Ivermectin could help save the endangered Australian sea lion

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Ivermectin is an effective treatment for hookworm in the endangered Australian sea lion, University of Sydney research has found.

Hookworm infection contributes to up to 40 per cent of pup deaths. In December last year, the species was reclassified as ‘endangered’ due to a 64 per cent reduction in offspring over three generations. With fewer than 10,000 of these Australian-native animals remaining, making them a federal government conservation priority, the results are welcome news.

While ivermectin recently gained notoriety as an unproven prophylactic and therapy for COVID-19 (coronavirus), it has long been used in both human and veterinary medicine as a highly effective treatment for parasitic infections.

In the Australian sea lion, topical ivermectin has now been shown to be highly effective against hookworm infection, with an effectiveness rate of 96.4 per cent— comparable to the injected formulation (96.8 per cent).

All Australian sea lion pups become infected with hookworm through ingesting larvae in their mother’s milk within 48 hours of birth.

Researchers believe the demonstrated effectiveness of this minimally invasive and easily applied treatment option for hookworm is the next step in a disease management strategy to assist the conservation of this endangered species.

The findings have been published in the International Journal for Parasitology: Parasites and Wildlife.

During the 2017 Australian sea lion breeding season at Dangerous Reef, South Australia, the researchers conducted a trial whereby a group of 85 pups aged between 10 and 21 days were either administered topical ivermectin, injected ivermectin, or nothing (control group).

Based on the treatment success using the topical drug, they conducted large scale treatment trials in 2019 and 2020-21 at Seal Bay Conservation Park on South Australia’s Kangaroo Island. These trials were done to verify earlier results and determine whether the treatment of pups improved their overall survival.  

The researchers found that optimal outcomes are achieved if pups are treated early, prior to the development of disease.

In addition to the extremely high effectiveness in treating hookworm infection, ivermectin was also found to be an effective lice-killer, reducing infestations by over 80 per cent. Though not deadly, the lice that infest Australian sea lions are bloodsuckers, contributing to blood loss and anaemia (also an impact of hookworm).

The current study is part of pioneering, ongoing research of the Australian sea lion by a group headed by Dr Rachael Gray. The research commenced in 2006.

This article was sourced from The University of Sydney website on the News page.


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