A team of researchers determined how the Zika Virus reaches the fetus in the infected pregnant woman in a study published on Friday. Until now, the specific cells involved in the access to the growing fetus remained unknown, and the discovery may offer clues to develop antiviral treatments and preventive measures.
The cells involved in the fetus infections are the Hofbauer cells, which have direct access to fetal blood vessels. Researchers determined that the virus could infect and proliferate in the immune cells from the placenta without killing them, according to the study published in Cell Host & Microbe.
“One group has recently discovered viral antigen in Hofbauer cells collected from placental tissue of a fetus that unfortunately died as a result of Zika virus infection,” said senior author and Assistant Professor of Pediatrics at the Emory University School of Medicine, Mehul Suthar.
The team from Emory University studied small samples of donated human placenta to identify the cell types that may be vulnerable to the Zika virus infection by using a strain currently circulating in Puerto Rico.
“Our study indicates that this cell type may be a target for Zika virus in the placenta and replication in these cells may allow the virus to cross the placental barrier and enter the fetal circulation,” added co-author Rana Chakraborty, a pediatric infectious disease specialist.
One explanation as how this can reach this particular cells is by an initial infection on the outermost layer of cells that surrounds and nurtures the fetus. Although previous research has denied that this layer lets the virus go through, according to a press release published in EurekAlert.
Also, the gathered samples showed different levels of infections. These differences in the viral replication could offer the key as how to protect and prevent further spread of the virus. What the study suggested is that not everyone is predisposed to having the virus replicated in the placenta. However, the full meaning of this needs to be further explored, Suthar said.
A growing problem in the U.S.
Over the last weeks, several Zika cases have been discovered across the United States. Becuase of this, preventive measures are being taken by health officials to avoid further spread of the virus.
Health officials from Alabama have reported five cases so far. The infected had recently traveled to countries known to have the Zika epidemic. One the patients lives in Jefferson County. According to a press release from the Alabama Department of Public Health, the other affected are from Houston County.
Four other cases have been discovered as well in Tarrant County, Texas, according to Public Health Director Vinny Taneja. None them were transmitted by local mosquitoes. In at least one case, the disease was brought from Puerto Rico, the same strain studied at the Emory University, as reported by CBS Local.
With the latest cases, public health departments are making sure the virus stated controlled by increasing its surveillance. The infected patients will be asked for names of sexual partners and other members of the household, which will be constantly monitored for the illness.
However, these cases are not the only ones found across the country, according to the U.S. Centers for Disease Control and Prevention (CDC) data. Exactly 591 Zika cases have been officially confirmed by the CDC in the United States, with most of the people infected from Florida, New York, and California, respectively.
The infected patients in most of the U.S. states were qualified as travel-associated cases, which means that the virus is not exactly present in those states, a positive outcome to avoid the local infection. Other U.S. territory such as Puerto Rico has nearly 100 confirmed cases originated in the area, while the Virgin Islands had only 15.
Health authorities recommend people with constant contact with the infected ones to use insect repellent to prevent the spread of the disease through mosquito bites. However, there are other forms of transmission. The animal responsible for carrying the virus is known as the Aedes aegypti.
The symptoms of the disease are fever, rash, joint pain, and conjunctivitis or red eyes. The illness is usually mild with its symptoms, which last for several days to a week after being bitten by an infected mosquito, according to the CDC.
— Zika News (@Zika_News) May 30, 2016
Infection not only through mosquito bites
Brazil’s authorities have informed in the past that the Zika virus has been found in patient’s saliva and urine, making possible the transmission via fluids and adding more difficulties to stop the spread.
The virus was previously thought to be transmitted primarily from mosquito bites. Nevertheless, recent findings have proven that the presence of the virus in the saliva and urine is something to worry about. U.S. officials also assured that it could be transmitted through sex and blood transfusions and that cases from these kinds of infections have been already found.
Researchers used genetic testing to identify the Zika virus in the corporal fluids from two patients who had previously tested positive for the virus. They concluded that the virus was active, meaning that could lead to a potential infection in a healthy person.
Scientists from the Oswaldo Cruz Foundation said that further investigation is needed, but they cannot say that there is no possibility of transmission.
“In light of the possibility of being in contact with someone who is infected, do not kiss, obviously,” Dr. Paulo Gadelha, the foundation’s president, told reporters.