Research On Host Adaptation Of Cryptosporidium Baileyi Derived From Different Host

Cryptosporidiosis is one of the most prevalent parasitic infections in domesticated, caged, and wild birds and the parasite has been reported in more than 30 avian species worldwide。Now, The research indicate that C. baileyi had important public health significance because it can infecte human. C. baileyi is the most primal intestinal tract parasite in our country's poultry industry and can be type species in researching cryptosporidium.It is not reported that whether have the virulence, hereditary capacity and host adaptability of C. baileyi difference after infecting different avian. In this research, C. baileyi oocysts from different avians(chicken, duck, quail, ostrich, pet bird) infected same poultry at the same condition, we studing C. baileyi host adaptability and pathogenicity by comparing clinical symptom of different infected animals. In addition, we take a drug treatment experiment to the chickens infected C. baileyi with the Chinese herbal medicine(Astragalus mongholicus). The result of this study have important significance due to study spread kinesic foundation of cryptosporidium in diversity hosts, predict genetic variance regular, analysis cryptosporidium public health significance and make cryptosporidium study model.In order to study the pathogenicity of cryptosporidium baileyi from two different geographical chickens,3-day-old Roman chickens were inoculated with 1×106 C. baileyi oocysts isolated from Zhengzho and Linzho chickens,which was reproducted in chickens. Oocyst discharge, clinical signs, histopathology and pathomorphology were compared in two groups for evaluate its pathogenicity. The result shown that C. baileyi from two different geographical areas chickens caused mainly respiratory distress and bursa of Fabricius inflammation.These chickens were inoculated began discharging oocyst at PID4,the persistent period of Linzhou and Zhengzhou isolate discharging oocyst was 23 days and 12 days respectively; the crest-time of oocyst discharge were all 5 days from PID8 to PID12. The amount and pattern of oocys shedding were different after chickens were infected with two different geographical Cryptosporidium baileyi.To understand the host adaptation and host-parasite coevolution biology phenotype difference of Cryptosporidium baileyi different avians,10-day-old male Korea LongCheng quail were inoculated with 1×106 C..baileyi oocysts from diversity avians. Oocyst discharge, clinical symptom, index of bursa of Fabricius, histopathology and pathomorphology were compared in two groups for evaluate its pathogenicity. The result shown that two different origin C..baileyi caused mainly respiratory distress and bursa of Fabricius inflammation, The parasite mainly parasitized throat, trachea, cloaca and bursa of Fabricius of infected chickens.The clinical symptom,amount and pattern of oocys shedding, index of bursa of Fabricius were different after chickens were infected with two different origin Cryptosporidium baileyi. Three diffreernt does of Astragali seu Hedysari Decoction were used to treat chickens inoculated with Cryptosporidium bailleyi oocysts. The mental status, body weight, number of Cryptosporidium oocysts excreatd daily, Index of bursa of fabricius (BF) and spleen of chickens and so on were observed. The results indicated that low does AHD could depress clinical symptom, incidence and mortality of chickens inoculated with C. bailleyi. For the low does AHD group, total amount of oocysts was lower and patent period was shorter compared with other groups, and the Index of BF and spleen respectively increased 36.73%(P<0.01) and 41.94%(P<0.01)compared with the infected control group and respectively 37.73%(P<0.O1)and 4.76%(P>0.05) compared with the high does group. The reserch shows that low does AHD has effect in preventing cryptosporidiosis and the alternative in does is needed for the effect is different with the does changing.