Oropouche Virus Exposure in Febrile Patients during Chikungunya Virus Introduction in the State of Amapá, Amazon Region, Brazil.

Oropouche orthobunyavirus (OROV) is an arbovirus transmitted by midges that has been involved in outbreaks throughout Central and South America. In Brazil, human cases have been historically concentrated in the northern region of the country. Oropouche fever in humans range from mild clinical signs to rare neurological events, and is considered a neglected tropical disease in Brazil. Due to the clinical similarities to other arboviruses, such as chikungunya and dengue viruses, OROV infections are likely to be underreported. Chikungunya virus (CHIKV) cases in Brazil were first recognized in 2014 in the states of Amapá and Bahia in the north and northeast regions, respectively. Both OROV and CHIKV cause nonspecific symptoms, making clinical diagnosis difficult in a scenario of arbovirus cocirculation. Aiming to investigate OROV transmission during the CHIKV introduction in the state of Amapá located in the Brazilian Amazon, we conducted a retrospective molecular (RT-qPCR) and serological investigation in febrile cases (N = 166) collected between August 2014 and May 2015. All acute serum samples were negative for OROV RNA using RT-qPCR. However, neutralizing antibodies for OROV were detected using a plaque reduction neutralization test (PRNT90) in 10.24% (17/166) of the patients, with neutralizing antibody titers ranging from 20 to ≥640, suggesting the previous exposure of patients to OROV. Regarding CHIKV, recent exposure was confirmed by the detection of CHIKV RNA in 20.25% (33/163) of the patients and by the detection of anti-CHIKV IgM in 28.57% (44/154) of the patients. The additional detection of anti-CHIKV IgG in 12.58% (19/151) of the febrile patients suggests that some individuals had been previously exposed to CHIKV. Whether the OROV exposure reported here occurred prior or during the CHIKV circulation in Amapá, is unknown, but because those arboviral infections share similar clinical signs and symptoms, a silent circulation of enzootic arboviruses during the introduction of exotic arboviruses may occur, and highlights the importance of syndromic cases' surveillance to arboviruses in Brazil.

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

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.

Clinical, Virological, and Immunological Profiles of DENV, ZIKV, and/or CHIKV-Infected Brazilian Patients.

BACKGROUND: Arboviruses co-circulating within a population that are transmitted by the same vector have the potential to cause coinfections. Coinfections with dengue virus (DENV), Zika virus (ZIKV), and chikungunya virus (CHIKV) have been occurring in Brazil, but it is not well-understood how human responses vary during mono- or coinfections and whether they play different roles in pathogenesis. METHODS: We investigated the clinical, virological, and immunological status during patients' acute infections, focusing on the CCL/CXC chemokines, proinflammatory, as well as anti-inflammatory cytokines levels quantified by ELISAs. Viral load was determined by qRT-PCR in serum samples from 116 acute DENV, ZIKV, CHIKV, DENV/ZIKV, and CHIKV/ZIKV-infected adult patients from Brazil. RESULTS: Most of the acute patients displayed fever, headache, prostration, and myalgia, regardless of the type of arbovirus infection. Zika viral load was higher in CHIKV/ZIKV coinfected patients compared with ZIKV or DENV/ZIKV infections. All infected individuals presented increased concentrations of C-X-C motif chemokine ligand 10/interferon protein-10 (CXCL10/IP-10), C-C motif chemokine ligand 2/monocyte chemoattractant protein-1 (CCL2/MCP-1), and tumor necrosis factor alpha (TNF-α) compared to healthy donors. Interestingly, the ZIKV group separated from CHIKV/ZIKV due to higher levels of interleukin-10 (IL-10) and lower levels of TNF-α. While DENV/ZIKV differentiated from CHIKV due to their higher levels of CCL2/MCP-1, in CHIKV- and CHIKV/ZIKV-infected patients, levels of CXC10/IP-10, CCL2/MCP-1, and migration inhibitory factor (MIF) were associated with CHIKV viral load. By contrast, in DENV/ZIKV- and CHIKV/ZIKV-infected patients, levels of CXCL10/IP-10, CCL2/MCP-1, and TNF-α showed a significant inverse correlation with ZIKV viral load. CONCLUSIONS: From all the circulating mediators measured, we detected differences of IL-10, TNF-α, and CCL2/MCP-1 between arbovirus groups. We hypothesize that CXC10/IP-10, CCL2/MCP-1, and MIF in the CHIKV-infected group could regulate the CHIKV viral load, while CXC10/IP-10, CCL2/MCP-1, and TNF-α in DENV/ZIKV, and CHIKV/ZIKV groups, could regulate ZIKV viral load.

Following in the Footsteps of the Chikungunya Virus in Brazil: The First Autochthonous Cases in Amapá in 2014 and Its Emergence in Rio de Janeiro during 2016.

Currently, Brazil lives a triple arboviruses epidemic (DENV, ZIKV and CHIKV) making the differential diagnosis difficult for health professionals. Here, we aimed to investigate chikungunya cases and the possible occurrence of co-infections during the epidemic in Amapá (AP) that started in 2014 when the first autochthonous cases were reported and in Rio de Janeiro (RJ) in 2016. We further performed molecular characterization and genotyping of representative strains. In AP, 51.4% of the suspected cases were confirmed for CHIKV, 71.0% (76/107). Of those, 24 co-infections by CHIKV/DENV, two by CHIKV/DENV-1, and two by CHIKV/DENV-4 were observed. In RJ, 76.9% of the suspected cases were confirmed for CHIKV and co-infections by CHIKV/DENV (n = 8) and by CHIKV/ZIKV (n = 17) were observed. Overall, fever, arthralgia, myalgia, prostration, edema, exanthema, conjunctival hyperemia, lower back pain, dizziness, nausea, retroorbital pain, and anorexia were the predominating chikungunya clinical symptoms described. All strains analyzed from AP belonged to the Asian genotype and no amino acid changes were observed. In RJ, the East-Central-South-African genotype (ECSA) circulation was demonstrated and no E1-A226V mutation was observed. Despite this, an E1-V156A substitution was characterized in two samples and for the first time, the E1-K211T mutation was reported in all samples analyzed.