| The epidemiological investigation of parasites infection status in intensive pig farms in Henan Province was carried out. In order to provide theoretical basis for prevention of cryptosporidiosis,the Cryptosporidium isolates derived from intensive pig farms in Henan Province were identified based on morphologically,Nested PCR detection and PCR-RFLP analysis; genotypic analysis of the Small-Subunit rRNA (SSU rDNA) gene were carried out to indentify species and genotype, to determine molecular phylogenetic relationship between isolates drived from pigs in Henan Province and other species.To understand the parasites infection situation in intensive pig farms,the fecal samples from 1119 pigs (both sexes and five age groups,310 slurries) were studied in 14 representative intensive pig farms employed different parasite control strategies from ten regions in Henan Province using standard techniques from August 2006 to July 2007. It was shown that the total infection rate was 56.21%. 467(41.73%) were infected with coccidia (Eimeria spp. and/or Isospora suis),129(11.53%) with Ascaris suum, 61(5.45%) with Strongyloidesransomi, 106(9.47%) with Balantidium coli,72(6.43%) with Trichuris suis,Cryptosporidium spp. were detected in 127 pig faecal samples from hoggeries by the Sheather's sugar flotation and modified acid-fast staining method.The positive rates of oocyst in stools of 0～1 month old pigs,1～2 month-old pigs,2-6 month old pigs,more than 6 months old pigs and mature boars were 14.0%,23.4%,12.1%,9.8%and 8.8% respectively. Cryptosporidium spp. were not detected in the slurry samples from piggeries in Xinyang and Xuchang.The discrepancy may has items on the geographical areas, which was validated by datas above in the infection rates of Cryptosporidium among various ages and areas.The Cryptosporidium oocysts were identified morphologically as Cryptosporidium suis.Concurrent infection of multiple parasite species was common.The control strategies against intestinal parasitism in intensively raised pigs in Henan Province was provided based on the results of the present investigation. The Small-Subunit rRNA(SSU rRNA) specific fragments of the isolates were amplified by Nested PCR. The PCR products were digested by SspI restriction enzyme and VspI restriction enzyme respevtively to determine species and genotype. Fragments of 454bp and 378bp were got after digested with SspI and fragments of 633 bp and 115bp were got after digested with VspI. Based on length of restriction fragments, the nine isolates were initially considered to be C. suis,cryptosporidium pig genotypeⅡwas not detected.In order to determine species/ genotype of cryptosporidium isolates from pigs in Henan Province, specific fragments of 18S rDNA gene were amplified by nested PCR, cloned and sequenced. Then, Blast or Fasta methods was used to search homological sequences in NCBI, DDBJ and EMBL, after that, homological sequences were alignmented. Phylogenetic tree and homological analysis were made by some biological softwares such as Clustal X 1.81, and DNAstar 4.0. Based on the phylogenetic analysis of 18S rRNA gene, HSP70 gene and actin gene, the nine isolates were idenfied as C.suis,cryptosporidium pig genotypeⅡwere not found.Based on PCR-RFLP and genotypic analysis,the species/ genotype of the isolates in present were reached consensus and identified as C.suis. High prevence and similarity of sequences of cryptosporidium from pigs in other countries show that C.suis is common and not restricted to geographical features.
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