Zika Virus

[Barrister]

Following up on Garbo's link, it says this isn't just Brazil - there has been a spike in CNS malformations in French Polynesia, which wsa hit by Zika about a year earlier than Brazil.

On 24 November 2015, the health authorities of French Polynesia reported an increase from an average of one
reported case annually to 17 cases of CNS malformations in foetuses and infants during 2014–2015. Different CNS
malformations were observed among 12 of the cases and were reported by the health authorities of French
Polynesia as: microcephaly (head circumference <5th percentile), destruction of cerebral structure, cerebellar
hypoplasia, corpus callosum agenesis, and severe ventricular dilatation >10 mm at first trimester. The findings led
to termination of pregnancy in nine instances. The three remaining cases were born at term with normal body
measurements and presented poly-malformations and brains lesions. Cytomegalovirus testing was negative and
karyotype was normal. An unusual increase of brainstem dysfunction was observed during the same period (five
cases with normal magnetic resonance imaging and standard genetic analyses negative). None of the mothers
presented Zika virus infection compatible symptoms. Biological investigations are ongoing. Based on the temporal
correlation of these cases with the Zika outbreaks in French Polynesia, the local health authorities hypothesise that
Zika virus infection may be associated with these abnormalities if mothers are infected during the first or second
trimester of pregnancy [3].

http://ecdc.europa.eu/en/publications/Publications/rapid-risk-assessment-zika-virus-first-update-jan-2016.pdf

[crazy canuck]

Which is pretty much what the expert on the CBC said - that it is likely the virus has mutated. 

[garbon]

Which is pretty much what the expert on the CBC said - that it is likely the virus has mutated. 

Based on the temporal correlation of these cases with the Zika outbreaks in French Polynesia, the local health authorities hypothesise that Zika virus infection may be associated with these abnormalities if mothers are infected during the first or second trimester of pregnancy

Maybe likely means something different to you...

[Fate]

The fact remains that Brazil's prior reporting of microcephaly cases is highly questionable. There is no reason to believe that Brazil is a special snowflake and had a real microcephaly rate 100 times below what is normal for a first world country like the United States until the year 2015.

We're putting an international spotlight on a developing country and applying first world expectations. I argue they simply had shit data in the prior years and now Brazil is likely reaching report rates that are normal for a country their size. In a country of 200 million people and 3 million births there should be about 15,000 cases of microcephaly in a normal year. If Zika is truly increasing the incidence we should see far greater numbers than that... but we're only at 3500.

[crazy canuck]

Which is pretty much what the expert on the CBC said - that it is likely the virus has mutated. 

Based on the temporal correlation of these cases with the Zika outbreaks in French Polynesia, the local health authorities hypothesise that Zika virus infection may be associated with these abnormalities if mothers are infected during the first or second trimester of pregnancy

Maybe likely means something different to you...

Perhaps if you were not in Languish mode you might have realized I was commenting on the bit you quoted from what you linked.  Do you see the similarity?

"I suspect the virus may have changed," says Scott Weaver of the University of Texas in Galveston.

[garbon]

Which is pretty much what the expert on the CBC said - that it is likely the virus has mutated. 

Based on the temporal correlation of these cases with the Zika outbreaks in French Polynesia, the local health authorities hypothesise that Zika virus infection may be associated with these abnormalities if mothers are infected during the first or second trimester of pregnancy

Maybe likely means something different to you...

Perhaps if you were not in Languish mode you might have realized I was commenting on the bit you quoted from what you linked.  Do you see the similarity?

"I suspect the virus may have changed," says Scott Weaver of the University of Texas in Galveston.

Once again it is your summary that I take issue with. I agree that both are similar in that it is possible it might have mutated and thus at fault. Not languish mode to note that's different from your summary as likely to have mutated and is causing this.

[jimmy olsen]

I'm inclined to believe fate. he always provides in depth explanations that make sense, and he doesn't have a track record of being wrong. the only time I remember him being wrong about something medical related was the "this won't cause ebola deaths in the US." and iirc, that was more "well fuck, an accident happened that led to someone actually dying."

doctors aren't like lawyers; the average doctor is usually pretty competent thanks to strict school admission standards.

also

http://www.nytimes.com/interactive/2016/01/16/health/what-is-zika-virus.html?_r=0

Normally, about 150 cases of microcephaly are reported, and Brazil says it is investigating more than 3,500 reported cases.

But reporting of suspected cases commonly rises during health crises.

I am a bit more inclined to accept what the guy who actually studies this has to say over some other guy who is still in training and took a brief period of time out of his busy schedule to think about it.

Hasn't Fate graduated?

[Fate]

Yeah, several years ago. I'm in residency training. Infectious diseases and public health is just a hobby.

I sent an email to one of the principal investigators in Brazil and author of the MMWR CDC report to see what was up with her numbers. Her email is Portugeselish but it was interesting never the less. Bolding is mine.

Dear Dr. [<Fate>]

Thanks for your message.  First of all I think that the US rate of microcephaly as 0.5% refers of microcephaly secondary to any brain damage, because we would expect from the Gauss curve (the bell curve) that, by definition 2.5% of every children would be born neg 2SD. So that explains why there is partly some disagreements in definitions.

Only HC under 2SD is not a definition of MAJOR congenital anomaly. It is only if there is a subjacent brain anomaly.
Many classifications use 3SD below the mean as a cutoff.

So the 150 cases were part of the cut off definition (originally only VISIBLE microcephaly with neurological abnormality was recorded) PLUS a chronic underreport on the birth certificates (from where the data from 2010-2014) was extracted.

After the alert in Pernambuco (NE Brazil), Brazilian government started to register as SUSPECTED cases for epidemiological vigillance all children born with 33 cm or less, or under 1SD. In December, this criterion was reviewed and only children born with 32 cm (2SD) or less  were included as "suspected" . That means that part of the increase is really an artifact of changing definitions. And, of course, better registration of cases. HOWEVER, even before the alert by the MoH and consequently the media, an increase of records of microcephalic babies was observed based on the national birth certificates registry (SINASC)  Acclaration for SINASC: in Brazil, every liveborn certificate has a field to be completed by the doctor/nurse describing if the baby has any congenital anomaly and which one it is. It's largely known that there is an under registration on these certificates.

However, even considering that now we have an overreport, from my personal observation, we have 17 cases of SEVERE microcephaly (that means head circumference below 3SD) born in Ceara state from August-December, 2015.  In Ceara, we have in average of 10,000 births per month - therefore 60,000 births in each semester. 17/60,000 means 2.8/10,000 , which is already on the top of expected for HC under 3SD which is expected to be 1-2/10,000 worldwide.

Moreover, they are not only microcephalic babies - they present brain abnormalities very suggestive of congenital infection AND have a peculiar clinical presentation which is different from other genetic or environmental syndromes known to cause microcephaly. Of course this is only preliminary information and we are collecting and examining more cases to "curate" this number being notified by the MoH.  From the MoH SUSPECT cases, in average, half is excluded due to inaccuracy of head measurments, another clear etiology (genetic or other infection known to produce microcephaly) or children with microcephaly WITHOUT any brain or neurological abnormality.

My personal impression is that THERE IS an augmentation of cases of microcephaly in Brazil, HOWEVER is not that huge as the suspected cases referred to the MoH.  It is not possible yet to evaluate the magnitude of the affected cases but we believe that soon our work which is collaborative with other groups in Brazil. Of course, there are other causes of microcephaly but it would NOT explain a sudden temporal increase in the cases we are seeing. Moreover, as I told you, these 17 cases of SEVERE microcephaly only had ALL tests for other infections, and examination excluding FETAL ALCOHOL SYNDROME, diabetes, genetic disorders. Rubella is erradicated from Brazil, and malnutrition to cause microcephaly should be EXTREME and we don't have many cases of that in Brazil anymore. So there is really a red flag.

I'm willing to discuss any further questions you might have

Lavinia


Lavinia Schuler-Faccini
Presidente - Sociedade Brasileira de Genetica Medica
www.sbgm.org.br

Departamento de Genetica / Universidade Federal do Rio Grande do Sul
Serviço de Genética Médica / Hospital de Clinicas de Porto Alegre
Caixa Postal 15053 - Ag. Campus Agronomia
CEP 91501-970, Porto Alegre, RS - Brazil

I'd argue that simply because they had excluded all other known toxic or infectious causes of microcephaly in those 17 cases, does not mean these cases were caused by Zika virus. I sincerely doubt they did thorough genetic testing of these fetuses (which cause up to 50% of the cases) given the limited resources of the country. She also repeats the claim that severe microcephaly has a worldwide incidence of 1-2 cases per 10,000 while in the US we know this number is really more like 1 in 1,000.

It'll be interesting to see how far the hysteria in the US goes. Rapid development of a vaccine and mass vaccination campaign? Donald Trump proposing a ban on Latin American immigrants/travelers for fear that they have a congenital defect causing virus in their blood?

[LaCroix]

I am a bit more inclined to accept what the guy who actually studies this has to say over some other guy who is still in training and took a brief period of time out of his busy schedule to think about it.

right now it's all speculation. like I said, what fate has said makes sense. it makes a lot more sense than "well, it's possible that a maybe occurred." fate could be wrong, but he's made a much more convincing argument. just like I'd believe a well-made minsky argument over some unknown legal scholar who talks a bunch of BS

[Barrister]

Interesting email Fate.  Thanks for posting.

I guess I have to stick up for Brazil a little bit.  While it is definitely a developing country, it's not some failed state either.  They do have fairly advanced hospitals and doctors.

[katmai]

Fate or CDC? Hmmm....

[celedhring]

Agencies like the CDC have kinda the duty of planning for worst case scenarios, though. I would expect them to react strongly even if the evidence is faint.

[Alcibiades]

Fate or CDC? Hmmm....

CDC, now WHO...or Fate? 

"Zika virus spreading 'explosively', says World Health Organisation"

http://www.theguardian.com/world/2016/jan/28/zika-virus-spreading-explosively-says-world-health-organisation

[Barrister]

Fate or CDC? Hmmm....

CDC, now WHO...or Fate? 

"Zika virus spreading 'explosively', says World Health Organisation"

http://www.theguardian.com/world/2016/jan/28/zika-virus-spreading-explosively-says-world-health-organisation

Well that's a little different.  There's no debate about the fact that Zika is spreading wildly.  It is.  It was first spotted in Brazil in April 2015 and is expected to be spread throughout the Americas by the end of 2016 (except Canada and Chile).

What Fate is questioning is whether Zika is linked to brain defects in newborns.

Butthe symptoms of Zika are really minor.  Most have no symptoms at all.  If you do have symptoms  you get a fever and a rash.

[lustindarkness]

"Zika" sounds like one of those made up names people give their babies to sound more "ethnic".