Brazil is the country hit hardest by Zika, with thousands of cases
of microcephaly reported so far.
Among cases
of microcephaly reported in Colombia so far this year, four babies had laboratory evidence of a Zika virus infection.
Not exact matches
The agency said there have been recent variations in the number
of cases
reported in the region and, while the level
of risk is unknown, Zika virus infection during pregnancy causes severe birth defects, including
microcephaly and other severe brain abnormalities.
The number
of babies born with
microcephaly in northeast Brazil, the country hardest hit by the Zika outbreak, has increased about 40-fold from baseline levels in the last six months, according to
reports from Brazil's Ministry
of Health.
Menabde said currently 34 countries had
reported the Zika virus outbreak, mostly in the Americas and Caribbean, and seven
reported an increase in cases
of microcephaly.
A 2006 study
of 77 pregnant women infected with West Nile virus
reported that two had infants with
microcephaly, the birth defect lately associated with Zika that results in unusually small and damaged brains.
As we
report in a collection
of stories, much remains unclear, including the relationship between Zika infection and
microcephaly and how best to combat the mosquitoes that spread the disease.
A far higher number
of babies in Colombia have developed
microcephaly related to Zika virus infections than previously
reported.
In contrast, the latest World Health Organization (WHO) «situation
report,» with data current to 7 December, said that Colombia had only
reported 60 cases
of microcephaly or central nervous system malformations potentially linked to Zika.
Now, it is being deployed to monitor the Zika as it spreads beyond Brazil, where
reports last August
of fetal deaths and newborns with brain disorders including
microcephaly, a devastating condition that results in abnormally small brains and heads, began to trickle in.
He said Colombian health authorities would have to address questions about the timing
of their
reporting Zika - positive cases
of microcephaly to WHO.
Earlier this year, the country's tally
of microcephaly cases seemed smaller than expected, given the
reported rise in Zika infections.
He continues, «There is a clear temporal association between the increased
reporting of cases
of microcephaly and
of GBS and the Zika virus outbreak.
As
of March 30, the CDC has
reported 312 cases
of the Zika virus in the United States and heightened its efforts in response to Zika and the cases
of microcephaly and other neurological disorders associated with the virus.
Even as the Zika virus becomes more prevalent — the Centers for Disease Control
reports that the number
of U.S. infants born with
microcephaly and other birth defects is 20 times over the normal rate — researchers are still trying to fully pin down the identifying consequences
of the viral infection.
The research team
reported that evidence
of microcephaly and related skull abnormalities was present in 70 percent
of the infants studied, though often it was subtle.
In another paper, published yesterday in Morbidity and Mortality Weekly
Report, researchers from Brazil and the United States report that Zika virus was present in brain tissue from two newborns in the Brazilian state of Rio Grande do Norte who were born with microcephaly and died a few hours after
Report, researchers from Brazil and the United States
report that Zika virus was present in brain tissue from two newborns in the Brazilian state of Rio Grande do Norte who were born with microcephaly and died a few hours after
report that Zika virus was present in brain tissue from two newborns in the Brazilian state
of Rio Grande do Norte who were born with
microcephaly and died a few hours after birth.
Since October, Brazil has
reported more than 4,000 suspected cases
of microcephaly in areas with Zika circulation.
Although Zika infections typically cause only mild symptoms, concerns have been heightened by Brazil's
reports of an unusual increase in
microcephaly — unusually small head size — in babies born in areas where the virus is circulating.
The
report demonstrates phenotypic variability in regard to the presence
of observed
microcephaly as well as the degree
of brain damage and affected brain structures with congenital ZIKV infection.
This prospective study was conducted in Campina Grande, the second largest city in the state
of Paraíba, which has
reported the second highest prevalence
of microcephaly at birth in Brazil.
In addition, the mechanism by which the ZIKV infection can cause fetal brain damage is not known, and some
reports suggest that the virus is able to evade the normal immunoprotective responses
of the placenta.15 Zika virus is not the only pathogen associated with neonate
microcephaly.
In the recent case series, most infants with probable congenital ZIKV infection were noted to have craniofacial disproportion (95.8 %) and, to a lesser degree, biparietal depression (83.3 %), prominent occiput (75 %), and excess nuchal skin (47.9 %).38 Features supportive
of the FBDS phenotype scattered through published
reports include redundant scalp, 27,36,39,41 occipital prominence and / or overlapping sutures,14,20,22 - 24, 26,27,38 and typical craniofacial appearance with disproportion.13, 27,33,34,40 The FBDS phenotype is also prevalent in ZIKV - related media.47 Among infants with severe
microcephaly, the pattern appears to be consistent, although the degree
of cranial vault deformation varies.
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
So far, Colombia has
reported 11 such cases
of Zika - linked
microcephaly.
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
Contracted through the bite
of an infected mosquito or through sexual or other modes
of transmission, Zika virus (ZIKV) infection can be prenatally passed from mother to fetus.1 The virus was first identified in the region
of the Americas in early 2015, when local transmission was
reported in Brazil.2 Six months later, a notable increase in the number
of infants with congenital
microcephaly was observed in northeast Brazil.3, 4 Clinical, epidemiologic, and laboratory evidence led investigators to conclude that intrauterine ZIKV infection was a cause
of microcephaly and serious brain anomalies.5 - 7 However, as with other newly recognized teratogens, these features likely represent a portion
of a broader spectrum.
In their follow up modelling study they
reported Zika virus infection during the first trimester
of pregnancy led to higher than expected rates
of microcephaly.
The FBDS phenotype has been
reported in an infant with laboratory - confirmed ZIKV infection, 13 in a neuroimaging
report documenting cranial bone collapse in infants born to mothers with suspected ZIKV infection during pregnancy, 14 and a recent case series
of infants with probable ZIKV - associated
microcephaly.38 In 3
of the largest case series
reporting 35, 48, and 104 infants primarily with suspected congenital ZIKV infection, 33,37,38 approximately two - thirds
of infants had severe
microcephaly.
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.
We
report the integration
of transcriptome sequencing (RNA - seq), which surveys all mRNAs to reveal functional impacts
of variants at the transcription level, into the gene discovery framework for a unique human disease,
microcephaly - micromelia syndrome (MMS).
Loss
of function mutations in CTNNB1 have been
reported in individuals with intellectual disability [MIM # 615075] associated with peripheral spasticity,
microcephaly and central hypotonia, suggesting a recognisable phenotype associated with haploinsufficiency for this gene.
Results: Here, we
report six patients with
microcephaly, facial dysmorphism, including exophthalmos, nevus flammeus
of the glabella and joint contractures with a suspected BOS posture in five out
of six patients.
Eighty - five percent
of the fetuses or infants with potentially Zika - associated birth defects in this
report had brain abnormalities or
microcephaly, with most having both
microcephaly and specific brain abnormalities.
The included birth defects were based primarily on case
reports of outcomes occurring in association with Zika virus infection during pregnancy; there is more evidence for some
of these birth defects than for others, and a causal link has not been established for all.5,10,12,21 - 27 Because much
of the focus to date has been on
microcephaly and brain abnormalities, data were summarized in 2 mutually exclusive categories: (1) brain abnormalities with or without
microcephaly regardless
of the presence
of additional birth defects and (2) neural tube defects and other early brain malformations, eye abnormalities, and other consequences
of central nervous system dysfunction among those without evident brain abnormalities or
microcephaly.
Since the Zika epidemic began last spring, it's believed there have been more than 5,600 suspected or confirmed cases
of microcephaly in Brazil, the World Health Organization
reported Friday.
Brazil has
reported the vast majority
of cases
of a Zika - linked birth defect called
microcephaly, which causes babies to be born with abnormally small heads and malformed brains.
«The emergence
of Zika virus in the Americas has coincided with increased
reports of babies born with
microcephaly,» said study author Dr. Heron Werner Jr.,
of the radiology department at Rio de Janeiro's Clinica de Diagnostico por Imagem.
Eleven
of these babies were diagnosed with
microcephaly — an abnormally small head and brain — and other neurologic complications associated with Zika syndrome, the researchers
reported.
On Wednesday, U.S. health officials
reported that traces
of the Zika virus had been identified in the tissue
of two babies who died in Brazil from
microcephaly.
Since evidence suggests that pregnant women with Zika but without symptoms can also have babies with
microcephaly, the agency will now
report all pregnant women with evidence
of Zika virus.
Brazil, especially, has
reported the vast majority
of cases
of Zika - linked
microcephaly.