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1.
Sepsis with subsequent multisystem organ failure after translocation of bacteria from the gut is a serious risk associated with stress situations. We showed that intestinal bacterial translocation could be one of the pathways for pathogenic Streptococcus suis infections in the pig. In 24 piglets weighing 10-14 kg, free of the extracellular factor (EF+) producing phenotype of S. suis serotype 2, a silicon canula was placed in the proximal jejunum to enable intestinal inoculation and bypassing the upper alimentary tract. The pigs were individually housed. After stress induction in 18 pigs by means of a truck drive in individual cages for 1h, pigs were inoculated through the intestinal canula either with S. suis type 2 EF+ or with growth medium only, and put back in their original housing. The six not transported pigs were also inoculated with the same strain. To prevent oral self-infection, faeces were collected in a bag that was glued around the anus. Clinical and behavioral symptoms were recorded for 72 h post inoculation, and then the animals were sacrificed for pathological and bacteriological examination. In three animals, the inoculation strain was re-isolated from mesenterial lymph nodes and typically affected organs. No S. suis type 2 EF+ was detected by specific polymerase chain reaction (PCR) in any of the tonsil-swabs and -homogenates. We concluded that infection of the organs had taken place after bacterial translocation out of the gut and that the intestinal tract can be a porte d'entree for S. suis type 2 EF+.  相似文献   

2.
Faeces samples from 11 sows and their litters and intestinal contents and scrapings collected from 56 piglets at the time of slaughter were examined for Isospora suis. The findings indicate that oocysts with sporoblasts can be found in faeces samples 24 hours after collection; the prepatent period is about six to nine days and the patent period three to eight days (adjudged under non-experimental conditions); piglets in an infected herd are normally resistant to natural infection for the first three weeks of life. Infection is followed by the development of an active immunity which is not affected by the stress of farrowing.  相似文献   

3.
In two studies carried out in 1974-75 on 10 eight and 25 two week old piglets obtained from a SPF-herd the endoparasitic status was determined. Samples of faeces were examined by microscopy which revealed the presence of Isospora suis, a finding that was quite unexpected in a SPF-herd. During days 17-23 pp. the 25 piglets were not found to excrete oocysts, the earliest findings of oocysts being made 24-35 days p.p. The 10 piglets being kept isolated in individual pens excreted oocysts up until 88 days p.p. The epidemiology of Isospora suis is discussed.  相似文献   

4.
51 gnotobiotic and 63 conventional, one-, or two-days-old piglets were divided into five groups and infected orally either with Isospora suis or rotavirus alone, or with both agents simultaneously or successively with alternative sequences and various intervals. 15 gnotobiotic and 10 conventional piglets served as controls. The development of small intestinal lesions after infection with I. suis was biphasic. The dominant alteration resulting from rotavirus infection was villus atrophy, considerably more pronounced and extensive in gnotobiotic than in conventional piglets. Synergistic action of I. suis and rotavirus was manifested both clinically, and morphologically. This action culminated at the time of the actual, or presumed development of merogony of I. suis, i.e. on DPI 3 to 5. The action develops only if the intestinal epithelium is damaged functionally and morphologically by a preceding rotavirus infection. It is concluded that the synergistic action is based on a competition of rotavirus and I. suis for mature, enzymatically active absorptive cells.  相似文献   

5.
Alkaline phosphatase activity (EC. 3.1.3.1.) in goblet cells was investigated in the small intestine of 16 gnotobiotic piglets infected one day after delivery (DAD) by different rates of oocysts of Isospora suis coccidia. At a high infection rate of I. suis (750,000) the goblet cells were found to be highly positive to alkaline phosphatase on day 3 to day 4 after infection (DAI). In piglets infected by a low infection rate of I. suis oocysts (100,000) the activity of alkaline phosphatase activity in goblet cells was proved on days 4 to 10 after infection. In the first group of piglets, the positive goblet cells prevailed in the middle region of jejunum, with the peak on 4th DAI. It the second group of piglets a marked increase in the alkaline phosphatase activity was recorded in the goblet cells in the posterior part of jejunum on days 4 to 5 after infection and on 10th DAI. No alkaline phosphatase activity in the goblet cells was demonstrated in the control gnotobiotic piglets at the age of two to seven days.  相似文献   

6.
The effect of oral infection of puppies, eight and 10 weeks old, with canine parvovirus of faecal origin was studied. Clinical signs of enteric disease were first apparent at five days after inoculation and persisted during days 6 and 7 after inoculation. The severity of clinical signs varied from transient dullness and anorexia to emesis, dysentery and death. Changes in haematological parameters were first found at day 3 after inoculation when a relative lymphopenia was observed. A profound neutropenia developed in severely affected dogs after the appearance of clinical enteric disease. Post mortem examination revealed thymic atrophy in all dogs killed on day 4 after inoculation. Macroscopic changes in the small intestine were apparent only in animals examined during the phase of severe enteric disease and consisted of thickening, rigidity and congestion of the small intestines. Microscopically there was lymphocytolysis in the thymic cortex and the germinal centres of the lymph nodes from days 2 and 3 after inoculation respectively and this rapidly resulted in depletion of these tissues. There was repopulation of lymph nodes from day 7 after inoculation but significant thymic regeneration was not apparent during the course of this study. In the small intestine, necrosis of crypt epithelium, atrophy of villi and, in some areas, complete collapse of mucosal architecture were found but the extent of these changes varied along the length of the small intestine and between individuals. Regenerative intestinal changes were observed in those animals surviving the acute phase of enteric dysfunction. The variable severity of clinical and enteric lesions, together with the factors which may affect the expression of clinical disease, are discussed.  相似文献   

7.
《Veterinary microbiology》1998,62(4):251-263
The enteric pathogenicity of the ovine C. psittaci serotype 1 isolate S26/3 was assessed using a litter of gnotobiotic piglets. In one group, eight piglets were inoculated at 3 days of age; at 10 days, two of these were re-inoculated. In a second group, six animals were mock-inoculated at 3 days of age as negative controls; subsequently, at 10 days, three of these piglets were inoculated with C. psittaci. The animals were observed for clinical signs, killed and necropsied sequentially between 4 and 17 days of age. At necropsy, specimens were collected for histopathology, immunohistochemistry and serology. Clinical manifestations consisted of sporadic slight softening of faeces observed between 8 and 12 days post inoculation (d.p.i.) in pigs inoculated at 3 days of age and between 4 and 6 d.p.i. in those inoculated at day 10. Histopathological changes were minimal and inconsistent and occurred almost exclusively in the small intestine in pigs of 15 days of age and older; they consisted of a slight shortening of villi, of a small number of tongue-shaped villi and of villous fusions. Immunohistochemistry revealed small numbers of chlamydial inclusions in the small intestinal enterocytes of only five pigs, all killed within 5 d.p.i. An ELISA run on faecal samples collected daily after inoculation from six of the pigs showed that chlamydial antigen was excreted in the faeces. In pigs inoculated at 3 days, chlamydial antigen was detected inconsistently before, and consistently after 9 d.p.i. Pigs inoculated at 10 days excreted antigen consistently after inoculation until the end of their observation period (8 d.p.i.). Infective chlamydiae were detected from the faeces of inoculated piglets using Vero cell cultures. Sera of all pigs were negative for anti-chlamydial antibodies using a complement fixation test. In conclusion, enteric pathogenicity of C. psittaci serotype 1 in a litter of gnotobiotic piglets proved minimal. The results, therefore, indicate that serotype 1 C. psittaci is not likely to cause enteric disease in conventionally reared pigs. Nevertheless, a potential role of swine in the epidemiology of this agent should be considered with regard to spread of Chlamydia to other species.  相似文献   

8.
Twelve sows were inoculated with a low-virulent field strain of swine fever (SF) virus at 40, 65 and 90 days of pregnancy. Transplacental infection occurred in eight sows and these farrowed 88 piglets.Prenatal mortality was highest in litters from sows infected at 40 days after service, and postnatal death was most frequent in litters from sows infected at 65 days. Three sows gave birth to completely infected litters, whereas the five others farrowed litters in which uninfected piglets were found. The later the sows were infected during pregnancy, the more uninfected piglets were born. Twelve piglets recovered from the infection and the percentage of recoveries increased with the stage of pregnancy at which inoculation took place. Twenty-three piglets developed a persistent infection. The earlier infection occurred during pregnancy, the more persistent infections were produced. The persistently infected pigs developed a runting syndrome from about one week after weaning. The clinical signs were more severe in pigs from sows infected at 65 days of pregnancy than in pigs from sows infected at 40 days. A persistent viraemia was present in these pigs with titres ranging between 105.7 and 107.0 plaque forming units/ml of plasma. At autopsy the most pronounced lesions were an atrophy of the thymus, and swollen and pale lymph nodes. Virus antigen was present in lymphoidal, reticulo-endothelial and epithelial tissues.One persistently infected pig survived superinfection with a virulent strain of SF virus for 45 days.  相似文献   

9.
给8头生后3d的哺乳仔猪经口感染猪流行性腹泻病毒(PEDV)“吉”毒株,于感染后18、30、45和96h各扑杀2头,以透射电镜和扫描电镜观察了小肠粘膜上皮细胞及肠系膜淋巴结的超微结构。结果表明,小肠上皮细胞的病变因感染时间不同而有明显差异。上皮细胞的脱落和残留上皮细胞超微结构的破坏,以感染后30h最严重,病毒在这些上皮细胞内的增殖最显著。感染后45h,见有大量新生上皮细胞修补损伤的肠绒毛。感染后96h,小肠绒毛短缩、粗大乃至发生融合。实验仔猪肠系膜淋巴结内巨噬细胞和淋巴细胞的超微结构均遭到破坏,在巨噬细胞内见有PED冠状病毒粒子。  相似文献   

10.
Twenty colostrum-fed piglets from three sows were separated from the sows 24 hours after birth and were randomly divided into five groups of four piglets each. Every piglet in each of four test groups was orally inoculated with about 10(10) colony forming units of Salmonella typhimurium, Salmonella choleraesuis var Kunzendorf or one of two isolates of Klebsiella pneumoniae. One group served as uninoculated controls. Piglets infected with K. pneumoniae developed severe diarrhea beginning about 12 hours after inoculation. They became dehydrated and weak but continued to drink. There were no morphological alterations in intestinal mucosa when piglets were killed and necropsied 48 or 72 hours after inoculation. Klebseilla pneumoniae was isolated from intestine and feces but not from liver or spleen. Piglets inoculated with S. choleraesuis became lethargic and disinterested in food by 24 hours after inoculation. Diarrhea developed by 48 hours after inoculation. Lesions at necropsy 60 or 72 hours postinoculation were subcutaneous edema, mesenteric lymphadenitis, diffuse intestinal superficial mucosal necrosis with villous atrophy, and focal deep ulceration in the ileum. Salmonella choleraesuis was isolated from all segments of intestine and from feces, liver and spleen. Piglets inoculated with S. typhimurium developed a relatively mild diarrheal disease with lesions similar to those with S. choleraesuis infection but less severe. The inoculated organism was recovered from all areas of intestine and from feces, liver and spleen. Serum from infected and control piglets had high (greater than 1:256) agglutinating titres against S. typhimurium but low titres (0 to 1:8) against S. choleraesuis. The agglutinins were assumed to originate from colostral antibodies.  相似文献   

11.
Haemophilus parasuis and Streptococcus suis are both major causes of losses during the nursery period, especially in herds using the segregated early weaning system. In this system, only a few piglets may be colonized with the herd's prevalent systemic strain, which results in infection of naive penmates late in the nursery. In view of these factors, the objectives of this study were: (1) to evaluate the early colonization of piglets with the farm's prevalent systemic strain of H. parasuis and S. suis as an alternative method for disease prevention; and (2) to evaluate 2 different protocols for experimental colonization: direct colonization of piglets and colonization of piglets through nose-to-nose contact with inoculated sows. Haemophilus parasuis and S. suis isolates recovered from diseased nursery pigs were characterized by the rep-PCR technique and the herd's prevalent strains were used for colonization. Piglets in the experimentally colonized groups were inoculated at 5 days of age by the oral route using a spray pump. Sows were colonized at 2 weeks prior to farrowing using a similar protocol. Although both colonization protocols were successful in getting the piglets colonized, direct inoculation of 5-day-old piglets with the herd's systemic strains of H. parasuis and S. suis tended to be more effective in reducing the morbidity and the mortality than the colonization of piglets by nose-to-nose contact with inoculated sows.  相似文献   

12.
The lysosomal activity of enterocytes of the small intestine mucosa was investigated in gnotobiotic and conventional piglets experimentally infected on the first day after birth (DAB) by the oocysts of the coccidia Isospora suis. A method of the proof of beta-D-glucuronidase (EC.3.2.1.31.) activity was used to demonstrate lysosomes. The piglets were infected by different infection doses of oocysts (100,000 oocysts in gnotobiotic piglets and 200,000 oocysts in conventional piglets). In the gnotobiotic infected piglets the activity of beta-D-glucuronidase in enterocyte lysosomes was investigated in the period from day 3 to day 11 after infection (DAI) and in the infected conventional piglets in the period from day 2 to day 10 after infection. Comparing the control piglets, the group of gnotobiotic piglets at the age of 2-5 days and the group of conventional piglets at the age of 4-7 days, the higher activity of beta-D-glucuronidase was demonstrated in the lysosomes of intestinal mucosa enterocytes in the gnotobiotic control piglets (+5.30 of the average density value, Dx). In the infected gnotobiotic and conventional piglets the pattern of beta-D-glucuronidase activity was found to have three stages in the course of this infection. Two stages can be characterized by a great increase in the enzyme activity (DAI 3-9 in gnotobiotic piglets, DAI 2-3 and 7-9 in conventional piglets. The third stage, which is manifest mainly in the conventional infected piglets, is characterized by a marked decrease in the activity of beta-D-glucuronidase, reaching the level of control findings (DAI 10 and mainly 11 in gnotobiotic piglets. DAI 4-6 and 10 in conventional piglets). A topographical picture shows that the two stages of increase and the stage of beta-D-glucuronidase activity decrease occur in the whole small intestine without any predisposition defect of the enzyme in the different sections of the small intestine.  相似文献   

13.
In a large herd of pigs whose piglets suffered from diarrheas coprological examination revealed the great incidence of Isospora suis coccidia in piglets. The first oocysts were found out in seven-day piglets; the highest incidence was observed in twelve-day piglets (65.9%); the time of oocyst elimination (patency) was five to six days. The oocysts appeared in the excrements of piglets two to three days after the diarrhea onset. Individual examinations of piglets demonstrated the correlation between the intensity of clinical signs and the numbers of eliminated oocysts. No oocysts of I. suis were found either in sow excrements or gilt excrements. The I. suis oocysts were diagnosed in the excrements of piglets from first-farrowing sows and in the excrements of piglets from the sows, in the litters of which I. suis had already been demonstrated. Evaluating the therapeutic and preventive effects of the anticoccidic drug amprolium no significant difference was recorded in the I. suis incidence between the medicated group and the control group.  相似文献   

14.
A study of neonatal steatorrhoea in unweaned piglets was carried out in randomly visited herds. Isospora suis and rotavirus were shown to be incriminated in this type of enteric disease and these agents may be considered important enteropathogens for 1-3-week-old piglets in Sweden. More extensive studies of I. suis were undertaken in one large herd. It was found that steatorrhoea may appear in 4-day-old piglets but oocysts were not detected until some days latter. Piglets that were shedding I. suis were not necessarily steatorrhoeic but oocysts were more frequently found in steatorrhoeic faeces than in faeces of normal consistency. The earliest oocyst output was detected at 5 days of age, the average litterage at first appearance being 12.8 +/- 4.0 days. The occurrence of I. suis oocysts in piglets did not correlate with the oocyst output in sows, which almost exclusively included genus Eimeria. Repeated parasitological and virological examination of steatorrhoeic faecal samples from 5-10 litters per herd at an age of 1-3 weeks would be helpful for making a herd diagnosis.  相似文献   

15.
In a group of conventional and gnotobiotic piglets experimentally infected with the Isospora suis coccidia the quantitative presence of acid and neutral mucous substances in the large intestine and the counts of goblet cells in the surface mucosa and in Lieberkühnis crypts (in the following text called just the crypts) were investigated. In conventional piglets infected with the dose of 200,000 oocysts of I. suis coccidia the lowest content of acid mucous substances was recorded from the eighth to tenth day after infection (DAI). A decrease in the activity of neutral mucous substances was somewhat slower. The lowest count of goblet cells was found on DAI 9, especially on the surface mucosa (4.89 to 4.91 goblet cells per 10 enterocytes). There was observed no difference in the piglets infected the first and fifth day after parturition (DAP). Gnotobiotic piglets infected with the dose of 100,000 oocysts of I. suis coccidia on DAP 1 showed the lowest content of mucous substances in the large intestine from the ninth to tenth day after infection. Unlike the conventional piglets, in gnotobiotic piglets there was recorded a decrease in the content of acid and neutral mucous substances. The gnotobiotic piglets had the lowest counts of goblet cells in the surface mucosa (10:4.57) and in the crypts (10:7.71) on DAI 9. As to the quantitative proportions, in the conventional and gnotobiotic piglets neutral mucous substances prevailed on the other days (DAI 3-7 and DAI 11), similarly like on DAI 8. The results of this investigation revealed a functional disease of the large intestine in conventional and gnotobiotic piglets infected experimentally with the Isospora suis coccidia.  相似文献   

16.
Intranasal infection with Bordetella bronchiseptica in gnotobiotic piglets.   总被引：6，自引：0，他引：6  
Nineteen gnotobiotic piglets, four to six days old, from three different litters, were inoculated intranasally on three consecutive days with a pure culture of Bordetella bronchiseptica. Necropsy 10 to 30 days after inoculation revealed atrophic rhinitis lesions in all and pneumonia in 13 (73 per cent)infected piglets. One died of septicaemia two days after inoculation. Agglutinating antibodies were detected in the sera of all piglets necropsied from 17 to 30 days after inoculation. Five control piglets showed no lesions or serological changes.  相似文献   

17.
The involvement of apoptosis in the lymphatic organs of piglets infected with classical swine fever (CSF) virus was investigated. Piglets were inoculated with CSF virus and 3, 5, 7 and 10 days post inoculation (DPI), the thymus, spleen and lymph node were examined. In the thymus cortex, macrophages phagocytizing the nuclear remnants or apoptotic bodies increased after 3 DPI. Thymus atrophy due to the loss of the cortex increased markedly during the observation period. Compact and shrunken nuclei indicating apoptosis were observed in the spleen and lymph node. DNA fragmentation was detected in the nuclei of lymphocytes in the thymus, spleen and lymph nodes, as well as at sites of focal necrosis. Using the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling method, ultrastructural characteristics of apoptosis, i.e. margination of condensed nuclear chromatin, were observed in the lymphatic organs from 2 DPI onward. These results suggest that apoptosis is involved in the pathology of CSF.  相似文献   

18.
Canine parvovirus enteritis 2: Pathogenesis   总被引：1，自引：0，他引：1  
Two groups of puppies, eight and 10 weeks of age, were inoculated orally with canine parvovirus of faecal origin. The patterns of faecal excretion of virus, antibody production and systemic viral localisation following inoculation were studied. Faecal excretion of virus was first apparent at day 3 after inoculation, was present most frequently and in greatest quantity at days 4 to 7 after inoculation and fell sharply thereafter. Serum antibody was first detected at day 5 after inoculation with high titres in all samples from day 7 onwards. Virus isolation from serum samples revealed a non-cell associated viraemia at days 3 and 4 after inoculation. Immunocytochemical examination, using both immunofluorescence and immunoperoxidase techniques, first revealed antigen in the thymic cortex at day 1 after inoculation and in the germinal centres of the lymph nodes and the splenic white pulp from days 2 and 3. Viral antigen was first detected in the intestines at day 4 in individual cells in the proliferative zone of the crypt epithelium. From day 5 onwards, the amount of antigen present in the lymphoid tissue decreased so that by days 7 and 8, only a trace was present. There was widespread specific staining in the small intestinal mucosa at day 6, but little antigen was present by day 7. Virus was present in the bone marrow of some dogs killed at days 5 and 6.  相似文献   

19.
Twelve pigs were inoculated orally with Mycobacterium avium. The doses used were 0.5, 2 or 10 mg daily for 5 days, or 10, 50 or 180 mg once (1 mg = 37 × 106 viable units). Two pigs were used per dose, 1 of which was sacrificed 3 days, the other 28/31 days after the last inoculation (Table 1).Three days after inoculation, M. avium was found in the tonsils and in the intestinal mucosa of all 6 pigs, and in the mesenteric lymph nodes of 4. Viable unit counts for tonsils and intestinal mucosa were highest in pigs inoculated with 180 mg×1 and 10 mg×5. Histopathologically these pigs showed activation of the lymphoid tissue in the tonsils, Peyer patches and mesenteric lymph nodes. Twenty-eight/31 days after inoculation a spreading of the infection had taken place in all pigs, most often to the liver, less frequently to the spleen and the lungs. The kidneys and the musculature were not infected (Table 4). A correlation was apparent between the size of dose and the number of viable organisms in the tissues. Divided doses gave about 10 times higher viable counts than a single dose with the same total number of organisms (Table 5).No gross lesions were found 28/31 days after inoculation. Microscopic granulomatous lesions were found in the tonsils of 6 pigs, in the intestinal mucosa of 4 pigs, in the mandibular and mesenteric lymph nodes of 6 pigs, in the retropharyngeal lymph nodes of 3 pigs, and less frequently in the parotid and hepatic lymph nodes (Table 3).Five of 6 pigs were weakly sensitive to avian tuberculin PPD, 1000 t.u. per dose, when tested 22/25 days after inoculation; 1 of these pigs cross-reacted to human tuberculin (Table 2).  相似文献   

20.
The first day after birth, 22 conventional piglets were experimentally infected with the oocysts of the coccidia of I. suis (infection dose 200,000 oocysts). The activity of 5-nucleotidase (5-ribonucleotide phosphohydrolase, EC.3.1.3.5) and phosphoglucomutase (alpha-D-glucoso-1-phosphate phosphotransferase, EC.5.4.2.2) was densitometrically assessed in the mucosa of the small intestines of these piglets. Enzyme activities were studied in the infected piglets during the 2nd to 10th day after infection. The same histochemical examination was simultaneously performed in the intestinal mucosa of five control conventional piglets at an age of 2-14 days. 5-nucleotidase and phosphoglucomutase were found to have a high density in the mucosa of the small intestine of the control piglets: the high-density locations of these enzymes include, first of all, the supranuclear area of the absorption cells, the microvillous zone of enterocytes and the smooth muscle elements of lamina muscularis mucosae. The experimentally infected piglets showed a marked decline of the density of both enzymes during the infection. The deficit affected, for a transient period, the microvillous zone and the supranuclear region of enterocytes; the musculature of the mucous layer was affected permanently. The inactivity was more protracted in the case phosphoglutamase (especially 5 to 9 days after infection). The density of 5-nucleotidase showed a partial return to the normal already the 7th day after infection, with an interruption of resumption of activity on the 10th day. Resumption of enzyme activity in the lamina muscularis mucosae was not recorded during the infection. In the three locations under study, the density of none of the enzymes did reach parameters comparable with the controls at the end of the trial (10 days after infection).  相似文献   

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