Differences in richness and composition of gastrointestinal parasites of small rodents (Cricetidae, Rodentia) in a continental and insular area of the Atlantic Forest in Santa Catarina state, Brazil.

The first and only study on gastrointestinal parasites of wild rodents in the Island of Santa Catarina was done in 1987. The aim of this study was to identify intestinal parasites from wild rodents in Santo Amaro da Imperatriz and Santa Catariana Island, and to compare the richness and composition of the gastrointestinal parasite community of both areas. Rodents were captured with live traps, and feces were screened using the sedimentation method and optical microscopy. The following species of rodents were captured in the two areas: Akodon montensis, Euryoryzomys russatus, Oligoryzomys nigripes and Nectomys squamipes. In Santo Amaro da Impetratriz, prevalent parasites were: A. montensis (51%), E. russatus (62%), O. nigripes (53%) and N. squamipes (20%). From the Island of Santa Catarina the rodent prevalence rates were: A. montensis (43%), E. russatus (59%), O. nigripes (30%) and N. squamipes (33%) and the collected parasites were: Hymenolepis sp., Longistriata sp., Strongyloides sp., Hassalstrongylus sp., Syphacia sp., Trichomonas sp., Ancylostomidae, Trichuridae, Oxyuridae and Eucoccidiorida. The species richness (10.6 ± 0.7) of the endoparasite comunity in the area located on the continent was higher (p < 0.01) and different (p = 0.001) from that of the area located on the island (6.9 ± 0.5).

[A new species of the oliveirai complex (new designation for matogrossensis complex) from the State of Rio Grande do Sul, Brazil]. / Nova espécie do complexo oliveirai (nova denominação para o complexo matogrossensis) (Hemiptera, Reduviidae, Triatominae) do estado do Rio Grande do Sul, Brasil.

The authors describe a new species of Triatominae (Hemiptera, Reduviidae) from the State of Rio Grande do Sul, Brazil. The study was made with specimens captured in basaltic formations, at an average altitude of 750 m.o.s.l. The new species is included in the oliveirai complex together with other four species T. williami, T. matogrossensis, T. guazu and T. jurbergi). The new species was compared with the most similar one, T. oliveirai, from which the main differences are on the proportions of head, ante and postocular regions, the general color pattern and the male genitalia, specially on the median process of the pygophore, the support of phallosome, the vesica and the process of the endosome.

Trypanosoma cruzi infection in Didelphis marsupialis in Santa Catarina and Arvoredo Islands, southern Brazil.

Between 1984 and 1993 the prevalence of the Trypanosoma cruzi infection in opossums (Didelphis marsupialis) was studied in Santa Catarina and Arvoredo Islands, State of Santa Catarina, Brazil. The association of the triatomine bug Panstrongylus megistus with opossums nests and the infection rate of these triatomines by T. cruzi was also studied. Thirteen different locations were studied in Santa Catarina Island (SCI), in which 137 D. marsupialis were collected. Sixty two opossums were collected at the Arvoredo Island (AI), located 12 miles north from SCI. All captured animals were submitted to parasitological examinations that revealed the presence of T. cruzi in 21.9% of the opossums captured in SCI and 45.2% among opossums captured in the AI. The presence of P. megistus was detected in most of the D. marsupialis nests collected in the SCI, however, in the non-inhabited AI only eight triatomines were collected during the whole study. The presence of T. cruzi-infected D. marsupialis associated with P. megistus in human dwellings in the SCI, and the high infection rate of D. marsupilais by T. cruzi in the absence of a high vector density are discussed.

Characterization of Leishmania sp. strains isolated from autochthonous cases of human cutaneous leishmaniasis in Santa Catarina State, southern Brazil.

Four Leishmania sp. samples were isolated from autochthonous human cases of American cutaneous leishmaniasis (ACL) in Santa Catarina State, southern Brazil. These strains were characterized using indirect immunofluorescence with a panel of Leishmania-specific monoclonal antibodies (MAbs), and by PCR amplification and hybridization assay of the mini-exon gene with group specific probes. The results obtained with the MAbs were in agreement with the genetic marker. Two isolates (MHOM/BR/89/JSC89-H1 and MHOM/BR/89/JSC89-H2) were identified as L. (Leishmania) amazonensis and two (MHOM/BR/96/LSC96-H3 and MHOM/BR/97/LSC97-H4) as L. (Viannia) braziliensis. The southernmost autochthonous cases of ACL in Brazil are due to two different Leishmania sp. species, confirming the spreading of ACL on the American continent.

Elimination of bancroftian filariasis (Wuchereria bancrofti) in Santa Catarina state, Brazil.

During the 1950s, three foci of Wuchereria bancrofti transmission were identified in the State of Santa Catarina, Brazil. In Florianópolis, São José da Ponta Grossa and Barra da Laguna community treatment of bancroftian filariasis with diethylcarbamazine (DEC) was performed using two distinct approaches, without vector control or improvements in sanitation. In two of the three communities only microfilaraemic individuals were treated, while in Barra da Laguna the entire population received DEC treatment regardless of their infection status. In both cases, transmission of the parasite was blocked and no new cases were detected in all localities for up to 10 years. Recently, a new survey in São José da Ponta Grossa and Barra communities revealed no microfilaria-positive individuals, including residents that were positive in the 1950s. These data confirm that transmission of W. bancrofti was interrupted in Santa Catarina, and mass treatment appears to be more effective than treatment of microfilaraemic individuals only.

Population biology of Rhodnius domesticus Neiva & Pinto, 1923 (Hemiptera: Reduviidae) under laboratory conditions.

The entire life cycle of Rhodnius domesticus, fed weekly on mice, was studied under controlled conditions. Aspects related to hatching, life time, mortality, feeding behaviour and fecundity for each stage of the insect life-cycle were evaluated. The hatching rate observed in 100 eggs was 57% and the mean time of hatching was 15.6 days. Forty-six nymphs (80.7%) completed the cycle and the mean time from NI to adult was 93.8 days. The average span in days for each stage was 12.4 for NI, 9.8 for NII, 14.2 for NIII, 16.8 for NIV and 25.0 NV. the number of bloodmeals in each nymphal stage varied from 1 to 3. The mortality rate was 12.3% for NI, 3.5% for NII and 1.7% for NIII and NV nymphs. The mean number of eggs laid per female in a 9-month period was 333.1. Average adult survival rates were 287.6 + 133 and 328 + 73 days for males and females respectively.

Characterization of trypanosomes from the subgenus Schizotrypanum isolated from bats, Eptesicus sp. (Chiroptera: Vespertilionidae), captured in Florianópolis, Santa Catarina State, Brazil.

Seven Trypanosoma spp. isolates obtained from bats (Eptesicus sp.) were characterized using experimental infection in mice, triatomines, and culicines; complement lysis; indirect fluorescence assays; as well as isoenzyme and random-amplified polymorphic DNA (RAPD) profiles. The Trypanosoma sp. isolates were compared with Trypanosoma cruzi, Trypanosoma rangeli. and 2 other bat trypanosomes species, Trypanosoma vespertilionis and Trypanosoma hastatus. Trypanosoma sp. isolates were different from the other species in all experiments, except in complement lysis. Experimental infection of triatomines and culicines with Trypanosoma sp. proved to be transitory. These parasites were noninfective for both normal and immunosuppressed mice. Isoenzyme and RAPD profiles obtained for Trypanosoma sp. were quite distinct from T. cruzi and T. rangeli and closely related to T. vespertilionis and T. hastatus. No cross-reaction was observed between sera from mice infected with Trypanosoma sp. and the other trypanosomatids and vice-versa. Trypanosoma sp. induced no protection against T. cruzi infection in mice. The very low, or nonsimilarity between Trypanosoma sp. isolates and the other species used in this study suggests that they might be members of a distinct bat trypanosome species. However, further studies should be done to prove their affinities with Trypanosoma cruzi-marinkellei, another trypanosome species from bats.

Besnoitia sp. (Protozoa:Toxoplasmatinae) from Akodon montensis (Rodentia:Cricetidae) in Santa Catarina State, Brazil.

Tissue cysts of Besnoitia sp. were found in muscles and several organs from a naturally infected Akodon montensis captured in the rural area of the municipality of Timbó, Santa Catarina State, in southern Brazil. Indirect fluorescence and enzyme-linked immunosorbent assays carried out with sera from mice chronically infected with Toxoplasma gondii and Besnoitia sp. showed, as expected, a stronger reaction against homologous than heterologous antigens. No cross-protection was observed in mice immunized with T. gondii when challenged with Besnoitia sp. This is the first description of a natural infection of A. montensis by parasites of the genus Besnoitia sp. in Brazil.

Evasão em Engenharia Química: opiniões de discentes, docentes e evadidos

O objetivo desta pesquisa foi avaliar as variáveis do processo de evasão do primeiro ano do Ciclo Básico de um curso de Engenharia Química. Em um primeiro instante, com base na definição de evasão como sendo a saída do aluno da Universidade, por qualquer motivo, exceto a diplomação, buscou-se verificar o índice de evasão dos ingressantes no período diurno, entre 1994 e 1995. Foram identificados ainda os evadidos do diurno (GAD), grupos dos alunos do noturno (GAN), grupo dos evadidos do diurno (GED), grupos dos evadidos da noturno (GEN) e, 21 professores que constituem o grupo de docentes. Finalmente foi enviado um questionário aos sujeitos desta pesquisa, o que permitiu coletar dados e opiniões dos alunos evadidos, dos não-evadidos e de professores. De modo geral, a dificuldade financeira aliada ao campo de trabalho e ao gerenciamento da relação estudo-trabalho foram os aspectos motivacionais mais indicados por estes sujeitos, sendo que a divergência observada com o grupo de evadidos do diurno demonstrou que estes sujeitos percebem diferentemente os fatores que determinam a evasão, fato que necessita de mais estudos para ser melhor esclarecido (AU)

Biological and isoenzymatic characterization of Trypanosoma cruzi strains isolated from sylvatic reservoirs and vectors from the state of Santa Catarina, Southern Brazil.

Sixty eight Trypanosoma cruzi strains were isolated in the state of Santa Catarina, Southern Brazil, from sylvatic reservoirs or naturally infected vectors and characterized by their biological behaviour in mice, morphology of bloodstream forms and isoenzyme profiles. Twenty eight strains were isolated from the triatomine bug (Panstrongylus megistus), 2 from rodents (Echimys dasythrix and Akodon sp) and 38 from opossums (Didelphis marsupialis). The infectivity in mice of 48 T. cruzi strains showed that 2 (4.2%) were of high virulence, 19 (39.6%) of medium virulence, 15 (31.2%) of low virulence and 12 (25.0%) produced subpatent parasitemia in mice. A morphological study of bloodstream trypomastigotes from 8 T. cruzi strains showed a predominance of stout forms. The isoenzyme pattern of 59 T. cruzi strains showed that 54 (91.5%) belonged to zymodeme Z1, 3 (5.1%) to zymodeme Z2 and 2 (3.4%) to mixed zymodemes, Z1 and Z2. All 34 T. cruzi strains analyzed from opossums were Z1. Three out of 5 strains isolated from adults of P. megistus collected inside houses, belonged to zymodeme Z2 and two strains exhibited mixed zymodemes, Z1 and Z2, in 5 out of 6 enzymes studied. Although the State of Santa Catarina is a non endemic region for human Chagas'disease, the presence of zymodeme Z2 parasites in the sylvatic vector, P. megistus, captured in domiciliary environments suggests the possibility of human and/or domestic mammal infection by T. cruzi.

Some environmental and biological factors influencing the activity of entomopathogenic Bacillus on mosquito larvae in Brazil

The influence of environmental and biological factors on the efficacy of Bacillus thuringiensis serovar israelensis and B. sphaericus as mosquito larvicides are reviewed. The importance of strain dependence, cultivating media/methods, mosquito species/specificity, formulations and their relation to mosquito feeding habits, as well as temperature, solar exposure, larval density and concomitant presence of other aquatic organisms are addressed with reference to the present status of knowledge in Brazil.

Some environmental and biological factors influencing the activity of entomopathogenic Bacillus on mosquito larvae in Brazil.

The influence of environmental and biological factors on the efficacy of Bacillus thuringiensis serovar israelensis and B. sphaericus as mosquito larvicides are reviewed. The importance of strain dependence, cultivating media/methods, mosquito species/specificity, formulations and their relation to mosquito feeding habits, as well as temperature, solar exposure, larval density and concomitant presence of other aquatic organisms are addressed with reference to the present status of knowledge in Brazil.

Randomly amplified polymorphic DNA (RAPD) and isoenzyme analysis of Trypanosoma rangeli strains.

Sixteen Trypanosoma rangeli strains were compared by isoenzyme and randomly amplified polymorphic DNA (RAPD) analysis. Eight strains were isolated from either Rhodnius prolixus or Homo sapiens from Honduras, Colombia and Venezuela. Another eight strains were isolated from either Panstrongylus megistus or the rodent Echimys dasythrix from the State of Santa Catarina, southern Brazil. All six T. rangeli strains isolated from P. megistus were co-infections with Trypanosoma cruzi, demonstrating an overlap of the sylvatic cycles of these parasites and that the accurate identification of species is of utmost importance. Both isoenzyme and RAPD analysis revealed two distinct groups of T. rangeli strains, one formed by the strains from Santa Catarina and the other, by the strains from Honduras, Colombia and Venezuela. With the five enzymes used, all the strains from Santa Catarina had identical profiles which overlapped with those of the other regions only in the pattern obtained with malic enzyme. Analysis of 138 RAPD bands by means of an unweighted pair group method analysis (UPGMA) phenogram using the Dice similarity coefficient allowed the separation of the two groups based on their divergence at a lower level of similarity than the phenon line. We show that the identification of T. cruzi and T. rangeli in naturally mixed infections is readily achieved by either RAPD or isoenzyme analysis.

[Colonization of artificial ecotopes by Panstrongylus megistus in Santa Catarina Island, Florianópolis, Santa Catarina, Brazil]. / Colonização de ecótopos artificiais pelo Panstrongylus megistus na Ilha de Santa Catarina, Florianópolis, Santa Catarina, Brasil.

The aim of this work was to verify the colonization of Panstrongylus megistus on artificial ecotopes in Florianópolis, in the Santa Catarina Island, South Brazil. For this purpose 443 houses of the Lagoa district and 779 house annexes (524 chicken-houses, 46 corrals and 209 storage-houses) in 9 different places were examined from 1985 to 1992. These ecotopes, which include ceilings and basements, were checked after application of dislodging liquid (Pirisa 5%). Colonization by P. megistus was verified in two houses, three chicken-houses and one storage-house of the Lagoa district, where eggs, nymphs and adults were collected. To verify local reports of P. megistus occurrence, another two houses and one school were investigated. The colonization at all of these places was confirmed. In the 9 artificial ecotopes examined, 559 eggs, 305 nymphs and 24 adults were collected. The infection rate of P. megistus by Trypanosoma cruzi was 55.3% (182/329). A similar infection rate of 56.5% (78/138) was obtained in adults of P. megistus from sylvatic ecotopes and in adults captured in the houses by the inhabitants between 1983 to 1991. Precipitin tests revealed blood from just one source in 94.0% of the insects (170/181). Human blood was found in 80.6% (25/31) of the adults and in 5.8% (1/17) of the nymphs captured in the houses. These results suggest the need to ally serious epidemiologic vigilance to the effort of the inhabitants in order to avoid the risk of domiciliation of P. megistus in the houses.