Retrospective molecular investigation of Mayaro and Oropouche viruses at the human-animal interface in West-central Brazil, 2016-2018

Mayaro virus (MAYV, Togaviridae) and Oropouche orthobunyavirus (OROV, Peribunyaviridae) are emerging enzootic arboviruses in Latin America. Outbreaks of febrile illness associated with MAYV and OROV have been reported among humans mainly in the northern region of Brazil since the 1980s, and recent data suggest these viruses have circulated also in more populated areas of western Brazil. MAYV shares mosquito vectors with yellow fever virus and it has been historically detected during yellow fever epidemics. Aiming to investigate the transmission of OROV and MAYV at the human-animal interface during a yellow fever, chikungunya and Zika outbreaks in Brazil, we conducted a retrospective molecular investigation in 810 wild and domestic animals, 106 febrile patients, and 22.931 vectors collected from 2016 to 2018 in Cuiaba and Campo Grande metropolitan regions, western Brazil. All samples tested negative for OROV and MAYV RNA by RT-qPCR. Findings presented here suggest no active circulation of MAYV and OROV in the sampled hosts. Active surveillance and retrospective investigations are instrumental approaches for the detection of cryptic and subclinical activity of enzootic arboviruses and together serve as a warning system to implement appropriate actions to prevent outbreaks.

Cubane and cubanoid: Structural, optoelectronic and thermodynamic properties from DFT and TD-DFT method

In this paper, we report structural, electronic and optical properties of cubane (C₈H₈) and cubanoids (cubane-like molecules) using Density Functional Theory (DFT). The cubanoids are cubanes for which Carbon atoms have been substituted by Nitrogen (N), Phosphorus (P), Boron (B), Silicon (Si), Arsenic (As), Antimony (Sb) or Bismuth (Bi) atoms. These molecules presented exceptional stability with several different symmetry point groups, being the majority T_d. All calculated vibrational frequencies are positive for any studied molecules indicating that all these structures are in a stable state. The HOMO-LUMO gaps and DOS were calculated converged towards to values between 1.87 eV and 5.61 eV, actually showing promising electronic properties (Just for comparison, the cubane energy gap is 7.50 eV). The optical absorptions were also calculated for the cubanoid structure using the Time-Dependent Density Functional Theory (TD-DFT). Their dependence on the wavelength is analyzed, where five of theses structures absorb on the visible region. Finally, the extrapolation of thermodynamic properties indicates that these cubanoid could be potentially synthesized spontaneously, where four structures, the synthesis would occur for temperatures below 400 K, while for Si₄Bi₄H₄ structure, the synthesis would occur at room temperature.

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.

The inability of a dengue NS1 ELISA to detect Zika infections

The presence of dengue virus (DENV), Zika virus (ZIKV) and Chikungunya virus (CHIKV) in Brazil, may result in a difficult diagnosis due to the signs and symptoms shared by those. Moreover, as DENV and ZIKV belong to the same family, serological assays may show a high rate of cross-reactivity. Here, we evaluated a Dengue NS1 capture assay for early and differential diagnosis of dengue during the Zika epidemic occurred in Brazil in 2016. Samples (n = 227) from 218 patients included sera, plasma and urine from previously confirmed acute cases of Zika, dengue and Zika/dengue co-infections. Nine of those patients presented two specimens. The Dengue NS1 test was very specific for dengue diagnosis (99.32%), even in the co-circulation with ZIKV, and exhibited a high accuracy in not detecting acute Zika infections (92.43%). Our findings showed that the dengue NS1 capture test analyzed here was not able to recognize the ZIKV NS1 and its potential for cross-reaction.

Human T cell responses to Dengue and Zika virus infection compared to Dengue/Zika coinfection

INTRODUCTION

Zika virus (ZIKV) and dengue virus (DENV) co-circulated during latest outbreaks in Brazil, hence, it is important to evaluate the host cross-reactive immune responses to these viruses. So far, little is known about human T cell responses to ZIKV and no reports detail adaptive immune responses during DENV/ZIKV coinfection.

METHODS

Here, we studied T cells responses in well-characterized groups of DENV, ZIKV, or DENV/ZIKV infected patients and DENV-exposed healthy donors. We evaluated chemokine receptors expression and single/multifunctional frequencies of IFNγ, TNF, and IL2-producing T cells during these infections. Even without antigenic stimulation, it was possible to detect chemokine receptors and IFNγ, TNF, and IL2-producing T cells from all individuals by flow cytometry. Additionally, PBMCs' IFNγ response to DENV NS1 protein and to polyclonal stimuli was evaluated by ELISPOT.

RESULTS

DENV and ZIKV infections and DENV/ZIKV coinfections similarly induced expression of CCR5, CX3CR1, and CXCR3 on CD4 and CD8 T cells. DENV/ZIKV coinfection decreased the ability of CD4+ T cells to produce IFNγ+ , TNF+ , TNF +  IFNγ+ , and TNF +  IL2+ , compared to DENV and ZIKV infections. A higher magnitude of IFNγ response to DENV NS1 was found in donors with a history of dengue infection, however, a hyporesponsiveness was found in acute DENV, ZIKV, or DENV/ZIKV infected patients, even previously infected with DENV.

CONCLUSION

Therefore, we emphasize the potential impact of coinfection on the immune response from human hosts, mainly in areas where DENV and ZIKV cocirculate.

Clinical and Laboratory Profile of Zika and Dengue Infected Patients: Lessons Learned From the Co-circulation of Dengue, Zika and Chikungunya in Brazil

Background: The current triple epidemic caused by dengue, zika and chikungunya constitutes a serious health problem in Brazil. The aim of this study was to investigate acute samples (up to the 7 days of symptoms) from patients presenting acute fever syndrome suspected as arboviral infection and characterize the clinical and laboratorial profile during the co-circulation of dengue, zika and chikungunya in Campo Grande, Mato Grosso do Sul (MS), midwest region of Brazil. Methods: All suspected cases (n=134) were tested by using serological and molecular diagnostic tests including DENV, ZIKV and CHIKV RT-PCR, Dengue nonstructural protein 1 (NS1) antigen capture ELISA, anti- DENV IgM ELISA and anti-CHIKV IgM ELISA. In addition, clinical, hematological and biochemical parameters of infected patients were analyzed. Results: It was observed that 79.1% of the blood samples were confirmed for ZIKV and/or DENV infection Of those, 38.0% patients were DENV monoinfected, 26.8% were ZIKV monoinfected and 13.4% were DENV/ZIKV co-infected. Seven patients presented Chikungunya IgM antibodies indicating a previous CHIKV infection. Common symptoms included fever, rash, arthralgia, myalgia, prostration, headache and conjunctivitis. Statistical analysis showed that pruritus and edema were associated with ZIKV infection while prostration and vomiting were more associated with dengue. Additionally, total protein and ALT levels were significantly different in DENV patients compared to ZIKV ones. Some DENV infected patients as well as co-infected needed hospitalization and venous hydration. Otherwise, most ZIKV infected patients presented mild clinical course. Among the pregnant women studied (n=11), three were ZIKV monoinfected while four were DENV monoinfected and two were DENV-1/ZIKV coinfected. In general, normal birth outcomes were observed except for the death due to respiratory insufficiency of one baby born to a mother coinfected with DENV-1/ZIKV. Conclusions: Herein, we provide evidence of the co-circulation of DENV, ZIKV and CHIKV infections in the Campo Grande, MS, Brazil, with a high frequency of DENV-1/ZIKV coinfection. Laboratorial diagnosis poses a challenge where those arboviruses are endemic and differential diagnosis proved to imperative for cases characterization. The knowledge about disease severity during arbovirus coinfections is still scarce and there are several issues emphasizing the importance of adequate management of patients at risk areas.

Diversity of Calliphoridae (Diptera) in Brazil's Tinguá Biological Reserve

The Calliphoridae are flies of great ecological, medical and sanitary importance because they are decomposers of organic matter, mechanical vectors of pathogenic agents, and causers of myiasis. This paper attempts to ascertain the diversity of Calliphoridae in the Tinguá Biological Reserve and correlate meteorological data (temperature, relative humidity of the air, and precipitation) with the occurrence of these flies. The study was conducted at a site in the Tinguá Biological Reserve, located in the municipality of Nova Iguaçu, state of Rio de Janeiro, Brazil. Four traps were set up using chicken viscera as bait. The experiment was conducted over the period of May 2001 to April 2002, with two monthly collections. The captured flies were killed with ether and conserved in 70% alcohol and identified in the Laboratory of Diptera Studies (UNIRIO) and the Laboratory of Vector Insect Biology and Control (FIOCRUZ), both headquartered in the city of Rio de Janeiro, RJ, Brazil. A total of 1,987 insects were captured, 37.5% belonging to the family Calliphoridae, 29.4% to Muscidae, 16.0% to Sarcophagidae, and 17.1% to other families. The most representative species found was Phaenicia eximia (47.0%), followed by Hemilucilia semidiaphana (23.6%), Mesembrinella bellardiana (13.7%), Hemilucilia segmentaria (7.5%), Chloroprocta idioidea (4.9%), Chrysomya albiceps (1.2%), Chrysomya megacephala (0.9%), Phaenicia sericata (0.6%), Eumesembrinella sp. (0.5%), and Chrysomya putoria (0.1%). Large numbers of Calliphoridae were noted in May, June, September and January, coinciding with low rainfall and an average temperature of 21.8 to 27.0 degrees C. A negative correlation was found between the number of Calliphoridae captured and meteorological factors.

[Migratory flow of cases of malaria in Cuiabá/MT, 1986]

Foram estudadas 2.406 pessoas que procuraram a SUCAM/Cuiabá para diagnóstico e tratamento da malária. Destes, 1.151 tiveram lâminas positivas através da gota espessa: 720 P. vivax, 421 P. falciparum e 10 forma mista; 1.255 foram negativos à pesquisa de hematozoários. As entrevistas foram realizadas através de questionário padronizado onde procurou-se categorizar as pessoas conforme o sexo, idade, profissão, naturalidade, renda mensal, procedência e destino. Da análise efetuada vimos que os casos de malária originaram-se mais da micro-região Norte-Matogrossense para a Baixada Cuiabana (56,5%), colocando em risco toda a população desta micro-região, que encontra-se com borrificaçâo suspensa (DDT) na maioria das localidades. É também importante o fluxo de casos de malária do Estado de Rondônia (20,6%) e para os Estados da região Sul e Sudeste (4,4%) do país. Concluímos que medidas urgentes devam ser tomadas para a reformulação da campanha de controle da malária, planejando a intervenção nos aspectos sociais, políticos e econômicos.