Neonatal herpes simplex virus infections

Disseminated herpes simplex virus infection in pregnancy

Herpes simplex virus (HSV) types 1 and 2 produce the most common sexually transmitted infection in women, with a higher incidence reported in developing countries. When the first infection occurs during the perinatal period, it can spread, resulting in high morbidity and mortality of the mother and child, in addition to mainly neurological sequelae in the newborn. Despite having reliable laboratory tests, the diagnosis of herpes simplex virus infection in this population is complex since the clinical presentation ranges from asymptomatic or with non-specific symptoms without lesions on the skin or mucous membranes. For this reason, a high clinical suspicion is necessary. Here, we present the case of a mother with disseminated herpes simplex virus type 2 infection with viral hepatitis and fetal death, highlighting the importance of suspecting the diagnosis in febrile women with systemic compromise during the perinatal period, even in the absence of rash.

Sepsis and multi-organ failure due to genital herpes in a healthy person

Herpes simplex virus type 2 (HSV-2) is highly prevalent in several regions of the world and is the main pathogen causing genital herpes, which is transmitted almost exclusively through sexual contact. Systemically disseminated infections caused by HSV-2 are rare and most often seen in newborns, pregnant women, or immunocompromised populations. The virus can invade multiple organs and cause damage. In this paper, we present an extremely rare case of an immunocompetent 36-year-old male who came to our hospital with a high fever with abdominal pain and died of sepsis and multiple organ dysfunction syndrome within a short period. After the exclusion of common pathogens such as bacterial and fungal infections during hospitalization, metagenomic next generation sequencing of the patient's peripheral blood and ascites gave us the answer, and very high nucleic acid sequence counts of HSV-2 were detected in both his peripheral blood and ascites, confirming HSV-2 as the causative virus. In addition, this paper provides a brief review of the relevant literature.

The Many Faces of Neurological Neonatal Herpes Simplex Virus Infection

This case series explores the various manifestations of central nervous system (CNS) involvement in neonatal herpes simplex virus (HSV) infection and highlights the challenges involved in their diagnosis and treatment. Neonatal HSV infection is a rare but serious condition that can have significant neurological consequences. The article presents three cases of neonatal HSV infection, all involving the CNS, each characterized by distinct clinical features and outcomes. Case 1 describes a three-week-old male with severe HSV meningoencephalitis resulting in poor response to treatment and death. Cases 2 and 3 describe younger neonates who presented early in the disease course with disseminated infection and skin, eye, and mouth (SEM) lesions. Although both patients had CNS involvement, their outcomes were remarkably favorable. The wide range of clinical presentations of CNS manifestations in neonatal HSV infection, ranging from nonspecific to evident neurological symptoms, underscores the need for a high index of suspicion and comprehensive evaluation to ensure early diagnosis and appropriate treatment. However, it also notes that even with timely treatment, some cases may still have a poor prognosis.

Exposure-safety relationship for acyclovir in the treatment of neonatal herpes simplex virus disease

BACKGROUND

Neonatal herpes simplex virus (HSV) disease has been treated with high-dose (20 mg/kg/dose) acyclovir since 1991.

AIMS

Determine the safety of acyclovir in infants with neonatal HSV treated with high-dose acyclovir; examine the association between acyclovir dose and exposure with adverse events (AEs).

STUDY DESIGN

We obtained demographic information and acyclovir dosing via medical records. Acyclovir exposure was calculated using an established pharmacokinetic model.

SUBJECTS

Infants <120 days of age with neonatal HSV discharged from four academic children's hospitals.

OUTCOME MEASURES

We identified clinical and laboratory adverse events (AEs).

RESULTS AND CONCLUSIONS

We identified 49 infants with neonatal HSV treated with acyclovir; 42 infants had complete 21-day dosing information. Median mean daily dose was 59 mg/kg/day. Clinical AEs were common among all gestational and postnatal age groups. Rash was the most common clinical AE (37 %). Mild laboratory AEs occurred in 2-37 % of infants. The median maximum doses (mg/kg/day) were higher among infants with hypokalemia, elevated blood urea nitrogen, and thrombocytosis. For all other laboratory AEs, the median maximum doses for infants without events were higher or equal to the median maximum dose of infants with the AE. The odds of experiencing any clinical or laboratory AE did not differ by predicted acyclovir exposure for either area under the curve (AUC) or maximum concentration (Cmax) (odds ratio [OR] = 1.00 [0.98, 1.03] and OR = 1.01 [0.93, 1.12], respectively). Although AEs were common with high-dose acyclovir exposure, severe AEs were rare. Acyclovir exposure was not associated with AEs.

Infections and Pregnancy: Effects on Maternal and Child Health

Pregnancy causes physiological and immunological adaptations that allow the mother and fetus to communicate with precision in order to promote a healthy pregnancy. At the same time, these adaptations may make pregnant women more susceptible to infections, resulting in a variety of pregnancy complications; those pathogens may also be vertically transmitted to the fetus, resulting in adverse pregnancy outcomes. Even though the placenta has developed a robust microbial defense to restrict vertical microbial transmission, certain microbial pathogens have evolved mechanisms to avoid the placental barrier and cause congenital diseases. Recent mechanistic studies have begun to uncover the striking role of the maternal microbiota in pregnancy outcomes. In this review, we discuss how microbial pathogens overcome the placental barrier to cause congenital diseases. A better understanding of the placental control of fetal infection should provide new insights into future translational research.

Heterogeneous cutaneous findings associated with intrauterine HSV infection: A case series and literature review

BACKGROUND/OBJECTIVE

Herpes simplex virus (HSV) infection acquired in utero may present with non-vesicular dermatologic findings in affected newborns, which may pose a diagnostic dilemma. We aimed to describe and assess the range of non-vesiculobullous skin lesions that neonates with intrauterine HSV infection may manifest at birth.

METHODS

We collected a multicenter case series and conducted a literature review of neonates with intrauterine HSV infection presenting with non-vesiculobullous cutaneous lesions.

RESULTS

Twenty-two cases were reviewed, including six managed clinically by members of our team and 16 identified in the literature. Four (18%) were associated with twin pregnancies, and thirteen (59%) cases occurred in premature infants. Only four (18%) mothers had a documented history of HSV infection. Twelve (55%) cases resulted in poor outcomes, including long-term neurologic sequelae or death. Cutaneous manifestations included erosions, ulcerations, crusted papules or plaques, calcinosis cutis, excoriations, macules (erythematous, hypopigmented, or hyperpigmented), cutaneous atrophy, contractures, and bruising. About one-third of neonates developed new-onset vesicular lesions within a week of birth; in each of these cases, accurate diagnosis and therapy were delayed until appearance of vesicles.

CONCLUSIONS

The range of dermatologic findings associated with intrauterine HSV is extremely broad, and the various morphologies present at birth likely reflect different stages of the ongoing evolution of an HSV infection that began in utero. Clinicians should have a low threshold for HSV testing in premature neonates born with atypical cutaneous lesions, since early detection and treatment of HSV may reduce morbidity and mortality from systemic complications.

Neonatal Herpes Simplex Virus Disease: Updates and Continued Challenges

This article defines neonatal herpes simplex virus (HSV) disease and describes the progress over the past 40 years that has revolutionized the management of HSV disease in neonates to improve their outcomes. These advancements include the introduction of acyclovir in the 1980s, polymerase chain reaction (PCR) for the detection of HSV DNA in the 1990s, and recommendations on managing infants born to mothers with active genital lesions. Despite these advancements, however, there remain high morbidity and mortality in affected neonates, with need for continued improvement. Areas of high interest include vaccine development and rapid PCR detection at time of delivery.

High Preventive Effect of G2-S16 Anionic Carbosilane Dendrimer against Sexually Transmitted HSV-2 Infection

Anionic carbosilane dendrimers such as G2-S16 are very effective in preventing HSV-2 infection both in vitro and in vivo. We present the main achievements obtained for the G2-S16 dendrimer in vivo, especially related to its efficacy against HSV-2 infection. Moreover, we discuss the mechanisms by which the G2-S16 dendrimer applied vaginally as a topical microbicide has been demonstrated to be safe and harmless for the vaginal microbiome balance, as both conditions present an essential step that has to be overcome during microbicide development. This review points to the marked protective effect of the G2-S16 dendrimer against sexually transmitted HSV-2 infection, supporting its role as a possible microbicide against HSV-2 infection.

Evaluation for Neonatal HSV in Infants Undergoing Workup for Serious Bacterial Infection: A 5-Year Retrospective Review

OBJECTIVES

To describe the characteristics of infants evaluated for serious bacterial infection, focusing on empirical testing and treatment of herpes simplex virus (HSV) and describe the characteristics of HSV-positive patients.

METHODS

We included infants aged 0 to 60 days undergoing evaluation for serious bacterial infection in the emergency department. This descriptive study was conducted between July 2010 and June 2014 at a tertiary-care children's hospital. Eligible patients were identified on the basis of age at presentation to the hospital and laboratory specimens. Infant characteristics, symptoms on presentation, and laboratory workup were compared between HSV-positive and HSV-negative patients by using the 2-sample t test or the Wilcoxon rank test.

RESULTS

A total of 1633 infants were eligible for inclusion, and 934 (57.2%) were 0 to 28 days of age. HSV was diagnosed in 19 infants, 11 of whom had disseminated disease. Compared with those without HSV, HSV-positive infants were younger, less likely to be febrile and to present with nonspecific symptoms, and more likely to have a mother with HSV symptoms (P < .05). Testing from all recommended locations was only performed in 22% of infants. Infants tested or empirically treated with acyclovir had a longer median length of stay compared with children who were not tested or treated (P < .01).

CONCLUSIONS

The absence of fever should not preclude a workup for HSV in neonates, and when a workup is initiated, emphasis should be placed on obtaining samples from serum, cerebrospinal fluid, and surface specimens. Physicians may benefit from a guideline for evaluation of HSV with specific guidance on high-risk features of presentation and recommended testing.

Using Quality Improvement to Implement a Standardized Approach to Neonatal Herpes Simplex Virus

OBJECTIVES

Neonatal herpes simplex virus (HSV) infections are associated with high mortality and long-term morbidity. However, incidence is low and acyclovir, the treatment of choice, carries risk of toxicity. We aimed to increase the percentage of patients 0 to 60 days of age who are tested and treated for HSV in accordance with local guideline recommendations from 40% to 80%.

METHODS

This quality improvement project took place at 1 freestanding children's hospital. Multiple plan-do-study-act cycles were focused on interventions aimed at key drivers including provider buy-in, guideline availability, and accurate identification of high-risk patients. A run chart was used to track the effect of interventions on the percentage managed per guideline recommendations over time by using established rules for determining special cause. Pre- and postimplementation acyclovir use was compared by using a χ² test. In HSV-positive cases, delayed acyclovir initiation, defined as >1 day from presentation, was tracked as a balancing measure.

RESULTS

The median percentage of patients managed according to guideline recommendations increased from 40% to 80% within 8 months. Acyclovir use decreased from 26% to 7.9% (P < .001) in non-high-risk patients but did not change significantly in high-risk patients (73%-83%; P = .15). There were no cases of delayed acyclovir initiation in HSV-positive cases.

CONCLUSIONS

Point-of-care availability of an evidence-based guideline and interventions targeted at provider engagement improved adherence to a new guideline for neonatal HSV management and decreased acyclovir use in non-high-risk infants. Further study is necessary to confirm the safety of these recommendations in other settings.

Epidemiology and Immune Pathogenesis of Viral Sepsis

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. Sepsis can be caused by a broad range of pathogens; however, bacterial infections represent the majority of sepsis cases. Up to 42% of sepsis presentations are culture negative, suggesting a non-bacterial cause. Despite this, diagnosis of viral sepsis remains very rare. Almost any virus can cause sepsis in vulnerable patients (e.g., neonates, infants, and other immunosuppressed groups). The prevalence of viral sepsis is not known, nor is there enough information to make an accurate estimate. The initial standard of care for all cases of sepsis, even those that are subsequently proven to be culture negative, is the immediate use of broad-spectrum antibiotics. In the absence of definite diagnostic criteria for viral sepsis, or at least to exclude bacterial sepsis, this inevitably leads to unnecessary antimicrobial use, with associated consequences for antimicrobial resistance, effects on the host microbiome and excess healthcare costs. It is important to understand non-bacterial causes of sepsis so that inappropriate treatment can be minimised, and appropriate treatments can be developed to improve outcomes. In this review, we summarise what is known about viral sepsis, its most common causes, and how the immune responses to severe viral infections can contribute to sepsis. We also discuss strategies to improve our understanding of viral sepsis, and ways we can integrate this new information into effective treatment.

Herpes Simplex Virus Infection in Infants Undergoing Meningitis Evaluation

BACKGROUND

Although neonatal herpes simplex virus (HSV) is a potentially devastating infection requiring prompt evaluation and treatment, large-scale assessments of the frequency in potentially infected infants have not been performed.

METHODS

We performed a retrospective cross-sectional study of infants ≤60 days old who had cerebrospinal fluid culture testing performed in 1 of 23 participating North American emergency departments. HSV infection was defined by a positive HSV polymerase chain reaction or viral culture. The primary outcome was the proportion of encounters in which HSV infection was identified. Secondary outcomes included frequency of central nervous system (CNS) and disseminated HSV, and HSV testing and treatment patterns.

RESULTS

Of 26 533 eligible encounters, 112 infants had HSV identified (0.42%, 95% confidence interval [CI]: 0.35%-0.51%). Of these, 90 (80.4%) occurred in weeks 1 to 4, 10 (8.9%) in weeks 5 to 6, and 12 (10.7%) in weeks 7 to 9. The median age of HSV-infected infants was 14 days (interquartile range: 9-24 days). HSV infection was more common in 0 to 28-day-old infants compared with 29- to 60-day-old infants (odds ratio 3.9; 95% CI: 2.4-6.2). Sixty-eight (0.26%, 95% CI: 0.21%-0.33%) had CNS or disseminated HSV. The proportion of infants tested for HSV (35%; range 14%-72%) and to whom acyclovir was administered (23%; range 4%-53%) varied widely across sites.

CONCLUSIONS

An HSV infection was uncommon in young infants evaluated for CNS infection, particularly in the second month of life. Evidence-based approaches to the evaluation for HSV in young infants are needed.

Living donor liver transplantation for neonatal fulminant hepatitis due to herpes simplex virus infection

Although rare, ALF caused by disseminated HSV infection is associated with high mortality in the neonatal population. This condition is often diagnosed relatively late due to the absence of specific signs. We present a case involving a neonate with ALF submitted to living donor liver transplantation without a prior diagnosis. The patient had no skin or mucosal lesions, and IgM serology was negative for HSV-1 and HSV-2. Immunohistochemical staining of the liver explant was positive for herpes virus infection, and the patient subsequently received antiviral drug treatment, with a good outcome. Due to organ shortages and the rarity of the aforementioned condition, LT has seldom been reported for the treatment of ALF caused by herpes virus infection; however, LT may be the only option for neonates with fulminant hepatitis. The use of living donors in an urgent scenario is well established in Eastern countries and safely applicable for pediatric patients with ALF.

Clinical Pathway Effectiveness: Febrile Young Infant Clinical Pathway in a Pediatric Emergency Department

OBJECTIVE

Young infants are often treated in emergency departments (EDs) for febrile illnesses. Any delay in care or ineffective management could lead to increased patient morbidity and mortality. A standardized ED clinical pathway may improve care for these patients. The objective of this study is to evaluate the impact of a febrile young infant clinical pathway implemented in a large, urban children's hospital ED on the timeliness and consistency of care.

METHODS

This study used a before-and-after retrospective observational study design comparing 2 separate periods: prepathway from September 2007 through August 2008 and postpathway from September 2009 through August 2010. Subjects were infants aged 56 days or younger presenting with a rectal temperature of 38.0°C or higher. Patients were excluded if they were transferred from another hospital or if they developed a fever after initial presentation.

RESULTS

Five hundred twenty infants were enrolled. The mean time to urine collection and time to the first antibiotic administration were reduced after pathway implementation (23-minute reduction to urine collection vs 36-minute reduction to the first antibiotic administration). There was improvement in the proportion of infants who received the pathway-specific antibiotics based on age (odds ratio, 7.2; 95% confidence interval, 4.4, 11.9) and the proportion of infants who were administered acyclovir based on pathway guidelines (odds ratio, 8.8; 95% confidence interval, 2.9-30.0).

CONCLUSIONS

An ED-based febrile young infant clinical pathway improved the timeliness of initiation of work-up as measured by urine collection and of therapy by an earlier administration of the first antibiotic, as well as decreased variability of care.

Infectious causes of microcephaly: epidemiology, pathogenesis, diagnosis, and management

Microcephaly is an important sign of neurological malformation and a predictor of future disability. The 2015-16 outbreak of Zika virus and congenital Zika infection brought the world's attention to links between Zika infection and microcephaly. However, Zika virus is only one of the infectious causes of microcephaly and, although the contexts in which they occur vary greatly, all are of concern. In this Review, we summarise important aspects of major congenital infections that can cause microcephaly, and describe the epidemiology, transmission, clinical features, pathogenesis, management, and long-term consequences of these infections. We include infections that cause substantial impairment: cytomegalovirus, herpes simplex virus, rubella virus, Toxoplasma gondii, and Zika virus. We highlight potential issues with classification of microcephaly and show how some infants affected by congenital infection might be missed or incorrectly diagnosed. Although Zika virus has brought the attention of the world to the problem of microcephaly, prevention of all infectious causes of microcephaly and appropriately managing its consequences remain important global public health priorities.

Congenital Herpes Simplex Virus Type 1 Infection Mimicking Congenital Erosive and Vesicular Dermatosis: Possible Pathogenic Insights

Congenital erosive and vesicular dermatosis (CEVD) is a rare entity of unknown etiology. We report a case of congenital herpes simplex virus (HSV) type 1 infection that healed with reticulated and supple scarring, similar to that seen in CEVD. Twenty percent of previously reported cases of CEVD had recurrent HSV infection throughout the first year of life. We postulate that at least some previous cases of CEVD may have been due to undiagnosed congenital HSV infection.

Herpes Simplex Virus and Varicella-Zoster Virus

The most common specimens from immunocompromised patients that are analyzed for detection of herpes simplex virus (HSV) or varicella-zoster virus (VZV) are from skin lesions. Many types of assays are applicable to these samples, but some, such as virus isolation and direct fluorescent antibody testing, are useful only in the early phases of the lesions. In contrast, nucleic acid (NA) detection methods, which generally have superior sensitivity and specificity, can be applied to skin lesions at any stage of progression. NA methods are also the best choice, and sometimes the only choice, for detecting HSV or VZV in blood, cerebrospinal fluid, aqueous or vitreous humor, and from mucosal surfaces. NA methods provide the best performance when reliability and speed (within 24 hours) are considered together. They readily distinguish the type of HSV detected or the source of VZV detected (wild type or vaccine strain). Nucleic acid detection methods are constantly being improved with respect to speed and ease of performance. Broader applications are under study, such as the use of quantitative results of viral load for prognosis and to assess the efficacy of antiviral therapy.

Global sensing of the antigenic structure of herpes simplex virus gD using high-throughput array-based SPR imaging

While HSV-2 typically causes genital lesions, HSV-1 is increasingly the cause of genital herpes. In addition, neonatal HSV infections are associated with a high rate of mortality and HSV-2 may increase the risk for HIV or Zika infections, reinforcing the need to develop an effective vaccine. In the GSK Herpevac trial, doubly sero-negative women were vaccinated with a truncated form of gD2 [gD2(284t)], then examined for anti-gD serum titers and clinical manifestations of disease. Surprisingly, few vaccinees were protected against genital HSV-2 but 86% were protected from genital HSV-1. These observations suggest that subtle differences in gD structure might influence a protective response. To better understand the antigenic structure of gD and how it impacts a protective response, we previously utilized several key anti-gD monoclonal antibodies (mAbs) to dissect epitopes in vaccinee sera. Several correlations were observed but the methodology limited the number of sera and mAbs that could be tested. Here, we used array-based surface plasmon imaging (SPRi) to simultaneously measure a larger number of protein-protein interactions. We carried out cross-competition or "epitope binning" studies with 39 anti-gD mAbs and four soluble forms of gD, including a form [gD2(285t)] that resembles the Herpevac antigen. The results from these experiments allowed us to organize the mAbs into four epitope communities. Notably, relationships within and between communities differed depending on the form of gD, and off-rate analysis suggested differences in mAb-gD avidity depending on the gD serotype and length. Together, these results show that gD1 and gD2 differ in their structural topography. Consistent with the Herpevac results, several mAbs that bind both gD1 and gD2 neutralize only HSV-1. Thus, this technology provides new insights into the antigenic structure of gD and provides a rationale as to how vaccination with a gD2 subunit may lead to protection from HSV-1 infection.

Persistent Gaps in Appropriate Use of Empiric Acyclovir in Neonates

The use of empiric acyclovir for suspected neonatal herpes simplex virus (HSV) infection has been debated for years. To identify the gap in the decision to initiate empiric acyclovir, we performed a retrospective chart review and administered a survey to pediatricians to assess current practices regarding evaluation for possible HSV infection. Seventy infants received empiric acyclovir over a 1-year period; of these, 3 infants (4.3%) had positive HSV testing. Fourteen infants were identified as "high-risk" for HSV infection; of these, 13 infants had incomplete testing. Survey results revealed uncertainty in the decision to initiate acyclovir and in the composition of complete diagnostic testing. This study confirmed the clinical uncertainty in the decision to initiate empiric acyclovir. Using this chart review and survey as a baseline, future efforts will focus on a quality improvement project to reduce empiric acyclovir use in low-risk infants and to ensure complete diagnostic evaluation in high-risk infants.

The herpevac trial for women: Sequence analysis of glycoproteins from viruses obtained from infected subjects

The Herpevac Trial for Women revealed that three dose HSV-2 gD vaccine was 58% protective against culture-positive HSV-1 genital disease, but it was not protective against HSV-2 infection or disease. To determine whether vaccine-induced immune responses had selected for a particular gD sequence in strains infecting vaccine recipients compared with viruses infecting control subjects, genetic sequencing studies were carried out on viruses isolated from subjects infected with HSV-1 or HSV-2. We identified naturally occurring variants among the gD sequences obtained from 83 infected subjects. Unique or low frequency amino acid substitutions in the ectodomain of gD were found in 6 of 39 HSV-1-infected subjects and in 7 of 44 HSV-2-infected subjects. However, no consistent amino acid change was identified in isolates from gD-2 vaccine recipients compared with infected placebo recipients. gC and gE surround and partially shield gD from neutralizing antibody, and gB also participates closely in the viral entry process. Therefore, these genes were sequenced from a number of isolates to assess whether sequence variation may alter protein conformation and influence the virus strain’s capacity to be neutralized by vaccine-induced antibody. gC and gE genes sequenced from HSV-1-infected subjects showed more variability than their HSV-2 counterparts. The gB sequences of HSV-1 oral isolates resembled each other more than they did gB sequences rom genital isolates. Overall, however, comparison of glycoprotein sequences of viral isolates obtained from infected subjects did not reveal any singular selective pressure on the viral cell attachment protein or surrounding glycoproteins due to administration of gD-2 vaccine.

Safety of High-dose Acyclovir in Infants With Suspected and Confirmed Neonatal Herpes Simplex Virus Infections

BACKGROUND

Acyclovir is used to treat herpes simplex virus disease in infants. Treatment with high-dose acyclovir, 60 mg/kg/d, is recommended; however, the safety of this dosage has not been assessed in the past 15 years, and this dosage is not currently approved for infants by the US Food and Drug Administration.

METHODS

We included infants with neonatal herpes simplex virus disease treated with ≥14 days of intravenous acyclovir starting in the first 120 days of life admitted to 1 of 42 neonatal intensive care units managed by the Pediatrix Medical Group between 2002 and 2012. We determined the frequency and proportion of infants with clinical and laboratory adverse events (AEs) as well as the number and proportion of infant days with laboratory AEs occurring during acyclovir exposure.

RESULTS

We identified 89 infants during the study period with 1658 days of acyclovir exposure. Almost all received high-dose acyclovir therapy (79/89, 89%). The most common clinical AEs were hypotension and seizure, both occurring in 9% of infants. Thrombocytopenia was the most common laboratory AE occurring in 25% of infants and on 9% of infant-days. Elevated creatinine occurred in 2% of infants and 0.2% of infant-days and no infants developed renal failure requiring dialysis. Overall, 45% of infants had ≥1 AE.

CONCLUSIONS

In this cohort of infants treated during the high-dose acyclovir era, AEs were common but usually not severe. Many of the AEs reported in this cohort may be related to the underlying infection rather than due to acyclovir exposure.

Herpes simplex keratitis: challenges in diagnosis and clinical management

Herpes simplex virus is responsible for numerous ocular diseases, the most common of which is herpetic stromal keratitis. This is a recurrent infection of the cornea that typically begins with a subclinical infection of the cornea that establishes a latent infection of sensory ganglia, most often the trigeminal ganglia. Recurring infections occur when the virus is reactivated from latency and travels back to the cornea, where it restimulates an inflammatory response. This inflammatory response can lead to decreased corneal sensation, scarring, and blindness. The diagnosis of these lesions as the result of a recurrent herpes simplex virus infection can at times be problematic. Currently, herpetic stromal keratitis is diagnosed by its clinical presentation on the slit-lamp examination, but the literature does not always support the accuracy of these clinical findings. Other diagnostic tests such as polymerase chain reaction assay, enzyme-linked immunosorbent assay, immunofluorescent antibody, and viral cultures have provided more definitive diagnosis, but also have some limitations. That said, accurate diagnosis is necessary for proper treatment, in order to prevent serious consequences. Current treatment reduces the severity of lesions and controls further viral spread, but does not provide a cure.

Infant Deaths Due To Herpes Simplex Virus, Congenital Syphilis, and HIV in New York City

BACKGROUND

Neonatal infection with herpes simplex virus (HSV) is not a nationally reportable disease; there have been few population-based measures of HSV-related infant mortality. We describe infant death rates due to neonatal HSV as compared with congenital syphilis (CS) and HIV, 2 reportable, perinatally transmitted diseases, in New York City from 1981 to 2013.

METHODS

We identified neonatal HSV-, CS-, and HIV-related deaths using International Classification of Diseases (ICD) codes listed on certificates of death or stillbirth issued in New York City. Deaths were classified as HSV-related if certificates listed (1) any HSV ICD-9/ICD-10 codes for deaths ≤42 days of age, (2) any HSV ICD-9/ICD-10 codes and an ICD code for perinatal infection for deaths at 43 to 365 days of age, or (3) an ICD-10 code for congenital HSV. CS- and HIV-related deaths were those listing any ICD code for syphilis or HIV.

RESULTS

There were 34 deaths due to neonatal HSV (0.82 deaths per 100 000 live births), 38 from CS (0.92 per 100 000), and 262 from HIV (6.33 per 100 000). There were no CS-related deaths after 1996, and only 1 HIV-related infant death after 2004. The neonatal HSV-related death rate during the most recent decade (2004-2013) was significantly higher than in previous years.

CONCLUSIONS

The increasing neonatal HSV-related death rate may reflect increases in neonatal herpes incidence; an increasing number of pregnant women have never had HSV type 1 and are therefore at risk of acquiring infection during pregnancy and transmitting to their infant.

HSV targeting of the host phosphatase PP1α is required for disseminated disease in the neonate and contributes to pathogenesis in the brain

Newborns are significantly more susceptible to severe disease after infection with herpes simplex virus (HSV) compared with adults, with differences in the host response implicated as a major factor. To understand host response differences between these age groups, we investigated the shutoff of protein synthesis by the host and the retargeting of host phosphatase PP1α by the HSV-1 protein γ34.5 for reversal of translational arrest. In a murine newborn model of viral dissemination, infection with the HSV-1 mutant for PP1α binding resulted in complete absence of disease. PP1α-binding mutant HSV-1 replicated in visceral organs early after inoculation, demonstrating that HSV-1 replication requires PP1α-targeting only later in infection. Newborn mice deficient in type I IFN signaling partially rescued the virulence of the PP1α-binding mutant virus, suggesting an IFN-independent role for eIF2α kinases during infection. When we investigated the contribution of PP1α targeting to pathogenesis in the brain, we found that the inability of HSV-1 to bind PP1α increased survival time in both newborn and adult mice. Unlike disseminated disease, type I IFN signaling in the brain was required to attenuate disease following PP1α-mutant virus infection. Furthermore, pharmacologic inhibition of eIF2α dephosphorylation reduced HSV-1 replication in a brain slice culture model of encephalitis. Our findings reveal age-dependent differences in γ34.5 function and tissue-specific reliance on the type I IFN response for protection from HSV disease. These results define an important role for γ34.5 in neonatal infections in contrast to other studies indicating that the autophagy-inhibiting function of γ34.5 is dispensable for pathogenesis in the newborn brain.

Pharmacokinetic considerations in the use of antivirals in neonates

INTRODUCTION

Neonatal patients, because of the inability of their immune system to properly respond to microbial challenge, are highly susceptible to viral infections. Immunoglobulins, monoclonal antibody and antiviral drugs are used for prophylaxis and treatment of viral diseases in neonates. Neonates and, especially, preterm infants differ in drug absorption, distribution, metabolism and excretion from adults and older children.

AREAS COVERED

This review will evaluate deficiencies of neonatal immune responses to microbial challenge that predispose newborns to viral infections, clinical manifestations and the treatment of viral diseases in neonates. We focus on published studies describing antiviral drug pharmacokinetics in neonates and make recommendations on the dosing of these drugs, allowing achievement of maximal clinical benefits in neonates.

EXPERT OPINION

While some efforts were undertaken to study pharmacokinetics and pharmacodynamics of antiviral drugs, much more needs to be done. Current data indicate that the pharmacokinetics of antiviral drugs may vary significantly depending on gestational age, maturation processes of drug-metabolizing enzymes and renal clearance. Specifics of pharmacokinetics of antiviral drugs need to be taken into consideration when they are prescribed to neonates and infants.

Molecular diagnostics and newborns at risk for genital herpes simplex virus

Herpes simplex virus (HSV) infection in the newborn carries a high mortality rate and can result in lifelong neurologic impairment. The severity of HSV infection in the newborn has always dictated conservative management when prodromal symptoms or active genital lesions (or those suggestive of genital herpes) are present during labor and delivery. The risk of intrapartum infection, however, is related to the presence or absence of maternal immunity (neutralizing antibody) to HSV. The most significant risk of transmission is in first-episode primary infections with active lesions at delivery. Recent recommendations from the American Academy of Pediatrics Committees on Infectious Diseases and the Fetus and Newborn use rapid serologic and virologic screening in the management of asymptomatic infants born to mothers with active genital herpes. The revised guidelines highlight infants at greatest risk for HSV disease but do not apply to asymptomatic infants born to mothers with a history of HSV but no genital lesions at delivery. The current guidelines also stipulate that maternal serologic screening and molecular assays for HSV in newborn blood and cerebrospinal fluid must be available and reported in a timely fashion.

Herpes Simplex Virus DNAemia Preceding Neonatal Disease

Polymerase chain reaction testing of blood for herpes simplex virus (HSV) is recommended for newborns delivered to mothers with active genital HSV lesions at delivery. We report an infant who had a positive blood HSV polymerase chain reaction test before the onset of clinical signs of HSV disease.

Differential reliance on autophagy for protection from HSV encephalitis between newborns and adults

Newborns are more susceptible to severe disease from infection than adults, with maturation of immune responses implicated as a major factor. The type I interferon response delays mortality and limits viral replication in adult mice in a model of herpes simplex virus (HSV) encephalitis. We found that intact type I interferon signaling did not control HSV disease in the neonatal brain. However, the multifunctional HSV protein γ34.5 involved in countering type I interferon responses was important for virulence in the brain in both age groups. To investigate this observation further, we studied a specific function of γ34.5 which contributes to HSV pathogenesis in the adult brain, inhibition of the cellular process of autophagy. Surprisingly, we found that the beclin binding domain of γ34.5 responsible for inhibiting autophagy was dispensable for HSV disease in the neonatal brain, as infection of newborns with the deletion mutant decreased time to mortality compared to the rescue virus. Additionally, a functional beclin binding domain in HSV γ34.5 did not effectively inhibit autophagy in the neonate, unlike in the adult. Type I IFN responses promote autophagy in adult, a finding we confirmed in the adult brain after HSV infection; however, in the newborn brain we observed that autophagy was activated through a type I IFN-independent mechanism. Furthermore, autophagy in the wild-type neonatal mouse was associated with increased apoptosis in infected regions of the brain. Observations in the mouse model were consistent with those in a human case of neonatal HSV encephalitis. Our findings reveal age-dependent differences in autophagy for protection from HSV encephalitis, indicating developmental differences in induction and regulation of this innate defense mechanism after HSV infection in the neonatal brain.

Disease after infection with a pathogen results from an intersection between the infectious agent and the host. Newborns are particularly susceptible to infectious illness compared to adults, and HSV infection commonly results in devastating encephalitis. We studied the interaction of HSV with the type I interferon pathway and found that a specific activity of the viral protein γ34.5, which counters host autophagy to promote encephalitis in adults, was not required to cause disease in newborns. Furthermore, autophagy was not inhibited by HSV in the neonate and was not activated by type I interferon signaling, unlike in the adult. Activated autophagy was associated with increased apoptosis, which may contribute to the increased pathology in newborns. Our findings reveal development-specific differences in the pathogenesis of HSV encephalitis, including a distinct role for autophagy in the neonatal brain.

Antigenic breadth: a missing ingredient in HSV-2 subunit vaccines?

The successful human papillomavirus and hepatitis B virus subunit vaccines contain single viral proteins that represent 22 and 12%, respectively, of the antigens encoded by these tiny viruses. The herpes simplex virus 2 (HSV-2) genome is >20 times larger. Thus, a single protein subunit represents 1% of HSV-2's total antigenic breadth. Antigenic breadth may explain why HSV-2 glycoprotein subunit vaccines have failed in clinical trials, and why live HSV-2 vaccines that express 99% of HSV-2's proteome may be more effective. I review the mounting evidence that live HSV-2 vaccines offer a greater opportunity to stop the spread of genital herpes, and I consider the unfounded 'safety concerns' that have kept live HSV-2 vaccines out of U.S. clinical trials for 25 years.

A flexible and low-cost polypropylene pouch for naked-eye detection of herpes simplex viruses

Effective viral detection is a key goal in the development of point of care (POC) diagnostic devices.

Herpes simplex virus infection during pregnancy

Genital herpes in pregnancy continues to cause significant maternal morbidity, with an increasing number of infections being due to oral-labial transmission of herpes simplex virus (HSV)-1. Near delivery, primary infections with HSV-1 or HSV-2 carry the highest risk of neonatal herpes infection, which is a rare but potentially devastating disease for otherwise healthy newborns. Prevention efforts have been limited by lack of an effective intervention for preventing primary infections and the unclear role of routine serologic testing.

Early-onset neonatal sepsis

Early-onset sepsis remains a common and serious problem for neonates, especially preterm infants. Group B streptococcus (GBS) is the most common etiologic agent, while Escherichia coli is the most common cause of mortality. Current efforts toward maternal intrapartum antimicrobial prophylaxis have significantly reduced the rates of GBS disease but have been associated with increased rates of Gram-negative infections, especially among very-low-birth-weight infants. The diagnosis of neonatal sepsis is based on a combination of clinical presentation; the use of nonspecific markers, including C-reactive protein and procalcitonin (where available); blood cultures; and the use of molecular methods, including PCR. Cytokines, including interleukin 6 (IL-6), interleukin 8 (IL-8), gamma interferon (IFN-γ), and tumor necrosis factor alpha (TNF-α), and cell surface antigens, including soluble intercellular adhesion molecule (sICAM) and CD64, are also being increasingly examined for use as nonspecific screening measures for neonatal sepsis. Viruses, in particular enteroviruses, parechoviruses, and herpes simplex virus (HSV), should be considered in the differential diagnosis. Empirical treatment should be based on local patterns of antimicrobial resistance but typically consists of the use of ampicillin and gentamicin, or ampicillin and cefotaxime if meningitis is suspected, until the etiologic agent has been identified. Current research is focused primarily on development of vaccines against GBS.

Repertoire of epitopes recognized by serum IgG from humans vaccinated with herpes simplex virus 2 glycoprotein D

The results of a clinical trial of a subunit vaccine against genital herpes were recently reported (R. B. Belshe, P. A. Leone, D. I. Bernstein, A. Wald, M. J. Levin, J. T. Stapleton, I. Gorfinkel, R. L. Morrow, M. G. Ewell, A. Stokes-Riner, G. Dubin, T. C. Heineman, J. M. Schulte, C. D. Deal, N. Engl. J. Med. 366: 34-43, 2012, doi:10.1056/NEJMoa1103151). The vaccine consisted of a soluble form of herpes simplex virus 2 (HSV-2) glycoprotein D (gD2) with adjuvant. The goal of the current study was to examine the composition of the humoral response to gD2 within a selected subset of vaccinated individuals. Serum samples from 30 vaccine recipients were selected based upon relative enzyme-linked immunosorbent assay (ELISA) titers against gD2; 10 samples had high titers, 10 had medium titers, and the remaining 10 had low ELISA titers. We employed a novel, biosensor-based monoclonal antibody (MAb)-blocking assay to determine whether gD2 vaccination elicited IgG responses against epitopes overlapping those of well-characterized MAbs. Importantly, IgGs from the majority of gD2-immunized subjects competed for gD binding with four antigenically distinct virus-neutralizing MAbs (MC2, MC5, MC23, and DL11). Screening of patient IgGs against overlapping peptides spanning the gD2 ectodomain revealed that about half of the samples contained antibodies against linear epitopes within the N and C termini of gD2. We found that the virus-neutralizing abilities of the 10 most potent samples correlated with overall gD-binding activity and to an even greater extent with the combined content of IgGs against the epitopes of MAbs MC2, MC5, MC23, and DL11. This suggests that optimal virus-neutralizing activity is achieved by strong and balanced responses to the four major discontinuous neutralizing epitopes of gD2. Importance: Several herpes simplex virus 2 (HSV-2) subunit vaccine studies have been conducted in human subjects using a recombinant form of HSV-2 glycoprotein D (gD2). Although several distinct, well-characterized virus-neutralizing epitopes on gD2 are targeted by murine monoclonal antibodies, it is not known whether the same epitopes are targeted by the humoral response to gD2 in humans. We have developed a novel, biosensor-based competition assay to directly address this important question. Using this approach, we identified epitopes that elicit strong humoral responses in humans, as well as other epitopes that elicit much weaker responses. These data provide new insight into the human response to known neutralizing gD2 epitopes and reveal characteristics of this response that may guide future vaccine development.

Neonatal herpes simplex virus type-1 central nervous system disease with acute retinal necrosis

We report a case of neonatal herpes simplex virus (HSV)-1 central nervous system disease with bilateral acute retinal necrosis (ARN). An infant was presented at 17 days of age with focal seizures. Cerebrospinal fluid polymerase chain reaction was positive for HSV-1 and brain magnetic resonance imaging showed cerebritis. While receiving intravenous acyclovir therapy, the infant developed ARN with vitreous fluid polymerase chain reaction positive for HSV-1 necessitating intravitreal foscarnet therapy. This is the first reported neonatal ARN secondary to HSV-1 and the first ARN case presenting without external ocular or cutaneous signs. Our report highlights that infants with neonatal HSV central nervous system disease should undergo a thorough ophthalmological evaluation to facilitate prompt diagnosis and immediate treatment of this rapidly progressive sight-threatening disease.