On 24 March 2016, the National IHR Focal Point for France notified PAHO/WHO of a fetus with concomitant microcephaly and Zika virus infection in Martinique.

Martinique Image/M.Minderhoud

The diagnosis of microcephaly was made at 22 weeks and one day of pregnancy on 10 March. On 17 March, the fetus’s samples were collected and tested at the Centre Hospitalier Universitaire of Martinique in Fort-de-France: both amniotic fluid and fetal 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 is the first case of Zika virus infection detected in a fetus with microcephaly in Martinique. This report is important because it offers a prospective documentation of Zika virus infection in a mother and a fetus. The information presented here allows the estimation of the stages of pregnancy at which the mother and the fetus became infected. It shows that a fetus 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. Further investigations, however, will be required to fully comprehend the role of Zika virus infection in the development of congenital abnormalities, such as microcephaly, and to establish any causative links.