Prevalence of selected infectious diseases in Samoan dogs : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Science at Massey University, Manawatu, New Zealand
Samoa has a tropical island climate ideally suited to many infectious diseases, and vectors for some infectious diseases are known to be present. Dogs are very commonly owned in Samoa with 88% of households owning an average of two dogs. Many canine infectious diseases are zoonotic and there is limited preventative medicine available for dogs in Samoa. There are very few studies into the presence of zoonotic pathogens in Samoa or other South Pacific islands, and the role of dogs as a reservoir for zoonotic diseases is unknown.
The prevalence of selected infectious diseases was evaluated in 242 dogs undergoing surgical sterilisation in Samoa in July 2010 and August 2011. Data were obtained from dogs’ owners by interview, including age, environment and any previous preventative medication. Serum and faecal samples were collected, and the skin examined for external parasites. Seroprevalence of Leishmania infantum, Anaplasma phagocytophilum, Ehrlichia canis, Borrelia burgdorferi and Dirofilaria immitis were assessed using point of care qualitative ELISA assays. Faecal flotation was performed on fresh faecal samples to screen for intestinal parasites. Ninety-three faecal samples were also tested for Giardia and Cryptosporidium spp.
The median age of dogs was one year, with a range of four months to eight years and 73.3% were male. The vast majority of dogs were owned, the remaining were stray animals. Prevalence of D. immitis was 46.8% and A. phagocytophilum seroprevalence was 8.4%. All serum samples tested negative for E. canis, B. burgdorferi and L. infantum. Prevalence of hookworm was 92.6%. Trichuris vulpis, Dipylidium caninum, Toxocara canis and Capillaria spp. were also detected. Prevalence of Giardia spp. was 29.0% while no Cryptosporidium was detected. Fleas were found on 83.7% of the dogs, ticks on 42.1% and lice on 8.1%. Identified ticks were Rhipicephalus sanguineus, with no Ixodes spp. found.
The results indicate a very high prevalence of hookworm, D. immitis, and external parasites in Samoan dogs. This study provides valuable information on canine health and suggests dogs could play a role in the spread of some zoonoses in Samoa. Further studies are required to review the public health implications of this study.