Fatal sarcocystosis in psittacine birds from Argentina

Five psittacine birds, one eastern rosella (Platycercus eximius), one rose-ringed parakeet (Psittacula krameri), two eclectus parrot (Eclectus roratus), and one princess parrot (Polytelis alexandrae), all housed in a commercial aviary from La Plata, Buenos Aires, Argentina, suddenly died after a short period of dyspnea. The most significant histopathological findings for all specimens were interstitial exudative pneumonia, with marked congestion and hemorrhage, septa thickening, and massive perivascular lymphoplasmacytic infiltration. Structures compatible with protozoal schizonts were observed in the capillary lumen. No bacterial development was obtained and the real-time PCR for Chlamydia spp. and several psittacine viruses were negative. All the samples resulted negative on the specific PCR for T. gondii. Sarcocystis spp. PCR was positive in the lung and/or liver samples from all birds. The samples showed a restriction pattern of S. neurona and of S. falcatula-like by PCR-RFLP using JNB25-JD396 and JNB33-JNB54 primers, respectively. Sequences obtained from Sarcocystis sp. 18S rRNA and COI gene from 4 birds showed a high identity among them. The 18S rRNA fragment and complete gene sequences obtained showed the highest similarity with S. falcatula and S. speeri sequences but also with S. neurona SN5 isolate sequence. Likewise, COI sequences have 99.89-100% similarity with S. falcatula and S. speeri sequences. Based on all biological and molecular information recorded, we conclude that the etiological agent was S. falcatula-like, close related with the species shed by opossums in South America.