Skip to 0 minutes and 12 seconds So there are two types of tests that we could use for Zika infection right now – each one has its advantages and disadvantages. The test to detect virus requires sophisticated equipment, require trained personnel and are expensive, but they are highly accurate and can definitely give us a diagnosis of Zika. Now the antibody based tests are easier to do, cheaper, and can the results can be available in 15 minutes. The problem with that is that antibodies to Zika can be cross reactive with other pathogens, like dengue and yellow fever, and so it’s very difficult to tell from an antibody response whether you definitely have Zika or was it just a cross reactivity with dengue.
Skip to 1 minute and 3 seconds So if we have a more cheaper, more accessible
Skip to 1 minute and 9 seconds test to detect the virus, then it could be used to detect infection early in patients, and identify them definitively as a Zika infection and then start in an outbreak situation you could start interventions right away to prevent transmission, et cetera, putting in vector management measures et cetera. The other thing that better diagnostics would allow us to do, for example, better antibody tests that are more specific for Zika would allow us to do population based studies to understand the epidemiology of a Zika infection, how extensive the outbreak is, and what are the associations with complications, such as microcephaly. And so these diagnostics we hope will be available soon.
Skip to 2 minutes and 6 seconds I think the problem with Zika is that because it’s similar to, for example, dengue viruses, most likely it’s going to end up in all of those areas of the world where dengue virus is common, which is a third of the world and
Skip to 2 minutes and 20 seconds that could become a big problem. We’ve seen similar viruses like chikungunya virus that started small and has spread worldwide, and I imagine that Zika has the potential at least to go along those lines.
Skip to 2 minutes and 37 seconds We therefore need to think about how the virus gets introduced and maybe if we can target those we can maybe slow and and prevent some of those transmissions from occurring. I think the world needs to be vigilant for those and that means detection, diagnosis, surveillance, and hopefully targeted interventions to really get to grips with those and this is all areas which we don’t have right now, but we should plan for in the future. Zika does have these peculiarities of being found in other samples, such as urine and semen, and of course we are worried about the transplacental transmission of the virus as well.
Skip to 3 minutes and 23 seconds So these different conditions that clearly need to be researched so that we can understand how important they are and what causes that. For example, these transmissions occur when there’s a lot of virus in the blood, not everybody seems to have these transmissions and maybe only those that have high viral titer may end up with these transmissions; and then perhaps we might think about how these high titers are generated in some people and not others. And you know there’s potential there for the antibody enhancement or something else that might lead to these conditions and maybe by understanding that we can obviously try and prevent it.
Skip to 4 minutes and 6 seconds And of course I think for the mosquito transmissions, we also want to understand where those might be, and in my work using that the viral sequencing, were trying to find the hot spots of transmissions where we know there’s been a lot of activity of viral transmissions. And if that’s the case, maybe we can target some intervention to prevent those– in a resource limited area you want to make sure you take advantage of the small amount of resources that you have, and we can use the viral sequencing to help us with that.
Skip to 4 minutes and 43 seconds Zika virus is a new virus, but because it’s a little bit related to other viruses, such as hepatitis C and dengue virus, there has actually been a fair amount of research to see whether we can find new drugs to target these viruses. Hepatitis C has had quite some success, and it looks like there is genuinely a new treatment that has come onto the market recently. For dengue virus, we are still evaluating those it hasn’t been, well there’s been no introduction just yet, but I’m actually doing current research investigating them, and we hope that that might be the case in the future.
Skip to 5 minutes and 22 seconds So these drugs then, if they work against hepatitis C and dengue, maybe they work against Zika virus as well, and I’m sure quite a large number of groups are working on this. The next question if we can find a drug that works is how best to use it and right now we’re thinking that treating the active disease during that small window of time when it’s difficult to recognize that they have the current infection might be difficult, and so an alternative might be for a prophylactic use.
Skip to 5 minutes and 55 seconds Maybe if you can take the drug for two or three months you might be able to prevent transmission during that time period and that might be important for pregnant mothers or other people that need to avoid the virus infections. So that’s an area I think that we could contribute to as a community and maybe we can work out how best to use any potential new drugs.
Gaps in our knowledge: virology and testing
In the second of two steps reflecting upon the need for better quality studies, Professor Rosanna Peeling debates the pros and cons of the diagnostic tests we currently have to diagnose Zika. How and why are cheaper, more accessible tests needed to detect the virus, and how could they help to inform and control the current outbreak?
Professor Martin Hibberd then considers how the virus is transmitted, highlighting why alternative, non-mosquito transmission routes must be researched in order to prevent further infections. He explains why finding ‘hot spots’ of mosquito transmission could help us to direct interventions efficiently with limited resources, and whether new drugs could target Zika and other similar diseases. If we find a drug that works, how should it be used?
In these two steps we have thought about further research in entomology, epidemiology, virology, and diagnostic testing. In which other areas do you think we could expand our understanding with high quality research studies?
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