Coprodiagnosis of Hammondia heydorni in dogs by PCR based amplification of ITS 1 rRNA: differentiation from morphologically indistinguishable oocysts of Neospora caninum

Morphological and molecular identification of Sarcocystis falcatula from the emerald toucanet (Aulacorhynchus albivitta) in Colombia

Sarcocystis spp. are cyst-forming coccidia characterized by a two-host predator-prey life cycle. Sarcocysts are formed in muscles or nervous system of the intermediate host, while sporocysts develop in the small intestine of the definitive host. The intermediate hosts of Sarcocystis falcatula are wild birds. Colombia is one of the countries with the greatest biodiversity of birds, however, there are few studies related to this parasite in wild birds. This study presents the morphological and molecular detection of Sarcocystis falcatula collected from the emerald toucanet (Aulacorhynchus albivitta), a wild bird species endemic to South America. Pectoral muscle samples were obtained, and microscopic and molecular detection was performed by light microscopy, transmission electron microscopy, and amplifying of the first internal transcribed spacer (ITS-1) and surface antigen-encoding genes (SAGs). Sarcocystis measured an average of 161  × 42 μm, with a cyst wall ∼0.4 μm thick. Ultrastructurally, the sarcocyst wall type 11b-like consisted of numerous villar protrusions of 850 nm wide on average. The ITS-1 sequence showed 97.0-99.7% identity to S. falcatula previously described from birds in the United States and Brazil, respectively. Concatenated phylogenetic analysis based on SAG2, SAG3 and SAG4 confirmed that the new isolate is grouped with other sequences of Sarcocystis from South America, but divergent from those isolates obtained in North America. The results of this study demonstrate for the first time the presence of S. falcatula in a wild bird from Colombia.

Working towards the development of vaccines and chemotherapeutics against neosporosis-With all of its ups and downs-Looking ahead

Neospora caninum is an apicomplexan and obligatory intracellular parasite, which is the leading cause of reproductive failure in cattle and affects other farm and domestic animals, but also induces neuromuscular disease in dogs of all ages. In cattle, neosporosis is an important health problem, and has a considerable economic impact. To date there is no protective vaccine or chemotherapeutic treatment on the market. Immuno-prophylaxis has long been considered as the best control measure. Proteins involved in host cell interaction and invasion, as well as antigens mediating inflammatory responses have been the most frequently assessed vaccine targets. However, despite considerable efforts no effective vaccine has been introduced to the market to date. The development of effective compounds to limit the effects of vertical transmission of N. caninum tachyzoites has emerged as an alternative or addition to vaccination, provided suitable targets and safe and efficacious drugs can be identified. Additionally, the combination of both treatment strategies might be interesting to further increase protectivity against N. caninum infections and to decrease the duration of treatment and the risk of potential drug resistance. Well-established and standardized animal infection models are key factors for the evaluation of promising vaccine and compound candidates. The vast majority of experimental animal experiments concerning neosporosis have been performed in mice, although in recent years the numbers of experimental studies in cattle and sheep have increased. In this review, we discuss the recent findings concerning the progress in drug and vaccine development against N. caninum infections in mice and ruminants.

Prevalence of intestinal parasites in street dogs (Canis lupus familiaris) with highlights on zoonosis in Lalitpur, Nepal

BACKGROUND

The presence of intestinal parasites influences the growth and well-being of canids. Additionally, infected dogs and their faeces with considerably higher eggs/oocysts released per gram (epg/opg) of zoonotic parasites contribute to parasitic spillover to humans, domestic animals and sympatric wildlife.

OBJECTIVES

The current study aimed to reveal the prevalence of intestinal parasites (protozoa and helminths) and to list the zoonotically significant parasites in free-roaming street dogs in Lalitpur Metropolitan City, Nepal.

METHODS

Fresh faecal samples (n = 332) were collected from feral dogs of varying ages and sexes and transported to the research laboratory. The copro microscopic examination was carried out via direct wet mount, formalin ethyl acetate sedimentation, saturated salt flotation, acid-fast staining and sporulation techniques.

RESULTS

Coproscopy revealed an overall 95.7% (318/332) prevalence rate with 23 diverse species of intestinal parasites (10 protozoa and 13 helminths). Among them, 5 protozoa and 11 helminths possessed zoonotic potential, and their overall prevalence was 92.5%. Helminth's overall prevalence was double that of the protozoa (87.7% vs. 43%). Polyparasitism was dominant over mono parasitism (79.5% vs. 16.3%), and co-infection of up to seven species of parasites at a time was recorded.

CONCLUSIONS

Urban street dogs harboured a higher prevalence of intestinal parasites that varied with age and sex. Since most of the reported parasites are zoonotic, dog density and parasitic richness indicate a greater spillover risk to humans and domestic animals. Furthermore, this study also provides appropriate 'baseline' data for assessing effective control measures against parasitic infestations among street dogs and controlling their transmission to humans.

Acute, fatal Sarcocystis falcatula infection in rose-ringed parakeets (Psittacula krameri)

Sarcocystosis is an important avian disease that affects several intermediate host species. Birds not endemic from Americas, like Old World psittacine species, appear to be more susceptible to lethal infection than New World psittacine species. The aim of this study was to investigate the sudden death of rose-ringed parakeets (Psittacula krameri) in an exotic private parrot's aviary. Macroscopically, the most prevalent findings were severe lung congestion, slight superficial myocardial hemorrhagic lesions, enlarged liver and congestion of meningeal vessels. The initial diagnosis of sarcocystosis was made in all birds by microscopic observations of intravascular pulmonary schizonts, as well hepatitis, myocarditis, and nephritis. Immunohistochemistry for detection of Sarcocystis sp. antigen revealed an intense immunoreactivity in the lungs. Molecular identification of Sarcocystis falcatula were obtained by nested PCR and sequencing of amplified fragments of internal transcribed spacer 1 (ITS1) and three surface antigen-coding genes (SAG2, SAG3 and SAG4). SAG-based phylogenies showed a close relatedness of the isolate described here and S. falcatula previously detected in naturally infected native birds, which suggests that the isolates that affected ringnecks are a common isolate that circulates in Brazil.

Analytical sensitivity of a multiplex quantitative PCR for Toxoplasma gondii and Neospora caninum

Cyst-forming coccidia, Toxoplasma gondii and Neospora caninum, are recognised as important causes of animal disease. Molecular diagnostics based on the presence of DNA in animal tissue are required to specifically detect T. gondii and N. caninum while achieving high levels of analytical sensitivity. We optimised available single-plex probe base qPCR assays into a multiplexed qPCR panel to detect cyst-forming coccidia, i.e. T. gondii and N. caninum. The T. gondii assay is based on a 529-bp repetitive (REP) element and the N. caninum assay on the NC5 repetitive region. Using target sequence synthetic DNA, the limit of detection (LOD) was determined to be 100 copies, that is less than a single tachyzoite of either T. gondii or N. caninum. The T. gondii and N. caninum multiplexed qPCR assay optimised in this study can be used to effectively detect parasite DNA for diagnostic purposes in animal tissue.

Molecular analysis suggests that Namibian cheetahs (Acinonyx jubatus) are definitive hosts of a so far undescribed Besnoitia species

Background

Besnoitia darlingi, B. neotomofelis and B. oryctofelisi are closely related coccidian parasites with felids as definitive hosts. These parasites use a variety of animal species as intermediate hosts. North American opossums (Didelphis virginiana), North American southern plains woodrats (Neotoma micropus) and South American domestic rabbits (Oryctolagus cuniculus) are intermediate hosts of B. darlingi, B. neotomofelis and B. oryctofelisi, respectively. Based on conserved regions in the internal transcribed spacer-1 (ITS1) sequence of the ribosomal DNA (rDNA), a real-time PCR for a sensitive detection of these Besnoitia spp. in tissues of intermediate hosts and faeces of definitive hosts has recently been established. Available sequence data suggest that species such as B. akodoni and B. jellisoni are also covered by this real-time PCR. It has been hypothesised that additional Besnoitia spp. exist worldwide that are closely related to B. darlingi or B. darlingi-like parasites (B. neotomofelis, B. oryctofelisi, B. akodoni or B. jellisoni). Also related, but not as closely, is B. besnoiti, the cause of bovine besnoitiosis.

Methods

Faecal samples from two free-ranging cheetahs (Acinonyx jubatus) from Namibia that had previously tested positive for coccidian parasites by coproscopy were used for this study. A conventional PCR verified the presence of coccidian parasite DNA. To clarify the identity of these coccidia, the faecal DNA samples were further characterised by species-specific PCRs and Sanger sequencing.

Results

One of the samples tested positive for B. darlingi or B. darlingi-like parasites by real-time PCR, while no other coccidian parasites, including Toxoplasma gondii, Hammondia hammondi, H. heydorni, B. besnoiti and Neospora caninum, were detected in the two samples. The rDNA of the B. darlingi-like parasite was amplified and partially sequenced. Comparison with existing sequences in GenBank revealed a close relationship to other Besnoitia spp., but also showed clear divergences.

Conclusions

Our results suggest that a so far unknown Besnoitia species exists in Namibian wildlife, which is closely related to B. darlingi, B. neotomofelis, B. oryctofelisi, B. akodoni or B. jellisoni. The cheetah appears to be the definitive host of this newly discovered parasite, while prey species of the cheetah may act as intermediate hosts.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-04697-3.

Molecular Characterization of New Haplotype of Genus Sarcocystis in Seabirds from Magdalena Island, Southern Chile

Simple Summary

Sarcocystidae is a family of apicomplexan protozoa highly prevalent in vertebrates. The definitive hosts of sarcocystids eliminate oocysts or sporocysts that infect intermediate hosts. After infection, mature tissue cysts (sarcocysts) develop in intermediate hosts, mostly in muscle and neurological tissues. Sarcocysts are infectious for definitive hosts, which acquire them through carnivorous or scavenging habits. Intermediate hosts and definitive hosts are the natural hosts of sarcocystids in which infections are usually mildly or not symptomatic. In 2017, muscular and neurological tissues of 22 birds from Magdalena Islands, southern coast of Chile, were screened for the presence of DNA of sarcocystids. DNA of organisms of the genus Sarcocystis was identified in two Chilean skuas (Stercorarius chilensis). The genetic makeup of the parasite detected in skuas was unprecedented and probably represent a new species in the genus. It is well known that Sarcocystis may cause severe infections in aberrant hosts, which are susceptible animals that do not behave as natural hosts for the parasite and have low resistance to the infection, thus more studies are needed to characterize this parasitosis in skuas and other hosts to understand the epidemiology of the infection and its impact on the health of marine fauna.

Abstract

Evidence of sarcocystid infection was investigated in samples of 16 penguins (Spheniscus. magellanicus), four Dominican gulls (Larus dominicanus) and two Chilean skuas (Stercorarius chilensis) found in Madalenas Islands, Chile, in 2017. Samples of skeletal muscle, cardiac muscle and brain from all birds were screened by a pan-sarcocystid nested-PCR targeting a short fragment of the gene encoding the small ribosomal unit (nPCR-18Sa). The only two positive samples by nPCR-18Sa, both from skuas, were tested by a nested-PCR directed to the internal transcribed spacer 1 (nPCR-ITS1), also a pan-sarcocystidae nested-PCR, and to a nested-PCR directed to the B1 gene (nPCR-B1), for the exclusive detection of Toxoplasma gondii. The two nPCR-18Sa-positive samples were nPCR-ITS1-positive and nPCR-B1-negative. The nPCR-ITS1 nucleotide sequences from the two skuas, which were identical to each other, were revealed closely related to homologous sequences of Sarcocystis halieti, species found in seabirds of northern hemisphere. Larger fragments of genes encoding 18S and partial sequences of genes coding for cytochrome oxidase subunit 1 were also analyzed, corroborating ITS1 data. The haplotypes found in the skuas are unprecedent and closely related to species that use birds as the definitive host. Further studies need to be carried out to detect, identify and isolate this parasite to understand the epidemiology of the infection and its impact on the health of marine fauna.

Copro-molecular diagnosis of the Toxoplasmatinae subfamily in dog and cat populations in northern Iran

OBJECTIVES

The oocysts of the Toxoplasmatinae subfamily (Neospora caninum, Hammondia hammondi and H. heydorni, and Besnoitia besnoiti) are morphologically similar to Toxoplasma gondii, and indistinguishable from each other. This study investigated the prevalence of the Toxoplasmatinae subfamily in dog and cat fecal samples using a nested polymerase chain reaction method.

METHODS

Overall, 200 fecal samples from domestic dogs (n=120) and cats (n=80) were collected from 15 farms in northern Iran. The samples were homogenized in 2.5% potassium dichromate solution and subsequently concentrated with sucrose solution. DNA was extracted from samples using a genomic DNA kit. Specific primers and the 18S rDNA gene were used to screen and detect all Toxoplasmatinae oocysts.

RESULTS

Overall, 2.5% (3 of 120) and 22.5% (18 of 80) of the fecal samples collected from dogs and cats were infected with Toxoplasmatinae. In dogs, 2 samples were positive for N. caninum and 1 sample was positive for T. gondii. In cats, all 18 positive samples belonged to T. gondii. No contamination with H. heydorni was observed in dog fecal samples or H. hammondi and B. besnoiti in cat fecal samples. A phylogenetic analysis revealed that the T. gondii (cat) and N. caninum (dog) found had similarities with parasites reported from other regions of the world.

CONCLUSIONS

This is the first study to provide data on the epidemiology of Toxoplasmatinae oocysts in Iran. The findings suggest that public-health monitoring for the effective control of feces from cats and dogs and improved pet hygiene habits are needed.

High Exposure to Toxoplasma gondii and Neospora Spp. in Donkeys in Israel: Serological Survey and Case Reports

Simple Summary

Toxoplasma gondii and Neospora spp. are major pathogenic parasites of animals worldwide, with the first also affecting humans. These parasites have two-host life cycles, with the cat and the dog being the definitive hosts of T. gondii and N. caninum, respectively. Both parasites can infect various animal species, as intermediate hosts, in which they form tissue cysts and may cause abortions and neurological disease. Both parasites have been reported in wild and domestic animals in Israel. This study aimed to evaluate the serologic exposure of donkeys to these parasites. A total of 98 donkeys were examined. Half of them (n = 49) were from animal shelters in Israel, and the rest (n = 49) were working donkeys from the Palestinian Authority. Anti-T. gondii antibodies and anti-Neospora spp. antibodies were found in 94% and in 70% of the donkeys, respectively. In addition, two cases of donkeys presenting N. caninum tissue cysts, which were detected during post-mortem examination, were described. This is the first report of the exposure of donkeys to Toxoplasma gondii and Neospora spp. in the area. The exposure of donkeys to both parasites was considerably higher than the exposure of other species in the area and may be the result of poor husbandry conditions and higher exposure to infection. These results indicate that donkeys may have an important role in the maintenance and transmission of these parasites.

Abstract

Toxoplasma gondii and Neospora spp. are closely related cyst-forming coccidian parasites, which infect various animal species and have considerable zoonotic and economic implications, respectively. Both parasites are endemic in Israel and have been reported to infect wild and domestic animals. This study was conceived to evaluate the serologic exposure of donkeys to these parasites. Serum samples were collected from 98 donkeys. Half of them (n = 49) were from animal shelters in Israel, and the rest (n = 49) were working donkeys from the Palestinian Authority. The donkeys were screened for the presence of anti-Toxoplasma and anti-Neospora antibodies by immunofluorescence antibody tests (IFATs). The seroprevalence of T. gondii and Neospora spp. was 94% and 70%, respectively, and 69% of the donkeys were exposed to both parasites. In addition, N. caninum tissue cysts were documented in two donkeys during post-mortem examination. This is the first report of the exposure of donkeys to T. gondii and Neospora spp. in the area. The high prevalence found in this study suggests that donkeys may have a role in the maintenance of these parasites in the area, thus serving as a source of infection for the definitive hosts.

First molecular characterization of Sarcocystis neurona causing meningoencephalitis in a domestic cat in Brazil

Sarcocystis neurona is the main agent associated with equine protozoal myeloencephalitis (EPM). Apart from horses, S. neurona has been occasionally described causing neurologic disease in several other terrestrial animals as well as mortality in marine mammals. Herein, we describe the clinical, pathological, and molecular findings of a fatal case of S. neurona-associated meningoencephalitis in a domestic cat. The causing agent was analyzed by multilocus genotyping, confirming the presence of S. neurona DNA in the tissue samples of the affected animal. Significant molecular differences were found in relation to S. neurona isolates detected in other regions of the Americas. In addition, the parasite was identical to Sarcocystis sp. identified in opossum sporocysts in Brazil at molecular level, which suggests that transmission of. S. neurona in Brazil might involve variants of the parasite different from those found elsewhere in the Americas. Studies including more samples of S. neurona would be required to test this hypothesis, as well as to assess the impact of this diversity.

Contribution of introns to the species diversity associated with the apicomplexan parasite, Neospora caninum

Neospora caninum is an intracellular parasite considered a leading cause of bovine reproduction failure worldwide, and a serious neurological disease of canines. Transplacental transmission in intermediate hosts is considered the most efficient means of transmission, which strictly involves asexual reproduction. Nonetheless, extensive genetic diversity has been reported within the species. What is yet to be elucidated are the major drivers of such diversity, and their impact on important parasite phenotypes such as virulence. Instead of protein-encoding sequences, genome and transcriptome data were used to investigate SNPs in introns between two distinct N. caninum isolates, with reported differences in pathogenicity. Variant analysis identified 840 and 501 SNPs within intergenic regions and introns, respectively, distinctly concentrated on chromosomes VI and XI, whereas the rest of the genome was monomorphic in comparison. Gene ontologies for SNP-dense intron-containing genes included ATP binding, transmembrane transport, protein kinase activity, and transcription and translation processes. This study shows that variation in non-coding DNA is contributing to N. caninum intraspecies genetic diversity, and potentially influencing and contributing to important parasite mechanisms. Finally, we present an assembled and annotated N. caninum apicoplast genome and show that this essential organelle is highly conserved between the two isolates, and related Coccidia.

Sarcocystis falcatula-like derived from opossum in Northeastern Brazil: In vitro propagation in avian cells, molecular characterization and bioassay in birds

Most reported isolates of Sarcocystis spp. derived from Brazilian opossums (Didelphis sp.) have genetic characteristics distinct from the known species of Sarcocystis, but behave similarly as Sarcocystis falcatula, as they are infective to budgerigars. In previous studies, these Brazilian isolates, classified as Sarcocystis falcatula-like, were originated from South and Southeast regions of Brazil. In the current work, we aimed to culture and to perform multilocus sequence analysis of Sarcocystis sp. derived from a Brazilian opossum (D. aurita/D. marsupialis) that inhabited the city of Salvador, Bahia, in the Northeast of Brazil. The parasite was isolated in Vero cells, referred here as Sarco-BA1, and propagated in avian cells (DF-1). Molecular analysis of Sarco-BA1 revealed that the nucleotide sequence of the internal transcribed spacer 1 (ITS1) of the rDNA was identical to all isolates (n = 19) of Sarcocystis spp. reported in two studies from South and Southeast regions of the country. Two budgerigars were inoculated with 10 and 1000 sporocysts of Sarco-BA1, respectively, and developed acute sarcocystosis, showing that the parasite behaves like S. falcatula. It was interesting to observe that Sarco-BA1 had almost identical ITS1 and SAG sequences to all 16 isolates of S. falcatula-like recently described in Magellanic penguins (Spheniscus magellanicus) rescued on the coast of Espírito Santo state, Brazil. Our results suggest that Sarco-BA1 and S. falcatula-like may represent a single species of Sarcocystis. Propagation of the parasite in a permanent avian cell line significantly improved the yield of merozoites in cell culture. To our knowledge, this is the first molecular study and in vitro isolation of S. falcatula-like derived from Northeastern Brazil. Studies are under way to determine the infectivity of Sarco-BA1 to other animal species, as well as to investigate serological cross-reactivity among Sarco-BA1, S. neurona and related species.

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Sarcocystis falcatula-like was isolated for the first time in Northeastern Brazil.

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Its genetic pattern was similar to isolates from South and Southeastern Brazil.

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A permanent avian cell line was successfully used to propagate the parasite.

Diversity of Toxoplasma gondii strains shaped by commensal communities of small mammals

Commensal rodent species are key reservoirs for Toxoplasma gondii in the domestic environment. In rodents, different T. gondii strains show variable patterns of virulence according to host species. Toxoplasma gondii strains causing non-lethal chronic infections in local hosts will be more likely to persist in a given environment, but few studies have addressed the possible role of these interactions in shaping the T. gondii population structure. In addition, the absence of validated techniques for upstream detection of T. gondii chronic infection in wild rodents hinders exploration of this issue under natural conditions. In this study, we took advantage of an extensive survey of commensal small mammals in three coastal localities of Senegal, with a species assemblage constituted of both native African species and invasive species. We tested 828 individuals for T. gondii chronic infection using the modified agglutination test for antibody detection in serum samples and a quantitative PCR assay for detection of T. gondii DNA in brain samples. The infecting T. gondii strains were genotyped whenever possible by the analysis of 15 microsatellite markers. We found (i) a very poor concordance between molecular detection and serology in the invasive house mouse, (ii) significantly different levels of prevalence by species and (iii) the autochthonous T. gondii Africa 1 lineage strains, which are lethal for laboratory mice, only in the native African species of commensal small mammals. Overall, this study highlights the need to reconsider the use of MAT serology in natural populations of house mice and provides the first known data about T. gondii genetic diversity in invasive and native species of small mammals from Africa. In light of these results, we discuss the role of invasive and native species, with their variable adaptations to different T. gondii strains, in shaping the spatial structure of T. gondii genetic diversity in Africa.

Occurrence of tissue cyst forming coccidia in Magellanic penguins (Spheniscus magellanicus) rescued on the coast of Brazil

The main motivation for this study was to determine the occurrence of Toxoplasma gondii, a cosmopolitan widespread zoonotic parasite distribution that can infect a wide variety of mammals and birds, in Magellanic penguins (Spheniscus magellanicus) in Brazil. In recent decades there has been a significant increase in the number of penguins originating from Argentinian and Chilean Patagonia, where these birds are born, that arrive on the Brazilian coast, where many of them are stranded and rescued. Tissue samples were collected from 330 individuals surveyed from 2012–2015 at the Institute for Marine Animal Research and Rehabilitation (IPRAM) located in Cariacica, state of Espirito Santo, Brazil. Serum were collected from 145 animals surveyed in 2015 for the detection of anti-T. gondii antibodies using the Modified Agglutination Test (MAT ≥20) and 18 birds were positive, with titers of 20 (7 birds), 40 (9 birds) and 80 (2 birds). Mouse bioassay for the isolation of T. gondii was performed using tissues from 54 penguins that were also surveyed in 2015, but no isolates were obtained. DNA from tissue samples of 330 individuals was PCR amplified and sequenced to detect tissue cyst forming coccidians by using pan sarcocystids-directed primers (based on 18S rDNA). These samples were from animals surveyed in 2015 and from frozen stocked tissues from animals surveyed in the years 2012 and 2013. The positives were PCR amplified and sequenced with genus Sarcocystis-specific primers (based on internal transcribed spacer 1, RNA polymerase beta subunit coding gene, and cytochrome B coding gene) and with Sarcocystis falcatula/Sarcocystis neurona- specific primers (based on surface antigens SAG2, SAG3 and SAG4). Sixteen (3.0%) of pectoral muscle samples were positive by all the seven molecular markers and all the samples were identical to each other. Organisms close related to Sarcocystis falcatula were confirmed in all cases. This is the first report on molecular detection of infection by S. falcatula-related organisms and the first report of seropositivity for T. gondii in free-living Magellanic penguins in Brazil. Felids and didephid opossums are definitive hosts of T. gondii and S. falcatula, respectively. Where the penguins acquire the infective forms of the parasites shed by the terrestrial mammals remains to be elucidated.

Hammondia sp. oocysts shed by a Brazilian fox (Lycalopex vetulus) differ from Hammondia heydorni and Hammondia triffittae

A Brazilian fox (Lycalopex vetulus) was rescued from a highway, and 16 days after maintained in captivity, the fox shed oocysts with sizes compatible with Hammondia sp. and Neospora caninum. DNA extracted from oocysts were initially tested in two PCRs targeting the internal transcribed spacer 1 (ITS-1) of the rDNA of Hammondia heydorni and the Nc-5 gene of N. caninum. A 270-bp product was visualized in the PCR for H. heydorni. No amplification was observed for N. caninum PCR. Since ITS-1-based PCR is not sufficient to differentiate Hammondia species derived from canids, oocyst DNA was examined using multilocus sequence analysis of five genetic fragments [intron 1 of the alpha tubulin gene (intron 1), internal transcribed spaces 1 and 2 (ITS-1 and ITS-2) of the rDNA, 28S rRNA gene (D2/D3 domain), and heat shock protein 70 (Hsp70)]. The Hammondia sp. oocyst from the Brazilian fox, referred here as H-FOXBR isolate, is closely related to H. heydorni and Hammondia triffittae, but differs from these parasites in three genetic markers (alpha tubulin gene, ITS-2, and 28S rRNA). As reported by other research groups, Hammondia spp. excreted by canids are genetically diverse and may encompass additional species besides H. heydorni and H. triffittae. In this study, we confirmed that H-FOXBR has significant genetic differences in comparison to H. heydorni and H. triffittae and may represent a separate species. Further studies are needed to identify the life cycle of this parasite and to characterize the parasite stages in the intermediate and definitive hosts.

Hammondia heydorni: Oocyst shedding by dogs fed in vitro generated tissue cysts, and evaluation of cross-immunity between H. heydorni and Neospora caninum in mice

Hammondia heydorni is a coccidian parasite believed to be nonpathogenic for naturally-infected animals, but it is biologically and genetically related to Neospora caninum, a worldwide cause of abortion in cattle. The major aim of the present work was to determine whether dogs shed H. heydorni oocysts after consuming in vitro generated tissue cysts of the parasite. In addition, we investigated cross-immunity between H. heydorni and N. caninum in mice. Two dogs were fed cultured cells containing tissue cysts of H. heydorni mixed with canned dog food, and a third dog (negative control) received only non-infected cells mixed with canned food. The two dogs that consumed in vitro produced tissue cysts shed high numbers of oocysts, which were induced to sporulate and tested positive for H. heydorni by a species-specific PCR. The third uninfected dog did not shed H. heydorni oocysts in the feces. Oocysts shed by the dogs induced the formation of encysted bradyzoites of H. heydorni on KH-R cells. Nineteen BALB/c mice were employed in the cross-immunity study. Nine mice were orally inoculated with 1×10⁵ sporulated oocysts of H. heydorni and challenged with N. caninum tachyzoites 30days after infection with H. heydorni. Other ten mice, which did not receive H. heydorni oocysts, were infected with 2×10⁵N. caninum tachyzoites. Thirty days after challenging with N. caninum, all mice were euthanized and N. caninum DNA in their tissues was quantified by real time PCR. No statistically significant difference in N. caninum DNA concentrations were observed between the two groups. We concluded that in vitro generated cysts of H. heydorni are biologically active, because they induced oocyst shedding in dogs. As no cross-protection occurred in mice inoculated with H. heydorni and challenged with N. caninum, it is suspected that these parasites do not express significant numbers of homologous proteins during infection, or the immune response of BALB/c mice after H. heydorni infection was not sufficient.

Sarcocystis neurona and Neospora caninum in Brazilian opossums (Didelphis spp.): Molecular investigation and in vitro isolation of Sarcocystis spp

Sarcocystis neurona and Neospora spp. are protozoan parasites that induce neurological diseases in horses and other animal species. Opossums (Didelphis albiventris and Didelphis virginiana) are definitive hosts of S. neurona, which is the major cause of equine protozoal myeloencephalitis (EPM). Neospora caninum causes abortion in cattle and infects a wide range of animal species, while N. hughesi is known to induce neurologic disease in equids. The aims of this study were to investigate S. neurona and N. caninum in tissues from opossums in the northeastern Brazil, and to isolate Brazilian strains of Sarcocystis spp. from wild opossums for comparison with previously isolated strains. Carcasses of 39 opossums from Bahia state were available for molecular identification of Sarcocystis spp. and N. caninum in their tissues, and for sporocyst detection by intestinal scraping. In addition, Sarcocystis-like sporocysts from nine additional opossums, obtained in São Paulo state, were tested. Sarcocystis DNA was found in 16 (41%) of the 39 opossums' carcasses; N. caninum DNA was detected in tissues from three opossums. The sporocysts from the nine additional opossums from São Paulo state were tested by bioassay and induced infection in nine budgerigars, but in none of the gamma-interferon knockout mice. In vitro isolation was successful using tissues from all nine budgerigars. The isolated strains were maintained in CV-1 and Vero cells. Three of nine isolates presented contamination in cell culture and were discarded. Analysis of six isolates based on five loci showed that these parasites were genetically different from each other and also distinct from S. neurona, S. falcatula, S. lindsayi, and S. speeri. In conclusion, opossums in the studied regions were infected with N. caninum and Sarcocystis spp. and represent a potential source of infection to other animals. This is the first report of N. caninum infection in tissues from black-eared opossum (D. aurita or D. marsupialis) and white-eared opossum (D. albiventris). Brazilian opossums are probably infected by different Sarcocystis spp. distinct from S. neurona and S. falcatula, or present a high level of genetic recombination.

Molecular characterization of Sarcocystis spp. in intestine mucosal scrapings and fecal samples of Pampas fox (Lycalopex gymnocercus)

Sarcocystis spp. are obligatory intracellular protozoan parasites which can infect humans and animals. Most of Sarcocystis species were identified based on the detection of muscle cysts in different intermediate hosts (IH). Regarding to natural infection in definitive host, there are few reports which have reached to determining species of Sarcocystis. The present work was aimed to studying the occurrence of Sarcocystis spp. (oocysts and sporocysts) in mucosal scrapings of small intestine and fecal samples of one the most abundant wild canids from South America, Lycalopex gymnocercus (Pampas fox), and to identify the Sarcocystis spp. using molecular tools. A total of 131 free-living L. gymnocercus were sampled in rural areas located in several departments from Buenos Aires province, Argentina. Fecal samples from all the animals and 33 small intestines were analyzed. Fecal and mucosal scrapings samples were analyzed by sugar flotation method and once oocysts or sporocysts were detected, sedimentation was performed and DNA extracted with a commercial kit. A PCR was conducted using primers targeting a fragment of the 18S rRNA gene and the amplicons were purified and sequenced. Of the total Pampas foxes analyzed, 23 (17.6%) had Sarcocystis spp. oocysts/sporocysts in fecal and/or mucosal samples. Sarcocystis spp. sporocysts were detected in 13.0% (17/131) of fecal samples and in 39.4% (13/33) of mucosal samples by the initial sugar flotation. Twenty one L. gymnocercus samples were processed by DNA extraction and PCR. Molecular identification of Sarcocystis spp. infection was successfully achieved in 14 foxes and was distributed as follows: 4.6% S. cruzi (6/131), 3.8% Sarcocystis spp. using birds as IH (S. albifronsi and S. anasi among others, 5/131), 0.8% S. tenella (1/131) and 1.5% (2/131) with low homology (97%) with S. miescheriana. In one fecal sample with spherical oocysts, the sequencing results showed a 100% sequence identity with Hammondia heydorni. The results show that the mucosal scrapings are the eligible sample to identify prevalence and to proceed with species identification. Lycalopex gymnocercus is suggested as definitive host for S. cruzi, S. tenella and probably various Sarcocystis spp. using birds as intermediate hosts as well as for H. heydorni.

Detection of Hammondia heydorni DNA in feces collected in and around an Ohio Wildlife Conservation Center

This study aimed to identify DNA attributed to Hammondia heydorni oocysts in the feces of wild canids in and around an Ohio wildlife conservation center. Two hundred and eighty-five wild canid fecal samples were analyzed using PCR with melting curve analysis to detect coccidian DNA. Coccidia-positive samples were further subjected to H. heydorni-specific and N. caninum-specific PCR assays. Samples positive by the H. heydorni-specific assay were additionally analyzed with a PCR assay to distinguish H. heydorni from Hammondia triffittae. Coccidian DNA was detected in 51 of the 285 (17.9%) wildlife samples. H. heydorni DNA was detected in three of the coccidia-positive wildlife samples (1.1%) and N. caninum was detected in none. Determining the presence of H. heydorni in wild canids will contribute to a greater understanding of the role these hosts play in the ecology of this parasite.

Importance of serological cross-reactivity among Toxoplasma gondii, Hammondia spp., Neospora spp., Sarcocystis spp. and Besnoitia besnoiti

Toxoplasma gondii, Neospora spp., Sarcocystis spp., Hammondia spp. and Besnoitia besnoiti are genetically related cyst-forming coccidia. Serology is frequently used for the identification of T. gondii, Neospora spp. and B. besnoiti-exposed individuals. Serologic cross-reactions occur in different tests among animals infected with T. gondii and H. hammondi, as well as among animals infected by T. gondii and N. caninum. Infections caused by N. caninum and N. hughesi are almost indistinguishable by serology. Neospora caninum, B. besnoiti and Sarcocystis spp. infections in cattle show some degree of serologic cross-reactivity. Antibody cross-reactivity between Neospora spp. and H. heydorni-infected animals is suspected, but not proven to occur. We review serologic cross-reactivity among animals and/or humans infected with T. gondii, Neospora spp., Sarcocystis spp., Hammondia spp. and B. besnoiti. Emphasis is laid upon antigens and serological methods for N. caninum diagnosis which were tested for cross-reactivity with related protozoa. Species-specific antigens, as well as stage-specific proteins have been identified in some of these parasites and have promising use for diagnosis and epidemiological surveys.

Isolation and biological and molecular characterization of Neospora caninum (NC-SP1) from a naturally infected adult asymptomatic cattle (Bos taurus) in the state of São Paulo, Brazil

The biological and genetic diversity of Neospora caninum is very limited because of availability of only a few viable isolates worldwide. This study describes the isolation and biological and molecular characterization of a new viable isolate of N. caninum (NC-SP1), from a cattle in Brazil. Approximately 400 g of brain from a naturally infected adult male cattle from an abattoir was fed to a 2-month-old dog. Neospora-like oocysts were observed on day 7 post-inoculation (PI) and the duration of oocyst shedding was 14 days. The DNA obtained from oocysts was characterized molecularly and the final sequence was 99% identical to homologous sequences of N. caninum available in GenBank®. For bioassay, gerbils (Meriones unguiculatus) were orally inoculated with 10 100 and 1000 oocysts; all gerbils remained clinically normal but developed N. caninum antibodies 14 days PI. Cell culture isolation was successful using the brain homogenate from one of the gerbils and tachyzoites were observed 24 days PI. Microsatellite genotyping revealed a unique genetic profile for this new reference isolate.

Molecular investigation on the occurrence of Toxoplasma gondii oocysts in cat feces using TOX-element and ITS-1 region targets

One of the most important routes of transmission for Toxoplasma gondii infection is the ingestion of foods contaminated with cat feces containing sporulated oocysts. The diagnosis of T. gondii infection by fecal microscopy is complicated, as other similar coccidian oocysts are often present in the same fecal specimen. This study aimed to identify T. gondii oocysts in cat feces using a novel PCR technique. Feline fecal specimens (n = 254) were screened for coccidian oocysts by light microscopy using the Sheather's flotation method. PCR analysis performed on the same specimens targeted a 529 bp repeat element and internal transcribed spacer-1 (ITS-1) regions were used to confirm the presence of Toxoplasma oocysts. By light microscopy, 49/254 (19.3%) of specimens contained coccidian oocysts. PCR analysis demonstrated 2/254 (0.8%) and 17/254 (6.7%) positive results using Tox and ITS-1 primers, respectively. However, coccidian oocysts were not identified on microscopic examination of specimens that were PCR-positive by Tox primers. Coccidian oocysts were identified on microscopic examination of 6/17 (35.3%) of the PCR-positive fecal specimens using ITS-1 primers. The BLAST results of 16 ITS-1 sequences were identified as T. gondii (n = 12; 4.7%) and Hammondia hammondi (n = 4; 1.6%). There was slight agreement between the 529 bp and ITS-1 PCR results (κ = 0.148). This is the first report of the detection of Toxoplasma oocysts using PCR analysis on feline fecal specimens from Southern Thailand. The ITS-1 region has potential as an alternative marker to identify T. gondii oocysts in feline fecal specimens.

Molecular and morphologic characterization of Sarcocystis felis (Apicomplexa: Sarcocystidae) in South American wild felids from Brazil

Wild felids are thought to share parasites with domestic cats. However, little is known of the coccidian parasites of wild felids. We investigated the presence of Sarcocystis spp. in tissues of 6 species of 90 Neotropical small felids killed in road accidents in the state of Rio Grande do Sul, Brazil by using microscopic and molecular techniques. Formalin-fixed tissues from 28 felids were examined, and Sarcocystis felis-like sarcocysts were detected in 4 wild cats (2 Puma yagouaroundi and 2 Leopardus guttulus). By transmission electron microscopy, sarcocysts from a P. yagouaroundi were identical to S. felis from domestic cats in the USA. Direct sequencing of PCR amplicons resulted the unambiguous sequences of the ITS-1 region from 18 of the 31 PCR positive wild cats; 5 sequences from each P. yagouaroundi, and Leopardus geoffroyi, 4 sequences from L. guttulus, and 2 sequences from each Leopardus wiedii, and Leopardus colocolo. Sequences analysis of ITS-1 region revealed the highest identiy (97-99%) with that of previously describe isolates of S. felis from domestic cats in the USA and identified them as S. felis. Tissues of 1 Leopardus pardalis tested by PCR and histology were negative. The phylogenetic relationship indicated that S. felis is quite different to species which employ opossums as their definitive host. This is the first report of S. felis infection in small wild felids from Brazil.

Characterization of an IgG monoclonal antibody targeted to both tissue cyst and sporocyst walls of Toxoplasma gondii

Toxoplasma gondii infects animals habiting terrestrial and aquatic environments. Its oocysts and tissue cysts are important for the horizontal transmission of this parasite. The oocyst and tissue cyst walls are crucial for the ability of the parasite to persist in the environment or in animal tissues, respectively. However, the composition of these walls is not well understood. We report the generation of monoclonal antibodies directed against wall components using mice immunized with oocyst antigens of T. gondii. One monoclonal antibody (mAb) G1/19 reacted solely with T. gondii sporozoites. The respective antigen had a relative molecular weight (Mr) of 30 kDa. MAb G1/19 failed to react with sporozoites of any other coccidian parasite species tested (Hammondia hammondi, Hammondia heydorni, Cystoisospora felis, Eimeria bovis, Sarcocystis sp.). Another mAb, designated K8/15-15, recognized antigens in sporocyst walls of the parasite and in the walls of in vivo or in vitro produced tissue cysts, as demonstrated by immunofluorescence and immunoblot assays. Antigens of 80 to a high molecular weight protein of about 350 kDa Mr were recognized by this antibody using antigen extracts from sporocysts, and from in vitro or in vivo generated tissue cysts of the parasite. Tissue cyst and sporocyst walls of H. hammondi and H. heydorni, and tissue cysts of Neospora caninum were also recognized by mAb K8/15-15. Sporocyst walls of C. felis also reacted to this mAb. The cyst walls of Sarcocystis sp. and Besnoitia besnoiti were not recognized by mAb K8/15-15. Reactivity by a single mAb against T. gondii antigens in tissue cysts and sporocysts had not been reported previously. MAb K8/15-15 may be a practical tool for the identification of both cysts and sporocysts of the parasite, and may also be potentially employed in proteomic studies on the identification of new components of the cyst and sporocyst walls of T. gondii.

The detection and characterisation of Neospora /Hammondia-like oocysts from naturally infected dogs within the same urban region of Australia

This report describes the detection and molecular characterisation of Neospora/Hammondia-like oocysts from naturally infected dogs. Single faecal samples were collected from 160 individual greyhounds and multiple faecal samples were collected from 5 Labrador litters within a breeding kennel. Microscopy analysis detected Neospora/Hammondia like oocysts in 2 greyhounds and one litter of Labrador puppies. PCR protocols targeting the internal transcribed spacer region (ITS-1) and the large subunit (LSU) rDNA (D2/D3 domains) confirmed the presence of H. heydorni in both greyhounds and N. caninum in the Labrador litter. Dietary information obtained for all positive dogs indicate the source of infection was through regular exposure to a commercially obtained raw meat diet. These results report for the first time a natural infection with H. heydorni in dogs in Australia and also the first co-occurrence of N. caninum and H. heydorni in an Australian urban region.

In vitro cultivation of Hammondia heydorni: Generation of tachyzoites, stage conversion into bradyzoites, and evaluation of serologic cross-reaction with Neospora caninum

Hammondia heydorni was in vitro isolated from oocysts shed by three dogs using a finite cell line from embryonal bovine heart (KH-R). The oocysts were purified and suspended in 2% potassium dichromate or 2% sulphuric acid for sporulation for 2-5 days at room temperature. The parasites were confirmed as H. heydorni by PCR using specific primers (JS4/JS5) and by negative reaction for Neospora caninum employing the primers Np6+/Np21+. H. heydorni sporulated oocysts (1 × 10(6)) from each dog were initially treated with sodium hypochlorite. For excystation of sporozoites, oocysts from one dog were lysed by ultrasound followed by incubation with 0.75% taurocholate. Excystation of sporozoites from the other two dogs was achieved by oocyst fragmentation with glass beads with no further chemical treatment. Tachyzoites were clearly seen in the cultures at three days post inoculation (dpi). Bradyzoite conversion and cyst formation were evaluated at different time points by using a polyclonal rabbit serum against a bradyzoite-specific antigen (anti-BAG1), and a rat monoclonal antibody (mAbCC2) against a cyst wall protein. Bradyzoites were firstly detected at 7 dpi. Between 18 and 21 dpi most of cultured parasites consisted of encysted bradyzoites. The H. heydorni cysts increased in size during cultivation and reached a length of up to 135 μm. The parasite was maintained in the bovine heart cells up to 4.5months. Sera from mice and sheep experimentally infected with H. heydorni oocysts reacted with H. heydorni by IFAT, but did not cross-react with N. caninum antigens using IFAT or immunoblot. These findings suggest that serological cross-reactivity between H. heydorni and N. caninum seems to be of minor importance.

Detection of Neospora caninum-DNA in feces collected from dogs in Shenyang (China) and ITS1 phylogenetic analysis

Neospora caninum is an intracellular protozoan that infects many domestic and wild animals. Dog is known as a definitive host of N. caninum and involved in transmitting infections to intermediate hosts by shedding oocysts. To investigate the epidemiology of dog neosporosis in China, 212 dog feces specimens in Shenyang were screened by nested-PCR using Nc5 primers and confirmed by N. caninum ITS1 PCR. The positive rate of N. caninum DNA was 34.90% (74/212). There were no significant correlations in prevalence of Neospora infections between different ages and genders. N. caninum DNA positive samples were further examined by PCR using Hammondia heydorni-specific primers. 37 out of 74 N. caninum DNA positive samples were also H. heydorni DNA positive. Only Nc5 primers positive and H. heydorni primers negative samples were used for ITS1 gene sequence analysis. Sequencing results from the 37 N. caninum positive samples revealed that ITS1 gene has 96-100% similarity with N. caninum sequences deposited in Genbank. Also, the presence of a new genotype indicated genetic polymorphism of N. caninum in infected dog feces in Shenyang of China.

Molecular identification of Neospora caninum from calf/foetal brain tissue and among oocysts recovered from faeces of naturally infected dogs in southern Ethiopia

This study sought to confirm and investigate further recently published information regarding the occurrence of Neospora caninum in cattle in Ethiopia and investigate infection in dogs, the canine definitive host, in this region. Faecal samples from 383 dogs in Hawassa, Ethiopia were examined by microscopy for Neospora-like oocysts, and positive samples then analysed by a molecular approach (DNA isolation, PCR and sequencing at the ITS1 gene). Brain tissue samples from four late term aborted foetuses, one congenitally defective calf (hind leg arthrogryposis) and placental tissue from cattle in the same area were also examined by the same molecular approach. All foetal, calf and placental tissue were associated with Neospora seropositive dams. A high prevalence of Neospora-like oocysts (11.5 μm±1.5 μm diameter) was observed in faecal samples from dogs (37 positive samples; 9.7% prevalence), and in 17 of these the identification was confirmed by PCR, giving a prevalence of confirmed infection of 4.4%. N. caninum DNA was also detected in all foetal and calf brain tissue samples. Sequencing revealed only minor differences among all PCR products, whether from oocysts or from brain tissue samples. These data provide molecular evidence of the presence of N. caninum infection in both dog and cattle in this region of Ethiopia. Moreover these findings highlight the role of dogs in maintaining and spreading the infection horizontally in the study area. The high frequency of N. caninum infection in household dogs as well as farm dogs is worthy of further investigation.

First isolation of Hammondia heydorni from dogs in China

Fecal samples of 945 dogs were examined microscopically in 2 refuge facilities in China from March 2010 to November 2011. In 8 dogs, oocysts, 9-14 μm in size, were found. Their morphology was similar to those of Hammondia heydorni and Neospora caninum. Sporulated Hammondia/Neospora-like oocysts were fed to 2 dogs, 2 gerbils, 2 guinea pigs, and 2 KM mice; tissues from these inoculated animals were then fed to coccidia-free dogs to determine species susceptibility to these oocysts. Oocysts were not excreted in the feces of dogs or rodents inoculated with oocysts. However, the dogs fed the tissues of gerbils or guinea pigs that were inoculated orally with oocysts excreted fresh oocysts. Dogs fed tissues from guinea pigs inoculated with brain and muscular homogenate from guinea pigs that were fed sporulated Hammondia/Neospora-like oocysts did not excrete oocysts. These findings indicated that the oocysts from naturally infected dogs had an obligatory 2-host life cycle, with gerbils and guinea pigs as intermediate hosts. DNA isolated from these oocysts could not be amplified using N. caninum- and Toxoplasma gondii-specific primers. However, positive amplification with the H. heydorni-specific primers confirmed the presence of H. heydorni DNA in the samples. A comparison of the intron 1 sequence of the alpha tubulin gene with those from H. heydorni from dogs and H. triffittae from foxes showed that dog-derived oocysts possessed a different alpha tubulin gene. Both our dog-derived sequence and 2 previous alpha tubulin gene sequences from H. triffittae from foxes contained a 9-bp insertion relative to 3 sequences of H. heydorni from dogs. However, when the 9-bp insertion from H. triffittae sequences were compared, the 9-bp insertion in our dog-derived sequence had a nucleotide substitution. The present study, therefore, provides new evidence of genetic diversity among isolates from dogs. This is the first survey for H. heydorni in dogs from China.

Neospora caninum infection in dogs from Southern Romania: coproparasitological study and serological follow-up

Neospora caninum is an important cause of bovine abortion worldwide for which dogs are the definitive host. The present study was aimed at investigating the exposure to N. caninum infection based on lifestyle categories of dogs from southern Romania. For this purpose, randomly selected rural and urban dogs were examined for fecal N. caninum -like oocysts and were serologically tested for the presence of anti- N. caninum IgG antibodies. Of the 386 dog fecal samples, N. caninum -like oocysts were found in 19 (4.9%; 95% CI = 2.89-7.59) as follows: rural guard dogs (4/41; 9.8%), cattle farm dogs (6/118; 5.1%), and stray dogs (9/192; 4.7%) (P > 0.05). None of the 35 urban guard dogs was positive. Serum samples (n = 84) from all of the 19 N. caninum -like oocysts-positive dogs and another 65 randomly selected canines (15 cattle farm dogs, 21 rural guard dogs, and 29 strays) were tested by indirect fluorescent antibody test (IFAT). None of these dogs exhibited any symptoms of clinical neosporosis. However, IgG antibodies against N. caninum were detected in 17/84 (20.2%) (P < 0.05) serum samples. The highest prevalence was registered in cattle farm dogs (38.1%) followed by strays (18.4%) and rural guard dogs (8.0%). The seropositivity to N. caninum increased significantly with age (P < 0.05), reaching 66.7% in dogs >10 yr of age, suggesting post-natal exposure to N. caninum is the predominant mechanism of N. caninum recruitment.

Extensive production of Neospora caninum tissue cysts in a carnivorous marsupial succumbing to experimental neosporosis

Experimental infections of Sminthopsis crassicaudata, the fat-tailed dunnart, a carnivorous marsupial widely distributed throughout the arid and semi-arid zones of Australia, show that this species can act as an intermediate host for Neospora caninum. In contrast to existing models that develop relatively few N. caninum tissue cysts, dunnarts offer a new animal model in which active neosporosis is dominated by tissue cyst production. The results provide evidence for a sylvatic life cycle of N. caninum in Australia between marsupials and wild dogs. It establishes the foundation for an investigation of the impact and costs of neosporosis to wildlife.

Comparison of the ITS1 and ITS2 rDNA in Eimeria callospermophili (Apicomplexa:Eimeriidae) from sciurid rodents

The taxonomy of the coccidia has historically been morphologically based. The purpose of this study was to establish if conspecificity of isolates of Eimeria callospermophili from 4 ground-dwelling squirrel hosts (Rodentia: Sciuridae) is supported by comparison of rDNA sequence data and to examine how this species relates to eimerian species from other sciurid hosts. Eimeria callospermophili was isolated from 4 wild-caught hosts, i.e., Urocitellus elegans, Cynomys leucurus, Marmota flaviventris , and Cynomys ludovicianus . The ITS1 and ITS2 genomic rDNA sequences were PCR generated, sequenced, and analyzed. The highest intraspecific pairwise distance values of 6.0% in ITS1 and 7.1% in ITS2 were observed in C. leucurus. Interspecific pairwise distance values > 5% do not support E. callospermophili conspecificity. Generated E. callospermophili sequences were compared to Eimeria lancasterensis from Sciurus niger and Sciurus niger cinereus and to Eimeria ontarioensis from S. niger. A single, well-supported clade was formed by E. callospermophili amplicons in neighbor joining and maximum parsimony analyses. However, within the clade, there was little evidence of host or geographic structuring of the species.

Hammondia triffittae n. comb. of foxes (Vulpes spp.): biological and molecular characteristics and differentiation from Hammondia heydorni of dogs

Genomic DNAs from 3 oocyst isolates of Hammondia sp. from foxes (Vulpes vulpes and V. lagopus) and 1 oocyst isolate of Hammondia heydorni from a dog, were examined by PCR and sequence analysis of 6 loci in order to determine whether the isolates were conspecific. Consistent genetic differences were found between the fox and dog isolates, respectively, at the ITS-2 region, the lsu rRNA gene, the alpha tubulin gene and the HSP70 gene, but not at the ssu rRNA gene or ITS-1 locus. Infection experiments established that dogs were unsuitable as definitive hosts for Hammondia sp. of foxes; hence this species is regarded as separate from H. heydorni of wolf-like canids, but probably identical with Isospora triffittae (syn. Isospora triffitti) previously reported from foxes. This species has therefore been named Hammondia triffittae n. comb. Reindeer, moose, sheep, goats, foxes and rabbits may act as intermediate hosts for H. triffittae. Muscle tissues of inoculated intermediate hosts were infectious for foxes from 16 days post-infection. Oocysts of H. triffittae were subspherical, averaging 12·5×10·9 μm in size. The lsu rRNA gene and the alpha tubulin gene seem to be suitable genetic markers for differentiating between H. triffittae and H. heydorni.

Toxoplasmosis and other intestinal coccidial infections in cats and dogs

Toxoplasma gondii and related coccidians are intracellular protozoan parasites. Coccidia are obligate intracellular parasites normally found in the intestinal tract. Virtually all warm blooded animals, including humans are commonly infected with coccidians. This article reviews the diagnosis, treatment, and prevention of infections in cats and dogs related to Isospora spp, Toxoplasma gondii, and Neospora caninum. Much remains to be learned concerning the pathogenesis of clinical coccidiosis.

Australian dingoes are definitive hosts of Neospora caninum

To provide objective data on the potential role of dingoes (Canis lupus dingo) in the life cycle of Neospora caninum in Australia, the production of N. caninum oocysts by experimentally infected canids was investigated. Three dingo pups raised in captivity and three domestic dogs were fed tissue from calves infected with an Australian isolate of N. caninum, Nc-Nowra. Oocysts of N. caninum, confirmed by species-specific PCR, were shed in low numbers by one dingo pup at 12-14 days p.i. The remaining animals did not shed oocysts. Furthermore, the blood from two out of three dingoes tested positive for DNA of N. caninum using PCR tests at 14 and 28 days p.i. Oocyst shedding from the intestinal tract of a dingo demonstrates that dingoes are definitive hosts of N. caninum and horizontal transmission of N. caninum from dingoes to farm animals and wildlife may occur in Australia.

Investigation of Neospora caninum, Hammondia sp., and Toxoplasma gondii in tissues from slaughtered beef cattle in Bahia, Brazil

Neospora caninum, Hammondia sp., and Toxoplasma gondii are parasites with morphological and genetic similarities. N. caninum and T. gondii are important abortive agents of cattle and sheep, respectively, and may infect numerous animal species. Hammondia sp. is not known to induce disease in animals, but may cause confusion in the identification of closely related coccidia. The aim of this study was to investigate infection rates caused by N. caninum, Hammondia sp., and T. gondii in beef cattle using a nested PCR for Toxoplasmatinae rDNA, followed by sequencing of the PCR products. Antibodies to N. caninum and T. gondii were also investigated in the tested animals. Brains and hearts were obtained from 100 beef cattle in a slaughterhouse in Bahia. Seven samples from brain tested positive for Toxoplasmatinae DNA. No positive reactions were found in heart tissues. After sequencing of the PCR products from all positive tissues, five sequences matched with N. caninum and two matched with T. gondii. Antibodies to N. caninum and T. gondii were found in 20% and 26% of the animals, respectively. The confirmation of N. caninum and the absence of Hammondia heydorni in the tested animals is suggestive that cattle are not efficient intermediate hosts of H. heydorni; however further studies need to be performed using a greater variety of tissues and a higher sample size. The detection of T. gondii DNA in bovine tissues reinforces the potential risk of transmission of this parasite to humans and other animals through the consumption of bovine meat.

Genetic diversity amongst isolates of Neospora caninum, and the development of a multiplex assay for the detection of distinct strains

Infection with Neospora caninum is regarded as a significant cause of abortion in cattle. Despite the economic impact of this infection, relatively little is known about the biology of this parasite. In this study, mini and microsatellite DNAs were detected in the genome of N. caninum and eight loci were identified that each contained repetitive DNA which was polymorphic among different isolates of this parasite. A multiplex PCR assay was developed for the detection of genetic variation within N. caninum based on length polymorphism associated with three different repetitive markers. The utility of the multiplex PCR was demonstrated in that it was able to distinguish amongst strains of N. caninum used as either vaccine or challenge strains in animal vaccination experiments and that it could genotype N. caninum associated with naturally acquired infections of animals. The multiplex PCR is simple, rapid, informative and sensitive and should provide a valuable tool for further studies on the epidemiology of N. caninum in different host species.

Atypical Toxoplasma gondii genotypes identified in oocysts shed by cats in Germany

A total of 18,259 feline faecal samples from cats in Germany were collected and analysed for the presence of Toxoplasma gondii oocysts between June 2007 and December 2008. The proportion of T. gondii-positive samples collected between January and June was significantly lower than between July and December. The age of cats shedding T. gondii oocysts was not significantly different from the age of negative control cats. Forty-six T. gondii-positive samples were genetically characterised using nine PCR-restriction fragment length polymorphism (RFLP) markers which included newSAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico. In addition, 22 isolates that had already been partially characterised in a previous study were further typed using PCR-RFLP markers c22-8, c29-2, L358, PK1 and Apico. Genotyping of the 68 isolates revealed that the majority of T. gondii isolates (n=54) had Type II patterns at all loci but displayed a Type I pattern at the Apico locus. Three isolates displayed Type II patterns at all loci, including the Apico locus. In addition, we detected one isolate with clonal Type III patterns at all loci and three isolates with atypical and mixed genotypes. Seven isolates could not be fully genotyped. One of those isolates displayed alleles of both Types I and II at the Apico locus. To our knowledge this is the first description of the presence of T. gondii genotypes different from the clonal Types I, II and III in the faeces of naturally infected cats.

Detection of Hammondia heydorni and related coccidia (Neospora caninum and Toxoplasma gondii) in goats slaughtered in Bahia, Brazil

Hammondia heydorni is a coccidian parasite with an obligatory two host life cycle, with dogs and foxes as definitive hosts, and a number of intermediate hosts, including goats. While infection by this parasite seems to be unassociated with any clinical signs, infection by the closely related parasites Neospora caninum and Toxoplasma gondii can result in abortion, stillbirths and low yielding in caprine herds. The aim of this work was to investigate the frequency of goats infected with H. heydorni using a nested PCR, specific to Toxoplasmatinae internal transcribed spacer 1 (ITS1) of the rDNA, followed by sequencing of the purified PCR fragments. The same molecular techniques were used to determine the frequencies of N. caninum and T. gondii-infected animals. A total frequency of 13.72% (14/102) was obtained for Toxoplasmatinae DNA in goat tissues. After sequencing the PCR products from all positive tissues, a frequency of 3.92% (4/102), 1.96% (2/102) and 7.84% (8/102) were obtained for H. heydorni, N. caninum and T. gondii, respectively. All sequences shared 98-100% identity with sequences from other strains of these coccidia present in GenBank. To the authors' knowledge, this is the first report of H. heydorni DNA in tissues from naturally infected intermediate hosts.