Occurrence of arbovirus infections in two riverine populations in the municipality of Humaitá, Amazonas, Brazil.

BACKGROUND: The riverine communities of the Amazon comprise different social groups that inhabit the rural areas on the banks of rivers and lakes. Residents usually travel by river to rural and urban areas and are then exposed to urbanized diseases such as those caused by arbovirus infection. In Brazil, emerging diseases such as dengue, Zika, chikungunya, and those caused by infection with Oropouche and Mayaro viruses necessitate epidemiological surveillance. This study was aimed at determining the frequency of positivity for immunoglobulin (Ig)G and IgM antibodies against Zika, chikungunya, and dengue viruses and performing molecular analyses to detect viral RNA for the Zika, chikungunya, dengue virus, Oropouche, and Mayaro viruses, in the same serum samples obtained from riverside populations. METHODS: This cross-sectional study was conducted in a riverside population in the Humaitá municipality of the Brazilian Amazon. More than 80% of the local population participated in this study. Entomological samples were collected to identify local mosquito vectors. RESULTS: Analysis of 205 human serological samples revealed IgG antibodies against the dengue virus in 85 individuals. No molecular positivity was observed in human samples. Entomological analyses revealed 3,187 Diptera species, with Mansonia being the most frequent genus. Aedes aegypti and Aedes albopictus were not detected in the two collections. CONCLUSIONS: IgG antibodies against the dengue virus were highly prevalent, suggesting previous exposure. The absence of the arbovirus vectors Aedes aegypti and Aedes albopictus in the samples supports the hypothesis that the infections recorded likely occurred outside the riverside communities investigated.

Occurrence of arbovirus infections in two riverine populations in the municipality of Humaitá, Amazonas, Brazil

ABSTRACT Background: The riverine communities of the Amazon comprise different social groups that inhabit the rural areas on the banks of rivers and lakes. Residents usually travel by river to rural and urban areas and are then exposed to urbanized diseases such as those caused by arbovirus infection. In Brazil, emerging diseases such as dengue, Zika, chikungunya, and those caused by infection with Oropouche and Mayaro viruses necessitate epidemiological surveillance. This study was aimed at determining the frequency of positivity for immunoglobulin (Ig)G and IgM antibodies against Zika, chikungunya, and dengue viruses and performing molecular analyses to detect viral RNA for the Zika, chikungunya, dengue virus, Oropouche, and Mayaro viruses, in the same serum samples obtained from riverside populations. Methods: This cross-sectional study was conducted in a riverside population in the Humaitá municipality of the Brazilian Amazon. More than 80% of the local population participated in this study. Entomological samples were collected to identify local mosquito vectors. Results: Analysis of 205 human serological samples revealed IgG antibodies against the dengue virus in 85 individuals. No molecular positivity was observed in human samples. Entomological analyses revealed 3,187 Diptera species, with Mansonia being the most frequent genus. Aedes aegypti and Aedes albopictus were not detected in the two collections. Conclusions: IgG antibodies against the dengue virus were highly prevalent, suggesting previous exposure. The absence of the arbovirus vectors Aedes aegypti and Aedes albopictus in the samples supports the hypothesis that the infections recorded likely occurred outside the riverside communities investigated.

Nondestructive Methods of Pathogen Detection: Importance of Mosquito Integrity in Studies of Disease Transmission and Control.

Mosquitoes are vectors of many pathogens, including viruses, protozoans, and helminths, spreading these pathogens to humans as well as to wild and domestic animals. As the identification of species and the biological characterization of mosquito vectors are cornerstones for understanding patterns of disease transmission, and the design of control strategies, we conducted a literature review on the current use of noninvasive and nondestructive techniques for pathogen detection in mosquitoes, highlighting the importance of their taxonomic status and systematics, and some gaps in the knowledge of their vectorial capacity. Here, we summarized the alternative techniques for pathogen detection in mosquitoes based on both laboratory and field studies. Parasite infection and dissemination by mosquitoes can also be obtained via analyses of saliva- and excreta-based techniques or of the whole mosquito body, using a near-infrared spectrometry (NIRS) approach. Further research should be encouraged to seek strategies for detecting target pathogens while preserving mosquito morphology, especially in biodiversity hotspot regions, thus enabling the discovery of cryptic or new species, and the determination of more accurate taxonomic, parasitological, and epidemiological patterns.

Influence of meteorological and seasonal parameters on the activity of Culicoides paraensis (Diptera: Ceratopogonidae), an annoying anthropophilic biting midge and putative vector of Oropouche Virus in Rondônia, Brazilian Amazon.

Biting midges of the genus Culicoides are insects of proven medical and veterinary importance, because of their role in the transmission of viruses, bacteria, protozoa and nematodes. Culicoides paraensis has been considered the main vector of the Oropouche Virus (OROV) in the urban cycle of the disease in the neotropics. Due to the great abundance of Culicoides spp. in the State of Rondônia and its epidemiological history of OROV, we investigated the biting activity in humans, the abundance as a function of meteorological parameters and seasonality, and the detection of OROV. Entomological collections occurred in three municipalities from Brazilian State of Rondônia: Porto Velho, Ariquemes, and Ouro Preto do Oeste. GLMM's were used to determine if Culicoides spp. abundance was predicted by seasonal, diurnal, and meteorological factors. Total RNA was extracted from insects and viral RNA detection was performed using the S segment as the target region of OROV via RT-qPCR. In total, 7315 individuals were captured and identified as C. paraensis. In the dry season, 1488 individuals (24.5%) were recorded, 4591 (75.5%) in the rainy season, with peaks of biting activity between 4pm and 6pm. All variables showed a significative effect on the midge abundance. The rainy season, temperature between 30 °C and 32 °C and relative air humidity between 75% and 85% were the main predictive parameters for capturing the highest average number of insects. Our results confirm diurnal activity of C. paraensis and its greatest abundance in rainy periods. No sample was positive for the OROV, which could be explained by the virus absence in local human populations, C. paraensis as a minor vector species in the sampled localities, and probable low rate of infection of biting midges. Our findings on hourly and seasonal biting activities can provide support to intervention actions regarding vector control and surveillance of this species. This was the first study to collect and analyze biting midges in a region where human OROV cases had already been detected, but without previous information on entomovirological surveillance.

Arbovirus detection in synanthropic mosquitoes from the Brazilian Amazon and in mosquito saliva using Flinders Technology Associates cards.

Although arbovirus transmission and identifying target vectors may provide a baseline for planning disease control strategies, there are many gaps in knowledge regarding these mosquitoes and viral species in urban, rural, or sylvatic habitats in the Brazilian Amazon. Our goal was to screen for dengue, chikungunya, and Zika viruses in synanthropic mosquitoes and with Flinders Technology Associates (FTA) cards using insect saliva. Mosquitoes were caught using ovitraps and aspirators in the city of Porto Velho, Rondônia, Brazil. Honey-baited FTA cards were placed in mosquito cages for 15 days; whole mosquitoes and FTA cards were analysed for viral RNA using RT-qPCR assays. One pool of Aedes aegypti females was found to be infected with the Zika virus and one male mosquito was infected with dengue-4, suggesting natural vertical/venereal transmission. Our study also reported evidence of vertical/venereal transmission of ZIKV in Culex quinquefasciatus males for the first time in the Brazilian Amazon, and the feasibility of using FTA cards to detect arboviruses in the saliva of field-collected mosquitoes. Vertical/venereal transmission of viruses by atypical mosquito species reinforces the need for combined viral and entomological screening in arbovirus surveillance programs.

Anopheline diversity in urban and peri-urban malaria foci: comparison between alternative traps and seasonal effects in a city in the Western Brazilian Amazon.

BACKGROUND: Continuous vector surveillance and sustainable interventions are mandatory in order to prevent anopheline proliferation (or spread to new areas) and interrupt malaria transmission. Anopheline abundance and richness were evaluated in urban and peri-urban malaria foci at a medium-sized city in the Brazilian Amazon, comparing the protected human landing catch technique (PHLC) and alternative sampling methods over different seasonal periods. Additional information was assessed for female feeding behaviour and faunal composition. METHODS: Anophelines were sampled bimonthly in four urban and peri-urban sites in the city of Porto Velho, state of Rondônia, Brazil. The average number of captured mosquitoes was compared between an PHLC (gold standard), a tent trap (Gazetrap), and a barrier screen by means of generalized linear mixed models (GLMM), which also included season and environment (peri-urban/urban) as predictors. RESULTS: Overall, 2962 Anopheles individuals belonging to 12 species and one complex were caught; Anopheles darlingi represented 86% of the individuals. More mosquitoes were captured in the peri-urban setting, and the urban setting was more diverse. The model estimates that significantly more anophelines were collected by PHLC than by the Screen method, and Gazetrap captured fewer individuals. However, the Screen technique yielded more blood-engorged females. The peak hours of biting activity were from 6 to 7 p.m. in urban areas and from 7 to 8 p.m. in peri-urban areas. CONCLUSIONS: Although peri-urban settings presented a greater abundance of anophelines, Shannon and Simpson diversities were higher in urban sites. Each technique proved to be useful, depending on the purpose: PHLC was more effective in capturing the highest anopheline densities, Gazetrap caught the greatest number of species, and the barrier screen technique captured more engorged individuals. There was no seasonal effect on Anopheles assemblage structure; however, a more diverse fauna was caught in the transitional season. Biting activity was more intense from 6 to 8 p.m., with a predominance of An. darlingi.

Acute Chagas Disease Caused by Trypanosoma cruzi TcIV and Transmitted by Panstrongylus geniculatus: Molecular Epidemiological Insights Provided by the First Documented Autochthonous Case in Rondônia, Southwestern Amazonia, Brazil.

Recurrent outbreaks of oral infection and isolated cases characterize the new epidemiological scenario of Chagas disease (CD) in the Brazilian Amazon. Acute Chagas disease (ACD) is common in Pará and Amazonas, Northeastern and Northwestern Brazilian Amazonia. In the present study, we describe the first molecularly characterized autochthonous case of ACD in Rondônia, Southwestern Amazonia. The patient, a 39-year-old male resident in the small city of Cujubim, presented typical ACD symptoms: fever, asthenia, myalgia, progressive dyspnea, swelling of the legs, and tiredness at minimal efforts, all compatible with ACD and indicative of cardiac involvement. A thick blood drop test revealed trypomastigote forms of Trypanosoma cruzi genotyped as TcIV. An epidemiological investigation ruled out oral infection, and support for vectorial transmission included the finding of Panstrongylus geniculatus positive for T. cruzi (TcIII and TcIV) inside the tent used by the patient when harvesting forest timber, and a circular cutaneous lesion resembling a chagoma of inoculation. Treatment with benznidazole led to blood parasite clearance as confirmed by molecular tests. Altogether, our findings fitted well into the ecological scenario where deforestation and colonization of forested areas represent an important risk factor to the adaptation of P. geniculatus to human habitats, favoring vectorial transmission of CD in the Amazonian region.

Sexual Proportion and Egg Hatching of Vector Mosquitos in an Atlantic Forest Fragment in Rio de Janeiro, Brazil.

Some Aedinii mosquitoes are of high importance in the transmission of the sylvatic YFV. Usually, their eggs are very resistant and depend on the rain for their hatching. The present study evaluated the effect of multiple mosquito-egg immersions and the sex ratio of male and female specimens from Atlantic Forest remnants in the state of Rio de Janeiro, Brazil. Three sampling sites were selected in the municipality of Casimiro de Abreu, where 50 ovitraps were randomly installed to collect eggs from the ground level up to different heights, from August 2018 to December 2020. The mosquito sex ratios were compared between seasons and forest sites, using the generalized linear mixed model (GLMM), which included sampling months and trees as random effects. A total of 33,091 mosquito eggs were collected, of which 6152 eggs were already hatched (18%) and 26,939 were unhatched; of these, approximately 76% subsequently hatched. We found that 25% of the eggs corresponded to four species: Aedes albopictus (n = 1277), Ae. terrens (n = 793), Haemagogus janthinomys (n = 89), and Hg. leucocelaenus (n = 3033). The sex ratio (male:female) was variable concerning the sampling sites and the season. For most species, GLMM estimates found no difference in the variation of the average sex ratio as a function of these predictors, and there was no evidence of temporal autocorrelation in the mosquito data. The number of immersions necessary for hatching the eggs differed between mosquito species, and eggs collected in the dry season hatched both in the first immersions and the subsequent events. Co-occurrence of Aedes terrens and Hg. leucocelaenus was the most frequently observed pairwise species combination. Considering recurrent arbovirus outbreaks in Brazil and their burden on the human population, our study helps to shed light on how these vectors behave in nature; therefore, they can be used in surveillance programs.

Rhodnius spp. infestation in palm trees and natural infection by Trypanosoma cruzi and Trypanosoma rangeli in periurban and rural areas of state of the Rondônia, in the Brazilian Amazon.

The state of Rondônia in the Brazilian Amazon is prone to diseases transmitted by insect vectors because of the environmental and population changes resulting from large hydroelectric projects and the expansion of agricultural and livestock industries. The first case of Chagas disease by vectorial transmission was recorded in 2019 in a rural area in Rondônia, reinforcing the need for entomological surveillance. Hence, our goal was to estimate the abundance of Rhodnius spp. in palm trees located in rural and periurban areas and in Brazil-Bolivia border regions, perform domiciliary searches, and check for possible associations between triatomines and the presence/absence of palm-inhabiting fauna and outdoor farming, domestic animals, and buildings. The sampling took place in five municipalities of Rondônia in 2014 (June to August) and 2015 (April to June). Triatomines were collected by active searches during the selective pruning of palm tree crowns. Domiciliary inspections lasted from 30 to 60 min. A set of captured triatomines was analyzed for Trypanosoma cruzi and T. rangeli infection by PCR. Overall, 496 insects were captured during sampling of 150 palms in rural areas and 150 in periurban areas. No triatomine was found during active searches of 59 dwelling either indoors or outdoors. The majority of triatomines caught in the palm trees were identified as Rhodnius robustus (98.6%), and seven specimens were R. pictipes. Triatomine infestation was observed in only 20% of the sampled palms (61/300) in the vicinity of 26/59 households. Nearly half of the infested palm trees had only one or two triatomines, and few palms presented more than 15 triatomines. The municipality of Buritis had the highest triatomine abundance and percentage of infested palms; however, the highest triatomine density per infested palm was observed in Alvorada D'Oeste, where a quarter of the palms were infested. Ants, arachnids, termites, reptiles, and rodents were frequently found in palm trees. Dogs were the predominant domestic animals in households, whereas hens and cattle were the main farming animals. Model estimates showed that the number of triatomines was affected by the presence of henhouses and varied strongly between localities. No relationships were detected between the average number of triatomines and palm fauna and/or palm height. Overall, approximately half of the triatomines were infected with T. cruzi (51.4%) and/or T. rangeli (47.2%), reinforcing the need for continuous entomological surveillance and implementation of community-based approaches because the Brazilian state of Rondônia borders areas experiencing reinfestation by domiciled species and potential colonization of animal shelters by triatomines.

Survey of sand flies (Diptera: Psychodidae: Phlebotominae) in Guajará-Mirim State Park forest reserve, near the Brazil-Bolivian border, with a description of Pintomyia fiocruzi, a new sand fly species.

Rondônia State has been subject to a higher percentage of deforestation than any other Brazilian state in the Amazon basin. Rondônia's protected forests are extremely important because their biodiversity attests to the species richness that has been lost to human encroachment. Phlebotomine sand flies are Leishmania vectors that have the potential to function as environmental bioindicators. A sand fly survey was conducted near the Brazil-Bolivian border, in a protected ombrophylous forest in Guajará-Mirim State Park, which is located between the municipalities of Guajará-Mirim and Nova Mamoré, in Rondônia State, Brazil. A total of 6,341 specimens were collected and 59 species were identified; the most abundant species were Trichophoromyia auraensis (Mangabeira), Nyssomyia antunesi (Coutinho) and Trichophoromyia ubiquitalis (Mangabeira). Additionally, a new sand fly species of the genus Pintomyia (Lima) was discovered and is described herein. This new species belongs to the Pifanomyia Ortiz Scorza subgenus, Serrana group, and is characterized by parameres with a basal area that is clearly more dilated than the apical area. The high diversity and abundance of sand fly vectors observed in this study, such as Ny. antunesi, Th. auraensis and Th. ubiquitalis, indicate that these species are probable vectors within Rondônia State. In addition, the discovery of a new Pintomyia species increases the number of sand fly species in Rondônia to 136, which demonstrates that high sand fly diversity within the region holds great potential for yielding important new discoveries.

Composition and Vertical Stratification of Phlebotomine Sand Fly Fauna and the Molecular Detection of Leishmania in Forested Areas in Rondônia State Municipalities, Western Amazon, Brazil.

This study examined sand fly diversity and the natural infection of sand flies by Leishmania in three localities in Rondônia State: Santo Antônio and São Vicente farm, which are anthropized environments, and the Jamari FLONA, which has not been anthropized. Sand flies were collected in canopies and at ground level using CDC light traps and BG-Sentinel CO2 traps. Female sand flies were grouped into pools that were subjected to DNA extraction and the samples were subjected to PCR to detect and identify Leishmania. A total of 6696 specimens were examined and 52 species were identified. Abundance was greater in canopies than at ground level (n = 5657 and n = 1039, respectively); however, fauna composition was more diverse at ground level. A total of 4870 specimens were collected using CDC light traps and 1826 specimens were collected using BG-Sentinel traps. The presence of Leishmania DNA was detected in 12 pools, and Leishmania species profiles were identified in three of these pools: one pool of Psychodopygus amazonensis and one pool of Psychodopygus chagasi infected with Le. (Vi.) braziliensis, and one pool of Psychodopygus davisi infected with Le. (Le.) amazonensis. Sand flies are sensitive to environmental modification and species diversity is greater in regions that have experienced less anthropization. Although the annual infection rate of cutaneous leishmaniasis is high in Rondônia State, the role that sand flies play in the leishmaniasis transmission cycle remains poorly understood. The high abundance of Ps. davisi and Trichophoromyia auraensis and the presence in these species of natural infection by Leishmania spp. suggest that these species are acting as vectors of tegumentary leishmaniasis in Rondônia.

Understory host plant and insect gall diversity changes across topographic habitats differing in nutrient and water stress in the Brazilian Amazon rainforest / Riqueza de insetos galhadores associados a habitats de sub-bosque com diferentes topografias e níveis de estresse hídrico e nutricional em uma floresta da Amazônia Central, Brasil

ABSTRACT Topographic gradients in terra firme forests are associated with pronounced changes in soil texture, soil nutrients and distance to the water-table, thereby creating different hydric and nutritional conditions for plants and their associated herbivore community. The aim of this study was to investigate galling species and host plant richness and gall species composition across topographic habitats differing in nutrient and water stress in the Brazilian Amazon rainforest. Nineteen 250 x 3 m plots were randomly sampled in the valley, slope, plateau-slope transition, and plateau habitats in terra firme forests. All individual dicotyledonous plants 1 to 3 meters high were examined for the presence of insect galls. Galling species and host plant richness differed significantly among the studied habitats and were higher in slope habitats (drier habitats), as expected. More humid areas (valleys) showed the lowest richness of galling species, and a lower number of understory host plants. PERMANOVA and PERMDISP results demonstrated that the gall species composition differed significantly in the valley, slope, plateau-slope transition, and plateau areas. However, these structural differences in species composition could be due to unequal dispersion of variability among forest habitats. Our data suggested that spatial heterogeneity, such as a mosaic of local water status and nutrient availability resulting from the topographic conditions, can affect host plants and their associated galling insects.

RESUMO As variações topográficas encontradas nas florestas de terra firme são acompanhadas por fortes mudanças no conteúdo de argila e concentração de nutrientes do solo, criando, portanto, diferentes condições hídricas e nutricionais para plantas e as comunidades de herbívoros associadas. O objetivo do presente estudo foi avaliar a riqueza e composição de espécies de insetos galhadores e suas plantas hospedeiras ao longo de um gradiente topográfico com habitats que diferem quanto ao estresse hídrico e nutricional. Dezenove parcelas de 250 x 3 m foram estabelecidos aleatoriamente em habitats de vertente, platô, transição platô-vertente e baixio, claramente distintos em áreas de terra firme. Todas as dicotiledôneas com 1 a 3 metros de altura foram examinadas quanto à presença de galhas de insetos. As galhas encontradas foram coletadas e insetos galhadores foram classificados em morfoespécies. A riqueza de galhadores e de plantas hospedeiras diferiram significativamente entre os habitats estudados, e como esperado, foi maior no habitat de vertente. As áreas mais úmidas (baixios) apresentaram menor riqueza de plantas hospedeiras no sub-bosque e, conseqüentemente, um número menor de espécies de galhadores. Os resultados das análises de PERMANOVA e PERMDISP demonstraram que a composição da espécie de insetos galhadores variou significativamente entre as áreas de floresta de terra firme. No entanto, essas diferenças estruturais na composição das espécies podem ser devidas à dispersão desigual da variabilidade entre os habitats. Nossos dados sugerem que a heterogeneidade espacial, tal como o mosaico de status hídrico e nutricional do solo associado às condições topográficas, pode afetar plantas hospedeiras e insetos galhadores associados.

Anthropic effects on sand fly (Diptera: Psychodidae) abundance and diversity in an Amazonian rural settlement, Brazil.

Sand flies (Diptera: Psychodidae) are responsible for the transmission of protozoan parasites that cause leishmaniases. They are found predominantly in forests, but some species exploit environments that have been subject to deforestation and subsequent human colonization. Studies conducted in Brazil over the past 30 years show that some species are adapting to peri-urban and urban settings. We evaluated sand fly diversity and abundance in the rural settlement of Rio Pardo, Presidente Figueiredo Municipality, Amazonas State, Brazil. Settlement households were divided into four categories. These categories were determined by the human population density and the degree of deforestation in the immediate area. We used CDC light traps to sample the area surrounding 24 households (6 households in each category). Samples were taken on six occasions during September-November 2009 and June-August 2010. A total of 3074 sand fly specimens were collected, including 1163 females and 1911 males. These were classified into 13 genera and 52 species. The greatest abundance of sand flies and the greatest richness of species were observed in areas where human population density was highest. Our results show that changes in the human occupancy and vegetation management in rural settlements may affect the population dynamics and distribution of sand fly species, thereby affecting the local transmission of cutaneous leishmaniases.

Comparison of the performance of two spontaneous sedimentation techniques for the diagnosis of human intestinal parasites in the absence of a gold standard.

Performance evaluation of diagnostic tests is critical in the search for accurate diagnoses. A gold standard test is usually absent in parasitology, thus rendering satisfactory assessment of diagnostic accuracy difficult. Moreover, reliability (assessed by the study of repeatability) is a rarely studied characteristic of diagnostic tests. This study compared and evaluated the performance (repeatability, concordance and accuracy) of the spontaneous sedimentation technique (SST) and the Paratest for the diagnosis of Giardia lamblia, Entamoeba histolytica complex, Blastocystis spp., Ascaris lumbricoides, hookworm, Trichuris trichiura and Calodium hepaticum. Fecal samples of 143 individuals were separated into three replicates for each test. Concordance and homogeneity of the results between replicates of each test and between tests were evaluated. Proportions of positives, sensitivity and specificity were estimated using a Bayesian Latent Class Model. High repeatability of both tests was found for the detection of intestinal parasites, except for Blastocystis spp. and hookworm. Concordance between tests was generally high (concordance correlation coefficient, 0.72-0.88), except for Blastocystis spp., hookworm and T. trichiura. The Paratest detected more cases of Blastocystis spp. and fewer of hookworm than the SST. The tests were quite discordant in the detection of T. trichiura. A low sensitivity (39.4-49.2% for SST, 35.8-53.8% for Paratest) and a high specificity (93.2-97.2%) were found for both tests. The Paratest presented a slightly higher sensitivity for the diagnosis of Blastocystis spp. (53.8%), and SST did so for hookworm (49.2%). This is the first study on repeatability and accuracy (using a Bayesian approach) of two spontaneous sedimentation techniques. These results suggest underdiagnosis of little dense parasitic forms due to technical limitations in both tests. We conclude that the combined study of repeatability, concordance and accuracy is a key strategy for better evaluation of the performance of tests and is also useful for the identification of technical limitations.

Calodium hepaticum: household clustering transmission and the finding of a source of human spurious infection in a community of the Amazon region.

BACKGROUND: Calodium hepaticum (syn. Capillaria hepatica) is a worldwide helminth parasite of which several aspects of transmission still remain unclear. In the Amazon region, the mechanism of transmission based on the ingestion of eggs present in the liver of wild mammals has been suggested as the cause of the spurious infections described. We performed an epidemiological investigation to determine the incidence, risk of spurious infection and the dynamics of transmission of C. hepaticum in a community of the Brazilian Amazon. METHODOLOGY/PRINCIPAL FINDINGS: Stool samples of 135 individuals, two dog feces and liver tissue from a peccary (captured and eaten by the residents) were analyzed by conventional microscopy. Dog feces were collected from the gardens of households presenting human cases of spurious C. hepaticum infections. Community practices and feeding habits related to the transmission of the parasite were investigated. The individual incidence of spurious infection was 6.7% (95% CI: 2.08-11.24). Cases of spurious infection were observed in 7.5% of the families and the household incidence was from 50% to 83.3%. The risk of spurious infection was 10-fold greater in persons consuming the liver of wild mammals (p = 0.02). The liver tissue of a peccary and one feces sample of a dog presented eggs of C. hepaticum. The consumption of the infected liver was the cause of the spurious infections reported in one household. CONCLUSIONS/SIGNIFICANCE: This is the first identification of a source of spurious infection by C. hepaticum in humans and we describe a high rate of incidence in household clusters related to game liver alimentary habits. The finding of a dog feces contaminating peridomiciliary ground suggests the risk of new infections. We conclude that the mechanism of transmission based on the ingestion of liver is important for the dynamics of transmission of C. hepaticum in the studied area.

Diversity of galling insects in Styrax pohlii (Styracaceae): edge effect and use as bioindicators.

Impacts of forest fragmentation and edge effect on plant-herbivores interactions are relatively unknown, and the relationships between galling insects and their host plants are very susceptible to environmental variations. The goal of our study was to test the edge effect hypothesis for galling insects associated with Styrax pohlii (Styracaceae) host plant. Samplings were conducted at a fragment of semi-deciduous forest in Goiânia, Goiás, Brazil. Thirty host plant individuals (15 at fragment edge and 15 in its interior) were sampled in July of 2007; in each plant, 10 apical branches were collected at the top, middle and bottom crown levels. Our results supported the prediction of greater richness of gall morphotypes in the edge habitat compared with remnant interior. In a similar way, gall abundance and frequency of attacked leaves were also greater in the fragment edge. These findings consequently suggest a positive response of galling insect diversity to edge effect; in the Saint-Hilaire forest, this effect probably operates through the changes in microclimatic conditions of edge habitats, which results in an increased hygrothermal stress, a determinant factor to distribution patterns of galling insects. We also concluded that these organisms could be employed as biological indicators (i) because of their host-specificity, (ii) they are sensitive to changes in plant quality, and (iii) present dissimilar and specific responses to local variation in habitat conditions.