Epidemiological survey of Angiostrongylus vasorum in dogs and slugs around a new endemic focus in Scotland

Abstract

The nematode parasite Angiostrongylus vasorum is an increasingly important cause of respiratory and other diseases in dogs. Geographical spread from previously limited endemic foci has occurred rapidly. This paper investigates parasite epidemiology around the location of the first reported case in Scotland in 2009: by detection of A vasorum-specific DNA in gastropod intermediate hosts, and in dogs circulating DNA and specific antibodies, and first stage larvae in faeces. Overall prevalence in gastropods was 6.7 per cent (16/240), with parasite DNA found in slugs in the Arion ater and Arion hortensis species aggregates and the snail Helix aspersa (syn. Cornu aspersum). Of 60 dogs presenting with clinical signs compatible with angiostrongylosis, none tested positive using PCR on peripheral blood or Baermann test on faeces, and none of 35 tested for circulating anti-A vasorum antibodies were positive. PCR prevalence in gastropods was highest (11 per cent) in the park frequented by the canine angiostrongylosis index case. Molecular survey for infection in gastropods is a potentially informative and efficient method for characterising the distribution of A vasorum and therefore local risk of canine infection. However, there appears to be a complex relationship between prevalence in gastropods and emergence of canine clinical disease, which requires further work to advance understanding of parasite transmission and geographical disease spread.

Seroepidemiological survey and spatial analysis of the occurrence of Angiostrongylus vasorum in Swiss dogs in relation to biogeographic aspects

“…Primarily slug species were naturally infected, especially Arion spp. (rufus, lusitanus, ater, distinctus), Limax maximus and Tandonia sowerbyi (Guilhon and Bressou, 1960;Eckert and Lämmler, 1972;Ferdushy et al, 2009;Patel et al, 2014), and recently also the snail Helix aspersa was found PCR-positive for A. vasorum (Helm et al, 2015). The occurrence of these species is acknowledged also for Switzerland (with the exception of T. sowerbyi), and their natural habitat is mostly situated at altitudes from 200-1100 m asl, though they can also be found at altitudes as high as 2000 m asl (Boschi, 2011).…”

GIS-supported epidemiological analysis on canine Angiostrongylus vasorum and Crenosoma vulpis infections in Germany

“…dispersal of juvenile animals), dogs (e.g. travelling) and intermediate hosts as already discussed by others [ 13 , 14 ]. However, further studies are needed to understand the contribution of environmental factors as well as different species of intermediate and final hosts to the epidemiology of lungworm infections.…”

Slugs and Angiostrongylus vasorum – how much do we know?

“…Under field conditions, the number of L1 acquired by a slug (and the number of slugs ingested by the final hosts) cannot be determined. Nevertheless, the coprophagic behaviour of some Arionidae species (Boschi 2011) together with their large size can result in higher larval burdens (Patel and others 2014), confirming their importance (Helm and others 2015). …”

“…The first endemic case in a dog in Scotland was described in 2009 (Helm and others 2009). A study by Helm and colleagues (2015), summarised on p 46 of this issue of Veterinary Record , reports on the occurrence of A vasorum in slugs. Of the intermediate hosts collected in three defined areas around Glasgow, 6.7 per cent were positive for A vasorum DNA.…”