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1.
Half a million sporocysts of Sarcocystis levinei obtained from experimentally infected dogs were fed to a buffalo calf, and sarcocysts of this species were recovered from its oesophageal muscles when the animal was killed on the 62nd day of inoculation, thus establishing a buffalo-dog-buffalo cycle.  相似文献   

2.
The development of the parasite was studied in 48 sheep killed between 188 and 1132 days after experimental inoculation with Sarcocystis medusiformis sporocysts from cats. Immature sarcocysts were present at 188 days post inoculation (d.p.i.). At 331 d.p.i. macroscopic sarcocysts with an elongate fusiform appearance were seen in the laryngeal, abdominal and diaphragm musculature. The largest cyst measured 2 mm in length by 0.5 mm in width at 331 d.p.i.; histologically they contained metrocytes at the periphery of the cyst with more densely staining merozoites in the central region. By 443 d.p.i. typical 'thin' cysts 2-3.5 mm in length were seen in the flank and external thoracic muscles. By 765 d.p.i. sarcocysts were 5 mm in length. The ultrastructure of the cyst wall of these cysts resembled that of S. medusiformis. At 1132 d.p.i. sarcocysts measured 4 mm X 0.5 mm.  相似文献   

3.
Eighteen calves were orally inoculated with either 200,000 or 225,000 sporocysts of Sarcocystis cruzi. Eight goats were orally inoculated with 20,000 sporocysts of S capracanis. Calves and goats were euthanatized at various times after inoculation, and portions of their right and left biceps femoris, right and left longissimus dorsi, myocardium, and tongue were frozen at -150 C in precooled isopentane and stored at -70 C. Frozen sections of these muscles were stained with hematoxylin and eosin, modified Gomori's trichrome, nonspecific esterase, diphosphopyridine nucleotide tetrazolium reductase, and adenosinetriphosphatase at pH 10.4 and 4.6. Muscle from the same locations was fixed in 10% neutral buffered formalin, processed for paraffin embedding, sectioned, and stained with hematoxylin and eosin. Microscopic examination of both calf and goat tissue indicated that both type I and type II muscle fibers were equally infected and that infected myofibers showed no apparent damage other than displacement by sarcocysts. Occasionally, muscle fibers within the muscle spindles contained sarcocysts.  相似文献   

4.
Sarcocystosis was studied in 37 sheep after oral inoculation with 10(4)-5 x 10(7) sporocysts of Sarcocystis tenella from canine feces. Two sheep inoculated with 2.5 x 10(7) and 5 x 10(7) sporocysts became moribund 16 and 19 days post-inoculation (DPI), respectively, due to occlusion of arteries of gut and mesentery by first generation meronts. Sheep inoculated with 10(7) sporocysts remained clinically normal until 21 DPI and those inoculated with 10(5)-10(6) became ill 24-28 DPI due to anemia coincident with maturation of second generation meronts. Inflammation, hepatitis and myocarditis were the main lesions of acute and subacute ovine sarcocystosis. Inflammation began to subside by the time (75 DPI) sarcocysts matured. Sarcocystis-induced encephalitis was distinguished from naturally occurring myelomalacia in sheep caused by an unidentified sporozoan.  相似文献   

5.
Fifteen gamma-interferon gene knockout mice were each orally inoculated with 5 x 10(3) Sarcocystis sporocysts derived from Virginia opossums (Didelphis virginiana) fed nine-banded armadillo (Dasypus novemcinctus) muscle containing sarcocysts. Three mice were inoculated with similarly obtained homogenates, but in which no sporocysts were detected. Mouse M8 was pregnant when inoculated and gave birth during the trial. Fifteen of 15 (100%) mice inoculated with sporocysts developed neurologic signs and/or died by day 30 d.p.i. One of 3 (33.3%) mice inoculated with homogenates in which no sporocysts were detected developed clinical signs and died at 34 d.p.i. All young of mouse M8 had maternally acquired antibodies to Sarcocystis neurona, but none developed clinical neurologic signs or had protozoal parasites in their tissues. All brains from mice that developed clinical signs contained merozoites that reacted positively to S. neurona antibodies using immunohistochemical techniques. Evidence from this study further supports the nine-banded armadillo being an intermediate host of S. neurona.  相似文献   

6.
Young calves were inoculated with respiratory syncytial virus (RSV) intranasally or by a combined intranasal and intratracheal route and were killed between postinoculation (initial) days (PID) 1 and 14. Viral antigens were detected by immunofluorescence in nasopharyngeal cells from calves killed between PID 2 and 10. Evidence of infection of the trachea and lungs with RSV was obtained by immunofluorescence and virus isolation in calves inoculated by the combined route, but not in calves inoculated intranasally. Within the lungs, RSV antigens were observed in epithelial cells of bronchioli and alveoli. The only virus detected in inoculated calves was RSV. With the exception of 1 calf, bacteria or mycoplasmas were not isolated from the lower respiratory tracts of inoculated calves. Antibody to RSV was not detected in calves killed up to PID 5, but 4 of 5 colostrum-deprived calves killed between PID 10 and 13 had antibodies to RSV. Preexisting, maternally derived antibody to RSV did not protect the calves from infection. Seemingly, the clinical signs of pneumonia and pathologic lesions observed in inoculated calves were caused by RSV infection.  相似文献   

7.
Equine protozoal myeloencephalitis (EPM) is a serious neurologic disease of horses in the Americas and Sarcocystis neurona is the most common etiologic agent. The distribution of S. neurona infections follows the geographical distributions of its definitive hosts, opossums (Didelphis virginiana, Didelphis albiventris). Recently, cats and skunks were reported as experimental and armadillos as natural intermediate hosts of S. neurona. In the present report, raccoons (Procyon lotor) were identified as a natural intermediate host of S. neurona. Two laboratory-raised opossums were found to shed S. neurona-like sporocysts after ingesting tongues of naturally-infected raccoons. Interferon-gamma gene knockout (KO) mice fed raccoon-opossum-derived sporocysts developed neurologic signs. S. neurona was identified immunohistochemically in tissues of KO mice fed sporocysts and the parasite was isolated in cell cultures inoculated with infected KO mouse tissues. The DNA obtained from the tongue of a naturally-infected raccoon, brains of KO mice that had neurological signs, and from the organisms recovered in cell cultures inoculated with brains of neurologic KO mice, corresponded to that of S. neurona. Two raccoons fed mature S. neurona sarcocysts did not shed sporocysts in their feces, indicating raccoons are not likely to be its definitive host. Two raccoons fed sporocysts from opossum feces developed clinical illness and S. neurona-associated encephalomyelitis was found in raccoons killed 14 and 22 days after feeding sporocysts; schizonts and merozoites were seen in encephalitic lesions.  相似文献   

8.
Four hundred fifty day-old Hubbard broiler chicks were subdivided into 15 groups of 30 chicks each. Six groups of chicks received 0.5 ml of broth culture containing 5 x 10(6) colony-forming units (CFU) of Salmonella enteritidis (SE) phage types (PTs) 4, 8, and 23 by crop gavage. Similarly, six other groups received 0.5 ml containing 5 x 10(8) CFU of SE. One group was inoculated with 0.5 ml containing 5 x 10(6) CFU of Salmonella pullorum, and another group received 0.5 ml containing 5 x 10(8) CFU of S. pullorum. A group of 30 chicks were kept as uninoculated controls. Chicks were observed daily for clinical signs and mortality. All birds were weighed at 7, 14, and 21 days postinoculation 21 (DPI). Four chicks were randomly selected from each treatment group, euthanatized, and necropsied at 7 and 14 DPI. Gross lesions were recorded and selected tissues were collected for histopathology. The higher rates of illness and mortality were observed in chicks inoculated with 5 x 10(6) and 5 x 10(8) CFU of S. pullorum, followed by SE PT4 of human origin and SE PT4 of chicken origin. Moderate to high mortality was observed in chicks inoculated with the higher dose of SE isolates that belonged to PT8 and one SE of PT23. Variable mortality was evident in groups inoculated with the lower dose of salmonella. The most consistent gross and histopathologic changes, including fibrinous pericarditis and perihepatitis, were seen in the dead birds from various treatment groups. The lower mean body weights were present in all treatment groups compared with uninoculated controls. No illness or mortality was observed in uninoculated control groups.  相似文献   

9.
The DB2 calf strain of bovine coronavirus (BCV) was used to inoculate 1-day-old specific-pathogen-free (SPF) turkey poults in three trials. In all trials, the birds developed clinical signs of enteritis at 48-72 hr postinoculation. Birds euthanatized at 3, 5, and 7 days postinoculation (DPI) had flaccid, pale intestines with watery contents, and the ceca were markedly enlarged with frothy contents. Coronavirus particles were detected by immune electron microscopy with BCV antibodies from the intestinal contents of birds killed at 3, 5, 7, and 12 DPI. Body weights of inoculated poults killed at 3, 5, and 7 DPI were significantly reduced as compared with controls. Hemagglutinating antibodies were detected in sera of convalescent birds at 12 DPI. However, experimental inoculation of 1-day-old SPF chicks in two trials with the same virus resulted in no clinical signs or macroscopic or microscopic lesions. No coronaviruses were detected from intestinal contents, and there were no significant differences in body weights of inoculated and noninoculated control chicks.  相似文献   

10.
The effect of acute bovine sarcocystosis was studied by correlating in vitro lymphocyte blast transformation studies with morphologic and hematologic changes. Yearling calves inoculated with 900,000 sporocysts (large dose) had decreased responses to phytohemagglutinin and pokeweed mitogen and corresponding morphologic evidence of depletion of both T and B lymphocytes in all lymphoid organs examined during the first 4 weeks. The T-cell depletion was characterized by marked thymic atrophy. In lymph nodes denoting B-cell depletion, there were lymphoid follicular exhaustion and various degrees of follicular loss. Significant change in total circulating lymphocytes was not observed. All animals given this large dose died or were killed (in a moribund state) by 5 weeks after they were inoculated. Changes in mitogen responsiveness were not significant during the 4 weeks after yearling calves were inoculated with 90,000 sporocysts (small dose). The mitogenic effect of phytohemagglutinin was significantly greater than that of the control group during weeks 4 to 18. During this period, morphologic evidence of thymic cortical regeneration occurred. The results indicate that acute sarcocystosis is accompanied by a lymphoid abnormality which could result in immunosuppression, adding to the severity of natural infection.  相似文献   

11.
Sixteen calves and 6 cows were each inoculated with 100 000 infective oocytes of the GT-1 strain of Toxoplasma gondii. Cattle were necropsied between 3 and 287 days post-inoculation (DPI) and their tissues were inoculated into mice or fed to Toxoplasma-free cats for the detection of Toxoplasma in bovine tissues. Ten to 10 000-fold more T. gondii were recovered from small intestine and mesenteric lymph nodes of calves at 3 and 6 DPI than from lungs and liver, and the number of T. gondii in bovine tissues was reduced 1000-fold between 6 and 8 DPI. By using the pepsin digestion technique, or feeding tissues to Toxoplasma-free cats, it was demonstrated that T. gondii encysted in bovine tissues as early as 11 DPI and persisted as late as 287 DPI. More Toxoplasma gondii cysts occurred in livers than in any other bovine tissue. Of the 6 cows inoculated at 95–155 days after breeding, 5 delivered normal calves and T. gondii was isolated from only one of these calves. One cow was barren. Toxoplasma gondii was not isolated either by mouse inoculation or by feeding cats tissues from 2 cows killed 132 and 190 DPI. Toxoplasma gondii was not isolated in mice inoculated with tissues of cows killed 98 and 109 DPI, but cats fed on bovine tissues shed T. gondii oocysts. The organism, however, was isolated in mice inoculated with the mesenteric lymph nodes of 1 of the 2 cows killed 162 and 168 DPI, and from the small intestine of the other. Cats fed tissues of these cows later shed T. gondii oocysts.  相似文献   

12.
The influence of the number of sporocysts in the inoculum of Sarcocystis falcatula on the morphology of the sarcocysts has not been reported in the literature. To determine if there is a relationship, different number of sporocysts were inoculated orally into wild-caught cowbirds. After 14 weeks, the cowbirds were euthanised and muscle tissue was examined grossly and by histologic sections. Sarcocysts were compared based on the numbers which developed and their sizes. There was a linear increase in the number of sarcocysts as the size of the inoculum increased, however, the size of the sarcocysts became smaller with the increase in number of sporocysts inoculated.  相似文献   

13.
Newborn Holstein male calves were purchased within 3 days after birth and were removed from the local farms to the Dixon Springs Agricultural Research Center. They were hand-fed for 7 weeks and then weaned to a prepared feed. Eight groups, each of 4 calves, were housed in separate pens. In each of 4 pens (pens 2 to 5), 1 calf was inoculated with sporulated oocysts of Eimeria bovis (and was not medicated); 1 calf was inoculated and given feed with added monensin at the dosage level of 10 g/906 kg of feed; and 2 calves were inoculated and given medicated feed with added monensin at the dosage level of 20 g/906 kg or 30 g/906 kg. In the 4 other pens (6 to 9), the calves were inoculated with E zuernii and otherwise were given feed without or with added monensin as in pens 2 through 5. Another group of 5 calves (all kept in 1 pen), served as noninoculated, nonmedicated controls. At 14 days after inoculations with E bovis, the single calves in each of the 4 pens that were given the nonmedicated feed began to show clinical signs of coccidiosis and discharged increasing numbers of oocysts. The other inoculated calves (given monensin) had fewer clinical signs and discharged fewer oocysts in the feces as the level of medication in the feed increased. The calves inoculated with E zuernii developed only moderately severe infections when compared with those inoculated with E bovis. Inoculated (with E bovis) nonmedicated calves had severe reductions in feed consumption and weight, and 3 of 4 died.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

14.
Five Virginia opossums (Didelphis virginiana) were fed muscles of brown-headed cowbirds (Molothrus ater) containing sarcocysts of Sarcocystis falcatula. Shedding of sporocysts was confirmed in all five opossums by fecal flotation. Counts were conducted daily for 2 weeks and then biweekly until the animals were euthanized and necropsied. The average prepatent period was 9.8 (7-16) days. The number of sporocysts shed varied greatly between the opossums with maximum mean shedding occurring at 71.6 (26-112) days post-infection (DPI). Average sporocyst production was 1480 sporocysts/gram of feces (SPG). Maximum output was 37,000 SPG. Average fecal yield in captivity was 17.5g of feces/day. Opossums shed 25,900 sporocysts/day (average) and a maximum of 647,500 sporocysts/day. All opossums shed sporocysts until time of euthanasia (46-200 DPI). Histologically, numerous sporocysts were present in the lamina propria at necropsy, primarily in the proximal half of the small intestine. Sporocysts were generally in clusters within the lamina propria of the luminal two-thirds of the villi. Sporocysts were found less frequently in the epithelium. No evidence of ongoing gametogony or other development was evident.  相似文献   

15.
Between March and May 1983, tongues and esophagi of 355 adult ewes from Colorado and Idaho were examined for grossly visible sarcocysts. Sarcocysts of Sarcocystis gigantea were found in 35 sheep. Cats fed sarcocysts from these naturally infected sheep shed sporocysts in their feces. Two adult ewes and 12 lambs inoculated with 1,000 to 1,000,000 sporocysts were euthanatized at postinoculation days (PID) 146, 230, 265, 391, 721, and 882, and their tissues were fed to Sarcocystis-free cats. All inoculated sheep remained clinically normal except for mild pyrexia between PID 12 and 18. Sarcocysts first became grossly visible at PID 391 and sarcocysts from sheep first became infectious for cats at PID 230.  相似文献   

16.
Lesions of sarcocystosis were studied in 14 calves necropsied between seven and 110 days after inoculation with 5000 to 25 million sporocysts of Sarcocystis hirsuta from cats. Calves developed fever, anemia, and diarrhea between 11 and 30 days after inoculation. The development of first generation meronts in arteries of small intestine, mesentery, and mesenteric lymph nodes seven to 25 days after inoculation was associated with vascular occlusion and necrosis of associated tissues. The development of second generation meronts in capillaries of striated muscles 15 to 23 days after inoculation was associated with necrosis, edema, and nonsuppurative myositis in heart and other muscles. Sixty-two days after inoculation lesions were reduced to focal areas of granulomatous inflammation around degenerating sarcocysts in striated muscles, but not in the heart.  相似文献   

17.
Ten 75- to 105-day-pregnant does each were inoculated orally within 1 million (2 does), 10,000 (4 does), or 1,000 (4 does) sporocysts of Sarcocystis from coyote feces. Two does not inoculated with sporocysts served as controls. The 2 does inoculated with 1 million sporocysts died from acute sarcocystosis 21 and 22 days after inoculation (DAI), and each had 2 dead fetuses. The 4 does inoculated with 10,000 sporocysts were ill 19 to 33 DAI but survived; 1 aborted at 33 DAI, 1 had a live kid that died within 2 hours of birth 31 DAI, 1 aborted 2 dead fetuses 23 DAI, and 1 had a normal kid 56 DAI. The 4 does inoculated with 1,000 sporocysts and the 2 control does remained clinically normal and had normal kids. Does and their offspring were killed within 24 hours of parturition, and their tissues were examined histologically and microbiologically. Meronts of Sarcocystis were found in the maternal placenta of does inoculated with 1 million sporocysts. Sarcocystis was not found in the placenta, fetuses, or tissues of kids from does inoculated with 10,000 or 1,000 sporocysts, or from control does. Other abortifacient agents were not found in the placenta, fetuses, or kids from any does.  相似文献   

18.
In seven calves we studied experimental invasions by sporocysts of the Sarcocystis cruzi (S. bovicanis) species, isolated from faeces of dingo dogs. Out of clinical changes, an increase in body temperature to 39.6 to 40.5 degrees C is characteristic in the fourth to the eighth week of disease, relaxed attitude of animals, progressive thinning down, anaemia of mucous membranes, diarrhoea and total dehydration. The post-mortem examination completes this observation with generalized hyperplasia of lymphatic nodes to haemorrhagic lymphadenitis and small petechial haematomata on serous coats, particularly on epicardium. Schizonts in the endothelium of capillaries in various organs were evaluated as specific lesions, demonstrated within 26 days from invasion in one calf. From 46 days after invasion we found muscular cysts in three other calves. The titres of sera in all experimental calves obtained with the NFR method are also evaluated as specific. Invaded calves died gradually between the 26th and 59th day, control calves were slaughtered and no sarcocysts were found.  相似文献   

19.
Dysentery lasting 4-8 days was produced in five 4-day-old colostrum-fed calves, after inoculation with an atypical strain of Escherichia coli S102-9; peak excretion of S102-9 occurred during the period of dysentery. Two calves were killed when clinical signs were most severe and bacteria were seen attached to the surfaces of enterocytes in the large intestine; microscopic lesions were seen in these areas. The lesions were identical to those previously reported in a natural outbreak of dysentery in calves, from which E. coli S102-9 was isolated, and to those seen in gnotobiotic calves experimentally infected with S102-9. Reinfection of the three surviving calves 16-20 days later with S102-9 and primary infection of two calves aged 24 and 51 days did not cause dysentery. Four of 659 coliforms isolated from field outbreaks of calf diarrhoea resembled the atypical strain S102-9. These four isolates and S102-9 did not produce heat-stable enterotoxin, but all produced a toxin cytopathic for Vero and HeLa cells. Two of the four isolates were inoculated alone into 4-day-old gnotobiotic calves deprived of colostrum; neither calf developed dysentery but microscopic lesions identical to those produced by S102-9 were detected in the large intestines of both animals.  相似文献   

20.
Clinical sarcocystosis was studied in 37 goats after inoculation with graded doses of sporocysts of Sarcocystis capracanis. Eight uninoculated goats served as controls. Clinical response varied with the dose. Goats inoculated with 10-40 million sporocysts died between 11 and 13 days after inoculation (DAI), from interstitial pneumonia, vasculitis, and necrosis of mesenteric lymph nodes. All goats inoculated with 100,000 or 1 million sporocysts died between 19 and 23 DAI; clinical signs were anorexia, fever (40-41 C), anemia, and weight loss. Four of 4 goats inoculated with 50,000 sporocysts and 1 of 4 inoculated with 10,000 sporocysts died 24, 28, 39, 68, and 61 DAI, respectively. Goats inoculated with 1,000 sporocysts and uninoculated goats remained clinically normal. After day 18 and before day 68, packed cell volume and hemoglobin content decreased to as low as 11% and 3.6 g/dl, respectively. Alanine aminotransferase and lactic dehydrogenase activities were inconsistently increased. Blood urea nitrogen and bilirubin values were increased, reaching as high as 63 mg/dl and 10 mg/dl, respectively. Histologically, thymic atrophy, vasculitis, hepatitis, cholangitis, myocarditis, generalized myositis, and encephalomyelitis were the main microscopic findings. The cause of the anemia in goats that died after day 19 was not determined.  相似文献   

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