<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>J. D. Shields</dc:contributor>
  <dc:contributor>W. K. Vogelbein</dc:contributor>
  <dc:contributor>H. Kator</dc:contributor>
  <dc:contributor>V. S. Blazer</dc:contributor>
  <dc:creator>Y. Kiryu</dc:creator>
  <dc:date>2003</dc:date>
  <dc:description>&lt;p&gt;Atlantic&lt;span&gt;&amp;nbsp;&lt;/span&gt;menhaden&lt;span&gt;&amp;nbsp;&lt;/span&gt;Brevoortia&lt;span&gt;&amp;nbsp;&lt;/span&gt;tyrannus&lt;span&gt;&amp;nbsp;develop characteristic skin ulcers&amp;nbsp;&lt;/span&gt;in&lt;span&gt;&amp;nbsp;response to infection by the&amp;nbsp;&lt;/span&gt;oomycete&lt;span&gt;&amp;nbsp;&lt;/span&gt;Aphanomyces&lt;span&gt;&amp;nbsp;&lt;/span&gt;invadans&lt;span&gt;. To investigate&amp;nbsp;&lt;/span&gt;pathogenicity&lt;span&gt;, we conducted a dose response study. Juvenile&amp;nbsp;&lt;/span&gt;menhaden&lt;span&gt;&amp;nbsp;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 LD&lt;/span&gt;&lt;sub&gt;50&lt;/sub&gt;&lt;span&gt;&amp;nbsp;(lethal dose killing 50% of exposed&amp;nbsp;&lt;/span&gt;menhaden&lt;span&gt;) for inoculated fish was estimated at 9.7 zoospores; however, some fish receiving an estimated single zoospore developed infections that resulted&amp;nbsp;&lt;/span&gt;in&lt;span&gt;&amp;nbsp;death.&amp;nbsp;&lt;/span&gt;Menhaden&lt;span&gt;&amp;nbsp;were also challenged by aqueous exposure and confirmed that A.&amp;nbsp;&lt;/span&gt;invadans&lt;span&gt;&amp;nbsp;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&lt;/span&gt;&lt;sup&gt;-1&lt;/sup&gt;&lt;span&gt;, 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.&amp;nbsp;&lt;/span&gt;invadans&lt;span&gt;&amp;nbsp;is a primary pathogen of&amp;nbsp;&lt;/span&gt;menhaden&lt;span&gt;&amp;nbsp;and is able to cause disease at very low zoospore concentrations.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.3354/dao054135</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Inter-Research</dc:publisher>
  <dc:title>Infectivity and pathogenicity of the oomycete Aphanomyces invadans in Atlantic menhaden Brevoortia tyrannus</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>