Neonatal Viral Infections: Herpes, CMV, And Zika

Neonatal viral infections can begin with subtle findings and progress rapidly. A newborn may initially appear well while carrying a serious risk of encephalitis, respiratory failure, congenital brain injury, or long-term developmental impairment. Herpes simplex virus (HSV), cytomegalovirus (CMV), and Zika virus require different diagnostic strategies, yet all demand careful attention to maternal history, timing of exposure, physical examination, and follow-up.

These infections also illustrate why perinatal medicine depends on cooperation between obstetricians, neonatologists, midwives, microbiologists, neurologists, and public health teams. The scientific focus associated with the FAOPS 2020 congress site included perinatal and neonatal medicine, fields in which rapid communication and shared clinical standards are particularly important.

The clinical picture varies according to whether infection was acquired before birth, during delivery, or after birth. Congenital CMV and Zika are primarily prenatal concerns, while neonatal HSV is frequently linked to exposure around delivery, although postnatal transmission can occur. Recognizing these pathways helps clinicians choose the right tests and begin treatment before irreversible injury develops.

Why Early Recognition Matters

Neonates often have an incomplete or nonspecific inflammatory response. Fever may be absent, and symptoms such as poor feeding, lethargy, temperature instability, jaundice, apnea, or respiratory distress can resemble bacterial sepsis. A vesicular rash is a useful clue in HSV infection, but many affected infants have no visible skin lesions. Clinical vigilance must therefore extend beyond obvious signs.

Maternal infection history can refine risk without replacing neonatal evaluation. Recurrent genital HSV, primary HSV near delivery, inadequate prenatal care, travel to an area with active Zika transmission, and an unrecognized maternal CMV infection all carry different implications. Documentation should include gestational age, rupture of membranes, delivery mode, maternal symptoms, prenatal imaging, and the newborn’s neurologic and ophthalmologic findings.

A diagnostic plan should be guided by the suspected route and timing of infection. Blood, urine, saliva, cerebrospinal fluid, placental tissue, and lesion swabs each have specific uses and limitations. Testing too late, using the wrong specimen, or interpreting a positive result without clinical context can lead to missed disease or unnecessary treatment.

Neonatal Herpes Simplex Virus

HSV-1 and HSV-2 can cause disease in the skin, eyes, and mouth; localized central nervous system infection; or disseminated disease involving the brain, liver, lungs, and other organs. Symptoms commonly appear during the first four weeks of life, but clinicians should consider HSV in an ill infant beyond that period when compatible signs are present. Disseminated infection may resemble bacterial septic shock, with coagulopathy, hepatitis, respiratory compromise, or cardiovascular instability.

Evaluation generally includes polymerase chain reaction testing of cerebrospinal fluid, blood testing, and swabs from conjunctivae, mouth, nasopharynx, rectum, and any skin lesions. Liver enzyme elevation, thrombocytopenia, seizures, and unexplained shock increase concern. A lumbar puncture is important when safe, although antiviral therapy should not be delayed while awaiting every result if the clinical suspicion is substantial.

Intravenous acyclovir is the standard initial treatment. The duration depends on disease category, with longer courses required for central nervous system or disseminated infection. Infants with central nervous system disease require repeat cerebrospinal fluid testing to document viral clearance, followed by extended oral suppressive therapy in many treatment protocols. Ophthalmologic assessment is essential when eye involvement is possible, and survivors need developmental, neurologic, hearing, and vision monitoring.

Congenital Cytomegalovirus

CMV is a widespread herpesvirus and the leading infectious cause of congenital sensorineural hearing loss in many settings. Maternal primary infection, reinfection, or reactivation can transmit the virus across the placenta. Some infants have signs at birth, including petechiae, jaundice, hepatosplenomegaly, microcephaly, thrombocytopenia, abnormal brain imaging, growth restriction, or chorioretinitis. Others appear healthy initially and later develop hearing or developmental problems.

Diagnosis in a newborn requires attention to timing. Detection of CMV by polymerase chain reaction in saliva or urine within the first three weeks of life supports congenital infection. Testing after this period cannot reliably distinguish congenital infection from postnatal acquisition. Saliva samples can be affected by breast milk contamination, so a positive saliva result is commonly confirmed with urine testing.

Neuroimaging, ophthalmologic examination, blood counts, liver studies, and formal hearing assessment help define severity. Antiviral therapy with valganciclovir may be considered for selected symptomatic infants, particularly those with central nervous system involvement, under specialist supervision because of potential neutropenia, anemia, thrombocytopenia, and liver toxicity. Every infant with congenital CMV requires structured audiologic and developmental surveillance, since hearing loss may emerge or progress after the newborn period.

Congenital Zika And Fetal Injury

Zika virus infection during pregnancy can produce a congenital syndrome involving microcephaly, severe cortical thinning, intracranial calcifications, ventriculomegaly, abnormal eye findings, arthrogryposis, and neurologic dysfunction. The risk is associated with the timing of maternal infection and may be significant even when the mother experienced mild or no symptoms. A normal head circumference at birth does not eliminate the possibility of later developmental or neurologic concerns.

Assessment should include a detailed examination, head circumference measured against appropriate gestational-age standards, neurologic evaluation, hearing screening, ophthalmologic assessment, and neuroimaging when indicated. Maternal and infant laboratory testing must be interpreted according to local public health guidance because antibody cross-reactivity with other flaviviruses can complicate serologic results. The differential diagnosis should include other congenital infections, genetic conditions, and noninfectious causes of brain abnormalities.

There is no established antiviral treatment that reverses congenital Zika-related injury. Care is therefore centered on early recognition, seizure management, nutritional and respiratory support, physical and occupational therapy, and coordinated developmental services. Families benefit from clear counseling about uncertainty, since the severity of impairment can vary widely and some consequences become apparent only as the child develops.

Comparing Clinical Pathways

The three infections differ in transmission, timing, signature findings, and treatment. A concise comparison can help organize the initial assessment, although local protocols and specialist consultation remain necessary.

Timing is especially important when interpreting laboratory results. HSV polymerase chain reaction can identify active central nervous system infection, while CMV testing must be completed early to establish congenital origin. Zika testing is more dependent on exposure assessment, public health recommendations, and the limitations of serology.

The table also highlights a central difference in treatment goals. HSV often requires urgent antiviral therapy to prevent death and neurologic injury. CMV treatment decisions weigh disease severity against medication toxicity. Zika care emphasizes prevention of secondary complications and sustained developmental support because an antiviral cure is unavailable.

Screening, Treatment, And Follow-Up

A newborn with suspected HSV should receive prompt stabilization alongside diagnostic testing. Antiviral therapy is time-sensitive, particularly when seizures, abnormal liver function, sepsis-like illness, or maternal primary infection near delivery is documented. Empiric antibacterial therapy may be started when bacterial sepsis remains possible, since viral and bacterial disease can coexist or look similar during the first hours of illness.

For CMV, the care team should establish whether infection is congenital, assess the extent of organ involvement, and communicate results to audiology and developmental services. Hearing surveillance should continue even after an initial pass on newborn screening. Infants with neurologic abnormalities may need repeated imaging, early intervention, feeding support, and evaluation for cerebral palsy or epilepsy.

Zika-exposed infants require individualized monitoring rather than a single reassuring examination. Growth, tone, vision, hearing, feeding, sleep, motor skills, language, and social development should be tracked over time. Families should receive practical information about appointments and warning signs, with interpretation provided in a culturally and linguistically appropriate manner.

Neonatal stabilization remains part of infection care. Airway management, ventilation, seizure control, glucose monitoring, temperature regulation, fluid management, and safe transport may all be necessary before a definitive diagnosis is available. Guidance such as these resuscitation updates reinforces the importance of maintaining current emergency skills while infectious disease investigations proceed.

Building A Coordinated Care Plan

A reliable clinical pathway should connect the delivery room, neonatal unit, laboratory, infectious disease service, and outpatient providers. Written protocols reduce delays in obtaining cerebrospinal fluid, urine, saliva, lesion swabs, imaging, and specialist assessments. They also clarify when public health notification, maternal testing, or evaluation of other household members is required.

Families need information that is accurate without being alarmist. Counseling should explain the suspected route of infection, the reason for each test, expected treatment duration, possible medication adverse effects, and the importance of follow-up. Parents should know that an apparently healthy newborn can still require hearing, vision, neurologic, or developmental surveillance.

Useful priorities for neonatal teams include:

• Review maternal infection, travel, vaccination, laboratory, and delivery histories at admission.
• Start empiric acyclovir promptly when neonatal HSV is reasonably suspected.
• Confirm congenital CMV with appropriately timed urine or saliva PCR.
• Assess Zika-exposed infants with neurologic, eye, hearing, growth, and developmental evaluations.
• Create a documented follow-up schedule before discharge, including responsible specialists and testing dates.

Perinatal conferences and professional networks can strengthen these systems by sharing case experience, laboratory updates, and evidence-based protocols. The most effective response to neonatal viral disease combines immediate bedside action with careful long-term planning.

Clinicians, educators, and families can use established perinatal resources to review diagnostic pathways, emergency care, and follow-up standards, then adapt them to local laboratory capacity and public health guidance. Applying that knowledge consistently gives vulnerable newborns the best opportunity for early treatment, meaningful developmental support, and coordinated care from birth onward.