RESUMO

Between May 2006 and March 2007, 65 water samples were collected from both heated and unheated swimming pools in the city of Porto Alegre, the capital of the Brazilian state of Rio Grande do Sul. The aim was to explore the problem posed by, and the pathogenic potential of, Acanthamoeba in the pools. Free-living amoebae in the samples were isolated by culture with Escherichia coli and identified from trophozoite and cyst morphology and the results of a PCR with Acanthamoeba-specific oligonucleotide primers. Potential pathogenicity was assessed in osmotolerance and thermotolerance assays. Thirteen (20%) of the water samples investigated were found positive for free-living amoebae, all identified as belonging to morphological groups II (nine isolates) or III (four isolates) of the genus Acanthamoeba. All 13 isolates were found positive in the Acanthamoeba-specific PCR, and the results of the tolerance assays indicated that five (38%) of the isolates should be considered potentially pathogenic. The results of this first study on the occurrence and distribution of Acanthamoeba in the water of swimming pools in Porto Alegre confirm the presence of potentially pathogenic types that may present a risk to human health.

Assuntos

RESUMO

Colombian datura virus (CDV) was first described in 1968 (3) and has since been reported in Europe (4), Japan (see 4 for additional references), and the United States (1,2). CDV is a member of the family Potyviridae with flexuous, filamentous nucleocapsids that can be transmitted by mechanical inoculation and grafting and is known to be vectored by the common aphid Myzus persicae. In the fall of 2007, five Brugmansia plants of unknown species from a Parks Board Collection in a Lower Mainland nursery, British Columbia, Canada, were found to be displaying symptoms typical of a viral infection: chlorotic flecking and mottling on leaves, leaf shrivel, and vein banding. Symptomatic leaves from these five plants were tested by ELISA (Immuno Strip Test, Agdia, Elkhart, IN) for several common viruses including Impatiens necrotic spot, Tobacco mosaic, Cucumber mosaic, and Tomato spotted wilt viruses and found to be negative for all. However, rub inoculations onto the herbaceous indicators Nicotiana occidentalis and N. benthamiana resulted in severe symptom formation including necrosis, wilting, shriveling, stunted growth, petiole and stem tip collapse, as well as collapse from the base of the plants, and plant death within 2 weeks after inoculation. A leaf dip assay of the original infected Brugmansia sample and infected N. benthamiana tissue revealed flexuous, potyvirus-like particles with the electron microscope (EM). On the basis of the Brugmansia leaf symptoms and the EM results, a possible infection with CDV was suspected. Primers CDV-3 and CDV-NIb5, specific to CDV (4), were used in a reverse transcription (RT)-PCR assay that amplified an approximate 1,600-bp fragment from the original Brugmansia sample and inoculated N. bentamiana and N. occidentalis plants. The amplified portion of the genome is the extreme 3' terminus and includes the 3' noncoding sequence, the viral coat protein gene, and part of the viral replicase gene. Fragments were cloned into pCR2.1-TOPO (Invitrogen, San Diego, CA) and two clones from each plant (total of six clones) were sequenced in both directions. Sequences of all clones were essentially identical, with only three nucleotide differences among the clones (GenBank Accession No. EU571230). BLASTn analysis revealed the highest match to several CDV isolates ranging from 98.7 to 99.5% nucleotide sequence identity. BLASTp analysis of the 451 amino acid viral polyprotein translation product gave a similarly high match with CDV isolates, with the highest match to a Hungarian isolate of CDV (GenBank Accession No. CAD26690) of 99.8% identity, or only one mismatch out of 451 amino acids. An additional group of 15 large symptomless Brugmansia plants, located approximately 6 m from the five symptomatic plants, were also tested by RT-PCR and found to be positive. These 15 plants were of a different but also unknown species of Brugmansia. In conclusion, analysis of symptomatic Brugmansia from a Canadian collection by transfer of disease to herbaceous indicators, EM, RT-PCR, and genomic sequence comparisons, are consistent with the detection and identification of the potyvirus Colombian datura virus. To our knowledge, this is the first report of this viral pathogen in Canada. References: (1) S. Adkins et al. Phytopathology (Abstr.) 95(suppl.):S2, 2005. (2) C. R. Fry et al. J. Phytopathol. 152:200, 2004. (3) R. P. Kahn and R. Bartels. Phytopathology 58:58, 1968. (4) J. Schubert et al. J. Phytopathol. 154:343, 2006.

RESUMO

Several recombinant clones expressing antigens from Echinococcus granulosus were isolated previously from a parasite cDNA library using cystic hydatid disease (CHD) patients' sera or rabbit hyperimmune antiserum against a lipoproteic fraction from bovine cyst fluid. Six of these antigens were expressed in Escherichia coli and the purified recombinant proteins were tested in enzyme-linked immunosorbent assay (ELISA) for specific IgG with a panel of sera from patients with surgically confirmed (n = 58) or immunologically diagnosed (n = 71) CHD. Sera from clinically normal individuals (n = 203) and sera from individuals with other helminthic infections (n = 65) were assayed for the assessment of specificity. A cut-off value was determined by receiver-operating-characteristic plots for each antigen. A recombinant antigen B subunit (AgB8/2) presented the highest sensitivity (93.1%), considering the group of sera from patients with CHD surgically confirmed, and specificity (99.5%) and is proposed as the basis for an immunodiagnostic test. The other recombinant antigens tested presented sensitivities between 58.6% and 89.7%, and three of them were considered of complementary value. In subclass-specific ELISA, different IgG isotypes showed dominance in the response for each of the recombinant antigens. There was a clear predominance of IgG4 response for all antigens tested, indicating that this would be the subclass of choice to be assessed for these recombinant proteins.

Assuntos

RESUMO

Polymerase chain reaction (PCR)-restriction fragment length polymorphism analysis (PRA) which relies on the amplification of a 439-bp portion of the hsp65 gene present in all mycobacteria, followed by two distinct digestions (with BstEII and HaeIII) of the PCR product, offers a rapid and easy alternative that allows identification of the species without the need for specialized equipment. Wild leprosy in the nine-banded armadillo (Dasypus novemcinctus) is characterized by the presence of multiple bacilli in internal organs such as lymph nodes, spleen and liver, as well as in nerves and skin. We could observe this in 9 out of 132 animals captured in Corrientes, Argentina, an area endemic for leprosy in humans. Mycobacterium leprae were recognized in those naturally infected animals through different techniques. Three samples of extracted DNA of the mycobacteria present in the spleen, liver and popliteal lymph node of a naturally infected animal during the Experimental Program in Armadillo (PEA) and three samples of human lepromas were processed by PRA. The patterns of the six samples analyzed were identical and were characteristic of M. leprae. These studies, made for the first time in Argentina, corroborate the initial discoveries in South America made by our investigative group on the detection of armadillos naturally infected with the Hansen bacillus.

Assuntos

RESUMO

Two different Echinococcus granulosus antigen B subunits (AgB8/1 and AgB8/2) were characterized and the structure of the genes encoding these two proteins were compared. DNA sequences were expressed in Escherichia coli and the antigens' diagnostic value was then assessed. The genomic sequence of AgB8/1 has a 92 bp intron in the position corresponding to amino acid 16; the AgB8/2 genomic sequence presents a 68 bp intron in the position corresponding to amino acid 20. Both introns are located between the putative N-terminal hydrophobic sequence and the secreted peptide. A comparison between the AgB8/1 and AgB8/2 nucleotide sequences showed a 53.5% identity among exons and a 50% identity between introns. According to the molecular diversity analysis, the elapsed time since both genes shared a common ancestor would be around 4.2x10(7) years. When the native AgB and the two recombinant antigens (rAgB8/1 and rAgB8/2) were tested in an anti-IgG ELISA, the sensitivity of the native antigen B was 77.41% and its specificity was 81.9%, while rAgB8/1 showed 54.84% of sensitivity and 80.17% of specificity and rAg138/2 had an 83.87% sensitivity and a 98.28% specificity. Statistical analysis confirms that rAgB8/2 has a better performance than rAgB8/1 and native AgB in ELISA.

Assuntos

RESUMO

A case of caecum nematodiasis is described in a guinea fowl (Numida melagris) from the Municipal Zoo, Presidencia Roque Saenz Peña (Chaco) Argentina. Nematodes obtained from the caecum were observed in optic microscopy. According to their morphometric characteristics and location in the definitive host, were identified as belonging to the family Heterakidae, species Heterakis gallinarum, (Schrank, 1788) Maden, 1949.

Assuntos

RESUMO

A case of gastric nematodiasis is described in a gineafowl (Numida meleagris) from the Municipal Zoo, Presidencia Roque Saenz Peña (Chaco) Argentina. Nematodes obtained from the glandular stomach were observed in optic microscopy. According to their morphometric characteristics and location in the definitive host, were identified as belonging to the family Acuariidae, subfamily Acuariinae, species Dispharynx nasuta Rudolphi, 1819.

Assuntos

RESUMO

The hemolytic activity of five live isolates of Trichomonas gallinae was investigated. The isolates were subsequently tested against the erythrocytes of seven adult animal species. Each of the five isolates tested lysed all human blood groups, as well as rabbit, rat, chicken, horse, bovine, and sheep erythrocytes. No hemolysin released by the parasite could be detected. Our preliminary results suggest that the hemolytic activity is not due to the hemolysin release by T. gallinae or to a product of its metabolism. Pretreatment of live trichomonads with concanavalin A reduced levels of hemolysis by 40%.

Assuntos

RESUMO

The hemolytic activity of live isolates and clones of Trichomonas vaginalis and Tritrichomonas foetus was investigated. The isolates were tested against human erythrocytes. No hemolytic activity was detected by the isolates of T. foetus. Whereas the isolates of T. vaginalis lysed erythrocytes from all human blood groups. No hemolysin released by the parasites could be detected. Our preliminary results suggest that hemolysis depend on the susceptibility of red cell membranes to destabilization and the intervention of cell surface receptors as a mechanism of the hemolytic activity. The mechanism could be subject to strain-species-genera specific variation of trichomonads. The hemolytic activity of T. vaginalis is not due to a hemolysin or to a product of its metabolism. Pretreatment of trichomonads with concanavalin A reduced levels of hemolysis by 40%.

Assuntos

RESUMO

Hemolytic activity of 7 isolates and 2 clones of Trichomonas vaginalis and 1 isolate and 2 clones of Tritrichomonas suis was determined using incubation with erythrocytes. T. vaginalis hemolyzed all human blood groups, and no correlation between pathogenicity and hemolytic activity was observed and no hemolysin released by the parasite could be detected. No hemolytic activity was observed with strains and clones of T. suis against erythrocytes from all blood groups and with swine erythrocytes.

Assuntos

Assuntos

Assuntos