Effective Eradication of Pinworm Infection (Syphacia truris, Syphacia obvelata) from a Large Rodent Breeding Center

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1 -EliIl\!V:H~ Taiwan Vet J 30 (2): , 2004 Effective Eradication of Pinworm Infection (Syphacia truris, Syphacia obvelata) from a Large Rodent Breeding Center 1,2Chung-Tiang LIANG, lping-chin LEE, IShiann-Ching WU, lyen-te HUANG, lwei-jeng CHANG, lta-yu HSC, * 1,3San-Chi LIANG 1 National Laboratory Animal Center, National Applied Research Laboratories, Taipei, Taiwan 775, ROC 2 Department and Graduate Institute of Veterinary Medicine, College of Bioresources and Agriculture, National Taiwan University, Taipei, Taiwan 706, ROC 3 Laboratory Animal Center, National Defense Medical Center, Taipei, Taiwan 774, ROC (Received: February 2, Accepted: March 30, 2004,) ABSTRACT In the routine health monitoring of laboratory animals in our breeding and research center, rat pinworm, Syphacia muris, was detected in the research rat colony(10/16)and mice pinworm, Syphacia obve/ata, in barrier SPFmice( 1/28). A combination anthelmintic regimen was designed to eradicate this infection. At first, 0.1% ivermectin solution was sprayed in both mice and rat cages on days 0, 14and 28, while piperrazine citrate was administered twice weekly at a rate of 3 gil in the drinking water on days 7, 10, 21, 24, 35 and 38. Ivermectin was then added to the drinking water (0.007 mg/ml) on days 42 and 49 in both rats and mice, followed by o ral administration of fenbendazole-medicated chow in rats (150 ppm) and 0.2% thiobendazolemedicated chow in mice weekly for 6 weeks. Other measures to facilitate eradication in contaminated animal rooms were conducted simultaneously and included the use of filter-top cages, environmental decontamination by flame, research colony depopulation, breeding cessation and decrease in colony size. The colony was monitored for 24 months during and after treatments. Findings from examination of 4862 cellophane-tape impressions of the anus, 1109 cecal examinations from euthanized rats and mice, as well as 347 MIF concentration stool smears confirmed the efficacy of the treatment. This is the first report for the successful eradication of pinworms in large scale breeding colonies including both rats and mice. [Liang CT, Lee PC, Wu SC, Huang YT, Chang WJ, Hsc TY, Liang SC. Effective eradication of pinworm infection (Syphacia muris, Syphacia obvelata) from a large rodent breeding center. Taiwan Vet J 30(2): , Corresponding author TEL: ( ext 18180), simon@mail.ndmctsgh.edu.tw] Key words: Pinworm, Syphacia muris, Syphacia obvefata INTRODUCTION Pinworms, or oxyurids, belong to the family oxyuridae in the order Ascaridorida [5J. They have three species: Syphacia olroelata, Syphacia muris, and Aspiculuris tetraptera. Syphacia obvelata is commonly seen in mice, and Syphacia muris is commonly seen in rats. However, both species of Syphacia spp. can patently infect rats or mice [15J. Pinworm infection with Syphacia oboelata or Syphacia muris is a common problem in laboratory

2 Chung-Tiang LIANG et al 107 rodent colonies. Although parasitized rodents may lack clinical signs of infection, heavy infection can cause severe gastrointestinal disturbance such as diarrhea, dehydration, rectal proplapse [9 J, colitis [14 J and water transport of electrolyte [18]. The life cycles of S. obvelata and S. muris are 11 to 15 days and 7 to 9 days respectively. The adult worms inhabit the cecum and colon. After copulation, gravid females travel through the colon, e merge from the anus, and deposit their ova in the perianal region. This creates a therapeutic challenge because even if worms are effectively eradicated, infection can recur. The rodents ingest ova when they clean their perianal region or if larvae hatched from ova deposited around the anus retroinfect into the colon. Therefore, the eradication of pinworms is extremely difficult, especially from a breeding colony of rodents. Numerous anthelmintic agents have been used to treat pinworm, inducing piperazine citrate [9,13,18,19J, piperazine hexahydrate, or adipate, trichlorfon, dichlorvos, haloxon [ 18], % oral thiabendazole in food [16,18], pyrantel pamoate [11], ivermectin in drinking water [10,13,19 J or by spraying [ 11,12 J, ivermectin by oral gastric intubation [1,4J, and 150 ppm Ienbedazole [8]. However, there have been very few reports of successful eradication in large scale of breeding colonies, including only one report of eradication of Syphacia obvelata in a mice breeding colony [13 ], one report of Syphacia muris eradication in a rat colony [8]. No report involves both rat and mice breeding colonies with Syphacia obvelata and Syphacia muris infection. Here we report the successful eradication of pinworm infection in both rat and mice colonies with thousands of animals. Several factors are considered which led to the use of our anthelmintic therapy, including the effectiveness of the anthelmintic agents, labor cost, animal adaptations to treatment, and the availability of treatments in Taiwan. Our experience may serve as a successful example of pinworm eradication program for large rodent breeding centers. MATERIALS and METHODS Laboratory Animals The colonies were maintained in a (specific pathogen free, SPF) barrier, with a total 12 animal holding rooms. Yearly average census was approximately 6, 100 breeding rats, 12, 470 breeding mice, and 124, 019 weanling rats and mice, all of which were for sale. These mouse and rat colonies consisted of numerous inbred strains and outbred stocks including Wistar, Long-Evans, SD, Lewis, SHRINCr!, WKY, F344, BN rats and ICR, C57BL/6], BALB/cAnN, BALB/cBy], C3H/ He], CBA/Ca], CBAIN, DBA/2], NZW, and CAnNCrj -Cg-Foxnl"u/Foxnl"u mice. Management and environment The mice and rats were housed in an air-conditioned room in uncovered polycarbonate shoebox cages (29 X 16.5 X 12 cm and 45.5 X 24 X em ) respectively, on hardwood bedding ( Beta-chip, Northeastern Inc. Warrensburg, NY ). The cage and bedding were changed twice per week, and cages were sanitized in a mechanical cage washer operating at 80t: Girton Manufacturing Co., Millville, P A). Water, food, bedding, and supplied materials were all sterilized by autoclave ( Eagle 3000 Vacamatic sterilizer, AMSCO, Apex, NC ) prior to use. All mice were fed a standard commercial diet (sterilizable PMI 5K55 mouse diet/auto 9F, PMI Feeds Inc., St. Louis, MO, USA. ; crude protein >18%, crude fat >9%, crude fiber <5%, ash < 6.5%, minerals <2.5 % ). All rats were fed a standard commercial diet ( sterilizable PMI 5L65 rodent lab auto diet, PMI Feeds Inc., St. Louis, MO, USA. ; crude protein >23%, crude fat >4.5%, crude fiber <6 %, ash <8% ). Water, supplied in bottles ( 400 ml in mice and 700 ml in rat ), was available ad libitum. Rooms were maintained at 21 ±2t:, with 60 ± 5% relative humidity and a 12/ 12-h light/dark cycle.

3 108 Effective eradication of pinworm infection Health monitoring A health-monitoring procedure was routinely performed to detect diseases in these SPF animals. Eight animals were randomly selected for health monitoring in each room under the assumption of 30% prevalence with a 95% confidence interval [ 15 ]. Rodents were euthanized, and evaluated serologically for exposure to a panel of adventitious murine viruses and Mycoplasma pulrnonis, Serum samples of mice were examined for ELISA antibodies to the following organisms: pneumonia virus of mice, reovirus (Reo-3), Sendai virus, lymphocytic choriomeningitis virus, Theiler's encephalomyelitis virus, mouse adenovirus, minute virus of mice, ectromelia virus, polyoma virus, K virus, Mycoplasma pulmonis and mice hepatitis virus (Charles River Laboratories, Wilmington, Mass. USA). Serum samples of rats were examined for ELISA antibodies to the following organisms: pneumonia virus of mice, reovirus (Reo-3), Sendai virus, lymphocytic choriomeningitis virus, Theiler's encephalomyelitis virus, mouse adenovirus, minute virus of mice, Toolan's H-l virus, Kilham's rat virus, sialodacryoadenitis virus, and Mycoplasma pulmonis (Charles River Laboratories, Wilmington, Mass. USA). Trachea PBS flush and cecum contents of rats and mice were examined for the following pathogens by bacteriological cultivation: Bordetella bronchiseptica, Corynebacterium kutscheri, Mycoplasma pulmonis (in the trachea PBS flush) and Salmonella spp. (in the cecum contents). For immunosupressed mice, Pseudomonas aeruginosa was also examined both in the trachea PBS flush and cecal contents. The ears and the surrounding pelage from each animal were examined directly under anatomical microscopy (Leica intralux' , Switzerland ) for ectoparasites. The cecal contents were placed in a petri dish with 2-3ml saline for further endoparasite examination. Cellophane tape impressions were performed for pinworm examination. The tissues samples were routinely processed to paraffin-embedded blocks. Sections (6Ilm) were stained with Gill and Mayer's ( GM ) haematoxylin (Muto Pure Chern. Co. Tokyo, Japan) and eosin (H&E). Examination for parasites during and after the treatment period During the first 9 weeks of the treatment period (days 0-63), we used cellophane tape impressions for monitoring animals in each room every other week. Sixteen to 20 samples per room, with each one from different cages, were randomly collected for pinworm examination. During the second stage (days ), the test sample number was increased to 30 cellophane tape examinations per month. Ten animals were sacrificed for cecal adult worm examination in the rooms housing C57BL / 61, BALB/cAnN, BALB/cBy1, CAnNCrj. Cg Foxnl."/Foxnl " mice which showed positive results on days Meanwhile, the cellophane tape examinations of inbred foundation rooms increased to 40 sections from different cages, and 20 sections monthly for other rodent rooms which did not show any positive results on pinworm examinations. In the two stages of intensive pinworm moni toring period (days 0-63 and days ), routine quarterly comprehensive health monitoring including complete parasitological examination, was also performed by taking 8 animals per room. Direct smear We added 2-3 ml saline, 0.9% NaCl, to 1 gram of cecal contents from each rodent. The conten ts were then mixed. A few drops were placed on a slide overlaid by cover slip, examined under light microscopy. Merthiolate iodine formaldehyde (MIF) concentration method We combined 9.4 ml of solution I Idistilled water 50 ml, formaldehyde 5 ml, thimerosal ( tincture of merthiolate, 1: 1000) 40 ml, glycerin 1 ml I with 0.6 ml of solution II (distilled water 100 ml, potassium iodide 10 g, iodine crystals 5 g) to make the MIF working solution. One gram of fresh cecal stool, pooled from 4 (rats) or 8 (mice) in one tube, was added to the 10 ml MIF working solution, mixed, then left to stand overnight for 24

4 Chung-Tiang LIANG et al 109 A B c o Fig. 1 Ce llophane tape preparat ion of Syphacia spp. eggs. Syphacia abvelata eggs are larger ( 134 X 36 p m) than those of S. muris ( 75 X 29 p m) and show an asymmetrical, crescent-shape. A Syphacia obvelata eggs, 100 X B Syphacia obvelata eggs, 400 X. C Syphacia muris eggs, 200 Xj D Syphacia muris eggs, 400 X. hours. T he n the inte rface and bott om layer we re collected, 3 ml ether was added, and the contents we re homogenized and cen trifuged at 2,000 rpm for 2 min. The smear of sediment was then examined for eggs and protozoa. Treatment regimen The same anthelmintic regimen was administered for the first six consecutive weeks in ba rrier for both rats and mice. Briefly, the treatment regimen was modified from Le Blanc [ 12 J. T he treatment solution consisted of 1 part 1% ivermectin (Ivomec', 10 mg/ml, MSD Agvet Merck, Sharp & Dohme BV Co. Inc., Haarlem, Netherlands) mixed with 9 parts tap water in a l L sp ray bottle. Each squirt at the" mist" setting of the l L spray bottle delivered approximately 0.9 to 1 ml (0.9 to 1 mg) ivermec tin ove r the entire cages. Mist from the spray falls on the en tire cage including the anima l, bedd ing, and th e cage walls ; the animal was not exposed to th e entire amount of ivermectin delivered in t he sp ray. Because of this, as we ll as ivermectiri's wide margin of safety [ 17J, overexposure was not considered a problem. We sp rayed the whole cages with 0. 1 % ivermectin, 2.7 to 3.0 mg ( three times of squ irt ) for each mouse cage and 5.4 to 6.0 mg (six times of squirt) for each rat cage once weekly, on days 0, 14, 28. Piperazine citrate was administered at a rate of 3 gil in the drinking water twice weekly, on days 7, 10, 21, 24, 35 and 38. Further treatment for rats and mice was given with iverrnectin, mg /ml in drinking water once weekly, on days 42 and 49. Ot her manipulations to facilitate eradication included the use of filter tops in cages of contaminated animal rooms.

5 110 Effect ive eradication of pinworm infection I (Mice) I (Rats) I I I I I I I I I I I I I I I 1 (Day) 110.1% ivermectin spray whole cages once weekly, 2.7 to 3.0 mg for mouse cages (three times of squirt), 5.4 to 6.0 mg for rat cages (six times of squirt), on the first days 0,14, 28, of the week. IIPiperazine citrate administered at a rate of 3 gil in the drinking water, twice weekly on days 7, 10, 21, 24, 35, 38. Ivermectin mglml in drinking water once weekly on days 42, 49 and drinking for a week Oral thiabendazole-medicated chow ( 0.2 % ) was feed ad libitum. Oral fenbendazole-medicated chow ( 150 ppm) was feed ad libitum. No treatment, fresh water and normal chow supplied Fig. 2 Schemat ic represent ation of treat ment regimens used for erad ication of Syphacia obve lata and Syphacia muris. Shaded intervals in dicat e duration of an thelm in t ic treatment. Environmental decontaminati on by flam e in th e barrier areas and research colony depopulation was also performed. Breeding cessation and reduction of colony size was performed in 1300 cages which housed 6000 mice including C57BL /6], BALBI cann and BALB/cBy], resulting in 300 cages in the room where the infection was identified, with 5 mice per cage. Different anthelmintic treatments wer e gi ven to rats and mice in anoth er 6 weeks preventi ve treatment period (Fig. 1). Oral 150 ppm Ienbendazole-rnedicated chow (Altromin Gmbh diet 1324, Germany) was fed in rat s; oral 0. 2 % th iobendazole-medi cat ed chow ( Altromin Gm bh diet 1434, Germany) was fed in mice starting on days 56 and 105 respect ively ( F ig. 2 ). These preven tive oral tre atment regimens wer e as descr ibed in previous reports in mice [16,18 ] and rats [8]. RESULTS In our routine health monitoring examinati on, no pathogens were detected on serology test and no pathogens or pot ential pathogens were det ect ed in th e intestinal conte nts and trac hea l lavage spec i men s based on routine bacteriol ogical cult ures. How ever, parasit e exam ina tion demonstrat ed rat pinworm, Syphacia m uris, in th e research colony (10 /16) and mice pinworm, Syphacia oboelata, in the barri er SPF mice ( 1/28 ). Although th ese tw o ty pes of Syphacia spp. eggs wer e very similar in sha pe, they could be dis tin guish ed according to the ir sizes. Syph acia olroelata eggs we re large r ( 134 X 36 /lm ) tha n those of S. m uris (75 X 29 /lm ) and showed an asym met rical, cresce nt -shape (F ig. 1). The eggs of S. spp. were slightly flat tened on on side and pointed on both ends. T he nucleus filled th e shell and frequently had progressed -

6 Chung-Tiang L1AJ'\lG et al III to a larval stage when laid. All of these research colonies were euthanized by CO 2 on the day of the positive finding for pinworm eggs, and no further treatment was given. At the first stage of treatment, pinworm eggs were found by cellophane tape impression on day s 10, 22, and 23 after one or two 7-day courses of 0.1 % ivermectin spray and on e 7-day course of piperazine citrate in drinking water. However, these animals were locallized in a separate room, and included BALB/cByj and C57BL/6j mice. More cellophane tap e impressions were taken randomly in this area, on e from animals in each of th e cage s on days and These results wer e all negative in th e 244 and 245 mice tested during th ese two periods respectively (Table 1). However, cellophane tap e impression s and direct sme ar ex amination of the rat coloni es in barrier areas show ed all negative results (Table 2). Bri efly, monthly intensive monitor ing was continued for 4 months afte r th e final tr eatment schedule was insti tuted ( days ). No more eggs wer e found. T ot ally, th e exami na tion of 4,862 cellophane-tape impression s of th e anus, cecal ex aminations from euthanized rats and mice, as well as 347 MIF con centrat ed stool sm ears during th e treatment period and for 21 months afterwa rds confirmed th e efficacy of treatment. (Table 1.2). DISCUSSION Pinworms ar e very contagious and hard to control, particularly in th e laboratory animal br eeding centers. Ova are very light and eas ily aerosolized, and thus are easily transmitted directly by fomites [12.15 ]. Very few successful cases hav e been reported. This study showed that th e combination of piperazin e and ivermectin for eight weeks can elimi nat e pinworm infecti on in infect ed rats and mice br eeding colonies. The subsequen t adm inistra tion of fenb endazole and thi ob end azole-medicated chow for six wee ks can success fully prevent recurrence of pinw orms in ra ts and mice respecti vely for mor e th an two years. As th e only laborat or y animal br eeding center in T aiwan, th e options for dealing with th e outbreak of pinworms infection wer e initially limited due to the lack of availability of certain treatments. Although fenbendazole medicated chow has been reportedly effective in large scale rats breeding colony [ 8], this agent was not available in large amounts in our country. The chow purchase pro cess from overseas would hav e required more th an one month. Iverrnectin is the 22, 23-dihydro deri vative of avermectin Bl, amacrocyclic lactone produced by an actinomycete, Streptomyces a ver m it ilis. It is active at extremely low dosage against a wid e variety of nematode and arthropod parasites, apparently via its action on the mediation of neurotransmission byr-aminobutyric acid (GABA). It is effec tive only in parasites with GABA-dependent neurotransmission [2 ]. Iverme ctin emerged as th e larvicidal drug of ch oice owing to its high efficacy and underdetectable toxic sid e effects. No toxi cit y is obse rved even at th e highest dose (25 mg vkg ) [17]. Piperazine is to exert " curate - like" effects on suscep tible nematod es, thereby paralyzing or nacrotizing th e worm and allowing it to be passed out with th e feces. The neuromuscul ar blocking is caused by blocking acet ylcholine at th e myon eural junct ion. The administration of single piperazin e citrat e at 200 mg vkg BW daily in drinking water for a week, follow ed by an int erruption for a week and ano ther treatment during th e third week has been used exte nsively. This protocol is easy to carry out and reduces th e number of oxyurids, but gener ally does not eradicate the parasites unless animals were moved to clean rooms [9 ]. Single tr eatment of ivermectin or pip er azin e prov ed uns uccess ful in th e eradication of pinworms, since viable eggs were det ect ed from tw o to seven months after th e end of treatment [13]. These tw o pinworm treatments are compatible and combined ivermectin and piperazine citrate altern atively in tap water have been successfully used [ ]. Thus, for th e first six week s we used th e comb ina tion of piperazine and rvermectin. O ur s tudy was sim ilar with othe r report s [ 1,4, 10J. th e pinwor m eggs persist ed at 10 and at days afte r one or two 7-day courses of O. 1% ivermectin spray treatment and one 7-day cours e of piper azine citra te in dr inking water. This mig ht

7 112 Effective eradication of pinworm infection Table 1. Results of parasite examination in the mice colony. Days Cellophane tape MIF Direct smear Pre-Rx' 1/ /28 0_7 b (10 th day) / /265 (22 nd, 23 M day) / / / / /903 0/181 0/ /582 0/53 0/394 Total 4/ a Pre-Rx-30 day period prior to start of treatment. bday 0: 11120/2000, start day of the pinworm treatment. Table 2. Pre-Rx' 0-7' Total Results of parasite examination in the rat colony. Days Cellophane tape 0/118 (1O/16)b 0/118 0/128 0/118 0/118 0/118 0/814 0/509 0/2041 MIF 0/25 0/60 0/85 Direct smear 0/27 0/159 0/258 0/444 Pre-Rx-30 day period prior to start of treatment. bclean conventional research colony was positive for pinworms on 11/9/2000. These animals were all euthanized on 11/10/2000. 'Day 0: 11/20/2000, start day of the pinworm treatment.

8 Chung-Tiang LIANG et al 113 have been due to the inability of ivermectin to affect pingworm ova [10J, piperazine compounds less effective against immature oxyurids [8J, and possible re-infection of the animals after treatment. However, ivermectin (2 mgvkg BW) given three times at 7-day or 9-day intervals to rats was effective for eradication of pinworms. In contrast, treatment given two times was ineffective [7J. A four or five 4-day courses of ivermectin treatment was suggested [10 J. The long period of treatment and posttreatment surveillance was considered crucial because Syphacia muris eggs have been reported to persist on the perianal region for up to 17 to 22 days [7,8J. We also noticed that some mice didn't drink the solution containing piperazine citrate very well, which might have influenced worm elimination. A few FVB and C57BL/6] mice developed blindness after spraying 1 % ivermectin on the whole cages, so we adopted another treatment regimen by administering mg/ml ivermectin in drinking water from the seventh to the eighth week. Anthelmintic concentration was based on a daily water intake of 15 ml for mice and 10 ml for rats per 100g body weight [6 J. From these data, the daily doses of piperazine would be 315 mglkg/day for mice and 210 mglkg/day for rats and the daily doses of ivermectin would be 1.05 mglkg/day for mice and 0.7 mglkg/day for rats [19 J. These data constitute only a rough estimation since the intake amounts depend on the nature of the diet, ambient temperature, ventilation, haircoat, breeding, health status and competition for water. However, we used doses of mg/ml ivermectin [13,19J in drinking water and adjusted piperazine citrate from 2.1 gil in drinking water [13,16,19 J to 3 g/ L for more anthelmintic effect [18 J. After the alternatively three 7-day courses of 0.1 % ivermectin spray, three 7-day course of piperazine citrate and two 7-day courses of ivermectin in drinking water (days 0-56) of treatment, no more eggs were detected. This result strongly indicated the treatment regimen aforementioned was effective in both rats and mice breeding colonies. For preventing the recurrence of eggs from contaminating the environment and after consideration of the labor cost, a second stage of medicated chow treatment was carried out for another 6 weeks. This included oral 0.2% thiabendazolemedicated chow in mice and 150 ppm fenbendazolemedicated chow diet in rats and the results were excellent. Fenbendazole and thiabendazole are both benzimidazole anthelmintics. Ta.ey are very safe and convenient to use in feed. The LD50 of fenbendazole in laboratory animals exceeds 10 gvkg when administered PO. It has been reported that feeding with 150 ppm fenbendazole medicated chow for five 7-day periods is successful in eliminating pinworm infection in rat breeding colonies [8 J. Furthermore, O.1 % thiabendazole-medicated chow has been shown to be a more potent anthelmintic than piperazine, with the advantages of being ovicidal, cheap, and safe to use for Syphacia obvelata [16J. Accordingly, we decided to administer these two drugs at the second stage of treatment for pinworms in rats and mice respectively. Intensive cellophanetape impressions have been taken during the treatment period (days 0-105) and for 21 months afterwards confirmed the efficacy of treatments. Anal tape preparations might not be a reliable diagnostic aid and thus should be considered as a limited means of identifying animals infected with the rabbit pinworm Passalurus ambigulus [3J and Aspiculuris tetraptera, because they normally deposit eggs in the colon rather than in the perianal region [18 J. However, this method had 88 % sensitivity in detecting rat pinworms [7 J. Cellophane tape impression may give 5-25 % intermittently false negative results during the follow-up period [ 10 J. Nevertheless, most reports have used cellophane tape impressions [1,3,7,8,10,12,13 J, examination of cecal contents for adult worms [1,8,10J, as well as flotation [10J for pinworm diagnostic criteria. The apparent persistence of eggs could be the result of low-level chronic or intermittent shedding by a small population of nematodes that was not immediately eliminated by treatment [7J. In summary, this is the first report of the successful eradication of pinworm infection in both rat and mice colonies with thousands of animals. Several factors are considered in our choice of an-

9 114 Effective eradication of pinworm infection thelmintic treatment, including effectiveness of the anthelmintic agent, labor cost, animal adaptation to treatment, and the availability of treatment chow diets from overseas. These results may serve as a successful example of pinworm eradication program for large scale rodent breeding centers. REFERENCES 1. Battles AH, Adams SW, Courtney CH, Mladinich CRT. Efficiency of ivermectin against natural infection of Syphacia muris in rats. Lab Anim Sci 37: , Campbell WC, FisherMH, Stapley EO, Albers-Schonberg G, Jacob TA. lverrnectin. a potent new antiparasitic agent. Science 221: , Duwel 0, Brech K. Control of oxyuriasis in rabbits by fenbendazole. Lab Anim 15: , Flynn BM, Brown PA, Eckstein JM, Strong D. Treatment of Syphacia obvelata in mice using ivermectin. Lab Anim Sci 39: , Flynn RJ, HeynemanD. Nematodes. In: Flynn RJ, ed. Parasites of laboratory animals. 1st ed. Iowa Sate University Press, Ames, USA, , HarknessJE, Wagner JE. Biology and husbandry In: Harkness JE, Wagner JE, ed. The biology and medicine of rabbits and rodents. 4th ed. Williams and Wilkins, USA, 3-73, Huerkamp MJ. Ivermectin eradication of pinworms from rats kept in ventilated cages. Lab Anim Sci 43: 86-00, Huerkamp MJ, Benjamin KA, Zitzow LA, Pullium JK, Lloyd JA, Thompson WD, Webb SK, Lehner NOM. Fenbendazole treatment without environmental decontamination eradicates Syphacia muris from all rats in a large, complex research institution. Contemp Top Lab Anim Sci 39: 9-12, Hoag WG. Oxyuriasis in laboratory mouse colonies. Am J Vet Res 22: , Klement P, Augustine JM, Delaney KH, Klement G, Weitz JI. An oral ivermectin regimen that eradicates pinworms (Syphacia spp, ) in laboratory rats and mice. Lab Anim Sci 46: , Kubo N, Iwaki T, Hara T, ShibaharaT. Effective eradication of rat pinworm, Syphacia muris, by anthelmintic therapy with pyrantel pamoate and ivermectin. (in Japanese) J Experi Anim Tech 34: 17-26, I) 12. Le Blanc SA, Faith RE, Montgomery CA. Use ot topical ivermectin treatment for Syphacia obvelata in mice. Lab Anim Sci 43: , Lipman NS, Dalton SO, Stuart AR, Arruda K. Eradication of pinworms (Syphacia obvelata) from a large mouse breeding colony by combination oral anthelmintic therapy. Lab Anim Sci 44: , Mullink JWMA. Pathological effects of oxyuriasis in the laboratory mouse. Lab Anim 4: , National Research Council. Digestive system. In: Infectious disease of mice and rats. 1 st ed. Institute of Laboratory Animal Resources, Committee on Infectious Diseases of Mice and Rats. National Academy Press, Wasington, DC, , Owen 0, Turton JA. Eradication of the pinworm Syphacia obve/ata from an animal unit by anthelmintic therapy. Lab Anim 13: , Sayles PC, Jacobson RH. Effects of various anthelmintic on larval stages of Nematospiroides dubius (nematodel. J Parasitol 69: , Taffs LF. Pinworm infections in laboratory rodents: a review. Lab Anim 10: 1-13, Zenner L. Effective eradication of pinworms (Syphacia muris, Syphacia obvelata and Aspicu/uris tetraptera) from a rodent breeding colony by oral anthelmintic therapy. Lab Anim 32: , 1998.

10 Chung-Tiang LIANG et al 115 實驗動物中心蹺蟲感染之有效防治 1,2 梁鍾鼎 1 李秉進 1 吳憲青 1 黃彥智 1 張維正 1 許德育 1,3* 梁善居 1 財團法人國家實驗研究院國家實驗動物中心, 115 台北市南港區研究院路二段 128 號 2 國立台灣大學生物資源暨農學院獸醫學研究所, 106 台北市大安區羅斯福路四段一號 3 國防大學實驗動物中心, 114 台北市內湖區民權東路 161 號 ( 收稿日期 : 93 年 2 月 2 日 接受日期 : 93 年 3 月 30 日 ) 摘要國家實驗動物中心在 89 年 1 1 月每季例行健康監測時發現外圍研發組動物房 so 大鼠出現大鼠繞過 (Sy, 帥 acia muris, 10/16), 隔離區小鼠發現小鼠蹺氫 (Syphacia obvelata, 1/28), 立即撲殺外國區所有動 物, 並對隔離區動物開始投藥 使用十倍稀釋之 1 % (10 mg/ml ) Ivermectin 混合後, 裝於一公升澆花瓶 中噴灑鼠籠 小鼠籠噴 ; 買三次, 大鼠籠噴灑六次 噴 ; 灑頻率為每週一次, 分別於第 天間隔投藥 在第 及 38 天時全面供應動物房 p i pe r ra z i n e citrate, 3 gil 加於飲水中投藥, 每週二次 但在投藥過程中, 肛門貼片發現蹺蟲蟲卵於投藥期第 1 0 及 天仍出現於感染房 BA L B /c 小鼠 所以決 定於第 42, 的天使用 O. 7 mg/ml Ivermectin 添加於飲水中, 每遇一次 同時於第 5 別的天投藥期, 大 鼠使用 1 田 ppm fenbendazole 加藥飼料, 小鼠使用 0. 2% thiabendazole 加藥飼料預防再感染 其它配合措 施包括感染動物房全面鼠籠加葦, 可疑污染區以噴火燄殺蟲卵, 研發組動物全數撲殺, 感染區減產及停止配 種, 經連續 2 年監測, 總計肛門貼片檢查相 62 項次, 腸道抹片 項次, MIF 濃縮蟲卵 347 項次檢查, 確 定驅車效果有效 [ 梁鍾鼎 李秉進 吳憲青 黃彥智 張維正 許德育. 梁善居 實驗動物中心境蟲感染 之有效防治 台灣獸醫誌 3 0 ( 2 ) : , 連絡人 TE L : ( ext ), simon@mail.ndmctsgh.edu.tw] 8 軍事 :.t 會品, 丈 "fjljilij, /J 峙, 書益