Histological patterns of the intestinal attachment of Corynosoma australe (Acanthocephala: Polymorphidae) in Arctocephalus australis (Mammalia: Pinnipedia)

Abstract

The mucosal attachment pattern of Corynosoma australe in the intestines of Arctocephalus australis is described. Normal and abnormal tissue were sampled from 32 hosts to be submitted to histological routine protocol to embedding in paraffin and permanent mounting in balsam. Corynosoma australe shows three different degrees of body depth intestinal attachment (BDINA-1-3). BDINA-1: it is exclusive of the small intestine and the parasite attaches on the villi; BDINA-2: parasite affects the Lieberkühn crypts in several depth levels and, BDINA-3: the parasite reaches the submucosa. These attachment patterns alter the mucosa by degeneration and dysfunction due to necrosis of mucosal structure, great quantities of cellular debris and significant reduction of the mucosal thickness. Other aspects are crater-like concave holes (CLCHs) as sites where C. australe could be attached-detached several times according to adult migratory processes within luminal intestine space. The submucosa shows edema probably due to the local mucosal alterations resulting in homeostatic break. There is no severe inflammatory response by host but BDINA-1 to BDINA-3 and CLCH could represent foci to secondary opportunistic infections and significant areas of malabsorption in severally infected hosts contributing to increase clinical signs of preexistent pathologies.

Morphology, performance and attachment function in Corynosoma spp. (Acanthocephala)

“…Likewise, in fully attached individuals of Corynosoma spp. there are observations of worms with the proboscis fully [ 15 ] or partially [ 16 ] everted. It is therefore possible that the relatively long proboscis typical of Corynosoma spp.…”

“…9 b). Moreover, the host’s tissue is so strongly pulled upwards by the DNRs that a crater is frequently formed during deep attachment [ 2 , 16 ]. This elevation of the substratum often traps host tissue between the hooks of the proboscis and the spines on the opposite disk wall, “...as though staples had been applied” on it [ 2 ] (Fig.…”

“…If such a process is combined with contraction of circular muscles in the hindtrunk, and relaxation in the foretrunk, the net effect should also be an expansion of the disk border. In deeply attached worms, this expansion would produce a ‘wedge’ effect against the gut wall because the disk is literally buried in the mucosa ([ 16 ]; F.J. Aznar, unpublished observations). Not surprisingly, disk spines are larger on the border than anywhere else on the disk [ 17 ].…”

Temporal and Geographical Variation of Intestinal Ulcers in Grey Seals (Halichoerus grypus) and Environmental Contaminants in Baltic Biota during Four Decades

“…In the present study, the observed histological responses to the intestinal parasites mainly comprised a thin or absent mucosa and mild infiltration of lymphocytic cells and eosinophils close to the attachment sites of the parasites. Other studies have found only a slight intestinal inflammatory response to Corynosoma in seals and the attachment pattern of Corynosoma observed in South American fur seals significantly reduced the thickness of the intestinal mucosa [39,40]. Minor intestinal lesions (erosions less than 10 mm in diameter) in Baltic grey seals are supposedly unavoidable due to the attachment of the parasites, although larger ulcerations are likely to be pathological.…”

Gastrointestinal helminths of waterfowl (Anatidae: Anatinae) in the Lerma marshes of central Mexico: Some pathological aspects

“…This variety of responses could be attributed to several causes: 1) the time that the parasites had been affecting the host, since heterophiles are the first line of attack against the parasite; 2) the extent of the lesion associated with the size of the entire parasite or fixation structures; 3) type of fixation structures, 4) group of parasite or 5) by bacteria or fungi inoculated in the cuticle during the process of fixation to the organ ( Dunstand et al, 2019 ), which stimulate the appearance of heterophiles ( Phillips et al, 1980 ). According to the classification of the lesions established by Silva et al (2014) , who studied the damage caused by the acanthocephalan Corynosoma australe in mammals, P. constrictum and Filicollis sp., the 2 species found in the waterfowl, could be located in the grade II, due to the presence of necrosis, destruction of villi and Lieberkühn crypts and by the low lymphocyte infiltration; the only differences with respect to the study by Silva et al (2014) , is the presence of heterophils and giant cells in our samples. This type of reaction suggests that the 2 species had been attached to the intestine for a long time, so the host's immune system developed this response, preventing the worms from causing more damage, or that the helminths stimulated the proliferation of fibroblasts around them to evade the immune system.…”