Findings from an epidemiologic investigation conducted in Colombia of patients with clinical symptoms of Zika virus suggests that infection occurring during the 3rd trimester of pregnancy is not linked to microcephaly in the fetus.
For this study, researchers utilized Colombia’s national population based surveillance system, Instituto Nacional de Salud (INS), to understand and characterize the extent of Zika’s impact in Columbia.
To assess the epidemic, researchers reviewed patients exhibiting clinical symptoms of Zika infection, such as fever and rash, headache, extreme fatigue, increased pain, and/or conjunctivitis without pus, from August 9, 2015 to April 2, 2016.
Analysis showed that there were 65,726 cases of Zika virus infection throughout Colombia during the surveillance time period, with two times the number of females infected than males; about 12,000 pregnant women were infected.
Among 616 women who were infected in the 3rd trimester of their pregnancy, there was no incidence of microcephaly or other brain abnormalities observed in the fetus; and 82% of the women had infants who were born at term and at healthy weights.
To help understand what the finding means and public health implications, Dr. Peter Hotez, dean of the Baylor College of Medicine National School of Tropical Medicine and Professor of Pediatrics and Molecular Virology & Microbiology at Baylor College of Medicine, spoke with BioNews Texas.
What do you think is important about the findings from the NEJM’s epidemiologic investigation of Colombia’s women in the 2nd and 3rd trimester?
The researchers did not find evidence of microcephaly within 2nd and 3rd trimester, and concluded that it is mostly dependent on a 1st trimester infection. They may be right—if you look at microcephaly, and the term microcephaly is a bit of a misnomer in some ways, a better term is an older term from the 1990s called “fetal brain disruption sequence”, because the virus actually halts the development of the fetal brain by infecting neuron progenitor cells and neuro stem cells—so to me that suggests an early pregnancy event and probably something that most likely happens from Zika virus infection during the first trimester.
Now having said that there may be neurological consequences that go beyond the full fetal brain disruption sequence/microcephaly, there could be more subtle, yet serious neurological deficits going on. I wrote about this in a paper in JAMA Pediatrics that came out a couple of weeks ago. What I say in that paper is “what about the non-structural defects?” Could Zika virus be happening in 2nd and 3rd trimesters even though it is not causing microcephaly or fetal brain disruption sequence, bad things are still happening to the baby. I think that is a real concern and we don’t know—we are still on a steep learning curve about this virus.
The other concern that I have is what about the effects after the baby is born? If an infant gets infected in the first year of life while the brain is still developing, could there be consequences there also? Again it wouldn’t be microcephaly but it still could create bad neurologic outcomes. So I think what I wrote in my JAMA piece is that we are going to need a generation of pediatric neurologists, infectious disease experts, and child psychiatrists to really investigate the long-term consequences of Zika virus infection—not only for microcephaly, but for other disorders.
So it is paramount that a Zika Bill passes so there will be funds available for that?
You would think. My frustration is that Congress doesn’t think this thing is real and they are willing to allow ideological arguments to interfere with public health.
About Dr. Peter Hotez
Dr. Peter J. Hotez, is Dean of the National School of Tropical Medicine and Professor of Pediatrics and Molecular Virology & Microbiology at Baylor College of Medicine where he is also chief of a new Section of Pediatric Tropical Medicine and the Texas Children’s Hospital Endowed Chair of Tropical Pediatrics. He is the President of the Sabin Vaccine Institute.
Internationally recognized, Hotez leads the only product development partnership for developing new vaccines for hookworm infection, schistosomiasis, and Chagas disease. In 2006 he co-founded the Global Network for Neglected Tropical Diseases to provide access to essential medicines.
He obtained his undergraduate degree in molecular biophysics from Yale University (1980); earned a PhD degree in biochemical parasitology from Rockefeller University (1986), and received his MD from Weil Cornell Medical College (1987). Hotez authored more than 400 original papers and is the author of the book Forgotten People, Forgotten Diseases.
He is the founding editor-in-chief of PLoS Neglected Tropical Diseases. In 2015, Hotez was selected by the U.S. State Department to serve as a United States Science Envoy.