| Kilham Rat Virus (KRV): It is Parvo virus. It is in 71% of laboratory stock in the USA, 70% in Canada, 60% in UK and and found in 42-60% of wild rats (1) ANTIBODY TEST: Testing for KRV exposure can be done via an ELISA panal. A rat will be sedated at a veterinary hospital and blood will be drawn and sent to a laboratory for results. Positive results mean the rat may have disease now or it has recovered from the disease and still has antibodies to it. It remains detectable in most tissues for 8 weeks, and can be detected in lymphoid tissues for up to 24 weeks post infection (3). Eventually the virus will leave the tissue's of the rat. HOW SPRED: DIRECT contact between rats or their fluids needs to occur for transmission. It is shed in urine, feces, milk and nasal secretions (1). It can be transmitted in utero (2,3). Active disease will occur within 14 days of exposure (1). It can be acquired from the environment the affected rat had contact with - something the affected rat had fluids on. It can remain there for a long time (1,2,3). This is just like Parvo in dogs. That means it can stay in a cage that in not been sterilized. Non affected rats can pick it up from our bodies, bedding, toys and cages. So, sterilize objects with bleach or an antiviral disinfectant. TIME A RAT IS CONTAGEOUS KRV is contageous for a lesser amount of time in adults and a more lengthy time in babies. KRV can be found in the excretions of an affected "ADULT" rat for one to four weeks (3) after exposure. That means it is 'contagious' during that time through urine, feces, pregnant mothers, their milk, and through nasal secretions. It is contagious from a younger rat, born with it or exposed around nursing, for up to 14 weeks (2). UPDATE 2-2004: For athymic rats and some rats that have an abnormal immune systems and cannot overcome viral illnesses, there is belief that this virus can remain in the rat's body and re-occur when the animal is stressed or ill. If you have a rat that often appears ill, remove it from the main colony, and avoid letting it have contact with others. To improve the health of fancy rats, it is recommended to not breed rats that have re-occurent bouts of illness. CONTROL OF DISEASE Quarantine new rats for 14 weeks prior to introducing them to one's colony. This would reduce spred to non infected rats. Sterilize cages at every cleaning and return all cagemates to their same cage to reduce infection from one rat cage to another. Quarintine breeding rats separately one month prior to breeding. It is possible to have KRV positive and negative rats in one's rattery. SYMPTOMS: Clinically, most rats have almost NO symptoms at all (1,2,3). During initial infection, it can cause a drop in litter size via maternal absorption of fetuses and early health problems or death of babies (2). It can cause spontaneous death with no symptoms in adults after infection (1). SUMMARY KRV can be combined with other diseases to run down the effectiveness of the immune system, but alone it is usually not symptomatic (1,2). This virus affects breeding rats for one to three months, depending on the age of the rat when first infected. It is easily spred through rats through direct contact. A rat that had infection and recovered may test positive for antibodies for this virus for up to 1.5 to 6 months. After six months the virus is eliminated from all tissues. PUBLIC PERCEPTION: It appears to be a common disease in wild, laboratory, pet and breeder colonies. It causes the most problems in pregnant and nursing rats and their babies after infection. It can combine with other virus and myco to make a rat ill. It can burn out of a quarantined rattery if sterilization and quarintine measures are implemented. Sources: (1) Infectious Diseases of Mice and Rats (1991) Institute for Laboratory Animal Research (ILAR) Pages 236-239. (2) Laboratory Animals (1999), GV-SOLAS, Working Group on Hygiene. Page SI:55-SI57. (3) Laboratory Animal Science No. 2 (2000) Vol. 27 Page 71-72 By D.Needham Odd Fellows Rattery www.skyclyde.com |
| The KRV Virus in the Hobbyists Rattery by D. Needham Odd Fellows Rattery, Website: www.skyclyde.com This is an overview reprinted from a posting on RatsPacNW. |