Epizootic ulcerative syndrome – First report of evidence from South Africa's largest and premier conservation area, the Kruger National Park

Abstract

This study reports on the first evidence of genomic material of the causative agent for epizootic ulcerative syndrome (EUS), Aphanomyces invadans, from fish in the Limpopo River system and the Kruger National Park, South Africa. Fourteen fish species were collected from various depressions in the floodplains of the Limpopo and Luvuvhu Rivers in the Makuleke Wetlands during 2015 and 2017. A single individual of Clarias gariepinus was found to have a suspected epizootic ulcerative syndrome (EUS) lesion. Samples were collected and evidence of A. invadans DNA in the samples was found through PCR and amplicon sequencing. The spread of EUS into this premier conservation area is of concern as it could potentially spread across borders and into other naïve river systems with important conservation statuses.

Molecular insights into the mechanisms of susceptibility of Labeo rohita against oomycete Aphanomyces invadans

“…Infection with Aphanomyces invadans is a serious disease of freshwater fishes that is characterized by the presence of oomycete hyphae and necrotizing ulcerative lesions, leading to pathognomonic granulomatous response 1 , 2 . The disease, commonly known as epizootic ulcerative syndrome (EUS), was first reported from ayu in Japan 3 and has subsequently been reported from 20 countries across 4 continents 1 and the disease is spreading to newer areas 4 – 6 . To date, more than 160 species of fish have been reported to be susceptible to A. invadans 2 and the host range is expanding 7 – 10 .…”