Enterococcus faecalis provides protection during scavenging in carrion crow ( Corvus corone).

The gut microbiota significantly influences host physiology and provides essential ecosystem services. While diet can affect the composition of the gut microbiota, the gut microbiota can also help the host adapt to specific dietary habits. The carrion crow ( Corvus corone), an urban facultative scavenger bird, hosts an abundance of pathogens due to its scavenging behavior. Despite this, carrion crows infrequently exhibit illness, a phenomenon related to their unique physiological adaptability. At present, however, the role of the gut microbiota remains incompletely understood. In this study, we performed a comparative analysis using 16S rRNA amplicon sequencing technology to assess colonic content in carrion crows and 16 other bird species with different diets in Beijing, China. Our findings revealed that the dominant gut microbiota in carrion crows was primarily composed of Proteobacteria (75.51%) and Firmicutes (22.37%). Significant differences were observed in the relative abundance of Enterococcus faecalis among groups, highlighting its potential as a biomarker of facultative scavenging behavior in carrion crows. Subsequently, E. faecalis isolated from carrion crows was transplanted into model mice to explore the protective effects of this bacterial community against Salmonella enterica infection. Results showed that E. faecalis down-regulated the expression of pro-inflammatory cytokines tumor necrosis factor alpha (TNF-α), interferon gamma (IFN-γ), and interleukin 6 (IL-6), prevented S. enterica colonization, and regulated the composition of gut microbiota in mice, thereby modulating the host's immune regulatory capacity. Therefore, E. faecalis exerts immunoregulatory and anti-pathogenic functions in carrion crows engaged in scavenging behavior, offering a representative case of how the gut microbiota contributes to the protection of hosts with specialized diets.

Vector-Borne Pathogens with Veterinary and Public Health Significance in Melophagus ovinus (Sheep Ked) from the Qinghai-Tibet Plateau.

Melophagus ovinus (sheep ked) is a hematophagous ectoparasite that mainly parasitizes sheep. In addition to causing inflammation, wool loss, and skin damage to the animal hosts, M. ovinus also serves as a vector for a variety of pathogens and is highly likely to participate in the life and transmission cycle of pathogenic organisms. Herein, we investigated the presence and molecular characterization of vector-borne pathogens in M. ovinus from Qinghai-Tibet Plateau, China. A total of 92 M. ovinus pools collected from the Qinghai province of China were screened for the presence of selected vector-borne pathogens. The overall positive rate of A. ovis, A. bovis, A. phagocytophilum, and T. ovis in M. ovinus was 39.1%, 17.4%, 9.8%, and 89.1%, respectively. All of the samples were negative for Border disease virus (BDV), other Anaplasma species, Babesia spp., Rickettsia spp., and Borrelia spp. Co-infection of different Anaplasma species and T. ovis occurred in 51.2% of all samples with T. ovis. The positive rates of A. ovis, A. bovis, and A. phagocytophilum in different regions and altitudes of the sampling sites were significantly different. Sequence and phylogenetic analysis of target genes confirmed their identity with corresponding pathogens. Our results elucidate the occurrence and molecular characterization of Anaplasma spp. and Theileria spp. in M. ovinus, which could act as potential zoonotic reservoirs. To the best of our knowledge, this is the first report of the detection of A. bovis and A. phagocytophilum DNA in M. ovinus. This study gives the first extensive molecular survey of vector-borne pathogens with veterinary and public health significance in M. ovinus from the Qinghai-Tibet Plateau, China.

Spotted Fever Group Rickettsia Infecting Ticks (Acari: Ixodidae), Yak (Bos grunniens), and Tibetan Sheep (Ovis aries) in the Qinghai-Tibetan Plateau Area, China.

The Qinghai-Tibet Plateau Area (QTPA) has a complex natural ecosystem, causing a greatly increased risk of spreading various tick-borne diseases including rickettsial infections, which are regarded as one of the oldest known vector-borne zoonoses. However, the information of one of its pathogen, spotted fever group Rickettsia (SFG Rickettsia), is limited in tick vectors and animals in this area. Therefore, this study focused on the investigation of SFG Rickettsia in tick vectors, yaks (Bos grunniens), and Tibetan sheep (Ovis aries) in the QTPA. A total of 1,000 samples were collected from nine sampling sites, including 425 of yaks, 309 of Tibetan sheep, 266 of ticks. By morphological examination, PCR, and sequencing, we confirmed the species of all collected ticks. All tick samples, all yak and Tibetan sheep blood samples were detected based on SFG Rickettsia ompA and sca4 gene. The results showed that all tick samples were identified to be Haemaphysalis qinghaiensis, and the positive rates of SFG Rickettsia were 5.9% (25/425), 0.3% (1/309), and 54.1% (144/266) in yaks, Tibetan sheep, and ticks, respectively. All positive samples were sequenced, and BLASTn analysis of the ompA gene sequences of SFG Rickettsia showed that all positive samples from animals and ticks had 99.04-100% identity with yak and horse isolates from Qinghai Province, China. BLASTn analysis of the sca4 gene sequences of SFG Rickettsia showed that all positive samples had 97.60-98.72% identity with tick isolates from Ukraine. In addition, the phylogenetic analysis showed that all the SFG Rickettsia ompA and sca4 sequences obtained from this study belong to the same clade as Rickettsia raoultii isolated from livestock and ticks from China and other countries. Molecularly, this study detected and characterized SFG Rickettsia both in the tick vectors and animals, suggesting that the relationship between SFG Rickettsia, tick species and animal hosts should be explored to understand their interrelationships, which provide a theoretical basis for preventing control of this pathogen.

First report of Enterocytozoon bieneusi and Cryptosporidium spp. in peafowl (Pavo cristatus) in China.

Enterocytozoon bieneusi and Cryptosporidium spp. are important pathogens causing diarrhea in humans and animals. However, few studies have been conducted on the infection of E. bieneusi and Cryptosporidium spp. in peafowl up to now. The purpose of the present study was to determine the prevalence and the involved genotypes of Cryptosporidium spp. and E. bieneusi in peafowl in Beijing and Jiangxi Province, China. In total, 258 peafowl fecal samples were collected. Overall, both Cryptosporidium spp. and E. bieneusi had the same prevalence, i.e. 6.59% (17/258). Higher infection rates of E. bieneusi and Cryptosporidium spp. were found in the adolescent peafowl. The prevalence of E. bieneusi in Beijing and Jiangxi Province was 5.23% and 8.57% respectively. For Cryptosporidium spp., the prevalence was 4.58% and 9.52% in Beijing and Jiangxi Province, respectively. Three zoonotic genotypes of E. bieneusi were confirmed, including two known genotypes, genotype Peru 6 and D, and one novel genotype, JXP1. Two avian specific species/genotypes of Cryptosporidium, Avian genotype Ⅲ and Goose genotype Ⅰ, were identified. To our knowledge, this is the first report of E. bieneusi and Cryptosporidium spp. occurrence in peafowl in China. The findings suggest that peafowl could be reservoirs of E. bieneusi and Cryptosporidium spp. which could be potentially transmitted to humans and other animals, and the present survey have implications for controlling E. bieneusi and Cryptosporidium spp. infection in peafowl.

Prevalence and molecular characterization of Trichomonas gallinae from domestic pigeons in Beijing, China.

Trichomonas gallinae is a globally distributed protozoan parasite, mainly affect the upper avian digestive tract and can bring huge economic losses to pigeon industry. The objective of the present study was to determine the prevalence and genotypes of T. gallinae in Beijing, China. A total of 569 samples of throat swabs of pigeon were collected from pigeon farms in Shunyi District, Fangshan District, Daxing District and Miyun District of Beijing. The overall prevalence was 28.30%. The significant difference in infection rates was not observed between regions, but was found between age groups. The highest prevalence was nestling pigeons (33.16%), followed by adolescent pigeons (30.05%) and breeding pigeons (20.59%). Moreover, genotype A and B of T. gallinae were identified by sequencing the ITS1/5.8S/ITS2 regions and phylogenetic analysis. To our knowledge, this is the first report to display the prevalence and genotype of T. gallinae from Beijing, China.

Patterns of polymorphism and divergence in the VP1 gene of enterovirus 71 circulating in the Asia-Pacific region between 1994 and 2013.

Enterovirus 71 has been implicated in several outbreaks of hand, foot and mouth disease in the Asia-Pacific region. The present study aimed to achieve comprehensive evolutionary dynamic aspects of EV71 during 1994-2013, based on phylogenetic analyses of the VP1 sequences. The results indicated that 4 genotypes, namely C4, C1, C2 and B4 are the predominant strains, especially in Southeast Asian countries. No common ancestor was shared in different countries. Fourteen sites of substitutions were detected in the VP1 gene sequences; including the most common sites related to neutralization at position V249I [47.1% (189/401)] and A289T [42.6% (171/401)]. However, the sites Q22H and Q22R associated with increased virulence were recognized only in 13.7% (55/401) and 18% (72/401), respectively. None of the above mutations seemed to become fixed because the ratio of Ka/Ks was greater than 1.0. Mutations K43E, A58T, S184T, and T240S could possibly change the spatial structure. Two mutations, G145E and T240S, could obviously affect the hydrophobicity of VP1 and thus alter the EV71 immunoreactivity. In conclusion, the VP1 gene of EV71 strains circulating in the Asia-Pacific region during 1994-2013, showed polymorphisms and divergence with very slow evolution rate, which may be one of the reasons for periodic outbreaks in this area.

Pandemic influenza A(H1N1) 2009 virus in pregnancy.

Two hundred fourteen abstracts and 87 full texts regarding pregnant women infected with pandemic influenza A(H1N1) 2009 virus were systematically reviewed by using a PubMed search and assessing pandemic, clinical, laboratory test, vaccine, and control experiences. Both policy and health education were excluded. This review counted the total number of pregnant cases from different countries and analyzed their epidemic features, including trimester distribution, morbidity, hospitalization, intensive care unit admissions, maternal mortality, underlying diseases, complications, high-risk factors for death, pregnancy outcome, and clinical symptoms compared with the previous pandemic seasonal influenza A/H1N1 as compared with the general population. Early identification and treatment were the most important factors in different countries and areas examined. The vaccine and antiviral drugs that have been the most efficient means to control the novel virus appear to be safe but require more extensive study. In the future, the focus should be placed on understanding vertical transmission and the severe mechanisms.

[Development of an IMS-qPCR method for detection of Cryptosporidium parvum in water].

OBJECTIVE: To develop a detection method for Cryptosporidium parvum oocysts from water samples, which combined immunomagnetic separation (IMS) with Taqman real-time PCR (qPCR). METHODS: Conditions of separation and enrichment of IMS method by using specific streptavidin magnetic beads coated with monoclonal antibodies Cp23 directed against C. parvum oocysts were optimized. Special primers of PCR and Taqman probes were designed referring to the 18S rDNA gene of C. parvum (GenBank Accession No. AB513881.1). The conserved genes were amplified from genomic DNA of C.parvum, and then cloned into Peasy-T1 vector. Tenfold dilutions of positive plasmids (10(4)-10(8) copy/microl) were used to construct a standard curves by Taqman qPCR. The specificity of the assay was determined using genomic DNA of C. baileyi, Toxoplasma gondii, C. canis and Escherichia coli. The sensitivity of this assay was evaluated by analyzing 10-fold serially dilutions of plasmids ranging from 10(0) to 10(8) copy/microl. Both IMS-qPCR assay and indirect immunofluorescent-antibody assay (IFA) were applied to detect 50 water samples collected from the dairy cattle farms in Hebei. RESULTS: The optimal incubation concentration and time of antibody Cp23 were 20 ng/ml and 30 min, respectively, and the catching time was 30 min, the recovery rate was more than 95%. PCR product was 272 bp, and identified by restriction enzyme digestion and nucleotide sequencing. There was a good linear relationship between the standard plasmids and Ct value (correlation r2 = 0.996 1) of the Taqman qPCR. No cross-reactivity was observed with C. baileyi, T. gondii, C. canis and E. coli. The sensitivity of C. parvum-specific assay was 10 copy/microl. Compared with IFA as golden standard method, the specificity and sensitivity of IMS-qPCR for 50 water samples was 100%(18/18) and 93.8% (30/32), respectively. CONCLUSION: The IMS-qPCR assay can be used to specifically detect C. parvum oocysts in water samples.

[Comparison of three methods in construction fusion gene of influenza A virus Nucleoprotein].

OBJECTIVE: To develop a best method of constructing influenza NP fusion gene containing enhanced green fluorescent protein (EGFP). METHODS: The full-length NP gene of influenza A was amplified by RT-PCR and was inserted into an eukaryotic expression vector pEGFP-N1 in order to construct a fusion gene of pEGFP-N1-NP using three different methods. Method one, NP gene containing restriction endonucleases and pEGFP-N1 were both digested using the same restrict enzymes and ligated, yielding the fusion gene of pEGFP-N1-NP. Method two, NP gene was cloned into pMD19-T Vector to construct a plasmid of pMD19-T-NP. The pMD19-T-NP cloned into pEGFP-N1 to construct the fusion gene of pEGFP-N1-NP; Method three, NP gene containing restriction endonucleases was cloned into pMD19-T Simple Vector to construct a plasmid of pMD19-T-NP. The pMD19-T-NP cloned into pEGFP-N1 to construct the fusion gene of pEGFP-N1-NP. RESULTS: The fusion gene of recombinant eukaryotic expression vector pEGFP-N1-NP was successfully constructed by using method three. CONCLUSIONS: The full-length NP gene is obtained and its fusion gene of recombinant eukaryotic expression plasmid is successfully constructed. This study provides foundation for further understanding the biological function of NP protein and the mechanism of diseases induced by influenza A virus.

Evolutionary characterization of human H1N1 influenza virus hemagglutinin genes isolated from 1947 to 2009 in China.

OBJECTIVE: Our aim was to reveal the molecular characteristics of human H1N1 influenza virus hemagglutinin (HA) genes from 1947 to 2009 in China. METHODS: 129 HA gene sequences were downloaded from NCBI's GenBank and analyzed by DNASTAR software. Additionally, the three-dimensional structure of HA protein was predicted by the SWISS-MODEL service. RESULTS: First, 2009 Chinese HA genes were 99% identical to those of Mexican and American ones; their key sites remained highly conserved. Second, 50 Chinese strains from 1947 to 2009 clustered by the year of isolation, and 2009 strains had only 70% identity to 1947-2008 ones. Third, over the past 60 years, 3 receptor-binding (RB) sites and 2 of the 8 glycosylation sites (amino acids 279 and 290) underwent considerable changes while the cleavage sites remained stable. Fourth, the human HA sequences differed completely from swine and avian isolates. Finally, the mutation of cleavage sites can change the three-dimensional structures, but single mutations cannot. CONCLUSIONS: Thus, in the past 60 years, Chinese H1N1 influenza HA genes kept stable with high affinity and low pathogenicity to human except changes in 2 glycosylation and 3 RB sites which were associated with the pandemic strength, range and host specificity of viruses.

Immune-related gene expression in response to H5N1 avian influenza virus infection in chicken and duck embryonic fibroblasts.

Chicken and ducks are important hosts in responses to highly pathogenic avian influenza virus (HPAIV) H5N1 infection. In ducks, avian influenza (AI) generally causes an asymptomatic and long-lasting infection, whereas clinical apparent and transient disease is often observed in chickens. Using real-time quantitative PCR, we examined the expression of immune-related genes in response to H5N1 infection in chicken embryo fibroblasts (CEF) and duck embryo fibroblasts (DEF). While in CEF IL-6 expressed at high levels similar to mammalian species, in DEF expression levels were minimal. Similarly, duck IFN-ß expression were slightly upregulated, whereas chicken expressions were highly upregulated. Chronologically, the mRNA levels of both IFN-alpha and IFN-gamma, which belong to type I and type II interferon, respectively, were unregulated in a similar fashion in chickens than in ducks. IL-2 and TLR-7 were elevated from the beginning of the infection in both CEF and DEF to the end of the experiment. Chicken MHC class I expression was almost unaffected while duck expression were downregulated. DEF and CEF MHC class II expression were downregulated. Chemokine IL-8 expression was upregulated in both species. The IL-8 levels closely parallel the IL-1ß induced IL-6 levels in the same samples. These results show distinct embryo fibroblasts expression patterns of pro-inflammatory cytokines and IFNs between species.

2009 pandemic characteristics and controlling experiences of influenza H1N1 virus 1 year after the inception in Hangzhou, China.

This paper described the epidemiology and controlling experiences of influenza H1N1 in Hangzhou in the past 1 year. A total of 2,078 cases confirmed by real-time quantitative PCR till March 31, 2010, were analyzed by SPSS 12.0 software. During the early pandemic stage, a patient must be tested for H1N1 nucleic acid once he/she had influenza-like symptoms with the epidemiological history in 7 days, and be diagnosed if it was positive. But in the pandemic peak, we made efforts to identify and save severe cases combined with pneumonia or hypoxemia or respiratory failure or septic shock or multiple organ dysfunctions and failure. In general, the prevalence was 2.77/100,000 (2,078/7,510,844); severity rate, 10.44% (217/2,078); fatality rate, 0.48% (10/2,078). The carrier and secondary attack rate were 9.52% (58/612) and 8.66% (53/612), respectively. About 50% of serious cases and 100% of deaths had the basic underlying diseases: cardiovascular diseases, 13.66% (25/217); chronic lung disease, 12.02% (22/217); pregnant, 7.1% (13/217). Of all cases aged from 1 month to 89 years, 52.99% (1,435/2,708) were in the 10-29 years, with most of them distributed in downtown area. The timeline showed two epidemic peaks occurred in September and November 2009, respectively. Furthermore, the hemagglutinin gene remained 99% identical with the American and vaccine strains, but only 70% with the 1947-2008 Chinese strains. In conclusion, Hangzhou pandemic influenza H1N1 was caused by the highly conserved virus, with low prevalence, transmission, and mortality, because we took efficient controlling methods.

Retrocyclin 2: a new therapy against avian influenza H5N1 virus in vivo and vitro.

We tested the ability of retrocyclin 2, a type of theta defensin, to protect cells and chicken embryos from infection by H5N1 highly pathogenic avian influenza virus. A gene fragment of retrocyclin 2 was designed based on the protein sequence of retrocyclin 2 and cloned into the eukaryotic expression vector pcDNA4.01 (HismaxA), named pcDNA4-RC2. The expression vector pcDNA4-RC2 protected MDCK cells and chicken embryos from infection by the H5N1 virus through inhibition of virus replication and viral mRNA transcription. Retrocyclin 2 is therefore effective in preventing H5N1 virus infection in vivo and in vitro and could be considered as a new therapy for H5N1 influenza and other diseases.

Screening of differentially expressed genes in the hypothalamus of a rat neuropathic pain model following sciatic nerve injury.

BACKGROUND: Neuropathic pain is induced by injury or disease of the nervous system. Most studies have so far focused only on a few known molecules and signaling pathways among neurons. However, all signal transmissions involved in neuropathic pain appear to be an integral system at different molecular levels. This study was designed to screen the differentially expressed genes of the hypothalamus in chronic constriction injury (CCI) rats and analyze their functions in developing neuropathic pain. METHODS: Ten adult female Sprague-Dawley rats ((200 +/- 10) g) were used in experimental group and sham group (n = 5 in each group). Mechanical allodynia tests were performed to ensure that the CCI rat model was constructed successfully. Total hypothalamus RNAs were isolated from each group. Forward suppression subtractive hybridization (SSH) library of rat hypothalamus was constructed and up-regulated cDNA clones at neuropathic pain states were obtained via suppressed subtractive hybridization technique and the functions of these genes were analyzed bioinformatically. RESULTS: Mechanical allodynia tests showed that the experimental rats had a significantly reduced mechanical allodynia threshold 3 to 13 days after CCI vs sham surgery rats (P < 0.01), indicating that the model was successful. Forward SSH library of the rat hypothalamus was constructed successfully and 26 over-expressed expression sequence tags (ESTs) were obtained from these up-regulated cDNA clones. CONCLUSION: Twenty-six up-regulated genes, involved in the regulation of cell cycle and apoptosis, signal transduction, and neuroprotection, may play key roles in decreasing mechanical withdraw thresholds in CCI rats, which implicates a multidimensional and integrated molecular mechanism at gene level in developing neuropathic pain with the supraspinal contributions.

[Preparation and identification of monoclonal antibody against sporozoites of Eimeria acervulina].

OBJECTIVE: To establish hybridoma cell lines against sporozoites of Eimeria acervulina. METHODS: BALB/c mice were immunized with purified sporozoites of E. acervulina. Hybridoma cell lines were set up by using hybridoma technique, and monoclonal antibodies were prepared. The monoclonal antibody was identified by determining their cross reactivity, relative affinity, immunoglobulin class or subclass with enzyme linked immunosorbent assay (ELISA). RESULTS: Four hybridoma cell lines stably secreting McAbs against sporozoites were obtained: Easp-3G3 and Easp-5G10 belonging to IgG1, Easp-3H6 belonging to IgG2b, Easp-5H4 belonging to IgG2a. All four McAbs bound with E. acervulina sporozoite protein, but the Easp-5H4 McAb showed cross reactivity with E. tenellum sporozoite protein. Different antigenic epitopes were recognized by Easp-3G3 or Easp-5G10 and Easp-3H6 or Easp-5H4. CONCLUSION: Three of the four produced monoclonal antibodies show high specificity and affinity to the Eimeria acervulina sporozoites.

Isolation and identification of a new thymic peptide from calf thymus.

Various thymic peptides (including thymulin, thymic humoral factor, thymopoietin, etc.) play important roles in the process of T cell maturation and development. We isolated a new peptide from calf thymus and named it thymus activity factor II (TAF-II). A yield of 0.92 mg of TAF-II was purified from 500 g calf thymus. Analysis by LC/MSD-Trap showed the amino acid sequence of this hexapeptide to be Glu-Ala-Lys-Ser-Gln-Gly-OH with molecular weight 618.5 daltons. We have also begun to investigate the influence of TAF-II.

Expression of gonadotropin-releasing hormone receptor and effect of gonadotropin-releasing hormone analogue on proliferation of cultured gastric smooth muscle cells of rats.

AIM: To investigate the expression of gonadotropin-releasing hormone (GnRH) receptor and the effects of GnRH analog (alarelin) on proliferation of cultured gastric smooth muscle cells (GSMC) of rats. METHODS: Immunohistochemical ABC methods and in situ hybridization methods were used to dectect protein and mRNA expression of GnRH receptor in GSMC, respectively. Techniques of cell culture, OD value of MTT test, measure of (3)H-TdR incorporation, average fluorescent values of proliferating cell nuclear antigen (PCNA) and flow cytometric DNA analysis were used in the experiment. RESULTS: The cultured GSMC of rats showed immunoreactivity for GnRH receptor; positive staining was located in cytoplasm. GnRH receptor mRNA hybridized signals were also detected in cytoplasm. When alarelin (10(-9), 10(-7), 10(-5) mol/L) was administered into the medium and incubated for 24 h, OD value of MTT, (3)H-TdR incorporation and average fluorescent values of PCNA all decreased significantly as compared with the control group (P<0.05). The maximum inhibitory effect on cell proliferation was achieved a concentration of 10(-5) mol/L and it acted in a dose-dependent manner. Flow cytometric DNA analysis revealed that alarelin could significantly enhance ratio of G(1) phase and decrease ratio of S phase of GSMC of rats (P<0.05). The maximum inhibitory effect on ratio of S phase was at the concentration of 10(-5) mol/L and also acted in a dose-dependent manner. CONCLUSION: Our data suggest that GnRH receptor can be expressed by GSMC of rats. GnRH analogue can directly inhibit proliferation and DNA synthesis of rat GSMC through GnRH receptors.

[Cloning of a species-specific gene fragment from Cryptosporidium parvum and the development of diagnostic PCR primers].

OBJECTIVE: To develop a pair of diagnostic PCR primers for Cryptosporidium parvum. METHODS: A species-specific gene fragment of C. parvum was obtained through RAPD analysis. After the fragment was isolated, purified, cloned and sequenced, a pair of primers FF was designed and synthesised based on the sequence. With the primers, the anticipated fragment in size of 603 bp was amplified by PCR from 2 American strains and 4 Chinese strains of C. parvum. The samples of 35 rabbits feces and 55 human feces were detected by PCR with primers FF and 021, the latter was a species-specific diagnostic primer reported by Morgan. RESULTS: All six strains amplified by the primers FF showed same detection rate with 021. Sensitivity test indicated that DNA of 1 oocyst per gram of feces could be detected by the PCR. CONCLUSION: The primers FF showed high specificity and sensitivity, and can be used for diagnosing Crytosporidium parvum infection.

[Cloning and sequencing of the gp23 gene encoding a surface antigen on sporozoites of Cryptosporidium parvum].

OBJECTIVE: To clone and sequence the gp23 gene encoding a surface antigen on the sporozoites of Cryptosporidium parvum. METHODS: Genomic DNA was isolated from oocysts of Cryptosporidium parvum. The gp23 gene was amplified by polymerase chain reaction (PCR) and cloned into pMD18-T vector and sequenced by the methods of dideoxy-mediated chain termination. RESULTS AND CONCLUSION: The gp23 gene was 345 bp in length and included an open reading frame encoding a protein of 114 amino acid residues. The homology of the nucleotide and amino sequences of the gp23 gene was 97.3% and 98.2% to that in the GenBank, respectively. The gp23 gene cloned contained 6 nucleotides more than that in the GenBank.