Low-Dose Immunization of Northern Bobwhites (Colinus virginianus) with Eimeria lettyae Provides Protection Against a High-Dose Challenge

Efficacy of immunization compared to an anticoccidial drug combination in the management of challenged coccidiosis in Japanese quail

This study was carried out to compare the efficacy of immunization, by a low-dose of live sporulated oocysts of different Eimeria species separately, with the efficacy of amprolium plus sulphaquinoxaline in the management of challenged coccidiosis in Japanese quail. Dropping samples were collected and sent to the laboratory for isolation and identification of Eimeria species. Three Eimeria species were isolated and identified as E. bateri, E. uzura, and E. tsunodai. Single oocyst isolation and propagation were done successfully for each species. For the experimental trial, Japanese quails were divided into 11 groups of thirty birds each and given different treatments. The assessment of each treatment relied on clinical signs, mortality, lesion score, oocyst output, weight gain, feed conversion ratio, and hematological parameters. The results revealed that immunization, with any isolated species, gave the best results regarding all tested parameters. Thus, we concluded that immunization by a low-dose of live sporulated oocysts was better compared to amprolium plus sulphaquinoxaline in the management of coccidiosis in Japanese quail.

Gene expression in rabbit appendices infected with Eimeria coecicola

Eimeria coecicola causes intestinal coccidiosis in rabbits and, thereby, enormous economic losses in rabbit farms. Here, we investigate the final target site of E. coecicola, the appendix of rabbits, at the level of gene expression. Rabbits, orally infected with E. coecicola, begin to shed parasitic oocysts with their feces on day 5 p.i., and approximately 1.1 million oocysts are maximally shedded on day 7 p.i. At maximal shedding, the appendix has increased in size by about 2-3-folds and reveals increased hemorrhage which is associated with increases in nitrite/nitrate, malondialdehyde and catalase activity and a decrease in glutathione. Agilent 2-color oligo whole rabbit genome microarray, in combination with quantitative real-time PCR, detects 45 and 36 genes whose expression is more than 2-fold up- and down-regulated, respectively, by E. coecicola infection on day 7 p.i. The most dramatic increase by approximately 50-fold reveals the mRNA of the pro- and anti-inflammatory pleiotropic cytokine interleukin 6 (IL-6), whereas the largest decrease by approximately 13-fold is detected for mRNAs encoding for DBP, SULT3A1, CRP and glutathione-S transferase. Also, there are up- and down-regulations in the expression of genes encoding diverse regions of antibodies. Our data suggest that IL-6 plays a central role in the infection of the appendix of rabbits by E. coecicola, presumably involved in both pathological injuries, host defences and healing processes.

Construction of PCR primers to detect and distinguish Eimeria spp. in northern bobwhites and a survey of Eimeria on gamebird farms in the United States

Coccidiosis is an important disease in captive gamebirds, including northern bobwhites (Colinusvirginianus). Three Eimeria species, Eimeria lettyae, Eimeria dispersa, and Eimeria colini, have been described in bobwhites. Distinguishing the various Eimeria spp. is often problematic because of similarity in oocyst morphology and site of infection and thus requires live bird infections to distinguish between the coccidian species. To aid in identification and diagnosis, PCR specific primers were generated against the internal transcribed spacer region 1 (ITS-1) of the ribosomal RNA gene using sequences obtained from coccidian-positive samples collected from diagnostic cases or litter from captive bobwhites. Three distinct Eimeria spp. were detected. Species-specific primers were constructed and used to survey the prevalence of the species in 31 samples collected from 13 states. The primers survey results identified E. lettyae, E. dispersa, and Eimeria sp. in 20 (64.5%), 22 (71%), and 29 (93.5%) of the samples, respectively. Mixed infections were common: 13 (41.9%) samples had 3 Eimeria spp., 14 (45.2%) had 2 spp., and 4 (12.9%) samples had only 1 species. The species were widely distributed over the area sampled and were not associated with the age of the flock.