Ineffectiveness of topical antibiotics in treating Acropora spp. affected by white diseases

For many decades, white band disease (WB) and white pox disease (WPX) have been severely impacting populations of the reef building corals Acropora palmata and A. cervicornis throughout the Caribbean region. Even after the major outbreaks in the 1990s and early 2000s, these diseases still occur annually in certain regions of the Caribbean, including in the United States Virgin Islands (USVI). Given the high virulence and infection rates of WB and WPX, mitigation treatments should be explored. It is highly suspected both diseases have bacterial pathogens, even though Henle-Koch’s postulates have not been fulfilled to determine the causative agent for WB nor WPX observed in the USVI. A specialized antibiotic paste utilizing amoxicillin trihydrate has successfully been used in situ to mitigate another disease impacting stony corals, stony coral tissue loss disease (SCTLD). Considering the past success of this topical paste, this study aimed to determine if this treatment could be used on A. palmata and A. cervicornis to treat WPX and WB, respectively. The topical antibiotic paste did not significantly halt disease lesion expansion, nor stop new lesions from forming. Therefore, other mitigation treatments for WB and WPX should be considered.