First report of an Onchocercidae worm infecting Psychodopygus carrerai carrerai sandfly, a putative vector of Leishmania braziliensis in the Amazon

Abstract

Sandflies are insects of public health interest due to their role as vectors of parasites of the genus Leishmania, as well as other pathogens. Psychodopygus carrerai carrerai is considered an important sylvatic vector of Leishmania (Viannia) braziliensis in Amazonia. In this study, sandflies were collected in a forested area in the Xapuri municipality, in the State of Acre (Northern Brazil). Two Ps. carrerai carrerai females were found parasitized with a larval form of a filarial worm, one in the labium of the proboscis, the other after the head was squashed, suggesting they were infective larvae. Sandflies were identified through morphological characters as well as amplification and sequencing of the cytochrome oxidase gene (COI). This was the first sequence obtained for Ps. carrerai carrerai for this marker. The obtained nematodes were also characterized through direct sequencing of a fragment of COI and 12S genes, both mitochondrial, and ITS1, a nuclear marker. Phylogenetic analyses revealed that the filarial nematodes belong to a species without sequences for these markers in the database, part of family Onchocercidade and closely related to genus Onchocerca (12S tree). Although sandfly infection with nematodes including members of the Onchocercidae has been reported in the Old World, this is the first report of sandfly infection by a member of the Onchocercidae family in the New World, to the best of our knowledge. Considering that the phylogenetic relationships and location in the insect, it can be expected that this is a parasite of mammals and the transmission cycle should be clarified.

Molecular detection of zoonotic filarioids in Culex spp. from Portugal

“…Though this result does not imply any evidence of their role as vectors for this filarial species, the recent findings of Onchocerca sp. larvae from the sand fly Psychodopygus carrerai carrerai (Brilhante et al ., 2020) suggests that insect species, other than simuliids, may acquire mfs of this onchocercid. Though Onchocerca sp.…”

Cutaneous filarioid nematodes of dogs in the United States: Are they emerging, neglected, or underdiagnosed parasites?

“…in natural populations or experimentally. Additionally, in the Amazon of South America, presumed infective larvae of an Onchocerca species most closely related to O. lupi based on phylogenetic analysis using the COI gene were found in the labium of the proboscis and head of two sandflies (Psychodidae, Phlebotominae), suggesting this group of biting flies should also be investigated in relevant O. lupi endemic regions (99).…”

Autochthonous Onchocerca lupi infection of a domestic dog in Austria

“…and the findings of O. lupi DNA in Simuliidae, these have been suggested as potential vectors [ 9 ]. Other arthropods have also been considered, but evidence of competent transmission is still missing [ 10 – 12 ]. This parasite has been documented in Europe, America, Africa, and Asia [ 1 , 13 – 15 ].…”