A group of Brazilian scientists on Monday released a study proving the relationship between the Zika virus and cases of babies being born with abnormally small skulls, a condition known as microcephaly which has increased exponentially in Brazil in recent months.

The study was conducted by researchers at the Universidad Federal in Rio de Janeiro and the non-profit IDOR institute, and it was published in Science magazine.

So far, the World Health Organization has not acknowledged the existence of scientific proof of the connection between the virus and fetal deformities, although WHO Director-General Margaret Chan has admitted that “the circumstantial evidence is overwhelming.”

The researchers proved that Zika destroys neural tissue as it is forming, and they performed an experiment on fetal stem cells, called neurospheres, and on cerebral organoids, tissues created in the laboratory that imitate the cerebral cortex.

One of the scientists heading the study, neurobiologist Stevens Rehen, said at a press conference that the virus caused “great alterations” and the destruction of neural tissues in just six days and a reduction in the size of the organoids.

The cerebral organoids were infected with Zika over the course of 11 days, a period that would be equivalent to the development of a brain during the first month of gestation, and researchers observed that the tissue grew by 40 percent less than normal.

Neuroscientist Patricia Garcez said that the researchers noted “how aggressive this virus is.”

The experiment focused on the effects on developing brains, and so it does not provide data on the possible link between Zika and Guillain-Barre syndrome, which manifests itself in adults and is also thought to be linked to the virus.

Among the 38 countries affected by the Zika outbreak, Brazil is the country that has reported the most cases of microcephaly in newborns, more than 1,000 since last October.

Second study links Zika to new brain disorder

Meanwhile in a different study, scientists in Brazil have also found evidence of a second brain disorder linked to the Zika virus – one with symptoms so similar to multiple sclerosis that some medical personnel initially have difficulty telling them apart.

The new disorder, called acute disseminated encephalomyelitis, or ADEM, is identified in an abstract authored by Brazilian scientist Maria Lucia Brito Ferreira.  She is set to present her findings at an international meeting of neurological scientists meeting April 15-21 in Vancouver, British Columbia.

ADEM is described as a short-term, intense immune attack on the central nervous system, targeting the brain and spinal cords in patients who have recovered from a range of viral or bacterial infections.

Brazilian news site G1 reported that Ferreira, a neurologist at Restoration Hospital in Recife, Brazil, based her findings on the study of 151 patients who visited the hospital between December 2014 and June 2015.

Ferreira observed the patients who had been infected with arboviruses, which include Zika, dengue and chikungunya. Out of these patients, six were diagnosed with Zika. Five patients reported motor dysfunction, vision problems, and one had cognitive decline.

Zika has already been linked with the autoimmune disorder Guillain-Barre that causes swelling in the brain and spinal cord that damages the myelin, a white protective coating that surrounds never fibers resulting in loss of balance and vision, numbness, and weakness.

“Encephalomyelitis, is a serious condition, regardless of etiology. It is more serious than the Guillain-Barré,” Ferreira told G1.

 

The Zika virus in Costa Rica

To date, there have been a total of 12 confirmed cases of Zika infection in Costa Rica.

Of the total, there have been eight indigenous cases, all of which where contracted in the canton of Nicoya, specifically in Nosara and Samara, in the province of Guanacaste. The remaining cases have been “imported” cases of infection, where the patient contracted the virus during a trip abroad.

Health authorities said in March that they had managed to halt the spread of the virus in Nicoya, where all of the indigenous cases of infection have occurred, by eliminating more than 130,000 active and potential breeding sites of the Aedes aegypti mosquito, which spreads Zika as well as the dengue and Chikungunya viruses.

EFE and VOA contributed to this report.