Immunohistochemistry for the diagnosis of aspergillosis in Turkey poults

Abstract

SUMMARYFrom each of two flocks (A and B) of poults comprising 14,100 females and 11,300 males, respectively, 15 poults were examined pathologically. Poults of flock A had signs of neurological disturbances whereas birds from flock B showed respiratory symptoms. Gross lesions were observed only in two poults from flock A in which minute circular areas of cerebral malaria were seen. Histopathologically, the brain lesions contained fungal elements, and so did some of the pulmonary granulomas detected in three and six poults out of four and six birds examined from flock A and B, respectively. Mycological cultivation was attempted from the brains and lungs of five poults from flock A. However, only from the brain of a single bird a fungus, identified as Aspergillus fumigatus, was grown. Immunohistochemistry was applied because the histomorphology of fungal elements within some lesions did not offer any characteristics allowing an assessment of the identity of the infective fungi. Moreover, as fungi could not be detected within all lesions, immunohistochemistry accomplished the screening of tissues. For immunostaining of tissues a panel of monoclonal and polyclonal antibodies identifying agents of aspergillosis, candidosis, fusariosis, scedosporiosis, and zygomycosis, was used. Due to a strong and uniform reactivity of all fungal elements with immunoreagents to Aspergillus spp. an unequivocal diagnosis of aspergillosis was established in all mycotic lesions. Apart from the establishment of an aetiological diagnosis, the application of immunohistochemistry also disclosed fungal fragments in granulomas which could not be identified with conventional histochemical stains.

Immunohistochemical detection of fungal elements in the tissues of goslings with pulmonary and systemic aspergillosis

“…Thus, the presumptive diagnosis of invasive fungal infections based on histologic examination ideally should be confirmed by immunological techniques using monoclonal antibodies (Piérard et al, 1991;Buckley et al, 1992;Jensen et al, 1993;Jensen et al, 1996a;Fenelon et al, 1999). Similarly, in this study, within the granulomas in both the lungs and abdominal viscera significantly more fungal elements were disclosed when immunostaining with monoclonal antibody was used compared to the conventional fungus staining methods, consistent with the observations of Jensen et al (1997) in turkeys. In the lesions in the above-mentioned sites fungal hyphae, spores, and also conidiophores, which were especially observed when the granulomas were opened to the airways, reacted strongly with immunostaining using monoclonal antibody.…”

“…In the cases with systemic aspergillosis, infection of the serosal linings was found to extend into the underlying liver, spleen and kidney parenchyma. As in other birds (Hawkey et al, 1984;Erer et al, 1986;Bowes, 1990;Jensen et al, 1997), the granulomas contained central necrosis surrounded by heterophils, macrophages, and particularly in late granulomas, multinucleated foreign-body giant cells and a scant amount of outer fibrous capsule. It is probable that the extension of serosal infection to the above-mentioned organs was due to the persistence of the infection, as stated by Okoye and Okeke (1986), who reported similar changes in the liver, kidney, spleen and bursa of Fabricius of chickens infected with A. flavus.…”

“…As stated by some authors (Piérard et al, 1991;Kaufman, 1992;Buckley et al, 1992;Jensen et al, 1993;Jensen et al, 1997), when dealing with filamentous fungal infections, except for mycelia of Mucor spp., the differentiation of hyphal forms of Aspergillus spp. from Fusarium spp.…”

“…Furthermore, some inflammatory reactions may suggest the possibility of a mycotic infection, even though no fungus is identified in tissue sections (Jensen, 1994;Jensen et al, 1996a). For these reasons, immunohistochemical techniques are increasingly used for obtaining specific diagnosis in cases of mycosis in birds (Carrasco et al, 1993;Jensen et al, 1997) as well as in mammals. Moreover, immunohistochemical methods are also highly suitable for the screening of tissues for fungal elements, and this is particularly true when only a few fragments of fungi are present Jensen, 1994;Carrasco et al, 1998).…”

Aspergillusinfections in birds: a review

“…Neurological signs can be caused by Aspergillus spp. (Jensen et al, 1997). Epidermal cysts associated with A. fumigatus have been described in the comb of a silky bantam chicken (Suedmeyer et al, 2002).…”