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Memórias do Instituto Oswaldo Cruz, Volume: 97, Número: 4, Publicado: 2002
  • Some Aspects of Protozoan Infections in Immunocompromised Patients: A Review Review

    Ferreira, Marcelo Simão; Borges, Aércio Sebastião

    Resumo em Inglês:

    Protozoa are among the most important pathogens that can cause infections in immunocompromised hosts. These microorganisms particularly infect individuals with impaired cellular immunity, such as those with hematological neoplasias, renal or heart transplant patients, patients using high doses of corticosteroids, and patients with acquired immunodeficiency syndrome. The protozoa that most frequently cause disease in immunocompromised patients are Toxoplasma gondii, Trypanosoma cruzi, different Leishmania species, and Cryptosporidium parvum; the first two species cause severe acute meningoencephalitis and acute myocarditis, Leishmania sp. causes mucocutaneous or visceral disease, and Cryptosporidium can lead to chronic diarrhea with hepatobiliary involvement. Various serological, parasitological, histological and molecular methods for the diagnosis of these infections are currently available and early institution of specific therapy for each of these organisms is a basic measure to reduce the morbidity and mortality associated with these infections.
  • Ecology of Sand Flies (Diptera: Psychodidae: Phlebotominae) in the North of the State of Mato Grosso, Brazil Epidemiology

    Azevedo, Alfredo CR; Souza, Nataly A; Meneses, Cláudio RV; Costa, Wagner A; Costa, Simone M; Lima, José B; Rangel, Elizabeth F

    Resumo em Inglês:

    Peixoto de Azevedo is located in the north of State of Mato Grosso, where environmental alterations led to an outbreak of American cutaneous leishmaniasis in the 80s. The parasite from patients was characterized as Leishmania (V.) braziliensis. The aim of this study is to contribute to the sand fly ecology of Central-West Brazil. Captures were carried out monthly using CDC light traps. Twenty-six species of sand fly were characterized; among which Lutzomyia (Lutzomyia) spathotrichia, L. runoides and L. (Psychodopygus) llanosmartinsi were recorded in the State of Mato Grosso for the first time. L. (Nyssomyia) whitmani, L. (N.) antunesi, L. (L.) spathotrichia, L. (P.) c. carrerai, L. (P.) complexa, L. (P.) lainsoni and L. (N.) umbratilis constituted 92.4% of the local fauna, among which L. (N.) whitmani and L. (N.) antunesi, accounting for about 53% of the fauna at the stations of capture. On the vertical distribution of sand flies on the Beira-Rio Farm, L. (N.) whitmani and L. (N.) antunesi prevailed at ground level and in the canopy, respectively, whereas on the BR-080, L. (P.) llanosmartinsi was prevalent on the ground and L. (P.) c. carrerai, in the canopy. It is suggested that L. (N.) umbratilis is the local vector.
  • Longitudinal Study on the Natural Infection of Biomphalaria straminea and B. glabrata by Schistosoma mansoni in an Endemic Area of Schistosomiasis in Pernambuco, Brazil Epidemiology

    Favre, Tereza C; Pieri, Otávio S; Zani, Luciana C; Ferreira, Jainne M; Domás, Glauce G; Beck, Lilian H; Barbosa, Constança S

    Resumo em Inglês:

    The abundance of snail hosts and the rates of infection with Schistosoma mansoni were monitored monthly for four years in two representative localities subjected to repeated chemotherapy of infected persons. Snail abundance varied from 1.0 to 4.4 collected per person/minute/station for Biomphalaria straminea and from 0.1 to 7.0 for B. glabrata. Infection rates of snails in nature varied from 0% to 15% for the former and from 0% to 70% for the latter species. Human infection increased from 35.5% to 61.9% in the locality occupied by B. straminea, and decreased from 40.3% to 20.8% in that occupied by B. glabrata. No relationship could be detected between human infection and the snail variables. Despite seasonal variations, natural infection persisted throughout the monitoring period in both snail species. It reached remarkably high levels in B. straminea when compared to those obtained by other authors probably because of differences in methodology. It is recommended that longitudinal studies should be carried out focally and periodically to avoid underestimating the prevalence of schistosome infection in snails.
  • Risk Zones of Human Leishmaniases in the Western Mediterranean Basin: Correlations between Vector Sand Flies, Bioclimatology and Phytosociology Epidemiology

    Rispail, Philippe; Dereure, Jacques; Jarry, Daniel

    Resumo em Inglês:

    Correspondence analysis was applied to sand fly sampling in 865 stations from the Western Mediterranean basin. The position of each of 24 species was determined with respect to the bioclimatic belts. Thus, the multidimensional analyses manifest clear correlations between bioclimatic belts and their expression in the area, the phytosociological groupings, and vector species of visceral and cutaneous leishmaniases. The transfer of these data to usual maps allows to delimit the geographical distribution of these diseases in the Western Mediterranean basin and contributes to the determination, in a rational manner, of the high risk zones.
  • IgM-Immunofluorescence Test as a Diagnostic Tool for Epidemiologic Studies of Schistosomiasis in Low Endemic Areas Epidemiology

    Kanamura, Herminia Yohko; Silva, Rita Maria da; Chiodelli, Silvia Gabriel; Glasser, Carmen Moreno; Dias, Luiz Candido de Souza

    Resumo em Inglês:

    The high sensitivity and the ability to diagnose schistosomiasis in a very early phase after infection have indicated the detection of IgM antibodies to Schistosoma mansoni gut antigens by the immunofluorescence test (IgM-IFT) as a useful serological test for epidemiological studies in low endemic areas. When applied in a follow-up study for two years, higher rates of seroconversion from IFT negative to positive were observed during the summer months, suggesting seasonal transmission of schistosomiasis in the rural area of the municipality of Itariri (São Paulo, Brazil). In each survey, blood samples from about 600 schoolchildren were collected on filter paper and submitted to IgM-IFT. When the blood samples were classified for the IgM antibody levels, according to the intensity of fluorescent reaction observed at fluorescence microscopy, and correlated to the egg counts in the Kato-Katz positive patients, no association was observed. This observation might suggest that the intensity of fluorescence observed in the IgM-IFT, as an indicator of IgM antibody levels, could not be an useful seroepidemiological marker for classifying areas of low endemicity according to degrees of infection.
  • Chagas Disease in Dogs from Endemic Areas of Costa Rica Epidemiology

    Montenegro, Victor M; Jiménez, Maurico; Dias, JC Pinto; Zeledón, Rodrigo

    Resumo em Inglês:

    Dogs with the presumptive diagnosis of Chagas disease are commonly sent to our School of Veterinary Medicine by independent veterinarians. This prompted us to evaluate the prevalence of canine trypanosomiasis in some villages of the Central Valley of Costa Rica. A total of 54 dogs (21 males and 33 females) from five rural villages, with ages between 3 months and 10 years old, were bled and submitted to three serological tests: indirect immunofluorescence, indirect hemagglutination and ELISA. Among all animals, 15 (27.7%) revealed antibodies (6 pure bred and 9 mongrels) and in 3 of them the parasite was also demonstrated by xenodiagnosis. All positive animals except 1, and 9 negative animals (control group) were examined by X-rays and electrocardiography, revealing different degrees of cardiomegaly and ECG alteration, consistent with Chagas disease pathology in one dog (SA-11) of the infected ones. Examination of 50 inhabitants living in the houses where dogs and Triatoma dimidiata were found, yielded negative serological reactions. This was assumed to support the hypothesis that dogs are commonly infected by the oral route, a more effective means of infection compared with the vector transmission mechanism that occurs in humans.
  • Redescrição de Litomosoides brasiliensis Almeida, 1936 (Nematoda: Filariidae) Parasito de Anoura caudifera (Chiroptera: Phyllostomidae)

    Mourão, Elizabeth D; Avilla, Leonardo dos S; Lent, Herman

    Resumo em Inglês:

    The study of the surface topography added details regarding the disposition of male caudal papillae, spicules and area rugosa apart from vulva and oral aperture. The occurrence of this nematode in the state of Amapá represents a new geographical distribution.
  • Description of Pintomyia (Pifanomyia) falcaorum sp. n. (Diptera: Psychodidae: Phlebotominae), a Fossil Sand Fly from Dominican Amber Systematics

    Brazil, Reginaldo Peçanha; Andrade Filho, José Dilermando

    Resumo em Inglês:

    A new species of sand fly, Pintomyia (Pifanomyia) falcaorum is described from an amber originated from the northern mountain range of Dominican Republic. The male sand fly specimen is well preserved and most features used in Phlebotominae taxonomy are seen with remarkable clarity.
  • Plesiophysa dolichomastix sp. n. (Gastropoda: Planorbidae) Systematics

    Paraense, W Lobato

    Resumo em Inglês:

    A new species of planorbid mollusc, Plesiophysa dolichomastix (Greek dolichos = long, mastix = flagellum), collected from Lagoa da Pedra, municipality of Santa Rosa, state of Goiás, Brazil (15°01'S, 47°13'W) is described. It is indistinguishable by the shell characters from the five congeneric species described so far: P. striata (Orbigny, 1841), P. granulata ("Shuttleworth" Sowerby, 1873), P. guadeloupensis ("Fischer" Mazé, 1883), P. ornata (Haas, 1938) and P. hubendicki Richards & Ferguson, 1962. It differs from the anatomically studied species in the following characters: about 50 ovotestis diverticula, against 12 in granulata, 100 in ornata, unstated in hubendicki; and length of flagella - about as long as the penial complex -, against about 1/3 to 1/6 in the other three.
  • Capillariidae Eggs Found in the Urine of a Free Ranging Maned Wolf from Argentina Systematics

    Martín Beldomenico, Pablo; Hunzicker, Daniel; Lopez Taverna, Julio; Rejf, Paula K

    Resumo em Inglês:

    The first finding of a Capillariid in the urinary tract of a free ranging maned wolf (Chrysocyon brachyurus) is described. The individual was an adult male attacked by dogs in the locality of Cayastacito (Santa Fe, Argentina, 31º05' S, 60º 34' W). Eggs found in urine measured 64.6-66.9µm (mean 65.4µm) x 26.9-31µm (mean 29µm). Further studies are needed to determine whether this finding corresponds to a new Capillariid species, related to C. brachyurus, or it is an already described species that has been introduced by domestic dogs.
  • The Zymovars of Vibrio cholerae: Multilocus Enzyme Electrophoresis of Vibrio cholerae Immunogenetic

    Freitas, Fernanda S; Momen, Hooman; Salles, Carlos Andre

    Resumo em Inglês:

    Zymovars analysis also known as multilocus enzyme electrophoresis is applied here to investigate the genetic variation of Vibrio cholerae strains and characterise strains or group of strains of medical and epidemiological interest. Fourteen loci were analyzed in 171 strains of non-O1 non-O139, 32 classical and 61 El Tor from America, Africa, Europe and Asia. The mean genetic diversity was 0.339. It is shown that the same O antigen (both O1 and non-O1) may be present in several geneticaly diverse (different zymovars) strains. Conversely the same zymovar may contain more than one serogroup. It is confirmed that the South American epidemic strain differs from the 7th pandemic El Tor strain in locus LAP (leucyl leucyl aminopeptidase). Here it is shown that this rare allele is present in 1 V. mimicus and 4 non-O1 V. cholerae. Non toxigenic O1 strains from South India epidemic share zymovar 14A with the epidemic El Tor from the 7th pandemic, while another group have diverse zymovars. The sucrose negative epidemic strains isolated in French Guiana and Brazil have the same zymovar of the current American epidemic V. cholerae.
  • Anionic Sites, Fucose Residues and Class I Human Leukocyte Antigen Fate During Interaction of Toxoplasma gondii with Endothelial Cells Immunogenetic

    Stumbo, Ana Carolina; Barbosa, Helene Santos; Carvalho, Técia Maria Ulisses de; Porto, Luís Cristóvão; Carvalho, Laís de

    Resumo em Inglês:

    Toxoplasma gondii invades and proliferates in human umbilical vein endothelial cells where it resides in a parasitophorous vacuole. In order to analyze which components of the endothelial cell plasma membrane are internalized and become part of the parasitophorous vacuole membrane, the culture of endothelial cells was labeled with cationized ferritin or UEA I lectin or anti Class I human leukocytte antigen (HLA) before or after infection with T. gondii. The results showed no cationized ferritin and UEA I lectin in any parasitophorous vacuole membrane, however, the Class I HLA molecule labeling was observed in some endocytic vacuoles containing parasite until 1 h of interaction with T. gondii. After 24 h parasite-host cell interaction, the labeling was absent on the vacuolar membrane, but presents only in small vesicles near parasitophorous vacuole. These results suggest the anionic site and fucose residues are excluded at the time of parasitophorous vacuole formation while Class I HLA molecules are present only on a minority of Toxoplasma-containig vacuoles.
  • Polymorphism of the Human Immunodeficiency Virus Type 1 in Brazil: Genetic Characterization of the nef Gene and Implications for Vaccine Design Immunogenetic

    Guimarães, ML; Moreira, AS; Morgado, MG

    Resumo em Inglês:

    Most of the Brazilian HIV-1 samples have been characterized based on the structural genes (env, gag and pol) and no data concerning the variability of the accessory genes such as nef have been available so far. Considering the role of the nef on virus biology and the inclusion of this region in some HIV/AIDS vaccine products under testing, the purpose of this study was to document the genetic diversity of the nef gene in third-four HIV-1 Brazilian samples previously subtyped based on the env C2-V3 region. Although only few non-subtype B samples have already been analyzed so far, the cytotoxic Tlymphocyte epitopes encoded in this region were relatively conserved among the subtypes, with some amino acid signatures mainly in the subtype C samples. Considering the increasing of the non-B HIV-1 subtypes worldwide, in special the subtype C, more data should be generated concerning the genetic and antigenic variability of these subtypes, as well as the study of the impact of such polymorphism in HIV/AIDS vaccine design and testing.
  • Microsporidiosis of Tachinaephagus zealandicus Ashmead (Hymenoptera: Encyrtidae) Control

    Almeida, Maria A Ferreira de; Geden, Christopher J; Boohene, Carl K; Becnel, James J; Prado, Angelo Pires do

    Resumo em Inglês:

    An undescribed microsporidium was found infecting Tachinaephagus zealandicus, a gregarious parasitoid that attacks third instar larvae of muscoid flies. Spores were present in all body regions and in all stages of development. Infected adults contained an average of 3.75 x 10(5) spores, and the pathogen was vertically transmitted to progeny. Infected female adults were fed either rifampicin or albendazole mixed with honey to determine the effectiveness of these drugs in preventing vertical transmission. After eight days of feeding on rifampicin the parasitoids produced progeny of which only 37% were infected. In contrast, albendazole-treated and untreated females produced progeny that were 97% and 100% infected, respectively. Healthy and infected colonies were established and studies were conducted to determine the mechanisms of transmission. It was observed that the efficiency of vertical (maternal) transmission was 96.3%. Uninfected parasitoid immatures also became infected when they shared superparasitized hosts with infected immatures. The method of transmission within superparasitized hosts is not known.
  • Predation Potential of the Water Bugs Sphaerodema rusticum on the Sewage Snails Physa acuta Control

    Aditya, G; Raut, SK

    Resumo em Inglês:

    The sewage snail Physa acuta is a serious threat to certain economic plants and to the purification plant of sewage works by rendering the biofilters ineffective. Various attempts are being made to control it. The efficacy of the predacious water bugs Sphaerodema rusticum was judged experimentally, in the laboratory in the potential control of P. acuta. It is revealed that, when supplied separately, the first, second and third instar and the adult S. rusticum did not attack P. acuta belonging to 3.1-8 mm, 5.1-8 mm, 7.1-8 mm and <= 3 mm size classes respectively. In the remaining trials predation rate varied from zero to eight (average 2.3) individuals per predator per day. In experiments with P. acuta belonging to all the size classes supplied together, none, except the first instar S. rusticum, attacked the prey individuals belonging to the lowest (<= 3 mm) size class. The first and second instar S. rusticum, in both trials did not attack P. acuta larger than 4 mm and 5 mm in shell length respectively. The water bugs belonging to the third, fourth, fifth instar and adult stages though preyed upon P. acuta with 3.1-8 mm shell length. The average rate of predation by a single S. rusticum varied from 0.14-3.08 individuals per day depending upon the size of P. acuta and the stage of S. rusticum. A single S. rusticum, irrespective of instar and adult stages, destroyed on average 4.16 P. acuta daily irrespective of sizes. It is estimated that one S. rusticum could destroy 1,360 P. acuta in its life time. The results clearly indicate that the water bug S. rusticum may be used to control the snails P. acuta.
  • Fipronil Insecticide: Novel Application against Triatomine Insect Vectors of Chagas Disease Control

    Rojas de Arias, Antonieta; Fournet, Alain

    Resumo em Inglês:

    We investigated the efficacy and the residual effect of fipronil® against two species of triatomine bugs, Triatoma infestans and Rhodnius neglectus, in laboratory conditions measuring concentration-response and residual activity on different surfaces (dried mud and lime coated mud). Lethal concentrations (LC50,90) were determined on filter paper. The higher insecticide efficacy against R. neglectus when compared to T. infestans may be partially attributed to the differences in their biological cycles and genetic structures. Comparison with lambdacyhalothrin wettable powder showed that fipronil mortality rates (above 50%) were observed on mud blocks and lime-coated mud blocks up to 3 months when fipronil was sprayed at 100 and 200 mg a.i./m². Residual effect deeply decayed after 3 months; and at 6 months post treatment mortality was not observed. In contrast, lambdacyhalothrin showed a long lasting residual effect on both surfaces up to 6 months. Also, it should be mentioned that fipronil had a slow, but lethal activity on the triatomine bugs when wettable formulations were used on porous surfaces.
  • Cytotoxic and Antiviral Activities of Colombian Medicinal Plant Extracts of the Euphorbia genus Experimental Therapy

    Betancur-Galvis, LA; Morales, GE; Forero, JE; Roldan, J

    Resumo em Inglês:

    Forty-seven plant extracts of 10 species of the genus Euphorbia (Euphorbiaceae) used by Colombian traditional healers for the treatment of ulcers, cancers, tumors, warts, and other diseases, were tested in vitro for their potential antitumour (antiproliferative and cytotoxic) and antiherpetic activity. To evaluate the capacity of the extracts to inhibit the lytic activity of herpes simplex virus type 2 (HSV-2) and the reduction of viability of infected or uninfected cell cultures, the end-point titration technique (EPTT) and the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] colorimetric assay were used, respectively. The therapeutic index of the positive extracts for the antiviral activity was determined by calculating the ratio CC50 (50% cytotoxic concentration) over IC50 (50% inhibitory concentration of the viral effect). Five of the 47 extracts (11%) representing 3 out of 10 Euphorbia species (30%) exhibited antiherpetic action; the highest activity was found in the leaf/stem water-methanol extracts from E. cotinifolia and E. tirucalli. The therapeutic indexes of these two plant species were > 7.1; these extracts exhibited no cytotoxicity. Six extracts (13%) representing 4 plant species (40%) showed cytotoxic activity. The highest cytotoxicity was found in the dichloromethane extract obtained from E. cotinifolia leaves and the CC50 values for the most susceptible cell lines, HEp-2 and CHO, were 35.1 and 18.1 µg/ml, respectively.
  • An Adenovirus Vector Containing the Suicide Gene Thymidine Kinase for a Broad Application in Cancer Gene Therapy Experimental Therapy

    Magalhães, GS; Muotri, AR; Marchetto, MCN; Menck, CFM; Ventura, AM

    Resumo em Inglês:

    Treatment of cancer using gene therapy is based on adding a property to the cell leading to its elimination. One possibility is the use of suicide genes that code for enzymes that transform a pro-drug into a cytotoxic product. The most extensively used is the herpes simplex virus thymidine kinase (TK) gene, followed by administration of the antiviral drug ganciclovir (GCV). The choice of the promoter to drive the transcription of a transgene is one of the determinants of a given transfer vector usefulness, as different promoters show different efficiencies depending on the target cell type. In the experiments presented here, we report the construction of a recombinant adenovirus carrying TK gene (Ad-TK) driven by three strong promoters (P CMV IE, SV40 and EN1) and its effectiveness in two cell types. Human HeLa and mouse CCR2 tumor cells were transduced with Ad-TK and efficiently killed after addition of GCV. We could detect two sizes of transcripts of TK gene, one derived from the close together P CMV IE/SV40 promoters and the other from the 1.5 Kb downstream EN1 promoter. The relative amounts of these transcripts were different in each cell type thus indicating a higher flexibility of this system.
  • In Vitro and in Vivo Anti-Trypanosoma cruzi Activity of a Novel Nitro-derivative Experimental Therapy

    Muelas-Serrano, Susana; Le-Senne, Ana; Fernández-Portillo, Carlos; Nogal, Juan José; Ochoa, Carmen; Gómez-Barrio, Alicia

    Resumo em Inglês:

    Nitroarylidenemalononitriles and their cyanoacetamide derivatives with remarkable anti-epimastigote properties, were synthesized attempting to obtain new 3,5-diamino-4-(5'-nitroarylidene)-4H-thiadiazine 1,1-dioxide derivatives, which in previous reports had shown anti-Trypanosoma cruzi activity. Tests to evaluate the cytotoxicity of compounds were performed on J774 macrophages. 5-nitro-2-thienyl-malononitrile (5NO2TM), was the only product which maintained a high anti-epimastigote activity at concentrations in which it was no longer cytotoxic, thus it was assayed against intracellular amastigotes. Its anti-amastigote activity was similar to that of nifurtimox. Afterwards in vivo toxicity and anti-chagasic activity were determined. A reduction in parasitemia was observed.
  • Assessment of Therapeutic Response of Plasmodium vivax and Plasmodium falciparum to Chloroquine in a Malaria Transmission Free Area in Colombia Clinical Therapeutic Studies

    Castillo, Carmen Manuela; Osorio, Lyda Elena; Palma, Gloria Inés

    Resumo em Inglês:

    In order to determine the frequency of therapeutic failures to chloroquine (CQ) in patients with malaria due to either Plasmodium falciparum or P. vivax, and to explore the usefulness of a malaria-free city as a sentinel site to monitor the emergence of drug resistance, 53 patients (44 infected with P. vivax and 9 with P. falciparum) were evaluated at the Laboratory of Parasitology, Universidad del Valle in Cali, Colombia. Patients received 25 mg/kg of CQ divided in three doses over 48 h; they were followed during 28 days according to WHO/PAHO protocols. While therapeutic failures to CQ in the P. vivax group were not detected, the proportion of therapeutic failures in the P. falciparum group was high (78%) and consistent with the reports from endemic areas in Colombia. The diverse origin of cases presenting therapeutic failure confirmed that P. falciparum resistant to CQ is widespread in Colombia, and further supports the change in the national antimalarial drug scheme. Monitoring of drug resistance in malaria free areas would be useful to identify sites requiring efficacy evaluation, and in some situations could be the most appropriate alternative to collect information from endemic areas where therapeutic efficacy studies are not feasible.
  • Lack of Correlation between Seminal and Plasma HIV-1 Viral Loads is Associated with CD4T Cell Depletion in Therapy-naïve HIV-1+ Patients Clinical Therapeutic Studies

    Pinto-Neto, Lauro FS; Vieira, Nilo FR; Soprani, Moacir; Cunha, Carla B; Dietze, Reynaldo; Ribeiro-Rodrigues, Rodrigo

    Resumo em Inglês:

    The present study was conducted to investigate a possible correlation between plasma (PVL) and seminal viral load (SVL) on treatment-naïve HIV-1-infected patients in Vitória, ES, Brazil. We also evaluated whether the progressive immunosuppression associated with HIV disease (as evidenced by declining CD4 T cell counts) has any impact on the correlation between PVL and SVL HIV-1. Viral load on paired blood and semen samples from 56 consecutive treatment-naïve patients were evaluated and compared to CD4 cell counts. Viral load and T cell counts (cells/µl) were determined by NASBA and by flow cytometry, respectively. Overall, a strong positive correlation between PVL and SVL (rho = 0.438, p = 0.001) was observed. However, when patients were grouped according to their CD4 counts, this correlation was only significant among patients with CD4 counts > 200 cells/µl. Results presented here demonstrate the existence of a strong correlation between PVL and SVL on patients with CD4 cell counts > 200 cells/µl, suggesting that this association may correlate with disease progression.
  • Aggregation Behaviour and Interspecific Responses in Rhodnius prolixus Stål General Biology

    Figueiras, Alicia N Lorenzo; Lazzari, Claudio R

    Resumo em Inglês:

    The response to intra- and interspecific faecal assembling signals was tested in Rhodnius prolixus. Papers impregnated with excrement of R. prolixus induced the aggregation of larvae of this species, but also of those of Triatoma infestans. However, faeces belonging to T. infestans were not able to assemble larvae of R. prolixus. On the other hand, there was no response of R. prolixus to putative chemical factors from their cuticle (footprints), in contrast to T. infestans. Results are discussed as related to the ecology of both species.
  • Experimental Infection of Aedes albopictus (Diptera: Culicidae) Larvae with the Xiphidiocercariae of a Hematolechid General Biology

    Carvalho, Gílcia Aparecida de; Andrade, Carlos Fernando S; Ueta, Marlene Tiduko

    Resumo em Inglês:

    Aedes albopictus larvae were exposed, either individually or in groups, to different concentrations of xiphidiocercariae of Haematoloechus sp. for parasitological studies. It was observed the acute lethal effect and some aspects of the host-parasite relationship, such as delay or progress in the host life cycle, the number and location of the metacercariae in the host, adult host malformations and the amount of metacercariae required to cause death. A delay in the cycle and a high mortality rate was in general observed. Inside the larvae, the metacercariae were found predominantly in the thorax, abdominal segments and in the head, along with a reduced number in the anal lobe and cervix. It was shown that in addition to the quantity of metacercariae present, their location in the larvae was also relevant in the determination of mortality and anomalies. Malformed adults developed from larvae containing from one to three metacercariae.
  • Effect of Sequential Cold Shocks on Survival and Molting Rate in Triatoma infestans Klug General Biology

    Campos, Silvana GP; Rodrigues, Vera Lúcia CC; Wada, CY; Mello, Maria Luiza S

    Resumo em Inglês:

    The survival and molting incidence in Triatoma infestans, a vector of Chagas disease, were investigated following sequential shocks at 0ºC in fifth instar nymphs under moderate fasting and full nutritional conditions. The shocks were separated by intervals of 8 h and 24 h at 30ºC. The results indicated that in terms of insect survival, T. infestans is tolerant to a single cold shock at 0ºC even for 12 h, or to sequential cold shocks, regardless of the nutritional state of the specimens. In terms of molting rate, fasting enhanced the tolerance to sequential cold shocks, but did not exceed the tolerance acquired by fully-nourished specimens, except when cold shocks were separated by an 8 h interval at 30ºC. The protective action elicited by fasting was assumed to be additive to that induced by a single mild cold shock or sequential cold shocks. The cold-tolerance response of T. infestans may have favoured its survival in areas of South America with low temperatures, even considering that this species is predominantly associated with human habitats.
  • Biology of Triatoma klugi Carcavallo, Jurberg, Lent & Galvão 2001 (Heteroptera: Reduviidae) under Laboratory Conditions: Effects of Distinct Blood Sources and Susceptibility to Trypanosoma cruzi and Trypanosoma rangeli General Biology

    Emmanuelle-Machado, Priscilla; Koerich, Leonardo B; Joukoski, Daiene De Boni; Carvalho-Pinto, Carlos J; Grisard, Edmundo C; Steindel, Mário

    Resumo em Inglês:

    The life cycle of Triatoma klugi Carcavallo, Jurberg, Lent & Galvão 2001 was compared under laboratory conditions using two groups of the F1 generation obtained from field-collected bugs. Among the 100 nymphs weekly fed on mice (Group A) or chicken (Group B), 77% of Group A and 67% of Group B reached the adult stage, and the mean time from the first nymphal stage to adult was 190.08 ± 28.31 days and 221.23 ± 40.50, respectively. The average span in days for each stage per group and the number of blood meals required for each stage were also evaluated. The overall mortality rate was 23% and 33% for Groups A and B, respectively. The mean number of eggs laid per month in a three-month period was of 56.20, 51.70 and 73.20 for Group A, and 64.50, 53.50 and 38.71 for Group B. Despite the blood source, comparative analysis revealed no statistically significant differences in the life cycle of T. klugi under laboratory conditions. Infection rates over 60% were observed for both Trypanosoma cruzi strains tested. Even revealing high infection rates of the hemolymph by T. rangeli strains, T. klugi revealed no salivary gland infections and was not able to transmit the parasite.
  • Anopheles albitarsis Embryogenesis: Morphological Identification of Major Events General Biology

    Monnerat, Adelaide Tardin; Machado, Marcelo Pelajo; Vale, Bruno Silva; Soares, Maurilio José; Lima, José Bento Pereira; Lenzi, Henrique Leonel; Valle, Denise

    Resumo em Inglês:

    Anopheles albitarsis embryogenesis was analyzed through confocal microscopy of clarified eggs. Using Drosophila melanogaster as reference system, the major morphogenetic events (blastoderm, gastrulation, germ band extension, germ band retraction, dorsal closure) were identified. The kinetics of early events is proportionally similar in both systems, but late movements (from germ band retraction on) progress slower in An. albitarsis. Major differences in An. albitarsis related to D. melanogaster were: (1) pole cells do not protrude from the blastoderm; (2) the mosquito embryo undergoes a 180º rotation movement, along its longitudinal axis; (3) the head remains individualized throughout embryogenesis; (4) extraembryonary membranes surround the whole embryo. A novel kind of malaria control is under development and is based on the use of genetically modified mosquitoes. Phenotypic analysis of the embryonic development of mutants will be imposed as part of the evaluation of effectiveness and risk of employment of this strategy in the field. In order to accomplish this, knowledge of the wild type embryo is a prerequisite. Morphological studies will also serve as basis for subsequent development biology approaches.
  • Pelecitus helicinus Railliet & Henry, 1910 (Filarioidea, Dirofilariinae) and Other Nematode Parasites of Brazilian Birds General Biology

    Oniki, Yoshika; Kinsella, JM; Willis, Edwin O

    Resumo em Inglês:

    We report Pelecitus helicinus Railliet & Henry, 1910 from 13 species of birds of 2 orders and 7 families, collected from the states of São Paulo and Mato Grosso, Brazil. All 13 constitute new host records for this nematode. In addition, we report the first record of Aprocta golvani Diaz-Ungria, 1963 from Brazil and Monasa nigrifrons (Bucconidae), as well as a number of other nematode records from Neotropical birds.
  • Experimental Neuroschistosomiasis: Inadequacy of the Murine Model General Biology

    Silva, Luciana M; Oliveira, Carla Neves de; Andrade, Zilton A

    Resumo em Inglês:

    Neuroschistosomiasis is rarely observed in human pathology, but it is of considerable importance. To investigate its pathogenesis, consequences and response to treatment, an experimental model would be desirable, but is not yet available, in spite of a few indications of a suitable mouse model in the literature. Severe, recent and late Schistosoma mansoni infections in outbred and inbred strains of mice revealed widespread distribution of parasite eggs in several organs, but only exceptionally did eggs reach the encephalus, thus revealing the inadequacy of the mouse as an experimental model for neuroschistosomiasis.
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