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  • Author or Editor: Michael G. Levy x
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Abstract

Objective—To identify the geographic distribution of babesiosis among dogs in the United States and determine, for dogs other than American Pit Bull Terriers (APBTs), whether infection was associated with a recent dog bite.

Design—Retrospective study.

Animals—150 dogs.

Procedure—Canine blood samples submitted to the North Carolina State University Vector-Borne Disease Diagnostic Laboratory between May 2000 and October 2003 for which results of a Babesia-specific polymerase chain reaction assay were positive were identified, and breed and geographic origin of dogs from which samples were obtained were recorded. History and hematologic abnormalities for dogs that were not APBTs were recorded, and possible associations with a recent dog bite were examined.

Results—Dogs positive for Babesia DNA were located in 29 states and 1 Canadian province (Ontario). Babesia gibsoni was the most commonly detected species, with B gibsoni DNA detected in blood samples from 131 of 144 (91%) dogs. Of the 131 dogs positive for B gibsoni DNA, 122 (93%) were APBTs. Of the 10 dogs positive for Babesia canis vogeli DNA, 6 were Greyhounds. In dogs other than APBTs, there was an association between having recently been bitten by another dog, particularly an APBT, and infection with B gibsoni.

Conclusions and Clinical Relevance—Results document an expansion of the known geographic range for babesiosis among dogs in the United States. Testing for babesiosis should be pursued in dogs with clinicopathologic abnormalities consistent with immunemediated hemolytic anemia or thrombocytopenia, particularly if there is a history of a recent dog bite. (J Am Vet Med Assoc 2005;227:942–947)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the optimum reaction conditions and detection limits of PCR assay for identification of Pentatrichomonas hominis in DNA extracted from canine feces.

Sample Population—DNA extracted from feces of 4 dogs with diarrhea from which trichomonads were observed, 81 dogs that had feces submitted to a diagnostic laboratory, and 19 dogs residing in a laboratory animal facility.

Procedures—Optimum reaction conditions and absolute and practical detection limits of 2 P hominis 18S species-specific primer pairs were determined by use of an in vitro cultivated canine isolate of P hominis in the presence and absence of canine feces. The optimized PCR assay was applied to amplification of P hominis 18S rRNA genes from DNA extracted from the feces of dogs.

Results—Under optimized conditions, a primer pair was identified as able to detect as few as 1 P hominis organism/180-mg fecal sample. The PCR assay identified P hominis in diarrheic feces of 4 dogs in which trichomonads were seen by light microscopy. The P hominis genes were not amplified from other fecal samples examined.

Conclusions and Clinical Relevance—Molecular identification of P hominis in feces of 4 dogs with trichomonosis and diarrhea reported here validates the identity of this species in such infections. Sensitive and specific PCR amplification of P hominis 18S rRNA genes from DNA extracted from feces will directly facilitate studies examining pathogenicity of this trichomonad and enable differentiation of P hominis from other known or novel species of trichomonads that may infect the gastrointestinal tract of dogs.

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in American Journal of Veterinary Research

Abstract

Objective—To determine whether infection with Tritrichomonas foetus causes diarrhea in specific pathogen-free or Cryptosporidium coinfected cats.

Animals—4 cats with subclinical cryptosporidiosis (group 1) and 4 specific-pathogen-free cats (group 2).

Procedure—Cats were infected orogastrically with an axenic culture of T foetus isolated from a kitten with diarrhea. Direct microscopy and protozoal culture of feces, fecal character, serial colonic mucosal biopsy specimens, and response to treatment with nitazoxanide (NTZ; group 1) or prednisolone (groups 1 and 2) were assessed.

Results—Infection with T foetus persisted in all cats for the entire 203-day study and resulted in diarrhea that resolved after 7 weeks. Group-1 cats had an earlier onset, more severe diarrhea, and increased number of trichomonads on direct fecal examination, compared with group-2 cats. Use of NTZ eliminated shedding of T foetus and Cryptosporidium oocysts, but diarrhea consisting of trichomonad-containing feces recurred when treatment was discontinued. Prednisolone did not have an effect on infection with T foetus but resulted in reappearance of Cryptosporidium oocysts in the feces of 2 of 4 cats. During necropsy, T foetus was isolated from contents of the ileum, cecum, and colon. Tritrichomonas foetus organisms and antigen were detected on surface epithelia and within superficial detritus of the cecal and colonic mucosa.

Conclusions and Clinical Relevance—After experimental inoculation in cats, T foetus organisms colonize the ileum, cecum, and colon, reside in close contact with the epithelium, and are associated with transient diarrhea that is exacerbated by coexisting cryptosporidiosis but not treatment with prednisolone. (Am J Vet Res 2001;62:1690–1697)

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in American Journal of Veterinary Research

Abstract

Objective—To determine the efficacy of tinidazole for treatment of cats with experimentally induced Tritrichomonas foetus infection.

Animals—8 specific-pathogen-free kittens.

Procedures—Tinidazole was tested for activity against a feline isolate of T foetus in vitro. Kittens were infected orogastrically with the same isolate and treated or not with tinidazole (30 mg/kg, PO, q 24 h for 14 days). Amoxicillin was administered 28 weeks after completion of tinidazole administration to induce diarrhea. Feces were repeatedly tested for T foetus by use of PCR assay and microbial culture for 33 weeks.

Results—Tinidazole killed T foetus at concentrations ≥ 10 μg/mL in vitro. In experimentally induced infection, tinidazole administered at 30 mg/kg decreased T foetus below the limit of molecular detection in 2 of 4 cats. Recrudescent shedding of T foetus, as elicited by amoxicillin-induced diarrhea, was diminished in cats that received prior treatment with tinidazole.

Conclusions and Clinical Relevance—Although tinidazole decreased the detection of T foetus and treated cats were resistant to later efforts to incite the infection, inability of tinidazole to eradicate infection in many cats poses a serious impediment to the drug’s effectiveness in practice.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the efficacy of and optimize a commercially available culture system for sensitive and specific in-clinic culture of Tritrichomonas foetus from cat feces.

Design—Prospective study.

Sample Population—Samples of freshly voided feces from 117 purebred cats and pure cultures of T foetus obtained from a cat with chronic diarrhea.

Procedure—Optimal conditions for use of the culture system, such as quantity of fecal inoculum (0.025 to 0.2 g) and cultivation temperature (25 or 37°C [98.6 or 77.0°F]), were determined. Specificity of the system was examined by attempted culture of Giardia lamblia and Pentatrichomonas hominis. Sensitivity of the system to detect T foetus was determined by inoculation of culture system pouches with serially diluted T foetus suspensions with and without feces.

Results—Detection limit of the culture system was 1 and 1,000 T foetus organisms without and with feces from cats, respectively. Optimal fecal inoculum was < 0.1 g of feces. At 37°C, cultures yielded positive results in 24 hours; organisms remained viable for 1 to 6 days, and bacterial overgrowth was common. At 25°C, cultures yielded positive results in 1 to 11 days; organisms were long-lived, and bacterial overgrowth was uncommon. Neither G lamblia or P hominis survived in the culture system.

Conclusions and Clinical Relevance—The culture system was sensitive and specific for culture of T foetus in feces of cats. Performance was optimal when test kits were inoculated with ≤ 0.1 g of freshly voided feces and cultured at 25°C. (J Am Vet Med Assoc 2003;222:1376–1379)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To describe the demographic and clinical characteristics of feline cytauxzoonosis in the midAtlantic states and compare the Cytauxzoon felis 18S rRNA gene sequences from affected cats with sequences reported from affected cats in other regions.

Design—Retrospective case series.

Animals—34 cats with C felis infection.

Procedure—Medical records of cats in which C felis infection was diagnosed from May 1998 through June 2004 were reviewed; data collected included signalment, month of diagnosis, geographic location, clinicopathologic abnormalities, medical treatments, outcome, and necropsy findings when applicable. Cytauxzoon felis DNA was amplified, cloned, and sequenced from 4 of these cats and compared with previously reported C felis DNA sequences.

Results—Of 34 C felis–infected cats, 28 resided in North Carolina, 3 resided in South Carolina, and 3 resided in Virginia; in 32 cats, a diagnosis of C felis infection was made in April through September. Pancytopenia and icterus were the most common clinicopathologic abnormalities. Thirty-two cats either died or were euthanatized, and 2 cats survived. At 5 veterinary hospitals, multiple cases were identified, and 4 multicat households had > 1 cat infected with C felis. The 18S rRNA gene sequences characterized in organisms obtained from 4 cats were nearly identical to C felis DNA sequences reported from other US regions.

Conclusions and Clinical Relevance—Data indicate that veterinarians in the mid-Atlantic region of the United States should consider C felis infection in cats that become ill with fever, icterus, and pancytopenia or bicytopenia, especially in the spring and summer months.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the long-term outcome of cats infected with Tritrichomonas foetus and identify treatment and management strategies influencing resolution of infection or associated diarrhea.

Design—Prospective study.

Sample Population—26 cats with T foetus-associated diarrhea at least 22 months prior to the study.

Procedure—A standardized survey regarding clinical course and management was administered to owners of cats with T foetus infection and associated diarrhea. Fecal samples were obtained from each cat; the presence of T foetus was assessed via microscopic examination of smears, culture in commercial media, and polymerase chain reaction amplification of T foetus rDNA involving species-specific primers.

Results—Survey responses were obtained from owners of all 26 cats. Twenty-three cats had complete resolution of diarrhea a median of 9 months after onset. Analysis of fecal samples obtained from 22 cats revealed persistent T foetus infection in 12, with a median of 39 months after resolution of diarrhea. History of implementation of a dietary change, treatment with paromomycin, or higher numbers of cats in the household was associated with significantly longer duration of time to resolution of diarrhea.

Conclusions and Clinical Relevance—Results suggested chronic T foetus-associated diarrhea in most cats is likely to resolve spontaneously within 2 years of onset. Chronic infection with T foetus(without clinical signs) after resolution of diarrhea appears to be common. Although often temporarily effective in decreasing severity of diarrhea, attempts to treat cats with T foetus infection may result in prolongation of time to resolution of diarrhea. (J Am Vet Med Assoc 2004;225:888–892)

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in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE To determine the seroprevalence of heartworm infection, risk factors for seropositivity, and frequency of prescribing heartworm preventives for cats.

DESIGN Prospective cross-sectional study.

ANIMALS 34,975 cats from 1,353 veterinary clinics (n = 26,707) and 125 animal shelters (8,268) in the United States and Canada.

PROCEDURES Blood samples were collected from all cats and tested with a point-of-care ELISA for Dirofilaria immitis antigen, FeLV antigen, and FIV antibody. Results were compared among geographic regions and various cat groupings.

RESULTS Seropositivity for heartworm antigen in cats was identified in 35 states but not in Canada; overall seroprevalence in the United States was 0.4%. Seroprevalence of heartworm infection was highest in the southern United States. A 3-fold increase in the proportion of seropositive cats was identified for those with (vs without) outdoor access, and a 2.5-fold increase was identified for cats that were unhealthy (vs healthy) when tested. Seroprevalence was 0.3% in healthy cats, 0.7% in cats with oral disease, 0.9% in cats with abscesses or bite wounds, and 1.0% in cats with respiratory disease. Coinfection with a retrovirus increased the risk of heartworm infection. Heartworm preventives were prescribed for only 12.6% of cats at testing, and prescribing was more common in regions with a higher seroprevalence.

CONCLUSIONS AND CLINICAL RELEVANCE At an estimated prevalence of 0.4%, hundreds of thousands of cats in the United States are likely infected with heartworms. Given the difficulty in diagnosing infection at all clinically relevant parasite stages and lack of curative treatment options, efforts should be increased to ensure all cats receive heartworm preventives.

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in Journal of the American Veterinary Medical Association