| Duck coccidia are protozoa of the phylum Apicomplexa, class Sporozoasida, order Eucoccidiorida, family Eimeriidae. Those belong to the genera Eimeria, Wenyonella, Tyzzeria and Isospora. Currently the coccidian species of ducks recorded in documents are about 23 species. Two speices of them parasitize kideys and others parasitize intestine. Duck coccidia are spreaded widely in the world, which have been reported in America, England, Holland, German, Hungary, Japan, Russia, China and so on. The domestic duck coccidia have been are recorded about 20 species in 14 provinces, cities and autonomous regions of China. The coccidian species of ducks have not been recorded until now in Shanghai. This paper studied the species and infection status of domestic duck coccidia in Shanghai, provided basis for preventing and treating duck coccidiosis.First, fresh faecal samples were gathered from 18 duck farms in the outskirts of Shanghai and duck coccidia were separated from these faeces. Free-coccidia-ducks were infected with sporulated oocysts of duck coccidian, then collecting faeces from 4 to 8 d after infection, isolating coccidia and sporulating. 405 sporulated oocysts were observed and measured by microscope with shooting system. 10 species of 3 genera of duck cococcidia were identified according to domestic and international documents. These species included 6 speies of Eimeria, 3 species of Wenyonella, 1 species of Isospora. They were Eimeria anatis, Eimeria danailovi, Eimeria saitamae, Eimeria battakhi, Eimeria schachdagica, Eimeria abramovi, Wenyonella anatis, Wenyonella philliplevinei, Wenyonella pellerdyi, Isospora mandarin. Tyzzeria perniciosa was not found, although it's the highest pathopoiesia.Secondly, the paper investigated prevalence of coccidia among domestic ducks in Shanghai. A total of 457 faecal samples were collected from 10 duck farms, 40~50 samples of each farm, and about 50 g of each sample. For qualitative check, 10 g was taken out from each faeces sample, adding water, filtering using gauze, centrifuging and floating by saturation salt solution. The oocysts of each sample were examined by using microscope. The positive samples were detected to infection level by quantitative method, counting the oocysts of per gram faeces (OPG). The results indicated that the infection rates of coccidia were 61% from 10 duck farms, 278 positive samples among 457 samples. The infection rate and OPG of samples were the higest from less than 3-month-old ducks, the infection rate was 100% and average OPG was 37 015 (from 1 200 to 112 200). The infection rate and OPG of samples were the lowest from 9~12-month-old ducks, the infection rate was 47% and average OPG was 1 167 (from 300 to 4 200).Thirdly, the paper observed the pathogenicity and the evacuation period of oocysts of duck coccidian by infection. For determining the earliest time of coccidian appearing in faeces, the faeces were checked from 72 h after infection. When oocysts were found in faeces, collected faeces of each group and counted OPG at intervals of 24 h until no oocysts in faeces. The results were that oocysts were found in faeces of all infection groups from 96 h to 264 h after infection. The evacuating period was 168 h. The evacuating oocyst peak occurred at 120~144 h after infection during the period. The symptom of ducks and the character of faeces were normal and the pathological changes of intestine were not obvious in all infection groups.Lastly, the paper isolated single oocyst from mixed species. One pure species was abtained from 30 ducks infected single oocyst. The oocysts were cultured to sporulating oocysts. The sporulating oocysts were observed by using microscope. The results were that the shape of oocysts was ovoid, the length and width of oocysts was 14.14~18.83μm×10.79~15.24μm (the average 16.9μm×13.0μm), the shape index of oocysts was 1.2~1.5 (the average 1.3). Finally, the speices was preliminary determined as Eimeria anatis.
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