Now showing items 1-4 of 4

    • Conference paper

      Aeromonas hydrophila in the epizootic ulcerative syndrome (EUS) of snakehead, Ophicephalus striatus, and catfish, Clarias batrachus: quantitative estimation in natural infection and experimental induction of dermo-muscular necrotic lesion 

      Snakehead (Ophicephalus striatus) and catfish (Clarias batraclus) with the Epizootic Ulcerative Syndrome (EUS) were sampled for bacteria. Total bacterial counts of skin and muscle/dermal lesions revealed mean colony forming units (CFU) per gram tissue of 1.22 x 103, 1.40 x 105, 5.31 x 195 and 1.14 x 107 in apparently normal, slightly lesioned, moderately lesioned and severely lesioned snakehead samples, respectively. In catfish, mean CFU per gram tissue were 4.30 x 104 and 2.00 x 105 in apparently normal and slightly lesioned specimens, respectively. Kidney samples likewise revealed the presence of bacteria. Bacteria isolated on trypticase soy agar and Rimler-Shotts medium were predominantly Aeromonas hydrophila occurring in 90% of snakeheads and in 33% of catfish specimens. Infection experiments of A. hydrophila injected intramuscularly into healthy snakehead and catfish induced dermo-muscular necrotic lesions. A dose of at least 106 cells of A. hydrophila was required to induce EUS-like lesions in snakehead and catfish at 21-25 degree C in 24-96 h.
    • Article

      Establishment of cell lines from catfish (Clarias batrachus) and snakeheads (Ophicephalus striatus) 

      GD Lio-Po, GS Traxler & LJ Albright - Asian Fisheries Science, 1999 - Asian Fisheries Society
      Primary cell cultures from catfish (Clarias batrachus) and snakeheads (Ophicephalus striatus) were prepared from whole fry and fingerling organ tissues of the brain, fins, gonad, heart, kidney, liver, skin and spleen. Four methods were tried: method A, wherein explants were placed onto the surface of 25-cm2 Primaria flasks (Falcon), allowed to attach for an hour before addition of Leibovitz medium (L-15) supplemented with 15% fetal bovine serum (FBS)(L15-15); Method B, wherein explants were inoculated into 25-cm2 Primaria flasks (Falcon) already containing L15-15; Method C, which required forcing minced organ sections through a stainless steel sieve with the aid of a syringe plunger into a petri dish containing L15-15 medium; and Method D, wherein immersed sections of minced tissues to 0.5% trypsin-EDTA were slowly agitated using a magnetic stirrer for one hour at 25°C. Method B was most effective in the establishment of cell cultures from both fish species. Passage numbers of the cells are to date catfish gonad (CFG) P-56, catfish heart (CFH) P-51, catfish kidney (CFK) P-7, catfish liver (CFL) P-8, catfish spleen (CFS) P-54, snakehead gonad (SHG) P-26, snakehead heart (SHH) P-22, snakehead kidney (SHK) P-19, snakehead liver (SHL) P-49 and snakehead spleen (SHS) P-76. Attempts to derive primary cell cultures from organ tissues of the brain, fins, skin and whole fry were unsuccessful. Established cells were fibroblastic. The cells grew rapidly and became confluent 24 h after seeding at 20 and 25°C. Both SHS and CFS were susceptible to a virus isolated from EUS-affected fish in the Philippines. The cells were best maintained at 20°C and stored in liquid nitrogen or -70°C.
    • Article

      Experimental induction of lesions in snakeheads (Ophicephalus striatus) and catfish (Clarias batrachus) with Aeromonas hydrophila, Aquaspirillum sp., Pseudomonas sp. and Streptococcus sp. 

      GD Lio-Po, LJ Albright, C Michel & EM Leaño - Journal of Applied Ichthyology, 1998 - Wiley-Blackwell
      Isolates of Aquaspirilluni sp., Pseudomonas sp., and Streptococcus sp. recovered from epizootic ulcerative syndrome (EUS)-affected snakeheads (Ophicephalus striatus) in Thailand as well as an isolate of Aeromonas hydrophila recovered from EUS-affected snakeheads in the Philippines were characterized and identified. Each isolate was injected intramuscularly (IM) into healthy catfish (Clarias batrachus) and snakeheads (O. striatus). Results showed in tests with C. batraclius that 24 h after injection, Aquaspirillum sp., Pseudomonas sp., Streptococcus sp. and A. hydrophila induced slight, slight, moderate and severe dermomuscular necrotic lesions, respectively. Among O. striatus, only A. hydrophila induced severe lesions. Streptococcus sp. induced slight lesions 2 days post-injection which healed rapidly, while Aquaspirillum sp. and Pseudonionas sp. did not manifest any dermal lesions. Experiments indicated that among the four EUS-associated test bacteria, A. hydrophila was the most pathogenic, inducing severe dermomuscular necrotic lesions in intramuscularly injected catfish (C. batrachus) and snakeheads (O. striatus). Differences in the susceptibility of O. striatus and C. batrachus to Aquaspirillum sp., Pseudomonas sp. and Streptococcus sp. were evident. Furthermore, this is the first evidence of the association between Aquaspirillum sp. and diseased fish.
    • Article

      Pathogenicity of the epizootic ulcerative syndrome (EUS)-associated rhabdovirus to snakehead Ophicephalus striatus 

      GD Lio-Po, LJ Albright, GS Traxler & EM Leaño - Fish Pathology, 2001 - Japanese Society of Fish Pathology
      The rhabdoviruses isolated from EUS-affected snakeheads in the Philippines was tested for pathogenicity to healthy, naive snakehead Ophicephalus striatus fry, fingerlings and juveniles. Virus exposure of naive snakehead fry and fingerlings by bath at 20-22.5°C resulted in significant mortalities (p<0.01) with no apparent lesions. Naive snakehead juveniles when injected intramuscularly (IM) with the EUS-associated rhabdovirus at ambient water temperature (28-32°C) did not develop any lesion. However, similarly treated snakehead juveniles at 20-22.5°C developed dermal lesions 3-5 days following treatment. The lesions progressed from slight to moderately advanced lesions by days 10-12 but not to deep ulcers as exhibited by naturally EUS-affected snakeheads. Mean mortalities were higher in the virus-injected fish (72%) compared to those in controls (33%). Moreover, the virus was reisolated from fish in the 20-22.5°C treatment but not from fish in the 28-32°C treatment. Virus from infected tissue filtrate and the virus passaged 3 or 4 times induced similar dermal lesions if the rhabdovirus concentration was 103 TCID50/fish or higher. When administered orally, by bath, by intraperitoneal (IP), IM and subdermal injections to snakehead juveniles, only the latter two viral routes induced dermal lesions. However, IP injection of the rhabdovirus caused 75% mortalities but none in control fish. The results demonstrate the pathogenicity of the rhabdovirus isolates to naive snakeheads at low (20-22.5°C) rearing water temperatures.