508 confirmed microcephaly diagnoses in Brazil...let's just say they're all Zika virus related because...belief?

This comes from the 13th Brazil Ministry of Health's (MOH) Health Portal epidemiological reports on microcephaly [1] which spans from when microcephaly diagnoses began sometime during 2015, to the 13th of February 2016.[2]

With the aid of Google translate, the report states that 5,820 suspected diagnoses have been logged to 13FEB2016 of which 1,345 (25.5%) have been finalised as:

• 508 confirmed (37.7% of the finalised suspects)
• 837 discarded  (62.2%)
• 60.1% were recorded in 2015 and 39.9% are from 2016 so far
• The previous MOH report noted that 41 of the then 462 confirmed microcephaly diagnoses were somehow (mum or foetus or baby?) laboratory confirmed as being aligned with a Zika virus infection [4]

Geographic distribution of 508 confirmed microcephaly cases from 2015 and 2016.
Data and graphic from the Brazil Ministry of Health.[2]

But what absolutely flummoxes me is this translated text (highlights added by me) from the end of the report,[2] found in a big red "Heads up" box. In particular that highlighted in yellow:

The Ministry of Health believes that there was infection zika virus mostly mothers who had babies whose final diagnosis was "microcephaly and / or changes in the central nervous system, suggestive of infection congenital ". 

Therefore clarifies that from this Report Epidemiological No. 13 concerning the epidemiological week 06, 2016, will disclose these confirmed cases, without specifying the laboratory diagnosis to Zika virus, because these data do not adequately represent the number of observed cases (magnitude).

Furthermore, from that moment, consider that all confirmed cases are related to congenital infection Zika virus. 

All cases are individually assessed and submitted to a laboratory set of diagnostic tests and imaging (ex .: ultrasound transfontanellar etc.). A very small proportion of these cases, after monitoring and Specific analysis is confirmed for other causes, but they are so few children that does not change the assessment the trend (increase or decrease) the number of cases (magnitude). It is important to inform that the Ministry of Health participates in and supports the entire national effort directly and international for better understanding of this new disease and that every effort is being made to improve diagnostic methods and strengthen assistance to children and families affected.

I'm presuming this is because the MOH cannot get any samples from earlier diagnoses and thus cannot test them. Or perhaps they were negative and it has a "feeling" that they should have been positive. 

No idea. 

I have felt nothing but unease about the way Zikacephaly has been settled on via a process of accusation, summary judgement and instant public conviction during 2016 - via instances in both the media and the scientific literature. 

I'm now in complete disbelief that a national MOH is relying on a 'belief' without further data or discussion, to officially communicate a message about the cause of a severe disease. 

Why not rely on a careful analysis of extensive testing data? Do such data exist? Are they bottled up in the publication pipeline? Why not employ a more reasoned public engagement strategy whereby careful and balanced description of the the risks and all the knowledge gaps, is communicated to a rightfully worried community? And to the world, because no outbreak or epidemic affects the host country in isolation any more. 

The battle to cull the mosquito vector and avoid bites was under way quickly, so why the need to point the finger so urgently when nothing additional can be done right now anyway? So we can get a vaccine underway? What if...heretical at this point I know, but what if Zika virus is not the cause of the surge in microcephaly cases? Gasp!! What a gigantic waste of resources and public faith in science we will have burned through because-belief?

Wouldn't it be better to undertake a more careful investigation and analysis before putting any more eggs in the single, lonely Zika virus basket?  

Just to be clear, I don't for second discount that Zika virus could be the cause of microcephaly - but I'm not just going to put that in a text book until the studies have been done. Those studies have not been done yet and neither have any studies been done that discount anything. 

As we can see in red above, there are clearly other causes of microcephaly being found in Brazil. Presumably these are some of the better known causes like in utero or at birth infections by the Toxoplasma gondii parasites, Treponema pallidum bacteria, rubella virus, herpes simplex virus, cytomegalovirus and human immunodeficiency virus or due to chemical exposures in the mum, including to arsenic, mercury, alcohol, radiation, and smoking or perhaps genetic abnormalities including Down syndrome or even severe malnutrition during development. Even if in small numbers-one or more of those things (which were not detailed by the MOH report) are clearly present and though to be acting. 

Everything is still on the table as a cause of microcephaly in the north east of Brazil-as it always has been since probably much earlier than October of 2015.[3]

References...

1. http://portalsaude.saude.gov.br/index.php/o-ministerio/principal/leia-mais-o-ministerio/197-secretaria-svs/20799-microcefalia
2. http://portalsaude.saude.gov.br/images/pdf/2016/fevereiro/17/coes-microcefalia-inf-epi-13-se06-2016.pdf
3. http://www.who.int/csr/don/20-november-2015-microcephaly/en/
4. http://portalsaude.saude.gov.br/images/pdf/2016/fevereiro/12/COES-Microcefalias-Informe-Epidemiologico-12-SE-05-2016-12fev2016-13h30.pdf