Stephen C. Barr’s research while affiliated with Cornell University and other places

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Publications (77)


Evaluation of a Rapid Immunochromatographic Dipstick Test for Detection of Antibodies to Trypanosoma cruzi in Dogs Experimentally Infected with Isolates Obtained from Opossums (Didelphis virginiana), Armadillos (Dasypus novemcinctus), and Dogs (Canis familiaris) from the United States
  • Article

February 2011

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78 Reads

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11 Citations

Journal of Parasitology

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Roderick Hill

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Samantha Lewis

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Dogs are reservoir hosts for Trypanosoma cruzi , the causative agent of American trypanosomiasis. A rapid immunochromatographic dipstick test (ICT) is available commercially for canine serological testing. The ICT was developed with the use of sera from South American dogs, but it is not routinely used in the United States. We evaluated the utility of the ICT in detecting anti-T. cruzi antibodies in dogs from the United States. Dogs (N  =  64) were experimentally infected with United States' isolates of T. cruzi from an opossum (Didelphis virginiana), an armadillo (Dasypus novemcinctus), and a domestic dog (Canis familiaris), and were tested after experimental infection. Sera from uninfected United States dogs (n  =  79; hemaculture negative) were used as negative controls. In a blind study, sera were tested by the ICT and compared to the indirect immunofluorescent antibody test with the use of Brazil-strain epimastigotes as antigen. The sensitivity of the ICT was 91% and the specificity was 98% in dogs experimentally infected with United States isolates. Our study indicates that the ICT could be a useful screening tool for serological surveillance of canine T. cruzi exposure in the United States.


Prevalence of Antibodies to Trypanosoma cruzi, Toxoplasma gondii, Encephalitozoon cuniculi, Sarcocystis neurona, Besnoitia darlingi, and Neospora caninum in North American Opossums, Didelphis virginiana, from Southern Louisiana
  • Article
  • Full-text available

December 2010

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132 Reads

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18 Citations

Journal of Parasitology

We examined the prevalence of antibodies to zoonotic protozoan parasites ( Trypanosoma cruzi, Toxoplasma gondii, and Encephalitozoon cuniculi) and protozoans of veterinary importance ( Neospora caninum, Sarcocystis neurona, and Besnoitia darlingi) in a population of North American opossums ( Didelphis virginiana) from Louisiana. Samples from 30 opossums were collected as part of a survey for T. cruzi in Louisiana. Frozen sera from these 30 opossums were examined using an indirect immunofluorescent antibody test (IFAT) against in vitro-produced antigenic stages of these protozoans. Additionally, 24 of the 30 samples were examined using hemoculture, and all 30 were examined in the modified direct agglutination test (MAT) for antibodies to To. gondii. The prevalences of reactive IFAT samples were as follows: 60% for T. cruzi, 27% for To. gondii, 23% for E. cuniculi, 17% for S. neurona, 47% for B. darlingi, and 0% for N. caninum. Hemoculture revealed that 16 (67%) of 24 samples were positive for T. cruzi, compared to 18 of 30 (60%) by IFAT. The sensitivity and specificity for the IFAT compared to hemoculture was 100% for each. The modified direct agglutination test revealed that 9 (30%) of the 30 samples from opossums had antibodies to To. gondii , compared to 8 (27%) using the IFAT. The sensitivity and specificity of the IFAT compared to the MAT was 100% and 72%, respectively.

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Influence of treatment with ultralow-dose aspirin on platelet aggregation as measured by whole blood impedance aggregometry and platelet P-selectin expression in clinically normal dogs

November 2010

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23 Reads

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24 Citations

American Journal of Veterinary Research

To evaluate the influence of treatment with ultralow-dose aspirin (ULDAsp) on platelet aggregation, P-selectin (CD62P) expression, and formation of platelet-leukocyte aggregates in clinically normal dogs. 18 clinically normal dogs. Studies were conducted before and 24 hours after ULDAsp administration (0.5 mg/kg, PO, q 24 h, for 2 days). Whole blood impedance aggregometry for the assessment of platelet function was performed with sodium citrate-anticoagulated blood and aggregation agonists (ADP at 20, 10, and 5 μmol/L; collagen at 10, 5, and 2 μg/mL). Onset, maximum response, and rate of platelet aggregation were recorded. Flow cytometric assays were configured to detect thrombin-induced CD62P expression and platelet-leukocyte aggregates in EDTA-anticoagulated whole blood. Externalized platelet CD62P and constitutive CD61 (GPIIIa) were labeled with antibodies conjugated to phycoerythrin (PE) and fluorescein isothiocyanate (FITC), respectively. Red blood cell-lysed paraformaldehyde-fixed EDTA-anticoagulated whole blood was dual labeled with CD61-FITC and a panleukocyte antibody (CD18-PE) to characterize platelet-leukocyte aggregates. ULDAsp significantly delayed platelet aggregation onset with ADP at 20 μmol/L by 54% to 104%, attenuated maximum aggregation with various concentrations of ADP and collagen by ≥ 41%, and slowed aggregation rate with the highest ADP and collagen concentrations by ≥ 39%. Depending on the parameter tested, up to 30% of dogs failed to have an ULDAsp effect. Thrombin stimulation significantly increased CD62P expression in platelets and platelet-leukocyte aggregates, but ULDAsp did not alter basal or thrombin-stimulated CD62P expression. ULDAsp treatment of clinically normal dogs impaired platelet aggregation in most dogs, but did not influence CD62P platelet membrane expression.



Figure 1. Prevalence of canine visceral Leishmaniasis in the World and United States A. Global seroprevalence of Canine VL. Adapted with permission from Chappuis F, Sundar S, Hailu A, et al. Visceral leishmaniasis: what are the needs for diagnosis, treatment and control? Nat Rev Microbiol. 2007;5(11):873–82.. B. Seroprevalence of CVL in Foxhounds in North America. Adapted from Duprey ZH, Steurer FJ, Rooney JA, et al. Canine visceral leishmaniasis, United States and Canada, 2000–2003. Emerg Infect Dis. 2006 Mar;12(3):440– 6.  
Figure 2. The classical Leishmania life cycle (A) requires both a sand fly and mammalian host. (B) A proposed Leishmania infantum life cycle in the United States Foxhound population with a prominent role for vertical transmission.  
Figure 3. Photomicrograph of numerous Leishmania infantum amastigotes in a section of spleen from a U.S. Foxhound Notice multiple amastigotes within macrophages. A. 40X H&E stain, multiple amastigotes. B. Immunohistochemistry for Leishmania infantum amastigotes (red); bar = 20 μm.  
Figure 3. Photomicrograph of numerous Leishmania infantum amastigotes in a section of spleen from a U.S. Foxhound 
Canine Leishmaniasis in North America: Emerging or Newly Recognized?

November 2009

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1,756 Reads

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86 Citations

Veterinary Clinics of North America Small Animal Practice

Canine leishmaniasis is a fatal zoonotic visceralizing disease usually associated with tropical areas. The etiologic agent is an obligate intracellular protozoan, Leishmania infantum. In 1999, an outbreak of a canine leishmaniasis was reported in a Foxhound kennel in New York, and since that report, several other outbreaks have occurred across the United States in additional Foxhound kennels. Because of the high mortality and transmissibility associated with these outbreaks, it is essential that clinicians be aware of this disease to permit its rapid recognition and institution of control measures. Cases with a travel history may suggest imported disease; these are mainly observed from Southern Europe (eg, south of France, Spain, and Italy). Breeds from these and other endemic areas may be at higher risk of infection with Leishmania because of vertical transmission. The purpose of this report is to discuss the clinical signs, epidemiology, diagnosis, control, and treatment of canine leishmaniasis with focus on the aspects of this disease within North America.


Canine Chagas' Disease (American Trypanosomiasis) in North America

November 2009

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149 Reads

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96 Citations

Veterinary Clinics of North America Small Animal Practice

Chagas' disease, or American trypanosomiasis, caused by the hemoflagellated protozoan Trypanosoma cruzi (class Zoomastigophorea and family Trypanosomatidae), is the leading cause of dilated cardiomyopathy in man. In dogs in North America, Chagas disease mainly occurs in working dogs in southeastern Texas. It is likely that most dogs become infected by eating infected vectors, causing the release of the organisms into the mouth of the host. Most dogs are diagnosed during the chronic stage of the disease, which is typified by dilated cardiomyopathy and malignant ventricular-based arrhythmias. This article reviews the etiology, epidemiology, pathogenesis, diagnosis, and available therapy for Chagas' disease in dogs.


Intestinal Obstruction Caused by Taenia taeniaeformis Infection in a Cat

March 2009

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35 Reads

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15 Citations

Journal of the American Animal Hospital Association

An adult domestic shorthair (DSH) cat was presented with acute vomiting, anorexia, lethargy, and dyspnea. The cat's clinical status worsened over 24 hours with conservative medical management. An exploratory celiotomy was performed. Acute intestinal obstruction resulting from infection with Taenia (T.) taeniaeformis was diagnosed. Surgical removal of the cestodes via multiple enterotomies resolved the obstruction. This paper reports, for the first time, small intestinal obstruction caused by T. taeniaeformis infection in a cat.


Immunogenicity and protective efficacy of recombinant Leptospira immunoglobulin-like protein B (rLigB) in a hamster challenge model

February 2009

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43 Reads

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91 Citations

Microbes and Infection

Leptospiral immunoglobulin-like protein (LigB) was truncated into conserved (LigBcon) and variable (varB1, varB2) fragments and expressed as GST/His-tag fusion proteins. Four-week-old hamsters were immunized with equal amounts of each fragment individually or combined in alum adjuvant at days 0 and 21 and subsequently challenged three weeks after the booster with 2.5 LD(50) live virulent Leptospira interrogans serovar Pomona. Our results demonstrate that immunization with LigB produced strong humoral immune responses as revealed by high titers against each fragment and significant enhancement in Th2 cytokines (IL-4, IL-10). A significant activation of CMI is revealed by enhanced proliferation of lymphocytes and up regulation of Th1 cytokines (IL-12p40, IFN-gamma) was also noted. Of the peptides studied, rLigBcon was able to impart maximum protection (71%), followed by rVarB1 (54%), whereas rVarB2 was not able to impart a significant level of protection (33%) against lethal infection as revealed by enhanced survival and reduced severity of histopathological lesions in vital organs (viz. kidney, liver, spleen) of the immunized animals. Moreover, concurrent administration of all three fragments significantly enhanced the protective efficacy of the vaccine (83%). Overall, our results clearly demonstrate that LigB has emerged as novel protective antigen that can be used in future subunit vaccines against leptospirosis.



Citations (68)


... Oxime derivatives with antimicrobial properties were used as antibiotics in the health field [12][13][14][15][16][17]. Furthermore, some oxime derivatives have parasiticidal properties [18,19]. In addition, oximes were used in arrhythmia, intraocular pressure reduction, and in the treatment of some psychiatric disorders [20][21][22]. ...

Reference:

Determination of 1 H and 13 C Nuclear Magnetic Resonance Chemical Shift Values of Glyoxime Molecule with Experimental and Theoretical Methods
Treatment of experimentally induced trichinosis in dogs and cats
  • Citing Article
  • August 1993

American Journal of Veterinary Research

... While the role of canids in the transmission cycle of L. serrata is well defined, the position of felids and especially that of domestic cats appears to be not that clear. Interestingly, the comprehensive textbook on feline parasitology of Bowman et al. [85] does not notice L. serrata as a parasite of cats at all but refers only to nymphal infestations with the pentastomid Armillifer armillatus whose adults reside in the respiratory tract of large snakes. There are publications which list cats as both final and intermediate hosts of L. serrata [86] or mention cats as final hosts of L. serrata (among others, [54,67,[87][88][89]) or consider felids generally as non-competent final hosts of L. serrata [2]. ...

Feline Clinical Parasitology
  • Citing Book
  • April 2008

... circulating antibodies in the blood. Other tests have been developed, such as enzymelinked immunosorbent assays (ELISA), complement fixation, Western blot analysis, and other agglutination assays; however, none of them has a high specificity and sensitivity [23]. ...

Leishmaniasis in American foxhounds: An emerging zoonosis?

Compendium on Continuing Education for the Practising Veterinarian -North American Edition-

... 5 However, accuracy of microscopic diagnosis of G. duodenalis is limited by the infrequent presence of trophozoites in diarrheic feces, intermittent passage of cysts, and the requirement that an experienced technician perform the examination. [6][7][8] The direct immunofluorescent assay (IFA) is more sensitive and specific for diagnosing G. duodenalis than conventional flotation tests 9,10 and is the reference test for evaluating G. duodenalis tests in companion animals. 4,11,12 Immunoassays are also available that detect a soluble cyst antigen of G. duodenalis. ...

Giardiasis in dogs and cats
  • Citing Article
  • January 1994

... Adult metastrongyloids differ in size indicating their localisation in the lung and/or heart of their definitive host. Adult A. abstrusus are the smallest common feline metastrongyloids with 5-10 mm length and 60-80 µm width [13], inhabiting the alveolar ducts and bronchioles [14]. Adult T. brevior are larger (5-13 mm long, 0.3-0.4 ...

Feline Clinical Parasitology
  • Citing Article
  • June 2002

Journal of Parasitology

... Dilutional hyponatremia caused by excessive water accumulation in body having characteristic feature of hypotonicity, hyposmolarity and hypervolemia. However, few reports of this malady can be traced back in felines and canine (Toll et al., 1999;Evenchen et al., 2010;Lee et al., 2013). This form of hyponatremia usually develops when the amount of water exceeds the capacity of kidneys to filter and excrete even after the suppression of ADH (Adrogué and Madias, 2000). ...

Acute Water Intoxication in a Dog
  • Citing Article
  • March 1999

... The large diversity of antigens in use (e.g., whole trypanosomes, semi-purified preparations, recombinant proteins, and synthetic peptides) affects the validity of tests. Some dipstick tests were very helpful for screening serosurveys of dog populations (Cardinal et al. 2006b;Nieto et al. 2009;Rosypal et al. 2011;Lizundia et al. 2014). In a large sample of naturally infected dogs, the sensitivity of the dipstick test was >96% and specificity >94% (Cardinal et al. 2006a). ...

Evaluation of a Rapid Immunochromatographic Dipstick Test for Detection of Antibodies to Trypanosoma cruzi in Dogs Experimentally Infected with Isolates Obtained from Opossums (Didelphis virginiana), Armadillos (Dasypus novemcinctus), and Dogs (Canis familiaris) from the United States
  • Citing Article
  • February 2011

Journal of Parasitology

... These lesions have been reported in D. marsupialis in natural and experimental infections (Prestwood 1976, Prestwood et al. 1977 and in D. virginiana (Lamberski et al. 2002, Nichelason et al. 2008, Jones 2013 in the United States of America, as well as in D. aurita in Brazil (Costa-Neto et al. 2019). Infection with Besnoitia darlingi has been reported from D. virginiana in several states of the United States of America (Kentucky, Louisiana, Missouri, Illinois, Indiana, Texas, and Kansas City) (Shaw et al. 2009, Houk et al. 2010. Besnoitia infections that do not cause disease have been reported, but mortality only in animals with stress, immunosuppression, or concurrent parasitic infections (Ellis et al. 2012). ...

Prevalence of Antibodies to Trypanosoma cruzi, Toxoplasma gondii, Encephalitozoon cuniculi, Sarcocystis neurona, Besnoitia darlingi, and Neospora caninum in North American Opossums, Didelphis virginiana, from Southern Louisiana

Journal of Parasitology

... It is unknown, however, if clopidogrel resistance occurs, but platelet response heterogeneity has already been observed in healthy dogs. [19][20][21] Because of resistance, it is generally agreed upon in human medicine that monitoring of treatment response using platelet function testing (PFT) is indicated, but specific protocols have not been determined. 18 Additionally, people with kidney disease, particularly those with chronic kidney disease (CKD) can have a decreased response to antiplatelet treatment, but it is unknown if a similar effect occurs in dogs with renal disease such as those with PLN. ...

Influence of treatment with ultralow-dose aspirin on platelet aggregation as measured by whole blood impedance aggregometry and platelet P-selectin expression in clinically normal dogs
  • Citing Article
  • November 2010

American Journal of Veterinary Research

... Techniques for intranasal clotrimazole 426 infusion in cats are similar to those used for treatment of canine SNA with slight 427 modifications (Furrow and Groman 2009; Tomsa et al. 2003; Peeters and Clercx 428 2007). Polypropylene glycol must not be used as the vehicle for clotrimazole as it 429 can cause severe mucosal oedema and ulceration(Barr et al. 2010). Polyethylene 430 glycol is a safe vehicle for clotrimazole infusion. ...

Questions contents of clotrimazole solution
  • Citing Article
  • January 2010

Journal of the American Veterinary Medical Association