The news media have been full of the threat to unborn children from an infection with the Zika virus. Yet, there exists a common virus that presents a far more serious threat to a fetus. That virus is called cytomegalovirus, or CMV. According to the U.S. Centers for Disease Control and Prevention (CDC), half of all Americans will have contracted this illness by age 40. There is no cure and the illness can reactivate at any time.
About this time in 2015, Brazilian public health authorities began to receive reports of an unusual number of cases of a birth defect called microcephaly in newborns. It appears that the defect, with other serious defects, is associated with some pregnant mothers contracting a Zika viral illness. This illness was passed to their fetus and seems to have caused, or at least contributed to the development, of these neurological defects.
One of the biggest unknowns about Zika viral illnesses is the number of patients who contract the disease but have a sub-clinical or asymptomatic illness. The incidence of asymptomatic Zika is critical to understanding how the illness is spread. Can an asymptomatic patient pass the virus to another person through sex? Can an asymptomatic patient infect a mosquito that bites him and infect the mosquito enough that the mosquito can transmit the virus to another human?
The headlines are shocking. The New York Times states “Zika Cases in Puerto Rico Are Skyrocketing.” Most other media outlets follow with similar ledes. Is it true? Or, is it just more lies, damn lies and statistics?
In a June 30 post, I discussed a study published in the Lancet, titled “Congenital Zika virus syndrome in Brazil: a case series of the first 1501 live births with complete investigation”. (1) I had raised a number of issues and I wrote the corresponding author for some clarification. I have received a response from Prof. Cesar G Victora.