The Zika virus is primarily transmitted by mosquitoes and poses significant health concerns, especially for pregnant individuals. It can cause severe complications in developing fetuses and newborns.
Transmission to Infants
The Zika virus primarily reaches infants through maternal-fetal (in utero) transmission from a pregnant individual. The virus can persist in the placenta for months, potentially influencing fetal brain development.
Perinatal transmission can also occur around the time of birth if the mother is infected close to delivery. Beyond mosquito bites, Zika can spread through sexual contact with an infected partner. The virus can persist longer in semen than in vaginal fluids.
Congenital Zika Syndrome
Zika virus infection during pregnancy can lead to a range of birth defects and health problems collectively known as Congenital Zika Syndrome (CZS). One of the most recognized and severe manifestations is microcephaly, a condition where a baby’s head is smaller than expected for their age and sex, often indicating that the brain has not developed properly. Babies with severe microcephaly may have a partially collapsed skull and reduced brain tissue.
Beyond microcephaly, CZS can involve other brain abnormalities, including neural tube defects, lissencephaly (absence of brain folds), hydrocephalus, missing brain structures, and brain atrophy. Common eye defects include macular scarring, retinal mottling, chorioretinal abnormalities, and optic nerve abnormalities, leading to vision problems. Infants may also experience hearing loss, joint problems like congenital contractures (similar to arthrogryposis), and hypertonia (stiff muscles). Seizures, feeding difficulties, and developmental delays are additional concerns. Not every baby exposed to Zika will develop all these conditions; however, the infection increases the likelihood of such issues, and some infants may appear healthy at birth but develop problems later.
Identifying and Supporting Affected Infants
Identifying Zika virus infection in infants involves a combination of testing and clinical evaluations. Newborns can be tested for the virus using samples of blood or urine for the presence of Zika virus RNA or antibodies, ideally within the first few days after birth. In some cases, cerebrospinal fluid may also be tested.
Imaging studies, such as a postnatal head ultrasound or MRI, are performed to assess for brain abnormalities, even if prenatal ultrasounds appeared normal. A comprehensive physical examination, including a detailed neurologic assessment, is conducted, alongside an ophthalmologic evaluation and hearing assessment, often using auditory brainstem response (ABR) testing, before one month of age. Support for infants diagnosed with CZS is multidisciplinary, involving various specialists to manage specific symptoms and developmental needs. The care focuses on providing developmental support and early intervention services rather than a cure, aiming to maximize the child’s potential. Families also receive ongoing psychosocial support and assistance with coordinating their child’s care.
Preventing Exposure During Pregnancy
Preventing Zika virus exposure during pregnancy involves avoiding infection. Pregnant individuals or those considering pregnancy should avoid travel to areas with active Zika virus transmission. If travel cannot be avoided, consult a healthcare provider before the trip.
Mosquito bite prevention is key. This includes using EPA-approved insect repellents (e.g., DEET or picaridin), wearing long-sleeved shirts and pants, and staying in places with air conditioning or intact window and door screens. Eliminating standing water around homes also reduces mosquito breeding sites. Practicing safe sex, such as using condoms consistently or abstaining from sexual activity, is advised if a partner has traveled to or resides in a Zika-affected area.