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

Exploring similarities and differences between Toxoplasma gondii and Neospora caninum infections in dogs

Toxoplasma gondii and Neospora caninum infections in dogs are predominantly manifest asymptomatic. However, these infections can also present highly varied and potentially severe clinical signs. This is due to the parasites' ability to replicate in a number of cell types within the host organism, with N. caninum exhibiting a particular tropism for the central and peripheral nervous systems, and T. gondii targeting the central nervous system and musculature. In clinical practice, toxoplasmosis and neosporosis are often considered to be closely related diseases, despite their distinct epidemiological, clinical, diagnostic, and therapeutic characteristics. The present review analyses the similarities and differences between these two protozoan infections, since an accurate and timely aetiological diagnosis is essential for establishing effective therapeutic protocols and control strategies.

Insights into the clinical presentation, diagnostics and outcome in dogs presenting with neurological signs secondary to infection with Neospora caninum: 41 cases (2014-2023)

OBJECTIVES

To describe the clinical signs and outcome of a large cohort of dogs presenting with neurological signs secondary to Neospora caninum infection.

MATERIALS AND METHODS

Retrospective review of cases presenting to two UK referral centres with neurological signs secondary to N. caninum infection between 2014 and 2023. Presenting signs, diagnostic test results, treatment, short- and long-term outcome analysed.

RESULTS

A total of 1690 cases were assessed for eligibility. Forty-four cases with a diagnosis of neosporosis were obtained. Three cases were then excluded due to non-neurological presentations (two hepatitis and one myocarditis). A total of 41 cases were included in the study. Cerebello-vestibular signs predominated; however, presenting clinical signs were varied and the neurolocalisation was often multifocal in nature (46.3%), making neosporosis an important differential diagnosis for meningoencephalitis of unknown origin. Complete clinical improvement was rare (5.6%), and relapses were common (27.8% cases with follow-up).

CLINICAL SIGNIFICANCE

Neosporosis remains an important differential diagnosis for dogs at any age presenting with multifocal neurological signs. The outcome is considered poor and relapse rate is high.

Seroprevalence of Neospora caninum in pet cats, dogs and rabbits from urban areas of Poland

BACKGROUND

Neospora caninum (N. caninum) has a broad intermediate host range and might cause multisystemic lesions in various species of animals. Dogs are both intermediate and definitive hosts of the parasite and play a crucial role in the horizontal transmission of this protozoan to other animals. Cats and rabbits could be sensitive to infection with N. caninum, however, clinical symptoms and the exact route of infection in these species are unknown. The epidemiology of N. caninum in cats and rabbits has been barely researched, and there is no published record of the seroprevalence of N. caninum infection in these species in Poland. Thus, the present study aimed to determine the frequency of seroreagents for N. caninum within pet dogs, cats and rabbits from urban areas of Poland and to identify possible risk factors for these animals.

RESULTS

In total, serum samples from 184 cats (Felis catus), 203 dogs (Canis familiaris) and 70 rabbits (Oryctolagus cuniculus) were used in the study. The seroprevalence of anti-N. caninum antibodies in dogs and cats reached 1.0% (2/203; 95% CI: 0.3-3.5) and 3.3% (6/184; 95% CI: 1.5-6.9), respectively. No significant differences in seroprevalence regarding age group, gender, symptoms or sampling location were found. All 70 samples from pet rabbits were negative for anti-N. caninum antibodies.

CONCLUSIONS

The seroprevalence rates of N. caninum in dogs and cats in the present study were low, however, our results confirmed N. caninum circulates among dog and cat populations in Poland, and neosporosis should be included in the differential diagnosis of neuro-muscular disorders in these species. This is the first serological survey of N. caninum in European pet cats and rabbits. The role of pet rabbits in N. caninum epidemiology and circulation in Poland is marginal.

American Canine Hepatozoonosis Causes Multifocal Periosteal Proliferation on CT: A Case Report of 4 Dogs

American canine hepatozoonosis (ACH) represents an important but relatively uncommon differential diagnosis in a dog with fever, muscle wasting, profound leukocytosis, and/or musculoskeletal pain. Despite this, obtaining a definitive diagnosis can prove difficult. Peripheral blood smears and whole-blood polymerase chain reaction (PCR) rely on rare parasitemia, and the gold standard diagnostic test (skeletal muscle biopsy) is uncommonly pursued due to its invasive and costly nature. Demonstration of characteristic periosteal proliferative lesions aids diagnosis. The lesions typically involve the more proximal long bones of the appendicular skeleton. The periosteal proliferation is of currently unknown pathogenesis, but its distribution is characteristic of this disease with few differential diagnoses. This case series describes the findings on computed tomography (CT) in 4 dogs with PCR- or cytologically-confirmed Hepatozoon americanum. All dogs had multifocal, bilaterally asymmetric, irregularly marginated, non-destructive, non-articular, periosteal proliferative lesions. Recognition of this unusual CT finding and awareness of this disease could assist in the diagnosis and subsequent treatment of dogs with ACH and may offer an additional indication for CT in cases of fever, muscle wasting, and myalgia.