The first molecular investigation of Besnoitia besnoiti infections among cattle in Mosul, Iraq.

BACKGROUND: Bovine besnoitiosis (elephant skin disease) caused by Besnoitia besnoiti is a costly endemic disease in the Middle East, Asia, and tropical and subtropical Africa and is also emerging as a significant problem in Europe. This study is aimed at determining the prevalence of B. besnoiti in blood and skin biopsies of cattle as well as evaluating the risk factors associated with the infection among cattle in Mosul, Iraq. METHODS AND RESULTS: To achieve this aim, four hundred and sixty apparently healthy cattle of different breeds, ages, and sexes were sampled from seven different locations in Mosul, Iraq. Blood and skin biopsies were carefully collected from each cattle, and these samples were subjected to molecular analysis. The detection of B. besnoiti was molecularly confirmed by the presence of 231 bp of ITS-1 in the rDNA gene of the protozoan. Besnoitia besnoiti DNA was present in 74 (16.09%; 95% CI = 13.01-19.72) and 49 (10.65%; 95% CI = 8.15-13.80) of the blood and skin biopsies, respectively, that were analyzed. Age, breed, and sex were significantly (p < 0.05) associated with the occurrence of B. besnoiti among cattle in the study area. CONCLUSIONS: Findings from this study will serve as baseline data in the epidemiology, prevention, and control of the protozoan among cattle in Iraq.

Morphological and molecular biology identification of Cystoisospora sp. in the blue fox, Alopex lagopus (Linnaeus, 1758).

To investigate the prevalence and molecular characteristics of Cystoisospora sp. in blue fox (Alopex lagopus), Sheather's sugar floatation method was conducted to detect coccidia in 423 fresh fecal samples randomly collected from blue fox farms from three cities in China. The overall prevalence of coccidia was 1.4% (6/423), and three Cystoisospora sp. (Cystoisospora fennechi, Cystoisospora sp. I and Cystoisospora vulpina) were identified by their morphological characteristics. The 18S ribosomal RNA (rRNA) and cytochrome c oxidase subunit I (COI) locus sequences were sequenced for molecular biological identification, homology comparison, and phylogenetic analysis of Cystoisospora sp. by single-oocyst selection technology and multi-locus-nested PCR amplification. At the 18S rRNA and COI loci, C. vulpina had 99.48% and 99.59% homology, respectively, with Cystoisospora canis and Cystoisospora ohioensis from canines. Phylogenetic analysis indicated that C. vulpina was clustered in a clade with Cystoisospora sp. from Canidae, which the relatives are consistent with the hosts. To our knowledge, this is the first report on molecular identification and evolutionary analysis of C. vulpina at two different loci.

Progression of asexual to sexual stages of Cystoisospora suis in a host cell-free environment as a model for Coccidia.

Coccidia display a characteristic life cycle, where the parasites switch between asexual and sexual development, resulting in an environmental stage, the oocyst. The entero-pathogenic Cystoisospora suis, a coccidian parasite of swine and close relative to Toxoplasma gondii, undergoes development in one host-cycle. Despite the well-described intracellular development of Coccidia, the C. suis life cycle can progress in an in vitro, host cell-free system after initial intracellular development of merozoites. A novel host cell-free cultivation method was developed by transferring purified merozoites from cell culture supernatant (dpi 6) to culture medium and incubating them for 5 days to induce their progression to sexually differentiated stages. The development of sexual stages in the absence of host cells was verified by morphological studies, flow cytometry and the transcription analysis of three genes linked to sexual stages (HAP2, OWP and TyRP). The host cell-free culture permits the sexual development (and with this, the complete life cycle progression from sporozoites to oocysts) of C. suis in vitro and provides a new tool for detailed research on the development of C. suis and possibly other Coccidia. This will also be useful for the evaluation of novel drug or vaccine targets in these parasites.

Besnoitiosis in donkeys: an emerging parasitic disease of equids in Italy.

Besnoitiosis is an emerging parasitic disease of equids. Italy is one of the few European countries where the circulation of Besnoitia spp. antibodies was demonstrated. In this study, a case of clinical besnoitiosis in two donkeys in northern Italy is reported. The two animals were clinically examined. Serum and blood samples were analyzed for the detection of Besnoitia spp. antibodies and for hematology, biochemistry, and enzyme activity, respectively. ITS-1 PCR and sequencing were carried out on DNA extracted from skin biopsies. Clinical examination revealed numerous scleral pearls in eyes of both animals; alopecia and hyperkeratosis with skin nodules in the region of the neck, hind leg, and on the pinnae were detected. No cysts were evidenced by endoscopy in respiratory and genital tracts. Both animals resulted seropositive to Besnoitia spp. antibodies by Western Blot. Hematology evidenced light anemia, leukocytosis with eosinophilia, and lymphocytosis; biochemistry and enzyme activity revealed hypoalbuminemia with decreased albumin/globulin ratio and elevated alkaline phosphatase values. Parasitic DNA extracted from skin biopsies of both donkeys demonstrated a homology of 100% with Besnoitia spp. This first clinical case of besnoitiosis in two donkeys in Italy both confirms the circulation of Besnoitia spp. in Italian equids and demonstrates that the distribution area of equine besnoitiosis in Europe could be wider than expected. Further studies are needed to infer its relevance, in relation to seroprevalence and clinical disease, and to identify the species of Besnoitia infecting donkeys. Besnoitiosis may be a neglected disease of donkeys in Europe: an early and accurate diagnosis is fundamental to implement adequate control measures to prevent a "silent" spread of Besnoitia spp. infection in equids populations.

Morphological and molecular characterization of Cystoisospora yuensis n. sp. and Cystoisospora rastegaievae (Protozoa: Eimeriidae) in amur hedgehogs, Erinaceus amurensis (Schrenk, 1859).

Twenty-four fecal samples were collected from captive amur hedgehogs (Erinaceus amurensis) in Zhengzhou, China. Based on morphological and molecular analysis, the overall prevalence of Cystoisospora was 62.5% (15/24). These samples contained two types of coccidian oocysts, including C. rastegaievae (50.0%, 12/24) and a new species named C. yuensis n. sp. (12.5%, 3/24). Sporulated oocysts (n = 30) of C. yuensis n. sp. are ovoid, (20.6 ± 1.4) µm × (20.9 ± 0.9) µm, with a shape index (length/width) of 1.0 and a smooth and bi-layered oocyst wall, 1.3 µm thick (outer layer 0.8 µm, inner 0.5 µm). A polar granule is present, but micropyle cap, micropyle, and oocyst residuum are absent. The sporocysts are ovoid-shaped, (9.3 ± 0.6) µm × (8.5 ± 1.1) µm, with a shape index (length/width) of 1.1. Stieda, substieda bodies, and refractile bodies are absent. Residuum is scattered and distributed around the entire sporocysts. At the 18S rRNA locus, C. yuensis n. sp. exhibited the highest identity to C. timoni (99.3%) from a slender-tailed meerkat. It has 98.0% identity at the 28S rRNA locus and 99.3% at the ITS locus. Based on morphological and molecular data, this isolate is a new species of Cystoisospora. Additionally, we have provided data on the prevalence of C. rastegaievae in China and sequences of the 18S rRNS, 28S rRNA, and ITS loci.

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.

Bovine besnoitiosis in an endemically infected dairy cattle herd in Italy: serological and clinical observations, risk factors, and effects on reproductive and productive performances.

Bovine besnoitiosis (Besnoitia besnoiti) is an emerging parasitic disease of cattle in Europe. This study reports a case of bovine besnoitiosis in a dairy farm housing 217 cattle in Italy. A serological screening was performed on the whole herd using the recommended approach of ELISA and confirmatory Western Blot. Seropositive animals were clinically examined to reveal symptoms and lesions of besnoitiosis. Risk factors and the effects of the parasite infection on reproductive and productive performances were evaluated. Histopathology and molecular analyses on tissues from a slaughtered cow affected by the chronic phase of the disease were carried out. An overall seroprevalence of 23.5%, which increased up to 43.5% considering only cows, was recorded. Clinical examination of 33 of the seropositive cows evidenced the presence of tissue cysts in at least one of the typical localizations (sclera, vulva, or skin) in 25 animals. Statistical analysis did not evidence any significative impact of the parasite infection on herd efficiency; however, a decrease of productive parameters was recorded in cows showing cutaneous cysts. Concerning the chronically affected cow, histopathology revealed B. besnoiti tissue cysts in the skin of the neck, rump, hind legs, eyelid and vulva, in the muzzle, in mucosal membranes of the upper respiratory tract, and in the lungs. Parasite DNA was detected also in masseter muscles, tonsils, mediastinal lymph nodes, liver, cardiac muscle, aorta wall, ovaries, uterus, and vulva. Bovine besnoitiosis continues to spread in the Italian cattle population. Breeders and veterinarians should be aware of this parasitic disease, and control programs should be developed based on surveillance through a diagnostic procedure including both clinical examination and laboratory tests.

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.

Characterization of tabanid flies (Diptera: Tabanidae) in South Africa and Zambia and detection of protozoan parasites they are harbouring.

Tabanids are haematophagous flies feeding on livestock and wildlife. In the absence of information on the relationship of tabanid flies and protozoan parasites in South Africa and Zambia, the current study was aimed at characterizing tabanid flies collected in these two countries as well as detecting protozoan parasites they are harbouring. A total of 527 tabanid flies were collected whereby 70·2% were from South Africa and 29·8% were from Zambia. Morphological analysis revealed a total of five different genera collected from the sampled areas namely: Ancala, Atylotus, Haematopota, Philoliche and Tabanus. DNA extracted from South African Tabanus par and Tabanus taeniola tested positive for the presence of Trypanosoma congolense (Savannah) and Trypanosoma theileri whilst one member from T. par was positive for Trypanosoma brucei species. DNA extracted from Zambian tabanid flies tested positive for the presence of Besnoitia species at 1·27% (2/157), Babesia bigemina 5·73% (9/157), Theileria parva 30·11% (30/157) and 9·82% (14/157) for Trypanosoma evansi. This study is the first to report on relationship of Babesia and Theileria parasites with tabanid flies. Further investigations are required to determine the role of tabanids in transmission of the detected protozoan parasites in livestock and wildlife in South Africa and Zambia.

Genotypic Identification of Cystoisospora in Immunocompromised Patients Using Tm-Variation Analysis.

Cystoisospora is responsible for morbidity in immunocompromised patients. PCR is sensitive for diagnosing Cystoisospora; however, it needs reevaluation for differential molecular diagnosis of cystoisosporiasis. We aimed at evaluating melting curve analysis (MCA) after real-time PCR (qPCR) in diagnosis and genotyping of Cystoisospora as an alternative to conventional PCR. We included 293 diarrheic stool samples of patients attending the Department of Clinical Oncology and Nuclear Medicine of Cairo University Hospitals, Egypt. Samples were subjected to microscopy, nested PCR (nPCR), and qPCR targeting the internal transcribed spacer 2 region (ITS2) of the ribosomal RNA (r RNA) gene followed by melting temperatures (Tms) analysis and comparing the results to PCR-RFLP banding patterns. Using microscopy and ITS2-nPCR, 3.1% and 5.8% of cases were Cystoisospora positive, respectively, while 10.9% were positive using qPCR. Genotyping of Cystoisospora by qPCR-MCA revealed 2 genotypes. These genotypes matched with 2 distinct melting peaks with specified Tms at 85.8°C and 88.6°C, which indicated genetic variation among Cystoisospora isolates in Egypt. Genotype II proved to be more prevalent (65.6%). HIV-related Kaposi sarcoma and leukemic patients harbored both genotypes with a tendency to genotype II. Genotype I was more prevalent in lymphomas and mammary gland tumors while colorectal and hepatocellular tumors harbored genotype II suggesting that this genotype might be responsible for the development of cystoisosporiasis in immunocompromised patients. Direct reliable identification and differentiation of Cystoisospora species could be established using qPCR-Tms analysis which is useful for rapid detection and screening of Cystoisospora genotypes principally in high risk groups.

Chronic Cystoisospora belli infection in an immunocompetent Myanmar refugee - microscopy is not sensitive enough.

BACKGROUND: Cystoisosporiasis is an opportunistic infection seen more commonly in patients with acquired immunodeficiency syndrome. Although uncommon, Cystoisospora infection can occur in immunocompetent individuals but tend to be benign and self-limiting. Chronic infection however, has been described but diagnosis can often be challenging and requires a high clinical index of suspicion. CASE PRESENTATION: We present a case of delayed diagnosis of Cystoisospora belli (C. belli) in an immunocompetent 28-year-old refugee from Myanmar. She had a history of chronic diarrhea where exhaustive investigations over many years failed to reveal a diagnosis. Cystoisospora belli cysts were finally detected in stool 4 years after investigation commenced, and PCR testing on stored colon biopsies amplified a molecular product with 99 % sequence homology to C. belli. The patient improved promptly with trimethoprim-sulfamethoxazole treatment. CONCLUSION: In the appropriate clinical context we suggest molecular testing for C. belli or an empirical therapeutic trial.

Hammondia hammondi, an avirulent relative of Toxoplasma gondii, has functional orthologs of known T. gondii virulence genes.

Toxoplasma gondii is a ubiquitous protozoan parasite capable of infecting all warm-blooded animals, including humans. Its closest extant relative, Hammondia hammondi, has never been found to infect humans and, in contrast to T. gondii, is highly attenuated in mice. To better understand the genetic bases for these phenotypic differences, we sequenced the genome of a H. hammondi isolate (HhCatGer041) and found the genomic synteny between H. hammondi and T. gondii to be >95%. We used this genome to determine the H. hammondi primary sequence of two major T. gondii mouse virulence genes, TgROP5 and TgROP18. When we expressed these genes in T. gondii, we found that H. hammondi orthologs of TgROP5 and TgROP18 were functional. Similar to T. gondii, the HhROP5 locus is expanded, and two distinct HhROP5 paralogs increased the virulence of a T. gondii TgROP5 knockout strain. We also identified a 107 base pair promoter region, absent only in type III TgROP18, which is necessary for TgROP18 expression. This result indicates that the ROP18 promoter was active in the most recent common ancestor of these two species and that it was subsequently inactivated in progenitors of the type III lineage. Overall, these data suggest that the virulence differences between these species are not solely due to the functionality of these key virulence factors. This study provides evidence that other mechanisms, such as differences in gene expression or the lack of currently uncharacterized virulence factors, may underlie the phenotypic differences between these species.

Characterization of an outbreak of emerging bovine besnoitiosis in southwestern Spain.

Bovine besnoitiosis is an emerging disease in Europe, presenting quick spread toward central and southern Spain. Characterization of an outbreak in a free-ranging Limousin and Avileña beef cattle herd from southwestern Spain territories is attempted. Serological survey in the herd revealed increase of number of infected animals, from 34.3 % on first diagnoses/exams on December 2013 to 42.5 % in the second on April 2014. Blood analysis and serum biochemistry showed important alterations like leukocytosis (+33.2 % of mean value), with lymphocytosis (+205.3 %) and increase of LDH (+25.1 %), associated with tissue damage. Clinical cases were only observed in Limousin animals. Along with typical lesions of acute and chronic besnoitiosis, inflammatory and degenerative processes and parasitic cysts were present in the corpus cavernosum and the corpus spongiosum of penis. By using polymerase chain reaction (PCR) sequencing of 18S rDNA, Besnoitia besnoiti was confirmed as causative agent; microsatellite sequence analyses showed the homology of isolates with previously studied strains.

Epidemiologic study on Besnoitia besnoiti infection in dairy herds in Jordan.

Besnoitia besnoiti is an apicomplexan parasite and the causative agent of bovine besnoitiosis which is considered as a re-emergent disease in Europe. A cross-sectional serological study was conducted to determine the seroprevalence and to identify risk factors associated with B. besnoiti infection in 68 dairy herds (n = 806 cows) in Jordan during the period from January to June 2007 and the spring of 2014. Data regarding herd's management was obtained by filling questionnaires through personal interviews with farmers. An indirect ELISA test was used to detect antibodies against B. besnoiti. Chi-square analysis and multivariable logistic regression model were used to identify risk factors associated with seropositivity to B. besnoiti. At the individual cow and herd level, the true prevalence of seropositive animals was 6 and 28.7 %, respectively. Cows between 2 and 6 years of age had significantly higher seroprevalence of B. besnoiti than other age groups. The highest seroprevalence of B. besnoiti was found in Zarqa and Irbid governorates. Multivariable logistic regression model identified that exchanging visits by farm workers to neighboring farms as a risk factor for seropositivity to B. besnoiti, while smaller herd size and twice a day farm cleaning using sweeping and water hosing were identified as protective factors. This is the first study that investigated the seroprevalence of B. besnoiti infection in dairy herds in Jordan. Further studies are warranted to explore the clinical manifestation of B. besnoiti infection as well as to identify the possible presence of other Besnoitia species and definitive hosts for the parasite.

Dynamics of Besnoitia besnoiti infection in cattle.

Bovine besnoitiosis is caused by the cyst-forming apicomplexan parasite Besnoitia besnoiti. This disease progresses in two sequential phases: a febrile acute phase with oedemas and respiratory disorders, and a chronic phase characterized by the presence of subcutaneous tissue cysts and skin lesions. Serious consequences of the infection are poor body condition, sterility in bulls and eventual death. The role of host/parasite-dependent factors, which play a major role in the pathogenesis of the disease, is not yet fully elucidated. Isolate/strain virulence, parasite stage, dose and the route of parasite inoculation were studied under different experimental conditions, which make it difficult to compare the results. Data on host-dependent factors obtained from naturally infected cattle showed that (i) the seroprevalence of infection is similar in both sexes; (ii) seropositivity increases with age; (iii) both beef and dairy cattle are susceptible to the infection; and (iv) the cell-mediated immune response is likely to play a major role because a T cell response has been observed around several tissue cysts. Whether colostral antibodies are protective and to what extent the humoral immune response might reflect the disease/protection status require further research. Thus, a well-established experimental bovine model could help to clarify these important questions. The dynamics of B. besnoiti infection in cattle and available knowledge on relevant factors in the pathogenesis of the infection are reviewed in the present work.

No detection of Besnoitia besnoiti DNA in the semen of chronically infected bulls.

Bovine besnoitiosis is a chronic and debilitating disease observed in many European countries that may cause important economic losses in cattle. The recent widespread of the parasite in Europe had led the European Food Safety Authority to declare bovine besnoitiosis as a re-emerging disease in Europe. Many aspects of the epidemiology of bovine besnoitiosis such as the main routes of transmission are still unclear and need to be further studied. Among the different hypotheses, a sexual transmission has not yet been investigated. Therefore, the aim of this study was to evaluate the presence of Besnoitia besnoiti DNA in the semen of naturally infected bulls by using a highly sensitive method (real-time qPCR). Both pre-sperm and sperm fractions of 40 bulls, including seronegative (n = 11), seropositive subclinically (n = 17), and seropositive clinically (n = 12) infected animals, were collected by electroejaculation and analyzed by real-time qPCR. No B. besnoiti DNA was detected in 27 pre-sperm and 28 sperm fractions of the 40 examined bulls, suggesting that the transmission of B. besnoiti infection by the semen of chronically infected bulls is very unlikely.

Characterisation of full-length mitochondrial copies and partial nuclear copies (numts) of the cytochrome b and cytochrome c oxidase subunit I genes of Toxoplasma gondii, Neospora caninum, Hammondia heydorni and Hammondia triffittae (Apicomplexa: Sarcocystidae).

Genomic DNA was extracted from three oocyst isolates of Hammondia triffittae from foxes and two oocyst isolates of Hammondia heydorni from dogs, as well as from cell culture-derived tachyzoites of Toxoplasma gondii (RH strain) and Neospora caninum (NC-Liverpool strain), and examined by PCR with primers targeting the cytochrome b (cytb) and the cytochrome c oxidase subunit I (cox1) genes in order to characterise both genes and, if possible, the remainder of the mitochondrial genome of these species. Several primers were designed and used in various combinations to amplify regions within and between both genes and to determine gene order. When certain forward primers targeting cytb were used in combination with certain reverse primers targeting cox1, two overlapping sequences were obtained for each species and isolate studied, which showed that a full-length copy of cytb was followed 36-37 bp downstream by a full-length copy of cox1, and these sequences are believed to represent the true mitochondrial genes and the gene order in the mitochondrial genome of the four species examined. The cytb of T. gondii, N. caninum, H. heydorni and H. triffittae comprised a total of 1,080 bp (359 amino acids) and used ATG and TAA as start and stop codon, respectively. The cox1 of these species also used TAA as stop codon, whereas the most likely start codon was ATG, resulting in a gene comprising 1,491 bp (496 amino acids). Pair-wise sequence comparisons based on either cytb or cox1 clearly separated T. gondii from N. caninum and both of these species from the two Hammondia species, whereas the latter two species were 100 % identical at cytb and shared 99.3 % identity at cox1. Phylogenetic analyses using the maximum-likelihood method confirmed these findings and placed T. gondii in a clade separate from the three other species and all four Toxoplasmatinae in a sister clade to Eimeria spp. PCR with other primers and/or primer pairs than those used to obtain the full-length mitochondrial genes yielded several types of about 1-1.5 kb long sequences, which comprised stretches of the primer-targeted genes at both ends and an intervening non-coding sequence of various length and composition. Thus, portions of cytb could be found both upstream and downstream from portions of cox1 and portions of the same gene could be found adjacent to each other (cytb→cox1; cox1→cytb; cytb→cytb; cox1→cox1). Sequence comparisons revealed that some of these gene fragments were truncated genes, whereas others included the putative start or stop codon of the full-length mitochondrial genes. From the nature of the gene fragments and/or their flanking sequences, they are assumed to be located on the chromosomes of the nuclear genome and to represent nuclear mitochondrial DNA segments (numts) or pseudogenes. In the four species examined, there were no nucleotide differences between the full-length mitochondrial copies of cytb and cox1 and their various incomplete nuclear counterparts. With a few exceptions, identical numt types and closely similar flanking sequences were obtained for all four species, which would indicate that the original transfer of these mitochondrial genes to the nuclear genome and/or the majority of any subsequent rearrangements of these gene fragments within the nuclear genome happened before the four species diverged. Yet, there were species-specific differences in the nucleotide composition of the nuclear gene fragments, identical to the differences in the mitochondrial genes, which would indicate that the incomplete nuclear copies of cytb and cox1 have been continuously updated during evolution to conform to their mitochondrial parent genes. The PCR-based findings of numts were further supported by Basic Local Alignment Search Tool (BLAST) searches against genome sequences of T. gondii and N. caninum using the concatenated mitochondrial cytb/cox1 sequences as queries. These searches revealed the presence of numerous numts of eighth distinct types in both species, with each one having a fixed starting and end point with respect to the nucleotide positions in the full-length mitochondrial genes. Four numt types were completely homologous between both species, whereas four other types differed with respect to their end point and/or the absence/presence of a 96-bp deletion. Each starting and end point was associated with a unique 100-200-bp long flanking sequence, which further revealed the presence of numts. For both species, the numt types and their various arrangements with respect to each other were identical or similar to those obtained by PCR in all four species examined. None of the identified numts covered a full-length gene, but together, the various numts covered the entire mitochondrial cytb and cox1 genes in an overlapping manner. In addition, they were fairly closely spaced on the chromosomes, and these features may explain why the nuclear copies were preferentially amplified to the exclusion of the true mitochondrial genes with most primers and primer pairs used in the present study. The possibility of a similar high prevalence of numts occurring in the nuclear genome of dinoflagellates is discussed.

Transcriptional changes associated with apoptosis and type I IFN underlie the early interaction between Besnoitia besnoiti tachyzoites and monocyte-derived macrophages.

Besnoitia besnoiti-infected bulls may develop severe systemic clinical signs and orchitis that may ultimately cause sterility during the acute infection. Macrophages might play a relevant role in pathogenesis of the disease and the immune response raised against B. besnoiti infection. This study aimed to dissect the early interaction between B. besnoiti tachyzoites and primary bovine monocyte-derived macrophages in vitro. First, the B. besnoiti tachyzoite lytic cycle was characterized. Next, dual transcriptomic profiling of B. besnoiti tachyzoites and macrophages was conducted at early infection (4 and 8 h p.i.) by high-throughput RNA sequencing. Macrophages inoculated with heat-killed tachyzoites (MO-hkBb) and non-infected macrophages (MO) were used as controls. Besnoitia besnoiti was able to invade and proliferate in macrophages. Upon infection, macrophage activation was demonstrated by morphological and transcriptomic changes. Infected macrophages were smaller, round and lacked filopodial structures, which might be associated with a migratory phenotype demonstrated in other apicomplexan parasites. The number of differentially expressed genes (DEGs) increased substantially during infection. In B. besnoiti-infected macrophages (MO-Bb), apoptosis and mitogen-activated protein kinase (MAPK) pathways were regulated at 4 h p.i., and apoptosis was confirmed by TUNEL assay. The Herpes simplex virus 1 infection pathway was the only significantly enriched pathway in MO-Bb at 8 h p.i. Relevant DEGs of the Herpes simplex virus 1 infection (IFNα) and the apoptosis pathways (CHOP-2) were also significantly regulated in the testicular parenchyma of naturally infected bulls. Furthermore, the parasite transcriptomic analysis revealed DEGs mainly related to host cell invasion and metabolism. These results provide a deep overview of the earliest macrophage modulation by B. besnoiti that may favour parasite survival and proliferation in a specialized phagocytic immune cell. Putative parasite effectors were also identified.

Description of Sarcocystis platyrhynchosi n. sp. (Apicomplexa: Sarcocystidae) from domestic ducks Anas platyrhynchos (Anseriformes: Anatidae) in China.

BACKGROUND: Limited data are currently available on protozoan parasites of the genus Sarcocystis that infect their avian hosts within the order Anseriformes (waterfowl). To date, no Sarcocystis species has been recorded in ducks in China. METHODS: Leg muscles were sampled from 26 domestic ducks (Anas platyrhynchos) in China in 2021. Morphological characteristics of sarcocysts detected in the muscle tissue were described using light microscopy (LM) and transmission electron microscopy (TEM). Genomic DNA was extracted from single sarcocysts obtained from different ducks, and three genetic markers, 18S ribosomal DNA (18S rDNA), 28S ribosomal DNA (28S rDNA) and mitochondrial (mt) cytochrome oxidase subunit 1 (cox1), were amplified and cloned for sequence analyses. RESULTS: Sarcocysts were observed by LM in only three of the 28 samples (10.7%). These sarcocysts had a thick cyst wall with numerous brush-like villar protrusions (vps) of 3.8-4.3 µm in length (n = 30) on the cyst surface. TEM observation showed that the sarcocysts had lanceolated vps. Each vps narrowed in the stalk and contained a bundle of microtubules that extended into the ground substance. Comparisons of the new sequences with those deposited in GenBank showed that the most similar sequences were those of Sarcocystis halieti in the great cormorant Phalacrocorax carbo and European starling Sturnus vulgaris, and Sarcocystis calchasi in the domestic pigeon (Columba livia) at the 18S rDNA (99.1% identity); Sarcocystis wenzeli from the domestic chicken Gallus gallus at the 28S rDNA (95.9-96.0% identity); and Sarcocystis speeri from the opossum at the mtcox1 (98.2% identity). The new 18S rDNA, 28S rDNA and mitochondrial cox1 sequences shared up to 99.0%, 95.6% and 97.7% identity, respectively, with those of Sarcocystis spp. obtained from Anseriformes avian hosts. Phylogenetic analysis inferred from the sequences of the three genetic markers placed the organism within a group of Sarcocystis spp. obtained from avian or carnivorous intermediate hosts and avian, marsupial or carnivorous definitive hosts. Based on the morphological observation and molecular analyses, the organism found in the Chinese domestic ducks was regarded as a new species and named Sarcocystis platyrhynchosi n. sp. CONCLUSIONS: Based on morphology and sequence analyses, the microcysts diagnosed in the domestic ducks examined in this study were named as a new species. This is the first record of Sarcocystis spp. from waterfowl in China. Sarcocysts of similar morphology occur frequently in different Anseriformes birds, and the relationships among these species need to be further clarified in future studies using more molecular markers.

Inhibition of sexual stage-specific proteins results in reduced numbers of sexual stages and oocysts of Cystoisospora suis (Apicomplexa: Coccidia) in vitro.

Parasites of the order Coccidia (phylum: Alveolata, subphylum: Apicomplexa) have sophisticated life cycles that include a switch from asexual to sexual development, characterised by distinct cell types. During the development of gametes (gamogony), substantial changes occur at the cellular and subcellular levels, leading to cell fusion of micro- and microgametes, and the development of a zygote that forms a protective outer layer for environmental survival as an oocyst, the transmissible stage. Studies on the porcine coccidian Cystoisospora suis already identified changes in transcription profiles during different time points in the parasite's development and identified proteins with potential roles in the sexual development of this parasite. Here, we focus on three proteins that are possibly involved in the sexual development of C. suis. Enkurin and hapless protein 2 (HAP2) play important roles in signal transduction and gamete fusion during the fertilisation process, and oocyst wall forming protein 1 (OWP1) is a homologue of oocyst wall forming proteins of related parasites. We evaluated their locations in the different life cycle stages of C. suis and their inhibition by specific antibodies in vitro. Immunolocalization detected enkurin in merozoites and sporulated oocysts, HAP2 in merozoites and microgamonts, and OWP2 in merozoites, macrogamonts, oocysts and sporozoites. Up to 100% inhibition of the development of sexual stages and oocyst formation with purified chicken immunoglobulin IgY sera against recombinant enkurin, HAP2, and especially OWP1, were demonstrated. We conclude that the three investigated sexual stage-specific proteins constitute targets for in vivo intervention strategies to interrupt parasite development and transmission to susceptible hosts.