Canine neosporosis: perspectives on pathogenesis and management

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.

Molecular and serological prevalence rates of Neospora caninum infection in dogs from Jordan

Neosporosis is a proven disease of farm animals and dogs caused by Neospora caninum. This cross-sectional study investigates N. caninum prevalence and seroprevalence among 268 dogs. Nc5 gene PCR was carried out on dog faeces and confirmed by sequencing. Seroprevalence was detected using an indirect fluorescent antibody test (IFAT). Three age groups, gender, locality (Amman, Irbid, and Zarqa Governorates), dog type (stray, pet, and breeding), place of living (indoor/outdoor), food type (raw/cooked), having diarrhoea, having abortion in the area, and having animals nearby were tested as independent variables for associations with positivity to N. caninum using univariate and multivariable logistic regression analyses. The true prevalence of N. caninum was 34.3% (95% CI 28.4, 40.5) using the Nc5-PCR test. The true seroprevalence rate of N. caninum among dogs in Jordan was 47.9% (95% CI 41.4, 54.5) using IFAT. The sequenced isolates of Nc5-PCR products (n = 85) matched three N. caninum strains, namely, NcHareGre (n = 70, 82.4%, 95% CI 72.6-89), NC MS2 (n = 14, 16.5%, 95% CI 9.3-26.1), and L218 (n = 1, 1.2%, 95% CI 0.03-6.4). The three strains were isolated previously from three different countries and continents. N. caninum shedding is associated with abortion among dogs and animals in the area (odds ratio = 3.6). In Amman and Zarqa, living indoors reduced seroprevalence at 0.45, 0.24, and 0.02 odds ratios, respectively. Jordan shares three molecular N. caninum strains with three different countries and continents.

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.

Systematic Review and Meta-analysis of Role of Felids as Intermediate Hosts in the Life Cycle of Neospora caninum Based on Serological Data

PURPOSE

Neosporosis is an important widespread parasitic infection caused by N. caninum. It infects a wide range of warm-blooded animals as intermediate hosts and dogs as the definitive host. Nevertheless, there are a number of questions regarding the life cycle and epidemiological aspects of N. caninum. Also, the role of felids (domestic and non-domestic) in the life cycle of N. caninum has been little described. Therefore, this study was conducted to evaluate the global prevalence of N. caninum in domestic and wild felids.

METHODS

PubMed, Scopus, Google Scholar, Web of Science, and ScienceDirect databases were searched for articles published on the prevalence of N. caninum in felids until Aprill 2, 2022 and the reference lists of retrieved articles were screened. A random-effects meta-analysis model was used to estimate the pooled prevalence and 95% confidence interval. Heterogeneity among studies was evaluated using Cochran's Q and the I² statistic.

RESULTS

After exclusion of irrelevant articles and duplication removal, 30 studies were eligible for quantitative analysis including 20 studies on domestic cats and 10 studies on wild felids. The overall prevalence of neosporosis infection in cats was 15% (95% CI 10-21%) that was significantly higher in wild felids (26%, 95% CI 13-38%) than in domestic cats (11%, 95% CI 6-16%) (P = 0.03). There was no significant difference in pooled prevalence between male and female domestic cats (P = 0.75). Regarding continent, the lowest prevalence of neosporosis infection was in Asia (9%, 95% CI 1-20%) and the highest was in North America (43.6%, 95% CI 33.9-53.2%) and Africa (18%, 95% CI 9-46%). Higher prevalence was obtained when using the NAT with 22% (95% CI 7-37%), compared to the IFAT (17%, 95% CI 9-24%) and ELISA (6%, 95% CI 2-9%) (P = 0.01).

CONCLUSION

The findings highlighted the importance of felids as potential intermediate hosts of neosporosis despite the fact that the source of the parasite for these animals was unknown. Further studies should be performed to investigate the role of this top predator (felids) in maintaining both domestic and sylvatic cycles of Neospora caninum.

Neospora spp. Seroprevalence and Risk Factors for Seropositivity in Apparently Healthy Horses and Pregnant Mares

Simple Summary

Neosporosis, caused by the parasite Neospora species, is recognized as one of the major causes of abortion in cattle worldwide causing large economic losses. Over the past few years, Neospora infection and parasite transmission from the mare to the fetus has been documented in horses and was associated with reproduction failure. In the present study, we investigated parasite prevalence and associated risk factors in the general equine population and in a group of pregnant mares during pregnancy and after parturition. Our findings revealed high exposure of horses to Neospora spp. parasites, with significantly higher prevalence in pregnant mares.

Abstract

Equine Neospora infection has been linked to neurological disorders and infertility in horses. This study looked into the risk factors for infection and the exposure to Neospora spp. in horses. The study was performed in two independent populations in Israel. The first consisted of apparently healthy horses, and the second consisted of mares examined during pregnancy and after parturition. Sera samples collected from horses and mares were tested for Neospora exposure by the indirect fluorescent antibody test (IFAT). The study revealed seroprevalence of 24% in apparently healthy horses and 66.4% and 48.6% in mares during gestation and after parturition, respectively. Among the investigated risk factors, older age (p = 0.026) and housing in both stalls and paddocks (p = 0.033) in apparently healthy horses, and Arabian breeds (p = 0.005) in pregnant mares, were found to be significantly associated with Neospora spp. seropositivity in univariable, but not multivariable, statistical analysis. This study revealed high exposure of equines to Neospora parasites, especially mares. Horse farm management, in combination with active surveillance, including serological testing and follow up, could help reduce the spread of the parasite among horses in endemic areas.

Atmospheric-pressure scanning microprobe matrix-assisted laser desorption/ionization mass spectrometry imaging of Neospora caninum-infected cell monolayers

Neospora caninum is an obligate intracellular protozoan parasite of the phylum Alveolata (subphylum Apicomplexa) which has not been studied extensively in a biochemical context. N. caninum is a primary cause of reproductive disorders causing mummification and abortion not only in cattle but also in other small ruminant species resulting in a substantial economic impact on the livestock industry. In canids, which are the final hosts of N. caninum, clinical disease includes neuromuscular symptoms, ataxia, and ascending paralysis. Fatal outcomes of neosporosis have also been reported depending on the host species, age and immune status, however, its zoonotic potential is still uncertain. Therefore, N. caninum should be thoroughly investigated. Matrix-assisted laser desorption/ionisation (MALDI) mass spectrometry (MS) and MS imaging (MSI) were used, combined with high-performance liquid chromatography (HPLC) to investigate these intracellular parasites. The aim of this study was to identify molecular biomarkers for N. caninum tachyzoite-infected host cells and to further clarify their functions. By atmospheric-pressure scanning microprobe MALDI MS(I), sections of N. caninum-infected and non-infected host cell pellets were examined in order to determine potential markers. In vivo, N. caninum infects different types of nucleated cells, such as endothelial cells which represent a highly immunoreactive cell type. Therefore, primary bovine umbilical vein endothelial cells were here used as a suitable infection system. For comparison, the permanent MARC-145 cell line was used as an additional, simplified in vitro cell culture model. HPLC-tandem MS (HPLC-MS/MS) experiments combined with database search were employed for structural verification of markers. The statistically relevant biomarkers found by MS and identified by HPLC-MS/MS measurements were partly also found in infected monolayers. Marker signals were imaged in cell layers of N. caninum-infected and non-infected host cells at 5 µm lateral resolution.

Neospora caninum, a cause of abortion in donkeys (Equus asinus) in Iran

Neospora caninum is an Apicomplexan parasite that can cause enormous economic losses due to abortions in cattle. The present study investigated the role of Neospora spp. infection in equine abortion in Iranian donkeys using molecular and phylogenetic analyses. Twenty-nine-aborted fetuses and 29 blood samples from their dams were collected from six different regions in the West and Northwest of Iran. They were tested for N. caninum by PCR at the Nc5 locus, followed by sequencing of five of the PCR products. The overall molecular prevalence was 34.5% in blood samples and the prevalence by DNA detection in the aborted fetuses was 13.8%. Evidence of transplacental transmission from positive jennies to their fetuses was detected in 40% of aborting jennies. Comparison of the five partial Nc5 sequences (227 bp length) exhibited 98-100% similarity with N. caninum GenBank sequences. This is the first molecular study and genetic characterization of N. caninum in Iranian donkeys suggests that N. caninum may be a significant cause of abortion in donkeys.

Immune Protective Evaluation Elicited by DNA Vaccination With Neospora caninum Dense Granules Proteins in Mice

Neospora caninum, an obligate intracellular protozoan, is the major cause for neosporosis and brings serious economic losses to cattle breeding industries worldwide. After invasion, dense granules proteins are abundantly secreted and being important components of parasitophorous vacuole and intravacuolar network where N. caninum survives and replicates. The aim of the present study was to evaluate the protective immunity induced by DNA vaccines with genes encoding dense granules proteins 1 (GRA1), GRA4, GRA9, GRA14, GRA17, and GRA23 against N. caninum tachyzoites in BALB/C mice. Eukaryotic expressing plasmids of pcNcGRAs were constructed and the mice were intramuscularly immunized with pcNcGRAs followed by challenging infection with lethal doses of N. caninum. Immune responses were evaluated through monitoring the levels of serum antibodies, measurement of lymphocyte proliferation, and secretion of cytokines. Immune protection assays were carried out through monitoring survival time, body weight, and parasite burden in the brains. Results showed that all the pcNcGRA DNA vaccines could trigger remarkably specific humoral and cellular responses, with higher levels of IgG and IgG2a antibodies as well as obviously increased secretion of Th1-type IFN-γ cytokines. The immune protective efficacy revealed that pcNcGRA4, pcNcGRA14, and pcNcGRA17 DNA vaccines could individually increase the survival rate to 50, 37.5, and 25% in comparison with 0% in the control group; prolong the survival time more than 20.88 ± 11.12, 18.88 ± 10.83, and 16.63 ± 10.66 days compared with the control group of 4 ± 1.31 days; and decrease parasite burden in the brains to 297.63 ± 83.77, 471.5 ± 110.74, and 592.13 ± 102.2 parasites/100 ng comparing with 1221.36 ± 269.59 parasites/100 ng in the control group. These findings indicated that NcGRA4, NcGRA14, and NcGRA17 are potential vaccine candidates; NcGRA4 displayed better performance in immune protective efficacy and could be further combined with other advantageous antigens applied to the development of safe and effective DNA vaccines against N. caninum.

Disruption of Dense Granular Protein 2 (GRA2) Decreases the Virulence of Neospora caninum

Neospora caninum causes abortions in cattle and nervous system dysfunction in dogs. Dense granular proteins (GRAs) play important roles in virulence; however, studies on NcGRA functions are limited. In the present study, multiple methods, including site-directed mutagenesis; CRISPR/Cas9 gene editing; Western blotting; quantitative polymerase chain reaction; confocal microscopy; plaque, invasion, egress, and replication assays; animal assays of survival rate and parasite burden; and hematoxylin-eosin staining, were used to characterize the NcGRA2 protein, construct an NcGRA2 gene disruption (ΔNcGRA2) strain, and explore its virulence in vivo and vitro. The results showed that NcGRA2 shared 31.31% homology with TgGRA2 and was colocalized with NcGRA6 at the posterior end of tachyzoites and the intravacuolar network of parasitophorous vacuoles (PVs). Cell fractionation analysis showed that NcGRA2 behaved as a transmembrane and membrane-coupled protein. The ΔNcGRA2 strain was constructed by coelectroporation of the NcGRA2-targeting CRISPR plasmid (pNc-SAG1-Cas9:U6-SgGRA2) and DHFR-TS DNA donor and verified at the protein, genome, and transcriptional levels and by immunofluorescence localization analysis. The in vitro virulence results showed that the ΔNcGRA2 strain displayed smaller plaques, similar invasion and egress abilities, and slower intracellular growth. The in vivo virulence results showed a prolonged survival time, lower parasite burden, and mild histopathological changes. Overall, the present study indicates that NcGRA2, as a dense granular protein, forms the intravacuolar network structure of PVs and weakens N. caninum virulence by slowing proliferation. These data highlight the roles of NcGRA2 and provide a foundation for research on other protein functions in N. caninum.

Effects of Neospora caninum on reproductive parameters in dairy cows from a closed herd in Brazil

Dairy production and cattle reproductive parameters exhibit a strong relationship, which can be disrupted by infectious agents, such as Neospora caninum, that affect the reproductive tract of these animals. Neosporosis is a major cause of abortion in cattle worldwide and is responsible for substantial economic losses. We evaluated the impact of N. caninum infection on the reproductive parameters of 434 Holstein dairy cows from a herd in Brazil that had been closed for 4 years through the assessment of serological testing and reproductive parameters. Dairy cows older than 24 months and that required at least 2.2 inseminations to become pregnant had a higher frequency of seropositive results. Analysis of the medians of positive and negative cows revealed that seropositive cows tended to require more insemination efforts to achieve pregnancy and showed a 2-month increase in age at first calving. According to the reproductive parameters, the correlation coefficient was higher in seronegative animals, while no such correlation was detected in seropositive cows. Thus, we concluded that N. caninum negatively affects the reproductive parameters of dairy cows kept in a closed herd.

Effects of Dense Granular Protein 6 (GRA6) Disruption on Neospora caninum Virulence

Neospora caninum (N. caninum) is a major cause of abortions in cattle. During its invasion of host cells, a parasitophorous vacuole (PV) is formed, accompanied by an intravacuolar network (IVN). The IVN takes part in parasite ingesting of nutrients from hosts. The dense granular proteins of N. caninum (NcGRAs) play a key role in forming the PV and the IVN, which may influence virulence during N. caninum invasion. The present study aimed to explore the biological function of NcGRA6 in N. caninum by disrupting the NcGRA6 gene in the Nc-1 strain. We successfully constructed an NcGRA6-targeting CRISPR plasmid (pNc-SAG1-Cas9:U6-SgGRA6) and amplified the DHFR-TS DNA donor. The NcGRA6 knockout mutation (ΔNcGRA6) was generated by co-electroporation of the pNc-SAG1::CAS9-U6::sgGRA6 plasmid and the DHFR-TS DNA donor into the Nc-1 strain, which was then cultured under pyrimethamine selection pressure. The ΔNcGRA6 mutation was further verified by identification of NcGRA6 gene disruption using PCR, measurement of NcGRA6 gene transcription levels using qPCR, assessment of NcGRA6 protein expression levels using western blotting, and observation of NcGRA6 protein location using immunofluorescence and immunoelectron microscopy. The results of in vitro virulence assays, including plaque, invasion, egress, and replication assays, showed that the ΔNcGRA6 strain had smaller plaques, similar invasion and egress ability, and slower intracellular replication ability than the Nc-1 strain. The results of in vivo virulence assays showed that the ΔNcGRA6 strain exhibited reduced virulence and improved survival ability in mice compared with the Nc-1 strain. The parasite burden in ΔNcGRA6 strain-infected mouse tissues, including the heart, brain, liver, spleen, lung, and kidney, was significantly reduced compared with that in mice infected with the Nc-1 strain. These data suggest that we successfully constructed a ΔNcGRA6 strain and verify that NcGRA6 is a critical virulence factor. NcGRA6 gene disruption can slow down N. caninum proliferation and lower the pathogenicity to hosts. Our findings provide a foundation for future research on other targeted N. caninum protein functions and may help in exploring the interaction mechanisms between parasites and hosts.

Disseminated Neospora caninum infection in a dog with severe colitis

A 12-y-old spayed female Schipperke dog with a previous diagnosis of inflammatory bowel disease was presented with a 2-mo history of severe colitis. The patient's condition progressed to hepatopathy, pneumonia, and dermatitis following management with prednisolone and dexamethasone sodium phosphate. Colonic biopsies identified severe necrosuppurative colitis with free and intracellular parasitic zoites. Postmortem examination confirmed extensive chronic-active ulcerative colitis, severe acute necrotizing hepatitis and splenitis, interstitial pneumonia, ulcerative dermatitis, myelitis (bone marrow), and mild meningoencephalitis with variable numbers of intracellular and extracellular protozoal zoites. PCR on samples of fresh colon was positive for Neospora caninum. Immunohistochemistry identified N. caninum tachyzoites in sections of colon, and a single tissue cyst in sections of brain. Administration of immunosuppressive drugs may have allowed systemic dissemination of Neospora from the intestinal tract.

Immediate Interferon Gamma Induction Determines Murine Host Compatibility Differences between Toxoplasma gondii and Neospora caninum

Rodents are critical for the transmission of Toxoplasma gondii to the definitive feline host via predation, and this relationship has been extensively studied as a model for immune responses to parasites. Neospora caninum is a closely related coccidian parasite of ruminants and canines but is not naturally transmitted by rodents. We compared mouse innate immune responses to N. caninum and T. gondii and found marked differences in cytokine levels and parasite growth kinetics during the first 24 h postinfection (hpi). N. caninum-infected mice produced significantly higher levels of interleukin-12 (IL-12) and interferon gamma (IFN-γ) by as early as 4 hpi, but the level of IFN-γ was significantly lower or undetectable in T. gondii-infected mice during the first 24 hpi. "Immediate" IFN-γ and IL-12p40 production was not detected in MyD88-/- mice. However, unlike IL-12p40-/- and IFN-γ-/- mice, MyD88-/- mice survived N. caninum infections at the dose used in this study. Serial measures of parasite burden showed that MyD88-/- mice were more susceptible to N. caninum infections than wild-type (WT) mice, and control of parasite burdens correlated with a pulse of serum IFN-γ at 3 to 4 days postinfection in the absence of detectable IL-12. Immediate IFN-γ was partially dependent on the T. gondii mouse profilin receptor Toll-like receptor 11 (TLR11), but the ectopic expression of N. caninum profilin in T. gondii had no impact on early IFN-γ production or parasite proliferation. Our data indicate that T. gondii is capable of evading host detection during the first hours after infection, while N. caninum is not, and this is likely due to the early MyD88-dependent recognition of ligands other than profilin.

Neospora caninum, A potential cause of reproductive failure in dairy cows from Northern Greece

Neospora caninum infection has been reported in a large number of intermediate hosts, such as ruminants, rabbits, mice, etc. but neosporosis has emerged as a serious disease in cattle and dogs worldwide. Abortions and other infertility issues have been reported in the infected cows, leading to great economic losses in farmers. The aim of our study was to assess N. caninum seroprevalence in dairy cattle from Northern Greece (region of Xanthi) by using the indirect fluorescent antibody technique. Blood samples were collected from 875 Holstein – Friesian dairy cows and tested for Neospora caninum antibodies. Among the cows that were studied, 184 (21.03%) were positive for N. caninum antibodies and concurrently their farms had a known previous history of infertility problems, such as abortions, increased number of artificial inseminations needed for conception, increased rate of returning to estrus and retention of fetal membranes.

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Neosporis is a common parasitosis in dairy cows.

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The number of abortions was significantly higher in seropositive cows.

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In seropositive cows the number of artificial inseminations was increased.

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The birth interval was much more longer in the N. caninum seropositive cows.

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Significant economic loss was observed in the infected farms.

Systemic disseminated Neospora caninum infection with cutaneous lesions as the initial clinical presentation in a dog

This report describes a disseminated Neospora caninum infection with cutaneous involvement as the primary presenting clinical sign, in an apparently immunocompetent 7-year-old, spayed female boxer dog. The dog had an 8-day history of progressive lethargy associated with the appearance of multiple cutaneous and ulcerated masses, followed by an acute deterioration of her clinical status. Blood analysis revealed thrombocytopenia, increased liver enzyme activity, and partial thromboplastin time. Disseminated intravascular coagulation was suspected. Tachyzoites were identified on cutaneous cytology and species was determined by polymerase chain reaction (PCR) assays on blood and cerebrospinal fluid. The post-mortem evaluation revealed involvement of the neurological system, liver, lung, and skin.

Raw diets for dogs and cats: a review, with particular reference to microbiological hazards

There is a recent trend to feed pet dogs and cats in Britain and other developed countries on raw meat and animal by-products using either commercial preparations or home recipes. This shift from heat-treated processed food has been driven by perceived health benefits to pets and a suspicion of industrially produced pet food. The diets of wild-living related species have been used as a rationale for raw feeding, but differences in biology and lifestyle impose limitations on such comparisons. Formal evidence does exist for claims by raw-feeding proponents of an altered intestinal microbiome and (subjectively) improved stool quality. However, there is currently neither robust evidence nor identified plausible mechanisms for many of the wide range of other claimed benefits. There are documented risks associated with raw feeding, principally malnutrition (inexpert formulation and testing of diets) and infection affecting pets and/or household members. Surveys in Europe and North America have consistently found Salmonella species in a proportion of samples, typically of fresh-frozen commercial diets. Another emerging issue concerns the risk of introducing antimicrobial-resistant bacteria. Raw pet food commonly exceeds hygiene thresholds for counts of Enterobacteriaceae. These bacteria often encode resistance to critically important antibiotics such as extended-spectrum cephalosporins, and raw-fed pets create an elevated risk of shedding such resistant bacteria. Other infectious organisms that may be of concern include Listeria, shiga toxigenic E scherichia coli , parasites such as Toxoplasma gondii and exotic agents such as the zoonotic livestock pathogen Brucella suis, recently identified in European Union and UK raw pet meat imported from Argentina.

Seroepidemiological survey of Neospora caninum and its risk factors in farm dogs in Nakuru district, Kenya

Aim:

The objective of this study was to determine the seroprevalence of Neospora caninum (NC) and its risk factors in farm dogs in Kenya.

Materials and Methods:

As part of a longitudinal study on dairy cattle abortion in 2010 in Kenya, serum samples were collected from 84 dogs in 53 randomly selected dairy cattle farms to determine the seroprevalence and risk factors of seropositivity for NC.

Results:

15 (17.9%) of the dogs were seropositive to NC antibodies, and at least one seropositive dog was found in 12 (22.6%) of the 53 farms. The final multivariable logistic regression model identified free-roaming as the only factor significantly associated with seropositivity (odds ratio=4.48; p=0.03).

Conclusion:

The findings of this study indicate that canine neosporosis does exist in Kenya and that farmers should restrict their dogs from roaming to reduce the risk of their dogs becoming a reservoir for NC. More studies need to be carried out to determine the reproductive effects of NC on dairy cattle in Kenya.