LETTERS Zika Virus, W. Thane Hancock, assay suggested that a dengue virus Maria Marfel, and Martin Bel (DENV) was the causative agent. French Polynesia, Author affiliation: Yap State Department of In June 2007, samples were sent for South Pacific, 2013 Health Services, Colonia, Yap, Federated confirmatory testing to the Arbovirus States of Micronesia Diagnostic Laboratory at the Centers To the Editor: We wish to clarify for Disease Control and Prevention DOI: http://dx.doi.org/10.3201/eid2011.141253 an inaccuracy in a letter in Emerging (CDC, Fort Collins, CO, USA).” Infectious Diseases by Cao-Lormeau I apologize to the Yap Epinet References et al. (1). The authors state “In 2007, Team for this inaccuracy, and I en- the first ZIKV outbreak reported out- 1. Cao-Lormeau VM, Roche C, Teissier A, courage the reader to consult the arti- side Africa and Asia was retrospec- Robin E, Berry AL, Mallet HP, et al. Zika cles by Lanciotti et al. (3) and Duffy tively documented from biological virus, French Polynesia, South Pacific, et al. (4) to get a complete descrip- 2013. Emerg Infect Dis. 2014;20:1085–6. samples from patients on Yap Island, http://dx.doi.org/10.3201/eid2006.140138 tion of the clinical and laboratory Federated States of Micronesia, North 2 Duffy MR, Chen TH, Hancock WT, investigations conducted during the Pacific, who had received an incorrect Powers AM, Kool JL, Lanciotti RS. ZIKV outbreak in Yap State. If data diagnosis of dengue virus (DENV).” Zika outbreak on Yap Island, Feder- and laboratory protocols (reverse ated States of Micronesia. N Engl J Although the first outbreak of Zika vi- Med. 2009;360:2536–43. http://dx.doi. transcription PCR) related to this rus (ZIKV) infection reported outside org/10.1056/NEJMoa0805715 first ZIKV outbreak in the Pacific had Africa or Asia was in Yap, it was not not been available to the scientific retrospectively identified from serum Address for correspondence: W. Thane community, identification of ZIKV samples incorrectly diagnosed as posi- Hancock, Yap State Department of Health as the cause of an outbreak in French tive for dengue virus. The outbreak Services, EpiNet, PO Box 148, Colonia, Yap Polynesia in 2013 would have been was first identified by the Yap State 96943, Federated States of Micronesia; email: greatly delayed. Department of Health Services, and [email protected] an investigation to determine the etio- Van-Mai Cao-Lormeau logic agent was initiated. In Response: I want to respond to Institut Louis Malardé, Papeete, Tahiti, Although dengue was initially part the letter by Hancock et al. (1) regard- French Polynesia of the differential diagnosis, and a few ing the previously published letter, DOI: http://dx.doi.org/10.3201/eid2011.141380 patients had evidence of IgM against Zika Virus, French Polynesia, South dengue virus by a rapid diagnostic test, Pacific, 2013 (2). My comment aims References clinicians in Yap believed that the clini- to clarify an inaccuracy in the follow- cal syndrome was not consistent with ing sentence. “In 2007, the first Zika 1. Hancock WT, Marfel M, Bel M. Zika dengue. Thus, assistance was request- outbreak ever reported outside Africa virus, French Polynesia, South Pacific, 2013. Emerg Infect Dis. 2014;20:1961. ed from the US Centers for Disease and Asia was retrospectively docu- 2. Cao-Lormeau VM, Roche C, Teissier A, Control and Prevention and the World mented from biological samples of pa- Robin E, Berry AL, Mallet HP, et al. Zika Health Organization to strengthen the tients on Yap Island, Federated States virus, French Polynesia, South Pacific, epidemiologic investigation and pro- of Micronesia, North Pacific, who had 2013. Emerg Infect Dis. 2014;20:1085–6. http://dx.doi.org/10.3201/eid2006.140138 vide confirmatory laboratory testing. received an incorrect diagnosis of den- 3. Lanciotti RS, Kosoy OL, Laven JJ, Serum samples collected during gue virus (DENV)” (2). Velez JO, Lambert AJ, Johnson AJ, the active investigation were sent to the I recognize that this sentence does et al. Genetic and serologic properties of Arboviral Diseases Diagnostic Labora- not provide an accurate description of Zika virus associated with an epidemic, Yap State, Micronesia, 2007. Emerg In- tory at the Centers for Disease Control the efforts in Yap State to investigate fect Dis. 2008;14:1232–9. http://dx.doi. and Prevention where testing deter- the outbreak and further confirm that org/10.3201/eid1408.080287 mined that the cause of the infections it was caused by Zika virus (ZIKV). 4. Duffy MR, Chen TH, Hancock WT, was ZIKV (2). This discovery of ZIKV As specified in the article by Lanciot- Powers AM, Kool JL, Lanciotti RS, et al. Zika outbreak on Yap Island, Fed- as the etiologic agent was not achieved ti et al. (3), outbreak investigations erated States of Micronesia. N Engl through retrospective testing of serum continued although initial laboratory J Med. 2009;360:2536–43. http://dx.doi. from patients incorrectly diagnosed as testing suggested dengue virus as the org/10.1056/NEJMoa0805715 having dengue, but rather the result of causative agent: “In April 2007, an an active, coordinated investigation by epidemic of rash, conjunctivitis, and Address for correspondence: Van-Mai Cao- the Yap State Department of Health arthralgia was noted by physicians in Lormeau, Institut Louis Malardé, PO Box 30, Services with instrumental assistance Yap State, Federated States of Micro- 98713 Papeete, Tahiti, French Polynesia; email: from international partners. nesia. Laboratory testing with a rapid [email protected] 1960 Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 20, No. 11, November 2014.