Characterization of Trichuris trichiura from humans and T. suis from pigs in China using internal transcribed spacers of nuclear ribosomal DNA.

Trichuris trichiura and Trichuris suis parasitize (at the adult stage) the caeca of humans and pigs, respectively, causing trichuriasis. Despite these parasites being of human and animal health significance, causing considerable socio-economic losses globally, little is known of the molecular characteristics of T. trichiura and T. suis from China. In the present study, the entire first and second internal transcribed spacer (ITS-1 and ITS-2) regions of nuclear ribosomal DNA (rDNA) of T. trichiura and T. suis from China were amplified by polymerase chain reaction (PCR), the representative amplicons were cloned and sequenced, and sequence variation in the ITS rDNA was examined. The ITS rDNA sequences for the T. trichiura and T. suis samples were 1222-1267 bp and 1339-1353 bp in length, respectively. Sequence analysis revealed that the ITS-1, 5.8S and ITS-2 rDNAs of both whipworms were 600-627 bp and 655-661 bp, 154 bp, and 468-486 bp and 530-538 bp in size, respectively. Sequence variation in ITS rDNA within and among T. trichiura and T. suis was examined. Excluding nucleotide variations in the simple sequence repeats, the intra-species sequence variation in the ITS-1 was 0.2-1.7% within T. trichiura, and 0-1.5% within T. suis. For ITS-2 rDNA, the intra-species sequence variation was 0-1.3% within T. trichiura and 0.2-1.7% within T. suis. The inter-species sequence differences between the two whipworms were 60.7-65.3% for ITS-1 and 59.3-61.5% for ITS-2. These results demonstrated that the ITS rDNA sequences provide additional genetic markers for the characterization and differentiation of the two whipworms. These data should be useful for studying the epidemiology and population genetics of T. trichiura and T. suis, as well as for the diagnosis of trichuriasis in humans and pigs.

Comparative characterization of microRNA profiles of different genotypes of Toxoplasma gondii.

The present study compared the miRNA expression profiles of five Toxoplasma gondii strains, namely RH (Type I, ToxoDB10), TgXD (Type I, ToxoDB10), PRU (Type II, ToxoDB1), QHO (Type II, ToxoDB1) and TgC7 (ToxoDB9), by Solexa deep sequencing, bioinformatics analysis and real-time quantitative PCR. A total of 7, 15, 10, 12 and 10 miRNAs were found from RH, TgXD, PRU, QHO and TgC7 strains, respectively. Thirteen miRNAs were shared by three genotypes, with only one miRNA shared by all of the 5 strains and others shared by 2 or more strains. A large number of targets ranging from 1 to 185 were identified for commonly shared miRNAs and strain-specific miRNAs with complete or nearly complete complementarity. Functional prediction showed that these targets were mostly focused on catalytic activity (191 targets) and binding activity (183 targets). Nonetheless, the majority of targets and most of the miRNAs are related to the virulence or invasion proteins of different strains of T. gondii, including ROP and MIC, as well as some other proteins, such as AMA1, GRA and RHO. The present study characterized comparatively the miRNA profiles of 3 different genotypes of T. gondii, identified genotype-shared miRNAs and strain-specific miRNAs.

Sequence variation in three mitochondrial DNA genes among isolates of Ascaridia galli originating from Guangdong, Hunan and Yunnan provinces, China.

The present study examined sequence variation in three mitochondrial DNA (mtDNA) genes, namely cytochrome c oxidase subunit 3 (cox3) and NADH dehydrogenase subunits 1 and 4 (nad1 and nad4), among Ascaridia galli isolates from different geographical localities in China. A portion of cox3 (pcox3), nad1 (pnad1) and nad4 (pnad4) genes were amplified by polymerase chain reaction (PCR) separately from adult A. galli individuals and the amplicons were subjected to sequencing from both directions. The length of the sequences of pcox3, pnad1 and pnad4 were 408 bp, 471 bp and 333 bp, respectively. The intraspecific sequence variations within A. galli were 0-1.7% for pcox3, 0-2.8% for pnad1 and 0-3.4% for pnad4. The A+T contents of the sequences were 67.16-67.65% (pcox3), 67.09-67.94% (pnad1) and 69.91-71.77% (pnad4). The interspecific sequence differences among members of the Ascaridida were significantly higher, being 13.2-30.9%, 12.8-29.0% and 15.1-34.1% for pcox3, pnad1 and pnad4, respectively. Phylogenetic analyses using combined sequences of pcox3, pnad1 and pnad4, with three different computational algorithms (Bayesian analysis, maximum likelihood and maximum parsimony), all revealed distinct groups with high statistical support. These findings demonstrated the existence of intraspecific variation in mitochondrial DNA (mtDNA) sequences among A. galli isolates from different geographical regions in China, and have implications for studying molecular epidemiology and population genetics of A. galli.

Sequences and gene organization of the mitochondrial genomes of the liver flukes Opisthorchis viverrini and Clonorchis sinensis (Trematoda).

Opisthorchis viverrini and Clonorchis sinensis are important trematodes infecting humans and animals, belonging to the family Opisthorchiidae. In the present study, we sequenced the nearly complete mitochondrial (mt) DNA (mtDNA) sequences of O. viverrini from Laos, obtained the complete mtDNA sequences of C. sinensis from China and Korea, and revealed their gene annotations and genome organizations. The mtDNA sequences of O. viverrini, C. sinensis (China isolate), C. sinensis (Korea isolate) were 13,510, 13,879, and 13,877 bp in size, respectively. Each of the three mt genomes comprises 36 genes, consisting of 12 genes coding for proteins, two genes for rRNA, and 20 genes (O. viverrini) or 22 genes (C. sinensis) for tRNA. The gene content and arrangement are identical to that of Fasciola hepatica, and Paragonimus westermani, but distinct from Schistosoma spp. All genes are transcribed in the same direction and have a nucleotide composition high in T. The contents of A + T of the mt genomes were 59.39% for O. viverrini, 60.03% for C. sinensis (China isolate), and 59.99% for C. sinensis (Korea isolate). Phylogenetic analyses using concatenated amino acid sequences of the 12 protein-coding genes, with three different computational algorithms [maximum parsimony, maximum likelihood, and Bayesian analysis], all revealed distinct groups with high statistical support, indicating that O. viverrini and C. sinensis represent sister taxa. These data provide additional novel mtDNA markers for studying the molecular epidemiology and population genetics of the two liver flukes and should have implications for the molecular diagnosis, prevention, and control of opisthorchiasis and clonorchiasis in humans and animals.

The second transcribed spacer rDNA sequence: an effective genetic marker for inter-species phylogenetic analysis of trematodes in the order Strigeata.

In the present study, the second nuclear internal transcribed spacer (ITS-2) rDNA of Schistosoma japonicum isolates in mainland China was amplified, sequenced, and assessed for inferring the intra- and inter-species phylogenetic relationships of trematodes in the order Strigeata. The fragment containing ITS-2 rDNA was obtained from 24 S. japonicum isolates from eight epidemic provinces in mainland China. The length polymorphisms were observed among these ITS-2 rDNA sequences, ranging from 343 to 346 bp, and the intra- and inter-population variations in ITS-2 sequence were 0.0-2.1% among S. japonicum isolates in China. Phylogenetic analyses using the maximum parsimony and maximum likelihood methods revealed that the ITS-2 rDNA sequence is not a suitable marker for studying inter- and intra-population variation in S. japonicum. However, phylogenetic analysis of trematodes in the order Strigeata indicated that the ITS-2 rDNA sequence provides an effective molecular marker for studying inter-species phylogenetic relationships among trematodes in this order.

Genetic variation among Clonorchis sinensis isolates from different geographic regions in China revealed by sequence analyses of four mitochondrial genes.

The present study examined sequence variation in four mitochondrial (mt) genes, namely cytochrome c oxidase subunits 1 (cox1) and 2 (cox2), and NADH dehydrogenase subunits 1 and 2 (nad1 and nad2) among Clonorchis sinensis isolates from different endemic regions in China, and their phylogenetic relationships with other zoonotic trematodes were reconstructed. A portion of the cox1 and cox2 genes (pcox1 and pcox2), and nad1 and nad2 genes (pnad1 and pnad2) were amplified separately from individual liver flukes by polymerase chain reaction (PCR) and the amplicons were subjected to sequencing from both directions. The intra-specific sequence variations within C. sinensis were 0-1.6% for pcox1, 0-1.4% for pcox2, 0-0.9% for pnad1 and 0-1.0% for pnad2. Phylogenetic analyses based on the combined sequences of pcox1, pcox2, pnad1 and pnad2 revealed that all the C. sinensis isolates grouped together and were closely related to Opisthorchis felineus. These findings revealed the existence of intra-specific variation in mitochondrial DNA (mtDNA) sequences among C. sinensis isolates from different geographic regions, and demonstrated that mtDNA sequences provide reliable genetic markers for phylogenetic studies of zoonotic trematodes.

Sequence variability in two mitochondrial DNA regions and internal transcribed spacer among three cestodes infecting animals and humans from China.

Sequence variability in two mitochondrial DNA (mtDNA) regions, namely cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 4 (nad4), and internal transcribed spacer (ITS) of rDNA among and within three cestodes, Spirometra erinaceieuropaei, Taenia multiceps and Taenia hydatigena, from different geographical origins in China was examined. A portion of the cox1 (pcox1), nad4 genes (pnad4) and the ITS (ITS1+5.8S rDNA+ITS2) were amplified separately from individual cestodes by polymerase chain reaction (PCR). Representative amplicons were subjected to sequencing in order to estimate sequence variability. While the intra-specific sequence variations within each of the tapeworm species were 0-0.7% for pcox1, 0-1.7% for pnad4 and 0.1-3.6% for ITS, the inter-specific sequence differences were significantly higher, being 12.1-17.6%, 18.7-26.2% and 31-75.5% for pcox1, pnad4 and ITS, respectively. Phylogenetic analyses based on the pcox1 sequence data revealed that T. multiceps and T. hydatigena were more closely related to the other members of the Taenia genus, and S. erinaceieuropaei was more closely related to the other members of the Spirometra genus. These findings demonstrated clearly the usefulness of mtDNA and rDNA sequences for population genetic studies of these cestodes of socio-economic importance.

Modulation of mouse macrophage proteome induced by Toxoplasma gondii tachyzoites in vivo.

Toxoplasma gondii is an obligate intracellular protozoan parasite, which can invade and multiply within the macrophages of humans and most warm-blooded animals. Macrophages are important effector cells for the control and killing of intracellular T. gondii, and they may also serve as long-term host cells for the replication and survival of the parasite. In the present study, we explored the proteomic profile of macrophages of the specific pathogen-free Kunming mice at 24 h after infection with tachyzoites of the virulent T. gondii RH strain using two-dimensional gel electrophoresis combined with matrix-assisted laser desorption ionization time-of-flight (TOF)/TOF tandem mass spectrometry. Totally, 60 differentially expressed protein spots were identified. Among them, 52 spots corresponded to 38 proteins matching to proteins of the mouse, including actin, enolase, calumenin, vimentin, plastin 2, annexin A1, cathepsin S, arginase-1, arachidonate 12-lipoxygenase, and aminoacylase-1. Functional prediction using Gene Ontology database showed that these proteins were mainly involved in metabolism, structure, protein fate, and immune responses. The findings provided an insight into the interactive relationship between T. gondii and the host macrophages, and will shed new lights on the understanding of molecular mechanisms of T. gondii pathogenesis.

Seroprevalence of Mycoplasma hyopneumoniae in pigs in subtropical southern China.

Enzootic pneumonia caused by Mycoplasma hyopneumoniae is a severe disease of pigs, causing significant economic losses to the pig industry worldwide, including the tropical and subtropical regions. In order to obtain the baseline prevalence of M. hyopneumoniae in pigs from intensive farms in southern China, double-sandwich enzyme-linked immunosorbent assay (ELISA) was used to detect M. hyoneumoniae antibodies in 460 pig serum samples collected from 12 administrative cities in China's southern Guangdong province. According to the proportions of the infected animals, among the 12 intensive farms, only two of them showed no infection of M. hyoneumoniae and the seroprevalence ranged from 0% to 90%, with an averaged prevalence of 45.7%. The highest prevalence was found in breeding boars (68.8%), followed by sows (54.5%). These data showed that the infection of pigs with M. hyopneumoniae is severe, and boars might be more important carriers and transfers of M. hyoneumoniae than sows. Integrated strategies and measures should be taken to control the infection of pigs with M. hyopneumoniae in southern China.

Specific PCR-based assays for the identification of Fasciola species: their development, evaluation and potential usefulness in prevalence surveys.

Among the helminths infecting ruminants in China are three taxa belonging to the genus Fasciola: F. hepatica, F. gigantica and the so-called 'intermediate form' that appears to lie between these two species. Based on the sequences of the second internal-transcribed spacers (ITS-2) within the parasites' nuclear ribosomal DNA (rDNA), a pair of primers (DSJf/DSJ3) specific for F. hepatica and a pair (DSJf/DSJ4) specific for F. gigantica were designed and used to develop PCR-based assays. These assays allowed the identification and differentiation of F. hepatica, F. gigantica and the 'intermediate' Fasciola, with no amplicons produced from heterologous DNA samples. The results of sequencing confirmed the species-specific identity of the amplified products. The assays showed good sensitivity, giving positive results with as little as 0.11 ng of F. hepatica DNA and 0.35 ng of F. gigantica DNA. This meant that the DNA from a single Fasciola egg or a single infected snail was sufficient for identification of the Fasciola taxon. The developed PCR assays could provide useful tools for the detection, identification and epidemiological investigation of Fasciola infection in humans, other mammals and snails.

RNAi-mediated silencing of a novel Ascaris suum gene expression in infective larvae.

In the present study, the potential of RNA interference (RNAi) as a gene silencing tool and the resultant effects on Ascaris suum larval development was examined by targeting a gene (represented by the EST 06G09) specifically expressed in the infective larvae of A. suum. BALB/c mice were infected with RNAi-treated larvae. The results showed that the target gene was silenced after soaking for 72 h, and the survival rate of the RNAi-treated larvae was reduced by 17.25% (P<0.01). A significant difference (P<0.05) was detected in the numbers of larvae collected from the livers and lungs of infected mice 4 days after infection with untreated larvae (164.29 ± 21.51) and RNAi-treated larvae (71.43 ± 14.35). Significant differences (P<0.01) were also found in the body length and width between untreated larvae (480 ± 105.77 µm for length and 23.93 ± 3.72 µm for width) and RNAi-treated larvae (400.57 ± 71.31 µm for length and 20.20 ± 2.43 µm for width). These results show that the gene represented by EST 06G09 may play a role in the development of A. suum larvae.

Toxoplasma gondii microneme protein 8 (MIC8) is a potential vaccine candidate against toxoplasmosis.

Microneme protein 8 (MIC8) is considered a new essential invasion factor in Toxoplasma gondii. In the present study, a deoxyribonucleic acid vaccine expressing MIC8 of T. gondii was constructed and the immune response it induced in Kunming mice was evaluated. The gene sequence encoding MIC8 was inserted into the eukaryotic expression vector pVAX I, and the pVAX-MIC8 expression plasmid was constructed, and the plasmid diluted with PBS to 100 mg/100 microl was injected into the Kunming mice muscularly. Levels of IgG antibody, gamma-interferon (IFN-gamma), interleukin-2 (IL-2), interleukin-4, and interleukin-10 were detected. The mice were challenged with tachyzoites of the virulent T. gondii RH strain at the 14th day after the last immunization to observe the survival time. The high level of IFN-gamma, IL-2, and IgG antibody indicated that mice vaccinated with recombinant pVAX-MIC8 plasmid could elicit strong cellular and humoral immune responses and showed a significantly increased survival time (10.3 +/- 0.9 days) compared with control mice which died within 5 days of challenge infection. These data demonstrate that the T. gondii MIC8 is a potential vaccine candidate against toxoplasmosis.

Combined mitochondrial 16S and 12S rDNA sequences: an effective genetic marker for inter-species phylogenetic analysis of zoonotic trematodes.

The present study studied the genetic variation among Schistosoma japonicum isolates from different endemic regions in mainland China and examined the phylogenetic relationships of zoonotic trematodes using the combined mitochondrial 16S and 12S ribosomal DNA sequences. The fragments of 16S and 12S rDNA were amplified from 22 S. japonicum isolates, and sequenced, and the relevant sequences of other nine trematode species belonging to six genera in four families were downloaded from GenBank, and their phylogenetic relationships were re-constructed by unweighted pair-group method with arithmetic averages analyses using the combined 16S and 12S rDNA sequences, with Trichinella spiralis as outgroup. The results showed that the partial sequences of mitochondrial 16S and 12S rDNA of S. japonicum were 757 and 797 bp, respectively, and they were quite conserved among the S. japonicum isolates. Phylogenetic analysis revealed that the combined 16S and 12S rDNA sequences were not able to distinguish S. japonicum isolates in mountainous areas from those in lake/marshland areas in mainland China. However, the combined sequences could distinguish different species of zoonotic trematodes. Therefore, the combined mitochondrial 16S and 12S rDNA sequences provide an effective molecular marker for the inter-species phylogenetic analysis and differential identification of zoonotic trematodes.

The detection of "Candidatus Mycoplasma haemobos" in cattle and buffalo in China.

"Candidatus Mycoplasma haemobos" is a hemoplasma species found in cattle and has been recently reported in Switzerland and Japan. In this study, "Candidatus Mycoplasma haemobos" was shown to occur in cattle and buffalo in tropical China by PCR amplification and sequence analysis of the 16S rRNA gene from blood samples. Based on the 16S rDNA sequence, a specific PCR assay was developed. Occurrence of "Candidatus Mycoplasma haemobos" in cattle and buffalo in Guangxi, China, was determined by examining 25 buffalo blood samples, 12 yellow cattle blood samples and 42 dairy cow blood samples. The results showed that 32% (8/25) of buffalo, 41.7% (5/12) of yellow cattle, and 14.3% (6/42) of dairy cows were positive for "Candidatus Mycoplasma haemobos", respectively. Direct sequencing of representative PCR products confirmed that the amplified partial 16S rDNA sequence represented "Candidatus Mycoplasma haemobos". This is the first report of "Candidatus Mycoplasma haemobos" in buffalo, yellow cattle, and dairy cows in China.

Molluscicidal activity of the plant Eupatorium adenophorum against Oncomelania hupensis, the intermediate host snail of Schistosoma japonicum.

The potential molluscicidal activities of aqueous extracts of Eupatorium adenophorum have recently been evaluated against Oncomelania hupensis, the intermediate host snail of Schistosoma japonicum. The snails were continuously exposed to extracts of the leaves, roots or stems [each at concentrations of 0.27%, 0.50% and 0.86% (w/v)], with survival recorded 6, 12, 24, 30, 36, 48, 52, 58, 70, 76, 82 and 96 h after the start of the exposure. Even at the lowest concentration tested (0.27%), the leaf extract caused mortality in excess of 50% after 58 h and 100% mortality after 82 h. This extract was significantly more effective against O. hupensis than the stem or root extract (P<0.05) but there was no statistically significant difference between the root and stem extracts in their molluscicidal effects (P>0.05). These preliminary results indicate that E. adenophorum may potentially provide a new molluscicide that could give effective and environmentally-friendly control of schistosomiasis in humans and livestock. The toxicity of E. adenophorum extracts, or molluscicidal compounds isolated from such extracts, to other snail hosts of human parasites and to non-target species of aquatic life will be investigated.

Severe infection of adult dogs with helminths in Hunan Province, China poses significant public health concerns.

The prevalence of helminths in adult dogs was investigated in Hunan Province, the People's Republic of China between June 2006 and December 2007. A total of 438 adult farm dogs slaughtered in local abattoirs from 9 representative administrative regions in Hunan Province were examined for the presence of helminths using a helminthological approach. All collected worms were counted and identified to species according to existing keys and descriptions. A total of 11 helminth species were found in the dogs, and they represented 2 phyla, 3 classes, 6 families and 8 genera. All dogs were infected by more than one helminth species. Clonorchis sinensis (29.4%) was the only trematode species found, Dipylidium caninum (42.3%) was the most common cestode species, and Toxocara canis (45.2%) the most common nematode species. 6 of the 11 dog helminths are also transmissible to humans (i.e., zoonotic), and can cause severe clinical human diseases, posing significant public health threats. The results of the present investigation have implications for the ongoing control of helminth infections in dogs and humans in Hunan Province, China.

Genetic variability among Schistosoma japonicum isolates from different endemic regions in China revealed by sequences of three mitochondrial DNA genes.

The present study examined sequence variation in three mitochondrial DNA (mtDNA) regions, namely cytochrome c oxidase subunit 3 (cox3), NADH dehydrogenase subunits 4 and 5 (nad4 and nad5), among Schistosoma japonicum isolates from different endemic regions in China, and their phylogenetic relationships were re-constructed. A portion of the cox3 gene (pcox3), a portion of the nad4 and nad5 genes (pnad4 and pnad5) were amplified separately from individual trematodes by polymerase chain reaction (PCR) and the amplicons were subjected to direct sequencing. In the mountainous areas, sequence variations between parasites from Yunnan and those from Sichuan were 0.3% for pcox3, 0.0-0.1% for pnad4, and 0.0-0.2% for pnad5. In the lake/marshland areas, sequence variations between male and female parasites among different geographical locations were 0.0-0.3% for pcox3, 0.0-0.7% for pnad4, and 0.0-1.6% for pnad5. Sequence variations between S. japonicum from mountainous areas and those from lake/marshland areas were 0.0-0.5% for pcox3, 0.0-0.7% for pnad4, and 0.0-1.6% for pnad5. Phylogenetic analyses based on the combined sequences of pcox3, pnad4 and pnad5 revealed that S. japonicum isolates from mountainous areas (Yunnan and Sichuan provinces) clustered together. For isolates from the lake/marshland areas, isolates from Anhui and Jiangsu provinces clustered together and was sister to samples from Jiangxi province, while isolates from Hubei and Zhejiang province clustered together. However, isolates from different geographical locations in Hunan province were in different clades. These findings demonstrated the usefulness and attributes of the three mtDNA sequences for population genetic studies of S. japonicum, and have implications for studying population biology, molecular epidemiology, and genetic structure of S. japonicum, as well as for the effective control of schistosomiasis.

Molecular characterization of hard and soft ticks from Romania by sequences of the internal transcribed spacers of ribosomal DNA.

In the present study, four hard tick species and one soft tick species, namely, Dermacentor marginatus, Haemaphysalis punctata, Haemaphysalis parva, Ixodes ricinus, and Dermanyssus gallinae, from south-western Romania were characterized genetically by the first (ITS-1) and second (ITS-2) internal transcribed spacers (ITS) of nuclear ribosomal DNA (rDNA), using a hard tick, Haemaphysalis longicornis, from China for comparative purposes. The ITS rDNA was amplified by polymerase chain reaction (PCR) and sequenced from individual ticks. The lengths of the ITS-1 sequences were 238-1819 bp, and the lengths of ITS-2 were 137-1695 bp, respectively, for all ticks sequenced. While sequence variation within a hard tick species was 0-1.5%, nucleotide differences between hard tick species ranged 2-25.2%, indicating that ITS rDNA sequences provide genetic markers for the differentiation of hard ticks from Romania. Hence, a PCR-linked restriction fragment length polymorphism approach was developed for their unequivocal differentiation based on ITS-1 rDNA. This is the first characterization of ticks from Romania using a genetic approach, which provides the foundation for further studies on ticks in Romania and has implications for studying the population genetic structure of the Romanian ticks and for identification and differentiation of closely related ticks.

Heterogeneity of class I and class II MHC sequences in Schistosoma japonicum from different endemic regions in mainland China.

The present study examined sequence variation in class I and class II major histocompatibility complex (MHC) genes among Schistosoma japonicum isolates from different endemic regions in mainland China and assessed the level of horizontal gene transfer and sequence similarity between parasites and their hosts. S. japonicum cercariae were used to infect male adult rabbits to obtain adult S. japonicum samples. A portion of the class I MHC gene (pMHC I) and class II MHC genes (pMHC II) were amplified separately from individual adult trematodes by polymerase chain reaction and sequenced. Among all the examined isolates of S. japonicum, sequence differences between male and female parasites were 0.0-26.6% for pMHC I and 0.0-7.0% for pMHC II. Sequence variations between male and female parasites among different geographical locations from the mountainous areas were 1.1-26.6% for pMHC I and 1.5-3.0% for pMHC II. Sequence variations between samples from Yunnan and those from Sichuan were 2.7-23.5% for pMHC I and 1.1-3.7% for pMHC II. In the lake/marshland areas, sequence variations between male and female parasites among different geographical locations were 0.0-25.0% for pMHC I and 0.0-7.0% for pMHC II. Sequence variations between S. japonicum isolates from mountainous areas, and those from lake/marshland areas were 0.0-26.1% for pMHC I and 0.4-6.1% for pMHC II. BLASTN analysis indicated that all the pMHC II sequences showed high homology to a portion of exon 3 in rabbit MHC class II DP beta gene with more than 89% similarity, and all the pMHC I sequences except isolates in Yunnan (Eryuan) revealed high homology to the portion of exon 2 in rabbit MHC I gene with more than 81% similarity. Phylogenetic analysis showed no specific clustering comprising parasites from single geographical or endemic regions, and the paired parasites were even found in different clusters. These results demonstrated that pMHC I and II of S. japonicum isolates in mainland China existed heterogeneity, but the pMHC I, II, or combined sequences were not suitable markers for examining genetic relationship among different isolates from endemic regions in mainland China.

[Qualitative research on pain experiences of adult burn patients].

Objective: To explore the pain experiences of adult burn patients so as to lay foundation for practical analgesic measures. Methods: Using phenomenological method in qualitative research, semi-structured interviews were conducted on 12 adult burn patients hospitalized in our burn units from May to November 2015, aiming at pain experiences from immediately after burns to 3 to 7 months after being discharged from hospital. Then the Colaizzi's analysis method was applied to analyze, induce, and refine themes of interview data. Results: After analysis, pain experiences of adult burn patients were generalized into 6 themes: deep pain experiences, heavy psychological burden, limited daily life, poor assessment and treatment of pain, different attributions of pain, and different ways of coping of pain. Conclusions: Burn pain brings harm to the patients' physiology, mentality, and daily life. Nevertheless, pain processing modes of medical staff and patients themselves are the key factors affecting patients' pain experiences. Therefore, according to the deficiency of current situation of pain management, the targeted analgesic intervention measures should be carried out from the perspectives of medical staff and patients.