Long-term population dynamics of pinworms (Syphacia obvelata and Aspiculuris tetraptera) in mice

The population dynamics of concurrent infections of Syphacia obvelata and Aspiculuris tetraptera (Nematoda) in laboratory mice were investigated under conditions of constant re-exposure over periods of 56 and 115 days. The results indicate that A. tetraptera burdens equilibrate at a higher level than S. obvelata burdens and that both parasites become aggregated in the mouse population. Parasite burdens were higher following short-term (7 day) exposure of uninfected tracer mice to both parasites when compared with parasite burdens attained over long-term exposure, indicating probable development of immunity. A significant positive correlation was detected between numbers of immature S. obvelata and immature A. tetraptera for both experimental and tracer mice.     

Patterns of infection with the nematodes Syphacia obvelata and Aspiculuris tetraptera in conventionally maintained laboratory mice

Data on the frequency, distribution and mean intensity of the helminth fauna recovered from outbred and inbred mice conventionally maintained in Brazilian animal houses, are reported. The oxyurid nematodes Syphacia obvelata and Aspiculuris tetraptera presented overall frequencies of 91.5% and 8.5%, respectively. The frequency of S. obvelata in animals of three groups out of the four investigated ranged from 9% to 74% and A. tetraptera from 17% to 83%, since animals of one of the groups were negative for helminths. Infections due to a single species were observed in 62% of the animals, compared to 16% related to associations. The frequency of single infections in each group varied from 58.6% to 100% whereas associations varied from 24.1% to 41.4%. The analysis of specific mean intensities showed that S. obvelata was represented by 13.35 to 66.58 specimens/host and A. tetraptera by 5.85 to 16.75 specimens/host.     

Efficacy of selamectin against mites (Myobia musculi, Mycoptes musculinus and Radfordia ensifera) and nematodes (Aspiculuris tetraptera and Syphacia obvelata) in mice

The effects of selamectin were studied in mice naturally infected with the mites Myobia musculi, Myoceptes musculinus and Radfordia ensifera and with the oxyurid nematodes Aspiculuris tetraptera and Syphacia obvelata. The mice were divided into three treated and three control groups (n=9). Selamectin in the range 10-12.4 mg/kg was applied topically to the skin in a single spot at the base of the neck in front of the scapulae. The mice of treated and control groups were necropsied on the 4th, 7th and 21st day after the treatment. While selamectin was 100% effective in removing M. musculi, M. musculinus and R. ensifera by the seventh day, its effect against S. obvelata and A. tetraptera was 36.7% and 49.2%, respectively on the 21st day.     

Aspiculuris tetraptera in wild Mus musculus. The prevalence of infection in male and female mice.

A survey was carried out of the levels of infection with Aspiculuris tetraptera and Syphacia obvelata in a wild house mouse population living in the Charles Clore Small Mammals Pavilion at the London Zoo in Regent's Park. The extent of infection with A. tetraptera is analysed according to the sex of the host. It is shown that the prevalence of infection was greater in male than in female mice and frequency distribution studies suggest that this is not only because fewer female mice become infected but also because females resist larvae more effectively than do males.     

Intestinal parasites of conventionally maintained BALB/c mice and Mastomys coucha and the effects of a concomitant schistosome infection

A longitudinal study was carried out to identify the spectrum of intestinal parasites present in conventionally maintained BALB/c mice and Mastomys coucha and to determine the effects of concomitant schistosome infections on their parasite status. Six parasites were observed during the course of the study, namely the nematodes Aspiculuris tetraptera and Syphacia obvelata, Entamoeba muris and the flagellates Trichomonas muris, Spironucleus muris and Chilomastix spp. Although the 2 rodents shared common facilities, the overall prevalences of S. obvelata, T. muris and S. muris were significantly higher in M. coucha than BALB/c mice. BALB/c mice with concomitant schistosome infection had increased prevalences of E. muris, T. muris and S. muris. In M. coucha, in contrast, there were no significant increases in parasite prevalences. Infection intensities of T. muris and S. muris were significantly greater in M. coucha than BALB/c mice. Concomitant schistosome infection resulted in increased intensities of T. muris infection in BALB/c mice only. The influence of immune status in determining the susceptibilities of rodents to environmentally transmitted parasites is discussed.     

Experimental eradication of pinworms (Syphacia obvelata and Aspiculuris tetraptera) from mice colonies using ivermectin.

A spray administration of ivermectin was evaluated for the treatment of pinworm infection in mice. In this study, a spray of 0.1% ivermectin injectable solution over the entire cage once a week, for three consecutive weeks (one cycle treatment), was effective in eradicating both Syphacia obvelata and Aspiculuris tetraptera from mice under experimental conditions. In addition, no acute toxicity was observed in 105 mothers or 687 neonates treated with ivermectin, indicating that ivermectin does not affect murine reproduction. Finally, we attempted to eradicate pinworms from infected mice in our institute using this method. Two cycles of treatment were administered, with a two-week pause between cycles, resulting in complete eradication for at least one year. Treating mouse colonies with spray ivermectin is inexpensive, safe, requires very little labor and is very effective at eradicating pinworms from mice.     

Control of oxyurids in mice using thiabendazole

Mice with a natural infection of Syphacia obvelata and Aspiculuris tetraptera were continuously medicated with 0.1% thiabendazole in the diet. No oxyurids were found in test animals after 24 days of treatment though control animals remained infected. Growth rates in treated animals increased. 2 generations of mice were studied and, although overall production fell by 1.45%, the use of this drug in total eradication of the worms is suggested.     

A review of the endoparasites of wild House Mice Mus domesticus

A tabular checklist of the parasites of wild House Mice Mus domesticus is presented, with data on prevalence rates and geographic location. Parasites most often recorded are: Syphacia obvelata, Taenia taeniformis, Aspiculuris tetraptera, Hymenolepis diminuta and Trichuris maris. The near-global distribution of House Mice and their ability to survive in a wide range of conditions render House Mouse parasites ideal for the study of environmental influences on parasites and transmission of parasites to new hosts.     

妊娠期和哺乳期双酚A暴露对幼年子代小鼠焦虑和抑郁行为的影响

双酚A(bisphenol-A,BPA)对脑和行为发育的低剂量效应已引起广泛关注。本研究分别于妊娠最后2周和分娩后前2周母鼠灌胃BPA(0.4和4 mg/kg.d),然后以旷场、高架十字迷宫、明暗箱、镜子迷宫、强迫游泳和被动回避箱等模型,分别测试幼年期(生后21～28 d)子代小鼠的行为,探讨围生期不同阶段的BPA暴露对幼年仔鼠自发活动、探究、焦虑、抑郁和被动回避记忆等行为的影响。结果表明,围生期不同阶段的BPA暴露对这些行为的影响不同,主要表现为:妊娠期BPA暴露促进幼年仔鼠的活动性,减弱其焦虑状态,提高雄性仔鼠的探究能力,促进雌性仔鼠的被动回避记忆;哺乳期BPA暴露减少幼年仔鼠的活动性,但对其焦虑行为的影响相对较弱,不影响仔鼠的探究能力和被动回避记忆;而妊娠期和哺乳期BPA暴露均加剧幼年仔鼠的抑郁行为。以上结果提示,妊娠期和哺乳期BPA暴露均可影响幼年仔鼠的焦虑、抑郁、被动回避记忆等多种行为,而妊娠期可能是BPA影响的更敏感时期。     

Molecular phylogeny of the pinworms of mice, rats and rabbits, and its use to develop molecular beacon assays for the detection of pinworms in mice

Though pinworm infestation has been prevalent since the early years of laboratory animal medicine, the genomes of these parasites have not yet been sequenced. The authors used high-fidelity polymerase chain reaction to amplify a large portion of the ribosomal gene complex of four pinworm species commonly found in lab rodents and rabbits (Aspiculuris tetraptera, Passalurus ambiguus, Syphacia muris and Syphacia obvelata). They determined DNA sequences for these complexes and carried out phylogenetic analysis. Using this information, the authors developed real-time molecular beacon assays for pinworm detection, comparing the new diagnostic approach with traditional methods such as perianal tape testing, fecal flotation and direct examination of intestinal content.     

Uric acid as an inhibitor of cyclophosphamide-induced micronuclei in mice

Swiss albino male mice, 6-8 weeks old, were treated orally with different doses of uric acid dissolved in water for 7 days. Some of the mice in each group were injected i.p. with cyclophosphamide (25 mg/kg) and killed after 30 h. The blood of all animals was analyzed for uric acid levels. The femoral cells of the mice in different groups were collected and studied. Uric acid was found to be devoid of mitodepressant or clastogenic activity at 10-100 mg/kg/day. Pretreatment with uric acid was found to provide significant protection against cyclophosphamide-induced bone marrow depression and micronucleated polychromatic erythrocytes.     

Behavioral despair in mice after prenatal stress

Maternal stress during pregnancy produced behavioral alterations in both sexes with regard to sexual behavior, aggressive, maternal, lateralization and depression. In the present paper, sex differences for depression in mice was studied. No sex differences between female and male mice groups were observed either in swimming-induced immobility or in the open-field test (ambulation, rearing and boluses). Prenatal stress produced: 1) an increase of immobility time in female mice for swimming-induced immobility, but not in male mice; 2) an increase of ambulation in female mice for open-field test, but not in male mice; 3) there were no significant differences in rearing and boluses between stress and control groups either for female or male mice. Prenatal stress increases the risk of depression and locomotor activity in adult female mice.     

表达人肝再生增强因子肝细胞系生物人工肝治疗安全性的动物实验初步研究

目的：评价表达人肝再生增强因子基因的HepG2细胞系的细胞培养上清及细胞裂解物的小鼠急性毒性和近期致瘤性。方法：SPF级昆明种小鼠18只,随机分为空白对照组、细胞培养上清组、细胞裂解物组,每组小鼠各6只,腹腔分别接种空白培养液、细胞培养上清、细胞裂解物0．5ml。连续14天,每天观察记录动物毒性反应,14d后宰杀小鼠,取血测血生化指标。及观察病理改变。结果：各组小鼠均存活。除对照组1例小鼠,细胞培养上清组1例小鼠,细胞裂解物组2例小鼠次日活动稍减少外,均未见异常反应。血液生化检测ALT、AST、AFP、TBIL无明显异常,且各组间无差别。普通光镜下各组动物肝脏病理切片染色均未见明显异常。结论：目的细胞系细胞培养上清、细胞裂解物对实验用昆明小鼠无明确毒副作用及短期致瘤性。可能提供一种安全的可用于生物人工肝新的细胞来源。     

表达人肝再生增强因子肝细胞系生物人工肝治疗安全性 的动物实验初步研究

目的:评价表达人肝再生增强因子基因的HepG2细胞系的细胞培养上清及细胞裂解物的小鼠急性毒性和近期致瘤性。方法:SPF级昆明种小鼠18只,随机分为空白对照组、细胞培养上清组、细胞裂解物组,每组小鼠各6只,腹腔分别接种空白培养液、细胞培养上清、细胞裂解物0.5ml。连续14天,每天观察记录动物毒性反应,14d后宰杀小鼠,取血测血生化指标,及观察病理改变。结果:各组小鼠均存活。除对照组1例小鼠,细胞培养上清组1例小鼠,细胞裂解物组2例小鼠次日活动稍减少外,均未见异常反应。血液生化检测ALT、AST、AFP、TBIL无明显异常,且各组间无差别。普通光镜下各组动物肝脏病理切片染色均未见明显异常。结论:目的细胞系细胞培养上清、细胞裂解物对实验用昆明小鼠无明确毒副作用及短期致瘤性,可能提供一种安全的可用于生物人工肝新的细胞来源。     

Aspiculuris tetraptera in wild Mus musculus. Age resistance and acquired immunity.

Wild house mice, naturally infected with Aspiculuris tetraptera were segregated according to their weight into six age groups. The prevalence of infection and the mean worm burden of these mice were studied in the different age groups. The overall prevalence of infection was high (57% or more) in all the groups except the youngest. Mice acquired larvae soon after weaning; the highest larval burdens were reached in juvenile mice and the highest mature worm burdens, a group later, in mature mice. Older mice had fewer larvae and fewer mature worms. The mature worm burdens decreased but relatively slower than the larval burdens. It is suggested that eigher innate or acquired resistance could account for these observations.     

Syphacia obvelata in the Mongolian gerbil (Meriones unguiculatus): natural occurrence and experimental transmission

An adult from a research colony and a litter of 5-week-old Mongolian gerbils (Meriones unguiculatus) from a pet store were found to have pinworms identified as Syphacia obvelata. The infected gerbils were allowed to cohabitate with uninfected gerbils. Similarly, infected gerbils were caged with uninfected mice and infected mice with uninfected gerbils. Results of these studies showed that Syphacia obvelata can be transmitted from gerbil to gerbil, gerbil to mouse, and mouse to gerbil.     

Role of major histocompatibility complex class II in resistance of mice to naturally acquired infection with Syphacia obvelata

Genetics plays a substantial role in host resistance in many host-parasite interactions. We examined the prevalence of naturally acquired infection with Syphacia obvelata in a number of mouse strains housed in a non-barrier facility. These mice, which included cross-bred and congenic, inbred strains on various genetic backgrounds, differ in the loci for the immune function genes--major histocompatibility complex class II (MHCII), toll-like receptor 4 (Tlr4), and solute carrier family 11, member 1 (Slc11a1)--which allowed comparisons of the impact of these genes on resistance to pinworm infection. Male and female mice of various ages were sampled over an 18-month period; infection was determined by use of the cellophane tape test. Results indicated that mice that were MHCII+/+ had a significantly lower prevalence of infection than did mice that were MHCII-/-. Differences were not seen between male and female mice. Although MHCII+/+ mice had an age-associated decrease in infection prevalence, such decrease was not seen in MHCII-/- mice. In contrast, infection prevalence in mice with the normal Tlr4 gene (Tlr4(LPS-n/LPS-n)) gene did not differ significantly compared with that in mice that were homozygous for either the point mutation (Tlr4(LPS-d/LPS-d)) or deletion (Tlr4(LPS-del/LPS-del)) of that gene. Likewise, the presence (Sle11a1r/r) or absence (Slc11a1s/s) of functional alleles for Slc11a1 had no effect on the prevalence of infection with S. obvelata. In conclusion, presence of MHCII, but not Tlr4 or Slc11a1 significantly influences prevalence of naturally acquired infection with S. obvelata. These data justify further comprehensive analyses of the immune components that are involved in pinworm resistance.     

Effect of chronic ivermectin treatment on GABA receptor function in ethanol withdrawal-seizure prone and resistant mice

Ivermectin, a potent, effective anthelmintic, is easy to administer, has a broad spectrum of action and a wide safety margin. However, no testing has been done in hosts genetically selected for seizure susceptibility which may be more sensitive to the effects of ivermectin than other animals. This was done in the present experiments with seizure prone and seizure resistant mice infested with Syphacia obvelata (pinworm). These subjects were treated daily with oral ivermectin in their drinking water every other week for six weeks, for a total of 21 days. The treatment cleared the mice of the pinworm infestation, but did not alter the seizure susceptibility or binding parameters of [3H]flunitrazepam in either of the selected lines.     

Suppression of expulsion of Aspiculuris tetraptera in hydrocortisone and methotrexate treated mice.

Hydrocortisone treated male and female mice, given a primary infection with Aspiculuris tetraptera, did not reject the worms during the third week of infection. Mice given hydrocortisone during the first week of infection had elevated worm burdens on day 10, suggesting that some worm loss was encountered during the anterior migration in control mice. Furthermore, this temporary period of treatment was sufficient totally to suppress rejection and to allow the parasite to persist until day 28. Methotrexate also significantly delayed rejection, but larval growth was retarded in treated mice. These results, it is suggested, add strength to the hypothesis that the loss of A. tetraptera in a primary infection in mice, is an immunological phenomenon.     

Age-related changes of epidermal cell kinetics in the hairless mouse

Cell kinetic variables in normal untreated hairless mice were studied in order to observe possible age-related changes. Generally, groups of 4 male and 4 female mice were subjected to study at various ages from one to 115 weeks. The number of basal and suprabasal cells per microscopic field was observed, and after injection of tritiated thymidine the mean labelling index, the average specific activity and the mean grain count were scored. After injection of Colcemid, the average number of Colcemid-arrested mitoses was counted. With flow cytometry the fraction of cells in S and in G2 + M was also observed. In general, both the number of suprabasal cells and the proliferative variables were significantly lower in the very young mice. They increased to slightly above normal values at about 20-22 weeks of age, and then fluctuated a little with two additional possible peaks at 40-50 and around 80 weeks, respectively, and two troughs some weeks after the peaks. However, this rhythmicity was slight and not significant. Thus the only significant age-related pattern was that very young mice have a thin epidermis and low proliferative variables. These values increase up to the age of 20 weeks, and from then on there are no obvious and significant alterations, only slight rhythmic undulations almost within normal limits. The importance of cell kinetic changes with age for epidermal carcinogenesis is discussed in relation to these observations.