Raccoons, skunks, and opossums (N=57, 60, and 60, respectively) were necropsied for parasite detection and identification from September, 2001 until April, 2002. Qualitative coprological exams and adult Baylisascaris collections have been completed. Fecal stages and/or types found were Baylisascaris and Strongyloides-type (skunks and raccoons); Capillaria and Trichostrongyletype (raccoons and opossums); Acanthacephalan and ascarid type (opossums only); free larvae (skunks only); and coccidial (protozoan) oocysts (all three host species). Adult Baylisascaris were recovered from 33.3% of the raccoons and 58.3% of the skunks. Data collection relative to this survey, which is still ongoing, includes the determination of Sarcocystis prevalence in excised skunk and raccoon muscle as well as prevalence and magnitude of the numerous enteric helminths recovered from the three host animals

Belviy, Michelle

Robins, Jennifer

Tucker, C. A.

Yazwinski, T. A.

English

UARK (University of Arkansas )

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences Volume 3 Article 6 Fall 2002 Preliminary results from a survey on the prevalence of parasitic helminths and protozoa in raccoons, opossums, and skunks Michelle Belviy University of Arkansas, Fayetteville T. A. Yazwinski University of Arkansas, Fayetteville C. A. Tucker University of Arkansas, Fayetteville Jennifer Robins University of Arkansas, Fayetteville Follow this and additional works at: https://scholarworks.uark.edu/discoverymag  Part of the Animal Diseases Commons, and the Animal Studies Commons Recommended Citation Belviy, M., Yazwinski, T. A., Tucker, C. A., & Robins, J. (2002). Preliminary results from a survey on the prevalence of parasitic helminths and protozoa in raccoons, opossums, and skunks. Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences, 3(1), 17-22. Retrieved from https://scholarworks.uark.edu/discoverymag/vol3/iss1/6 This Article is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences by an authorized editor of ScholarWorks@UARK. For more information, please contact scholar@uark.edu. THE STUDENT JOURNAL OF THE DALE BUMPERS COLLEGE OF AGRICULTURAL, FOOD AND LIFE SCIENCES 17Preliminary results from a survey on the prevalence of parasitic helminths and protozoa in raccoons, opossums, and skunks, withspecial reference toBaylisascaris spp.Michelle Belviy*, T.A. Yazwinski§, C.A. Tucker†,and Jennifer Robins* Michelle Belviy is a junior majoring in animal science.§ T.A. Yazwinski, faculty sponsor, is a professor in the Department of Animal Science.† C.A. Tucker is a research associate in the Department of Animal Science.Jennifer Robins is a graduate student majoring in Animal Science.ABSTRACTRaccoons, skunks, and opossums (N=57, 60, and 60, respectively) were necropsied for parasitedetection and identification from September, 2001 until April, 2002. Qualitative coprologicalexams and adult Baylisascaris collections have been completed. Fecal stages and/or types foundwere Baylisascaris and Strongyloides-type (skunks and raccoons); Capillaria and Trichostrongyle-type (raccoons and opossums); Acanthacephalan and ascarid type (opossums only); free larvae(skunks only); and coccidial (protozoan) oocysts (all three host species). Adult Baylisascariswere recovered from 33.3% of the raccoons and 58.3% of the skunks. Data collection relative tothis survey, which is still ongoing, includes the determination of Sarcocystis prevalence in excisedskunk and raccoon muscle as well as prevalence and magnitude of the numerous enterichelminths recovered from the three host animals.DISCOVERY VOL. 3, FALL 2002INTRODUCTIONMany pathogenic organisms are reservoired in wild(sylvatic) animals, which cause disease in domesticatedanimals as well as in humans (latter diseases referred toas zoonoses). Sarcocystis neurona is a protozoan parasiteof the opossum’s intestinal tract, but if the parasite isingested by a horse, central nervous system infection anddysfunction follow, culminating in a disease calledequine protozoal myeloencephalitis (EPM) (NAHMS,2001). All life cycles of S. neurona have not been totallydefined, especially in regard to the paratenic hosts thatboth reservoir and distribute this protozoan parasite(Dubey et al., 2001). Exposure of horses to the pathogenis common, with sero-positive rates of 50% or higher(Blythe et al., 1997). Fortunately, only a small percent-age of exposed horses develop EPM, with early detectionand treatment proving very successful (Fenger, 1996).Results from the current survey will be valuable inassessing the extent of pathogen availability in our area,a factor directly related to the health threat that exists forhorses.The other parasites targeted in the current survey areBaylisascaris procyonis and B. columnaris of the raccoonand striped skunk, respectively. These nematodes areentirely enteric in the above hosts, but assume aberrantmigrations (visceral, ocular, and neural larval migrans)in paratenic hosts including humans (Kazacos, 1986).These migrations are poorly diagnosed, and therapy isusually not obviated until central nervous systeminvolvement is evident (Kazacos, 1982). Knowledge ofthe prevalence of these nematodes is therefore veryimportant from the standpoint of human health con-cerns, especially in relation to those individuals who uti-lize the more natural parts of our “Natural State”.18MEET THE STUDENT-AUTHORI graduated in 1999 from Mount St. Mary Academy inLittle Rock. I am a junior honors student majoring in ani-mal science with an added pre-vet curriculum. I havereceived several scholarships and honors over the yearsincluding the Target All-Around Scholarship, Pre-Vet ClubScholarship, Arena Seat Scholarship, Meat SciencesScholarship, University Housing Resident AssistantScholarship, First Place-Gamma Sigma DeltaUndergraduate Research competition, Dale BumpersUndergraduate Research Grant, as well as several certificatesfor recognition of academic achievement.During the summer of 2000, I interned with a veterinari-an in Arizona and observed first-hand the procedures ofveterinary medicine in the feed lot industry. I plan to grad-uate in May of 2003 with a B.S. degree in animal science andcontinue my education in veterinary school.I am active in and have been an officer for several clubson campus including Pre-Vet Club, Alpha Zeta, SigmaAlpha, and Student Health Advisory Committee. I am alsoa member of the National Society for Collegiate Scholars,Gamma Beta Phi, and Golden Key. Currently, I am a resi-dent assistant for the medical sciences floor in Pomfret Hall.I came upon this field of research because of my fascina-tion with parasitology. Parasites are a major factor in ani-mal health, a field obviously very important to me. This study has helped me to expand my knowledge of ani-mals and their parasites. The information I have gained by studying the symbiotic relationship between animalsand helminths, identifying helminths, and learning time management to accomplish all of this, will be an excel-lent resource for me in veterinary school and beyond.I would like to thank Dr. Yazwinski, Dr. Chris Tucker, and Jennifer Robins for all the guidance, time, and laborthey have contributed to this project.Michelle BelviyMATERIALS AND METHODSRaccoons, opossums, and skunks were obtained start-ing in September of 2001 and collection continues at thistime (May, 2002). The primary source of specimens wasrecent intact road-kill (< 1 day from time of demise). Inaddition, live-trapped animals humanely euthanized viagun-shot were also used. These latter animals wereobtained under Arkansas Game and Fish Commissionpermit (License No. 197009 222001 112347). An ade-quate sample size of 60 animals per species was set as atarget, which has been reached for skunks and opossumsbut not for raccoons (N=57).All animals were necropsied according to standardprotocol as provided below:(1) Haircoat and skin inspected for external para-sites or lesions (i.e. mange).(2) Abdominal and thoracic cavities opened ven-trally along the entire midline.(3) Intestinal tract from stomach to rectumremoved (fecal sample obtained at this time for qualita-tive parasite egg detection via saturated MgSO4 flotationfollowed by microscopic examination).(4) Intestinal tract opened lengthwise and all con-tents washed over a #120 mesh sieve.(5) Sieve residue placed in formalin until subse-quent inspection, in total, at 10-40x for parasite collec-tion, identification, and counting.In addition to the above, sections of muscle wereobtained from all skunks and the majority of the rac-coons for shipment to Dr. Ellis Greiner (University ofFlorida School of Veterinary Medicine) for research as tothe content and identity of encysted protozoan parasites(e.g. S. neurona ).Microscopy was conducted with a stereoscopicmicroscope for magnifications < 40 X and a compoundmicroscope for magnifications > 40X. Small helminths(<2 CM) were cleared in lactophenol for 24 hrs. prior toinspection and/or photography. In regard to photogra-phy, egg and helminth images were received through acolor video camera and digitized to a computer forrecording.RESULTS AND DISCUSSIONAt the time of this writing, data collection is still inprogress. Results from completed qualitative coprologi-cal examinations as well as the isolation, identification,and counting of adult B. procyonis and B. columnaris canbe reported at this time.The prevalence rates of the different types of fecalstages detected during the coprological exams are givenin Table 1. Pictures of the various stages are given in Fig.1. Strongyloides-type eggs were the most frequentlyfound in skunk samples—an egg characterized by theinclusion of a motile larva. Additionally, 68% of theskunk samples were positive for coccidial (protozoan)oocysts and 32% were positive for B. columnaris eggs.For raccoon samples, Trichostrongyle-type eggs were themost common, followed in frequency by coccidialoocysts and B. procyonis eggs. The most prevalent eggtype found in opossum samples was acanthacephalan(“thorny-head”), a class of parasite only seen in theopossums obtained in the survey.The opossum is the primary if not sole definitive hostfor S. neurona. In our survey, only 9.7% of the opossumswere passing coccidial oocysts. In addition to a low fre-quency of oocyst shedding, the oocysts passed by theopossums in the survey did not appear (description andsize) to be S. neurona (Cheadle et al., 2001). This appar-ent lack of S. neurona detection in the surveyed opos-sums might be due to laboratory technique and chemi-cals, factors extremely critical for the successful isolationof S. neurona stages (E. Greiner, personal communica-tion). Therefore, documentation of S. neurona presencein Arkansas will hopefully be provided by the histologi-cal and molecular (DNA) work done at the University ofFlorida School of Veterinary Medicine from the raccoonand skunk muscle samples as obtained in this survey.Characterization of the adult Baylisascaris burdensfound in the surveyed raccoons and skunks is given inTable 2. Pictures of these nematodes are presented in Fig.2. Adult forms of these parasites were found in 33.3%and 58.3% of the raccoons and skunks, respectively.Rates of patent infections (positive for fecal egg counts)were slightly lower due most likely to worm maturity.Overall rates of infection by these nematodes willundoubtedly be higher, once all smaller parasite formsare identified and counted.As can be seen from the above data, Baylisascaris is ofhigh prevalence in our area. Numerous reports docu-ment the adverse effects of this parasite when it is acci-dentally ingested by humans and migrates to the eye(ocular larval migrans) or brain (neural larval migrans)(Kazacos, 1986; Kazacos, 1997; Kazacos and Boyce,1989). In addition, non-human vertebrates serving asparatenic hosts also suffer from the nematode’s larvalmigration (Clark et al., 1969; Kazacos, 1981; Stringfieldand Sedgwick, 1997). Therefore, without question, thisparasite is ubiquitous and poses considerable threat tohuman as well as animal health and should be scruti-nized along with the more notorious sylvatic, zoonoticparasites such as Giardia, Toxoplasma, Echinococcus, andTrichinella.THE STUDENT JOURNAL OF THE DALE BUMPERS COLLEGE OF AGRICULTURAL, FOOD AND LIFE SCIENCES 19DISCOVERY VOL. 3, FALL 2002ACKNOWLEDGMENTSFunding for this research has been obtained fromMerial, Inc., Fort Dodge Animal Health, and theUniversity of Arkansas Dale Bumpers College ofAgriculture, Food and Life Sciences.LITERATURE CITEDBlythe, L.L., D.E. Granstrom, D.E. Hansen, L.L. Walker, J.Bartlet, and S. Stamper, 1997. Seroprevalence ofantibodies to S. neurona in horses residing inOregon. J. Am. Vet. Med. Assoc. 210:525-527.Cheadle, M.A., J.B. Dame, and E.C. Greiner, 2001.Sporocyst size of isolates of Sarcocystis shed by theVirginia opossum. Vet. Parasit. 95:305-311.Clark, G.M., C.B. Philip, and L. Fadness, 1969.Observations on the effect on mice of concurrentinfections of Ascaris columnaris and certain neu-rotropic arboviruses. Folia Parasitol. 16:67-73.Dubey, J.P., D.S. Lindsay, W.J.A. Saville, S. Reed, D.E.Granstrom, and C.A. Speer. 2001. A review ofSarcocystis neurona and equine protozoal myeloen-cephalitis (EPM). Vet. Parasitol. 95:89-131.Fenger, C.K. 1996. EPM (equine protozoal myeloen-cephalitis): Early detection means more successfultreatment. Large Animal Veterinarian.March/April:14-20.Kazacos, K.R. 1981. Animal and public health implica-tions of the nematode genus Baylisascaris. Proc.Amer. Assoc. Vet. Parasitol. 26:21.Kazacos, K.R. 1982. Contaminative ability ofBaylisascaris procyonis infected raccoons in an out-break of cerebrospinal nematodiasis. Proc. Helm.Soc. Wash. 49:155-157.Kazacos, K.R. 1986. Raccoon ascarids as a cause of larvamigrans. Parasitol. Today. 2:253-255.Kazacos, K.R. Visceral, ocular and neural larva migrans.In Pathology of Infectious Diseases. Vol. 2. 1997 Ed.D.H. Connor et al. Stanford, CT. pp 1459-1473.Kazacos, K.R. and Boyce, W.M. 1989. Baylisascaris larvamigrans. J. Am. Vet. Med. Assoc. 195:894-903.Springfield, C.E. and C.J. Sedgwick, 1997. Baylisascaris :A zoo-wide experience. Proc. Am. Assoc. of ZooVeterinarians, pp. 73-77.NAHMS. 2001. Equine protozoal myeloencephalitis(EPM) in the U.S. USDA: APHIS: VS, CEAH,National Animal Health Monitoring System. FortCollins, Co. #N312.0501.20Table 1. Prevalence of progeny shedding by type of fecal stage and host.Characterization of Percentage of animals positivefecal stage/type by hostSkunk Raccoon OpossumBaylisascaris 32.0 25.6 0.0Strongyloides - type 70.0 7.7 0.0Trichostrongyle - type 0.0 84.6 41.9Capillaria 0.0 28.2 32.3Acanthacephalan 0.0 0.0 87.1Ascarid - type 0.0 0.0 16.1Free larvae 22.0 0.0 0.0Protozoan oocyst 68.0 74.4 9.7Table 2.  Comparative characterization of adult Baylisascaris burdens as found in this study.Host (Nematode)Item Raccoon Skunk(B. procyonis) (B. columnaris )Arithmetic mean for adult forms in positive animals 13.7 5.0Range in number of adult forms in positive animals 1-40 1-19% of animals infected with adult forms 33.3 58.3% of animals with positive fecal egg counts (% patent) 25.6 32.021Fig. 1b. Parasitic eggs from raccoon, fecal flotation.Fig. 1a. Parasitic eggs from opossum, fecal flotation.Fig. 1c. Parasitic eggs from skunk, fecal flotation.Egg/Oocyst Type1.  Trichostrongylid2.  Strongyloides3.  Baylisascaris4.  Capillaria5.  Acanthocephalan6.  Protozoan oocystTHE STUDENT JOURNAL OF THE DALE BUMPERS COLLEGE OF AGRICULTURAL, FOOD AND LIFE SCIENCESDISCOVERY VOL. 3, FALL 200222Fig. 2. Typical Baylisascaris specimens recovered andcounted as adultsBaylisascaris procyonis Baylisascaris columnaris

Preliminary results from a survey on the prevalence of parasitic helminths and protozoa in raccoons, opossums, and skunks

ScholarWorks@UARK

Discovery, The Student Journal of Dale Bumpers College ofAgricultural, Food and Life SciencesVolume 3 Article 6Fall 2002Preliminary results from a survey on the prevalenceof parasitic helminths and protozoa in raccoons,opossums, and skunksMichelle BelviyUniversity of Arkansas, FayettevilleT. A. YazwinskiUniversity of Arkansas, FayettevilleC. A. TuckerUniversity of Arkansas, FayettevilleJennifer RobinsUniversity of Arkansas, FayettevilleFollow this and additional works at: https://scholarworks.uark.edu/discoverymagPart of the Animal Diseases Commons, and the Animal Studies CommonsThis Article is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Discovery, The Student Journalof Dale Bumpers College of Agricultural, Food and Life Sciences by an authorized editor of ScholarWorks@UARK. For more information, pleasecontact scholar@uark.edu, ccmiddle@uark.edu.Recommended CitationBelviy, Michelle; Yazwinski, T. A.; Tucker, C. A.; and Robins, Jennifer (2002) "Preliminary results from a survey on the prevalence ofparasitic helminths and protozoa in raccoons, opossums, and skunks," Discovery, The Student Journal of Dale Bumpers College ofAgricultural, Food and Life Sciences. University of Arkansas System Division of Agriculture. 3:17-22.Available at: https://scholarworks.uark.edu/discoverymag/vol3/iss1/6THE STUDENT JOURNAL OF THE DALE BUMPERS COLLEGE OF AGRICULTURAL, FOOD AND LIFE SCIENCES 17Preliminary results from a survey on the prevalence of parasitic helminths and protozoa in raccoons, opossums, and skunks, withspecial reference toBaylisascaris spp.Michelle Belviy*, T.A. Yazwinski§, C.A. Tucker†,and Jennifer Robins* Michelle Belviy is a junior majoring in animal science.§ T.A. Yazwinski, faculty sponsor, is a professor in the Department of Animal Science.† C.A. Tucker is a research associate in the Department of Animal Science.Jennifer Robins is a graduate student majoring in Animal Science.ABSTRACTRaccoons, skunks, and opossums (N=57, 60, and 60, respectively) were necropsied for parasitedetection and identification from September, 2001 until April, 2002. Qualitative coprologicalexams and adult Baylisascaris collections have been completed. Fecal stages and/or types foundwere Baylisascaris and Strongyloides-type (skunks and raccoons); Capillaria and Trichostrongyle-type (raccoons and opossums); Acanthacephalan and ascarid type (opossums only); free larvae(skunks only); and coccidial (protozoan) oocysts (all three host species). Adult Baylisascariswere recovered from 33.3% of the raccoons and 58.3% of the skunks. Data collection relative tothis survey, which is still ongoing, includes the determination of Sarcocystis prevalence in excisedskunk and raccoon muscle as well as prevalence and magnitude of the numerous enterichelminths recovered from the three host animals.DISCOVERY VOL. 3, FALL 2002INTRODUCTIONMany pathogenic organisms are reservoired in wild(sylvatic) animals, which cause disease in domesticatedanimals as well as in humans (latter diseases referred toas zoonoses). Sarcocystis neurona is a protozoan parasiteof the opossum’s intestinal tract, but if the parasite isingested by a horse, central nervous system infection anddysfunction follow, culminating in a disease calledequine protozoal myeloencephalitis (EPM) (NAHMS,2001). All life cycles of S. neurona have not been totallydefined, especially in regard to the paratenic hosts thatboth reservoir and distribute this protozoan parasite(Dubey et al., 2001). Exposure of horses to the pathogenis common, with sero-positive rates of 50% or higher(Blythe et al., 1997). Fortunately, only a small percent-age of exposed horses develop EPM, with early detectionand treatment proving very successful (Fenger, 1996).Results from the current survey will be valuable inassessing the extent of pathogen availability in our area,a factor directly related to the health threat that exists forhorses.The other parasites targeted in the current survey areBaylisascaris procyonis and B. columnaris of the raccoonand striped skunk, respectively. These nematodes areentirely enteric in the above hosts, but assume aberrantmigrations (visceral, ocular, and neural larval migrans)in paratenic hosts including humans (Kazacos, 1986).These migrations are poorly diagnosed, and therapy isusually not obviated until central nervous systeminvolvement is evident (Kazacos, 1982). Knowledge ofthe prevalence of these nematodes is therefore veryimportant from the standpoint of human health con-cerns, especially in relation to those individuals who uti-lize the more natural parts of our “Natural State”.18MEET THE STUDENT-AUTHORI graduated in 1999 from Mount St. Mary Academy inLittle Rock. I am a junior honors student majoring in ani-mal science with an added pre-vet curriculum. I havereceived several scholarships and honors over the yearsincluding the Target All-Around Scholarship, Pre-Vet ClubScholarship, Arena Seat Scholarship, Meat SciencesScholarship, University Housing Resident AssistantScholarship, First Place-Gamma Sigma DeltaUndergraduate Research competition, Dale BumpersUndergraduate Research Grant, as well as several certificatesfor recognition of academic achievement.During the summer of 2000, I interned with a veterinari-an in Arizona and observed first-hand the procedures ofveterinary medicine in the feed lot industry. I plan to grad-uate in May of 2003 with a B.S. degree in animal science andcontinue my education in veterinary school.I am active in and have been an officer for several clubson campus including Pre-Vet Club, Alpha Zeta, SigmaAlpha, and Student Health Advisory Committee. I am alsoa member of the National Society for Collegiate Scholars,Gamma Beta Phi, and Golden Key. Currently, I am a resi-dent assistant for the medical sciences floor in Pomfret Hall.I came upon this field of research because of my fascina-tion with parasitology. Parasites are a major factor in ani-mal health, a field obviously very important to me. This study has helped me to expand my knowledge of ani-mals and their parasites. The information I have gained by studying the symbiotic relationship between animalsand helminths, identifying helminths, and learning time management to accomplish all of this, will be an excel-lent resource for me in veterinary school and beyond.I would like to thank Dr. Yazwinski, Dr. Chris Tucker, and Jennifer Robins for all the guidance, time, and laborthey have contributed to this project.Michelle BelviyMATERIALS AND METHODSRaccoons, opossums, and skunks were obtained start-ing in September of 2001 and collection continues at thistime (May, 2002). The primary source of specimens wasrecent intact road-kill (< 1 day from time of demise). Inaddition, live-trapped animals humanely euthanized viagun-shot were also used. These latter animals wereobtained under Arkansas Game and Fish Commissionpermit (License No. 197009 222001 112347). An ade-quate sample size of 60 animals per species was set as atarget, which has been reached for skunks and opossumsbut not for raccoons (N=57).All animals were necropsied according to standardprotocol as provided below:(1) Haircoat and skin inspected for external para-sites or lesions (i.e. mange).(2) Abdominal and thoracic cavities opened ven-trally along the entire midline.(3) Intestinal tract from stomach to rectumremoved (fecal sample obtained at this time for qualita-tive parasite egg detection via saturated MgSO4 flotationfollowed by microscopic examination).(4) Intestinal tract opened lengthwise and all con-tents washed over a #120 mesh sieve.(5) Sieve residue placed in formalin until subse-quent inspection, in total, at 10-40x for parasite collec-tion, identification, and counting.In addition to the above, sections of muscle wereobtained from all skunks and the majority of the rac-coons for shipment to Dr. Ellis Greiner (University ofFlorida School of Veterinary Medicine) for research as tothe content and identity of encysted protozoan parasites(e.g. S. neurona ).Microscopy was conducted with a stereoscopicmicroscope for magnifications < 40 X and a compoundmicroscope for magnifications > 40X. Small helminths(<2 CM) were cleared in lactophenol for 24 hrs. prior toinspection and/or photography. In regard to photogra-phy, egg and helminth images were received through acolor video camera and digitized to a computer forrecording.RESULTS AND DISCUSSIONAt the time of this writing, data collection is still inprogress. Results from completed qualitative coprologi-cal examinations as well as the isolation, identification,and counting of adult B. procyonis and B. columnaris canbe reported at this time.The prevalence rates of the different types of fecalstages detected during the coprological exams are givenin Table 1. Pictures of the various stages are given in Fig.1. Strongyloides-type eggs were the most frequentlyfound in skunk samples—an egg characterized by theinclusion of a motile larva. Additionally, 68% of theskunk samples were positive for coccidial (protozoan)oocysts and 32% were positive for B. columnaris eggs.For raccoon samples, Trichostrongyle-type eggs were themost common, followed in frequency by coccidialoocysts and B. procyonis eggs. The most prevalent eggtype found in opossum samples was acanthacephalan(“thorny-head”), a class of parasite only seen in theopossums obtained in the survey.The opossum is the primary if not sole definitive hostfor S. neurona. In our survey, only 9.7% of the opossumswere passing coccidial oocysts. In addition to a low fre-quency of oocyst shedding, the oocysts passed by theopossums in the survey did not appear (description andsize) to be S. neurona (Cheadle et al., 2001). This appar-ent lack of S. neurona detection in the surveyed opos-sums might be due to laboratory technique and chemi-cals, factors extremely critical for the successful isolationof S. neurona stages (E. Greiner, personal communica-tion). Therefore, documentation of S. neurona presencein Arkansas will hopefully be provided by the histologi-cal and molecular (DNA) work done at the University ofFlorida School of Veterinary Medicine from the raccoonand skunk muscle samples as obtained in this survey.Characterization of the adult Baylisascaris burdensfound in the surveyed raccoons and skunks is given inTable 2. Pictures of these nematodes are presented in Fig.2. Adult forms of these parasites were found in 33.3%and 58.3% of the raccoons and skunks, respectively.Rates of patent infections (positive for fecal egg counts)were slightly lower due most likely to worm maturity.Overall rates of infection by these nematodes willundoubtedly be higher, once all smaller parasite formsare identified and counted.As can be seen from the above data, Baylisascaris is ofhigh prevalence in our area. Numerous reports docu-ment the adverse effects of this parasite when it is acci-dentally ingested by humans and migrates to the eye(ocular larval migrans) or brain (neural larval migrans)(Kazacos, 1986; Kazacos, 1997; Kazacos and Boyce,1989). In addition, non-human vertebrates serving asparatenic hosts also suffer from the nematode’s larvalmigration (Clark et al., 1969; Kazacos, 1981; Stringfieldand Sedgwick, 1997). Therefore, without question, thisparasite is ubiquitous and poses considerable threat tohuman as well as animal health and should be scruti-nized along with the more notorious sylvatic, zoonoticparasites such as Giardia, Toxoplasma, Echinococcus, andTrichinella.THE STUDENT JOURNAL OF THE DALE BUMPERS COLLEGE OF AGRICULTURAL, FOOD AND LIFE SCIENCES 19DISCOVERY VOL. 3, FALL 2002ACKNOWLEDGMENTSFunding for this research has been obtained fromMerial, Inc., Fort Dodge Animal Health, and theUniversity of Arkansas Dale Bumpers College ofAgriculture, Food and Life Sciences.LITERATURE CITEDBlythe, L.L., D.E. Granstrom, D.E. Hansen, L.L. Walker, J.Bartlet, and S. Stamper, 1997. Seroprevalence ofantibodies to S. neurona in horses residing inOregon. J. Am. Vet. Med. Assoc. 210:525-527.Cheadle, M.A., J.B. Dame, and E.C. Greiner, 2001.Sporocyst size of isolates of Sarcocystis shed by theVirginia opossum. Vet. Parasit. 95:305-311.Clark, G.M., C.B. Philip, and L. Fadness, 1969.Observations on the effect on mice of concurrentinfections of Ascaris columnaris and certain neu-rotropic arboviruses. Folia Parasitol. 16:67-73.Dubey, J.P., D.S. Lindsay, W.J.A. Saville, S. Reed, D.E.Granstrom, and C.A. Speer. 2001. A review ofSarcocystis neurona and equine protozoal myeloen-cephalitis (EPM). Vet. Parasitol. 95:89-131.Fenger, C.K. 1996. EPM (equine protozoal myeloen-cephalitis): Early detection means more successfultreatment. Large Animal Veterinarian.March/April:14-20.Kazacos, K.R. 1981. Animal and public health implica-tions of the nematode genus Baylisascaris. Proc.Amer. Assoc. Vet. Parasitol. 26:21.Kazacos, K.R. 1982. Contaminative ability ofBaylisascaris procyonis infected raccoons in an out-break of cerebrospinal nematodiasis. Proc. Helm.Soc. Wash. 49:155-157.Kazacos, K.R. 1986. Raccoon ascarids as a cause of larvamigrans. Parasitol. Today. 2:253-255.Kazacos, K.R. Visceral, ocular and neural larva migrans.In Pathology of Infectious Diseases. Vol. 2. 1997 Ed.D.H. Connor et al. Stanford, CT. pp 1459-1473.Kazacos, K.R. and Boyce, W.M. 1989. Baylisascaris larvamigrans. J. Am. Vet. Med. Assoc. 195:894-903.Springfield, C.E. and C.J. Sedgwick, 1997. Baylisascaris :A zoo-wide experience. Proc. Am. Assoc. of ZooVeterinarians, pp. 73-77.NAHMS. 2001. Equine protozoal myeloencephalitis(EPM) in the U.S. USDA: APHIS: VS, CEAH,National Animal Health Monitoring System. FortCollins, Co. #N312.0501.20Table 1. Prevalence of progeny shedding by type of fecal stage and host.Characterization of Percentage of animals positivefecal stage/type by hostSkunk Raccoon OpossumBaylisascaris 32.0 25.6 0.0Strongyloides - type 70.0 7.7 0.0Trichostrongyle - type 0.0 84.6 41.9Capillaria 0.0 28.2 32.3Acanthacephalan 0.0 0.0 87.1Ascarid - type 0.0 0.0 16.1Free larvae 22.0 0.0 0.0Protozoan oocyst 68.0 74.4 9.7Table 2.  Comparative characterization of adult Baylisascaris burdens as found in this study.Host (Nematode)Item Raccoon Skunk(B. procyonis) (B. columnaris )Arithmetic mean for adult forms in positive animals 13.7 5.0Range in number of adult forms in positive animals 1-40 1-19% of animals infected with adult forms 33.3 58.3% of animals with positive fecal egg counts (% patent) 25.6 32.021Fig. 1b. Parasitic eggs from raccoon, fecal flotation.Fig. 1a. Parasitic eggs from opossum, fecal flotation.Fig. 1c. Parasitic eggs from skunk, fecal flotation.Egg/Oocyst Type1.  Trichostrongylid2.  Strongyloides3.  Baylisascaris4.  Capillaria5.  Acanthocephalan6.  Protozoan oocystTHE STUDENT JOURNAL OF THE DALE BUMPERS COLLEGE OF AGRICULTURAL, FOOD AND LIFE SCIENCESDISCOVERY VOL. 3, FALL 200222Fig. 2. Typical Baylisascaris specimens recovered andcounted as adultsBaylisascaris procyonis Baylisascaris columnaris

https://scholarworks.uark.edu/cgi/viewcontent.cgi?article=1247&context=discoverymag

Preliminary results from a survey on the prevalence of parasitic helminths and protozoa in raccoons, opossums, and skunks

Abstract

Similar works

Full text

Available Versions

UARK (University of Arkansas )

ScholarWorks@UARK