Unrecognized Emergence of Chikungunya Virus during a Zika Virus Outbreak in Salvador, Brazil.
Unrecognized Emergence of Chikungunya Virus during a Zika Virus Outbreak in Salvador, Brazil.
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DOI：
10.1371/journal.pntd.0005334
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发表时间：
2017-01
影响因子：
3.8
通讯作者：
Ribeiro GS
中科院分区：
文献类型：
--
作者：
Cardoso CW;Kikuti M;Prates AP;Paploski IA;Tauro LB;Silva MM;Santana P;Rego MF;Reis MG;Kitron U;Ribeiro GS
Chikungunya virus (CHIKV) entered Brazil in 2014, causing a large outbreak in Feira de Santana, state of Bahia. Although cases have been recorded in Salvador, the capital of Bahia, located ~100 km of Feira de Santana, CHIKV transmission has not been perceived to occur epidemically, largely contrasting with the Zika virus (ZIKV) outbreak and ensuing complications reaching the city in 2015. This study aimed to determine the intensity of CHIKV transmission in Salvador between November 2014 and April 2016. Results of all the CHIKV laboratory tests performed in the public sector were obtained and the frequency of positivity was analyzed by epidemiological week. Of the 2,736 tests analyzed, 456 (16.7%) were positive. An increasing in the positivity rate was observed, starting in January/2015, and peaking at 68% in August, shortly after the exanthematous illness outbreak attributed to ZIKV. Public health authorities and health professionals did not immediately detect the increase in CHIKV cases, likely because all the attention was directed to the ZIKV outbreak and ensuing complications. It is important that regions in the world that harbor arbovirus vectors and did not experience intense ZIKV and CHIKV transmission be prepared for the potential co-emergence of these two viruses. Since 2014, Brazil has experienced simultaneous transmission of dengue (DENV), chikungunya (CHIKV) and Zika virus (ZIKV), hampering clinical differentiation of infections due to the close manifestations caused by these viruses. Salvador, Brazil’s third largest city, was one of the cities most affected by those arboviral diseases. While a large acute exantematous illness (AEI) outbreak attributed to ZIKV has been recognized in the city, transmission of CHIKV appeared to have been much less intense. To obtain a comprehensible overview of the recent epidemiological situation, we investigated the proportion of chikungunya positive results among Salvador residents that were tested for CHIKV infections from November 2014 to April 2016. We demonstrated a high rate of CHIKV detection in serum samples during June-November 2015, shortly after an AEI outbreak attributed to ZIKV. The increase in CHIKV cases was not promptly detected by public health authorities and health professionals, likely because all the attention was directed to the ZIKV outbreak and its ensuing complications. It is important for regions that harbor Ae. aegypti (and potentially other vectors), but have not yet been subject to much transmission of ZIKV, CHIKV, DENV (and to potential other new and emerging arbovirus), to be prepared for the potential co-circulation of these viruses and associated diagnostic challenges.
