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Helminth Fauna of the Golden Hamster<I> Mesocricetus Auratus</I>

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Helminth Fauna of the Golden Hamster<I> Mesocricetus Auratus</I> Helminth Fauna of the Golden Hamster Mesocricetus auratus in Brazil ROBERTO MAGALHÃES PINTO, DS,* LUCINEIDE GONÇALVES, MS, DELIR CORRÊA GOMES, DS, AND DELY NORONHA, BS Helminth fauna of conventionally maintained hamsters from institutional animal houses that supply the research community with laboratory animals and from an openly kept control group, randomly purchased in a pet shop in the State of Rio de Janeiro, were evaluated and compared. Necropsied animals from institutional suppliers were infected with the oxyurid nematodes Syphacia criceti and S. mesocriceti and with the cestode Rodentolepis nana; those from the pet shop were infected with S. mesocriceti and R. nana. These are the first morphometric data that are based on Brazilian samples of these species parasitizing hamsters. Mesocricetus auratus is a newly recorded host for S. criceti, previously recovered from Oryzomys subflavus and Calomys callosus in Brazil. The potential of pet and laboratory hamsters in the spreading of helminth infections to humans is also considered. Because of the role laboratory animals play in the evaluation bran wheat, bran soya, leguminous hay, ground corncob, cal- of several biological parameters in scientific research and in light cite limestone, bicalcium phosphate, premixed amino acids, of the program established to control the sanitary conditions of vitamins, and minerals; PR 145300104, Ministry of Agriculture, Brazilian institutional animal houses, we have developed proce- Colombo, Paraná, Brazil) and filtered water from nursing bottles dures to provide a reliable survey of the helminth fauna occurring adapted to the covers. Bedding and chow were sterilized (heated in several animal models. The models we targeted are commonly for 20 min at 1108C) only for animals in group A. The tempera- maintained but not often evaluated, considering the few data ture of the animal room was maintained at 18 to 228C. Housing on the parasites they may harbor. The present approach is re- was in accord to Brazilian guidelines for the care and use of lated to nematodes and cestodes collected in hamsters from two laboratory animals (11). institutional animal houses and a pet shop in Rio de Janeiro. The hamsters from the pet shop (weight, 70 to 90 g; age, 6 to Hamsters are used mainly in assays related to experimental 9 weeks) were kept together in 95.0 3 51.0 3 35-cm cages simi- infections (1, 2), pathology (3-5), host-parasite relationships (6), lar to those used in the animal houses. They received ad libitum immune responses, immunodiagnoses (7), and drug therapies Labina pellets (corn, wheat bran, soya bran, meat flour, raw rice (8). In addition, pet shop hamsters were investigated as a com- bran, calcium carbonate, bicalcium phosphate, salt, premixed parative outside group, because little attention has been given amino acids, vitamins, and minerals; Agribands Purina do Brasil to the possibility of acquiring parasitic infections from rodents Ltd., Itaguaí, Rio de Janeiro, Brazil) and untreated water from obtained from commercial sources. Further, the general popu- glass containers on the bottom of the cage. The cages were openly lation probably is unaware of any threat of helminth infection maintained at room temperature for 3 days after they were de- from pet rodents. Results obtained thus far add new data to the livered to the pet shop by a farm supplier. Husbandry procedures previous major studies of helminths that parasitize laboratory at the farm were the same as those adopted in the pet shop. animals in Brazil (9, 10). This report is important because para- The husbandry practices at the pet shop involved the pres- sites may act as variables, usually unsuspected, in experiments. ence of open food packages next to the animals for sale. Considering that the maximum mean temperatures in Rio de Materials and Methods Janeiro always exceed 328C in the hottest sectors, where abso- 8 Animals. We obtained 30 adult male specimens of the golden lute temperatures higher than 40 C commonly occur (12), the hamster Mesocricetus auratus (weight, 70 to 170 g) from two dif- doors of the shop, although closed at night, were designed to ferent institutional animal houses and a pet shop in Rio de provide a large screened window-like to improve ventilation. Janeiro, Brazil. The animals were allocated into groups A, B, Nevertheless, this floor-level entrance permits the free access of and C (10 animals/group) according to their source. The origi- insects, mice, and rats (attracted by the availability of food) into nal source of institutional animals is unknown, but closed the shop, thereby improving the maintenance of the parasite breeding colonies have been maintained in the institutions for life-cycles in the study animals. more than 20 years. Pet shop hamsters were considered as an Parasites. Immediately after their arrival at the laboratory, outside openly kept control group in the comparison of the preva- hamsters were examined for helminths by using a modified anal lence of the various helminths and intensity of parasitism. The swab technique (10) and sacrificed in an ether chamber accord- suppliers were not identified by name, because of ethical rea- ing to ethical procedures (11). The procedures for processing sons. The microbiological status of the animals was not specified. of helminths for study and their classification have been reported Husbandry. Prior to their arrival at the laboratory, the ham- elsewhere (9). “En face” slides were prepared by using jelly sters from the institutional animal houses (weight, 94.5 to 170 mounts (13). Photomicrographs derived from a Axiophot mi- g; age, 10 to 52 weeks) were maintained conventionally in groups crophotographic system (Zeiss, Jena, Germany) using T400 CN of 10 in 40.0 3 33.0 3 16.0-cm plastic cages with stainless-steel film (Kodak, Guadalajara, Jalisco, Mexico). NHR stands for New screened covers and daily changed bedding of pine shavings. Host Record. Studied specimens were deposited in the Animals received ad libitum Nuvital pellets (ground whole corn, Helminthological Collection of the Oswaldo Cruz Institute (CHIOC) either as whole mounts or wet material. Laboratorio de Helmintos Parasitos de Vertebrados, Departmento de Helmintologia, Instituto Oswaldo Cruz, Av. Brasil 4365, 21045-900 Rio de Janeiro RJ, Brasil Results *Corresponding author Descriptions refer only to the main morphological data of the Volume 40, No. 2 / March 2001 CONTEMPORARY TOPICS © 2001 by the American Association for Laboratory Animal Science 21 Figure 1. Syphacia criceti. (A) Male, whole body, lateral view. Bar, 0.08 mm. (B) Anterior portion of male, lateral view. Bar, 0.02 mm. (C) Head of female, “en face” view. Bar, 0.01 mm. (D) Eggs “in utero.” Bar, 0.03 mm. (E) Posterior extremity of male, lateral view. Bar, 0.02 mm. (F) Posterior portion of male, lateral view. Bar, 0.07 mm. Bar of Fig. A, common to Figs. B-F. specific diagnosis and are based on the helminths recovered worms, white when alive. Great sexual dimorphism. Males: body, during the present investigation. 1400 to 1600 (mean, 1500) mm long, 90 to 100 (mean, 94) mm Syphacia criceti Quentin, 1969. (Fig. 1, A-F) wide, with three mamelons on the ventral surface, of which the (i) Morphometrics based on 10 specimens, five males and five anterior is less prominent than are the two posterior. Esopha- females. Oxyuroidea, Oxyuridae. Small, somewhat slender gus, with bulb, 250 to 260 (mean, 255) mm long. Nerve ring 110 22 CONTEMPORARY TOPICS © 2001 by the American Association for Laboratory Animal Science Volume 40, No. 2 / March 2001 Figure 2. Syphacia mesocriceti. (A) Male, whole body, lateral view. Bar, 0.1 mm. (B) Anterior portion of female, lateral view. Bar, 0.03 mm. (C) Eggs “in utero.” Bar, 0.02 mm. (D) Head of female, “en face” view. Bar, 0.01 mm. (E) Posterior portion of male, lateral view. Bar, 0.2 mm. Bar of Fig. A, common to Figs. B-E. to 144 (mean, 130) mm from anterior end and excretory pore caudal papillae present. Cloacal aperture 138 to 140 (mean, 139) 460 to 470 (mean, 465) mm from anterior end. Single spicule, mm from posterior end. 78 to 80 (mean, 79) mm long. Gubernaculum 30 to 32 (mean, Females: body 3400 to 3800 (mean, 3500) mm long, 210 mm 31) mm long, with a hook-shaped distal process. Three pairs of wide. Esophagus, with bulb, 360 to 370 (mean, 366) mm long. Volume 40, No. 2 / March 2001 CONTEMPORARY TOPICS © 2001 by the American Association for Laboratory Animal Science 23 Figure 3. Rodentolepis nana. (A) Scolex with armed rostelum. Bar, 0.02 mm. (B) Mature proglottids. Bar, 0.07 mm. (C) Gravid proglottids. Bar, 0.07 mm. (D) Eggs “in utero.” Bar, 0.02 mm. Bar of Fig. A, common to Figs. B-D. Nerve ring 160 to 190 (mean, 173) mm from anterior end and mounts) and 33,875 (wet material). excretory pore 360 to 540 (mean, 462) mm from anterior end. Syphacia mesocriceti Quentin, 1971. (Fig. 2, A-E) Vulva 840 mm from anterior extremity. Eggs 111 to 120 (mean, (i) Morphometrics based on 10 specimens, five males and five 116) mm long, 43 to 48 (mean, 46) mm wide. Anus 360 to 390 females. Oxyuroidea, Oxyuridae. Small, thick worms, white when mm from posterior end. alive. Cephalic inflations conspicuous. Great sexual dimorphism. (ii) Taxonomic summary. Host: Mesocricetus auratus Males: body 1080 to 1500 (mean, 1300) mm long, 80 to 90 (mean, (Waterhouse, 1839)-NHR. Site of infection: small intestine. Dis- 85) mm wide, with three prominent mamelons on the ventral tribution: Brazil. Specimens studied: CHIOC no. 34,205a-f (whole surface of posterior portion. Esophagus, with bulb, 190 to 210 24 CONTEMPORARY TOPICS © 2001 by the American Association for Laboratory Animal Science Volume 40, No. 2 / March 2001 (mean, 199) mm long.
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