The European eel (Anguilla anguilla) is a critically endangered species. Red anus syndrome (RAS) is known to be associated with parasitic infections of the eel, particularly with Anguillicola crassus, but the full range of causative pathogenic organisms has not been systematically investigated. Here we examined the infective organisms and histopathological and ultrastructural features of seventy eels with RAS. In total, nine different pathogens were detected in association with RAS: Pseudomonas aeruginosa were present in twelve specimens (17%), the metacercaria of Euclinostromum heterostomum in three cases (4%), Gastrostome (Bucephalidae family) in seven cases (10%), A. crassus in forty-five cases (64%), Bothriocephalus in seventeen cases (24%), and Proteocephalus in twenty-three cases (32%). Yeast, amoeba, and myxobolus-like pathogens were seen in the anal skin in all cases when examined in combination with electron microscopy. Histopathologically, the lesions appeared as anoproctitis of varying severity from mild anusitis to severe haemorrhagic anoproctitis, with severe perianal oedema, haemorrhage, and proctoptosis. Gut inflammation ranged from mild catarrhal enteritis to severe haemorrhagic enteritis with mucosal sloughing. RAS is associated with a range of parasitic infections, not only A. crassus, some of which we describe here for the first time. Since RAS is not associated with direct invasion by parasites, it is likely that RAS is a secondary phenomenon caused by superadded infection on a background of generalised immunosuppression, or indirect local toxic effects. RAS may be used as a non-invasive indicator of underlying parasitic infection, but further investigations are required to establish the causative organisms for effective fishery management.
The Great Blue Turaco (Corythaeola cristata) has been raised in captivity for over a hundred years, but their susceptibility to infectious disease is very poorly documented. The macroscopic, histopathologic, and ultrastructural changes in the respiratory tract of nine Great Blue Turacos (Corythaeola cristata) who died in captivity were investigated. Macroscopically diffuse granulomatous lesions were observed in the lung and the associated air sacs, with a grey-greenish mold on their inner surface. Histopathologic examination revealed widespread necrosis in the lungs associated with vasculitis. Microthrombi were observed in the blood vessels suggesting disseminating intravascular coagulation. Intra-alveolar hemorrhage and infiltration with macrophages, plasma cells, epithelioid cells, and multinucleate giant cells were observed. PAS staining showed hyphae and conidia, While, Ziehl-Neelsen stain was negative. Transmission electron microcopy examination revealed the presence of Aspergillus fumigatus conidia invading the pulmonary tissue as semilunar spores within the alveolar macrophages. Lysosomal degranulation was also observed in association with fragmented spores suggesting active phagocyosis. Awareness of this condition might improve the rapid and appropriate treatment of exotic birds kept in captivity.
Three dead tigers were dissected and representative samples from the gastric mucosa, duodenum and livers were taken for histopathology and transmission electron microscope for further investigation of the cause of death. Post-mortum examination showed accumulation of straw in the stomach outlet (Phytobezoar), together with pronounced ulcers, which was surrounded by hemorrhagic zones. Light microscopy showed loss of the gastric mucosal epithelium, necrosis of the gastric glands, hyperemia of the submucosal blood vessels, and lymphocytic and few neutrophils in the submucosa. These changes indicated acute-subacute gastritis. Subcapsular hepatocellular necrosis expressed by hepatocellular lysis, pyknosis and karyorhexis of the hepatocytes nuclei were also observed. Transmission electron microscopical observations showed the presence of intercellular, and interacellular elongated, coiled, and spiral form of Hellicobacter bacteria in close contact with the gastric glandular epithelium. Moreover, rounded-shaped bacteria were observed in association with the helicobacter bacteria. The duodenum revealed also the presence of both types of bacteria. These results suggest mixed infection with the complication of Phytobezoar which cause obliteration of the stomach outlet with chronic constipation and fever, might be responsible for the death of tiger.
A field study of outdoor cultivated habitats was conducted in the northern part of the Western Desert in Egypt (Al DabaaMarsa Matroh Governorate) between March 2010 and August 2013. Samples were collected from skin lesions occurring on the Egyptian lesser blind mole rat (Spalax leucodon Egyptiacus). Gross examination of the lesions showed alopecia and grey, circumscribed nodules, average size 2-5mm, in the hair-free thigh regions of the animals, varying from three to ten in number. Skin scrapings revealed numerous Lynxacarus egyptiacus, as well as other ectoparasites including Polyplax serrata and gamasid mites. Histopathological examination of the skin lesions showed features of demodetic perifollicular inflammation with aggregations of eggs in the dermis and in the keratin layer. Destroyed hair follicles were associated with fibroblastic proliferation and lymphocytic infiltration. Invasion with Polyplax serrata and gamasid mites resulted in keratinolysis, itching, and slight haemorrhage.This study is the first study to report on mixed lice infestations, and their associated histopathological changes, occurring in the Egyptian lesser blind mole rat. Since the population of this species is in decline, data relating to pathologies that occur in the Egyptian mole rat are of significance.
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