Tuesday, March 22, 2016

Zika infection- Updates


The most happening news in microbiology is currently "Zika Virus". I have previously blogged about Zika (Link). A lot of new studies have been published on Zika in past month. The scientific interest and public concern over the current spread is far too high. Most Journals are fast tracking publications on Zika and majority of the publications on Zika has been made open access. I'm not able to get a clear recent statistics of the declared outbreak. But the current scenario is far more interested in understanding if Zika is really Neuro-invasive.

Photo 1: Zika virus (green) infects
human neural progenitors and
leads to cell death (red). Source
How far is the evidence that Zika is Neuro-invasive? As mentioned in my earlier post, finding of ZKV genome in brain tissue in foetal brain sample is considered as very convincing. A case report of 81 year old man who developed meningoencephalitis (Link) and 15 year old girl in Guadeloupe who developed left hemiparesis (Link) are examples of laboratory confirmed ZKV neuroinfection. In a recent publication 2 cases of GBS was described with ZKV viruria (virus in urine sample). At least in laboratory conditions, it has been shown that ZKV infects human cortical neural progenitors. Neural progenitor cells are a kind of blast cells that give rise to the brain cells. Ability to infect is a positive indication that ZKV can infect brain cells. A large number of labs with experience in handling flavivirus are working on understanding Zika biology. Interestingly, one group is publishing their work on primate model on a real time basis.

The current problems for studying Zika is a need for a non primate animal model and some specific antivirals. Im specifying non primate model because higher animals are difficult to work with and has a lot of regulatory hurdles. Mouse or rat model would be ideal. Searching through latest publications, I found that a group has published an article in pre print. They studied ZIKV infection in type-I interferon receptor deficient (A129) mice and the parent strain (129Sv/Ev). They indicate that A129 mice as being highly susceptible to ZIKV and thus a suitable small animal model. In addition I also found a second article claiming that viral polymerase inhibitor 7-deaza-2'-C-methyladenosine (7DMA) efficiently inhibits ZKV replication.

WHO is shelling out an estimated $7.1m which will be dedicated to ramping up surveillance efforts to provide more accurate information about Zika virus disease, neurologic syndromes, and congenital malformation. The situation is just like Ebola 2014 outbreak. Caught off guard with almost no basic research and community is desperately asking for scientific help.

ResearchBlogging.orgStuart D Dowall, Victoria A Graham, Emma Rayner, Barry Atkinson, Graham Hall, Robert J Watson, AndrewBosworth, Laura C Bonney, Samantha Kitchen, Roger Hewson. A susceptible mouse model for Zika virus infection doi: http://biorxiv.org/content/early/2016/03/04/042358

Joanna Zmurko, Rafael E Marques, Dominique Schols, Erik Verbeken, Suzanne J.F. Kaptein, Johan Neyts. The viral polymerase inhibitor 7-deaza-2'-C-methyladenosine is a potent inhibitor of in 1 vitro Zika virus replication and delays disease progression in a robust mouse infection model. doi: http://biorxiv.org/content/early/2016/03/01/041905

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