• Charles Sturt University researchers in collaboration with the NSW Department of Primary Industries and the Narrandera Fisheries Centre have discovered dangerous parasites in native Australian freshwater fish
• The parasite species Eustrongylides excisus was found in Murray cod, galaxiids, a hybrid of Murray cod and Trout cod and can also infect humans
• Australia’s expertise about parasites in humans, aquatic animals and wildlife has been diminishing rapidly, leading to misdiagnosis and underdiagnosis of parasite infections in humans and animals

Another invasive parasite has been found in Australian native animals which can infect humans.

Charles Sturt University researchers in collaboration with the NSW Department of Primary Industries and the Narrandera Fisheries Centre have discovered the parasite species Eustrongylides excisus within native fish including Murray cod, galaxiids, a hybrid of Murray cod and Trout cod.

The parasite was also found in various native birds such as cormorants.

Charles Sturt Professor in Veterinary Parasitology within the Charles Sturt School of Agricultural, Environmental and Veterinary Sciences Shokoofeh Shamsi led the research which unearthed a high degree of infection within the fish from the parasites which were deeply embedded in theirflesh.

“These parasites were checked both genetically and morphologically and found to be an introduced and invasive species called Eustrongylides excisus,” Professor Shamsi said.

“Unfortunately, this parasite can also infect humans if they eat undercooked and infected fish.”

The fish were collected from Cataract Dam south of Sydney and from other locations within NSW and submitted to a Charles Sturt University parasitology lab for testing.

Professor Shamsi said the team also found native birds, such as various native cormorants that were infected with this parasite.

“The worm burrowed into the stomach of these birds, creating a hole, which resulted in death,” Professor Shamsi said.

“This is similar to what happens inside humans when we get infected from this parasite - the worm burrows into our gut and tissue.”

The research commenced in 2021 and ran until March 2023 with a focus on environmental health and food safety.

“Our team is passionate about environmental health and food safety to influence strengthened biosecurity regulations,” Professor Shamsi said.

“This is not the first time that our team has provided evidence of the presence of an invasive species in Australia which suggests biosecurity gaps in current biosecurity protocols.

“It heightens the need for risk assessment studies to include parasitologists,” she said.

Professor Shamsi said Australia’s expertise of parasites in humans, aquatic animals and wildlife had been diminishing at a rapid rate leading to misdiagnosis and underdiagnosis of parasite infections in humans and animals.

“We are urgently calling for investment into research and capacity building in the field of parasitology which is an increasingly fast-changing environment,” Professor Shamsi said.

“This parasite is usually found in areas that are high in agricultural fertilizers.”

Professor Shamsi said there was scope for increased resources to invest more into the containment of this invasive parasite.

“For example, we need to find out what the source of infection is for fish, and what the distribution of this parasite is in Australia,” Professor Shamsi said.

“Resources such as fact sheets on this parasite could be created for recreational fisher people, fish farmers, and environmental activists who relocate fish from one location to another and could also be used by medical doctors.”

ENDS