Changes in the ultrastructure of the caecum of chickens caused byTrichomonas gallinarum

Abstract

The ultrastructure of the normal caecum of chickens and of chickens infected withTrichomonas gallinarumhas been investigated. In infected caeca some villi and crypts of LieberkÜhn appear normal whereas others show marked changes in structure of the epithelial cells. The most obvious changes are loss of microvilli and glycocalyx and an increase in number of vesicles which stain metachromatically with Azur II.T. gallinarumhas been detected between epithelial cells and in the lamina propria. Bacteria often, but not always, accompanied the protozoa in the tissues.

Trichomonads in birds – a review

“…Very often those samples are contaminated with bacteria or other protozoan parasites, mainly H. meleagridis. The pathogenic potential of T. gallinarum was demonstrated by Lee (1972) following cloacal infection of 3-6-week-old chickens with the caecal content of naturally infected broilers harbouring T. gallinarum. Allen (1941) reported T. gallinarum-induced lesions in the caecum and liver of domestic fowls and turkeys and that the parasite may be a possible causative agent of enterohepatitis.…”

“…Tetratrichomonas gallinarum frequently occurs in mixed infections with other protozoa, especially Histomonas meleagridis and Blastocystis spp., due to its presence in the large intestine (Tyzzer, 1920). Various studies investigated the pathogenicity of T. gallinarum either in naturally infected chickens and turkeys or via experimental infection, with contradicting outcomes (Allen, 1941; Goedbloed and Bool, 1962; Kemp and Reid, 1965; Lee, 1972; Patton and Patton, 1996; Norton, 1997; Richter et al 2010; Amin et al 2011). However, it needs to be mentioned that these investigations could have been significantly influenced by some other concurrent infections due to limited characterization of samples obtained from naturally infected birds.…”

“…This suggestion disagreed with the findings of Tyzzer (1920Tyzzer ( , 1934, who already proved that H. meleagridis was the true aetiologic agent of such an infection. The pathogenic potential of T. gallinarum was demonstrated by Lee (1972) following cloacal infection of 3-6-week-old chickens with the caecal content of naturally infected broilers harbouring T. gallinarum. Although the infected chickens appeared healthy, a loss of microvilli and reduction of glycocalyx with complete loss of the polysaccharide matrix was noticed.…”

First report of typhlitis/typhlohepatitis caused byTetratrichomonas gallinarumin three duck species

“…Furthermore, T. gallinarum has been found to be associated with clinically relevant infections in various bird species, including manifestations at extraintestinal sites (Patton et al , 1996; Crespo et al , 2001). There have been repeated attempts to clarify the pathogenicity of T. gallinarum with the help of experimental infections, mostly in turkeys and chickens, with various outcomes and inconsistent pathological lesions (Allen, 1941; Kemp & Reid, 1965; Lee, 1972; Kulda, 1974; Norton, 1997).…”

Antiprotozoal activities determined in vitro and in vivo of certain plant extracts against Histomonas meleagridis, Tetratrichomonas gallinarum and Blastocystis sp.

“…blackhead disease, histomonosis, infectious enterohepatitis) (Tyzzer 1920) in poultry, a disease of economic importance in turkeys and chickens characterized by severe enterohepatitis. Coinfections with Tetratrichomonas gallinarum (Lee 1972) and Blastocystis spp. (Lee 1970;Stenzel and Boreham 1996), two other widespread protozoa in poultry, can be observed quite often in birds infected with H. meleagridis although the clinical relevance of these parasites in poultry is discussed controversially (Allen 1941;Kemp and Reid 1964;Lee 1970;Lee 1972;Stenzel and Boreham 1996;Norton 1997).…”