Diarrhoea outbreak caused by coinfections of Cryptosporidium parvum subtype IIdA20G1 and rotavirus in pre‐weaned dairy calves

Abstract

Diarrhoea is one of the most important syndromes in neonatal calves. In industrialized nations with intensive animal farming, Cryptosporidium spp. and rotavirus are primary causes of calf diarrhoea, but the role of these and other enteric pathogens is not clear in China. In November and December 2018, a diarrhoea outbreak was identified in over 150 pre‐weaned calves on a dairy farm in Heilongjiang Province, northeast China and approximately 60 calves died. To determine the cause of the outbreak, we analyzed 131 faecal samples collected from pre‐weaned calves (0–2 months) during (n = 114) and after the outbreak (n = 17). Initially, 10 diarrheic samples during the outbreak and 10 non‐diarrheic samples after the outbreak were screened for rotavirus, coronavirus, Escherichia coli K99 and Cryptosporidium parvum by using an enzymatic immunoassay (EIA). In addition, 81 other samples were tested specifically for rotavirus by EIA, and all 131 samples were analyzed for Cryptosporidium spp., Giardia duodenalis and Enterocytozoon bieneusi by PCR. The initial EIA analysis identified C. parvum (8/10) and rotavirus (5/10) as the dominant pathogens in calves during the outbreak, while both pathogens were detected at lower frequency after the outbreak (2/10 and 1/10, respectively). Further PCR analyses indicated that the occurrence of C. parvum infections in calves was significantly higher during the outbreak (75.4%, 86/114) than after the outbreak (11.8%, 2/17; odds ratio [OR] = 23.0), and was significantly associated with the occurrence of watery diarrhoea (OR = 15.7) and high oocyst shedding intensity. All C. parvum isolates were identified as subtype IIdA20G1. Among other pathogens analyzed, the overall prevalence of rotavirus, G. duodenalis and E. bieneusi was 19.8% (20/101), 38.9% (51/131) and 42.0% (55/131) in calves, respectively, without significant differences during and after the outbreak. Among the three pathogens, only the rotavirus infection was associated with diarrhoea in calves. More importantly, coinfections of C. parvum and rotavirus were significantly associated with the occurrence of watery diarrhoea in calves and were seen only during the outbreak. Thus, C. parvum subtype IIdA20G1 and rotavirus appeared to be responsible for this diarrhoea outbreak. Control measures should be implemented to effectively prevent the concurrent transmission of these enteric pathogens in pre‐weaned dairy calves in China.

High infectivity and unique genomic sequence characteristics of Cryptosporidium parvum in China

“…This does not appear to be the case with Chinese IId isolates in GKO mice. IId subtypes have been responsible for outbreaks of severe diarrhea in dairy calves in China with high mortality [ 14 , 17 , 29 , 30 ].…”

“…The IIdA19G1-GD, IIdA20G1-HB and IIdA20G1-HLJ isolates were collected from dairy calves in Guangdong (GD), Hebei (HB) and Heilongjiang (HLJ) provinces, China, respectively ( S1 Table ). Among them, IIdA20G1-HB and IIdA20G1-HLJ were obtained from dairy farms with outbreaks of cryptosporidiosis that experienced significant mortality [ 14 , 17 ]. Subtype identification was established using sequence analysis of the 60 kDa glycoprotein ( gp60 ) gene.…”

Detection of the dominant pathogens in diarrheal calves of Ningxia, China in 2021–2022

“…Wuzhong is the city with the most types of pathogens and the highest average detection rate, followed by Yinchuan. Because the etiology of calf diarrhea is more complex, in addition to other environmental factors, it is predominantly caused by pathogens [viruses ( 31 ), bacteria ( 1 ), parasites ( 32 )], especially Cryptosporidium , which is principally transmitted by fecal-oral transmission ( 33 ). Therefore, calf density is one of the important factors affecting its transmission rate, and Wuzhong, Yinchuan, and some counties in Shizuishan and Zhongwei are the location of cattle breeding areas in Ningxia, and the density of calf herds is extremely high more than other cities.…”

Development and Preliminary Evaluation of a Nanoparticle-Assisted PCR Assay for the Detection of Cryptosporidium parvum in Calves

“…Recently, the outbreaks of diarrhea caused by C. parvum have led to hundreds of deaths in calves on several farms in China, causing great economic losses to the farms [ 41 , 42 ]. With the application of the nano-PCR, we could rapidly identify C. parvum infection early, and the targeted interventions, such as isolating and treating infected animals, and sterilizing the environment, could be conducted to block the transmission of C. parvum among animals and minimize animal death and economic losses.…”