Neutrophils are important effector cells against protozoan extracellular parasite Entamoeba histolytica, which causes amoebic colitis and liver abscess in human beings. Apoptotic cell death of neutrophils is an important event in the resolution of inflammation and parasite's survival in vivo. This study was undertaken to investigate the ultrastructural aspects of apoptotic cells during neutrophil death triggered by Entamoeba histolytica. Isolated human neutrophils from the peripheral blood were incubated with or without live trophozoites of E. histolytica and examined by transmission electron microscopy (TEM). Neutrophils incubated with E. histolytica were observed to show apoptotic characteristics, such as compaction of the nuclear chromatin and swelling of the nuclear envelop. In contrast, neutrophils incubated in the absence of the amoeba had many protrusions of irregular cell surfaces and heterogenous nuclear chromatin. Therefore, it is suggested that Entamoeba-induced neutrophil apoptosis contribute to prevent unwanted tissue inflammation and damage in the amoeba-invaded lesions in vivo.
Animals ; Apoptosis/*physiology ; Entamoeba histolytica/*physiology ; Host-Parasite Relations/physiology ; Humans ; In Vitro ; Neutrophils/physiology/*ultrastructure ; Research Support, Non-U.S. Gov't

A survey was conducted to determine the extent of intestinal parasite infection in Bat Dambang, Cambodia in March 2004. A total of 623 fecal specimens was collected from kindergarten and schoolchildren and examined using the formalin-ether sedimentation technique. The overall infection rate of intestinal parasites was 25.7% (boys, 26.2%; girls, 25.1%), and the infection rates of intestinal helminthes by species were as follows: Echinostoma sp. 4.8%, hookworm 3.4%, Hymenolepis nana 1.3%, and Rhabditis sp. 1.3%. The infection rates of intestinal protozoa were; Entamoeba coli 4.8%, Giardia lamblia 2.9%, Iodamoeba butschlii 1.4%, Entamoeba polecki 1.1%, and Entamoeba histolytica 0.8%. There were no egg positive cases of Ascaris lumbricoides or Trichuris trichiura. All children infected were treated with albendazole, praziquantel, or metronidazole according to parasite species. The results showed that intestinal parasites are highly endemic in Bat Dambang, Cambodia.
Adolescent ; Age Factors ; Animals ; Cambodia/epidemiology ; Child ; Feces/parasitology ; Female ; Helminthiasis/*epidemiology ; Helminths/isolation & purification ; Humans ; Intestinal Diseases, Parasitic/*epidemiology ; Male ; Protozoa/isolation & purification ; Protozoan Infections/*epidemiology

We investigated the induction of resistance to Haemaphysalis longicornis infestation in rabbits that had been immunized with recombinant H. longicornis P27/30 protein. The success of immunological control methods is dependent upon the use of potential key antigens as tick vaccine candidates. Previously, we cloned a gene encoding 27 kDa and 30 kDa proteins (P27/30) of H. longicornis, and identified P27/30 as a troponin I-like protein. In this study, rabbits that were immunized with recombinant P27/30 expressed in Escherichia coli showed the statistically significant longer feeding duration for larval and adult ticks (P< 0.05), low engorgement rates in larval ticks (64.4%), and an apparent reduction in egg weights, which suggest that H. longicornis P27/30 protein is a potential candidate antigen for a tick vaccine. These results demonstrated that the recombinant P27/30 protein might be a useful vaccine candidate antigen for biological control of H. longicornis.
Animals ; Antibodies/blood ; Escherichia coli/genetics ; Female ; Gene Expression ; Insect Proteins/immunology ; Ixodidae/*immunology ; Microfilament Proteins/*immunology ; Rabbits ; Recombinant Proteins/*immunology ; Research Support, Non-U.S. Gov't ; Tick Infestations/*immunology/prevention & control

Toxoplasma gondii is an obligate intracellular protozoan parasite, which invades a wide range of hosts including humans. The exact mechanisms involved in its invasion are not fully understood. This study focused on the roles of Ca2+ in host cell invasion and in T. gondii replication. We examined the invasion and replication of T. gondii pretreated with several calcium modulators, the conoid extrusion of tachyzoites. Calmodulin localization in T. gondii were observed using the immunogold method, and Ca2+ levels in tachyzoites by confocal microscopy. In light microscopic observation, tachyzoites co-treated with A23187 and EGTA showed that host cell invasion and intracellular replication were decreased. The invasion of tachyzoites was slightly inhibited by the Ca2+ channel blockers, bepridil and verapamil, and by the calmodulin antagonist, calmidazolium. We observed that calcium saline containing A23187 induced the extrusion of tachyzoite conoid. By immunoelectron microscopy, gold particles bound to anti-calmodulin or anti-actin mAb, were found to be localized on the anterior portion of tachyzoites. Remarkably reduced intracellular Ca2+ was observed in tachyzoites treated with BAPTA/AM by confocal microscopy. These results suggest that host cell invasion and the intracellular replication of T. gondii tachyzoites are inhibited by the calcium ionophore, A23187, and by the extracellular calcium chelator, EGTA.
Animals ; Calcium/*physiology ; Calcium Channel Blockers/pharmacology ; Calmodulin/antagonists & inhibitors ; Chelating Agents/pharmacology ; Hela Cells ; Host-Parasite Relations ; Humans ; Ionophores/pharmacology ; Research Support, Non-U.S. Gov't ; Toxoplasma/drug effects/pathogenicity/*physiology

To evaluate the role of nitric oxide (NO) in IFN-gamma production and apoptosis of splenocytes in genetically different strains of mice with toxoplasmosis, BALB/c (a toxoplasmosis resistant strain) and C57BL/6 (a toxoplasmosis susceptible strain) mice were infected with Toxoplasma gondii cysts orally and subsequently injected intraperitoneally with aminoguanidine, an iNOS inhibitor (AG; 35 mg/kg per mouse daily for 14 days). When BALB/c or C57BL/6 mice were infected with T. gondii without AG treatment, number of brain cysts, NO and IFN-gamma production by splenocytes, and percentages of apoptotic splenocytes were increased compared to uninfected control mice without AG treatment. AG treatment increased the number of brain cysts, and reduced NO and IFN-gamma production in T. gondii-infected C57BL/6 mice. In contrast, in T. gondii-infected BABL/c mice, the number of brain cysts, and NO and IFN-gamma production of splenocytes was not altered by treatment with AG. However, the percentages of apoptotic splenocytes in T. gondii-infected BALB/c or C57BL/6 mice were not affected by AG treatment. These results suggest that NO modulates IFN-gamma production in T. gondii-infected C57BL/6 mice, and that NO is involved in mediating a protective response in toxoplasmosis susceptible, but not resistant, mice strain during acute infection.
Animals ; Apoptosis/drug effects/*immunology ; Comparative Study ; Female ; Guanidines/*pharmacology ; Interferon Type II/*biosynthesis ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Nitric Oxide/*biosynthesis ; Nitric-Oxide Synthase/*antagonists & inhibitors ; Research Support, Non-U.S. Gov't ; Species Specificity ; Spleen/immunology ; Toxoplasmosis, Animal/*immunology

The distribution, external morphology, radula, chromosome numbers of Planorbidae snails were studied. The specimens were collected at four stations in Nonsangun, Kongjugun, and Daedukgun which are located around Geum river. Three genera and three species of Planorbidae, Hippeutis cantori, Segmentina hemisphaerula and Gyraulus convexiusculus, were collected. H. cantori was the most abundant species among the three species. G. convexiusculus was the least abundant one. Each species could be identified on the basis of its external characteristic, since the periphery of each species has a peculiar shape. H. cantori was the largest one among the three species. The radula formula of each species was very similar to other species. The size of radula was proportional to the size of shell. The radula formulae of H. cantori, S. hemisphaerula, and G. convexiusculus were 29:1:29, 23:l:23, and 16:1:16 respectively. The difference of radula formula could be found in the total numbers of laternal and marginal teeth. The haploid chromosome number of H. cantori was eighteen (n=18). S. hemisphaerula and G. convexiusculus were assumed to be same in their chromosome numbers (n=18).
malacology ; Planorbidae ; morphology ; chromosome ; epidemiology ; Hippeutis cantori ; Segmentina hemisphaerula ; Gyraulus convexiusculus

Aedes alboscutellatus was recorded first in Korea. This mosquito was collected near Demilitarized Zone of Korea Penninsula from 1979-1980. Its morphology and taxonomical position was described(abstracted from English content).
parasitology-arthropoda ; mosquito ; Aedes alboscutellatus ; morphology ; taxonomy

A survey on vegetables, which consisted of lettuce (Lactuca sativa), young radish (Raphanus sapivus), and chinese cabbage (Brassica pekinensis) collected from 6 markets in the Taegu city, was conducted for the discovery of helminth eggs and larvae, from July 1982 to June 1983. The results were compared with the data obtained from vegetables collected at the same markets by Lee (1969) and Choi and Lee (1972). Both sides of vegetable leaves were washed carefully with a hard brush, and the species of parasites and the mean number of parasites per 200 g of vegetable were determined. When vegetable were examined, 4 species of parasite eggs (ascarid, Trichostrongylus, liver fluke, and hookworms) and 2 larvae (filariform and rhabditoid larvae) were found. Of the parasite discovered, ascarid egg was found to be highest (4.2 percent), followed by hookworm egg (3.6 percent). The mean number of ascarid egg per 200 grams of vegetable was 0.6 in young radishes, and 0.3 in both lettuces and chinese cabbages. Similarly, the number of filariform larva of hookworm was 0.4 in young radishes, 0.3 in lettuces, and 0.l in chinese cabbages, and the number of rhabditoid larva was 0.2 in young radishes, 0.1 in lettuces, and 0.05 in chinese cabbages. In the results obtained by Lee (1969) and Choi and Lee (1972), the mean number of ascarid egg per 200 grams of vegetable was 7.5 in young radishes, 3.l in lettuces, and 0.5 in chinese cabbages. By contrast, in the present study it was 0.6 in young radishes and 0.3 in both lettuces and chinese cabbages. These results suggest that there has been significant reduction in the incidence of parasite egg and larva on vegetable leaves during the past 10 years.
parasitology-helminth-nematoda-trematoda ; ascarid ; Trichostrongylus ; Clonorchis sinensis ; hookworm ; filariform larva ; rhabditoid larva ; egg ; epidemiology

A total of 2,026 leprosy patients of the National Sorokdo Hospital was examined their intestinal parasites by cellophane thick smear method in January 1983. The egg positive cases of Taenia spp. were treated with bithionol and the segments of Taenia were collected for species identification. The results were as follows: Total egg positive rate of any kind helminth was 78.2 percent and cumulative total was 85.2 percent. The egg positive rate for each helminth was as follow; Taenia spp. 3.4 percent, Ascaris lumbricoides 4.5 percent, Trichuris trichiura 72.l percent, Clonorchis sinensis 2.8 percent and other 0.05 percent. A total of 66 Taenia egg positive cases was treated; out of them proglottids of Taenia were collected from 26 cases. All of the collected worms were identified as T. saginata. The results revealed significantly high egg positive rate of T. trichiura. However, A. lumbricoides was found to be controlled considerably by repeated chemotherapy during past 3 years. If chemotherapeutic agent is replaced with oxantel-pyrantel tablet, better result is expected. No clue was found for prevalence of T. solium from both human and the pig in the island.
parasitology-helmith-nematoda-trematoda-cestoda ; trichuriasis ; Trichuris trichiura ; Taenia spp. ; Ascaris lumbricoides ; Clonorchis sinensis ; taeniasis ; ascariasis ; clonorchiasis ; Taenia saginata ; epidemiology

Mebendazole was tested for its efficacy in individual treatment and mass control of Trichuris trichiura infection in Korea. The results were as follows: The efficacy of mebendazole in 430 cases 3 weeks after treatment with mebendazole(100-1,200 mg) was not so satisfactory (15.0-64.0 and 24.6-95.2% in cure and egg reduction rates respectively). But it was observed that the higher the total dose of the drug the better the efficacy. The egg positive rate of the inhabitants in mass control programme by 600 mg mebendazole decreased form 40.0 to 5.6 % during one year, May 1982-May 1983, by repeated blanket mass chemotherapy every 3 months (in conventional regimen), while the decrease was less marked or unrecognizable in 3-month (signle or two divided doses), 6-month, 12-month interval and placebo control groups. From the results, it was concluded that, although mebendazole was not highly effective in individual treatment of T. trichiura infection, it was fairly useful in mass cotrol, by repeated mass chemotherapy every 3 months.
parasitology-helmith-nematoda ; trichuriasis ; Trichuris trichiura ; chemotherapy-mebendazole ; mebendazol