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Disease Treatment. Methods of Disease Control in Fish. Test and Slaughter Quarantine or restrict movements Destruction of transmission link Immunity/disease resistance Drug therapy.
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Methods of Disease Control in Fish • Test and Slaughter • Quarantine or restrict movements • Destruction of transmission link • Immunity/disease resistance • Drug therapy
Drug/chemotherapeutics are small part of any health management plan- May increase carrying capacity- May be detrimental Types- Systemic- Topical- Disease prophylaxis- Injections- Disinfectants Types of Drug Therapies
Laws governing Drug use • Federal food drug and cosmetic act of 1915- Limits use of most substances till safety to animals is proved • Three Criteria for approval 1. Examined for effectiveness2. Toxicity of Compound3. Time of clearance of compound or metabolites • The Revised act of 1965 included food additives
Drug Regulation • Food and drug Administration is responsible for regulating drugs and chemotherapeutics • Three levels of drugs1. Approved 2. Low Regulatory Priority3. INAD (Investigation New Animal Drug)
Good Management Practices • Avoid/Limit disease occurrencetreat on a population basis • Questions to consider1. What is the prognosis without treatment?2. Does potential mortality warrant treatment? • Four criteria to know1. Water2. Fish3. Chemical4. Disease
External Treatments • Success is a balance of time in treatment and concentration of treatment • Treatments are used to eliminate /reduce potential pathogens • Also used as a tool for maintenance of fish health- Bactericides, fungicides, parasides
Types of External Treatments • Dip • Flush • Bath • Flow through • Pro’s/Cons of Different approaches?- Handling aspect, mucous is primary line of defense- Concentration of treatment- Stress factors related to treatment
Systemic Treatment • Administered in an oral route, sometimes parentally (BKD) • An effective treatment must be able to control reproduction of the pathogen as well as safe and economical • Limitations:Mixing Consistent feedingEach fish gets required amountsProphylaxis (Not recommended)
Considerations with treatments • Withdrawal Time- Drug- Fish Species- Water Temperature
Wt. or volume of water 100 ------------ % activity Wt. or volume of chem./drug Desired concentration x x = 100 --------------- % activity Treatment level (mg/kg/day) Wt. of drug needed Wt. of fish x x = Static Treatments Constant-Flow Treatments Flow rate (l/min) x Treatment time (min) x final concentration (ppm) x .001 Chemical strength (decimal fraction) Wt. of chem./drug needed = Amount of drug to feed