1	Diseases Yolanda J. Brady, Ph. D. Associate Professor Auburn University Dept. of Fisheries and Allied Aquacultures 209 Swingle Hall Auburn University, AL 36849-5419 334-844-9122 bradyyj@auburn.edu
2	Diseases are caused by: Infectious agents Parasites Bacteria Fungi Viruses
3	Diseases are caused by: Non-infectious agents Nutritional Low oxygen levels- hypoxia Intoxication- toxins,algae, fungal Neoplasia- cancer
4	Definitions Disease: deviation from health
5	Definitions bacteremia- the presence of living bacteria in the blood with or without significant response on the part of the host.
6	Definitions septicemia- a clinical syndrome characterized by severe bacteremia infection, generally involving the significant invasion of the blood stream by microorganisms
7	DISEASE TRANSMISSION Vertical Parent (within or on egg/sperm) [ Offspring Horizontal Fish---Fish=== Fish
8	SIGNS OF DISEASE 1. Fish do not feed 2. Erratic swimming or lethargic swimming
9	SIGNS OF DISEASE 3. Excessive mucous production
10	SIGNS OF DISEASE 4. Fluid filled body cavity- ascites
11	SIGNS OF DISEASE 5. Necrosis- dead tissue within a living animal
12	SIGNS OF DISEASE 6. Eroded or frayed fins
13	SIGNS OF DISEASE 7. Swollen kidney, liver, inflamed internal organs
14	SIGNS OF DISEASE 8. Fluid accumulation behind the eye - exopthalmia
15	SIGNS OF DISEASE 9. Hemorrhage
16	SIGNS OF DISEASE
17	Types of communicable diseases 1. Obligate pathogen - is normally absent in water. These organisms do not survive or multiply in nature indefinitely unless a diseased or carrier fish is present. Parasites (true) Cryptocaryon irritans Viral diseases Some bacteria
18	Types of communicable diseases 2. Facultative pathogen (non-obligate) Normally present in the environment and may cause a disease in susceptible species. Aeromonas hydrophila- motile aeromonas septicemia Vibrio spp.-vibriosis
19	Health Management Stocking and Handling of Fish Careful handling during transport Prophylactic treatment Temperature Crowding Feed Management Good quality feed Storage Water Flow Aeration
20	Disease Control and Hatchery Management Minimizing stress on cultured fish Prevention of the introduction of serious diseases Confinement of disease outbreaks Minimizing losses from disease outbreaks Learning from past disease outbreaks to minimize future disease losses
21	FACTORS IN DISEASE DEVELOPMENT Source of infection Method of transmission Portal of entry Virulence of the organism Resistance of the host
22	Diseases of Marine Fish
23	Microbes Virus Lymphocystis Bacteria Mycobacterium spp. Vibrio spp. Streptococcus Aeromonas spp. Fungi Aphanomyces spp.
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25	Bacteria cause disease by: Produce exotoxins- gram positive bacteria Release endotoxins- gram negative bacteria Release proteolytic enzymes Physical impairment of circulatory system
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30	Selective media TCBS- thiosulfate citrate bile salts sucrose Selects for Vibrio species
31	Vibrios involved in fish diseases Vibrio anquillarum V. ordalii V. salmonicida
32	Vibrios in foodborne disease V. alginloyticus V. damsella V. mimicus V. parahaemolyticus V. cholerae 01 V. cholerae non-01 V. vulnificus
33	V. cholerae 01 Isolated in the Gulf of Mexico waters, presumed to be from ships off-loading contaminated ballast water. July 2, 1991, FDA isolated V. cholerae 01 from oysters and intestinal contents of an oyster eating fish in Mobile Bay. No cholera have been attributed to fish or shellfish harvested from US waters.
34	Vibrio cholerae non-01 Less severe form of cholera, gastroenteritis Often found in raw or improperly cooked oysters in US coastal waters.
35	Vibrio parahaemolyticus Frequently isolated from estuarine and marine environments in US. Pathogenic and non-pathogenic forms exist. Infections occur from consumption or raw or improperly cooked shellfish
36	Vibrio vulnificus Causes infections and death from wound infections and consumption of raw molluscan shellfish Primary septicemia May cause disease in healthy individuals
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40	Parasites
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49	Oyster Diseases
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51	Treatment/Control Sanitary conditions Good water quality Filtration UV sterilization
52	Perkinsus marinus- “dermo” Clinical Signs: Oysters exhibit slow growth, often emaciated meat, discolored by melanin pigment. Warm season disease, requires 20^oC and proliferates rapidly at temperatures greater than 25^oC.
53	“dermo” Pathogen spreads through oyster tissues via blood sinuses and gradually destroys tissues and blocks organ functions. Parasite overwhelms host by rapid proliferation of cells. Usually seen in larger oysters due to large volume of water filtered. During warm weather in late summer and early fall, "dermo" greatly increases in number and intensity of infections and deaths.
54	"Incubate tissues in fluid thioglycollate..." Incubate tissues in fluid thioglycollate medium with dextrose for one week at 25 to 30 ^oC in the dark. Stain tissues with Lugol's iodine, look for blue-black cysts in tissues.
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59	Perkinsus marinus “dermo”
60	Black Drum
61	Blue Crab
62	Stone Crab
63	Oyster Drill
64	Fouling organisms-barnacles
65	Fouling organisms- mussels
66	Shrimp Diseases
67	Viral Diseases IHHN- Infectious hypodermal and hematopoietic necrosis TSV- Taura Syndrome Virus WSSV- White Spot Syndrome virus YHV - Yellow Head Virus
68	IHHN Infectious hypodermal and hematopoietic necrosis Species affected: Litopenaeus stylirostris, L. vannamei, L. monodon Clinical signs: reduction in food consumption followed by changes in behavior and appearance. Observed to rise slowly in water then sink ventral side up. When they sink to the bottom, usually will have a mottled appearance, then become bluish in color
69	TSV Taura Syndrome Virus Named for the Taura River near Guyaquil, Ecuador where the disease was first reported. First thought to be problem in 1992, but Samples sent to Don Lightner’s lab in Sept. 1991 revealed presence of disease. Occurs in Small juveniles 0.05 g to less than 5 g. Larger shrimp may be affected
70	YHS Yellow Head Syndrome Virus Juvenile to sub-adult (especially during 50-70 day grow-out) in intensive pond culture show an abrupt abnormal increase in feeding rate for several days. Then, cease feeding within a day. Swim slowly near the edge of pond. Characteristic light yellow cephalothorax. White or pale yellow to brown gills. Pale yellow cephalothorax.
71	WSSV White Spot Syndrome Thought that at least 3 viruses are part of this syndrome. First discovered in early 1990’s, in China, Japan, Korea, Thailand, Indonesia, Taiwan. Also described in Texas. Nearby shrimp processing plant was suspected.
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73	Shell disease Black spot disease Clinical Signs: Brownish to black single or multiple eroded areas on body cuticle, appendages or gills