The Brazilian Health Ministry has confirmed that the Zika virus has caused “most” of the microcephaly cases recorded following its discovery in the country.
This month, doctors have reported 46 more cases of microcephaly, which occurs when the brain does not form properly during pregnancy or after birth. The new cases push the total since October to 508. The Wall Street Journal reports:
Of the 5,280 cases initially suspected to be Zika-related microcephaly reported in Brazil since Oct. 22, a total of 837 have been rejected—either because tests showed they weren’t microcephaly at all or showed they were microcephaly, or another form of alteration to the central-nervous system, but were caused by other factors.
Between Oct. 22 and Feb. 6, there have been 108 suspected microcephaly-related infant deaths nationwide. Of these, a total of 27 have been confirmed as related to microcephaly or some other alteration of the nervous system, the ministry said. Eleven deaths have been ruled not related to microcephaly, and 70 cases are still under investigation.
Authorities continue to investigate another 3,935 cases.
A doctor in Brazil recently discovered numerous microcephaly cases that predate the Zika outbreak. Dr. Sandra Mattos found data on 100,000 newborns since 2012. At least 1,600 babies born in the last years had microcephaly or smaller-than-normal heads.
“We were very, very surprised,” stated Mattos. “Borderline cases seem to be present all along.”
According to CBC News:
Brazilian authorities set the criterion for microcephaly, a measurement of head size, at 32 centimetres for full-term births. Doctors were asked to report babies at or below that level for further investigation.
Mattos said the data analysis also confirmed the number of severe microcephaly cases increased starting in October or November of 2014.
The Centers for Disease Control (CDC) claims rubella, toxoplasmosis, cytomegalovirus, severe malnutrition, alcohol, drugs, and toxic chemicals can cause microcephaly.
CDC director Tom Frieden confirmed scientists found the Zika virus in the tissue of infants who died from microcephaly. He stopped short of claiming that Zika caused the birth defect.
Mattos told the World Health Organization (WHO) that “other potential factors need to be considered,” since 80 percent of the microcephaly babies live in northeast Brazil. The Colombian government confirmed 3,100 cases of pregnant women with Zika, but none of the babies have microcephaly.
Yale University School of Public Health Professor Albert Ko believes the cases of microcephaly in Brazil are just the start of concerns about birth defects linked to the Zika virus.
“It seems like microcephaly may just be the tip of the iceberg,” he stressed, adding:
The preliminary evidence is that [some] babies who don’t have microcephaly may also have neurological lesions or birth defects that are not as obvious as microcephaly. We’re really concerned because of Zika, but we need to rule out other causes of congenital infection to really make sure.
Microcephaly has received the most attention, but Ko found other problems with the infants.
“We’re seeing a spectrum. Many have fairly severe central nervous system lesions,” he explained. “There are also a lot of calcium deposits. … Those can cause seizures and cause impairment in terms of function for the brain.”
Brazilian authorities and scientists have advised women to delay pregnancy.
“It’s a very personal decision, but at this moment of uncertainty, if families can put off their pregnancy plans, that’s what we’re recommending,” said Angela Rocha, the pediatric infectologist at Oswaldo Cruz Hospital in Brazil.