Sequential pathological studies in goats infected intratracheally with Aspergillus fumigatus

Conidiobolomycosis, cryptococcosis, and aspergillosis in sheep and goats: a review

We review herein infections by Conidiobolus spp., Cryptococcus spp., and Aspergillus spp. in sheep and goats. Conidiobolus spp. are common causes of rhinitis in sheep and are less frequent in goats, in which Conidiobolus spp. also cause skin lesions. Cryptococcus spp. cause rhinitis, meningitis, encephalitis, and pneumonia in goats, and are rarely observed in sheep. Aspergillus spp. may cause rhinitis in goats, and pneumonia and mastitis in sheep and goats. Gross and microscopic lesions caused by these 3 fungal infections may be similar to each other. The diagnosis of these diseases must be based on gross and microscopic lesions, coupled with detection of the agent by immunohistochemical, molecular, and/or culture-based methods.

Nasal and cutaneous aspergillosis in a goat

Nasal and cutaneous aspergillosis is reported in an adult goat. The clinical signs were severe respiratory distress due to partial nasal obstruction, bilateral mucopurulent nasal discharge, skin nodules on the ears and dorsal nasal region and focal depigmentation of the ventral commissure of the right nostril. At necropsy examination, sagittal sectioning of the head revealed a yellow irregular mass extending from the nasal vestibule to the frontal portion of the nasal cavity. Microscopically, there was pyogranulomatous rhinitis and dermatitis, with numerous intralesional periodic acid-Schiff-positive fungal hyphae morphologically suggestive of Aspergillus spp. Aspergillus niger was isolated by microbiological examination.

Virulence of fungal spores determined by tracheal inoculation of goats following inhalation of aerosolized sterile feedyard dust

OBJECTIVE

To compare the virulence of spores of 7 fungi by tracheal inoculation of goats following exposure of goats to an aerosol of sterilized feedyard dust. Animals-54 weanling Boer-Spanish goats.

PROCEDURE

A prospective randomized controlled study was conducted. There were 7 fungal treatment groups, a tent control group, and a pen control group (n = 6 goats/group). Goats in the 7 treatment and tent control groups were exposed to autoclaved aerosolized feedyard dust for 4 hours in a specially constructed tent. Goats in the 7 treatment groups were then inoculated intratracheally with 30 mL of a fungal spore preparation, whereas tent control goats were intratracheally inoculated with 30 mL of physiologic saline (0.9% NaCI) solution. These treatments were repeated each week for 6 weeks.

RESULTS

Severity of pathologic changes differed significantly among the 7 fungal treatment groups as determined on the basis of gross atelectatic and consolidated lung lesions and histologic lesions of the lungs. Descending order for severity of lesions was Mucor ramosissimus, Trichoderma viride, Chaetomium globosum, Stachybotrys chartarum, Aspergillus fumigatus, Penicillium chrysogenum, and Monotospora lanuginosa. Trichoderma viride spores were the most invasive and were isolated from the bronchial lymph nodes and thoracic fluid of all 6 goats administered this organism. Spores were observed-histologically in lung tissues harvested 72 hours after inoculation from all treatment groups.

CONCLUSIONS AND CLINICAL RELEVANCE

4 of 7 fungal spore types induced significantly larger lung lesions, compared with those induced by the other 3 spore types or those evident in control goats.

Experimental zygomycosis in rabbits: clinicopathological studies

Zygomycosis was produced experimentally in 20 New Zealand white rabbits (Oryctolagus cuniculus) by intra-nasal administration of spores of Absidia corymbifera. Infected animals showed dullness, depression, coughing and mucopurulent nasal discharge, but no mortality. Haematology revealed no significant change in Hb and PCV, but leukocytosis due to neutrophilia in the initial stages of the experiment. There was a significant increase in serum total proteins, creatinine, AST, ALT, total Igs and CICs. A. corymbifera specific IgM and IgG antibodies were detected in the sera of the infected animals. Gross lesions consisted of pneumonic consolidations of the anteroventral lobes of the lungs. Microscopically, histology showed formation of pyogranulommas in the lungs. Fungal elements typical of A. corymbifera were demonstrated in the tissues upto 15 days after infection by special stains and confirmed by indirect immunoperoxidase. Re-isolation of the fungus from lungs was also achieved consistently upto 15 days only. It was concluded that intra-nasal instillation of A. corymbifera in rabbits produced significant clinico-pathological alterations with the lesions confined mainly to the lungs. In the present study, neither systemic dissemination of the disease occurred nor were kidneys site of predilection as reported earlier.

Sequential pathological studies in the udder of goats intramammarily infected with Aspergillus fumigatus

Intramammary inoculation of goats with Aspergillus fumigatus spores resulted in the development of mastitis with characteristic gross and microscopic lesions. The mastitis and the lesions were restricted to the infected udder halves only and there was no dissemination of infection to other tissues of the body. The experiment was continued for 45 days. Gross changes in the infected udder were observed up to the 45th day post-infection. The lesions, in general, included variable sized abscesses in the first 15 days followed by development of varying sized greyish-white nodules in the infected udders. Microscopic changes consisted of granulomatous reaction with well developed granulomas in the infected udders. Hyphae and spores of Aspergillus fumigatus could be demonstrated in sections of the infected udders up to 45 days after infection. Reisolation of the fungus consistently was achieved up to 45 days. It is concluded that intramammary inoculation of Aspergillus fumigatus spores in goats leads to chronic granulomatous mastitis.

Sequential pathological studies in goats infected intratracheally with Aspergillus fumigatus

Intratracheal inoculation of goats with Aspergillus fumigatus spores resulted in the development of characteristic gross and microscopic lesions. The lesions were restricted to lungs and there was no dissemination of infection to other tissues of the body except liver in one goat 16 days after infection. The experiment was continued for 37 days. Gross changes in lungs were observed up to the 24th day post-infection. The lesions, in general, included congestion and oedema in the first 6 days followed by the development of varying greyish-white nodules in the lungs. Microscopic changes consisted of granulomatous reaction with well developed granulomas in lungs. Hyphae and conidiophores with fruiting bodies of Aspergillus fumigatus could be demonstrated in sections up to 24 days of infection. Reisolation of the fungus consistently was achieved up to 24 days. It is concluded that intratracheal inoculation of Aspergillus fumigatus spores in goats leads to pulmonary aspergillosis up to 24 days.