Infections with rotavirus and coronavirus were studied in eight dairy farms and in three beef herds in Mozambique. Serum samples from 154 calves were tested for antibodies to rotavirus groups A and C and serum samples from 760 calves ,were tested forantibodies to bovine coronavirus enzyme-linked immunosorbent assays (ELISA). The total prevalence of serum antibodies to rotavirus in different farms ranged from 36 to 70%. For coronavirus between 81 to 100% of the animais were serologically positive. Inthe eight dairy farms 296 calves, up to three months of age, were clinically examined and faecal samples were collected and analyzed for the presence of rotavirus by a group A specific antigen ELISA and for rotavirus RNA by polyacryiamide gel electrophoresis (PAGE(. There was a significant (p<0.001) statistical association of diarrhoea and the presence of group A rotavirus antigen in faecal samples from calves younger than one month old. Rotavirus antigen was demonstrated- in 21 (20%) out of 107 calveswith diarrhoea and in9 (5%) out of 189 calves without diarrhoea. Rotavirus genomic RNA were demonstrated in 22 specimens and were among the 30 cases where group A rotavirus antigen had been detected by ELISA. The genome electropherotypes recognized wereall identified as of group A rotavirus. Rotavirus strains were also isolated in MA104 cells from the antigen positive faecal samples from 17 calves with diarrhoea and from 2 calves without diarrhoea.
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