SHRIMP VIRUS IN CENTRAL AMERICA
Date: 24 February 1999
To: AQUA-L@killick.ifmt.nf.ca
QUESTION
Besides the confirmation from Don Lightner about the presence of white spot and yellow head in Honduras, I have been hearing lots of noise about it being in the South of Mexico, Nicaragua and Costa Rica. Does anybody have info on the propagation of these viruses?
Attilio E. Castano
e-mail: acastano@ecua.net.ec>
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COMMENTS 1:
WSSV has been documented in South Carolina since 1997. Outbreaks occurred on a farm in 1997 and 1998. In 1998 it spread to a second nearby farm. This is in contrast to TSV which quickly spread to many farms during a 1996 outbreak. There is some preliminary laboratory evidence to suggest that WSSV may not survive outside of host tissue as long as TSV. On the other hand, the host range for WSSV is much broader and it can be carried by many different taxa of crustaceans.
Clearly, information on factors which may affect virulence and the probability of getting an acute outbreak in a pond will be crucial for controlling reinfection once the disease is established in local crustaceans. In our experience, once there is an acute outbreak of WSSV in L. vannamei or L. stylirostris, it quickly spreads within a farm and mortality rates approach 100%. Although the virus has been tentatively identified in local crustaceans, not all farms have been affected. It is my understanding that by carefully screening PL, controlling crustacean vectors, improving overall husbandry and limiting water exchange, the disease has been brought under control in some areas.
Issues related to the spread of these agents and factors affecting the probability of reinfection are important topics for discussion and I hope that we can get more input from our colleagues in Asia on these matters.
Craig L. Browdy
South Carolina Department of Natural Resources
Waddell Mariculture Center
POB 809
Bluffton, SC 29910 USA
Phone 843-837-3795
Fax 843-837-3487
e-mail: browdycl@musc.edu
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COMMENTS 2:
According to my notes taken at Dr. Lightner's class, the white spot baculovirus (WSSV) has been detected in Macrobrachium. I have no record if it was pathogenic to them.
In 1997 WSSV was detected and reported infecting and causing death in freshwater crayfish (Orconectes and Procambarus spp) used at the National Zoo for feeding cephalopods (see 1997 Proceedings of the American Assoc of Zoo Veterinarians).
I have no information as to the infectivity or pathogenicity of the yellow head virus to Macrobrachium.
Kent Hauck
Fish Pathologist
e-mail: agmain.khauck@state.ut.us
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COMMENTS 3:
At its greatly expanded web page, The Global Aquaculture Alliance, a trade organization for fish and shellfish farms, has posted a news release on the recent discovery of shrimp whitespot virus in Central America. Dr. Darryl Jory---the new editor of GAA's newsletter, "The Advocate"---prepared the release. It names the countries in Central America where whitespot has been confirmed, provides a brief history of the virus, and suggests management strategies for dealing with it.
You can view the full text of the release at http://www.gaalliance.org, which will become a clearing house of information on whitespot in the Americas!
The site also contains background information on GAA and all the back issues of "The Advocate", which are loaded with aquaculture industry news.
Bob Rosenberry, Editor/Publisher
Shrimp News International
9450 Mira Mesa Boulevard, Suite B-562
San Diego, California 92126 USA
Phone 619-271-6354
Fax 619-271-0324
e-mail: Shrimpnews@aol.com
Web Page http://members.aol.com/brosenberr/Home.html
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