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Emerging pathogen of wild amphibians in frogs (Rana catesbeiana) farmed for international trade.

Mazzoni R - Emerging Infect. Dis. (2003)

Bottom Line: Chytridiomycosis is an emerging disease responsible for a series of global declines and extinctions of amphibians.We report the causative agent, Batrachochytrium dendrobatidis, in North American bullfrogs (Rana catesbeiana) farmed for the international restaurant trade.Our findings suggest that international trade may play a key role in the global dissemination of this and other emerging infectious diseases in wildlife.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Investigaciones Pesqueras, Montevideo, Uruguay. andrew.cunningham@ioz.ac.uk

ABSTRACT
Chytridiomycosis is an emerging disease responsible for a series of global declines and extinctions of amphibians. We report the causative agent, Batrachochytrium dendrobatidis, in North American bullfrogs (Rana catesbeiana) farmed for the international restaurant trade. Our findings suggest that international trade may play a key role in the global dissemination of this and other emerging infectious diseases in wildlife.

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Related in: MedlinePlus

a and b, histopathologic findings from infected frogs. Characteristic sporangia (s) containing zoospores (z) are visible in the epidermis (asterisk, superficial epidermis; arrow, septum within an empty sporangium; bars, 10 μm. c, Skin smear from infected frog, stained with 1:1 cotton blue and 10% aqueous potassium hydroxide (aq KOH) (D, developing stages of Batrachochytrium dendrobatidis; arrow, septum within a sporangium; bar, 10 μm. d, Electron micrograph of an empty sporangium showing diagnostic septum (arrow) (bar, 2 μm).
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Figure 1: a and b, histopathologic findings from infected frogs. Characteristic sporangia (s) containing zoospores (z) are visible in the epidermis (asterisk, superficial epidermis; arrow, septum within an empty sporangium; bars, 10 μm. c, Skin smear from infected frog, stained with 1:1 cotton blue and 10% aqueous potassium hydroxide (aq KOH) (D, developing stages of Batrachochytrium dendrobatidis; arrow, septum within a sporangium; bar, 10 μm. d, Electron micrograph of an empty sporangium showing diagnostic septum (arrow) (bar, 2 μm).

Mentions: Routine bacteriologic tests (culture on blood agar for 24 h and 48 h at 37°C) were performed on liver, kidney, and heart blood collected from a sample of euthanized frogs, but these tests did not implicate causative pathogens. Necropsies were performed systematically on 30 frogs, but no gross abnormalities of the viscera were found. Internal organs (lung, liver, kidney, heart, and spleen) from 10 of these frogs were examined by histologic testing, but no lesions were detected. Examination of skin smears (wet-mounted, stained with a 1:1 mixture of cotton blue [parker ink] and 10% aq. KOH), and histologic and ultrastructural analyses of fixed skin indicated subspherical developing sporangia and flask-shaped mature sporangia within the superficial layer of the epidermis (Figure). Septa, characteristic of B. dendrobatidis, were observed in many developing sporangia (Figure). Slight hyperplasia of the keratinized cells of the stratum corneum and stratum granulosum was observed in some areas where chytrid developmental stages were present. Specific examinations for viruses were not performed, as facilities to test for viruses were unavailable.


Emerging pathogen of wild amphibians in frogs (Rana catesbeiana) farmed for international trade.

Mazzoni R - Emerging Infect. Dis. (2003)

a and b, histopathologic findings from infected frogs. Characteristic sporangia (s) containing zoospores (z) are visible in the epidermis (asterisk, superficial epidermis; arrow, septum within an empty sporangium; bars, 10 μm. c, Skin smear from infected frog, stained with 1:1 cotton blue and 10% aqueous potassium hydroxide (aq KOH) (D, developing stages of Batrachochytrium dendrobatidis; arrow, septum within a sporangium; bar, 10 μm. d, Electron micrograph of an empty sporangium showing diagnostic septum (arrow) (bar, 2 μm).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3020601&req=5

Figure 1: a and b, histopathologic findings from infected frogs. Characteristic sporangia (s) containing zoospores (z) are visible in the epidermis (asterisk, superficial epidermis; arrow, septum within an empty sporangium; bars, 10 μm. c, Skin smear from infected frog, stained with 1:1 cotton blue and 10% aqueous potassium hydroxide (aq KOH) (D, developing stages of Batrachochytrium dendrobatidis; arrow, septum within a sporangium; bar, 10 μm. d, Electron micrograph of an empty sporangium showing diagnostic septum (arrow) (bar, 2 μm).
Mentions: Routine bacteriologic tests (culture on blood agar for 24 h and 48 h at 37°C) were performed on liver, kidney, and heart blood collected from a sample of euthanized frogs, but these tests did not implicate causative pathogens. Necropsies were performed systematically on 30 frogs, but no gross abnormalities of the viscera were found. Internal organs (lung, liver, kidney, heart, and spleen) from 10 of these frogs were examined by histologic testing, but no lesions were detected. Examination of skin smears (wet-mounted, stained with a 1:1 mixture of cotton blue [parker ink] and 10% aq. KOH), and histologic and ultrastructural analyses of fixed skin indicated subspherical developing sporangia and flask-shaped mature sporangia within the superficial layer of the epidermis (Figure). Septa, characteristic of B. dendrobatidis, were observed in many developing sporangia (Figure). Slight hyperplasia of the keratinized cells of the stratum corneum and stratum granulosum was observed in some areas where chytrid developmental stages were present. Specific examinations for viruses were not performed, as facilities to test for viruses were unavailable.

Bottom Line: Chytridiomycosis is an emerging disease responsible for a series of global declines and extinctions of amphibians.We report the causative agent, Batrachochytrium dendrobatidis, in North American bullfrogs (Rana catesbeiana) farmed for the international restaurant trade.Our findings suggest that international trade may play a key role in the global dissemination of this and other emerging infectious diseases in wildlife.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Investigaciones Pesqueras, Montevideo, Uruguay. andrew.cunningham@ioz.ac.uk

ABSTRACT
Chytridiomycosis is an emerging disease responsible for a series of global declines and extinctions of amphibians. We report the causative agent, Batrachochytrium dendrobatidis, in North American bullfrogs (Rana catesbeiana) farmed for the international restaurant trade. Our findings suggest that international trade may play a key role in the global dissemination of this and other emerging infectious diseases in wildlife.

Show MeSH
Related in: MedlinePlus