By Roelof Bezuidenhout

Many parts of the Eastern Cape have a high prevalence of the parasitic infection known as neurocysticercosis (NCC), a leading cause of serious neurological conditions such as seizures in rural populations worldwide. Effective treatments are available internationally, but these products have been rejected by South African regulatory authorities.

NCC is caused by larval cysts of Taenia solium, a tapeworm that cycles between humans and pigs. It is recognised as one of the most neglected zoonotic infections globally, particularly affecting resource-poor communities where people live in close proximity to livestock and sanitation infrastructure is lacking.

According to Dr Caryn Shacklock, laboratory manager at Afrivet, NCC is most common in areas where pigs roam freely and come into contact with human waste. “If a person accidentally ingests tapeworm eggs shed in human faeces, the larvae can migrate to the brain and form cysts, potentially leading to epilepsy,” she explains. Of the estimated 50 million people living with epilepsy globally, 80% are in regions where T. solium is endemic – and in up to 30% of those cases, this parasitic worm is the root cause.

The tapeworm’s life cycle is complex, and the link between consuming undercooked pork and the eventual onset of symptoms is not well understood by the general public. In fact, it may take five to ten years for neurological symptoms to appear after infection, making it difficult to trace and assess NCC’s prevalence accurately within a community.

Research over the years has highlighted the burden of NCC in the Eastern Cape. One study found that more than 60% of epilepsy cases diagnosed in the province were linked to NCC. The region poses a particular challenge: Many rural households keep pigs that live closely alongside humans, and pit latrines – often accessible to animals – remain common.

Prevention is possible

The adult tapeworm resides in the human small intestine, shedding eggs via faeces. When pigs ingest these eggs, larvae migrate into the muscles and form cysts, known as cysticerci. Fortunately, a breakthrough vaccine has been developed to protect pigs from the infection, effectively breaking the transmission cycle.

“When used in conjunction with a specific dewormer that will kill the larvae that are encysted in the pig’s muscles, it is possible to eliminate NCC from a community in a short period of time,” Dr Shacklock says. “This solution is monumental, but not available here.”

A team at the University of Melbourne in Australia developed the vaccine, and it is currently produced and sold by an Indian animal vaccine company. Afrivet imported the vaccine under a special permit in 2021 for a pilot project in the Eastern Cape, and applied to have the vaccine and deworming product formally registered for local use. Unfortunately, the products did not pass the regulatory requirements, and the applications were denied. Short of repeating very expensive and rigorous trials here in South Africa, there is no way to appeal this decision, Dr Shacklock says.

“We have offered our support to state veterinary services in the Eastern Cape should they wish to bring the vaccine in on a permit for a specific intervention, but as far as I know, the vaccine is not currently being used in local communities.”

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