Assessment of fish assemblages in streams of different orders in the Upper Paraná River basin, Central Brazil

The aim of this study was to test whether the richness observed and the biomass per trophic group of fish assemblages vary depending on the order (1st and 2nd) of the streams located in three different basins of the Upper Paraná River Basin, Central Brazil. Samples were collected between April and September, 2009, in 27 streams of the Meia Ponte, Piracanjuba and Santa Maria River basins. A total of 4,879 specimens were collected distributed in 59 species and 19 families. The statistical analyses carried out indicate that the observed richness and biomass of omnivore fish were influenced by the interaction of two factors: stream order and basin. The 2nd order streams located in the Santa Maria basin presented significant differences in the observed richness and omnivore biomass when compared to i) 1st order streams in the same basin (only richness) or in the Piracanjuba and Meia Ponte basin; ii) 2nd order streams in the Piracanjuba (only omnivore biomass) and Meia Ponte Rivers basins. Results are discussed considering the influence of geomorphic processes on fish assemblages and food availability.

A survey of planorbid molluscs in the Amazonian region of Brazil

A survey of the plarnorbid fauna in the Brazilian states of the Amazonian river basin revealed the occurence of 14 species, 8 of the genus Biomphalaria, 4 of Drepanotrema, 1 of Antillorbis and 1 of Plesiophysa, besides a naturalized puopulation of Helisoma duryi at Santa Rosa, municipality of Formosa, state of Goiás. The following is the distribution of the species by genera, in decreasing order of frequency (number of localities in parenthesis): 1. Biomphalaria straminea (50): Acre, Amazonas, Distrito Federal, Goiás, Maranhão, Mato Grosso, Mato Grosso do Sul, Pará and Roraima; 2. B. occidentalis (30): Acre, Amazonas, Mato Grosso and Mato Grosso do Sul; 3. B. schrammi (22); Distrito Federal, Goiás, Maranhão, Mato Grosso, Mato Grosso do Sul and Pará; 4. B. amazonica (14): Acre, Amazonas and Rondônia; 5. B. glabrata (13): Distrito Federal, Goiás, Maranhão and Pará; 6. B. peregrina (4): Distrito Federal, Goiás and Mato Grosso do Sul; 7. B. tenagophila (2): Distrito Federal and Goiás; 8. B. oligoza (2): Mato Grosso do Sul; 9. Drepanotrema lucidium (72): Acre, Amapá, Amazonas, Distrito Federal, Goiás, Maranhão, Mato Grosso, Mato Grosso do Sul, Pará, Rondônia and Roraima; 10. D. anatinum (41): Acre, Amazonas, Distrito Federal, Goiás, Maranhão, Mato Grosso do Sul, Pará, Rondônia and Roraima; 11. D. depressissimum (19): Acre, Amazonas, Distrito Federal, Goiás, Maranhão, Mato Grosso, Mato Grosso do Sul and Pará; 12. D. cimex (15): Acre, Amazonas, Distrito Federal, Goiás, Mato Grosso, Mato Grosso do Sul and Pará; 13. Antillorbis nordestensis (3): Distrito Federal, Maranhão and Pará; 14. Plesiophysa ornata (1): Goiás. B. glabrata is responsibel for transmission of schistosomiasis mansoni in northeastern Pará, northern Marnhão and central Goiás including the Distrito Fedreal. B. tenagophila, although susceptible to experimental infection with Schistosoma mansoni, has not been found naturally infected so far in the area. B. straminea has been incriminated as...

A rewiew of the subgenus Trichopygomyia Barretto, 1962; with description of a new species from the brazilian Amazon Basin (Diptera: Psychodidae, Phlebotominae)

The subgenus Trichopygomyia Barreto, 1962 of the phlebotomine genus Lutzomyia França, 1924 is reviewed. This subgenus corresponds to the informal species group longispina of Theodor (1965). Lutzomyia (Trichopygomya) ratcliffei n.sp. from the Brazilian Amazon Basin is described. Figures, keys, distribution maps and notes on ecology are presented for all the known forms. The better known species are most frequently encountered in armadillo burrows and, therefore, could well be vectors of Leishmania.

A new sand fly in the subgenus Nyssomyia (Diptera, psychodidae) from the Amazon basin of Brazil

Lutzomyia (Nyssomyia) waltoni m.sp., uma nova espécie de flebótomo é descrita e ilustrada. Observações ecológicas disponíveis são apresentadas. (AU)

A pilot study to control Lutzomyia umbratilis (Diptera: Psychodidae), the major vector of Leishmania brazileiensis guyanensis, in a peri-urban rainforest of Manaus, Amazonas State, Brazil

In the second half of 1980, 112 (or ca. 16%) of the inhabitants of the new settlement of São José, city of Manaus, contracted cutaneous leishmaniasis whilst clearing their properties of terra firme rainforest. With the aid of SUCAM, the authors carried out a pilot study to investigate the feasibility of reducing populations of Lutzomyia umbratilis, the local silvatic vector of Leishmania braziliensis guyanensis, by spraying insecticide on its favoured diurnal resting sites, the bases of the larger forest trees. Most manvector contact is at these resting sites and, therefore, it was encouraging to record a marked reduction of the tree-base populations of L. umbratilis for 21 days following just one application of D.D.T. emulsion in an area 200m square. Most of the treated trunks were not occupied by L. umbratilis for at least eleven months. Suggestions for extending the pilot study are made, and the need for collaboration with a clinical team is emphasized. Leishmania b. guyanensis is the aetiological agent of [quot ]pain bois[quot ], which is hyperendemic from French Guiana to central Amazônia. In the absence of proven vaccines or methods of vector control, some simple methods for limiting transmission of Le. b. guyanensis to man are listed.

Lymnaea columella: two new Brazilian localities in the states of Amazonas and Bahia

The occurrence of Lymnaea columella is recorded in Tefé, Amazonas state, where it was found together with Drepanotrema anatinum, Physa marmorata and pomacea sp. L. columella was also collected in Salvador, Bahia state, at the dique do Tororó, an urban lake formely mentioned (as "lac Baril") by Moricand (1853) as a breeding-place of Biomphalaria glabrata, Drepanotrema cimex, D. depressissimum, Pomacea lineata, P. decussata and Ancylus moricandi. The four first-mentioned species, as well as physa cubensis and Hemisinus brasiliensis, were also collected now. This is the first record of a lymnaeid in the Northeastern region of Brazil.

Lutzomyia reducta Feliciangeli et al., 1988, a host of Leishmania amazonensis, sympatric with two other members of the Flaviscutellata complex in southern Amazonas and Rondônia, Brazil (Diptera: Psychodidae)

A member of the Lutzomyia flaviscutellata complex from Rondônia and southern Amazonas States, Brazil, is so close to the Venezuelan Lutzomyia olmeca recuta Feliciangeli et al., 1988, that it is regarded as belonging to the same species. Since this phlebotomine co-extis with L. olmeca nociva in Brazil, the subspecific status of the former is untenable and is rased to specific rank, as Lutzomyia reducta. The Brazilian material is described and illustrated, and compared with specimens of L. o. nociva and L. flaviscutellata from the same area. Keys to the known taxa of the flaviscutellata complex are presented. Leishmania amazonensis was isolated from one heavily infected specimen of L. reducta, making this the third species of the flaviscutellata complex to be implicated as a vector of this parasite in Brazil. The relative abundance of the three sympatric flaviscutellata complex species varies locally and appears to be related to soil drainage. L. reducta constituted about 25% if all phlebotomines captured in Disney traps at poorly drained and well drained site, but appears not to coloniza areas subject to periodic flooding. L. olmeca nociva was restricted to poorly drained areas not subject to flooding, whereas L. flaviscutellata was ubiquitous L. reducta has never been detected north of the Amazon river in Brazil, but absence of recosrds from western and northwestern Amazonas State may reflect lack of collecting in these areas.

Effects of immigration on the prevalence of malaria in rural areas of the Amazon basin of Brazil

Epidemiological studies were conducted on malaria in three rural areas of the Amazon basin in the State of Rondônia: the town of Costa Marques, Forte Príncipe da Beira (Fort), and an immigrant settlement in the nearby forest. These studies were instituted to document the malaria problem and to describe the role of immigration on its distribution and prevalence. Hospital records in the town show that the number of malaria cases increased five fold from 1983 to 1987 and that the predominant malaria parasite changel from Plasmodium vivax to P. falciparum. Increased malaria followed increased immigration and colonization of the forest. A series of epidemiologic studies suggested the linkage between malaria and immigration as the prevalence of malaria was 1-2% at the Fort, a stable community, 8-9% at Costa Marques, a growing community, and 14-26% in the new settlements in the forest.

Analog Modelling of N-S anticlines of the External Sierras (Jaca basin, Southern Pyrenees)

Report for the scientific sojourn carried out at the Uppsala Universitet, Sweden, from April to July the 2007. Two series of analogue models are used to explore ductile-frictional contrasts of the basal décollement in the development of oblique and transverse structures simultaneously to thin-skinned shortening. These models simulate the evolution of the Central External Sierras (Southern Pyrenees, Spain), which constitute the frontal emerging part of the southernmost Pyrenean thrust sheet. They are characterized by the presence of transverse N-S to NW-SE anticlines, which are perpendicular to the Pyrenean structural trend and developed in the hangingwall of the Santo Domingo thrust system, detaching on an unevenly distributed Triassic materials (evaporitic-dolomitic interfingerings). Model setup performs a décollement made by three patches of silicone neighbouring pure brittle sand. Model series A test the thickness ratio between overburden and décollement. Model series B test the width of frictional detachment areas. Model results show how deformation reaches further in areas detached on ductile layer whereas frictional décollement areas assimilate the strain by means of an additional uplift. This replicates the structural style of Central External Sierras: higher structural relief of N-S anticlines with regard to orogen-parallel structures, absence of a representative ductile décollement in the core, tilting towards the orogen and foreland-side closure not thrusted by the frontal emerging South-Pyrenean thrust.

A new species of Amphisbaena from the state of Amazonas, Brasil (Reptilia, Amphisbaenia, Amphisbaenidae)

Amphisbaena hugoi, sp. n., from the site of the Balbina hydroelectric dam, in the state of Amazonas (01º53'S, 59º28'W), is sufficiently characterized by having (one specimen known): 4 preanal pores; 225 body annuli; 36 tail annuli, with autotomy constriction on the 13th annulus, 16 dorsal and 18 ventral segments to a midbody annulus; body color patter a brown back and a white belly, clearly demarcated, anteriorly at the level of the lateral sulcus, posteriorly one and then two scales below it, with a thin light line on the lateral sulcus, a white cap on the head, dorsally extending onto the neck; autotomy annulus ventrally brown-colored.

Ecological aspects of nematode parasites of introduced salmonids from Valdivia river basin, Chile

Between 1986 and 1987 fishes distributed among the following species introduced in Chile, and from different sectors of the Valdivia river basin (39º30' - 40º00', 73º30' - 71º45'W), were examined: 348 Salmo trutta, 242 Salmo gairdneri, 24 Cyprinus carpio and 52 Gambusia affinis holbrooki. The presence of Camallanus corderoi and Contracaecum sp. in S. gairdneri and of C. corderoi in S. trutta is recorded in Chile for the first time. Cyprinus carpio and G. a. holbrooki did not present infections by nematodes. The prevalence and mean intensity of the infections by nematodes presented significant differences among some sectors of the Valdivia river basin. In general, the prevalence and intensity of the infections by C. corderoi were greater than those by Contracaecum sp. The infections in S. gairdneri were higher than in S. trutta. The sex of the hosts had no influence on the prevalence and intensity of the infections by both nematodes. The length of the hosts did have an influence, except in the case of the infections by Contracaecum sp. in S, gairdneri. The infrapopulations of both nematode species showed over dispersion in most cases. The diet of the examined salmonids suggests that they would become infected principally throught the consuption of autochthonous fishes.

Vector incrimination and effects of antimalarial drugs on malaria transmission and control in the Amazon Basin of Brazil

World ecosystems differ significantly and a multidisciplinary malaria control approach must be adjusted to meet these requirements. These include a comprehensive understanding of the malaria vectors, their behavior, seasonal distribution and abundance, susceptibility to insecticides (physiological and behavioral), methods to reduce the numbers of human gametocyte carriers through effective health care systems and antimalarial drug treatment, urban malaria transmission versus rural or forest malaria transmission, and the impact of vaccine development. Many malaria vectors are members of species complexes and individual relationship to malaria transmission, seasonal distribution, bitting behavior, etc. is poorly understood. Additionaly, malaria patients are not examined for circulating gametocytes and both falciparum and vivax malaria patients may be highly infective to mosquitoes after treatment with currently used antimalarial drugs. Studies on the physiological and behavioral effects of DDT and other insecticides are inconclusive and need to be evalusted.