ABSTRACT
Intestinal helminths are common in dogs in the United States, particularly non-treated dogs in animal shelters, but surveys by fecal flotation may underestimate their prevalence. To determine the prevalence of intestinal helminths and evaluate the ability of fecal flotation and detection of nematode antigen to identify those infections, contents of the entire gastrointestinal tract of 97 adult (>1year) dogs previously identified for humane euthanasia at two animal control shelters in northeastern Oklahoma, USA, were screened. All helminths recovered were washed in saline and fixed prior to enumeration and identification to genus and species. Fecal samples from each dog were examined by passive sodium nitrate (SG 1.33) and centrifugal sugar solution (SG 1.25) flotation. Fecal antigen detection assays were used to confirm the presence of nematode antigen in frozen fecal samples from 92 dogs. Necropsy examination revealed Ancylostoma caninum in 45/97 (46.4%), Toxocara canis in 11/97 (11.3%), Trichuris vulpis in 38/97 (39.2%), Dipylidium caninum in 48/97 (49.5%), and Taenia sp. in 7/97 (7.2%) dogs. Passive fecal flotation identified 38/45 (84.4%) A. caninum, 6/11 (54.5%) T. canis, 26/38 (68.4%) T. vulpis, 2/48 (4.2%) D. caninum, and 1/7 (14.3%) Taenia sp. infections, while centrifugal flotation combined with antigen detection assays identified A. caninum in 97.7% (43/44), T. canis in 77.8% (7/9), and T. vulpis in 83.3% (30/36) of infected dogs based on necropsy recovery of nematodes. Taken together, these data indicate that detection of nematode antigen is a useful adjunct to microscopic examination of fecal samples for parasite eggs, and that this approach can improve diagnostic sensitivity for intestinal nematode infections in dogs.
Subject(s)
Antigens, Helminth/immunology , Dog Diseases/diagnosis , Helminthiasis, Animal/diagnosis , Helminths/immunology , Intestinal Diseases, Parasitic/veterinary , Ancylostoma/immunology , Ancylostoma/isolation & purification , Animals , Dog Diseases/epidemiology , Dog Diseases/parasitology , Dogs , Feces/parasitology , Helminthiasis, Animal/epidemiology , Helminthiasis, Animal/parasitology , Helminths/isolation & purification , Intestinal Diseases, Parasitic/diagnosis , Intestinal Diseases, Parasitic/epidemiology , Intestinal Diseases, Parasitic/parasitology , Intestines/parasitology , Oklahoma/epidemiology , Prevalence , Toxocara canis/immunology , Toxocara canis/isolation & purification , Trichuris/immunology , Trichuris/isolation & purificationABSTRACT
Objectives To determine whether pretreating diagnostic samples with heat increases the detection of Dirofilaria immitis antigen in adult cats, we evaluated feline serum and plasma samples collected in heartworm-endemic areas of the southern United States. Methods Commercial microtiter well assays for detection of D immitis antigen were used to evaluate serum or plasma samples from 385 shelter and free-roaming cats from the southcentral and southeastern United States before and after heat treatment; commercial antibody tests were performed on a subset of samples. Results Prior to sample heat treatment, 1/220 (0.5%) shelter cats and 4/165 (2.4%) free-roaming cats had detectable D immitis antigen. After heat pretreatment, the detection rate increased to 13/220 (5.9%) and 13/165 (7.9%), respectively. Antibody reactive to D immitis was significantly more common ( P <0.001) in the serum of cats that were antigen positive after heat treatment (10/13; 76.9%) than serum from cats that remained antigen negative after heat treatment (22/163; 13.5%). Conclusions and relevance Heat pretreatment of feline samples increased antigen detection by commercial assays for D immitis and improved overall concordance of antigen and antibody test results in antigen-positive samples in this population. Although further work to investigate the specificity of D immitis antigen assays when using pre-treated samples is warranted, this approach may be useful in the diagnosis of heartworm infection in individual cats and may increase the accuracy of surveys based on antigen detection.
Subject(s)
Antigens, Helminth/blood , Cat Diseases/parasitology , Dirofilaria immitis/isolation & purification , Dirofilariasis/diagnosis , Animals , Animals, Wild , Cat Diseases/blood , Cat Diseases/diagnosis , Cats , Dirofilaria immitis/immunology , Dirofilariasis/blood , Dirofilariasis/parasitology , Hot Temperature , Specimen Handling/methods , Specimen Handling/veterinaryABSTRACT
Fecal flotation is routinely used to identify feline helminth infections in clinical practice, but it is known to have limitations of sensitivity, particularly for cestodes. To determine the prevalence of helminths in a contemporary population of cats and evaluate the ability of fecal flotation to detect these infections, helminths were recovered from intestinal tracts removed from 116 adult cats humanely euthanized by an animal control shelter in northeastern Oklahoma. Results were compared to those of fecal flotation performed using both passive and centrifugal techniques. Helminths were identified in 78/116 (67.2%) cats, including Toxocara cati (48/116; 41.4%), Ancylostoma tubaeforme (8/116; 6.9%), Dipylidium caninum (40/116; 34.5%), and Taenia taeniaeformis (30/116; 25.9%). Cats with T. cati were significantly more likely to harbor T. taeniaeformis (P = .001) than cats without ascarids. Centrifugal fecal flotation with sugar solution identified 37/48 (77.1%) T. cati infections, 8/30 (26.7%) T. taeniaeformis infections, and no D. caninum infections. Proglottids were detected on external examination in 19.0% (12/63) of cats with cestodes. Cestodes were present in over half of the cats examined in this study, but the majority of these infections were not evident by the detection of external proglottids or recovery of characteristic stages on fecal flotation.
