Evaluation of a rapid device for serological in-clinic diagnosis of canine angiostrongylosis

Parasit Vectors. 2014 Feb 18:7:72. doi: 10.1186/1756-3305-7-72.

Abstract

Background: Angiostrongylus vasorum is a potentially fatal canine nematode. Due to the high variability of clinical signs and the often chronic and subtle course of the infections, the diagnosis is particularly challenging. A rapid in-clinic assay (Angio Detect Test, IDEXX Laboratories, Westbrook, Maine, USA) for the serological detection of circulating antigen and intended for routine in-clinic diagnosis has been evaluated.

Methods: Sensitivity was calculated with sera from 39 naturally infected dogs confirmed by Baermann-Wetzel analysis, while sera of 38 experimentally infected dogs were used for follow-up analyses, of which 10 were treated with imidacloprid/moxidectin. Cross-reactivity was tested with a total of 123 samples from dogs with proven parasitic infections with Toxocara canis (n = 21), Ancylostoma caninum (n = 4), Crenosoma vulpis (n = 18), Oslerus osleri (n = 3), Eucoleus aerophilus, (n = 6), Dirofilaria immitis (n = 28), Dirofilaria repens (n = 20), Acantocheilonema reconditum (n = 10) or Dipetalonema dracunculoides (n = 10) or multiple infections (n = 3). All sera were tested with the Angio Detect Test and with an ELISA for detection of circulating antigen of A. vasorum.

Results: The sensitivity of the Angio Detect Test was 84.6% (95% C.I. 69.5 - 94.1%), while specificity was 100% (95% C.I. 97.6 - 100%). The sensitivity of the ELISA (94.9%, 95% C.I. 82.7 - 99.3%) was comparable with previous evaluations. In experimentally infected dogs, earliest positive results with the Angio Detect Test were observed 9 weeks post inoculation and 5 weeks later all sera were Angio Detect Test positive. After anthelmintic treatment, seropositive dogs turned negative again within 3 to 7 weeks after treatment. The evaluation of the colour intensity of the test strips confirmed the delay of approximately 3-4 weeks for antigen detection by the Angio Detect™ Test compared to the ELISA and its correlation with the time after infection.

Conclusions: This study provided evidence of a good sensitivity and a very high specificity of the rapid device Angio Detect Test for detection of circulating A. vasorum antigen in dogs with suspected canine angiostrongylosis, representing a very simple and useful tool to be broadly applied in veterinary practices. The rapid detection of infected dogs is a key point for initiating an indispensable and urgent therapy.

Publication types

  • Evaluation Study

MeSH terms

  • Angiostrongylus / immunology*
  • Angiostrongylus / isolation & purification
  • Animals
  • Antigens, Helminth / blood*
  • Dog Diseases / diagnosis*
  • Dog Diseases / parasitology
  • Dogs
  • Enzyme-Linked Immunosorbent Assay / methods
  • Enzyme-Linked Immunosorbent Assay / veterinary*
  • Female
  • Reagent Kits, Diagnostic
  • Sensitivity and Specificity
  • Strongylida Infections / diagnosis
  • Strongylida Infections / parasitology
  • Strongylida Infections / veterinary*
  • Time Factors

Substances

  • Antigens, Helminth
  • Reagent Kits, Diagnostic

Supplementary concepts

  • Angiostrongyliasis