Wildlife as reservoirs for parasites infecting commercial species: host specificity and a redescription of Kudoa amamiensis from teleost fish in Australia M A A Burger 1 , A C Barnes 2 and R D Adlard 1,3 1 School of Molecular and Microbial Sciences, University of Queensland, St Lucia, Qld, Australia 2 Centre for Marine Studies, University of Queensland, St Lucia, Qld, Australia 3 Biodiversity Program, Queensland Museum, South Brisbane, Qld, Australia Abstract Parasites of the genus Kudoa (Phylum Myxozoa) have long been known to cause considerable los- ses to finfish aquaculture. One such parasite species, Kudoa amamiensis, causes unsightly white cysts in the skeletal muscle of yellowtail kingfish, Seriola quinqueradiata, in Japan rendering the fillets unmarketable. The authors who character- ized K. amamiensis, Egusa & Nakajima, 1980, hypothesized that yellowtail kingfish, as non- natives to the area, were accidental hosts of the parasite and that it normally infects native reef fish (damselfish, Family Pomacentridae). Since then, we have found parasites that are consistent with the description of K. amamiensis in two species of damselfish and one species of carangid fish in Australia, and it has been recorded pre- viously in another species of reef-associated fish. Our morphometric, histological and DNA results suggest that these specimens are K. amamiensis, and are new host records for that species. Fur- thermore, our observations show that reef fish may act as a reservoir of myxozoan infection for commercial species, and as such should be con- sidered an infection pathway for species in aquaculture. Keywords: aquaculture, carangid, Kudoa amamien- sis, Myxosporea, parasite, pomacentrid. Introduction Parasites of the genus Kudoa Meglitsch, 1947 (Myxozoa: Myxosporea) cause losses in finfish aquaculture either by affecting the health of the fish, e.g. Kudoa neurophila (Grossel, Dykova, Handlinger & Munday 2003), which causes men- ingoencephalomyelitis in farmed striped trumpeter, Latris lineata (Forster), or by affecting the market- ability of fish. Well-known examples of the latter include species such as Kudoa thyrsites (Gilchrist, 1924) and Kudoa paniformis Kabata & Whitaker, 1981, which cause post-mortem myoliquefaction, and species that form unsightly, macroscopic, white cysts in fish skeletal muscle such as Kudoa amami- ensis Egusa & Nakajima, 1980, Kudoa clupeidae (Hahn, 1917) and Kudoa iwatai Egusa & Shiomi- tsu, 1983. Kudoa amamiensis caused significant problems in a yellowtail kingfish, Seriola quinqueradiata Tem- minck & Schlegel (Carangidae), farm in Japan during the late 1970s and early 1980s, which resulted in the farmÕs closure (Egusa & Nakajima 1980). Egusa & Nakajima (1980) surveyed other fish occurring near the farm and found that the same type of infection, although at lower intensity, occurred in reef fish from the Family Pomacentri- dae. They hypothesized that the pomacentrids acted as reservoirs of infection for K. amamiensis in the carangid, which were not infected in their natural habitat away from the reef. Similarly, Langdon, Thorne & Fletcher (1992) proposed that clupeoid fish were reservoirs of K. thyrsites infections found in mahi mahi, Coryphaena hippurus L., after the latter Journal of Fish Diseases 2008, 31, 835–844 doi:10.1111/j.1365-2761.2008.00958.x Correspondence R D Adlard, Biodiversity Program, Queens- land Museum, South Brisbane, Qld 4101, Australia (e-mail: robert.adlard@qm.qld.gov.au) 835 Ó 2008 The Authors. Journal compilation Ó 2008 Blackwell Publishing Ltd