Dynamic Distribution Of Histomonas Meleagridis In Turkeys

Histomonas meleagridis, a flagellated protozoan parasite, is the causative agent of histomonosis in turkeys, laying hen and chicks. Heterakis gallinarum is an important main spread medium of Histomonas meleagridis, because of it's eggs can protect Histomonas meleagridis well. This artical is based on separate Heterakis gallinarum and it's eggs in order to determine the dissemination of Hislomonas meleagridis in Heterakis gallinarum and the mechanisms of Heterakis gallinarum to spread Histomonas meleagridis.Then following an oral infection of turkeys with embryonated eggs of Heterakis gallinarum which contain Histomonas meleagridis, in order to detect the dynamic distribution of Histomonas meleagridis in turkeys samples by PCR.At the same time, observed the pathological changes in various organs and tissues of turkeys' post- infection, in order to study the relationship between Histomonas meleagridis and pathological changes.The first part of this study was based on the separation of Heterakis gallinarum and it's eggs in order to determine the dissemination of Histomonas meleagridis in Heterakis gallinarum.The DNA of Histomonas meleagridis could be detected in male Heterakis gallinarum(45%), female Heterakis gallinarum with eggs(50%), unembryonated eggs Heterakis gallinarum (65%)and embryonated eggs of Heterakis gallinarum(65%)by PCR. However, The DNA of the parasite could not be detected in the female Heterakis gallinarum which is without eggs. Then following an oral infection of turkeys with the materials above mentioned,the results indecated only the male Heterakis gallinarum and the embryonated eggs of Heterakis gallinarum can cause histomonosis.The second part of the study was following an oral infection of turkeys with embryonated eggs of Heterakis gallinarum which contain Histomonas meleagridis, in order to detect the dynamic distribution of Histomonas meleagridis in turkeys samples by PCR.The results showed that Histomonas meleagridis was first detect in caeca at day 6,but until day 8 the positive rate of cecal gradually increased; Then at day 7 Histomonas meleagridis was detect in liver (lesion-free area), until day 15 the positive rate of Histomonas meleagridis was gradually increased; The macroscopic lesions of liver was appeared at day 8,from then on, Histomonas meleagridis was detected in most liver (lesional area); At day 9 Histomonas meleagridis was detected in the bursa of fabricius, however,the positive rate of Histomonas meleagridis was not increased day by day;After day 13, Histomonas meleagridis was detected in the brain, lung, heart, kidney, and the spleen of the turkeys. However, Histomonas meleagridis was not detected in the cecal content, rectum, jejuno-ileum,duodenum, pancreas, muscle of the thigh and blood.The third part of the study was take turkeys'caeca, rectum, jejuno-ileum,duodenum, proventriculus, liver (lesion-free area), liver (lesional area), spleen, pancreas, bursa of fabricius, kidney, heart, lung, brain and muscle of the thigh with HE staining. The results showed that only in the characteristic lesions of Histomonas meleagridis was only in the caeca, liver (lesion-free area), liver (lesional area) and spleen. The pathological changes of other tissues and organs were in different level.