Trop Anim Health Prod (2008) 40:311–315 DOI 10.1007/s11250-007-9101-6
SHORT COMMUNICATION
Prevalence of antibodies to Toxoplasma gondii infection in humans and domestic animals in Samsun province, Turkey M. Acici & C. Babur & S. Kilic & M. Hokelek & M. Kurt
Accepted: 6 November 2007 / Published online: 27 November 2007 # Springer Science + Business Media B.V. 2007
Keywords Cattle . Human . Sheep . Toxoplasmosis . Turkey Abbreviations ELISA enzyme linked immunosorbent assay ELISA enzyme linked immunosorbent assay IgG immunglobulinG ELISA enzyme linked immunosorbent assay IgM immunglobulin M IgG Immunglobulin G IFAT indirect fluorescent antibody test IHAT indirect hemagglutination test SFT Sabin Feldman dye test M. Acici (*) Department of Parasitoloy, Faculty of Veterinary Medicine, Ondokuzmayıs University, Kurupelit/Samsun, Turkey e-mail:
[email protected] C. Babur : S. Kilic Ministry of Health Refik Saydam Hifzisihha Centre, Ankara, Turkey M. Hokelek Department of Microbiology, Faculty of Medicine, Ondokuzmayıs University, Samsun, Turkey M. Kurt Veterinary Control and Research Institute Parasitology Laboratory, Atakum, Samsun, Turkey
Introduction Toxoplasmosis is one of the more common parasitic zoonoses world-wide. It is caused by T. gondii which is a facultatively heteroxenous protozoan that has developed several potential routes of transmission within and between different host species (Tenter et al. 2000; Sroka 2001). Humans become infected with T. gondii mainly by ingesting uncooked meat containing viable tissue cysts or by ingesting food or water contaminated with oocysts from the faeces of infected cats (Dubey 2004). Transmission may also occur via tachyzoites contained in blood products, tissue transplants or unpasteurised milk (Dubey et al. 1985; Tenter et al. 2000). Apart from causing significant economic losses in animal husbandry, T. gondii also causes toxoplasmosis in humans in Turkey through the consumption of rare or raw meat of infected sheep and cattle (Altıntas et al. 1997a,b; Sevgili et al. 2005). While the parasite has been frequently isolated from sheep meat, it is not so readily isolated from cattle meat (Dubey 1992; Redondo and Innes 1997). Cattle, like deer and horses, are susceptible to infection but are resistant to disease induced by T. gondii. Sheep with toxoplasmosis do not display specific clinical signs but it causes significant economic losses due to prenatal death and abortion. A broad range of serological tests has been developed to diagnose infections with T. gondii in intermediate hosts
312
(Figlioulo et al. 2004; Pereira-Bueno et al. 2004; Pita Gondim et al. 1999). The aim of the present study was to investigate the prevalence of T. gondii in rural areas of Samsun region in naturally exposed sheep and cattle as well as transmission to humans by Sabin Feldman dye test.
Materials and methods According to the Livestock Census of 2000, there were about 204,100 cattle and 218,000 sheep in Samsun province. In this study, serum samples were collected from 95 sheep and 96 cattle. These numbers derived from a predicted 40% toxoplasmosis prevalence, with 5% deviation and 95% confidence interval. The animals were selected from Vezirköprü and Bafra counties by the stratified sampling technique (Ikiz et al. 2000). The study’s serum samples, were taken from a total of 95 sheep from Vezirköprü (3 farms) and Bafra (4 farms) with a flock size of about 150-200 sheep (10-20 sheep from each flock) and 96 cattle from Vezirköprü (9 farms) and Bafra (7 farms) with a herd size of about 15-25 cattle (5-10 cattle from each herd). A total of 72 sera were collected from owners of the animals (2-3 samples from each family) who were in close contact with cattle or sheep. After blood samples were obtained, sera were separated from blood by centrifugation, and stored at 20°C until use. The Sabin Feldman Dye test (SFT) in sheep and other animals was used for titer determination, because it is the basic test used in serological examination of both humans and animals (Dubey 1985). Prior to testing, serum samples were inactivated by heating to 60°C for 60 min (Dubey et al. 1985). Each serum sample was tested at a dilution of 1:16, 1:64, 1:256 and 1:1024. Sera with a titer of 1:16 or greater were considered positive. Statistical analysis was performed using the chi-square test (Thrusfield 1995).
Results From 95 tested samples, 47 sheep (49.47 %) were positive for IgG antibody to T. gondii (SFT ≥1:16) in 7 flocks in Samsun province (Vezirköprü and Bafra). Of these, 38 (80.85%) were in the range 16–64, 6 (12.76%) in the range 128–256 and 3 (6.38%) in the range 512-1024.
Trop Anim Health Prod (2008) 40:311–315
In Vezirköprü, out of 48 sheep tested, 20 (41.66%) reacted positively to T. gondii antigen; in Bafra, 27 (57.44%) sera out of 47 gave positive results. The prevalence of specific IgG antibodies to T gondii in the sheep population did not increase with age (Table 1). There were no differences between both the Bafra and Vezirköprü sheep, and among age groups of sheep (P> 0 05).In cattle, from 96 tested samples, 52 (54.16%) were positive for T. gondii (SFT =1:16). There was no difference in seropositivity between the 10 cattle up to one year old (62.5%) and the 42 cattle (52.5%) older than one year (P>0.05). Of these, 43 (82.69%) were in the titer range 16–64, 7 (13.46%) in the range 128– 256, and 2 (3.84%) in the range 512-1024. On the other hand, seropositivity for cattle was 35 (66.03%) in Vezirköprü, which was significantly different from the 17 (39.53 %) in cattle in Bafra (P0 05). In Vezirköprü, out of 43 farmers tested, 10 persons
Table 1 Serological results for the Sabin Feldman dye test for toxoplasmosis in animals in the Samsun region, Turkey Variables
Region Vezirköprü Bafra Age group Age ≤ 1 Age > 1 Sex Female Male Total
Species Sheep
Cattle
n
n
Prevalence: positive samples (%)
Prevalence: positive samples ( % )
48 20 (41.66) 47 27 (57.44)
53 35 (66.03) 43 17 (39.53)
24 11 (45.83) 71 36 (50.70)
16 10 (62.5) 80 42 (52.5)
84 42 (50.0) 11 5 (45.45) 95 47 (49.47)
82 45 (54.87) 14 7 (50.0) 96 52 (54.16)
Trop Anim Health Prod (2008) 40:311–315
(23.25%) reacted positively to T. gondii antigen; of these, 9 (90.0%) were in the titer range from 16–64, and 1 (10.0%) was in the range from 128-256. In Bafra, 13 (44.82%) sera out of 29 gave positive results. Of these 12 (92.30%) were in the range 16–64, and one (7.69%) in the range 128–256. The seropositivity in the 128-256 range were detected in a pregnant 17 year old woman. The prevalence of specific IgG antibodies gradually increased with age (Table 2). In those persons less than 20 years old the seropositivity was 16.0 % (four persons), which significantly differed from the 40.42% (nineteen persons) in those older than 20 years (P
