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This article was published in 1981
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Bluetongue Review
R.W. Burton, B.V.Sc., Veterinary Research Station, NSW Dept. of Agriculture, Glenfield
A number of viruses related to the blue tongue (BT) group have been described in Australia since the original bluetongue isolation of 1975. That virus, originally designated CSIRO 19 and subsequently shown to be BT type 20, has no relevance to the situation in N.S.W.
The following viruses, however, do have relevance to N.S.W.:-
| 1. | C.S.I.R.O. 154 | This virus has some relation to BT type 6, but is distinct from it. There is serological evidence for C.S.I.R.O. 154 being present in N.S.W., and it may have been active in 1980. However, the virus has not yet been isolated in N.S.W. |
| 2. | C.S.I.R.O. 156 | This virus is identical to BT type 1. The N.S.W. situation is the same as that described for C.S.I.R.O. 154 above. |
| 3. | C.S.I.R.O. 157 | This virus has only recently been isolated in Queensland, and appears to be a member of the Ibaraki group. Ibaraki virus first came to prominence in Japan, where it caused a BT - type illness, but in cattle, not sheep. Again there is serological evidence for this virus in N.S.W., but the virus itself has not been isolated. |
| 4. | Palyam group | Members of this group, probably D'Aguilar viruses, have been frequently isolated in N.S.W. There is some serological relationship between this group of viruses and the BT group. |
It must be stressed that at no time has any disease condition been linked to any of these viruses.
Monitoring in N.S.W.
Monitoring is based on a series of sentinel cattle herds located at Casino, Wollongbar, Grafton, Kempsey, Tea Gardens, Tocal, Glenfield and Kiama. In addition to virology and serology, insect collecting is carried out at each site, in conjunction with C.S.I.R.O., to understand the dynamics of potential vectors.
It has become apparent that there are many more orbiviruses (the genus to which bluetongue, Ibaraki, Palyam etc. belong) than originally suspected, and that their relationships are far more complicated, and less clear-cut, than serological grouping has suggested. The primary aims, therefore, are to attempt to isolate viral agents and understand the relationships between them, and then link those viruses to insect vector activity.
Unfortunately the present season seems to be a very poor one for virus activity, no doubt reflecting the drought conditions experienced throughout much of the state. The recent heavy falls of rain may alter this situation.