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Emerging arboviruses in the Pacific [Dengue, Zika, chikungunya]

Saturday, 23rd of January 2016 Print

Emerging arboviruses in the Pacific [Dengue, Zika, chikungunya]

Van-Mai Cao-Lormeau,

Didier Musso

 

Best viewed at http://dx.doi.org/10.1016/S0140-6736(14)61977-2

 

The Lancet,Volume 384, No. 9954, p1571–1572, 1 November 2014

Correspondence

Dengue virus is the causal agent of dengue fever and is typically characterised by fever, myalgia, arthralgia, rash, and sometimes severe and life-threatening clinical symptoms. This virus is regarded as the greatest threat to global public health of arthopod-borne viruses (arboviruses). However, during the past decade additional mosquito-borne viruses, including chikungunya virus, which causes fever and acute polyarthralgia, have successfully expanded to geographical areas where only dengue epidemics used to be reported, particularly to the tropical oceanic regions. In 2005, chikungunya virus was recorded in the Indian Ocean islands, and from the end of 2013, reached the Caribbean.1 In 2014, concomitant outbreaks have happened in the Pacific due to dengue virus, chikungunya virus, and Zika virus—another mosquito-borne virus that mostly causes mild fever, joint pain, conjunctivitis, and rash.2, 3, 4

Substantial changes in epidemiology of mosquito-borne diseases in tropical oceanic regions are probably caused by many and difficult to address factors. However, a review of the epidemiological situation in the Pacific from the past several years shows that the present crisis could be the product of a gradual process. In the Pacific the situation worsened during a 7-year period; the predominant circulation of a single dengue virus serotype (dengue virus serotype [DENV]-1) changed to co-circulation of several virus serotypes (DENV-4 in 2007, then also with DENV-2, which caused some sporadic outbreaks, and co-circulation of DENV-3 in 2013),2 and concurrent emergence of mosquito-borne viruses not previously reported in the region (figure).

Figure

Expansion of dengue, chikungunya, and Zika viruses in Pacific Island countries and territories between 2007 and 2014

Isl=island. Plot marks represent the occurrence of an outbreak. Imported cases from the Pacific with mosquito-borne viral infection confirmed back to their home country were not reported if additional information on the possible occurrence of an outbreak in the Island Country visited was not available. Data (up to September, 2014) are from ProMED (http://www.promedmail.org), WHO western Pacific Region (http://www.wpro.who.int/southpacific/), Pacific Public Health Surveillance Network (http://www.spc.int/phs/PPHSN; http://www.spc.int/phd/epidemics/), Ministry of Health of New Zealand (www.health.govt.nz), Direction des Affaires Sanitaires et Sociales New Caledonia (http://www.dass.gouv.nc/portal/page/portal/dass/), Direction of Health French Polynesia (http://www.hygiene-publique.gov.pf/spip.php?article120), or from reports by the Pacific Islands health authorities on the results of molecular tests done at Institut Louis Malardé, French Polynesia, as part of the outbreaks investigations supported by WHO.

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In 2007, the Yap State, the Federated States of Micronesia reported the first outbreak of Zika virus outside of Africa and Asia.5 Subsequent infections of Zika virus in other Pacific islands were not reported until 2013, when this virus reappeared in French Polynesia and then disseminated throughout the Pacific.4 The first autochthonous chikungunya infections in the region were reported in 2011 in New Caledonia. Chikungunya outbreaks occurred in Papua New Guinea in 2012, the Yap State in 2013, and Tonga, American Samoa, Samoa, and Tokelau in 2014.

Tropical oceanic regions host potential vectors for many arboviruses that local populations are mostly naive for, making these regions an ideal setting for such emerging viruses to spread; thus greatly contributing to the globalisation of dengue, chikungunya, and Zika viruses as threats to public health.

We declare no competing interests.

We thank Anita Teissier and Claudine Roche for doing molecular tests on specimens received from Pacific Island Countries. We thank Eric Nilles, Division of Pacific Technical support, WHO, and laboratory staff and public health authorities from Pacific island countries for doing laboratory investigations and sharing information. We thank WHO for support for molecular testing.

References

  1. Leparc-Goffart, I, Nougairede, A, Cassadou, S, Prat, C, and de Lamballerie, X. Chikungunya in the Americas. Lancet. 2014; 383: 514
  2. Cao-Lormeau, VM, Roche, C, Musso, D et al. Dengue virus type 3, South Pacific Islands, 2013. Emerg Infect Dis. 2014; 20: 1034–1036
  3. Roth, A, Hoy, D, Horwood, PF et al. Preparedness for threat of Chikungunya in the Pacific. Emerg Infect Dis. 2014; 20: e130696
  4. Musso, D, Nilles, EJ, and Cao-Lormeau, VM. Rapid spread of emerging Zika virus in the Pacific area. Clin Microbiol Infect. 2014; DOI: http://dx.doi.org/10.1111/1469-0691.12707 (published online June 7.)
  5. Duffy, MR, Chen, TH, Hancock, WT et al. Zika outbreak on Yap Island, Federated States of Micronesia. N Engl J Med. 2009; 360: 2536–2543

 

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