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Home , Cryptosporidiosis, Cryptosporidium hominis, Cryptosporidium parvum, Fenbendazole

Article #3 CE in Cats and

David S. Lindsay, PhDa Anne M. Zajac, DVM, PhD Virginia-Maryland Regional College of Veterinary Medicine

ABSTRACT: was recognized as an important in the early 1980s. Early studies assumed that all infections in , including humans, were caused by the parasite . Recent studies using molecular biologic tools and host- specificity studies indicate that cats and dogs have their own unique of Crypto- sporidium (C. felis and C. canis, respectively). Surveys indicate that up to 38.5% of cats and up to 44.8% of dogs are infected with Cryptosporidium spp. Initial studies indicate that owning a cat or does not increase the risk of humans acquiring cryptosporidiosis, although human infections with C. felis and C. canis have been found in patients with AIDS, immunosuppressed patients, and children from impoverished areas. Clinical signs of cryptosporidiosis in cats and dogs vary from none to chronic or intermittent diar- rhea. Fluids and other supportive measures should be used in with , but there is no proven safe and effective treatment of cryptosporidiosis.

embers of the genus Cryptosporidium AIDS, and it was later found in immunocom- are in the protozoan Apicom- petent humans who had been exposed to Mplexa. They are -like parasites infected dairy calves.3 Several groups of that develop in the microvillous border of researchers conducted studies in which C. epithelial cells in the digestive, respiratory, and parvum was successfully transmitted from urinary tracts of vertebrates.1 Recent molecular calves to young animals, including cats and phylogenetic studies indicate that cryptospo- dogs.1,3 Successful cross-species transmission ridia are more closely related to the gregarine studies with C. parvum led to the proposal that parasites of invertebrates than to the true coc- the organism was responsible for all infections cidial parasites of vertebrates.2 This may explain in mammals.4 Most parasitologists embraced why cryptosporidia are not sensitive to chemo- this concept, which has been taught in most therapeutic agents normally used to treat coc- veterinary schools since the 1980s. Recent stud- cidial infections.1 In the early 1980s, Cryp- ies of Cryptosporidium spp from cats,5–10 tosporidium parvum was identified as a major dogs,11–13 and humans14 indicate that these cause of intestinal in patients with organisms are biologically and genetically dif- ferent from C. parvum; thus they are now con- a Email comments/questions to Dr. Lindsay receives funding sidered separate species. Cryptosporidium felis is from Bayer Health and 5 [email protected], primarily found in cats and Cryptosporidium Merck & Company. Neither 11 fax 800-556-3288, or log on to company has been involved in canis in dogs ; is the www.VetLearn.com the preparation of this article. newly recognized parasite in humans.14

COMPENDIUM 864 November 2004 Cryptosporidium Infections in Cats and Dogs CE 865

Sporozoite Trophozoite Excystation

Host Type I meront Ingestion Excystation epithelial cell Thick-walled Autoinfection oocyst Merozoite Thin-walled oocyst Exits body

Merozoite

Microgamont

Mature Immature Type II meront oocyst oocyst

Macrogamont

Figure 1. Life cycle of Cryptosporidium spp. (Adapted from Dubey JP,Speer CA, Fayer R: Cryptosporidiosis of Man and Animals. Boca Raton, FL, CRC Press, 1990)

LIFE CYCLE mont) produces nonflagellated microgametes. In the Sporulated oocysts are ingested via direct contact with female stage (i.e., macrogamont), fertilization occurs and the feces of an infected host or contaminated or oocysts are produced. Two types of oocysts are produced, (Figure 1). The oocysts excyst in the digestive both of which sporulate endogenously and contain four tract, and the sporozoites penetrate the microvilli of a sporozoites, an oocyst residuum, and no sporocysts. variety of epithelial cells. The location of the infected Thin-walled oocysts are autoinfective. Thick-walled host cells depends on the species of Cryptosporidium. The oocysts are excreted in the feces.5,11,14 elongated sporozoite rounds up and becomes a tropho- Cryptosporidium spp contain approximately 5,000 zoite. The trophozoite becomes a multinucleated type I members, including (), Toxoplasma, schizont and produces eight type I merozoites, which , , , and spp. Most are penetrate other microvilli and become type II schizonts. obligate intracellular parasites. Apicomplexans lack Type II schizonts repeat this developmental cycle, result- appendages for locomotion and instead move by a “glid- ing in four type II merozoites. Recycling of asexual ing” motion. Cell entry by this group is mechanically stages may occur. Type II merozoites penetrate microvilli distinct from uptake of viruses, bacteria, and other para- and become sexual stages. The male stage (i.e., microga- sites. Cryptosporidium, Eimeria, and Toxoplasma spp

November 2004 COMPENDIUM 866 CE Cryptosporidium Infections in Cats and Dogs

form oocysts that are shed in the feces of infected hosts. Dogs Cryptosporidia oocysts are very resistant to environ- Most reported cases of cryptosporidiosis in dogs in- mental damage, chlorination, and standard cleansers. volve young animals.13,28–33 Cases in adult dogs are rare.34 This makes Cryptosporidium spp an important food- Clinical signs can vary from none to chronic or inter- and waterborne . Extreme temperatures and mittent diarrhea and wasting. Immunosuppression due prolonged contact with ammonia destroy the oocysts. to canine distemper may exacerbate infections in dogs.29,31 Concurrent canine parvovirus and PATHOGENESIS intestinal spp infection may also enhance cryp- The mechanisms by which Cryptosporidium spp tosporidiosis in immunosuppressed dogs.13,32 Two recent induce diarrhea, , and wasting in humans reports used molecular methods to determine the Cryp- and animals are not well understood.15 Cryptosporidial tosporidium spp in a fatal case involving an 8-week-old parasites can develop in a variety of epithelial cells in the Yorkshire terrier from Georgia33 and a nonfatal case in- body, not just in enterocytes in the intestines. This can volving a 9-week-old bullmastiff from Australia,13 and lead to respiratory, ocular, pancreatic, and hepatic infec- both reports found that C. canis organisms were present. tions in humans; fortunately, these extraintestinal loci of cryptosporidial infection have not been reported in dogs DIAGNOSIS or cats. Cryptosporidia develop in the microvillous bor- The small size of Cryptosporidium oocysts makes them der and displace it, eventually leading to loss of mature difficult to detect. Oocysts are often overlooked unless

Oocysts of C. felis and C. canis are structurally similar to the well-known and zoonotic C. parvum. surface .15 This causes shortening and fusion an examiner is specifically looking for them, and this is of villi and lengthening of the crypts due to acceleration especially true if few oocysts are present in the sample. of cell division to compensate for loss of cells.15 This Fecal flotation techniques used routinely in veterinary causes reduced uptake of fluids, electrolytes, and nutri- are adequate to demonstrate Cryptospori- ents from the gut lumen.15 dium oocysts if large numbers are present. The slide The minimum infective dose of Cryptosporidium oocysts should be examined using the high-power objective. for cats and dogs is unknown. Experimental studies in Sheather’s solution is the best flotation medium.3 humans using C. parvum oocysts collected from calves Because oocysts are small, they float in a plane higher indicate that 10 or fewer oocysts can cause infection.16 than that of helminth ova and other protozoal cysts. Differences in infectivity among different C. parvum iso- They are light pink, and a central residual body is usu- lates in human volunteers have been documented.15 ally visible in Cryptosporidium oocysts in fecal flotations. C. felis oocysts are smaller9,17,35 than those of C. parvum, CLINICAL SIGNS but morphology alone cannot be used to determine the Cats species of Cryptosporidium in a sample.36 Many small Most cats that are excreting Cryptosporidium oocysts animal technicians are not taught to recognize Cryp- do not have clinical signs.5,7,17–20 Young17,18 or immuno- tosporidium oocysts and may have difficulty identifying compromised18,21 animals are more likely to be infected. them when the tests are run only infrequently. In these Chronic or intermittent diarrhea, anorexia, and wasting cases, it is probably better for samples to be sent to diag- are common clinical signs in symptomatic cats.21–25 nostic reference laboratories for testing. Coinfection with Giardia spp or Tritrichomonas foetus Fecal samples sent to diagnostic laboratories can be may exacerbate clinical signs of cryptosporidiosis in tested using a number of procedures.37 More than 10 dif- cats.26,27 Administering (10 mg/kg/day SC ferent types of staining methods have been developed for for 4 to 9 days7 or 2.8 to 3.8 mg/kg/day PO for 26 use with fecal smears to aid in detecting Cryptosporidium days27) may cause oocysts to reappear in feline feces. oocysts via standard light .37 The Ziehl-Neelsen

COMPENDIUM November 2004 868 CE Cryptosporidium Infections in Cats and Dogs

Table 1. Transmission Studies with C. felis and C. canis Oocysts

Source Recipient Results Study Cat Guinea pigs Negative Iseki5, Arai et al17 Cat Mice Negative Iseki5, Arai et al17 Cat Newborn mice Negative Mtambo et al8, Arai et al17 Cat Lambs Positive Mtambo et al8 Cat Immunosuppressed mice Negative Mtambo et al8 Cat Rats Negative Arai et al17 Cat Dogs Negative Arai et al17 Dog Newborn mice Negative Fayer et al11 Dog Immunosuppressed mice Negative Fayer et al11 Dog Calves Positive Fayer et al11

Table 2. Prevalence of Cryptosporidium spp in Cats

Number Prevalence Examined Location Test (%) Study 600 United States Serology 8.3 McReynolds et al50 418 Australia Fecal 0 McGlade et al52 40 Australia PCR 10 McGlade et al52 102 Australia Fecal 1.2 Sargent et al9 10 France Fecal 0 Chermette and Blondel53 300 Germany Fecal 1.3 Augustin-Bichl55 13 Japan Fecal 38.5 Iseki5 507 Japan Fecal 20 Uga et al54 608 Japan Fecal 3.8 Arai et al17 57 Scotland Fecal 12.3 Nash et al19 235 Scotland Fecal 8.1 Mtambo et al18 205 Fecal 5.4 Hill et al51 263 New York Fecal 3.8 Spain et al20 acid-fast staining technique is most often used and produces red-stained oocysts against a blue–green background of fecal material. Fluorescently labeled mono- clonal to the oocyst stage of C. parvum have been made and are used in a commercial direct immunofluorescent (IFA) test.38 Most Cryp- tosporidium spp, including C. felis and C. canis, cross-react in commercial IFA- based diagnostic tests developed to detect C. parvum.39,40 Cross-reactivity also occurs in many for C. parvum.38 Polymerase chain reaction (PCR) can detect Cryptosporidium spp in fecal samples, and PCR is more sensitive than IFA testing.41 Most PCR-based tests indicate only the presence of Cryptospori- dium spp, but a recently developed set of PCR tests can differentiate between C. felis, C. canis, C. parvum, and C. hominis.42

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TREATMENT Table 3. Prevalence of Cryptosporidium spp in Dogs Chemotherapy for Cryptosporidium Number Prevalence infections in animals and humans has Examined Location Test (%) Study been actively investigated over the past 62 two decades (see box on page 871). 421 Australia Fecal/PCR 0 Bugg et al Over 100 compounds have been tested 493 Australia Fecal 11 Johnston and Gasser65 in animal models, but none 195 Australia Fecal 7.1 Milstein and 66 is highly effective clinically.43 Paro- Goldsmith momycin44 and (NTZ)27 25 Egypt Fecal 12 El-Hohary and 67 are compounds that have shown some Abdel-Latif 68 efficacy in animal models and have 57 Finland Fecal 0 Pohjola also been used to treat intestinal cryp- 29 France Fecal 44.8 Chermette and 53 tosporidiosis in cats. Treatment with Blondel 55 (165 mg/kg PO bid for 200 Germany Fecal 0 Augustin-Bichl et al 5 days) resulted in resolution of diar- 213 Japan Fecal 1.4 Uga et al54 rhea and disappearance of oocysts 140 Japan PCR 9.3 Abe et al63 from the feces of a 6-month-old cat 257 Korea Fecal 9.7 Kim et al40 with persistent diarrhea.44 Paro- 81 Spain Fecal 7.4 Causape et al61 momycin is potentially nephrotoxic, 101 Scotland Fecal 0 Simpson et al59 and acute renal failure was reported in 100 Scotland Fecal 1 Grimason et al69 four cats that received paromomycin 200 California Fecal 2 el-Ahraf et al60 for cryptosporidiosis or trichomonia- 130 Colorado Fecal 3.8 Hackett and Lappin64 sis.45 Treatment using NTZ (25 mg/kg 49 Georgia Fecal 10.2 Jafri et al70 PO bid for 28 days) eliminated Cryp- 100 Kentucky Fecal 17 Juett et al71 tosporidium oocysts from the feces of naturally infected laboratory cats. Use of NTZ was associated with and the presence of dark brown–black, foul-smelling However, additional well-controlled PCR-based and diarrhea while treating these cats.27 (0.5 PCR species–validated transmission studies need to be to 1.5 mg SC once daily) was given to alleviate vomiting conducted before these earlier observations can be com- in NTZ-treated cats.27 Fenbendazole administered at 50 pletely accepted. C. felis was not infectious in dogs or lab- mg/kg PO for 5 days did not affect Cryptosporidium oratory rodents in a limited number of studies. It is infec- oocyst excretion in cats.26 tious in lambs8 and has been found in a naturally infected Treatment of an 18-month-old cat with inflammatory cow.35 C. canis is not infectious in laboratory rodents but bowel disease and Cryptosporidium infection was suc- is mildly infectious in calves.11 The infectivity of C. canis cessful using a course of (25 mg/kg/day oocysts in cats has not been examined. C. parvum oocysts [three-fourths of the total dose was administered in the are moderately infectious in cats and dogs.3,11 Molecularly morning and one-fourth of the total dose at night] PO confirmed natural cases of C. parvum or C. hominis have for 60 days) and then tylosin (11 mg/kg PO bid with not been reported in cats or dogs. food for 28 days).15 Interpretation of these results was Several studies have suggested that humans have been hampered because of the presence of Clostridium per- infected with Cryptosporidium spp from kittens or fringens in the cat’s intestinal tract. Clindamycin admin- cats.46–48 None of these studies conducted genotyping or istered at 15 mg/kg PO q8h for 6 days did not eliminate other studies, and they should be viewed as only circum- Cryptosporidium oocysts from a 5-year-old pointer.34 stantially incriminating cats in the transmission of Cryptosporidium spp to humans. STUDIES ON HOST SPECIFICITY OF One study indicated that a veterinary student caring C. FELIS AND C. CANIS for an adult dog with cryptosporidiosis developed cryp- Transmission studies with C. felis and C. canis indicate tosporidiosis.34 The parasite in the dog or the veterinary that these species are relatively host-specific (Table 1). student was not genotyped or further characterized.

November 2004 COMPENDIUM 870 CE Cryptosporidium Infections in Cats and Dogs

Table 4. Reports of C. felis, C. canis, C. parvum, and C. hominis in Humans Who Tested Positive for Oocystsa

Percentage with Number and Type of Patients C. felis C. canis C. parvum C. hominis Study 30 with HIV 30% 10% 10% 50% Pieniazek et al72 22 with HIV 27% 0% 32% 9% Morgan et al73 1 with HIV 100% NA NA NA Caccio et al74 34 with HIV 9% 6% 15% 50% Gatei et al75 25 with HIV 4% 0% 56% 32% Alves et al76 80 childrenb 1% 3% 10% 84% Xiao et al77 1,680 (mixed) <1% <1% NR NR Pedraza-Diaz et al78 57 (mixed) 11% 0% 51% 32% Guyot et al79 1,075 (mixed) 0% 0% 62% 38% McLauchlin et al80 39 (mixed) 0% 0% 87% 13% Lowery et al81 102 (mixed) 0% 0% 14% 86% Gasser et al82 63 (mixed) 0% 0% 22% 75% Gatei et al83 22 (mixed) 0% 0% 14% 73% Yagita et al84 11 (mixed) 0% 0% 0% 36% Ong et al85 26 (mixed) 0% 0% 35% 58% Sinclair et al86 12 (mixed) 0% 0% 100% 0% Fretz et al87 aPercentages may not equal 100% because of the presence of other Cryptosporidium spp not listed. bFrom Lima, Peru. NA = not applicable; NR = not reported.

One study in patients with AIDS addressed the issue of erally considered nonspecific for coccidial parasites.58 Preva- pet-to-human transmission of Cryptosporidium infection.49 lence studies conducted to date with cats have not used The study found that patients with AIDS who owned cats molecular methods to determine the actual species of Cryp- or dogs were not at significantly higher risk of acquiring tosporidium found in cats. Therefore, the real prevalence of cryptosporidiosis than were patients with AIDS who did C. felis versus C. parvum or other Cryptosporidium spp in not own pets. Further critically controlled studies are cats is unknown. This information is important because C. needed to determine the importance of cats and dogs as felis has a more narrow host range than C. parvum. sources of Cryptosporidium infection in humans. PREVALENCE IN DOGS PREVALENCE IN CATS Fecal-, PCR-, and serologic-based surveys indicate Fecal-, PCR-, and serologic-based surveys indicate that that up to 44.8% of dogs examined have been exposed up to 38.5% of cats examined have been exposed to or are to or are excreting Cryptosporidium oocysts (Table excreting Cryptosporidium oocysts (Table 2).5,9,17–20,50–55 One 3).40,53–55,59–71 One PCR-based study from Japan indi- hundred litters of kittens from Germany were examined for cated that all 13 positive samples of 140 tested were C. Cryptosporidium infection, which was found in 4.3% of 70 canis.63 Two clinical cases in puppies have been attrib- litters that were kept outdoors and 3.3% of 30 litters kept uted to C. canis.13,33 The prevalence of C. parvum or indoors.56 One serologic study not listed in Table 1 indi- other Cryptosporidium spp in dogs is unknown. cated that 192 (74%) of 258 cats tested positive for IgG antibody via IFA testing.57 The results are questionable: PREVALENCE OF C. FELIS AND C. CANIS Interpretation of the IFA tests may have been flawed IN HUMANS because positive apical fluorescence was considered an indi- Most studies on the prevalence of C. felis and C. canis cator of a true positive reaction. Apical fluorescence is gen- in humans have been conducted in HIV-infected hu-

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On the Horizona Resources The sequence for C. parvum has recently been avma.org/noah/resources/zoonosis/crypto.asp generated. C. parvum lacks many typical metabolic (password protected) pathways, including Krebs cycle and de novo synthesis The AVMA Network of Animal Health provides of amino acids and nucleotides. In addition, zoonosis updates. Cryptosporidium spp contain many plant-like enzymes that are absent or very different from those usually found vin.com (password protected) in mammals. Further analysis of this genome could Search “cryptosporidiosis” photographs: Kirsten Vance’s provide important clues in developing an effective drug Arthropod and slide show against this parasite. Lindsay D: Proc West Vet Conf: Giardia and aAbrahamsen et al: Science 304:441, 2004. Cryptosporidia: Really Zoonotic

mans,72–76 children,77 or humans with cryptosporidiosis zoonotic potential. The contribution of canine and and some underlying immunosuppressive conditions78–87 feline Cryptosporidium spp to clinical disease in pets (Table 4). The prevalence of C. felis and C. canis in hu- does not seem to be great at this time but may be under- mans is less than that of C. hominis and C. parvum. Some estimated because so few cats and dogs are tested for studies have not found C. felis or C. canis in humans. infection. In contrast, the risk of zoonotic infection has received considerably more attention. Many practicing PREVALENCE OF CRYPTOSPORIDIUM veterinarians are unaware that, to minimize exposure to SPECIES IN THE ENVIRONMENT Cryptosporidium spp, current guidelines from the US Cryptosporidium oocysts are common in the environ- Public Health Service and Infectious Society ment and have been found in surveys of nondrinking of America recommend that HIV-infected humans surface and waste .88–91 However, genotyping should not take into their homes stray dogs or cats, ani- Cryptosporidium isolates from nondrinking water sources mals with diarrhea, or dogs and cats younger than 6 indicates little contamination by C. felis or C. canis.90 months of age.99 They further recommend that if a dog

Clinical signs of Cryptosporidium infection in cats and dogs vary from none to chronic or intermittent diarrhea.

One study documented C. felis or C. canis oocysts in raw or cat younger than 6 months of age is acquired by an waste water but found none in raw surface water.90 HIV-infected person, the animal should be tested for Although major outbreaks of human cryptosporidiosis Cryptosporidium spp. These recommendations, dating have been linked to contaminated ,92–95 from 1999, may be more stringent than necessary, but molecular studies indicate that C. hominis 96–98 and C. further molecular analysis of human and animal infec- parvum96,98 have been responsible for drinking water– tions is needed to realistically assess potential transmis- associated outbreaks of human cryptosporidiosis. No sion from pets to humans. Until more is known, practi- reports indicate that C. felis or C. canis has been associ- tioners should recognize that Cryptosporidium infection ated with waterborne outbreaks of human disease. in dogs and cats is not uncommon in North America and that zoonotic transmission from pets could cause CONCLUSION serious disease in immunocompromised humans. Despite extensive experimental and epidemiologic lit- erature on Cryptosporidium spp, the primary species REFERENCES 1. Fayer R, Ungar BL: Cryptosporidium spp and cryptosporidiosis. Microbiol Rev infecting dogs and cats, C. canis and C. felis, respectively, 50:458–483, 1986. have been identified only recently, and there is little 2. Carreno RA, Martin DS, Barta JR: Cryptosporidium is more closely related to experimental work documenting their pathogenicity or the gregarines than to coccidia as shown by phylogenetic analysis of apicom-

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plexan parasites inferred using small-subunit ribosomal RNA gene sequences. ment of Giardia infection in cats concurrently infected with Cryptosporidium Parasitol Res 85:899–904, 1999. parvum. Am J Vet Res 64:1027–1029, 2003. 3. Current WL, Reese NC, Ernst JV, et al: Human cryptosporidiosis in 27. Gookin JL, Levy MG, Law JM, et al: Experimental infection of cats with immunocompetent and immunodeficient persons. Studies of an outbreak and Tritrichomonas foetus. Am J Vet Res 62:1690–1697, 2001. experimental transmission. N Engl J Med 308:1252–1257, 1983. 28. Wilson RB, Holscher MA, Lyle SJ: Cryptosporidiosis in a pup. JAVMA 4. Tzipori S, Angus KW, Campbell I, Gray EW: Cryptosporidium: Evidence for 183:1005–1006, 1983. a single-species genus. Infect Immunol 30:884–886, 1980. 29. Fukushima K, Helman RG: Cryptosporidiosis in a pup with distemper. Vet 5. Iseki M: Cryptosporidium felis sp. N. (Protozoa: ) from the Pathol 21:247–248, 1984. domestic cat. Jpn J Parasitol 28:285–307, 1979. 30. Sisk DB, Gosser HS, Styer EL, Branch LO: Intestinal cryptosporidiosis in 6. Morgan UM, Monis PT, Fayer R, et al: Phylogenetic relationships among two pups. JAVMA 184:835–836, 1984. isolates of Cryptosporidium: Evidence for several new species. J Parasitol 85:1126–1133, 1999. 31. Turnwald GH, Barta O, Taylor HW, et al: Cryptosporidiosis associated with immunosuppression attributable to distemper in a pup. JAVMA 192:79–81, 7. Asahi H, Koyama T, Arai H, et al: Biological nature of Cryptosporidium sp. 1988. isolated from a cat. Parasitol Res 77:237–240, 1991. 32. Willard MD, Bouley D: Cryptosporidiosis, , and total colonic 8. Mtambo MM, Wright E, Nash AS, Blewett DA: Infectivity of a Cryp- mucosal collapse in an immunosuppressed puppy. JAAHA 35:405–409, 1999. tosporidium species isolated from a domestic cat (Felis domestica) in lambs and mice. Res Vet Sci 60:61–64, 1996. 33. Miller DL, Liggett A, Radi ZA, Branch LO: Gastrointestinal cryp- tosporidiosis in a puppy. 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Barr SC, Jamrosz GF, Hornbuckle WE, et al: Use of paromomycin for treat- feline leukemia virus–positive cat. JAVMA 191:705–706, 1987. ment of cryptosporidiosis in a cat. Am Vet Med Assoc 205:1742–1743, 1994. 22. Poonacha KB, Pippin C: Intestinal cryptosporidiosis in a cat. Vet Pathol 45. Gookin JL, Riviere JE, Gilger BC, Papich MG: Acute renal failure in four 19:139–195, 1982. cats treated with paromomycin. JAVMA 215:1806, 1821–1823, 1999. 23. Bennett M, Baxby D, Blundell N, et al: Cryptosporidiosis in the domestic 46. Koch KL, Shankey TV, Weinstein GS, et al: Cryptosporidiosis in a patient cat. Vet Rec 116:73–74, 1985. with hemophilia, common variable hypogammaglobulinemia, and the acquired syndrome. Ann Intern Med 99:337–340, 1983. 24. Lappin MR, Dowers K, Edsell D, et al: Cryptosporidiosis and inflammatory bowel disease in a cat. Feline Pract 3:10–13, 1997. 47. Lewis IJ, Hart CA, Baxby D: Diarrhoea due to Cryptosporidium in acute lym- phoblastic leukemia. Arch Dis Child 60:60–62, 1985. 25. Brown RR, Elston TH, Evans L, et al: American association of feline practi- tioners panel report on feline zoonoses. Compend Contin Educ Pract Vet 48. Egger M, Nguyen XM, Schaad UB, Krech T: Intestinal cryptosporidiosis 25:936–965, 2003. acquired from a cat. Infection 18:177–178, 1990. 26. Keith CL, Radecki SV, Lappin MR: Evaluation of fenbendazole for treat- 49. Glaser CA, Safrin S, Reingold A, Newman TB: Association between Cryp-

COMPENDIUM November 2004 Cryptosporidium Infections in Cats and Dogs CE 873

tosporidium infection and animal exposure in HIV-infected individuals. J biol 38:1180–1183, 2000. Acquir Immune Defic Syndr Hum Retroviral 17:79–82, 1998. 74. Caccio S, Pinter E, Fantini R, et al: Human infection with Cryptosporidium 50. McReynolds CA, Lappin MR, Ungar B, et al: Regional seroprevalence of felis: Case report and literature review. Emerg Infect Dis 8:85–86, 2002. Cryptosporidium parvum–specific IgG of cats in the United States. Vet Para- 75. Gatei W, Suputtamongkol Y, Waywa D, et al: Zoonotic species of sitol 80:187–195, 1999. Cryp- tosporidium are as prevalent as the anthroponotic in HIV-infected patients in 51. Hill SL, Cheney JM, Taton-Allen GF, et al: Prevalence of enteric zoonotic Thailand. Ann Trop Med Parasitol 96:797–802, 2002. organisms in cats. JAVMA 216:687–692, 2000. 76. Alves M, Matos O, Pereira Da Fonseca I, et al: Multilocus genotyping of 52. 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Dubey JP, Lindsay DS: A review of Neospora caninum and neosporosis. Vet 2000. Parasitol 67:1–59, 1996. 59. Simpson JW, Burnie AG, Miles RS, et al: Prevalence of Giardia and Cryp- 81. Lowery CJ, Millar BC, Moore JE, et al: Molecular genotyping of human tosporidium infection in dogs in Edinburgh. Vet Rec 123:445, 1988. cryptosporidiosis in Northern : Epidemiological aspects and review. Ir J Med Sci 170:246–250, 2001. 60. el-Ahraf A, Tacal Jr JV, Sobih M, et al: Prevalence of cryptosporidiosis in dogs and human beings in San Bernardino County, California. JAVMA 82. Gasser RB, El-Osta YG, Chalmers RM: Electrophoretic analysis of genetic 198:631–634, 1991. variability within Cryptosporidium parvum from imported and autochthonous cases of human cryptosporidiosis in the United Kingdom. Appl Environ 61. Causape AC, Quilez J, Sanchez-Acedo C, et al: Prevalence of intestinal para- Microbiol 69:2719–2730, 2003. sites, including Cryptosporidium parvum, in dogs in Zaragoza city, Spain. 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Johnston J, Gasser RB: Copro-parasitological survey of dogs in southern Vic- sporadic cryptosporidiosis cases: First report of human infections with a toria. Aust Vet Pract 23:127–131, 1993. cervine genotype. Emerg Infect Dis 8:263–268, 2002. 66. Milstein TC, Goldsmith JM: The presence of Giardia and other zoonotic 86. Sinclair M, Gasser RB, el-Osta A, et al: Genotyping of human Cryptosporid- parasites of urban dogs in Hobart, Tasmania. Aust Vet J 72:154–155, 1995. ium infections in Australia. 14:S119, 2003. 67. El-Hohary AH, Abdel-Latif AM: Zoonotic importance of cryptosporidiosis 87. Fretz R, Svoboda P, Ryan UM, et al: Genotyping of Cryptosporidium spp. iso- among some animals at Gharbia Province in Egypt. Indian J Anim Sci lated from human stool samples in Switzerland. Epidemiol Infect 68:305–307, 1998. 131:663–667, 2003. 68. Pohjola S: Survey of cryptosporidiosis in feces of normal healthy dogs. Nord 88. Lowery CJ, Moore JE, Millar BC, et al: Occurrence and molecular genotyp- Vet Med 36:189–190, 1984. ing of Cryptosporidium spp. in surface waters in Northern Ireland. J Appl 69. Grimason AM, Smith HV, Parker JFW, et al: Occurrence of Giardia sp. cysts Microbiol 91:774–779, 2001. and Cryptosporidium sp. oocysts in feces from Public Parks in the west of 89. Xiao L, Alderisio K, Limor J, et al: Identification of species and sources of Scotland. Epidemiol Infect 110:641–645, 1993. Cryptosporidium oocysts in storm waters with a small-subunit rRNA-based 70. Jafri H, Moorhead AR, Reedy T, et al: Detection of pathogenic protozoa in diagnostic and genotyping tool. Appl Environ Microbiol 66:5492–5498, 2000. fecal specimens from urban dwelling dogs. Am J Trop Med Hyg 49:S269, 90. Xiao L, Singh A, Limor J, et al: Molecular characterization of Cryptosporid- 1993. ium oocysts in samples of raw surface water and wastewater. Appl Environ 71. 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November 2004 COMPENDIUM 874 CE Cryptosporidium Infections in Cats and Dogs

93. Hayes EB, Matte TD, O’Brien TR, et al: Large community outbreak of cryp- 4. NTZ therapy for cryptosporidiosis in cats has tosporidiosis due to contamination of a filtered public . N Engl J been associated with Med 320:1372–1376, 1989. a. vomiting. 94. Atherton F, Newman CP, Casemore DP: An outbreak of waterborne cryp- tosporidiosis associated with a public water supply in the UK. Epidemiol Infect b. pneumonia. 115:123–131, 1995. c. kidney failure. 95. Goldstein ST, Juranek DD, Ravenholt O, et al: Cryptosporidiosis: An out- d. liver failure. break associated with drinking water despite state-of-the-art water treatment. Ann Intern Med 124:459–468, 1996. 96. Patel S, Pedraza-Diaz S, McLauchlin J, Casemore DP: Molecular characteri- 5. What is the best fecal flotation medium for find- zation of Cryptosporidium parvum from two large suspected waterborne out- ing Cryptosporidium oocysts? breaks. Commun Dis Public Health 1:231–233, 1998. a. zinc sulfate solution 97. Dalle F, Roz P, Dautin G, et al: Molecular characterization of isolates of b. Sheather’s sugar solution waterborne Cryptosporidium spp. collected during an outbreak of gastroen- teritis in South Burgundy, France. J Clin Microbiol 41:2690–2693, 2003. c. saturated solution d. sugar–salt solution 98. Glaberman S, Moore JE, Lowery CJ, et al: Three drinking-water-associated cryptosporidiosis outbreaks, Northern Ireland. Emerg Infect Dis 8:631–633, 2002. 6. Because Cryptosporidium oocysts are small, they 99. 1999 USPHS/IDSA Guidelines for the Prevention of Opportunistic Infec- tion in Persons Infected with Human Immunodeficiency Virus. MMWR a. float in a plane higher than that of helminth ova and 48(RR-10), 1999. (www.cdc.gov/mmwr/preview/mmwrhtml/rr4810a1.htm) other protozoal cysts. b. can be seen only by using oil immersion. c. look like Isospora spp. ARTICLE #3 CE TEST d. look like Giardia cysts. This article qualifies for 2 contact hours of continuing CE education credit from the Auburn University College of 7. Administering ______may cause oocysts to Veterinary Medicine. Subscribers who wish to apply this reappear in cat feces. credit to fulfill state relicensure requirements should consult a. NTZ their respective state authorities regarding the applicability b. paromomycin of this program. To participate, fill out the test form inserted c. clindamycin at the end of this issue. To take CE tests online and get real- d. prednisolone time scores, log on to www.VetLearn.com. 8. Developmental stages of Cryptosporidium spp can 1. Which Cryptosporidium spp was, until recently, be found in a host cell’s believed to be responsible for all cases of cryp- a. nucleus. tosporidiosis in humans and other mammals? b. microvilli. a. C. hominis c. cytoplasm. c. C. felis d. neurons. b. C. canis d. C. parvum 9. Immunofluorescent detection tests for Crypto- sporidium oocysts 2. Waterborne outbreaks of cryptosporidiosis have a. are not reliable. been associated with b. cross-react with most Cryptosporidium spp. a. C. parvum and C. hominis. c. are highly specific for C. canis but not C. felis. b. C. felis and C. parvum. d. are highly specific for C. hominis but not C. felis. c. C. felis and C. canis. d. C. felis and C. hominis. 10. Lesions and subsequent clinical signs of cryp- tosporidiosis are associated with 3. Paromomycin therapy for cryptosporidiosis in a. reduced uptake of fluids, electrolytes, and nutrients cats has been associated with from the gut lumen. a. vomiting. b. hemorrhagic diarrhea due to invasive stages. b. diarrhea. c. excretory diarrhea due to parasite toxins. c. kidney failure. d. fatty diarrhea due to infection of the upper small d. liver failure. intestine.

COMPENDIUM November 2004