title: Toltrazuril does not show an effect against pigeon protozoal encephalitis.
abstract: The protozoan parasite Sarcocystis calchasi causes a severe neurologic disease in domestic pigeons (Columba livia f. dom.) named pigeon protozoal encephalitis. Recently, the parasite has also been reported in psittacines causing a virtually identical disease with fatal outcome. So far, an etiological treatment of S. calchasi infections in pigeons or psittacines is unknown. The present study evaluates the effectiveness of the anticoccidian drug toltrazuril against S. calchasi and the influence of the timepoint of treatment. Therefore, nine domestic pigeons were inoculated with 400 S. calchasi sporocysts and treated with toltrazuril (25 mg/kg) in groups of three pigeons each at dpi 10/11 and dpi 40/41 and on two consecutive days at the onset of neurologic signs. After euthanasia at dpi 73, tissue samples including brain and skeletal muscles were examined by histology and S. calchasi-specific real-time PCR. All pigeons independent of the group developed neurologic signs from dpi 49 onwards. Histology identified sarcocysts in the skeletal muscles and a granulomatous encephalitis in the brains. The relative amount of S. calchasi DNA was on a comparable level in all pigeons. Consequently, toltrazuril was demonstrated to be not effective against S. calchasi with the applied treatment regime. Longer treatment periods or agents other the toltrazuril may be considered for further investigations. So far, preventive measures like roofing of aviaries for prevention of infection and regular disinfection remain the most important factor in the control of S. calchasi infections.
authors: Clinic for Birds, Reptiles, Amphibians and Fish, Justus Liebig University Giessen, Frankfurter Str. 91-93, 35392, Giessen, Germany, Kristina.Maier@vetmed.uni-giessen.de.
authors: Kristina
authors: K
authors: Maier
authors: P
authors: P
authors: Olias
authors: A D
authors: AD
authors: Gruber
authors: M
authors: M
authors: Lierz
mesh_terms: D000818:Animals; D001715:Bird Diseases / Q000188:drug therapy* / Q000469:parasitology; D010856:Columbidae / Q000469:parasitology*; D004660:Encephalitis / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary*; D012522:Sarcocystis / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D012523:Sarcocystosis / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary*; D014227:Triazines / Q000008:administration & dosage*
chemical_list: D014227:Triazines; C036670:toltrazuril
references: Vet Parasitol. 2000 Sep 20;92(2):165-9
references: 10946140
references: Parasitol Res. 2010 Feb;106(3):577-85
references: 20033211
references: Vet Parasitol. 2011 Feb 10;175(3-4):230-6
references: 21074324
references: Zentralbl Bakteriol Mikrobiol Hyg A. 1981;250(1-2):268-76
references: 6797157
references: J Vet Diagn Invest. 2013 Nov;25(6):775-81
references: 24081928
references: J Parasitol. 2006 Jun;92(3):637-43
references: 16884012
references: Avian Pathol. 2015;44(1):5-12
references: 25338141
references: Avian Pathol. 2009 Apr;38(2):121-8
references: 19322710
references: Vet Res. 2013 Feb 11;44:10
references: 23398807
references: J Am Vet Med Assoc. 2012 Feb 1;240(3):324-8
references: 22256850
references: Vet Parasitol. 2001 Jan 20;94(4):257-64
references: 11137273
references: Vet Ther. 2000 Spring;1(2):125-32
references: 19757559
references: Vet Parasitol. 2003 May 30;114(2):123-30
references: 12781474
references: Vet Ther. 2001 Summer;2(3):215-22
references: 19746664
references: Am J Vet Res. 2008 Mar;69(3):396-402
references: 18312139
references: Avian Dis. 2010 Sep;54(3):1032-7
references: 20945785
references: Res Vet Sci. 1975 Sep;19(2):204-8
references: 1166126
references: Vet Parasitol. 2014 Feb 24;200(1-2):59-65
references: 24360290
references: Vet Clin Pathol. 2010 Mar;39(1):105-12
references: 19548967
references: Transbound Emerg Dis. 2011 Dec;58(6):526-30
references: 21848932