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Scarcity of gamma delta T cells in intestinal epithelia containing coccidia despite general increase of epithelial lymphocytes.

Lymphocytes of intestinal epithelia were examined in lambs experimentally infected with coccidia. Fourteen conventional, coccidia-free 3-week-old lambs of the Dala breed were given either 250,000 (eight lambs in experiment 1) or 100,000 (six lambs in experiment 2) sporulated oocysts of Eimeria ovinoidalis (> 99.9% pure) via a stomach tube. Nine lambs (five in experiment 1 and four in experiment 2) of the same age served as uninoculated controls. The infected lambs developed diarrhea and dehydration between days 10 and 13 after infection. Intestinal specimens were collected 10-20 days after inoculation. A heavy multifocal infection of the epithelium comprising schizonts, gamonts, and oocysts resulted, with changes being most pronounced in the large intestine and the terminal part of ileum. Lesions included villous atrophy, villous fusions, and crypt hyperplasia. Computer-assisted morphometric analysis was applied to immunoperoxidase-stained sections for quantification of intraepithelial T cell subsets and included the distal jejunum of lambs of experiment 1. A significant increase in the epithelial area of the distal jejunum occupied by CD8+ lymphocytes was found in the infected lambs as compared with uninfected controls (18.3% versus 3.7%). The increased presence of CD8+ cells may be of significance in the intestinal immune response to ovine coccidiosis. A moderate, overall increase was also found for the gamma delta lymphocytes in the jejunal epithelium. Examination of the ileum of infected lambs of both experiments showed a scarcity of gamma delta cells (0.4% of epithelial area) in stretches of epithelium infected by coccida as compared with adjacent noninfected epithelium (4.0% of epithelial area).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Dung beetles, Onthophagus spp., as potential transport hosts of feline coccidia.

Cockroaches and filth-flies have been known to be transport hosts of Toxoplasma gondii but the role of dung beetles as the carrier of coccidian oocysts is not known. We attempted to clarify the role of dung beetles (Onthophagus spp.) as the transport host of feline coccidia including Toxoplasma. Toxoplasma oocysts were found in the feces of the beetles until day 3 after the insects were exposed to cat feces mixed with the oocysts. Furthermore, oocysts on the body surface of beetles were not easily detached but remained infective for a prolonged period of time. Infective dung beetles may contaminate the water with infective oocysts passed in their feces when they dropped into the water. In the field survey feline coccidia, Isospora felis and I. rivolta, were detected in dung beetles collected from dog feces; they play an important role in the transmission of feline coccidian oocysts in the field.

Animals↗

[Establishment of a colony of Japanese white rabbits free from coccidia and their breeding performance (author's transl)].

A colony of rabbits free from coccidia was established in 1974 by weaning young at 25 days of age from dams infected with coccidia. Until now Bordetella, Pasteurella and Psoroptes cuniculi have not been detected either, and neither diarrhea nor death has occurred in weanlings of the colony. However, the mortality of sucklings was significantly high owing to cannibalism and tread by their dams. The weaning rate was effectively improved by use of a large nursing cage (3,100 cm2) and sterilized hay on a stainless steel mesh floor of the nursing cage.

Animals↗

The relevance of laboratory diagnosis of human cryptosporidiosis and other coccidia.

Human infection by Cryptosporidium spp and other coccidia are due to opportunist non-host specific microorganisms. In HIV seropositive patients, the gastrointestinal symptoms accompanying such infections may be serious and prolonged and may include nausea, low-grade fever, abdominal cramps, anorexia and watery diarrhoea. We studied 188 stool samples from 111 patients (84 men and 27 women) with diarrhoea. A modified Ziehl-Nielsen technique for the detection of Cryptosporidium spp and Isospora belli was employed. The mean age of the patients was 31 years. Cryptosporidium spp was seen in 18% (n = 20) of the patients, 90% (n = 18) of whom were HIV seropositive. Isospora belli was recorded only from HIV seropositive patients (5.4% of all the patients studied and 6.5% of those who were HIV seropositive). These data confirm the good results obtained with this technique for the identification of Cryptosporidium spp and other coccidia and also reaffirm the clinical importance of correctly diagnosing the cause of diarrhoea, particularly in HIV seropositive patients.

Adolescent↗

Effects of low-level infections by coccidia and roundworms on the nutritional status of rats fed an adequate diet.

Experiments were conducted on male, Sprague-Dawley rats of the same age fed a standard laboratory diet to determine the comparative effects of single and concurrent subclinical infections by coccidia (Eimeria nieschulzi) and roundworms (Nippostrongylus brasiliensis) on nutritional status and metabolism. All infections produced anorexia, but it was more prolonged and intense with the concurrent ones. Feed:gain ratios were increased only by infections by nematodes alone, but average daily gains were reduced beyond the effect of anorexia (i.e., "specifically") only with the double infections. Infections by coccidia only, but not by nematodes only, specifically reduced the apparent digestibility of dry matter, organic matter and N; whereas only the apparent N digestibility was specifically reduced by the double infections. Balances of N were reduced in infected rats and pair-fed controls during anoretic periods, but significant differences between the daily means for infected and pair-fed rats occurred only erratically. Specific increases in urinary N loss did not occur with the single infections, but occurred on 2 d with the double ones. Increased losses of fecal N occurred with both coccidial and double infections, but they were much more pronounced in the latter. No effects of infection on the balances or carcass contents of Ca and P occurred. The only significant differences between mean empty carcass densities occurred with the double-infected and free-fed uninfected groups, with the mean for the uninfected group being the higher.

Animal Nutritional Physiological Phenomena↗

Establishment of a turkey cecal cell line and development of turkey coccidia within the cells.

Cells were dispersed from cecal tissues of 1- to 2-day-old turkeys using a mixture of collagenase and dispase to enrich for epithelial cells. The initial culture produced from these cells (TCC) appeared to be heterogeneous, but, as the cells were cultured through 25 passages, they assumed a more fibroblastic appearance. Cellular invasion of the TCC by two species of turkey coccidia, Eimeria adenoeides and Eimeria meleagrimitis, was not enhanced, as compared with invasion in turkey kidney cells (TKC), the cell culture system standardly used to study the avian coccidia in vitro. However, early development by one of the species, E. meleagrimitis, was markedly increased in the TCC (Passages 6 through 19) over that in TKC. Thirty to 42% of the parasites that invaded the TCC developed beyond the sporozoite stage, as compared with 5% development in TKC. Mature first-generation schizonts were observed within 24 hr postinoculation in the TCC, but not until 48 hr in the kidney cells. There was no evidence that development of the second generation was initiated in either the TCC or kidney cells.

Animals↗

Drug responsiveness of field isolates of chicken Coccidia.

Coccidia were isolated from litter samples collected in poultry houses in Georgia and other southeastern states and from intestinal scrapings from chickens submitted to diagnostic laboratories. The most common species of coccidia encountered were E. tenella, E. acervulina, and E. maxima. Each of the 41 isolates was tested for sensitivity to eight commercial anticoccidial drugs. Most of the isolates were resistant to some of the drugs judged by the parameters of percent weight gain, percent lesion score reduction, and a sensitivity index score. There was a high frequency of resistance to clopidol, amprolium/ethopabate, nequinate, zoalene, and sulfaquinoxaline. A very small percentage of the isolates tested were resistant to nicarbazin, robenidine, or halofuginone.

Amprolium↗

Coccidia of coyotes in eastern Colorado.

Eighty-two coyote fecal samples were collected from eastern Colorado and examined for coccidia. Sporocysts of Sarcocystis were observed in 17 of the samples and oocysts of Isospora ohioensis were observed in two samples. Ten fecal samples contained eimerian coccidia thought to be pseudoparasites of the coyote acquired while ingesting heavily infected rabbits.

Animals↗

An Eimeriid origin of isosporoid coccidia with Stieda bodies as shown by phylogenetic analysis of small subunit ribosomal RNA gene sequences.

Morphological and life cycle features of the tissue cyst-forming coccidia have been difficult to interpret in devising taxonomic classifications for the various genera. In this study, we amplified the full small subunit rRNA gene sequence of Isospora robini McQuistion and Holmes, 1988, and the partial sequence of Isospora gryphoni Olsen, Gissing, Barta, and Middleton, 1998 by PCR. Both of these species vary from Isospora species of mammals in having Stieda bodies on the sporocysts. The sequences were cloned and sequenced and were incorporated into an alignment with other Isospora species lacking Stieda bodies as well as with other coccidia. Maximum parsimony analysis of these sequences produced a single most parsimonious tree that placed I. robini and I. gryphoni in a clade containing various other eimeriid species. The Isospora species lacking Stieda bodies were in the sarcocystid clade. Similar results were found by maximum likelihood analysis. These findings indicate that the genus Isospora as defined by several authors is polyphyletic. Taxonomic changes to the genus Isospora would have to incorporate the 2 major clades found by molecular phylogenetic analysis. Isospora species with Stieda bodies should be classified in the family Eimeriidae, whereas those without Stieda bodies should remain in the family Sarcocystidae.

Animals↗

Application of biotechnological tools for coccidia vaccine development.

Coccidiosis is a ubiquitous intestinal protozoan infection of poultry seriously impairing the growth and feed utilization of infected animals. Conventional disease control strategies have relied on prophylactic medication. Due to the continual emergence of drug resistant parasites in the field and increasing incidence of broiler condemnations due to coccidia, novel approaches are urgently needed to reduce economic losses. Understanding the basic biology of host-parasite interactions and protective intestinal immune mechanisms, as well as characterization of host and parasite genes and proteins involved in eliciting protective host responses are crucial for the development of new control strategy. This review will highlight recent developments in coccidiosis research with special emphasis on the utilization of cutting edge techniques in molecular/cell biology, immunology, and functional genomics in coccidia vaccine development. The information will enhance our understanding of host-parasite biology, mucosal immunology, and host and parasite genomics in the development of a practical and effective control strategy against Eimeria and design of nutritional interventions to maximize growth under the stress caused by vaccination or infection. Furthermore, successful identification of quantitative economic traits associated with disease resistance to coccidiosis will provide poultry breeders with a novel selection strategy for development of genetically stable, coccidiosis-resistant chickens, thereby increasing the production efficiency.

Animals↗

Parasites of Chaffinch (Fringilla coelebs) population. Part I. Coccidia (Protozoa, Apicomplexa).

Coccidia infection in Chaffinch population in Mazurian Lakeland was studied. Birds were caught in mist nets from June to September and droppings were collected after defecation. Prevalence of infection was high -80% of Chaffinches excreted oocysts of Isospora sp. Intensity of oocysts' production varied depending on the time of the day and therefore coccidia prevalence in Chaffinch should be best detectable in birds caught after midday.

Animals↗

New species of Choleoeimeria (Apicomplexa: Eimeriidae) from the veiled chameleon, Chamaeleo calyptratus (Sauria: Chamaeleonidae), with taxonomic revision of eimerian coccidia from chameleons.

Coprological examination of 71 samples from a breeding colony of veiled chameleons, Chamaeleo calyptratus Duméril et Duméril, 1851, revealed a presence of two species of coccidia. In 100% of the samples examined, oocysts of Isospora jaracimrmani Modrý et Koudela, 1995 were detected. A new coccidian species, Choleoeimeria hirbayah sp. n., was discovered in 32.4% of samples from the colony. Its oocysts are tetrasporocystic, cylindrical, 28.3 (25-30) x 14.8 (13.5-17.5) microm, with smooth, bilayered, -1 microm thick wall. Sporocysts are dizoic, ovoidal to ellipsoidal, 10.1 (9-11) x 6.9 (6-7.5) microm, sporocyst wall is composed of two plates joined by a meridional suture. Endogenous development is confined to the epithelium of the gall bladder, with infected cells being typically displaced from the epithelium layer towards lumen. A taxonomic revision of tetrasporocystic coccidia in the Chamaeleonidae is provided.

Animals↗

[The observation of coccidia in swine].

The coccidia species of domestic pig and wild boar were compared and defined morphologically and the sporogony of both was examined. No difference could be detected between the coccidia species of domestic pig and wild boar. Six Eimeria and one Isospora species were found: Eimeria debliecki, E. polita, E. porci, E. scabra, E. spinosa, E. suis and Isospora suis. E porci could be found in Austria for the first time. E. cerdonis Vetterling, 1965 is a synonym of E. polita Pellérdy, 1949.

Animals↗

A survey of sensitivity to anticoccidial drugs in 60 isolates of coccidia from broiler chickens in Brazil and Argentina.

Coccidia were isolated from 90 broiler farms in 15 poultry-producing areas in Brazil and Argentina. Sixty isolates were tested for sensitivity to 7 anticoccidial drugs. The common species were: a) Eimeria tenella, 47 isolates; b) E. maxima, 49 isolates; c) E. acervulina, 44 isolates; d) E. mitis, 26 isolates; and e) E. brunetti, 12 isolates. Isolates were considered sensitive to drugs if intestinal lesion scores of medicated broilers were reduced by at least 50% compared with unmedicated infected broilers or if weight gain was at least 75% of that of uninfected birds in a 6-day laboratory test. According to lesion scores, there was evidence of resistance or seriously reduced sensitivity to monensin in 20 isolates, narasin in 29, salinomycin in 11, maduramicin in 1, clopidol in 36, amprolium in 40, and nicarbazin in 1. According to broiler weight gain, there was resistance to monensin in 36 isolates, narasin in 32, salinomycin in 28, maduramicin in 2, clopidol in 28, amprolium in 50, and nicarbazin in 4. These results suggested incomplete cross resistance of coccidia to polyether ionophorous drugs. The degree of resistance might be explained by previous patterns of use of these drugs.

Animals↗

Efficacy of ionophorous anticoccidial drugs against coccidia in farm-reared pheasants (Phasianus colchicus) from Illinois.

Litter samples obtained from a ring-necked pheasant propagation farm in Illinois contained coccidia: 57.5% of the oocysts were Eimeria duodenalis, 24.9% were E. tetartooimia, 8.8% were E. phasiani, and 8.8% were E. pacifica. Ionophorous anticoccidial drugs were tested for efficacy against the pheasant coccidia. All three drugs reduced oocyst production and prevented mortality in young pheasants; unmedicated infected controls had a 40% mortality rate. Monensin at 120 ppm in the feed was coccidiocidal against E. duodenalis and E. tetartooimia, partly coccidiocidal against E. pacifica, and only partly coccidiostatic against E. phasiani. Salinomycin at 60 ppm in the feed was highly efficacious and coccidiocidal against all four species, but the salinomycin-medicated pheasants gained the least of all medicated birds. Lasalocid at 120 ppm in the feed was the most effective, with nearly complete coccidiocidal activity against all four coccidial species.

Animals↗

Experimental infection of newborn calves with coccidia and reinfection after weaning.

Four newborn Hereford calves were orally inoculated five times with 100 sporulated oocysts of coccidia, predominantly Eimeria zurnii. Each calf was kept isolated with its dam until weaned at the age of 13 weeks. Three other newborn calves were similarly isolated but not experimentally infected. The calves were then challenged with 300,000 sporulated oocysts at the age of five, seven and nine months. The previously unexposed calves developed marked clinical coccidiosis after the first challenge, but resisted the second and third challenge. The neonatally exposed calves were susceptible to infection at the first challenge as well as to the next two challenges at seven and nine months of age, but the clinical signs following the last two challenges were milder than those of the first challenge. These findings suggest that under conditions where calves become infected with coccidia when very young, such calves may, by shedding oocysts in large numbers for long periods, be a continuing source of coccidial infections to other animals.

Age Factors↗

Attempeted transmission of feline coccidia from chronically infected queens to their kittens.

Eight female, 12- to 34-month-old, specific-pathogen free cats were inoculated orally with Toxoplasma gondii cysts on day 0, then with Isospora felis and Isospora rivolta oocysts on day 39, and cysts of Hammondia hammondi on day 86 after inoculation with Toxoplasma. All cats shed oocysts of all 4 of these coccidia within 11 postinoculation days. The female cats were caged with 4 male Toxoplasma-free cats, starting 66 days after inoculation with Toxoplasma, until they were 5 to 6 weeks pregnant. Kittens that were born were housed with their mothers until necropsied or weaned. One 42-day-old kitten shed T gondii oocysts in feces. It was necropsied 2 days later and asexual stages of Toxoplasma (types D and E), gametocytes, and oocysts were demonstrated in sections of superficial epithelial cells of its small intestine. Lesions or forms of Toxoplasma were not demonstrated histologically in tis extraintestinal organs. Toxoplasma was not isolated from feces or tissues of the remaining 47 kittens born to these 8 queens. Toxoplasma was not isolated from the 4 male cats that were caged with infected females for 53, 59, 217, and 217 days. The source of toxoplasma infection in the kitten remained unknown but was considered unlikely to be congenital or through fecal contamination. Oocysts of I felis, I rivolta, and H hammondi were not found in the feces of any kittens, indicating that these coccidia are unlikely to be transmitted congenitally.

Animals↗

Role of Coccidia in the occurrence of necrotic enteritis of chickens.

Clostridium perfringens type A, Eimeria acervulina, and Eimeria necatrix were used to produce necrotic enteritis in chickens. The disease was produced in all groups of birds that received feed contaminated with C. perfringens. Mortality due to necrotic enteritis was highest (53%) in birds infected with E. acervulina before infection with clostridia. There was a significant difference in mortality rates between birds infected with E. acervulina and birds infected with E. necatrix before infection with C. perfringens. Mortality rates also differed significantly between the group infected with E. necatrix and the group that received only feed contaminated with C. perfringens. It was concluded that under field conditions, coccidia can play a significant role in the occurrence of necrotic enteritis when a sufficient number of toxigenic strain of C. perfringens type A is present. The pathological changes induced by clostridia and coccidia are described.

Animals↗