Amphibian pathogens in Southeast Asian frog trade

Area of Science:

• Veterinary Medicine
• Wildlife Health
• Pathogen Surveillance

Background:

• Amphibian trade networks are recognized pathways for pathogen dissemination.
• Understanding amphibian health in trade is crucial for disease control and conservation.
• Southeast Asia is a significant hub for amphibian trade, encompassing food and pet markets.

Purpose of the Study:

• To assess the prevalence of Batrachochytrium dendrobatidis (Bd) and ranavirus in amphibians traded in Southeast Asia.
• To evaluate the general clinical condition of traded amphibians, with a focus on dermatological health.
• To identify potential public health risks associated with amphibian trade, particularly concerning farmed species.

Main Methods:

• Conducted field sampling across 51 sites in Lao PDR, Cambodia, Vietnam, and Singapore.
• Screened 2,389 individual amphibians for Batrachochytrium dendrobatidis (Bd) using molecular methods.
• Screened 74 amphibians for ranavirus and performed clinical and histological examinations for dermatological conditions and signs of sepsis.

Main Results:

• Batrachochytrium dendrobatidis (Bd) was detected infrequently (1/347 in Cambodia, 13/419 in Singapore), with none found in Lao PDR or Vietnam.
• Ranavirus was not detected in any of the sampled amphibians from Cambodia or Vietnam.
• All East Asian bullfrogs (Hoplobatrachus rugolosus) farmed in Vietnam displayed skin lesions, with some showing signs of bacterial sepsis and Mycobacterium infection.

Conclusions:

• Batrachochytrium dendrobatidis (Bd) appears to be currently rare in the amphibian trade within Southeast Asia.
• Mycobacterium-associated disease in farmed Hoplobatrachus rugolosus poses a potential public health risk.
• Enhanced biosecurity measures are essential for amphibian farming and trade to mitigate disease spread and protect public health.