One of the many consequences of the flood events seen in recent years was the overflow of sewage on to farming land, which occurred in isolated instances.
The primary reason this is a concern is due to the threat of meat contamination with beef measles.
Beef measles is a stage in the lifecycle of a tapeworm of humans. They are seen as small cysts found in muscles of cattle at slaughter.
In other words, people are the cause of infection in cattle even though humans with tapeworm infections show no ill effects. Humans become infected by eating raw or undercooked meat containing a cyst.
Cattle become infected by grazing pasture contaminated with human faeces that contain tapeworm eggs, therefore the concern during flood events.
Once the tapeworm eggs are eaten by cattle the immature tapeworm is released and burrows through the intestinal wall, reaches the blood stream and migrates to a muscle in the animal.
They are mainly found in the muscles of the jaw, tongue, heart, and diaphragm of cattle, and are less commonly found in other muscles of the animal.
Infection with beef measles has no observable effect on the health of cattle. Routine meat inspection in abattoirs enables beef measles cases to be detected. Detection may lead to condemnation of part of the carcass.
Beef measles is a notifiable disease. Once detected, the cattle’s National Livestock Identification System (NLIS) details are used to trace the property of origin. The owner is then contacted by Agriculture Victoria staff and advised on the nature and control of beef measles.
Beef measles infections commonly originate from paddocks that have been contaminated with septic tank drainage, and from properties that have campsites or properties frequented by people where human faeces have not been properly disposed of.
In the case of the flood event, cattle exposed to the overflow of sewage were assigned a status through the NLIS system.
The control of beef measles relies on reducing the exposure of cattle to tapeworm eggs and preventing the human ingestion of infective cysts.
Medication is very effective in eliminating tapeworms from humans.
For further information, contact your local veterinarian or Agriculture Victoria veterinary or animal health officer, or in NSW your Local Land Services.
Dr Jeff Cave is senior veterinary officer with Agriculture Victoria.