Abstract
The main motivation for this study was to determine the occurrence of Toxoplasma gondii, a cosmopolitan widespread zoonotic parasite distribution that can infect a wide variety of mammals and birds, in Magellanic penguins (Spheniscus magellanicus) in Brazil. In recent decades there has been a significant increase in the number of penguins originating from Argentinian and Chilean Patagonia, where these birds are born, that arrive on the Brazilian coast, where many of them are stranded and rescued. Tissue samples were collected from 330 individuals surveyed from 2012–2015 at the Institute for Marine Animal Research and Rehabilitation (IPRAM) located in Cariacica, state of Espirito Santo, Brazil. Serum were collected from 145 animals surveyed in 2015 for the detection of anti-T. gondii antibodies using the Modified Agglutination Test (MAT ≥20) and 18 birds were positive, with titers of 20 (7 birds), 40 (9 birds) and 80 (2 birds). Mouse bioassay for the isolation of T. gondii was performed using tissues from 54 penguins that were also surveyed in 2015, but no isolates were obtained. DNA from tissue samples of 330 individuals was PCR amplified and sequenced to detect tissue cyst forming coccidians by using pan sarcocystids-directed primers (based on 18S rDNA). These samples were from animals surveyed in 2015 and from frozen stocked tissues from animals surveyed in the years 2012 and 2013. The positives were PCR amplified and sequenced with genus Sarcocystis-specific primers (based on internal transcribed spacer 1, RNA polymerase beta subunit coding gene, and cytochrome B coding gene) and with Sarcocystis falcatula/Sarcocystis neurona- specific primers (based on surface antigens SAG2, SAG3 and SAG4). Sixteen (3.0%) of pectoral muscle samples were positive by all the seven molecular markers and all the samples were identical to each other. Organisms close related to Sarcocystis falcatula were confirmed in all cases. This is the first report on molecular detection of infection by S. falcatula-related organisms and the first report of seropositivity for T. gondii in free-living Magellanic penguins in Brazil. Felids and didephid opossums are definitive hosts of T. gondii and S. falcatula, respectively. Where the penguins acquire the infective forms of the parasites shed by the terrestrial mammals remains to be elucidated.
Highlights
Tissue cyst forming coccidian is a group of organisms comprising protozoa that form tissue cysts in intermediate hosts
All the samples that tested PCR-18S positive were of pectoral muscles from different birds and were positive by PCRs targeted to internal transcribed spacer 1 (ITS1), cytochrome B (CYTB), RPOB, SAG2, SAG3 and SAG4
Data indicating identity of genetic sequences of penguin Sarcocystis with homologous from Genbank are in S1 Table. This is the first report on molecular detection of infection by S. falcatula-related organisms and the first report of seropositivity for T. gondii in free-living Magellanic penguins in Brazil
Summary
Tissue cyst forming coccidian is a group of organisms comprising protozoa that form tissue cysts in intermediate hosts. This group can be divided into three subfamilies: Sarcocystinae, represented by the genera Sarcocystis; Cystoisosporinae, containing the genus Cystoisospora, and Toxoplasmatinae, with the genera Toxoplasma, Neospora, Hammondia and Besnoitia [1,2]. Toxoplasma gondii is an obligate intracellular parasite that develops asexually in the tissues of intermediate hosts (mammals and birds), infecting even humans. Tissue cysts are found in muscle and central nervous system of homeothermic and poikilothermic animals, i.e., mammals, birds and reptiles; the complete cycle of only 26 of these species is known [1]. The disease has been described in captive psittacids and other orders of birds in captivity, such as Psittaciformes, Passeriformes, Columbiformes, Suliformes and Strigiformes [8,9,10], but is rarely observed in free-living birds [10,11,12,13]
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