Oocyst Output Research Articles

Sex-determined susceptibility and differential MUC2 mRNA expression during the course of murine intestinal eimeriosis.

Parasitic diseases differ in prevalence, course, and severity between males and females. The study was designed to compare males with females for the susceptibility to Eimeria papillata infection as well as the expression of the mucin gene, MUC2. Oocysts output was detected to be more in the feces of male mice (3.5 × 10(4) ± 4000 oocysts/g feces) than in females (2 × 10(4) ± 2000 oocysts/g feces). In addition, infected males showed a significant higher number of meronts, gamonts, and developing oocysts compared to infected female mice. Moreover, E. papillata induced a marked goblet cell hypoplasia where the jejuna of infected male mice contained lower numbers of goblet cells per ten villus-crypt units compared to infected females. Also, the expression of MUC2 mRNA is found to be more expressed in infected females than males. In addition, testosterone, nitric oxide, and inducible nitric oxide synthase activities were found to be higher in infected male mice than in infected females. In general, male Swiss albino mice have been shown to be relatively more susceptible to infection with E. papilaata when compared with female mice.

Antioxidant and anticoccidial effects of garlic powder and sulfur amino acids on Eimeria-infected and uninfected broiler chickens

Summary To study the anticoccidial and antioxidant effects of garlic powder (GP) and total sulfur amino acid (TSAA) on growth performance, faecal oocyst output, oxidative stress indicators and antioxidant status markers in broiler chickens, a 2 × 2 × 2 splitplot-factorial arrangement of treatments was used. A total of 480-day-old male broiler chickens were equally assigned to two plots. Two hundred forty chickens were challenged with Eimeria oocysts species mix by oral inoculation at day 34 (infected plot) and the other half was left unchallenged. In each plot, chickens were randomly assigned to four treatments with 5 replicates of 12 birds each, and fed one of the following diets: basal diet, basal diet plus 0.5% GP, basal diet plus 50% more TSAA, basal diet plus 0.5% GP and 50% more TSAA. The results showed that inoculation with 7.5 × 10 2 oocysts of Eimeria mixed species significantly reduced growth performance (P<0.05) and increased nitric oxide (NO) and malonyldialdehyde (MDA), but did not change the hepatic activity of superoxide dismutase (SOD) and the glutathione peroxidase (GPX) activity. Growth depression and increased NO and MDA were greater in infected than uninfected birds. In the infected birds fed with the basal diet without any supplementation, NO and MDA were significantly greater (P<0.05) in comparison with other groups. Faecal oocyst output significantly decreased with the supplementation of GP and TSAA in infected birds (P<0.05). In conclusion, the supplementation of GP and 50% TSAA individually or in combination with the basal diet significantly improved ADG (P<0.05) and decreased OPG, MDA and NO. Moreover, no changes in the antioxidant enzymes were observed in birds infected with Eimeria.

Evaluation of Eimeria oocyst whole antigen vaccine and the enhancive effect of probiotic on broilers

Chicken coccidiosis has great economic impacts on poultry industry. The present study was conducted to evaluate the effect of feeding probiotic (Biopellt-s) as well as Eimeria oocyst whole antigen vaccine by subcutaneous and intraperitoneal routes on body weight gain, lesion score, oocyst output, and phagocytic activity. One-day old broiler chicks were divided into seven equal groups (50 chicks each); control negative group (C-Ve), probiotic fed group (PRO), subcutaneous vaccinated group (S/C), intraperitoneal vaccinated group (I/P), S/C plus probiotic (S/C Pro), I/P plus probiotic (I/P Pro), and positive control group (C+Ve). At four weeks, chicks challenged with 12.000 sporulated oocysts. Vaccination decreases the lesion score and the oocyst output in S/C group (9000 oocyst/gram) and in I/P group (12500 oocyst/gram) compared with positive control (43500 oocyst/gram). S/C was more effective than I/P for controlling the infection. Probiotic supplementation resulted in significant increase in body weight gain (1323 gm) compared with positive control (1026.667 gm) and phagocytic activity (22.83 %) compared with positive control (16.08 %) while the vaccination was more effective than probiotic alone. S/C vaccination with probiotic was more effective than with I/P vaccination. Therefore, this study recommends the use of S/c or I/P vaccination regimens for coccidiosis. Keywords : Chicken Coccidiosis, Eimeria Oocyst Whole Antigen Vaccine, Probiotic.

Biological characteristics of Chinese precocious strain of eimeria acervulina and its immune efficacy against different field strains.

In this study, the biologic characteristics of one experimental precocious strain of Eimeria acervulina and seven field isolates from different geographic locations in China were compared, and the immune efficacy of two precocious strains against coccidiosis in chickens was assessed to explore their potential use as coccidiosis vaccines. All the different strains were purified by single oocyst separation and their monospecificity was confirmed using E acervulina-specific PCR assays. The average sizes of E. acervulina oocysts were 18.28-20.19 X 14.09-14.79 microm and the shape indexes were from 1.28 to 1.40. The prepatent periods ranged from 93 to 115 hr, except for the Heyuan precocious strain (HYP; 75 hr). Chickens infected with Huadu field strain (GHD) produced the highest oocyst output whereas HYP induced the lowest level. When inoculated with 50,000 sporulated oocysts or more, the average weight gains of infected chickens were reduced, with apparent clinical symptoms. To assess the immunogenicity of precocious strains HYP and Baoding (BDP), birds were orally immunized and challenged with seven different field strains of E. acervulina. Body weight gain, fecal oocyst output, and gut lesion scores were compared to evaluate their vaccine potential. The results showed that the average body weight gains of chickens in all the vaccinated and challenged groups were higher than those of nonvaccinated and challenged groups. In general, oocyst shedding was reduced 34.39%-95.31% and gut lesion scores decreased 31.03%-86.21% compared with unvaccinated and challenged control chickens. In summary, this study indicated that the precocious strains of E. acervulina could induce a protective immune effect with various responses against coccidiosis caused by different field strains.

Evaluation of an experimental irradiated oocyst vaccine to protect broiler chicks against avian coccidiosis.

The current study investigates the use of irradiated oocysts to protect broiler chicks, raised on litter, from infection with multiple species of Eimeria. In order to determine the optimum radiation dose for each Eimeria species, 1-day-old chicks were immunized with oocysts of Eimeria maxima, Eimeria acervulina, or Eimeria tenella exposed to gamma radiation ranging from 0-500 Gy. The litter oocyst counts at 7 days postimmunization, and the effect on weight gain following a challenge infection, decreased with an optimum dose between 150-200 Gy. Based on this finding, broiler chicks were immunized with a mixture of E. maxima, E. acervulina, and E tenella that had been exposed to 150 or 200 Gy. This resulted in more than a 100-fold reduction in litter oocyst counts and significant protection from a challenge infection, as measured by improved weight gain and feed conversion ratio (FCR). Immunization of birds with oocysts receiving 200 Gy was less effective in providing protection from a challenge infection. An additional formulation of vaccines containing two different oocyst doses of the three species that had been irradiated with 150 Gy were evaluated in their ability to attenuate oocyst output and convey protection to challenge. Results were similar with both high and low numbers of irradiated oocysts. Immunized chicks shed less oocysts at 7 days postimmunization and were protected from negative effects of challenge infection as measured by FCR, changes in weight gain, lesion scores, and measurement of body composition. However, the level of protection was somewhat less than that achieved by immunization with nonirradiated oocysts. The overall conclusion is that an irradiated oocyst vaccine developed in this study can effectively protect chicks that are raised on litter from challenge infection with multiple species of Eimeria, comparable to vaccines with virulent or precocious strains.

Anticoccidial effects of herbal extracts on Eimeria tenella infection in broiler chickens: in vitro and in vivo study.

Safe alternative anticoccidial drug to chemical feed additives are herbal extracts, because they don't results to tissue residue and drug resistance. In order to evaluate the effects of herbal extracts to control avian coccidiosis, 180 one-day-old broiler chickens were randomly divided into nine equal groups, as follows: (1) Biarum bovei (2) Nectaroscordum tripedale( 3) Dorema aucheri (4) Cichorium intybus (5) Prangos ferulaceae (6) diclazuril (7) Artemisia absinthium (8) infected control (9) uninfected control (each contains two groups). Administration of herbal extracts and supplementation of diclazuril was began 2days before challenge and lasted for the duration of the experiment. The chicks of all the groups except uninfected control group were inoculated orally with sporulated oocysts (3×10(3) oocysts of Eimeria tenella) on the day 22 of age. The criteria employed were: body weight, feed conversion ratio, blood in feces, survival rate, lesion scoring, number of oocyst output per gram feces and histopathological changes. For histopathological evaluation, on day 12 post inoculation three birds from each group were randomly selected and humanly sacrificed. N. tripedale and diclazuril revealed better results in terms of growth performance, lesion score, extent of bloody diarrhea and oocyst count as compared to other herbal extracts. The increase in the severity of lesions was observed in groups of D. aucheri, A. absinthium, B. bovei, P. ferulaceae, C. intybus, diclazuril and N. tripedale, respectively. In conclusion, the current study showed that herbal extracts were effective in control of coccidiosis caused by the E. tenella infection.

Anticoccidial activity of aqueous extract of a wild mushroom (Ganoderma applanatum) during experimentally induced coccidial infection in broiler chicken.

Despite presence of anticoccidial drugs and vaccines in the market, coccidiosis continues to result in substantial economic losses to the poultry industry. There is wide-spread resistance to already known anticoccidial drugs. It is an infectious disease of poultry and rigorous management is required during vaccination. In addition there is possibility of drug residues in meat and other byproducts of such treated animals and consequently makes more imperative to explore and understand the role of natural products in livestock parasite management. Therefore a study was designed to evaluate the anticoccidial activity of aqueous extract of Ganoderma applanatum in broilerchicken. In-vivo anticoccidial activity of aqueous extract of G. applanatum was measured in comparison to the reference drug amprolium on the basis of oocysts per gram of faeces, weight gain and feed conversion ratio. Oocyst output was measured with the help of Mc-Masters counting technique. The results of this study established the virulence of coccidian oocysts and the effectiveness of both amprolium and aqueous extract of G. applanatum against coccidian oocysts, confirmed by the fact that treatment with aqueous extract of G. applanatum resulted in a noticeable reduction in coccidian oocysts output, leading to improved weight gain and better feed conversion ratio. The study highlighted the potential of G. applanatum as a natural source of bioactive components for controlling a protozoan parasite, which can be isolated and tested in a bioassay-guided manner and harnessed in the form of anticoccidial drugs.

Re-description of a genetically typed, single oocyst line of the turkey coccidium, Eimeria adenoeides Moore and Brown, 1951.

The Guelph strain of Eimeria adenoeides was obtained from a commercial turkey flock in Ontario, Canada, in 1985. Single oocyst derived lines of E. adenoeides were propagated, and one of them used to re-describe biological and morphological features of E. adenoeides in the turkey. Oocysts of this strain are within the lower size ranges in the original species description reported by Moore and Brown (1951); oocysts of the Guelph strain averaged 18.7 ± 1.4μm (16.7-22.5) by 14.3 ± 0.9μm (13-16.2, n = 30) with a shape index (SI) of 1.3 ± 0.1. It is possible that the original species description was based, at least in part, on a mixed culture of two or more Eimeria species. Immature first-generation meronts of E. adenoeides Guelph strain were observed histologically at 32h post-infection in the ileum and cecal neck. Early studies reported only two asexual generations suggested that first asexual cycle observed at 32h post-infection was overlooked. In the present study, three asexual generations were observed before the start of gametogony. The Guelph strain is also characterized by a prepatent period of 112h. The Guelph strain of E. adenoeides is a highly pathogenic coccidium that forms classic cecal lesions, including prominent caseous cecal cores, during moderate to severe infections. The maximum output of oocysts (1.77 × 10(7) per bird) was obtained from birds inoculated with 1 × 10(3) oocysts; maximum fecundity (1.55 × 10(5) oocyst shed per oocyst inoculated) was obtained with an inoculation of 1 × 10(2) oocysts, but fecundity dropped dramatically as the inoculation dose increased. To promote stability of the E. adenoeides species concept, neotype specimens (a parahapantotype slides series and phototype) have been designated and deposited for future reference.

Pichia pastoris expressed EtMic2 protein as a potential vaccine against chicken coccidiosis

Chicken coccidiosis caused by Eimeria species leads to tremendous economic losses to the avian industry worldwide. Identification of parasite life cycle specific antigens is a critical step in recombinant protein vaccine development against Eimeria infections. In the present study, we amplified and cloned the microneme-2 (EtMIC2) gene from Eimeria tenella wild type strain SD-01, and expressed the EtMic2 protein using Pichia pastoris and Escherichia coli expression systems, respectively. The EtMic2 proteins expressed by P. pastoris and E. coli were used as vaccines to immunize chickens and their protective efficacies were compared and evaluated. The results indicated that both P. pastoris and E. coli expressed EtMic2 proteins exhibited good immunogenicity in stimulating host immune responses and the Pichia expressed EtMic2 provided better protection than the E. coli expressed EtMic2 did by significantly increasing growth rate, inducing high specific antibody response, reducing the oocyst output and cecal lesions. Particularly, the Pichia expressed EtMic2 protein exhibited much better ability in inducing cell mediated immune response than the E. coli expressed EtMic2.

The comparative analysis of infection pattern and oocyst output in Eimeria tenella, E. maxima and E. acervulina in young broiler chicken

The comparative analysis of infection pattern and oocyst output in Eimeria tenella, E. maxima and E. acervulina in young broiler chicken

A novel recombinant BCG vaccine encoding eimeria tenella rhomboid and chicken IL-2 induces protective immunity against coccidiosis.

A novel recombinant Bacille Calmette-Guerin (rBCG) vaccine co-expressed Eimeria tenella rhomboid and cytokine chicken IL-2 (chIL-2) was constructed, and its efficacy against E. tenella challenge was observed. The rhomboid gene of E. tenella and chIL-2 gene were subcloned into integrative expression vector pMV361, producing vaccines rBCG pMV361-rho and pMV361-rho-IL2. Animal experiment via intranasal and subcutaneous route in chickens was carried out to evaluate the immune efficacy of the vaccines. The results indicated that these rBCG vaccines could obviously alleviate cacal lesions and oocyst output. Intranasal immunization with pMV361-rho and pMV361-rho-IL2 elicited better protective immunity against E. tenella than subcutaneous immunization. Splenocytes from chickens immunized with either rBCG pMV361-rho and pMV361-rho-IL2 had increased CD4+ and CD8+ cell production. Our data indicate recombinant BCG is able to impart partial protection against E. tenella challenge and co-expression of cytokine with antigen was an effective strategy to improve vaccine immunity.

The impact of grazing management on seasonal activity of gastrointestinal parasites in goats

Abstract The aim of this study was to examine the impact of grazing management and other risk factors (age, treatment practices) on seasonal activity of gastrointestinal (GI) parasites in goats. Goat flocks naturally infected with GI parasites reared on four Lithuanian farms representing different management regimes were examined during the grazing season in 2011/2012. On three farms the adult goats were grazed in different ways on open pastures (with or without supplementary feeding) or tethered. On one farm all animals were kept indoor (zero-grazing). On each farm, samples were collected at monthly intervals from 13–15 adult and 10 kids. The results showed that grazing of adult goats with feed supplementation or kept indoor, shed the lowest number of strongyle eggs when compared to those kept on pasture (P &lt; 0.05). Delayed turnout and zero-grazing significantly reduced excretion of strongyle eggs but increased the output of oocysts when compared to those grazed on set-stocked pasture together with adult goats. The most prevalent genus on all farms and in both age groups of goats were Teladorsagia spp. This study demonstrates that goats are infected with mixed species of parasites, but proportions of these parasites differed in different grazing management systems. The grazing management, age and season were all major factors that had an impact on GI parasite infection.

Effects of Artemisia annua and Foeniculum vulgare on chickens highly infected with Eimeria tenella (phylum Apicomplexa).

BackgroundIntensive poultry production systems depend on chemoprophylaxis with anticoccidial drugs to combat infection. A floor-pen study was conducted to evaluate the anticoccidial effect of Artemisia annua and Foeniculum vulgare on Eimeria tenella infection. Five experimental groups were established: negative control (untreated, unchallenged); positive control (untreated, challenged); a group medicated with 125 ppm lasalocid and challenged; a group medicated with A. annua leaf powder at 1.5% in feed and challenged; and a group treated with the mixed oils of A. annua and Foeniculum vulgare in equal parts, 7.5% in water and challenged. The effects of A. annua and oil extract of A. annua + F. vulgare on E. tenella infection were assessed by clinical signs, mortality, fecal oocyst output, faeces, lesion score, weight gain, and feed conversion.ResultsClinical signs were noticed only in three chickens from the lasalocid group, six from the A. annua group, and nine from the A. annua + F. vulgare group, but were present in 19 infected chickens from the positive control group. Bloody diarrhea was registered in only two chickens from A. annua group, but in 17 chickens from the positive control group. Mortality also occurred in the positive control group (7/20). Chickens treated with A. annua had a significant reduction in faecal oocysts (95.6%; P = 0.027) and in lesion score (56.3%; P = 0.005) when compared to the positive control. At the end of experiment, chickens treated with A. annua leaf powder had the highest body weight gain (68.2 g/day), after the negative control group, and the best feed conversion (1.85) among all experimental groups.ConclusionsOur results suggest that A. annua leaf powder (Aa-p), at 1.5% of the daily diet post-infection, can be a valuable alternative for synthetic coccidiostats, such as lasalocid.

High excretion of Cryptosporidium ubiquitum by peri-parturient goats in one flock in western France

Cryptosporidium spp. is an important agent of neonatal diarrhoea in goat kids. Little is known about its molecular characterization in adult goats. A longitudinal study was set up to identify the species excreted by adult goats around parturition. Individual faecal samples were collected from 20 pregnant adult goats between 1 and 5 years old in one flock. Samplings began 3 weeks before the estimated kidding date and were done weekly until kidding and for 2 weeks after kidding. Cryptosporidium oocysts were concentrated from 15g of faeces using a caesium chloride (CsCl) method. Oocyst output was determined using a direct immunofluorescent antibody test (IFAT). Genomic DNA was extracted from each CsCl-concentrated faecal sample positive by IFAT and submitted to a nested PCR-RFLP on the SSU rDNA gene followed by sequencing to identify the isolates at species level. According to their kidding date, goats were sampled between 4 and 8 times. Sixteen goats, out of the eighteen which kidded, were found positive at least at one sampling date. Infection was asymptomatic. Prevalence of excretion was maximal 14 days before kidding with half of the goats excreting oocysts at this date. Excretion was higher before kidding than after kidding. Unexpected levels of excretion were observed with individual oocyst excretion ranging from 6 to 2.5×105 oocysts per gram of faeces. All isolates were identified as Cryptosporidium ubiquitum.

Immunization with recombinant 3-1E protein in AbISCO®-300 adjuvant induced protective immunity against Eimeria acervulina infection in chickens

Immunostimulating complexes (ISCOMs), a kind of novel antigen presenting system, could enhance immune protection by antigen presentation. AbISCO®-300 comprising purified saponin, cholesterol and phosphatidyl choline is an effective ISCOM adjuvant. To evaluate the immune protection of recombinant 3-1E protein against Eimeria acervulina infection, chickens were immunized with recombinant 3-1E protein in combination with AbISCO®-300 or recombinant 3-1E protein alone in this study. The protective immunity was assessed with body weight gain, fecal oocyst output, detection of intestinal IgA positive cells and percentages of CD3+, CD4+ or CD8+ intestinal intraepithelial lymphocytes (IELs). Chickens vaccinated with different doses of recombinant 3-1E protein plus AbISCO®-300 showed higher percentages of CD3+, CD4+, and CD8+ intestinal IELs, increased positive expression rate of intestinal IgA, increased body weight gains and decreased oocyst shedding compared with recombinant 3-1E protein-only vaccinated groups. The results showed that immunization with various doses of the recombinant 3-1E protein in AbISCO®-300 adjuvant enhanced immune protection against avian coccidiosis.

Molecular characterization of Cryptosporidium isolates from beef calves under one month of age over three successive years in one herd in western France

Cohorts of pre-weaned calves were studied for Cryptosporidium infection over three successive years (2010–2012) in one beef cattle herd in western France. Each year 25–34 calves were sampled weekly from 3 days to one month of age in order to characterize oocyst output, Cryptosporidium species and clinical features associated with infection. Faecal samples were screened for the presence of oocysts using immunofluorescence analysis. DNA was extracted from positive samples and a PCR SSU rRNA followed by RFLP or sequencing was performed. For the subtyping of C. parvum, a gp60 PCR was carried out. Regardless of the year, 92–100% of the animals excreted oocysts on at least one sampling date. Depending on the year of observation, the age of highest prevalence varied. In contrast, the peak of excretion was systematically observed almost at the same age (2nd–3rd week of life) with excretion levels ranging from between 100 and 1.7×107oocysts/g of faeces. Differences concerning clinical signs depending on the year of sampling were observed. Different species patterns were observed, with a predominance of C. bovis in the 1st year and a predominance of C. parvum in the last year. Moreover, two zoonotic subtypes of C. parvum, IIaA15G2R1 and IIaA18G2R1, were recorded in different years. This study shows that, in a given farm, the Cryptosporidium species and C. parvum subtypes identified as well as the prevalence of infection and level of excretion may vary greatly and show distinct patterns according to the year.

A low-virulence Eimeria intestinalis isolate from rabbit (Oryctolagus cuniculus) in China: molecular identification, pathogenicity, and immunogenicity

An Eimeria intestinalis isolated from a rabbit in China was first identified by amplifying the 18S small subunit (SSU) ribosomal RNA gene. The size of the amplified fragment was 1521 bp. The 18S SSU RNA gene of the E. intestinalis isolate shared 99% sequence identity with E. intestinalis isolates from France and the Czech Republic, with 100 and 96% coverage, respectively. Then, the pathogenicity and immunogenicity of the E. intestinalis isolate were evaluated in specific pathogen free (SPF) rabbits. In the pathogenicity assay, SPF rabbits in four groups were infected with 5 × 10(3), 5 × 10(4), 5 × 10(5), and 0 sporulated oocysts, respectively. Clinical signs including diarrhoea, constipation, loss of appetite, and reduction of body weight gain were observed in rabbits inoculated with 5 × 10(4) and 5 × 10(5) oocysts. And one rabbit (25 %) inoculated with 5 × 10(5) oocysts died 15 days after the inoculation. In the immunogenicity assay, SPF rabbits in five groups (named B1, B2, B3, B4, and B5) were immunised with 5 × 10(1), 5 × 10(2), 5 × 10(3), 0, and 0 sporulated oocysts, respectively. All rabbits but the B5 group were challenged with 1 × 10(6) oocysts. After the challenge, no or slight clinical signs were seen in rabbits of the B2 and B3 groups. Compared with the control, a 69.6 and 84.5% reduction of oocyst output was observed in the B2 and B3 groups, respectively. The body weight gain of the two groups was obviously higher than that of the challenge control group. All the results show that the E. intestinalis isolate has low virulence but immunogenicity in rabbit.

In vivo anticoccidial activity of berberine [18, 5,6-dihydro-9,10-dimethoxybenzo(g)-1,3-benzodioxolo(5,6-a) quinolizinium] – An isoquinoline alkaloid present in the root bark of Berberis lycium

Coccidiosis, caused by various Eimeria species, is a major parasitic disease in chicken. However the increasing resistance of these parasites to currently used anticoccidial drugs has stimulated the search for new methods of control. As part of this effort we investigated the root bark of Berberis lycium (barberry) as a potential source of compounds with anticoccidial activity. In the present study anticoccidial activity of different solvent extracts of the root bark of B. lycium and berberine was evaluated in vivo using broiler chicken. Results of the study demonstrated equipotent efficacy of pure berberine in comparison to that of standard drug amprolium on the basis of reduction in coccidian oocyst output, body weight gain of chicken and feed conversion ratio. Among the extracts crude methanolic extract showed highest anticoccidial activity tested at 300mg/kg body weight which could be due to the presence of alcohol-soluble active ingredients in root bark of B. lycium. Toxicological studies revealed that B. lycium extracts as well as berberine were not lethal up to dosage of 2000mg/kg body weight. LD50 was not determined as mortalities were not recorded in any of the five groups of chicken. From the present study it can be concluded that root bark of B. lycium has the immense potential to contribute to the control of coccidian parasites of chicken. Our results corroborate the use of berberine for treatment of severe diarrhoea, amoebiasis and intestinal infections and could justify its use in folk medicine for treatment of haemorrhagic dysentery.

Pharmacodynamic evaluation of a reference and a generic toltrazuril preparation in broilers experimentally infected with Eimeria tenella or E. acervulina

1. The aim of this study was to investigate the effects on pigmentation, faecal oocyst output, immune responsiveness and reactive oxygen species (ROS) generation following treatment with either the reference toltrazuril (Baycox) or a generic preparation (gen-TTZ), during an experimental Eimeria tenella (Et) or E. acervulina (Ea) infection of 210 Ross broiler chickens.2. Results showed a significant difference on the anticoccidial efficacy 6 d after treating infected animals with Baycox (Et: 99.69% and Ea: 99.52%) or gen-TTZ (Et:85.71% and Ea 81.81%).3. Gen-TTZ-treated animals were less strongly carotenoid-pigmented than Baycox-treated broilers. Mean plasma carotenoid concentrations were significantly higher in groups treated with Baycox than in broilers given gen-TTZ.4. Treatment of animals with Baycox led to a significant decrease in ability of the peripheral blood mononuclear cells to produce ROS in contrast to gen-TTZ-treated groups. Baycox, but not generic toltrazuril, increased IL-10 and decreased tumour necrosis factor alpha (TNF-α) concentrations in chickens infected with E. tenella and E. acervulina.5. It is suggested that differences in anticoccidial efficacy may be observed when using a generic toltrazuril product. Hence, in addition to plasma profiles of drugs, standardised clinical control tests may be necessary for generic formulations, particularly if other parameters are important to achieve a better control of coccidiosis.

Eimeria falciformis infection of the mouse caecum identifies opposing roles of IFNγ-regulated host pathways for the parasite development.

Intracellular parasites reprogram host functions for their survival and reproduction. The extent and relevance of parasite-mediated host responses in vivo remains poorly studied, however. We utilized Eimeria falciformis, a parasite infecting the mouse intestinal epithelium, to identify and validate host determinants of parasite infection. Most prominent mouse genes induced during the onset of asexual and sexual growth of parasite comprise interferon γ (IFNγ)-regulated factors, e.g., immunity-related GTPases (IRGA6/B6/D/M2/M3), guanylate-binding proteins (GBP2/3/5/6/8), chemokines (CxCL9-11), and several enzymes of the kynurenine pathway including indoleamine 2,3-dioxygenase 1 (IDO1). These results indicated a multifarious innate defense (tryptophan catabolism, IRG, GBP, and chemokine signaling), and a consequential adaptive immune response (chemokine-cytokine signaling and lymphocyte recruitment). The inflammation- and immunity-associated transcripts were increased during the course of infection, following influx of B cells, T cells, and macrophages to the parasitized caecum tissue. Consistently, parasite growth was enhanced in animals inhibited for CxCr3, a major receptor for CxCL9-11 present on immune cells. Interestingly, despite a prominent induction, mouse IRGB6 failed to bind and disrupt the parasitophorous vacuole, implying an immune evasion by E. falciformis. Furthermore, oocyst output was impaired in IFNγ-R(-/-) and IDO1(-/-) mice, both of which suggest a subversion of IFNγ signaling by the parasite to promote its growth.