The pathology of systemic iridoviral disease in fish.
Iridoviruses have been associated with severe disease and economic loss in farmed food fish and ornamental fish, with mortality often reported to reach 50% or more. In the present study, three tropical marine food fish species and four tropical freshwater ornamental fish species with systemic iridovirus infections were examined histopathologically and ultrastructurally. Light microscopy consistently revealed pale to intensely basophilic hypertrophied virus-infected cells in spleen, kidney and intestine from all seven species. Ultrastructural examination showed changes in the vascular endothelium overlying hypertrophied virus-infected cells suggestive of pressure necrosis. Viral isolation was improved by the use of fibroblastic cell lines. This, together with the sub-endothelial location of infected cells in all infected species examined, suggests that systemic iridoviruses are mesotheliotropic.
Gibson-Kueh
S
S
Aquatic Animal Health Branch, Animal and Plant Health Laboratory Division, AgriFood and Veterinary Authority of Singapore, 60 Sengkang East Way, Singapore 548596.
Netto
P
P
Ngoh-Lim
G H
GH
Chang
S F
SF
Ho
L L
LL
Qin
Q W
QW
Chua
F H C
FH
Ng
M L
ML
Ferguson
H W
HW
D000818:Animals; D002460:Cell Line; D004730:Endothelium, Vascular / Q000473:pathology / Q000821:virology; D005347:Fibroblasts / Q000473:pathology / Q000821:virology; D005393:Fish Diseases / Q000473:pathology*; D005399:Fishes / Q000821:virology*; D007422:Intestines / Q000473:pathology / Q000821:virology; D017994:Iridovirus / Q000302:isolation & purification* / Q000648:ultrastructure; D007668:Kidney / Q000473:pathology / Q000821:virology; D013154:Spleen / Q000473:pathology / Q000821:virology; D014329:Tropical Climate; D014777:Virus Diseases / Q000473:pathology / Q000662:veterinary*; D014779:Virus Replication