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At least 19 recordsLinked to original sources
PubMed1976

Studies on site finding and site specificity of Eimeria praecox, Eimeria maxima and Eimeria acervulina in chickens.

Sporozoites of 3 species of Eimeria were introduced into the caecum of young chickens. E. praecox and E. maxima failed to develop in this site, but light infections of E. acervulina were detected. Infection of the small intestine with all 3 species occurred when sporozoites were introduced via the caecum. Infections were produced when mucosal scrapings of small intestine from birds, inoculated via the caecum 1-4 h previously, were inoculated orally to susceptible chickens. Experiments with 51Cr-labelled sporozoites of E. praecox introduced in the caecum, confirmed that small numbers of sporozoites are capable of migrating from the lower to the upper intestine. Sporozoites were not transferred with liver tissue from birds given sporozoites via the caecum but were transferred with the liver of chickens given sporozoites intraperitoneally.

Animals↗
PubMed1978

The appearance of bisporocytic oocysts of Eimeria maxima in drug-treated chicks.

A line of Eimeria maxima acquired resistance to Lerbek (a mixture of clopidol and methyl benzoquate) after serial passage against rising drug levels. Abnormal bisporocystic oocysts which appeared throughout this series were picked out individually and these produced infections in further groups of chicks. Serial passages of selected bisporocystic forms raised their proportion in oocyst yields to about 80% after 10-14 passages, but a few normal oocysts were still present.

Animals↗
PubMed1979

The fine structure of the developing macrogamete of Eimeria maxima.

The fine structure of the developing macrogamete of Eimeria maxima was studied from chicks killed at intervals from 138 to 147 h after inoculation. The macrogamete developed within a parasitophorous vacuole. Lying within the vacuole and extending for some distance around the periphery of the macrogamete were intravacuolar tubules, grouped in certain areas, and in some cases they were seen to make direct connexions with the cytoplasm of the parasite. During development, electron-pale vesicles were pinched off externally from the surface of the macrogamete. There appeared to be 2 forms of wall-forming bodies of the Type I during development, one form being less osmiophilic than the other. Other organelles present, such as wall-forming bodies of Type II, granular endoplasmic reticulum, mitochondria, canaliculi, lipid inclusions and intravacuolar folds, were similar in structure to those of other Eimeria species.

Animals↗
PubMed1975

The development of drug-resistant strains of Eimeria maxima in the laboratory.

The development of strains of Eimeria maxima resistant to buquinolate, methyl benzoquate, clopidol, sulphaquinoxaline and robenidine is described. It was not possible to standardize a schedule of inoculations and drug administration, which would enable the development of resistance to the different drugs to be compared directly. Resistance developed most readily to the quinolones. One robenidine-resistant strain proved to be drug-dependent. Dinitolmide showed unusual effects upon sporogony and three attempts to develop resistance against this activity failed. Chicks previously immunized with the parent strain were completely protected against infection with the drug-resistant strains.

Animals↗
PubMed1978

The activity of methyl benzoquate and clopidol against Eimeria maxima: synergy and drug resistance.

Synergy between clopidol and methyl benzoquate against Eimeria maxima was shown to be supra-additive. Collateral sensitivity to these drugs could not be demonstrated in resistant lines of this parasite. Resistance to methyl benzoquate and clopidol was not transferred when lines of E. maxima, resistant to the respective drugs, were propagated together. The failure to demonstrate this phenomenon was judged not to be due to synergy between the drugs. Attempts to induce simultaneous was readily acquired by a line of E. maxima resistant to clopidol. Induced resistance to clopidol in a methyl benzoquate-resistant line required numerous passages.

Animals↗
PubMed1978

Immunogenicity of a single sporocyst of Eimeria maxima.

Eight out of a total 40 chickens infected with single sporocysts of Eimeria maxima produced infective oocysts. These 8 chickens, when challenged with 4 X 10(5) oocysts per bird at 28 days postinfection, showed at least twice the percent average weight gain of the previously unexposed chickens, indicating that partial immunity was probably conferred by these infections. Also, these successful single sporocyst infections suggest that like E. tenella, sporozolles of E. maxima are probably sexually undifferentiated.

Animals↗
PubMed1975

Transferred drug-resistance in Eimeria maxima.

A series of experiments is described in which two drug-resistant strains of Eimeria maxima were passaged together in untreated chicks. The resultant oocysts were then inoculated into chicks treated with both drugs. When strains resistant to methyl benzoquate and sulphaquinoxaline or clopidol and sulphaquinoxaline were used the resultant infections were not controlled by the double treatment, indicating the acquisition of resistance factors by one strain from the other. When strains resistant to clopidol and methyl benzoquate were used the phenomenon was not observed.

Animals↗
PubMed1979

Immunological differences in Eimeria maxima: effect of a mixed immunizing inoculum on heterologous challenge.

The immunological differences known to exist between laboratory strains of Eimeria maxima was confirmed. Protection against challenge with different strains or field isolates of the species could be achieved by including small numbers (25 oocysts) of each in the immunizing inoculum. Similar protection was obtained when 4 distinct populations which were allowed to interbreed were used in the immunizing inoculum. This hybrid mixture of E. maxima was used to immunize chickens against challenge with 7 new isolates of E. maxima from poultry houses in different parts of England. The results show that although immunological differences exist within E. maxima good protection against many strains of this species may be achieved by initial infection with the hybrid mixture of E. maxima.

Animals↗
PubMed1977

The anticoccidial effects of amprolium, dinitolmide and monensin against Eimeria maxima, E, brunetti and E. acervulina with particular reference to oocyst sporulation.

Chicks infected with the Weybridge strains of Eimeria maxima and E. acervulina were not protected by the normal levels of amprolium, but the sporulation of the oocysts was inhibited. With higher drug concentrations, fewer oocysts were produced. E brunetti was not so markedly affected, although oocyst sporulation was reduced by the higher dosage levels. The effects were not enhanced by the inclusion of ethopabate. With dinitolmide the phenomenon was not so marked, although oocysts of E. maxima and E. acervulina were reduced in numbers by the normal drug concentration and sporulation was reduced when this level was increased. Much higher drug levels were required to obtain these effects with E. brunetti. Monensin at 120 ppm affected neither oocyst numbers nor their sporulation in any of the species tested. The significance of the effects of anticoccidial drugs on gametogony and sporogony is discussed.

Amprolium↗
PubMed1976

Eimeria maxima: a comparison of two laboratory strains with a fresh isolate.

Oocysts of the Weybridge and Houghton strains of Eimeria maxima and a fresh field isolate were similar and measured on average 30-9 X 22-4 mum. The Weybridge strain and the field isolate produced similar pathogenic effects in 6-week-old chickens, high doses causing 50-80% mortality and severe weight loss. The Houghton strain was slightly less pathogenic and few birds died but more oocysts were produced. With each strain, a single dose gave complete immunity to a light challenge with the homologous strain. Two or 3 immunizing doses gave complete immunity to a heavy homologous challenge but were not sufficient to protect against heterologous challenge.

Animals↗
PubMed1976

Immunity to coccidiosis: stages of the life-cycle of Eimeria maxima which induce, and are affected by, the response of the host.

An attempt was made to determine the relative importance of the different life-cycle stages of Eimeria maxima in the induction of immunity and also those stages most affected by the immune response of the host. In one experiment the life-cycle was controlled by chemotherapy but in all other experiments partial life-cycles were induced by transfers of infected mucosa between hosts. The results indicated that the second generation schizont stage is probably that most concerned in the induction of protective immunity and that sexual stages are most susceptible to immune inhibition. After initial inhibition in the immune host the earlier asexual stages were able to resume development when transferred to a susceptible host. The longer the period of exposure to the immune environment, the less able was the parasite to recover.

Animals↗
PubMed1979

Anticoccidial activity of narasin in battery raised broiler chickens.

The anticoccidial activity of the ionophorus antibiotic narasin was tested against six species of coccidia (Eimeria acervulina, Eimeria mivati, Eimeria maxima, Eimeria necatrix, Eimeria brunetti, and Eimeria tenella) in battery-raised broilers. Feeding ration medicated with 60, 80, or 100 ppm narasin significantly improved weight gains during the periods of D 0 to D7 and D 0 to D 14 (D 0 = day of inoculation with sporulated oocysts), compared with the weight gains in corresponding inoculated groups fed unmedicated feed. A similar protective effect of the medication was seen with feed conversion ratios (feed consumed/bird weight) and coccidiosis-induced mortality. With most species studied, 40 and 60 ppm narasin was not as efficacious as 80 or 100 ppm. The maximum numerial improvement in weight gain and feed conversion ratio was with 80 ppm narasin. Gross intestinal lesion scores were reduced by medication compared with the scores in birds fed unmedicated feed. The overall trend was for a larger reduction in lesion score with higher drug levels. Narasin at 80 or 100 ppm was generally more effective in controlling individual or mixed species infections of coccidia than 99 ppm monensin.

Animals↗
PubMed1978

Effect of coccidiosis on blood coagulation in broilers.

Severe infection with Eimeria acervulina, Eimeria maxima, Eimeria necatrix, and Eimeria tenella increased the prothrombin times in broilers compared with the times in uninfected birds. Recalcification time was not affected. The increase in prothrombin time was related to the severity of infection (as measured by lesion score), and was significant (P less than or equal to 0.05) only in the most severely infected birds. The increase was of short duration, lasting only 1 or 2 days, and first appeared on day 5 or 6 postinoculation. Restricting the feed intake of uninoculated birds to the amount of feed consumed by infected birds showed that the reduction in feed intake with coccidiosis was not responsible for the increase in prothrombin time.

Animals↗
PubMed1976

[Epizootiological and parasitological status of the flocks at a poultry combine].

A comprehensive epizootiologic study has been carried out at one of the large poultry dressing combines in this country. Results have shown that the part played by infections as against the remaining diseases established in the various technologic categories is as follows: 9 to 23.8 per cent in growing parents; 16.0 to 24.6 per cent in adult parents; and 4.8 to 13.4 per cent in broilers. So far as parasitic diseases are concerned the respective figures are 3.2 to 9.9 per cent, 3.0 to 3.3. per cent, and 2.9 to 3.0 to per cent. The import of birds from France and England intended for satisfying the needs of the poultry dressing combine in Roussé has contributed to the introduction of infections which have later on assumed an epizootic course, such as infections encephalomyelitis, infectious bronchitis, and Marek' disease. The epizootic status has been aggravated with the development of a number of diseases already existing in this country--fowl pox, lymphoid leukosis, chronic respiratory disease, salmonellosis, and above all infections caused by the so-called occasionally pathogenic agents--coli organisms, staphylococci, and Pseudomonas. Of the parasitic diseases only coccidiosis has developed, being caused by a variety of species: Eimeria acervulina, Eimeria necatrix, Eimeria maxima, Eimeria muvati and Eimeria tenella. The absence of helminth infections is due to the routinely adopted technological practice of raising birds in confinement and the strict veterinary control and guard. On the basis of the results obtained and the conclusions drawn some more effective prophylactic measures are suggested correcting and supplementing the existing prophylactic programme.

Animals↗
PubMed2026

Host immunological response of Ross 308 broilers fed an anti-IL-10 antibody to Eimeria and Clostridium perfringens challenge.

Understanding host response mechanisms may lead to improved management of poultry diseases such as necrotic enteritis. Ross 308 broilers (20 birds/cage, 32 cages) received diets &#xb1; anti-interleukin-10 (IL-10) antibody, an intervention to improve immune activation, in three experimental replicates (R1, R2, R3). R1 and R2 received 1 &#xd7; 108 colony forming units (CFU) Salmonella Typhimurium on day (d) 1. On d 14, birds were assigned to unchallenged control or 15,000 sporulated Eimeria maxima oocyst gavage challenge, with a subset receiving E. maxima + Clostridium perfringens (1 &#xd7; 10&#x2078; CFU d 18-19) to induce necrotic enteritis. Intestinal tissue and digesta samples were collected from 6 birds/treatment at baseline (d 14), peak infection (d 21), and post-peak infection (d 25) to measure luminal IL-10 (ELISA), interferon gamma (IFN&#x3b3;) via immunohistochemistry, and IL-10, CD4, CD8, CD25, and KUL01 via RNAscope. Data were analyzed via two-way ANOVA (P &#x2264; 0.05). In R3, baseline duodenal IL-10 was 458 ng/mg protein greater in birds fed the control diet, while E. maxima + C. perfringens inoculation increased jejunal and ileal IL-10 content by 528 and 649 ng/mg protein at peak infection (P < 0.05). In R2, peak jejunal tissue % IL-10 area increased during E. maxima + C. perfringens challenge (P < 0.05). Baseline and peak jejunal R3 RNA was sequenced on an Illumina NovaSeq 6000, mapped to the chicken genome, and differential expression identified with DESeq2 (|log&#x2082; fold change| > 1; FDR &#x2264; 0.05). At peak, E. maxima challenge overrepresented genes involved in cell cycle, lipid metabolism, and B cell proliferation (P < 0.002), while E. maxima + C. perfringens overrepresented defense response and catabolic process terms (P < 0.0001). Sex altered the host immune response to challenge (P < 0.05), while E. maxima &#xb1; C. perfringens induced a similar host immune response regardless of dietary anti-IL-10. Overall, pathogenic challenge status was the primary driver of host immune response with the effect of anti-IL-10 antibody influenced by S. Typhimurium.

Clostridium perfringens↗
PubMed1978

Effect of the anticoccidial arprinocid on production, sporulation, and infectivity of Eimeria oocysts.

Medication of broilers with arprinocid [MK-302, 9-(2-chloro-6-fluorbenzyl adenine)] had 3 distinct effects on oocysts; (1) the number of oocysts produced was decreased, (2) fewer of the oocysts sporulated, and (3) those oocysts which did sporulate were less infective than those from unmedicated birds. The drug level necessary to prevent passage of oocysts depended on the species and strain of coccidia. To essentially eliminate oocyst production (less than 5% of controls) required medication with the following levels of arprinocid: 70 ppm with Eimeria maxima; 60 ppm with E. mivati, E. E. necatrix, and E. brunetti; and 50 ppm with E. tenella. With E. acervulina, oocysts were completely eliminated by 60 ppm of arprinocid with one field strain but were still numerous at 70 ppm with a second field strain. Oocysts recovered from birds on medication often failed to sporulate. No sporulation was seen at drug levels of 30 ppm or above with E. maxima and E. mivati. The level of arpinocid required to prevent sporulation with other species depended on the strain being studied, but varied from 30 ppm to 70 ppm. The oocysts of E. acervulina, E. mivati, E. tenella, and E. brunetti recovered from medicated birds that subsequently sporulated, were less infective when inoculated into susceptible birds, than oocysts from unmedicated birds. Oocysts from low medication level with E. necatrix (30 ppm) and E. maxima (10 ppm), once sporulated, were as infective as oocysts from unmedicated control birds, even though the numbers produced were less. No differences were detected in the time oocysts were produced between medicated and unmedicated birds infected with E. acervulina, E. maxima, E. brunetti, and E. tenella.

Adenine↗