Comparison between immunotherapy and caspofungin as agents to treat experimental pythiosis in rabbits

• Published in: Journal de mycologie médicale 2008-09, Vol.18 (3), p.129-133
• Main Authors: Pereira, D.I.B., Santurio, J.M., Alves, S.H., de Azevedo, M.I., Silveira, F., da Costa, F.F., Sallis, E.S.V., Pötter, L., Ferreiro, L.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Caspofungin; Caspofungine; Fundamental and applied biological sciences. Psychology; Immunotherapy; Immunothérapie; Infectious diseases; Lapins; Medical sciences; Microbiology; Miscellaneous; Mycology; Mycoses; Pitium Vac; Pythiose; Pythiosis; Pythium insidiosum; Rabbits
• ISSN: 1156-5233; 1773-0449
• DOI: 10.1016/j.mycmed.2008.05.001

Pythiosis is an emerging disease that is difficult to treat and is caused by the oomycete Pythium insidiosum. This study evaluated the efficacy of two different treatments for pythiosis using rabbits as an experimental model. Fifteen rabbits subcutaneously inoculated with P. insidiosum zoospores were divided into three groups of five animals (group 1, control; group 2, treated with Pitium Vac ® immunotherapic and group 3, treated with caspofungin). The treatments were started 25 days after the inoculation, and consisted of: (1) eight doses of the immunotherapic administered at 14-day intervals and (2) 1 mg/kg per day of caspofungin during 20 consecutive days. The animals were necropsied 18 weeks after the experiment onset, and lesion fragments were collected for histopathologic and morphometric analysis. The animals in the control group displayed larger lesion sizes compared to the animals treated with Pitium Vac ® or caspofungin ( P < 0.05). The histological aspect of the lesions was similar among the groups under study, and the morphometric evaluation showed that the animals in groups 2 and 3 had lower amounts of hyphae in necrotic areas ( P < 0.05). The results of the present study indicate that, even though the treatments did not differ significantly, the immunotherapic treatment is still the best alternative to treat pythiosis due to its lower cost. Caspofungin fungistatic effect on P. insidiosum in addition to its high cost makes its use for the treatment of animal pythiosis impractical. La pythiose est une maladie émergente très difficile à traiter due au développement de l’oomycète Pythium insidiosum. Le but de cette étude est d’évaluer l’efficacité de deux traitements différents de la pythiose expérimentale chez le lapin. Trois groupes de cinq lapins sont inoculés par la voie sous-cutanée avec une suspension de zoospores de P. insidiosum. Les animaux du premier groupe représentent les témoins. Le vingt-cinquième jour après l’inoculation, le second groupe reçoit huit doses de l’immunothérapie qui sont administrées à 14 jours d’intervalle et les lapins du troisième lot sont traités avec de la caspofungine: 1 mg/kg par jour pendant 20 jours consécutifs. Les animaux sont sacrifiés 18 semaines après le début de l’expérience et des biopsies sont réalisées au niveau des lésions pour des études morphométriques et histopathologiques. Des lésions plus importantes en dimension sont constatées chez le groupe témoin par rapport aux animaux traités avec le Piti