Disease Diagnostics and Potential Coinfections by Vibrio coralliilyticus During an Ongoing Coral Disease Outbreak in Florida

A deadly coral disease outbreak has been devastating the Florida Reef Tract since 2014. This disease, stony coral tissue loss disease (SCTLD), affects at least 22 coral species causing the progressive destruction of tissue. The etiological agents responsible for SCTLD are unidentified, but pathogenic bacteria are suspected. Virulence screens of 400 isolates identified four potentially pathogenic strains of Vibrio spp. subsequently identified as V. coralliilyticus. Strains of this species are known coral pathogens; however, cultures were unable to consistently elicit tissue loss, suggesting an opportunistic role. Using an improved immunoassay, the VcpA RapidTest, a toxic zinc-metalloprotease produced by V. coralliilyticus was detected on 22.3% of diseased Montastraea cavernosa (n = 67) and 23.5% of diseased Orbicella faveolata (n = 24). VcpA+ corals had significantly higher mortality rates and faster disease progression. For VcpA– fragments, 21.6% and 33.3% of M. cavernosa and O. faveolata, respectively, died within 21 d of observation, while 100% of similarly sized VcpA+ fragments of both species died during the same period. Further physiological and genomic analysis found no apparent differences between the Atlantic V. coralliilyticus strains cultured here and pathogens from the Indo-Pacific but highlighted the diversity among strains and their immense genetic potential. In all, V. coralliilyticus may be causing coinfections that exacerbate existing SCTLD lesions, which could contribute to the intraspecific differences observed between colonies. This study describes potential coinfections contributing to SCTLD virulence as well as diagnostic tools capable of tracking the pathogen involved, which are important contributions to the management and understanding of SCTLD

Relentless Placoid Chorioretinitis: A New Entity or an Unusual Variant of Serpiginous Chorioretinitis?

OBJECTIVE To characterize an unusual clinical entity resembling acute posterior multifocal placoid pigment epitheliopathy (APMPPE) and serpiginous choroiditis but with an atypical clinical course. PATIENTS We describe 6 patients, aged 17 through 51 years, exhibiting this unusual entity who were seen at 6 different centers from 1984 to 1997. RESULTS The acute retinal lesions in this series were similar to those of APMPPE or serpiginous choroiditis, both clinically and on fluorescein and indocyanine green angiography. However, the clinical course, number of lesions, and location of these lesions were atypical. These patients had evidence of numerous posterior and peripheral retinal lesions predating or occurring simultaneously with macular involvement. Older, healing pigmented lesions were often accompanied by the appearance of new active white placoid lesions. Additionally, these cases all demonstrated prolonged periods of activity resulting in the appearance of more than 50 and sometimes hundreds of lesions scattered throughout the fundus. Growth of subacute lesions and the appearance of new lesions continued for 5 to 24 months after initial examination, and relapses were common. CONCLUSIONS This entity has clinical features similar to APMPPE and serpiginous choroiditis but has a prolonged progressive clinical course and widespread distribution of lesions. It may represent a variant of serpiginous choroiditis or may be a new entity. We call it relentless placoid chorioretinitis.Arch Ophthalmol. 2000;118:931-938--