Dynamically expressed genes provide candidate viability biomarkers in a model coccidian

Eimeria parasites cause enteric disease in livestock and the closely related Cyclospora cayetanensis causes human disease. Oocysts of these coccidian parasites undergo maturation (sporulation) before becoming infectious. Here, we assessed transcription in maturing oocysts of Eimeria acervulina, a widespread chicken parasite, predicted gene functions, and determined which of these genes also occur in C. cayetanensis. RNA-Sequencing yielded ~2 billion paired-end reads, 92% of which mapped to the E. acervulina genome. The ~6,900 annotated genes underwent temporally-coordinated patterns of gene expression. Fifty-three genes each contributed >1,000 transcripts per million (TPM) throughout the study interval, including cation-transporting ATPases, an oocyst wall protein, a palmitoyltransferase, membrane proteins, and hypothetical proteins. These genes were enriched for 285 gene ontology (GO) terms and 13 genes were ascribed to 17 KEGG pathways, defining housekeeping processes and functions important throughout sporulation. Expression differed in mature and immature oocysts for 40% (2,928) of all genes; of these, nearly two-thirds (1,843) increased their expression over time. Eight genes expressed most in immature oocysts, encoding proteins promoting oocyst maturation and development, were assigned to 37 GO terms and 5 KEGG pathways. Fifty-six genes underwent significant upregulation in mature oocysts, each contributing at least 1,000 TPM. Of these, 40 were annotated by 215 GO assignments and 9 were associated with 18 KEGG pathways, encoding products involved in respiration, carbon fixation, energy utilization, invasion, motility, and stress and detoxification responses. Sporulation orchestrates coordinated changes in the expression of many genes, most especially those governing metabolic activity. Establishing the long-term fate of these transcripts in sporulated oocysts and in senescent and deceased oocysts will further elucidate the biology of coccidian development, and may provide tools to assay infectiousness of parasite cohorts. Moreover, because many of these genes have homologues in C. cayetanensis, they may prove useful as biomarkers for risk.

Do All Coccidia Follow the Same Trafficking Rules?

The Coccidia are a subclass of the Apicomplexa and include several genera of protozoan parasites that cause important diseases in humans and animals, with Toxoplasma gondii becoming the ‘model organism’ for research into the coccidian molecular and cellular processes. The amenability to the cultivation of T. gondii tachyzoites and the wide availability of molecular tools for this parasite have revealed many mechanisms related to their cellular trafficking and roles of parasite secretory organelles, which are critical in parasite-host interaction. Nevertheless, the extrapolation of the T. gondii mechanisms described in tachyzoites to other coccidian parasites should be done carefully. In this review, we considered published data from Eimeria parasites, a coccidian genus comprising thousands of species whose infections have important consequences in livestock and poultry. These studies suggest that the Coccidia possess both shared and diversified mechanisms of protein trafficking and secretion potentially linked to their lifecycles. Whereas trafficking and secretion appear to be well conversed prior to and during host-cell invasion, important differences emerge once endogenous development commences. Therefore, further studies to validate the mechanisms described in T. gondii tachyzoites should be performed across a broader range of coccidians (including T. gondii sporozoites). In addition, further genus-specific research regarding important disease-causing Coccidia is needed to unveil the individual molecular mechanisms of pathogenesis related to their specific lifecycles and hosts.

Intestinal Parasite Infestation in HIV Infected Patients in Tertiary Care Center

Every year, the number of people living with HIV rises as a consequence of advanced infections and the positive effects of highly active antiretroviral therapy (HAART). Gastrointestinal involvement is common, with 90% of patients seeking treatment for gastrointestinal problems as their HIV infection progresses. Nonetheless, identifying and characterization of infectious agents is important for patient management by excluding a clinical diagnosis and determining appropriate treatment, as well as determining public healthcare policy for true pathogen prevalence and yielding epidemiological risk factors for specific infections. The aim of this study is to evaluate the prevalence of symptomatic or asymptomatic intestinal parasitic infection among HIV or AIDS patients. For this study with 80 HIV seropositive patients being recruited from various wards and the Integrated Counseling and Testing Center (ICTC) affiliated to the microbiology department. Patients with acute and chronic diarrhea with abdominal disorder were taken as symptomatic whereas patients without these clinical complaints and who came for routine investigations were taken as asymptomatic. Firstly stool samples were analyzed by macroscopically for the presence of mucus, blood, larvae, segments of tapeworm and adult worms. The consistencies of stool were also recorded such as formed, watery or soft or loose with odor and color. It was examined microscopically after macroscopically for protozoan cysts and trophozoites, helminthic ova and larvae, as wet mount preparation by saline and iodine preparation as well as formal ether concentrated. For the detection of intestinal coccidian parasites, smears were prepared from stool samples and a modified Ziel-Nelseen (MZN) stain was also performed. Stool samples with the detection of parasites were informed for treatment. The prevalence of intestinal parasite was 23.75% with asymptomatic and symptomatic groups having a prevalence of 16.98% and 37.04% respectively. Out of total patients, 56.25% were male and 43.75% were female. Among the male patients, 11 (13.75%) were positive for an intestinal parasitic infection and 8 (10%) were positive among females. The age distribution data revealed that the age group 21-40 years old had the highest number of intestinal parasites, followed by 41-60, 61-80, and 0-20 years old. The most intestinal parasites were found in the young and middle-aged patients, according to this study. Different parasites were identified as Entamoeba histolytica, Taenia species, Ascaris lumbricoides, Cryptosporidium parvum and Isospora with one protozoan, two coccidian parasites and two helminthes. The most common parasite was Taenia species 6 (7.5%) followed by Entamoeba histolytica 5 (6.3%) and Cryptosporidium parvum 5 (6.3%). Intestinal parasitic infection is not uncommon in HIV seropositive patients. This study underscores the need for early diagnosis and treatment of these intestinal parasites in both symptomatic and asymptomatic HIV patients.

Management and Control of Eimeria Infection in Goats

Coccidian parasites of the genus Eimeira cause coccidiosis in farm animals, which develop in both the small and the large intestines. Coccidiosis is a major economic concern in many livestock, especially in young animals, as a result of losses caused by clinical infection (diarrhea) and subclinical (poor weight gain in particular) and the required treatment costs. Herein, we summarize geographical distribution of Eimeria parasites, their life cycle, pathogenesis, clinical signs, economic losses due to coccidiosis, diagnosis, recent information on control and prevention, and anticoccidial drugs for Eimeria infection in goats. With regard to poverty alleviation in most developing agricultural countries, it is important to maintain and develop goat-related industries. Proper management should be used to prevent losses and reduce the productivity from coccidiosis in young animals by: reducing the level of environmental contamination by infectious oocysts; minimizing stress; and avoiding overcrowding.

Toxoplasma TgATG9 is critical for autophagy and long-term persistence in tissue cysts

Many of the world's warm-blooded species are chronically infected with Toxoplasma gondii tissue cysts, including an estimated one third of the global human population. The cellular processes that permit long-term persistence within the cyst are largely unknown for T. gondii and related coccidian parasites that impact human and animal health. Herein we show that genetic ablation of TgATG9 substantially reduces canonical autophagy and compromises bradyzoite viability. Transmission electron microscopy revealed numerous structural abnormalities occurring in ∆atg9 bradyzoites. Intriguingly, abnormal mitochondrial networks were observed in TgATG9-deficient bradyzoites, some of which contained numerous different cytoplasmic components and organelles. ∆atg9 bradyzoite fitness was drastically compromised in vitro and in mice, with very few brain cysts identified in mice 5 weeks post-infection. Taken together, our data suggests that TgATG9, and by extension autophagy, is critical for cellular homeostasis in bradyzoites and is necessary for long-term persistence within the cyst of this coccidian parasite.

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.

Molecular Analysis Revealed 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 (ITS-1) 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, which are closely related to B. darlingi or B. darlingi-like parasites (B. neotomofelis, B. oryctofelisi, B. akodoni or B. jellisoni). Related but not closely related to these species 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 showed also 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 a prey species of the cheetah may act as intermediate hosts.

Coccidian parasites in the endangered Forest Musk Deer (Moschus berezovskii) in China, with the description of six new species of Eimeria (Apicomplexa: Eimeriidae)

We examined 674 fresh fecal samples from forest musk deer (Moschus berezovskii Flerov) in Sichuan and Shaanxi Provinces, China, for coccidian oocysts and 65% were infected with Eimeria spp. Previously, only four Eimeria species were known from Moschus spp. Here we describe six new Eimeria species. Eimeria aquae n. sp., in 38% deer, has ovoidal oocysts, 32.0 × 23.0 μm, micropyle (M) and scattered polar granules (PGs) of various sizes are present, sometimes oocyst residuum (OR) is present; ovoidal sporocysts, 14.1 × 7.5 μm, with Stieda body (SB) and sporocyst residuum (SR). Eimeria dolichocystis n. sp., in 11% deer; cylindroidal oocysts, 36.6 × 18.9, with a M, 1 PG and OR; ovoidal sporocysts, 13.9 × 7.7, with SB and SR. Eimeria fengxianensis n. sp., in 7% deer; ovoidal oocysts, 36.3 × 25.2, a M and PGs present but OR absent; ovoidal sporocysts, 13.9 × 7.3, with SB and SR. Eimeria helini n. sp. in 24% deer; subspheroidal oocysts, 27.0 × 24.1, OR and PGs often present, but M absent; ovoidal sporocysts, 13.5 × 7.7, with SB and SR. Eimeria kaii n. sp. in 26% deer; ovoidal oocysts, 33.2 × 20.7, M and PGs present, but OR absent; ovoidal sporocysts, 14.4 × 7.5, with SB and SR. Eimeria oocylindrica n. sp., in 17% deer; cylindroidal oocysts, 36.0 × 21.4, M and 1-2 PGs present but OR absent; ovoidal sporocysts, 13.8 × 7.7, with SB and SR. Eimeria dujiangyanensis n. nom. is proposed to replace E. moschus Sha, Zhang, Cai, Wang & Liu, 1994, a junior homonym of E. moschus Matschoulsky, 1947.

Comparisons of the Sexual Cycles for the Coccidian Parasites Eimeria and Toxoplasma

Toxoplasma gondii and Eimeria spp. are widely prevalent Coccidian parasites that undergo sexual reproduction during their life cycle. T. gondii can infect any warm-blooded animal in its asexual cycle; however, its sexual cycle is restricted to felines. Eimeria spp. are usually restricted to one host species, and their whole life cycle is completed within this same host. The literature reviewed in this article comprises the recent findings regarding the unique biology of the sexual development of T. gondii and Eimeria spp. The molecular basis of sex in these pathogens has been significantly unraveled by new findings in parasite differentiation along with transcriptional analysis of T. gondii and Eimeria spp. pre-sexual and sexual stages. Focusing on the metabolic networks, analysis of these transcriptome datasets shows enrichment for several different metabolic pathways. Transcripts for glycolysis enzymes are consistently more abundant in T. gondii cat infection stages than the asexual tachyzoite stage and Eimeria spp. merozoite and gamete stages compared to sporozoites. Recent breakthroughs in host-pathogen interaction and host restriction have significantly expanded the understating of the unique biology of these pathogens. This review aims to critically explore advances in the sexual cycle of Coccidia parasites with the ultimate goal of comparing and analyzing the sexual cycle of Eimeria spp. and T. gondii.