CHAPTER ONE

1.0 Introduction

           Cysticercosis remains as important health problem in developing countries. Its transmission is related to soil contamination with human faces. This parasitosis is found in African, Asian and Latin America, where the greatest incidences are seen in mexico and brazil.  

         Human cysticercosis is acquired from the ingestion of ova of T. solium, excreted by human carries in their faces, followed by the development of cyst in human tissue. The risk of contamination with taenia ova is related to the contact with T. solium carriers. Recently, it has been shown that in humans, the most common route of infection is ingestion of T. soliumeggs from contaminated food or water. In United States of American and Europe, the frequency of cysticercosis is increasing due to increasing immigration and more frequent travels to endemic regions. The infected individual becomes a carrier and source of infections by oral fecal contamination.

        According to the world health organization (WHO), more than 2million people harbor the adult tapeworm and many more are infected with cysticerci (Garcia and Del brutto, 2000). These authors also indicated that neurocysticercosis is an important public health problem as it affects people of productive ages and causes an estimated 50,000 deaths every years and many times that number of patients are left with irreversible brain damage.

        The disease also causes important economic losses in countries where it is endemic; more than 60millions dollars per year in Mexico only for contamination of parasitized carcasses (Fluzeby 1998). According to Zoli, et al., (2003), economic estimates indicate that the annuals losses due to porcine cysticercosis in 10 west and central African countries amount to about 25millions euros, among which 2million for Nigeria. Infected pigs and carcasses are sold cheaper in unofficial meat distribution channels in order to avoid losses from the contamination of infected carcasses (Pawlowski, 1990; Tsang and Wilson, 1995).

          The cost of this parasitosis for humans is very high (treatment, hospitalization, loss of work days). In 1992, it was estimated at 195 million dollars in USA and 3700 dollars per cases in Mexico (Fluzeby, 1998). In addition, it also reduces the availability of proteins to human as a result of carcass contamination. The human population that is most exposed to the disease are those living in rural areas where sanitary condition are not the best. Djou (2001) quoted by Shey-njila, et al., (2003) reported that the cost of diagnosis, hospitalization and treatment of a human cysticercosis case in Cameroon is 170,000CFA (which is beyond the reach of most rural population.

         The rapid expansion of pig farming and pork consumption is raising concern in Nigeria, as it is bound to exacerbate the problems related to T. solium cysticercosis, not only in rural areas where most pig are left, but also in urban areas where infected pork can  be consumed and human carries of the parasite can infect other people. Prevalence of human taeniasis has been reported in Nigeria at 8.6% (Onah, and Chiejina 1995) with 3.7% associated with epilepsy (Asana and Brandt, 2003). Although the recognition of its status as a serious and emerging threat to public health is increasing, the incidence data in humans are very limited owning to a lack of adequate surveillance, monitoring and reporting systems; consequently, epidemiological information is not extensive.

1.2 Statement of the Problem

       Pig farming and pork consumption has gained popularity in the study areas. Most of these activities (farming and consumption) are done openly. Poverty, poor sanitation and contamination with T. solium eggs from tapeworm carries, however autoinfection as a result of the entry of eggs into the stomach due to etroperistalsis or as a result of accidental ingestion of eggs from the hosts own faeces due to contaminated hands is also possible.

           Most worrying is the fact that people do not have to eat pork to become infected with cysticercosis. One can become infected by ingestion of water or foods or from touching surfaces that have become contaminated with the infected faeces.

         This study was designed to investigate this as well as correlating their knowledge about cysticercosis and prevalence of infection due to cysticercosis.

1.3 Justification

Given that the people in the study areas have a cultural attachment to toilet and other activities. Since pig farming and pork consumption has gained acceptance in the area, it became necessary to study the population that are involved in this activity with a view to as certainty the current level of knowledge regarding transmission and in particular cysticercosis.

1.4 Aim  

This study is aimed at determining the prevalence of cysticercosis in badirisa, Adamawa State.

1.5 Objectives

Its specific objectives were to;

1.     Determine the prevalence of cysticercosis among secondary schools in badirisa.

2.     Determine the prevalence of cysticercosis among gender.

3.     Assess the association between prevalence rate of infection and age.

1.6 Research Questions

  1.   Is cysticercosis infection prevalence among secondary schools in badirisa?

  2.  Is gender associated with the prevalence of cysticercosis infection?

  3.  Is cysticercosis infection prevalence among age group?

1.7 Null Hypothesis

      1. Cysticercosis infection is not prevalence among secondary schools in badirisa.

      2. There is no association between gender and cysticercosis infection.

      3. There is no association between age group and prevalence of infection.

1.8 Significance of the Study

 The will provide and also enlighten people on prevalence of the parasite in the study area. Data generated can be used as baseline information in planning control strategies. Finally, it will serve as a reference material to resources while embarking on further resources.                    

1.9 Literature Review

In West Africa, T. solium cysticercosis in pigs and man has been reported in Benin, Burkina-Faso, Ghana, Ivory Coast, Senegal and Togo, and although official data are lacking,T. solium is anticipated to be present in most of the pig-raising regions of other West African countries as well. In some regions of Nigeria, the prevalence of porcine cysticercosis and human taeniosis is quite high (20.5% and 8.6% respectively). Surprisingly, however, no cases of human cysticercosis have been reported, although epilepsy is very common. Large epidemiological surveys have only been carried out in Togo and Benin, where the prevalence of human cysticercosis was 2.4% and 1.3%, respectively (Onah and Chiejina 2004).

In Central Africa, porcine and human cysticercosis are (hyper)-endemic in Rwanda, Burundi, the Democratic Republic of Congo and Cameroon. The parasite also has been reported in pigs in Chad and Angola. Cysticercosis has been shown to be one of the major causes of epilepsy in Cameroon with figures as high as 44.6%. Cameroon is one of the few countries where the taeniosis-cysticercosis complex has been examined more in detail. In the Western province of Cameroon large scale surveys have shown that active cysticercosis is present in 0.4-3 % of the local population and in 11% of the village pigs. However, the prevalence of adult T. solium was only 0.1 %, which underscores the frequency of the T. solium paradox (Andre, et al., 2003).

Based on the available information, a very conservative economic estimate indicates that the annual losses due to porcine cysticercosis in 10 West and Central African countries amount to about 25 million Euros. The financial losses due to human cysticercosis are very difficult to estimate, but are certainly exceeded by the social impact of the disease, especially because of the particular perception of epilepsy in many African communities. It is concluded that the true prevalence of T. solium cysticercosis in pigs and humans in Central and West Africa remains underestimated because of unreliable slaughterhouse data and the lack of awareness and diagnostic facilities in the public health sector                          (Tsang and Wilson 2001).

Two different populations in sayalla, a peruvian village near cusco, known for chicharrones, were surveyed by serology and stool examination to determine the prevalence and epidemiology characteristics of T. solium infection. The chicharrones, were members of families of professionally devoted to the making and selling of chicharrones, was a sample of the general population of the same village. General villagers only occasionally prepare or sell this food product, and then only to their neighbours or relatives. The prevalence of taeniasis was extremely high (8.6%) for the chicharroneros and 3% for the general villages. Seroprevalence for cysticercosis by immune blood was similarly high in both groups (23.3% and 23.8% respectively). Being female, older than 30 and long daily contact with pork were factors strongly associated with positive serologic result for cysticercosis in the chicharrones, whereas males were more frequently seropositive in the general villages group. Antibody reaction to more antigen bond in immune blots and neurologic symptoms were more common among the chicharrones (Victor and Janet 2007). 

Also, in the general villagers group, sero prevalence increased with each  exposure factor, ranging from 9.4% in individuals who did no traise pigs to 50% in the small subgroup that raised pigs,but chered their own animals, sold pork, and  sold chicharrones, suggesting that these activities are related to increased risk for tapeworm or larval infection (Rebecca, 2006).

 In Nigeria, T. solium cysticercosis is a problem in rural areas where most pigs are kept and in urban areas where infected pork can be consumed.  Enzyme linked was performed to immunosorbent assays on serum samples collected from pig rearers in Jos, Nigeria, to determine the prevalence of IgG antibodies. Results: Of 125 subjects tested, 12 (9.6%) were positive for T. solium. Seroprevalence did not differ significantly (P>0.05) according to education, age, occupation, study location, gender or whether the subjects consumed pork.  However, a statistical difference (P<0.05) in seroprevalence was observed according to type and availability of toilet used, personal hygiene after using the toilet, and type of pig management practiced. Females were about two times more likely to be seroprevalent than males (OR=1.7; 95% CI= 0.43-6.67; P=0.4) and subjects who consumed pork were four times more likely to have anti T. solium antibodies than those who did not eat pork (OR=4.2; 95%CI=0.52-33.57; P=0.2). Those who defecated in the bush were 8.3 times more likely to suffer from T. solium infection than those who used water system toilets (OR=8.3; 95%CI=1.56-43.7; P=0.01). Subjects who did not wash their hands after defecating were 6 times more likely to contract T. solium compared to those who washed their hands with water ( OR=5.5; 95% CI=1.39-21.89; P=0.01). Conclusion: Our results show that using a toilet and practicing good personal hygiene can reduce cases of T. solium infection in a community (Eugene, and Joshua, 2007).

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