The prevalence of Neospora caninum and co-infection with Toxoplasma gondii by PCR analysis in naturally occurring mammal populations

Serological and molecular detection of Toxoplasma gondii and Neospora caninum in free-ranging rats from Nagpur, India

Toxoplasma gondii and Neospora caninum are cyst-forming coccidian parasites that infect both wild and domestic non-felids as intermediate hosts, with rodents serving as important reservoir hosts during their life cycles. This study was aimed at investigating T. gondii and N. caninum infections and identifying factors favouring T. gondii infection in free-ranging rats from India. A total of 181 rodents were trap-captured, and blood and brain samples were subsequently collected for serological and molecular examination of T. gondii and N. caninum. Antibodies against T. gondii and N. caninum were detected by MAT/NAT and IFAT in 13.8% (25/181) and 1.65% (3/181) of rodents, respectively. All three N. caninum samples positive by NAT/IFAT were also positive for ELISA, while for T. gondii, 19 of 25 MAT/IFAT positive samples were also positive for ELISA. The antibody titers (MAT/NAT/IFAT) of rodents seropositive for T. gondii ranged from 25 to 400, while those of rats seropositive for N. caninum ranged from 25 to 100. Also, using PCR, DNA from T. gondii (B1 gene) and N. caninum (NC5 gene) was found in 2.76% (5/181) of brain samples and 0.55% (1/181) of brain samples. All PCR positive samples were also seropositive. No mixed infections were observed in the serological and molecular detections. A Chi-square analysis revealed that older rats and rats living in urban areas are significantly associated with T. gondii infection; however, rodent species, gender, location, habitat types, and seasonality were statistically nonsignificant. Overall, this study demonstrated that T. gondii was widely distributed while N. caninum was less prevalent among free-ranging rats in the studied area.

Molecular detection and phylogenic characterization of Neospora caninum in naturally infected sheep in Alborz and Qazvin provinces, the north of the central region of Iran

Neospora caninum is a protozoan coccidian parasite that can act as a cause of abortion in sheep. The aim of this study was to investigate the presence of this parasitic agent and its role in causing abortion in sheep of Iran. Between June 2019 and February 2022, 100 samples [brain (n = 39), placenta (n = 8), embryonic membrane (n = 7), cotyledon (n = 7), umbilical cord (n = 2), homogenate mixture of tissues (heart, liver, spleen and digestive track) (n = 37)] that were collected following the necropsies of 39 aborted ovine fetuses from different parts of the Alborz and Qazvin provinces, the north of the central region of Iran were employed for DNA extraction. Nc-5 was selected as the target gene sequence for amplification of DNA by using four pairs of primers in two semi-nested PCR. Samples considered positive for the presence of the NC-5 gene were examined to further confirm the presence of the ITS1 gene. Sequence of NC-5 gene was detected from the 27 tissue samples of 23 aborted ovine fetuses. The ITS1 gene sequence was detected in all of the 27 tissue samples that were positive for the NC-5 gene analysis. Brain tissue was the most studied tissue, and the highest number of positive cases was observed in this tissue. The present study updated the situation of ovine neosporosis in the central region of Iran and confirmed the presence of the N. caninum among sheep flocks' abortion.

Toxoplasma gondii in small mammals in Romania: the influence of host, season and sampling location

BACKGROUND

Toxoplasma gondii is a protozoan parasite that infects a large spectrum of warm-blooded animals, including humans. Small rodents and insectivores play an important role in the epidemiology of T. gondii and may serve as a source of infection for both, domestic and wild definitive felid hosts. Factors influencing the occurrence of T. gondii in wild small mammals are unknown, despite the fact that many intermediate host species are identified. We have used small mammals (Rodentia and Lipotyphla) captured over two years in various habitats, both in urbanised and in natural landscapes. We assessed the importance of land-use, season and host ecology on T. gondii infection.

RESULTS

We examined 471 individuals belonging to 20 small mammal species, collected at 63 locations spread over wide altitude, habitat and land-use ranges from Romania. Heart tissue samples were individually analysed by PCR targeting the 529 bp repetitive DNA fragment of T. gondii. The overall prevalence of infection was 7.3%, with nine species of rodents and two species of shrews being found to carry T. gondii DNA. Five species showed high frequency of infection, with the highest prevalence found in Myodes glareolus (35.5%), followed by Spermophilus citellus (33.3%), Sorex minutus (23.1%), S. araneus (21.7%) and Micromys minutus (11.1%). Adults seemed more often infected than young, however when controlling for season, the difference was not significant, as in spring both adults and young showed higher infection rates, but more adults were sampled. Contrary to our expectations, urban/rural areas (with their implicit high density of domestic feline presence) had no effect on infection prevalence. In addition, neither habitat, nor land-use at sampling sites was important as only geographical location and host species were contributing factors to the infection risk.

CONCLUSIONS

High prevalence of T. gondii infection showed a highly localised, patchy occurrence, with long living and higher mobility host species being the most common carriers, especially during autumn.

Global prevalence of Neospora caninum in rodents: A systematic review and meta-analysis

BACKGROUND

Neosporosis has been considered a cause of abortion in dairy and beef cattle worldwide. Rodents are reservoir hosts for several infectious diseases. It is necessary to determine the prevalence of Neospora caninum in rodents to improve the current understanding of the transmission dynamics of Neospora as well as its life cycle and risk of transmission to livestock. Therefore, the objective of the present study was to estimate the pooled global prevalence of N. caninum in different rodent species.

METHODS

Published studies on the prevalence of N. caninum in different rodent species were searched in the MEDLINE/PubMed, ScienceDirect, Web of Science, Scopus and Google Scholar and the reference lists of the retrieved articles until July 30, 2022. The eligible studies were selected using inclusion and exclusion criteria. The extracted data were verified and analysed using the random-effect meta-analysis.

RESULT

For this meta-analysis, a total of 4372 rodents from 26 eligible studies were included. The global prevalence of N. caninum in rodents was estimated at 5% (95% CI 2%-9%), with the highest prevalence in Asia (12%; 95% CI 6%-24%) and lowest prevalence in America (3%; 95% CI 1%-14%) and Europe (3%; 95% CI 1%-6%). N. caninum was more prevalent in females (4%; 95% CI 2%-9%) than in males (3%; 95% CI 1%-11%). The most common diagnostic test was polymerase chain reaction (PCR) (21 studies). The pooled prevalence of N. caninum in rodents based on the diagnostic method was as follows: immunohistochemistry: 11% (95% CI 6%-20%), NAT: 5% (95% CI 4%-7%), IFAT: 5% (95% CI 2%-13%) and PCR: 3% (95% CI 1%-9%).

CONCLUSION

The results of this study showed a relatively low but widespread prevalence of N. caninum infection in rodents.

Seroprevalence and risk factors of Toxoplasma gondii and Neospora caninum infection in black goats in Yunnan Province, Southwestern China

Toxoplasma gondii and Neospora caninum are two obligate intracellular protozoan parasites that can cause reproductive failure and production losses. To date, there is no data of T. gondii and N. caninum seroprevalence in black goats in Yunnan Province, southwestern China. In the present study, a total of 734 serum samples were collected from black goats in four different counties of Yunnan Province. 734 and 590 serum samples were examined for antibodies against T. gondii and N. caninum by using MAT and indirect ELISA, respectively. A total of 123 and 76 samples were T. gondii-positive and N. caninum-positive, respectively. The overall seroprevalence of T. gondii in black goats was 16.76% (123/734, 95% CI: 14.06-19.46) with the titer ranged from 1:25 to 1:3200. The seroprevalence of N. caninum was 12.88% (76/590, 95% CI: 10.18-15.58). There was significant difference in seroprevalence of N. caninum in different regions (P < 0.01, χ² = 30.63) and age groups (P < 0.05, χ² = 11.85). Significant differences in seroprevalence of T. gondii were observed in different regions (P < 0.05, χ² = 9.21) and different gender groups (P < 0.01, χ² = 12.29). Results of seroprevalence of T. gondii and N. caninum indicated that T. gondii and N. caninum were prevalent parasites in black goats in Yunnan Province. This is the first report of seroprevalence of T. gondii and N. caninum in black goats in Yunnan Province. The results of this study indicated that some measures should be taken to control these two parasites and to reduce economic losses to the livestock industry in Yunnan Province.

Ovine Neosporosis: The Current Global Situation

Simple Summary

This review summarizes the current global situation of Neospora caninum infection in sheep by referring to all of the available descriptions of natural ovine neosporosis to date, focusing on epidemiology, clinical signs, lesions, and diagnosis. The data suggest that ovine neosporosis is more prevalent than currently thought, that it has increased in the last few decades, and that it should now be considered in the differential diagnosis when investigating abortion in sheep.

Abstract

In the past 20 years, Neospora caninum infection in sheep has been reported in at least 31 countries worldwide from all sheep-rearing continents (Europe, Asia, the Americas, Africa, and Oceania), and its role as an abortifacient agent is becoming more evident. Most studies of ovine neosporosis have focused on its epidemiology, based primarily on serological analysis, with only a few studies investigating the actual presence of the parasite by PCR and/or IHC. Individual seroprevalence rates were highly variable between countries, and even between regions within the same country, ranging from 0.0% to 67.4% positive. Furthermore, most of the studies were not directly comparable due to differences in experimental designs, sample sizes, husbandry systems, ecological factors, and serological tests (e.g., IFAT, ELISA, MAT, Western blot). The latter, along with the scarcity of studies on the relevance of N. caninum as an abortifacient agent, may bias the perception of the importance of this disease. This review summarizes the situation of N. caninum infection in sheep using all available published studies describing natural ovine neosporosis. The epidemiology shows that ovine neosporosis is found worldwide, and it poses a relevant risk to the sustainability of sheep flocks.

The Global Prevalence of Neospora caninum Infection in Sheep and Goats That Had an Abortion and Aborted Fetuses: A Systematic Review and Meta-Analysis

Neospora caninum (N. caninum) can be a potential factor causing a significant rate of miscarriages in small ruminants (sheep and goats) worldwide. Therefore, the present study aimed to determine the global status of N. caninum in sheep and goats that had an abortion and aborted fetuses. Five English databases (PubMed, ScienceDirect, Web of Science, Scopus, and ProQuest) were searched for relevant scientific articles published from their inception until November 4, 2021. Finally, 21 studies conducted on sheep (1,671 aborted fetuses and 935 abortive sheep) and 10 studies on goats (130 aborted fetuses and 80 abortive goats) were included for the final meta-analysis. A random-effects meta-analysis model was used to estimate the pooled prevalence with 95% confidence intervals (CIs). Moreover, sensitivity analysis, publication bias test, and quality assessment were performed in this study. The pooled prevalence of N. caninum in aborted fetuses of sheep and goats globally was estimated to be 15% (95% CI: 9-21%) and 7% (95% CI: 2-12%) using molecular methods. Besides, the seroprevalence of N. caninum was estimated to be 17% for aborted fetuses of sheep. The overall prevalence rate of N. caninum infection in sheep that had an abortion was 3%. The present results show a relatively high prevalence of N. caninum infection in sheep that had an abortion and aborted fetuses compared to goats. Therefore, further studies using different diagnostic techniques to more accurately estimate the rate of infection in sheep and goats may help provide adequate control measures and strategies to reduce the rate of abortion in sheep and goats and reduce economic damage to the livestock industry. This study was registered at the International Prospective Register of Systematic Reviews (PROSPERO; code: CRD42020216694).

Neospora caninum and Toxoplasma gondii as causes of reproductive losses in commercial sheep flocks from Argentina

The aim of this study is to provide preliminary data about the occurrence of Neospora caninum- and Toxoplasma gondii-related abortions and perinatal deaths in sheep from Argentina. Thirty ovine aborted foetuses and 33 perinatal deaths were submitted to the Veterinary Diagnostic Service at INTA EEA Balcarce (Argentina) during 2017–2019. A complete necropsy was performed on all specimens submitted, and foetal and placental tissues were examined. Foetal cavity fluids were collected for assessment of antibodies to N. caninum and T. gondii by indirect fluorescent antibody technique (IFAT). Placental and foetal tissue samples were collected for DNA extraction and histopathological analysis. The differential diagnosis with other causes of abortion was carried out. Of the sampled specimens, 20.63% (13/63) displayed evidence for N. caninum infection by IFAT and PCR, and in 61.5% (8/13) of the positive specimens the parasite was confirmed as the cause of abortion/perinatal death based on the presence of compatible histological lesions and/or positive immunohistochemistry test, positive PCR and/or positive IFAT, and no other infectious agents diagnosed. In contrast, T. gondii infection was confirmed in 9.52% (6/63) of the analysed specimens, but only in 2 lambs T. gondii was determined as the death cause. Neosporacaninum and T. gondii co-infections were confirmed in 4 analysed specimens (2 aborted foetuses and 2 perinatal deaths). These results demonstrated that N. caninum is efficiently transmitted and a frequent cause of ovine reproductive failure in the commercial analysed flocks compared with T. gondii. Despite T. gondii congenital infection was detected in some specimens (6/63), it was confirmed as the cause of death in only two of them. Thus, and considering the limited availability of confirmed samples, we could not determine whether toxoplasmosis is a major problem in Argentinian sheep flocks or not. More studies on a greater number of specimens from different ovine production systems under different management conditions are necessary to assess the real impact of neosporosis and toxoplasmosis in Argentina.

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Neospora caninum congenital infection was found in 13 of the 63 analysed specimens.

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In 8 of these 13 cases, N. caninum was confirmed as the cause of abortion/perinatal death.

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Toxoplasma gondii was determined as the perinatal death cause in 2 lambs.

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Co-infections with N. caninum + T. gondii were only confirmed in 4 analysed specimens.

Investigation of Toxoplasma gondii and Neospora caninum as cause of ovine abortion in affected flocks of Urmia, northwest of Iran

Toxoplasma gondii and Neospora caninum, two obligatory intracellular protozoan parasites, are important causes of neonatal mortality and abortion in farmed ruminants worldwide. Previously, protozoan abortions in small ruminants were attributed to T. gondii, but the role of N. caninum in these abortions was uncertain. The aim of this study was to investigate the role of T. gondii and N. caninum in ovine abortion in Urmia, northwest of Iran using a molecular method. Overall, 130 placenta and brain samples of aborted ovine foetuses were collected. Extracted DNA from placenta and CNS tissues of the aborted foetuses were analysed using PCR with primers specific for T. gondii and N. cani­num. The association of the frequency of T. gondii and N. caninum infection of aborted foetuses with age and breed in flocks was also studied. The results showed that out of the 130 examined ovine foetuses, 5.3 and 2.3 % were PCR-positive for T. gondii and N. caninum DNA, respectively. In this study, no significant differences were recorded relating to Toxoplasma and Neospora infection in different age groups in flocks and among sheep breeds included in the present study (P>0.05). The results of this study proved the importance of T. gondii and N. caninum as reasons of abortion in the studied area.

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.

Molecular identification of Neospora caninum and co-infection with Toxoplasma gondii in genital apparatus of naturally infected cows in North Tunisia

The aim of this study was to estimate the molecular prevalence of Toxoplasma gondii, Neospora caninum and the co-infection by both Apicomplexan parasites in uterus tissues of cows. PCR was used to detect T. gondii and N. caninum DNA in uterus from 140 uteri of slaughtered cows in the regional slaughterhouse of Béja (Northwest Tunisia). Positive PCR products were sequenced and used for the phylogenetic analysis. The overall molecular prevalence of T. gondii and N. caninum in cows' uterus was 5 and 15.57%, respectively. Co-infection prevalence by the two parasites was estimated to be 2.85%. Risk factors including the age categories significantly affected the molecular prevalence of T. gondii and N. caninum in cows' uterus. The highest molecular prevalence of T. gondii (11.5 ± 3.1) and N. caninum (21.1 ± 11.1; p = 0.038) was observed in cows aged of more than 8 years. There were no differences depicted according to cow's breeds and localities. Comparison of the partial sequences of the ITS1 gene revealed 100% similarity among our N. caninum sequence (MW136256) and those deposited in GenBank. The T. gondii sequence described in this study (MW260335) was 99.4-100% homologous to T. gondii sequences published in the GenBank.To the best of our knowledge, this is the first molecular evidence of N. caninum and T. gondii co-infection in naturally infected cows in North Africa. This information is pertinent in designing control programmes that would reduce economic losses in the livestock industry.

Molecular Identification of Neospora caninum Infection in Aborted Fetuses of Sheep, Cattle, and Goats in Mazandaran Province, Northern Iran

Background:

We aimed to identify Neospora caninum DNA in the brain samples of aborted fetuses of cattle, goats, and sheep in Mazandaran, northern Iran, using PCR.

Methods:

In total, 133 aborted fetuses (51 sheep, 78 cattle, and 4 goats) were randomly collected from different stages of gestation in various regions of Mazandaran, Iran, from Mar 2016 to May 2017. The DNA was extracted from all the brain samples using phenol chloroform isoamyl alcohol instructions. The Nc-5 gene was used for the detection of N. caninum DNA by nested-PCR assay.

Results:

The detection of N. caninum DNA was confirmed by the observation of a 227 bp band in 24 samples of 133 aborted fetuses (18.1%). The highest prevalence rate of N. caninum was detected in the cattle (20.5%) followed by the sheep (15.6%); however, no positive cases were reported in the goats. The highest and lowest prevalence rates of the infection were reported as 23.8% and 8.6% in Qaemshahr, and Behshahr, respectively. The prevalence rate of infection (32%) in the early gestational period was higher than those in the middle (15%) and late (3.8%) gestational periods.

Conclusion:

The obtained data of the present study indicated that N. caninum infection may partly be responsible for abortion and economic loss in livestock farming in Mazandaran Province.

Neospora caninum in free-range chickens (Gallus gallus domesticus) from southern Brazil

Neospora caninum is an obligate intracellular parasite that can infect many domestic and wild animals, including birds. These animals are important sources for monitoring of environmental contamination, as they could become infected through sporulated oocysts; however, the real role of birds in the biological cycle of N. caninum remains uncertain. This study aimed to determine the prevalence of anti-N. caninum antibodies, evaluate associated factors, detect the parasite by molecular testing of free-range chickens from Brazil, and evaluate different techniques for its serological diagnosis. Blood samples of 366 chickens from 25 farms were collected for serological assays. The indirect fluorescent antibody test (IFAT) and the indirect enzyme-linked immunosorbent assay (ELISA) were used to detect anti-N. caninum antibodies. Chickens that tested seropositive by IFAT had their brain tissues and a pool of organs (heart, lung, and liver) submitted to PCR for molecular detection of the parasite. Out of 366 chickens, 65 (17.8%) and 163 (44.6%) were seropositive by IFAT and ELISA, respectively. Brain tissues (n=60) and the pools of organs (n=65) were negative in the PCR. Our results showed a high prevalence of antibodies in free-range chickens and that IFAT is the more sensitive technique for the detection of anti-N. caninum antibodies.

Neospora caninum: a new class of biopharmaceuticals in the therapeutic arsenal against cancer

BACKGROUND

Microorganisms that can be used for their lytic activity against tumor cells as well as inducing or reactivating antitumor immune responses are a relevant part of the available immunotherapy strategies. Viruses, bacteria and even protozoa have been largely explored with success as effective human antitumor agents. To date, only one oncolytic virus-T-VEC-has been approved by the US Food and Drug Administration for use in biological cancer therapy in clinical trials. The goal of our study is to evaluate the potential of a livestock pathogen, the protozoan Neospora caninum, non-pathogenic in humans, as an effective and safe antitumorous agent.

METHODS/RESULTS

We demonstrated that the treatment of murine thymoma EG7 by subcutaneous injection of N. caninum tachyzoites either in or remotely from the tumor strongly inhibits tumor development, and often causes their complete eradication. Analysis of immune responses showed that N. caninum had the ability to 1) lyze infected cancer cells, 2) reactivate the immunosuppressed immune cells and 3) activate the systemic immune system by generating a protective antitumor response dependent on natural killer cells, CD8-T cells and associated with a strong interferon (IFN)-γ secretion in the tumor microenvironment. Most importantly, we observed a total clearance of the injected agent in the treated animals: N. caninum exhibited strong anticancer effects without persisting in the organism of treated mice. We also established in vitro and an in vivo non-obese diabetic/severe combined immunodeficiency mouse model that N. caninum infected and induced a strong regression of human Merkel cell carcinoma. Finally, we engineered a N. caninum strain to secrete human interleukin (IL)-15, associated with the alpha-subunit of the IL-15 receptor thus strengthening the immuno-stimulatory properties of N. caninum. Indeed, this NC1-IL15hRec strain induced both proliferation of and IFN-γ secretion by human peripheral blood mononuclear cells, as well as improved efficacy in vivo in the EG7 tumor model.

CONCLUSION

These results highlight N. caninum as a potential, extremely effective and non-toxic anticancer agent, capable of being engineered to either express at its surface or to secrete biodrugs. Our work has identified the broad clinical possibilities of using N. caninum as an oncolytic protozoan in human medicine.

Neospora caninum infection in Iran (2004-2020): A review

Knowledge on neosporosis and associated risk factors in different species of animals are so important for designing the control programs and reduce the economic losses globally. This literature review targeted for evaluating the infection rate of Neospora caninum in animals in Iran. Until April 2020, all of published documents in the main English and Persian-language databases were searched. A total number of 110 documents (English = 85 and Persian = 25) were extracted. Most of reports were sero-epidemiological studies using ELISA in Iranian cattle population. The range of Neospora infection was 3.8–76.2% in cattle, 0–54.6% in dogs, 0.9–9.9% in sheep, 6.2% in goats, 19.2–55.9% in buffaloes, 20–42.2% in horses, 52% in donkeys, 3.2–27% in camels, 14% and 19% in cats, and 0–20.4% in rodents. This rate in birds was 17.3% in chicken, 9.8% and 30.4% in pigeons, 2.8% and 3.7% in sparrows, and 9.9% in hooded crows. This is a comprehensive literature review on Neospora infection in Iran at the first time. The infection of N. caninum is widespread in Iran especially in dogs and cattle population. This review can provide baseline information for future research. Study on other hosts especially on wild and exotic animals is recommended for exact estimate of neosporosis in Iran. Investigations into molecular diagnosis and genotyping of N. caninum strains are also needed; this will be helpful for developing vaccines and finding the connection among wild and domestic cycles of disease. Education on the risk factors associated with N. caninum infection for is suggested farmers and rural public.

Molecular survey for cyst-forming coccidia (Toxoplasma gondii, Neospora caninum, Sarcocystis spp.) in Mediterranean periurban micromammals

Rodents and other micromammals constitute important reservoirs of infectious diseases; their role in the life cycle of apicomplexan parasites such as Toxoplasma gondii, Neospora caninum, and Sarcocystis spp. still needs clarification. In the present study, we analyzed by PCR and Sanger sequencing methods the presence of specific parasite DNA within brain and heart tissues of 313 individuals of five synanthropic small mammal species (Apodemus sylvaticus, Mus spretus, M. musculus, Rattus rattus, and Crocidura russula) collected in Barcelona metropolitan area (NE Spain). In addition, PCR-RFLP and microsatellites were also used as tools for genotypic characterization of T. gondii and N. caninum, respectively. Specific DNA of T. gondii, N. caninum, and Sarcocystis spp. was detected in 0.3% (n = 1), 1.3% (n = 4), and 3.8% (n = 12) of the animals, respectively. No mixed infections were observed. Crocidura russula stood out as the main host for Sarcocystis spp. Toxoplasma gondii-specific DNA detected in a house rat was genetically characterized by PCR-RFLP, presenting type II and III alleles (SAG1 [II], SAG3 [II], GRA6 [II], c22-8 [III], Apico [III]). Also, unsuccessful DNA sequencing and microsatellite typing were attempted in N. caninum-positive samples, which suggested a lack of PCR specificity and open avenues to speculate the host competence of rodents for N. caninum. Likewise, Sarcocystis spp. identity was studied by alignment and phylogenetic analyses of cox1 and 28S rRNA sequences from the 14 positive samples. It resulted in at least three unknown organisms closely similar (95.7-100% cox1-sequence homology) to Sarcocystis pantherophisi from the Eastern rat snake (Pantherophis alleghaniensis) (KU891603), suggesting together with 28S rRNA sequences analyses, three Sarcocystis sp. with a life cycle conformed by rodents as intermediate host (IH) and snakes as definitive hosts (DH) infecting the periurban micromammals surveyed. Prevalence figures found in this first survey carried out in Spain agree with other international studies focused on periurban areas. Further surveys should be conducted in farms and their surroundings in order to unravel the role of wild micromammals in the epidemiology of such protozoan parasites affecting our livestock, and therefore human population.

Neospora caninum infection in dairy farms with history of abortion in West of Iran

Neospora caninum is a major cause of abortion and economic losses among dairy farms in Iran and other countries. The main goal of current investigation was to evaluate the presence of antibodies against N. caninum and associated risk factors in dairy herds with history of abortion in Hamedan province of West Iran. A total numbers of 476 and 185 blood samples of pregnant cattle and farm dogs from 10 dairy farms with history of abortion were randomly collected. Bulk milk sample was taken from each farm. All samples were subjected for detection of IgG antibody against N. caninum using ELISA technique. Of all examined animals, 24.8% of cattle and 8.65% of dogs were seropositive to N. caninum. The seroprevalence had significant differences with abortion, stillbirth, metritis, breed, close contact to dogs, wild carnivores, rodents, poultry, and pregnancy using artificial insemination method. There were no significant differences among seroprevalence and different age groups, number and stage of gestation, and herd population. In all investigated farms, bulk milk examination was positive. In examined dogs, there was significant difference between seroprevalence and sex. It was concluded that N. caninum infection may be responsible for abortion and economic losses in dairy farms of the region. This was also the first comprehensive report on associated risk factors to N. caninum infection in dairy farms in the region.

Toxoplasma gondii and Neospora caninum infections in synanthropic rodents from Argentina

Abstract Toxoplasma gondii and Neospora caninum are closely related coccidian parasites (phylum Apicomplexa). This is the first study from urban synanthropic rodent species that involved serological and molecular diagnosis of T. gondii and N. caninum infection, and genotyping of T. gondii in Argentina. A total of 127 rodent samples were trap captured: Mus musculus (n = 78), Rattus norvegicus (n = 26) and Rattus rattus (n = 23). Antibodies against T. gondii and N. caninum were detected by IFAT in 32.8% (40/122) and 0.8% (1/122) of rodent samples, respectively, demonstrating contact with these protozoans. Additionally, T. gondii DNA was detected in 3.3% (4/123) of rodent central nervous system samples and 2 samples were genotyped by multilocus nPCR-RFLP. Neospora caninum DNA was not detected by PCR. The 2 genotyped samples were type III allele for all markers except for SAG-1 (type I for Rat1Arg and type II/III for Rat2Arg) and were identified as #48 and #2 (likely) according to the allele combinations reported on Toxo DB (Toxo-DB). The results of the present study revealed a wide distribution of T. gondii and less for N. caninum, in synanthropic rats and mice in the studied area.

Aetiology of livestock fetal mortality in Mazandaran province, Iran

In the farming industry, the productivity of livestock herds depends on the fertility efficiency of animals. The accurate diagnosis of a broad range of aetiological agents causing fetal death is often difficult. Our aim was to assess the prevalence rates of Toxoplasma gondii, Neospora caninum, and Brucella spp. infections in ruminant abortion using bacteriological culture and molecular techniques in Mazandaran Province, northern Iran. Samples were collected from 70 aborted sheep, goat, and cattle fetuses between September 2014 and December 2015. Necropsy was performed on all the received samples, and brain tissue and abomasal content were obtained from the aborted fetuses. Protozoan infections were detected by specific polymerase chain reaction (PCR) and bacterial agents using bacteriological examinations and PCR assay. Infectious pathogens were detected in 22 out of 70 (31.4%) examined fetuses. Moreover, T. gondii, N. caninum, and B. melitensis were verified in 13 (18.6%), four (5.7%), and two (2.85%) samples, respectively. Our results showed that infection with the mentioned pathogenic agents may lead to fetal mortality, which can be a major cause of economic loss. The listed pathogens could be considered important etiological agents of fetal loss in Mazandaran Province, for which appropriate control measures such as vaccination and biosecurity can be implemented to prevent infection and reduce reproductive loss in livestock farms.

Ocorrência de anticorpos anti-Toxoplasma gondii e anti-Neospora caninum em ovinos com distúrbios reprodutivos e fatores de risco

RESUMO: Objetivou-se avaliar a ocorrência, sinais clínicos e fatores de risco associados a soropositividade para Toxoplasma gondii e Neospora caninum em ovinos. Foram utilizados 294 animais com histórico de distúrbios reprodutivos de 28 fazendas do estado de São Paulo, Brasil, diagnosticados através da imunofluorescência indireta (1:64 e 1:50). A ocorrência de T. gondii foi de 29,9% (88/294) e de N. caninum 18% (53/294), sendo 3,7% (11/294) dos ovinos soropositivos para ambos. Observou-se com maiores chances à infecção pelo T. gondii: ovinos mestiços (p=0,04), Santa Inês (p=0,006), fornecimento de pastagem (p<0,001) ou associada a concentrado (p<0,001), uso exclusivamente de monta natural (p=0,002, OR=2,28 e IC95%=1,37-3,79) e a presença de aves nas propriedades (p=0,001). Na infecção por N. caninum essa chance aumentou em: fêmeas (p=0,031), propriedades sem aprisco (p<0,001) e sistema de criação semi-intensivo (p<0,001). Em relação ao histórico de problemas reprodutivos, ovelhas infectadas pelo N. caninum e T. gondii apresentaram redução da chance de apresentarem abortamento (p=0,044) e repetição de estro (p=0,025) respectivamente. O T. gondii esteve mais presente sorologicamente que o N. caninum em ovinos com histórico de distúrbios reprodutivos e apesar de suas semelhanças, diferiram epidemiologicamente em aspectos relacionados as características da criação como raça, sexo, sistema de criação, tipo de alimentação e manejo reprodutivo.

Toxoplasma gondii and Neospora caninum in Tolai Hares (Lepus tolai) Intended for Human Consumption in China: Seroprevalence, DNA Detection, and Genotyping

Currently, there is no information available on the detection of Toxoplasma gondii and Neospora caninum in the tissues of Tolai hares in China. This study aimed to investigate the prevalence of these protozoan parasites in Tolai hares obtained from Shandong province, eastern China, between January 2016 and June 2017. Serum and brain tissue samples of 358 Tolai hares were obtained and detected for the presence of antibody and parasite DNAs by serodiagnosis and polymerase chain reaction (PCR), respectively. The seroprevalence of T. gondii and N. caninum infection in Tolai hares was 8.10% (29/358) and 0.84% (3/358), respectively. However, all the 358 tested Tolai hares were negative for N. caninum by PCR and T. gondii DNA was detected in 23 Tolai hares (6.42%, 23/358). The positive T. gondii DNA was genotyped at 11 genetic markers using multilocus PCR-restriction fragment length polymorphism technology. Of the 23 positive samples, only 2 of them produced complete genotyping results, and were identified as ToxoDB Genotype #9. This is the first report to detect T. gondii in the tissues of Tolai hares from China and the first study to focus on N. caninum in Tolai hares from China.

Small rodents as paratenic or intermediate hosts of carnivore parasites in Berlin, Germany

Rodents are important intermediate and paratenic hosts for carnivore parasites, including the important zoonotic agents Toxoplasma, Echinococcus and Toxocara. Monitoring of such parasites in rodents can be used to detect increasing risks for human and veterinary public health. Rodents were trapped at four sites in Berlin, two near the city center, two at the periphery. PCRs were conducted to detect Coccidia (target ITS-1) and specifically Toxoplasma gondii (repetitive element) in brain and ascarids (ITS-2) in muscle or brain tissue. During necropsies, metacestodes were collected and identified using ITS-2 and 12S rRNA PCRs. An ELISA to detect antibodies against Toxocara canis ES antigens was performed. Within the 257 examined rodents, the most frequently observed parasite was Frenkelia glareoli predominantly found in Myodes glareolus. T. gondii was only detected in 12 rodents and Microtus spp. (although strongly underrepresented) had a significantly increased chance of being positive. Neither Echinococcus nor typical Taenia parasites of dogs and cats were found but Mesocestoides litteratus and Taenia martis metacestodes were identified which can cause severe peritoneal or ocular cysticercosis in dogs, primates and humans. Using PCR, the ascarids T. canis (n = 8), Toxocara cati (4) and Parascaris sp. (1) were detected predominantly in muscles. Seroprevalence of T. canis was 14.2% and ELISA was thus more sensitive than PCR to detect infection with this parasite. Non-parametric multidimensional scaling and cluster analysis revealed that parasite communities could be grouped into an urban and a peri-urban cluster with high frequency of ascarid-positive rodents in urban and high frequency of F. glareoli in peri-urban sites. Prevalence rates of parasites in rodents with potential impact for human or veterinary public health are considerable and the monitoring of transmission cycles of carnivore parasites in intermediate rodent hosts is recommended to estimate the health risks arising from wild and domesticated carnivores.

Investigations into the role of rats as intermediate hosts for Neospora caninum in Chennai, India

Attempts were made to detect Neospora caninum in rats (Rattus rattus) in and around Chennai, India. During the study, 112 feral rats were trapped and blood, brain, heart, lungs and diaphragm samples were collected for serological, parasitological and molecular identification of N. caninum. Out of 112 rats, cyst-like structures were identified in 16 brain squash samples. However, the identity of the cysts could not be confirmed as N. caninum. A total of 12 sera samples were positive for N. caninum by indirect fluorescence antibody test (IFAT). Four of the 'cyst' positive samples were also positive by IFAT. None of the above samples showed amplification of N. caninum (Nc5) or toxoplasmatiid (ITS-1) fragments by PCR. In conclusion, the present study showed 10.71% seroprevalence of N. caninum among feral rats, which is a first report in India. Low prevalence of the organism in the environment and the consequent low chance of exposure of rats to N. caninum might explain the failure to detect the DNA in any of the samples tested in the study.

Molecular detection of Neospora caninum in house sparrows (Passer domesticus) in Iran

Neospora caninum is an intracellular protozoan parasite with a wide range of intermediate bird hosts. There is little information describing the prevalence and genetic characterization of N. caninum in bird hosts worldwide and in Iran. In this study, a total of 217 brain samples of house sparrow (Passer domesticus) were examined for N. caninum presence by nested polymerase chain reaction targeting the Nc-5 gene. N. caninum DNA was detected in 3.68% (8/217) of sparrows. Sequencing of the Nc5 genomic DNA revealed 97-99% of similarity with N. caninum sequences deposited in Genbank. To our knowledge, this study is the first molecular evidence of N. caninum DNA in bird hosts in Iran. The results of this study highlight the role of the house sparrow (Passer domesticus) in maintaining and spreading N. caninum infection to canines in the feral and domestic environment.

Role of vertical transmission of Toxoplasma gondii in prevalence of infection

The parasite, Toxoplasma gondii, is a highly successful pathogen that infects around 30% of the global human population. Additionally, it is able to infect all warm blooded animals with high prevalence. This is surprising as it is a parasite of the cat and can only complete its full sexual cycle in that host. This review examines the important key routes of transmission: infective oocysts from the cat, ingestion of raw infected tissue and vertical transmission. The latter route of transmission has traditionally been thought to be rare. In this review, this assumption is examined and discussed in the light of the current literature. The available evidence points to the possibility that vertical transmission occurs frequently in natural populations of mice however the evidence in sheep is currently ambivalent and controversial. In humans, the situation appears as though vertical transmission may be rare although there is still much that is unexplained.

Identification of latent neosporosis in sheep in Tehran, Iran by polymerase chain reaction using primers specific for the <i>Nc-5</i> gene

Little is known about latent infection and molecular characterisation of Neospora caninum in sheep (Ovis aries). In this study, 330 sheep samples (180 hearts and 150 brains) were analysed for N. caninum DNA by nested polymerase chain reaction (PCR) targeting the Nc-5 gene. Neospora caninum DNA was detected in 3.9% (13/330) of sheep samples. The parasite's DNA was detected in 6.7% of heart samples (12/180) and 0.7% (1/150) of brain samples. No clinical signs were recorded from infected or uninfected animals. Sequencing of the genomic DNA revealed 96% - 99% similarity with each other and 95.15% - 100% similarity with N. caninum sequences deposited in GenBank. To our knowledge, this is the first report on the use of PCR to identify latent neosporosis in sheep in Iran. The results of this study have the potential to contribute to our understanding of the role of N. caninum-infected sheep in the epidemiology of neosporosis.

A review of neosporosis and pathologic findings of Neospora caninum infection in wildlife

Neospora caninum is an apicomplexan parasite that is the etiologic agent of neosporosis, a devastating infectious disease regarded as a major cause of reproductive loss in cattle and neuromuscular disease in dogs worldwide. This protozoan pathogen is maintained in the environment by a heteroxenous life cycle that involves a definitive canid host and a wide range of intermediate hosts. In recent years, a number of wildlife species have been investigated for their possible involvement in the N. caninum life cycle and many have been implicated as intermediate hosts. However, in many instances these studies have utilized serological and molecular techniques to detect infection in clinically normal animals, and investigation of possible associated morbidity, mortality, and pathology has been neglected. As such, the occurrence and importance of Neospora-associated disease in wildlife species are unknown. In order to improve our understanding of the significance of N. caninum infection in nondomestic species, the present review provides an up-to-date summary of clinical neosporosis and N. caninum-associated pathologic lesions in naturally and experimentally infected wildlife species. We provide a list of all free-ranging and captive wildlife species identified with N. caninum infection to date using currently available diagnostic tools. The advantages and disadvantages of diagnostic methods in wildlife are addressed in order to recommend optimal diagnosis of confirming N. caninum infection and neosporosis in nondomestic species. Although current data would suggest that N. caninum infection does not adversely impact wildlife populations, there is a need for greater international uniformity in the diagnosis of N. caninum infection and neosporosis in nondomestic species in order to assess the true consequences of parasite infection.

Prevalence and genotyping of Toxoplasma gondii in naturally-infected synanthropic rats (Rattus norvegicus) and mice (Mus musculus) in eastern China

Background

Synanthropic rats and mice share the same environment with humans and play an important role in epidemiology of toxoplasmosis; however, there is limited information about prevalence and genetic characterization of Toxoplasma gondii in synanthropic rats and mice in China.

Findings

In the present study, the prevalence and genetic characterization of T. gondii naturally infected synanthropic rodents (Rattus norvegicus and Mus musculus) were investigated in the urban area of Xuzhou city, Eastern China between June 2013 and August 2014. DNA from the brain of each animal was prepared and screened by specific PCR assay targeting 35-fold repeated B1 gene (B1-PCR). PCR positive DNA samples were further genotyped by multi-locus PCR-RFLP. Overall, out of 123 synanthropic rodents, 29 samples were positive by B1 gene-targeted PCR (23.6%). Of these, 7 out of 31 (22.3%) M. musculus were positive, whereas the positive rate of R. norvegicus was 23.9% (22/92). Multi-locus PCR-RFLP analysis reveals that seven PCR-positive samples were completely genotyped and they were identified as type China 1 (ToxoDB# 9).

Conclusion

To our knowledge, this is the first report of molecular detection and genetic characterization of T. gondii infection in synanthropic rodents in Eastern China. The results of the present study showed a high infection pressure of T. gondii exists in the environment and synanthropic rodents infected by T. gondii may be an important source of infection for cats and other animals.

Prevalence ofToxoplasma gondiiin localized populations ofApodemus sylvaticusis linked to population genotype not to population location

Toxoplasma gondiiis a globally distributed parasite infecting humans and warm-blooded animals. Although many surveys have been conducted forT. gondiiinfection in mammals, little is known about the detailed distribution in localized natural populations. In this study, host genotype and spatial location were investigated in relation toT. gondiiinfection. Wood mice (Apodemus sylvaticus) were collected from 4 sampling sites within a localized peri-aquatic woodland ecosystem. Mice were genotyped using standardA. sylvaticusmicrosatellite markers andT. gondiiwas detected using 4 specific PCR-based markers: SAG1, SAG2, SAG3 and GRA6 directly from infected tissue. Of 126 wood mice collected, 44 samples were positive giving an infection rate of 34·92% (95% CI: 27·14–43·59%). Juvenile, young adults and adults were infected at a similar prevalence, respectively, 7/17 (41·18%), 27/65 (41·54%) and 10/44 (22·72%) with no significant age-prevalence effect (P = 0·23). Results of genetic analysis of the mice showed that the collection consists of 4 genetically distinct populations. There was a significant difference inT. gondiiprevalence in the different genotypically derived mouse populations (P = 0·035) but not between geographically defined populations (P = 0·29). These data point to either a host genetic/family influence on parasite infection or to parasite vertical transmission.

Comparison of an ELISA assay for the detection of adhesive/invasive Neospora caninum tachyzoites

Neospora caninum belongs to the phylum Apicomplexa, the causative agent of neosporosis, which leads to economic impacts on cattle production. A common feature among apicomplexan parasites is the invasive process driven mostly by the parasite. As a first evaluation of candidate molecules that play a possible role by interfering in this invasive process, the in vitro invasion assay is a fast and direct way to screen future agonists or antagonists. This work involved the development of a new cell culture ELISA and transient β-galactosidase activity applied to the semi-quantitative detection of N. caninum in Vero cell culture. Cell culture ELISA is based on histochemistry and immunology, resulting in a colorimetric reaction. The β-galactosidase activity was obtained by the transient transfection of the lacZ gene under control of RPS13 promoter of N. caninum. These methods were used to evaluate the effects of temperature (37°C and 85°C) on the invasion and adhesion of tachyzoites. The three tested methods (real time PCR, β-galactosidase activity and ELISA) showed a similar pattern, indicating that different methods may be complementary.

Efficacy of magnetic capture in comparison with conventional DNA isolation in a survey of Toxoplasma gondii in wild house mice

Toxoplasma gondii is a zoonotic parasite with a world-wide distribution. House mice (Mus musculus) play an important role as a reservoir host in the parasite life cycle. However, their detection in mouse brain is limited because the host potentially harbours only a few tissue cysts. In order to improve the diagnosis, we tested a novel protocol for T. gondii detection in mice and compared this technique to a standard PCR-based protocol using a commercial kit for DNA isolation. Efficacy of magnetic capture for isolation of T. gondii DNA from whole host brains was tested in brain samples of laboratory mice spiked with 1 up to 10(4) tachyzoites. Real-time PCR revealed that even 1-5 tachyzoites can be detected after magnetic capture. Also this method is suitable to quantify parasite numbers in mouse brains with more than 10 tachyzoite equivalents. To assess the two techniques in wild mice, we employed a dataset consisting of 243 individuals. The prevalence of T. gondii detected by magnetic capture and qPCR and by commercial isolation and PCR was 1.2% and 0%, respectively. The magnetic capture and quantitative PCR seems to be a highly sensitive and specific diagnostic method for both laboratory research and wild population surveys.

Neospora caninum and Wildlife

Bovine neosporosis caused by Neospora caninum is among the main causes of abortion in cattle nowadays. At present there is no effective treatment or vaccine. Serological evidence in domestic, wild, and zoo animals indicates that many species have been exposed to this parasite. However, many aspects of the life cycle of N. caninum are unknown and the role of wildlife in the life cycle of N. caninum is still not completely elucidated. In North America, there are data consistent with a sylvatic cycle involving white tailed-deer and canids and in Australia a plausible sylvatic cycle could be occurring between wild dogs and their macropod preys. In Europe, a similar sylvatic cycle has not been established but is very likely. The present review is a comprehensive and up to date summary of the current knowledge on the sylvatic cycle of N. caninum, species affected and their geographical distribution. These findings could have important implications in both sylvatic and domestic cycles since infected wildlife may influence the prevalence of infection in cattle farms in the same areas. Wildlife will need to be taken into account in the control measures to reduce the economical losses associated with this important disease in cattle farms.

A molecular and ecological analysis of the trematodePlagiorchis elegansin the wood mouseApodemus sylvaticusfrom a periaquatic ecosystem in the UK

The prevalence of the digeneanPlagiorchissp. was investigated in a natural wood mouse population (Apodemus sylvaticus) in a periaquatic environment. Classical identification was complemented with the use of molecular differentiation to determine prevalence and verify species identity. Use of the complete ITS1-5.8S rDNA-ITS2 and partial 28S rDNA gene sequences have confirmed that the species reported at this location wasPlagiorchis elegansand notPlagiorchis murisas reported previously. This underlines the difficulties in identification of these morphologically similar parasites.Plagiorchis elegansis typically a gastrointestinal parasite of avian species but has also been reported from small mammal populations. Although the occurrence of this digenean inA. sylvaticusin the UK is rare, in the area immediately surrounding Malham Tarn, Yorkshire, it had a high prevalence (23%) and a mean worm burden of 26.6 ± 61.5. The distribution ofP. elegansfollowed a typically overdispersed pattern and both mouse age-group and sex were determined to be two main factors associated with prevalence. Male mice harboured the majority of worms, carrying 688 of 717 recovered during the study, and had a higher prevalence of 32.4% in comparison to only 8.7% in the small intestine of female mice. A higher prevalence of 43% was also observed in adult mice compared to 14% for young adults. No infection was observed in juvenile mice. These significant differences are likely to be due to differences in the foraging behaviour between the sexes and age cohorts of wood mice.

Screening for Toxoplasma gondii in aborted bovine fetuses in Brazil

The aim of this study was to determine if Toxoplasma gondii was present in aborted bovine fetuses in Brazil. Histopathology of 105 cases with suspected infectious abortion, analyzed during the period from 2006 to 2008 at Centro de Pesquisa e Desenvolvimento de Sanidade Animal of Instituto Biológico, São Paulo, showed 75 cases with indications of abortion due to apicomplexan protozoa. These cases were submitted to PCR for verification of the laboratory diagnosis. Fetal DNA was extracted from central nervous system, heart, liver, muscle, and/or placenta samples to obtain a 529 bp DNA fragment. T. gondii DNA was not detected in any of the bovine fetuses analyzed, suggesting that it may not be a frequent cause of bovine abortion.

Investigating the role of wild carnivores in the epidemiology of bovine neosporosis

Neospora caninum is a protozoan parasite, primarily associated with bovine abortion. The only definitive hosts discovered to date are carnivores. This study aimed to identify the role of mammalian carnivores in the epidemiology of bovine neosporosis. A sample bank of serum, fecal and brain samples was established: American mink (Mustela vison), red foxes (Vulpes vulpes), pine martens (Martes martes), badgers (Meles meles), stoats (Mustela erminea), otters (Lutra lutra) and feral ferrets (Mustela putorius). Approximately 1% of mink and 1% of fox samples were positive by IFAT. According to PCR analysis of DNA extracted from brain tissue, 3% of the mink, 4% of the otters and 6% of the foxes examined were infected with N. caninum. All fecal samples tested negative for N. caninum DNA (n = 311), suggesting that the species that tested positive were intermediate not definitive hosts. This is the first time that tissues from mustelids have tested positive for N. caninum. The need to test 2 relatively large (~200 mg) targeted parts of the brain to avoid false negatives was also identified. The relatively low prevalence of N. caninum in Irish carnivores suggests that the local ecology of a species has an important influence on its epidemiological role.

Neospora caninum as causative agent of bovine encephalitis in Brazil

For supporting the Brazilian bovine encephalitis surveillance program this study examined the differential diagnosis of Neospora caninum in central nervous system (CNS) by histological analysis (HE staining), immunohistochemistry (IHC), and nested-PCR using a set of primers from the Nc5 region of the genomic DNA and ITS1 region of the ribosomal DNA. A sample of 302 cattle presenting neurological syndrome and negative for rabies, aged 0 to 18 years, from herds in 10 Brazilian states was evaluated for N. caninum from January 2007 to April 2010. All specimens tested negative with IHC and nested-PCR using primers from the ITS1 region of ribosomal DNA, while two positive cases (0.66%) were found using primers from the Nc5 region of genomic DNA: a 20 month-old male and a 72 month-old female, both from São Paulo State. Only the male presented severe multifocal necrotizing encephalitis associated with mononuclear cell infiltration, a pathognomonic lesion caused by parasites of the family Sarcocystidae, and only this case was associated with N. caninum thus representing 0.33% positivity. Future studies should explore the association of IHC and nested-PCR with real-time PCR, a quantitative method that could be standardized for improving the detection of N. caninum in bovine CNS specimens.

Occurrence of Neospora caninum and Toxoplasma gondii infections in ovine and caprine abortions

Neospora caninum and Toxoplasma gondii are closely related cyst-forming apicomplexan parasites identified as important causes of reproductive failure in cattle and small ruminants, respectively. Protozoan abortion in small ruminants is traditionally associated with T. gondii, but the importance of N. caninum remains uncertain. The aim of this study was to investigate the presence of N. caninum and T. gondii infections in abortion cases in small ruminants submitted for diagnosis. For this purpose, 74 ovine and 26 caprine aborted foetuses were recovered from different areas in Spain. Foetal histopathology was used to detect the presence of protozoal-associated lesions in brain. The presence of N. caninum and T. gondii was confirmed by PCR. Protozoal infection was detected in 17 out of 100 (17%) foetuses examined by at least one of the diagnostic techniques used. Lesions suggestive of protozoal infection were observed in 10.8% (8/74) and 15.4% (4/26) of the ovine and caprine abortions respectively. N. caninum and T. gondii infection was detected by PCR in 6.8% (5/74) and 5.4% (4/74) of sheep foetuses, respectively, of which five showed protozoal-associated lesions. N. caninum DNA was detected in 11.5% (3/26) of goat foetuses, of which two showed protozoal-associated lesions, whereas T. gondii DNA was detected in one goat foetus with no lesions. The simultaneous presence of N. caninum and T. gondii DNA was detected in one sheep foetus with severe lesions. This study demonstrates that N. caninum plays a significant role in abortion in small ruminants in the studied population. In addition, our results highlight the importance of differentiating between protozoa whenever characteristic lesions are observed.

Prevalence and co-infection of Toxoplasma gondii and Neospora caninum in Apodemus sylvaticus in an area relatively free of cats

The protozoan parasite Toxoplasma gondii is prevalent worldwide and can infect a remarkably wide range of hosts despite felids being the only definitive host. As cats play a major role in transmission to secondary mammalian hosts, the interaction between cats and these hosts should be a major factor determining final prevalence in the secondary host. This study investigates the prevalence of T. gondii in a natural population of Apodemus sylvaticus collected from an area with low cat density (<2·5 cats/km2). A surprisingly high prevalence of 40·78% (95% CI: 34·07%-47·79%) was observed despite this. A comparable level of prevalence was observed in a previously published study using the same approaches where a prevalence of 59% (95% CI: 50·13%-67·87%) was observed in a natural population of Mus domesticus from an area with high cat density (>500 cats/km2). Detection of infected foetuses from pregnant dams in both populations suggests that congenital transmission may enable persistence of infection in the absence of cats. The prevalences of the related parasite, Neospora caninum were found to be low in both populations (A. sylvaticus: 3·39% (95% CI: 0·12%-6·66%); M. domesticus: 3·08% (95% CI: 0·11%-6·05%)). These results suggest that cat density may have a lower than expected effect on final prevalence in these ecosystems.

Toxoplasmosis in naturally infected rodents in Belgrade, Serbia

To assess the role of synanthropic rodents in the epidemiology of urban toxoplasmosis, Toxoplasma gondii infection was examined in 144 rats (Rattus norvegicus) and 12 mice (Mus musculus) captured using live animal traps in three locations in Belgrade city characterized by poor housing and degraded environment. In rats, specific IgG antibodies were detected by modified agglutination test in 22 (27.5%) of the 80 blood samples available. Toxoplasma brain cysts were microscopically detected in 11 (7.6%), and Toxoplasma DNA by real-time polymerase chain reaction was demonstrated in 15 (10.4%) animals. Of these, both cysts and Toxoplasma DNA were detected in five (3.5%) rats. In mice, cysts were observed in 3 (25%), but Toxoplasma DNA was detected in even 10 (83.3%) animals, including all 3 with morphologically recognized cysts. Being a link in the chain of Toxoplasma infection, the existence of urban rodent reservoirs of infection represents a public health risk.