An Outbreak of Paralytic Shellfish Poisoning in Tasmania

Area of Science:

• Marine biology
• Public health
• Toxicology

Background:

• Paralytic shellfish poisoning (PSP) is a rare illness caused by consuming shellfish contaminated with paralytic shellfish toxins (PST).
• Harmful algal blooms (HABs), which produce PSTs, occur annually on Tasmania's east coast, posing a public health risk as toxins are not destroyed by cooking or freezing.
• Wild shellfish are not routinely monitored, unlike commercial farms, increasing the risk of public exposure to PSTs.

Purpose of the Study:

• To investigate a cluster of PSP cases in Tasmania in 2015.
• To highlight the public health risks associated with consuming wild shellfish from areas affected by harmful algal blooms.
• To recommend strategies for managing PSP risk in Australia.

Main Methods:

• Clinical case identification and symptomology.
• Environmental monitoring of algal blooms and shellfish toxicity.
• Review of historical PSP cases and current surveillance programs.

Main Results:

• Four cases of PSP were identified between October 2-12, 2015, linked to consuming wild mussels from Tasmania's east coast.
• Symptoms included facial numbness, tingling, and muscle weakness, with two individuals requiring brief hospitalization.
• A large bloom of Alexandrium tamarense was detected during the outbreak period.

Conclusions:

• Wild shellfish consumption poses a significant risk for PSP, particularly during harmful algal blooms.
• Public health interventions, including signage and alerts, have been implemented in Tasmania.
• Active surveillance and inter-jurisdictional collaboration are recommended to manage PSP risks across Australia.