Invasion of Tropical Montane Cities by Aedes aegypti and Aedes albopictus (Diptera: Culicidae) Depends on Continuous Warm Winters and Suitable Urban Biotopes

We provide the first evidence of a recent invasion of Aedes aegypti (Linnaeus in Hasselquist, 1762) and Aedes albopictus (Skuse 1894), followed by dengue virus, in tropical montane cities in south-eastern Brazil, Mariana, and Ouro Preto, at mid and high altitudes, respectively. Long-term temperature variation, dengue public data, and sampling of immature and adult mosquitoes (ovitraps and mosquitraps) in contrasting habitats were used to explain the distribution of Aedes in what in these two cities. From 1961 to 2014, the annual temperature increased significantly due to increases in winter temperatures. In the 1990s/2000s, the winter temperature was 1.3°C warmer than in the 1960s, when it varied from 21.2 to 18.9°C. After 2007, the winter temperatures increased and ranged from 21.6 to 21.3°C. The first autochthonous dengue cases in Mariana and Ouro Preto were in 2007, followed by few occurrences until in 2012, when the mean numbers increased three-fold, and peak at 2013. The continuous 'warmer winter' may have trigged the Aedes invasion. Aedes species benefited from higher winter temperatures, which was an important driver of their invasion of the state of Minas Gerais in the 1980s and, more recently, in the remaining montane urban habitats in this region. In both 2009 and 2011, we found more Aedes in Mariana than Ouro Preto, and more Ae. albopictus in green areas and Ae. aegypti in houses, the expected pattern for well-established populations.

In vitro schistosomicidal and antiviral activities of Arctium lappa L. (Asteraceae) against Schistosoma mansoni and Herpes simplex virus-1

Schistosomiasis and herpes diseases represent serious issues to the healthcare systems, infecting a large number of people worldwide, mainly in developing countries. Arctium lappa L. (Asteraceae), known as "bardana" and "burdock", is a medicinal plant popularly used for several purposes, including as antiseptic. In this study, we evaluated the in vitro schistosomicidal and antiherpes activities of the crude extract of A. lappa, which have not yet been described. Fruits of A. lappa L. were extracted by maceration with ethanol: H₂O (96:4 v/v) in order to obtain the hydroalcoholic extract of A. lappa (AL). In vitro schistosomicidal assays were assessed against adult worms of Schistosoma mansoni, while the in vitro antiviral activity of AL was evaluated on replication of Herpes simplex virus type-1 (HSV-1). Cell viability was measured by MTT assay, using Vero cells and chemical composition of AL was determined by qualitative UPLC-ESI-QTOF-MS analysis. UPLC-ESI-QTOF-MS analysis of AL revealed the presence of dibenzylbutyrolactone lignans, such as arctiin and arctigenin. Results showed that AL was not cytotoxic to Vero cells even when tested at 400μg/mL. qPCR results indicated a significant viral load decreased for all tested concentrations of AL (400, 50, and 3.125μg/mL), which showed similar antiviral effect to acyclovir (50μg/mL) when tested at 400μg/mL. Also, AL (400, 200, and 100μg/mL) caused 100% mortality and significantly reduction on motor activity of all adult worms of S. mansoni. Confocal laser scanning microscopy showed tegumental morphological alterations and changes on the numbers of tubercles of S. mansoni worms in a dose-dependent manner after treatment with AL. This report provides the first evidence for the in vitro schistosomicidal and antiherpes activities of AL, opening the route to further schistosomicidal and antiviral studies with AL and their compounds, especially lignans.

Dengue Patients with Early Hemorrhagic Manifestations Lose Coordinate Expression of the Anti-Inflammatory Cytokine IL-10 with the Inflammatory Cytokines IL-6 and IL-8

Dengue is responsible for a wide range of clinical manifestations, ranging from asymptomatic infections to severe cases. The alteration of cytokine levels correlated with clinical characteristics can help determine prognostic markers of the disease and the identification of targets for immunotherapy. We measured the viral load, serotype, and cytokine levels of 212 serum samples from patients with acute dengue infection during days 1-4 after the onset of symptoms. The patients were classified as either with hemorrhagic manifestations (HM) or with no hemorrhagic manifestations (NHM). The cytokines interleukin-6 (IL-6), IL-8, and IL-10 were increased (P < 0.05) in the dengue virus+ group, compared with the control group. A higher viral load (P < 0.05) and IL-6 was detected in the HM group compared with the NHM group. Interestingly, the NHM group demonstrated a significant positive correlation between inflammatory (IL-6 and 8) and anti-inflammatory (IL-10) cytokines, whereas the HM group did not. These findings suggest that a disturbance in the balance of inflammatory cytokines IL-6 and IL-8 with the anti-inflammatory cytokine, IL-10, combined with the high levels of IL-6 and viral load, characterize possible mechanisms related to the formation of HM.

Therapeutic responses to different anti-Trypanosoma cruzi drugs in experimental infection by benznidazole-resistant parasite stock

SUMMARY This study describes the role of parasite clearance time induced by benznidazole, fexinidazole and posaconazole treatments upon mice infection with a benznidazole-resistant Trypanosoma cruzi strain in the pathological outcomes. Trypanosoma cruzi-infected mice were treated with different drugs and parasite clearance time was detected by blood and tissue qPCR, to determine the dynamic relationship between the efficacy of the treatments and the intensity of heart lesion/serum inflammatory mediators. Our results indicate that anti-T. cruzi treatments were able to reduce parasite replication and consequently induce immunomodulatory effects, where the degree of the immunopathology prevention was related to the time of parasite clearance induced by different treatments. Nevertheless, in benznidazole and posaconazole treatments, parasite rebounding was detected with parasitism reaching levels similar to infected and non-treated mice; the time for parasitic rebound being earlier among benznidazole-treated mice. In parallel, an increase of cardiac lesions and plasma chemokine levels was also detected and was more accentuated in benznidazole-treated animals. Interestingly, in the presence of parasitological cure (fexinidazole treatment), basal levels of these inflammatory mediators were evidenced as well as an absence of cardiac inflammation or fibrosis. Overall, our data indicate that all treatments have positive effects on the clinical evolution of T. cruzi infection, with success in preventing cardiac alterations being drug-dependent.

Real-time PCR strategy for parasite quantification in blood and tissue samples of experimental Trypanosoma cruzi infection

The lack of an accurate diagnosis has been a serious obstacle to the advancement of the anti-Trypanosoma cruzi chemotherapy and long-term infection can result in different health risks to human. PCRs are alternative methods, more sensitive than conventional parasitological techniques, which due to their low sensitivities are considered unsuitable for these purposes. The aim of this study was to investigate a sensitive diagnostic strategy to quantify blood and cardiac tissues parasites based on real-time PCR tools during acute and chronic phases of murine Chagas disease, as well as to monitor the evolution of infection in those mice under specific treatment. In parallel, fresh blood examination, immunological analysis and quantification of cardiac inflammation were also performed to confront and improve real-time PCR data. Similar profiles of parasitemia curves were observed in both quantification techniques during the acute phase of the infection. In contrast, parasites could be quantified only by real-time PCR at 60 and 120 days of infection. In cardiac tissue, real-time PCR detected T. cruzi DNA in 100% of infected mice, and using this tool a significant Pearson correlation between parasite load in peripheral blood and in cardiac tissue during acute and chronic phases was observed. Levels of serum CCL2, CCL5 and nitric oxide were coincident with parasite load but focal and diffuse mononuclear infiltrates was observed, even with significant (p<0.05) reduction of parasitism after 60 days of infection. Later, this methodology was used to monitor the evolution of infection in animals treated with itraconazole (Itz). Itz-treatment induced a reduction of parasite load in both blood and cardiac muscle at the treatment period, but after the end of chemotherapy an increase of parasitism was detected. Interestingly, inflammatory mediators levels and heart inflammation intensity had similar evolution to the parasite load, in the group of animals treated. Taken together, our data show that real-time PCR strategy used was suitable for studies of murine T. cruzi infection and may prove useful in investigations involving experimental chemotherapy of the disease and the benefits of treatment in relation to parasitism and inflammatory response.

Screening of Brazilian medicinal plants for antiviral activity against rotavirus

ETHNOPHARMACOLOGICAL RELEVANCE

Brazilian medicinal plants traditionally used for the treatment of diarrhoea were investigated for their in vitro antiviral activity against the simian rotavirus SA11.

MATERIALS AND METHODS

The ethanolic crude extracts of plants collected in the cerrado of Minas Gerais, Brazil were submitted to phytochemical screening. The cytotoxicity of the extracts was inferred by cellular morphologic alterations. Antiviral activity was assessed by the ability of the extracts to inhibit the cytopathic effect (CPE) of rotavirus on the treated cells. RT-PCR was performed to confirm and/or confront antiviral assay data.

RESULTS

The maximum non-toxic concentration ranged from 50 to 500 μg/mL. All extracts were toxic at a concentration of 5000 μg/mL but no extract showed cytotoxicity at 50 μg/mL. The species Byrsonima verbascifolia, Myracrodruon urundeuva, Eugenia dysenterica and Hymenaea courbaril exhibited the strongest in vitro activity against rotavirus. Their extracts prevented the formation of CPE, and RT-PCR analysis detected no amplification of genetic material from rotavirus. Tannins, flavonoids, saponins, coumarins and terpenes were the major classes of natural products found in the leaf extracts that showed antiviral activity.

CONCLUSION

Among the species studied, Byrsonima verbascifolia, Eugenia dysenterica, Hymenaea courbaril and Myracrodruon urundeuva showed potential activity against rotavirus and are worthy of further study. The present study corroborates ethnopharmacological data as a valuable source in the selection of plants with antiviral activity and to some extent validates their traditional uses.

Natural vertical transmission by Stegomyia albopicta as dengue vector in Brazil

The mosquito Stegomyia albopicta is among the most important arbovirus vectors in the world, particularly for Dengue viruses. Their natural history suggests that biologically these viruses are highly adapted to their mosquito hosts and they were most likely mosquito viruses prior to becoming adapted to lower primates and humans. As well as being maintained by transmission among susceptible humans, Dengue viruses may also be maintained by vertical transmission in mosquitoes during inter-epidemic periods. The larvae and mosquitoes of Stegomyia albopicta were used to identify the vertical transmission of the dengue virus in nature and to confirm the vectorial capacity concerning the Dengue virus type 2 infection. The minimum infection rate concerning S. albopicta infection with the Dengue virus was 1:36.45. In Brazil this was the first time that high minimum infection rates of vertical transmission of S. albopicta were detected in this species.

Dengue virus 3 genotype 1 associated with dengue fever and dengue hemorrhagic fever, Brazil

Dengue serotype 3 viruses were isolated from patients in Brazil from 2002 through 2004. On the basis of phylogenetic analyses, these isolates were assigned genotype 1. This genotype had never been reported in South America before. Its appearance indicates a major risk factor for dengue epidemics and severe disease.