K.D. Murrell^[1] and Z. Pawlowski^[2]

INTRODUCTION

The terms cysticercosis and taeniasis refer to food-borne zoonotic infections with larval and adult tapeworms, respectively. The important features of these zoonoses are that the larvae are meatborne (generally beef or pork) and the adult stage develops only in the intestine of the human host (obligate). Taenia saginata (the beef tapeworm), T. saginata asiatica (Taiwan Taenia) and T. solium (the pork tapeworm) are the most important causes of taeniasis in humans. Cysticercosis is a tissue infection with the larval cysticercus or metacestode stage, and occurs most commonly in pigs and cattle; Taenia saginata occurs only in beef, T. saginata asiatica in pig organs, and T. solium primarily in pork. Humans acquire the adult stage through eating improperly cooked infected meat.

Taenia solium is unique because the larval or cysticercus stage can also infect humans and cause cysticercosis/neurocysticercosis (man acts as an intermediate host in this case) (Pawlowski & Murrell, 2000). Infection with the cysticercus stage is responsible for almost all serious human disease caused by these taeniid tapeworms (Nash, 2003). These cestodes are cosmopolitan in distribution, and are highly endemic in Latin America, Africa and Asia where poverty conditions such as poor sanitation, and intimate contact between humans and their livestock are commonplace (Murrell, 2005; Pawlowski, Allan & Meinardi, 2005). It has been estimated that millions of people worldwide are infected with T. solium. For example, more attention to this zoonosis is occurring in sub-Saharan Africa because of the growing recognition of the importance of neurocysticercosis (larval infection of the central nervous system) in epilepsy, a disease that is now the subject of a global public health campaign, Out of the Shadows (Diop et al., 2003).

Although the life cycle cannot be maintained in regions that have adequate sanitation and good animal husbandry practices, these regions are still vulnerable, owing to immigration of people from highly endemic regions carrying infections of the adult stage (taeniasis). Such introduced infections account for an increased global distribution to non-endemic regions such as in the United States and Europe. These human carriers can contaminate the environment of others, leading to secondary infections (Murrell, 2005; Pawlowski, Allan & Meinardi, 2005).

In addition to the importance of this relatively neglected food-borne zoonosis as a cause of morbidity and mortality in many non-developed regions, it is also being recognized as a cause of loss of income for farmers with marginal subsistence. The rapid expansion of smallholder pig production in Africa has led to a significant increase in cysticercosis in pigs and humans, an important problem for governments seeking to increase livestock production and rural incomes. These events are not unique to Africa, however, and are the impetus for international concern and actions, such as the recent recognition of the importance of neurocysticercosis by the 56^th World Health Assembly (WHO, 2002), which issued a report on control of neurocysticercosis. This report highlights important issues and actions that need to be taken to control neurocysticercosis:

• Recognition that cysticercosis of the central nervous system is the most important neurological disease of parasitic origin in humans. It causes serious morbidity in areas where T. solium is endemic, and is known to be a leading cause of epilepsy, which has profound social, physical and psychological consequences.

• Because neurocysticercosis is an important cause of epilepsy, it places particular demands on health services; the burden of disease will dramatically increase as result of social stigmatization and discrimination.

• Human cysticercosis is a disease associated with poverty in areas where people eat pork and traditional pig husbandry is practiced. The spread of this disease is facilitated by poor hygiene, inadequate sanitation and the use of untreated or partially treated wastewater in agriculture. However, cysticercosis can also occur in individuals who do not raise pigs or consume pork.

The report points out that more than a decade ago (1993) the International Task Force for Disease Eradication (ITFDE) declared T. solium "a potentially eradicable parasite" (Schantz & Tsang, 2003). More recently, ITFDE called for a large demonstration project on effective control to be carried out; such a "proof of concept" would probably be the greatest single stimulus to further action against this potentially eradicable disease. However, there is as yet no truly successful intervention programmes instituted anywhere at a national level to achieve this goal. Until then, both the WHO and ITFDE urge medical and veterinary sectors to cooperate in establishing national prevalence, economic impact studies, and to establish surveillance reporting programmes. These efforts should adopt up-to-date diagnostic tools and clinical management procedures, employ anthelmintic for the treatment of humans and pigs, ensure high standards of meat hygiene and greater veterinary control over pig husbandry and slaughter practices, and give wider health education on the risks and prevention of cysticercosis. Constraints on resources and expertise needed to implement control programmes are significant to severe in most endemic countries; these countries are resource-poor.

CURRENT SITUATION

Prevalence and distribution

Global distribution of Taenia solium taeniasis/cysticercosis

Taenia solium is an important zoonosis in many pork-eating countries and is usually associated with low social and economic development. The prevalence of T. solium infection varies greatly according to the regional level of sanitation, pig husbandry practices and eating habits. It is very difficult to evaluate the prevalence of T. solium taeniasis because the coproscopical methods used for survey are not completely adequate and usually cannot differentiate between T. solium and T. saginata infections (Dorny et al., 2003). Therefore data on prevalence of adult worm infections are generally considered very conservative. Similarly, prevalence data based on serological methods may overestimate infection rates because presence of antibody may be the result of exposure to eggs and early but unsuccessful infection (Dorny et al., 2003).

Africa

Taenia solium is an emerging and expanding zoonosis in Africa (Zoli et al., 2003). Data from West and Central Africa suggest that investigations of human cysticercosis based on the prevalence observed in the pig population often underestimate true transmission rates but that there are regions of hyperendemicity (hyperendemic prevalence indicates a constant occurrence of the disease at a high transmission level). The high prevalence of pig cysticercosis should be expected to be accompanied by obvious and frequent T. solium tapeworm infections in man. A similar pattern is seen in eastern and southern Africa, where the prevalence in pigs is reported to range from 20 to 40 percent (Mafojane et al., 2003). Because of the growing interest among veterinarians and agriculturists in porcine cysticercosis, the information on pig infection is in many instances more extensive than that for human infections.

The incidence data in humans are very limited owing to a lack of adequate surveillance, monitoring and reporting systems, although the recognition of its status as a serious and emerging threat to public health is increasing. Concern is growing in eastern and southern Africa that the rapid expansion of pig farming and pork consumption will exacerbate the problems with T. solium cysticercosis; since 1961 the pig population in the countries of Uganda, Tanzania, Kenya, Zambia, Zimbabwe, and Mozambique has increased nearly threefold (in Uganda over sixfold) (Phiri et al., 2003).

Latin America

Due to the very active research efforts in this region a large amount of data has accumulated that clearly demonstrate that there is a very substantial risk of infection with T. solium for residents of many Latin American countries, although the prevalence rates vary from country to country (Flisser et al., 2003). Concerning cysticercosis in the human population, the frequent finding of neurocysticercosis in autopsy cases from general hospitals, its notable presence (4 to 6 percent) among the patients of specialized neurological institutions and the overall serological reactivity to cysticercus antigens found in the general population (e.g. the United Mexican States) indicate an active transmission of cysticercosis in the region.

Porcine cysticercosis is also frequently found at meat inspection in the abattoirs of Latin America but again these data are thought to be conservative indicators since ostensibly infected pigs (often identified by simple lingual palpation) are usually not taken to the slaughterhouse, but slaughtered elsewhere (clandestine marketing) (Gonzales et al., 2003). In the Republic of Peru, where infection rates in pigs vary from 14 to 25 percent, virtually no recognized infected pigs are processed at local slaughterhouses.

Europe

Neurocysticercosis is infrequently encountered in most of Europe. However, owing to increased immigration and travel, T. solium cysticercosis is likely to be diagnosed with increasing frequency and there is evidence that in some regions in Europe T. solium infection can be acquired locally; a recent survey revealed that out of a total of 45 cases of neurocysticercosis diagnosed between 1996 and 2000, 11 were autochthonous cases (Overbosch et al., 2002).

Asia

In Asia this zoonosis has been known to occur for several hundred years, but until recently, it has not received much attention; consequently, epidemiological information for the region is not extensive (Rajshekhar et al., 2003).

T. solium taeniasis and cysticercosis is common in the Republic of Indonesia (Simanjuntak & Widarso, 2004). Very high prevalences in the Wissel lakes area in western Irian Jaya have been associated with an "epidemic" of epilepsy and burns. The prevalence of T. solium infections is also high in Bali. Serosurveys in Irian Jaya using immmunoblots revealed an eight to ten percent prevalence rate; approximately two percent of 548 examined persons had demonstrable taeniasis, half of which were diagnosed as T. solium, studies in Irian Jaya indicate that the majority of people with epilepsy harboured T. solium cysticercosis.

Cysticercosis is prevalent in nearly all of the Republic of India, particularly in the north (Rajshekhar, 2004). Significantly, neurocysticercosis accounts for 8.7 to 50 percent of patients with recent onset of seizures. The peculiarity of the disease in the Republic of India is the high incidence of patients with the solitary form of the disease, the solitary cysticercosis granuloma; 60 to 70 percent of Indian patients with neurocysticercosis have a solitary cysticercosis granuloma. The prevalence of taeniasis is reported to be between 0.5 to 2 percent, although surveys in Uttar Pradesh found 38.7 percent of people in a pig rearing community had taeniasis.

T. solium infections have also been reported from the Kingdom of Thailand, the Republic of Korea and are sporadically reported in the Taiwan Province of China. A recent assessment of the cysticercosis situation in the People's Republic of China revealed that human cases of taeniasis and cysticercosis were found in 29 provinces, municipalities and autonomous regions, with five particularly endemic zones (Chen & Zhou, 2004). The average incidence of T. solium taeniasis in the regions surveyed range from 0.05 to 15 percent, while the number of people with cysticercosis was estimated at 3 to 7 million. In the endemic areas, pig cysticercosis varied from 0.4 to 15 percent, and occasionally up to 40 percent.

USA: The impact of immigration and travel

As in Europe, most cases of T. solium taeniasis/cysticercosis in the USA are attributed to immigration and travel. However, it has been reported recently that among the rising number of cases being seen in the country's western states, a proportion appears to be locally acquired. A retrospective analysis of hospital records (1995-2000) in Oregon revealed 89 hospitalizations due to cysticercosis, five of which occurred in people who had not travelled or lived outside the United States (Engels, 2003). In California, over a 12-year period (1989-2000) a total of 124 cysticercosis deaths were identified, representing a death rate of 3.9 per million population; the large majority were foreign born, predominantly in the United Mexican States (Dorny, Brandt, & Geerts, 2005). However, nearly 14 percent of deaths were among people born in the United States, some of whom may have had autochthonous infections, although travel-related exposure cannot be ruled out as a source of infection.

Important risk factors in the epidemiology of T. solium cysticercosis

(Murrell, 2005; Pawlowski, Allan & Meinardi, 2005; Kyvsgaard & Murrell, 2005)

The major risk factors related to transmission of T. solium eggs to pigs can be summarized as follows:

• Extensive or free-range pig rearing in households lacking latrines, and outdoor human defecation near or in pig-rearing areas.

• Allowing pigs to scavenge and eat human faeces (sanitary policeman).

• Deliberate use of human faeces as pig feed.

• Connecting pigpens to human latrines (pigsty privies).

• Use of sewage effluent, sludge or "night soil" to irrigate and/or fertilize pig pastures and food crops.

• Human carriers involved in pig rearing and care.

The risk factors important to the transmission of cysticerci to humans are:

• Lack of comprehensive and satisfactory meat inspection at pig slaughter.

• Clandestine marketing of pigs to avoid inspection.

• Cultural preferences for eating raw or improperly cooked pork. Studies have shown that the problems of illegal slaughter and marketing are widespread and their solution will require substantial efforts in veterinary control. The habit of eating raw or improperly cooked pork is also a very intractable trait, but hopefully, this can change through education.

THE MOST IMPORTANT RISK FACTORS INVOLVED IN HUMAN-TO-HUMAN TRANSMISSION ARE:

Low economic status, low level of household sanitation and low personal hygiene standards.

History of passing proglottids by a member of a household or a member of the community in frequent contact with household. Household or community food handlers and childcare givers (carriers) are potentially very high risk factors.

Frequent pork consumption.

THE WAY FORWARD: SPECIFIC CAPACITIES NEEDED TO IMPLEMENT CONTROL ACTIVITIES.

There is a consensus that from the standpoint of disease transmission to humans and maintenance of the parasite's life cycle, the adult tapeworm is of primary importance (Pawlowski, Allan & Meinardi, 2005; Pawlowski, 2002). The expertise needed to implement a control programme (detailed below) is diverse and must be provided through multidisciplinary cooperation between the medical, veterinary and public health sectors (and, perhaps, the education sector).

Strategy for T. solium infection control

1. Prevention of taeniasis in humans

The prevention of environmental contamination with Taenia eggs is of paramount importance in both prevention and control schemes. The development of improved sanitation and hygiene practices have had a major impact on the occurrence of cysticercosis in developed countries, and also among urban dwellers in the developing countries, because of their effect on the transmission of Taenia eggs (Pawlowski, Allan & Meinardi, 2005; WHO, 1983). The installation of adequate sanitation and the adoption of safe animal husbandry practices, however, are very problematical in these resource-poor areas, and therefore, prevention strategies must rely on multiple approaches, tailoring each to the special features of the particular endemic area (Kyvsgaard & Murrell, 2005).

In general, these strategies are:

• meat inspection to prevent human infection;

• improved farm management to ensure that pigs and cattle are protected from ingesting feed or water contaminated with human faeces to prevent cysticercosis in animals;

• screening of farm workers for taeniasis, and treatment if warranted;

• proper treatment of sewage effluent and sludge to kill Taenia eggs, and regulation of the use of effluent and sludge for agricultural purposes;

• control of pig and cattle marketing systems, including the provision of incentives to ensure owner compliance; and

• health education of both farmer and consumer.

2. Prevention of cycticercus infections in people

Focus of Control Effort

A control programme can be based on the maximal use of existing medical and veterinary services to control specific foci of T. solium infection (Pawlowski, Allan & Meinardi, 2005), therefore capacity building should emphasize:

• education and training of the medical and veterinary staff;

• ensuring their mutual cooperation; and

• establishment of a national/regional management structure.

Specifically, standardized protocols on how to define the potential foci of T. solium infection (a case, a family, a locality) and on how to treat human tapeworm carriers in a foci have to be developed and communicated to all the levels of medical services, especially those in endemic areas that deal with peripheral health units assigned primary health care. Importantly, the terms of local cooperation between local medical and veterinary services in defining T. solium foci, and the exchange of available information, must be developed and promoted. Of critical importance, a system of supervision to ensure that the programme is implemented and managed correctly has to be established, and any identified obstacles removed.

Logistics and management of control programmes

Establish a committee or a single person to be responsible for the implementation of preventive and control measures at various organizational levels (regional, national, district or community). The international agencies should also designate an officer responsible for coordination of various control approaches and activities.

Create a reporting system - as simple as possible - at all levels of existing medical (taeniasis, cysticercosis) and veterinary (cysticercosis) services. Produce and distribute a protocol for active surveillance activities in endemic areas, commensurate with the local human and technical resources. Ensure regular analysis of the incoming data and use the analysis for further decision-making at the national and/or local levels.

Institute a training programme for medical, public health and veterinary services personnel who will be involved in carrying out the control programme. They must be trained in the implementation of the preventive and control measures relevant to the local human and financial resources, as well as to the local cultural, environmental and economic conditions. This can be accomplished through government-supported training at academic institutions, or in special courses conducted by government agencies (e.g. public health or veterinary public health).

Create at the national or local levels groups of people involved in development and implementation of the prevention and control programmes in the highly endemic areas. Support those groups with the necessary scientific, logistic and financial assistance required to carryout the plan.

Revise existing legislation, which may be related to prevention or control of taeniasis/cysticercosis, i.e. animal production and meat distribution as well as sanitation, and diagnosis and treatment of human tapeworm carriers.

Promote and justify the control programme at the district, national and international levels using valid estimates of the health and economic burden of human taeniasis/cysticercosis.

Major control elements dependent upon capacity building

Improvements in meat inspection
(Kyvsgaard, & Murrell, 2005)

Various studies have shown that improvement of the effectiveness of inspection staff depends upon such factors as training, rewards, motivation, psychological disposition, adequate lighting and improving methods of processing carcasses These are important, but they do not overcome the problem that there is no specific site for examination that can be relied upon to detect all infected carcasses.

Failures in the detection of cysticercosis during post-mortem inspection may be reduced if meat inspection is practiced by experienced and conscientious inspectors under optimal conditions; these should include adequate rest periods. These conditions also include good lighting, a low noise level and a system of inspection integrated with slaughtering procedures. Meat inspection manuals should be explicit in their directions for the examination of carcasses and organs for cysticerci. Meat inspection should be well planned, organized and managed at every slaughterhouse. It has been observed that the efficiency of meat inspection diminishes after two hours of routine work in a given position.

Health education and training of professionals - "training of trainers"

Education is crucial to any control effort, and must be given at all levels of a programme. All health education effort has to be planned and conducted through a net of professionals who are working in the field or who have contacts with the public (Pawlowski, Allan & Meinardi, 2005; Kyvsgaard & Murrell, 2005).

Meat inspectors

Meat inspection in larger slaughterhouses is in most countries under the veterinary authority of the Agricultural Ministry. The authority and obligation to carry out meat inspection in the smaller towns and communities may vary between countries, belonging either to local municipal government, the Agricultural Ministry or to the Ministry of Health. Local police may even be involved when meat is condemned. The meat inspectors may have other duties and will often have very different educational backgrounds. Proper training is therefore crucial.

The role of health workers

The primary health worker plays a central role both in the identification of human carriers and in the promotion of better hygienic practices in the community.

The role of schools

Taeniasis/cysticercosis is an appropriate subject to be introduced into schools along with discussions on food hygiene, food habits, environmental sanitation, man/animal relationships, life cycles of the organisms and their zoonotic importance. In many endemic areas this is an important opportunity for education to reach isolated farms. The preparation of teachers to become active health educators should be encouraged.

Training of health workers and schoolteachers

As far as possible, health educators should be drawn from the community in which they will be working. Everyone involved directly or indirectly in preventing taeniasis/cysticercosis must participate in carrying out public health education. It is, therefore, essential that this subject should have an important place in staff training. Such training should be planned and preferably imparted by a specialist, who should also advise on the selection of appropriate educational methods and the preparation of educational material suited to local conditions and to the various phases of the programme. The general training that health workers may have received in schools of public health also needs to be supplemented with briefings on the various aspects of the local situation. It is useful to prepare and distribute a poster, booklet or manual dealing with the technical, administrative and educational aspects of the programme. This can then be used by all persons involved in the project, including lay members of committees or other groups set up to obtain public cooperation and support. A manual helps to avoid confusion caused by different answers to the same questions given by different people.

The role of pharmacists

Pharmacists play an important role locally, because they sell taenicides, often without medical prescription, and are asked to diagnose taeniasis. They can be actively involved in health education particularly in the supply of educational materials. The educational curriculum of pharmacists should include a course of lectures on diagnosis, treatment, prevention and control of taeniasis/cysticercosis.

Training of the public

Farmers

Farmers should be informed of the risks associated with allowing pigs to have access to human faeces, and the use of human sewage for fertilization and/or irrigation of pasture, and they should be instructed on the benefits of providing effective toilet facilities for their own and worker's families. Therefore, they should be convinced of the importance of: (i) having all cases of taeniasis reported and properly treated; and (ii) using effective toilets when available or, if not available, avoiding defecation in places either directly accessible to susceptible animals or with potential for contaminating their feed.

Pig owners should be informed of the life cycle and the health risks to their families and to the consumers of the meat they produce. They should also be informed of the economic implications (possible closure of their small business by the health authorities and the loss of customers). Sometimes the best way to involve these animal owners is through their children, who can be taught the life cycle of these parasites and the means to prevent infection at school.

These animal owners should also be advised to have their animals inspected at slaughter, but if this is not possible, to learn how to detect cysticerci in the meat and to use the infected meat only if properly treated by cooking or freezing. They also must learn to clean all tools used to cut the meat, in order to prevent the transfer of cysticerci. They should also be persuaded to report and have treated all cases of taeniasis occurring to themselves or to their families.

Butchers

Butchers should be: (i) required to cooperate in the veterinary inspection to detect cysticerci; (ii) trained to detect cysticerci, and properly treat the infected meat, if veterinary inspection is not available; and (iii) required to avoid tasting, eating or selling suspect, untreated raw meat.

Food handlers and consumers

Food handlers should be educated to: (i) look for cysticerci and use infected meat only if it has been previously treated by freezing or cooking; (ii) use suspect (uninspected) meat only if it has been previously treated by freezing or thorough cooking; (iii) thoroughly clean hands, and all kitchen tools (e.g. knives, chopping-boards, etc.) which have been used in preparation of meat; and (iv) avoid tasting raw or insufficiently cooked, infected or suspect meat.

Persons involved in home slaughtering

Some people raise pigs for home slaughter and distribute meat to their families or to local consumers. This may create urban foci as well as act to disseminate infection to rural areas. This is one of the activities where education is most needed in the village situation, as it is probable, currently, that the carcasses have not been inspected.

Community education or prevention

All members of the community should be informed of the life cycles and of the public health and economic impacts of these parasites. They should be encouraged to: (i) report and have treated all cases of taeniasis; (ii) insist that proper public and private toilets with effective sewage disposal are made available and are used; (iii) keep pigs in pens or behind fences; and (iv) insist on the adequate meat inspection services.

Campers and tourists

These groups are often exposed to taeniasis because they may eat raw or improperly cooked meat. Because they frequently defecate in the fields or by the roadside they are an important group that should be informed about the life cycle of the parasite; and advised to: (i) refrain from eating unsafe, raw beef or pork in countries where cysticercosis is endemic, (ii) inspect their faeces for tapeworm proglottids and report for treatment; and (iii) use toilets when available; if these are not available, then they should avoid defecating in places accessible to cattle and pigs, or bury their faeces.

Hunters

They have responsibilities similar to campers and tourists in general, particularly in the use of uninspected meat from the killed animals (pigs) as food for their families or for local consumers. Hunters should be advised: (i) to have wild pig meat properly inspected and, if it is found to be infected, to have this meat properly treated by cooking or freezing; (ii) to learn how to detect cysticerci, if inspection is not feasible; and (iii) to cook the meat thoroughly and avoid tasting before it is cooked.

Exploiting media for local education programmes

The educational material used should take into full consideration the beliefs, perceptions, behaviour, expectations and needs of the people (felt and unfelt). This highlights the need to carry out preliminary cultural and socio-economic studies to ensure that the information imparted will be accepted by each target group (Sanchez & Fairfield, 2003). There is a need to measure the impact of each educational programme to ensure that it does meet the needs and cooperation capabilities of the target group.

A potentially powerful use of the electronic media for prevention and control education efforts is in training the educators in the project with interactive media presentations or tutorials. The use of such new technologies can greatly extend and enhance education materials traditionally employed in health education programmes. A recent project on porcine cysticercosis in The United Republic of Tanzania expanded the use of electronic media options by introducing an educational video to inform the rural communities of the health risks and prevention of T. solium infections (Rimm, 2003). The product of this research was a video that could be taken to even very remote locations and presented to community members either as a VHS videotape (with television screen) or with a DVD player and an LCD projector.

TASKS FOR CONTROL PROGRAMME STAFF, COOPERATORS AND STAKEHOLDERS WHICH REFLECT THE SKILLS AND KNOWLEDGE NEEDED (PAWLOWSKI, ALLAN & MEINARDI, 2005)

Health policy-makers

Collect all possible information on medical and economic importance of taeniasis/cysticercosis in a country and consider a need, priority and feasibility of undertaking control measures.

Create a positive atmosphere from all interested bodies, including mass media, about the necessity of implementation of control measures against Taenia solium taeniasis and cysticercosis.

Select the optimal ways of implementation of the control measures in a country and designate person(s) responsible for its coordination and implementation.

Regularly examine and evaluate the progress in control activities.

Public health officers

Establish person(s) responsible for implementation of control measures and the mechanisms of periodical evaluation of control activities.

Collect hard data on taeniasis/cysticercosis from medical, veterinary and research institutions and create or strengthen existing information system.

Define endemic areas or foci of taeniasis/cysticercosis as well as local resources (personnel and funds) necessary for successful control.

Train medical, laboratory and veterinary services in implementation of the control measures.

Promote a cooperation of the medical, veterinary and non-medical institutions in implementation of control measures.

Strengthen laboratory diagnostic base for identifying Taenia proglottids and/or finding specific coproantigens or Taenia eggs.

Ensure the availability of effective and cheap taenicides listed in the essential drugs list and decide what to do if the drugs are not available, when needed.

Medical personnel

Include training in diagnosis, treatment, prevention and control of Taenia solium infections in academic curricula or postgraduate teaching, and organize special courses related to the control measures.

Keep medical personnel informed about the basic rules of the control measures.

Try to organize, in cooperation with veterinary services, an active search for human carriers in Taenia solium foci and endemic areas.

Ensure taenicide availability and their constant supply.

Treat suspected and confirmed cases of taeniasis.

Evaluate, in cooperation with veterinary services, the progress in local implementation of the control measures.

Take part in educational activities addressed to the population in endemic areas.

Inform health authorities if taenicide drugs are not available when needed.

Analyse the amount of taenicides being used in an area as one of the indicators of implementation of control measures.

Veterinary services

Promote meat inspection and analyse the infection rate in pigs and the origin of cysticercotic pigs diagnosed locally.

Try to organize examination of pigs for cysticerci before slaughter and instruct farmers and rural people what to do to avoid infection in humans and pigs.

Identify local foci of taeniasis/cysticercosis and ask medical services to treat the diagnosed or suspected tapeworm carriers.

Inform veterinary authorities about the local epidemiological situation and control measures being undertaken.

Education Experts

Collect educational material (basic information on taeniasis/cysticercosis and epilepsy) as well as data on the occurrence of Taenia solium taeniasis and cysticercosis, and frequency of epilepsy.

Distribute and use available educational materials and invite the mass media and schoolteachers to include taeniasis/cysticercosis prevention and control measures in their health education activities.

Ensure that anyone who wants to be involved in health education knows where educational materials and support can be obtained.

Primary health workers

Get the support of the local community leaders for implementation of taeniasis/cysticercosis control measures.

Collect information on cysticercosis in humans and pigs and cases of epilepsy in the area and pass the information to the appropriate health authorities and control programme leaders.

Identify, in cooperation with veterinary services, the local foci of Taenia solium infection.

Educate farmers how to prevent cysticercosis in humans and pigs, emphasizing the risk of epilepsy and economic losses.

CONCLUSIONS

Control of neurocysticercosis from T. solium infections will require a multidisciplinary and multilevel approach because of the complex nature of it epidemiology. A control programme will necessitate establishing a national organization that helps and guides the local effort. The control programme will also demand cooperation and participation by the veterinary, medical and public health sectors. This complex organization of experts and stakeholders must be provided with, in addition to resources, a solid understanding of the epidemiology and biology of the zoonosis, and the rationale for the control strategy that is to be pursued. In addition to basic parasitology of T. solium, a good understanding of the risks associated animal husbandry and human behavioural practices, and the economics of pig production and marketing is essential. Important to the success of a programme is attention to management and coordination of the various components of the control organization. Therefore, a good deal of effort and investment in training and indoctrination of all participants in the overall control programme will be required upfront. Even pilot or demonstration control projects will require substantial capacity building. Without this level of preparation, controlling this zoonosis, which is so dependent upon long-established risky animal rearing and cultural traits, will remain nearly intractable.

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