Infection Hot Topic
Rapid spread of emerging Zika virus in the Pacific area
Version of Record online: 4 AUG 2014
© 2014 The Authors Clinical Microbiology and Infection © 2014 European Society of Clinical Microbiology and Infectious Diseases
Clinical Microbiology and Infection
Volume 20, Issue 10, pages O595–O596, October 2014
How to Cite
Musso, D., Nilles, E. J. and Cao-Lormeau, V.-M. (2014), Rapid spread of emerging Zika virus in the Pacific area. Clinical Microbiology and Infection, 20: O595–O596. doi: 10.1111/1469-0691.12707
- Issue online: 2 DEC 2014
- Version of Record online: 4 AUG 2014
- Accepted manuscript online: 7 JUN 2014 01:21AM EST
Zika virus (ZIKV) is an emerging arthropod-borne virus (arbovirus) belonging to the family Flaviviridae and genus Flavivirus. ZIKV was first isolated from a monkey in the Zika forest of Uganda in 1947 .
Subsequently, sporadic human infections were reported in Africa and Asia. In 2007, the first large documented ZIKV outbreak was reported from Yap State, Federated States of Micronesia . No further transmission was identified in the Pacific until October 2013, when French Polynesia (FP) reported the first cases; a subsequent explosive outbreak resulted in an estimated 28 000 cases seeking medical care (approximately 11% of the population) [3, 4].
Phylogenetic analyses demonstrated that the FP strain was closely related to Cambodia 2010 and Yap State 2007 strains, corroborating previous findings of the expansion of the ZIKV Asian lineage .
During the FP outbreak, most clinical cases presented with mild disease characterized by low-grade fever, maculopapular rash, arthralgia, and conjunctivitis.
In November, a patient presented with Guillain–Barre syndrome (GBS), an autoimmune disease causing acute or subacute flaccid paralysis, 1 week after a confirmed acute ZIKV infection . Subsequent GBS cases were identified, correlating temporally with the ZIKV outbreak. The incidence rate of GBS cases during the ZIKV outbreak was approximately 20-fold higher than expected given the size of the FP population and the established incidence rates of GBS (1–2/100 000 population per year) .
No severe disease resulting from ZIKV infection had been reported prior to the FP outbreak, but previous clinical characterization was based on a limited number of confirmed cases. The recent temporal and spatial association between the FP ZIKV outbreak and the highly unusual GBS cluster is very suspicious, but does not confirm ZIKV as the antigenic stimulus predisposing to this autoimmune disease.
ZIKV is transmitted by the bite of infected mosquitoes, and has been isolated from several Aedes mosquito species , notably Aedes aegypti, which is widespread in the tropics and subtropics, and Aedes albopictus, which is established in many parts of Europe, especially in Mediterranean countries. In FP, Aedes polynesiensis is also suspected to contribute to ZIKV transmission.
Non-vector borne ZIKV transmission through sexual intercourse  and perinatal transmission  has been reported. Given that transfusion-related ZIKV transmission is a potential risk, molecular screening was implemented in FP for blood donors during the outbreak: 2.8% of blood donors, who were asymptomatic at the time of donation, tested positive for acute ZIKV infection .
Following the FP outbreak in late 2013, there were subsequent outbreaks in New Caledonia, the Cook Islands, and Easter Island  (Fig. 1). Because of the typically mild clinical symptoms, limited ZIKV diagnostic capacity, and overlapping clinical features of ZIKV, dengue, and chikungunya, which are also circulating in the Pacific, we believe that ongoing and undetected ZIKV transmission in other Pacific island countries, and potentially beyond, is highly probable. The observation that severe clinical complications may occur highlights the need to strengthen surveillance for this emerging virus, and, in the event of a ZIKV outbreak, establish rigorous clinical monitoring to detect GBS or other unusual clinical manifestations.
The authors declare no conflicts of interest.
- 4Perinatal transmission of Zika virus, French Polynesia. Euro Surveill 2014; 19: pii: 20751., , et al.
- 5Zika virus infection complicated by Guillain–Barré syndrome—case report, French Polynesia, December 2013. Euro Surveill 2014; 19: pii: 20720., , et al.
- 9Potential for Zika virus transmission through blood transfusion demonstrated during an outbreak in French Polynesia, November 2013 to February 2014. Euro Surveill 2014; 19: pii: 20761., , et al.
- 10Institut de Veille Sanitaire. Bulletin hebdomadaire international du 5 au 11 Mars 2014. N°142. Available at: http://www.invs.sante.fr/Publications-et-outils/Bulletin-hebdomadaire-international/Tous-les-numeros/2014/Bulletin-hebdomadaire-international-du-5-au-11-mars-2014.-N-442 (last accessed 1 June 2014).