RESUMO
A experimentação animal é primordial para os avanços científicos em prol da saúde humana e animal. Inúmeros parasitos que acometem animais de laboratório podem interferir nas pesquisas, comprometendo os resultados. O protozoário Tritrichomonas muris pode ser um bioindicador de quebra de barreiras sanitárias em instalações de animais de laboratório, auxiliando na conduta do manejo e melhoria do padrão de qualidade animal. Este trabalho comparou três métodos parasitológicos, visando implantar a metodologia mais adequada em uma rotina de monitoramento sanitário de um biotério de criação de hamsters golden (Mesocricetus auratus). Foram utilizados 50 hamsters, entre três meses a um ano de idade, selecionados por amostragem, para exames parasitológicos nos períodos de monitoramento sanitário pré-estabelecidos. A análise foi feita por dois anos, abrangendo um total de oito exames trimestrais. O diagnóstico foi realizado por exame direto, flutuação de Willis-Mollay e sedimentação espontânea de Dennis Stone & Swanson a partir da mucosa intestinal e das fezes frescas in natura. Foram identificados apenas trofozoítos de T. muris nas três primeiras porções intestinais selecionadas no estudo (intestino delgado, ceco e cólon), enquantoa forma de pseudocisto foi detectada nas amostras fecais e na região do reto onde já há fezes formadas. Tais achados são embasados no mecanismo do ciclo de vida do protozoário em questão. O método direto mostrou maior eficácia para o diagnóstico de T. muris para a identificação de trofozoítos e pseudocistos, tanto nas fezes formadas, como na mucosa intestinal devidamente fragmentada em suas diferentes regiões.(AU)
Animal experimentation is primordial to scientific advances for human and animal health. Numerous parasites that affect laboratory animals can interfere with research, compromising the results. The protozoan Tritrichomonas muris can be a bioindicator of breaking down health barriers in laboratory animal facilities, helping to conduct management and improve animal quality standards. This work compared three parasitological methods, aiming to implement the most suitable methodology in a sanitary monitoring routine of a golden hamster breeding (Mesocricetus auratus). Fifty hamsters from three months to one year of age, selected by sampling, were used for parasitological examinations in pre-established sanitary monitoring periods. Analysis was performed for two years, covering a total of eight quarterly exams. The diagnosis was carried out by direct examination, Willis-Mollay flotation and spontaneous sedimentation by Dennis Stone & Swanson from the intestinal mucosa and fresh stool. Only T. muris trophozoites were identified in the first three intestinal portions selected in the study (small intestine, cecum and colon), while the pseudocyst form was detected in faecal samples and in the rectal region where there are already formed stools. Such findings are based on the life-cycle mechanism of this protozoan. The direct method showed greater efficacy for the diagnosis of T. muris for the identification of trophozoites and pseudocysts, both in formed feces and in the intestinal mucosa, properly fragmented in their different regions.(AU)
Assuntos
Animais , Cricetinae , Tritrichomonas/isolamento & purificação , Tritrichomonas/patogenicidade , Infecções por Protozoários/diagnóstico , Mesocricetus/parasitologia , Animais de LaboratórioRESUMO
A experimentação animal é primordial para os avanços científicos em prol da saúde humana e animal. Inúmeros parasitos que acometem animais de laboratório podem interferir nas pesquisas, comprometendo os resultados. O protozoário Tritrichomonas muris pode ser um bioindicador de quebra de barreiras sanitárias em instalações de animais de laboratório, auxiliando na conduta do manejo e melhoria do padrão de qualidade animal. Este trabalho comparou três métodos parasitológicos, visando implantar a metodologia mais adequada em uma rotina de monitoramento sanitário de um biotério de criação de hamsters golden (Mesocricetus auratus). Foram utilizados 50 hamsters, entre três meses a um ano de idade, selecionados por amostragem, para exames parasitológicos nos períodos de monitoramento sanitário pré-estabelecidos. A análise foi feita por dois anos, abrangendo um total de oito exames trimestrais. O diagnóstico foi realizado por exame direto, flutuação de Willis-Mollay e sedimentação espontânea de Dennis Stone & Swanson a partir da mucosa intestinal e das fezes frescas in natura. Foram identificados apenas trofozoítos de T. muris nas três primeiras porções intestinais selecionadas no estudo (intestino delgado, ceco e cólon), enquantoa forma de pseudocisto foi detectada nas amostras fecais e na região do reto onde já há fezes formadas. Tais achados são embasados no mecanismo do ciclo de vida do protozoário em questão. O método direto mostrou maior eficácia para o diagnóstico de T. muris para a identificação de trofozoítos e pseudocistos, tanto nas fezes formadas, como na mucosa intestinal devidamente fragmentada em suas diferentes regiões.
Animal experimentation is primordial to scientific advances for human and animal health. Numerous parasites that affect laboratory animals can interfere with research, compromising the results. The protozoan Tritrichomonas muris can be a bioindicator of breaking down health barriers in laboratory animal facilities, helping to conduct management and improve animal quality standards. This work compared three parasitological methods, aiming to implement the most suitable methodology in a sanitary monitoring routine of a golden hamster breeding (Mesocricetus auratus). Fifty hamsters from three months to one year of age, selected by sampling, were used for parasitological examinations in pre-established sanitary monitoring periods. Analysis was performed for two years, covering a total of eight quarterly exams. The diagnosis was carried out by direct examination, Willis-Mollay flotation and spontaneous sedimentation by Dennis Stone & Swanson from the intestinal mucosa and fresh stool. Only T. muris trophozoites were identified in the first three intestinal portions selected in the study (small intestine, cecum and colon), while the pseudocyst form was detected in faecal samples and in the rectal region where there are already formed stools. Such findings are based on the life-cycle mechanism of this protozoan. The direct method showed greater efficacy for the diagnosis of T. muris for the identification of trophozoites and pseudocysts, both in formed feces and in the intestinal mucosa, properly fragmented in their different regions.
Assuntos
Animais , Cricetinae , Cricetinae , Cricetinae , Infecções por Protozoários/diagnóstico , Tritrichomonas/isolamento & purificação , Tritrichomonas/patogenicidade , Animais de Laboratório , Mesocricetus/parasitologiaRESUMO
A variety of clinical forms of American cutaneous leishmaniasis (ACL) caused by Leishmania braziliensis, as well as differing immune responses of patients, have been reported for an ACL focus in the state of Minas Gerais, Brazil. In addition, two genetic profiles of L. braziliensis have been described, of which one variant profile (hsp70-variant) has been associated with atypical lesions. We investigated the biological behavior of genetic variant strains of L. braziliensis isolated from patients with different clinical manifestations of ACL. Experimental infections were performed with golden hamsters for five L. braziliensis strains in standardized doses of 1 × 106 parasites per inocula. The characteristics of skin lesions, histopathological features, and parasite burden were independently analyzed at 30 and 60 days post-infection. The data revealed distinct patterns in the onset time of visible skin lesions as well as in lesion size and parasite burden among the strains. The extent and density of the inflammatory infiltrate differed among strains, although cellular composition of granulomas appeared similar. Multivariate analysis indicated the occurrence of two clusters: one comprising native strains (cluster 1) and one comprising the reference strain (cluster 2). Within cluster 1, the genetic variants of L. braziliensis did not group with the non-variant strain suggesting that the distinct patterns of biological behavior of these strains could be associated with the known genetic diversity previously described for them.
Assuntos
Variação Genética/genética , Leishmania braziliensis/genética , Leishmaniose Cutânea/patologia , Pele/patologia , Adulto , Animais , Brasil/epidemiologia , Cricetinae , Proteínas de Choque Térmico HSP70/genética , Humanos , Leishmania braziliensis/classificação , Leishmania braziliensis/isolamento & purificação , Leishmaniose Cutânea/epidemiologia , Leishmaniose Cutânea/parasitologia , Masculino , Mesocricetus/parasitologia , Pele/parasitologiaRESUMO
In this survey, intestinal helminths from pet rodents in Mérida, México, were analyzed. A total of 46 mice Mus musculus, 28 hamsters Mesocricetus auratus, 23 rats Rattus norvegicus, and 1 gerbil Meriones unguiculatus were purchased from six pet shops and one black market for wildlife in the city of Mérida. The overall prevalence of helminths in rodents was 61.2% (60/98). Six species of helminths were identified: the zoonotic cestode Rodentolepis nana, and the nematodes Aspiculuris tetraptera, Dentostomella translucida, Syphacia obvelata, Syphacia mesocriceti, and Syphacia muris. Of the 60 infected rodents, 25 (41.7%) harbored 2 or 3 species of helminths. Rodentolepis nana was found in 4.3% of mice and 17.9% of hamsters. This is the first report of infection with S. muris in pet rats. Considering the close physical contact between pet rodents and humans, the presence of R. nana in pets represents a potential risk of transmission, especially to children and immunocompromised individuals.
Assuntos
Cestoides/isolamento & purificação , Nematoides/isolamento & purificação , Oxyuroidea/isolamento & purificação , Animais de Estimação/parasitologia , Doenças dos Roedores/parasitologia , Animais , Infecções por Cestoides/epidemiologia , Infecções por Cestoides/parasitologia , Infecções por Cestoides/veterinária , Cricetinae , Feminino , Gerbillinae/parasitologia , Intestinos/parasitologia , Mesocricetus/parasitologia , México/epidemiologia , Camundongos , Infecções por Nematoides/epidemiologia , Infecções por Nematoides/parasitologia , Infecções por Nematoides/veterinária , Oxiuríase/epidemiologia , Oxiuríase/parasitologia , Oxiuríase/veterinária , Prevalência , Ratos , Inquéritos e QuestionáriosRESUMO
The parasite Entamoeba histolytica causes intestinal amebiasis and amebic liver abscess as its main extraintestinal manifestation. To study the in vivo events related to inflammation and the interactions between hosts and parasites during amebiasis, we designed a novel model of host-parasite interactions using cellulose membrane dialysis bags containing E. histolytica trophozoites. A bag is placed into the hamster peritoneal cavity, as has been reported in previous studies of programmed cell death (PCD) in E. histolytica trophozoites. To determine if virulence factors such as cysteine proteinases (EhCP2 and EhCP5) and Gal/GalNAc lectin could be involved in the host-parasite interaction using this model, we examined the relative expression of the ehcp2 and ehcp5 genes and the carbohydrate recognition domain (crd) of Gal/GalNAc lectin using real-time quantitative PCR (qRT-PCR). All analyzed genes were over-expressed 0.5h after the initiation of the host-parasite interaction and were then progressively down-regulated. However, Gal/GalNAc lectin had the greatest increase in gene expression 1.5h after host-parasite interaction; Gal/GalNAc lectin had a 250-fold increase with respect to the axenically grown trophozoites, which over-express Gal/GalNAc lectin in in vivo models. These results support the important role of these molecules in the initiation of cell damage by E. histolytica.
Assuntos
Acetilgalactosamina/metabolismo , Cisteína Endopeptidases/metabolismo , Entamoeba histolytica/metabolismo , Entamebíase/parasitologia , Mesocricetus/parasitologia , Animais , Cricetinae , Cisteína Endopeptidases/genética , Disenteria Amebiana/parasitologia , Entamoeba histolytica/genética , Interações Hospedeiro-Parasita , Humanos , Lectinas/metabolismo , Abscesso Hepático Amebiano/parasitologia , Masculino , Proteínas de Protozoários/genética , Trofozoítos/patologiaRESUMO
This study was performed to gain insight into the maturation of the reproductive system of Echinostoma paraensei worms grown in an early infection of Mesocricetus auratus. Hamsters were infected with 100 metacercariae and necropsied on days 3, 5, 7, 10 and 14 post infection (dpi). Recovered flukes stained with hydrochloric carmine were preserved as whole mounts and analyzed by light and confocal scanning laser microscopy. The average worm recovery was 43.7 per host. Images of the male and female reproductive systems were taken. The ovary and anterior and posterior testis were evidenced on day 3, while the ootype and cirrus sac were present on day 5. Confocal imaging showed primordium testis and ovary as a cluster of primordial cells from day 3 onward. The testes, ovary, cirrus sac and uterus organs were already present during the first week of life. The two testes were seen as individual structures on 7 dpi while the cirrus sac and vitelline glands were in development. The ovary was connected to the uterus while the ootype was adjacent to it. Both testes were larger than the ovary, showing cells at different stages of development, but with few bundles of functional spermatozoa in 10 day-old worms. On day 14, eggs and spermatozoa were seen in the uterus and seminal vesicle, respectively, while oocytes appeared in the ootype as fertilized eggs. We conclude that the reproductive system of E. paraensei was functional on 14 dpi in the hamsters.
Assuntos
Modelos Animais de Doenças , Echinostoma/crescimento & desenvolvimento , Equinostomíase/parasitologia , Mesocricetus/parasitologia , Animais , Biomphalaria , Cricetinae , Feminino , Genitália/citologia , Genitália/crescimento & desenvolvimento , Interações Hospedeiro-Parasita , Masculino , Microscopia ConfocalRESUMO
Visceral leishmaniasis (VL) is a severe chronic disease caused by Leishmania (Leishmania) infantum chagasi. Better knowledge on the effects caused by this disease can help develop adequate clinical management and treatment. Parasitological and immunohistochemical studies were performed golden hamsters Mesocricetus auratus infected with bone marrow from individuals with VL in the State of Mato Grosso do Sul, central-west Brazil. The effects of parasitism in the spleen, liver, kidneys, lungs, heart and brain of the animals were examined. Eighteen hamsters were inoculated intraperitoneally, and six healthy animals were used as negative controls. The animals were kept in the animal house and checked for clinical signs. Specimens of each organ were examined for the presence of amastigotes. Immunohistochemical technique was performed in all brain specimens and organs negative on the direct examination of parasites. Direct examination of amastigotes was positive in the spleen and liver of all infected animals; 33.3% showed the parasite in the kidneys and lungs, and 16.7% in the heart. Parasitic forms were seen in 83.3% (15/18) of the brain examined. Immunohistochemistry confirmed the results of the direct examination, except in two specimens of lung tissue and in the brain specimens. Other studies are needed to further clarify the effect of the parasite in the central nervous system.(AU)
A leishmaniose visceral (LV) é uma doença crônica grave, causada pelo parasito Leishmania (Leishmania) infantum chagasi. Esclarecer as alterações provocadas pela doença é fundamental para que se adotem condutas clínicas e de tratamento adequadas. Com o objetivo de analisar a infecção experimental em hamsters da linhagem golden, Mesocricetus auratus, infectados com tecido de medula óssea de pacientes com LV no Estado de Mato Grosso do Sul, foram realizados estudos parasitológicos e de imunomarcação. Foi verificada a distribuição do parasitismo no baço, fígado, rim, pulmão, coração e encéfalo desses animais. Foram utilizados 18 hamsters experimentalmente inoculados via intra-peritoneal, e seis animais sadios como controles negativos. Os animais foram mantidos em biotério de experimentação e observados, em busca de alterações clínicas. Com fragmentos de cada órgão, procedeu-se a confecção de lâminas por aposição para pesquisa de amastigotas. Nos órgãos com resultado negativo na pesquisa direta do parasito, e em todas as amostras de encéfalo, foi realizada a técnica de imunohistoquímica. A pesquisa direta de amastigotas foi positiva no baço e fígado de todos os animais infectados; 33,3% apresentaram o parasito em rim e pulmão, e 16,7% no coração. Quando realizada a pesquisa em encéfalo, formas parasitárias foram observadas em 83,3% (15/18) dos animais. A imunomarcação confirmou os resultados da pesquisa direta, exceto em duas amostras de tecido pulmonar e nas amostras de encéfalo. Mais estudos são necessários, para esclarecer o real papel do parasito no sistema nervoso central.(AU)
Assuntos
Animais , Leishmania/isolamento & purificação , Leishmaniose Visceral/diagnóstico , Mesocricetus/parasitologia , Sistema Nervoso Central/parasitologia , Encéfalo/parasitologia , Imuno-Histoquímica/métodos , Imuno-Histoquímica/veterinária , Baço/parasitologia , Fígado/parasitologia , Rim/parasitologia , Pulmão/parasitologia , Coração/parasitologiaRESUMO
INTRODUCTION: The work was conducted to study phlebotomine fauna (Diptera: Psychodidae) and aspects of American cutaneous leishmaniasis transmission in a forested area where Leishmania (Leishmania) amazonensis occurs, situated in the municipality of Bela Vista, State of Mato Grosso do Sul, Brazil. METHODS: The captures were conducted with modified Disney traps, using hamster (Mesocricetus auratus) as bait, from May 2004 to January 2006. RESULTS: Ten species of phlebotomine sandflies were captured: Brumptomyia avellari, Brumptomyia brumpti, Bichromomyia flaviscutellata, Evandromyia bourrouli, Evandromyia lenti, Lutzomyia longipalpis, Psathyromyia campograndensis, Psathyromyia punctigeniculata, Psathyromyia shannoni and Sciopemyia sordellii. The two predominant species were Ev bourrouli (57.3%) and Bi flaviscutellata (41.4%), present at all sampling sites. Two of the 36 hamsters used as bait presented natural infection with Leishmania. The parasite was identified as Leishmania (Leishmania) amazonensis. CONCLUSIONS: Analysis of the results revealed the efficiency of Disney traps for capturing Bichromomyia flaviscutellata and the simultaneous presence of both vector and the Leishmania species transmitted by the same can be considered a predictive factor of the occurrence of leishmaniasis outbreaks for the human population that occupies the location.
Assuntos
Insetos Vetores/classificação , Leishmania mexicana/isolamento & purificação , Psychodidae/classificação , Animais , Brasil , Cricetinae , Feminino , Humanos , Insetos Vetores/parasitologia , Leishmaniose Cutânea/transmissão , Masculino , Mesocricetus/parasitologia , Densidade Demográfica , Psychodidae/parasitologia , Estações do AnoRESUMO
INTRODUCTION: The work was conducted to study phlebotomine fauna (Diptera: Psychodidae) and aspects of American cutaneous leishmaniasis transmission in a forested area where Leishmania (Leishmania) amazonensis occurs, situated in the municipality of Bela Vista, State of Mato Grosso do Sul, Brazil. METHODS: The captures were conducted with modified Disney traps, using hamster (Mesocricetus auratus) as bait, from May 2004 to January 2006. RESULTS: Ten species of phlebotomine sandflies were captured: Brumptomyia avellari, Brumptomyia brumpti, Bichromomyia flaviscutellata, Evandromyia bourrouli, Evandromyia lenti, Lutzomyia longipalpis, Psathyromyia campograndensis, Psathyromyia punctigeniculata, Psathyromyia shannoni and Sciopemyia sordellii. The two predominant species were Ev bourrouli (57.3 percent) and Bi flaviscutellata (41.4 percent), present at all sampling sites. Two of the 36 hamsters used as bait presented natural infection with Leishmania. The parasite was identified as Leishmania (Leishmania) amazonensis. CONCLUSIONS: Analysis of the results revealed the efficiency of Disney traps for capturing Bichromomyia flaviscutellata and the simultaneous presence of both vector and the Leishmania species transmitted by the same can be considered a predictive factor of the occurrence of leishmaniasis outbreaks for the human population that occupies the location.
INTRODUÇÃO: O estudo foi realizado com o objetivo de estudar a fauna de flebotomíneos (Diptera: Psychodidae) e aspectos ligados à transmissão da leishmaniose tegumentar americana em uma área florestal com ocorrência de Leishmania (Leishmania) amazonensis, situada no município de Bela Vista, Estado do Mato Grosso do Sul, Brasil. MÉTODOS: As capturas de flebotomíneos foram realizadas utilizando-se armadilhas tipo Disney modificadas, com isca roedor, Mesocricetus auratus, no período de maio de 2004 a janeiro de 2006. RESULTADOS: As coletas resultaram na identificação de 10 espécies de Phlebotominae: Brumptomyia avellari, Brumptomyia brumpti, Bichromomyia flaviscutellata, Evandromyia bourrouli, Evandromyia lenti, Lutzomyia longipalpis, Psathyromyia campograndensis, Psathyromyia punctigeniculata, Psathyromyia shannoni e Sciopemyia sordellii. As duas espécies predominantes foram Ev bourrouli, com 57,3 por cento dos espécimes coletados, e Bi. flaviscutellata, representada por 41,4 por cento e que esteve presente em todos os locais amostrados. Dois hamsters sentinelas adquiriram a infecção natural, sendo os isolados identificados como Leishmania amazonensis. CONCLUSÕES: Os resultados mostram a eficiência das armadilhas Disney para captura de Bichromomyia flaviscutellata, e a presença simultânea de ambos, o vetor e a espécie de Leishmania por ele transmitida pode ser considerada um fator preditor da ocorrência de leishmaniose para a população humana que permanecer nesse local.
Assuntos
Animais , Cricetinae , Feminino , Humanos , Masculino , Insetos Vetores/classificação , Leishmania mexicana/isolamento & purificação , Psychodidae/classificação , Brasil , Insetos Vetores/parasitologia , Leishmaniose Cutânea/transmissão , Mesocricetus/parasitologia , Densidade Demográfica , Psychodidae/parasitologia , Estações do AnoRESUMO
The potential role of companion animals as reservoirs for zoonotic diseases has been recognised as a significant public health problem worldwide. Ancylostoma ceylanicum is the only ancylostomatidae species known for infecting human beings. This article aimed to compare the predatory capacity of predatory fungi isolates Duddingtonia flagrans (AC001), Monacrosporium thaumasium (NF34), Monacrosporium sinense (SF53) and Arthrobotrys robusta (I31) on A. ceylanicum infectious larvae (L(3)) in a 2% water-agar plate. There was no predatory capacity variation among the fungi tested (P>0.05) over the 7-day period experimental assay. When compared to the control (without fungi), there was a significant reduction (P<0.05) of 95.6%, 85.1%, 87.4% and 90.2% on the A. ceylanicum L(3) mean recovered from treatments with isolates AC001, NF34, SF53 and I31, respectively. Regarding linear regression coefficients, negative values were noted for treatments, therefore indicating A. ceylanicum non-predated larvae reduction over 7 days. In this work, all predatory fungi isolates were efficient at capturing and destroying in vitro the A. ceylanicum L(3); therefore being able to be used as biological controllers of such nematode.
Assuntos
Ancylostoma/microbiologia , Ancilostomíase/veterinária , Ascomicetos/fisiologia , Controle Biológico de Vetores/métodos , Ancilostomíase/terapia , Animais , Cricetinae , Humanos , Larva/microbiologia , Masculino , Mesocricetus/parasitologia , Zoonoses/microbiologiaRESUMO
The antinematode effect of tribendimidine (TBD) and its metabolites has been studied. A total of 107 hamsters were each infected with 250 Necator americanus third stage infective larvae (NaL3) for 25 days. In the first test, 75 hamsters were divided equally into 15 groups for determination of ED(50) and ED(90.) Among them, five groups were treated orally with TBD or its metabolite, p-(1-dimethylamino ethylimino)aniline (aminoamidine, deacylated amidantel, BAY d 9216, dADT), at single doses of 1, 2, 4, 8, and 16 mg/kg. The remaining five groups were administered with acetylated dADT (AdADT) at single oral doses of 8, 12, 18, 24, and 30 mg/kg. In the second test, 20 hamsters were equally divided into four groups. Two groups were treated intramuscularly with TBD and dADT at a single dose of 16 mg/kg, while in the remaining two groups, single intramuscular dose of AdADT 15 or 30 mg/kg was administered. In the third test, two groups of six hamsters were treated orally with terephthalaldehyde (TPAL) and terephthalic acid (TPAC) at a single dose of 1,000 mg/kg. Other 85 rats, each infected with 300 Nippostrongylus braziliensis third stage infective larvae (NbL3), were used in three tests. For determination of ED(50) and ED(90) in the first test, five groups of five rats were treated orally with TBD or dADT at single doses of 3.0, 4.2, 5.9, 8.2, and 11.5 mg/kg or 2.0, 2.9, 4.2, 6.1, and 8.8 mg/kg, respectively. In the second test, three groups of eight to nine rats were treated orally with TBD at a single 8.4-mg/kg dose (ED(90)) and AdADT 100 or 200 mg/kg, respectively. In the third test, two groups of four rats were treated orally with TPAL and TPAC at a single dose of 1,000 mg/kg. Twenty-four to 48 h post-treatment, all the feces of each hamster and rat were collected for recovery of worms expelled from the feces. Following this period, all of the animals were sacrificed, and the adult hookworm or N. braziliensis from small intestine and large intestine were recovered and counted for calculation of worm burden reduction. The results showed that the ED(50) and ED(90) for TBD, dADT, and AdADT determined in treatment of N. americanus-infected hamsters were 1.849 and 13.598, 3.922 and 54.354, as well as 20.966 and 51.633 mg/kg, respectively. In intramuscular administration of TBD and dADT at single dose of 16 mg/kg or AdADT 30 mg/kg, similar worm burden reductions of 71.4-76.3% were observed. Two other metabolites, i.e., TPAL and TPAC, exhibited no effect against N. americanus. The ED(50) and ED(90) for TBD and dADT determined in treatment of rats infected with N. braziliensis were 3.234 and 8.435, as well as 2.345 and 5.104 mg/kg. Oral administration of AdADT at a higher single dose of 100 or 200 mg/kg resulted in worm burden reductions of 11.9-46.3%, which was significantly lower than 84.5% of worm burden reduction obtained from rats treated with TBD 8.4 mg/kg. The results indicate that in oral administration, TBD exhibits slightly better effect against N. americanus in hamsters than dADT, but AdADT possesses less effect; TBD, dADT, and AdADT show promising effect in intramuscular treatment of N. americanus-infected hamsters; the effect of oral dADT against N. braziliensis in rats is somewhat better than TBD, while AdADT endorses poor effect; and TPAL and TPAC are ineffective metabolites of TBD against both species of nematodes.
Assuntos
Anti-Helmínticos/uso terapêutico , Mesocricetus/parasitologia , Necator americanus/efeitos dos fármacos , Necatoríase/tratamento farmacológico , Nippostrongylus/parasitologia , Fenilenodiaminas/uso terapêutico , Administração Oral , Animais , Anti-Helmínticos/administração & dosagem , Cricetinae , Modelos Animais de Doenças , Fezes/parasitologia , Injeções Intramusculares , Intestino Grosso/parasitologia , Intestino Delgado/parasitologia , Fenilenodiaminas/administração & dosagem , Ratos , Resultado do TratamentoRESUMO
The complete life cycle of the trematode Ascocotyle (Phagicola) longa (Digenea: Heterophyidae) is elucidated by natural observation validated by experimental infections. The natural first intermediate host of A. (P.) longa, an agent of human heterophyiasis in Brazil, is the cochliopid snail Heleobia australis (new first intermediate host). Metacercariae were found encysted in the body musculature, heart, stomach, liver, kidney, spleen, gonads and mesentery of mullets Mugil liza. Hamsters Mesocricetus auratus were experimentally infected with metacercariae of A. (P.) longa obtained from the mullets, and the adults recovered were used to infect the snails H. australis. Rediae and cercariae of A. (P.) longa are described for the first time. The ultrastructure of the tegument of A. (P.) longa shows a change in spination pattern from the cercaria with single-pointed spines to the metacercaria and adult with multipointed, brush-shaped spines. The life cycle of A. (P.) longa is related to estuaries and coastal lagoons where the recruitment of mugilid juveniles occurs. The high prevalence (100%) of A. (P.) longa encysted in the mullets examined within the urban area of Rio de Janeiro indicates the potentially great public health impact of the consumption of raw mullets.
Assuntos
Heterophyidae/crescimento & desenvolvimento , Estágios do Ciclo de Vida , Estruturas Animais/parasitologia , Animais , Brasil , Cricetinae , Doenças Transmitidas por Alimentos/parasitologia , Heterophyidae/ultraestrutura , Humanos , Mesocricetus/parasitologia , Microscopia , Microscopia Eletrônica de Varredura , Smegmamorpha/parasitologia , Caramujos/parasitologiaRESUMO
The life history of the trematode Pygidiopsis macrostomum Travassos, 1928 is described for the first time. Rediae and cercariae were obtained from naturally infected snails Heleobia australis (d Orbigny), a new first intermediate host. Metacercariae were found encysted in the mesenteries of three naturally infected guppies, Phalloptychus januarius (Hensel), Jenynsia multidentata (Jenyns) (new host records) and Poecilia vivipara Bloch and Schneider. Experimental infections were successfully completed in the intermediate hosts H. australis and Poe. vivipara reared in the laboratory and hamsters Mesocricetus auratus Waterhouse were utilised as a definitive host.
Assuntos
Heterophyidae/crescimento & desenvolvimento , Estágios do Ciclo de Vida/fisiologia , Mesocricetus/parasitologia , Poecilia/parasitologia , Caramujos/parasitologia , Animais , Cricetinae , Heterophyidae/ultraestrutura , Microscopia Eletrônica de Varredura , Poecilia/classificação , Estações do Ano , Caramujos/classificaçãoRESUMO
The life history of the trematode Pygidiopsis macrostomum Travassos, 1928 is described for the first time. Rediae and cercariae were obtained from naturally infected snails Heleobia australis (d´Orbigny), a new first intermediate host. Metacercariae were found encysted in the mesenteries of three naturally infected guppies, Phalloptychus januarius (Hensel), Jenynsia multidentata (Jenyns) (new host records) and Poecilia vivipara Bloch and Schneider. Experimental infections were successfully completed in the intermediate hosts H. australis and Poe. vivipara reared in the laboratory and hamsters Mesocricetus auratus Waterhouse were utilised as a definitive host.
Assuntos
Animais , Cricetinae , Heterophyidae/crescimento & desenvolvimento , Estágios do Ciclo de Vida/fisiologia , Mesocricetus/parasitologia , Poecilia/parasitologia , Caramujos/parasitologia , Heterophyidae/ultraestrutura , Microscopia Eletrônica de Varredura , Poecilia/classificação , Estações do Ano , Caramujos/classificaçãoRESUMO
Taenia solium causes human neurocysticercosis, a public health problem in Mexico and other developing countries. Surprisingly, tapeworm carriers are very rarely found and in necropsy studies practically no tapeworms have been reported. In this paper we analyze the possibility that, after the death of the host, tapeworms could easily be destroyed in the intestine. Our experiments, performed in the hamster model, suggest that the absence of tapeworms in human intestine during necropsy is not due to postmortem digestion.
Assuntos
Mesocricetus/fisiologia , Mesocricetus/parasitologia , Mudanças Depois da Morte , Taenia solium/fisiologia , Teníase/diagnóstico , Teníase/parasitologia , Animais , Cricetinae , Digestão/fisiologia , Taenia solium/isolamento & purificaçãoRESUMO
Histopathological and functional changes in the pancreas were studied in 94 hamsters infected and reinfected with Trypanosoma cruzi VIC strain and in 73 non-infected normal controls. Infection in each animal was verified by microhematocrit, hemoculture, specific peroxidase anti-peroxidase, polymerase chain reaction and seroagglutination. Blood glucose and insulin were determined. The number of islets per section and the number of islet cells marked with antibodies were counted. Insulitis, neuritis, fibrosis, atrophy and inflammatory infiltrates were evaluated. Experimental chagasic infection caused pancreatitis similar to human Chagas' disease, involving acini, islets and nerves, with atrophy and fibrosis, although without correlation to the number of reinfections. Erratic blood glucose levels and a tendency to hypoinsulinemia were observed in infected animals. During the acute phase, the number of somatostatin and pancreatic polipeptide producer islet cells was lower in infected hamsters, which was eventually related to changes in blood sugar levels and hypoinsulinemia. Our findings favor the hypothesis of the existence of an endocrine form of chronic chagasic infection.
Assuntos
Doença de Chagas/patologia , Pâncreas/metabolismo , Pâncreas/patologia , Trypanosoma cruzi/patogenicidade , Animais , Doença de Chagas/parasitologia , Cricetinae , Humanos , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/patologia , Mesocricetus/parasitologia , Pancreatite/parasitologia , Pancreatite/patologiaRESUMO
Strobilae from Taenia crassiceps (WFU strain) were obtained from outbred hamsters (Mesocricetus auratus) by feeding them viable metacestodes maintained by intraperitoneal passage in female Balb/c mice. Mature and gravid proglottids from strobilae were recovered from hamster intestines and fixed for light and electron microscopy. By light microscopy, the expected structure of taeniid proglottids was observed. Ultrastructural analysis of ten proglottids showed that testicular follicles and vas deferens contained filiform spermatids, with a single axoneme, and an elongated helicoidal nucleus inserted between the axoneme and the spiraled cortical microtubules. At the apical cone, a single crest-like body was found and mature spermatids also exhibited transverse intracytoplasmic walls. The morphology and characters of the spermatids in T. crassiceps conform to type III spermiogenesis, which has been described in other taeniids.
Assuntos
Mesocricetus/parasitologia , Espermatogênese/fisiologia , Espermatozoides/ultraestrutura , Taenia/fisiologia , Animais , Animais não Endogâmicos , Cricetinae , Feminino , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Espermatozoides/fisiologia , Taenia/classificação , Taenia/isolamento & purificaçãoRESUMO
Golden hamsters ( Mesocricetus auratus) were infected with Taenia solium metacestodes dissected from infected pig meat. Adult worms were collected from hamster intestines of animals killed 5-60 days post-infection (dpi), incubated in RPMI 1640 medium with or without colchicine, fixed and processed for transmission electron microscopy (TEM). Sections for light microscopy from 40 different blocks with scolex, immature and mature proglottids were photographed. Thin sections were cut from 25 selected blocks, examined and photographed with TEM. Metaphase mitosis figures were observed in the subtegument of the germinative tissue and interpreted as germ cell precursors. In immature proglottids (20 dpi), discrete cell clusters of three to four cells surrounded by a thin cytoplasmic envelope were identified along the inner border of the lateral excretory ducts. These were also observed in more mature proglottids (40-60 dpi) as clusters of eight cells enclosed in a cytoplasmic envelope, with nuclei of spermatogonia exhibiting the synaptolems of primary meiotic cells. In mature proglottids from 45 dpi, a large number of spermatocyte lobules were found, exhibiting different stages of spermatogenesis from primary spermatocytes to mature filiform spermatids with a single axoneme, annular nucleus and spiral cortical microtubules, similar to spermatozoa described for type III spermiogenesis of species of the family Taeniidae. All mature spermatocyte lobules were enclosed in a highly organized cellular envelope and surrounded by a basal lamina. The envelopes contained a number of distinct organelles, seen in cross-section as discrete lattices of microtubules located between two layers of plasma membrane, as well as thickened furled cytoplasm with numerous strands of rough endoplasmic reticulum and pockets of microtubules.
Assuntos
Espermatócitos/ultraestrutura , Espermatogônias/ultraestrutura , Taenia solium/ultraestrutura , Animais , Animais não Endogâmicos , Cricetinae , Cisticercose/parasitologia , Enteropatias Parasitárias/parasitologia , Estágios do Ciclo de Vida , Masculino , Mesocricetus/parasitologia , Taenia solium/isolamento & purificaçãoRESUMO
In this study we characterised metacyclogenesis in axenic culture of Leishmania (Viannia) braziliensis, the causative agent of mucocutaneous leishmaniasis in the New World. Metacyclogenesis of other species of Leishmania has been shown by morphological changes as well as molecular modifications in the lipophosphoglycan, the major cell surface glycoconjugate of the promastigotes. In order to obtain metacyclic forms of L. braziliensis we tested a panel of different lectins. Our results showed that Bauhinia purpurea lectin facilitated the purification of metacyclic promastigotes from stationary-phase culture by negative selection. The B. purpurea non-agglutinated promastigotes had a slender short cell body and long flagella, typical of metacyclic morphology. The ultrastructural analysis showed that B. purpurea non-agglutinated promastigotes have a dense and thicker glycocalyx. They are resistant to complement lysis, and highly infective for macrophage in vitro and hamsters in vivo. Contrary to procyclic promastigotes, B. purpurea non-agglutinated forms were poorly recognised by sand fly gut epithelial cells. These results suggest that the B. purpurea non-agglutinated promastigotes are the metacyclic forms of L. braziliensis.
Assuntos
Proteínas do Sistema Complemento/imunologia , Leishmania braziliensis/crescimento & desenvolvimento , Leishmania braziliensis/imunologia , Macrófagos/parasitologia , Mesocricetus/parasitologia , Lectinas de Plantas/imunologia , Aglutinação , Animais , Cricetinae , Leishmania braziliensis/isolamento & purificação , Leishmania braziliensis/ultraestrutura , Macrófagos/imunologia , Mesocricetus/imunologia , CamundongosRESUMO
Helminth fauna of conventionally maintained hamsters from institutional animal houses that supply the research community with laboratory animals and from an openly kept control group, randomly purchased in a pet shop in the State of Rio de Janeiro, were evaluated and compared. Necropsied animals from institutional suppliers were infected with the oxyurid nematodes Syphacia criceti and S. mesocriceti and with the cestode Rodentolepis nana; those from the pet shop were infected with S. mesocriceti and R. nana. These are the first morphometric data that are based on Brazilian samples of these species parasitizing hamsters. Mesocricetus auratus is a newly recorded host for S. criceti, previously recovered from Oryzomys subflavus and Calomys callosus in Brazil. The potential of pet and laboratory hamsters in the spreading of helminth infections to humans is also considered.