BOVINE CORONAVIRUS DETECTION IN ADULT COWS IN BRAZIL

ABSTRACT

Winter dysentery is a bovine coronavirus (BCV)-caused disease that affects cows reported Europe, Japan, Canada and in the USA. The existence of enteric BCV infections in cows in an outbreak of diarrhea during the winter, a fact not reported in Brazil, has been surveyed in 9 stool samples with hemagglutination/ hemagglutination inhibition test and three were found positive. All 9 samples tested negative for rotavirus in PAGE. These results, the first description of BCV in adult cows in the Southern Hemisphere, show that winter dysentery also occurs in Southern, tropical areas and that BCV needs now to be considered in the aethiology of diarrheas in adult cattle in Brazil.

KEY WORDS:
Winter diarrhea; coronavirus; tropical; Brazil.

RESUMO

A disenteria de inverno é uma doença causada por coronavírus bovino (BCV) que afeta vacas adultas, já relatada na Europa, no Japão, no Canada e nos EUA. A existência de infecções entéricas de BCV em vacas, um fato ainda não relatado no Brasil, foi avaliada em 9 amostras fecais em um surto de diarréia durante o inverno, através da técnica de hemaglutinação/ inibição da hemaglutinação, quando 3 amostras foram positivas. Todas as 9 amostras foram negativas para rotavírus em PAGE. Estes resultados, a primeira descrição de BCV em vacas adultas no Hemisfério Sul, demonstram que a disenteria de inverno também ocorre em regiões tropicais e ao sul e que o BCV precisa ser considerado a partir de agora na etiologia das diarréias em bovinos adultos no Brasil.

PALAVRAS-CHAVE:
Diarréia de inverno; coronavírus; tropical; Brasil.

Winter dysentery caused by bovine coronavirus in adult cows is a disease first described by HORNER et al. (1975) and reported in Europe, Japan, Canada and in the USA (JACTEL et al.; 1990; ALENIUS et al., 1991; FUKUTOMI et al., 1999; MILLANE et al., 1995; CHO-KYOUNG et al., 2000). This survey aimed to evaluate the existence of enteric BCV infections in cows in an outbreak of diarrhea, a fact not reported in Brazil. Nine fecal samples where collected from adult cows with symptomatic diarrhea in a outbreak in a dairy farm from São Paulo State, Southeastern Brazil, during the winter month of June. Fecal suspensions were prepared in PBS 0,01M / BSA 0,1% pH 7,2 to a 1:4 final dilution, centrifugated under 12,000xg/30’ and the supernatant was used to bovine coronavirus detection. Fecal suspensions were diluted 2-fold in PBS 0,01M / BSA 0,1% pH 7,2 in 96 wells U-plates to a 25 µL final volume/dilution, adding 25 µL of a 0,4% hamster red cells suspension in PBS 0,01M / BSA 0,1% pH 7,2 to each well. BCV Kakegawa strain growth in HmLu-1 cells was used as positive control and PBS 0,01M / BSA 0,1% pH 7,2 as negative control. After 2 hours at room temperature, end point titers were read as the inverse of the last dilution in which hemagglutination (HA) could be found. Those samples with HA titers >4 where tested in hemagglutination inhibition test (HI) in 96 wells V-plates, diluting fecal suspensions 2fold in PBS 0,01M / BSA 0,1% pH 7,2 to a 25 µL final volume/dilution; in the next step, 25 µL of a caolimtreated hiperimmune anti-BCV ovine serum withd 8 hemagglutination inhibition units were added. After a 1-hour incubation at 37 ºC, 25 µL, of a 0,4% hamster red cell suspension in PBS 0,01M / BSA 0,1% pH 7,2 to each well and the plates where incubated for 2 hours at room temperature, end point titers were read as the inverse of the last last dilution in which hemagglutination could be found. Samples where considered positive if a at least 4fold fall in titer was found (SATO et al.,1977).

Three out nine samples were positive to bovine coronavirus in HA/HI test. All samples tested negative for rotavirus in PAGE (HERRING et al., 1982).

The finding of bovine coronavirus in stool of cows with clinical symptoms of diarrhea during a winter month shows that BCV-led winter diarrhea, formerly thought as restricted to the Northern hemisphere, occurs also in Southern, tropical areas and bovine coronavirus needs now to be considered in the aethiology of diarrheas in adult cattle in Brazil.

REFERENCES

• ALENIUS, S.; NISKANEN, R.; JUNTTI, N.; LARSSON, B. Bovine coronavirus as the causative agent of winter dysentery: serological evidence. Acta Vet. Scand, v.32, n.2, p.163170, 1991.
• CHO-KYOUNG, O.H.; HALBUR, P.G.; BRUNA, J.D.; SORDEN, S.D.; YOON, K.; JANKE, B.H.; CHANG, K.; SAIF, L.J.; CHO, K.O.; YOON, K.J.; CHANG, K.O. Detection and isolation of coronavirus from feces of three herds of feedlot cattle during outbreaks of winter dysentery-like disease. J. Am. Vet. Med. Assoc., v.217, n.8, p.1191-1194, 2000.
• FUKUTOMI, T.; TSUNEMITSU, H.; AKASHI, H. Detection of bovine coronavirus from adult cows with epizootic diarrhea and their antigenic and biological diversities. Arch. Virol., v.144, n.5, p.997-1006, 1999.
• HERRING, A.J.; INGLIS, N.F.; OJEH, C.K.; SNODGRASS, D.R.; MENZIES, J.D. Rapid diagnosis of rotavirus infection by direct detection of viral nucleic acid in silver-stained poliacrylamide gels. J. Clin. Microbiol., v.16, n.3, p.473477, 1982.
• HORNER, G.W.; HUNTER, R.; KIRKBRIDE, C.A. A coronaviruslike particle present in faeces of cows with diarrhea. New Zealand Vet. J., v.23, n.5, p.98, 1975.
• JACTEL, B.; ESPINASSE, J.; VISO, M.; VALIERGUE, H. An epidemiological study of winter dysentery in fifteen herds in France. Vet. Res. Commun., v.14, n.5, p.367379, 1990.
• MILLANE, G.; MICHAUD, L.; DEA, S. Biological and molecular differentiation between coronaviruses associated with neonatal calf diarrhea and winter dysentery in adult cattle. Adv. Exper. Med. Biol., v. 380, p.29-33, 1995.
• SATO, K.; INABA, Y.; KUROGI, H; TAKAHASHI, E.; SATADO, K.; OMORI, T.; MATUMOTO, M. Hemagglutination by calf diarrhea coronavirus. Vet. Microbiol., v.2, p.83-87, 1977.

Publication Dates

• Publication in this collection
  16 Sept 2024
• Date of issue
  Apr-Jun 2002

History

• Received
  26 Dec 2001
• Accepted
  04 Mar 2002