Introduction

Meat borne diseases are important from public health and economic point of view. Very recently, Pal (2012) highlighted the public health risks due to ingestion of raw meats. He described many infections including sarcocystosis transmitted through raw meat. Sarcocystis species are protozoan parasites of livestock, which infect humans as well many species of animals such as cattle, pig, goat, sheep, horse, baboon, chimpanzee, and monkey (Dubey et al.,1989; Tenter,1995,Fayer,2004; Endeshaw,2005 and Pal,2007).The life cycle of Sarcocystis spp. has an obligatory two host life cycle with an intermediate and a definitive host that mainly influence the human health condition. Humans can get intestinal infection through the consumption of raw or undercooked beef or pork containing sarcocysts; and muscular sarcocystosis  occurs when food or water contaminated with sporocysts is accidentally ingested (Frenkel,1997).The animal muscular infection is common throughout the world and follows ingestion of food or water contaminated with sporocysts.

Humans can serve as both intermediate and definitive hosts for different species of Sarcocystis. In cases of intestinal sarcocystosis, when humans serve as the definitive hosts, the spectrum of infections is often asymptomatic, transient and moderately severe disease. Occasionally, abdominal pain, mild fever, diarrhoea, chills, nausea, vomiting and respiratory problems may occur (Pal,2007) .When humans become infected with Sarcocysts spp. of non-human species, the infections are end result in muscle cysts; and the symptoms such as myalgia, muscle weakness and transitory edema are noticed. Sarcocystis spp. formerly considered as Isospora hominis, is now classified as Sarcocystis species (Current et al., 1999).More than 100 species of Sarcocystis have been recognized, and they have worldwide distribution, but individual species may be found in specific geographic regions (Bunyaratvej et al., 2007). Human  sarcocystosis is caused by Sarcocystis hominis and S. suihominis (Pal, 2007).Man is the definitive host for S.hominis and S.suihominis ; and intermediate hosts for S. homonis and S. suihominis are cattle and pig, respectively (Markus,1978). Humans acquire intestinal sarcocystosis after eating raw or undercooked or inadequately cooked or partially roasted pork or beef containing numerous mature sarcocysts ( Frenkel, 2000 and Pal,2007 ).

The prevalence of intestinal sarcocystosis has been reported worldwide and the incidence is estimated to be 6-10% in  human population ( Fayer,2004.,CFSPH,2005 and Despotes-Livage and Datty,2005 ).Most of the intestinal Sarcocystis spp. infections have been found  in cultures where raw meat is commonly eaten ,and  poor hygiene is practiced. In Tibet, the rate for S. hominis was 21.8 %  while that for S. suihominis ranged from 0.06 % to 70 %. The high rate of S. hominis infection in Tibet reflects that custom of eating raw beef is very common as compared to pork consumption. Human muscular sarcocystosis infection has been reported in Southeast Asia, Africa, and South America ( Beaver et al.,1979;Wong and Pathmanathan,1992 and Frenkel,1999).About 30 cases of human muscular sarcocystosis have been reported, most of them in Malaysia, where the prevalence of sarcocystosis in general was 21 % in routine autopsy (Wong and Pathmanathan,1992).

Published data on the prevalence of sarcocystosis in Ethiopia are scanty. The prevalence of Sarcocystis infection was reported 3.3 % by Endeshaw and co-workers (2007) and 10.2% from Sirba Abaya and (1.2%) from Arsi elementary schools by Kebede (2005).On the other hand, the prevalence of this parasite in Ethiopia was also reported in domestic animals; and the infection rate was above 90% in sheep, above 80% in cattle and goats while it was lower in donkeys and chickens (Woldemeskel and Gebreab, 1996).

Intestinal sarcocystosis can be diagnosed by observation of sporulated sporocysts or oocysts in stool specimen by using formol-ether sedimentation or zinc sulfate flotation. Sarcocysts may be found in the muscles by microscopic examination in tissue specimens. Oocysts measure 15.5 × 20 um and sporocysts 12 × 6 um. ( Juckett,1996).However, in most health facilities in developing countries like Ethiopia, where other intestinal parasites are extensive, but the reporting of Sarcocystis infections have been over looked by the laboratory technicians and physicians.

Although in developing country like Ethiopia, the social and cultural practice of the people have the habit to consume the raw beef. However, there are few reports on Sarcocystis infection in humans as well as in domestic animals (Woldemeskel and Gebreab1996; Kebede, 2005 and Endeshaw et al. (2007). Therefore, the objective of this study was to determine the prevalence of Sarcocystis infection in humans using laboratory investigation of stool samples in selected health facilities of Southern Ethiopia. 

Materials and Methods

Study Area and Period

The study was conducted from September 2009 to June 2010 in selected health facilities in     Southern Ethiopia. The study was carried out in Hosanna, Butajira,Wulkita, Hawassa, Dilla , Wolaita-Sodo and Arba-minch. Based on the 2007 Census, conducted by the Central Statistical Agency of Ethiopia (CSA), the Southern Nations Nationalities and Peoples Region (SNNPR) has an estimated total population of 15,042,531, of whom 7,482,051 were men and 7,560,480 women. 13,496,821 or 89.72% of the population are estimated to be rural inhabitants, while 1,545,710 or 10.28% are urban; this makes the SNNPR Ethiopia’s most rural region. With an estimated area of 112,343.19 square kilometers, this region has an estimated density of 133.9 people per square kilometer.

Study Design Facility based cross sectional study was conducted to determine the prevalence of sarcocystosis in selected health facilities in Southern Ethiopia.

Selection of Study Subjects: When this study was carried out, all patients requested stool examination in health facilities enrolled in the following annual Ethiopian religious festival (Christmas and Easter) period were purposely selected during the study period. Informed consent was obtained from the patients or families for their children.

Stool Sample Collection and Examination: A single fresh stool was collected with a labeled stool cup from patients visiting health facilities following standard procedures; and the health behavior data from self administrated questionnaire were collected at the same time.  Fresh stool specimens were examined with direct saline mount for motile trophozoites. Part of the sample was preserved in sodium acetate- acetic acid formalin in a proportion of 1g of stool in 3 ml of SAF and was transported to the Ethiopian Health Nutrition Research Institute Laboratory, Addis Ababa for formol-ether concentration technique (Scholten and Young, 1974). A preserved stool sample was processed as described by Ritchie (1948) with some modification. Briefly, one gram of stool sample was mixed with 8 ml of 10% formalin and crushed well. It was sieved with double layer cotton gauze into 15 ml conical centrifuge test tube. Three ml of diethyl ether was added and shaken and then centrifuged for two minutes at 2000 rpm. The supernatant was discarded and the sediment observed for the presence of ova and/or parasites under the light microscope at a magnification of 100X and 400X.

Data were entered into a computer and analyzed using SPSS windows version 16. Descriptive statistics was used to give a clear picture of background characteristics like age, sex, and occupation. The relationships between proportion of Sarcocystis parasitism and determinant factors for intestinal parasitism such as age and sex were analyzed. Chi-square test was used to see crude association of sex and the proportion of intestinal parasitism. P-value less than 0.05 was considered as statistically significant (Thrusfield, 2005).

The study had ethical clearance from the Ethiopian Health and Nutrition Research Institute   Ethical Committee, Addis Ababa. Written permission was obtained from the Town Administrative Officer prior to start the study. Verbal consent was obtained from each individual before conducting interview and sample collection. The procedure was non invasive and has no physical harm to the study subjects. Patient with positive results were treated with appropriate treatment, and the drugs were administered by clinicians working in the study health facilities.

Results

Out of a total of 223 patients examined, 133 (59.64%) were found to be infected for one or more of the intestinal parasites. Among all the participants, 103 (46.2%) were males. The predominant parasites involved in study population was multiple infections which was observed in 24 (10.8%) of the study population followed by Entamoeba histolytica /E.dispar was 20 (8.9%) and Ascaris lumbricoides (8.5 %) (Table 1).

Table 1.Number of patients positive for one or more parasites among, 223 subjects in different health facilities of south Ethiopia (September2009-November 2010)

*Multiple infections were found

Table 2 .Distribution of Sarcocystis spp. infection   between different study sites of south Ethiopia (September 2009-November 2010)

Table 3.Potential risk factors for the prevalence of Sarcocystis infection among 223 study subjects (Sep.2009-Nov 2010)

The prevalence of sarcocystosis was 14 (6.3 %) and out of the total positive cases, 2 (14.3%) were males and 12 (85.7%) were females. The difference between male and females was statistically significant (p<0.05). Individuals aged 0 to 15 years had the highest infection rate (71.4%) , with the second highest rates of infection among those aged 16-20 years and above 40 years, in which the rates were equal (14.3%). The majority of the study participants (85.7%) were followers of the Christianity religion; and116 (52%) of the study population was illiterate.

Out of the total visited health facilities, the highest prevalence rate was observed in Hosanna (26.1%) followed in Wolaita-Sodo (14.3%) and Dilla (2.9%) (Table2). The potential risk factors for the prevalence of sarcocystosis among 223 subjects is summarized in Table 3.Higher prevalence was recorded in females, Christians, younger age groups ( less than 15 years) , illiterate, handling livestock and no treatment of drinking water. This study revealed that 71.4% of cases reported had consumed raw beef (Table 3).

Discussion

Sarcocystosis is a meat borne parasitic disease which is reported from many regions of the world (Pal, 2007). The prevalence of Sarcocystis infection varies from country to country and even differs within the same country from area to area. Such variations depend upon the habit of raw meat consumption, personal and environmental hygiene and other factors (Markus, 1978; Dubey et al, 1989 and Wong and Pathmananthan, 1992).

Sarcocystosis   is not well reported in Ethiopia due to under diagnosis in different health facilities. It is mostly identified from the beef rather than pig meat. This is due to fact that Ethiopians follow religion that prohibits them from the consumption of the pork. Raw beef is a highly preferable dish of the people in the study area as they much enjoy consuming raw meat.

In the present study, the prevalence of Sarcocystis spp. infection was significantly different between males and females (p<0.05), as females were more infected than males.  The possible explanation for our findings may be the increased opportunity of exposure for females to handle the contaminated meat.

The results of this study showed 6.3% prevalence of intestinal sarcocystosis infection. This was lower than the findings of Kebede (2005) who mentioned 10.2% prevalence in the primary school children from Sirba Abaya. This may, however, be due to differences in the study population and the study localities under consideration.

In the present study, higher rate of Sarcocystis infection (74.4%) was found in the school age children. Our findings do not go parallel with the earlier studies done among the school children in Ethiopia by Kebede (2005) who reported 10.2% and 1.2 % infection rate in primary school children in Sirba Abaya and Arsi, respectively. Limitation of this investigation was scarce resources to carry out comprehensive studies. The observed higher proportion of Sarcocystis infection in the Christian community in this study could be justified by the fact that the raw meat is more favorite dish among the Christians in Ethiopia.  

Since Sarcocystis spp. is an important protozoan parasite as revealed by the findings of our present investigation, it is advisable to undertake further detailed studies with large numbers of samples from various part of the country particularly, from the immunocompromised patients.

Public health facilities must give emphasis on providing health education to the people that aims at promoting consumption of properly cooked food particularly the meat to control sarcocystosis   and also other meat borne zoonoses. This will certainly reduce the incidence and prevalence of meat borne diseases which pose great public health hazards to several countries of the world.

Acknowledgements

This study was financially supported by Ethiopian Health Nutrition Research Institute, Addis Ababa, Ethiopia. We thank to the selected health facilities staffs and administrators for their cooperation throughout the study; and to Dr. Zelalem Kebede and Mr.Tesfaye Mengesha for their constructive suggestions during the writing of the manuscript.

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