Causes of Fatal Cyathostomiasis in Brown Booby (Sula leucogaster) from Brazil: Identification of Pathogen and Implications for Management

Fatal infection by Cyathostoma (Cyathostoma) phenisci (Nematoda: Syngamidae), was identified in 2 of 52 brown boobies (Sula leucogaster) collected on beaches in the state of Rio de Janeiro, Brazil, and admitted to the veterinary clinic for rehabilitation. Both infected birds were in poor physical condition, with atrophied pectoral muscles, and died soon after starting treatment. The parasitological and pathological examination of the carcasses revealed the presence of C. (C.) phenisci in the trachea, resulting in tracheitis, as well as severe parasitic granulomatous bronchopneumonia caused by eggs deposited in the lungs. In our opinion, these serious pathological changes were the primary cause of chronic respiratory illness. This is the first description of fatal cyathostomiasis in a fish-eating avian host caused by infection by a member of the subgenus Cyathostoma (Cyathostoma). Therefore, it is reasonable to consider C. (C.) phenisci to be a real threat to a wide range of their definitive hosts, and cyathostomiasis should be considered in the differential diagnosis for fish-eating marine birds, even in cases without respiratory signs. This is also the first record of the genus Cyathostoma in Brazil.

Taxonomic status of Syngamus nematodes parasitizing passeriform hosts from Central Europe: Morphological, morphometric and molecular identification

The systematic position and validity of species within genus Syngamus have always been controversial. In this present work, we evaluated the taxonomic status and phylogenetic relationships between three species of Syngamus nematodes (Syngamus trachea, Syngamus taiga and Syngamus merulae) and one taxa, determined only to the generic level, collected from respiratory tracts of passeriform hosts from Central Europe using newly obtained sequences of 2 nuclear markers (internal transcribed spacers 1 and 2 [ITS1, ITS2]) and a fragment of mitochondrial cytochrome oxidase I [COI] gene. Our results clearly showed that S. trachea, S. taiga and S. merulae are valid, molecularly and morphologically distinct species. Moreover, molecular analysis of adult female of Syngamus sp. collected from tracheae of the European robin Erithacus rubecula clearly indicate that these comprise separate species. In the derived phylogeny, the Syngamus clade is divided into two sub-clades: one comprised Syngamus species with a characteristic, well-developed cuticular collar around the oral opening (S. trachea and S. taiga) and a second that groups taxa without or with rudimentary collar (S. merulae and currently sequenced Syngamus sp. from Erithacus rubecula). These results clearly suggest that the degree of collar development (well-developed vs. rudimentary/absent) may be an important phylogenetic feature for determining the structure of the genus Syngamus on subgeneric level. Additionally, our results support historical division of the genus Syngamus into two subgenera S. (Syngamus) and S. (Ornithogamus).