| [on siphonaptera from rodents of formosa county, goiás state (author's transl)]. | polygenis bohlsi jordani (costa lima, 1937) (siphonaptera) is for the first time recorded as ectoparasite on wild rodents captured in the "cerrado" area of central brazil. seven out of nine rodents collected were found bearing p. b. jordani. the most common species found infested with the flea were: zygodontomys lasiurus, oryzomys eliurus, calomys callosus and nectomys squamipes. | 1979 | 542652 |
| parasitological and ecological aspects of schistosomiasis mansoni in the valley of the paraíba do sul river (são paulo state, brazil) i. natural infection of small mammals with schistosoma mansoni. | small mammals naturally infected with schistosoma mansoni were studied in the valley of the paraíba do sul river (são paulo state, brazil). 192 animals of 12 species were examined post mortem. cavia aperea, holochilus brasiliensis leucogaster, nectomys squamipes squamipes, oryzomys nigripes eliurus and zygodontomys brachyurus were found infected. most schistosome eggs found in the faeces were mature but no eggs were found in the faeces of c. aperea although adults were recovered. in the other in ... | 1978 | 725994 |
| natural infection of wild rodents by schistosoma mansoni. parasitological aspects. | the evaluation of the role of rodents as natural hosts of schistosoma mansoni was studied at the pamparrão valley, sumidouro, rj, with monthly captures and examination of the animals. twenty-three nectomys squamipes and 9 akodon arviculoides with a schistosomal infection rate of 56.5% and 22.2% respectively eliminated a great majority of viable eggs. with a strain isolated from one of the naturally infected n. squamipes, we infected 75% of simpatric biomphalaria glabrata and in 100% of albino mu ... | 1992 | 1343794 |
| holochilus brasiliensis and nectomys squamipes (rodentia-cricetidae) natural hosts of schistosoma mansoni. | after several brazilian researchers, the author examines the capacity of two species of rodents cricetidae, holochilus brasiliensis and nectomys squamipes, to maintain the biological cycle of schistosoma mansoni in the field and to be parasite reservoir: (a) the role they are able to play in human endemy; (b) the methods necessary to characterize the population of schistosoma mansoni related either to man, either to rodents, either to both. | 1992 | 1343905 |
| identification and characterization of sex-linked proteins of schistosoma mansoni. | the proteins of adults worms (male and female) of two isolates (bh and rj) of schistosoma mansoni were extracted using triton x-114 phase separation. the sds-polyacrilamide gel electrophoresis profiles of the three phases (detergent, aqueous and insoluble proteins) obtained were compared after coomassie blue and silver staining, surface radioiodination and western blotting. no major differences were detected between the 2 isolates. of the 25 or more proteins which partitioned into the detergent ... | 1991 | 1842398 |
| role of nectomys squamipes squamipes in the epidemiology of schistosoma mansoni infection. | | 1973 | 4723215 |
| [studies of wild reservoirs and vectors of trypanosoma cruzi. xxvi. natural infection of the water rat, nectomys squamipes squamipes (brants, 1827) with t. cruzi]. | | 1968 | 4971320 |
| [1st finding of a rodent (nectomys squamipes) naturally infested by schistosoma mansoni, in the state of são paulo (brazil)]. | | 1969 | 5361753 |
| maritremopsis mariettavogeae sp. n. (trematoda, microphallidae) and amphimerus lancea (diesing, 1850) (trematoda, opisthorchiidae) parasites of nectomys squamipes (rodentia) in brazil. | | 1981 | 6757646 |
| mammalian wildlife diseases as hazards to man and livestock in an area of the llanos orientales of colombia. | development of the llanos orientales of colombia, and access to underdeveloped areas in the llanos, may create disease hazards to man and domestic animals or introduce exotic pathogens, creating reservoirs of infection for domestic animals and acting as limiting factors on the native wild species. a survey of wild animals common to the llanos revealed a number of parasites indigenous to the area. a total total of 59 mammalian species, representing eight orders were examined. haematozoa were repr ... | 1981 | 6788961 |
| leptospirosis in wildlife in brazil: isolation of serovars canicola, pyrogenes and grippotyphosa. | the isolation of serovar canicola from the norway rat (rattus norvegicus), shows that it is a reservoir of canicola and is therefore significant from an epidemiological point of view. the isolation of pyrogenes and grippotyphosa from a water rat, nectomys squamipes is also described. | 1980 | 7461916 |
| host-induced morphological changes of schistosoma mansoni sambon, 1907 male worms. | in order to evaluate the permissiveness of nectomys squamipes to schistosoma mansoni and the influence of the albino mice on the morphological aspects of adult worms derived from a population isolated from n. squamipes, the morphology of adult s. mansoni sambon, 1907 male worms was studied using a digital image analyser (mop videoplan) and light microscopy. their sources were as follows: (1) recovered from the wild rodent n. squamipes brants naturally infected from sumidouro, rj, brazil; (2) rec ... | 1994 | 7476225 |
| evaluation of the resistance to schistosoma mansoni infection in nectomys squamipes (rodentia: cricetidae), a natural host of infection in brazil. | the development of resistance in three stages throughout an active infection (pre-ovular, acute and initial chronic stages) was studied, comparing the total number of adult worms recovered from the reinfected group and the control groups. it was shown that nectomys squamipes was unable to develop resistance in the tested conditions and, on the other hand, reinfection in the pre-ovular period of the parasite led the rodent to present the phenomenonacilitation, with reduction of natural resistance ... | 1994 | 7855481 |
| schistosoma mansoni sambon, 1907: comparative morphological studies of some brazilian strains. | the morphology of schistosoma mansoni adult male worms from three strains which have been maintained in albino mice for several generations, was compared to a strain that has been isolated from the natural host nectomys squamipes (rodentia:muridae) captured in sumidouro (rio de janeiro state) and have been maintained in the same sylvatic rodent under laboratory conditions. total length of specimens, distance between suckers, the number of testes and extention of testes grouping were the taxonomi ... | 1995 | 8729755 |
| giardia survey in live-trapped small domestic and wild mammals in four regions in the southwest region of the state of são paulo, brazil. | for the first time, a survey on giardia in live-trapped small domestic and wild mammals was performed in four regions of state of the são paulo, brazil, with special attention to the parasitism of rattus rattus rattus by giardia. this species was found infected in all studied sites: botucatu (15.4%), conchas (28.5%), itaporanga (38.7%) and são roque (100%). two new hosts and their frequency of infection were described for giardia in nectomys squamipes, an aquatic rodent and in bolomys lasiurus, ... | 1995 | 8731362 |
| breeding of the water rat (nectomys squamipes) in the laboratory. | the water rat, nectomys squamipes, is reported as a natural host of schistosoma mansoni in brazil. this paper presents some reproductive, growth and developmental data, and laboratory management of a breeding programme for n. squamipes. the colony was derived from animals captured at sumidouro, rio de janeiro state. the animals' diploid number was 56, conception rate was 66.7% and gestation period was 30 days. litter size ranged from 1 to 6, with a mean of 4.1 (sd +/- 1.2) and a mode of 4 and 5. ... | 1996 | 8938625 |
| morphological study of adult male worms of schistosoma mansoni sambon, 1907 by scanning electron microscopy. | tubercles, spines and sensory receptors are the most studied structures of adult male worms of schistosoma mansoni isolated in other countries. the purpose of this investigation was to properly define these structures in brazilian worms. specimens 7-8 weeks after infection were recovered from albino sw mice and from a wild rodent (nectomys squamipes) and processed for scanning electron microscopy studies. photomicrographs of the anterior region with the aspects related to the outer and inner reg ... | 1997 | 9566233 |
| reevaluation of physaloptera bispiculata (nematoda: spiruroidaea) by light and scanning electron microscopy. | this study was undertaken to clarify several aspects of morphological and taxonomic characters of physaloptera bispiculata vaz and pereira, 1935, a parasite of the water rat, nectomys squamipes. the cephalic structures (including lips, papillae, teeth, amphids, and porous areas) and details of the posterior end of male and female adult worms were examined by scanning electron microscopy, leading to the addition of new taxonomic characters for this species. we consider p. bispiculata a valid spec ... | 1998 | 9645861 |
| amphimerus bragai n. sp. (digenea: opisthorchiidae), a parasite of the rodent nectomys squamipes (cricetidae) from minas gerais, brazil. | amphimerus bragai n.sp. (digenea, opisthorchiidae) from the bile ducts of a rodent from the state of minas gerais, brazil, nectomys squamipes (cricetidae), is described. the new species as studied by both light and scanning electron microscopy. a table is presented comparing the measurements of the new species with those of a. lancea (diesing, 1850) and a. vallecaucensis thatcher; 1970, parasites of dolphins and marsupials, respectively. the new species is similar in size and body form to a. val ... | 1998 | 9698889 |
| schistosoma mansoni sambon, 1907: morphometric differences between adult worms from sympatric rodent and human isolates. | a computer software for image analysis (image pro plus, media cybernetics) was utilized in male and females adult worms, aiming the morphological characterization of schistosoma mansoni samples isolated from a slyvatic rodent, nectomys squamipes, and humans in sumidouro, rio de janeiro, brazil and recovered from mus musculus c3h/he. the following characters for males's testicular lobes were analyzed: number, area, density, larger and smaller diameter, longer and shorter axis and perimeter and ex ... | 1998 | 9921377 |
| the parasitism of schistosoma mansoni (digenea-trematoda) in a naturally infected population of water rats, nectomys squamipes (rodentia-sigmodontinae) in brazil. | schistosomiasis is a health problem in brazil and the role of rodents in maintaining the schistosome life-cycle requires further clarification. the influence of schistosoma mansoni on a population of nectomys squamipes was studied by capture-recapture (1st phase, from june 1991 to november 1995) and removal (2nd phase, from april 1997 to march 1999) studies at sumidouro, rio de janeiro, brazil. during both phases coproscopic examinations were performed. at the 2nd phase the rodents were perfused ... | 2000 | 10874720 |
| identification of microsatellite loci in the water-rat nectomys squamipes (rodentia, sigmodontinae). | | 2000 | 11123638 |
| changes on schistosoma mansoni (digenea: schistosomatidae) worm load in nectomys squamipes (rodentia: sigmodontinae) concurrently infected with echinostoma paraensei (digenea: echinostomatidae). | the water rat, nectomys squamipes, closely involved in schistosomiasis transmission in brazil, has been found naturally infected simultaneously by schistosoma mansoni and echinostoma paraensei. laboratory experiments were conducted to verify parasitic interaction in concurrent infection. it was replicated four times with a total of 42 water rats and essayed two times with 90 mice pre-infected with e. paraensei. rodents were divided into three groups in each replication. a wild strain recently is ... | 2001 | 11586449 |
| description of the adult worms of a new brazilian isolate of echinostoma paraensei (platyhelminthes:digenea) from its natural vertebrate host nectomys squamipes by light and scanning electron microscopy and molecular analysis. | echinostoma paraensei lie and basch, 1967 (echinostomatidae:platyhelminthes), a 37 collar spine echinostome of the "revolutum group", has been used extensively as a model organism to study the interactions of digenetic trematodes with both their snail and vertebrate hosts. this worm was first isolated from the snail biomphalaria glabrata from belo horizonte (bh isolate), minas gerais state, brazil, by lie and basch [j parasitol (1967) 53:1192-1199]. the natural definitive host for the bh isolate ... | 2001 | 11688891 |
| biological aspects of a new isolate of echinostoma paraensei (trematoda: echinostomatidae): susceptibility of sympatric snails and the natural vertebrate host. | a new isolate of echinostoma paraensei (lie & basch, 1967) was obtained from a natural vertebrate host, the water rat nectomys squamipes. relationships with sympatric snails, biomphalaria glabrata; physa marmorata and lymnaea columella, as well as allopatric snails and the definitive hosts n. squamipes, mus musculus, rattus norvegicus, mesocricetus auratus and birds were investigated. e. paraensei developed in all sympatric snail species following exposure to one or five miracidia. p. marmorata ... | 2001 | 11688893 |
| cercarial chaetotaxy and sex differentiation of schistosoma mansoni deriving from humans and nectomys squamipes (muridae: sigmondontinae) in brazil. | a comparative study was made between sympatric isolates of schistosoma mansoni: one from a wild rodent (r) nectomys squamipes and another one from humans (h) isolated from a low endemic schistosomiasis transmission area in brazil. our purpose was to detect differences between them concerning chaetotaxy (number and pattern of distribution of the argentophilic papillae) of the cercariae by means of silver impregnation. no significant difference (x > 0.05) between isolates was noted. nevertheless, ... | 2002 | 11992163 |
| ecology and host specificity of laelapine mites (acari: laelapidae) of small mammals in an atlantic forest area of brazil. | mesostigmatic mites of the laelapinae berlese, 1892 (acari: laelapidae) are nidicolous arthropods that commonly occur in the fur of neotropical small mammmals. in this 2-yr study, the laelapine acarofauna associated with the small mammal community in an area of atlantic forest on ilha grande, rio de janeiro state, was examined, including observations on patterns of host specificity, mite dispersal, ecology, and food habits. a total of 1,347 laelapines was sampled from the pelage of 6 species of ... | 2002 | 12053977 |
| experimental evidence and ecological perspectives for the adaptation of schistosoma mansoni sambon, 1907 (digenea: schistosomatidae) to a wild host, the water-rat, nectomys squamipes brants, 1827 (rodentia: sigmodontinae). | due to the semi aquatic habits and the overlap of the geographical distribution of the water-rat, nectomys spp., with schistosomiasis endemic areas, these wild rodents are very likely to acquire schistosoma mansoni infection in their daily activities. the role of the water-rat in the s. mansoni cycle would be substantiated if one could prove that these rodents acquire the parasite during their own activity time, a completely independent time schedule of human activities. to pursue this goal, we ... | 2002 | 12426586 |
| natural schistosoma mansoni infection in nectomys squamipes: histopathological and morphometric analysis in comparison to experimentally infected n. squamipes and c3h/he mice. | histopathologic and morphometric (area, perimeter, major and minor diameters) analysis of hepatic granulomas isolated from twelve naturally infected nectomys squamipes were compared to four experimentally infected ones and six c3h/he mice. liver paraffin sections were stained for cells and extracellular matrix. both groups of n. squamipes presented peculiar granulomas consisting predominantly of large macrophages, full of schistosome pigment, characterizing an exudative-macrophage granuloma type ... | 2002 | 12426608 |
| parasitic arthropods of some wild rodents from juréia-itatins ecological station, state of são paulo, brazil. | 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 ac ... | 2002 | 12471421 |
| new records and laboratory-rearing data for ixodes schulzei (acari: ixodidae) in brazil. | ixodes schulzei aragão and fonseca was described from brazil in 1951 based on female ticks collected on wild rats from the states of rio de janeiro and santa catarina. since that time, there have been no additional reports of i. schulzei in the literature. we report two new records of i. schulzei: a female collected on the water rat nectomys squamipes (brants) from minas gerais state, and another female from this same host species from são paulo state. this last specimen was engorged and oviposi ... | 2003 | 12597665 |
| nectomys squamipes microsatellites and homologous loci in sigmodontine rodents. | three monomorphic and four highly polymorphic microsatellites of nectomys squamipes were isolated and characterised in a sample of 141 specimens from eight different brazilian localities. these seven microsatellites and four others previously described in this species were tested in seven other nonfocus sigmodontine species. at least three loci were successfully amplified in every species, but none was amplified in all species. all sequenced products in nonfocus species showed (gt)(n) motifs as ... | 2003 | 12721229 |
| cuticular architecture of hassalstrongylus epsilon (nematoda: trichostrongyloidea). | hassalstrongylus epsilon is a small nematode, whose adult forms are found among the intestinal microvilli of the water rat nectomys squamipes, brants 1827 (rodentia: muridae). the external appearance of the cuticle, which presents transversal striations and longitudinal ridges, is described using scanning electron microscopy. transmission electron microscopy of thin sections and replicas of quick-frozen, freeze-fractured, deep-etched and rotatory shadowed samples showed the presence in the cutic ... | 2003 | 12884020 |
| reproductive system abnormalities in schistosoma mansoni adult worms isolated from nectomys squamipes (muridae: sigmodontinae): brightfield and confocal laser scanning microscopy analysis. | schistosoma mansoni adult worms with genital anomalies isolated from nectomys squamipes (muridae: sigmodontinae) were studied by confocal laser scanning microscopy under the reflected mode. one male without testicular lobes (testicular agenesia/anorchism) and two females, one with an atrophied ovary and another with 17 uterine eggs, were identified. the absence of testicular lobes occurred in a worm presenting otherwise normal male adult characteristics: tegument, tubercles and a gynaecophoric c ... | 2003 | 12886415 |
| host-ectoparasite specificity in a small mammal community in an area of atlantic rain forest (ilha grande, state of rio de janeiro), southeastern brazil. | the analyses of the ectoparasite species associated with a small mammal community on ilha grande, a coastal island in southern of the state of rio de janeiro, brazil, evaluated the level of host-ectoparasite specificity. was used the jaccard index for qualitative data to analyse the similarity. the lowest value of similarity occurred between proechimys iheringi and marmosops incanus and between sciurus aestuans and nectomys squamipes (cj=0.08) and the highest between p. iheringi and oxymycterus ... | 2003 | 14595458 |
| inheritance of white head spotting in natural populations of south american water rat (nectomys squamipes rodentia: sigmodontinae). | specimens with white head spots are present at low frequency in the natural populations of south american water rat (nectomys squamipes) and absent in the sibling species nectomys rattus. we analyzed the pattern of inheritance of the phenotype using complex segregation analysis of pedigrees of a captive-bred population of n. squamipes. we found that the inheritance of the white head spot in this species can be described within the framework of the major gene recessive model with incomplete penet ... | 2004 | 14757733 |
| light and scanning electron microscopy of the miracidium of echinostoma paraensei (trematoda, echinostomatidae). | echinostoma paraensei was described 1967 by lie and basch. recently its natural definitive host, the aquatic rodent nectomys squamipes, endemic in brazil, was identified. as most of the echinostomatids, this species presents a zoonotic potential. the morphology and topography of the e. paraensei miracidium obtained from adult worms collected from the natural definitive host n. squamipes is described by light and electron microscopy. the arrangement and the dimensions of the epidermal plates are ... | 2004 | 15135866 |
| wild and synanthropic hosts of leishmania (viannia) braziliensis in the endemic cutaneous leishmaniasis locality of amaraji, pernambuco state, brazil. | evidence of leishmania infection was found in small mammals captured between 1996 and 2000 in the amaraji region, pernambuco state, brazil. the kdna polymerase chain reaction (pcr), using primers specific for subgenus l. (viannia), was positive for 43/153 water rats (nectomys squamipes), 13/81 black rats (rattus rattus), 15/103 grass mice (bolomys lasiurus), 1/14 marsh mice (holochilus scieurus), 2/50 field mice (akodon arviculoides), 2/12 woolly opossums (marmosa sp.), and 5/37 common opossums ... | 2003 | 15228244 |
| phenotypic plasticity in adult worms of schistosoma mansoni (trematoda:schistosomatidae) evidenced by brightfield and confocal laser scanning microscopies. | a comparative morphometric study was performed to identify host-induced morphological alterations in schistosoma mansoni adult worms. a wild parasite population was obtained from a naturally infected rodent (nectomys squamipes) and then recovered from laboratory infected c3h/he mice. furthermore, allopatric worm populations maintained for long-term under laboratory conditions in swiss webster mice were passed on to n. squamipes. suckers and genital system (testicular lobes, uterine egg, and egg ... | 2004 | 15250464 |
| study of hantavirus infection in captive breed colonies of wild rodents. | wild sigmondontine rodents are known to be the reservoir of several serotypes of new world hantaviruses. the mechanism of viral transmission is by aerosol inhalation of the excreta from infected rodents. considering that the captive breed colonies of various wild mammals may present a potential risk for hantaviral transmission, we examined 85 specimens of thrichomys spp. (echimyidae) and 17 speciemens of nectomys squamipes (sigmodontinae) from our colony for the presence of hantavirus infections ... | 2004 | 15558166 |
| description of adult and fourth-stage larva of litomosoides navonae n. sp. (nematoda: onchocercidae), a parasite of five species of sigmodontine rodents from northeastern argentina. | this study describes a new species of litomosoides chandler, 1931, parasitic in five different sigmodontine rodents from misiones, chaco and formosa provinces of argentina. the fourth-stage (l4) larva (male and female) is also described. l. navonae n. sp. exhibits: a bottle-shaped buccal cavity; a buccal capsule with irregularly crenate external walls; four externo-labial papillae and one ventral cephalic papilla; a well differentiated oesophagus; and sigmodontis-type spicules. the microfilaria ... | 2005 | 16315077 |
| biological variation between two brazilian geographical isolates of echinostoma paraensei. | the biological behaviour and morphometric data from two allopatric isolates of echinostoma paraensei (rio bonito - rb and sumidouro - su) collected from naturally infected nectomys squamipes from two secluded atlantic forest fragments were studied. mice that had been experimentally infected with ten encysted metacercariae of each isolate were monitored weekly in two trials to analyse worm burden and the kinetics of worm distribution along the intestine. the total number of uterine eggs, wet weig ... | 2005 | 16336719 |
| helminth communities of nectomys squamipes naturally infected by the exotic trematode schistosoma mansoni in southeastern brazil. | the water rat nectomys squamipes is endemic in brazil and found naturally infected with schistosoma mansoni. helminth communities, their prevalences, intensity of infection and abundance in n. squamipes in an endemic area of schistosomiasis in the state of rio de janeiro, brazil were studied. four species of nematodes (physaloptera bispiculata, syphacia venteli, hassalstrongylus epsilon and litomosoides chagasfilhoi) were recovered in 85.3%, two trematodes (schistosoma mansoni and echinostoma pa ... | 2006 | 17125546 |
| an ecological field study of the water-rat nectomys squamipes as a wild reservoir indicator of schistosoma mansoni transmission in an endemic area. | small mammals are found naturally infected by schistosoma mansoni, becoming a confounding factor for control programs of schistosomiasis in endemic areas. the aims of this study were: to investigate the infection rates by s. mansoni on the water-rat nectomys squamipes during four years in endemic areas of sumidouro, state of rio de janeiro, using mark-recapture technique; to compare two diagnostic methods for schistosomiasis; and to evaluate the effects of the chemotherapy in the human infected ... | 2006 | 17308757 |
| small mammal populations of an agroecosystem in the atlantic forest domain, southeastern brazil. | this study reports 2 years of the population dynamics and reproduction of a small mammal community using the removal method. the study was conducted in a rural area of the atlantic forest, in sumidouro, rio de janeiro state, brazil. the population sizes, age structure and reproduction were studied for the four most common species in the study area. the overall diversity was 1.67 and ranged between 0.8 to 1.67. the species richness was 13 considering the whole study. the most abundant species wer ... | 2007 | 17505767 |
| description of the immature stages and redescription of the female of ixodes schulzei aragão & fonseca, 1951 (acari: ixodidae), an endemic tick species of brazil. | ixodes schulzei aragão & fonseca, 1951 is a tick endemic to brazil, where nine species of ixodes latreille, 1796 are currently known to occur. larvae, nymphs and females of i. schulzei were obtained from a laboratory colony originating from an engorged female collected on a free-living water rat nectomys squamipes from the santa branca municipality, são paulo state. only female ticks were obtained from engorged nymphs. unfed immature and female adult specimens were measured and the descriptions ... | 2007 | 17896185 |
| comparison of immune responses in mice infected with different strains of strongyloides venezuelensis. | in human hosts and in murine models, the immune response to strongyloides spp. is th2 type. in addition, the profile of the host immune response follows various symptoms induced by strongyloides spp. in the present study, we demonstrated that the l2 and l49 strains of strongyloides venezuelensis obtained from bolomys lasiurus and nectomys squamipes induced significant and similar increases in eosinophil/mononuclear cell counts in the blood, peritoneal cavity fluid and bronchoalveolar lavage flui ... | 2007 | 17944744 |
| habitat associations of small mammals in southern brazil and use of regurgitated pellets of birds of prey for inventorying a local fauna. | we inventoried terrestrial small mammals in an agricultural area in southern brazil by using trapping and prey consumed by barn owls (tyto alba) and white-tailed kites (elanus leucurus). small mammals were trapped in three habitat types: corn fields, uncultivated fields ("capoeiras"), and native forest fragments. a total of 1,975 small mammal specimens were trapped, another 2,062 identified from the diet of barn owls, and 2,066 from the diet of white-tailed kites. both trapping and prey in the p ... | 2007 | 18278312 |
| biological implications of the phenotypic plasticity in the schistosoma mansoni-nectomys squamipes model. | the water-rat nectomys squamipes is mostly important non-human host in schistosomiasis mansoni transmission in brazil, due to its susceptibility, high abundance and water-contact pattern. during experimental infection of n. squamipes with schistosoma mansoni, adult worms show phenotypic plasticity. this finding led us to investigate whether biological behavior is also affected. this was assessed comparing the biological characteristics of four s. mansoni strains: be (state of belém do pará), ce ... | 2008 | 18813763 |
| serological studies in nectomys squamipes demonstrate the low sensitivity of coprological exams for the diagnosis of schistosomiasis. | the existence of wild rodents naturally infected by schistosoma mansoni is a drawback for schistosomiasis control programs. as a consequence, it is necessary to have a precise diagnosis of s. mansoni infection in wild rodents (water rats; nectomys squamipes), the species seemingly involved in the transmission of schistosomiasis at sumindouro, rio de janeiro, brazil. a total of 78 specimens of n. squamipes was captured in an endemic area at vale do pamparrão and porteira verde, sumidouro, brazil; ... | 2009 | 18983203 |
| do schistosomes grow old? a confocal laser scanning microscopy study. | infected hosts progressively decrease egg output during the chronic phase of schistosoma mansoni infection. ageing may be a factor that results in a progressive decrease in the ability to reproduce. this study was performed to gain insight into the effects of ageing on adult schistosomes, using confocal laser scanning microscopy. adult worms were recovered from experimentally infected nectomys squamipes (water rat). viable eggs were voided in the faeces for 65 weeks and, thereafter, only unviabl ... | 2010 | 19941681 |
| redescription of syphacia venteli travassos 1937 (nematoda: oxyuridae) from nectomys squamipes in argentina and brazil and description of a new species of syphacia from melanomys caliginosus in colombia. | syphacia venteli travassos, mem inst oswaldo cruz 32:607-613, 1937 is redescribed on the basis of specimens recovered from the type host, nectomys squamipes (brants 1827), from brazil and argentina. specimens determined by quentin (bull mus natl hist nat 2:909-925, 1969) as s. venteli from melanomys caliginosus (tomes 1860) in colombia were re-studied and assigned to a new species. in both species, structures such as the shape of the cephalic plate, details and distribution of the submedian papi ... | 2010 | 20169363 |
| the first description of eggs in the male reproductive system of physaloptera bispiculata (nematoda: spiruroidaea). | physaloptera bispiculata (nematoda: spiruroidaea) is a parasite of nectomys squamipes (rodentia: cricetidae), a water rat that only occurs in brazil. naturally infected rodents were captured in the municipality of rio bonito, rio de janeiro, brazil. adult p. bispiculata worms were collected, prepared and analysed by light and scanning electron microscopy. under scanning electron microscopy, several eggs were seen glued by cement to the cloacal aperture. light microscopy revealed that some male w ... | 2010 | 20653989 |
| evaluation of immunological, parasitological and molecular methods for the diagnosis of schistosoma mansoni infection before and after chemotherapy treatment with praziquantel in experimentally infected nectomys squamipes. | in low endemicity areas of schistosomiasis, the recommended diagnostic method of coprological examination results in an underestimation of infection cases. alternative diagnostic methods have been developed, such as immunodiagnostic and molecular techniques. in this study we evaluated three methods used in the diagnosis of schistosoma mansoni infection: parasitological (kato-katz), immunological (elisa) and molecular (real time pcr), and also investigated the sensitivity of each technique in the ... | 2011 | 21458922 |
| Life-cycle and host preference of Amblyomma ovale (Acari: Ixodidae) under laboratory conditions. | This study evaluated for the first time the life cycle of Amblyomma ovale in the laboratory. For this purpose, larvae and nymphs were exposed to Gallus gallus (chickens), Cavia porcellus (guinea pigs), Rattus norvegicus (wistar rats), Oryctolagus cuniculus (domestic rabbits), Calomys callosus (vesper mouse), and Didelphis albiventris (white-eared opossum). Nymphs were also exposed to Nectomys squamipes (South American water rat). Adult ticks were fed on dogs. The life-cycle of A. ovale in labora ... | 2011 | 22113779 |
| [litomosoides, parasites of rodents; taxonomic consequences]. | a redescription of the type specimens of the three following species is given: l carinii (travassos, 1919) from sciurus sp. in brazil. l, sigmodontis chandler, 1931 from sigmodon hispidus and l. scotti forrester et kinsella. 1977 from oryzomys palustris in north america. a description of two brazilian species is also given: l. galizai n. sp. from (ecomys trinitatus tapajinus and l. kohnae n. sp. from nectomys squamipes. the conclusions are: the type species of the genus litomosoides: l. sigmodon ... | 2010 | 2817694 |
| infectiousness of sylvatic and synanthropic small rodents implicates a multi-host reservoir of leishmania (viannia) braziliensis. | the possibility that a multi-host wildlife reservoir is responsible for maintaining transmission of leishmania (viannia) braziliensis causing human cutaneous and mucocutaneous leishmaniasis is tested by comparative analysis of infection progression and infectiousness to sandflies in rodent host species previously shown to have high natural infection prevalences in both sylvatic or/and peridomestic habitats in close proximity to humans in northeast brazil. | 2015 | 26448187 |
| zoonotic bartonella species in wild rodents in the state of mato grosso do sul, brazil. | several rodent-associated bartonella species cause disease in humans but little is known about their epidemiology in brazil. the presence of bartonella spp. in wild rodents captured in two municipalities of the mato grosso do sul state was assessed by polymerase chain reaction (pcr). fragments of heart tissue from 42 wild rodents were tested using primers targeting the bartonella 16s-23s intergenic transcribed spacer (its) region and citrate synthase glta gene. the wild rodents were identified b ... | 2016 | 26344604 |
| small mammals as hosts of leishmania spp. in a highly endemic area for zoonotic leishmaniasis in north-eastern brazil. | leishmania parasites cause leishmaniasis in humans and animals worldwide. these parasites are transmitted by phlebotomine sand flies, which become infected upon feeding on an infected mammalian host. we assessed the occurrence of leishmania infection in small mammals in an area of cutaneous and visceral leishmaniasis endemicity. | 2013 | 23868744 |
| natural schistosoma mansoni infection in the wild reservoir nectomys squamipes leads to excessive lipid droplet accumulation in hepatocytes in the absence of liver functional impairment. | schistosomiasis is a neglected tropical disease of a significant public health impact. the water rat nectomys squamipes is one of the most important non-human hosts in the schistosomiasis mansoni transmission in brazil, being considered a wild reservoir. cellular mechanisms that contribute to the physiological adaptation of this rodent to the schistosoma mansoni parasite are poorly understood. here we identified, for the first time, that a hepatic steatosis, a condition characterized by excessiv ... | 2016 | 27880808 |
| biochemical and histological changes in liver of nectomys squamipes naturally infected by schistosoma mansoni. | the south american water rat nectomys squamipes is a wild mammal reservoir of schistosoma mansoni in brazil. in the present study, wild rodents were collected in the field and categorized into two groups: infected and uninfected by s. mansoni. blood was collected to analyze changes in the serum glucose level (mg/dl) and liver fragments were used to determine the hepatic glycogen content (mg of glucose/g tissue). the histological examination showed inflammatory granulomatous lesions in different ... | 2014 | 24473876 |
| susceptibility of a brazilian wild rodent isolate of schistosoma mansoni to praziquantel in mice. | the therapeutic effects of praziquantel (pzq) against a schistosoma mansoni isolate derived from nectomys squamipes (isolate r) and a susceptible isolate (bh) were analyzed in swiss mice by fecal egg counting, adult worm reduction and oogram pattern. infected mice were orally administrated with 62.5mg/kg (group 1), 125mg/kg (group 2), 250mg/kg (group 3) and 500mg/kg (group 4), each dose divided over 3 days (49, 50 and 51 days after infection). the data were analyzed using one-way analysis of var ... | 2012 | 22343042 |
| new morphological data of litomosoides chagasfilhoi (nematoda: filarioidea) parasitizing nectomys squamipes in rio de janeiro, brazil. | litomosoides chagasfilhoi, originally described by moraes neto, lanfredi & de souza (1997) parasitizing the abdominal cavity of the wild rodent, akodon cursor (winge, 1887), was found in the abdominal cavity of nectomys squamipes (brants, 1827), from the municipality of rio bonito, rio de janeiro state, brazil. this study led to addition of new morphological data and a new geographical distribution for this filarioid in brazil. several characters were detailed and emended to previous records of ... | 2016 | 27925058 |
| noteworthy records of ixodes schulzei (acari: ixodidae) on rodents from the state of parana, southern brazil. | ixodes schulzei aragão & fonseca is an endemic tick to brazil and has already been reported in the northern (state of rondonia), southeastern (states of minas gerais, rio de janeiro and sao paulo) and southern (state of santa catarina) regions, always found in association with the water rat nectomys squamipes (brandt). this communication records the first occurrence of this tick species in the state of parana, southern region of brazil, and it constitutes its first report on akodon montensis (th ... | 2013 | 24252964 |
| differences in richness and composition of gastrointestinal parasites of small rodents (cricetidae, rodentia) in a continental and insular area of the atlantic forest in santa catarina state, brazil. | the first and only study on gastrointestinal parasites of wild rodents in the island of santa catarina was done in 1987. the aim of this study was to identify intestinal parasites from wild rodents in santo amaro da imperatriz and santa catariana island, and to compare the richness and composition of the gastrointestinal parasite community of both areas. rodents were captured with live traps, and feces were screened using the sedimentation method and optical microscopy. the following species of ... | 2012 | 22990827 |
| on the origin and evolution of the extant system of b chromosomes in oryzomyini radiation (rodentia, sigmodontinae). | heterogeneous supernumerary chromosomes (bs) are recognized in the oryzomyines holochilus brasiliensis, nectomys rattus, n. squamipes, oligoryzomys flavescens and sooretamys angouya, representing about 10% of all known b-containing rodent species. they provide an outstanding model for understanding the origin, evolution and diversity of bs in a phylogenetic context. therefore, whole chromosome-specific probes were generated from flow-sorted holochilus brasiliensis (hbr) autosomes 11 and 25+26 an ... | 2015 | 26305702 |
| spotted fever group rickettsia in small rodents from areas of low endemicity for brazilian spotted fever in the eastern region of minas gerais state, brazil. | we investigated the humoral immune response against different species of rickettsia in serum samples from small rodents collected in two areas of a silent focus for brazilian spotted fever in the eastern region of minas gerais state, brazil. sera samples were analyzed by indirect immunofluorescence assay using antigens from rickettsia species of the spotted fever, ancestral, and transition groups. titers ≥ 1:64 were considered positive. in santa cruz do escalvado, 94% (30 of 32) of the samples c ... | 2013 | 23509125 |
| the genus guerrerostrongylus (nematoda: heligmonellidae) in cricetid rodents from the atlantic rain forest of misiones, argentina: emended description of guerrerostrongylus zetta (travassos, 1937) and description of a new species. | two species of guerrerostrongylus sutton and durette-desset, 1991, are reported in cricetid rodents from the atlantic rain forest of misiones, argentina. guerrerostrongylus zetta (travassos, 1937) is redescribed on the basis of material collected from oligoryzomys nigripes from argentina and material loaned by chioc from brazil. it is characterized by a synlophe with about 40-45 (35-48) well-developed cuticular ridges, caudal bursa with long rays 6 and dorsal ray divided at mid-length, and well- ... | 2012 | 22494032 |
| spatial use of rodents (rodentia: mammalia) host body surface by ectoparasites. | we studied the ectoparasite and the amblyopinini beetle fauna associated with four small mammal species of the atlantic rainforest of ilha grande, an island located off the southern rio de janeiro state coast, southeastern brazil, analyzing to what extent the parasites were specific to each region of the host body. during the study, a total of 90 individual rodents were captured: 61 proechimys iheringi thomas, 1911 (echymyidae), 22 sciurus aestuans (thomas, 1901) (sciuridae), 4 oxymycterus sp. ( ... | 2002 | 12530177 |
| description of the helminth communities of sympatric rodents (muroidea: cricetidae) from the atlantic forest in northeastern argentina. | taxonomic and ecological aspects of the helminths found in the assemblage of sigmodontine rodents (cricetidae-muroidea) of the atlantic forest in argentina are studied in this paper. the following species akodon montensis, brucepattersonius sp. and thaptomys nigrita (tribe akodontini), as well as, euryoryzomys russatus, nectomys squamipes, oligoryzomys nigripes, and sooretamys angouya (tribe oryzomyini) are analyzed. a complete taxonomic list with a total of 25 species of helminths, including di ... | 2017 | 29242441 |
| life-cycle of amblyomma oblongoguttatum (acari: ixodidae) under laboratory conditions. | this study evaluated for the first time the life cycle of amblyomma oblongoguttatum in the laboratory. for this purpose, larvae and nymphs were exposed to gallus gallus (chicks), rattus norvegicus (wistar rat), calomys callosus (vesper mouse), oryctolagus cuniculus (domestic rabbit), cavia porcellus (guinea pig), and didelphis albiventris (white-eared opossum). nymphs were exposed to g. gallus, c. callosus, c. porcellus, o. cuniculus, r. norvegicus, and nectomys squamipes (water rat). adult tick ... | 2017 | 28493036 |
| histological assessment of granulomas in natural and experimental schistosoma mansoni infections using whole slide imaging. | the pathology of schistosomiasis mansoni, a neglected tropical disease of great clinical and socioeconomic importance, results from the parasite eggs that become trapped in host tissues, particularly in the liver and intestines. continuous antigenic stimulation from these eggs leads to recruitment of inflammatory cells to the sites of infection with formation of periovular granulomas. these complex structures have variable size and composition and are the most striking histopathological feature ... | 2017 | 28902908 |
| nectomys squamipes (rodentia: cricetidae) as an experimental model for schistosomiasis mansoni. | twenty specimens of nectomys squamipes born in captivity, were infected with 500 cercariae by the transcutaneous route. coprologic examinations were carried out from the 5th to 23rd week after infection. on the 7th, 8th, 12th, 16th, and 23rd weeks the animals were sacrificed and perfused. the oogram was performed in segments of the small intestine (proximal, medial and distal portions) and the large intestine. the average pre-patent period was of 42 days. the average number of eggs varied from 3 ... | 1992 | 1343795 |
| investigation of bartonella spp. in brazilian mammals with emphasis on rodents and bats from the atlantic forest. | the bartonella species are zoonotic agents that infect mammals and are transmitted by arthropod vectors. approximately 18 distinct genotypes cause diseases in humans, and may be spread by both domestic and wild animals. in brazil, bartonella genotypes have been identified in several species of wild mammals, and in the present study, we analyzed samples from non-human primates (marmosets), marsupials, rodents, and bats, and compared them with the genotypes described in mammals from brazil, to exa ... | 2020 | 32904298 |
| helminth communities of sigmonontine rodents in cocoa agroforestry systems in brazil. | agroforestry is an alternative kind of land use where the native vegetation is surrounded or intercalated by crops of economic interest. this system may maintain species richness by promoting the habitat heterogeneity or serving as ecological corridors. the aim of this study was to describe the gastrointestinal helminth fauna and to analyse the parasitological parameters of the helminth communities of six sigmodontine rodents in a cocoa agroforestry system in the municipality of ilhéus, state of ... | 2020 | 32274328 |
| historical connections among river basins and climatic changes explain the biogeographic history of a water rat. | the water rat nectomys squamipes (cricetidae: sigmodontinae) is a semiaquatic rodent from eastern south america that shows shallow genetic structure across space, according to some studies. we tested the influence of hydrography and climatic changes on the genetic and phylogeographic structure of this semiaquatic small mammal. | 2018 | 30065889 |
| is arachidonic acid an endoschistosomicide? | schistosoma mansoni and schistosoma haematobium are intravascular, parasitic flatworms that infect >250 million people in 70 developing countries, yet not all people of the same community and household are afflicted. regarding laboratory rodents, mice but not rats are susceptible to infection with s. mansoni and hamsters but not mice are entirely permissive to infection with s. haematobium. a recent brazilian publication has demonstrated that resistance of the water-rat, nectomys squamipes to s. ... | 2018 | 30034878 |
| morphological effects on helminth parasites caused by herbicide under experimental conditions. | helminth parasites have been studied as potential accumulators for different pollutants. echinostoma paraensei is a foodborne trematode whose vertebrate host, the rodent nectomys squamipes, is naturally exposed to environmental pesticides. however, little information exists regarding the pesticide's effects on helminths. this study investigated the morphological effects on the trematode, e. paraensei, after experimental roundup® herbicide exposure, in concentrations below those recommended for a ... | 2018 | 29641790 |