A recent meta-analysis of epilepsy attributable to neurocysticercosis indicated that more than 30% of epilepsy cases in sub-Saharan Africa may be due to the parasitic disease.
Arve Lee Willingham III, DVM, PhD, WHO/FAO Collaborating Center for Parasitic Zoonoses, Faculty of Life Sciences, University of Copenhagen, Denmark and Augustine Mugarura, MA, Vice Chair of the IBE Regional Executive Committee Africa and National Director of the Epilepsy Support Association, Uganda (ESAU) write about the growing concern regarding the spread of neurocysticercosis and a workshop held in Uganda address the problem.
Cysticercosis is emerging as a serious public health and agricultural problem in Eastern and Southern Africa (ESA). Caused by the pork tapeworm, Taenia solium, this zoonotic disease forms larval cysts in humans and pigs that can lead to epilepsy and death in humans, makes pork unsafe to eat, and reduces the value of pigs. It occurs where sanitation is poor, meat inspection is inadequate and pigs range freely, and so is strongly associated with poverty.
People become infected with the adult tapeworm form of the parasite (taeniosis) by eating infested raw or undercooked pork. Large numbers of the eggs of the tapeworm are shed in the infected persons stool and can be ingested by free-roaming pigs if people defecate outdoors. Pigs develop the immature larval form of the parasite (cysticercosis) with hundreds to thousands of small cysts, commonly called pork measles, forming in their muscles, heart and brain, rendering the pork unfit for consumption. Pigs thus affected usually show no signs of disease.
You can become infested with cysticercosis without eating pork.
People can also become infected with the cystic larval form of the parasite by ingesting T. solium eggs either from direct contact with a human tapeworm carrier or from contaminated food and water – thus one does not need to raise pigs or consume pork to become infected with cysticercosis! In humans the cysts often develop in the brain, causing a condition called neurocysticercosis, which can cause severe headaches, epileptic seizures and sometimes death.
Neurocysticercosis is considered to be the most common preventable cause of epilepsy in the developing world, rendering people incapacitated and unproductive, and sometimes leading to fatal accidents as a result of seizures. Although, theoretically, easy to control and declared eradicable, cysticercosis remains neglected in ESA, due to lack of information and awareness about the problems extent, lack of suitable diagnostic and management capacity, and a lack of appropriate control strategies.
The connection between tapeworms and epilepsy
The relationship between tapeworms and epilepsy came under the spotlight at a two day national workshop held 29-30 May in Kampala, Uganda. The workshop brought together animal and human health professionals from sixteen districts of Uganda which are considered likely to be endemic for Taenia solium cysticercosis.
The workshop, hosted by the Faculty of Veterinary Medicine, Makerere University, Kampala was called to launch a one year project Impact assessment and capacity building for prevention and control of Taenia solium cysticercosis in Uganda which is being funded by the Technical Cooperation Programme of the United Nations Food and Agriculture Organization (FAO).
The projects main objectives are:
- To assess the extent of T. solium cysticercosis in pigs and humans.
- To contribute to the design and implementation of a strategy for effective surveillance, prevention and control of T. solium infections.
The Ugandan Minister of Animal Industry opened the workshop noting that pork consumption has greatly increased in the country during the past few years and that the Government of Uganda is encouraging pig rearing as a way to boost rural incomes, especially among rural women.
He welcomed the project, as it will enhance the governments vision to combat rural poverty and benefit farmers, consumers and professionals. He appealed both to participants at the workshop and to those involved in the project to find ways and means through which pork consumers, those involved in pig rearing, and the animals being reared could be protected from infection with T. solium. The Minister encouraged the professionals to promote safe and hygienic pork production and consumption.
Migration aids the spread of neurocysticercosis
Evidence presented by researchers in both veterinary and medical fields painted an alarming picture of the level of T. solium infection in humans and pigs in the eastern and southern Africa region, underlining the fact that this disease is a serious public health risk not only to rural people in pig rearing communities but also in urban areas due to the migration of human tapeworm carriers and the transport of infected pigs and pork for consumption.
It was mentioned that in endemic communities pigs kept by many rural farmers are allowed to roam about to search of food and have access to human waste, which may contain T. solium eggs, as latrines/toilets may not be present or used and people may defecate in the bushes (being coprophagic, pigs like to eat human/animal solid waste). It was noted that, in Uganda, the government is vigorously promoting pig rearing but in many areas, both rural and urban, there are few or no established formal facilities for slaughtering pigs or inspecting pork; thus pork infected with T. solium may be available for consumption. People may be aware of cysts in the pork but may not be aware that it is dangerous to eat. A recent meta-analysis of epilepsy attributable to neurocysticercosis indicated that more than 30% of epilepsy cases in sub-Saharan Africa may be due to the parasitic disease. A recent study in northern Tanzania indicated about 15% of people with epilepsy involved in a small-scale survey were found to have neurocysticercosis, using CT scanning.
A Ugandan psychiatrist from the Medical Faculty of Gulu University, with a keen interest in epilepsy and public health issues, informed the meeting that he had documented cases of epilepsy in Uganda attributable to T. solium infection and he confirmed the direct relationship between epilepsy and T. solium neurocysticercosis.
The workshop participants were briefed about the ILAE/IBE/WHO Global Campaign against Epilepsy Out of the Shadows that aims to create awareness about epilepsy, and the epilepsy support programme in Uganda. Linkage to these epilepsy initiatives was considered essential, since it is anticipated that neurocysticercosis may be a major preventable cause of epilepsy in the country.
Staff from the Vector Control Division of the Ugandan Ministry of Health showed evidence from the onchocerciasis control programme that dermal lesions, initially attributed to onchocerciasis, another parasitic disease thought to cause epilepsy, were actually found to be subcutaneous cysts of T. solium.
The Ministry of Health is involved in conducting large-scale control programs for some other neglected tropical diseases including lymphatic filariasis, schistosomiasis, and soil-transmitted helminths (intestinal worms) and is actively participating in an integrated approach to surveillance and control of these diseases. It was discussed that a national initiative to map the endemic areas for these neglected tropical diseases should be extended to include T. solium infections, as it would be good to know areas of co-endemicity to understand the effects of treatment for these other diseases on human T. solium infections.
Some of the drugs being used can cure tapeworm infections; however they can also affect T. solium cysts though perhaps not killing them but affecting them enough that they may elicit seizures in previously nonsymptomatic neurocysticercosis cases.
Thus it will be important to know where cysticercosis is co-endemic with the other diseases, so that appropriate treatment and monitoring protocols can be introduced. Participants were led through a stakeholder analysis process and identified the relevant stakeholders, their roles and how to ensure their continued interest and participation in the cysticercosis surveillance and control initiative.
It was noted that for efforts to be effective and sustainable it is important to maintain open dialogue and communication and to deliver on all commitments made.
For more information please contact Dr Lee Willingham at the WHO/FAO Collaborating Center for Parasitic Zoonoses in Denmark at email@example.com
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