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Starkey LA, Bowles JV, Blagburn BL. Comparison of acid- versus heat-treatment for immune complex dissociation and detection of Dirofilaria immitis antigen in canine plasma. Vet Parasitol 2020; 282:109134. [PMID: 32474295 DOI: 10.1016/j.vetpar.2020.109134] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 04/29/2020] [Accepted: 05/08/2020] [Indexed: 11/26/2022]
Abstract
Annual antigen testing is a mainstay for diagnosing infection with Dirofiliaria immitis in dogs; yet, it has been documented that some heartworm-infected dogs and cats test false-negative for antigen due to the presence of antigen-antibody complexes. Several studies have reported the use of heat as a reliable means of immune-complex dissociation (ICD) in recent years; however, the data regarding the use of acid as a reliable method of ICD for D. immitis detection are limited. The objective of this study was to compare an acid-based form of ICD to the more established and evaluated method of heat-based ICD in experimentally infected and non-infected dogs. Plasma from class A dogs experimentally infected ∼4 months prior with D. immitis (infected; n = 24) and dogs reared indoors with no history of exposure to mosquitoes (non-infected; n = 75) were evaluated for presence of D. immitis antigen (DiroCHEK® Heartworm antigen test kit). Each sample was divided into three aliquots for testing: [1] Control plasma (no acid- or heat-treatment), [2] acid-treated plasma (trichloroacetic acid (TCA), incubation, centrifugation for 5 min at 16,000 X g, buffer), and [3] heat-treated plasma (104 °C followed by centrifugation at 16,000 X g). Treatments for each aliquot were performed and tested in triplicate; results were determined both visually (color change) and by spectrophotometric analysis (optical density [OD] value). Of the 24 infected dogs, 0/24 tested positive for antigen in the absence of acid- or heat-treatment. Those same plasma samples following processing by either acid- or heat-treatment yielded 18/24 (75.0%) and 19/24 (79.2%) antigen-positive results, respectively. Of the 75 plasma samples from non-infected dogs, neither acid- nor heat-treatment of plasma caused any false-positive color changes or spectrophotometric values. These results indicate that acid as a means of ICD reliably allowed for the detection of D. immitis antigen in infected plasma while not inducing false-positive results in non-infected plasma samples.
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Affiliation(s)
- L A Starkey
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, 166 Greene Hall, Auburn, AL 36849, United States.
| | - J V Bowles
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, 166 Greene Hall, Auburn, AL 36849, United States
| | - B L Blagburn
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, 166 Greene Hall, Auburn, AL 36849, United States
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Rust MK, Blagburn BL, Denholm I, Dryden MW, Payne P, Hinkle NC, Kopp S, Williamson M. International Program to Monitor Cat Flea Populations for Susceptibility to Imidacloprid. J Med Entomol 2018; 55:1245-1253. [PMID: 29931332 DOI: 10.1093/jme/tjy092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Indexed: 06/08/2023]
Abstract
An international team of scientists and veterinarians was assembled in 1999 to develop a monitoring program to determine the susceptibility of cat fleas, Ctenocephalides felis felis (Bouché) (Siphonaptera: Pulicidae), to imidacloprid. Cat flea eggs were collected, shipped to laboratories, and tested for their susceptibility to imidacloprid. Over 3,000 C. felis populations were collected from 2002 to 2017 from 10 different countries. Of these, 66.3% were collected from cats and 33.7% from dogs. C. f. felis populations (n = 2,200) were bioassayed by exposing cat flea eggs and the emerging larvae to a Diagnostic Dose (DD) of 3 ppm imidacloprid in larval rearing medium. Flea eggs hatched and developed in the untreated controls in 1,837 of the isolates (83.5%) bioassayed. Flea isolates (n = 61) that had ≥5% survival at the DD of 3 ppm were retested with a second DD of 3 ppm. None of them had ≥5% survival to the second dose of 3 ppm. Of the 1,837 valid C. felis isolates tested, there has been no evidence of a decreased susceptibility to imidacloprid over the past 17 yr. The methods outlined in this article should provide an acceptable protocol for testing many of the new active ingredients that have been registered for cat flea control.
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Affiliation(s)
- M K Rust
- Department of Entomology, University of California, Riverside, CA
| | - B L Blagburn
- Department of Pathobiology, Auburn University, Auburn, AL
| | - I Denholm
- Plant and Invertebrate Ecology Division, Rothamsted Research, Harpenden, Hertfordshire, United Kingdom
| | - M W Dryden
- Department of Diagnostic Medicine, Kansas State University, Manhattan, KS
| | - P Payne
- Department of Diagnostic Medicine, Kansas State University, Manhattan, KS
| | - N C Hinkle
- Department of Entomology, University of Georgia, Athens, GA
| | - S Kopp
- School of Veterinary Science, University of Queensland, Gatton, QLD, Australia
| | - M Williamson
- Department of Biological and Ecological Chemistry, Rothamsted Research, Harpenden, United Kingdom
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Dillon AR, Blagburn BL, Tillson M, Brawner W, Welles B, Johnson C, Cattley R, Rynders P, Barney S. The progression of heartworm associated respiratory disease (HARD) in SPF cats 18 months after Dirofilaria immitis infection. Parasit Vectors 2017; 10:533. [PMID: 29143683 PMCID: PMC5688506 DOI: 10.1186/s13071-017-2425-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Heartworm-associated respiratory disease (HARD) in cats is induced by the arrival and death of immature adult Dirofilaria immitis in the pulmonary system and is indistinguishable from mature adult heartworm infection. METHODS A controlled, blind research study investigated the long-term (18 months post infection, PI) consequences of the inflammatory response associated with the death of immature adult heartworms in cats. Three groups of cats, 10 per group, were infected with 100 third-stage (L3) larvae by subcutaneous injection. Group A cats were treated with selamectin (Revolution®; Zoetis) per label directions at 28 days PI and once monthly for 17 months. Group B cats were treated orally with ivermectin (Ivomec®; Merial) at 150 μg/kg) at 70 days PI, then every 2 weeks for 15 months. Group C cats were untreated PI. At baseline (Day 0) and on Days 70, 110, 168, 240, 309, 380, and 505 PI, peripheral blood, serum, bronchial lavage, and thoracic radiographic images were collected. RESULTS The selamectin-treated cats (Group A) and ivermectin-treated cats (Group B) were free of heartworms or heartworm fragments at necropsy. All cats became heartworm antibody positive at some time point in the study except for one cat in Group A. Only cats in Group C (all with adult heartworms) were heartworm antigen positive. The heartworm antibody titer for Group B was highest on Days 110 to 168 and then decreased over time and 50% were serologically antibody negative on Day 240. Eosinophilic bronchoalveolar lavage (BAL) cytology and peripheral eosinophilia were most pronounced on Day 110 in all cats. Randomly distributed myofibrocytes in the lungs of some Group A cats suggest that precardiac larval stages were affecting the lungs. Radiographs in Group B cats demonstrated partial resolution of the initial HARD reaction but chronic myofibrocyte proliferation was histologically evident 18 months after infection. CONCLUSION HARD was induced by immature adult worm infection with progressive improvement starting 6 to 8 months after infection but histologic lesions were evident in some cats 18 months after infection. The serologic antibody assay was negative in 50% of cats at 8 months and 100% of cats at 18 months post infection. Abnormal radiographic lung patterns continued in a subset of Group B cats for months after heartworm antibody serology and BAL cytology returned to normal.
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Affiliation(s)
- A. Ray Dillon
- College of Veterinary Medicine, Auburn University, Auburn, Alabama 36849 USA
- Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, 1220 Wire Road, Auburn, Alabama 36849 USA
| | - Bryon L. Blagburn
- College of Veterinary Medicine, Auburn University, Auburn, Alabama 36849 USA
| | - Michael Tillson
- College of Veterinary Medicine, Auburn University, Auburn, Alabama 36849 USA
| | - William Brawner
- College of Veterinary Medicine, Auburn University, Auburn, Alabama 36849 USA
| | - Betsy Welles
- College of Veterinary Medicine, Auburn University, Auburn, Alabama 36849 USA
| | - Calvin Johnson
- College of Veterinary Medicine, Auburn University, Auburn, Alabama 36849 USA
| | - Russell Cattley
- College of Veterinary Medicine, Auburn University, Auburn, Alabama 36849 USA
| | - Pat Rynders
- College of Veterinary Medicine, Auburn University, Auburn, Alabama 36849 USA
| | - Sharron Barney
- College of Veterinary Medicine, Auburn University, Auburn, Alabama 36849 USA
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Rust MK, Denholm I, Dryden MW, Payne P, Blagburn BL, Jacobs DE, Bond R, Mencke N, Schroeder I, Weston S, Vaughn M, Coleman G, Kopp S. Large-scale monitoring of imidacloprid susceptibility in the cat flea, Ctenocephalides felis. Med Vet Entomol 2011; 25:1-6. [PMID: 21138459 DOI: 10.1111/j.1365-2915.2010.00934.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Although on-animal topical treatment with compounds such as imidacloprid has revolutionized the control of the cat flea, Ctenocephalides felis (Bouché) (Siphonaptera: Pulicidae), the development of insecticide resistance is a continuing threat. As part of a highly co-ordinated and unprecedented resistance monitoring programme for C. felis, 1437 flea isolates were collected by veterinary clinics in Australia, Germany, France, the U.K. and 29 states in the U.S.A. from 2002 to 2009. About 65% of the collections were made from June to October each year and 71% of the collections were from cats. Collections of flea eggs were sent to one of five different laboratories, where they were tested with a diagnostic dose of imidacloprid (3 p.p.m.) applied to larval flea-rearing medium. Of the 1437 collections received, 1064 contained adequate numbers of eggs for testing. Of these isolates, untreated eggs failed to hatch in 22.7% and were not considered valid bioassays. Survival rates >5% and development of adult fleas (a threshold for further testing) occurred in only 22 isolates. They were re-tested with the same diagnostic dose and none produced >5% adult emergence. Complete dose-response bioassays were performed on three of the isolates that had triggered a second test and produced slopes, intercepts and LC(50) values similar to those for existing susceptible laboratory strains. Results confirmed sustained susceptibility of C. felis to imidacloprid, despite its widespread use for over a decade.
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Affiliation(s)
- M K Rust
- Department of Entomology, University of California Riverside, Riverside, CA 92521-0314, USA.
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Marchiondo AA, Holdsworth PA, Green P, Blagburn BL, Jacobs DE. World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) guidelines for evaluating the efficacy of parasiticides for the treatment, prevention and control of flea and tick infestation on dogs and cats. Vet Parasitol 2006; 145:332-44. [PMID: 17140735 DOI: 10.1016/j.vetpar.2006.10.028] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Revised: 10/10/2006] [Accepted: 10/10/2006] [Indexed: 11/25/2022]
Abstract
These guidelines are intended to assist the planning and conduct of laboratory and clinical studies to assess the efficacy of ectoparasiticides applied to dogs or cats for the purpose of treating, preventing and controlling flea and tick infestations. The term ectoparasiticide includes insecticidal and acaricidal compounds, as well as insect growth regulators. The range of biological activities accruing from animal treatment that are considered include: repellency and anti-feeding effects, knockdown, speed of kill, immediate and persistent lethal effects, and interference with egg fertility and subsequent development of off-host life cycle stages. Information is provided on the selection of animals, dose determination, dose confirmation and field studies, record keeping, interpretation of results and animal welfare. These guidelines are also intended to assist registration authorities involved in the approval and registration of new parasiticides, and to facilitate the worldwide adoption of harmonized procedures.
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Affiliation(s)
- A A Marchiondo
- IVX Animal Health Inc., 3915 South 48th St. Terrace, St. Joseph, MO 64503-4711, United States of America.
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Rust MK, Denholm I, Dryden MW, Payne P, Blagburn BL, Jacobs DE, Mencke N, Schroeder I, Vaughn M, Mehlhorn H, Hinkle NC, Williamson M. Determining a diagnostic dose for imidacloprid susceptibility testing of field-collected isolates of cat fleas (Siphonaptera: Pulicidae). J Med Entomol 2005; 42:631-6. [PMID: 16119552 DOI: 10.1093/jmedent/42.4.631] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The susceptibility of four laboratory strains of cat fleas, Ctenocephalides felis (Bouche), to imidacloprid was determined by three different laboratories, by using a standardized bioassay protocol. The probit lines generated by the different laboratories were very similar, with LC50 values ranging from 0.32 to 0.81 ppm. Based on these data, a diagnostic dose (DD) of 3 ppm imidacloprid in larval rearing media was provisionally identified for detecting shifts in tolerance, possibly as a consequence of incipient imidacloprid resistance. None of the larvae from the susceptible laboratory strains survived the DD. Eighteen field-collected isolates were evaluated for their susceptibility to imidacloprid and to validate a DD of 3 ppm. Probit lines from 18 field-collected isolates were very similar, with LC50 values ranging from 0.14 to 1.52 ppm. When exposed to the DD, between 3 and 10% of the exposed larvae emerged as adults from only three of the 18 isolates. All other field isolates gave 100% mortality at the DD. Under the criteria established (>5% survivorship at 3 ppm), two isolates would be established on mammalian hosts and more extensive tests conducted to exclude or confirm the presence of resistance. The DD of 3 ppm is robust enough to eliminate most of the susceptible isolates collected until today, yet low enough to identify possible isolates for further testing.
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Affiliation(s)
- M K Rust
- Department of Entomology, University of California, Riverside, Riverside, CA 92521-0314, USA
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Billeter SA, Spencer JA, Chobotar B, Blagburn BL. Ponazuril inhibits the development of Eimeria vermiformis in experimentally infected outbred Swiss mice. Parasitol Res 2004; 95:172-5. [PMID: 15616859 DOI: 10.1007/s00436-004-1263-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2004] [Accepted: 09/23/2004] [Indexed: 12/01/2022]
Abstract
We evaluated a 15% paste formulation of ponazuril in outbred Swiss mice that were experimentally infected with Eimeria vermiformis. Thirty, 8-week-old female mice (approximately 20 g) were placed in one group of 10 mice and one group of 20 mice. Mice in both groups were gavaged with approximately 5,000 sporulated oocysts of E. vermiformis on day 0. Mice in group 2 (n=10) were treated orally on days 3 and 4 with ponazuril (suspended in 30% propylene glycol) at the rate of 20 mg/kg. Mice in group 1 (n=20) were gavaged with a similar volume of 30% propylene glycol. Rates of oocyst passage (oocysts/g feces) were determined on day 10 (peak patency) for treated and nontreated mice using a fecal aliquot oocyst counting technique. Oocysts were not observed in the feces of treated mice using the aliquot technique. Control mice passaged oocysts at a geometric mean rate of >104,000 oocysts/g feces. Control mice also produced significantly less feces on day 10. These results indicate that ponazuril is effective against E. vermiformis under the conditions utilized in this study, and that the E. vermiformis mouse model could be useful in predicting the efficacy of new anticoccidial drugs.
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Affiliation(s)
- S A Billeter
- College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA
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8
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Vobis M, D'Haese J, Mehlhorn H, Mencke N, Blagburn BL, Bond R, Denholm I, Dryden MW, Payne P, Rust MK, Schroeder I, Vaughn MB, Bledsoe D. Molecular phylogeny of isolates of Ctenocephalides felis and related species based on analysis of ITS1, ITS2 and mitochondrial 16S rDNA sequences and random binding primers. Parasitol Res 2004; 94:219-26. [PMID: 15340839 DOI: 10.1007/s00436-004-1201-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2004] [Accepted: 07/19/2004] [Indexed: 11/27/2022]
Abstract
The phylogenetic relationships among 31 different flea isolates representing seven different species were studied by nucleotide sequence comparison of the internal transcribed spacer 1 (ITS1), internal transcribed spacer 2 (ITS2) and/or mitochondrial 16S ribosomal RNA gene (mt16S-rDNA) to examine the patterns of variation. Results show that all regions are useful in discriminating among flea species. In Ctenocephalides felis and Tunga penetrans, some differences in these gene regions occurred among different isolates within the same species. In the latter case, the differences are in the mt16S-rDNA region, with one isolate showing 48% divergence in nucleotide sequence. The taxonomic implications of this result are unclear at present. The gene regions revealed differences between C. felis isolates only after DNA sequencing the PCR products. Further differentiation among C. felis isolates was obtained using four different random binding primers (decamers) and primers for mammalian aldolase to amplify narrow differences in the genome. Using these primers we were able to discriminate between different C. felis isolates and determine that some of the genetic variation coincided with minor differences in response to the control agent imidacloprid. However, overall findings do not support the existence of subspecies of C. felis.
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Affiliation(s)
- M Vobis
- Institute for Zoomorphology, Cell Biology und Parasitology, Heinrich-Heine University, 40225, Düsseldorf, Germany
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9
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Spencer JA, Joiner KS, Hilton CD, Dubey JP, Toivio-Kinnucan M, Minc JK, Blagburn BL. Disseminated Toxoplasmosis in a Captive Ring-Tailed Lemur (Lemur catta). J Parasitol 2004; 90:904-6. [PMID: 15357101 DOI: 10.1645/ge-249r] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
A 3-yr-old secundiparous female ring-tailed lemur presented to the Auburn University Small Animal Clinic with signs of dyspnea, lethargy, and anorexia. The animal died before she could be examined, and a full necropsy was immediately performed. Provisional necropsy findings included moderate pneumonia and hepatopathy. Acute interstitial pneumonia and focal hepatocellular necrosis were confirmed histologically. Lung impression smears, histopathology, electron microscopy, immunohistochemistry, and tissue culture isolation resulted in a diagnosis of acute disseminated Toxoplasma gondii infection, which was confirmed by polymerase chain reaction. The isolate of T. gondii was avirulent for mice and was named AU Tgl and genetically is type II. The source of the infection remains unclear, but speculation suggests contaminated fruit or blackbirds (Passeriformes: Icteridae) acting as transport hosts for oocysts from nondomestic felids and feral cats on the property.
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Affiliation(s)
- J A Spencer
- Department of Pathobiology, 122 Greene Hall, College of Veterinary Medicine, Auburn University, Auburn, Alabama 36849, USA.
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Schroeder I, Blagburn BL, Bledsoe DL, Bond R, Denholm I, Dryden MW, Jacobs DE, Mehlhorn H, Mencke N, Payne P, Rust MK, Vaughn MB. Progress of the international work of the "Imidacloprid Flea Susceptibility Monitoring Team". Parasitol Res 2003; 90 Suppl 3:S127-8. [PMID: 12928877 DOI: 10.1007/s00436-003-0913-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- I Schroeder
- Bayer AG, BHC-Business Group Animal Health, D-51368 Leverkusen, Germany
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11
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Spencer JA, Butler JM, Stafford KC, Pough MB, Levy SA, Bledsoe DL, Blagburn BL. Evaluation of permethrin and imidacloprid for prevention of Borrelia burgdorferi transmission from blacklegged ticks (Ixodes scapularis) to Borrelia burgdorferi-free dogs. Parasitol Res 2003; 90 Suppl 3:S106-7. [PMID: 12928869 DOI: 10.1007/s00436-003-0904-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- J A Spencer
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Alabama, USA
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12
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Rust MK, Waggoner M, Hinkle NC, Mencke N, Hansen O, Vaughn M, Dryden MW, Payne P, Blagburn BL, Jacobs DE, Bach T, Bledsoe D, Hopkins T, Mehlhorn H, Denholm I. Development of a larval bioassay for susceptibility of cat fleas (Siphonaptera: Pulicidae) to imidacloprid. J Med Entomol 2002; 39:671-674. [PMID: 12144302 DOI: 10.1603/0022-2585-39.4.671] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Strategies for controlling cat fleas, Ctenocephalidesfelisfelis (Bouché), have undergone dramatic changes in the past 5 yr. With the advent of on-animal treatments with residual activity the potential for the development of insecticide resistance increases. A larval bioassay was developed to determine the baseline susceptibility of field-collected strains of cat fleas to imidacloprid. All four laboratory strains tested showed a similar level of susceptibility to imidacloprid. Advantages of this bioassay are that smaller numbers of fleas are required because flea eggs are collected for the test. Insect growth regulators and other novel insecticides can also be evaluated. Using a discriminating dose, the detection of reduced susceptibility in field strains can be determined with as few as 40 eggs.
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Affiliation(s)
- M K Rust
- Department of Entomology, University of California, Riverside 92521-0314, USA
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13
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Dubey JP, Barr BC, Barta JR, Bjerkås I, Björkman C, Blagburn BL, Bowman DD, Buxton D, Ellis JT, Gottstein B, Hemphill A, Hill DE, Howe DK, Jenkins MC, Kobayashi Y, Koudela B, Marsh AE, Mattsson JG, McAllister MM, Modrý D, Omata Y, Sibley LD, Speer CA, Trees AJ, Uggla A, Upton SJ, Williams DJL, Lindsay DS. Redescription of Neospora caninum and its differentiation from related coccidia. Int J Parasitol 2002; 32:929-46. [PMID: 12076623 DOI: 10.1016/s0020-7519(02)00094-2] [Citation(s) in RCA: 149] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Neospora caninum is a protozoan parasite of animals, which before 1984 was misidentified as Toxoplasma gondii. Infection by this parasite is a major cause of abortion in cattle and causes paralysis in dogs. Since the original description of N. caninum in 1988, considerable progress has been made in the understanding of its life cycle, biology, genetics and diagnosis. In this article, the authors redescribe the parasite, distinguish it from related coccidia, and provide accession numbers to its type specimens deposited in museums.
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Affiliation(s)
- J P Dubey
- Parasite Biology Laboratory, Beltsville Agricultural Research Center, Animal and Natural Resources Institute, United States Department of Agriculture, Building 1001, BARC-East, Beltsville, MD 20705-2350, USA.
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Abstract
Toxoplasma gondii oocysts are excreted nonsporulated in the feces of the cats into the environment. These oocysts must undergo sporulation to become infectious. Little is known about the factors that influence sporulation of T. gondii oocysts. The present study examined the survival of nonsporulated oocysts under refrigerated conditions over 11-week observation period. Microscopic examination of oocysts indicated that no visible development occurred under refrigerator conditions. The nonsporulated oocysts retained their ability to sporulate when placed at room temperature. The numbers of visually viable appearing oocysts decreased over time. Some oocysts in all samples were infectious for mice despite being refrigerated for up to an 11 weeks before undergoing sporulation. Results indicate that nonsporulated oocysts can survive in the environment for at least 3 months and retain their ability to become infectious when placed under appropriate conditions.
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Affiliation(s)
- D S Lindsay
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, 1410 Prices Fork Road, Blacksburg, VA 24061-0442, USA.
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Lindsay DS, Rosypal AC, Spencer JA, Cheadle MA, Zajac AM, Rupprecht C, Dubey JP, Blagburn BL. Prevalence of agglutinating antibodies to Sarcocystis neurona in raccoons, Procyon lotor, from the United States. Vet Parasitol 2001; 100:131-4. [PMID: 11698158 DOI: 10.1016/s0304-4017(01)00494-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Equine protozoal myeloencephalitis (EPM) is the most important protozoal disease of horses in North America and it is caused by Sarcocystis neurona. Natural cases of encephalitis due to S. neurona have been reported in raccoons, Procyon lotor. We examined 99 raccoons for agglutinating antibodies to S. neurona using the S. neurona agglutination test (SAT) employing formalin-fixed merozoites as antigen. Raccoons originated in Florida (N=24, collected in 1996), New Jersey (N=25, collected in 1993), Pennsylvania (N=25, collected in 1999), and Massachusetts (N=25, collected in 1993 and 1994). We found that 58 (58.6%) of the 99 raccoons were positive for antibodies to S. neurona using the SAT; 44 of 99 raccoons (44%) had titers of > or =1:500. This prevalence is similar to the reported seroprevalence of 33-60% for S. neurona antibodies in horses from the United States using the Western blot test.
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Affiliation(s)
- D S Lindsay
- Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, 1410 Prices Fork Road, Blacksburg, VA 24061-0342, USA.
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Abstract
Neospora caninum is an apicomplexan parasite that causes neonatal neuromuscular disease in dogs and abortions in cattle. Dogs are the only proven definitive host. Little is known about the prevalence of antibodies to this parasite in wildlife. Sera from 99 raccoons (Procyon lotor) were examined for agglutinating antibodies to N. caninum using the modified agglutination test employing formalin-fixed tachyzoites as antigen. Raccoons originated in Florida (n = 24, collected in 1996), New Jersey (n = 25, collected in 1993), Pennsylvania (n = 25, collected in 1999), and Massachusetts (n = 25, collected in 1993 and 1994). Ten (10%) had antibodies to N. caninum; 9 had titers of 1:50, and 1 (1%) had a titer of 1:100. The present study indicates that raccoons have minimal exposure to N. caninum. The sera were also tested for agglutinating antibodies to Toxoplasma gondii and 46 (46%) were positive; 16 had titers of 1:50, 8 had titers of 1:100, and 22 had titers of > or = 1:500.
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Affiliation(s)
- D S Lindsay
- Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg 24061-0342, USA.
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17
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Morgan UM, Monis PT, Xiao L, Limor J, Sulaiman I, Raidal S, O'Donoghue P, Gasser R, Murray A, Fayer R, Blagburn BL, Lal AA, Thompson RC. Molecular and phylogenetic characterisation of Cryptosporidium from birds. Int J Parasitol 2001; 31:289-96. [PMID: 11226456 DOI: 10.1016/s0020-7519(00)00164-8] [Citation(s) in RCA: 147] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Avian isolates of Cryptosporidium species from different geographic locations were sequenced at two loci, the 18S rRNA gene and the heat shock gene (HSP-70). Phylogenetic analysis of the sequence data provided support for the existence of a new avian species of Cryptosporidium infecting finches and a second species infecting a black duck. The identity of Cryptosporidium baileyi and Cryptosporidium meleagridis as valid species was confirmed. Also, C. baileyi was identified in a number of isolates from the brown quail extending the host range of this species.
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Affiliation(s)
- U M Morgan
- World Health Organisation Collaborating Centre for the Molecular Epidemiology of Parasitic Infections and State Agricultural Biotechnology Centre, Murdoch University, WA 6150, Australia.
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18
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Macintire DK, Vincent-Johnson NA, Kane CW, Lindsay DS, Blagburn BL, Dillon AR. Treatment of dogs infected with Hepatozoon americanum: 53 cases (1989-1998). J Am Vet Med Assoc 2001; 218:77-82. [PMID: 11149719 DOI: 10.2460/javma.2001.218.77] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine clinical and pathologic findings before and after short-term (group 1) and long-term (group 2) treatment in dogs with Hepatozoon americanum infection. DESIGN Retrospective study. ANIMALS 53 dogs with H. americanum infection. PROCEDURE Medical records of dogs that were treated for hepatozoonosis diagnosed on the basis of meront or merozoite stages in skeletal muscle were reviewed. RESULTS Circulating gametocytes of H. americanum were identified in 12 of 53 dogs. Dogs were treated with various drugs, including toltrazuril, trimethoprim-sulfadiazine, clindamycin, pyrimethamine, and decoquinate. Mean WBC counts prior to treatment were 85,700 and 75,200 cells/microl in groups 1 and 2, respectively, and 1 month after initiation of treatment were 12,600 and 14,600 cells/microl, respectively. Initial response to treatment was excellent in all dogs. Twenty-three of 26 dogs in group 1 relapsed at least once and died within 2 years; mean (+/- SD) survival time was 12.6+/-2.2 months. Twenty-two of 27 group-2 dogs survived; 11 dogs had no clinical signs and were still receiving decoquinate (mean duration of treatment, 21 months), 11 dogs had no clinical signs after treatment for 14 months (range, 3 to 33 months; mean survival time, 39 months [range, 26 to 53 months]), 2 dogs were lost to follow-up, and 3 dogs were euthanatized because of severe disease. CONCLUSIONS AND CLINICAL RELEVANCE Although no treatment effectively eliminated the tissue stages of H. americanum, treatment with trimethoprim-sulfadiazine, clindamycin, and pyrimethamine followed by long-term administration of decoquinate resulted in extended survival times and excellent quality of life.
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Affiliation(s)
- D K Macintire
- Department of Small Animal Surgery and Medicine, College of Veterinary Medicine, Auburn University, AL 36849, USA
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19
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Abstract
Neospora caninum is a recently described coccidial parasite that was first isolated from a dog in 1988 and has subsequently been shown to infect a wide range of mammals. Neospora hughesi, a new species of this genus, has recently been isolated from the spinal cord of horses showing clinical signs of equine protozoal myeloencephalitis. The random amplified polymorphic DNA polymerase chain reaction technique is capable of differentiating between N. caninum and N. hughesi.
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Affiliation(s)
- J A Spencer
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Alabama 36849, USA
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20
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Abstract
Neospora hughesi is a recently described cause of equine protozoal myeloencephalitis (EPM). A rodent model for pathogenicity would facilitate development of therapies to be used in horses. In the present study, we examined the susceptibility of BALB/c gamma-interferon gene knockout (gamma-INFKO), BALB/c, CD-1, and C57BL/6 strains of mice and gerbils to infection with tachyzoites of the Nh-A1 strain of N. hughesi isolated from a horse from AL, USA. Only the gamma-IFNKO mice developed severe clinical disease following infection with N. hughesi and died 19-25 days after infection and exhibited severe cardiac lesions. In contrast, experimental infection of gamma-INFKO mice with tachyzoites of the NC-1 or NC-Liverpool strains of Neospora caninum resulted in deaths 8-10 days after infection. The most severe lesions were in the livers, spleens, and lungs of these mice. Gerbils inoculated with N. hughesi did not develop clinical disease, had few microscopic lesions, but did seroconvert. Two dogs fed the brains of mice, shown to contain N. hughesi tissue stages by cell culture and gamma-IFNKO mouse bioassay, did not shed N. caninum-like oocysts over a 23 days observation period. The marked difference in pathogenicity between the two species of Neospora in gamma-IFNKO mice, and lack of oocyst excretion by dogs fed N. hughesi infected mice provide additional evidence that the species distinction between N. caninum and N. hughesi is valid.
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Affiliation(s)
- C P Walsh
- Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, 24061-0342, USA
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21
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Lindsay DS, Dykstra CC, Williams A, Spencer JA, Lenz SD, Palma K, Dubey JP, Blagburn BL. Inoculation of Sarcocystis neurona merozoites into the central nervous system of horses. Vet Parasitol 2000; 92:157-63. [PMID: 10946139 DOI: 10.1016/s0304-4017(00)00281-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Equine protozoal myeloencephalitis (EPM) is a neurologic syndrome in horses from the Americas and is usually caused by infection with the apicomplexan parasite, Sarcocystis neurona. A horse model of EPM is needed to test the efficacy of chemotherapeutic agents and potential vaccines. Five horses that were negative for antibodies to S. neurona in their serum and cerebrospinal fluid (CSF) were injected in the subarachnoid space with living merozoites of the SN2 isolate of S. neurona. None of the horses developed clinical disease or died over a 132-day observation period. All five horses developed antibodies to S. neurona in their CSF and serum 3-4 weeks after injection. Two of the horses were examined at necropsy and no parasite induced lesions were observed in their tissues and no parasites were recovered from portions of their spinal cords inoculated on to cell cultures. Results of this study demonstrate that merozoites of the SN2 isolate of S. neurona will induce seroconversion but not clinical disease when inoculated directly into the CSF of nonimmune horses.
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Affiliation(s)
- D S Lindsay
- Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, 24061-0342, USA.
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22
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McTier TL, Shanks DJ, Jernigan AD, Rowan TG, Jones RL, Murphy MG, Wang C, Smith DG, Holbert MS, Blagburn BL. Evaluation of the effects of selamectin against adult and immature stages of fleas (Ctenocephalides felis felis) on dogs and cats. Vet Parasitol 2000; 91:201-12. [PMID: 10940522 DOI: 10.1016/s0304-4017(00)00292-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The adulticidal, ovicidal, and larvicidal effects of selamectin against flea (Ctenocephalides felis felis) infestations on dogs and cats were evaluated in a series of seven controlled and masked studies (three in cats, four in dogs). Animals were randomly allocated to treatment with either selamectin at a minimum dosage of 6mgkg(-1) in the commercial formulation or one of two negative-controls (0.9% NaCl solution or the vehicle from the commercial formulation). Treatments were administered topically in a single spot on the skin at the base of the neck in front of the scapulae. Speed of kill, measured by flea comb counts at 12h intervals during the 48h immediately following a single treatment on day 0, was evaluated in two studies. One study was in dogs and the other in cats, and each animal was infested with approximately 100 unfed viable adult fleas prior to treatment. Reductions in geometric mean flea counts for selamectin compared with saline were >98% between 24 and 36h after treatment in dogs, and between 12 and 24h after treatment in cats (P< or =0.0006). Efficacy in reducing flea egg hatch and larval development was evaluated in four studies, in which dogs and cats were treated once on day 0 and then repeatedly infested with approximately 600 fleas. Flea eggs were collected approximately for 72h after each infestation, on days 3, 7, 14, 21, and 30, counted, and cultured to determine their hatchability and subsequent larval development. Compared with the vehicle, selamectin was highly effective in reducing flea egg hatch (>92% in cats) and larval development (> or =95% for dogs and cats), and emergence of adults (97.8-100% for dogs, 85.6-100% for cats) for 30 days. Effects of exposure to hair coat debris were investigated in a study with dogs treated once on day 0 and repeatedly infested with 100 adult fleas. Debris (dander, flea faeces, hair, scales) was collected on days 1, 7, 14, 21, and 30 and added to normal flea eggs or larvae for incubation. Compared with debris from vehicle-treated dogs, debris from selamectin-treated dogs was highly effective in preventing egg hatch (>96%), in killing larvae (>98%) and in preventing larval development to adults (>99%) (P</=0.0033). Selamectin was shown to be highly effective in the treatment and control of flea infestations (C. felis) on dogs and cats. The adulticidal, ovicidal, and larvicidal effects of selamectin will be important in interrupting the flea life cycle by preventing the introduction and establishment of new flea infestations in a household environment.
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Affiliation(s)
- T L McTier
- Animal Health Clinical Affairs, Central Research Division, Pfizer Inc., Groton, CT 06340, USA.
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23
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Abstract
Cryptosporidium parvum is an apicomplexan parasite that is an important cause of diarrhea in neonatal calves and humans. No treatment is currently available for neonatal calves. We have recently learned from colleagues in the pharmaceutical industry that dairy practitioners are sometimes using decoquinate for the treatment of neonatal bovine cryptosporidiosis. Therefore, the present study was undertaken to determine whether the clinical observations in calves can be substantiated by laboratory investigation. Oocysts of the KSU-1 isolate of C. parvum were used to infect human ileocecal epithelial cells in vitro to measure the efficacy of treatment using an ELISA based assay. No activity was observed at 10 or 50microM decoquinate, but at 100microM an 8% inhibition of development was seen. Oocysts of the AUCp-1 isolate of C. parvum were then used to infect suckling mice. The numbers of oocysts observed in suckling mice treated with 2.5 or 5.0mg/kg decoquinate were not significantly different from untreated control suckling mice (p0.05). The results of our study suggest that decoquinate should have little efficacy for treatment of neonatal bovine cryptosporidiosis if administered once per day and that any clinical improvement observed in treated calves may be due to factors unrelated to decoquinate's effect on C. parvum.
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Affiliation(s)
- D S Lindsay
- Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24061-0342, USA.
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24
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Trampel DW, Pepper TM, Blagburn BL. Urinary tract cryptosporidiosis in commercial laying hens. Avian Dis 2000; 44:479-84. [PMID: 10879932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Formalin-fixed kidney tissues from adult egg-laying chickens in two houses of an egg-production complex in the upper Midwest were submitted to Iowa State University for histopathologic examination. An increased incidence of visceral gout, average daily mortality 1%-2% higher than expected, and egg production within normal limits were observed in both houses. Numerous developing stages of Cryptosporidium were observed on the apical surface of epithelial cells lining renal collecting tubules and ureters. Scanning and transmission electron microscopy were used to visualize colonization of cryptosporidia, disruption of microvilli, and exfoliation of parasitized epithelial cells. Lymphoplasmacytic infiltration in the wall of ureters and hyperplasia of parasitized epithelial cells resulted in partial obstruction of ureters, which may have induced visceral gout in affected hens. This is the first report of urinary tract cryptosporidiosis occurring in adult hens in a modern commercial egg-production facility.
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Affiliation(s)
- D W Trampel
- Department of Veterinary Diagnostics and Production Animal Medicine, Iowa State University, Ames 50011, USA
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25
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Lindsay DS, Upton SJ, Owens DS, Morgan UM, Mead JR, Blagburn BL. Cryptosporidium andersoni n. sp. (Apicomplexa: Cryptosporiidae) from cattle, Bos taurus. J Eukaryot Microbiol 2000; 47:91-5. [PMID: 10651302 DOI: 10.1111/j.1550-7408.2000.tb00016.x] [Citation(s) in RCA: 174] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A new species of Cryptosporidium is described from the feces of domestic cattle, Bos taurus. Oocysts are structurally similar to those of Cryptosporidium muris described from mice but are larger than those of Cryptosporidium parvum. Oocysts of the new species are ellipsoidal, lack sporocysts, and measure 7.4 x 5.5 microm (range, 6.0-8.1 by 5.0-6.5 microm). The length to width ratio is 1.35 (range, 1.07-1.50). The colorless oocyst wall is < 1 microm thick, lacks a micropyle, and possesses a longitudinal suture at one pole. A polar granule is absent, whereas an oocyst residuum is present. Oocysts were passed fully sporulated and are not infectious to outbred, inbred immunocompetent or immunodeficient mice, chickens or goats. Recent molecular analyses of the rDNA 18S and ITS1 regions and heat-shock protein 70 (HSP-70) genes demonstrate this species to be distinct from C. muris infecting rodents. Based on transmission studies and molecular data, we consider the large form of Cryptosporidium infecting the abomasum of cattle to be a new species and have proposed the name Cryptosporidium andersoni n. sp. for this parasite.
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Affiliation(s)
- D S Lindsay
- Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg 24061-0342, USA.
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26
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Blagburn BL, Vaughan JL, Butler JM, Parks SC. Dose titration of an injectable formulation of lufenuron in cats experimentally infested with fleas. Am J Vet Res 1999; 60:1513-5. [PMID: 10622160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
OBJECTIVES To identify the lowest single dose of lufenuron injected s.c. that results in a 90% disruption of the flea (Ctenocephalides felis) life cycle for 6 months in cats. ANIMALS 40 domestic shorthair cats (20 males, 20 females) between 5 and 7 months old. PROCEDURE Cats were randomly assigned to 1 of 5 eight-cat groups and experimentally infested with C. felis on days -8, -7, -6, and -4. On day 0, cats in the 4 treatment groups were treated with an injectable formulation of lufenuron at doses of 2.5, 5, 10, or 20 mg/kg of body weight, respectively. Control cats received the injectable formulation without lufenuron. Experimental infestations were repeated and flea eggs collected at various intervals for 196 days after treatment. Eggs were placed in media and incubated in an insectary for 28 days to determine effects of injectable lufenuron on egg and larval development. Number of adults that emerged from eggs were compared among groups. RESULTS Lufenuron injected once at a dose of 10 or 20 mg/kg, but not at 2.5 or 5 mg/kg, resulted in a 90% decrease in number of adult fleas emerging from eggs for 196 days after treatment. CONCLUSIONS AND CLINICAL RELEVANCE Results indicate that control of flea egg and larval development for at least 6 months can be achieved in cats with a single s.c. injection of lufenuron (10 mg/kg). The injectable formulation may provide veterinarians and cat owners an alternative to the tablet formulation of lufenuron.
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Affiliation(s)
- B L Blagburn
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, AL 36849, USA
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27
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Cheadle MA, Lindsay DS, Rowe S, Dykstra CC, Williams MA, Spencer JA, Toivio-Kinnucan MA, Lenz SD, Newton JC, Rolsma MD, Blagburn BL. Prevalence of antibodies to Neospora sp. in horses from Alabama and characterisation of an isolate recovered from a naturally infected horse [corrected]. Int J Parasitol 1999; 29:1537-43. [PMID: 10608440 DOI: 10.1016/s0020-7519(99)00140-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
An IFAT was used to determine the prevalence of Neospora-specific IgG antibodies in serum from Alabama horses. Serum samples (n = 536) were from asymptomatic horses routinely submitted for equine infectious anaemia virus infection testing. We also subjected a 13-year-old horse with CNS disease to necropsy examination for isolation and in vitro cultivation of protozoal organisms. In antemortem tests, this horse was positive for antibodies to Neospora sp. in the IFAT and western immunoblot. Results of the prevalence survey indicated that IgG antibodies to Neospora were present in 62 (11.5%) of the 536 serum samples. Endpoint titres for the positive samples were 1:50 (35/6.5%), 1:100 (19/3.5%), 1:200 (7/1.3%) and 1:1600 (1/0.2%). Tachyzoites were first seen in cultured bovine turbinate cells 32 days after inoculation with spinal cord homogenates from the horse with CNS disease. Tachyzoites reacted with known N. caninum-positive serum from horses, cows, dogs and mice, but did not react with murine anti-Toxoplasma gondii or equine anti-Sarcocystis neurona serum. Ultrastructural features of tachyzoites and results of comparison of tachyzoite immunodominant proteins revealed that they were identical to those of N. hughesi, a species described recently from a naturally infected horse. The isolate recovered from the naturally infected horse in the present study (designated NA1) is thought to be an isolate of N. hughesi, although confirmation of this awaits additional molecular characterisation. These results provide some additional evidence that N. hughesi is a valid species and that Neospora infections in horses may occur in widely separated geographic regions of the United States.
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Affiliation(s)
- M A Cheadle
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, AL 36849, USA
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28
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Abstract
Serum samples from 1077 dogs suspected of having Neospora caninum infections from 35 states in the United States and 3 provinces in Canada were tested for N. caninum IgG antibodies by the indirect fluorescent antibody test. Antibodies to N. caninum were found in 75 of 1077 (7%) of the samples. Twenty of the positive dogs were females, 17 were males and the sex was not recorded on 38 dogs. Chi square analysis indicated no differences (P > 0.05) based on sex were present. Dogs from the Southeast and Midwest regions of the United States were more likely to be N. caninum antibody positive than were dogs from the Northeast or West regions.
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Affiliation(s)
- M A Cheadle
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Alabama 36849, USA
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29
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Cheadle MA, Toivio-Kinnucan M, Blagburn BL. The ultrastructure of gametogenesis of cryptosporidium baileyi (eimeriorina; cryptosporidiidae) in the respiratory tract of broiler chickens (Gallus domesticus). J Parasitol 1999; 85:609-15. [PMID: 10461939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023] Open
Abstract
The ultrastructural features of sexual development of Cryptosporidium baileyi in the respiratory tract of experimentally infected broiler chickens were studied using transmission electron microscopy. Sexual stages of C. baileyi were seen attached to the tracheal epithelium and free in the tracheal lumen. These stages included intracellular type III merozoite-like stages, microgamonts, microgametes, macrogamonts, thin-walled oocysts, and thick-walled oocysts. These stages were developmentally similar to those observed for other Cryptosporidium species. All of the above stages were observed during each study day. Thin-walled oocysts, microgamonts, and microgametes were seen less frequently than other sexual stages. Microgamonts, macrogamonts, and oocysts attached to the epithelium were all contained in a host cell membrane or within a parasitophorous vacuole. Thin-walled oocysts of C. baileyi were observed for the first time on an ultrastructural level in the respiratory tract of chickens.
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Affiliation(s)
- M A Cheadle
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Alabama 36849-5519, USA
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30
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Cheadle MA, Spencer JA, Blagburn BL. Seroprevalences of Neospora caninum and Toxoplasma gondii in nondomestic felids from southern Africa. J Zoo Wildl Med 1999; 30:248-51. [PMID: 10484140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023] Open
Abstract
Sera from 68 nondomestic captive and free-ranging felids from southern Africa were tested for antibodies to Neospora caninum and Toxoplasma gondii by the indirect fluorescent antibody test. Four of the 68 (5.9%) serum samples were positive for antibodies to N. caninum, with titers ranging from 1:50 to 1:200. All other animals were negative for antibodies to N. caninum at a dilution of 1:50. Fifty of the 68 (74%) serum samples tested positive for antibodies to T. gondii, with titers ranging from 1:50 to 1:26,500. Four animals tested positive for antibodies to both N. caninum and T. gondii. None of these animals displayed clinical signs of disease. Results of this study indicate that nondomestic felids in southern Africa have been exposed to, and are likely infected with, N. caninum and T. gondii.
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Affiliation(s)
- M A Cheadle
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Alabama 36849, USA
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31
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Lindsay DS, Lenz SD, Blagburn BL, Brake DA. Characterization of temperature-sensitive strains of Neospora caninum in mice. J Parasitol 1999; 85:64-7. [PMID: 10207365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023] Open
Abstract
Temperature-sensitive (ts) strains of the Neospora caninum tachyzoites were selected by chemical mutagenesis and selection for growth at 32 C. Three ts strains and the parental, N. caninum wild-type strain, NC-1, were examined in the present study for their ability to cause disease in inbred BALB/c mice, outbred ICR mice, and chemically immunosuppressed ICR mice. In BALB/c mice, all 3 strains failed to induce clinical disease, whereas infection with the NC-1 strain caused central nervous system disease and death in some mice. No disease was observed in ICR mice inoculated with the 3 ts strains or the NC-1 strain. All immunosuppressed ICR mice inoculated with the NC-1 strain died, whereas no immunosuppressed mice inoculated with the NCts-4 strain and only 1 of 5 mice inoculated with the NCts-8 and NCts-12 strains died. The NCts-4 and NCts-12 strains reverted to a wild-type phenotype when grown at 37 C. Vaccination of BALB/c mice with live, but not frozen NCts-8 strain tachyzoites induced significant (P < 0.05) protection following NC-1 strain challenge.
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Affiliation(s)
- D S Lindsay
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg 24061-0442, USA
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32
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Abstract
An acid-pepsin digestion technique was used to examine portions of breast muscle and heart from raptors for encysted protozoans. Apicomplexan zoites were present in 52 (45.6%) of the 114 samples examined: 11 of 12 (91.7%) red-shouldered hawks (Buteo lineatus), 20 of 34 (58.8%) red-tailed hawks (Buteo jamaicensis), two of seven (28.6%) Cooper's hawks (Accipiter cooperi), three of four (75%) sharp-shinned hawks (Accipiter striatus), one (100%) Mississippi kites (Ictinia misisippiensis), one of two (50%) American kestrels (Falco sparverius), one bald eagle (Haliaeetus leucocephalus), one of two (50%) golden eagles (Aquila chrysaetos), one of three (33%) turkey vultures (Cathartes aura), two of three (66.7%) black vultures (Coragyps atratus), three of six (50%) great-horned owls (Bubo virginianus), five of 15 (33.3%) barred owls (Strix varia), and one of 12 (8.3%) screech owls (Asio otus). Encysted protozoans were not observed in digests of tissues from three broad-winged hawks (Buteo platypterus), four ospreys (Pandion haliaetus), and five barn owls (Tyto alba). Apicomplexan cysts resembling Sarcocystis species were observed in tissue sections of muscles from 28 (37.8%) of 74 raptors.
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Affiliation(s)
- D S Lindsay
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg 24061-0342, USA.
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33
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Blagburn BL, Drain KL, Land TM, Kinard RG, Moore PH, Lindsay DS, Patrick DA, Boykin DW, Tidwell RR. Comparative efficacy evaluation of dicationic carbazole compounds, nitazoxanide, and paromomycin against Cryptosporidium parvum infections in a neonatal mouse model. Antimicrob Agents Chemother 1998; 42:2877-82. [PMID: 9797219 PMCID: PMC105959 DOI: 10.1128/aac.42.11.2877] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The efficacies of dicationic carbazole compounds, nitazoxanide (NTZ), and paromomycin were evaluated against the AUCp1 isolate of Cryptosporidium parvum by using a neonatal mouse model. Compounds were solubilized or suspended in deionized water and administered orally by gavage to neonatal mice at a constant dose rate on days 0 to 5 (treatment started on day 0). Dose rates varied for individual carbazole compounds but ranged from 0.65 to 20 mg/kg of body weight. NTZ was tested at 100 and 150 mg/kg, and paromomycin was tested at 50 mg/kg. Efficacies were determined by comparing numbers of oocysts present in treated versus control mice at necropsy examination on day 6. Demonstrable efficacy was observed for several carbazole compounds, based on significant reductions in the numbers of oocysts recovered from treated mice versus control mice. Compounds 1, 7, and 10 (19.0 mg/kg) reduced oocyst passage in treated mice to less than 5% of that in control mice. Treatment with compounds 6, 8, and 9 (17.0 mg/kg) resulted in reductions of oocyst output to less than 10% of that in controls. Although they were not comparable in efficacy to compounds 1, 6, 7, 8, 9, and 10, treatment with other carbazole compounds resulted in statistically significant reductions in oocyst output in treated versus control mice. Compound 1 retained efficacy resulted in reduction of oocyst output to approximately 6% of that in controls when the dose was reduced to 5 mg/kg. Further reductions in the dose rate resulted in considerable reductions in anticryposporidial activity. Likewise, the efficacies of compounds 9 and 10 were reduced substantially when the doses were lowered to one-half the screening dose. Paromomycin yielded excellent activity (reduction of oocyst output to <2% of that in controls) at a dose of 50 mg/kg. NTZ yielded moderate efficacy as powder and injectable formulations administered at 100 mg/kg orally (reduction of oocyst output to 42 and 26% of that in controls, respectively). Oral administration of the injectable formulation of NTZ at a dose of 150 mg/kg resulted in improved efficacy (oocyst output, <5% of that in controls).
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Affiliation(s)
- B L Blagburn
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, Alabama 36849-5519, USA.
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Blagburn BL, Drain KL, Land TM, Moore PH, Kinard RG, Lindsay DS, Kumar A, Shi J, Boykin DW, Tidwell RR. Dicationic furans inhibit development of Cryptosporidium parvum in HSD/ICR suckling Swiss mice. J Parasitol 1998; 84:851-6. [PMID: 9714224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The efficacy of dicationic diarylfurans was evaluated against Cryptosporidium parvum by a suckling murine model. Candidate drugs were solubilized or suspended in deionized water and administered orally at a constant dose rate on days 0-5 (treatment day 0) to suckling ICR Swiss mice experimentally inoculated with oocysts of C. parvum. Efficacy was based on numbers of oocysts recovered from the intestinal tracts of mice subjected to necropsy examination on day 6. Numerous candidate furans significantly reduced the numbers of oocysts recovered from treated mice compared with control mice. Compounds 1, 2, 4, and 9 demonstrated superior efficacies (10% of controls or better) against C. parvum. Compounds 3, 5, 6, 7, 8, 11, 17, 18, and 19 also significantly reduced the numbers of oocysts recovered from treated mice but demonstrated efficacies ranging from 17 to 65% of controls. Compound 4 was particularly efficacious against C. parvum at a dosage as low as 8.5 mg/kg of body weight. Compound 4 is identified as a lead compound for additional studies in other animal models.
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Affiliation(s)
- B L Blagburn
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Alabama 36849-5519, USA
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Abstract
Decoquinate is an anticoccidial agent that inhibits respiration in the parasites mitochondrion. We examined human foreskin fibroblast cell cultures infected with the normally tissue cyst-less RH strain of Toxoplasma gondii and treated with decoquinate for evidence of tissue cyst induction and formation. Transmission electron microscopy observations demonstrated tissue cysts in decoquinate-treated cultures on days 3, 4, 5, and 6 after inoculation. Tissue cysts contained a tissue cyst wall that enclosed stages that resembled tachyzoites and stages that were structurally bradyzoites. Similar treatment of human foreskin fibroblast cells infected with tachyzoites of the TS-4 temperature-sensitive mutant of the RH strain did not result in production of tissue cysts.
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Affiliation(s)
- D S Lindsay
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, AL 36849-5519, USA
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Lindsay DS, Quick DP, Steger AM, Toivio-Kinnucan MA, Blagburn BL. Complete development of the porcine coccidium Isospora suis Biester, 1934 in cell cultures. J Parasitol 1998; 84:635-7. [PMID: 9645875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Development from inoculated sporozoites to unsporulated oocysts of Isospora suis Biester, 1934 is described in a swine testicular (ST) cell line. Sporozoites penetrated ST cells within 1 hr postinoculation (PI). Development was initially by endodyogeny to produce binucleate type I meronts and type I merozoites. Division by endodyogeny continued during the 13-day observation period and type I merozoites were the developmental stages most abundant at observation periods >3 days PI. Mutinucleate type II meronts and type II merozoites were first observed 7 days PI. Gamonts and oocysts were present 12 days PI. Oocysts did not sporulate in vitro. The ultrastructural features of stages were similar to those that occur in the pig host.
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Affiliation(s)
- D S Lindsay
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg 24061-0342, USA
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Lindsay DS, Lenz SD, Dykstra CC, Blagburn BL, Dubey JP. Vaccination of mice with Neospora caninum: response to oral challenge with Toxoplasma gondii oocysts. J Parasitol 1998; 84:311-5. [PMID: 9576504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Neospora caninum is a protozoan parasite that can cause severe disease in mammals. Two experiments were conducted to examine the effects of subcutaneous (s.c.) vaccination with Hank's balanced salt solution (HBSS), 1 x 10(5) N. caninum NC-1 strain tachyzoites or 1 x 10(5) Toxoplasma gondii TS-4 strain tachyzoites on challenge oral infections in mice with sporulated VEG strain T. gondii oocysts (1 X 10(3) oocysts exp. 1 and 5 x 10(3) oocysts exp. 2). An additional study, experiment 3, evaluated s.c. challenge with 2.5 X 10(3) tachyzoites of the highly virulent RH strain of T. gondii after vaccination with HBSS, NC-1 tachyzoites, or TS-4 tachyzoites. Mice vaccinated with NC-1 strain tachyzoites survived significantly (P < 0.05) longer than mice given HBSS in experiment 1, but not in experiments 2 and 3. Mice vaccinated with TS-4 strain tachyzoites survived significantly longer than HBSS-vaccinated mice in experiments 1, 2, and 3 and significantly longer than mice vaccinated with the NC-1 strain in experiments 2 and 3. Toxoplasma gondii tissue cyst numbers were significantly lower for mice vaccinated with TS-4 strain tachyzoites than mice vaccinated with HBSS or the NC-1 strain tachyzoites in experiment 1. No difference was observed in tissue cyst numbers in mice vaccinated with HBSS or NC-1 strain tachyzoites in experiment 1. No HBSS-vaccinated mice survived experiment 2, and the numbers of T. gondii tissue cysts were significantly lower for mice vaccinated with the TS-4 strain tachyzoites compared to NC-1 strain tachyzoites. No HBSS- or NC-1-vaccinated mice survived RH strain challenge in experiment 3. Results of these experiments indicate that infection with N. caninum provides some protection against fatal oral infection with T gondii oocysts of a moderately pathogenic strain but not tachyzoites of a highly pathogenic strain. The protection provided by N. caninum is much less than that provided by previous exposure to T. gondii, and the numbers of tissue cysts in the brains of mice are not significantly (P > 00.5) lowered.
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Affiliation(s)
- D S Lindsay
- Department of Pathology, College of Veterinary Medicine, Auburn University, Alabama 36849-5519, USA
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Abstract
Two experiments were conducted to determine if dogs could mechanically transmit Toxoplasma gondii after ingesting cat feces or by rolling in cat feces containing oocysts. In the first experiment, two dogs were fed sporulated T. gondii oocysts; viable sporulated oocysts were present in dog feces for up to 2 days postinoculation (PI). Both dogs seroconverted to T. gondii but did not develop clinical signs of toxoplasmosis. In the second experiment, nonsporulated oocysts were placed on dog skin and fur, and fur clippings were bioassayed for T. gondii in mice. Oocysts did not sporulate on dog fur. The results of this study support the hypothesis that dogs may be involved in the mechanical transmission of T. gondii to humans.
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Affiliation(s)
- D S Lindsay
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, AL 36849-5519, USA
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Vincent-Johnson NA, Macintire DK, Lindsay DS, Lenz SD, Baneth G, Shkap V, Blagburn BL. A new Hepatozoon species from dogs: description of the causative agent of canine hepatozoonosis in North America. J Parasitol 1997; 83:1165-72. [PMID: 9406796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
A new species of Adeleina, Hepatozoon americanum, is described from the skeletal muscle, cardiac muscle, visceral organs, and blood of dogs (Canis familiaris) in the Southern United States. The organism was previously identified as Hepatozoon canis (James, 1905) Wenyon, 1926; however, differences in clinical signs, histopathological and serological findings, gamont size, and ultrastructure define the new species of Hepatozoon. Attempts to transmit the protozoan from infected dogs to nymphal Rhipicephalus sanguineus ticks, the definitive host of H. canis, were not successful.
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Affiliation(s)
- N A Vincent-Johnson
- Department of Small Animal Surgery and Medicine, College of Veterinary Medicine, Auburn University, Alabama 36849-5523, USA
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Heath HL, Blagburn BL, Elsasser TH, Pugh DG, Sanders LG, Sartin EA, Steele B, Sartin JL. Hormonal modulation of the physiologic responses of calves infected with Eimeria bovis. Am J Vet Res 1997; 58:891-6. [PMID: 9256977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE To determine whether an estradiol-progesterone (EP) growth implant would have an effect on febrile responses and on the catabolic component of Eimeria bovis infection. ANIMALS 27 Holstein bull calves. PROCEDURE Calves were assigned to treatment groups as: control (n = 5), EP implant (EP, n = 5), E bovis-inoculated (coccidia: C, n = 7), pair fed (n = 4), or EP plus E bovis-inoculated coccidia (EP/C, n = 6) groups. Calves were provided subcutaneous EP implants at 8 weeks of age, and were inoculated with 2 x 10(5) oocysts of E bovis at 11 weeks of age. Body weight was measured on postinoculation day (PID) 0, 14, and 28. Rectal temperature and food intake were determined and fecal samples were collected daily from PID 15 to 28. Blood samples were collected on PID 24 for analysis of CD2+, CD4+, and CD8+ antigens and plasma insulin-like growth factor I concentration. Blood samples were collected at 15-minute intervals for measurement of pulsatile growth hormone release. RESULTS Group-EP/C calves had fever for 2 days versus 5 days for group-C calves (P < 0.05). These calves had diarrhea for fewer days than did their group-C counterparts (P < 0.05). Fibrinogen and glucose values were high in group-C (P < 0.05) but not group-EP/C calves. The latter had positive weight gain from PID 14 to 28, whereas group-C calves had weight loss (P < 0.05). Plasma insulin-like growth factor I concentration was reduced by infection (P < 0.05). EP-treated noninfected calves had increased numbers of CD2+, CD4+, and CD8+ blood mononuclear cells (P < 0.05). CONCLUSIONS EP has a protective effect in calves infected with E bovis. This may relate to changes in immune function induced by EP. CLINICAL RELEVANCE Treatment of calves with EP could offer some protection against the often severe wasting and debilitation associated with E bovis infection.
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Affiliation(s)
- H L Heath
- Department of Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, AL 36849, USA
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Lindsay DS, Dubey JP, Toivio-Kinnucan MA, Michiels JF, Blagburn BL. Examination of extraintestinal tissue cysts of Isospora belli. J Parasitol 1997; 83:620-5. [PMID: 9267401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Relapse is common in immunocompetent and immunosuppressed humans infected with Isospora belli and is believed to be associated with the presence of extraintestinal stages. In the present study, we examined this important stage in an AIDS patient using histological, immunohistological, histochemical, and ultrastructural methods to better understand the development and structure of this stage and to develop better means of detecting infections. Antisera made in rabbits to Isospora suis, Toxoplasma gondii, Hammondia hammondi, Sarcocystis neurona, Neospora caninum, and Caryospora bigenetica were tested against I. belli tissue cysts in the avidin-biotin peroxidase complex (ABC) immunohistological test. Most antisera reacted positively in the ABC test at dilutions of 1:100 but not at dilutions of 1:250. Some antisera to N. caninum and H. hammondi reacted positively at dilutions of 1:1,000 in the ABC test. Most reactive antisera stained the tissue cyst wall and not the enclosed zoite. Eight histochemical tests were examined and most were nonreactive with I. belli zoites or tissue cysts. Transmission electron microscopy revealed that the tissue cyst wall was composed of granular material and was directly beneath the parasitophorous vacuole membrane. Zoites were in the center of the tissue cysts and were surrounded by fibrillar material that appeared to originate from the zoite surface. Tubulelike structures were present in the granular tissue cyst wall and in the fibrillar material that surrounded the zoite. Zoites contained a crystalloid body. New findings in the present study consisted of identifying what are probably early tissue cysts that lack a developed tissue cyst wall, demonstrating that more than 1 tissue cyst can occupy a host cell, describing the distribution of micronemes and the shedding of zoite membranes, and identifying tubular structures in the inner tissue cyst wall and inner compartment.
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Affiliation(s)
- D S Lindsay
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Alabama 36849-6519, USA
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Abstract
Coccidial parasites of the genus Isospora cause intestinal disease in several mammalian host species. These protozoal parasites have asexual and sexual stages within intestinal cells of their hosts and produce an environmentally resistant cyst stage, the oocyst. Infections are acquired by the ingestion of infective (sporulated) oocysts in contaminated food or water. Some species of mammalian Isospora have evolved the ability to use paratenic (transport) hosts. In these cases, infections can be acquired by ingestion of an infected paratenic host. Human intestinal isosporiasis is caused by Isospora belli. Symptoms of I. belli infection in immunocompetent patients include diarrhea, steatorrhea, headache, fever, malaise, abdominal pain, vomiting, dehydration, and weight loss, blood is not usually present in the feces. The disease is often chronic, with parasites present in the feces or biopsy specimens for several months to years. Recurrences are common, Symptoms are more severe in AIDS patients, with the diarrhea being more watery. Extraintestinal stages of I. belli have been observed in AIDS patients but not immunocompetent patients. Treatment of I. belli infection with trimethoprim-sulfamethoxazole usually results in a rapid clinical response. Maintenance treatment with trimethoprim-sulfamethoxazole is needed because relapses often occur once treatment is stopped.
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Affiliation(s)
- D S Lindsay
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Alabama 36849-5519, USA.
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Abstract
Neospora caninum is a major cause of abortion in dairy cattle in the United States and other countries. Abortions and neonatal mortality also occur in other ruminant species. Decoquinate is an anticoccidial that is approved for use in cattle and goats in the United States. We studied the efficacy of decoquinate against tachyzoites of N. caninum in a 5-day of treatment, cell culture flask lesion-based assay. Decoquinate killed tachyzoites at concentrations of 0.1 and 0.01 microgram ml-1. Decoquinate had little measurable effect on extracellular tachyzoites. Decoquinate acted quickly to kill intracellular stages at coccidiocidal concentrations; tachyzoites were killed within 5 min at 0.1 microgram ml-1 decoquinate.
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Affiliation(s)
- D S Lindsay
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, AL 36849-5519, USA
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Trent JO, Clark GR, Kumar A, Wilson WD, Boykin DW, Hall JE, Tidwell RR, Blagburn BL, Neidle S. Targeting the minor groove of DNA: crystal structures of two complexes between furan derivatives of berenil and the DNA dodecamer d(CGCGAATTCGCG)2. J Med Chem 1996; 39:4554-62. [PMID: 8917643 DOI: 10.1021/jm9604484] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Crystal structures are reported of complexes of two novel furan derivatives of berenil with alkyl benzamidine groups bound to the DNA sequence d(CGCGAATTCGCG)2. They have both been determined to 2.2 A resolution and refined to R factors of 16.9% and 18.6%. In both structures the alkyl substituents, cyclopropyl and isopropyl, are found to be orientated away from the floor of the minor groove. The drugs are located in the minor groove by two strong amidinium hydrogen bonds, to the O2 of the thymines situated at the 5' and 3' ends of the AT-rich region. The isopropyl-substituted derivative has a tight hydrogen-bonded water network in the minor groove at one amidine site, which alters the orientation of the isopropyl substituent. This compound has superior DNA-binding properties and activity against Pneumocystis carinii and Cryptosporidium parvum infections in vivo compared to the cyclopropyl derivative, which in turn is superior to the parent furan compound. We suggest that the nature and extent of the interactions of these compounds in the DNA minor groove play an important role in these activities, possibly in conjunction with a DNA-binding protein. The overall effect of these alkyl benzamidine substitutions is to increase the binding of the drugs to the minor groove.
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Affiliation(s)
- J O Trent
- CRC Biomolecular Structure Unit, Institute of Cancer Research, Sutton, Surrey, UK
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Affiliation(s)
- D S Lindsay
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, AL 36849-5519, USA
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Abstract
Tissue cyst induced Toxoplasma gondii infections were examined in 2 beagle dogs orally inoculated with tissue cysts. Neither dog developed clinical signs of toxoplasmosis. Both dogs developed low antibody titers to T. gondii. The MAT and IFAT were superior to the LAT and IHT tests for detecting antibodies to T. gondii.
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Affiliation(s)
- D S Lindsay
- Dept. of Pathobiol., Col. Vet. Med., Auburn Univ., AL 36849-5519, USA
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Lindsay DS, Kelly EJ, McKown RD, Stein FJ, Plozer J, Herman J, Blagburn BL, Dubey JP. Prevalence of Neospora caninum and Toxoplasma gondii antibodies in coyotes (Canis latrans) and experimental infections of coyotes with Neospora caninum. J Parasitol 1996; 82:657-9. [PMID: 8691381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Antibodies to Neospora caninum were detected in 5 (10%) of 52 coyotes from Texas. Antibodies to Toxoplasma gondii were detected in 32 (62%) of 52 samples from these same coyotes. Four (80%) of the 5 coyotes that were seropositive for N. caninum also had antibodies to T. gondii. Nineteen (37%) of the coyotes did not have antibodies to either parasite. Three coyote pups were inoculated with the brains from mice infected with 3 strains of N. caninum originally isolated from dogs. None of the pups developed neosporosis or excreted N. caninum oocysts in their feces. The pups developed anti-N. caninum antibody titers of > or = 1:800 but did not develop antibodies to T. gondii. Results of this study indicate that antibodies to T. gondii are more common than antibodies to N. caninum in coyotes. Additionally, young coyotes appear to be resistant to experimental N. caninum infection.
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Affiliation(s)
- D S Lindsay
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Alabama 36849-5519, USA
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Lindsay DS, McKown R, Upton SJ, McAllister CT, Toivio-Kinnucan MA, Veatch JK, Blagburn BL. Prevalence and identity of Sarcocystis infections in armadillos (Dasypus novemcinctus). J Parasitol 1996; 82:518-20. [PMID: 8636867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Little is known about the prevalence or identity of Sarcocystis species infecting armadillos in North America. Sarcocysts were observed in the tongues of 23 (96%) of 24 armadillos collected between 1989 and 1994 from Texas, Oklahoma, Kansas, and Arkansas. The identity of the species present was determined in histological sections of tongue from armadillos. Sarcocystis dasypi was present in 21 (88%) and Sarcocystis diminuta was present in 5 (21%). Mixed infections with S. dasypi and S. diminuta were present in 3 (13%) armadillos. A single sarcocyst with ultrastructural features distinct from S. dasypi and S. diminuta was observed with transmission electron microscopy.
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Affiliation(s)
- D S Lindsay
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Alabama 36849-5519, USA
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Dubey JP, Lindsay DS, Adams DS, Gay JM, Baszler TV, Blagburn BL, Thulliez P. Serologic responses of cattle and other animals infected with Neospora caninum. Am J Vet Res 1996; 57:329-36. [PMID: 8669764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE To examine cross-reactivity among Neospora caninum and closely-related apicomplexans. DESIGN Sera from animals were examined for antibody production to N caninum and cross-reactivity to Toxoplasma gondii. ANIMALS Cattle were experimentally infected with 3 tissue cyst-forming protozoan parasites N caninum, T gondii, and Sarcocystis sp, and calves were monospecifically inoculated with the intestinal coccidia, Eimeria bovis and Cryptosporidium parvum. Similar studies were done in laboratory rabbits inoculated with N caninum, T gondii, Hammondia hammondi, and Sarcocystis sp. Additionally, sera were obtained from ewes, lambs, goats, sows, cats, rats, and mice inoculated with N caninum tachyzoites. PROCEDURE The indirect fluorescent antibody (IFA) and ELISA antibody tests (cattle only) were used to examine reactivity to N caninum; the modified direct agglutination, Sabin-Feldman dye, and IFA tests were used to evaluate reactivity to T gondii. RESULTS Serologic cross-reactivity among N caninum, T gondii, and Sarcocystis sp was none or minimal by the IFA test. There was some reactivity to N caninum by the use of ELISA in cattle inoculated with Sarcocystis sp. CONCLUSIONS The IFA test for N caninum was specific for the diagnosis of neosporosis in animals.
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Affiliation(s)
- J P Dubey
- USDA, Livestock and Poultry Sciences Institute, Parasite Biology and Epidemiology Laboratory, Beltsville, MD 20705, USA
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Lindsay DS, Zarlenga DS, Gamble HR, al-Yaman F, Smith PC, Blagburn BL. Isolation and characterization of Trichinella pseudospiralis Garkavi, 1972 from a black vulture (Coragyps atratus). J Parasitol 1996. [PMID: 8544065 DOI: 10.2307/3284041] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
A nematode from the genus Trichinella was observed in histological sections of breast and tracheal muscles from a black vulture Coragyps atratus from Alabama. Larvae obtained from breast muscle tissue that had been refrigerated for 8 days were infectious for laboratory mice. No nurse cell was observed around larvae in the black vulture or in experimentally infected mice examined 7 or 9 wk postinoculation. The identity of the parasite as Trichinella pseudospiralis was confirmed by DNA hybridization using the species-specific probe, pTsp 5.32. Infectivity trials showed that this isolate was also infective for pigs and chickens. This is the first report of isolation and transmission of T. pseudospiralis from an animal from North America.
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Affiliation(s)
- D S Lindsay
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Alabama 36849-5519, USA
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