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1.
PLoS One ; 12(7): e0181188, 2017.
Article in English | MEDLINE | ID: mdl-28704561

ABSTRACT

Species co-existence depends on how organisms utilize their environment and resources. When two sympatric species are similar in some ecological requirements, their coexistence may arise from differences in resource use over time and/or space. Interactions among coexisting marsupials remain poorly understood, especially in the Neotropics. Here we combine spatial niche measurements, individual-resource networks, and isotopic niche approaches, to investigate the ecological strategies used by the Neotropical marsupials Didelphis aurita and Metachirus nudicaudatus to co-occur in an area of Serra do Mar State Park (southeast of Brazil). Both individual-resource networks and isotopic niche approaches indicate similar patterns of omnivory for both species. Isotopic analysis showed the species' trophic niche to be similar, with 52% of overlap, and no differences between proportional contributions of each resource to their diets. Moreover, individual-resource network analysis found no evidence of diet nestedness or segregation. The trophic niche overlap observed was associated with spatial segregation between species. Despite using the same area over the year, D. aurita and M. nudicaudatus exhibited spatial segregation among seasons. These results illustrate that the detection of spatial segregation is scale-dependent and must be carefully considered. In conclusion, our findings provide a new perspective on the ecology of these two Neotropical marsupials by illustrating how the association of distinct but complementary methods can be applied to reach a more complete understanding of resource partitioning and species coexistence.


Subject(s)
Animal Distribution , Diet , Ecosystem , Feeding Behavior , Marsupialia/physiology , Animals , Marsupialia/classification
2.
Acta Parasitol ; 60(3): 515-24, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26204011

ABSTRACT

The abundance of parasites on a host can be affected by several factors; in this study, we investigated the influence of sex and body size of the host rodent Oligoryzomys nigripes on the abundance of ectoparasitic mites (Acari: Mesostigmata). The generalized linear model indicated that body size (indicative of age) of the host rodent O. nigripes significantly contributed to the variation in the abundance of mites on host rodents at the Experimental Station of Itirapina. This trend of increased parasitism on hosts with larger body sizes may be linked to the fact that larger individuals are able to support the coexistence of a larger number of parasites, and being more mobile, are more exposed to infection by parasites.


Subject(s)
Body Size , Mite Infestations/parasitology , Mites/growth & development , Parasite Load , Sigmodontinae/anatomy & histology , Sigmodontinae/parasitology , Animals , Female , Male , Sex Factors
3.
Rev. patol. trop ; 44(1): 56-66, 2015. ilus, tab
Article in English | LILACS | ID: lil-758565

ABSTRACT

Schistosomiasis is a severely neglected disease with a wide geographical distribution. It affectsapproximately 210 million people in the world and at least 800 million people live in risk areas.The search for new drugs to treat this parasitosis is significant due to the appearance of strains of theworm that are resistant to the currently available drugs. The retrieval of compounds extracted fromplants that act on these parasites has increased scientific investigation of this subject. The presentstudy demonstrates, in vitro and in vivo, the action of crude extract of Piper tuberculatum on adultSchistosoma mansoni. The extract was shown to be quite effective in the in vitro tests, causing softtissue alterations and acting on the reproductive system of females and the mortality of the worms,with a greater effect on males. The in vivo experiment was performed with infected Mus musculusand a decrease in the number of eggs in the first and second oogram stages was found, suggestingaction on oviposition...


A esquistossomose, doença negligenciada grave e de larga distribuição geográfica, atinge cerca de210 milhões de pessoas no mundo e ao menos 800 milhões vivem em área de risco. A busca de novosmedicamentos para o tratamento desta parasitose é relevante em razão do aparecimento de linhagensdo verme resistentes aos fármacos disponíveis. A obtenção de compostos extraídos de plantas comação sobre parasitos tem incrementado a investigação científica sobre este assunto. O presentetrabalho mostra a ação in vitro e in vivo do extrato bruto de Piper tuberculatum sobre adultosde Schistosoma mansoni. O extrato mostrou-se bastante eficaz nos ensaios in vitro, provocandoalterações tegumentares, tendo ação no sistema reprodutor das fêmeas e na mortalidade dos vermes com maior ação sobre os machos. Como resultado em experimentos in vivo, realizados em Musmusculus infectados, observou-se a diminuição do número de ovos de 1º e 2º estágios em oogramas,o que sugere uma ação na postura de ovos...


Subject(s)
Animals , Rats , Animals, Laboratory , Schistosomiasis mansoni/diagnosis , Schistosomiasis mansoni/epidemiology
4.
Exp Parasitol ; 139: 63-72, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24602876

ABSTRACT

Although its efficiency against all Schistosoma species, praziquantel (PZQ) shows low efficacy against schistosomula and juvenile stages. The potential for development of resistance to PZQ has justified the search for new alternative chemotherapies. In this scenario, studies to new formulations, more comprehensive and without adverse effects, are being conducted. One viable and promising treatment is the study of medicinal plants as a new approach to the experimental treatment for Schistosomiasis. Amongst all the variety of the medicinal species studied, we can highlight Baccharis trimera (Less) DC, known as "Carqueja-amarga". This paper not only describes the effect of crude dichloromethane extract (DE) and aqueous fraction (AF) obtained from B. trimera, in vitro but also is the first one that investigates the in vivo efficacy of B. trimera against schistosomula, juvenile and adult worms of Schistosoma mansoni BH strain. In the experiment, mice were treated with DE, AF and PZQ (40 and 200mg/kg) over the period of larval development (3 and 30 post-infection; pi), and adult worms (60days post-infection; pi). The in vitro results show that the DE and AF effects are dose-dependents, being the 130µg/mL the most effective one in a shorter period of incubation. The exposure of the in vitro samples over adult parasites were able to inhibit 100% of the oviposition in females. Likewise caused the mortality of the parasites with morphological alterations on the tegument, on the suckers, oral and acetabulum, in both males and females after 6-72h of exposure. Additionally, the in vivo treatments against juvenile and adult infection were more effective compared to the control group untreated. Administrations of AF and DE in day 30pi (juvenile worms) show female worm total burden reductions of 75% and 68% respectively. At the same period of infection reductions of respectively 98% and 97% egg/g in the faeces were seen. In relation to the different egg developmental stages (oogram), the results showed significant reductions, due to the reduction in the number of worms, especially the females. In conclusion, B. trimera exhibits major schistosomicidal effects in vivo against immature and adult worms of S. mansoni, opening up perspectives for future researches on substance or compound isolation and the elucidation of its mechanisms of action.


Subject(s)
Anthelmintics/pharmacology , Baccharis/chemistry , Plant Extracts/pharmacology , Schistosoma mansoni/drug effects , Schistosomiasis mansoni/drug therapy , Animals , Anthelmintics/therapeutic use , Anthelmintics/toxicity , Chlorocebus aethiops , Feces/parasitology , Female , Liver/parasitology , Liver/pathology , Male , Mice , Mice, Inbred BALB C , Microscopy, Electron, Scanning , Parasite Egg Count , Plant Extracts/therapeutic use , Plant Extracts/toxicity , Praziquantel/pharmacology , Praziquantel/therapeutic use , Schistosoma mansoni/ultrastructure , Schistosomiasis mansoni/parasitology , Schistosomiasis mansoni/pathology , Vero Cells
5.
Parasitol Res ; 113(1): 217-22, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24189973

ABSTRACT

Since insect species are poikilothermic organisms, they generally exhibit different growth patterns depending on the temperature at which they develop. This factor is important in forensic entomology, especially for estimating postmortem interval (PMI) when it is based on the developmental time of the insects reared in decomposing bodies. This study aimed to estimate the rates of development, viability, and survival of immatures of Sarcophaga (Liopygia) ruficornis (Fabricius 1794) and Microcerella halli (Engel 1931) (Diptera: Sarcophagidae) reared in different temperatures: 10, 15, 20, 25, 30, and 35 ± 1 °C. Bovine raw ground meat was offered as food for all experimental groups, each consisting of four replicates, in the proportion of 2 g/larva. To measure the evolution of growth, ten specimens of each group were randomly chosen and weighed every 12 h, from initial feeding larva to pupae, and then discarded. Considering the records of weight gain, survival rates, and stability of growth rates, the range of optimum temperature for the development of S. (L.) ruficornis is between 20 and 35 °C, and that of M. halli is between 20 and 25 °C. For both species, the longest times of development were in the lowest temperatures. The survival rate at extreme temperatures (10 and 35 °C) was lower in both species. Biological data such as the ones obtained in this study are of great importance to achieve a more accurate estimate of the PMI.


Subject(s)
Entomology/methods , Forensic Sciences/methods , Sarcophagidae/growth & development , Temperature , Animals , Cattle , Larva/growth & development , Meat , Pupa/growth & development
6.
Interdiscip Perspect Infect Dis ; 2012: 894940, 2012.
Article in English | MEDLINE | ID: mdl-23209457

ABSTRACT

The pathogenesis of three different Schistosoma mansoni strains from the Brazilian states of Minas Gerais (BH strain) and São Paulo (SJ and SD strains) was evaluated in experimentally infected mice. Observations of the most severe clinical cases among local patients treated (SD strain) in the city of Campinas (São Paulo, Brazil) formed the basis of this study. Mice were used as definitive hosts and were infected with cercariae from Biomphalaria tenagophila (SJ and SD strains) and Biomphalaria glabrata (BH strains). The parameters analyzed were as follows: number of S. mansoni eggs in mice feces; number of granulomas per tissue area in liver, spleen, lungs, pancreas, and ascending colon; measurements of hepatic and intestinal granulomas; number of adult worms; and measurements of trematode eggs. The comparison among the three strains indicated that the SD strain, isolated in Campinas, presented a higher worm recovery relative to the number of penetrating cercariae. In addition, when compared to the SJ and BH strains, the SD strain demonstrated similar pathogenicity to the BH strain, with a greater quantity of granulomas in the viscera, as well as larger granulomas and eggs. Furthermore, a greater quantity of trematode eggs was also shed in the feces.

7.
Interdiscip Perspect Infect Dis ; 2012: 953524, 2012.
Article in English | MEDLINE | ID: mdl-23193397

ABSTRACT

The increased pathogenesis of the Schistosoma mansoni BH strain compared with the SJ strain has been attributed to the number of granulomas formed in experimental infections, which increase the mortality in definitive hosts. The aim of the present study was to investigate the development of granulomas around the eggs of the S. mansoni BH and SJ strains and to determine whether this host reaction was strain specific. Four experimental groups were analyzed. Two groups contained mice inoculated in the caudal vein with eggs from the S. mansoni BH or SJ strains and the other two contained mice that were infected with cercariae of the BH strain prior to being inoculated with eggs. The number of granulomas per tissue area in the lungs and liver, as well as the size of the granulomas, was analyzed to characterize the response to schistosome infection. The largest granulomatous responses were observed around eggs of the BH strain. Granulomas covered a larger area in the lungs of mice that were previously infected with cercariae and subsequently inoculated with eggs of the BH strain. These results indicated that specific granulomatous responses occurred following an infection with the BH and SJ strains of S. mansoni.

8.
Parasitology ; 139(13): 1749-56, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22906797

ABSTRACT

Phylogenetic and geographical overlaps in host distributions influence the compositional similarity of ectoparasite fauna in a host-parasite system. In these systems, hosts that are more closely related (phylogenetically) are expected to share more parasitic species than more distantly related hosts. Similarly, hosts sharing a larger geographical distribution overlap are expected to have similar ectoparasites. This study investigated the influence of phylogeny (divergence time) and geographical overlap of some neotropical sigmodontine rodent species on the similarities among their ectoparasite fauna (Mesostigmata and Siphonaptera), using a partial Mantel test. Divergence time was the only significant factor that influenced the similarity among the ectoparasites, when mites and fleas were analysed together. Host species that had diverged more recently displayed ectoparasite fauna that were similar. The similarities of the flea species showed similar results in both separate and joint analyses, but neither phylogenetic nor geographical overlap influenced the similarity in mite species. Fleas were shown to be more host-specific than were mesostigmate mites, probably because of the increased influence of host phylogeny.


Subject(s)
Ectoparasitic Infestations/parasitology , Phylogeny , Rodent Diseases/parasitology , Sigmodontinae/parasitology , Animals , Biodiversity , Geography , Host Specificity , Host-Parasite Interactions , Time Factors
9.
Exp Parasitol ; 132(2): 135-43, 2012 Oct.
Article in English | MEDLINE | ID: mdl-22771865

ABSTRACT

Schistosomiasis is a chronic parasitic disease caused by the trematode species Schistosoma mansoni. Chemotherapy is the only immediate recourse to minimize the prevalence and incidence of this disease worldwide. At present, praziquantel (PZQ) is the drug of choice for the treatment of all forms of schistosomiasis. However, dependence on a single drug is concern because some strains can become resistant. In this context, medicinal plants become potential candidates as sources of new drug prototypes. This study provides findings on the schistosomicidal activity of the essential oil of Baccharis trimera in in vitro assays. During the assays parameters such as motility of adult worms, oviposition, morphological changes on the tegument and especially the mortality rate of adult worms of the BH strain were evaluated. The assays, which were carried out with four concentrations - 24, 48, 91 and 130 µg/mL - of the essential oil, have shown a promising activity regarding the parameters under study. It was possible to notice a significant decline in the motility of the worms and a mortality rate of 100% 30 h after they had been exposed to the essential oil in the concentration of 130 µg/mL. Male worms were more susceptible, producing a dose-response effect within a smaller exposition period than female worms. In what refers to morphological changes, the essential oil of B. trimera induced a peeling on the tegument surface, as well as the destruction of tubercles and spines, which resulted in smooth areas on the body surface. The essential oil also caused tegument destruction in female worms, in addition to destruction of the oral and acetabular suckers. It is the first time that the schistosomicidal activity has been reported for essential oil of B. trimera (less) DC.


Subject(s)
Baccharis/chemistry , Oils, Volatile/pharmacology , Schistosoma mansoni/drug effects , Schistosomicides/pharmacology , Animals , Biomphalaria , Cell Line , Dose-Response Relationship, Drug , Female , Gas Chromatography-Mass Spectrometry , Humans , Keratinocytes/drug effects , Male , Mice , Microscopy, Electron, Scanning , Movement/drug effects , Oils, Volatile/chemistry , Oils, Volatile/therapeutic use , Oviposition/drug effects , Plant Extracts/chemistry , Plant Extracts/pharmacology , Plant Extracts/therapeutic use , Schistosoma mansoni/physiology , Schistosoma mansoni/ultrastructure , Schistosomiasis mansoni/drug therapy , Schistosomicides/therapeutic use , Sex Factors , Specific Pathogen-Free Organisms
10.
Parasitol Res ; 111(4): 1701-6, 2012 Oct.
Article in English | MEDLINE | ID: mdl-22740295

ABSTRACT

Various factors can affect the parasite distribution on a host. In this study, the influence of sex, body size, and locality of a rodent host, Oligoryzomys nigripes, on lice abundance was investigated. A generalized linear model indicated that the sex and locality of O. nigripes significantly contributed to the variation in lice abundance on the host. The male bias of lice parasitizing the rodent host O. nigripes may be associated with intersexual differences in physiology and behavior, while locality differences in lice abundance may be associated with differences in host density and diversity between the two localities sampled. Studies of host-parasite associations improve the understanding of the ecology of infectious diseases, as well as the evolution of these host-parasite interactions.


Subject(s)
Ectoparasitic Infestations/veterinary , Parasite Load , Phthiraptera/growth & development , Rodent Diseases/epidemiology , Rodent Diseases/parasitology , Sigmodontinae/parasitology , Animals , Brazil/epidemiology , Ectoparasitic Infestations/epidemiology , Ectoparasitic Infestations/parasitology , Female , Geography , Male , Sex Factors
11.
Forensic Sci Int ; 220(1-3): 27-32, 2012 Jul 10.
Article in English | MEDLINE | ID: mdl-22341241

ABSTRACT

This study aimed to determine the effect of cocaine on the development and growth of immature and adult blowflies, in an attempt to better understand the impacts of such effects on postmortem interval (PMI) estimation. Twice the lethal dose of cocaine was injected into rabbits. The control animals were injected only with saline solution. Experimental and control rabbits were autopsied, and portions of their livers were exposed to newly eclosed larvae of Chrysomya putoria and Chrysomya albiceps. Larvae were weighed individually every 6 h, up 54 h of exposure. The larvae were then placed on an artificial diet to continue their development. Pupariation time, adult emergence and adult longevity were also analysed. The larvae of both species that fed on the cocaine-containing livers developed faster than those that fed on the livers of the control animals, leading to the conclusion that cocaine influences and stimulates larval growth. The difference in growth between the control and treated flies was best observed from 12 h of exposure onward. This finding has important implications for forensic investigations.


Subject(s)
Cocaine/pharmacology , Diptera/drug effects , Diptera/growth & development , Feeding Behavior , Narcotics/pharmacology , Animals , Entomology , Forensic Pathology , Larva/drug effects , Larva/growth & development , Liver/pathology , Postmortem Changes , Pupa/drug effects , Pupa/growth & development , Rabbits , Time Factors
12.
Rev. bras. entomol ; 53(2): 314-317, June 2009. mapas
Article in English | LILACS | ID: lil-521146

ABSTRACT

The prevalence of Cuterebra simulans bot fly parasitism on marsupial Gracilinanus microtarsus was compared between sexes and seasons of the year. No significant difference was observed between females and males but prevalence was higher in warm-wet season than cool-dry season. This pattern agree with observations of others studies with oestrids flies in southern Neotropical areas, suggesting the occurrence of latitudinal change in the peak of bot flies reproductive activity related to seasons of the year along these systems. This is the first record of C. simulans larvae parasitism on G. microtarsus and its occurrence in southern areas of the Neotropical region.


A prevalência de parasitismo das larvas da mosca Cuterebra simulans no marsupial Gracilinanus microtarsus foi comparada entre os sexos e estações do ano. Machos e fêmeas não apresentaram diferenças significativas, mas a prevalência de parasitismo foi mais elevada na estação quenteúmida que na estação fria-seca. Este padrão está de acordo com as observações de outros estudos com moscas da família Oestridae realizados nas áreas ao sul da região Neotropical, sugerindo a ocorrência de mudanças latitudinais nos picos de atividades reprodutivas destas moscas em relação às estações do ano ao longo destes sistemas. Este também é o primeiro registro da ocorrência de C. simulans em áreas mais ao sul da região Neotropical e do parasitismo de suas larvas em G. microtarsus.


Subject(s)
Animals , Male , Female , Diptera/physiology , Opossums/parasitology , Hypodermyiasis , Myiasis , Brazil , Grassland , Larva
13.
Ciênc. rural ; 38(6): 1694-1699, jul.-set. 2008. tab
Article in English | LILACS | ID: lil-492011

ABSTRACT

Diseases transmitted by ticks have been an important health problem all over the world. Brazilian Spotted Fever (BSF) stands for a serious epidemiological concern due to the high mortality rates pointed out. Capybaras are commonly incriminated as possible reservoirs in the BSF transmission cycle. In the last decades the numbers of these animals raised sharply and they have invaded human areas. They intensify the contact between ticks and humans beings. This study aim is to contribute to the possible role performed for this rodent in the BSF epidemiology in some areas located in Campinas region, São Paulo. Cabybaras infected by rickettsiae of BSF group were studied through the analysis of the frequencies of BSF-group rickettisae antibodies titer = 64 by indirect immunofluorescence test (IFA), and data from human cases epidemiological surveillance. The serum frequency positiveness varied greatly according to areas where animals were captured. However it was found serum positiviness only in the areas where human cases of BSF were reported. These findings suggest the capybara may be seen as sentinel animal. Due to presence of serological cross reactivity between microorganisms belonging to SF group, the results must be interpreted carefully and additional methods to distinguish pathogenic rickettsiae are required in our country.


Doenças transmitidas por carrapatos vêm sendo um importante problema de saúde pública no mundo. A Febre Maculosa Brasileira (FMB) representa um sério risco epidemiológico devido às altas taxas de letalidade apresentadas. As capivaras são freqüentemente incriminadas como possíveis reservatórios no ciclo de transmissão da FMB. Nas últimas décadas o número desses animais cresceu intensamente e eles invadiram os espaços humanos. As capivaras intensificam o contato entre carrapatos e seres humanos na medida em que se apresentam muito infestadas por estes parasitos. O objetivo deste estudo é contribuir para o conhecimento do possível papel desempenhado por este roedor na epidemiologia da FMB em algumas áreas da região de Campinas, SP. Foi estudada a infecção das capivaras por rickettsias do grupo da FMB, por meio da análise das freqüências de anticorpos contra este grupo, nestes animais, e dados da vigilância epidemiológica de casos humanos. A freqüência desses anticorpos variou amplamente entre as localidades, entretanto, só foram encontrados soros com anticorpos com titulagem =64 naquelas onde havia notificação de casos humanos. Estes achados sugerem que a capivara poderá ser um animal sentinela. No entanto, devido à ocorrência de reação cruzada entre os microorganismos do grupo de FM estes resultados devem ser interpretados com cautela e são necessários métodos capazes de distinguir rickettsias patogênicas.


Subject(s)
Animals , Tick-Borne Diseases/veterinary , Rocky Mountain Spotted Fever/veterinary , Rickettsia , Rodentia , Serology , Ticks
14.
Rev Soc Bras Med Trop ; 39(1): 68-71, 2006.
Article in Portuguese | MEDLINE | ID: mdl-16501770

ABSTRACT

The city of Campinas is located in an endemic area for Brazilian spotted fever in São Paulo State, where several cases have recently occurred. Capybaras have been associated with the cycle of this disease, for they present positive serology and serve as host for ticks of the genus Amblyomma, the main vectors of Brazilian spotted fever. Ticks were collected both from Capybaras and from the vegetation in the city park Lago do Café, located in the urban area of Campinas City, SP, a site associated with suspected human cases of Brazilian spotted fever. The ticks collected were examinated for the presence of rickettsiae using polymerase chain reaction and the haemolymph test. Through analysis of the gene gltA nucleotide sequence, adults of Amblyomma cajennense and Amblyomma cooperi were found to be infected with the non pathogenic Rickettsia bellii. However, no rickettsiae of the Spotted Fever Group were detected. These results indicate that the role of capybaras as reservoirs of rickettsiae of the Spotted Fever Group is still uncertain and further studies are required.


Subject(s)
Disease Reservoirs/veterinary , Disease Vectors , Ixodidae/microbiology , Rickettsia/isolation & purification , Rodentia/parasitology , Animals , Brazil/epidemiology , Endemic Diseases , Female , Humans , Male , Polymerase Chain Reaction , Rickettsia/classification , Rickettsia/genetics , Rickettsia Infections/epidemiology , Rickettsia Infections/transmission , Urban Population
15.
Rev. Soc. Bras. Med. Trop ; 39(1): 68-71, jan. -fev. 2006.
Article in Portuguese | LILACS, Sec. Est. Saúde SP | ID: lil-422087

ABSTRACT

O Município de Campinas situa-se em região endêmica para febre maculosa brasileira do Estado de São Paulo, onde vários casos desta doenca vem ocorrendo. Capivaras têm sido associadas ao ciclo dessa riquetsiose por apresentarem sorologia positiva e serem hospedeiras de carrapatos Amblyomma spp principais vetores da doenca. Carrapatos foram coletados no parque urbano do Lago do Café, Campinas, SP, local associado a casos humanos suspeitos de febre maculosa brasileira, sobre a vegetacão e das capivaras ali presentes, e pesquisados quanto à presenca de riquétsias pela reacão em cadeia da polimerase e pelo teste de hemolinfa. Adultos de Amblyomma cajennense e Amblyomma cooperi albergavam Rickettsia bellii, não patogênica, identificada pela análise das seqüências de nucleotídeos do gene gltA, porém, não foram constatadas riquétsias do Grupo da Febre Maculosa. Estes resultados associados à ausência de um isolado de riquétsias do Grupo da Febre Maculosa de capivaras indicam que seu papel, enquanto reservatório, necessita de maior investigacão.


Subject(s)
Animals , Humans , Male , Female , Disease Reservoirs/veterinary , Disease Vectors , Ixodidae/microbiology , Rickettsia/isolation & purification , Rodentia/parasitology , Brazil/epidemiology , Endemic Diseases , Polymerase Chain Reaction , Rickettsia Infections/epidemiology , Rickettsia Infections/transmission , Rickettsia/classification , Rickettsia/genetics , Urban Population
16.
Rev. Soc. Bras. Med. Trop ; 38(5): 387-390, set.-out. 2005. tab
Article in Portuguese | LILACS | ID: lil-409471

ABSTRACT

Gerações de Biomphalaria glabrata e Biomphalaria tenagophila selecionadas geneticamente para resistência e suscetibilidade ao Schistosoma mansoni das linhagens BH e SJ foram utilizadas no estudo da adaptação do trematódeo ao hospedeiro intermediário. As gerações dos planorbídeos foram obtidas por autofecundação dos moluscos que se apresentaram suscetíveis ou resistentes após a exposição aos miracídios de Schistosoma mansoni. Para Biomphalaria glabrata foram obtidas as gerações: Parental, F1S (Suscetível), F1R (Resistente), F2S e F2R. Para a Biomphalaria tenagophila foram estudadas as gerações: Parental, F1S, F1R e F50S. A comparação das taxas de infecção apresentadas pelas diferentes gerações mostrou que, em ambas as espécies, o aumento da suscetibilidade foi mais facilmente obtido do que o aumento da resistência. A dificuldade em aumentar a resistência do molusco ao S. mansoni tem fortes implicações epidemiológicas.


Subject(s)
Animals , Biomphalaria/genetics , Disease Vectors , Selection, Genetic , Schistosoma mansoni/physiology , Biomphalaria/parasitology , Host-Parasite Interactions/genetics
17.
Rev Soc Bras Med Trop ; 38(5): 387-90, 2005.
Article in Portuguese | MEDLINE | ID: mdl-16172752

ABSTRACT

Generations of Biomphalaria glabrata and Biomphalaria tenagophila selected genetically for resistance and susceptibility to Schistosoma mansoni of strains BH and SJ were used in a study of the trematode adaptation to the intermediate host. Descendants of the planorbids were obtained by self-fertilization of the mollusks that became susceptible or resistant after exposure to the miracidia of Schistosoma mansoni. For Biomphalaria glabrata they were obtained from the following generations: Parental, F1S (Susceptible), F1R (Resistant), F2S and F2R. For Biomphalaria tenagophila the studied generations were: Parental, F1S, F1R and F50S. The comparison of the infection rates presented by the different generations showed that the increase in susceptibility was more easily obtained in both species. The difficulty in increasing the resistance of the mollusks to Schistosoma mansoni has important epidemiologic implications.


Subject(s)
Biomphalaria/genetics , Disease Vectors , Schistosoma mansoni/physiology , Selection, Genetic , Animals , Biomphalaria/parasitology , Host-Parasite Interactions/genetics
18.
Mem. Inst. Oswaldo Cruz ; 98(8): 1071-1076, Dec. 2003. tab
Article in English | LILACS | ID: lil-355751

ABSTRACT

A study of the associations between small mammals and fleas was undertaken in three areas of the Atlantic Forest in Souhtheastern Brazil: Serra da Fartura, SP, Serra da Bocaina, SP, and Itatiaia, RJ. Trapping of small rodents and marsupials was done every 3 months during 2 years, from June 1999 to May 2001. A total 502 rodents (13 species) and 50 marsupials (7 species) were collected, and 185 hosts out of 552 (33.5 percent) captured in the traps were parasitized by 327 fleas belonging to 11 different species. New host records were determined for several flea species, and 5 significant associations between fleas and hosts were also found.


Subject(s)
Animals , Ectoparasitic Infestations , Marsupialia , Rodent Diseases , Rodentia , Siphonaptera , Brazil , Ectoparasitic Infestations , Host-Parasite Interactions , Prevalence , Rodent Diseases
19.
Mem Inst Oswaldo Cruz ; 98(8): 1071-6, 2003 Dec.
Article in English | MEDLINE | ID: mdl-15049093

ABSTRACT

A study of the associations between small mammals and fleas was undertaken in three areas of the Atlantic Forest in Southeastern Brazil: Serra da Fartura, SP, Serra da Bocaina, SP, and Itatiaia, RJ. Trapping of small rodents and marsupials was done every 3 months during 2 years, from June 1999 to May 2001. A total 502 rodents (13 species) and 50 marsupials (7 species) were collected, and 185 hosts out of 552 (33.5%) captured in the traps were parasitized by 327 fleas belonging to 11 different species. New host records were determined for several flea species, and 5 significant associations between fleas and hosts were also found.


Subject(s)
Ectoparasitic Infestations/veterinary , Marsupialia/parasitology , Rodent Diseases/parasitology , Rodentia/parasitology , Siphonaptera/classification , Animals , Brazil/epidemiology , Ectoparasitic Infestations/epidemiology , Ectoparasitic Infestations/parasitology , Host-Parasite Interactions , Prevalence , Rodent Diseases/epidemiology
20.
Mem Inst Oswaldo Cruz ; 97(7): 959-63, 2002 Oct.
Article in English | MEDLINE | ID: mdl-12471421

ABSTRACT

A study of the associations between three species of rodents in the Atlantic forest and their parasitic arthropods was undertaken at the Juréia-Itatins Ecological Station, located in the State of São Paulo, Southeastern Brazil, from March 1989 to February 1990. Individuals of three species, Oryzomys russatus, Proechimys iheringi and Nectomys squamipes were captured and examined for ectoparasites. Eleven species of parasitic arthropods were found, including four species of insects and seven of Acari. Parasitism intensity, phenology, and rainfall were positively correlated with the abundance of the ectoparasites and their hosts. The most abundant host was O. russatus (Muridae: Sigmodontinae), and the most common parasite on it was the laelapid mite Gigantolaelaps oudemansi. The cuterebrid Metacuterebra apicalis caused myiasis in O. russatus. A mutualistic association between the staphylinid beetle Amblyopinus sp. and its host P. iheringi (Echimyidae) was observed. The few N. squamipes captured had small numbers of ectoparasites.


Subject(s)
Animals, Wild/parasitology , Arthropods/classification , Ectoparasitic Infestations/veterinary , Host-Parasite Interactions , Rodent Diseases/epidemiology , Rodentia/parasitology , Analysis of Variance , Animals , Brazil/epidemiology , Ectoparasitic Infestations/epidemiology , Ectoparasitic Infestations/parasitology , Population Density , Prevalence , Rodent Diseases/parasitology , Seasons
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