Occurrence of <i>Eimeria</i> spp. and Intestinal Helminths in Free-Range Chickens from Northwest and Central Romania

Chickens raised in backyard free-range systems are confronted with a significant threat of parasitic infections. Among the parasitic agents, protozoa belonging to the genus <i>Eimeria</i> and helminths, including <i>Ascaridia galli</i>, <i>Capillaria</i> spp., <i>Heterakis gallinarum</i>, and <i>Strongyloides avium</i>, stand out as the most prevalent. The sampling protocol included sixteen localities in four counties within the Transylvania region of Romania. Fecal samples were collected from chickens reared in a backyard system. Fecal samples were screened for oocysts (O) and eggs (E) by flotation method, and their number per gram of feces (OPG/EPG) was calculated after counting them by McMaster method. Positive samples for <i>Eimeria</i> spp. were further analyzed by PCR (polymerase chain reaction) method to identify the <i>Eimeria</i> species. A total of 145 flocks were tested and the overall prevalence of infection was 53.1%. The most prevalent infections were with <i>A. galli/H. gallinarum</i> (25.5%), and <i>Eimeria</i> spp. (24.8%), followed by <i>Capillaria</i> spp. and strongyles. The mean OPG/EPG values were as follows: 63,577 for <i>Eimeria</i> spp., 157 for <i>Ascaridia/Heterakis</i>, 362 for <i>Capillaria</i> spp., and 1671 for <i>Strongyle</i> eggs. Identified <i>Eimeria</i> species were <i>E. acervulina</i> (41.7%), <i>E. tenella</i> (27.8%), <i>E. praecox</i> (16.7%), <i>E. brunetti</i> (16.7%), OTUy (operational taxonomic unit y) (8.3%), OTUz (operational taxonomic unit z) (8.3%) and <i>E. mitis</i> (5.6%). Intestinal parasites exhibit a high prevalence among chickens in backyard poultry flocks, and the presence of significant parasite burdens can adversely affect both productive and economic aspects. To the best of our knowledge, this is the first comprehensive study that aimed to analyze the prevalence of gastrointestinal parasites in chickens raised in a backyard free-range system in Romania, and the first report of OTUy species in Europe.