Search by key word or author


  Contributed Papers: Posters
Diagnosis and Epidemiology

 

Identification of Coccidia Species in Broiler Chickens in Argentina

Hernán González1, Mauricio De Franceschi2 and Hebe Barrios1
1Departament of Basic Science, 2Departament of Technology. Luján National University. Ruta Nacional 5 y Avenida Constitución. 6700. Luján. Argentina. sip@mail.unlu.edu.ar.


We need not to assert that coccidiosis is highly prevalent in poultry production. Therefore, it is important to determine the presence and the frequency of the species present in any region. The identification of species depends on the ability to use traditional diagnostic methods. The development of molecular techniques in different studies requires simple techniques for DNA extraction. The identification of coccidia in broiler chickens in the provinces of Buenos Aires and Entre Rios was made using conventional methods, and the presence of Eimeria sp. was confirmed using molecular biology. In both provinces, 63 samples of 74 farms were positive for presence of coccidia, whereas the remaining 11 were negative. All seven species were present in variable percentages. Characteristic lesions of Eimeria acervulina and ovoid oocysts were present in all 59 positive samples (93.65%). Typical ovoid oocysts of Eimeria maxima and typical lesions in the jejunum-ileum were present in 34 samples (53.97%). Eimeria mitis was present in 24 farms (38.10%), where it produced typical sub spherical oocysts before 93 hours post-inoculation. Eimeria tenella was confirmed in 15 samples based on oocyst size and typical lesions in the cecum (hemorrhages, coagulated blood in the lumen, and thickened cecal mucosa). Eimeria praecox was conclusively identified in 14 samples (22.22%) by the typical oocysts present in the feces 84 hours post-inoculation. Lesions in the lower small intestine of 5 samples (7.94%) were typical of Eimeria brunetti, and Eimeria necatrix was present in 5 farms (7,94%). Finally, the high prevalence of Eimeria acervulina and Eimeria maxima was related to the high incidence of mild clinical and subclinical cases. The conventional methods are not adequate for a definitive identification for the differentiation between Eimeria acervulina and Eimeria mitis. The low incidence of Eimeria praecox, Eimeria brunetti, and Eimeria necatrix warrants the reconsideration of the inclusion of these species in the specific immunogen for broiler vaccination. The presence of Eimeria DNA, generated by the amplification of regions ITS1 using primers EF1 and ER1, and ITS2 with primers WW2 and WW4r developed in the University of Melbourne, confirm the presence of these species in our country. It is concluded that the methodology used may be the starting point for the identification of specific primers aiming at the development of vaccines based on native strains.

back  |  print