ISSN:
1365-2761
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
,
Medicine
Notes:
Abstract. Brook trout, Salvelinus fontinalis Mitchell, fry were divided into eight age groups of 1–8 weeks post-hatch (wph) and immunized by a single direct immersion in formalin-inactivated infectious pancreatic necrosis virus (ipnv). After a direct-immersion ipnv challenge given 4 weeks later, only fry immunized at 2, 3 and 6wph showed protection. The relative per cent survival 60 days after ipnv challenge was highest in 2 and 3 wph fry (45–50%) and decreased as fish increased in age or size. The same response was obtained one year later when four age groups of fry, from 1 to 4wph, were immunized with a different serotype and dose of ipnv. The 2 and 3 wph fry had mean weights between 49 and 60mg at immunization. Killed vaccines administered by immersion have not previously been reported as inducing protection in salmonid fry of such low weights. Analysis of the growth of the fry suggests that protection against IPNV requires immunization in the eleutheroembryo phase, during the time of slow weight gain. This appears to be in direct contrast to the stage of ontogeny and weight growth rate required for successful immunization against the bacterial pathogen Vibrio anguillarum. Although immunization with two ipnv serotypes reduced mortalities from challenges with these same virus isolates, it did not prevent ipnv infection of fry in any age group.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2761.1990.tb00764.x
