Seroepidemiological survey of Rhodococcus equi infection in asymptomatic horses and donkeys from southeast Turkey

Abstract

n order to assess the level of Rhodococcus equi infection in southeast Turkey, 679 sera from healthy foals and adult horses and 78 sera from donkeys were tested by indirect ELISA using a R. equi reference strain (ATCC 33701) as antigen. Eighty (11.7 %) sera from horses and 9 (11.5 %) sera from donkeys with titres >0.85 were positive. The prevalence of seropositive horses in Sanliurfa Province was higher than in Diyarbakir Province; 56 (13.9 %) horses in Sanliurfa Province and 24 (8.7 %) horses in Diyarbakir Province were defined as seropositive. In Sanliurfa Province 14.5 % of female (n = 343) and 10.1 % of male (n = 59) horses tested were defined as seropositive, while in Diyarbakir Province more males (11.4 %, n = 114) were seropositive than females (6.7 %, n = 163). Horses 1 to 5 years of age were found to have the highest seropositivity rate in both provinces. A total of 78 sera from donkeys were investigated in Sanliurfa Province, of which 9 (11.5 %) were positive by ELISA. Among the 9 positive sera, 6 (12.8 %) were from donkeys 1-5 years old and 3 (13.6 %) were from donkeys >5years of age. Nopositive sera were found in donkeys less than 1 year old. Five(12.5 %) sera of females and 4(10.5 %) sera of males tested were positive. These results indicate the existence of R. equi in the horse populations in Sanliurfa and Diyarbakir Provinces. Similar infection rates were found for donkeys in Sanliurfa. This suggests the importance of serological surveys to diagnose R. equi infection in the region and to prevent the zoonotic risk

Ruminant Brusellozisinin Endemik ve Yaygın Olduğu Kars ve Ardahan Yörelerinde Atlarda Brusellozisin Seroprevalansı

“…Solmaz et al 10 reported a seroprevalance of 60.59% (123/203) in horses raised in Van province of East Turkey by RBPT and out of these 123 positive serum samples 98 (79.67%) showed 1/40 or higher titers by SAT. The result of another study on horse brucellosis in Southeast Turkey was 13.68 and 0.51% by RBPT and SAT, respectively 11 . If we take a look at the situation in neighbouring countries; in a study conducted in North-East of Iran, the seroprevalence of brucellosis was determined as 2.5% in horses by RBPT and SAT 12 .…”

Seroprevalence of <i>Rhodococcus equi</i> in horses in Israel

“…The cut-off value for positive samples was set as the mean OD of the negative control plus 3 standard deviations (s.d. ), which corresponded with 20% seropositivity (Tel et al 2011 ).…”

“…Serum samples were collected from apparently healthy horses at selected farms that represent the geographic distribution of the equine population in Israel. Because R. equi prevalence in Israel has never been evaluated, sample size was calculated using the estimation that the Israeli equine population consists of approximately 30 000–40 000 horses, and the prevalence that was found in a similar survey from Turkey was about 10% seropositivity in subclinically infected horses (Tel et al 2011 ). With these data, the required sample size for prevalence of 10% ± 5% was 219 horses (Win Pepi 11.43).…”

“…The strain used for the preparation of the antigen has been previously shown to include VapA protein (Tel et al 2011 ); the solid-phase antigen used also included a surface-exposed protein-encoded VapA gene. In this assay, antigen did not comprise solely of VapA protein, since increasing the specificity of the antigen will lead to a decrease in the sensitivity of the assay.…”

“…Several studies in recent years attempted to evaluate and improve the sensitivity and specificity of ELISA screening, and to determine the cut-off values for early detection of clinical cases (Giguère et al 2003 ; Martens et al 2002 ; Sanz et al 2014; Witkowski et al 2012 ). Despite these limitations, serological surveys may be of value in identifying endemic farms and assessing the potential for clinical infection in susceptible animals (Attili et al 2006 ; Sanada, Noda & Nagahata 1992 ; Tel, Arserim & Keskin 2011 ). A serological survey of subclinically infected horses in Japan demonstrated that R. equi seroprevalence in farms may differ between clinically endemic, sporadic and ‘clean’ farms (Sanada et al 1992 ).…”