Prevalence , organ distribution , viability and socioeconomic implication of bovine cysticercosis / teniasis , Ethiopia

Bovine cysticercosis refers to the infection of cattle with metacestodes of the human tapeworm (9). It is a major problem for producers in sub-Saharan Africa. The clinical effect of cysticercosis on infected animals is generally not significant, however, similarly to the effect on human health. Many cases of teniasis in humans are asymptomatic, except for some anal pruritus due to emerging tapeworm segments but with severe infection human beings may experience loss of weight, anorexia, abdominal discomfort, and digestive upset (6). Economic losses may be high due to the condemnation of heavily infected carcasses and the necessity to freeze or boil infected meat; losses may also occur from export restrictions. Taenia saginata occurs in the small intestine of humans and the metacestode (Cysticercus bovis) is found in cattle. Most incidents in cattle arise as a result of direct exposure to proglottids shed from farm workers, but there have been some reports of large scale outbreaks resulting from sewage-contaminated feed or forage (13). Even developed countries, where the disease has a very low prevalence, have to face the problem of egg surviving in sewage (4). Globally, there are 77 million carriers of bovine teniasis and about 40% of them live in Africa. The teniasis prevalence of 64.2% reported by Abunna et al. (1) and of 51.1% reported by Regassa et al. (10) based on questionnaire surveys revealed that it is a well-known disease in Ethiopia. On the other hand, the prevalence of cysticercosis in cattle was reported to be 26.25% at Awassa’s abattoir (2), 13.3% at Wolaita Sodo’s abattoir (10), and 4.4% at Jimma’s abattoir (8). No study had been conducted in Yirgalem with regard to bovine cysticercosis/ ■ P A TH O LO G IE P A R A SI TA IR E


■ INTRODUCTION
Bovine cysticercosis refers to the infection of cattle with metacestodes of the human tapeworm (9).It is a major problem for producers in sub-Saharan Africa.The clinical effect of cysticercosis on infected animals is generally not significant, however, similarly to the effect on human health.Many cases of teniasis in humans are asymptomatic, except for some anal pruritus due to emerging tapeworm segments but with severe infection human beings may experience loss of weight, anorexia, abdominal discomfort, and digestive upset (6).Economic losses may be high due to the condemnation of heavily infected carcasses and the necessity to freeze or boil infected meat; losses may also occur from export restrictions.Taenia saginata occurs in the small intestine of humans and the metacestode (Cysticercus bovis) is found in cattle.Most incidents in cattle arise as a result of direct exposure to proglottids shed from farm workers, but there have been some reports of large scale outbreaks resulting from sewage-contaminated feed or forage (13).
Even developed countries, where the disease has a very low prevalence, have to face the problem of egg surviving in sewage (4).Globally, there are 77 million carriers of bovine teniasis and about 40% of them live in Africa.The teniasis prevalence of 64.2% reported by Abunna et al. (1) and of 51.1% reported by Regassa et al. (10) based on questionnaire surveys revealed that it is a well-known disease in Ethiopia.On the other hand, the prevalence of cysticercosis in cattle was reported to be 26.25% at Awassa's abattoir (2), 13.3% at Wolaita Sodo's abattoir (10), and 4.4% at Jimma's abattoir (8) Human teniasis prevalence showed significant differences (p < 0.05) in relation to sex, religion, occupational risk, marital status and raw meat consumption.Thus, men (p = 0.001), Christians (p < 0.001), occupationally high-risk groups (p < 0.001), married persons (p = 0.016) and raw meat consumers (p < 0.001) were at higher risk of being affected by teniasis than women, Muslims, occupationally low-risk groups, unmarried persons and cooked-meat consumers, respectively.In this analysis, no statistically significant difference was observed in relation to the age and educational background (p > 0.05).An inventory of pharmaceutical shops revealed the purchase of 472,013 adult teniacidal drug doses for a cost of 1,416,039 Ethiopian Birrs (about 88,500 USD) during a five-year period (2005 to 2009).Mebendazole and niclosamide were the most frequently drugs sold for teniasis treatment, whereas praziquantel was the least sold one.
In conclusion, the study revealed a high prevalence of T. saginata metacestodes in the organs at the abattoir, and highlighted the deeply rooted tradition of raw meat consumption.Authorities should focus on this disease to preserve public health and consequently promote the beef industry in the country.
teniasis.Therefore, the objectives of the present study were to determine the prevalence of Cysticercus bovis in cattle slaughtered at Yirgalem's municipal abattoir and assess the socioeconomic implications of T. saginata in Yirgalem and its surroundings.

Study area
The study was conducted from November 2009 to March 2011 in Yirgalem, located at about 310 km south of Addis Ababa, capital of Ethiopia, at 7° 13' and 8° 56' N latitude and 35° 52' and 37° E longitude.The altitude of the area ranges between 880 and 3358 m above sea level.The total population is about 43,000.Annual rainfall ranges between 1200 and 2000 mm, with 7 and 30°C minimum and maximum annual temperatures, respectively.

Study methodology
A cross-sectional study was conducted on randomly selected animals slaughtered at Yirgalem's abattoir.A total of 400 cattle were sampled and routinely inspected for T. saginata cysticercosis.The study animals originated from the highland sedentary farming system of Arsi and Sidama areas, and Borana and Guji lowland pastoral production system.The breeds of the animals were the local zebu, and the zebu crossbred with Holstein-Friesian.Prior to sampling, each selected animal was given an identification number and data on each animal concerned sex, age, breed and origin.During meat inspection, the identified animals and their respective organs were examined strictly separately to avoid mixing the organs.Meat inspection was made in accordance with the procedures of the Ethiopian Ministry of Agriculture's Meat Inspection Regulation (1972) for the detection of T. saginata cysticercosis.
Visual inspection followed by multi-incisions of 0.5 cm in each organ (heart, shoulder, tongue, liver, kidney, lung and masseter muscle) were made to examine the cysts of T. saginata.Lesions of cysticerci were 5-8 by 3-5 mm, translucid and filled with brownish fluid.T. saginata metacestode samples were transported to the laboratory of Yirgalem Health Centre and Veterinary Clinic.Cyst viability was ascertained by placing the cysts in a normal saline solution with 30% ox bile and incubated at 37°C for 2 h.The cysts were regarded as viable if the scolex evaginated after the incubation period.Examination of the scolex was performed microscopically to determine whether it was C. bovis or C. cameli based on the size of the cysticercus and the absence of hooks on the rostellum of the evaginated cyst (6,14).
A questionnaire survey was administered to 170 randomly-selected volunteer respondents from whom pre-informed consents were obtained.The interviews were conducted personally.The potential risk factors of teniasis, i.e. age, sex, religion, occupation, educational level, raw meat consumption, and marital status, were considered.Occupationally high-risk groups were those who were highly in contact with meat, meat products and animals, such as abattoir workers, butchers, meat inspectors, cooks and farmers.Low-risk groups were arbitrarily selected as those who were not as highly in contact with meat and meat products, i.e. students, teachers, other civil servants and private workers.
An inventory was conducted on eight randomly-selected volunteer pharmaceutical shops from a total of twelve.The annual adult dose of teniacidal drug sales (based on prescriptions and patient complaints) were retrieved from 2005 to 2009 records and analyzed for the socioeconomic significance of teniasis.

Data management and analysis
The abattoir survey, questionnaire and drug inventory data were recorded and a preliminary analysis was carried out with Microsoft Excel.The abattoir data were summarized and prevalences calculated.Anatomical distribution and viability of metacestodes of T. saginata were tabulated.The questionnaire data were also summarized and analyzed to assess the association of potential risk factors of teniasis among different respondents, using Stata logistic regression, version 9, special edition.Inventory data of pharmaceutical shops were summarized with a frequency table.I).Analysis of the abattoir survey showed a significant variation in the anatomical distribution of cysticerci in the organs inspected.Table II shows that the highest proportions of T. saginata cysts were found in the tongue, followed by the masseter muscle, the liver, the shoulder and the heart for a total of 190 cysts detected during inspection.Of these 190 metacestode cysts, 89 (46.84%) were found to be alive, whereas the others 101 (53.16%) were degenerative cysts (Table II).

Of
Among the 170 interviewed volunteer respondents, 119 (70%) had contracted tapeworm infection in the course of their lives.The majority of the respondents consumed raw meat as a result of traditional or cultural practices.The logistic regression analysis of the risk factors showed a statistically significant difference (p < 0.05) in the prevalence of teniasis with regard to sex, religion, occupational risks, marital status and raw meat consumption.In this analysis there was no statistically significant difference (p > 0.05) between the age, religion and educational level (Table III).
An inventory of pharmaceutical shops (pharmacies, drugstores and rural drug vendors) was conducted in the town.Estimates of yearly adult teniacidal drug doses and their costs were recorded through personal interviews with individuals in charge of their sales, using their records for the years 2005-2009.A total of 472,013 adult teniacidal drug doses were sold for a total of 1,416,039 Ethiopian Birrs (about 80,500 USD) (Table IV).Mebendazole (Vermox®) and niclosamide were the most frequently sold drugs for the treatment of teniasis, and praziquantel was the least sold drug.

■ DISCUSSION
The results of the present study reflected both the economic and zoonotic importance of this disease, which is in agreement with the above statements.The prevalence of metacestodes of T. saginata among the carcasses inspected at Yirgalem's abattoir was 12%, which is higher than findings by Dawit  Similarly, no variation was observed (p > 0.05) between people with different educational backgrounds, perhaps because of the deeply rooted tradition of raw and undercooked meat consumption regardless of the educational level.The importance of human teniasis is both socioeconomic and health related.However, evaluation of the economic aspects is very difficult, particularly in developing countries such as Ethiopia, where infected people treat themselves with traditional herbal drugs.One of the possible sources of information to evaluate the financial loss is to carry out inventories of pharmaceutical shops, which may not reflect the actual economic impact of the disease.However, inventories of pharmaceutical shops in Yirgalem that covered five years' records (2005-2009) indicated that 472,013 adult teniacidal drug doses were sold for a total of about 88,500 USD.This shows the teniasis impacts on household financial resources, which could be easily avoided by eating well-cooked meat and using toilets.
This study revealed that bovine cysticercosis/teniasis is a major disease both with regard to public health and socioeconomic aspects.The disease results in financial losses caused by the condemnation of infected organs and downgrading of carcasses, and the considerable costs of human treatments.Therefore, strict routine meat inspections should be conducted so that infected carcasses and organs would be condemned accordingly.Populations should be made more aware of general, personal and environmental hygiene, and means of disease transmission, so that all consumers avoid consumption of raw meat and are encouraged to use toilets for the control of human teniasis and cattle cysticercosis.(10).The majority of the findings in Ethiopia were based on surveys carried out on carcasses subjected to routine meat inspection.Hence, the same limitations shared globally with meat inspection were reflected in this study.Accordingly, the lower prevalence of bovine cysticercosis in this study might be attributed to variations in personal and environmental hygiene, religion, culture, and feeding habits, including beef breeds and their production systems.
The most frequently affected organ with the highest number of cysts was the tongue.The viability test of the cysts also revealed that the tongue harbored the highest number of viable cysts (63.16%), followed by the masseter (44.23%), the liver (41.38%), and the heart (40%).The proportion of tongues affected with metacestodes of T. saginata was higher than that found in Hawassa (10.4%) (2) but agrees with that found in Jimma (40.43%) (8).Generally, the method of meat inspection, the ability of meat inspectors to identify cases, differences in management, the sample size and sampling method, the number of cuts, and other factors can contribute to prevalence variations in bovine cysticercosis.
Of the 170 respondents of the questionnaire survey, 70% had contracted teniasis, which illustrates the significance of teniasis in the population of Yirgalem and agrees with other authors' findings: 64.2% (1), 79.5% (7) and 69.2% (3).A well-formulated questionnaire is an important tool for the detection of T. saginata in the carrier population, in individual cases as in mass investigations (4).The respondents who were questioned in this study disclosed findings of proglottids in their feces, underwears, and a laboratory diagnosis at a health institution indicated the presence of T. saginata.WHO's guidelines ( 14) state that T. saginata is known by its more frequent anal expulsion than T. solium.The supporting evidence of the occurrence of T. saginata rather than T. solium among the respondents was that none of the residents of the town ate pork for religious reasons, confirming the presence of T. saginata and ruling out a possible differential diagnosis of T. solium.
With a 70% prevalence, human teniasis has been a widespread health problem in the study area.In the present study, the prevalence of human teniasis showed significant differences (p < 0.05) according to sex, religion, occupational risk, marital status and raw meat consumption.Men, Christians, occupationally high-risk individuals, married persons and persons who consumed raw meat were at higher odds of contracting teniasis than women, Muslims, occupationally low-risk groups, unmarried persons and cooked-meat consumers, respectively.Thus, infection of humans by T. saginata is mainly due to the habit of eating raw (Kurt) or semi-raw (Kitifo) meat dishes in Ethiopia and raw meat consumption in Cuba (11).
. No study had been conducted in Yirgalem with regard to bovine cysticercosis/ Summary A cross-sectional study was conducted from November 2009 to March 2011 to determine the prevalence of cysticercosis/teniasis and to estimate the treatment cost of the disease in Yirgalem, Ethiopia.Abattoir findings, a questionnaire survey and inventories of pharmaceutical shops were used in the study.Of the 400 inspected animals, 48 (12%) had varying numbers of Cysticercus bovis.The anatomical distribution of the cysts showed that the highest proportions of C. bovis cysts were in the tongue, followed by the masseter muscle, liver, shoulder and heart.Of a total of 190 C. bovis collected during meat inspection, 89 (46.84%) were alive.Viability tests revealed that the tongue harbored the highest number of viable cysts (63.16%), followed by the masseter (44.23%), the liver (41.38%), and the heart (40%).Of the 170 interviewed respondents, 119 (70%) had contracted a Taenia saginata infection, and among them 85% reported using modern drugs, whereas the rest (15%) used traditional drugs.The majority of the respondents consumed raw meat as part of traditional or religious practices.