Identification of a Short DNA Bar Code in the 18S rDNA for Improved Differentiation of Common Eimeria Species Infecting Chickens.

The coccidian species Eimeria is a parasitic protozoan that causes the gastrointestinal disease coccidiosis in numerous vertebrate species. Incidence of the disease in commercial chickens produces drastic economic losses. Traditionally, detection of Eimeria has been performed using classical methods such as observation of oocyst morphology. However, molecular methods to detect and speciate Eimeria are becoming more prevalent. The 18S ribosomal gene, in particular, has been a widely used DNA amplification target for detection of Eimeria. Although the full-length gene is typically used for this purpose, newer research targeting shorter regions of the gene is being performed. This study investigated the suitability of a 120-base pair (bp) DNA bar code within the 18S gene for species differentiation. When comparing sequence variation from the Eimeria species infecting chickens, shortening the 18S gene to the 120-bp highly variable region provided increased species differentiation, while also reducing intraspecies variation. This DNA bar code is useful for distinction of the Eimeria species infecting chickens and should be considered for future molecular detection assays and metagenomic sequencing.

Genomic analysis of Eimeria spp. populations in relation to performance levels of broiler chicken farms in Arkansas and North Carolina.

The impact of coccidiosis outbreaks on the productivity of broiler chicken farms can be substantial, depending on the severity of disease caused by particular species and strains of Eimeria. We examined the genetic diversity of Eimeria species present in commercial broiler farms in relation to their performance level. Four groups of broiler chicken farms in Arkansas (AR) and North Carolina (NC), having either high or low performance levels, were sampled for Eimeria spp. oocysts. We amplified gDNA from oocysts by using genus-specific primers targeting 18S ribosomal RNA, the first and second internal transcribed spacer regions, and cytochrome c oxidase subunit I as the established species-specific primers. Eimeria spp. diversity was not homogenous among the 4 farm groups, with less-pathogenic species (E. mitis and E. mivati-like) associated with AR and NC high-performance farms, respectively, and a pathogenic species (E. brunetti) associated with AR low-performance farms. Sequence analyses identified multiple E. maxima and E. mitis genetic variants, from which 2 E. maxima variants were unique to low-performance farms. Distinct populations of sequences at the NC high-performance farms were identified as E. mivati-like, based on homology searches. Our study demonstrated the utility of analyzing multiple genomic loci to assess composition and polymorphisms of Eimeria spp. populations.

[The influence of coccidiostats on the course of coccidiosis and production results in an industrial rabbit farm]. / Wplyw kokcydiostatyków na przebieg kokcydiozy i efekty produkcyjne w przemyslowej fermie królików.

The study was carried out on material consisting of 3375 rabbits of the White New Zealand breed. The total number of 9 species of coccidia were found, 8 of which were intestinal (E. perforans, E. media, E. magna, E. irresidua, E. coecicola, E. flavescens, E. piriformis oraz E. intestinalis) and E. stiedai inhabiting the liver. Three specirs - E . irresidua, E. coecicola and E. flavescens have been found in Poiand for the first time. Three of four coccidiostats examined i.e. Sacox, Cycostat and Baycox may be used to prevent coccidiosis in rabbit farm. Activity of Vetrocox is less effective and it should not be used in the prevention of coccidia infection. At the age of 90 days the best results were obtained by treatment of Sacox (257 g of increase body weight and 9 per cent lower mortality comparing with the control group), the second test result was after two doses of Baycox and after Cycostat treatment.

Identification of economically important parasites.

The taxonomy of a parasite can be an important guide to its pathogenic characteristics. A wide range of anatomical, biochemical and behavioural tests is now being developed to define different strains and subspecies of the main tropical parasites.