Disease and immunity in Caribbean and Indo-Pacific zooxanthellate corals

Abstract

Since the mid-1990s, coral diseases have increased in number, species affected, and geographic extent. To date, 18 coral diseases, affecting at least 150 scleractinian, gorgonian, and hydrozoan zooxanthellate species, have been described from the Caribbean and the Indo-Pacific. These diseases are associated with pathogens including bacteria, cyanobacteria, fungi, and protists and with abiotic stressors including elevated seawater temperature, sedimentation, eutrophication, and pollution. Etiologies of only 5 of the 18 coral diseases have been determined through fulfillment of Koch's postulates. Corals and other invertebrates utilize innate immune mechanisms including physiochemical barriers and cellular and humoral defenses against pathogens. Here we review the described coral diseases, known etiologies, and efforts to determine unknown etiologies. We define disease terms, discuss the limitations of Koch's postulates, describe alternative techniques for identifying disease-causing organisms, and review coral immunology.

Potential role of viruses in white plague coral disease

“…These disease signs and epidemiological properties are consistent with those previously reported for WP (reviewed in Bythell et al, 2004;Sutherland et al, 2004;Brandt et al, 2013), and tissue loss rates were most similar to reports of WP type I disease (Dustan, 1977;Sutherland et al, 2004).…”

“…Such epizootics are of concern because they have contributed to declines in coral abundance and cover (Gardener et al, 2003;Rogers, 2009). However, of the 420 described global coral diseases, only 6-8 have pathogens ascribed to their etiology (Green and Bruckner, 2000;Sutherland et al, 2004;Rosenberg et al, 2007;Bourne et al, 2009;Pollack et al, 2011). One coral disease of particular ecological importance is white plague (WP), a rapid tissue loss disease that affects multiple species of Caribbean corals, including dominant reef-building Montastraea species.…”

Bioindicators of changes in water quality on coral reefs: review and recommendations for monitoring programmes

“…At present, approximately 20 diseases have been identified that affect more than 100 species of corals (Sutherland et al 2004). Most diseases are caused by pathogens such as bacteria, cyanobacteria and fungi.…”

“…Most diseases are caused by pathogens such as bacteria, cyanobacteria and fungi. Pathogens can be delivered to coral reefs via terrestrial runoff (Sutherland et al 2004), or transmitted by biological vectors (Sussman et al 2003). Recent studies have highlighted the role of elevated levels of dissolved organic carbon, a common component of sewage and organic discharge, to tissue sloughing (symptomatic of many diseases) and increased coral mortality (Table 2; Kuntz et al 2005;Kline et al 2006).…”

“…Coral diseases are recognised as a major form of disturbance for coral reefs (Sutherland et al 2004) and anthropogenic influences are considered to increase their prevalence (Green and Bruckner 2000;Bruno et al 2003). At present, approximately 20 diseases have been identified that affect more than 100 species of corals (Sutherland et al 2004).…”