A pathogenic free-living amoeba, Naegleria fowleri, is a causative protozoan parasite of primary amebic meningoencephalitis in human and experimental animals. It is known that humoral and cellular immunity contribute as the defence mechanism of host against this organism. Recently splenectomy has been argued on its effect on host defence mechanisms. The present study was aimed to observe the effect of immunization in splenectomized mice. For immunization, 5-10 x 10(5) trophozoites of Naegleria fowleri o 359 were intraperitoneally inoculated once a week for two weeks to BALB/c mice, and 5-10 x 10(4) of ameba trophozoites were intranasally inoculated for infection after splenectomy and/or immunization. ELISA technique was applied for the detection of serum IgG antibody levels. Experimental animals were divided into 4 groups; I. splenectomized and immunized; II. splenectomized only; III. immunized only; IV. not splenectomized nor immunized. The results obtained were as follows: Mortality rates of splenectomized and immunized mice in group I (38.1 percent) and immurized only in group III (25.0 percent) were lower than those of not immunized mice in group II(50 percent) and control group, IV (46.4 percent). Survival times of mice in group I, II, III and IV were 20.1+/-3.6, l7.3+/-4.5, 20.4+/-7.0 and 19. 6+/-7.6 days respectively, and there were no significant differences between them. ELISA values (absorbance at 492 nm) of group I (1.10+/-0.29) and group III (1.31+/-0.28) were signficantly higher than that of group IV(0.24+/-0.37) at day 31 of infection (p<0.05). Conclusively, it is presumed that humoral immunity against N. flowleri may operate as ever, after immunization, even though the mouse was splenectomized.
parasitology-protozoa ; Naegleria fowleri ; mouse ; spleen ; immunology

A case of Paragonimus westermani cysts found deep inside the spleen is described. This spleen was from a dog that was experimentally infected via oral route with a hundred metacercariae and was killed 3 months after. At autopsy, beside the usual lesions due to Paragonimus in the lungs, the spleen was the site of multiple parasitic cysts. The involved spleen was slightly enlarged and showed an area of hemorrhagic dome on the capsular surface. There found a total of 8 adult worms in four well demarcated parasitic cysts containing a pair of worms each. All of them were found deep into the splenic parenchyme and were surrounded by a well formed connective tissue wall, thus resembling the features of the pulmonary paragonimiasis. The route of infection was assumed to be a direct transcapsular invasion during the phase of larval migration.
parasitology-helminth-trematoda ; paragonimiasis ; Paragonimus westermani ; dog ; case report ; spleen

To elucidate the effect of splenectomy on the development of experimental primary amoebic meningoencephalitis in mice, the death rate and survival time of mice infected intranasally with Naegleria fowleri trophozoites 5 x 10(4) cultivated in CGVS medium were compared according to the age when splenectomy was done, and post-operation until experimental infection. Immunodiffusion was undergone to detect the presence of serum antibody due to N. fowleri infection in mice. Polyacrylamide gel electrophoresis was done to compare the protein fractions of mouse serum in each experimental groups. In experiment I, splenectomy was done 3 weeks and infection 4 weeks after birth, the death rate of control, sham operated and splenectomized group were 100 percent, 85 percent and 95 percent, and the mean survival time after infection 7.3 days, 7.5 days and 7.8 days, respectively. In experiment II, splenectomy was undergone 3 weeks and infection 6 weeks after birth, the death rate of control, sham operated and splenectomized group were 95 percent, 95 percent and 95 percent , and the mean survival time after infection 12.1 days, 11.5 days and 11.5 days, respectively. In experiment III, splenectomy was done 5 weeks and infection 6 weeks after birth, the death rate of control, sham operated and splenectomized group were 95 percent, 90 percent and 95 percent, and the mean survival time after infection 8.1 days, 8.3 days and 8.5 days, respectively. By Ouchterlony immunodiffusion, anti-N. fowleri antibody in the serum of mouse with primary amoebic meningoencephalitis was detected against a N. fowleri antigen, which was prepared by ultrasonication of N. fowleri trophozoites, each reacting two lines of precipitation. The patterns of serum fractions by polyacrylamide gel electrophoresis were different between control and sham operated groups from splenectomized group in fraction II, III and V, the sera of which were collected after N. fowleri infection. This results may be summarized as that splenectomy has no effect on the development of primary amoebic meningoencephalitis in mice.
parasitology-protozoa ; Naegleria fowleri ; meningoencephalitis ; brain ; immunology ; spleen ; brain

Eimeria tenella, an intracellular protozoan parasite infecting the epithelial cells of the ceca of chickens, causes severe diarrhea and bleeding that can lead its host to death. It is of interest that E. tenella first penetrate into the mucosal intraepithelial lymphocytes (IEL) before they parasitize crypt or villous epithelial cells. This in vitro study was undertaken to know whether the penetration of E. tenella into such a lymphoid cell is a beneficial step for the parasite survival and development. Three sequential experiments were performed. First, the in vitro established bovine kidney cell line, MDBK cells, were evaluated for use as host cells for E. tenella, through morphological observation. Second, the degree of parasite development and multiplication in MDBK cells was quantitatively assayed using radioisotope-labelled uracil (3H-uracil). Third, the E. tenella sporozoites viability was assayed after preincubation of them with chicken spleen cells. E. tenella oocysts obtained from the ceca of the infected chickens were used for the source of the sporozoites. Spleen cells (E) obtained from normal chickens (FP strain) were preincubated with the sporozoites (T) at the E:T ratio of 100:1, 50:1 or 25:1 for 4 or 12 hours, and then the mixture was inoculated into the MDBK cell monolayer. Morphologically the infected MDBK cells revealed active schizogonic cycle of E. tenella in 3-4 days, which was characterized by the appearance of trophozoites, and immature and mature schizonts containing merozoites. The 3H-uracil uptake by E. tenella increased gradually in the MDBK cells, which made a plateau after 48-60 hours, and decreased thereafter. The uptake amount of 3H-uracil depended not only upon the inoculum size of the sporozoites but also on the degree of time delay (preincubation; sporozoites only) from excystation to inoculation into MDBK cells. The 3H-uracil uptake became lower as the preincubation time was prolonged. In comparison, after preincubation of sporozoites with spleen cells for 4 or 12 hours, the 3H-uracil uptake was significantly increased compared with that of control group. From the results, it was inferred that, although the penetration of E. tenella sporozoites into the lymphoid cells such as IEL is not an essential step, it should be at least a beneficial one for the survival and development of sporozoites in the chicken intestine.
Cattle- ; Cell-Line ; Cells,-Cultured ; Chickens- ; English-Abstract ; *Eimeria-growth-and-development ; *Kidney-parasitology ; *Lymphocytes-parasitology ; *Spleen-cytology

The present experimental study was undertaken to observe the chronological change of the worm structure of Clonorchis sinensis and the pathological findings of the liver when this fluke was inoculated to the mouse intraperitoneally. The recovery rate, survival rate, location and size of the inoculated worms as well as the pathological changes of the liver were investigated for the comparison among the groups of mice, classified by number of worms and the duration of experiment. The results obtained were summarized as follows: The recovery and survival rates of the worms decreased especially 28 days after the inoculation. Most of worms (90.l percent) were collected from the peritoneal cavity and some of worms were found tightly adherent to the capsules of the liver, spleen, stomach, intestine and diaphragm. There were no worms recovered penetrated in the parenchymes of these organs. The mean worm size after inoculation was smaller than that before inoculation. At the 10th day after the inoculation, the shrinkage of posterior portion of the worm body was observed. Remarkable atrophy in the reproductive organs of the worm, such as spermatheca, testes, vitelline glands and ovary was frequently observed at the 10th day of inoculation. Histopathologically the liver failed to show any parasitic worm inside the intrahepatic biliary system. However, multiple well formed egg-containing granulomas were present along the liver capsule. These necrotic granulomas were occasionally found under the fibrotic liver capsule. Focal necrosis and focal phlebitis together with vascular dilatation were prominent features seen in the liver. The bile duct in the liver showed mild dilation of the lumen, flattening of epithelial cells and periductal small round cell infiltration. Neither adenomatous hyperplasia nor portal fibrosis was seen in the whole experimental groups. Foci of intralobular micro-granulomas were found in some experimental animals. The worms recovered in the capsule of the liver were degenerated and necrotized. Usually, there were remarkable capsulitis and granuloma formation around the eggs.
parasitology-helminth-trematoda ; Clonorchis sinensis ; pathology ; liver ; spleen ; stomach ; intestine ; diaphragm ; granuoma ; peritoneal cavity

This study was to observe the changes of blastogenic responses of splenic lymphocytes to T-cell mitogens, N. fowleri lysate and concanavalin A, and serum antibody titer during the course of experimental PAM in mice. Naegleria fowleri, strain 0359, was cultured in the CGVS medium axenically and inoculated intranasally with 7 x 10(4) trophozoites for the development of experimental PAM in mice. The amoebae were subjected to ultrasonication and centrifuged at 20,000 g for 60 minutes, and filtered through 0.2 micro-m filter membrane. The supernatant, N. fowleri lysate, was used as T-cell mitogen, and antigen for ELISA. The serum antibody was examined by ELISA using peroxidase conjugate. Two hundred micro-l of 10(6) splenocytes in RPMI 1640 containing 10% fetal calf serum were added to each well of a microtiter plate. To each well was added T-cell mitogens, 100 micro-g/ml of N. fowleri lysate or 4 micro-g/ml of con. A, and the plates were incubated for 42 hours at 37 C in 5% CO(2) incubator. Cultures were pulsed with 1 micro-Ci of methyl-(3H)-thymidine 6 hour before harvesting. The mean blastogenic response of the splenocytes to N. fowleri lysate was reduced, whereas that to con. A was also reduced up to on day 11 after infection. Both of these results were statistically significant compared with those of uninfected control group. The serum antibody titers were increased gradually up to day 15. The results indicated that there was an impairment of the blastogenic response of splenocytes to N. fowleri lysate during the acute course of experimental PAM in mice.
parasitology-protozoa ; Naegleria fowleri ; primary amoebic meningoencephalitis ; immunology ; spleen ; lymphocyte ; mouse

To determine alteration of immune responses during visceral larva migrans (VLM) caused by Toxascaris leonina at several time points, we experimentally infected mice with embryonated eggs of T. leonina and measured T-helper (Th) cell-related serial cytokine production after infection. At day 5 post infection (PI), most larvae were detected from the lungs, spleen, intestine, and muscle. Expression of thymic stromal lymphopoietin (TSLP) and CCL11 (eotaxin) showed a significant increase in most infected organs, except the intestine. However, expression of the CXCL1 (Gro-alpha) gene was most highly enhanced in the intestine at day 14 PI. Th1-related cytokine secretion of splenocytes showed increases at day 28 PI, and the level showed a decrease at day 42 PI. Th2-related cytokine secretion of splenocytes also showed an increase after infection; in particular, IL-5 level showed a significant increase at day 14 PI, and the level showed a decrease at day 28 PI. However, levels of Th17-related cytokines, IL-6 and IL-17A, showed gradual increases until day 42 PI. In conclusion, Th1, Th2, and Th17-related cytokine production might be important in immune responses against T. leonina VLM in experimental mice.
Animals ; Brain/parasitology ; Cytokines/*metabolism ; Female ; Gene Expression Regulation ; Heart/parasitology ; Interleukins/*metabolism ; Intestines/parasitology ; Larva Migrans, Visceral/*immunology/parasitology ; Liver/parasitology ; Lung/parasitology/pathology ; Mice ; Mice, Inbred C57BL ; Muscles/parasitology ; Spleen/parasitology ; Th1 Cells/immunology ; Th17 Cells/immunology ; Th2 Cells/immunology ; Toxascaris/*immunology

Leishmania (L.) tropica is a causative agent of cutaneous leishmaniasis, and occasionally of visceral or viscerotropic leishmaniasis in humans. Murine models of Leishmania infection have been proven to be useful for elucidation of mechanisms for pathogenesis and immunity in leishmaniasis. The aim of this study was to establish a murine model for human viscerotropic leishmaniasis, and the growth pattern of L. tropica was studied in different tissues of BALB/c mice in order to find out whether the parasite visceralizes in this murine model. L. major was used as a control as this species is known to cause a progressive infection in BALB/c mice. L. tropica or L. major was injected into the footpad of mice, and thickness of footpad, parasite loads in different tissues, and the weight of the spleen and lymph node were determined at different intervals. Results showed that L. tropica visceralizes to the spleen and grows there while its growth is controlled in footpad tissues. Dissemination of L. tropica to visceral organs in BALB/c mice was similar to the growth patterns of this parasite in human viscerotropic leishmaniasis. The BALB/c model of L. tropica infection may be considered as a good experimental model for human diseases.
Animals ; *Disease Models, Animal ; Female ; Foot/parasitology ; Humans ; Leishmania major/growth & development ; Leishmania tropica/*growth & development ; Leishmaniasis/*parasitology ; Lymph Nodes/parasitology/pathology ; Mice ; Mice, Inbred BALB C ; Organ Size ; Spleen/parasitology/pathology

Hydatid disease (HD) is an endemic illness in many countries, and it poses an important public health problem that's influenced by peoples' socioeconomic status and migration that spreads this disease. Although rare, it may occur in any organ or tissue. The most common site is the liver (59-75%), followed in frequency by lung (27%), kidney (3%), bone (1-4%) and brain (1-2%). Other sites such as the heart, spleen, pancreas and muscles are very rarely affected. Unusual sites for this disease can cause diagnostic problems. This pictorial essay illustrates various radiological findings of HD in the liver, spleen, kidney, pancreas, peritoneal cavity, omentum, adrenal, ovary, lung, mediastinum and retroperitoneum. Familiarity with the imaging findings of HD may be helpful in making an accurate diagnosis and preventing potential complications.
Abdominal Cavity/parasitology/radiography ; Adolescent ; Adult ; Child ; Child, Preschool ; Contrast Media/administration & dosage ; Digestive System/pathology/radiography/ultrasonography ; Digestive System Diseases/diagnosis/parasitology ; Echinococcosis/*diagnosis/parasitology/*radiography ; Endocrine Glands/parasitology/radiography ; Female ; Humans ; Kidney/parasitology/pathology ; Liver/parasitology/radiography ; Lung/parasitology/radiography ; Magnetic Resonance Imaging/methods ; Male ; Mediastinum/parasitology/radiography ; Middle Aged ; Pancreas/parasitology/radiography ; Radiographic Image Enhancement/methods ; Spleen/parasitology/radiography ; Tomography, X-Ray Computed/methods

In order to understand the tissue responses of albino rat host against Paragonimus iloktsuenensis infection, the histopathological changes of the spleen and the lungs in 6 experimental groups of rats were observed in relation with the growth, maturation and migration of this lung fluke. Rats of the experimental groups, each group consisted of 5 rats, were infected with the metacercariae of P. iloktsuenensis which were isolated from brackish water crab, Sesarma dehaani, and were kept for 3 days, 3 weeks, 4 weeks, 7 weeks, 10 weeks and 14 weeks of infection period. Peripheral blood smear slides for the differential leukocyte count were prepared and also worm collection was completed immediately after the infection period. Paraffin sections of the spleen and the lung tissue were stained with hematoxylin-eosin and methyl-green-pyronin (MGP) stain. Those materials from the experimental groups were examined in comparison with the materials obtained from control group, with special reference to immunologic aspects of host response. The results obtained were as follows: The counts of large pyroninophilic cell (LPC) in the periarterial sheath of spleen were rapidly increased in earlier period of infection, and those of peribronchial lymphatic tissue started to increase after the penetration of lungfluke into the lungs. The LPC counts of both the spleen and the lungs were on the decrease in conjunction with the necrosis of the lung fluke in 14th week of infection. On observing differential leukocyte count of peripheral blood smear, the fluctuation of lymphocyte count was proportional to that of LPC count, and the lymphocyte count was consistently higher than that of normal rats. On the other hand, neutrophil count of experimental group showed reciprocal relation to the LPC counts. The nature and characteristics of pulmonary lesion produced by the P. iloktsuenensis were just the same as those produced by P. westermani. The lesions were represented by thick and fibrosclerotic cavern, granuloma due to eggs, pneumonic process and cellular infiltrations.
parasitology-helminth-trematoda ; paragonimiasis ; Paragonimus iloktsuenensis ; histology ; pathology ; lung ; spleen ; granuloma ; pneumonia ; hematoxylin-eosin ; methyl-green-pyronin