Studies on the Pathogenesis of Infectious Enterohepatitis (Blackhead) of Turkeys

Pathogenicity Studies on Trichomonas gallinarum in Domestic Poultry

“…Since pathogenesis was unproved in the present experiments as well as those of other investigators (Delappe, 1957;Harrison et al, 1954;Levine, 1961;Goedbloed and Bool, 1962;and Hinshaw, 1964) diagnosticians need to exercise caution in ascribing pathogenicity to T. gallinarum. None of the isolates could be considered economically detrimental on the basis of these experimental trials.…”

“…Becker, who reviews this subject in the latter text, is the author most frequently quoted. circumstantial evidence against trichomonads as possible pathogens appears to be increasing ..." Later work, in which DeVolt was a coauthor (Harrison et al, 1954), reported no lesions from trichomonads following experimental infections. Allen described (1941) elevated, cheesy, cream-colored hepatic lesions which she claimed could be differentiated from the depressed lesions caused by Histomonas meleagridis.…”

Establishing mono-eukaryotic Histomonas meleagridis cultures from in vivo infection contaminated with Tetratrichomonas gallinarum and Blastocystis spp.

“…Although they are regarded as apathogenic possibly due to subtype differences, contradictions remain about the pathogenic potential of Blastocystis spp. In addition, the amount of detected bacteria in liver samples of turkeys killed during the course of the disease was much lower than in birds which died from histomonosis (Harrison et al 1954). In addition, the amount of detected bacteria in liver samples of turkeys killed during the course of the disease was much lower than in birds which died from histomonosis (Harrison et al 1954).…”

“…Tetratrichomonas gallinarum (Delappe, 1957), and moulds e.g. This technique depends on precise microscopic recognition and selection of a single H. meleagridis parasite complicated by the morphological similarity to other host organisms such as T. gallinarum (Allen, 1936;Harrison et al 1954;Delappe, 1957) and Blastocystis spp. Further the coinfection of different protozoa in caeca, mainly T. gallinarum and Blastocystis spp., interferes and impedes the propagation of cultured H. meleagridis isolated from field outbreaks.…”

“…Candida albicans (Kemp and Reid, 1966b) as the etiological agent of blackhead disease had been made (Delappe, 1957). (Delappe, 1952;Harrison et al 1954) commonly present in caecal content of birds. In the past, many authors highlighted the necessity of cultural investigations.…”