Transmission of iridovirus from freshwater ornamental fish (pearl gourami) to marine fish (rock bream).
Freshwater pearl gourami Trichogaster leeri and seawater rock bream Oplegnathus fasciatus infected by the iridoviruses PGIV-SP and IVS-1 were carrying similar numbers of viral particles (2.52 x 10(8) and 2.46 x 10(8) viral genome copies mg(-1) spleen tissue, respectively). The viral genome copy number for both iridoviruses decreased much faster in seawater than in freshwater, reaching a concentration of less than 0.5%, versus 26 to 54% in freshwater, after 4 d of incubation at 25 degrees C. The decrease in copy number altered the infectivity of the viruses, as reflected by the decreased cumulative mortality of rock bream injected intraperitoneally with the incubated iridoviruses. Moreover, uninfected rock bream cohabitated with PGIV-SP-challenged rock bream showed 100% cumulative mortality; a similar experiment using IVS-1 had the same result, implying the potential for iridoviral transmission from freshwater ornamental fish to marine fish even in a marine environment. Of 58 outwardly healthy marine fish groups collected from various markets, 2 rock bream groups and 1 sea perch group Lateolabrax sp. tested positive for PGIV-SP by 2-step polymerase chain reaction (PCR). Thus, PGIV-SP from freshwater ornamental fish may have crossed both environmental and species barriers to infect marine fish such as rock bream.
Jeong
Joon Bum
JB
Faculty of Applied Marine Science, College of Ocean Science, Cheju National University, Ara 1 dong, Jeju-do 690-756, South Korea.
Cho
Hye Jin
HJ
Jun
Lyu Jin
LJ
Hong
Su Hee
SH
Chung
Joon-Ki
JK
Jeong
Hyun Do
HD
D000818:Animals; D001483:Base Sequence; D005393:Fish Diseases / Q000635:transmission / Q000821:virology*; D005618:Fresh Water; D016679:Genome, Viral; D017994:Iridovirus / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D010473:Perciformes / Q000821:virology*; D012623:Seawater; D013997:Time Factors; D014777:Virus Diseases / Q000635:transmission / Q000662:veterinary* / Q000821:virology