(1/1520) The prevalence of Balantidium coli infection in fifty-six mammalian species.
A total of 375 fecal samples of 56 mammalian species belonging to 17 families of 4 orders were examined for the detection of Balantidium coli from December 1994 to August 1995. As a result, B. coli was found from 6 species belonging to 4 families of 2 orders (Primates and Artiodactyla) of host animals examined. White-handed gibbon (Hylobates lar), squirrel monkey (Saimiri sciurea) and Japanese macaque (Macaca fuscata) were new hosts for B. coli. All the wild boar (Sus scrofa) and chimpanzee (Pan troglodytes) examined were positive. The highest number of B. coli was obtained from a chimpanzee (1,230/g feces). No B. coli was detected from the animals of orders Rodentia and Carnivora including dogs and cats. The rarity of B. coli infection in breeding animals in Japan. suggests that there is no serious problem in controlling infections. (+info)
(2/1520) Isolation of tick-borne encephalitis virus from wild rodents and a seroepizootiologic survey in Hokkaido, Japan.
To determine the vertebrate host of tick-borne encephalitis (TBE) virus in the southern part of Hokkaido, Japan, virus isolation was performed using spleens from small mammals captured in the area. Two virus strains were isolated, one strain from Apodemus speciosus and another from Clethrionomys rufocanus. Virus isolates were inoculated onto baby hamster kidney cell monolayers and antigen slides were prepared for an indirect immunofluorescent antibody assay. Two isolates were identified as TBE viruses by monoclonal antibody reactions. To specify the TBE-endemic area in Hokkaido, rodent, horse, and dog sera collected from 1992 to 1997 were tested for neutralization antibody against TBE virus previously isolated from a dog. The positive cases were distributed in four districts in the southern part of Hokkaido. (+info)
(3/1520) Specific interaction of Tat with the human but not rodent P-TEFb complex mediates the species-specific Tat activation of HIV-1 transcription.
Tat stimulation of HIV-1 transcriptional elongation is species-specific and is believed to require a specific cellular cofactor present in many human and primate cells but not in nonpermissive rodent cells. Human P-TEFb, composed of Cdk9 and cyclin T1, is a general transcription elongation factor that phosphorylates the C-terminal domain of RNA polymerase II. Previous studies have also implicated P-TEFb as a Tat-specific cellular cofactor and, in particular, human cyclin T1 as responsible for the species-specific Tat activation. To obtain functional evidence in support of these hypotheses, we generated and examined the activities of human-rodent "hybrid" P-TEFb complexes. We found that P-TEFb complexes containing human cyclin T1 complexed with either human or rodent Cdk9 supported Tat transactivation and interacted with the Tat activation domain and the HIV-1 TAR RNA element to form TAR loop-dependent ribonucleoprotein complexes. Although a stable complex containing rodent cyclin T1 and human Cdk9 was capable of phosphorylating CTD and mediating basal HIV-1 elongation, it failed to interact with Tat and to mediate Tat transactivation, indicating that the abilities of P-TEFb to support basal elongation and Tat activation can be separated. Together, our data indicated that the specific interaction of human P-TEFb with Tat/TAR, mostly through cyclin T1, is crucial for P-TEFb to mediate a Tat-specific and species-restricted activation of HIV-1 transcription. Amino acid residues unique to human Cdk9 also contributed partially to the formation of the P-TEFb-Tat-TAR complex. Moreover, the cyclin box of cyclin T1 and its immediate flanking region are largely responsible for the specific P-TEFb-Tat interaction. (+info)
(4/1520) A longitudinal study of Sin Nombre virus prevalence in rodents, southeastern Arizona.
We determined the prevalence of Sin Nombre virus antibodies in small mammals in southeastern Arizona. Of 1,234 rodents (from 13 species) captured each month from May through December 1995, only mice in the genus Peromyscus were seropositive. Antibody prevalence was 14.3% in 21 white-footed mice (P. leucopus), 13.3% in 98 brush mice (P. boylii), 0.8% in 118 cactus mice (P. eremicus), and 0% in 2 deer mice (P. maniculatus). Most antibody-positive mice were adult male Peromyscus captured close to one another early in the study. Population dynamics of brush mice suggest a correlation between population size and hantavirus-antibody prevalence. (+info)
(5/1520) Statistical sensitivity for detection of spatial and temporal patterns in rodent population densities.
A long-term monitoring program begun 1 year after the epidemic of hantavirus pulmonary syndrome in the U.S. Southwest tracked rodent density changes through time and among sites and related these changes to hantavirus infection rates in various small-mammal reservoir species and human disease outbreaks. We assessed the statistical sensitivity of the program's field design and tested for potential biases in population estimates due to unintended deaths of rodents. Analyzing data from two sites in New Mexico from 1994 to 1998, we found that for many species of Peromyscus, Reithrodontomys, Neotoma, Dipodomys, and Perognathus, the monitoring program detected species-specific spatial and temporal differences in rodent densities; trap-related deaths did not significantly affect long-term population estimates. The program also detected a short-term increase in rodent densities in the winter of 1997-98, demonstrating its usefulness in identifying conditions conducive to increased risk for human disease. (+info)
(6/1520) Long-term studies of hantavirus reservoir populations in the southwestern United States: a synthesis.
A series of intensive, longitudinal, mark-recapture studies of hantavirus infection dynamics in reservoir populations in the southwestern United States indicates consistent patterns as well as important differences among sites and host-virus associations. All studies found a higher prevalence of infection in older (particularly male) mice; one study associated wounds with seropositivity. These findings are consistent with horizontal transmission and transmission through fighting between adult male rodents. Despite very low rodent densities at some sites, low-level hantavirus infection continued, perhaps because of persistent infection in a few long-lived rodents or periodic reintroduction of virus from neighboring populations. Prevalence of hantavirus antibody showed seasonal and multiyear patterns that suggested a delayed density-dependent relationship between prevalence and population density. Clear differences in population dynamics and patterns of infection among sites, sampling periods, and host species underscore the importance of replication and continuity of long-term reservoir studies. Nevertheless, the measurable associations between environmental variables, reservoir population density, rates of virus transmission, and prevalence of infection in host populations may improve our capacity to model processes influencing infection and predict increased risk for hantavirus transmission to humans. (+info)
(7/1520) Nuclear bodies are usual constituents in tissues of hibernating dormice.
In previous studies we demonstrated in several tissues of the hazel dormouse Muscardinus avellanarius that during hibernation cell nuclei contain particular structural constituents absent in euthermia. In the present study we examine the same tissues in euthermic and hibernating individuals of the edible dormouse Glis glis in order to investigate possible modifications of nuclear structural constituents occurring during hibernation in this species. Edible dormice were captured in the wild and maintained in an external animal house. Samples of liver, pancreas, brown adipose tissue and adrenal cortex were taken from three hibernating and three euthermic animals and processed for resin embedding. Ultrastructural and immunocytochemical studies were carried out on cell nuclei of these tissues. The most evident feature of cell nuclei of hibernating dormice was the presence of several nuclear bodies, namely fibro-granular material, amorphous bodies, coiled bodies, perichromatin granule-like granules and nucleoplasmic fibrils, the distribution of which was peculiar to each tissue. No one of these constituents was detectable during euthermia. Immunocytochemical analyses revealed that they contain some splicing factors. Apart from some differences, maybe due to the different characteristics of lethargy, the nuclear bodies found in edible dormice were morphologically and immunocytochemically similar to those previously described in the same tissues of hazel dormice. They therefore seem to be strictly correlated to the hibernating state. If they represent storage and/or assembly sites of splicing factors to be rapidly used upon arousal, they could represent a usual structural feature in cells of hibernating species. (+info)
(8/1520) Evaluation of the APOH gene as a positional candidate for prcd in dogs.
PURPOSE: Progressive rod-cone degeneration (prcd) is an autosomal recessive retinal degeneration of dogs characterized by abnormalities in lipid metabolism. It has recently been mapped to the centromeric region of canine chromosome 9, homologous to human 17q, which contains the apolipoprotein H (apoH, protein; APOH, gene) gene involved in lipid metabolism and regulation of triglycerides. The present study was undertaken to evaluate APOH as a positional candidate for prcd. METHODS: Expression of APOH in the retina was examined by reverse transcription-polymerase chain reaction (RT-PCR) and by immunocytochemistry in normal and prcd-affected dogs. The level of apoH in the plasma was determined by western blot analysis. Intragenic polymorphic markers were identified and typed in the prcd pedigree. Canine-rodent hybrid cell lines were analyzed to detect canine APOH. RESULTS: ApoH has been localized to the photoreceptor outer segment layer by immunocytochemistry. Its expression in the retina of normal and prcd-affected dogs was confirmed by RT-PCR. The levels of antihuman apoH cross-reacting material in plasma were similar in all dogs, regardless of disease status. Finally, linkage analysis of the APOH gene with the disease locus in the prcd pedigree detected 3 recombinants among 70 informative offsprings (lod score 15.09 at 0 = 4.3 centimorgan [cM]). CONCLUSIONS: APOH is expressed in the retina and tightly linked to the prcd locus. However, despite its potential role in phenotypes of abnormal lipid metabolism associated with prcd, the gene has been excluded as a primary candidate for prcd by linkage analysis. (+info)