Infectivity and pathogenicity of the oomycete Aphanomyces invadans in Atlantic menhaden Brevoortia tyrannus

Yasunari Kiryu, Jeffrey D. Shields, Wolfgang K. Vogelbein, Howard Kator, Vicki S. Blazer

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

Atlantic menhaden Brevoortia tyrannus develop characteristic skin ulcers in response to infection by the oomycete Aphanomyces invadans. To investigate pathogenicity, we conducted a dose response study. Juvenile menhaden were inoculated subcutaneously with 0, 1, 5, 10, 100, and 500 secondary zoospores per fish and monitored for 37 d post-injection (p.i.). Survival rates declined with increasing zoospore dose, with significantly different survivorship curves for the different doses. Moribund and dead fish exhibited characteristic ulcerous lesions at the injection site starting at 13 d p.i. None of the sham-injected control fish (0 zoospore treatment) died. The LD50 (lethal dose killing 50% of exposed menhaden) for inoculated fish was estimated at 9.7 zoospores; however, some fish receiving an estimated single zoospore developed infections that resulted in death. Menhaden were also challenged by aqueous exposure and confirmed that A. invadans was highly pathogenic by this more environmentally realistic route. Fish that were acclimated to culture conditions for 30 d, and presumably free of skin damage, then aqueously exposed to 100 zoospores ml-1, exhibited 14% lesion prevalence with 11% mortality. Net-handled fish that were similarly infected had a significantly higher lesion prevalence (64%) and mortality (64%). Control fish developed no lesions and did not die. Scanning electron microscopy of fish skin indicated that zoospores adhered to intact epidermis, germinated and penetrated the epithelium with a germ tube. Our results indicate that A. invadans is a primary pathogen of menhaden and is able to cause disease at very low zoospore concentrations.

Original languageEnglish (US)
Pages (from-to)135-146
Number of pages12
JournalDiseases of Aquatic Organisms
Volume54
Issue number2
DOIs
StatePublished - Mar 31 2003

Fingerprint

Brevoortia tyrannus
Aphanomyces
infectivity
Oomycetes
zoospores
pathogenicity
menhaden
fish
lesions (animal)
lesion
skin
skin (animal)
survival rate
fish nets
injection
germ tube
injection site
mortality
epidermis (animal)
lethal dose

All Science Journal Classification (ASJC) codes

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science

Cite this

Kiryu, Yasunari ; Shields, Jeffrey D. ; Vogelbein, Wolfgang K. ; Kator, Howard ; Blazer, Vicki S. / Infectivity and pathogenicity of the oomycete Aphanomyces invadans in Atlantic menhaden Brevoortia tyrannus. In: Diseases of Aquatic Organisms. 2003 ; Vol. 54, No. 2. pp. 135-146.
@article{9d8c4d60fcc343a1b061a66d1110957d,
title = "Infectivity and pathogenicity of the oomycete Aphanomyces invadans in Atlantic menhaden Brevoortia tyrannus",
abstract = "Atlantic menhaden Brevoortia tyrannus develop characteristic skin ulcers in response to infection by the oomycete Aphanomyces invadans. To investigate pathogenicity, we conducted a dose response study. Juvenile menhaden were inoculated subcutaneously with 0, 1, 5, 10, 100, and 500 secondary zoospores per fish and monitored for 37 d post-injection (p.i.). Survival rates declined with increasing zoospore dose, with significantly different survivorship curves for the different doses. Moribund and dead fish exhibited characteristic ulcerous lesions at the injection site starting at 13 d p.i. None of the sham-injected control fish (0 zoospore treatment) died. The LD50 (lethal dose killing 50{\%} of exposed menhaden) for inoculated fish was estimated at 9.7 zoospores; however, some fish receiving an estimated single zoospore developed infections that resulted in death. Menhaden were also challenged by aqueous exposure and confirmed that A. invadans was highly pathogenic by this more environmentally realistic route. Fish that were acclimated to culture conditions for 30 d, and presumably free of skin damage, then aqueously exposed to 100 zoospores ml-1, exhibited 14{\%} lesion prevalence with 11{\%} mortality. Net-handled fish that were similarly infected had a significantly higher lesion prevalence (64{\%}) and mortality (64{\%}). Control fish developed no lesions and did not die. Scanning electron microscopy of fish skin indicated that zoospores adhered to intact epidermis, germinated and penetrated the epithelium with a germ tube. Our results indicate that A. invadans is a primary pathogen of menhaden and is able to cause disease at very low zoospore concentrations.",
author = "Yasunari Kiryu and Shields, {Jeffrey D.} and Vogelbein, {Wolfgang K.} and Howard Kator and Blazer, {Vicki S.}",
year = "2003",
month = "3",
day = "31",
doi = "10.3354/dao054135",
language = "English (US)",
volume = "54",
pages = "135--146",
journal = "Diseases of Aquatic Organisms",
issn = "0177-5103",
publisher = "Inter-Research",
number = "2",

}

Infectivity and pathogenicity of the oomycete Aphanomyces invadans in Atlantic menhaden Brevoortia tyrannus. / Kiryu, Yasunari; Shields, Jeffrey D.; Vogelbein, Wolfgang K.; Kator, Howard; Blazer, Vicki S.

In: Diseases of Aquatic Organisms, Vol. 54, No. 2, 31.03.2003, p. 135-146.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Infectivity and pathogenicity of the oomycete Aphanomyces invadans in Atlantic menhaden Brevoortia tyrannus

AU - Kiryu, Yasunari

AU - Shields, Jeffrey D.

AU - Vogelbein, Wolfgang K.

AU - Kator, Howard

AU - Blazer, Vicki S.

PY - 2003/3/31

Y1 - 2003/3/31

N2 - Atlantic menhaden Brevoortia tyrannus develop characteristic skin ulcers in response to infection by the oomycete Aphanomyces invadans. To investigate pathogenicity, we conducted a dose response study. Juvenile menhaden were inoculated subcutaneously with 0, 1, 5, 10, 100, and 500 secondary zoospores per fish and monitored for 37 d post-injection (p.i.). Survival rates declined with increasing zoospore dose, with significantly different survivorship curves for the different doses. Moribund and dead fish exhibited characteristic ulcerous lesions at the injection site starting at 13 d p.i. None of the sham-injected control fish (0 zoospore treatment) died. The LD50 (lethal dose killing 50% of exposed menhaden) for inoculated fish was estimated at 9.7 zoospores; however, some fish receiving an estimated single zoospore developed infections that resulted in death. Menhaden were also challenged by aqueous exposure and confirmed that A. invadans was highly pathogenic by this more environmentally realistic route. Fish that were acclimated to culture conditions for 30 d, and presumably free of skin damage, then aqueously exposed to 100 zoospores ml-1, exhibited 14% lesion prevalence with 11% mortality. Net-handled fish that were similarly infected had a significantly higher lesion prevalence (64%) and mortality (64%). Control fish developed no lesions and did not die. Scanning electron microscopy of fish skin indicated that zoospores adhered to intact epidermis, germinated and penetrated the epithelium with a germ tube. Our results indicate that A. invadans is a primary pathogen of menhaden and is able to cause disease at very low zoospore concentrations.

AB - Atlantic menhaden Brevoortia tyrannus develop characteristic skin ulcers in response to infection by the oomycete Aphanomyces invadans. To investigate pathogenicity, we conducted a dose response study. Juvenile menhaden were inoculated subcutaneously with 0, 1, 5, 10, 100, and 500 secondary zoospores per fish and monitored for 37 d post-injection (p.i.). Survival rates declined with increasing zoospore dose, with significantly different survivorship curves for the different doses. Moribund and dead fish exhibited characteristic ulcerous lesions at the injection site starting at 13 d p.i. None of the sham-injected control fish (0 zoospore treatment) died. The LD50 (lethal dose killing 50% of exposed menhaden) for inoculated fish was estimated at 9.7 zoospores; however, some fish receiving an estimated single zoospore developed infections that resulted in death. Menhaden were also challenged by aqueous exposure and confirmed that A. invadans was highly pathogenic by this more environmentally realistic route. Fish that were acclimated to culture conditions for 30 d, and presumably free of skin damage, then aqueously exposed to 100 zoospores ml-1, exhibited 14% lesion prevalence with 11% mortality. Net-handled fish that were similarly infected had a significantly higher lesion prevalence (64%) and mortality (64%). Control fish developed no lesions and did not die. Scanning electron microscopy of fish skin indicated that zoospores adhered to intact epidermis, germinated and penetrated the epithelium with a germ tube. Our results indicate that A. invadans is a primary pathogen of menhaden and is able to cause disease at very low zoospore concentrations.

UR - http://www.scopus.com/inward/record.url?scp=0037475116&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0037475116&partnerID=8YFLogxK

U2 - 10.3354/dao054135

DO - 10.3354/dao054135

M3 - Article

C2 - 12747639

AN - SCOPUS:0037475116

VL - 54

SP - 135

EP - 146

JO - Diseases of Aquatic Organisms

JF - Diseases of Aquatic Organisms

SN - 0177-5103

IS - 2

ER -