3. Results
3.1. Occurrence of Enteric Pathogens inIll Calves during the
Outbreak
In the initial EIA analysis of major enteric pathogens in the 18
specimens from ill calves, 10 were positive for Cryptosporidiumspp., five for rotavirus, one for coronavirus, and none for
enteropathogenic E. coli . All five rotavirus-positive specimens
were also positive for Cryptosporidium spp. (Table 2). These 18
specimens were further analyzed for Cryptosporidium spp. using
the SSU rRNA-based PCR, leading to the identification of C.
parvum in 10 of them, including 9 of the 10 EIA-positive specimens. All
the C. parvum -positive specimens were successfully subtyped as
IIdA20G1 by sequence analysis of the gp60 gene.
3.2. Occurrence of Rotavirus inNeonatal (1-4-Week-Old)
Calves
During the outbreak, 8/37 (21.6%) specimens from neonatal calves were
positive for rotavirus. In contrast, 7/38 (18.4%) specimens from
neonatal calves were positive after the outbreak (Fig. 2). Altogether,
15 of the 75 fecal specimens from neonatal calves of 1 - 4 weeks were
positive for rotavirus by EIA. Among them, the infection rate was 21.1%
(8/38) in calves with watery diarrhea, 0% (0/6) in calves with moderate
diarrhea, and 22.6% (7/31) in calves without diarrhea
(χ2 =
1.66, df = 2, P = 0.437).