PATHOGEN CLASSIFICATION SCHEME

The scheme is based on the nature of the pathogen, available literature on distribution and known effects on wild and cultured stocks, and existing distribution within the waters of the State of Maryland. Specific points used in developing this scheme were:

1. Known pathogenicity and virulence of the organism in question.
2. Species susceptibility.
3. Source of fish or fish products.
4. Geographical considerations both intercontinental and continental.
5. Availability of gray and peer reviewed literature on source region or species to be imported.

The scheme also takes into consideration the following:

1. That immunological and genetic naivete to a specific pathogen constitutes reason for avoidance.
2. That the Continental Divide of North America constitutes a significant barrier dividing the United States into two geographical zones.
3. That specific countries or watersheds within countries possess unique pathogens that could pose significant threats to wild and cultured stocks of fish.
4. That, in most instances, the source country has little or no information on the pathogens present in wild stocks.

The scheme is as follows:

PRIORITY ONE -- ABSOLUTE AVOIDANCE

1. Mandatory screening of individual lots.
2. Detection in fish screened constitutes cause for denial of acceptance.
3. If special methods required, they must be applied for specific pathogens.
4. When detected, must be reported to Maryland officials.

PRIORITY TWO -- AVOIDANCE DESIRED, ACHIEVED VIA RISK MINIMIZATION

1. Mandatory screening of individual lots.
2. Detection in fish screened constitutes cause for denial of acceptance if
   1. clinical signs are associated with the detection, and
   2. detection rate exceeds either 10% of all individuals examined or 50% of known infection rate in wild or cultured stocks of the destination waters.
3. Special methods not required.
4. When detected, must be reported to Maryland officials.

1. Mandatory screening of individual lots.
2. Detection in fish screened does not constitute cause for denial of acceptance, however, transport of fish showing clinical signs is discouraged.
3. Special methods not required.
4. When detected, must be reported to Maryland officials.

PRIORITY FOUR -- SPECIAL CASES

1. Mandatory screening of individual lots when:
   1. the pathogen is present in a region and is known to threaten wild or cultured stocks
   2. information on the disease and associated causes is unavailable from the country or region serving as the source.
2. Detection of the pathogen in fish screened may constitute cause for denial of acceptance or require special holding conditions.
3. If special methods are required, they must be applied for the specific pathogen.
4. When detected, must be reported to Maryland officials.

All other pathogens not on this list are nonreportable to Maryland officials, however, it is desirable that they be part of the management records. Fish showing clinical signs of any disease or parasite should be avoided. Importation of diseased fish can have a direct negative impact on the reputation of a facility, and future marketing by the exporting facility. Pathogens will be added or deleted as circumstances and knowledge warrant.