Intestinal Parasite Infections among Inhabitants in Yanbian Prefecture, Jilin Province, China

To investigate the prevalence of intestinal parasite infections in Yanbian Prefecture, Jilin Province, China, epidemiological surveys were conducted on a collaboration basis between the Korean Centers for Disease Control and Prevention and the Yanbian Center for Disease Control and Prevention. A total of 8,396 (males 3,737 and females 4,659) stool samples were collected from 8 localities and examined with the formalin-ether sedimentation technique, and additionally examined with the cellotape anal swab to detect Enterobius vermicularis eggs. The overall rate of intestinal parasites was 1.57%. The prevalence of Ascaris lumbricoides was the highest (0.80%), followed by Entamoeba spp. (0.23%), heterophyid flukes (0.15%), Clonorchis sinensis (0.08%), Enterobius vermicularis (0.07%), hookworms (0.06%), Trichostrongylus spp. (0.06%), Giardia lamblia (0.04%), Paragonimus spp. (0.02%), Diphyllobothrium spp. (0.02%), Trichuris trichiura (0.02%). The prevalence by sex was similar, 1.58% (n=59) in males and 1.57% (n=73) in females. By the present study, it is partly revealed that the prevalences of intestinal parasite infections are relatively low among the inhabitants of Yanbian Prefecture, Jilin Province, China.

Influencing Factors for Cure of Clonorchiasis by Praziquantel Therapy: Infection Burden and CYP3A5 Gene Polymorphism

Chemotherapy of clonorchiasis with praziquantel (PZQ) is effective but about 15% of treated cases have been reported uncured. The present study investigated correlation of single nucleotide polymorphisms (SNPs) of the cytochrome P450 gene, CYP3A5 and cure of clonorchiasis. A total of 346 egg passing residents were subjected and treated by 3 doses of 25 mg/kg PZQ. Reexamination recognized 33 (9.5%) uncured and 313 cured. Numbers of eggs per gram of feces (EPGs) before treatment were significantly lower in the cured group than in the uncured group (2,011.2+/-3,600.0 vs 4,998.5+/-7,012.0, PA and g.27526C>T of CYP3A5 were 15.2% and 9.1% while those were 3.8% and 1.0%, respectively, in the cured group. The cure rate was significantly lower in the cases with SNP at g.27526C>T and EPGs> or =1,000. In conclusion, EPGs and SNPs of CYP3A5 are factors which influence cure of clonorchiasis by PZQ therapy. It is strongly suggested to recommend 2-day medication for individuals with high EPGs> or =1,000.

Single Nucleotide Polymorphisms of Cytokine Genes are Associated with Fibrosis of the Intrahepatic Bile Duct Wall in Human Clonorchiasis

This study examined the association of cytokine gene polymorphisms with intrahepatic bile duct wall fibrosis in human clonorchiasis. A total of 240 residents in Heilongjiang, China underwent ultrasonography, blood sampling, and stool examination. Single nucleotide polymorphism (SNP) sites for IFN-gamma (+874 T/A), IL-10 (-1,082 G/A, -819 C/T, -592 C/A), TNF-alpha (-308 G/A), and TGF-beta1 (codon 10 T/C, codon 25 G/C) genes were observed with the TaqMan allelic discrimination assay. No significant correlation was observed between individual cytokine gene polymorphisms and intrahepatic duct dilatation (IHDD). Among individuals with clonorchiasis of moderate intensity, the incidence of IHDD was high in those with IFN-gamma intermediate-producing genotype, +874AT (80.0%, P = 0.177), and in those with TNF-alpha low-producing genotype, -308GG (63.0%, P = 0.148). According to the combination of IFN-gamma and TNF-alpha genotypes, the risks for IHDD could be stratified into high (intermediate-producing IFN-gamma and low producing TNF-alpha), moderate, and low (low-producing IFN-gamma and high producing TNF-alpha) risk groups. The incidence of IHDD was significantly different among these groups (P = 0.022): 88.9% (odds ratio, OR = 24.0) in high, 56.5% (OR = 3.9) in moderate, and 25.0% (OR = 1) in low risk groups. SNP of IFN-gamma and TNF-alpha genes may contribute to the modulation of fibrosis in the intrahepatic bile duct wall in clonorchiasis patients.

Changing Patterns of Serum and Bile Antibodies in Re-infected Rats with Clonorchis sinensis

Rats develop strong resistance to re-infection and super-infection by Clonorchis sinensis. The present study investigated the antibodies present in the sera and bile juice of rats that were primary infected and re-infected with C. sinensis. The serum level of specific IgG antibodies, which were elevated 2 wk of the primary infection, peaked at 4 wk and subsequently remained unchanged even during re-infection. The total IgE level in serum increased slowly from 388 ng / ml to 3,426 ng / ml beginning 2 wk after the primary infection, and remained high up to 8 wk but dropped to a normal level (259 ng / ml) after treatment. In resistant re-infected rats, the serum IgE level increased rapidly and peaked within 1 wk, whereas no increase was observed in immunosuppressed rats. The serum level of specific IgA antibodies was elevated beginning 1 wk after infection, and decreased 4 wk after treatment. The total bile IgA level unchanged during the primary infection but increased in treated and re-infected rats. The elevated levels of serum IgE and bile IgA indicate that these immunoglobulins may be correlated with the development of resistance to re-infection by C. sinensis in rats.

Changing Patterns of Serum and Bile Antibodies in Re-infected Rats with Clonorchis sinensis

Rats develop strong resistance to re-infection and super-infection by Clonorchis sinensis. The present study investigated the antibodies present in the sera and bile juice of rats that were primary infected and re-infected with C. sinensis. The serum level of specific IgG antibodies, which were elevated 2 wk of the primary infection, peaked at 4 wk and subsequently remained unchanged even during re-infection. The total IgE level in serum increased slowly from 388 ng / ml to 3,426 ng / ml beginning 2 wk after the primary infection, and remained high up to 8 wk but dropped to a normal level (259 ng / ml) after treatment. In resistant re-infected rats, the serum IgE level increased rapidly and peaked within 1 wk, whereas no increase was observed in immunosuppressed rats. The serum level of specific IgA antibodies was elevated beginning 1 wk after infection, and decreased 4 wk after treatment. The total bile IgA level unchanged during the primary infection but increased in treated and re-infected rats. The elevated levels of serum IgE and bile IgA indicate that these immunoglobulins may be correlated with the development of resistance to re-infection by C. sinensis in rats.

Keratitis by Acanthamoeba triangularis: Report of Cases and Characterization of Isolates

Three Acanthamoeba isolates (KA/E9, KA/E17, and KA/E23) from patients with keratitis were identified as Acanthamoeba triangularis by analysis of their molecular characteristics, a species not previously recognized to be a corneal pathogen. Epidemiologic significance of A. triangularis as a keratopathogen in Korea has been discussed. Morphologic features of Acanthamoeba cysts were examined under a microscope with differential interference contrast (DIC) optics. Mitochondrial DNA (mtDNA) of the ocular isolates KA/E9, KA/E17, and KA/E23 were digested with restriction enzymes, and the restriction patterns were compared with those of reference strains. Complete nuclear 18S and mitochondrial (mt) 16S rDNA sequences were subjected to phylogenetic analysis and species identification. mtDNA RFLP of 3 isolates showed very similar patterns to those of SH621, the type strain of A. triangularis. 16S and 18S rDNA sequence analysis confirmed 3 isolates to be A. triangularis. 18S rDNA sequence differences of the isolates were 1.3% to 1.6% and those of 16S rDNA, 0.4% to 0.9% from A. triangularis SH621. To the best of our knowledge, this is the first report, confirmed by 18S and 16S rDNA sequence analysis, of keratitis caused by A. triangularis of which the type strain was isolated from human feces. Six isolates of A. triangularis had been reported from contaminated contact lens cases in southeastern Korea.

A case of sparganosis mimicking a varicose vein

Recent advances in radiological and serological techniques have enabled easier preoperative diagnosis of sparganosis. However, due to scarcity of cases, sparganosis has been often regarded as a disease of other etiologic origin unless the parasite is confirmed in the lesion. We experienced a case of sparganosis mimicking a varicose vein in terms of clinical manifestations and radiological findings. Sparganosis should be included among the list of differential diagnosis with the varicose vein.

Organ-specific antigens of Clonorchis sinensis

This study was carried out to find out specific proteins from different organs of Clonorchis sinensis. Crude extract, organ-specific and excretory-secretory (ES) proteins were analyzed by immunoblot with infected human sera. The bands of 7- and 17-kDa were main component of intestinal fluid and ES protein and commonly found in all organspecific proteins. The 17-kDa protein was observed from ES antigen, intestinal fluid, eggs and sperms, 26- and 28- kDa proteins were from the uterus, vitellaria, and ovary, and 34-, 37-, 43- and 50-kDa proteins were mainly from the testis and sperms. Serum of mice immunized with sperms reacted to the 50-kDa protein by immunoblotting and immunohistochemical staining showed a positive reaction at the seminal receptacle and seminiferous tubule. The present results show that the 7-kDa protein is a common antigen of every part or organ of C. sinensis, but different organs express their specific antigenic protein bands.

Bile duct changes in rats reinfected with Clonorchis sinensis

This study describes an evaluation of the sonographic, cholangiographic, pathological, and immunological findings, and the protective effect shown by rats reinfected with Clonorchis sinensis. Eight experimental rat groups were, namely, a normal control, a primary infection control, a reinfection I (reinfection 7 week after treatment following 3-week infection), a reinfection II (reinfection 2 week after treatment following 8-week infection), a reinfection III (exploration of the intrahepatic bile ducts 1 week after reinfection 4 week after treatment following 4-week infection), a superinfection, a secondary infection control, and an infection following immunization group. Sonographic and cholangiographic findings showed moderate or marked dilatation of the bile duct confluence in the primary infection control, reinfection II, and secondary infection control groups. Juvenile worms survived in the intrahepatic bile ducts 1 week after reinfection following treatment in the reinfection III group. It was concluded that reinfecting juvenile worms found during the first week following reinfection failed to survive or grow further. Anatomical, pathophysiological, or immunological changes may induce protection from reinfection in rats.

Development of resistance to reinfection by Clonorchis sinensis in rats

We investigated the induction of resistance to Clonorchis sinensis infection by prior infection in rat and hamster models. Animals were challenged with C. sinensis metacercariae, then treated with praziquantel and reinfected. Worm recovery rate in reinfected animals was used to estimate resistance to reinfection. The determined resistance rates to reinfection in rats and hamsters were 97.7% and 10.3%, respectively. In rats, cure from the primary infection of C. sinensis increased resistant to reinfection, and the greatert the worm burden and the longer the duration of primary infection, the higher was the resistance rate. For primary infection doses of 10, 40 and 100 metacercariae per rat, the resistance rates were 87.4%, 93.8% and 98.4%, respectively. The resistance rates in rats after 2 or 8-week primary infection were 78.7% and 95.3%, respectively. All worms recovered from reinfected rats were immature. When cured rats were administered with methylprednisolone, resistance to reinfection became impaired. These findings indicate that rats develop a high degree of resistance to reinfection by C. sinensis after cure. The growths and maturations of reinfected worms were also impaired.

Specific and common antigens of Clonorchis sinensis and Opisthorchis viverrini (Opisthorchidae, Trematoda)

The antigenic characterizations and serological reactions of human liver flukes, Clonorchis sinensis and Opisthorchis viverrini, were analyzed by immunoblot. The antigenic profiles of the crude extract of Clonorchis contained major proteins of 8, 26-28, 34-37, 43, and 70 kDa, and those of Opisthorchis 34-37, 43, 70, and 100 kDa. Of these, the 8, 26-28 and 34-37 kDa bands of Clonorchis and the 100 kDa of Opisthorchis were major components of each excretory-secretory antigen. The 8 and 26-28 kDa bands were specific to Clonorchis but the 100 kDa of Opisthorchis cross-reacted with the sera of clonorchiasis, and the 34-37, 70 and 100 kDa bands cross-reacted with sera of other helminthiases. The frequency and intensity of the immunoblot reactions were positively correlated with the intensity of the liver fluke infection.

Characterization of partially purified 8 kDa antigenic protein of Clonorchis sinensis

The 8 kDa antigenic protein of Clonorchis sinensis was partially purified by ammonium sulfate precipitation and subsequently by a column chromatographic steps. The purified protein was separated into 7 and 8 kDa protein bands through SDS-tricine gel electrophoresis, while the protein was found to migrate to a 8 kDa band in 7.5-15% SDS-PAGE. The molecular weight of the antigen was estimated to be 110 kDa by Superose 6 HR 10/30 gel filtration. The purified antigen strongly reacted with the human sera of clonorchiasis. The hyperimmune sera of BALB/c mice immunized against the 8 kDa protein were reacted with both the crude extract and the excretory-secretory product of adult worms, but not with the metacercarial extract. Immunohistochemical staining demonstrated that the protein was distributed to the tegument and subtegumental cells and also to the seminal receptacle. The present findings suggest that the 8 kDa protein is a partition of the multicomplex protein originating from various organs of adult C. sinensis, and that it is composed of several 7 and 8 kDa proteins.