On one hand, we have the WHO Statement on April 1st:
“The diagnosis of microcephaly was made at 22 weeks and one day of pregnancy on 10 March. On 17 March, the foetus’s samples were collected and tested at the Centre Hospitalier Universitaire of Martinique in Fort-de-France: both amniotic fluid and foetal blood samples resulted positive for Zika virus infection by polymerase chain reaction (PCR). On 22 March, the National Reference Center for arboviruses confirmed the infection with Zika virus.”
“On 7 December, the patient’s mother was sampled and a serology test confirmed infection with Flavivirus and alphavirus. A second serology test, which was conducted on 7 January, showed IgG antibodies against flavivirus and chikungunya virus as well as IgM antibodies against Zika virus. A third serology test, which was conducted on 11 February, confirmed once again the presence of IgG antibodies against flavivirus and chikungunya virus. These tests provide evidence that the mother was positive for Zika virus infection. A medical termination of the pregnancy was recommended to the mother.”
This statement is more focusing on clues which refer to Zika virus as causing microcephaly during the first quarterly than other critical information reported such as:
- Other viral infections tested positive in December 7th 2015:
- Flavivirus: might be Dengue (not named)
- Alphavirus: might be Chikungunya (not named)
- Date of arrival of Zika virus in Martinique: first cases reported early January 2016
- Tested positive for Zika virus on January 7th
On the other hand, we observe first:
- co-infection by both Dengue and Chikungunya,
- followed a couple of weeks later by Zika virus infection during the Q1 and just at the beginning of the Zika virus outbreak on going in Martinique.
- Zika virus found in amniotic fluid and foetus blood;
- Foetus diagnosed with microcephaly on March 10th 2016.
“It shows that a foetus can be PCR-positive for Zika virus months after the initial infection of the mother. Furthermore, this report provides additional evidence that infection with Zika virus early in pregnancy could be associated with an increased risk of microcephaly.”
At the end of the day, do we gather enough evidence to declare that this microcephaly is linked to Zika virus or may we address the key role of co-infection with Dengue and/or Chikungunya?
Yes Zika virus is involved in microcephaly but does it play alone or by co-acting with other risk factors?
Here are some lessons learned from the Martinique microcephaly case.