Adequate selection of antigens for serologic diagnostics of experimental melioidosis

Sera of Burkholderia pseudomallei-infected golden hamsters, white mice, guinea pigs and white rats were studied. Immunochemical analysis revealed presence of antibodies against antigens 2, 3, 6, d, and g with significant predominance of antibodies to antigens 6 and d. Antigen d was detected irrespectively to strain used for experimental infection and experimental animal species. Antibodies to antigen 6 were detected only when strains belonging to Asian serovar, but not to Australian serovar, were used. On the basis of antigens 6 and d following methods of serologic diagnostics were developed: reaction of indirect hemagglutination, reaction of latex agglutination, and radioimmunological assay. Their sensitivity and specificity reached 100% during experimental melioidosis in golden hamsters, guinea pigs and white rats.     

Biological effects of Spirometra erinacei plerocercoids in several species of rodents

Observations were made of the biological effects on infection with plerocercoids of Spirometra erinacei on normal female Snell mice, male chinese hamsters, golden hamsters, normal and hypox rats. Plerocercoid infection caused the strongest growth-promoting effect on normal Snell mice. In mice, this effect appears to be independent of strain. Chinese hamsters infected with these larvae showed similar growth. The infected normal rats and golden hamsters, however, showed a weight increase in the skeletal muscle only, while the hypox rats exhibited no effect at all. The elevation in the concentration of serum triglyceride was observed in all the animals investigated except for rats. Golden hamsters, in particular, exhibited a marked increase in the concentration of serum free fatty acids and total cholesterol. There was close correlation between the concentrations of serum triglyceride and free fatty acids, and the regression coefficient of the resulting linear regression equation for the experimentals was higher than that for the controls. This suggests that serum triglyceride results from an increased concentration of serum free fatty acids derived from stimulated lipolysis. The total cholesterol concentration in the serum decreased in chinese hamsters infected with larvae. The serum glucose concentration increased in normal Snell mice but decreased in chinese and golden hamsters. No difference in glycerol and free fatty acid concentration was observed in infected animals except for golden hamsters.     

The life cycle and transmission dynamics of the larval stages of Hypoderaeum conoideum

The morphology of the different larval stages and life cycle of Hypoderaeum conoideum (Trematoda: Echinostomatidae) are described. The freshwater snail species Lymnaea peregra (Gastropoda: Lymnaeidae) serves as the natural first intermediate host and this and L. corvus serve as experimental first intermediate hosts. These and other freshwater snails, such as Physella acuta and Gyraulus chinensis, in turn serve as second intermediate hosts. Adult worms were obtained from chicks and ducks, but not from rats, mice and golden hamsters. The morphology of the larval stages is compared with previous work on H. conoideum. Several aspects of the biology of the life history stages are described with emphasis on the transmission dynamics of the free-living stages. Differential suitability of the snail species that may act as first and/or second intermediate hosts is studied and discussed.     

Antibodies in the serum of golden hamsters experimentally infected with the intestinal trematode Echinostoma caproni.

The serum antibody response in golden hamsters (Mesocricetus auratus) infected with the intestinal trematode Echinostoma caproni was examined with ELISA, SDS-PAGE and Western blot, and IFAT techniques. All methods showed that the hamsters responded slowly but developed a clear positive humoral response to the infection. In most hamsters, an antibody response to infection could not be detected earlier than 11-13 weeks after infection with 6 or 25 metacercariae, and responses were weak when compared to previous results from mice infected with the same parasite. IFAT with positive hamster sera on live juvenile E. caproni showed only fluorescence at the posterior tip, which is a different pattern from that seen using from infected mice, indicating a different response to antigens on the juvenile parasites by these two hosts. The results are discussed in relation to the limited selfcure and development of resistance which is observed in golden hamsters infected with E. caproni.     

Transmission and adaptation of chronic wasting disease to hamsters and transgenic mice: evidence for strains

In vitro screening using the cell-free prion protein conversion system indicated that certain rodents may be susceptible to chronic wasting disease (CWD). Therefore, CWD isolates from mule deer, white-tailed deer, and elk were inoculated intracerebrally into various rodent species to assess the rodents' susceptibility and to develop new rodent models of CWD. The species inoculated were Syrian golden, Djungarian, Chinese, Siberian, and Armenian hamsters, transgenic mice expressing the Syrian golden hamster prion protein, and RML Swiss and C57BL10 wild-type mice. The transgenic mice and the Syrian golden, Chinese, Siberian, and Armenian hamsters had limited susceptibility to certain of the CWD inocula, as evidenced by incomplete attack rates and long incubation periods. For serial passages of CWD isolates in Syrian golden hamsters, incubation periods rapidly stabilized, with isolates having either short (85 to 89 days) or long (408 to 544 days) mean incubation periods and distinct neuropathological patterns. In contrast, wild-type mouse strains and Djungarian hamsters were not susceptible to CWD. These results show that CWD can be transmitted and adapted to some species of rodents and suggest that the cervid-derived CWD inocula may have contained or diverged into at least two distinct transmissible spongiform encephalopathy strains.     

Infectivity, growth, survival, and pathogenicity of Zygocotyle lunata (Trematoda) in experimental rodent hosts

Laboratory mice, rats, and golden hamsters were fed metacercarial cysts of Zygocotyle lunata to examine infectivity, growth, survival, and pathogenicity of this trematode. All 3 rodent types became infected with Z. lunata. Eggs of Z. lunata were seen in the feces of the hamsters by day 21, in mice by day 26, and in rats by day 44. Eggs teased from worms and embryonated in tap water hatched from day 21 to day 26 for rats and mice and from day 40 to day 45 for hamsters. The body areas of sexually mature worms were similar in all 3 types of rodent species. It was possible to reinfect all 3 species with Z. lunata metacercariae. No sign of clinical amphistomiasis was evident in the experimental animals. The histopathological responses were progressive, and severity was related to the age of the infection and the number of worms in the infection.     

Comparative efficiency of infecting laboratory animals via intravenous and subcutaneous administration of Schistosoma mansoni cercaria

Comparative study on effectiveness of intravenous and subcutaneous methods of infection of animals has shown that infection rate of helminths after the injection of equal dozes of cercariae under skin, into portal and femoral veins of golden hamsters does not differ significantly (42.6 +/- 4.2, 37.8 +/- 5.8 and 26.0 +/- 6.6 schistosomes, respectively). When using the above methods for cotton rats the infection rate was lower than that in golden hamsters. The most insignificant infection rate of parasites was recorded in both species after the injection of cercariae into the femoral vein. Results of the infection of golden hamsters with different dozes of cercariae have shown that with the increase of dozes of infectious material the infection rate of helminths rises during the experimental intestinal schistosomiasis only to a definite level, which is attained by the injection of cercariae into the portal vein in dozes lower than those used for subcutaneous infection.     

Life-cycle of Euparyphium albuferensis n. sp. (Trematoda: Echinostomatidae) from rats in Spain

The morphology of the different life-history stages and life-cycle of Euparyphium albuferensis are described and drawn. The freshwater snail Gyraulus chinensis (Gastropoda: Planorbidae) serves as the natural and experimental first intermediate host. This and other freshwater snails, such as Lymnaea truncatula, L. peregra, L. palustris and Physa acuta, serve as second intermediate hosts. Adult worms, possessing 45 collar spines, were obtained naturally from Rattus norvegicus and R. rattus, and experimentally from albino rats, mice and golden hamsters. Chickens, ducks and pigeons were not suitable experimental definitive hosts. E. albuferensis differs from the most closely related species, E. murinum Tubangui, 1931, in its larger body, suckers and oesophageal measurements, in the distribution of vitelline follicles and in the morphology of the collar spines.     

Effect of various adaptational temperatures on oxidative capacity of the brown adipose tissue.

Changes in total weight, protein content and activity of cytochrome oxidase have been followed in the brown adipose tissue (BAT) of golden hamsters, white mice and white rats adapted to various temperatures. Important interspecies differences have been detected. The weight and the cytochrome oxidase activity of the BAT of the white mouse changes little under the influence of different adaptational temperatures, whereas in the white rat and in the golden hamster a decrease of adaptational temperature considerably increases the total weight, protein content and cytochrome oxidase activity of this organ. Different adaptational temperatures induce variable effects on the BAT of the golden hamster. Mild cold stimuli favour the accumulation of proteins and of oxidative enzymes, in particular. Severe cold stress also induces growth processes, so that the weight of the BAT increases proportionally to the total body weight of animals. The metabolic capacity of the BAT, measured as total cytochrome oxidase activity, changes substantially with decreasing temperature of adaptation in all species studied, increasing twice, six times and almost twelve times in the mouse, rat and golden hamster, respectively.     

Helicobacter bilis/Helicobacter rodentium co-infection associated with diarrhea in a colony of scid mice

An outbreak of diarrhea spanning 3 months occurred in a breeding colony of scid/Trp53 knockout mice. Approximately a third of the 150 mice were clinically affected, with signs ranging from mucoid or watery diarrhea to severe hemorrhagic diarrhea with mortality. Helicobacter bilis and the newly recognized urease-negative organism H. rodentium were isolated from microaerobic culture of feces or cecal specimens from affected mice. Dual infection with H. bilis and H. rodentium were confirmed by culture and polymerase chain reaction (PCR) in several animals. Both Helicobacter species rapidly colonized immunocompetent sentinel mice exposed to bedding from cages containing affected mice, but the sentinel remained asymptomatic. Mice with diarrhea had multifocal to segmental proliferative typhlitis, colitis, and proctitis. Several affected mice had multifocal mucosal necrosis with a few focal ulcers in the cecum, colon, and rectum. Mice with diarrhea were treated with antibiotic food wafers (1.5 mg of amoxicillin, 0.69 mg of metronidazole, and 0.185 mg of bismuth/mouse per day) previously shown to eradicate H. hepaticus in immunocompetent mice. Antibiotic treatment resulted in resolution of diarrhea, but not eradication of H. bilis and H. rodentium; mice continued to have positive PCR results after a 2-week treatment regimen, and clinical signs of diarrhea returned in some mice when treatment was suspended. To the authors' knowledge, this is the first report of natural infection with either H. bilis and/or H. rodentium causing acute diarrheal disease and suggests that H. bilis and/or H. rodentium can be an important pathogen for scid mice.     

Helicobacter bilis-associated hepatitis in outbred mice

Although Helicobacter bilis infects mice worldwide, it is not known whether H. bilis causes enterohepatic disease in outbred Swiss Webster (SW) mice. Intestinal and liver specimens from four groups of 39 SW mice, five of which were treated with creatine in the drinking water, were obtained for culture for the presence of H. bilis and were analyzed as to whether infection status was associated with H. bilis seroconversion and/or hepatitis. Helicobacter bilis was isolated from the colon of all 27 mice of groups I-III, but only from the liver of one 12- to 13-month-old female mouse. Ten of 27 livers were H. bilis-positive based on polymerase chain reaction (PCR) analysis; 8 of 10 (80%) of the positive results were for older mice. Results of PCR analysis for H. bilis were negative, and H. bilis was not isolated from 12 control mice (group IV). Irrespective of treatment group or controls, severity of histologic lobular and periportal chronic inflammatory lesions in the liver of H. bilis-infected outbred mice ranged from minimally to moderately severe. Helicobacter bilis infection was associated with increased portal inflammation in group III mice, compared with age-matched, helicobacter-free, group IV mice (P < 0.03). A comparison of potential sex effects in group III mice indicated that H. bilis-infected female mice developed more severe portal inflammation than did H. bilis-infected male mice (P < 0.01). On the basis of results of an ELISA, 8 of 11, 6- to 8-month-old H. bilis-infected mice of group III seroconverted to H. bilis outer membrane antigen. Helicobacter bilis infection is associated with hepatitis in SW mice and can confound experimental results.     

Extraintestinal strobilar development of immature Echinococcus multilocularis in laboratory rodents following intratracheal inoculation of the protoscoleces

Intratracheal inoculation of Echinococcus multilocularis protoscoleces was performed in prednisolone tertiary-butylacetate(PTBA)-treated and untreated golden hamsters and AKR/J mice. Repeated PTBA treatments prior to the day of inoculation prevented the influx of neutrophils against the cestode. More than 1 month after infection, living immature adult forms of E. multilocularis, showing some somatic prolongation, were recovered from the pulmonary alveolar space of PTBA-treated golden hamsters, in the absence of any cystic development.     

Sensibilité comparée de divers animaux de laboratoire à l'infection par instillations nasales de la phase saprophytique d'Emmonsia crescens Emmons & Jellison, 1960: Fréquence et intensité du parasitisme,réactions histopathologiques

Comparative observations were made on the development of Emmonsia crescens in the lungs of laboratory rats and mice, golden hamsters and guinea pigs after a nasal instillation of a heavy suspension of the saprophytic phase of the fungus. 95% of 80 experimental rats were found to be parasited against 80% of 200 inoculated mice, while only 30% of 70 hamsters and all of 4 guinea pigs showed an infection. The lungs of the mice, rats and guinea pigs were frequently more heavily infected than those of the hamsters. In addition, the adiaspores obtained from the mice and rats had, on average, a diameter double those from the hamsters and their walls were thicker. Thus, the laboratory mice and rats were shown to be better hosts of E. crescens than were golden hamsters.     

Experimental models of cutaneous leishmaniasis in laboratory animals

A survey of literature on modelling cutaneous leishmaniasis of man (common and metastatic) on some lines of mice, guinea pigs, golden hamsters infected with different species of Leishmania is given. Merits and demerits of each described model are pointed out.     

Use of the P167 recombinant antigen for serodiagnosis of Helicobacter bilis

Helicobacter bilis is widespread among research mouse colonies. Serodiagnosis of Helicobacter infections involves use of bacterial lysates or membrane antigen preparations that lack specificity, necessitating the need to identify a specific and sensitive antigen. A previously reported recombinant protein (P167) was evaluated for use as an H. bilis-specific antigen for serologic testing. Seventy-six mice naturally infected with Helicobacter spp. were identified from commercially bred or sentinel mice. Infection was confirmed and speciated by use of cecal specimen culture and fecal polymerase chain reaction (PCR) analysis, followed by restriction enzyme digest of the amplicon. Forty-one mice were determined to be monoinfected with H. bilis, 27 mice were determined to be monoinfected with H. hepaticus, and eight mice were infected with another species of Helicobacter. Serum was diluted 1:100 to evaluate the immunoreactivity to enzyme-linked immunosorbent assay preparations of H. bilis membrane extract and the immunodominant C and D fragments of the p167 gene. The sensitivity was greatest for the membrane extract preparation (76%), whereas sensitivity to the P167C and D recombinants was lower (62 and 51%, respectively). However, the specificity of the membrane extract preparation was low (87%), compared with the much improved specificity of the recombinant P167C and D fragments (96 and 96%, respectively). These findings suggest that the recombinant P167C and D fragments of the p167 gene product from H. bilis can be used as specific reagents in the serodiagnosis of H. bilis infection in mice.     

Mallard ducklings (Anas platyrhynchos) experimentally infected with Echinostoma trivolvis (Digenea)

Of 8, day-old mallard ducklings, each fed 50 encysted metacercariae of Echinostoma trivolvis, 4 (50%) were infected 15-31 days postinfection (PI) with a total of 10 (2.5%) worms. The worms were attached loosely to the mucosa of the lower ileum and rectum-cloaca, and some were ovigerous by day 15 PI. Ducklings, 4-14 days old when fed encysted metacercariae, became infected with E. trivolvis adults, but ducks 150 days old were refractory to infection. Compared to our previous studies on experimental infections of echinostomes, mallard ducklings were less susceptible than golden hamsters to E. trivolvis.     

Age-dependent resistance to Cryptosporidium muris (strain MCR) infection in golden hamsters and mice

An age-dependent aspect of resistance to Cryptosporidium muris (strain MCR) infection was monitored in Syrian golden hamsters, Mesocricetus auratus, at 1-, 5- and 10-week of age and in ICR mice. Mus musculus, at 3-, 12-, and 15-week of age orally inoculated with a single dose of 2 x 10(6) oocysts, respectively. The prepatent periods for both animals were similar, independent of age, but the patency was significantly longer in younger hamsters (P < 0.001) and a long tendency in younger mice. Hamsters infected at 1-week of age excreted about 10 times higher oocysts than those at 5- and 10-week of age. However, the total oocyst output was similar among mice of different ages. There was a good correlation between the length of the patency and the total oocyst output in hamsters (R = 0.9646), but not in mice (R = 0.4561). The immunogenicity of the parasite to homologous challenge infections was very strong in hamsters and relatively strong in mice. These results indicate that acquired resistance to C. muris infection is age-related and the innate resistance is independent of age of hamsters, and that both innate and acquired resistance, on the contrary, are irrespective of age of mice.     

Changes in brain ganglioside composition of normothermic and hibernating golden hamsters (Mesocricetus auratus).

1. Brain ganglioside patterns of normothermic and hibernating golden hamsters (Mesocricetus auratus) and laboratory mice had been investigated. 2. The ganglioside pattern of normothermic golden hamsters in comparison to that of mice is characterized by an unusual high amount of the polar trisialoganglioside GT1. 3. In the hibernating golden hamster in contrast to normothermic counterparts the brain gangliosides are more polar (polysialization-effect). 4. The results are discussed with regard to the hypothesis that neuronal membranes provided with more polar gangliosides at lower environmental temperatures might be more efficient with respect to the high complexation ability of gangliosides with Ca2+-ions.     

Evidence for conserved function of γ-glutamyltranspeptidase in Helicobacter genus

The confounding consequences of Helicobacter bilis infection in experimental mice populations are well recognized, but the role of this bacterium in human diseases is less known. Limited data are available on virulence determinants of this species. In Helicobacter pylori, γ-glutamyltranspeptidase (γGT) contributes to the colonization of the gastric mucosa and to the pathogenesis of peptic ulcer. The role of γGT in H. bilis infections remains unknown. The annotated genome sequence of H. bilis revealed two putative ggt genes and our aim was to characterize these H. bilis γGT paralogues. We performed a phylogenetic analysis to understand the evolution of Helicobacter γGTs and to predict functional activities of these two genes. In addition, both copies of H. bilis γGTs were expressed as recombinant proteins and their biochemical characteristics were analysed. Functional complementation of Esherichia coli deficient in γGT activity and deletion of γGT in H. bilis were performed. Finally, the inhibitory effect of T-cell and gastric cell proliferation by H. bilis γGT was assessed. Our results indicated that one gene is responsible for γGT activity, while the other showed no γGT activity due to lack of autoprocessing. Although both H. bilis and H. pylori γGTs exhibited a similar affinity to L-Glutamine and γ-Glutamyl-p-nitroanilide, the H. bilis γGT was significantly less active. Nevertheless, H. bilis γGT inhibited T-cell proliferation at a similar level to that observed for H. pylori. Finally, we showed a similar suppressive influence of both H. bilis and H. pylori γGTs on AGS cell proliferation mediated by an apoptosis-independent mechanism. Our data suggest a conserved function of γGT in the Helicobacter genus. Since γGT is present only in a few enterohepatic Helicobacter species, its expression appears not to be essential for colonization of the lower gastrointestinal tract, but it could provide metabolic advantages in colonization capability of different niches.     

金色中仓鼠不存在布鲁斯效应

布鲁斯效应是一种由非配偶雄性的化学信号所诱发的雌性妊娠终止现象,曾被认为是雌性对抗雄性杀婴行为的一种进化策略。布鲁斯效应最初在实验小鼠中发现。后续的研究证明了在实验室条件下多种啮齿类动物中存在布鲁斯效应。布鲁斯效应是否为实验室啮齿类动物中存在的普遍规律,目前尚无定论。本实验首先探讨了布鲁斯效应在金色中仓鼠中是否存在。在交配之后给予实验组雌鼠陌生雄鼠的非直接接触刺激,对照组雌鼠接受配偶雄鼠的非直接接触刺激。同时还测定了雌鼠的体重、胚胎质量以及生理器官(肾上腺、脾脏、卵巢和子宫)质量。结果显示,实验组雌鼠的流产率、体重、胚胎质量、生理器官(肾上腺、脾脏、卵巢、子宫)质量与对照组不存在显著差异。本实验结果表明:陌生雄鼠的化学信号对雌性金色中仓鼠的怀孕状态没有影响,实验室条件下的金色中仓鼠不存在布鲁斯效应。