From Z to A - ZIKA VIRUS.

[Doc Alan]

Zika Virus ( ZIKV ) is the latest unexpected " arrival " in the Americas of an " arbovirus " - transmitted by " arthropods ", like mosquitoes. Only a small number of these viruses cause medically important illness, especially dengue, and also chikungunya ( each in other Forum threads ).


ZIKV was first isolated from a monkey in the Zika forest of Uganda about 70 years ago. Until recently it wasn’t thought to be much of a threat - only a fifth of infected people fall ill, usually with mild FAR ( Fever, Arthralgia = joint pains, and Rash ).


The interest - and worry - is that it MAY cause birth defects ( such as microcephaly = small head with brain damage ) and rarely nervous system problems ( including paralysis ) in adults.


There is now a ZIKV epidemic, and a public health emergency, in Brazil ( estimates between half a million to over 1.3 million cases ) - where the Olympic Games are due to be held in August this year - also involving elsewhere in South America, Central America, and the Caribbean. Urban crowding, international travel, and other human behaviour have probably contributed.


ZIKV is transmitted by the bite of an infected female mosquito - Aedes aegypti most commonly. This mosquito is not present in the UK ( too cold ),but three cases have this month been diagnosed in travellers from Colombia, Suriname, and Guyana. It’s not spread from person to person.


There have been recent epidemics in Micronesia and French Polynesia, but only isolated cases in the Philippines and elsewhere in South East Asia.


Once again, as with Ebola, a virus infection has emerged unexpectedly:doh. This time - NO specific treatment ( just supportive nursing care and relief of symptoms ) ; NO vaccines ( they will be developed but who to vaccinate and at what cost ? ) ; even diagnosis is difficult and expensive.


Attacking disease-carrying mosquitoes and personal protection ( such as repellent use ) are therefore all the more important. Aedes mosquitoes, which also transmit dengue, mainly bite during the day ( unlike those transmitting malaria ). ZIKV infection is mild in most cases, but obviously of concern - especially if pregnant in South and Central America. It's not yet fully understood.

[johncar54]

Thanks Doc,, very interesting post

[Arthur Little]

Thank you, indeed, Alan ... for your detailed and most welcome explanation relating to Brazil's outbreak of the viral infection known as *ZIKA - trasmitted through mosquito bites - and, of course, *its potentially~devastating effect on pregnant women, as televised in
a special report from Rio de Janeiro on last night's Late News Bulletin.

:yeahthat: was the first I'd heard of this horrific disease, and I hope and :pray: its spread can be brought under control by the Brazillian authorities ahead of this year's Olympics.

[Doc Alan]

Thanks in turn for your responses, John and Arthur :xxgrinning--00xx3:.

[Michael Parnham]

Another interesting and educational Post Alan, thank you!:xxgrinning--00xx3:

[Doc Alan]

Another interesting and educational Post Alan, thank you!:xxgrinning--00xx3:

Thank you in turn for your response, Michael :xxgrinning--00xx3:.


It's likely that ZIKV infection will involve all countries in the Americas, apart from Canada and Chile ; indeed all countries where Aedes mosquitoes are found, including the Philippines, may be at risk of epidemic infections. It's unlikely a vaccine could be available for at least three years.


Obviously this is an evolving situation, but one which I judged worthwhile raising as a Forum topic. The Zika outbreak comes hard on the heels of the Ebola epidemic in West Africa, showing - again - how little-understood diseases can emerge as global threats.

[Michael Parnham]

Thank you in turn for your response, Michael :xxgrinning--00xx3:.


It's likely that ZIKV infection will involve all countries in the Americas, apart from Canada and Chile ; indeed all countries where Aedes mosquitoes are found, including the Philippines, may be at risk of epidemic infections. It's unlikely a vaccine could be available for at least three years.


Obviously this is an evolving situation, but one which I judged worthwhile raising as a Forum topic. The Zika outbreak comes hard on the heels of the Ebola epidemic in West Africa, showing - again - how little-understood diseases can emerge as global threats.

You never post anything that is uninteresting Alan, I enjoy reading all your posts :xxgrinning--00xx3:

[Terpe]

The Zika Virus is an almost daily news topic here just now.

[fred]

I just read they are planning to drop in millions of genetically modified Mozzies.. I just hope they know what they are doing..We could well end up with a mosquito product that is much worse.

[Doc Alan]

Genetically modified ( GM ) mosquitoes have been produced by a British company recently taken over by one based in USA. GM males carry a gene that stops their offspring developing properly - dying before they can reproduce and become carriers of disease. Such mosquitoes have already been approved for use in Brazil - and millions previously trialled in Brazil, the Cayman Islands, Panama and Malaysia. ( Another form of GM mosquitoes may resist the parasites causing diseases.) The USA Food and Drug Administration ( FDA ) has yet to produce an " environmental impact " report.


Of course there are downsides to removing mosquitoes - there may be effects on the food chain for animals ; any surviving GM offspring could be more aggressive and dangerous. There seems no realistic chance of ever killing an entire species of mosquitoes in this way.


Now World Health Organization ( WHO ) is worried that three to four million people may be affected in the Americas this year. A WHO " Zika emergency team " will meet next week to decide whether it should be treated as a global emergency, like Ebola. WHO doesn’t want to be accused ( again ) of acting slowly. Next month’s Carnival, and August’s Olympic Games, add urgency to the issue.


ALL countries already affected, and those with mosquitoes already carrying other diseases, need to be prepared by :-

1.Vector ( carrier ) control ( such as removing water-containing sources; using fish that feed on larvae ; insecticide spraying; GM mosquitoes ).

2.SENSIBLE risk communication ( health information, such as use of repellents and appropriate clothing ; travel advice, especially for pregnant women ).

3.Careful testing and observing for associated diseases ( association NOT necessarily causation ).

4.Best treatment of the 1/5 cases with symptoms - NO antiviral drugs yet available.

5.Speeding up research for effective VACCINES.


Once again, the situation is evolving - posts so far here will soon be out of date ; this is also not a medical Forum but I've updated members as best I can !

[fred]

1.Vector ( carrier ) control ( such as removing water-containing sources; using fish that feed on larvae ; insecticide spraying; GM mosquitoes ).

I`ll tell you this Doc...about 4 years ago we had 4 months without rain...As I have no neighbors there is little chance of standing water anywhere nearby.. I still got bitten every night whilst outside..
On occasion I sit and wonder just where the hell they come from in those conditions?
These days I have a fish pond full of guppies that I do not feed and I know for a fact that the fish are eating the eggs and the wrigglers..
Insecticides and off lotion is expensive for locals and they dont use it for that reason.

[Terpe]

The first few months I was here those darned mozzies were a pain in the ass every night.
These days I don't get bothered at all.................don't know why. Haven't been bitten for as long as I can remember.
Bring on the San Mig I say :biggrin:

[Doc Alan]

Thank you Peter and Fred for interesting responses :smile:.


Zika continues to feature daily in the news here, the Americas and elsewhere in the world.


The main, perhaps only, transmission route for Zika is via mosquitoes which pick up the virus from infected people and pass it on by biting others.


Clearly, dealing with mosquitoes which carry Zika would also help against not only other diseases carried by these ( Aedes ) - such as dengue, chikungunya and yellow fever - but also others ( Anopheles ) which carry malaria.


This outbreak has triggered a debate about birth control, sex education and abortion, which may outlast the outbreak itself. As in the Philippines, it’s claimed over half of pregnancies in Latin America and the Caribbean are unintended. Of more immediate help is distribution of insect repellent to 400,000 expectant mothers in Brazil.


There is uncertainty - not only about the association between Zika and microcephaly ( and other nervous system abnormalities ), but also just how much the apparent rise in cases is REAL. An " awareness " effect is recognised - there has been an intense search for cases which may otherwise have been missed, with misdiagnoses. It’s thought - by some - that the reported numbers of microcephaly are MORE than any true increase. This is because if the diagnosis is only made by head size ( circumference ), it may include healthy children within the normal range - brain size must also be measured. Only careful studies over time will make the true situation clear.


Meantime it’s sensible, for pregnant women especially, to be cautious and protect against bites - " let us spray and not panic " :xxgrinning--00xx3:

[Doc Alan]

As expected, World Health Organization ( WHO ) has this week declared the Zika outbreak a " Public Health Emergency of International Concern " - as they did with Ebola. This is because of the association between Zika infection and a rise in detected cases of congenital malformations and neurological abnormalities. Other areas of concern were the lack of :- vaccines ; rapid and reliable diagnostic tests ; and lack of population immunity in newly affected countries.


WHO’s intention is to coordinate a global effort to understand, prevent, diagnose, and treat Zika virus infection. WHO found " no public health justification for restrictions on travel or trade to prevent the spread of the virus " ( Olympic Games expected to go ahead ). Pregnant women in, or travelling to, affected areas need up to date advice from their physicians.


The Philippines Department of Health in a press release simplyreminded the public to " use self-protection measures, seek early consultation for fever lasting more than 2 days, and search and destroy mosquito breeding places ". The last documented case in the country was a 15 years old boy in Cebu City in 2012, who recovered fully.


England’s Chief Medical Officer told MPs on the House of Commons Science and Technology committee that " there is no risk to people in Britain now, nor in the future. There is a risk to our people travelling to affected areas " and " Public Health England has given travel advice to pregnant women and those trying to get pregnant that they should think carefully before travelling to the affected areas and that anyone going there should protect themselves from mosquito bites ".


No doubt regular updates will continue to be widely available on news and health care media around the world.

[fred]

Saw on the news today that the US has a case of this disease being spread by sexual contact.
If this is 100% confirmed then this thing could escalate much faster than expected.

http://www.reuters.com/article/us-health-zika-idUSKCN0VB145

[Doc Alan]

Saw on the news today that the US has a case of this disease being spread by sexual contact.
If this is 100% confirmed then this thing could escalate much faster than expected.



Obviously this case ( not the first ) raises more questions about Zika virus, which will take time to answer accurately. We don’t know how commonly sexual transmission may occur and how long Zika virus may survive in semen.


However, since the evidence so far is that Zika is spread by mosquitoes in the vast majority of cases, the aims are still - as already stated - to target mosquitoes and protect from their bites, in addition to developing vaccine(s), better diagnosis, and specific treatment.

Unlike Ebola or HIV, Zika infections are short, mild in most cases, and appear to pose a significant threat only in pregnancy.

[Rosie1958]

Some really interesting information in this thread, thanks for sharing Doc Alan :xxgrinning--00xx3:

[Doc Alan]

What’s new since the last update ?


* Good evidence virus CAN be transmitted from mother to fetus during pregnancy ; frequency of and risk factors for transmission unknown.


* Sexual transmission to partners of returning male travellers who acquired virus infection abroad HAS been reported ; risk factors for and duration of risk of sexual transmission not known.


* Transmission through blood transfusion not ( yet ) reported but thought likely.


* Incubation period unknown, thought generally to be less than a week.


* May rarely be serious complications affecting the adult nervous system.


* Still don’t know full spectrum of fetal outcomes resulting from infection. Over-reporting and misdiagnosis has probably inflated the numbers of microcephaly reported ( well over 4000, mostly in Brazil ).


* Diagnosis - detection of viral nucleic acid and then antibodies in blood. Clinical symptoms usually mild and laboratory diagnosis not always available, so we don’t know true numbers of cases, but informed opinion is that millions of virus infections may be expected.


* Treatment for uncomplicated infections focuses on symptoms. NO vaccine exists - they are being developed either as “ inactivated “ vaccines based on killed viruses, or “ live attenuated “ ( weakened ) viruses - but probably unavailable for at least a couple of years. NO specific drugs yet available.


* Prevention and control measures centre on avoiding mosquito bites and controlling mosquitoes.


* Still don’t fully understand WHY the virus emerged / increased in the past decade. Increases of dengue and chikungunya - also mosquito spread - suggest common features, such as globalization and urbanization. Viral mutations and lack of immunity in previously unexposed populations are other possibilities.



* Huge and increasing amount of information on this virus. Latest review article in New England Journal of Medicine ( http://bit.ly/1Nuazak ).

[Steve.r]

Interesting update Alan, thanks :xxgrinning--00xx3:

[Doc Alan]

This week Brazil’s Senate voted to impeach the country’s president, Dilma Rousseff, on charges that she manipulated fiscal accounts. While the impeachment trial is being conducted, the vice-president, Michel Temer will take over as president - perhaps serving out the president’s term, if she is convicted.


This is not good news, with the Olympic Games due to start on August 5 and Paralympic Games on September 7 in Rio de Janeiro - together with the Zika virus outbreak.


There are reasons to be optimistic, at least regarding Zika virus :smile:.


The outbreak and excess of microcephaly cases are mostly in the Northeast Region ( Rio is Southeast ).


Dengue virus transmission gave rise to concern during the Brazil FIFA World Cup 2 years ago. However, it took place at a time of year ( Brazil’s winter ) unsuitable for Aedes Aegypti mosquitoes - as will the forthcoming Games.


Athletes and spectators will hopefully spend their time in areas purged of mosquito breeding sites and sprayed with insecticides.



The increase in visitor numbers for the Games may well be balanced out by a relative lack of business travellers and other tourists during this time.


Clearly athletes and visitors need good advice on the risk of Zika virus infection, and other mosquito-borne diseases - with precautions to avoid mosquito bites, contraception for women of child-bearing age, and prevention of sexual transmission.


That’s up to World Health Organization, the International Olympic Committee, and local organizers. The number of new publications on Zika virus has itself gone viral this year ( http://bit.ly/1TbvAnn )!

[Rosie1958]

Thank you for the interesting read and update Doc Alan. I will be going to Vietnam in a few weeks and have recently been notified that there is an outbreak there. Fortunately, I'm no longer of child bearing age but I will still be taking precautions (as I always do) to avoid mosquito bites :xxgrinning--00xx3: