Systematics of the Jaguar catfish genus Liosomadoras Fowler, 1940 (Auchenipteridae: Siluriformes)

Liosomadoras Fowler, 1940 includes two nominal species: L. oncinus, described from the rio Negro in Brazil, and L. morrowi described from the Peruvian Amazon. Both species are known from only few specimens deposited in fish collections, and information on these fishes is scarce. In order to rectify this situation, diagnoses of the genus and its species and an osteological description off.. oncinus are presented based on recently collected specimens. In addition, the taxonomy of the species of Liosomadoras is reviewed, and L. morrowi is confirmed as distinct from L. oncinus, and also distributed in the Brazilian Amazon. Liosomadoras is hypothesized as a relatively basal genus within Auchenipterinae, sister to all other species of the group, except Asterophysus batrachus and Tocantinsia piresi.

Amazonian malaria: Asymptomatic human reservoirs, diagnostic challenges, environmentally driven changes in mosquito vector populations, and the mandate for sustainable control strategies

Across the Americas and the Caribbean, nearly 561,000 slide-confirmed malaria infections were reported officially in 2008. The nine Amazonian countries accounted for 89% of these infections; Brazil and Peru alone contributed 56% and 7% of them, respectively. Local populations of the relatively neglected parasite Plasmodium vivax, which currently accounts for 77% of the regional malaria burden, are extremely diverse genetically and geographically structured. At a time when malaria elimination is placed on the public health agenda of several endemic countries, it remains unclear why malaria proved so difficult to control in areas of relatively low levels of transmission such as the Amazon Basin. We hypothesize that asymptomatic parasite carriage and massive environmental changes that affect vector abundance and behavior are major contributors to malaria transmission in epidemiologically diverse areas across the Amazon Basin. Here we review available data supporting this hypothesis and discuss their implications for current and future malaria intervention policies in the region. Given that locally generated scientific evidence is urgently required to support malaria control interventions in Amazonia, we briefly describe the aims of our current field-oriented malaria research in rural villages and gold-mining enclaves in Peru and a recently opened agricultural settlement in Brazil. (C) 2011 Elsevier B.V. All rights reserved.

Trends, drivers and impacts of changes in swidden cultivation in tropical forest-agriculture frontiers: A global assessment

This meta-analysis of land-cover transformations of the past 10-15 years in tropical forest-agriculture frontiers world-wide shows that swidden agriculture decreases in landscapes with access to local, national and international markets that encourage cattle production and cash cropping, including biofuels. Conservation policies and practices also accelerate changes in swidden by restricting forest clearing and encouraging commercial agriculture. However, swidden remains important in many frontier areas where farmers have unequal or insecure access to investment and market opportunities, or where multi-functionality of land uses has been preserved as a strategy to adapt to current ecological, economic and political circumstances. In some areas swidden remains important simply because intensification is not a viable choice, for example when population densities and/or food market demands are low. The transformation of swidden landscapes into more intensive land uses has generally increased household incomes, but has also led to negative effects on the social and human capital of local communities to varying degrees. From an environmental perspective, the transition from swidden to other land uses often contributes to permanent deforestation, loss of biodiversity, increased weed pressure, declines in soil fertility, and accelerated soil erosion. Our prognosis is that, despite the global trend towards land use intensification, in many areas swidden will remain part of rural landscapes as the safety component of diversified systems, particularly in response to risks and uncertainties associated with more intensive land use systems. (C) 2011 Elsevier Ltd. All rights reserved.

Ontogenetic Variation in Ammonia Excretion during the Early Life Stages of the Amazon River Prawn, Macrobrachium amazonicum

Dry mass (DM) and total ammonia-N (TAN) excretion were determined in embryos, larvae (ZI-ZIX, Z = zoea ), and postlarvae (PL) at 1, 7, and 14 d after metamorphosis (PL1, PL7, and PL14) of Macrobrachium amazonicum. Animals in postmolt-intermolt (A-C) stages were sorted according to their developmental stages, and placed into incubation chambers (similar to 30 mL) for 2 h to quantify TAN excretion. After this period, analyses were carried out using Koroleff`s method for TAN determination. Individual TAN excretion generally increased throughout ontogenetic development and varied from 0.0090 +/- 0.0039 mu g TAN/individual/h in embryo to 1.041 +/- 0.249 mu g TAN/individual/h in PL14. There was no significant difference between embryo-ZIV and ZV-ZIX (P > 0.05), whereas PL1, PL7, and PL14 differed (P < 0.05) from each other. Higher increments in individual ammonia-N excretion were observed between ZIV-ZV, PL1-PL7, and PL7-PL14. Mass-specific excretion rates presented two groups, embryo-ZII (P > 0.05) and ZIII-PL14 (P > 0.05). The lowest value was found in embryo (0.17 +/- 0.07 mu g TAN/mg DM/h) and the maximum values in ZV and PL1 (0.65 +/- 0.25 and 0.64 +/- 0.27 mu g TAN/mg DM/h, respectively). Results indicate that metabolic rate is proportional to the body mass in M. amazonicum, during early life stages. Variations in ammonia excretion during this phase may be associated mainly with body size. Data obtained in the present study may be useful in developing and optimizing rearing techniques of M. amazonicum, such as the proportions between biofilter and rearing tank size, and stocking density in culture tanks or in transport bags.

Growth parameters and mortality rate of the Scomber japonicus peruanus (Jordan & Hubb, 1925) along the Peruvian coast, South Pacific

The growth parameters and the mortality rates of the Scomber japonicus peruanus (Chub mackerel) were studied based on monthly data of frequency of fork length classes obtained from commercial landings off the Peruvian coast from 1996 to 1998. The asymptotic body length and growth rate values obtained by the ELEFAN I (Electronic Length Frequency Analysis) ranged from 40.20 cm to 42.20 cm and from 0.38 to 0.39, respectively. The oscillation amplitude was 0.60; the Winter point values varied from 0.50 to 0.60 and the performance index from 2.79 to 2.84. The total mortality rate of the Chub mackerel obtained by the linearized catch curve oscillated between 1.68 and 3.35. The rate of fishing mortality varied from 1.16 to 2.78 and the exploitation rate from 0.68 to 0.84. The annual rate of natural mortality estimated by the Pauly`s method ranged from 0.52 to 0.53. The results obtained allow us to conclude that the longevity of the Chub mackerel was slightly over seven years.

Mercury toxicity in Amazon gold miners: Visual dysfunction assessed by retinal and cortical electrophysiology

Amazonian gold mining activity results in human exposure to mercury vapor. We evaluated the visual system of two Amazonian gold miners (29 and 37 years old) by recording the transient pattern electroretinogram (tPERG) and transient pattern visual evoked potential (tPVEP). We compared these results with those obtained from a regional group of control subjects. For both tPERG and tPVEP, checkerboards with 0.5 or 2 cycles per degree (cpd) of spatial frequency were presented in a 16 degrees squared area, 100% Michelson contrast, 50cd/m(2) mean luminance, and 1 Hz square-wave pattern-reversal presentation. Two averaged waveforms (n = 240 sweeps, Is each) were monocularly obtained for each subject in each condition. Both eyes were monocularly tested only in gold miners. Normative data were calculated using a final pooled waveforin with 480 sweeps. The first gold miner, LCS, had normal tPERG responses. The second one, RNP, showed low tPERG (P50 component) amplitudes at 0.5cpd for both eyes, outside the normative data, and absence of response at 2 cpd for his right eye. Delayed tPVEP responses (P 100 component) were found at 2 cpd for LCS but the implicit times were inside the normative data. Subject RNP also showed delayed tPVEP responses (all components), but only the implicit time obtained with his right eye was outside the normative data at 2cpd. We conclude that mercury exposure levels found in the Amazon gold miners is high enough to damage the visual system and can be assessed by non-invasive electrophysiological techniques. (C) 2007 Elsevier Inc. All rights reserved.

A new, brightly colored species of Pseudoboa Schneider, 1801 from the Amazon Basin (Serpentes, Xenodontinae)

A new species of Pseudoboa, P. martinsi, is described from the Amazon basin of Brazil, with records from the states of Para, Amazonas, Roraima and Rondonia. The new species is distinguished from the other five species of the genus by a combination of scalation and coloration characters. Individuals of the new species were found in both primary and disturbed forested areas. The species seems to be predominantly nocturnal and secretive because specimens were found foraging in the litter during night.

A NEW GENUS AND SPECIES OF CAMAENID FROM THE AMAZON RAINFOREST, BRAZIL (PULMONATA, HELICOIDEA)

Olympus nimbus, new genus and species, is described for the Amazon Rainforest, collected at Neblina Peak, Amazonas, Brazil. The taxon is clearly related to the camaenid genus Solaropsis because of conchological and anatomical attributes. However, the new taxon differs from its allies mainly in its smaller size (about 15 mm), its tall spire (almost as tall as wide), its narrow umbilicus, in lacking a bursa copulatrix diverticulum and a clear penial epiphallus, and by its complex internal penial organization. This paper also discusses the state of current knowledge of the South American Camaenidae.

Review of the genus Microphilypnus Myers, 1927 (Teleostei: Gobioidei: Eleotridae) from the lower Amazon basin, with description of one new species

Microphilypnus Myers, 1927 is a genus with three nominal species (M. amazonicus and M. macrostoma from the lower Amazon basin, and M. ternetzi from Orinoco), and is among the most poorly studied groups of Neotropical fishes. In this paper, M. ternetzi and M. macrostoma are redescribed and validated and M. amazonicus is regarded as synonym of M. ternetzi. Also, a new species, M. acangaquara, is described from the lower Amazon.

Are biological species and higher-ranking categories real? Fish folk taxonomy on Brazil`s Atlantic Forest coast and in the Amazon

Analysis of Brazilian fishers` classifications of 24 marine (Atlantic coast) and 24 freshwater (Amazon) fish species reveals that fishers from the Atlantic coast identify fish mainly through generic names (primary lexemes), while riverine Amazonian fishers typically identify them through binomials. The similarity of Amazonian fish species seems to contribute to the detailed folk taxonomy used by riverine fishers. High-ranking groups called ""relatives"" or ""cousins"" are sorted by fishers in terms of similarities of habitat, diet, and morphology and, secondarily, behavior. The general correspondence between the folk and scientific taxonomies reinforces the reality of both the supracategories used by these fishers and the biological groups as discontinuities in nature. Given the urgency of biological inventories and the lack of knowledge of high-biodiversity environments such as the Atlantic Forest and the Amazon, these results suggest that fisher knowledge and experience could contribute to scientific research.

Plasmodium vivax Duffy binding protein: baseline antibody responses and parasite polymorphisms in a well-consolidated settlement of the Amazon Region

Objective To investigate risk factors associated with the acquisition of antibodies against Plasmodium vivax Duffy binding protein (PvDBP) a leading malaria vaccine candidate in a well-consolidated agricultural settlement of the Brazilian Amazon Region and to determine the sequence diversity of the PvDBP ligand domain (DBPII) within the local malaria parasite population. Methods Demographic, epidemiological and clinical data were collected from 541 volunteers using a structured questionnaire. Malaria parasites were detected by conventional microscopy and PCR, and blood collection was used for antibody assays and molecular characterisation of DBPII. Results The frequency of malaria infection was 7% (6% for P. vivax and 1% for P. falciparum), with malaria cases clustered near mosquito breeding sites. Nearly 50% of settlers had anti-PvDBP IgG antibodies, as detected by enzyme-linked immunosorbent assay (ELISA) with subjects age being the only strong predictor of seropositivity to PvDBP. Unexpectedly, low levels of DBPII diversity were found within the local malaria parasites, suggesting the existence of low gene flow between P. vivax populations, probably due to the relative isolation of the studied settlement. Conclusion The recognition of PvDBP by a significant proportion of the community, associated with low levels of DBPII diversity among local P. vivax, reinforces the variety of malaria transmission patterns in communities from frontier settlements. Such studies should provide baseline information for antimalarial vaccines now in development.

Holocenic proxies of sedimentary organic matter and the evolution of Lake Arari-Amazon Region

Four sediment cores were sampled from Lake Arari, located on Marajo Island at the mouth of the Amazon River. The island's vegetation cover is composed mainly of Amazon coastal forest, herbaceous and varzea vegetation. The integration of data on sedimentary structures, pollen, carbon and nitrogen isotope records, C/N ratios and radiocarbon ages allowed the identification of changes in vegetation and the sources of organic matter accumulated in the lake during the Holocene. The data indicate a relatively high flow energy, marine water influence and the presence of mangroves during the lagoon phase between 8990 and 8690 cal yr B.P. and 2310-2230 cal yr B.P. Between 2310 and 2230 cal yr B.P. and similar to 1000 cal yr B.P., the flow energy decreased and the mangroves were replaced by herbaceous vegetation following the decline in marine influence, likely due to the increase in freshwater river discharge. During the last 1000 years, Lake Arari was established in association with the expansion of herbaceous vegetation and the dominance of freshwater algae. (C) 2011 Elsevier BM. All rights reserved.

Prevalence of hepatitis B virus infection and carriage after nineteen years of vaccination program in the Western Brazilian Amazon

Introduction: Reductions in the prevalence of hepatitis B virus (HBV) infection and carriage, decreases in liver cancer incidence, and changes in patterns of liver dysfunctions are described after hepatitis B vaccination. Methods: We conducted a population-based seroprevalence study aimed at estimating the HBV prevalence and risk of infection in the rural area of Labrea following nineteen years of HBV vaccination. Results: Half of the subjects showed total anti-HBc of 52.1% (95% CI 49.6-54.7). The HBsAg prevalence was 6.2% (95% CI 5.1-7.6). Multivariate analysis showed an inverse association between HBV infection and vaccination (OR 0.62; 95% CI 0.44-0.87). HBsAg remained independently associated with past hepatitis (OR 2.44; 95% CI 1.52-3.89) and inversely to vaccination (OR 0.43; 95% CI 0.27-0.69). The prevalence of HBeAg among HBsAg-positive individuals was 20.4% (95% CI 12.8-30.1), with the positive subjects having a median age of 11 years (1-46) p=0.0003. Conclusions: We demonstrate that HBV infection is still an important public health issue and that HBV vaccination could have had better impact on HBV epidemiology. If we extrapolate these findings to other rural areas in the Brazilian Amazon, we can predict that the sources of chronic infected patients remain a challenge. Future studies are needed regarding clinical aspects, molecular epidemiology, surveillance of acute cases, and risk groups.

HEV infection in swine from Eastern Brazilian Amazon: Evidence of co-infection by different subtypes

Hepatitis E virus (HEV) is a fecal-orally transmitted member of the genus Hepevirus that causes acute hepatitis in humans and is widely distributed throughout the world. Pigs have been reported as the main source of genotypes 3 and 4 infection to humans in non-endemic areas. To investigate HEV infection in pigs from different regions of Para state (Eastern Brazilian Amazon), we performed serological and molecular analyses of serum, fecal and liver samples from 151 adult pigs slaughtered between April and October 2010 in slaughterhouses in the metropolitan region of Belem, Para. Among the animals tested, 8.6% (13/151) were positive for anti-HEV IgG but not for anti-HEV IgM. HEV RNA was detected in 4.8% (22/453) of the samples analyzed and 9.9% (15/151) of the animals had at least one positive sample. Phylogenetic analysis showed that all sequences belonged to genotype 3 that were related to human isolates from other non-endemic regions, suggesting that the isolates had zoonotic potential. Subtypes 3c and 3f were simultaneously detected in some pigs, suggesting co-infection by more than one strain and/or the presence of a recombinant virus. These results constitute the first molecular and serologic evidence of swine HEV circulation in the Eastern Brazilian Amazon. (C) 2012 Elsevier Ltd. All rights reserved.

Micronucleus frequency in children exposed to biomass burning in the Brazilian Legal Amazon region: a control case study

Background: The Amazon represents an area of 61% of Brazilian territory and is undergoing major changes resulting from disorderly economic development, especially the advance of agribusiness. Composition of the atmosphere is controlled by several natural and anthropogenic processes, and emission from biomass burning is one with the major impact on human health. The aim of this study was to evaluate genotoxic potential of air pollutants generated by biomass burning through micronucleus assay in exfoliated buccal cells of schoolchildren in the Brazilian Amazon region. Methods: The study was conducted during the dry seasons in two regions of the Brazilian Amazon. The assay was carried out on buccal epithelial cells of 574 schoolchildren between 6-16 years old. Results: The results show a significant difference between micronucleus frequencies in children exposed to biomass burning compared to those in a control area. Conclusions: The present study demonstrated that in situ biomonitoring using a sensitive and low cost assay (buccal micronucleus assay) may be an important tool for monitoring air quality in remote regions. It is difficult to attribute the increase in micronuclei frequency observed in our study to any specific toxic element integrated in the particulate matters. However, the contribution of the present study lies in the evidence that increased exposure to fine particulate matter generates an increased micronuclei frequency in oral epithelial cells of schoolchildren.