Data from: White Syndrome in Acropora muricata: Non-specific bacterial infection and ciliate histophagy

Selective antibiotic treatment of White Syndrome (WS)-affected corals
(Acropora muricata) from Fiji was used to identify 3 potential bacterial
pathogens of the disease. Interestingly, the suite of bacterial associates
of the disease was different to that recently identified using identical
primer sets for WS on the GBR and in the Solomon Islands. In addition to
the three bacterial pathogenic candidates and as previously shown for WS
and more recently for White Band Disease (WBD) in the Caribbean, all
samples of the disease were specifically associated with the histophagous
ciliate Philaster lucinda. From the pattern of disease progression and
histopathology in relation to the selective elimination of microbial
groups, we conclude that these ‘white’ diseases are a result of a
non-specific bacterial infection and a ‘secondary’ infection by the P.
lucinda ciliate. Although we have not observed the initiation of
infection, a non-specific, multi-species bacterial infection appears to be
a co-requirement for WS lesion progression and we hypothesize that the
bacterial infection occurs initially, weakening the defences of the host
to predation by the ciliates. Such ciliate histophagy, gives rise to the
characteristic white band of denuded coral skeleton that gives these
diseases their names. The characteristics of the microbial communities of
WBD and WS appear identical, and since the bacterial associates of WS vary
geographically (and/or temporally), there appears to be no logical
distinction between WS in the Indo-Pacific and WBD in the Caribbean.