In 2016-2017, 68 women in Southern Vietnam had confirmed Zika virus (ZIKV) infection during pregnancy. Researchers from the Epidemiology of Emerging Diseases team, led by Arnaud Fontanet at the Institut Pasteur (Paris), in collaboration with Institut Pasteur in Ho Chi Minh City, have reported the virological and epidemiological outcomes of these infections. Results to be read in The Lancet Regional Health – Western Pacific. They emphasize the need to maintain epidemiological surveillance for Zika virus infection in the South East Asia region.
Following the Zika virus (ZIKV) epidemic across the Americas (2015- 2016) which resulted in large outbreaks in several regions of the world, epidemiological surveillance for ZIKV infection was enhanced in Southern Vietnam. Between 2016 and 2017, 68 pregnant women had ZIKV infection confirmed by polymerase chain reaction technique (RT-PCR) performed at the Institut Pasteur of Ho Chi Minh City.
ZIKV is transmitted by mosquitoes and most people who are infected do not experience symptoms. For those who do experience symptoms, they are generally mild and include fever, rash, muscle or joint pain. However, ZIKV infection during pregnancy can cause microcephaly in the fetus and other fetal malformations.
In collaboration with the Institut Pasteur of Ho Chi Minh City, the Epidemiology of Emerging Diseases team conducted a multidisciplinary investigation during pregnancy in women infected by ZIKV. The team collected clinical and epidemiological information from the women, as well as from their children. This included information from medical records, blood tests, as well as personal data (age, lifestyle factors etc).
Through genomic sequencing and phylogenetic analysis on the blood samples collected from the pregnant women, conducted in collaboration with the National Reference Centre for Arboviruses in Marseille, France, Arnaud Fontanet’s team has been able to identify a clade within the ZIKV Asian lineage implicated in the infections among pregnant women, in other words, a group of viruses sharing the same viral origin. RNA sequence analysis suggests that the clade was likely introduced to Vietnam between October 2004 and January 2011, prior to the epidemics in French Polynesia and the Americas.
The research group has also been able to describe adverse pregnancy outcomes, including fetal abnormalities which are consistent with the ZIKV-related microcephaly or fetal demise. These adverse pregnancy outcomes have not been widely described with Asian lineage of ZIKV prior to the epidemics in French Polynesia and the Americas. Finally, they have also been able to show the persistence of anti-ZIKV antibodies in the women beyond three years post-infectio
This study improves the understanding of the relative pathogenicity of the Asian lineage of ZIKV. It highlights the need to maintain epidemiological surveillance for ZIKV infection, particularly among pregnant women in South East Asia.
Maternal and neonatal outcomes related to Zika virus in pregnant women in Southern Vietnam: an epidemiological and virological prospective analysis
Authors: Rebecca Grant, Thao Thi Thanh Nguyen, Manh Huy Dao, Hang Thi Thu Pham, Géraldine Piorkowski, Tai Doan Tan Pham, Thang Minh Cao, Loan Thi Kim Huynh, Quan Hoang Nguyen, Linh Dang Khanh Vien, Frédéric Lemoine, Anna Zhukova, Dao Thi Nhu Hoang, Hung Thanh Nguyen, Nhu Tuan Tran, Lien Bich Le, Minh Nguyen Quang Ngo, Thai Chau Tran, Nhan Nguyen Thanh Le, Minh Ngoc Nguyen, Hai Thanh Pham, Tuyet Thi Diem Hoang, Thach Van Dang, Anh Thi Vu, Quyen Ngoc Truc Nguyen, Xavier de Lamballerie, Quang Duy Pham, Quang Chan Luong, Arnaud Fontanet
Journal: The Lancet Regional Health – Western Pacific