Studies on Tissue Responses in Primary and Subsequent Infections with Heterakis gallinae in Chickens and on the Process of Formation of Caecal Nodules

Abstract

1. In primary infections of chicks with 300 or 600 H. gallinae infective eggs, no clinical signs were apparent. Nodules were absent in all the experimental chicks as well as controls. Microscopically, few juveniles were observed in the caecal mucosa and the usual changes were mild congestion, few haemorrhages, and desquamation of superficial lining epithelial cells. Sections through a few thickened areas revealed a breached muscularis mucosa through which proliferated mucosal tissue had just invaginated into submucosa. The liver showed no changes.2. With primary infection of chicks with 300 or 600 infective H. gallinae eggs, and their subsequent infection after 25 days with 1,000 infective eggs, there were no clinical signs after either primary or secondary infections. Nodules of varying sizes were present on the caecal wall of infected birds only, their size and number varying with age of infection. Histopathologically, the types of nodules observed were, one associated with juveniles and the other with their absence; and nodules were present both in the invaginated mucosa and in the submucosa. It was confirmed that these caecal nodules were due to irritation by H. gallinae juveniles and their metabbolites, and that these nodules were more a reaction of already sensitised caeca to subsequent infections, a fact hitherto unreported. The liver showed nothing abnormal, and there was not much difference between the haematological values of experimental and control chicks.3. The actual process of formation of caecal nodules is demonstrated for the first time. The feasible explanation seems to be that on irritation of the already sensitised caeca by H. gallinae juveniles and their metabolites, hyperplasia of lymphoid tissue and epithelial cells results, which leads to a breach of the muscularis mucosa through which proliferated tissue of the mucosa invaginates. Later the muscularis mucosa constricts off and closes the nodule, the mucosa over it regenerates and becomes continuous. The present observations also indicate that the sterile nodular lesions usually found in natural infections may be the result of frequent infections, thus sensitising the chicks to subsequent infections.

Nodular typhlitis associated with the nematodes Heterakis gallinarum and Heterakis isolonche in pheasants: frequency and pathology with evidence of neoplasia

“…However, these authors did not refer to the occurrence of cecal nodules. Such nodules were noted by Khan et al (1994), in guinea fowls, Kaushik and Sharma Deorani (1969), Mutalib and Riddell (1982), Riddell and Gajadhar (1988) in domestic chickens, and Meads and Taylor (1963) in pheasants, microscopically classified as inflammatory (Meads & Taylor 1963, Kaushik & Sharma Deorani 1969 or granulomas (Mutalib & Riddell 1982, Riddell & Gajadhar 1988, Khan et al 1994, associated with the presence of H. gallinarum, as observed in this study. Helmboldt and Wyand (1972) reported the occurrence of neoplastic nodules in the golden pheasant, identified to leiomyomas caused by immature specimens of Heterakis sp., in despite of finding only H. gallinarum in the cecal lumen.…”

“…We agree with Riddell and Gajadhar (1988) in considering that the probable causes for the appearance of granulomatous nodules, that in our opinion could evolve to neoplasias, would be continuous reinfections with H. gallinarum provoking a tissular phase for the parasite as observed by Kaushik and Sharma Deorani (1969), mainly by infections with different strains of nematode harbored by other host species. These strains are likely not adapted to the ring-necked pheasant, and thus induce a higher pathogenicity, as shown in previous results.…”

“…The nematode Heterakis gallinarum (Schrank, 1788) can frequently be found in the caeca of pheasants (Madsen 1941, Gilbertson & Huggins 1964, Greiner 1972, Draycott et al 2000 and although considered of low pathogenicity in single infections (Lund & Chute 1974), previous studies report to a more severe pathology induced by this nematode in domestic Galliformes causing nodular typhlitis, with the formation of inflammatory or granulomatous cecal nodules (Meads & Taylor 1963, Kaushik & Sharma Deorani 1969, Riddel & Gajadhar 1988, Khan et al 1994). …”

ConcurrentCapillariaandHeterakisInfections in Zoo Rock Partridges,Alectoris graeca

“…The veterinary literature does not contain detailed parasitological and histological descriptions of Capillaria and Heterakis infections in rock partridges [2,[5][6][7][8]. Here, we describe parasitological and histological characteristics of concurrent Capillaria and Heterakis infections in rock partridges.…”

Pathobiology ofHeterakis gallinarummono-infection and co-infection withHistomonas meleagridisin layer chickens

“…Although many studies have investigated the prevalence of H. gallinarum in the chicken (Kurt & Acici, 2008;Mungube et al, 2008;Maurer et al, 2009) and the induction of pathological lesions after H. gallinarum infection (Kaushik & Deorani, 1969;Riddell & Gajadhar, 1988), no information is available on specific gut-associated immune reactions following the infection. A variety of studies in mammalian species demonstrated the importance of cell-mediated immune reactions in the clearance of nematode infection.…”