Dynamic Investigation Of Cryptosporidium Infection In Foals In Parts Of Xinjiang

Cryptosporidium is one of the common zoonotic Parasitic protozoa and is commonly prevalent worldwide.Foal was Infected by Cryptosporidium can show symptoms such as diarrhea,abdominal pain,loss of appetite,wasting and stunting,which can lead to death in severe cases.In this study,we investigated the dynamic infection of Cryptosporidium in foals in some areas of Xinjiang by microscopic observation and PCR method,aiming to understand and grasp the prevalence and species/genotype distribution characteristics of Cryptosporidium in foals in the region.(1)590 samples of manure from herding horses and foals were respectively collected consecutively in2018,2019 and 2020 in Altai,Tacheng and Ili regions in Xinjiang.and examined by Saturated Sucrose Solution Floatation Method The result showed that 314 samples were positive for intestinal parasites,with a total infection rate of 54.7%(314/590)and mixed infection rate of 18.3%(105/590);six species of intestinal parasites were found,with Strongylus as the predominant infective species,with an infection rate of 44.2%(254/590),Parascaris equorum,Coccidia,Tapeworm,Pinworm and Cryptosporidium,with infection rates of 24.2%(139/590),1.2%(7/590),6.8%(39/590),1.0%(6/590)and 0.5%(3/590),respectively.24.2%(139/590),1.2%(7/590),6.8%(39/590),1.0%(6/590)and 0.5%(3/590),respectively.The rates of Cryptosporidium infection in foals were 0.5%(1/191),0.5%(1/191)and 0.6%(1/192)in 2018,2019 and 2020,respectively,and 0,1.4%(2/143)and 0.7%(1/175)in foals in Altai,Tacheng and Ili regions,respectively.The results showed that intestinal parasitic infections were more common in some areas of Xinjiang,with Strongylus as the main infecting species and Cryptosporidium at a low rate.(2)To understand the distribution characteristics of Cryptosporidium species and genotypes in foals in some areas of Xinjiang,590 fecal samples of herding horses were tested for Cryptosporidium by PCR.It was found that the rate of Cryptosporidium infection in foals was 1.6%(9/590),which was higher than the detection rate by microscopic observation method(0.5%,3/590);the rates of Cryptosporidium infection in foals in 2018,2019 and 2020 were 0.5%(1/191),1.6%(3/191)and 2.6%(5/192),respectively,and there is no statistical difference in the infection rate of Cryptosporidium in different days of age.All nine PCR-positive samples were successfully sequenced and four Cryptosporidium species/genotypes were identified by sequence analysis,namely C.hominis(n = 3),C.parvum(n = 2),Cryptosporidium andersoni(n = 1)and C.horse genotype(n = 3).The result of the study suggest that there are genetically diverse distribution characteristics of Cryptosporidium in foals in some areas of Xinjiang.(3)To further understand the age dynamics of Cryptosporidium infection in foals,25 newborn foals from one Cryptosporidium-positive farm were selected for the study,and their fecal samples were collected at 30,60,90,120,150 and 180 days of age,for a total of 150 samples.Based on the Cryptosporidium SSU r DNA locus,fecal DNA was detected by PCR.17 out of 150 samples were positive for Cryptosporidium,with a total infection rate of 11.3%(17/150);the highest infection rate was found in 60-day-old foals at40.0%(10/25),while no Cryptosporidium infection was found in 120-day-old foals.All 17 PCR-positive samples were successfully sequenced,and C.horse genotype(n = 11)and microscopic C.parvum(n = 4)and C.meleagridis(n = 1)were identified by sequence analysis;there was no significant correlation between Cryptosporidium species/genotypes infecting foals at different days of age.The results suggest that 2-month-old foals are more susceptible to Cryptosporidium,and the monitoring and pathogenicity investigation of Cryptosporidium in newborn foals should be further strengthened.