Epidemiologic and clinical investigations during a chikungunya outbreak in Rio Grande do Norte State, Brazil.

Joelma D Monteiro,Alessandre De Medeiros Tavares,Hannaly W Bezerra Pereira,Joanna Gardel Valverde,Diego G Teixeira,Selma M B Jeronimo,Ingryd Camara Morais,Anne Aline Pereira De Paiva,Cassio Ricardo De Medeiros Souza,João Ciro Fagundes Neto,Brenda Elen Bizerra Alves,Marília Farias De Melo,Josélio M G Araújo,José Veríssimo Fernandes,Yasmin Mesquita Nascimento,Leandro Gurgel De Medeiros,Márcia Cristina Bernardo De Melo Moura,Shawky M Aboelhadid

doi:10.1371/journal.pone.0241799

Joelma D Monteiro, Alessandre De Medeiros Tavares + Show 16 more

Open Access

https://doi.org/10.1371/journal.pone.0241799

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Abstract

The first autochthonous case of chikungunya virus (CHIKV) infection in Brazil was in September 2014 in the State of Amapá, and from there it rapidly spread across the country. The present study was conducted in 2016 in the state of Rio Grande do Norte, and the aims were to describe the epidemiological and the clinical aspects of the CHIKV outbreak. Biological samples from 284 chikungunya suspected cases were screened for CHIKV and Flavivirus (FV) RNA using qRT-PCR. Negative PCR samples were also screened for anti-CHIKV and anti-FVIgM by ELISA. CHIKV RNA were detected in 125 samples mostly occurring from January through March (46%), mainly affecting adults and older adults. We found a gradual decrease in viral RNA over the disease time. Anti-CHIKV IgM was found in 47.5% after negative CHIKV qRT-PCR. Interestingly, 45.0% simultaneously had positive results for CHIKV and FV IgM, suggesting the occurrence of virus co-circulation. The most frequent symptom was fever (91%). Women presented more chance to develop nausea and abdominal pain compared to men. Our data described and allows us to better understand the clinical and epidemiological aspects of the 2016 chikungunya outbreak in Rio Grande do Norte and can help in the early clinical diagnosis of the virus.

Highlights

Chikungunya virus (CHIKV) was first isolated in 1952 in Tanzania, Africa [1, 2]
The Oiapoque cases were caused by the Caribbean genotype of the virus, while the Feira de Santana cases corresponded to the East-Central/South African Genotype (ECSA) [5]
Brazil reported 263,598 cases of chikungunya fever (CF), 145,059 (55.0%) of which were confirmed cases diagnosed between January 3rd to December 10th of 2016, with an incidence rate of 128.9 cases/100,000 inhabitants

Summary

Introduction

The first autochthonous cases of CHIKV in Brazil were confirmed in Oiapoque, Amapa State, in September 2014. A week later, autochthonous cases were confirmed in Feira de Santana, in Bahia state [4]. The Oiapoque cases were caused by the Caribbean genotype of the virus, while the Feira de Santana cases corresponded to the East-Central/South African Genotype (ECSA) [5]. The ECSA genotype was frequently found in CHIKV autochthonous cases diagnosed in the northeast and west-central regions of Brazil [6]. Brazil reported 263,598 cases of chikungunya fever (CF), 145,059 (55.0%) of which were confirmed cases diagnosed between January 3rd to December 10th of 2016, with an incidence rate of 128.9 cases/100,000 inhabitants. The northeast region of the country reported the highest incidence rate of 405.2 cases/100,000 inhabitants, and the state of Rio Grande do Norte reported an incidence of 718.5 cases/100,000 inhabitants [7]

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