High seroprevalance of Neospora caninum in dogs in Victoria, Australia, compared to 20 years ago

Abstract

BackgroundCanids are definitive hosts of the apicomplexan parasite Neospora caninum, the leading cause of abortion in cattle worldwide. For horizontal transmission from canids to occur, oocysts of N. caninum must be shed by the definitive host into the environment of susceptible intermediate hosts such as cattle. The purpose of this study was to determine the prevalence of N. caninum in canids in Victoria, Australia’s leading dairy producing state.Results Neospora-like oocysts were observed in 8% (18/234) of faecal samples from wild dogs, domestic dogs and red foxes from Victoria, Australia. However, none tested positive for N. caninum DNA using a quantitative PCR. In a separate sample population, blood sera from 483 domestic dogs were tested for anti-N. caninum antibodies using competitive ELISA. A subset of cELISA samples were re-tested using indirect fluorescence antibody test (IFAT). A seroprevalence of 29.8% (144/483; 95% CI: 11.7–47.8%) was calculated when using cELISA; whereas it was 32.9% (27/80; 95% CI: 15.8–51.8%) using IFAT. Potential risk factors were evaluated using univariable analyses and then assessed in separate multivariable models. Using ‘aged’ dogs as a reference, the seroprevalence of ‘adolescent’ and ‘adult’ dogs was 88% (P = 0.05) and 91% (P = 0.08), respectively, indicating seroprevalence increases with age. There was a 19% higher likelihood of infection in rural locations (P = 0.10) relative to urban areas. Jack Russell Terriers had a 22% higher risk of a cELISA-positive result (P = 0.05) regardless of geographical location, age or sex.ConclusionThese results demonstrate that exposure to N. caninum in domestic dogs is widespread in Victoria, although faecal oocyst shedding is infrequent. Our results indicate increased N. caninum seroprevalance status in dogs over the past two decades. The results imply that dogs get either exposed to the infected meat more frequently or that vertical dam to foetus transmission is more frequent than previously thought. Our study calls for re-evaluation of historical N. caninum seroprevalance studies, because the attitude to dog diet changes.Electronic supplementary materialThe online version of this article (10.1186/s13071-017-2464-2) contains supplementary material, which is available to authorized users.

Seroprevalence of Neospora caninum in dogs from greater Sydney, Australia unchanged from 1997 to 2019 and worldwide review of adult-onset of canine neosporosis

“…(1997) . We could not confirm the hypothesised increase in the N. caninum seroprevalence in Sydney, New South Wales, since 1997, based on a six-fold increase in N. caninum seroprevalence recently demonstrated for dogs in Melbourne, Victoria ( Sloan et al., 2017 ). The knowledge of the seroprevalence is of equal value when treating animals with immunosuppressive drugs which is common for a wide variety of non-neosporosis related canine diseases.…”

“…Seroprevalence of anti- N. caninum IgG was established for domestic dogs in Melbourne, Perth and Sydney in 1997 ( Barber et al., 1997 ). Seroprevalence in Melbourne was recently demonstrated to increase from 5% in 1997 to 34% in 2017 ( Sloan et al., 2017 ). This rise in seroprevalence means a higher proportion of dogs at risk of developing adult-onset canine neosporosis as a consequence of recrudescence of N. caninum .…”

Survival time and relapse in dogs with meningoencephalomyelitis of unknown origin treated with prednisolone and ciclosporin: a retrospective study

“…The prevalence of active infection with Cryptococcus , Neospora , and Toxoplasma in this population is unknown. The seroprevalence of N. caninum in dogs sampled across Victoria in 2017 was ~30% (29.8% using cELISA and 32.9% using IFAT) indicating that many dogs in this region may have been exposed 39 . Faecal oocyst shedding was not detected and no dogs in the aforementioned study were reported to have any clinical signs suggestive of active infection with N. caninum 39 .…”

“…The seroprevalence of N. caninum in dogs sampled across Victoria in 2017 was ~30% (29.8% using cELISA and 32.9% using IFAT) indicating that many dogs in this region may have been exposed 39 . Faecal oocyst shedding was not detected and no dogs in the aforementioned study were reported to have any clinical signs suggestive of active infection with N. caninum 39 . A recent study looking at the prevalence of protozoal infection in suspected MUO cases in the UK reported an exposure prevalence of 3.98% and 6.96% for T. gondii and N. caninum respectively.…”

Detección de anticuerpos contra Neospora caninum en caninos del área urbana y rural de Cumaral, Meta-Colombia

“…Con respecto a la seropositividad de acuerdo con la edad, la mayor positividad fue observada en los animales jóvenes (40%) que coincide con los datos reportados, en perros de Victoria, Australia, sin embargo en el grupo de adultos se encontró la mayor prevalencia (28). La raza, sexo y edad, no fueron factores asociados a la seroprevalencia , como se observó en caninos del área central de China (23).…”