12
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Repeated inoculations with the lung and heartworm nematode Angiostrongylus vasorum result in increasing larval excretion and worm burden in the red fox ( Vulpes vulpes)

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          The French heartworm Angiostongylus vasorum is found in European red fox ( Vulpes vulpes) and dog populations, where it appears to be spreading geographically. Once introduced into new areas, it establishes in local fox populations, typically to over 50% prevalence in a few years. High susceptibility and constant excretion of first stage larvae (L1) by the definitive hosts are prerequisites for sustaining high parasite biomass in a particular habitat. The present study explores the hypothesis that repeated ingestion of gastropods in nature will result in accumulation of adult worms and elevated excretion of L1 in feces. Experimentally infected foxes were subsequently inoculated via stomach tube once (9 weeks post initial inoculation) or twice (9 and 13 weeks post inoculation (wpi)) with 100 third stage A. vasorum larvae (L3) previously isolated from aquatic snails infected with L1 from a naturally infected dog. Despite large variation in fecal larval excretion for the individual animals within the groups, excretion of L1 was significantly higher in foxes twice inoculated as compared to foxes inoculated only once. With an outlier in the once inoculated group removed, excretion became significantly higher in the three times inoculated group. Establishment of adult worms varied and only a trend to higher worm burdens was found in the group of foxes inoculated three times. However, this became significant with the same single outlier removed. Overall, it appears that protective immunity to A. vasorum does not appear to occur in V. vulpes with animals exhibiting high infection intensities without obvious clinical signs. The increasing larval excretion in foxes being repeatedly exposed to A. vasorum L3 support the hypothesis that foxes under natural conditions may repeatedly ingest infected gastropods and remain a source of environmental contamination for several months, potentially contributing to the establishment of endemic foci through increasing L1 excretion.

          Graphical abstract

          Highlights

          • Foxes were experimentally infected with 100 Angiostrongylus vasorum larvae (L3).

          • Two groups were later challenged once or twice.

          • Increasing larval counts linked to time post infection and repeated inoculation.

          • Data suggests role of foxes in rapid establishment of the parasite in new areas.

          Related collections

          Most cited references46

          • Record: found
          • Abstract: found
          • Article: not found

          Angiostrongylus vasorum infection in 23 dogs (1999-2002).

          Angiostrongylosis was diagnosed in 23 dogs presenting to the Queen Mother Hospital for Animals between June 1999 and August 2002. The animals' clinical records were reviewed retrospectively and certain risk factors were compared with a control population of 3407 dogs. Twenty-two of the 23 dogs were from south-east England and dogs from Surrey (n=8) were significantly overrepresented. There were also significantly more Cavalier King Charles spaniels (n=5) and Staffordshire bull terriers (n=5) among the affected dogs than in the control group. The median age of affected dogs was 10 months (range five to 90 months). The most common presenting signs were cough (65 per cent), dyspnoea (43 per cent), haemorrhagic diathesis (35 per cent) and collapse (26 per cent). Four dogs were thrombocytopenic and eight had significant prolongations in prothrombin time and/or activated partial thromboplastin time. Thoracic radiographs were abnormal in 18 of 19 dogs. A variety of changes were observed, the most typical being a patchy alveolar-interstitial pattern affecting the dorsocaudal lung fields. Angiostrongylus vasorum larvae were found in seven of 10 bronchoalveolar lavage specimens and 19 of 19 faecal samples. Three dogs died shortly after admission to the hospital. The remainder were successfully treated with fenbendazole at a dose of 50 mg/kg for five to 21 days. A vasorum should now be considered endemic to south-east England.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Canine pulmonary angiostrongylosis: the influence of climate on parasite distribution.

            The geographic range of Angiostrongylus vasorum is expanding, leading to increased disease. Although observed cases of canine pulmonary angiostrongylosis have been dutifully reported in the literature, the state of biological knowledge remains too poor to predict future patterns of spread with any confidence. Nevertheless, there is an urgent need to identify areas that are likely to be suitable for parasite establishment. Preliminary attempts to do this using a climatic envelope approach suggest that several new areas are open to colonisation, even without invoking climate change. The risk of parasite importation into these areas should be mitigated, e.g. by restricting movement of dogs unless tested or treated for A. vasorum, and monitored by focused surveillance of definitive and intermediate hosts. These efforts will benefit from newly developed diagnostic tests.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Clinical, laboratory and pathological findings in dogs experimentally infected with Angiostrongylus vasorum.

              The aim of this comparative study was to investigate the development of clinical signs and accompanying haematological, coproscopic and pathological findings as a basis for the monitoring of health condition of Angiostrongylus vasorum infected dogs. Six beagles were orally inoculated with 50 (n=3) or 500 (n=3) A. vasorum third stage larvae (L3) obtained from experimentally infected Biomphalaria glabrata snails. Two dogs were treated with moxidectin/imidacloprid spot-on solution and two further dogs with an oral experimental compound 92 days post infection (dpi), and were necropsied 166 dpi. Two untreated control dogs were necropsied 97 dpi. Prepatency was 47-49 days. Dogs inoculated with 500 L3 exhibited earlier (from 42 dpi) and more severe respiratory signs. Clinical signs resolved 12 days after treatment and larval excretion stopped within 20 days in all four treated dogs. Upon necropsy, 10 and 170 adult worms were recovered from the untreated dogs inoculated with 50 and 500 L3, respectively. Adult worms were also found in two treated dogs, in the absence of L1 or eggs. Despite heavy A. vasorum infection load and severe pulmonary changes including vascular thrombosis, only mild haematological changes were observed. Eosinophilia was absent but the presence of plasma cells was observed. Neutrophilic leucocytes showed a transient increase but only after treatment. Signs for coagulopathies were slight; nevertheless coagulation parameters were inoculation dose dependent. Ten weeks after treatment pulmonary fibrosis was still present. Infections starting from 50 L3 of A. vasorum had a massive impact on lung tissues and therefore on the health of affected dogs, particularly after prepatency, although only mild haematological abnormalities were evident.
                Bookmark

                Author and article information

                Contributors
                Journal
                Int J Parasitol Parasites Wildl
                Int J Parasitol Parasites Wildl
                International Journal for Parasitology: Parasites and Wildlife
                Elsevier
                2213-2244
                24 June 2017
                December 2017
                24 June 2017
                : 6
                : 3
                : 139-145
                Affiliations
                [a ]Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
                [b ]Parasitology and Aquatic Diseases, Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
                [c ]Institute of Parasitology, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 266a, 8057 Zurich, Switzerland
                Author notes
                []Corresponding author. Section for Organismal Biology, Department of Plant and Environmental Sciences, University of Copenhagen, Science, Thorvaldensensvej 40, DK-1871 Frederiksberg C, Denmark.Section for Organismal BiologyDepartment of Plant and Environmental SciencesUniversity of Copenhagen, ScienceThorvaldensensvej 40Frederiksberg CDK1871Denmark ian.woolsey@ 123456vetinst.no
                Article
                S2213-2244(16)30045-1
                10.1016/j.ijppaw.2017.06.005
                5502791
                7b90de9b-f286-4cc5-aeb4-d1f447334fb1
                © 2017 Published by Elsevier Ltd on behalf of Australian Society for Parasitology.

                This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

                History
                : 26 October 2016
                : 15 May 2017
                : 22 June 2017
                Categories
                Article

                foxes,angiostrongylus vasorum,experimental inoculation,immunology,larval excretion,worm burden

                Comments

                Comment on this article