Onchocercidae (Nematoda: Filarioidea) Infecting Colombian Avian Hosts: Insight from Morphotypes of Microfilariae and Molecular Lineages

Members of the Onchocercidae family are parasites that infect a wide range of tetrapods, including wild birds and other animals. In Colombia, studies on avian blood parasites have diagnosed infections with microfilariae in several species using light microscopy. However, no morphological or molecular analyses of these nematodes have been conducted to date. The present study examined samples from 3820 wild birds with material deposited in the biological collection of the Host-Parasite Relationship Study Group since 1999. Of these individuals, 142 (3.7%) were infected with microfilaria and were analyzed using morphological and morphometric measurements. Additionally, 55 samples with blood or tissue preserved in ethanol were analyzed for sequencing of nuclear marker 18S rDNA and mitochondrial markers 12S rDNA and COI. Morphological analyses showed infection by at least one of 13 designed morphotypes of microfilariae. Twenty-nine sequences were obtained (10 of COI, 6 of 12S, and 13 of 18S), corresponding to 21 molecular lineages associated with Onchocercidae. These sequences were associated with the subfamilies Lemdaninae and Splendidofilariinae, the genera Aproctella Cram, 1931, Splendidofilaria Skrjabin, 1923, and Eufilaria Seurat, 1921, and other sequences did not cluster within any genus for which sequences were available for a particular molecular marker. These findings establish the first framework of morphological and molecular diversity of avian Onchocercidae in the megadiverse Neotropical country Colombia, expanding the known distribution of several genera and highlighting the need for further sampling of adult filariids to refine taxonomic resolution.