Experimental Infection and Pathogenesis of Viral Erythrocytic Necrosis (VEN) in Atlantic Cod, Gadus morhua

1986 ◽  
Vol 43 (5) ◽  
pp. 945-951 ◽  
Author(s):  
Paul W. Reno ◽  
Katherine Kleftis ◽  
Stuart W. Sherburne ◽  
Bruce L. Nicholson

Mature Atlantic cod (Gadus morhua) were experimentally infected with viral erythrocytic necrosis (VEN) by inoculation with washed erythrocytes or ceil-free homogenates of erythrocytes from naturally infected fish. Approximately one third of the animals exposed exhibited active infections. The temporal pattern of infection was similar between naturally infected and experimentally infected fish. One to two months after infection, immature erythrocytes began to show clear evidence of VEN followed by a rapid increase in the proportion of infected immature erythrocytes, frequently reaching 100%. A subsequent dramatic drop in infection of immature erythrocytes occurred, coinciding with an increase of infection in mature erythrocytes. Significant erythroblastosis occurred when the overall erythrocyte infection rate reached approximately 10%, but none of the newly generated erythrocytes appeared infected. The peak infection rate (40–60% of erythrocytes infected) declined slowly and the infection, in most instances, was completely resolved.

1972 ◽  
Vol 50 (7) ◽  
pp. 1051-1054 ◽  
Author(s):  
R. A. Khan

Trypanosomes were found in 145 (24%) of 610 Atlantic cod, Gadus morhua L., following examination of centrifuged blood samples. The smallest infected fish measured 26 cm. Generally, parasitemias were higher in cod 26–35 cm long than in larger fish, but were more prevalent among fish 56–70 cm. The parasite could not be transmitted experimentally to Pseudopleuronectes americanus, Myoxocephalus octodecemspinosus, M. scorpius, Tautogolabrus adspersus, or Limanda ferruginea, but uninfected cod were susceptible. The trypanosome appears distinct from Trypanosoma coelorhynchi Laird, 1951 from gadiform fishes in New Zealand waters. It is tentatively identified as T. murmanensis Nikitin, 1927 reported from the same host, G. morhua, captured at Murmansk, U.S.S.R.


1985 ◽  
Vol 63 (9) ◽  
pp. 2141-2144 ◽  
Author(s):  
R. A. Khan

The susceptibility of four species of marine fish (Gadus morhua, Pseudopleuronectes americanus, Myoxocephalus scorpius, and Myoxocephalus octodecemspinosus) to leech-transmitted Trypanosoma murmanensis was assessed 49–60 days after infection by comparing condition factor, organ somatic indices, parasitological, hematological, and histological findings with corresponding uninfected animals. The fish were maintained at temperatures (0–1 °C) to simulate the environment where transmission occurs naturally. High mortality occurred in juvenile Atlantic cod and winter flounder, but deaths decreased with increasing fish size. No adult fish died except flounder when fin rot was present. Anemia was the most common pathological feature observed in young fish at necropsy, but its severity was not always correlated with the level of parasitemia. The persistent anemia was probably associated with an inactive rather than an impaired hemopoietic system. Condition factor and somatic indices of liver, spleen, and heart were altered in some infected fish groups. It is concluded that T. murmanensis is a potential pathogen, especially to juvenile American plaice, Hippoglossoides platessoides, in which high prevalences of natural infections have been observed in some areas of the northwestern Atlantic Ocean.


2014 ◽  
Vol 514 ◽  
pp. 217-229 ◽  
Author(s):  
HY Wang ◽  
LW Botsford ◽  
JW White ◽  
MJ Fogarty ◽  
F Juanes ◽  
...  

2009 ◽  
Vol 36 (4) ◽  
pp. 883-891 ◽  
Author(s):  
Carlo C. Lazado ◽  
Christopher Marlowe A. Caipang ◽  
Sanchala Gallage ◽  
Monica F. Brinchmann ◽  
Viswanath Kiron

Author(s):  
Sayyed Mohammad Hadi Alavi ◽  
Azadeh Hatef ◽  
Ian A.E. Butts ◽  
Olga Bondarenko ◽  
Jacky Cosson ◽  
...  

2000 ◽  
Vol 57 (4) ◽  
pp. 826-836 ◽  
Author(s):  
Jean-Denis Dutil ◽  
Yvan Lambert

The extent of energy depletion was assessed in Atlantic cod (Gadus morhua) in spring and early summer (1993-1995) to assess relationships between poor condition and natural mortality. Several indices of condition were compared in wild fish in the northern Gulf of St. Lawrence and in fish exposed to a prolonged period of starvation in laboratory experiments. Discriminant analyses classified only a small fraction of the wild fish as similar to cod that did not survive and a much larger fraction as similar to cod that survived starvation. This percentage increased from April to May and peaked in June 1993 and 1994. Condition factor and muscle somatic index allowed a clear distinction between live and dead fish. Muscle lactate dehydrogenase activity suggested that cod had experienced a period of negative growth early in 1993, 1994, and 1995. Fish classified as similar to starved individuals were characterized by a higher gonad to liver mass ratio than others. Reproduction may have a negative impact on survival not only in spring but also later into summer, as some individuals were found not to have recovered by late summer. This study shows that natural mortality from poor condition contributed to lower production in the early 1990s.


2018 ◽  
Vol 18 (1) ◽  
Author(s):  
Andrea Bagi ◽  
Even Sannes Riiser ◽  
Hilde Steine Molland ◽  
Bastiaan Star ◽  
Thomas H. A. Haverkamp ◽  
...  

2010 ◽  
Vol 70 (5) ◽  
pp. 383-394 ◽  
Author(s):  
Sonnich Meier ◽  
H. Craig Morton ◽  
Gunnar Nyhammer ◽  
Bjørn Einar Grøsvik ◽  
Valeri Makhotin ◽  
...  

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