Should we use a heat cycle during quarantine to combat KHV

[Brutuscz]

Blackwater is a "closed" facility. Koi only go out...new koi never come in. They are all bred from existing stock. A smart way to go if you ask me. Better than risking KHV and losing your whole business.

I think that was blue ridge that got wiped out..had SVC, Heard they are clean now.

[bekko]

Mulberry, I cannot find the "Referral Veterinarians" link. Do you know where they moved it?

Thanks,
steve hopkins

[dinh]

I think this is very helpful, specially for the newbie. Thanks for the info MJen!!



--Dinh

Quote: Originally Posted by mulberryjen OK, this is a bit long, but detailed and informative. Information obtained from http://www.barsons.com/khv.htm and http://edis.ifas.ufl.edu/VM113 (Univ. of Florida) sites. Jen SYSTEM REQUIREMENTS Quarantine is forced isolation. Therefore, a suitable place for this isolation needs to be prepared. Excellent conditions and good water quality is essential because no quarantine is better than quarantine in a system that has poor conditions. Details of how to build several different quarantine systems will be given in the May/June '03 issue of KoiUSA. The quarantine system needs to: Be adequate in size and shape - round is better than square Be free of initial pathogens - sanitize the system prior to use, or use a system known to be disease free. Be in a safe place - the environment should be tranquil and not subject to extremes Have a working bio filter - nearly a must and a definite advantage - otherwise daily water changes and ammonia binders are required. Have the capacity to heat the water to 70-75 degrees F. Be located a sufficient distance or have barriers such that other areas are not easily contaminated by water or equipment used in and/or around the system. Have adequate disinfection - see separate disinfection section. If the 'heat method' is intended to be employed in an attempt to increase survivors of KHV, provisions to heat the tank water to 86 F need to be available. THE PROTOCOL Under ideal conditions, the water in the quarantine tank should be the same temperature and pH as the wat4er in which the koi has been swimming over the last couple of weeks. If this is not possible, then try to get as close to the temperature as practical, remembering that koi tolerate a rise in water temperature better than a drop. The koi to be isolated should be contained in a transport bag with adequate water and oxygen and floated in the isolation tank water for 20 to 30 minutes to allow for temperature equilibrium between the water in the bag and in the tank. Fish (but not transport water) should be released into a properly sized container (koi tub) of clean quarantine tank water and subsequently the fish should be quickly transferred to the tank. If the hobbyist is not competent to handle the fish with bare hands, the transport bag should be used to transfer the koi and should contain as little water as possible, the goal being to minimize the amount of transport water put into the quarantine tank. The fish should be kept quiet and under cover of Styrofoam or pvc pipes The temperature of the water in the Q-tank should be adjusted and held between 70 to 75 F for a period of no less than three weeks. During the temperature adjustment period, the temperature should not drop or raise more than 5F per day. Do not feed the koi for the first few days. Then, if the fish appear hungry, start feeding a little twice per day. Over the entire period of quarantine, be sure to monitor water parameters, particularly ammonia, nitrite, pH alkalinity, and temperature and make any necessary adjustments and/or take appropriate measures. Water changes are usually beneficial, are recommended and a minimum of 10% per day is advisable. Always dechlorinate new water used for water changes and use an ammonia binder if the water contains chloramines and you are changing over 20% or if you do not have a working bio-converter on the system. The fish should be maintained at 70-75 F for no less than three weeks and a much better period would be three months. The longer the quarantine period, the more likely infected fish will be revealed. At some time during the quarantine period, a fish of "lesser desirability" from your pond should be placed in the tank with the new arrival(s). Koi are social animals, and need companions. However, if there are more than one koi in quarantine, the pond fish can be added after 1-3 weeks in quarantine, and the population kept for 3 weeks to 3 months more. By waiting until 3 weeks, many diseases, including KHV will become obvious, and can be eliminated before any pond fish are at risk. During the period of quarantine, periodically check (or have a professional check) for any other abnormal or disease conditions. It is advisable to have a complete and accurate diagnosis of conditions found in quarantine, make sure that the quarantine system has good water quality and follow expert advice for keeping koi healthy. Monitor the tank daily and if any fish (new or old) shows the symptoms typical of KHV, call a qualified veterinarian to take samples and submit them to a qualified lab for testing. For a list of qualified veterinarians, see the AKCA web site at: www.akca.org and follow the "KHA" link then the "Referral Veterinarians" link. If maintained at the 70-75 F temperature with no attempt to otherwise support the fish or suppress opportunistic pathogens, about 10% of the fish should be expected to survive. KHV infected koi may be euthanized (humanely killed) and disposed of properly to prevent spread, or an attempt may be made to save the fish. One method reported successful in saving a substantial percentage of KHV infected koi is to elevate the temperature of the tank water to 86 F until the fish recovers. Others (see previous section) involve adding chemicals to the water to treat the symptoms of sick fish and possibly to prevent transmission of virus. Remember there is no cure for KHV. KHV disease may cause 80-100% mortality in affected populations, and fish seem most susceptible at water temperatures of 72-81°F (22-27°C) (OATA, 2001). This viral disease affects fish of various ages, but cohabitation studies show that fry have a greater susceptibility than mature fish (Perelberg et al., 2003). How Does Water Temperature Affect KHV Disease? The virus appears to have an incubation period of 14 days following the introduction of infected fish to naïve fish (fish that have not been exposed before) (OATA, 2001; Ronen et al., 2003). However, incubation may be longer, indicating that appropriate temperature and possibly a second trigger may be necessary for outbreaks to occur. Mortality related to KHV disease typically occurs between 64°F and 81°F (18-27°C). Almost no mortalities occur below 64°F, and there has been no reported occurrence of the disease at or above 86°F (30°C) (OATA, 2001; Goodwin, 2003).There is no known treatment for KHV. Antiviral drugs are not currently available to treat KHV or any other viral diseases of cultured fish. Studies have shown that fish may develop a natural resistance following viral exposure if water temperatures are increased to 86°F (30°C) (Ronen et al., 2003). However, this technique only marginally increases survival rates and artificially raising water temperatures in holding facilities above 80°F may result in an increased occurrence of other more common bacterial and parasitic diseases. High water temperatures are not generally recommended for routine husbandry and management of koi and common carp.