It is well established that guinea pig, rabbit and rat are equally susceptible to experimental infection with the Chinese liver fluke, Clonorchis sinensis. However, little work has been done on the studies of the host-parasite relationships between the liver fluke and mouse host. The experiments were undertaken to investigate the susceptibility, development and sexual maturity of Clonorchis sinensis in mouse host. The metacercariae of C. sinensis used in these experiments were isolated from the fish, Pseudorasbora parva by digestion technic. And in all these studies the mice weighing around 20 g were commercially purchased and infected with the metacercariae under slightly narcotized condition with ether. The animals were starved overnight before infection. The mature metacercariae, e.g. 5, 10, 20, 30, 50, 200 were given orally into stomach by means of the polyethylene tubing (intramedic, Clay Adams, Inc.PE-90/S12) respectively to each mouse of groups ranging 4 to l5. After various period of infection, the mouse liver was first opened along the common bile duct and cut into small pieces for collecting and counting the worms. For the histopathological examination of the liver, the tissue specimens were fixed in formalin, sectioned and stained with haematoxylin-eosin. Another experiment was separately set up for the study of egg laying capacity of C. sinensis in mice. The following results were obtained: Mice were successfully infected with metacercariae of C. sinensis in all cases of the groups except the group given 5 and 10 metacercariae, in which the infection was not established in one case of each group. Therefore it is assumed that mice are susceptible to infection with this worm. In an earlier period ot infection, the worms were found mostly in common bile duct and intrahepatic biliary passages with same rate, however in later period, they were seen rather in the intrahepatic biliary passages (73 percent) than in common bile duct and gall bladder. The recovery rate of fully matured adult worms (less than 10 percent) was lower than that of the average recovery rate of the worms in general (22.3 percent). Under same age of infection or even in same host, the size of collected worms showed the great variations. Oral sucker was smaller in size than ventral sucker in the early stage of infection. After 11 days of infection it reversed. The posterior part of body length began to elongate since 5 days after infection, and therefore the ratio of antero-posterior part became l to 3. Fully matured adult worms were only collected after 30 days of infection. The first positive appearance of eggs in feces was on the 17th and 18th day after infection. However, the egg-laying capacity in mouse host seemed to be stabilized since 30 days after infection. Histopathologically, the cystic dilatation of medium to small biliary passages was noted and focal but diffusely scattered necrosis of the liver cells with scarce inflammatory cells was also observed as well as the hepatocellular degeneration, diffuse vascular congestions and adenomatous proliferationof bile duct.
parasitology-helminth-trematoda-Clonorchis sinensis ; mouse ; host-parasite relationship ; worm recovery ; histology ; pathology ; liver

The effects of various digestive enzymes, fresh biles, and bile acids on the hatching and activation of the eggs of Taenia saginata, T. pisiformis, T. solium, Hymenolepis nana, and Moniezia expansa have been investigated. On the basis of the results of the present study author attempted to elucidate the specificity of host-parasite relationships in the tapeworm infections. The results were summarized as follows: In case of the ova of T. saginata, pretreatment with artificial gastric juice before contact of intestinal juice is required to bring the disintegration of the embryophore and activation of the embryo. However the ova of T. solium and T. pisiformis may be disintegrated and activated directly into the artificial intestinal juice without the above pretreatment. Among the digestive enzymes applied in this experiment, trypsin was found most effective on the hatching. No hatching of the ova of H. nana and M. expansa was observed in the above artificial hatching-activating solutions. The fresh biles and bile salts were more effective on the hatching and activation of Taeniid ova than sodium taurocholate and sodium deoxycholate. It is turned out that the digestive enzymes or bile acids in the intermediate hosts may, not apparently be essential factor of determining the specificity of host-parasite relationships.
parasitology-helminth-cestoda ; Taenia saginata ; Taenia pisiformis ; Taenia solium ; Hymenolepis nana ; Moniezia expansa ; egg hatching ; host-parasite relationship ; trypsin ; artificial intestinal juice

Eosinophilic leukocytes function in host protection against parasitic worms. In turn, helminthic parasites harbor specific molecules to evade or paralyze eosinophil-associated host immune responses; these molecules facilitate the migration and survival of parasitic helminths in vivo. This competition between eosinophil and worm leads to stable equilibria between them. An understanding of such dynamic host-eosinophil interactions will help us to uncover mechanisms of cross talk between host and parasite in helminth infection. In this review, we examine recent findings regarding the innate immune responses of eosinophils to helminthic parasites, and discuss the implications of these findings in terms of eosinophil-mediated tissue inflammation in helminth infection.
Animals ; Eosinophils/*immunology/parasitology ; Helminthiasis/*immunology/*parasitology ; Helminths/*immunology ; Host-Parasite Interactions ; Humans

OBJECTIVETo detect the species of larval trematodes (cercariae) in Melanopsis praemorsa snails from 5 different fresh water bodies in Palestine.

METHODSA total of 1 880 Melanopsis praemorsa snails were collected from different fresh water bodies in Palestine from October, 2008 to November, 2010. Cercariae in Melanopsis praemorsa snails were obtained by lighting and crushing methods. The behavior of cercariae was observed using a dissecting microscope.

RESULTSThree different species of larval trematodes were identified from Melanopsis praemorsa snails collected only from Al-Bathan fresh water body, while snails from other water bodies were not infected. These species were microcercous cercaria, xiphidiocercaria and brevifurcate lophocercous cercaria. These cercariae called Cercaria melanopsi palestinia I, Cercaria melanopsi palestinia II and Cercaria melanopsi palestinia III have not been described before from this snail in Palestine. The infection rate of Melanopsis praemorsa collected from Al-Bathan fresh water body was 5.7%, while the overall infection rate of snails collected from all fresh water bodies was 4.3%. Details are presented on the morphology and behavior of the cercariae as well as their development within the snail.

CONCLUSIONSThese results have been recorded for the first time and these cercariae may be of medical and veterinary importance.

One of a rapid growing mycobacteria (RGM), Mycobacterium abscessus (MAB), is the most causative agents of RGM pulmonary disease. MAB can change their morphology that smooth (S) type to more virulent type of rough (R). Bacterial invasion into host cells is an important first step to initiate their infection. The phagocytic and invasion mechanisms of Mycobacterium tuberculosis through the host-parasite interaction have been researched. Although MAB causes a wide range of clinical diseases, little is known about their invasion ability or why the R type is more virulent than the S type. To compare invasion ability of R with S types, their infection abilities to dermal fibroblast, HaCaT cells, A549 cells and bone marrow derived macrophages were analyzed. After 2 h of infection, intracellular survival numbers of the R type were significantly higher in all infected cells than S types. The fluorescence-activated cell sorting (FACS) and confocal microscopy assay also revealed that red fluorescent amount and intracellular bacterial numbers in all of the cells infected with MAB R type expressing the red fluorescent protein (RFP) were significantly higher than the S type. Our data suggest that the virulence of MAB is proportionally related to the invasion ability into mammalian cells and macrophages.
Fibroblasts ; Flow Cytometry ; Host-Parasite Interactions ; Infection ; Lung Diseases ; Macrophages ; Microscopy, Confocal ; Mycobacterium tuberculosis ; Mycobacterium* ; Virulence

Since almost all patients suffering from acute hematogenous osteomelitis, due to Staph. aureus, are under 20 year old, it may be assumed that the host-parasite relationships, between the young and actively growing bodies and the organisms, might be somewhat different from the ones prevailed in the adult bodies. And it is also known that the administration of various hormones may produce significant influences upon the susceptibity and resistance of host. It was thought worthwile to study the host reactions to the introduction of organisms and the effects of cortisone or prehormone administration to the infected animals. Thus, ca. 5×10⁷ viable cells of Staph. aureus were inoculated i.v. into young rabbits, weighing 1–1.5 kg., of around 2 months old. The number of viable units of Staph. aureus were followed in the circulating blood and urine of the inoculated animals with or without treatment of cortisone or prehormone. The results of observations might be summerized as follows: 1. The organisms were removed rapidly from the circulating blood of infected rabbits without treatment. The number of viable units increased more or Iess slowly, peak being three to eight days after inoculation, in the urine of infected rabbits without treatment. 3. In the of infected rabbits with daily administration of cortisone, small number of organisms could be cultured throughout the 17 days of observation. 4. The number of viable units in the urine of infected rabbits with daily adminstration of cortisone sho wed significant increase upon the onset of cortisone administration and then decreased slowly. 5. Prehormone administration appeared to produced no significant influence on the number or viable stapylococci in the blood and urine of infected rabbits.
Adult ; Animals ; Cortisone ; Host-Parasite Interactions ; Humans ; Rabbits ; Staphylococcus aureus ; Staphylococcus

Helminth infections are widespread worldwide, and pose a serious threat to human health and animal husbandry development. Understanding of helminth-host interactions is critical to effective control and ultimate eradication of helminthiasis. Following host infections, helminth infections firstly initiate innate immune responses and then mediate adaptive immune responses. Type 1 immune responses are predominant at early stage of helminth infections, which mainly play anti-infective actions, and type 2 immune responses are predominant at late stage of infections, which are associated with helminth immune evasion and aggravation of tissue damages. This review summarizes the progress of researches on type 1/2 immune responses-associated signaling pathways mediated by helminth infections in hosts.
Animals ; Humans ; Helminthiasis ; Helminths ; Immunity, Innate ; Signal Transduction ; Host-Parasite Interactions

Staphylococcus aureus infections are often life-threatening. Relatively little is known about the host response to these infections, in particular, the implication of apoptosis induced by this microorganism. In this study, we have shown that S. aureus was cytotoxic to J774A.1 cell, a murine macrophage cell line. The cell death mediated by S. aureus occurred through apoptosis, as shown by increase in the proportion of fragmented host cell DNA. Although phagocytosis and NO production had important role in the induction of apoptosis, the contact between bacteria and host cells was not essential for this pathway. A certain bacterial product could also induce typical caspase-dependent apoptosis of J774A.1 cell. It is expected that new interpretation may be possible to host-parasite relationship based on these results.
Animals ; Apoptosis* ; Bacteria ; Cell Death ; Cell Line* ; DNA ; Host-Parasite Interactions ; Macrophages* ; Mice* ; Phagocytosis ; Staphylococcus aureus* ; Staphylococcus*

The present study was performed to observe histopathological changes in tissues of Bithynia siamensis goniomphalos (Gastropoda, Bithyniidae) incubated in crude extract solutions of camellia (Camellia oleifera) seed and mangosteen (Garcinia mangostana) pericarp, and furthermore to estimate the molluscicidal effects of 2 plant substances. Substantial numbers of bithyniid snails were incubated in various concentrations of 2 plant solution for 24 hr. As the positive control, snails incubated in various concentrations of niclosamide, a chemical molluscicide, were used. The histopathological findings were observed in sectioned snail specimens of each experimental and control groups. The results showed that both camellia and mangosteen extracts had molluscicidal effects at 24 hr with 50% lethal concentration (LC50) at concentrations of 0.003 and 0.002 g/ml, respectively, while niclosamide had LC50 at concentrations 0.599 ppm. B. siamensis goniomphalos snail tissues (foot, gill, and digestive system) showed disruption of columnar muscle fibers of the foot, reduction of the length and number of gill cilia, numerous mucous vacuoles, and irregularly shaped of epithelial cells. Irregular apical and calciferous cells, dilatation of the digestive gland tubule, and large hemolymphatic spaces, and irregular apical surfaces, detachment of cilia, and enlargement of lysosomal vacuoles of epidermis were also shown in all groups. By the present study, it is confirmed that 2 plants, camellia and mangosteen, are keeping some substance having molluscicidal effects, and histopathological findings obtained in this study will provide some clues in further studies on their action mechanisms to use them as natural molluscicides.
Animals ; Camellia/*chemistry ; Disease Vectors ; Garcinia mangostana/*chemistry ; Gastropoda/*drug effects ; Host-Parasite Interactions ; Plant Extracts/chemistry/*pharmacology ; Seeds/chemistry

Metacercariae of Acanthoparyphium marilae Yamaguti, 1934 (Digenea: Echinostomatidae) were discovered in an intertidal clam, Mactra veneriformis, in a southwestern coastal area of the Republic of Korea. A total of 128 metacercariae were detected from 10 clams examined. They were round, 320 m in average diameter, with 23 collar spines. They were fed experimentally to chicks, and 10 days later adult flukes were obtained. The adults were morphologically characterized by the head collar with a single row of 23 dorsally uninterrupted spines, without special end group spines, a round ventral sucker, 2 round and tandem testes, and vitellaria extending at lateral fields from the posterior extremity not beyond the middle level of the posterior testis. The most characteristic feature of this species was the limited distribution of vitellaria, which differs from Acanthoparyphium tyosenense Yamaguti, 1939, the metacercariae of which are encysted in the same mollusk species. This is the first report in which the metacercariae of this species were detected, and the intertidal bivalve, M. veneriformis, has been identified as a second intermediate host for A. marilae.
Animals ; Bivalvia/*parasitology ; Chickens ; Echinostomatidae/anatomy & histology/cytology/*isolation & purification ; *Host-Parasite Interactions ; Korea ; Trematode Infections/parasitology/veterinary