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1.
Experimental inoculations of 1000 Toxocara cati larval eggs were carried out in 18 BALB/c mice. The T. cati eggs used for inoculation were collected from the faeces of naturally infected cats. Euthanasia was performed on two mice on days 1, 2, 3, 4, 5, 6, 14, 21 and 28 post-inoculation (p.i.). Tissue samples were taken for digestion and histopathology. Larvae were recovered from all infected mice and the average of all larvae recovered was 28.3% (95%; CI: 14.1-42.4). Maximum number was obtained from liver on days 1 and 2 p.i.; from the lung on day 2 p.i. and from the brain on day 28 p.i. In muscle, the recovery was high as from day 3 p.i., with the maximum obtained on day 28 p.i. Superficial foci of congestion and haemorrhage were macroscopically observed in the lungs between days 2 and 5 p.i. and in the brain between days 3 and 6 p.i. Microscopic lesions were observed in the liver between days 2 and 14 p.i., with periportal and subcapsule inflammatory infiltrates. In the lungs, haemorrhages and inflammatory infiltrates can be observed in the alveolar parenchyma, close to bronchioles and large blood vessels. In the brain, congestive areas without inflammatory reactions were seen. In muscle, the presence of inflammatory infiltrates and degenerated muscle can be observed surrounding a parasite larva. These same lesions were observed in myocardium and pericardium. The kidneys were congested with inflammatory infiltrates. The inflammatory cells present in all the tissues studied were lymphocytes, neutrophils and a few eosinophils. Formation of granulomas or signs of larva encapsulation were not observed. The migratory pattern of T. cati larvae in BALB/c mice and its tendency to become concentrated in the muscle reinforce the importance of the mouse as a paratenic host for the parasite's cycle in the environment.  相似文献   

2.
Toxocara canis is a nematode of the Ascaridae family that normally parasites the small intestine of canid species. Humans are accidentally infected upon ingestion of embryonated eggs, and can manifest several clinical alterations such as fever, hepatomegaly, splenomegaly, respiratory symptoms, muscle pain and anorexia. In the present work, we investigated the kinetics of tissue distribution of L2 larva in lungs, liver, kidney, brain, skeletal muscle and myocardium. Also, we analyzed the blood and bronchoalveolar lavage fluid (BAL) for levels of IL-6, IFN-gamma, eotaxin and Regulated on Activation Normal T Cell Expressed and Secreted (RANTES) in experimental murine T. canis infection. We observed liver, lung and kidney lesions correlated to larva migration as early as the first day of infection. After the seventh post-infection day, larva could also be detected in brain, skeletal muscle and heart, as an indicator of biphasic migration pattern. Increased inflammatory activity was detected in BAL and plasma of infected animals, as was an intense eosinophil migration associated with an increase in the levels of all the cytokines studied. In conclusion, our results establish a tight correlation between tissue lesions caused by larva migration and increased plasma levels of pro-inflammatory and eosinophil chemotactic cytokines. Thus, murine T. canis infection may prove to be useful in understanding the role of cytokines in infection.  相似文献   

3.
A Western blotting procedure with excretory/secretory antigens from Toxocara canis larvae was developed for immunodiagnosis of visceral larva migrans in mice. In this study, eighty Swiss albino mice were allotted into two groups of 40 each as control and experimental groups, and T. canis ova containing infective larvae were given to mice in the latter group to form visceral larva migrans. Blood samples were taken from 5 infected and 5 control mice on days 25, 30, 35, 40, 45, 50, 55, and 60 after infection. After bleeding, the mice were necropsied. Slides were prepared from their brain tissues and examined for visceral larva migrans. Following this procedure, their guts were also examined for intestinal parasites. Protein bands of excretory/secretory antigens of 2nd stage larvae of Toxocara canis were determined by using SDS-PAGE. Sera from the mice were tested by Western blotting and results were compared to the protein bands obtained by SDS-PAGE to determine specific bands. Specific protein bands for visceral larva migrans were determined as 24, 28, and 48 kDa according to our test results.  相似文献   

4.
Groups of mice were vaccinated twice with soluble extracts of embryonated eggs, females or males of Toxocara canis, or horse serum, and infected with 2,000 homologous embryonated eggs. Recovery of larvae on the fifth day by digestion of mesenteric lymph nodes, liver, lung, brain, and carcass revealed a slight but nonsignificant protection elicited by the parasite materials. Other groups were immunized by homologous infections. A single, 200-day-old infection increased importantly the number of larvae resulting from a challenge, possibly by inducing an immunosuppression in the host. Two infections given within 11 months protected partially against the larvae of a challenge, particularly by trapping the parasites in the liver. Transfer of mesenteric lymph node cells from twice infected mice reduced the total number of parasites, and the liver and lung parasitism of a challenge in the recipients, whereas transfer of serum decreased the total number of parasites and the brain and carcass parasitism. The combination of cells and serum acted synergistically in lungs and brain but antagonistically in liver and carcass.  相似文献   

5.
Eleven rabbits were infected with 10 embryonated eggs of Toxocara vitulorum per g body weight on Days 0, 35 and 72. Embryonated eggs and larvae were enumerated in feces on Days 1-3 after each infection. Two rabbits were killed and larvae were enumerated in small intestine, liver, lungs, skeletal muscles, heart, kidney, brain, eye, uterus, and mammary glands on Days 5, 15, 30, 65 and 101. Serum was obtained on Days 0, 5, 15, 30, 42, 50, 65, 78, 86 and 101 to perform enzyme-linked immunosorbent assays (ELISAs) and Western blots against an extract of embryonated eggs. Between 4 and 10% of the administered parasites, almost all embryonated eggs, were found in the feces after the first or second infection, but 32% (27% of them larvae) after the third. Yields of tissue parasites were 4.1% of the administered dose on Day 5, 2% on Day 15, and 0.8% on Day 30 of the first infection, 0.1% on Day 30 of the second infection, and 0.06% on Day 30 of the third. Larvae were found only in liver, lungs and muscle, including heart. Larva content declined steadily in liver and lungs from Day 5 to 30 of the first infection, was absent in the liver at Day 30 of the second, and in both organs at Day 30 of the third. Muscle larva content increased from Day 15 to 30 of the first infection, and persisted throughout the third infection. Production of IgM antibody was minimal, IgG and the sum of IgMGA antibodies increased slightly or moderately after the first and second infections, but dramatically after the third. Western blots revealed the first antigens (12) by Day 15 of the first infection. Their total number increased with time and number of infections, but some antigens disappeared, whereas new antigens appeared in the course of the observations. Four antigens (32,500-41,000 mol.wt.) may be related to protection. Comparison of the Western blot patterns of two rabbits showed differences in the antigens, recognizable for each rabbit.  相似文献   

6.
The ability of Trichinella spiralis larvae to survive at subfreezing temperatures encysted in the musculature of wild carnivorous mammals was assessed by evaluating motility and infectivity (to rodents) of trichinae at various intervals after storage in frozen skeletal muscle. Fifty to 60% of the larvae in grizzly bear meat were alive after storage for 27 months at -6.5 to -20 C, and 30% to 50% were still alive at 34 months. However, none survived for 38 months, on the basis of infectivity in mice and larval motility. Trichinella larvae survived up to 4 months in frozen (-6.5 to -20 C) wolverine tissue. Viable larvae were not recovered from mountain lion or fisher muscle frozen for 1 month. The effect of postslaughter processing on Trichinella larvae encysted in bear meat was evaluated by use of a similar bioassay procedure. Viability of larvae recovered from black bear meat that had been processed into ham or jerky was not affected by dry curing with a commercial salt mixture. Trichinae from both preparations induced infections in mice (58 to 90 larvae/g of tissue). However, a combination of curing and smoking was consistently lethal to encysted larvae. Viable trichinae were not recovered from ground bear meat preparations (pepperoni, salami, or sausage) processed according to commercial standards.  相似文献   

7.
One thousand one hundred and fifty-one free-living foxes (Vulpes vulpes) from different parts of Sweden were investigated. Totally 19.6 % were infected with trichinella. Infected foxes were found in all counties except the geographically isolated island of Gotland. In the different counties 6–48 % of investigated foxes were infected.Trichinella was more common in old foxes than in young, 40 % and 11 %, respectively. Regarding male and female, however, the frequency was the same.The number of trichinella per g of muscle varied between 0.05 and 200. Less than 1.0 trichinella larva per g muscle was established in 27.3 % of the foxes, between 1 and 49.9 trichinella larvae in 69.3 % and 50 or more trichinella larvae per g muscle in 3.4 % of the foxes. The number of trichinella larvae per infected fox was roughly the same in both sexes as well as in different age groups.The potential danger of transmitting trichinella from foxes and other carnivores to swine and man is pointed out.The high frequency of trichinella in foxes, 19.6 %, was compared to the very low frequency in swine, 0.00018 %, and in man, 0.00003 %.  相似文献   

8.
A Trichinella murrelli infection in a domestic dog in the United States   总被引：1，自引：0，他引：1  
Trichinella murrelli infection was diagnosed in a naturally infected Beagle bitch from VA, USA, where encapsulated larvae were found in histological sections of several skeletal muscles. A laboratory reared dog fed infected muscles resulted in viable muscle larvae that were subsequently infective to Swiss-Webster mice. Multiplex PCR using larvae from the experimentally infected dog demonstrated two distinct bands migrating at 127 bp and 316 bp which together are diagnostic for T. murrelli; the isolate was assigned the ISS code: ISS1608 by the International Trichinella Reference Centre. This is the first report of T. murrelli infection in a companion animal.  相似文献   

9.
The effect of fenbendazole therapy was studied in six dogs fed 10,000 embryonated Toxocara canis eggs. At 47 days after they were fed T canis, four dogs were given fenbendazole in two divided doses totaling 50 mg/kg of body weight each day for 14 days. Two infected dogs were not given fenbendazole. All dogs were necropsied at the end of treatment and the foci were counted in the lungs; their skeletal muscles were digested in 1% trypsin for the recovery of larvae. The T canis larvae were not recovered from the skeletal muscle of the four infected dogs treated with fenbendazole; 15 and 42 larvae/100 g of skeletal muscle were recovered from the two nonmedicated infeected dogs. The number of grossly visible foci on surfaces of lungs in treated dogs was markedly less than in the nonmedicated infected dogs. The results indicate that fenbendazole might be effective in preventing prenatal infection in dogs.  相似文献   

10.
Fan CK  Lin YH  Du WY  Su KE 《Veterinary parasitology》2003,113(2):145-155
Infectivity and pathogenicity to mice of embryonated eggs of Toxocara canis, that had been maintained in 2% formalin for 14 months at 4 degrees C, were evaluated by immunological and pathological assessment at 1, 4, 8, 12, 16, 20, 24, 28, 42 and 67 weeks post-infection (WPI). On each date, three infected mice and two age-matched uninfected mice were sacrificed for serum collection and histological processing of the liver, lungs, musculature, and brain. Infectivity assessment by enzyme-linked immunosorbent assay (ELISA) revealed that the overall immunological pattern of infected mice tended to be towards the Th2 type response. Serum IgG1 antibody titers in infected mice were significantly higher than that of the uninfected control mice throughout the trial (P<0.05). On the other hand, no significant difference in titers of IgG3 antibody, an indicator for the Th1 type response, was observed between the infected and control mice, except at eight WPI (P<0.05). Pathogenicity was assessed semiquantitatively by comparing the mean number or diameter of inflammatory foci as well as histopathological changes in the liver, musculature, brain, or lungs of the infected mice and the control mice. Each hematoxylin and eosin (H&E) stained tissue section slide was examined under 100x magnification and 15 random fields were counted. Degree of inflammatory injury among the four organs was scored and categorized into four levels: normal (0), mild (1+), moderate (2+), and severe (3+). An index of inflammatory injury (mean score of experimental group/mean score of 10 control groups of 20 uninfected mice) of 2-3 is considered as moderate to severe, 1-2 as mild to moderate, and 0-1 as normal to mild. Histopathological changes were moderate to severe in the liver and lungs, mild to moderate in the musculature, and only normal to mild in the brain throughout the trial. It is noteworthy that apocrine-like change in epithelial cells of the bile duct was observed in most of the infected mice from eight WPI onward. Furthermore, larvae trapped by organized granulomas were found in soft tissue near the musculature at 12, 20, and 28 WPI. Altogether, not only were the infectivity and pathogenicity of the 14-month-cultured T. canis embryonated eggs retained, the hatched larvae were also capable of eliciting some special pathological changes in the murine host.  相似文献   

11.
Acquired immunity develops against Toxocara canis infection in mice, and NIH mice are more immunoresponsive than CD1 mice. Twice infected NIH female mice showed 27% reduction in the total larval recoveries compared with non-sensitized controls. Twice-infected NIH male, and CD1 (both sexes) mice showed a negligible reduction in the total recoveries, though a significant (P less than 0.05) number of larvae were retained in the liver compared with the non-sensitized controls. All twice-infected mice showed a significant reduction in the number of larvae recovered from the brain compared with once-infected mice. Vaccination using ultraviolet irradiated embryonated eggs gave the best protection against reinfection. Excretory/secretory antigen afforded less protection, whilst whole adult worm vaccine and whole L2 culture vaccine gave no protection. Vaccinated mice had a higher 'free:penetrating ratio' of larvae in their intestine than similarly challenged but non-vaccinated mice. When the ileum was examined histologically 9 h post-infection, an inflammatory reaction was seen around the penetrating larvae in the sensitized and vaccinated mice but not in untreated controls, suggesting a role played by the intestine in the resistance against T. canis infection in mice.  相似文献   

12.
Following oral infection of NIH mice with Toxocara canis embryonated eggs the L2 pass the visceral phase of migration during the first week of infection. Larvae reach the liver and lungs and peak in number in these organs 2 and 3 days after infection, respectively. Larvae are then dispersed throughout the body and enter the myotropic—neurotropic phase by the 7th day of infection. Larvae injected directly into the brain are capable of migrating into the viscera and musculature. Considerable pathology occurs due to larval migrations, especially through the liver and lungs, and both acute and chronic disease are recorded. Studies of infections extending over a year show that the number of recoverable larvae declines gradually with periods of stable populations.On Days 3, 4 and 5 after infection, larvae were demonstrable in the faeces of infected mice. Prenatal infection was observed in a third of the offspring of mice infected the same day as conception.  相似文献   

13.
To evaluate the interdependence between pathological changes and the level of infection the behaviour of Toxocara canis larvae in the host, the course of the disease as well as quality and quantity of histological changes were investigated after experimental infection with 1,000, 500, 250, and 125 larvae respectively. The main places where the larvae of Toxocara canis were found at any time after infection were musculature and brain. Regardless of the level of infection the absolute and relative number of larvae in the brain increased linearly, and parallel decreased in musculature. After the 60th day post infection the mice infected with 1,000 larvae showed compulsive movements, disturbance of equilibrium and paralysis of the hindlegs. The mice infected with 500 larvae showed similar symptoms 30 to 40 days later. Mice with weaker infections only showed slight disturbances of the general condition at the end of the trials. In the brain of all animals infected with larvae of Toxocara canis inflammatory reactions were found. Severe destructive changes in the nervous substance together with clinical symptoms were seen only in higher infected mice.  相似文献   

14.
Migration and distribution of Toxocara canis larvae in the tissues of Japanese quail, infected orally with 5 X 10(3) infective eggs, and the establishment of patent infection from the quails to the definitive host, were studied. Larval yield at necropsy from various tissues and organs of quail varied from 4.72 to 7.54% of the infective eggs inoculated within the period 1-60 days post-infection (PI). The total number of larvae recovered on different days showed a gradual increase. The percent inoculum recovered at necropsy was highest on Day 60. Most of the larvae were found in the liver throughout the period and only a few migrated to other tissues, such as lung, heart, muscle and brain. The establishment of patent infections in the definitive host was studied by feeding the 15-day infected livers of Japanese quail (400 larvae) to Toxocara-free pups. Eggs first appeared in the faeces 38 days post-infection, the mean worm burden at necropsy was 87 and the percentage of infection established was 21.75%. Thus the role of Japanese quail as a paratenic host of T. canis is established.  相似文献   

15.
This experiment was conducted to explore the intervention effect and mechanism on insulin resistance (IR) mice of total flavonoids from Melastoma dodecandrum Lour.(TFMD).The model of IR mice was established by intragastric administration of high-fat emulsion,while 600,300 and 150 mg/kg TFMD were administered once daily for 30 days.After the end of the experiment the mices' fasting blood glucose (FBG),fasting serum insulin (FINS),serum total cholesterol(TC),triglyceride (TG),high density lipoprotein(HDL) were determined.The mRNA expression level of liver insulin receptor(InsR),fat peroxisome proliferator-activated receptor-γ(PPAR-γ),and glucose transporter 4 gene (GLUT4) in skeletal muscle were detected by Real-time quantative PCR,and the protein levels were detected by immunohistoche mical method.The results showed that TDMF could reduce the body weight of IR mice,decrease the level of serum FBG,FINS and HOMA-IR,increase the level of ISI,decrease the content of serum TG,TC and LDL,and increase the content of HDL(P<0.01,P<0.05);And the mRNA expression of INSR,PPAR-γ in liver and GLUT4 in skeletal muscle of IR mice were increased(P<0.01,P<0.05),and the protein expression level of InsR,PPAR-γ in liver and GLUT4 in skeletal muscle of IR mice were increased(P<0.01,P<0.05).The results confirmed that the TFMD could relieve experimental insulin resistance in mice,and the activity was related to the regulation of glucose and lipid metabolism and the enhancement of insulin sensitivity.  相似文献   

16.
本研究旨在探讨地菍总黄酮（TFMD）对胰岛素抵抗（IR）小鼠的干预作用及其机制。试验以灌胃高脂乳剂建立胰岛素抵抗小鼠模型，同时灌胃给予地菍总黄酮混悬液（高剂量（600 mg/kg）、中剂量（300 mg/kg）及低剂量（150 mg/kg））进行治疗，治疗周期为30 d。试验结束后测定小鼠血清中空腹血清胰岛素（FINS）、空腹血糖（FBG）、胰岛素抵抗指数（HOMA-IR）、胰岛素敏感指数（ISI）、血清甘油三酯（TG）、总胆固醇（TC）、低密度脂蛋白（LDL）及高密度脂蛋白（HDL）水平；利用实时荧光定量PCR法检测各组小鼠肝脏中胰岛素受体（InsR）、过氧化物酶体增殖物激活受体-γ（PPAR-γ）及骨骼肌中葡萄糖转运体4（GLUT4）的mRNA表达水平；利用免疫组化技术检测各组小鼠肝脏中InsR、PPAR-γ和骨骼肌中GLUT4的蛋白表达水平。结果显示，与模型组相比，地菍总黄酮能降低IR小鼠的体重，降低血清FBG、FINS及HOMA-IR水平，升高ISI水平（P<0.01，P<0.05）；降低血清TG、TC及LDL含量，升高HDL含量（P<0.01，P<0.05）；同时提高IR小鼠肝脏中InsR、PPAR-γ及骨骼肌中GLUT4的mRNA表达量，提高小鼠肝脏InsR、PPAR-γ及骨骼肌中GLUT4的蛋白表达水平（P<0.01，P<0.05）。以上试验结果证实，地菍总黄酮能有效缓解小鼠试验性胰岛素抵抗症状，该活性与调节糖脂代谢、增强胰岛素敏感性有关。  相似文献   

17.
Paranatal transmission of Toxocara canis infection could be prevented in pups if an effective drug were administered to pregnant bitches. This drug also could eliminate the larvae in dogs that have been experimentally infected repeatedly to produce protective immunity. For these reasons, we assayed the effect of 2 doses of levamisole hydrochloride or ivermectin on T canis larvae. Mice (5 groups) were infected with 1,000 infective T canis larvae and then treated with 2 different dosages of levamisole hydrochloride (6 mg/kg or 12 mg/kg, given subcutaneously), 2 different dosages of ivermectin (0.2 mg/kg or 0.4 mg/kg, given IM) or 0.15M NaCl (given subcutaneously) once a day from days 15 to 28 of infection. On day 33 of infection, the parasites in liver, lungs, brain, and carcass were obtained and compared between groups. The smaller dosage of levamisole hydrochloride (6 mg/kg) significantly decreased only carcass parasitism to 17% of that in the controls, but did not affect significantly the total parasite load. The larger dosage of levamisole hydrochloride (12 mg/kg) decreased the infection in all organs, but particularly in carcass and brain; total parasitism was only 36% of that in the controls. The smaller dosage of ivermectin (0.2 mg/kg) significantly increased the number of larvae in the lungs to 550% of that in the controls, but it did not significantly affect the total parasite load. The larger dosage of ivermectin (0.4 mg/kg) significantly decreased only brain parasitism, but liver and total parasitism were decreased to 40% and 57%, respectively, compared with that in the controls.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

18.
Concentrations of total, free, and esterified carnitine were determined in plasma, liver, and skeletal muscle from cats with idiopathic hepatic lipidosis and compared with values from healthy cats. The mean concentrations of plasma, liver, and skeletal muscle total carnitine; plasma and skeletal muscle free carnitine; and plasma and liver esterified carnitine were greater (P less than 0.05) in cats with idiopathic hepatic lipidosis than in control cats. The mean for the ratio of free/total carnitine in plasma and liver was lower (P less than 0.05) in cats with idiopathic hepatic lipidosis than in control cats. These data suggest that carnitine deficiency does not contribute to the pathogenesis of feline idiopathic hepatic lipidosis.  相似文献   

19.
During susceptibility studies of non-specific hosts, three merino sheep were infected with 3000, 5000 or 7000 Trichinella spiralis larvae by gavage. Clinical, physiological and serological parameters were assessed during the experiment. On the 152nd day p.i., animals were necropsied and, using artificial digestion methods, numbers of Trichinella larvae in muscle tissues were determined. The most infected parts were masseters with 3122 larvae g-1 muscle, 5526 larvae g-1 muscle and 4058 larvae g-1 muscle and diaphragms with 2778 larvae g-1 muscle, 2725 larvae g-1 muscle and 2320 larvae g-1 muscle, for the 3000, 5000 and 7000 infection levels, respectively. A positive correlation between infective rate and circulating antibodies was observed using ELISA and latex agglutination (LA) test methods. Trichinella larvae from sheep applied by gavage to ICR mice developed to the muscle stage. No significant changes were found in the clinical and physiological parameters of infected animals. Our results confirm the high susceptibility of merino sheep to T. spiralis infection.  相似文献   

20.
为了研究PCR检测感染小鼠血液中旋毛虫DNA的敏感性,应用旋毛虫1.6 kb重复序列为扩增靶序列对旋毛虫(T1)、乡土旋毛虫(T2)、布氏旋毛虫(T3)、伪旋毛虫(T4)和南方旋毛虫(T7)肌幼虫DNA进行PCR扩增,并检测小鼠感染20、100、300条T1肌幼虫后不同时间的外周血.结果表明,T1、T4和T7肌幼虫可扩增出特异性目的条带(510 bp),而T2和T3无扩增产物;1、0.04和0.02条T1、T4和T7肌幼虫均能扩增到清晰的目的条带(510 bp).20条幼虫感染小鼠后5 d～6 d,PCR阳性率均为7.69%;100条幼虫感染小鼠后5 d～12 d可检出旋毛虫DNA,其中感染后5 d～7 d的阳性率分别为30.77%、38.46%及30.77%;300条幼虫感染小鼠后5 d～15 d可检出旋毛虫DNA,感染后7 d的阳性率为61.54%,感染后6 d与8 d～10 d的阳性率均为53.85%. 3组旋毛虫感染小鼠PCR阳性率间的差异有统计学意义(p<0.01),PCR阳性率随感染剂量的增加而升高(p<0.01),100条与300条感染小鼠感染后不同时间的PCR阳性率与检测时间有相关性(p<0.01).以上实验结果表明PCR检测感染小鼠血液中旋毛虫DNA的敏感性与感染程度和检测时间有关,对感染早期旋毛虫抗体阴性宿主有一定诊断价值.  相似文献   

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