noun Zi·ka virus \ˈzē-kə-\
A virus transmitted by mosquitoes which typically causes mild infection (fever, rash, joint pain) in humans. The Zika virus is a flavivirus transmitted by mosquitoes of the species Aedes aegypti.
The World Health Organisation (WHO) has declared Zika virus a global health emergency; they’ve now launched a global prevention and control strategy in order to try and provide a cohesive action plan for research, response and evidence dissemination regarding potential treatments. Anxiety surrounds the Rio Olympics beginning in August to such an extent that the Australian Olympic Committee will be providing their athletes with anti-Zika virus condoms which provide not only a physical barrier, but a lubricant laden with antivirals too.
So why is everyone so worried about Zika?
Initially you may think that so-called Zika fever is no big deal – symptoms are akin to those we see with mild flu so what’s all the fuss about? Zika is different; if you’re pregnant or thinking of getting pregnant any time soon, it’s cause for concern. Sexual transmission of Zika virus is possible, and there is now scientific consensus that Zika is capable of causing an increase in microcephaly (unusually small heads) and Guillain-Barré syndrome (a neurological disorder that can lead to paralysis and in some cases death) in babies born to infected mothers. The problem of Zika is growing and we need to get to work to stop it.
That all sounds pretty terrifying, but how can we stop it?
In very basic terms we need to do three things:
1. Get better at diagnosis
2. Get better at treatment
3. Get better at prevention
Sounds simple, right? Not quite. Zika’s tricky to deal with because it’s main transmission route is through mosquitos – if you’ve ever tried to stop one from biting you, you’ll know they’ll be nibbling away and sucking your blood before you’ve even realised they’re there.
How can CRISPR help?
We know Zika is a nightmare and we’re not great at dealing with it, so how can CRISPR technology step in and (begin trying to) save the day? CRISPR can help us do 2 of those 3 things I said we needed to do to stop Zika – it’s a win, win!
Symptoms of Zika can be easily mistaken for a particularly aggressive common cold, the flu or one of those ‘bugs’ that goes around and fades out after a few days. If we can diagnose the virus effectively, we can prevent it spreading to expectant mothers.
Researchers at Harvard University have developed a low-cost and super quick diagnostic tool that screens patients’ blood, urine or saliva for specific strains of the virus. CRISPR/Cas9 is central to the third part of this diagnostic sandwich; sequence recognition. Once Zika has been detected the sample gets mixed up into a CRISPR/Cas9 cocktail which is used to wet a set of colour-changing paper discs, the paper then changes colour depending on which strain of Zika is present. Read the full press release from the Wyss Institute at Harvard here.
Better than diagnosis is prevention. CRISPR technology gives us the potential to engineer mosquitoes that are resistant to infection by Zika, thereby preventing virus transmission altogether. The WHO is actively encouraging scientists to genetically engineer mosquitoes to combat the virus – that’s a Big Deal and means that scientists and researchers are significantly more likely to focus their efforts on this work. CRISPR/Cas9 has already been used to engineer mosquitos that are resistant to malaria (take a look here), and it looks like Zika could be next on CRISPR’s target list.
So the plan would be to send in guide RNA that targets the female gene (it’s the ladies that are causing all the issues here, male mosquitoes don’t bite), and replace it with the male gene using Cas9. Allowing CRISPR to integrate this male gene into a female mosquito’s genome ensures that the eggs she lays will produce male mosquitoes, rather than their blood-sucking female counterparts. This method isn’t being used just yet, scientists still need to do some work looking at how these engineered mosquitos might react in the wild, how they’d affect wider populations and if they would ultimately have a detrimental impact, it would also be good if we could work out how to undo a CRISPR edit – so there’s next week’s to do list for you if you’re short on work!
Zika virus is reaching new heights in its potential to threaten global health, it’s spreading and we can expect to see further transmission as people flock to Rio this summer. CRISPR technology offers us a method of fighting Zika through use of precisely targeted genome editing.
Ready to use CRISPR to do battle with Zika? Hop on over to our website and order your #CRISPRevolution EZ RNA kit today and start editing!
Want to find out more and join the #CRISPRevolution? Stay informed by subscribing to our mailing list (scroll right to the bottom of this page).