Acute onset of encephalomyelitis with atypical lesions associated with dual infection of Sarcocystis neurona and Toxoplasma gondii in a dog

Toxoplasma gondii and Neospora caninum infection in epileptic dogs

OBJECTIVES

Studies in humans have demonstrated the role of Toxoplasma gondii, a protozoan parasite, in epileptic seizures. This study aimed to investigate the serological correlation between T. gondii and N. caninum and epilepsy in dogs.

MATERIALS AND METHODS

The medical record database of the Veterinary Teaching Hospital, University of Perugia, was searched for dogs serologically tested by IFAT for T. gondii and N. caninum and following specific inclusion criteria. Dogs were stratified by having a clinical diagnosis of epilepsy or suffering different conditions.

RESULTS

One-hundred and twenty-eight dogs were included, 64 with epilepsy and 64 without clinical signs of epilepsy. Seventeen of the 64 epileptic dogs (26.6%; 95% CI: 15.7% to 37.4%) and twenty-one of the 64 non-epileptic dogs (32.8%; 95% CI: 21.3% to 44.3%) tested positive for T. gondii. Eight of the epileptic dogs (12.5%; 95% CI: 4.4% to 20.6%) and three of the non-epileptic dogs (4.7%; 95% CI: 0% to 9.9%) tested positive for N. caninum. There was no statistically significant difference in the rate of T. gondii or N. caninum seroreactivity between epileptic and non-epileptic dogs.

CLINICAL SIGNIFICANCE

The results obtained do not seem to support the role of T. gondii and N. caninum as causative agents of dog epilepsy.

Molecular identification of Sarcocystis neurona in tissues of wild boars (Sus scrofa) in the border region between Brazil and Uruguay

Sarcocystis neurona, owing to its clinical importance in domestic animals, is currently one of the most studied agents, presenting a wide range of intermediate hosts that have not yet been described, mainly in wild fauna. Thus, the aim of this study was to describe the detection and molecular detection of S. neurona by amplification of the 18S rRNA region in the tissues of wild boars killed by boar control program in border Brazil Uruguay. A total of 79 samples of DNA from wild boar tissues from the LADOPAR/UFSM sampling bank were used, with Nested-PCR reactions being performed for amplification of the 18S rRNA region and the expected final product of 290 bp. Subsequently, the positive samples were subjected to restriction fragment length polymorphism (RFLP) technique with the restriction enzymes DdeI and HPAII. A second semi-Nested reaction was performed to obtain a larger sequence of nucleotides with amplification of the 18S region and the expected final product of 500 bp for S. neurona and Nested amplification ITS1 with product final of 367 pb. In 32 samples, it was possible to detect S. neurona both by nested Nested-PCR reaction and RFLP, and the presence of the agent was confirmed by sequencing, corresponding to 40.51% of the total tissues evaluated. This is the first report of the occurrence of this species of Sarcocystis in wild boars, and further studies evaluating the role of these animals as intermediate hosts, and in the epidemiology of this protozoan are necessary, as well as verifying the risk factors for infection.

CLINICOPATHOLOGICAL FEATURES OF TOXOPLASMOSIS IN FOUR RED PANDAS (AILURUS FULGENS)

Two geriatric red pandas (Ailurus fulgens) over a 4-yr period presented with vague clinical signs including anorexia, lethargy, and difficulty ambulating. Treatment protocols using enrofloxacin, steroids, and clindamycin were unsuccessful. Necropsy examination confirmed disseminated toxoplasmosis infection in these cases, and a modified agglutination test had been positive for a prolonged period of time before one panda showed signs of disease. A review of the Red Panda Species Survival Plan pathology database revealed two additional cases of disseminated toxoplasmosis in geriatric red pandas. Many organ systems were affected, but dissemination to the brain, lungs, and liver predominated. Immunohistochemistry or polymerase chain reaction was required to confirm a diagnosis in serologically positive animals, as well as in animals in which a histological diagnosis was suspected. This case series describes the clinical and pathological features of toxoplasmosis in geriatric red pandas.

Serologic reactivity of canine sera to Sarcocystis neurona and Sarcocystis cruzi antigens

Sarcocystis neurona, a coccidian parasite shed by opossums (Didelphis spp.) in the Americas, is the major cause of equine protozoal myeloencephalitis (EPM) and induces disease in other domestic and wild animal species, including domestic dogs. Sarcocystis cruzi, despite its low pathogenicity for cattle (intermediate hosts), is worldwide distributed and uses mostly dogs as definitive hosts. The aims of this study were to test serological reactivities of dog sera to S. neurona and S. cruzi antigens, and to investigate potential serological cross-reactivity to these parasites. Sera from 353 Brazilian dogs were obtained from rural areas in the municipality of Ilhéus, Bahia, and examined by immunofluorescent antibody tests (IFAT). Antigens used in serological reactions consisted of S. neurona merozoites from a North American strain (SN138), and bradyzoites of S. cruzi obtained from Brazilian bovine hearts, with parasite species identity confirmed by PCR and sequencing of the 18S gene of the rDNA. Seropositivity to S. neurona and to S. cruzi were detected in 3.39% (12/353) and 4.81% (17/353) of the dogs, respectively. Ten canine sera reacted solely to S. neurona and 15 serum samples reacted only to S. cruzi. Two serum samples were simultaneously positive for both parasites. Sera from 14 dogs that tested positive by IFAT (9 for S. neurona and 3 for S. cruzi) and from two dogs that were negative by IFAT for the two parasites, were examined by Western blot using S. neurona as antigen; these sera reacted to a great number of protein bands, including antigens on the 16 and 30 KDa positions, which encompass immunodominant antigens for S. neurona in horses. Western blot did not show any specific pattern for S. neurona infection/exposure using canine sera. Dogs act as definitive hosts for several Sarcocystis spp. that infect farm animals, including horses, sheep, goats, water buffaloes and pigs, and for this reason, should contain antibodies to a broad repertoire of Sarcocystis spp. antigens. In conclusion, low percentages of dogs from rural areas of Ilhéus, Bahia, were reactive to both S. neurona and S. cruzi antigens. It is possible that other Sarcocystis species, besides S. neurona and S. cruzi, might have contributed for the seropositivity observed in this study. IFAT was more specific than Western blot to differentiate canine serological reactions to S. neurona and S. cruzi antigens.

Clinical Toxoplasmosis in Dogs and Cats: An Update

Toxoplasmosis is caused by the globally distributed protozoan parasite Toxoplasma gondii (phylum Apicomplexa); the disease can be clinically important for almost all homeothermic animals, including birds and humans. Toxoplasmosis course involves general clinical signs, such as fever, anorexia, or dyspnea, and more specific signs with neural, respiratory, cutaneous, or ocular involvement. Because of the wide range of clinical signs, the diagnosis in domestic and pet animals can be complicated. Hence, this review aims to provide a comprehensive analysis of some scarcely discussed aspects of toxoplasmosis, such as ocular and cutaneous manifestations, congenital infections, influence of T. gondii genotype on clinical toxoplasmosis, and recent findings regarding differential diagnosis. This review could be of special interest to clinicians and researchers.

Serological prevalence of toxoplasmosis and neosporosis in dogs diagnosed with suspected meningoencephalitis in the UK

OBJECTIVES

To assess the prevalence of antibodies to Toxoplasma gondii and Neospora caninum in a population of dogs with a diagnosis of suspected inflammatory meningoencephalitis.

MATERIALS AND METHODS

Medical records of three referral centres were reviewed from 2008 to 2016 to identify a cohort of dogs diagnosed and treated for suspected inflammatory meningoencephalitis after testing for evidence of exposure to these pathogens.

RESULTS

In our sample of 400 dogs the prevalence for exposure (IgG>1:50) to Toxoplasma gondii was 8/201 (3∙98%). Active infection (IgG titre >1:400 or/and an IgM titre >1:64 and/or positive PCR in CSF) was suspected in 1/400 (0∙25%). The prevalence for exposure [Indirect fluorescent antibody (IFA) titre >1:50] and active infection (IFA titres ≥⃒1:400 and/or positive PCR in CSF) with Neospora caninum were 14/201 (6∙96%) and 9/400 (2∙25%), respectively.

CLINICAL SIGNIFICANCE

In view of the low prevalence of protozoan infections, the risk associated with starting immunosuppressive medication in dogs with evidence of inflammatory meningitis or encephalitis in the UK appears low.

An update on Sarcocystis neurona infections in animals and equine protozoal myeloencephalitis (EPM)

Equine protozoal myeloencephalitis (EPM) is a serious disease of horses, and its management continues to be a challenge for veterinarians. The protozoan Sarcocystis neurona is most commonly associated with EPM. S. neurona has emerged as a common cause of mortality in marine mammals, especially sea otters (Enhydra lutris). EPM-like illness has also been recorded in several other mammals, including domestic dogs and cats. This paper updates S. neurona and EPM information from the last 15 years on the advances regarding life cycle, molecular biology, epidemiology, clinical signs, diagnosis, treatment and control.