Revealing the parasitic infection in diarrheic yaks by piloting high-throughput sequencing

Diarrhea a serious disease, reported to be related with changes in microbial diversity is widely epidemic in the yaks on the Qinghai Tibet plateau. Herein, we preformed high-throughput sequencing of the parasitic diversity in 3 groups of yaks i.e. healthy adult yaks (HA), diarrheic adult yaks (DA) and diarrheic yak calves (DC) in Gannan Tibetan Autonomous Prefecture. The results showed that 2 Phyla, 3 Classes, 5 Orders, 4 Families and 6 Genera were discovered in HA yaks; 2 Phyla, 3 Classes, 6 Orders, 6 Families and 8 Genera were found in DA yaks while 2 Phyla, 5 Classes, 5 Orders, 10 Families and 7 Genera were observed in DC yaks. At Phylum level, Nematoda and Apicomplexa were detected in all three yak groups; however, Apicomplexa was found to be conspicuously higher in the DC yaks as compared to DA yaks (p < 0.05). At Class level, Litostomatea, Chromadorea and Gregarinasina were found in all three yak groups, while Spirotrichea and Colpodea were only found in the DC yaks. At Order level, Vestibuliferida, Tritrichomonadida, Rhabditida and Eugregarinorida were observed in all three yak groups; and Neogregarinorida was noted HA and DC yaks while Trichomonadida and Hypotrichomonadida were only found in DA yaks. Tritrichomonadida was found to be relatively higher in the DA yaks when compared with HA yaks (p < 0.05) and DC yaks (p < 0.05). At Family level, Simplicimonadidae and Haemonchidae were found in all three yak groups. Trichostrongylidae was observed in both HA and DA yak groups. Syncystidae was established in both HA and DC yak groups except DA yaks. Trichomonadidae and Dictyocaulidae were only found in DA yaks. Plectidae, Strongylidae, Echinamoebidae, Lecudinidae, Pseudokeronopsidae and Panagrolaimidae were only discovered in DC yaks. Simplicimonadidae was found to be remarkably higher in DA yaks as compared to HA and DC yak groups (p < 0.05); and Haemonchidae was detected at higher levels in HA yaks as compared to DA and DC yaks (p < 0.05). At Genus level, Entamoeba, Buxtonella and Haemonchus were found in all three yak groups. Plectus and Echinamoeba were only found in DC yaks; while Trichostrongylus and Trepomonas were observed in HA and DA yak groups. The genus Gregarina was found in both diarrheic yak groups; while the genera of Tetratrichomonas and Dictyocaulus were observed in DA yaks only. The present study herein reported an insight of the change of parasitic diversity in diarrheic yaks at high altitude area, which shall make contribution towards the solid prevention of diarrhea in yaks.