Dog echinococcosis in northern Spain: Comparison of coproantigen and serum antibody assays with coprological exam

Department of Immunology, Microbiology and Parasitology, Faculty of Pharmacy, University of the Basque Country, P.O. Box 450, 01080 Vitoria, Spain.
Veterinary Parasitology (Impact Factor: 2.46). 12/2006; 142(1-2):102-11. DOI: 10.1016/j.vetpar.2006.06.011
Source: PubMed


A large sheep-dog population from the province of Alava (northern Spain) has been investigated in order to determine the prevalence of the cestode parasite Echinococcus granulosus. Worms were detected in 14.0% of 721 dog faecal supernatants by coproantigen ELISA, and in 9.1% of 754 dog serum samples by serum antibody ELISA. A weak but statistically significant correlation (Spearman's rho=0.103, 95% CI: 0.023-0.178) between the two immunoassay results was found. In addition, eggs of the family Taeniidae were detected in 10.3% of 726 faecal samples examined by coproparasitological (flotation and sedimentation) tests. The overall E. granulosus infection rate, based on a Bayesian latent class model that accounts for the imperfect sensitivities and specificities of all diagnostic tests used, was estimated to be 8.0% (95% credible interval: 5.4-11.4%), corroborating that sheep-dog is the dog class most vulnerable to acquiring the infection. Dog sex did not influence the prevalence of E. granulosus, independently of the diagnostic test used or the dog region of origin. No significant linear correlation was found between the coproantigen ELISA OD values and the dog age (Spearman's rho=-0.049, 95% CI: -0.234 to 0.135), suggesting that there were no differences in prevalence of E. granulosus between old and young dogs. The obtained results highlight the importance of initiating a control program based on regular treatment of the sheep-dogs with praziquantel in the province of Alava.

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    • "Like Benito et al (2006) CpAg ELISA assays showed a very high negative predictive value, a characteristic that make them specially suited for the mass-screening of dog populations with low prevalence of E. granulosus. But, positive predictive values of CpAg ELISA techniques in Benito et al. (2006) study was relatively low which is in contrast with our results (Benito et al 2006). Parasite burden may effect on validity of the test. "

    Full-text · Article · Sep 2010
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    • "Cystic echinococcosis (CE) is an important problem for public health and the economy in many parts of the world. It is one of the most important zoonotic diseases and it is of great social importance (Benito et al., 2006; Daryani et al., 2007; Garippa et al., 2004). "
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    ABSTRACT: The variation in cystic echinococcosis (CE) prevalence and mean intensity was studied in relation to site, season and host age and sex. A total of 12,911 slaughtered animals, 140 camels, 2668 cattle, 6525 sheep and 3578 goats were inspected for hydatid cysts in Al Baha region, Saudi Arabia, in three study areas during four seasons from June 2008 to May 2009. The prevalence of infection was 32.85%, 8.28%, 12.61% and 6.56% in camels, cattle, sheep and goats respectively. The prevalence of the parasite varied significantly in relation to site, season and host age classes and sex in most host species. Spring showed the highest prevalence in camels, cattle and sheep. A significant association was found among host age classes and likelihood of infection in all examined hosts and the oldest age class was significantly more likely to be infected. The main effects in parasite intensity were host sex and age in most examined host species. A positive correlation was found between intensity of CE and host age class in all animal species examined. The most commonly infected organs were liver and lungs which constituted 48.75% and 32.83% respectively, of the total infected organs. There was a significant difference among host species in fertile cysts (P < 0.0001). The higher percentages of fertile cysts were in sheep (47.67%) and goats (23.99%) indicating that sheep and goats are the most important intermediate hosts for Echinococcus granulosus. Examined hydatid cysts of the liver had a higher fertility rate (38.79%) than those of the lungs (25.13%). Cysts size ranged from 1 to 8 cm in diameter. The mean cyst diameter was found in the lungs higher than that in the liver in all hosts. The range in the number of cysts was 1–33 in infected animals. The mean number of cysts was higher in lungs than that in liver in all examined animals. The viability rate of protoscoleces of liver fertile cysts (62.20%) was significantly higher than that of lung cysts (52.73%). In conclusion, these findings of infection, mean abundance and fertility rates of CE in slaughtered animals, prompt plans for further epidemiological studies and control programmes.
    Preview · Article · Jan 2010 · Acta tropica
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    • "Frequentist methods have traditionally been used for animal-health prevalence surveys. In recent years, however, applications of Bayesian analytic methods for veterinary epidemiologic data have increased (Cowling et al., 1999; Staubach et al., 2002; Clough et al., 2003; van Schaik et al., 2003; Borel et al., 2004; Branscum et al., 2004; Dorny et al., 2004; Geurden et al., 2004; Ngowi et al., 2004; Carabin et al., 2005; Durr et al., 2005; Benito et al., 2006; Rapsch et al., 2006; Wang et al., 2006). "
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    ABSTRACT: Although frequentist approaches to prevalence estimation are simple to apply, there are circumstances where it is difficult to satisfy assumptions of asymptotic normality and nonsensical point estimates (greater than 1 or less than 0) may result. This is particularly true when sample sizes are small, test prevalences are low and imperfect sensitivity and specificity of diagnostic tests need to be incorporated into calculations of true prevalence. Bayesian approaches offer several advantages including direct computation of range-respecting interval estimates (e.g. intervals between 0 and 1 for prevalence) without the requirement of transformations or large-sample approximations, direct probabilistic interpretation, and the flexibility to model in a straightforward manner the probability of zero prevalence. In this review, we present frequentist and Bayesian methods for animal- and herd-level true prevalence estimation based on individual and pooled samples. We provide statistical methods for detecting differences between population prevalence and frequentist methods for sample size and power calculations. All examples are motivated using Mycobacterium avium subspecies paratuberculosis infection and we provide WinBUGS code for all examples of Bayesian estimation.
    Full-text · Article · Jul 2008 · Animal Health Research Reviews
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