A soiled bedding sentinel system with rack sentinels and mom sentinels is described. Rack sentinels get soiled bedding from the other cages in the rack. the room sentinels get soiled bedding from the rack sentinels Only room sentinels are regularlytested. The method is economically effective and labor saving and has on two occasions proved efficient when mouse corona virus has appeared in an animal depanment at the Karolinska Institute

Hedenqvist, Patricia

Iwarsson, Krister

Waller, Tage

English

Journals from University of Tartu

Scand. 1‘ Lab. Amm. Sc: No 3 1997 Val 24An extended soiled bedding sentinel system.by Tag? Waller. Pamela lledenqvisl. & Krister lwarsson.Laboratory Animal Unit, Karolinska Institutm, 171 77 StockholmCorrcspondence: T. Waller~ Laboratory Anlma] Umt. Kurolinska Inst1tute. 3-17177 Stockholm SwedenIntroductionHistorlcally. corona virus, mycoplasms, pinwormsand fur mites have been discovered in mice andrats in some of the animal dcparlmcms at theKarolinsku Institute (Iwarsson 1990), These; andother infections as PVMV Sendai virus and parvo-virus have also occasionally been detected inanimals brought to the Institute from othersources. The new centralized animal facilities forrodents at the Karolinska Institute are designed forkeeping animals pathogen-free behind physicalbarriers. Ventilation. room construction andworking routines have all been designed to preventthe rapid spread of infections, Health monitoringin these new facilitim is an important tool inkeeping rodent infections under control. In order[0 decrease the costs of health monitormg. an"extended soiled bedding scnlinel system” hasbeen developed.Materials and MethodsAnimalsSentinels are 5-7 weeks old when taken into use,Female NMRI mice from the National Vetcrinarylnstitut: 0r Charles River Sweden AB. both inUppsala. Sweden. are used as mouse sentinels. Asrat sentincls, male or female PVG/Bkl from B&KUniversal. Sollentuna, chdcn are used. All threecolonies have a history of superior and consistentmicrobiological quality. Instead of purchasingsentinels. serologically negative animals with anormal immune system from one animal room canbe used as scntinels in the same room. We distm-guish between “l‘ack sentinels" and “room senti-ncls“ (Figure 1).      R Figure /, Rack and room sentincls S = rack sentlnels‘ R = room scmlncls‘ Arrows Indicate ways of sailed beddmgfrom rack sentincls to room scntlncls‘1/8Rack sentinelsA cage with 2-4 rack sentinels is placed at thebottom right of each rack. These sentinels aregiven small amounts of used bedding from each ofthe other cages in the rack at the time of cleaning.Cages are changed twice a week. staiting at the topleft and ending at the bottom right Hands arewashed 01‘ gloves changed before changing cagesin the next rack as the most efficient transmissionof mouse corona virus is through personnelspreading the virus with their hands (Honiberger1997).Room NemmelxOne cage with 2-4 mom sentinels is placed in aspecially chosen place in the animal room llachtime cages are changed‘ small amounts of usedbedding from all rack sentinel cages are placedinto the room sentinel cage, The room sentinelcage is changed last.Cagi'ngThe animals are caged either in regular MacrolonIII or Macrolon IV cages‘ or in individually ven-tilated microisolators in Vent—A»Cage racks(Iwarsson & Nore'n 1992). The rack sentinels arecaged in the same manner us the other animals inthe rack and the room sentinels are housed in afiltcrtop cage.Health monitoring proceduresThe minimum housing time before a sentinel canbe used for testing is 3 weeks. A complete healthmonitoring of two room sentinels is performedonce or twice a year at the Swedish National Vet-erinary Institute according to their current standard(SVA 1997) completed with a number of viruses.In addition, testing for corona Virus is presentlycarried out every two weeks and pinworms everytwo months. Sera are tested individually for en-rona virus antibody and intestines of two sentinelmice from the same cage are pooled for pinwormexamination. Room sentinel rats are examined forpinworms by cellophane tape tests.Rack sentinels are monitored when room sentinelsare found positive for any infection Two racksentinels from each rack are tested and thus infec-tion can be traced to racks in the. room. RackScandVJ Lab Anim Scx N03 1997 Vol 24sentinels that have not been used for testing withina year are replacedResultsThe system described has been in use since No-vember 1996‘ and proved efficient on two occa-sions when MHV—infections occured in one ani—mal departmenL On both occasions the roomsentinels were found serologically positive againstMHV by ELISA. with titers of 1250. When therack sentinels were tested. rack sentinels in 5 outof [8 racks, and 4 out of 6 racks. respectively,showed Ml IV titers of l :250 0r l:l25().DiscussionThe reliability of any soiled bedding sentinelsystem is dependent on the spread of infections viadirty bedding 1n the recent history ofthe Karolin—ska Institute corona virus infections and pin-worms, both of which spread via soiled bedding,have been the most common infections detected,It is important to be aware ofthe time delay beforeroom sentinels get positive in case a pathogen isintroduced into the room. The mouse pinwormAspicularls letraplera has a prepatence period of24 days (Owen 1992) and a virus infection mayhave been present {or 1-2 weeks in the infected .animal before seroconversion.Detection of infections that do not, or only slowly,spread via soiled bedding may call for supple-mentary testing by random sampling from theanimal colonyThe extended soiled bedding system describedhere is economically effective and to some extentalso labor saving because only the room sentinelsrequire regular testing.SummaryA soiled bedding sentinel system with rack senti-nels and mom sentinels is described. Rack senti-nels get soiled bedding from the other cages in therack. the room sentinels get soiled bedding fromthe rack sentinels Only room sentinels are regu-larly tested. The method is economically effectiveand labor saving and has on two occasions provedefficient when mouse corona virus has appeared inan animal depanment at the Karolinska Institute.119Scand 1 Lab Anim. Sci. No.3. 1997 Vol. 24ReferencesHomberger. l~'. R: Hntemtmpic mouse hepatitisvirus. Laboratory Animals 1997,31, 97-115,lwarsmn, K: Laboratory animal health moni»toring: an introductory survey 0fthe universitymouse breeding colonies in Stockholm. Pro-ceedings of the third CFN Symposium held inStockholm. Sweden May 9-11. 1988. ActaPhysiol Scand 1990. 140. Suppl, 592. 139—140,[20Staten: l’eterim’z’rmedicmnska Anstalz (SVA):l-‘éirsdksdjursverksamhet 1997: Under—sfiikningar avseende férséksdjur vid SVA.Trycksak SVA, Uppsala 1997.[warssom K. & L. Norén: Comparison of mieroen-vironmental conditions in standard versusforcedeir ventilated rodent filter-top cages.Scand. J. Lab. Anim. Sci. 1992, 19, 167-173.Owen. D. G.: Parasites of laboratory animals.Laboratory Animal Handbooks No. 12. Labo-ratory Animals Ltd, London 1992.

An extended soiled bedding sentinel system

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An extended soiled bedding sentinel system

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