Was It Chikungunya? Laboratorial and Clinical Investigations of Cases Occurred during a Triple Arboviruses' Outbreak in Rio de Janeiro, Brazil.

Thiara Manuele Alves De Souza,Victor Edgar Fiestas Solórzano,Larissa Cristina Teixeira Tomé,Paulo Vieira Damasco,Luiz José De Souza,Gabriel Macedo Costa Guimarães,Flavia Barreto Dos Santos,Juan Camilo Sanchez-Arcila,Sandro Patroca Da Silva,Fernanda De Bruycker-Nogueira,Luzia Maria De Oliveira-Pinto,Monique Da Rocha Queiroz Lima,Raquel Curtinhas De Lima,Elzinandes Leal De Azeredo,Iury Amâncio Paiva,Mariana Rosa Inácio Coelho

doi:10.3390/pathogens11020245

Abstract

The co-circulation of chikungunya virus (CHIKV), dengue virus (DENV) and Zika virus (ZIKV) in Rio de Janeiro (RJ), Brazil, caused a challenging triple epidemic, as they share similar clinical signs and symptoms and geographical distribution. Here, we aimed to investigate the clinical and laboratorial aspects of chikungunya suspected cases assisted in RJ during the 2018 outbreak, focusing on the differential diagnosis with dengue and zika. All suspected cases were submitted to molecular and/or serological differential diagnostic approaches to arboviruses. A total of 242 cases suspected of arbovirus infection were investigated and 73.6% (178/242) were molecular and/or serologically confirmed as chikungunya. In RT-qPCR confirmed cases, cycle threshold (Ct) values ranged from 15.46 to 35.13, with acute cases presenting lower values. Chikungunya cases were mainly in females (64%) and the most frequently affected age group was adults between 46 to 59 years old (27%). Polyarthralgia affected 89% of patients, especially in hands and feet. No dengue virus (DENV) and Zika virus (ZIKV) infections were confirmed by molecular diagnosis, but 9.5% (23/242) had serological evidence of DENV exposure by the detection of specific anti-DENV IgM or NS1, and 42.7% (76/178) of chikungunya positive cases also presented recent DENV exposure reflected by a positive anti-DENV IgM or NS1 result. A significantly higher frequency of arthritis (p = 0.023) and limb edema (p < 0.001) was found on patients with CHIKV monoinfection compared to dengue patients and patients exposed to both viruses. Lastly, phylogenetic analysis showed that the chikungunya cases were caused by the ECSA genotype. Despite the triple arboviruses’ epidemic in the state of RJ, most patients with fever and arthralgia investigated here were diagnosed as chikungunya cases, and the incidence of CHIKV/DENV co-detection was higher than that reported in other studies.

Highlights

Chikungunya virus (CHIKV) belongs to the Togaviridae family and to the Alphavirus genus [1,2], having a spherical and enveloped viral particle that measures approximately 60–70 nm in diameter
262 cases of febrile illness compatible with arboviral infection were selected for differential laboratorial diagnosis, at Rio-Laranjeiras Hospital (RJ, n = 33) and at Plantadores de Cana Hospital (Campos dos Goytacazes, n = 229)
All 242 cases were tested for anti-chikungunya virus (CHIKV) IgM and 63.2% (153/242) were positive, whilst anti-CHIKV IgG was investigated in 164 and was detected in 35.4% (58/164) of the cases

Summary

Introduction

Chikungunya virus (CHIKV) belongs to the Togaviridae family and to the Alphavirus genus [1,2], having a spherical and enveloped viral particle that measures approximately 60–70 nm in diameter. The genome consists of a single-stranded positive polarity RNA that measures approximately 11.8 kb in length, encoding four non-structural proteins: NSP1–4, and five structural proteins: C-E3-E2-6K-E1 [1,3,4]. Three different CHIKV genotypes have been described: West African, East-Central-South African (ECSA) and Asian [5,6]. The gastrointestinal tract can be affected, causing nausea, vomiting and diarrhea [7]. The symptoms may last for three months, when the disease is considered to have reached the subacute form, or even years, causing severe, debilitating and persistent arthralgia [8,9]

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