Eimeria spp. of domestic fowl: the migration of sporozoites intra- and extra-enterically

Chickens were dosed orally with sporulated oocysts of Eimeria acervulina, E. brunetti, E. maxima, or E. praecox and the subsequent presence, in various tissues, of parasites capable of inducing patent infections was detected by transferring the tissues to coccidia-free recipients. Similar results were obtained with each of the 4 species studied, irrespective of whether initial development occurs in the superficial (E. praecox, E. brunetti) or crypt (E. acervulina, E. maxima) epithelium. Infection was transferable by gut scrapings and liver homogenates at all time intervals (3, 6, 12, 18, 24, and 36 hr postinoculation) studied. Infection was also transferable with blood and with splenic homogenates but not consistently. Transfers made within a short time of the inoculation of donors were more successful in producing patent infections in the recipients. In all transfers the prepatent period was normal for the species. These findings suggest that sporozoites enter the mucosa very shortly after inoculation, and some of them pass to the liver and spleen and then leave these tissues at a somewhat slower rate, possibly to reenter the mucosa. Sporozoites in the lamina propria of the gut were found within host mononuclear cells in all 4 species studied. Most of the cells harbouring E. maxima and some of those with E. praecox were identified as intraepithelial lymphocytes while all others could only be identified as agranular mononuclear cells that were not characteristically macrophages.

Bile and serum immunoglobulin levels during primary and secondary infections with Eimeria tenella in chickens

Using a radial immunodiffusion assay, total bile and serum IgG, IgM and IgA were measured following primary and secondary exposures to Eimeria tenella. Neither IgG nor IgM could be detected consistently in bile. Biliary IgA peaked at Days 6 and 10 following a primary infection of either 5000 or 10,000 oocysts and remained elevated following a subsequent 10,000-oocyst challenge at Day 10. Serum IgG and IgM levels were not influenced by parasitism and measurable concentrations of serum IgA were not detected.

Development, growth, and migration of Philophthalmus gralli (Trematoda) from Jordan in the eyes of chicks

The growth of Philophthalmus gralli from Jordan was studied experimentally by inoculating 10 excysted metacercariae around the right eye of 47 day-old chicks. The growth rate was slow in the first three days during which flukes did not exceed 0.30 mm long. Then growth became rapid reaching 2.70 mm long on day 24. This was followed by a low growth rate during which the flukes grew from 2.70 mm to 2.90 mm on day 40. The flukes started to appear in the left eye on day 12 post-inoculation of metacercariae in the right eye. The recovery of flukes in the left eye increased from 5% on day 12 to 30% on day 32. The development of P. gralli from Jordan was the same as of other species of Philophthalmus. However, a sixth stage, post-maturation stage, is suggested in addition to the 5 developmental stages of Philophthalmus. The ratio of the transverse diameter of the ovary to that of testes in the post-maturation stage was 1:1.1-1:1.2.

Effect of infection with Eimeria tenella upon the cecal bacterial population in monoflora chickens

Monoflora chickens were established at 2 days of age by an oral inoculation with one of six species of bacteria (Lactobacillus acidophilus, Bifidobacterium thermophilum, Bacteroides vulgatus, Clostridium perfringens, Escherichia coli, or Streptococcus faecalis) and were infected with Eimeria tenella (5 X 10(4) oocysts per bird) 2 days later. There were two experimental groups for each bacterium: birds infected with bacteria alone and birds infected with a combination of bacteria and E. tenella. Seven days after E. tenella infection, counts of B. thermophilum in the cecal contents were significantly lower for E. tenella-infected birds than for those infected by B. thermophilum alone, whereas 10 days after E. tenella infection, counts were higher for E. tennella-infected birds. The population of L. acidophilus in the cecal contents of the E. tenella-infected chickens 10 days after inoculation was significantly greater than that in uninfected chickens. No significant differences were observed between the numbers of B. vulgatus, C. perfringens, and S. faecalis in cecal contents of groups with and without E. tenella infections.

In vitro hatching of the infective eggs of Ascaridia galli in tissue extracts

Extracts of proventriculus (PE) and small intestine (IE) of fowl were used, for the first time, as media for the in vitro hatching of infective eggs of Ascaridia galli. Hatching was successful in a mixture of equal parts of PE and IE (MIP) under normal air and under different concentrations of CO2, but not under 100% CO2. A very highly significant retardation (P less than 0.001) in the rate of hatching appeared as the concentration of CO2 was increased, indicating that high levels of CO2 inhibit the process of hatching. 100% of the eggs hatched in PE in 40.5 min whereas they did not hatch at all in IE, suggesting that IE alone has no influence on egg hatching. The shortest time taken for 100% of the eggs to hatch in this study suggests that the present method of hatching is faster than all previous methods used by different workers.

Cecal filling and defecation of chickens infected with Eimeria tenella

White Leghorn cockerels, 11 to 22 days old, were inoculated each with a single oral dose of 4-5 X 10(4) sporulated oocysts of Eimeria tenella. Radiographic study of urinary backflow in infected chickens injected with sodium iothalamate subcutaneously indicated that retrograde movement of ceca was impaired particularly 7, 10, and 14 days after infection. No inflow was noted 7 days after infection when barium sulfate was inoculated into cloaca. Weight of cecal contents examined 7 days after infection was significantly smaller than uninfected control. Number of cecal feces was counted every 24 h beginning 4 through 14 days after infection. The counts in infected birds were significantly fewer than uninfected control 8, 9, and 10 days after infection. Outflow of cecal contents was studied in chickens surgically injected with barium sulfate into cecum 7 days after infection. Radiographic study indicated that most of uninfected control ceca excreted or evacuated the medium between 10 and 24 h after injection, while a few infected birds cleared ceca during the same period.

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.

Experimental Cryptosporidium baileyi infections in chickens and turkeys produced by ocular inoculation of oocysts

Developmental stages of Cryptosporidium baileyi were observed on the conjunctival epithelium of 3 of 14 chicks and none of 7 turkeys following ocular inoculation of oocysts. No clinical signs of disease were observed in chicks or turkeys. All 14 chicks had developmental stages of C. baileyi in the cloaca, whereas 4 of the 7 turkeys were infected at this site.

Invasion of Salmonella typhimurium into the cecal wall of gnotobiotic chickens with Eimeria tenella

Salmonella typhimurium was recovered from cecal contents and the cecal wall of gnotobiotic chickens infected with S. typhimurium (10(4) cfu/bird) 2, 4, 6, or 8 days after Eimeria tenella infection (5 X 10(4) oocysts/bird) and killed 1 day after S. typhimurium infection. Bacterial counts in the cecal contents of chickens killed 5, 7, and 9 days after S. typhimurium and E. tenella infection were significantly greater than those in chickens infected with S. typhimurium alone. Number of S. typhimurium in the cecal wall of birds killed 5 or 7 days after coccidial infection were significantly greater than those of birds infected with S. typhimurium alone. It appears that S. typhimurium easily invaded the cecal wall, which had been damaged by coccidial infection.

Efficacy of maduramicin against ionophore-tolerant field isolates of coccidia in broilers

Maduramicin ammonium was given at 2.5-8 ppm in the feed to broilers experimentally infected with coccidia recently isolated from broiler farms where ionophores had been used for several years. Infection pressure varied from mild to severe in five trials: mortality in unmedicated controls ranged from 0 to 59%, intestinal lesion scores were high, and weight gain was depressed by the infections. The cultures of Eimeria were partly resistant to ionophores: birds medicated with monensin at 100-121 ppm had only modest reductions in lesion scores and incomplete protection against weight loss or mortality. Control of infections by maduramicin was significant at 4 ppm but best at 5-7 ppm. Maduramicin was more effective than monensin or narasin, but about the same as salinomycin, in reducing lesions and mortality and in protecting performance. Maduramicin was well tolerated within the dose range of 5-7 ppm.

Experimental cryptosporidiosis in broiler chickens

Seven-day-old conventional broilers were inoculated either orally or intratracheally (IT) with 2.5 X 10(5), 5.0 X 10(5), or 2.0 X 10(6) oocysts of Cryptosporidium baileyi (32 birds for each dosage level per group; 192 birds total). Thirty-two birds served as unninoculated controls. Mean weekly weight gain and feed conversion were determined during a 5-week period. Carcass pigment was graded using a Roche Color Fan. Fecal oocysts were calculated from random cage samples 6, 8, 11, 13, 15, 18, 20, 22, and 25 days after inoculation (DAI). Effects of C. baileyi on immune responses were examined for Newcastle disease virus-hemagglutination inhibition (NDV-HI) antibody, infectious bursal disease virus-enzyme-linked immunosorbent assay (IBDV-ELISA) antibody titers and delayed hypersensitivity (DH) in half of the birds in each group. Disease or death from cryptosporidiosis did not result from oral inoculation of C. baileyi. Signs of respiratory disease, consisting of rales, sneezing, and dyspnea were observed in all IT-inoculated birds 7 to 21 DAI. Seven deaths occurred in the IT-inoculated groups 14 to 21 DAI. At necropsy, lung parenchyma was gray, firm, and wet in the ventral region. Air sacs contained a foamy, white to gray, mucoid fluid. Histologic lesions in the air sacs and bronchi were epithelial hyperplasia, discharge of mucocellular exudate to the mucosal surface, thickening of the mucosa by cellular infiltrates, loss of cilia, and dilation of mucous glands. Weight gains for IT-inoculated birds were lower (P less than .05) than controls from 14 to 21 DAI, although weight gains for the 5-week period were not significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of dietary buffer additions on gain, efficiency, duodenal pH, and copper concentration in liver of Eimeria acervulina-infected chicks

Three experiments were conducted with broiler chicks to investigate the effect of dietary additions of NaHCO3(1%), A1(OH)3(.5%), kaolin(1%), A1(OH)2NaCO3(.23%), CaCO3(.37%), and MgO(1%) on gain, efficiency, duodenal pH, and liver Cu concentration of Eimeria acervulina-infected chicks. Experimental coccidial infection consistently reduced chick gain, efficiency, and duodenal pH, but it increased liver Cu concentration of chicks fed excess Cu. Sodium bicarbonate addition improved chick gain and efficiency slightly, whereas the MgO addition reduced these performance criteria. Sodium bicarbonate improved gain more in coccidiosis-infected chicks than in uninfected chicks, but it failed to alleviate, to any extent, the coccidiosis-induced liver Cu increase of the duodenal pH decrease.

A redescription of the life cycle of Eimeria mitis Tyzzer, 1929

Ten-day-old broiler chickens were inoculated with oocysts of a characterized strain of Eimeria mitis, and tissues were fixed at 4, 8, or 24-h intervals after inoculation for histopathological examination. Tissue collections were initiated at the time of inoculation and extended up to 168 h postinoculation. The preferred site of development of E. mitis was found to be the ileum although more limited development of the parasite also took in the jejunum, cecal pouches, cloaca, and bursa of Fabricius. No distinctive and consistent intestinal lesions were macroscopically evident even in heavily parasitized chickens. The prepatent period was approximately 92 h postinoculation. The histopathological features of the E. mitis infections were characterized using conventional bright-field microscopy as well as both scanning and transmission electron microscopy. No extra-intestinal development of the parasite was observed.

In vitro excystation of Cryptosporidium baileyi from chickens

Release of sporozoites from the oocysts of Cryptosporidium baileyi is described from Nomarski interference-contrast microscopy. Just prior to excystation, the four sporozoites became motile and rearranged themselves within the oocyst. The sporozoites were then rapidly expelled through an opening that formed in the oocyst wall, and the residuum was either released or retained within the oocyst. Excysted sporozoites were crescent shaped and measured 5.0-9.0 microns X 1.0-1.6 micron (mean = 6.8 X 1.1 microns). Excystation occurred when sodium taurocholate or a mixture of trypsin and sodium taurocholate was present in the incubation medium. High levels of excystation occurred at 37 degrees or 40 degrees C, but excystation did not occur at 4 degrees C. The ability of biles from two avian and two mammalian hosts to produce excystation of C. baileyi was also studied. After a 2-h incubation at 40 degrees C, the percentages of excystation were 69.5% in goat bile, 45.0% in pig bile, 33.0% in chicken bile, and 34.5% in turkey bile.

Gut stasis in chickens infected with Eimeria

The duration and locations of gut stasis were examined in chickens infected with either Eimeria acervulina or E. maxima. Gut passage time (GPT) was used to determine gut stasis. The location of feed retention was determined qualitatively and quantitatively. Infections with both species were associated with increased GPT from Days 5 to 13 postinoculation. Feed appeared to be retained in the crop and gizzard of infected birds when judged visually. However, measurements of total dry matter retained in various regions of the gastrointestinal tract did not differ significantly from each other.

Ultrastructural studies of the effects of amprolium and dinitolmide on Eimeria acervulina macrogametes

Medication of chicks with 125 ppm amprolium or dinitolmide adversely affected oocyst sporulation of Eimeria acervulina (Weybridge strain). Dinitolmide delayed oocyst production and no oocyst wall formation was seen up to 168 h post infection. Both drugs caused large numbers of abnormally small wall-forming bodies to be produced in the macrogametes. In amprolium-fed chicks, abnormal oocyst wall formation was seen. It was concluded that the main drug action was against wall forming bodies of type 2.

Effect of Eimeria acervulina infection on chick (Gallus domesticus) high density lipoprotein composition

1. Plasma high density lipoprotein (HDL), the principal carotenoid carrier in broiler chicks, was analyzed at zero time and 3, 5 and 7 days after inoculation of chicks with the intestinal coccidial parasite, Eimeria acervulina. 2. Infection caused significant decreases in total HDL mass from 3 through 7 post-inoculation (PI), and decreases in relative percents of protein and carotenoids, and relative increases in phospholipid and cholesterol esters by 7 days PI. 3. Carotenoid content correlated best with protein content (principally apolipoprotein A-I) throughout the experiment. 4. Findings emphasize the importance of the small intestinal mucosa as a source of plasma HDL in the broiler chick, and suggest that apolipoprotein A-I is the binding site for HDL carotenoids.

Experimentally induced infections in turkeys with Cryptosporidium baileyi isolated from chickens

Oocysts of Cryptosporidium baileyi isolated from chickens were inoculated by different routes into 3 groups of turkey poults. Intratracheal inoculation of oocysts produced clinical signs of respiratory tract disease, deaths, and gross lesions of airsacculitis. Parasites developed in the microvillous border of the nasopharynx, larynx, trachea, bronchi, and air sacs. Oral and intracloacal inoculations of oocysts caused no deaths or clinical signs of disease, but did produce patent infections. Respiratory tract infections limited to the nasopharynx, larynx, and trachea occurred in 3 orally inoculated poults. Respiratory tract infections were not observed in intracloacally inoculated poults. The mode of inoculation did not influence the distribution of C baileyi in the digestive tract. The cloaca was parasitized in 100% of the birds with intestinal infections, and the bursa of Fabricius was parasitized in 72.7%.

Comparison of disease susceptibility and subclass-specific antibody response in SC and FP chickens experimentally inoculated with Eimeria tenella, E. acervulina, or E. maxima

Susceptibility to disease and the subclass-specific antibody response to Eimeria tenella, E. acervulina, and E. maxima were compared in two inbred strains of chickens, FP (B15B21) and SC (B2B2). FP strain was more susceptible to coccidiosis than SC chickens based on oocyst production, lesion score, and clinical signs. FP chickens infected with E. tenella had more severe cecal lesions and a significantly lower hematocrit level than SC chickens. FP chickens infected with E. acervulina excreted five times as many oocysts at 6 days postinfection as SC and showed a 71% reduction in plasma carotenoid level compared with controls (56% reduction in SC chickens). Body-weight change did not correlate with other signs of disease. Both SC and FP chickens produced high levels of serum IgM and IgG and biliary IgA. Although SC chickens had a slightly higher antibody response than FP chickens at 7 days postinoculation, both strains maintained high levels of IgM, IgG, and IgA for a prolonged period post primary inoculation. Although SC and FP chickens show different disease susceptibility to coccidiosis, they demonstrate similar antibody response.

Light microscopical study of Blastocystis spp. in monkeys and fowls

An investigation of a Blastocystis species obtained from several species of monkeys and fowls was conducted to clarify the morphology of the organism, using light microscopical techniques including Giemsa, Heidenhain iron hematoxylin, Trichrome stains, iodine mount and phase-contrast microscopy. A comparison was made with Blastocystis hominis from humans. Blastocystis spp. were found in 15 out of 26 monkeys and in all of 12 fowls (10 chickens and 2 ostriches) examined. The behaviour of the parasites in the bowels was also examined, using paraffin-embedded sections. Microscope examination of the lumen contents at death revealed the organism in the caecum of monkeys and fowls. The organisms from faeces, cultures and the lumen contents of the caecum of humans, monkeys and fowls were similar, except for variations in the size and contents of the central vacuoles, which occupied the centre of the organisms.

[Epidemiological importance of the animal reservoir of Trypanosoma brucei gambiense in the Congo. 1. Prevalence of animal trypanosomiasis in the foci of sleeping sickness]

Parasitological and serological tests were performed in 1287 domestic animals originating from the Brazzaville area and three sleeping sickness foci in Congo. Nannomonas and Trypanozoon were the only sub-genera present in the blood of animals, with prevalences of 16.9% and 0.5%, respectively. The use of Testryp CATT allowed a better estimation of the real frequency of animal trypanosomiasis which in some foci, was found to be three times higher than the parasitological prevalence. Seven stocks of Trypanozoon were isolated from pigs and sheep. A biochemical analysis indicated that they belonged to the T.b. gambiense sub-species. However, considering the low prevalence of T.b. gambiense infections in animals, it is doubtful that this reservoir plays an important epidemiological role.

Precluding coccidiosis with an anti-coprophagia drug

Floor-pen studies were conducted to ascertain whether coccidiosis could be prevented by using a drug added to the litter to preclude coprophagia and ingestion of infective oocysts. An experimental drug (1-pyrrolidinebutyramide, 2-methyl-alpha,alpha-diphenyl) was added to litter contaminated with sporulated Eimeria tenella oocysts. Thereafter 7-day-old broiler chicks were reared on the litter for a nine-day period. Mortality, lesion scores and dropping scores were the criteria selected to determine efficacy. Treatment of the litter at the lowest level (2.3 g kg-1) did not reduce the incidence or severity of the disease, whereas treatment at two higher levels (11.5 and 23.0 g kg-1) significantly reduced both (incidence and severity). The highest level was the most efficacious; however, drug toxicity was also encountered at this level.

Anticoccidial activity of 9-(2-chloro-6-fluorobenzyl)-6-methylaminopurine and 9-(2-chloro-6-fluorobenzyl)-6-dimethylaminopurine against Eimeria tenella, E. acervulina, and E. maxima in battery trials

In a series of battery experiments utilizing 9-day-old White Leghorn male chicks, 9-(2-chloro-6-fluorobenzyl)-6-methylaminopurine (VM 6387) and 9-(2-chloro-6-fluorobenzyl)-6-dimethylaminopurine (VM 6736) showed remarkable anticoccidial activity against Eimeria tenella, E. acervulina, and E. maxima. The effective dose range was estimated from the results of the efficacy test against E. tenella on the basis of improvement of body weight gain and clinical signs of infection. The tests included dietary levels of 60-100 ppm of VM 6387 and 70-110 ppm of VM 6736. Both compounds gave good protection against E. acervulina and E. maxima at the same dose range. The sporulation of oocysts obtained from cecal contents of birds fed lower levels of VM 6387 was inhibited. Studies of the effects of VM 6387 on stages of the E. tenella life cycle demonstrated that the compound possesses remarkable activity at 1-5 days post-infection corresponding to the period of schizogony, as well as prolonged activity thereafter, when the parasite was undergoing gametogenesis.

Microelements in the circulation of coccidiosis-infected chicks

Four-week-old Single Comb White Leghorn male chicks were inoculated with either Eimeria acervulina, E. necatrix, E. brunetti, E. tenella, or left uninfected. On Days 1, 3, 5, 6, 7, 8, 9, 10, 14, 21, 28, and 35 after inoculation, blood was removed from five birds in each group; content of copper, zinc, and iron in plasma and total iron-binding capacity were determined. Copper content in plasma was increased during the acute phase of the infections by lower intestinal tract (E. brunetti, E. tenella) infections but not by upper tract (E. acervulina, E. necatrix) infections. Zinc content in plasma was decreased by E. acervulina and E. necatrix infections on the 7th day and was increased by E. acervulina, E. brunetti, and E. tenella infections on the 9th or 10th days. Iron content in plasma was decreased during the acute phase (Days 5 to 7) of E. acervulina, E. brunetti, and E. tenella infections. Total iron-binding capacity was decreased by acute phase E. acervulina and E. brunetti infections. Eimeria tenella infections increased total iron-binding capacity during both the acute and early recovery phases. Plasma content of all components returned to normal by the latter part of the recovery phase of the infections and remained so thereafter. Plasma trace mineral content appeared to be influenced by mineral absorption effects, by hemorrhaging, and perhaps by invasion of the bloodstream by gut bacteria as a result of mucosal damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Drug-sensitivity of 99 isolates of coccidia from broiler farms

Coccidia were isolated from 99 broiler farms in 12 broiler-producing states and tested for sensitivity to contemporary anticoccidial drugs. The isolates usually comprised two or more species, including 92 Eimeria acervulina, 47 E. maxima, 28 E. tenella, and 10 E. brunetti. Based on intestinal-lesion-score reduction of 30% or more, 38% of isolates were resistant to monensin (110 ppm), 29% to salinomycin (60 ppm), 20% to nicarbazin (125 ppm), and 46% to amprolium + ethopabate (125 + 4 ppm). Isolates with 50% or greater reduction of lesion scores were considered sensitive. Thirty-three percent were sensitive to monensin, 53% to salinomycin, 67% to nicarbazin, and 39% to amprolium + ethopabate. Other isolates had intermediate response to drugs and were considered to have "reduced sensitivity." There was some evidence for incomplete cross resistance to the polyether, ionophorous products.

Further investigation of the dietary protein and monensin level interrelationship in broiler chicks: influence of Eimeria acervulina infection, increased dietary protein, and level of feed intake

Three experiments were conducted to evaluate the influence of several dietary factors on the monensin response in commercial broiler chicks fed corn-soybean meal diets varying in crude protein (CP). All experiments were conducted between 8 and 22 days posthatching. Trial 1 had a 2 X 2 X 2 factorial design wherein diets containing 16 or 24% CP and 0 or 121 mg/kg monensin were fed in the presence and absence of Eimeria acervulina infection. The monensin-induced growth depression was greater at 16% CP than at 24% CP. Coccidial infection had no effect on the monensin X protein level interaction. Monensin supplementation markedly improved performance of chicks infected with E. acervulina. Trial 2 was conducted to determine if the monensin-induced depression in performance caused by feeding a high level of monensin (140 mg/kg) could be moderated by feeding a high protein diet. Monensin supplementation reduced growth rate 18 and 10% in chicks fed 20 and 24% CP, respectively. Increasing CP to 28% alleviated the adverse effects of monensin on weight gain. Pair-feeding was used in Trial 3 to determine the extent to which the monensin-induced growth depression observed in chicks fed low protein diets was due to reduced feed intake. As expected, reducing the dietary CP from 24 to 16% resulted in a marked increase in the growth depression caused by 121 mg/kg monensin. Pair-feeding indicated that most of monensin's adverse effects in low protein diets could be attributed to its anorexic properties.

Resistance to natural and controlled exposures to Eimeria tenella: genetic variation and alloantigen systems

Chickens from lines selected for high (HA) and low (LA) antibody response to sheep erythrocyte antigens were used to study relationships between blood group systems and resistance to Eimeria tenella. Results of natural and controlled exposures to E. tenella showed Line HA chickens to be more resistant than those from Line LA. Differences in resistance to E. tenella were found among alleles for the I blood group system with degree of resistance depending on the background genome.

Dose-titration of fenbendazole in the treatment of poultry nematodiasis

Broiler chickens were fed ad libitum diets containing fenbendazole at various concentrations and durations for the removal of adult Ascaridia galli, Heterakis gallinarum, and Capillaria obsignata. All regimens were 100% effective against A. galli. Fenbendazole at doses of 80 ppm for 3 days and 48 or 30 ppm for 5 days was 100% effective against H. gallinarum. C. obsignata was not removed completely by any regimen, but greater than or equal to 95% effectiveness was seen in birds given fenbendazole at doses of 80 ppm for 3 days and 48 ppm for 5 days. All medicated rations were readily consumed, and the treated birds exhibited no adverse reactions.

Growth and feeding of Echinostoma revolutum on the chick chorioallantois and in the domestic chick

Chemically excysted metacercariae of Echinostoma revolutum cultivated on the chick chorioallantois grew slowly until day 5, more rapidly between 5 and 7 days, and slowly between 7 and 10 days. Worms did not become ovigerous in this site by 12 days, at which time studies were terminated. In contrast, chemically excysted metacercariae reared in the domestic chick were ovigerous by day 9, at which time their mean body area was about 4 times greater than the largest chorioallantoic worms. Histochemical studies, solubility tests for hematin, and X-ray microanalysis of cecal contents showed that chorioallantoic-worms fed on blood from the vascular membrane, whereas chick-worms fed on host intestinal mucosa.

Effect of mild infections with six species of Eimeria on skin pigmentation of broiler chickens

Mild infections of Eimeria maxima, E. acervulina, E. mivati, E. brunetti, E. necatrix, or E. tenella that did not affect weight gain significantly (P greater than .05) caused significant (P less than .05) shank depigmentation in 6-week-old broilers fed a broiler diet. Infections of E. maxima, E. mivati, or E. acervulina caused numerically more depigmentation than did infections by E. tenella, E. brunetti, or E. necatrix. Significant depigmentation was first detected at 4 days postinoculation (pi) with some species, prior to other gross evidence of infection, and infected birds regained little lost pigment by 14 days pi. Pigmentation among the infections by different species from the time of innoculation to 14 days pi was not significantly different (P greater than .05) amongst the treatments.

Detection of chicken antibody to the protozoan parasite Eimeria tenella by antigen-coated microspheres

A sensitive immunoassay for detecting antibodies to the protozoan parasite of poultry Eimeria tenella, has been developed. Microspheres coated with parasite antigen are reacted with antibody-containing chicken serum followed by a fluorescent labeled second antibody and analyzed by flow cytometry. The assay was used to demonstrate that chickens, vaccinated with E. tenella sporozoite antigen, showed significant elevations in serum antibody levels after exposure to infection compared to non-vaccinates. The assay is reproducible and because antigen-coated microspheres are stable for up to 4 weeks at 4 degrees C, a single batch can be used to analyze multiple serum samples.

Avian coccidiosis: the administration of encapsulated oocysts

Oocysts of fowl coccidia, suspended in a 12% aqueous solution of alginic acid, were dropped into 5% calcium chloride solution to form beads. Following ingestion by chicks, excystation of sporozoites was not affected. Oocyst viability was best when beads were air-dried to 33% of their original weight and stored in airtight containers at 4 degrees C. Infectivity was fully maintained for 8 weeks. Trickle infection, using beads administered orally to 2- or 3-week-old chickens, or mixed daily in food of chicks from 1-day-old, established a high level of immunity. This method of oocyst administration offers some practical advantages for the conduct of immunity and chemotherapy experiments.

Eimeria tenella: experimental studies on the development of resistance to halofuginone

Resistance to halofuginone has been developed by serially passaging the Houghton strain of Eimeria tenella in chickens medicated with progressively greater concentrations of drug. Attempts to develop resistance to 3 ppm (as recommended for use by the manufacturer) or higher concentrations, by the method of Weppelman et al., were unsuccessful.

The life cycle of Cryptosporidium baileyi n. sp. (Apicomplexa, Cryptosporidiidae) infecting chickens

The life cycle and morphology of a previously undescribed species of Cryptosporidium isolated from commercial broiler chickens is described. The prepatent period for Cryptosporidium baileyi n. sp. was three days post oral inoculation (PI) of oocysts, and the patent period was days 4-24 PI for chickens inoculated at two days of age and days 4-14 for chickens inoculated at one and six months of age. During the first three days PI, most developmental stages of C. baileyi were found in the microvillous region of enterocytes of the ileum and large intestine. By day 4 PI, most parasites occurred in enterocytes of the cloaca and bursa of Fabricius (BF). Mature Type I meronts with eight merozoites first appeared 12 h PI and measured 5.0 x 4.9 micrometers. Mature Type II meronts with four merozoites and a large granular residuum first appeared 48 h PI and measured 5.1 x 5.1 micrometers. Type III meronts with eight short merozoites and a large homogeneous residuum first appeared 72 h PI and measured 5.2 x 5.1 micrometers. Microgamonts (4.0 x 4.0 micrometers) produced approximately 16 microgametes that penetrated into macrogametes (4.7 x 4.7 micrometers). Macrogametes gave rise to two types of oocysts that sporulated within the host cells. Most were thick-walled oocysts (6.3 x 5.2 micrometers), the resistant forms that passed unaltered in the feces. Some were thin-walled oocysts whose wall (membrane) readily ruptured upon release from the host cell. Sporozoites from thin-walled oocysts were observed penetrating enterocytes in mucosal smears. The presence of thin-walled, autoinfective oocysts and the recycling of Type I meronts may explain why chickens develop heavy intestinal infections lasting up to 21 days. Oocysts of C. baileyi were inoculated orally into several animals to determine its host specificity. Cryptosporidium baileyi did not produce infections in suckling mice and goats or in two-day-old or two-week-old quail. One of six 10-day-old turkeys had small numbers of asexual stages only in the BF. Four of six one-day-old turkeys developed mild infections only in the BF, and sexual stages of the parasite were observed in only one of the four. All seven one-day-old ducks and seven two-day-old geese developed heavy infections only in the BF with all known developmental stages present.

Observations on the Taiwanese strain of Leucocytozoon caulleryi (Haemosporina) in chickens

The Taiwanese strain of Leucocytozoon caulleryi was isolated from an infected chicken in Taipei, Taiwan, and established in chickens and biting midges Culicoides arakawae from Japan. Sporogony of the strain in C. arakawae was completed on day 3 after the infective blood meals at 25 degrees C. Sporozoites isolated from the salivary glands of C. arakawae on days 3 or 4 after feeding caused infection in all the chickens inoculated. The strain showed high pathogenicity for chickens. Mortality of chickens rose with an increase in the number of sporozoites inoculated. The prepatent period for chickens inoculated with sporozoites was 14 days. Parasites appeared in the peripheral blood of chickens on day 15 and disappeared on day 26 after sporozoite inoculation. Soluble antigens were found in the sera of chickens infected with the strain between 10 and 17 days after inoculation, and homologous antibodies appeared after 17 days. Antigens prepared from sera, schizonts, merozoites, and gametocytes of the Taiwanese strain reacted with the sera of chickens infected with the same strain or the strain isolated in Japan. The chickens that recovered from a primary infection with the Taiwanese strain demonstrated complete resistance to reinfection with the same strain or the the strain isolated in Japan.

Effects of cage contamination with coccidia and salmonella on acute salmonellosis in young chickens

The effects of concurrent cage contamination with Salmonella typhimurium and Eimeria tenella on the establishment of salmonella infection in day-old chickens were investigated. Chickens were divided into five groups: uninfected recipient birds placed in a cage contaminated by donor birds infected with E. tenella and S. typhimurium; E. tenella-infected recipients placed in a cage contaminated by S. typhimurium-infected donors; uninfected recipients placed in a cage contaminated by S. typhimurium-infected donors; E. tenella-infected recipients placed in a cage contaminated by uninfected donors; and uninfected recipients placed in a cage contaminated by uninfected donors. Three identical trials were conducted. Recipient birds were necropsied 4, 7, and 11 days after caging. In the cage where donor birds infected with both organisms had been reared, S. typhimurium counts in feces and number of feces positive for S. typhimurium were significantly (P less than 0.05) greater than those in the other cages on days 0, 4, and 7 after caging. Moreover, in this cage, more chicks died, counts of S. typhimurium in cecal contents were greater, and more birds were positive for S. typhimurium than in the other groups. This suggests that S. typhimurium infection in day-old chickens is enhanced in cages contaminated with E. tenella and S. typhimurium compared with infection in cages contaminated with S. typhimurium alone.

A study of the dynamics of the invasion of immunized birds by Eimeria sporozoites

The invasion of the intestinal epithelium of immunized and unimmunized turkeys and chickens by four species of Eimeria was quantitated. In unimmunized birds, E. adenoeides, E. acervulina, and E. tenella invaded primarily the areas in which first-generation schizonts subsequently developed. Eimeria meleagrimitis invaded a larger area of the intestine. Between 1 and 4 hr postinoculation, the numbers of intracellular sporozoites increased, but their location within the intestine was little changed. When birds were immunized with either of two lower intestinal species, E. adenoeides or E. tenella, and then challenged with the immunizing species, invasion was reduced by 36% to 55%. In contrast, immunizing and then challenging birds with either of two upper intestinal species, E. meleagrimitis or E. acervulina, did not reduce invasion: there were 44% more intracellular sporozoites in E. meleagrimitis-immunized turkeys and 11% more in E. acervulina-immunized chickens than in their unimmunized counterparts.

Increased biting rate and reduced fertility in sporozoite-infected mosquitoes

Because salivary function and blood location are impaired in sporozoite-infected mosquitoes, we determined whether such pathology also could lead to an increased biting rate. For 5 days, we compared relative daily biting rates of Plasmodium gallinaceum sporozoite-infected mosquitoes (Aedes aegypti) and noninfected mosquitoes with an olfactometer. Mosquitoes then were exposed for 5 min to an anesthetized guinea pig. Infected mosquitoes exhibited a significant increase in olfactometer response which was also reflected in a decreased egg output. We conclude that if duration of contact with a host is limited, then infected mosquitoes may make more attempts at probing before being successful, and thus enhance transmission.

Effects of different feather lengths in the vent area of White Leghorn hens on northern fowl mite populations

Two tests of mature White Leghorn laying hens with feathers in the "vent area" clipped to less than .5, 1.5, or 2.5 cm in length were compared with unclipped hens to determine the differences in northern fowl mite (NFM) populations following artificial infestation. Weekly mite ratings were recorded for: 1) the total hen's body, 2) only the vent area, and 3) the remainder of the hen's body. In both tests, the mean total NFM populations were progressively greater as the clipped length of the feathers increased for 16 weeks postinfestation. Mean NFM populations in only the vent area were significantly less for hens with feathers clipped to less than .5 cm in both tests. There was no significant increase in NFM populations over the rest of the hen's body as a result of feathers clipped in the vent area. Therefore, it would be possible to control NFM at relatively low levels without the use of pesticides if a method for reducing the length of feathers in the vent area of laying hens could be developed.

Macroelements in the circulation of coccidiosis-infected chicks

Four-week-old Single Comb White Leghorn (SCWL) chicks were inoculated with either Eimeria acervulina, E. necatrix, E. brunetti, E. tenella, or left uninfected. On the 1st, 3rd, 5th, 6th, 7th, 8th, 9th, 10th, 14th, 21st, 28th, and 35th days after inoculation, blood was removed from five birds in each group, and the content of calcium, magnesium, sodium, potassium, hemoglobin, erythrocytes, and packed cell volumes were determined. Hemoglobin, erythrocyte concentrations, and hematocrits all decreased during the acute phase of the infections and returned to normal during recovery. Plasma calcium concentrations were significantly decreased by the upper intestinal tract infections, but decreases were smaller in lower tract infections. Plasma magnesium was decreased and then increased by lower tract infections, but upper tract infections had variable effects. In contrast to earlier reports, acute phase E. acervulina, E. brunetti, and E. tenella infections decreased sodium plasma concentrations. Plasma potassium concentrations were variable, but increases were associated with the induction phases of E. necatrix and E. brunetti infections.

Avian toxoplasmosis: experimental infection of chicken and pigeon

Two groups of 13 new-laying hens each were infected by crop-route with 5000 and 50,000 infective oocysts of T. gondii. Four groups of 5 pigeons each were inoculated by crop-route with 50, 500, 1000 and 5000 infective oocysts. To each group of infected birds suitable controls were added. Hens from the experiment with 5000 infective oocysts were apparently resistant to the infection and they had no clinical signs in the succeeding 40 days p.i. Hens from the experiment with 50,000 infective oocysts showed an egg-drop and mortality in embryonated eggs, especially during the first 2 weeks p.i. Isolation of the parasite was unsuccessfully attempted from 720 embryonated eggs, produced by infected groups, and tested on various days p.i. and at different stages of infection. The parasite was isolated from the brain, heart, liver, spleen and lung of infected birds 7 and 15 days p.i.; 40 days p.i. it was evident only in brain and heart. IgG onset and mean course were monitored by ELISA and high titers were reached by both groups. Pigeons from groups 500, 1000 and 5000 developed rapidly progressive clinical signs as diarrhea, trembling, incoordination, torticollis and death. They had enlargement of liver and spleen and focal necrosis, nodular features in the crop. Pigeons from expt 50 had no clinical signs in spite of the presence of the parasite in their organs for over 45 days p.i. Parasite was isolated from brain, heart, liver, spleen, lung, kidney, crop and muscles from all infected groups. Histopathological and ultrastructural features revealed the presence of multiplying tachizoites even within cells of the crop. Seroconversion, as monitored by ELISA, was recorded in all infected groups although high ELISA-titres were never reached. One of the negative controls from expt 5000 developed specific antibodies but the parasite was not isolated from its organs.

Class-specific circulating antibodies in infections with Eimeria tenella

Using a three-layer immunofluorescent test, class-specific, parasite-specific circulating antibody responses to Eimeria tenella were investigated following oocyst infection, drug-truncated oocyst infection and the injection of non-living antigens. Following all three means of antigenic stimulation, IgG, IgM and IgA antibodies were detected. The response to drug-truncated infections was dose-dependent. The sequence of appearance of antibody was IgM, IgA, IgG, whilst the relative quantities were IgG greater than or equal to IgM greater than IgA.

Does Plasmodium gallinaceum induce relapse of Eimeria acervulina infection in chickens?

An experiment was carried out to test the hypothesis that chickens previously infected with Eimeria acervulina, but having ceased producing oocysts, recommence E acervulina oocyst production when infected with Plasmodium gallinaceum. No relapse of coccidiosis was caused by the malarial infection. Subsequent treatment with the immunosuppressant betamethasone of the control chicks infected with E acervulina only did not reveal any occult coccidial infection. The results are critically compared with previously published results which apparently supported the hypothesis.

Connections between Ascaridia galli and the bacterial flora in the intestine of hens

Parasitological dissections of 502 intestinal tracts of hens deriving from big private chicken-farms have been done. In the jejunum of 146 hosts (ext. 29.1%) from 1 to 21 individuals of A. galli were detected. Using bacterial selective media and biochemical tests, the microorganisms from the hen's intestinal tracts as well as from the cuticle surface of the nematodes were identified. Among them were: grampositive (+) Lactobacillus, Bacillus, Staphylococcus, Streptococcus, Micrococcus, Sarcina, Clostridium, Corynebacterium; gramnegative (-) Enterobacteriaceae, Pseudomonas, Pasteurella, and fungi Candida and others. The lower frequency of microorganisms and the smaller amount of bacteria in the intestinal content in infected hens than in uninfected show that A. galli has antibacterial properties.