There are typically no signs of bovine cysticercosis infection in live cattle.

Post-mortem inspection may identify cysts in the muscle. The muscles most commonly affected are the heart, tongue, diaphragm and muscles of the jaw. Viable cysts are oval, fluid-filled, about 0.5–1 × 0.5 cm, translucent and contain a single white scolex. They are contained in a thin, host-produced fibrous capsule. Cysts are also occasionally found in the liver, lung, kidney, fat and elsewhere.

If you suspect bovine cysticercosis you should collect samples of the lesion for laboratory diagnosis and notify either Local Land Services (1300 795 299) or the Department of Primary Industries and Regional Development (animal.biosecurity@dpird.nsw.gov.au) within one working day.

Bovine cysticercosis is typically diagnosed following meat inspection at abattoirs. Inspection can include palpation and visualisation of tissues for detection of cysts.

If Cysticercus bovis lesions are suspected, both fresh (chilled and/or in 80% ethanol) and fixed (in neutral buffered formalin at a 10:1 ratio of formalin) samples should be collected and submitted to the NSW Animal and Plant Health Laboratories (Elizabeth Macarthur Agricultural Institute) for histopathological examination and PCR to confirm or exclude infection.

Further information and laboratory submission forms

Figure 1 – Life cycle of Cysticercus bovis

Humans and cattle are the only hosts in the Cysticercus bovis lifecycle: the human must get the tapeworm from cattle (meat) and cattle only get the infection from humans (faeces).

The tapeworm occurs in the small intestine of humans, and although it is generally 4-8 metres long, it can reach 15 metres. Like all tapeworms, its scolex (head) attaches to the bowel wall and it has up to 2000 body segments. Each segment contains up to 80 000 eggs. The end segments of the tapeworm detach and are passed with faeces where they look like white fleshy capsules similar to a grain of rice.

If the eggs in the tapeworm segments find their way onto pasture or other feedstuffs, cattle may ingest the eggs which then hatch in the small intestine, develop into embryos and penetrate the bowel wall. They are carried through the bloodstream to various muscles where they develop into the Cysticercus bovis cysts.

The cysts may remain infective for up to 2 years and are most often found during meat inspection at abattoirs. About 10-20% of cysts found at abattoirs are still alive, the remainder have degenerated and, whilst still visible, are no longer infective to people. If people eat live cysts in rare beef or other bovine meat products, the cysts develop into a tapeworm in their small intestine and the cycle continues.

Humans can only become infected with the tapeworm causing bovine cysticercosis by eating meat containing the cysts. If people eat live cysts in rare beef or other bovine meat products, the cysts develop into a tapeworm in their small intestine.

Sometimes the tapeworm affects human health, but often it goes undetected. In rare cases the cystic intermediate stage can lodge in the brain of people and cause serious disease.

Factors that increase the risk of people being infected with the tapeworm include the consumption of rare beef, particularly in some overseas countries where the tapeworm is more common. People can minimise their chance of infection through the following actions:

• Cook beef to a temperature of at least 57^oC (that is until the meat is cooked uniformly through to the centre) to kill the cysts
• Freeze beef for 10 days at -8 to -10^oC to kill the cysts

Anyone who suspects they might have a zoonotic disease should contact their doctor or NSW Public Health (1300 066 055)

Prevention and management

Bovine cysticercosis can be prevented by ensuring that there is no contamination of pasture or other cattle feeds with huma feacal material. This can include:

• Practising good on-farm hygiene
• Avoid grazing around domestic sewage systems
• Ensuring that reclaimed sewage water used for irrigation is adequately treated
• Preventing spills of untreated wastewater
• Ensuring feed products come from a reputable manufacturer

When bovine cysticercosis is detected at an abattoir, an investigation by the Department of Primary Industries and Regional Development in conjunction with Local Land Services will follow in accordance with the Departmental procedure (available in other resources). This will include an investigation of the property of origin of the cattle to try to determine the source of the Cysticercus bovis contamination. Depending on the findings of the property investigation, a range of management options may be used to minimise the ongoing risks posed by the contamination.

Resources

• Procedure – Bovine Cysticercosis PDF, 467.53 KB
• Laboratory website – Cysticercus bovis
• WOAH Terrestrial Manual 2021 – Chapter 3.10.3. – Cysticercosis
• Integrity Systems – Risk Management of Cysticercus bovis in LPA and NLIS