PREVALENCE OF TOXOPLASMA GONDII ANTIBODIES IN LIBYAN SHEEP (FAT-TAILED BARBARY)

Dept. of Parasitology,

Faculty of Veterinary Medicine, AlfatehUniversity.

Prevalence of Toxoplasma gondii antibodies in Libyan Sheep

(Fat-tailed barbary)

(With 2 Tables)

By

K.M. EL-Gomati; A.M. Rashed; A.S. ELNaas and M.M. ELSaid*

*Dept. of Parasitology, Faculty of Medical Technique, AlfatehUniversity,

P.O. Box 13662-Tripoli-Libya.

(Received at 3/9/2008)

مدى إنتشار الاجسام المضادة للتوکسوبلازما قوندا

في الأغنام الليبية (البربري)

خيرية مفتاح القماطى ، احمد محمد راشد ، عدنان سالم النعاس ،

محمد محمد السيد

لقد شملت هده الدراسة على 253 عينة من مصل الدم لفحص الأجسام المضادة لتعيين انتشار التوکسوبلازما قوندا في الأغنام الليبية (البربري) وذلک بواسطة إختبـار الـدم (latex agglutination test) وکانت نسبة الإصابة 103(40.71%). وکانت کذلک نسبة إنتشار الأجسام المضادة للتوکسوبلازما قوندا عالية في الأغنام البالغة (≥ سنة واحدة) وأيضا کانت في الإناث أکثر من الذکور. تشير هذه النتائج بأن التوکسوبلازما قوندا في الأغنام کانت عالية واسعة الانتشار في منطقة طرابلس.

Summary

This study was carried out in order to determine the prevalence of Toxoplasma gondii antibodies in Libyan sheep. A total of 253 sera taken from sheep were examined using a latex agglutination test. Out of 253 samples tested 103 (40.71%) were determined as seropositive. The prevalence of Toxoplasma antibodies was higher in adult sheep         (≥1-year-old), and in female than male. These results indicate that ovine toxoplasmosis is widespread in Tripoli area.                                                                                      

Key words: Toxoplasma gondii, antibodies, Libyan sheep.

Introduction

          Toxoplasma gondii is an obligatory intracellular protozoan parasite which appears to have broad host specificity. Cats and wild felines are the only definitive host while all other warm- blooded animals including human are intermediate hosts. Infection is acquired by ingestion of oocysts excreted by cats that contaminate food or water (Nissapatorn et al., 2004). Cysts formed in sheep and other animals are also sources of infection for human beings too (Tenter et al., 2000). Congenital transmission also occur when an uninfected mother acquires primary infection during pregnancy (Nissapatorn et al., 2004).

In human the disease is widespread and it is usually asymptomatic, but in some cases it is characterized by adenopathy, fever and fatigue, however it can have serious consequences in fetuses, neonates and in immunocompromised individuals (Nissapatorn et al., 2004).

Toxoplasma infection has a major economic impact on sheep resulting in prenatal deaths, abortion, fetal absorption and stillbirths (Masala et al., 2003).

The seroprevalence of toxoplasmosis in sheep has been reported in several parts around the world. The prevalence rates have been varied among countries and diagnostic methods used (Tenter et al., 2000) Latex agglutination test was used by several researchers for the detection of seroprevalence of Toxoplasma infection among sheep. (Sanad and Alohabban 2007, Oncel et al., 2005, Helmick et al., 2002, Hashemi-Fesharki, 1996, Zaki, 1995, Hoghooghi-Rad and Afraa, 1993 and Trees et al., 1989)

Although human toxoplasmosis in Libya has been reported in Tripoli by Khadre and Elnageh (1987) and in Benghazi by Kassem and Morsy (1991) there is little available literature about its prevalence among sheep.

The aim of the present work was to carry out preliminary study to determine the prevalence of Toxoplasma gondii among Fat-tailed Barbary sheep in Tripoly, Libya

Materials and Methods

  Animals

The present study included a total number of 253 sheep (Fat-tailed Barbary), of both sexes, coming from different regions and slaughtered in the abattoirs in city of Tripoli. The age of study group ranged from 6 months to 7years old.

Samples

Blood was collected in tubes without anticoagulant directly from the jugular vein at the time of slaughtering. The samples were allowed to clot (2 hours), centrifuged at 3000g for 5 minute and stored at -20°C till testing.

Serological testing

Serum samples were tested using latex agglutination test (toxocell latex Spain) according to the procedure listed by the manufactured company. Allowing the reagents to reach room temperature, 50ml of the serum (or one drop of control) were placed on one section of the slide. After shaking the reagent vial one drop of reagent was added next to the drop of sample. Both drops were mixed with a stirrer till cover the whole surface of the slide section, the slide was then rotated for 5 minutes manually or on a rotary shaker set at 80-100/rpm. Results were determined by the presence or absence of agglutination.

Results

1- Out of 253 serum samples examined in this study a total of 103 (40.71%) were found to be seropositive. The association of age with the presence of infection revealed that seroprevalence was the highest in ≥1-year-old age group when compared with < 1year (Table 1)

Table1: Toxolasma gondii infection in relation to age.     

2 - A total of 63 (49.2%) out of 128 females and a total of 40 (32.0%) out of 125 males sheep tested were seropositive. Seroprevalence was the highest in females when compared with male as shown in Table 2.

Table 2: Toxoplasma gondii infection in relation to sex.

Discussion

Toxoplasmosis is a zoonotic disease caused by Toxoplasma gondii and has been known in many countries since 1908 (Dubey and Beattie, 1988). Toxoplasma gondii in sheep is distributed world wide, with prevalence rates ranging up to 100% in different countries (Dubey and Beattie, 1988; Tenter et al., 2000).

The prevalence of 40,71% for Toxoplasma gondii antibodies found in this study is lower than those found in Ethiopia (56%), Turkey (65,08%) and Italy (77,8%), (Negash et al., 2004, Oncel et al., 2005, Fusco, et al., 2007). On the other hand it is higher than those found in Bangladesh (17.65%), Brazil (18.75%), Iran (22.85%), Tripoli (13,5) and  Morocco(27.6%), (Samad, et al., 1993; Pita Gondim, et al., 1999;  Zia Ali et al., 2007;  Gusbi, 1986; Sawadogo et al., 2005)

The difference observed could be due to the sampling techniques husbandry methods used in the different regions, frequency of cats on farms. Also the climatic variation has a role in Toxoplasma distribution as the prevalence of toxoplasmosis is higher in warm, moist as compared to cold, dry ones. This is attributed to the longer viability of  T. gondii oocysts in moist or humid environments (Dubey, 1994).

The present study showed elevation in the prevalence of Toxoplasma infection in sheep in Tripoli area (40.71%) as compared with that done in the same area by the same technique by Gusbi (1986) (13,5%), which may results on increase the risk of human infection.

In the present work, LAT was used for the detection of Toxoplasma. The LAT is a sensitive, reliable and rapidly responsive serological test for the detection of Toxoplasma infection in sheep. The LAT showed rapid response with antibody first appearing by two to three weeks after infection (Trees et al., 1989).

This result showed that age group is an important factor. Older sheep were found to have a higher infection rate than younger ones. This result is similar to that of Caballero-Ortega et al. (2008) who found that older animals were more frequently positive and with a stronger response than young ones. In addition Natale et al. (2007), Dumeter,     et al. (2006) indicated that ovine toxoplasmosis seroprevalence was generally increasing according to age and was significantly lower in animals younger than one year. Similar results were obtaind in the present study where the highest prevalence was found in sheep more than one year old.  

This study also showed that the prevalence of Toxopasma gondii antibodies in ewes was higher than rams, this is similar to those reported in Ghana and Saudi Arabia (Van der puije et al., 2000, Sanad and ALghabban, 2007) and differs from that of Caballero-Ortega et al. (2008), who observed no differences between male and female sheep.

Finally, the results of this study confirm the presence of Toxoplasma  gondii antibodies in Libyan sheep. Toxoplasma infection among animals is of great importance, because some of the infected animals play a distinct role as a source of human infection.

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