From June, 1964, to May, 1965, ten outbreaks of Anthrax were diagnosed, with laboratory confirmation, in the Condobolin Pastures Protection District. One of these presented some unusual features and is reported here.
On March 5, 1965, the death of two sows was investigated. The owner stated that neither sow was apparently ill on the previous day. One of these sows died overnight without a struggle. The other sow was seen to be sick in the morning and the owner hunted her about 20 yards to a sty, before reaching which she had violent convulsions and died. A third Sow was seen to be sick but the only signs were depression and a tucked up appearance. This sow responded to penicillin treatment. (The property had no previous history of Anthrax as far as could be ascertained from office records and owner's experience.)
Autopsies were done on both these sows. The signs in the second to die, dead five hours, were:
1. Blood-tinged fluid in the peritoneal cavity.
2. Gross thickening of the mesentery, which had a gelatinous appearance. The lymph nodes were large and juicy.
3. The wall of the small intestine at the level of the thickened mesentery was ruptured, there being one large hole about one inch across and several smaller perforations.
4. The spleen was enlarged but not pulpy.
The other sow, which had been dead up to 24 hours, showed similar post-mortem signs. The fluid in the peritoneal cavity was bloodstained. There was no perforation of the intestine. The diagnosis of Anthrax was confirmed at V.R.S. Glenfield, and the entire herd was vaccinated on March 6, 1965.
On March 10, one sow died with typical swelling of the throat, and there was a bloody discharge at the anus. On the same day another sow was seen sick and was grossly swollen in the pharyngeal region. This sow responded to penicillin treatment.
On April 1, another sow, on the same property, which had been vaccinated on March 6, was autopsied. This sow had been dead a considerable time and putrefaction was advanced. The carcass was bruised markedly along one side, indicating, possibly, violent struggling.
The post-mortem picture differed only in degree from that described for earlier deaths. The rupture of the intestine was of longer standing, as indicated by a more marked peritonitis, but adhesions had not developed. Intestinal contents, including wheat grains, were present in the peritoneal cavity. The thickening of the mesentery was less gelatinous.
No Anthrax bacilli were seen when smears were examined at Veterinary Research Station Glenfield. At no time did any young pigs die, and no pigs have died since April 1, 1965.