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Chromobacterium violaceum is a free-living Gram-negative bacterium found in soil and aquatic habitats; abundantly present in the Brazilian Amazon, it is an important example of exploitable microbial diversity of the tropics. In this study, 24 strains from the Brazilian Amazon and ATCC 12472(T) were investigated for biocontrol potential of seven fungi pathogenic to soybean [Glycine max (L.) Merril] seed. Both cells and the supernatants of two Brazilian strains, 07-1 and 27-1, together with ATCC 12472(T) were strongly antagonistic to six out of the seven fungi. The antifungal activity of the Brazilian strains to Fusarium sp., Phomopsis sp. and Cercospora kikuchi was consistently stronger than that of ATCC 12472(T). In addition, the two Brazilian strains, but not ATCC 12472(T), were effective against Corynespora sp., and all three strains and their supernatants were equally effective against Aspergillus sp. and Colletotrichum sp. None of the strains had antifungal activity against Botroyodiplodia sp. Three potential mechanisms related to the antibiosis were investigated: violacein toxicity, cyanide production and chitinolytic activity; however, it was not possible to associate any of them with the antifungal activity. The results highlight the biotechnological potential still to be explored within the poorly characterized microbial biodiversity of the tropics.

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Introduction:In Brazil, Mato Grosso (MT) has the highest number of hantavirus cardiopulmonary syndrome cases. Our study aimed to identify anti-hantavirus antibodies in the sera of patients from Sinop, MT, presenting with acute febrile illness. Methods: A retrospective analysis of data for 198 sera samples assessed using enzyme-linked immunosorbent assay (ELISA) was conducted. Results: Immunoglobulins G (IgGs) against the hantavirus nucleoprotein were found in 13.6% of the tested sera. No sample had immunoglobulin M (IgM) antibodies to hantavirus. Seropositivity occurred mainly in female residents in urban areas who worked around the household. Conclusions: Our findings suggest circulation of hantavirus in Sinop.Keywords: Zoonosis. Serosurvey study. Hantavirus.Hantaviruses (genus Hantavirus, family Bunyaviridae) are emerging zoonotic viruses of great importance for public health. In South America, the rodents of the Sigmodontinae subfamily are reservoirs of these viruses. Some hantaviruses infect humans, causing either hemorrhagic fever with renal syndrome (HFRS) and/or hantavirus cardiopulmonary syndrome (HCPS) (1) .The first cases of HCPS diagnosed in Brazil occurred in 1993. Since then, more than 1,920 cases of hantavirus have been notified in all Brazilian regions, with a case fatality rate of up to 39.5%. Mato Grosso (MT) is the leading state for HCPS cases and accounts for 16.1% of the total notified cases in Brazil. In a previous study conducted in the municipality of Sinop, Mato Grosso State, we carried out an epidemiological surveillance for arboviruses in 198 sera samples from patients presenting with acute febrile illness and clinical-epidemiological diagnoses of dengue. The results showed 46 samples positive for arboviruses. However, it was intriguing that more than 70% of the patients did not have dengue or other arbovirus infections that were tested for (2) . To address the possibility of hantavirus infection, we investigated the presence of antibodies against the hantavirus nucleoprotein in these febrile patients.Sinop is a municipality located 503km from the capital Cuiabá, in a geographical transition zone between a savannah and rainforest. The city was founded in 1974 and currently has an estimated population of approximately 130,000 inhabitants with 17.1% of them living in rural areas. The economic activities include an intensive agriculture based on the grain production, animal husbandry, logging, and human services. All of the sera analyzed in this study were part of the serum bank of the Laboratory of Immunology and Molecular Biology of Universidade Federal de Mato Grosso (UFMT), Campus of Sinop, which have been previously described in detail (2) . At the time of blood collection, the patients filled out a questionnaire that contained their epidemiological data, sex, age, occupation, address and region of birth, as well as information about any contact with rural or forested areas, and contact with rodents. These data were collected to analyze the risk factors associated with infect...

Introduction: DENV-2 is the cause of most dengue epidemics worldwide and is associated with severe cases. Methods: We investigated arboviruses in 164 serum samples collected from patients presenting with clinical symptoms of dengue fever and 152 mosquito pools. Results: We detected the Asian II genotype of DENV-2 in humans and mosquitoes. Our results confirmed the circulation of the Asian II genotype in Brazil, in addition to the prevalent Asian/American genotype. Conclusions: The detection of Asian II genotype of DENV-2 in mosquito pools collected in a forest park may be related to a spillback event of human dengue virus.

Microbial colonies were replicated on YNB® agar plates overlaid with soft agar containing the glucoseoxidase/peroxidase (BIOTROL®) system. The pink color developed around the colonies was the result of the reaction of the glucose generated by the extracellular hydrolysis of lactose by β-galactosidase, indicating secretion of this enzyme. This method proved to be very convenient for testing hundreds of colonies grown on agar plates for β-galactosidase secretion by microbial cells.

The Amazon rainforest is considered the largest reservoir of culicids and arboviruses in the world. It has been under intense human‐driven alteration, especially in the so‐called ‘Arc of Deforestation’, located in the eastern and southern regions. The emergence and transmission of infectious diseases are increasing, potentially due to land‐use change. We used landscape‐scale mosquito surveillance across a forest fragmentation gradient in the southern Amazon to evaluate the relationship between forest disturbance and the composition and structure of mosquito communities with a particular focus on the potential for arbovirus emergence in the region. Generalized linear models and logistic regression were used to associate the degree of landscape disturbance with arbovirus vectors’ richness and abundance. A total of 1,960 culicids, belonging to 50 species, were collected from 2015 to 2016. Among these species, 20 have been associated with the transmission of arboviruses. Our results show an association of land use, more specifically small size of forest remnants with more irregular shape and higher edge density, with the increase of arbovirus vectors’ richness and abundance. Six species of mosquito vectors exhibited a higher probability of occurrence in landscapes with medium or high degrees of disturbance. Our results indicate that land‐use change influences mosquito communities with potential implications for the emergence of arboviruses.