobial therapy. The subjects had no evidence of structural or functional lower genitourinary tract abnormalities of bacteriuria or bacterial prostatitis by traditional clinical tests, or of urethritis or urethral pathogens by culture. Specific PCR assays detected Mycoplasma genitalium, Chlamydia trachomatis, or Trichomonas vaginalis in 10 patients (8%). Broad-spectrum PCR tests detected tetracycline resistance-encoding genes, tetM-tetO-tetS, in 25% of patients and 16S rRNA in 77% of subjects. The tetM-tetO-tetS-positive cases constituted a subset of the 16S rRNA-positive cases. Patients with 16S rRNA were more likely to have > or = 1,000 leukocytes per mm3 in their expressed prostatic secretion than men whose prostate biopsy specimens were negative for 16S rRNA (P < 0.001). Based on direct sequencing and repetitive cloning, multiple sources of 16S rRNA were observed in individual patients. Sequences of 29 cloned PCR products revealed 16S rRNAs distinct from those of common skin and gut flora. These findings suggest that the prostate can harbor microorganisms that are not detectable by traditional approaches. These organisms may be associated with inflammation in the expressed prostatic secretions. Molecular methods hold great promise for identifying culture-resistant microorganisms in patients with chronic prostatitis.

Detection of viral DNA to evaluate outcome of antiviral treatment of patients with recurrent genital herpes

Culture of infectious virus, PCR amplification of viral DNA, and the appearance of genital skin lesions were used as markers to study the course of a recurrence of genital herpes in 40 patients treated with famciclovir or placebo. The highest frequency of patients with skin lesions occurred within the first 36 h following the onset of a recurrence, which also corresponded to the peak in the production of virus. While the timing of the peak in skin lesions was independent of the type of treatment, the frequency of lesions and the release of virus at the lesion site were both reduced by famciclovir treatment. Furthermore, patients receiving this antiviral agent showed a more rapid recovery time and a shorter period during which viral DNA could be detected at the lesion. PCR and then Southern blot hybridization greatly enhanced our ability to detect herpes simplex virus at the lesion site. This procedure proved to be of greater diagnostic value in assessing genital herpes than the standard culture method currently used. In addition, PCR was more sensitive in evaluating treatment effectiveness.

Simultaneous PCR detection of Haemophilus ducreyi, Treponema pallidum, and herpes simplex virus types 1 and 2 from genital ulcers

A multiplex PCR (M-PCR) assay with colorimetric detection was devised for the simultaneous amplification of DNA targets from Haemophilus ducreyi, Treponema pallidum, and herpes simplex virus (HSV) types 1 and 2. By using target-specific oligonucleotides in a microwell format, 298 genital ulcer swab specimens collected in New Orleans during three intervals from 1992 through 1994 were evaluated. The results of the M-PCR assay were compared with the results of dark-field microscopy and H. ducreyi culture on two different culture media. HSV culture results were available for 99 specimens collected during the third interval. Confirmatory PCR assays targeting different gene sequences for each of the three organisms were used to validate the M-PCR results. Specimens were resolved as positive for the determination of sensitivity if the reference diagnostic test was positive or if the results of both the M-PCR and the confirmatory PCR were positive. The resolved sensitivities of M-PCR for HSV, H. ducreyi, and T. pallidum were 100, 98.4, and 91%, respectively. The resolved sensitivities of HSV culture, H. ducreyi culture, and dark-field microscopy were 71.8, 74.2, and 81%, respectively. These results indicate that the M-PCR assay is more sensitive than standard diagnostic tests for the detection of HSV, H. ducreyi, and T. pallidum from genital ulcers.

Detection of the BC 24 transforming fragment of the herpes simplex virus type 2 (HSV-2) DNA in cervical carcinoma tissue by polymerase chain reaction (PCR)

The polymerase chain reaction (PCR) was used to investigate samples from Indonesian and Swedish patients with cervical intraepithelial neoplasia grade III (CIN III), squamous cell carcinoma or adenocarcinoma of the cervix for the presence of a transforming fragment (BC 24) of herpes simplex virus type 2 (HSV-2) DNA. The PCR test for HSV-2 DNA was more sensitive than the infectivity endpoint titer in a cell culture system and no cross reactivity was found with either varicella-zoster virus, cytomegalovirus, Epstein-Barr virus, human papillomavirus 16 or 18, or human genomic DNA. Using this PCR test, 2 out of 5 cases with CIN III, 10 of 71 squamous cell carcinomas, and 3 of 11 adenocarcinomas of the uterine cervix were found to contain DNA sequences homologous to the BC 24 fragment of the HSV-2 genome. Only two of the samples containing this transforming region of the HSV-2 DNA were positive in a PCR assay for the HSV-2 DNA polymerase gene. The great majority of the HSV-2 BC 24 DNA positive (12 of 15) came from the Indonesian group of patients. All 15 CIN III or cancer samples positive for the HSV-2 BC 24 fragment were also positive for papillomavirus DNA. In line with observations made by others, our data support the hypothesis that HSV infection could represent one of several possible oncogenic cofactors leading to cervical carcinoma. The HSV cofactor might be more important in the Indonesian than in the Swedish population.

Genital herpes and pregnancy--preventive measures

Genital herpes is particularly dangerous during pregnancy because of the risk of neonatal infection. This is discussed in four situations of genital herpes associated with pregnancy. Choosing the most appropriate method of delivery, i.e. carrying the least risk of transmission from mother to baby, is based on our knowledge of the natural history of genital herpes infection, the risk to the newborn (estimated from epidemiological studies), and, lastly, the possible preventive measures available.

Diagnosis of genital herpes by polymerase chain reaction amplification

A new polymerase chain reaction (PCR) method employing type-specific primers and probes was applied to 114 clinical specimens obtained from 58 female patients with genital lesions or who had a history of genital herpes. Ten and 15 specimens, respectively, were positive for herpes simplex virus (HSV)-1 and HSV-2 by cell culture. All of 10 culture-confirmed HSV-1 cases and 11 of 15 (73%) culture-confirmed HSV-2 cases were identified by PCR. Although there were several cases with discrepancy between cell culture and PCR for HSV-2, the results suggest that this PCR procedure could be applied to clinical specimens from the female genital tract.

Restriction enzyme fragment length polymorphisms of amplified herpes simplex virus type-1 DNA provide epidemiologic information

Human herpes simplex type 1 (HSV-1) DNA of isolates from patients in a large teaching hospital was amplified by the polymerase chain reaction (PCR). The PCR products targeted approximately 2100 nt regions of relatively low G + C content. Comparison of restriction enzyme digests of amplified DNA showed variation useful for strain differentiation. Twelve nonrelated HSV-1 were differentiated from one another. In contrast, specimens epidemiologically related in an outbreak were indistinguishable from each other. Restriction endonuclease analysis of amplified HSV-1 sequences appears to be useful for molecular epidemiology and laboratory quality control to detect possible contamination by PCR products.

Laboratory techniques in the diagnosis of herpes simplex infection

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A comparison of enzyme immunoassay and polymerase chain reaction with the clinical examination for diagnosing ocular herpetic disease

PURPOSE

The results of two laboratory diagnostic herpes simplex virus (HSV) tests, an enzyme immunoassay (improved Herpchek [iHC]) and the polymerase chain reaction (PCR), were compared with the clinical examination in the diagnosis of HSV. We determined when diagnostic laboratory tests provided the initial diagnosis of HSV ocular disease and when they were only confirmatory.

METHODS

The sensitivity and specificity of iHC and PCR were determined using 22 HSV culture-positive clinical samples, 10 adenovirus culture-positive clinical samples, 5 samples from normal conjunctivas, 4 bacterial samples, and 1 sample containing Varicella zoster virus. The medical history of the 22 patients with positive HSV cultures were reviewed to determine the initial diagnosis by clinical examination and the initial therapy.

RESULTS

For typical presentations of ocular HSV disease, the clinical examination is as accurate as iHC (P = 0.99) and PCR (P = 0.24). However, for atypical presentations of ocular HSV disease, iHC (P = 0.000005) or PCR (P = 0.00006) were more accurate in detecting HSV infection than the clinical examination.

CONCLUSION

Laboratory diagnosis of HSV from ocular samples was most useful to the clinician in atypical presentations of herpetic ocular disease.

Polymerase chain reaction for detection of herpesvirus simiae (B virus) in clinical specimens

A polymerase chain reaction (PCR) was designed which is specific to Macaca fascicularis (cynomolgus monkey) isolates of B virus. The PCR primers produced the expected 188 basepair product from the Cyno 2 strain and seven other cynomolgus monkey isolates of B virus. Oligomer hybridization with a 31-mer oligonucleotide was used to confirm the origin of this product. The PCR failed to amplify DNA of Epstein-Barr virus, cytomegalovirus, varicella-zoster virus, and other alphaherpesviruses (herpes simplex virus types 1 and 2, four SA 8 isolates and three rhesus isolates of B virus). PCR testing of swabs obtained from four orally-infected cynomolgus monkeys confirmed the presence of B virus DNA in samples previously shown to be positive by culture. In addition, PCR detected B virus in several swabs from infected monkeys that were culture negative. Total DNA extracts from the trigeminal and sacral ganglia of these animals were tested by nested PCR and B virus DNA was detected in the trigeminal ganglia of 3 of the 4 orally-infected cynomolgus monkeys. Nested PCR did not detect B virus DNA in total DNA extracts obtained from the brains of the four monkeys.

DNA and RNA amplification in urology: the polymerase chain reaction

Polymerase chain reaction (PCR) technology is a promising molecular approach for diagnosis of genitourinary tract infections, inherited disorders, tumor-associated genetic alterations and tumor markers. Because it is based on exponential amplification, the technology is capable of ultimate theoretical sensitivity. Although not entirely free of technical limitations, PCR holds advantages over other diagnostic tests, including exquisite sensitivity, specificity, interchangeability and speed.

Detection of latent herpes simplex virus DNA and RNA in human geniculate ganglia by the polymerase chain reaction

By using the polymerase chain reaction (PCR) we detected latent herpes simplex virus type 1 (HSV-1) in human geniculate and trigeminal ganglia obtained from autopsy cases. A pair of primers which were specific for a part of the HSV-1 thymidine kinase domain were used for detection of HSV DNA. We also examined the latency-associated transcript (LAT), known as latency-specific RNA, by means of reverse transcription-PCR with a pair of LAT-specific primers. HSV-1 DNA was detected in 16 of 17 (94%) trigeminal ganglia and in 15 to 17 (88%) geniculate ganglia of adults. We also demonstrated HSV-1 RNA derived from the LAT in both types of ganglia. These findings suggest that HSV-1 latently infects the majority of geniculate and trigeminal ganglia of adults, and that PCR and reverse transcription-PCR are useful tools for analysis of HSV latency.

Underdiagnosis of genital herpes by current clinical and viral-isolation procedures

BACKGROUND

The current clinical strategy for diagnosing genital herpes simplex virus (HSV) infection in women relies on clinical findings plus the selective use of viral culture. The effectiveness of this approach for identifying women with genital herpes is unknown.

METHODS

We performed physical examinations, colposcopy, Pap smears, viral cultures, and HSV type-specific serologic assays of 779 randomly selected women attending a sexually transmitted disease clinic.

RESULTS

Evidence of HSV type 2 infection was detected in 363 women (47 percent), and 9 others (1 percent) had positive cultures indicative of urogenital or anal infection with HSV type 1. Of these 372 women, only 82 (22 percent) had symptoms. Fourteen women (4 percent) had viral shedding without symptoms, 60 (16 percent) had formerly had symptomatic episodes, and 216 (58 percent) had antibodies to HSV-2 with neither viral shedding nor a history of clinical episodes. Characteristic ulcerations of the external genitalia were present in only two thirds of the 66 women with positive HSV cultures; the others had atypical genital lesions or asymptomatic viral shedding. Isolation of HSV from a genitourinary tract specimen was the most sensitive (77 percent) test for confirming a first episode of infection. The detection of HSV-2-specific antibodies was the most sensitive (97 percent) way to confirm symptomatic reactivations of HSV-2 infection. HSV-2 serologic testing also identified the 290 women with asymptomatic HSV-2 infections (37 percent), including 14 (5 percent) who were shedding virus asymptomatically on the day of the examination.

CONCLUSIONS

The current strategy for diagnosing genital HSV infection in women misses many cases. Newly developed type-specific serologic methods can identify women with recurrent genital HSV-2 infection, as well as those with unrecognized or subclinical infection.

Identification of women at unsuspected risk of primary infection with herpes simplex virus type 2 during pregnancy

BACKGROUND

Primary infections with herpes simplex virus type 2 (HSV-2) acquired by women during pregnancy account for about half of the morbidity and mortality from HSV-2 among neonates. The other half results from reactivation of old infections. Better methods are needed to identify which women are at risk for primary HSV-2 infection.

METHODS

We prospectively studied HSV-2 infections among pregnant women who were patients in private obstetrical practices. Using an enzyme-linked immunosorbent assay that detects type-specific antibodies to HSV-2 glycoprotein G, we determined the prevalence at base line of HSV-2 infections among pregnant women and their husbands, the frequency of discordance for infection between partners, and the risk of seroconversion during pregnancy among the seronegative women whose husbands were seropositive.

RESULTS

The seroprevalence of HSV-2 was 32 percent among the 277 women followed throughout their pregnancies and 25 percent among the 190 husbands studied. Two thirds of the HSV-2-seropositive women had no history of genital herpes. Of the 190 couples, 139 (73 percent) were serologically concordant for HSV-2 antibodies (57 percent being seronegative and 16 percent being seropositive), whereas 51 couples (27 percent) were discordant, despite having been sexually intimate for a mean of 6.1 years. Eighteen women who were seronegative for HSV-2 (9.5 percent) had seropositive partners, of whom 10 (56 percent) had no history of genital herpes. Thus, approximately 5 percent of these pregnant women had an unsuspected risk of contracting a primary HSV-2 infection. One of the 18 seronegative women with a seropositive husband seroconverted to HSV-2 during pregnancy; none of the other women seroconverted.

CONCLUSIONS

In this study about 10 percent of pregnant women were at risk of contracting a primary HSV-2 infection from their HSV-2-seropositive husbands. In addition, about a third of these women were seropositive for HSV-2 and thus at risk for asymptomatic, reactivated infections. Serologic testing of couples can identify women who are at risk for primary or reactivated HSV-2 infections during pregnancy.

Development of a polymerase chain reaction-based diagnosis of Trichomonas vaginalis

We developed a polymerase chain reaction (PCR)-based test for detecting the protozoan parasite Trichomonas vaginalis. Genomic libraries were constructed from two independent clinical isolates of T. vaginalis. From these libraries, 12 genomic clones were purified, sequenced, and then screened for uniqueness by computer-assisted sequence comparisons. PCR reactions were performed to evaluate eight PCR-primer pairs, including a primer pair that targeted the T. vaginalis ferredoxin gene. All eight primer pairs yielded PCR products of the expected sizes. However, six of the primer pairs amplified their respective target sequences in limited numbers of clinical T. vaginalis isolates, suggesting the presence of significant genomic variability among isolates. An exception was a primer pair, termed TVA5-TVA6, that amplified a 102-bp genomic sequence, termed A6p, in all of 24 clinical isolates. The A6p sequence was not detected by PCR in human DNA or in a wide variety of flagellates, ciliates, or bacteria tested. The A6p sequence appears highly selective for a broad range of T. vaginalis isolates and holds promise for PCR-based diagnosis of the parasite.

Herpes simplex virus infections of the central nervous system. Encephalitis and neonatal herpes

Herpes simplex virus (HSV) infections are among the most commonly encountered in humans. Fortunately, the resulting diseases are more usually nuisances, such as recurrent fever blisters, rather than life threatening or morbidity inducing. Nevertheless, HSV can result in disease of the central nervous system (CNS) with attendant neurological complications. Examples of the latter include herpes simplex encephalitis (HSE) or neonatal HSV infection. The past decade has witnessed significant advances in our understanding of the pathogenesis of these 2 forms of disease and, even more importantly, their amenability to treatment. This review summarises our current understanding of the natural history, pathogenesis, presentation, and treatment of HSV infections of the CNS. Because of the life-threatening nature of herpes simplex infections of the CNS, particular attention is paid to clinical presentation and differential diagnosis of confounding entities which mimic herpes simplex encephalitis. The controversy of brain biopsy versus alternative noninvasive diagnostic procedures is discussed. Clinical presentation and, importantly, the lack of uniform clinical presentation, as well as the value of intervention with appropriate antiviral drugs such as aciclovir and vidarabine (adenine arabinoside, ara-A), are stressed. The clinical outcome of herpes simplex virus infections of the CNS with therapy is particularly relevant. In spite of early intervention with selective and specific inhibitors of viral replication, return to normal function is not always achieved. At the conclusion of this review, the reader should be aware of the potential value of therapy as well as the problems encountered with diagnosis and management of patients with herpes simplex virus infections of the CNS.

Use of polymerase chain reaction and rabbit infectivity testing to detect Treponema pallidum in amniotic fluid, fetal and neonatal sera, and cerebrospinal fluid

The diagnosis of congenital syphilis continues to pose a difficult clinical challenge. Because the serodiagnosis of congenital syphilis has significant limitations, the direct detection of Treponema pallidum in suspect neonatal tissues or body fluids represents a desirable alternate diagnostic strategy. We developed and applied the polymerase chain reaction (PCR) for the detection of T. pallidum in clinical material relevant to the diagnosis of congenital syphilis but which typically contain factors inhibitory for the PCR. Four methods of specimen processing were examined to circumvent PCR inhibition; clinical materials included amniotic fluids, neonatal sera, and neonatal cerebrospinal fluids. The PCR was 100% specific for T. T. pallidum compared with the sensitive rabbit infectivity test (RIT) for all clinical materials tested. For amniotic fluids, the PCR was 100% sensitive when correlated with the RIT but had a lesser sensitivity when applied to sera or cerebrospinal fluids, which typically contain few treponemes. The combined sensitivity of the PCR for all clinical samples was 78%. Positive PCR results also were obtained among some clinical specimens for which RIT was not performed; these results correlated well with either stigmata or risk factors for congenital syphilis. The combined results suggest that the PCR can be a useful adjunct to the diagnosis and clinical management of congenital syphilis and that it will provide a valuable tool for investigations of the pathogenesis of the disorder.