Though much of the concern in the media regarding the toxic effects of Zika virus has focused on brain
findings of microcephaly, the researchers noted that there are a variety of brain abnormalities that can be found in fetuses exposed to the virus, including gray and white matter volume loss, brainstem abnormalities, calcifications, and a condition called ventriculomegaly, where the ventricles, or fluid filled spaces in the brain, are enlarged.
Not exact matches
After taking samples and conducting brain scans, the researchers
found that 41 percent
of mothers
of babies with
microcephaly tested positive for Zika infection in blood or cerebrospinal fluid samples, compared with none
of those whose babies did not have
microcephaly.
The
finding strengthens the evidence that a mother's Zika infection during pregnancy raises her baby's risk
of microcephaly and other brain malformations.
This
finding paves the way to study whether p53 inhibitors could provide the basis
of a future treatment to prevent
microcephaly.
The team who
found a range
of fetal conditions beyond
microcephaly, all linked to the virus, suggest calling it Zika virus congenital syndrome
The
finding of virus in the brain could also be important, since the most devastating impact
of the current outbreak in Brazil appears to be children
of infected mothers born with
microcephaly — abnormally small heads and, in some cases, incomplete brain development.
The virus has been
found in the amniotic fluid
of two fetuses diagnosed with
microcephaly via ultrasound.
It has also been
found in tissues
of a baby with
microcephaly that died shortly after birth.
The
findings — so far observed only in cells and minibrains grown in the lab — offer a possible explanation for the misshapen heads that are the hallmark
of microcephaly, a condition that afflicts some babies infected with Zika.
«Studies
of fetuses and babies with the telltale small brains and heads
of microcephaly in Zika - affected areas have
found abnormalities in the cortex, and Zika virus has been
found in the fetal tissue,» says Guo - li Ming, M.D., Ph.D., a professor
of neurology, neuroscience, and psychiatry and behavioral science at Johns Hopkins» Institute for Cell Engineering.
Such techniques have the potential to enhance research into the origins
of neurodevelopmental and neuropsychiatric disorders such as
microcephaly, lissencephaly, autism and schizophrenia, which are thought to affect cell types not
found in the mouse models that are often used to study such diseases.
They
found an increase in
microcephaly cases and
of Guillain - Barré syndrome.
Researchers have already documented an increase
of microcephaly cases coinciding with the outbreak and have
found evidence
of the virus in brains
of newborns who died, as well as in fluid from the placenta
of infected pregnant women.
But Peter Hotez, dean
of the National School
of Tropical Medicine at Baylor College
of Medicine, said its
findings offer «potentially important» new information about the link between Zika and
microcephaly.
What seems to be universal is that
microcephaly is not the sole
finding but is a consequence
of several brain injuries.
The birth prevalence
of neonatal
microcephaly and other central nervous system malformations greatly increased between 2015 and mid-2016 in Brazil.1 - 3 Several reports1,2,4 - 6 suggested an association between these
findings and Zika virus (ZIKV) infection during outbreaks in Brazil and French Polynesia.
The 3 largest case series
of infants with
microcephaly also reporting congenital contractures
found that, among 35, 48, and 52 infants with
microcephaly and presumed congenital ZIKV infection, isolated clubfoot occurred in 14 %, 10.4 %, and 3.8 % and arthrogryposis in 11 %, 10.4 %, and 5.7 %, respectively.36 - 38 Among a series
of 104 infants under clinical investigation, 7 (6.7 %) with presumed (5 infants) and laboratory - confirmed (2 infants) congenital ZIKV infection had arthrogryposis; 6
of these infants had a head circumference
of at least 2 SD below the mean.41 All had bilateral congenital hip dislocation, which previously has been reported to occur in 30 % to 40 %
of children with arthrogryposis
of various etiologies and 3
of 7 had dislocation or partial dislocation
of 1 or both knees.41, 57
Structural eye anomalies (in particular, microphthalmia and coloboma), cataracts, intraocular calcifications, and posterior ocular
findings have been reported in infants with presumed and laboratory - confirmed prenatal ZIKV infection; however, posterior
findings have been the most prevalent.21,25,28,33,35,36,41 - 43 Case series report chorioretinal atrophy, focal pigmentary mottling
of the retina, and optic nerve atrophy / anomalies.28, 34,37,41 - 43,55 Series
of 20 or more infants with presumed ZIKV - associated
microcephaly report ocular
findings in 24 % to 55 %.28, 33,42 In one study, testing for ZIKV IgM was performed in 24
of 40 infants (60 %) with
microcephaly and the results were positive in the cerebrospinal fluid in 100 %
of those tested.42 The proportion
of infants with ocular lesions did not differ in those with and without testing.42 In that series, first trimester maternal infection and smaller head circumference significantly correlated with the presence
of abnormal ocular
findings.42
Addressing the Zika outbreaks has been a challenge for health officials, and since the first
microcephaly cases were reported in Brazil last year, there has been a nationwide effort to
find practical solutions to the growing threat
of the virus.
A recent increase in the prevalence
of microcephaly in newborn infants and vision - threatening
findings in these infants is likely associated with the rapid spread
of ZIKV.
More than half the infants had
microcephaly, brain calcifications, loss
of brain tissue volume, and other brain structural abnormalities, the researchers
found.
Lyle R. Petersen, MD, director
of vector - borne diseases at the CDC, told the New York Times earlier this week that the agency had
found the Zika virus in four Brazilian babies; two died in the womb, and two had
microcephaly and died shortly after birth.
To see the alternative story about Zika infections, Mike Adams, the Health Ranger, did some studies on Brazilian populations with a high incidence
of microcephaly and did
find that the incidences
of microcephaly corresponded more with environmental toxins.