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1.
T Scholz 《Folia parasitologica》1991,38(1):39-55
A part of the life cycle of Proteocephalus neglectus La Rue, 1911, a parasite of trout, starting from release of eggs from mature parasites into water, to the early phase of development in the definitive host, was studied under experimental conditions. Special regard has been paid to development in the intermediate host, copepod Cyclops strenuus. Some oncospheres in eggs kept in water at 5 and 10 degrees C remained infective for 20-25 days. The percentage of infected copepods depended on the length of their contact with parasite eggs. Cestode larvae (cercoscoleces) were formed in the intermediate host on days 8-10 p.i. at the temperatures of 21-22 degrees C, on days 18-21 at 15 degrees C, on days 24-28 at 10 degrees C, and on days 59-65 at 6 degrees C. Most larvae, including infective cercoscoleces, were localized in the cephalothorax of the intermediate host, particularly in its first segment. This localization did not change during their development. The infectivity of cercoscoleces was verified by experimental infection of Salmo gairdneri fry. The development of the cestode in this definitive host was observed for 17 days after infection at 10 degrees C. The finding of P. neglectus cereoscoleces in fish of the families Cottidae and Cyprinidae on day 2 after experimental infection indicates that these larvae can survive for a short time in atypical fish hosts. 相似文献
2.
The development of the nematode Procamallanus saccobranchi Karve, 1952, a parasite in the stomach of the fish Heteropneustes fossilis (Bloch), was studied in Mesocyclops crassus (Fischer) and Mesocyclops leuckarti (Claus). After being ingested by the copepods the nematode first-stage larvae penetrated into the haemocoel of the intermediate host; there they moulted twice (on days 3 and 5 p.i. at 28-30 degrees C) attaining the third, infective stage. The definitive host H. fossilis acquired infection by feeding on copepods harbouring infective-stage larvae; in the stomach of this definitive host, the larvae were observed to undergo two more moults. The third moult occurred on day 13 p.i. and the fourth moult on day 38 p.i. and day 66 p.i. in "male" and "female" larvae, respectively. The larval stages, including the moulting forms are described and illustrated. 相似文献
3.
An experimental infection with the microsporidian Encephalitozoon cuniculi Levaditi, Nicolau et Schoen, 1923 was studied using a model of immunocompetent BALB/c mice and immunodeficient SCID mice. The course of infection after intraperitoneal inoculation of E. cuniculi spores was evaluated using the presence of spores in peritoneal macrophages as a criterion. First significant decrease in the proportion of infected cells was recorded on day 9 post infection (p.i.) in BALB/c mice. From day 14 p.i. no spores were observed in macrophages from BALB/c mice, while the number of infected macrophages from SCID mice increased until the death of the mice. The natural killer (NK) cell activity of mouse splenocytes was compared with the production of interferon gamma (IFN-gamma) by these cells. While in BALB/c mice NK activity peaked on days 9 and 14 p.i., in SCID mice the marked increase of NK activity was recorded close before death of mice, on day 21 p.i. in correlation with the production of IFN-gamma. Production of specific antibodies was demonstrated from day 9 p.i. in sera from BALB/c mice. It is concluded that intraperitoneal infection of SCID mice with spores of E. cuniculi results in the marked increase in the number of peritoneal exudate cells and in the percentage of infected cells close before death of mice. Neither high activity of NK cells nor increased production of IFN-gamma are sufficient for the recovery of SCID mice from an E. cuniculi infection. 相似文献
4.
The pathological picture of the migration phase of C. tenuicollis in pigs is characterized by a haemorrhagia within the liver parenchyma and under the liver surface. The haemorrhagia, which represents a migrational canal, is induced by the destruction of liver sinuses by migrating larvae. Approximately on day 10 p.i. a serofibrinous peritonitis occurs and free cysticerci appear in the exudate. On days 14-16 p.i. the exudative peritonitis may increase. The cysticerci are localized under the serosas or on them. On about day 10 p.i. even the pulmonary form of the disease may occur. On day 13 p.i. the cysticerci are present in the lumen of lung arteries or they migrate out of them. The changes in the lungs and on the pleura, as well as their dynamic changes, are identical with the changes in the liver and on the peritoneum. The period on days 21-24 p.i. is characterized by extensive synechiae of serosas and the cysticerci are firmly attached to the serosas. On day 35 p.i. the connective tissue adhesions persist and many of the cysticerci exhibit dystrophic changes or are dead and often already calcified. The wall of the pseudocyst, in which the cysticercus is situated, consists of the fibrocytes and serosa, and its cavity is not lined with endothelium, as it is the case in C. bovis and C. cellulosae. 相似文献
5.
Histochemical studies on the cysticercus and surrounding tissue reaction were performed at various intervals after experimental infection. It was found that acid mucosubstances and proteins with SH- and SS-groups appeared first in the granulation tissue around the cysticercus (on about day 14 p.i.) and only later (on day 28 p.i.) in the tegument of the cysticercus where they were localized in the rim of microtriches. This envelope consisting of mucosubstances and proteins seems to be identical with the electron-dense substance found on the surface of developing cysticercus during electron-microscopical studies. It is considered to be a mimicry enabling the cysticerci to survive even in an immunologically unfavourable environment. Phospholipids were found in activated fibroblasts and in some cells of macrophage type on days 21 and 30 p.i. and in a large number in subtegumental cells of cysticercus on days 28-34 p.i. This phenomenon seems to be correlated with the increased activity of subtegumental cells of the larva in this period. In morphologically fully differentiated cysticerci, the reaction for phospholipids in subtegumental cells and distal cytoplasm was only feebly positive. Phospholipids were not detected in the rim of microtriches at any time after infection. 相似文献
6.
After subcutaneous injection of T. saginata oncospheres, a slight swelling is visible at the site of injection first after 13 days. Conspicuous projecting nodes appear after 3-4 weeks. Histological examinations of the site of injection revealed the following changes: On days 3 and 4 p.i.--edema, focal necrosis and haemorrhage, exudation of leukocytes, activation of monocytes and fibroblasts. On day 7 p.i.--in addition to edema and foci of eosinophiles, a striking activation of monocytes and fibroblasts, focal accumulation of macrophages, proliferation of blood capillaries and formation of collagen. On day 10 p.i.--eosinophiles and light macrophages around the larvae, fibroplastic granulation tissue at the periphery and collagenous connective tissue abundant. Hyperplasia of lymphoid tissue starts to appear at this time. On days 13-14 p.i.--a large amount of newly formed connective tissue in granulation tissue, diffuse infiltration of eosinophiles and hyperplasia of lymphatic tissue. On days 19-34 p.i.--haemorrhage around the cysticerci, activation of macrophages, phagocytizing erythrocytes. Endothelia of blood capillaries proliferate; lymphatic follicles are formed at the periphery of nodular affection which appears after inoculation of oncospheres. On day 34 p.i.--distinct formation of a pseudocyst. At the period from 53th to 61st day after injection, there is a mature collagenous connective tissue among the cysts, but still strongly infiltrated with cells. Clusters of siderophages are visible in connective tissue septa between the cysts. 相似文献
7.
The concurrent infection with larvae of Trichinella spiralis and eggs of Toxascaris leonina was studied under various conditions using 75 male white mice. The changes in content of eosinophilic leucocytes in the blood, as well as the total number and distribution of larvae of both parasites in different body tissues were demonstrated. The primary infection with Toxascaris leonina caused an increase in the number of eosinophilic leucocytes from day 4 p.i., whereas the infection with Trichinella spiralis larvae induced an increase only from day 7 p.i. An antagonism was observed between the two parasite species: the primary infection with T. leonina led to a decrease in the total number of muscle larvae of T. spiralis, and, vice versa, the primary infection with T. spiralis suppressed the development of T. leonina. 相似文献
8.
Results of clinical and laboratory examination of animals experimentally infected with Taenia saginata eggs are described. At the early stage of infection, increased temperature, cough, muscle shaking and unstable pace were observed. The locomotive disorders disappeared only on day 50 p.i. Leukocytosis and peripheric eosinophilia were found at the early stage of infection. On days 14-28 p.i. the activity of serum creatine-kinase (CK) significantly increased. The activity of other enzymes (AST, ALT, LD, ALP and ALD) examined was increased only slightly and irregularly. The lipid content in blood serum markedly increased on days 9-16 p.i. 相似文献
9.
The development of the nematode Spinitectus inermis (Zeder, 1800), a parasite of the stomach of eels, Anguilla anguilla (L.) in Europe, was experimentally studied. Mayfly nymphs Caenis macrura, Ecdyonurus dispar, Heptagenia sulphurea, Potamanthus luteus and Seratella ignita from Portugal and the Czech Republic were found to serve as experimental intermediate hosts. After ingestion of the nematode eggs by the mayfly nymphs, the toothed first-stage larvae were released and penetrated into the body cavity of the intermediate host. There they moulted twice (on day 4 and 6 post infection [p.i.] at water temperatures of 20-25 degrees C), attaining the third infective stage. The definitive host, A. anguilla, undoubtedly acquires infection by feeding on mayfly nymphs harbouring infective-stage larvae. In an experimentally infected eel, the fourth-stage larva undergoing the third moult was observed 28 days p.i. at water temperature of 20 degrees C. The larval stages, including moulting forms, are described and illustrated. The prepatent period of S. inermis is estimated to be about two months. 相似文献
10.
L Kolárová 《Folia parasitologica》1986,33(1):15-19
Sporocysts from the goshawk (Accipiter gentilis) were experimentally transferred to the mouse (Mus musculus). It was found that the goshawk is the host of one of the sarcosporidians inducing muscle sarcocystosis in mice. Thin-walled, sporulated oocysts expelled by the goshawk measured 16.5-19.0 X 12.0-13.0 micron. Those which measured 12.0-13.5 X 8.2-9.0 micron were widely elliptical, with rounded poles. No asexual reproduction of parasites was detected in the viscera of mice. The cysts started to appear in skeletal muscles on day 20 after oral infection with 10,000 or 100,000 sporocysts per mouse. The cysts measuring 15-630 X 18-65 micron contained widely oval metrocytes (2.8-4.3 X 1.5-2.8 micron) or banana-shaped cystozoites (6.0-8.0 X 2.0-3.8 micron). Three months after infection the cysts were found also in the tongue of mice. No morphological differences were observed between the oocysts-sporocysts from owls (Tyto alba and Asio otus) and goshawk, not even between the muscle cysts of these sarcosporidians in mice. The possibility of passaging the species Sarcocystis dispersa from the long-eared owl through the digestive tract of goshawk is discussed. 相似文献
11.
M Gelnar 《Folia parasitologica》1991,38(2):123-131
It has been verified under laboratory conditions that constant and changing water temperature markedly affects the micropopulation growth in Gyrodactylus gobiensis parasite on the body surface of gudgeons (Gobio gobio L.). At a water temperature of 12 degrees C, the number of gyrodactylids gradually increased up to the mean value of 63 specimens per host, which was reached on days 27-28 after experimental infection. At a constant temperature of 18 degrees C, the parasites completely disappeared from the bodies of infected fishes on days 15-20 p.i. A similar effect was produced by gradually increasing temperature from 12 to 18 degrees C, while the decrease in water temperature from 18 to 12 degrees C resulted in an increase in the parasite number. 相似文献
12.
The importance of the IFA-test (Indirect Fluorescent Antibody Test) in the diagnosis of sarcocystosis in the intermediate host has been confirmed in the present paper. We assessed the time of the first appearance of serum antibodies in the intermediate host in mice inoculated experimentally with the species Sarcocystis dispersa. By means of the IFA-test, the first antibodies were found on day 20 p.i. Cross-reactions among antisera of S. dispersa and a heterologous antigen of S. cernae disclosed that the reaction was not species-specific, but genus-specific. In addition, we confirmed serologically that the antigenic structure of the genus Frenkelia was identical to that of the genus Sarcocystis, because the results of cross reactions obtained with the IFA-test were identical. 相似文献
13.
Using counterimmunoelectrophoresis and ELISA tests the dynamics of antibody production in serum of mice experimentally infected with Toxascaris leonina was studied. The production of antibodies using both tests has already been detectable in serum of mice from 7 days post infection (DPI) and their level persisted till the end of the experiment, i.e. till 77 DPI. The most positive were reactions of sera with Antigens 1 and 3. 相似文献
14.
The tissue reaction to Cysticercus bovis in the lung of cattle with an experimental infection was an inflammatory rim originating in the immediate vicinity of the cysts. The cysts recovered at days 83 and 102 p.i. contained living cysticerci. The rim was composed either of a layer of high histiocytes organized in palisades (at day 83 p.i.), or a lyer of flat histiocytes (at day 102 p.i.). The outer layer of the rim consisted of fibroblasts, reticular cells and a different number of eosinophil- and neutrophil luekocytes. On the periphery, the rim was formed by granulation tissue infiltrated with lymphoplasmocytes. At the border between the layers of the inflammatory rim there were conspicuous foci of a necrotic appearance typical of a tissue reaction to C. bovis. 相似文献
15.
In this study, a loop-mediated isothermal amplification (LAMP) assay was established to detect Toxoplasma gondii DNA in mice infected with T. gondii PRU strain. This LAMP assay was based on the sequence of highly repetitive B1 gene. The detection limit of T. gondii LAMP assay was 1 pg of T. gondii DNA, which was evaluated using 10-fold serially diluted DNA of cultured parasites. The LAMP assay was also highly specific for T. gondii and able to detect T. gondii DNA in urine of mice treated with dexamethasone at 90 day post infection (p.i.), although this assay could not detect the DNA in mice urine 2-6 days p.i. These results demonstrated that LAMP is effective for evaluation of therapy effectiveness for T. gondii infection. The established LAMP assay may represent a useful and practical tool for the routine diagnosis and therapeutic evaluation of human toxoplasmosis. 相似文献
16.
The terminal phase of the migration of Trichobilharzia regenti Horák, Kolárová et Dvorák, 1998 in the definitive host (Anas platyrhynchos f. domestica) was studied 12-27 days post infection (p.i.). Brain meninges were the last part of the nervous system where the worms were detected before their occurrence in the nasal cavity. In meninges, the parasites started to feed on red blood cells. Then the worms occurred in the nasal mucosa 14-25 days p.i. and the first immature eggs appeared 15 days p.i. The fully developed miracidia were recorded in the eggs from 17 days p.i. and freely in the nasal mucosa 19 days p.i. Infiltrates of lymphocytes, later also eosinophils and heterophils around the eggs and free miracidia, were observed from 15 and 19 days p.i., respectively. The haemorrhages occurring from 17 days p.i., and the granulomas with lymphocytes, eosinophils and heterophils forming around the eggs from 22 days p.i. were the most apparent pathological changes of nasal tissue. 相似文献
17.
Conidial germination, appressorial formation. penetration of epidermal walls, formation of intracellular vesicles and growth of intracellular hyphae in epidermal cells occurred within 12 h of inoculation. Hyphae then grew slowly between mesophyll cells for the next 12 h. Some papillae formed beneath appressoria and most infected epidermal cells retained stain by 24 h after inoculation, indicating major changes in cellular physiology. Slight differences between cultivars in some of these events were not related to resistance.
On the second day. intercellular hyphae emerged more extensively from the infection sites into the mesophyll of the susceptible cultivar Banks, and formed significantly larger mycelia than in the resistant cultivar BH1146 by 3-5 days from inoculation. Rapid intercellular growth then continued in the susceptible cultivar but not in the resistant cultivar. Necrotic lesions expanded faster in the susceptible cultivar from day 3. By day 10. most lesions in this cultivar were large and light brown with a conspicuous chlorotic margin but those in the resistant cultivar were small and dark brown with inconspicuous chlorosis. 相似文献
On the second day. intercellular hyphae emerged more extensively from the infection sites into the mesophyll of the susceptible cultivar Banks, and formed significantly larger mycelia than in the resistant cultivar BH1146 by 3-5 days from inoculation. Rapid intercellular growth then continued in the susceptible cultivar but not in the resistant cultivar. Necrotic lesions expanded faster in the susceptible cultivar from day 3. By day 10. most lesions in this cultivar were large and light brown with a conspicuous chlorotic margin but those in the resistant cultivar were small and dark brown with inconspicuous chlorosis. 相似文献
18.
S Lukes 《Folia parasitologica》1984,31(4):339-343
Immune response of rabbits experimentally infected with Ascaris suum was studied by indirect haemagglutination method. The animals were infected with the doses of 5,000, 10,000 and 20,000 infective eggs per animal. Positive reactions were observed from days 5-11 p.i., maximum reactions on days 11-19 p.i. A reinfection with the same doses (1x or 2x after 35 and 65 days) increased the antibody titre. The strongest individual reaction was recorded on day 19 p.i. in the group infected with the highest dose (titre 1 : 4096). The increased antibody titres persisted til the end of the experiment (82th day p.i.) in all groups. 相似文献
19.
通过对番茄感染南方根结线虫后其叶片中几种保护酶活性的变化进行研究。结果表明:接种南方根结线虫后,番茄叶片中的苯丙氨酸解氨酶(PAL)活性即开始低于对照,随后逐渐恢复至对照水平,15 d之后,酶活性又开始显著低于对照水平,一直持续到第30 d,酶活性恢复到对照水平;多酚氧化酶(PPO)活性变化受线虫侵染的影响较小,在试验期间与对照没有显著性差异;超氧化物歧化酶(SOD)的活性在接种后第1 d即显著低于对照水平,至第7 d的时候恢复至对照水平并持续至第30 d。过氧化物酶(POD)活性在1～20 d均显著高于对照水平。因此,POD活性可以作为早期判断番茄是否感染根结线虫的一项指标。 相似文献
20.
Brachiola algerae (Vavra et Undeen, 1970) Lowman, Takvorian et Cali, 2000, originally isolated from a mosquito, has been maintained in rabbit kidney cells at 29 degrees C in our laboratory. This culture system has made it possible to study detailed aspects of its development, including spore activation, polar tube extrusion, and the transfer of the infective sporoplasm. Employing techniques to ultrastructurally process and observe parasite activity in situ without disturbance of the cultures has provided details of the early developmental activities of B. algerae during timed intervals ranging from 5 min to 48 h. Activated and nonactivated spores could be differentiated by morphological changes including the position and arrangement of the polar filament and its internal structure. The majority of spores extruded polar tubes and associated sporoplasms within 5 min post inoculation (p.i.). The multilayered interlaced network (MIN) was present in extracellular sporoplasms and appeared morphologically similar to those observed in germination buffer. Sporoplasms, observed inside host cells were ovoid, contained diplokaryotic nuclei, vesicles reminiscent of the MIN remnants, and their plasmalemma was already electron-dense with the "blister-like" structures, typical of B. algerae. By 15 min p.i., the first indication of parasite cell commitment to division was the presence of chromatin condensation within the diplokaryotic nuclei, cytoplasmic vesicular remnants of the MIN were still present in some parasites, and early signs of appendage formation were present. At 30 min p.i., cell division was observed, appendages became more apparent, and some MIN remnants were still present. By two hours p.i., the appendages became more elaborate and branching, and often connected parasite cells to each other. In addition to multiplication of the organisms, changes in parasite morphology from small oval cells to larger elongated "more typical" parasite cells were observed from 5 h through 36 h p.i. Multiplication of proliferative organisms continued and sporogony was well underway by 48 h p.i., producing sporonts and sporoblasts, but not spores. The observation of early or new infections in cell cultures 12-48 h p.i., suggests that there may also exist a population of spores that do not immediately discharge, but remain viable for some period of time. In addition, phagocytized spores were observed with extruded polar tubes in both the host cytoplasm and the extracellular space, suggesting another means of sporoplasm survival. Finally, extracellular discharged sporoplasms tightly abutted to the host plasmalemma, appeared to be in the process of being incorporated into the host cytoplasm by phagocytosis and/or endocytosis. These observations support the possibility of additional methods of microsporidian entry into host cells and will be discussed. 相似文献