As Zika Spreads, Evidence of Link to Birth Defects Grows

August 19, 2016 04:18 pm News Staff

According to the Florida Department of Health (DOH), there have been 36 CDC-confirmed cases of nontravel-related Zika virus infection in the state as of Aug. 19(www.floridahealth.gov). That total includes five individuals with previously confirmed cases of local transmission that are now being connected to what is thought to be a second site of active transmission in the Miami Beach area. This second area covers slightly less than one-and-a-half square miles and is located well outside of the one-square-mile area in Miami-Dade County -- the Wynwood neighborhood -- where active transmission was orginally determined to be taking place.

[Newborn with bilateral club foot, also called congenital talipes equinovarus]

Given these troubling numbers, the CDC issued an unprecedented travel advisory(www.cdc.gov) earlier this month warning pregnant women to avoid visiting the original one-square-mile area in Miami-Dade County and has since expanded its advisory to include this second site. At this point, there have been 63 Zika infections reported in pregnant women in the state, and the latest CDC numbers(www.cdc.gov) (i.e., as of Aug. 11) show there are 529 pregnant women with any laboratory evidence of possible Zika infection in the continental United States and another 691 in the U.S. territories.

With these numbers expected to continue to rise, it's even more disturbing that evidence showing the devastating effects Zika virus can have on the fetus is growing. The link between maternal infection with the virus to microcephaly in infants has been firmly established, but now a new study has brought to light another birth defect that appears to be tied to the virus.

Study Highlights
  • Florida health officials are investigating what appears to be a second area of local mosquito-borne Zika virus transmission in the Miami Beach area.
  • A study published Aug. 9 by The BMJ explored the association between prenatal Zika virus infection and arthrogryposis multiplex congenita, which is characterized by joint contractures at birth.
  • The Texas Department of State Health Services announced that an infant had died in Harris County shortly after birth from complications of microcephaly related to Zika virus infection.
     

Congenital Zika Syndrome With Arthrogryposis

A study published Aug. 9 by The BMJ(www.bmj.com) explored the association between prenatal Zika virus infection and arthrogryposis multiplex congenita, which is characterized by joint contractures at birth -- particularly in the arms and legs.

Previously, mounting evidence led the CDC to conclude there is a causal relationship between prenatal Zika virus infection and microcephaly and other serious brain anomalies. However, little is known about other potential health problems that Zika virus infection might cause during pregnancy. Before 2015, there were no reports of an association between congenital viral infections and arthrogryposis.

The BMJ study was based on a retrospective review of medical records at the rehabilitation center of the Association for Assistance of Disabled Children in Pernambuco, Brazil, looking for children with a diagnosis of congenital infection presumably caused by Zika virus who had arthrogryposis. Researchers found seven infants who fit this description, met the criteria for brain imaging that suggested congenital infection, and had negative test results for the five other primary causes of microcephaly (i.e., toxoplasmosis, cytomegalovirus, rubella, syphilis and HIV).

These children underwent neurological and orthopedic examinations along with several other investigations: radiography, brain CT or brain MRI without contrast, high-definition ultrasonography of the joints (with specific attention to cartilage, synovia, pericapsular structures and muscular tissue around joints), nerve conduction studies, and needle electromyography. Four children also underwent MRI of the spine.

All seven children underwent fundoscopic assessment in accordance with state protocol, and six also underwent hearing screening by otoacoustic emissions or brainstem evoked potentials.

Arthrogryposis was present in both the arms and the legs of six of the children and in only the legs of the seventh. The chest was barrel-like in four children.

Leg deformities observed included congenital clubfoot in six children, which was bilateral in three; knee flexion contracture in five children, which was bilateral in three; and hyperextension associated with subluxation of the knee in three children, which was bilateral in two. Contractures of hip flexion, adduction and external rotation associated with irreducible bilateral dislocation that is not reducible to maneuver of Ortolani were present in all seven children.

Arm deformities identified were camptodactyly in six children, which was bilateral in five, and deformations of flexion in the second to fifth chirodactylus in all seven children. Adduction of the thumb was present in five children and abduction of the thumb was seen in two; deformities in hyperextension of the elbow were observed in four children; bilateral flexion contracture was present in two; and decreased range of motion of the shoulder with contracture in adduction and internal rotation affected two children.

On high-definition ultrasonography of the joints, no evidence of abnormalities was seen.

All seven of the infants showed abnormalities of cortical development on brain imaging, with calcifications predominantly in the cortex and subcortical white matter (especially in the junction between the cortex and white matter), reduction in brain volume, ventriculomegaly, and brainstem and cerebellar atrophy.

In a news release(www.bmj.com), the study authors called for further research with a larger number of cases to study the neurological abnormalities behind arthrogryposis. But they also suggested that children with the condition should receive orthopedic follow-up to address their risk for developing musculoskeletal deformities secondary to neurological impairment.

Based on these observations, the researchers said "congenital Zika syndrome should be added to the differential diagnosis of congenital infections and arthrogryposis."

Second U.S. Zika Death Is Tied to Birth Defect

Just this past week, the Texas Department of State Health Services announced in a news release(www.dshs.texas.gov) that an infant had died in Harris County shortly after birth from complications of microcephaly related to Zika virus infection. It is only the second Zika-related death seen to date in the United States.

The child's mother had traveled to Latin America, where she was infected with Zika virus during her pregnancy, and the baby acquired the infection in the womb.

"Zika’s impact on unborn babies can be tragic, and our hearts are with this family," said John Hellerstedt, M.D., Texas Department of State Health Services commissioner, in the news release. "Our central mission from the beginning has been to do everything we can to protect unborn babies from the devastating effects of Zika."

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