Zika virus might replace Rio Olympics
The World Health Organisation (WHO) on Saturday rejected a call to move or postpone the impending Rio Olympics over the Zika virus outbreak.
The health watchdog said in a statement that “based on current assessment, cancelling or changing the location of the 2016 Olympics will not significantly alter the international spread of Zika virus”.
The Olympic Games should be postponed or moved “in the name of public health” over the Zika outbreak in Brazil, more than 100 prominent doctors and professors said in an open letter to the WHO.
The Olympics are scheduled from August 5-21. More than 500,000 people are expected to travel to Brazil from around the world.
“We make this call despite the widespread fatalism that the Rio 2016 Games are inevitable or ‘too big to fail,'” the writers said on Friday in the letter addressed to WHO Director-General Margaret Chan.
“Our greater concern is for global health. The Brazilian strain of Zika virus harms health in ways that science has not observed before.”
The WHO noted that Brazil has been the epicentre of the virus and one of almost 60 countries that have reported continuing transmission of Zika by mosquitoes, CNN reported.
“People continue to travel between these countries and territories for a variety of reasons. The best way to reduce risk of disease is to follow public health travel advice,” the WHO said.
The International Olympic Committee (IOC) has said it has no plans to cancel or postpone the Games.
The officials in the letter stated the Zika virus has “more serious medical consequences than previously known” and has worsened in the Rio area despite widespread mosquito treatment programmes.
“It is unethical to run the risk,” the letter said, adding “It is therefore imperative that WHO conduct a fresh, evidence-based assessment of Zika and the Games, and its recommendations for travellers.”
A team of researchers led by Indian-origin scientists have discovered that the deadly Zika virus can infect and replicate in immune cells from the placenta, without killing them.
According to the researchers, little was known about how the virus was replicating in placenta and in what cell type.
The finding showed that Zika virus could infect Hofbauer cells — placental macrophages — in cell culture.
Hofbauer cells are foetally derived, in contrast with other immune cells found in the placenta called decidual macrophages, which are maternally derived.
They are thought to be more tolerant and less prone to inflammatory responses than other immune cells, the researchers said.
However, signs of antiviral and inflammatory responses were detected in infected Hofbauer cells.
“Host genetics and non-viral factors, including nutrition and microbiota, as well as timing may be influencing infectivity,”
Also, the level of viral replication was found different from donor to donor, hinting that some women’s placentae may be more susceptible to viral infection than others.
“Not every pregnant woman who is infected by Zika transmits the virus to her foetus,”
In addition, the virus could infect another type of placental cell, called cytotrophoblasts, but only after a couple days delay and not as readily.
The study, published in the journal Cell Host & Microbe, may explain how the virus can pass through the placenta of a pregnant woman, on its way to infect developing brain cells in her foetus.
“A better understanding of these factors could allow the design of preventive measures, and eventually antiviral therapies,”