natural schistosoma mansoni infection in arvicanthis niloticus in ismailia, a survey for zoonotic helminthic infection in rodents schistosoma mansoni eggs were detected in the large intestine and liver of arvicanthis niloticus.19902121849
leptospirosis in the melut district--upper nile province (south sudan)--an overview.the authors examined 195 domestic animals for leptospirosis serologically in sudan (170 cattle, 7 sheep and 18 goats) and 771 wild animals (36 species) with 13 serovars from 13 serogroups. 54% of domestic animals namely, 108 cattle and 1 sheep were positive in titer levels of 1:400 and higher. cattle sera with the serovars of the serogroup icterohaemorrhagiae were 2.4% positive with cynopteri 2.4%, autumnalis 3.5%, australis 1.2%, pomona 2.9%, grippotyphosa 2.9%, hebdonadis 17.1%, bataviae 9.4% ...19892599388
cutaneous leishmaniasis caused by leishmania major in baringo district, kenya.leishmania major was isolated from lesions of a patient suffering from cutaneous leishmaniasis in baringo district of kenya. isoenzyme mobilities of this strain were compared with those of l. major, l. donovani, l. aethiopica and l. tropica reference strains and also l. major from a sand fly, phlebotomus duboscqi, and a rodent, arvicanthis niloticus, trapped in the same region. the patient's isolate had similar banding patterns to the l. major reference strain and also the rodent and the sand fl ...19873445343
[demonstration of the pathogenic capacity for man of the leishmania strain isolated in an arvicanthis niloticus in piroundary (senegal). voluntary inoculation, auto-observation]. 19664955898
[importance of systematic cultures and subcultures in research on natural viral reservoirs in cutaneous leishmaniasis. apropos of the isolation of 5 strains of leishmania in arvicanthis niloticus]. 19674969779
leishmaniasis in the sudan republic. 25. experimental visceral leishmaniasis in the nile grass rat, arvicanthis niloticus niloticus dollman. 19665909671
[study of the receptivity of arvicanthis niloticus (desmaret 1822) to various pathogenic agents]. 19694241428
studies on schistosoma bovis in ethiopia.schistosoma bovis occurs in at least seven of the 14 rovinces of ethiopia. results of faecal and snail surveys in three foci are reported. adwa. one collection showed that nine out of 26 bulinids were infected with s. bovis. the snail host was a tetraploid form of bulinus (n = 36). the examination of 200 specimens of cattle faces revealed no s. bovis eggs, which was attributed to poor technique or light infection. gewani. the snail host was bulinus abyssinicus, which was also infected with s. ha ...1975808181
temperature and water conditions mediate the effects of day length on the breeding cycle of a sahelian rodent, arvicanthis niloticus.laboratory studies of variations in testicular activity (testicular weight and plasma testosterone concentration) were carried out on two populations of arvicanthis niloticus, a sahelian rodent that displays the particularity of being able to breed in the dry season. the animals were captured during phases of sexual activity or inactivity and were maintained in the laboratory for 50 days under humid conditions (water-rich diet, 90% atmospheric relative humidity) or dry conditions (water-deficit ...19938218633
a longitudinal survey of borrelia crocidurae prevalence in rodents and insectivores in senegal.we report results of a longitudinal survey designed to determine the importance and the dynamics of borrelia crocidurae, the spirochete responsible for tick-borne relapsing fever in west africa in rodents and insectivores in a rural area of northern senegal. a total of 954 animals were caught during bimonthly capture sessions over a two-year period. positive thick blood smears were recorded in 17.6% of the 740 rodents and 7.3% of the 55 musk shrews tested. variations of prevalence were analyzed ...19948116808
larval occurrence of hydatigera taeniaeformis batsch (1786) (cestoda: taeniidae) in the liver of wild rodents in egypt.hydatigera taeniaeformis batsch (1786) was found in the liver of six species of egyptian wild rodents. wanas et al., (1990) found the total incidence of this larval stage to be 20.0% among cestode infection. it was found in (40.9%) rattus norvegicus; (33.3%) gerbillus gerbillus; (26.8%) rattus rattus; (25.0%) mus musculus; (16.6%) acomys cahirinus; and (7.2%) arvicanthis niloticus. the cysts of hydatigera taenioformis was always occupying the marginal surfaces of both right and left lobes and so ...19938376855
sarcocystis singaporensis: studies on host specificity, pathogenicity, and potential use as a biocontrol agent of wild specificity and pathogenicity of sarcocystis singaporensis were investigated as a prerequisite to a subsequent application of the parasite as a biocontrol agent of wild rats in egypt. after inoculation of 7 snake species comprising the families elapidae, viperidae, colubridae, and boidae with sarcocysts, sporocyst development was only observed in a reticulated python. among amphibians, reptiles, and rodents that orally received various sporocyst doses in the laboratory, 2 x 10(4) sporocysts ...19968604097
[a filaria of african muridae in the wall of the colon: monanema martini n. sp].description of m. martini n. sp. (= m. nilotica el bihari et al., 1977 sensu bain et coll., 1985), a parasite of arvicanthis niloticus from mali. the natural host is arvicanthis niloticus from mali; the description is based on material from experimentally infected laboratory-bred rodents (holotype from a. niloticus; other specimens from lemniscomys striatus). like other related species the microfilariae of m. martini are said to be "skin dwelling" (in fact they are in cutaneous lymphatic vessels ...19863813428
characterization of kenyan leishmania spp. and identification of mastomys natalensis, taterillus emini and aethomys kaiseri as new hosts of leishmania major.a survey to examine rodents for leishmanias was initiated in the perkerra settlement scheme, marigat, baringo district, kenya, 789 rodents of ten different species were trapped and examined. leishmanial parasites were isolated from the spleen and liver of 17 animals of five different species: seven from tatera robusta, five from arvicanthis niloticus, two from mastomys natalensis, two from taterillus emini and one from aethomys kaiseri. these were identified as l. major by enzyme electrophoresis ...19863632097
prevalence of ife virus infection in wild rodents and birds from zaria, hundred eighty-three wild rodents and 38 wild birds trapped near zaria were screened for virus and complement fixing (cf) antibody to ife virus. virus was not isolated but cf antibody was detected in 8% cricetomys gambianus and 31% arvicanthis niloticus tested. the presence of ife virus has been documented now in three ecological zones of nigeria.19873682093
effect of tranquilizers on the total acetylcholine content and acetylcholinesterase activity in the brain tissue of arvicanthis niloticus.the effect of reserpine and meprobamate on the total acetylcholine content and acetylcholinesterase activity in the brain tissue of the kusu rat, arvicanthis niloticus, was studied. the total acetylcholine content and acetylcholinesterase activity were determined 1 hr after i.p. injection of different doses of reserpine (0.25, 0.5 and 1 mg/ml/100 g body wt) and meprobamate (6.25, 12.5 and 25 mg/ml/100 g body wt). the effect of different time intervals (1, 10, 30 min, 1, 2.5, 5, 8, 12, 24 and 48 ...19852866923
results of serological examination for leptospirosis of domestic and wild animals in the upper nile province (sudan).195 domestic and 766 wild animals were serologically examined for leptospirosis. cattle was found to be positive at titres 1 greater than or equal to 400 in 63.5%, namely 50.6% for tarassovi, 17.1% for sejroe-hebdomadis, 9.4% for bataviae, 1.2-3.5% for icterohaemorrhagiae, cynopteri, autumnalis, australis, pomona and grippotyphosa. sera from 35 animals reacted with the serovars from two or more serogroups. of 7 sheep 1 was positive for pomona and 18 goats proved to be negative. 10.2% of wild mam ...19892809189
ophthalmological study of the lesions induced by the filarial worm with dermal microfilariae, monanema martini, in its murid hosts.the filaria monanema martini with skin-dwelling microfilariae induces in its natural murid hosts lesions similar to those in human onchocerciasis. this was demonstrated by histo-pathological studies but it appeared useful to evaluate the model by a clinical investigation. an ophthalmological analysis was performed on the two species of hosts, inoculated by one, two, or multiple doses of larvae, and with infections of at least one year duration. a total of 140 eyes was examined (anterior and post ...19938293664
endogenous stages of eimeria arvicanthi infecting the field rat arvicanthis niloticus niloticus from egypt.the endogenous stages of eimeria arvicanthi were studied after experimental infection with pure strain in the rat arvicanthis n. niloticus. the prepatent period was 5 days, while the patent period extended to the 11th day p.i. two asexual generations were determined in the epithelial cells of the upper part of the colon, while the sexual one was found in the crypts of lieberkühn. schizonts of the 1st generation were found 60 hrs p.i., measuring 9 x 4 microns and contained 4-8 merozoites, however ...19902332656
the murid filaria monanema martini: a model for onchocerciasis. part i. description of lesions.a study of the anatomo-pathological lesions induced by monanema martini, a filaria with skin-dwelling microfilariae, was performed using 65 lemniscomys striatus fixed from 30 minutes to 36 months after inoculation of the infective larvae, 5 arvicanthis niloticus and 3 meriones unguiculatus fixed during the patent phase, and controls. attempts at quantification of lesions in l. striatus was made. approximately 20% of l. striatus had microfilariae in the eyeballs, and many more presented ocular le ...19911776782
studies on flea fauna in el fayoum governorate, egypt.this paper dealt with the studies of flea fauna as collected on the rodent hosts over one year. the collected rodents (499) in a descending order of abundance in the collection were rattus rattus, r. norvegicus, mus musculus, gerbillus pyramidum and arvicanthis niloticus. the collected fleas in a descending order in the collection were x. cheopis, p. irritans, n. jasciatus, c. felis, l. segnis and e. gallinacea. the total flea index reached the maximum (0.76) in may and it was zero in december a ...19921431297
[receptivity of arvicanthis niloticus to infection by schistosoma mansoni]. 1976135626
association of ticks (acari: ixodoidea) with rodent burrows in northern senegal.four species of ticks were retrieved from burrows of 64 multimammate rats, mastomys erythroleucus (temminck), 55-gerbils, taterillus gracilis (thomas) or t. pygargus (cuvier), 13 nile rats, arvicanthis niloticus (demarest), and five geoffroy's ground squirrels, xerus erythropus (geoffroy) from may 1987 through august 1988 at two study sites in northern senegal. ornithodoros sonrai sautet & witkowski were recovered from 95% (74/78) of burrows near bandia and 6% (4/66) of burrows near yonofere. ei ...19938360905
sex ratio and phoretic mites of fleas (siphonaptera: pulicidae and hystrichopsyllidae) on the nile grass rat (arvicanthis niloticus) in kenya.the sex ratio of fleas and their phoretic mites associated with the nile grass rat, arvicanthis niloticus (desmarest), were studied during 14 mo in a grassland community of lake nakuru national park, kenya. females of the fleas dinopsyllus lypusus jordan & rothschild, ctenophthalmus calceatus cabirus jordan & rothschild, and xenopsylla cheopis bantorum jordan infested more grass rats and in greater numbers than did males. phoretic hypopi (hetermorphic deutonymphs) of two species of mites, psyllo ...19938433319
a comparative study of three methods of detection of borrelia crocidurae in wild rodents in a rural area in sénégal with a high incidence of tick-borne relapsing fever in humans, borrelia crocidurae was studied in the blood and brain of wild rodents (mastomys erythroleucus, arvicanthis niloticus and rattus rattus) using 3 methods: (i) direct examination of thick blood films; (ii) intraperitoneal inoculation of blood into white mice; (iii) intraperitoneal inoculation of homogenized cerebral tissue into white mice. of the 82 rodents examined, the proportion of infected animals was res ...19947570827
animal reservoirs of leishmaniasis in marigat, baringo district, kenya.a total of 1128 rodents belonging to seven genera were examined for leishmanial parasites over a period of sixteen months. parasites were isolated from 36 (12.5%) tatera robusta, 3 (0.5%) arvicanthis niloticus, and 2 (0.8%) mastomys natalensis. all isolates were characterised by isoenzyme analysis using nine enzymes. the enzymes examined were: malate dehydrogenase (mdh), phosphoglucomutase (pgm), glucose phosphate isomerase (gpi), isocitrate dehydrogenase (icd), nucleoside hydrolase (nh), glucos ...19968625862
the potential role of rodents in the enzootic cycle of rift valley fever virus in senegal.wild rodents (214) of fourteen species were trapped at seven sites in senegal. arvicanthis niloticus and mastomys erythroleucus were among the most frequently collected species (77.2% of total capture). all rodents were examined for the presence of anti-rift valley fever virus (rvfv) antibody; the prevalence over all sampled species was 3.8%, varying widely with respect to species and location. four of 14 species of rodents were found to have anti-rvfv antibodies: rattus rattus (one positive of ...200010817634
observations on a polycephalic cestode larva from a nile rat (arvicanthis niloticus). 19883417203
effect of barbitone sodium and thiopental sodium on brain dopamine, noradrenaline, serotonin and 5-hydroxyindoleacetic acid content in arvicanthis niloticus.the quantitative estimation of total dopamine (da), noradrenaline (ne), serotonin (5-ht) and 5-hydroxyindoleacetic acid (5-hiaa) content in the whole brain tissue of normal nile grass rat, arvicanthis niloticus, gives and average of 631 +/- 12 ng da/g, 366 +/- 12 ng ne/g, 617 +/- 15 ng 5-ht/g and 431 +/- 10 ng 5-hiaa/g fresh brain tissue. the effect of barbitone sodium and thiopental sodium on the total da, ne, 5-ht and 5-hiaa content in the brain tissue of the nile grass rat, arvicanthis niloti ...19872435454
susceptibility of rodents to infection with schistosoma mansoni in richard-toll (senegal).the susceptibility of arvicanthis niloticus, mastomys huberti, mastomys erythroleucus and mus musculus was studied to assess the capacity of these rodents to transmit schistosoma mansoni. the susceptibility was determined by the percentage of adult schistosomes recovered, the number of eggs per gramme of faeces, the viability of these eggs and the capacity of the rodents to maintain the life cycle of schistosoma mansoni. the percentages of adult worms recovered were respectively 18%, 11.5%, 8.4% ...19969033908
[experimental transmission of monanema nilotica el bihari & coll., 1977, a filaria with skin-dwelling microfilaria parasitic in african murids].the value of monanema of murids as experimental models of ocular lesions due to onchocerciasis would be greatly increased if we could experiment with several host and parasite species since, in many cases, the lesions induced are more significant when the host-parasite association is poorly adapted. the life cycle of 2 isolates of monanema nilotica is completed, one from lemniscomys striatus from the central african republique and the other from arvicanthis niloticus of mali. as in m. globulosa, ...19853985535
wheel-running rhythms in arvicanthis niloticus.wheel-running behaviour of the nile grass rat, arvicanthis niloticus, was studied under a variety of lighting conditions to characterize circadian rhythms in this species. a series of lighting schedules was used to determine the nature of entrainment, the rates of reentrainment after 6-h phase shifts, and the stability of free-running rhythms in constant light (ll) and constant dark (dd). all 15 individuals showed peaks of activity around dawn and dusk, 11 were more likely to run when lights wer ...19979089754
permissiveness of two african wild rodents, mastomys huberti and arvicanthis niloticus, to schistosoma intercalatum: epidemiological consequences.the compatibility between schistosoma intercalatum (cameroon) and two wild rodents commonly found in africa. mastomys huberti (the multimammate mouse) and arvicanthis niloticus (the nile rat) was studied to determine their biological capacities to act as hosts for s. intercalatum. in both rodent species the general mean worm recovery was high (33 +/- 0.1% in m. huberti and 33.8 +/- 0.1% in a. niloticus) and worm mortality was very low from 6 to 20 weeks postinfection; parasite maturity was reach ...19979211508
[interepidemic surveillance of a cutaneous leishmaniasis focus in senegal].the cutaneous leishmaniasis is rampant in an endemo -epidemic way in the region of thiès, senegal. at the occasion of an epidemic observed between 1975 and 1978, the ecological study of the focus of keur moussa , led by dedet and al., permitted to discover, for the first time in west africa, the structure of a cutaneous leishmaniasis focus. the most important part of the present laboratory work consists in the observation of that wild anthropozoonosis due to leishmania tropica major, having as v ...19846738336
studies on the leishmaniases in the sudan. 2. clinical and parasitological studies on cutaneous the omdurman hospital for tropical diseases, sudan, from 6 october to 1 december 1986, 736 patients with cutaneous leishmaniasis (cl) were studied. the duration of the lesions varied from a few days to 4 months, usually (56%) 1-3 months. multiple lesions ranging from one to 50 (mean = 4) were present in 80% of cases. ulcerative lesions were found in 44%, nodulo-ulcerative in 31%, nodular in 31% and others, including infiltrated, fungating and warty lesions, in 5% of patients. the lower limbs ...19911661450
female prostate in arvicanthis niloticus and meriones libycus.a female prostate is reported in arvicanthis niloticus (field rat) and meriones libycus for the first time, as a normal, constant and well developed bilateral sex organ.19751237983
studies on the nematode parasites from egyptian rodents. i. spirurid nematodes.three spirurid nematode species have been collected from egyptian rodents in giza province. streptopharagus kuntzi was collected from stomach and small intestine of rattus ratus, r. norvegicus, arvicanthis niloticus and gerbillus gerbillus. protospirura muris and p. marsupialis have also been collected from a. niloticus, r. rattus and r. norvegicus but p. marsupialis was collected only from the stomach while p. muris collected from stomach and small intestine. p. marsupialis was firstly recorded ...19938308360
daily rhythms of fos expression in hypothalamic targets of the suprachiasmatic nucleus in diurnal and nocturnal rodents.little is known about the differences in the neural substrates of circadian rhythms that are responsible for the maintenance of differences between diurnal and nocturnal patterns of activity in mammals. in both groups of animals, the suprachiasmatic nucleus (scn) functions as the principal circadian pacemaker, and surprisingly, several correlates of neuronal activity in the scn show similar daily patterns in diurnal and nocturnal species. in this study, immunocytochemistry was used to monitor da ...199910447310
nocturnal and diurnal rhythms in the unstriped nile rat, arvicanthis a laboratory population of unstriped nile grass rats, arvicanthis niloticus, individuals with two distinctly different patterns of wheel-running exist. one is diurnal and the other is relatively nocturnal. in the first experiment, the authors found that these patterns are strongly influenced by parentage and by sex. specifically, offspring of two nocturnal parents were significantly more likely to express a nocturnal pattern of wheel-running than were offspring of diurnal parents, and more fe ...199910511004
observations on the current status of plague endemicity in the western usambara mountains, north-east tanzania.epidemiological investigations were executed at 6 locations in the western usambara mountains in north-east tanzania from november 1980 to may 1982. rodent, human and dog sera were checked for agglutinating plague antibodies, using the passive haemagglutination test. fraction i plague antigen was similarly tested for in rodent organ macerates. bubo aspirates and rodent organ-smears were microscopically examined for plague bacilli. a total of 257 rodents and 191 fleas were collected. rattus rattu ...19836142635
[trichosomoides nasalis biocca & aurizi, 1961 and t. spratti n. sp. (nematoda: trichinelloidea), from the nasal cavity of murids].the nematode parasite of the nasal mucosa of rodents, trichosomoides nasalis, is common in the murid arvicanthis niloticus, in senegal. the morphological study of this material allowed us to augment the original description, made with specimens recovered in italy from rattus norvegicus. this analysis shows that specimens from rattus fuscipes in australia, which had been identified to this species, represent a distinct species (smaller, with an average of five intrauterine males per female instea ...200011031758
two new species of nippostrongylinae (nematoda, trichostrongylina) parasites of cricetomys gambianus and arvicanthis niloticus (muridae) from senegal.two new nippostrongylinae (heligmosomoidea, heligmonellidae) originating from senegal are described. heligmonina bioccai n. sp., a parasite of cricetomys gambianus (cricetomyinae) found in the surroundings of dakar and neoheligmonella bai n. sp., a parasite of arvicanthis niloticus (murinae) from the province of richard toll. h. bioccai n. sp. is related to h. hybomysi (durette-desset, 1966) a parasite of hybomys univittatus from the central african republic by some characteristics of the caudal ...200212404816
patterns of body temperature, activity, and reproductive behavior in a tropical murid rodent, arvicanthis niloticus.nile grass rats (arvicanthis niloticus), are murid rodents from tropical africa that exhibit diurnal patterns of wheel-running. in the present paper we describe the temporal organization of several other behaviors in these animals, as well as daily rhythms in their body temperature. in the first experiment, we characterized rhythms of gross motor activity and core body temperature in four adult females implanted with telemetry transmitters and kept on a 12:12 light:dark (ld) cycle. in all animal ...19979226347
comparison of human and murine isolates of schistosoma mansoni from richard-toll, senegal, by isoelectric focusing.studies on human and murine isolates of schistosoma mansoni, from richard-toll, senegal, were carried out by isoelectric focusing in polyacrylamide gels. seven enzyme systems; lactate dehydrogenase (ldh), malate dehydrogenase (mdh), glucose-6-phosphate dehydrogenase (g6pd), acid phosphatase (acp), hexokinase (hk), glucose phosphate isomerase (gpi), and phosphoglucomutase (pgm), were used to compare the two isolates. all systems tested, apart from ldh, were found to be polymorphic for both isolat ...19979192707
arvicanthis niloticus desmarest, 1822, a new host for borrelia crocidurae in egypt. 196314028028
subulura saloumensis n. sp. (nematoda, subuluroidea) from four species of rodents in senegal.a new species of the genus subulura is described from 4 new rodent hosts: arvicanthis niloticus, mastomys erythroleucus, mastomys huberti, and tatera gambiana. subulura saloumensis n. sp. differs from the congeneric species by the morphology of its head. the absence of buccal lobes, the length of right and left spicules, the absence of caudal alae, and the existence of a caudal papillae with a sensorial bristle. the latter, which we observe for the first time in specimens gathered from m. hubert ...19989645859
a molecular perspective on the systematics and evolution of the genus arvicanthis (rodentia, muridae): inferences from complete cytochrome b gene sequences.systematics of the genus arvicanthis, the african unstriped grass rat, are somewhat controversial. most recent taxonomic revisions list five to six species but the definition of some of these (arvicanthis dembeensis, arvicanthis nairobae, and arvicanthis niloticus) is uncertain. the complete mitochondrial cytochrome b gene (1140 bp) was sequenced for 20 specimens from throughout the range of the genus to determine the intrageneric genetic structure, construct a molecular phylogeny, and evaluate ...19989751921
[interepidemic supervision of the leishmania focus of keur moussa (thies, senegal)].a supervision of the focus of human cutaneous leishmaniasis of keur moussa has been carried out in 1988-1989 and in 1991-1992. among the 13 species gathering the 10,144 phlebotomine sandflies trapped, two belong to genus phlebotomus, the others to genus sergentomyia. phlebotomus duboscqi, that has been found out by deded et al. in 1980 as the vector of this leishmaniasis in senegal, is the most represented species after sergentomyia schwetzi, with respectively 32.3 and 28.5% of the found during ...19989754297
calretinin is not a marker for subdivisions within the suprachiasmatic this study, we report the immunocytochemical localization of the calcium-binding protein calretinin (cal) in the suprachiasmatic nuclei (scn) of male and female rodents including rats, mice, golden hamsters, and arvicanthis niloticus. the results revealed that cal is present in different subdivisions of the scn in the different species studied and cal can, therefore, not be considered a marker for particular subdivisions within the scn. no differences were found between males and females.200010784124
fos expression within vasopressin-containing neurons in the suprachiasmatic nucleus of diurnal rodents compared to nocturnal rodents.the underlying neural causes of the differences between nocturnal and diurnal animals with respect to their patterns of rhythmicity have not yet been identified. these differences could be due to differences in some subpopulation of neurons within the suprachiasmatic nucleus (scn) or to differences in responsiveness to signals emanating from the scn. the experiments described in this article were designed to address the former hypothesis by examining fos expression within vasopressin (vp) neuron ...199910036991
distribution of ca2+-dependent protein kinase c isoforms in the suprachiasmatic nucleus of the diurnal murid rodent, arvicanthis niloticus.the suprachiasmatic nuclei (scn) contain the major 'biological clock' in mammals that controls most circadian rhythms expressed by these animals. the functional importance of protein phosphorylation and intracellular ca2+ in the mammalian circadian pacemaker is becoming increasingly apparent. here we report the immunocytochemical localization of the four ca2+-dependent protein kinase c (pkc) isoforms (alpha, betai, betaii, gamma) within the scn of the diurnal murid rodent, arvicanthis niloticus, ...19999878732
[ecology of a cutaneous leishmaniasis focus in the thies region (senegal, west africa). 5. spontaneous infection and disease reservoir role of various wild rodent species].the authors describe spontaneous infection of mastomys erythroleucus and tatera gambiana by leishmania strains typed as l. major. they argue the reservoir role to these two species and the one of arvicanthis niloticus previously found infected. the possible relations between the fluctuations of rodent populations and the incidence of the human disease are then discussed.19817296732
chromosomal phylogeny of muridae: a study of 10 genera.the karyotypes of 10 different species of the family muridae (acomys airensis, arvicanthis niloticus, hylomyscus stella, malacomys longipes, mastomys huberti, myomys daltoni, mus musculus, rattus norvegicus, thamnomys gazellae, and uranomys ruddi) are compared by different banding techniques. from a reconstruction of the presumed ancestral karyotype of the muridae the sequence of the various rearrangements leading to the present karyotypes is proposed in order to determine their phylogenetic rel ...19836617265
rodents as reservoir hosts in the transmission of schistosoma mansoni in richard-toll, senegal, west africa.more than 2000 animals belonging to six different rodent species and one insectivore species were examined for infection with schistosomes in the region of richard-toll, senegal. two murid rodents, arvicanthis niloticus and mastomys huberti, were found infected with schistosoma mansoni. prevalences were about 5% for both rodent species with a mean worm burden of about 20 worms per host. the sex-ratios of s. mansoni worms were always biased towards males. prevalences and worm burdens, although si ...200010881283
differences in the suprachiasmatic nucleus and lower subparaventricular zone of diurnal and nocturnal rodents.diurnal and nocturnal species are profoundly different in terms of the temporal organization of daily rhythms in physiology and behavior. the neural bases for these divergent patterns are at present unknown. here we examine functional differences in the suprachiasmatic nucleus (scn) and one of its primary targets in a diurnal rodent, the unstriped nile grass rat (arvicanthis niloticus) and in a nocturnal one, the laboratory rat (rattus norvegicus). grass rats and laboratory rats were housed in a ...200415219664
individual differences in wheel-running rhythms are related to temporal and spatial patterns of activation of orexin a and b cells in a diurnal rodent (arvicanthis niloticus).this study investigated the relationship between the orexins and patterns of activity in the diurnal nile grass rat, arvicanthis niloticus. some individuals of this species switch to a more nocturnal pattern when given access to a running wheel, while others continue to be most active during the day. in both day- and night-active grass rats, the percentages of orexin a (oxa) and orexin b (oxb) cells expressing fos were highest when animals were actively running in wheels. in night-active animals ...200415219665
calbindin and fos within the suprachiasmatic nucleus and the adjacent hypothalamus of arvicanthis niloticus and rattus norvegicus.the suprachiasmatic nucleus is the site of the primary circadian pacemaker in mammals. the lower sub paraventricular zone that is dorsal to and receives input from the suprachiasmatic nucleus may also play a role in the regulation of circadian rhythms. calbindin has been described in the suprachiasmatic nucleus of some mammals, and may be important in the control of endogenous rhythms. in the first study we characterized calbindin-expressing cells in the suprachiasmatic nucleus and lower sub-par ...200011029548
fos rhythms in the hypothalamus of rattus and arvicanthis that exhibit nocturnal and diurnal patterns of rhythmicity.this study compared patterns of fos expression within the suprachiasmatic nucleus (scn), the region immediately dorsal to the scn (the lower subparaventricular zone, lspv), and the supraoptic nucleus (son) of grass rats (arvicanthis niloticus) and lab rats (rattus norvegicus). among grass rats we also compared individuals exhibiting nocturnal and diurnal patterns of wheel running. in the scn of both groups of grass rats, as well as laboratory rats, fos was elevated during the light compared to t ...200111311870
the sandfly fauna in the visceral-leishmaniasis focus of gedaref, in the atbara-river area of eastern sudan.visceral leishmaniasis (vl) is an acute public-health problem in sudan. between 1997 and 2000, four, brief entomological surveys were carried out in barbar el fugarra, a village in the state of gedaref, in the atbara-river area of eastern sudan. between 1996 and 1999, 658 cases of vl occurred among the village's population of about 4000. cdc miniature light-traps set inside and outside human dwellings were used to collect a total of 12,745 sandflies, including five species of the genus phlebotom ...200212396326
the expression of fos within the suprachiasmatic nucleus of the diurnal rodent arvicanthis niloticus.rhythms in the expression of the nuclear phosphoprotein fos, have been demonstrated in the suprachiasmatic nucleus (scn) of nocturnal rodents. when rats are housed in a 12:12-h light/dark (ld) cycle the number of fos-immunoreactive (-ir) cells within the scn is higher during the day than at night [9,23]. in the two experiments reported here, fos-ir was examined in the scn of a diurnal murid rodent, arvicanthis niloticus. first, thirty-six adult male a. niloticus housed in a 12:12-h ld cycle were ...19989593811
individual differences in rhythms of behavioral sleep and its neural substrates in nile grass rats.laboratory populations of grass rats (arvicanthis niloticus) housed with a running wheel show considerable variation in patterns of locomotor activity. at the extremes are "day-active" (da) animals with a monophasic distribution of running throughout the light phase and "night-active" (na) animals exhibiting a biphasic pattern with an extended peak at the beginning of the dark phase and a brief peak shortly before lights-on. here, the authors use this intraspecific variation to explore interacti ...200516275771
effect of thiopental sodium and barbitone sodium on the total acetylcholine content and acetylcholinesterase activity in the brain tissue of arvicanthis niloticus.the total ach content and ache activity were determined 1 hr after the i.p. injection of different doses of thiopental sodium (5, 10 and 20 mg/ml/100 g body wt) and barbitone sodium (20, 40 and 80 mg/ml/100 g body wt). the effect of different time intervals (1 min, 10 min, 30 min, 1 hr, 2.5 hr, 5 hr, 8 hr, 12 hr, 24 hr and 48 hr) on the total ach content and ache activity was investigated after i.p. injection of 10 mg thiopental sodium and 40 mg barbitone sodium/ml/100 g body wt. both thiopental ...19862869896
nocturnal activity in a diurnal rodent (arvicanthis niloticus): the importance of is known that day-active nile grass rats, arvicanthis niloticus, increase the amount of activity in the night relative to that in the day when provided with running wheels. this was confirmed in the present study. animals without a wheel displayed 69.0% of their general activity in the l phase of a 12:12 h light-dark cycle; animals provided with wheels had only 48.6% of their wheel revolutions in the light. the contribution of direct (masking) responses to light to the increased nocturnality ...200414964704
long-term infection with schistosoma mansoni (gezira strain--sudan) in the nile rat (arvicanthis niloticus).the long-term infection with schistosoma mansoni (gezira strain--sudan) was studied in the nile rat (arvicanthis niloticus) to investigate the 'self cure' phenomenon. the results indicated that while a considerable number of worms and eggs were still recovered by week 28 post-infection, elimination of some of the worms occurred by week 20.19883135307
rhythms in expression of per1 protein in the amygdala and bed nucleus of the stria terminalis of the diurnal grass rat (arvicanthis niloticus).in the diurnal rodent arvicanthis niloticus (grass rats) the pattern of expression of the clock genes and their proteins in the suprachiasmatic nucleus (scn) is very similar to that seen in nocturnal rodents. rhythms in clock gene expression have been also documented in several forebrain regions outside the scn in nocturnal ratus norvegicus (lab rats). to investigate the neural basis for differences in the circadian systems of diurnal and nocturnal mammals, we examined per1 expression in the ova ...200818599213
n-methyl-d-aspartate microinjected into the suprachiasmatic nucleus mimics the phase-shifting effects of light in the diurnal nile grass rat (arvicanthis niloticus).mammals exhibit circadian rhythms in behavior generated by the suprachiasmatic nucleus (scn). exposure to light synchronizes the circadian clock to the environmental light:dark cycle through the release of glutamate into the scn. in nocturnal animals such as syrian hamsters, direct application of nmda to the scn results in phase shifts similar to those produced by exposure to light. this study was designed to determine if light phase shifts the circadian pacemaker of diurnal nile grass rats (arv ...200212270504
arginine vasopressin and vasoactive intestinal polypeptide fibers make appositions with gonadotropin-releasing hormone and estrogen receptor cells in the diurnal rodent arvicanthis niloticus.diurnal and nocturnal animals differ with respect to the timing of a host of behavioral and physiological events including those associated with estrus, but the neural bases of these differences have not been elucidated. we investigated this issue by examining the distribution of cells containing gonadotropin-releasing hormone (gnrh) as well as estrogen receptors (ers) in relation to fibers containing peptides present in the suprachiasmatic nucleus (scn) in a diurnal animal, arvicanthis niloticu ...200515936731
a daily rhythm in mating behavior in a diurnal murid rodent arvicanthis niloticus.the time of day at which mating occurs is dramatically different in diurnal compared to nocturnal rodents. we used a diurnal murid rodent, arvicanthis niloticus, to determine if inverted rhythms in responsiveness to hormones contribute to this difference. male and hormone-primed female grass rats were tested for mating behavior at four different times of day (zt 5, 11, 17, 23; zt 0=lights-on). in females, there was considerable inter-individual variability with respect to patterns of responsiven ...200515579260
analysis of the prokineticin 2 system in a diurnal rodent, the unstriped nile grass rat (arvicanthis niloticus).prokineticin 2 (pk2) is a putative output molecule from the scn. pk2 rna levels are rhythmic in the mouse scn, with high levels during the day, and pk2 administration suppresses nocturnal locomotor activity in rats. the authors examined the pk2 system in a diurnal rodent, arvicanthis niloticus, to determine whether pk2 or pk2 receptors differ between diurnal and nocturnal species. the major transcript variant of a. niloticus pk2 (anpk2) encodes a 26-residue signal peptide followed by the presume ...200515851527
description of two new species of nippostrongylinae (nematoda: heligmonellidae) coparasites in three sympatric species of mastomys spp. (rodentia: muridae) from senegal.two new species of heligmosomoid trichostrongylina nematodes belonging to the genera neoheligmonella durette-desset, 1970 and heligmonina baylis, 1928 are described. they are parasitic in the small intestine of three species of mastomys from senegal living in sympatry: m. natalensis (smith, 1834), m. erythroleucus (temminck, 1853) and m. huberti (wroughton, 1909). neoheligmonella granjoni n. sp. is closely related to three species from senegal. they concern: n. bai diouf & durette-desset, 2002 a ...200819202761
leishmaniasis in sudan. cutaneous leishmaniasis.cutaneous leishmaniasis (cl) in sudan is caused by leishmania major, zymodeme lon-1. the disease is endemic in many parts of the country. the vector is phlebotomus papatasi and the animal reservoir is probably the nile rat arvicanthis niloticus. clinically, patients usually present with papules, nodules, or nodulo-ulcerative lesions, mainly on the exposed parts of the skin. in 20% of cases the parasite disseminates through the lymphatics, producing sporotrichoid-like lesions. the pathology of th ...200111370248
orexin fibers form appositions with fos expressing neuropeptide-y cells in the grass rat intergeniculate leaflet.neuropeptide-y (npy) cells in the intergeniculate leaflet (igl) are known to modulate effects of arousal on the mammalian circadian system. however, the route through which this information reaches the igl has not been established. here, we provide evidence that the orexins (hypocretins) are uniquely positioned as a potential source of activity state feedback to the igl in the grass rat, arvicanthis niloticus. specifically, many npy cells in the grass rat igl exhibit orexin-a (oxa) fiber apposit ...200516051200
temporal and spatial distribution of immunoreactive per1 and per2 proteins in the suprachiasmatic nucleus and peri-suprachiasmatic region of the diurnal grass rat (arvicanthis niloticus).the suprachiasmatic nucleus (scn) of the hypothalamus contains the primary circadian pacemaker in both diurnal and nocturnal mammals. the lower subparaventricular zone (lspv) immediately dorsal to the scn may also play an important role in the regulation of circadian rhythms. the scn contains a multitude of oscillator cells that generate circadian rhythms through transcriptional/translational feedback loops involving a set of clock genes including per1 and per2. little is known about the tempora ...200616430875
associations between behavior, hormones, and fos responses to novelty differ in pre- and post-pubertal grass animals progress from one developmental stage to the next, the nature of the challenges they face can change in systematic ways, as do the mechanisms that enable them to deal effectively with them. here we examined the changes in the behavioral patterns and neuroendocrine mechanisms associated with exposure to a novel environment before and after the transition from a pre- to a post-pubertal stage of development in the unstriped nile grass rat (arvicanthis niloticus), a murid rodent that appe ...200717055541
tyrosine hydroxylase positive neurons and their contacts with vasoactive intestinal polypeptide-containing fibers in the hypothalamus of the diurnal murid rodent, arvicanthis niloticus.diurnal and nocturnal animals differ with respect to the timing of a host of behavioral and physiological events including those associated with neuroendocrine functions, but the neural bases of these differences are poorly understood. in nocturnal species, rhythms in tyrosine hydroxylase-containing (th+) neurons in the hypothalamus appear to be responsible for rhythms in prolactin secretion. here we investigated th+ cells in a diurnal rodent (arvicanthis niloticus, the unstriped nile grass rat) ...200717368836
cholinergic projections to the suprachiasmatic nucleus and lower subparaventricular zone of diurnal and nocturnal nocturnal species cholinergic agonists alter circadian rhythm phase when injected intraventricularly or directly into the suprachiasmatic nucleus (scn), but the phase shifts obtained differ depending upon the site being injected. cholinergic projections reach the scn of nocturnal laboratory rats, however, nothing is known about these projections in diurnal rodents. the first objective of this study was to evaluate the hypothesis that cholinergic projections to the scn are only present in noct ...200717397808
a comparative analysis of the distribution of immunoreactive orexin a and b in the brains of nocturnal and diurnal rodents.the orexins (hypocretins) are a family of peptides found primarily in neurons in the lateral hypothalamus. although the orexinergic system is generally thought to be the same across species, the orexins are involved in behaviors which show considerable interspecific variability. there are few direct cross-species comparisons of the distributions of cells and fibers containing these peptides. here, we addressed the possibility that there might be important species differences by systematically ex ...200717567902
daily rhythms in per1 within and beyond the suprachiasmatic nucleus of female grass rats (arvicanthis niloticus).although circadian rhythms of males and females are different in a variety of ways in many species, their mechanisms have been primarily studied in males. furthermore, rhythms are dramatically different in diurnal and nocturnal animals but have been studied predominantly in nocturnal ones. in the present study, we examined rhythms in one element of the circadian oscillator, the per1 protein, in a variety of cell populations in brains of diurnal female grass rats. every 4 h five adult female gras ...200818692118
aav-mediated expression targeting of rod and cone photoreceptors with a human rhodopsin kinase promoter.gene therapy for retinal degeneration requires well-defined promoters that drive expression in rod and cone photoreceptors. this study was undertaken to develop short, active derivatives of the human rhodopsin kinase (rk) gene promoter for targeting transgene expression in rods and cones. rk, also known as g protein-coupled receptor kinase 1 (grk1), is a component of the light adaptation pathway expressed in rods and cones.200717724172
localization of hypocretin-like immunoreactivity in the brain of the diurnal rodent, arvicanthis niloticus.the neuropeptide hypocretin (hcrt, also called orexin) acts in the brain to increase arousal and inhibit rem sleep. there is also substantial evidence that disruption of the hypocretin system results in narcolepsy. the distribution of hcrt + fibers in nocturnal animals is consistent with its role in arousal; fibers are concentrated in brain areas important in arousal and the inhibition of rem sleep. the distribution of hcrt-like immunoreactive (hcrt +) cells and fibers has been described in noct ...200211756009
circadian phase alteration by gaba and light differs in diurnal and nocturnal rodents during the day.these studies investigated the circadian effects of light and gamma aminobutyric acid-a (gabaa) receptor activation in the suprachiasmatic nucleus (scn) of the diurnal unstriped nile grass rat (arvicanthis niloticus). microinjection of the gabaa agonist muscimol into the scn during the day produced phase shifts that were opposite in direction to those previously reported in nocturnal rodents. in addition, light had no significant effect on the magnitude of muscimol-induced phase delays during th ...200415174927
nutritional correlates and dynamics of diabetes in the nile rat (arvicanthis niloticus): a novel model for diet-induced type 2 diabetes and the metabolic syndrome.abstract:201020398338
the electroretinogram (erg) of a diurnal cone-rich laboratory rodent, the nile grass rat (arvicanthis niloticus).the most widespread models to study blindness, rats and mice, have retinas containing less than 3% cones. the diurnal rodent arvicanthis niloticus retina has around 35% cones. using erg recordings, we studied retina function in this species. several features differed from that reported in rats and mice: (a) fivefold larger photopic a-wave amplitudes; (b) photopic hill effect in nile grass rats only; and (c) flicker amplitude plateau between 5 to 35 hz with fusion beyond 60 hz in nile grass rats ...200818824014
circadian regulation of gonadotropin-releasing hormone neurons and the preovulatory surge in luteinizing hormone in the diurnal rodent, arvicanthis niloticus, and in a nocturnal rodent, rattus norvegicus.daily rhythms in the timing of the preovulatory surge and the display of reproductive behavior are reversed in diurnal and nocturnal rodents, but little is known about the neural mechanisms underlying these differences. we examined this issue by comparing a diurnal murid rodent, arvicanthis niloticus (the grass rat), to a nocturnal one, rattus norvegicus (the lab rat). in the first study, we established that sequential estradiol and progesterone treatment induces a proestrous-like rise in lh sec ...200414668212
early-phase transmission of yersinia pestis by cat fleas (ctenocephalides felis) and their potential role as vectors in a plague-endemic region of recent decades, the majority of human plague cases (caused by yersinia pestis) have been reported from africa. in northwest uganda, which has had recent plague outbreaks, cat fleas (ctenocephalides felis) have been reported as the most common fleas in the home environment, which is suspected to be a major exposure site for human plague in this country. in the past, c. felis has been viewed as only a nuisance-biting insect because limited laboratory studies suggested it is incapable of transmi ...200818541775
fos expression in the sleep-active cell group of the ventrolateral preoptic area in the diurnal murid rodent, arvicanthis niloticus.the ventrolateral preoptic area (vlpo) of the nocturnal laboratory rat receives direct input from the retina and is active during sleep; however, nothing is known about vlpo function in day-active (diurnal) species. in the first study, we used 24-h videotaping of arvicanthis niloticus, a diurnal murid rodent, to estimate the distribution of sleep and wakefulness across a 12:12 light-dark cycle. based on behavioral data, a. niloticus were perfused at a time when the animals are inactive (zeitgebe ...199910082823
daily rhythms and sex differences in vasoactive intestinal polypeptide, vipr2 receptor and arginine vasopressin mrna in the suprachiasmatic nucleus of a diurnal rodent, arvicanthis niloticus.diurnal and nocturnal animals differ with respect to the time of day at which the ovulatory surge in luteinizing hormone occurs. in some species this is regulated by the suprachiasmatic nucleus (scn), the primary circadian clock, via cells that contain vasoactive intestinal polypeptide (vip) and vasopressin (avp). here, we evaluated the hypothesis that chronotype differences in the timing of the luteinizing hormone surge are associated with rhythms in expression of the genes that encode these ne ...200919811536
neural activation in arousal and reward areas of the brain in day-active and night-active grass the diurnal unstriped nile grass rat (arvicanthis niloticus) access to a running wheel can trigger a shift in active phase preference, with some individuals becoming night-active (na), while others continue to be day-active (da). to investigate the contributions of different neural systems to the support of this shift in locomotor activity, we investigated the association between chronotype and fos expression during the day and night in three major nuclei in the basal forebrain (bf) cholinerg ...201019837140
novel phase-shifting effects of gabaa receptor activation in the suprachiasmatic nucleus of a diurnal rodent.the vast majority of neurons in the suprachiasmatic nucleus (scn), the primary circadian pacemaker in mammals, contain the inhibitory neurotransmitter gaba. most studies investigating the role of gaba in the scn have been performed using nocturnal rodents. activation of gaba(a) receptors by microinjection of muscimol into the scn phase advances the circadian activity rhythm of nocturnal rodents, but only during the subjective day. nonphotic stimuli that reset the circadian pacemaker of nocturnal ...200414656771
variation in cestode assemblages of mastomys and arvicanthis species (rodents: muridae) from lake retba in western senegal.we studied patterns of variation in cestode communities of 3 abundant rodent species that live in sympatry in the niayes of the retba lake, western senegal. we evaluated whether the host species have the same parasites and, within host species, whether the variability in parasite community is related to intrinsic (sex, age of the host individual) or extrinsic (habitat, season) factors. arvicanthis niloticus was parasitized by 2 cestode species, namely inermicapsifer madagascariensis and the high ...201020486740
compartmentalized expression of light-induced clock genes in the suprachiasmatic nucleus of the diurnal grass rat (arvicanthis niloticus).photic responses of the circadian system are mediated through light-induced clock gene expression in the suprachiasmatic nucleus (scn). in nocturnal rodents, depending on the timing of light exposure, per1 and per2 gene expression shows distinct compartmentalized patterns that correspond to the behavioral responses. whether the gene- and region-specific induction patterns are unique to nocturnal animals, or are also present in diurnal species is unknown. we explored this question by examining th ...200919393297
role of the domestic dog as a reservoir host of leishmania donovani in eastern sudan.abstract:200919534802
changing patterns of daily rhythmicity across reproductive states in diurnal female nile grass rats (arvicanthis niloticus).a suite of changes in circadian rhythms have been described in nocturnal rodents as females go through pregnancy and lactation, but there is no information on such patterns in diurnal species. as the challenges faced by these two groups of animals are somewhat different, we characterized changes in activity and core body temperature (t(b)) in female diurnal nile grass rats (arvicanthis niloticus) as they went through a series of reproductive states: virgin, pregnant, pregnant and lactating, lact ...200919744504
phase preference for the display of activity is associated with the phase of extra-suprachiasmatic nucleus oscillators within and between species.many features of the suprachiasmatic nucleus (scn) are the same in diurnal and nocturnal animals, suggesting that differences in phase preference are determined by mechanisms downstream from the scn. here, we examined this hypothesis by characterizing rhythmic expression of period 1 (per1) and period 2 (per2) in several extra-scn areas in the brains of a diurnal murid rodent, arvicanthis niloticus (grass rats). in the shell of the nucleus accumbens, dorsal striatum, piriform cortex, and ca1 of t ...201020682334
topographic arrangement of s-cone photoreceptors in the retina of the diurnal nile grass rat (arvicanthis niloticus).the retina of arvicanthis niloticus, a diurnal murine rodent closely related to rattus (rats) and mus (mice), contains approximately 30% to 35% cones and has several cone-driven functional characteristics found in humans. in this study the organization of these cone photoreceptors was examined, with emphasis on those expressing the s-opsin photopigment (s-cones).200919553614
comparative attractiveness of co(2)-baited cdc light traps and animal baits to phlebotomus duboscqi order to understand sandfly bionomics, vector species identification, and to develop methods for sandfly control, there is a need to sample sandflies in any particular habitat. this survey was aimed at determining the best method of sampling phlebotomus (phlebotomus) duboscqi (diptera: psychodidae) in the field.200919724082
parasites of the nile rat in rural and urban regions of this investigation on endoparasites (helminths) and ectoparasites of the nile rat (arvicanthis niloticus desmarest, 1822), a total of 220 nile rats were trapped from different regions of sudan during the period january 2003-january 2006. examination of different tissues, identification of parasites, effect of these parasites on the organs, the prevalence and intensity of infestation of the parasites and their relation to the habitat of the host, and sex-related infestations were considered. r ...200921392288
rhythmic cfos expression in the ventral subparaventricular zone influences general activity rhythms in the nile grass rat, arvicanthis niloticus.circadian rhythms in behavior and physiology are very different in diurnal and nocturnal rodents. a pacemaker located in the suprachiasmatic nucleus (scn) of the hypothalamus is responsible for generating and maintaining circadian rhythms in mammals, and cellular and molecular rhythms within the scn of diurnal and nocturnal rodents are very similar. the neural substrates determining whether an animal has a diurnal or nocturnal phase preference are thus likely to reside downstream of the scn. the ...200919916832
per2 rhythms in the amygdala and bed nucleus of the stria terminalis of the diurnal grass rat (arvicanthis niloticus).the suprachiasmatic nucleus (scn) of the hypothalamus is the central pacemaker that controls circadian rhythms in mammals. in diurnal grass rats (arvicanthis niloticus), many functional aspects of the scn are similar to those of nocturnal rodents, making it likely that the difference in the circadian system of diurnal and nocturnal animals lies downstream from the scn. rhythms in clock genes expression occur in several brain regions outside the scn that may function as extra-scn oscillators. in ...201020188794
distribution of orexin-a immunoreactive neurons and their terminal networks in the brain of the rock hyrax, procavia capensis.the present study describes the distribution of orexin-a immunoreactive neurons and terminal networks in relation to the previously described catecholaminergic, cholinergic and serotonergic systems within the brain of the rock hyrax, procavia capensis. adult female rock hyrax brains were sectioned and immunohistochemically stained with an antibody to orexin-a. the staining revealed that the neurons were mainly located within the hypothalamus as with other mammals. the orexinergic terminal networ ...201021126575
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