Efficacy of a herbal product against Histomonas meleagridis after experimental infection of turkey poults

Histomoniasis (infectious enterohepatitis, blackhead) is caused by the protozoan parasite Histomonas meleagridis (H. meleagridis). After the ban of all prophylactic and therapeutic drugs in the European Union, histomoniasis is increasingly responsible for considerable economic problems to the poultry industry. The aim of this study was to investigate the effect of a herbal product with extracts from cinnamon, garlic, lemon, and rosemary on H. meleagridis in turkey poults in vivo. For this purpose, 60 two-week-old poults were divided into three groups. Group 1 received the herbal product in the feed six days before infection and in water three days before infection, then in feed and drinking water until the end of the experiment. Groups 2 and 3 were left untreated. At week 3 of age, Groups 1 and 2 were infected intracloacally with H. meleagridis. Three weeks after infection the surviving birds were euthanized and examined for pathological lesions. Mortality was 20% in Group 1 and 50% in Group 2. There were no deaths in Group 3. DNA of histomonads was detected in all examined caeca and livers of the dead birds, but was not detected in any examined organ of the surviving birds of all groups. There was no noticeable difference in the lesion scores of the dead birds between the groups. The surviving birds of all groups did not show lesions post mortem. Since all effective prophylactic and therapeutic drugs against histomoniasis were banned in the EU, under given conditions the investigated herbal product seems to be an effective alternative for the reduction of mortality in turkeys caused by histomoniasis.     

Pilot study on the efficacy of paromomycin as a histomonostatic feed additive in turkey poults experimentally infected with Histomonas meleagridis

Paromomycin is an aminoglycoside antibiotic with activity against protozoa. Currently, paromomycin is registered for food producing animal species. In a pilot study we evaluated the efficacy of different doses of paromomycin in the feed against Histomonas meleagridis in experimentally challenged turkey poults. Groups consisting of 30 birds each were given feed with 100, 200 and 400 ppm paromomycin, respectively, starting on day 1 through to day 42. One group of 30 birds was left untreated. On day 21 all birds were infected intracloacally with H. meleagridis. Additionally, 10 birds were kept as a non-infected and non-treated control group. Before the challenge there was no significant difference between untreated and treated groups with regards to feed consumption and feed conversion rate. After the challenge, mortality was 80% in the infected non-treated birds. In the treated groups the mortality rate was 73.3%, 43.3% and 20%, respectively. No histomonal DNA was found in caeca and livers of the surviving birds. In addition, higher doses of paromomycin (200 and 400 ppm) led to reduced counts of Clostridium perfringens in the droppings. In conclusion, a prophylactic application of paromomycin as a feed additive was effective against the challenge with H. meleagridis under experimental conditions.     

Experimental Histomoniasis in the Guinea Fowl,Numida meleagris*

Guinea fowl were inoculated rectally with Histomonas meleagridis to produce histomoniasis. The birds were infected readily by this unnatural route. Severe cecal involvement was frequent and long-lasting but liver lesions and death were rare. Turkeys given the same inoculum had high levels of liver involvement and mortality. Guinea fowl responded much less severely to infection with H. meleagridis when infected by a natural route (ingestion of a vector) rather than by rectal inoculation. Thus, naturally acquired infections with H. meleagridis appear to be of small consequence in the guinea fowl.     

Blood Protozoa of Wild Turkeys in Florida*

From 1969 through 1972, 605 wild turkeys (Meleagris gallopavo Linnaeus) from 10 localities in Florida were examined for blood protozoans. The prevalence in turkeys more than a month old was 84% for Haemoproteus meleagridis Levine, 1961 and 72% for Leucocytozoon smithi Laveran and Lucet, 1905. Sixty-three percent of the birds were infected by both parasites. Infections were most prevalent in juveniles 8–12 months of age. No infection of H. meleagridis or L. smithi was found in 111 poults younger than 35 days. Prevalences were similar in both sexes. Haemoproteus meleagridis was more prevalent (87%) in the southern part of the state; L. smithi was more prevalent (75%) in the north. The prevalence of H. meleagridis did not change during the 4 year period, but L. smithi decreased markedly in 1971, a year of low rainfall. None of the 605 blood films was positive for Plasmodium, but 24 (75%) of 32 blood samples were found by subinoculation technics to be positive for a species of Plasmodium morphologically similar to P. durae Herman, 1941. No trypanosomes were seen on the 605 blood films or in bone marrow cultures (saline-neopeptone-blood) made from 11 turkeys.     

Dynamics of protozoan population density, plasma glutamic oxalacetic transaminase and plasma bilirubin concentrations during histomoniasis in turkeys

Density of populations of Histomonas meleagridis in ceca of infected turkeys was recorded daily for the first 17 days postinoculation with 20,000 protozoa. The major features of population growth were a 5-day lag period followed by rapid growth and plateau on the order 10⁷ protozoa/ml. Protozoan populations in hosts that failed to develop clinical histomoniasis remained close to the lag period density for the duration of the experiment. Plasma concentrations of glutamic oxalacetic transaminase (GOT) were found to be only weakly associated with the occurrence of clinical symptoms. Those results suggest that clinical symptoms are a cecal phenomenon, dependent on high population density of H. meleagridis. Evidence for elevation of both conjugated (direct) and protein-bound (indirect) bilirubin during histomoniasis suggests hemolytic jaundice, complicated with liver daage.     

Heterakis gallinarum in the guniea fowl, Numida meleagris: survival and comparative potential for transmitting Histomonas meleagridis

As measured by survival to maturity, size, and reproductive potential, Heterakis gallinarum thrived in young guinea fowl, unless concurrent infections with Histomonas meleagridis caused severe cecal lesions. Eggs of heterakids recovered from guinea fowl transmitted H. meleagridis to young turkeys. The young guinea fowl seems to be somewhat less important than the young New Hampshire chicken in spreading histomoniasis, but considerably more important than the young turkey.     

Infectivity of Histomonas meleagridis of Cecal and Liver Origins Compared

SYNOPSIS. Turkey poults were inoculated rectally with 100, 1000, 10,000, or 100,000 Histomonas meleagridis from the ceca of a group of experimentally infected turkeys. Other poults were given the same numbers of histomonads from an infected liver from the same group of source birds, Comparisons of the incidence of infection, liver involvement, mortality, and average survival time following these inoculations showed that organisms of cecal origin were about 100 times more effective in producing histomoniasis than were organisms of liver origin. It is suggested that this difference in infectivity resulted from heavy losses of histomonads of liver origin that were due to various selective processes.     

Immunological effect of Moringa Oleifera leaf extract on vaccinated and non-vaccinated Hubbard chickens experimentally infected with Newcastle virus

In veterinary medicine plant based medicine is achieving a huge importance worldwide. This research was subjected to rectify the hydrophilic Moringa Oleifera alcoholic leaves extract could improve the immune system in vaccinated and non-vaccinated broiler Hubbard chickens experimentally exposed to Newcastle disease (ND) virus. Seventy five chicks with age one day old were splitted randomly into five groups equally in distribution with fifteen chick in each group. Group I was untreated unvaccinated (control negative group) while group IV was infected group with NDV (control positive group). The experimental Groups II and V were given daily oral treatment of hydrophilic alcoholic leaves extract of M. oleifera at 200 mg/kg body weight until day 21 of age while groups III and V were ND vaccinated with La Sota strain of ND vaccines. The four groups (II, III, IV, V) were infected with ND virus velogenic strain (VNDV) on day 21. Following to infection, Monitoring of birds were done daily for clinical signs, postmortem examination, morbidity and mortality. Cellular, humeral immune response and phagocytic activity were evaluated and the data were statistically analyzed using (SPSS). Total and differential cell numbers as well as Haemagglutination inhibition (HI) titre increased in the extract treated and vaccinated group which give total protection against NDV much more than treated and unvaccinated group. As a result it could be recommended to use M. Olifera extract from the first day of rearing in Hubbard chicken with ND vaccination program as a prophylactic treatment in protection of birds against ND infection.     

Effect of Bile on Infectivity of Histomonas meleagridis of Liver Origin

SYNOPSIS After 30 min exposure to fresh turkey bile at 99 F, 100,000 Histomonas meleagridis of turkey liver origin failed to infect any of 20 poults inoculated rectally. Only one of 20 poults similarly inoculated with histomonads exposed to fresh turkey bile for only 5 min at 99 F became infected. Fifteen of 20 poults became infected following rectal inoculation with 100,000 H. meleagridis of liver origin held in physiologic saline for 30 min at 99 F. All infected birds developed liver lesions and died. Altho H. meleagridis was very abundant in the livers of all potential donor poults and all infected recipient poults, histomonads were never found in the gall bladders of any of these birds. In some such birds, a few apparently degenerating histomonads were detected in the duodenum near the entrance of the bile ducts. Histomonads of liver origin are regarded as of little or no consequence in the transmission of this protozoon.     

The effect of dietary methionine levels on fattening performance and selected blood and tissue parameters of turkeys

A total of 490 eight-week-old female Hybrid Converter turkeys (body weight 4.11 ± 0.03 kg) were divided into 5 groups with 7 replicates of 14 birds each. For 8 weeks, basal diets were supplemented with methionine (Met) at following levels (weeks 9–12/weeks 13–16 of age): Group 1 – 0.34/0.29%, Group 2 – 0.39/0.34%, Groups 3 and 4 – 0.45/0.38% and 0.51/0.41%, respectively, Group 5 – 0.58/0.47%. Only in the first feeding phase the body weight gain (BWG) was affected by Met levels with the significantly highest BWG in Group 3. No treatment effects were found for feed conversion ratio, carcass yield, carcass composition and meat colour. The blood superoxide dismutase activity was significantly highest in Groups 2 and 3. The concentrations of reduced glutathione in the liver were linearly increased (p = 0.018), whereas the ratio of reduced glutathione to oxidised glutathione was highest in Group 3 (quadratic contrast, p = 0.004). It can be concluded that turkeys from Group 3 (Met levels age depending 15% and 10% above recommendations by NRC) were characterised by a well-balanced physiological response. Attention should be paid to the immune response of birds to higher dietary Met levels: plasma IgA concentrations decreased, whereas IL-6 and TNF-α levels increased in turkeys fed diets with the highest Met content.     

A novel multi‐strain probiotic and synbiotic supplement for prevention of Clostridium difficile infection in a murine model

The protective effect of a multi‐strain probiotic and synbiotic formulation was evaluated in C57BL/6 mice infected with Clostridium difficile (CD) NAP1/027. Antibiotic‐treated mice were divided into the following four groups: Group 1, fed with a synbiotic formulation consisting of Lactobacillus plantarum F44, L. paracasei F8, Bifidobacterium breve 46, B. lactis 8:8, galacto‐oligosaccharides, isomalto‐oligosaccharides, and resistant starch; Group 2, fed with the same four probiotic strains as Group 1; Group 3, fed with the same prebiotic supplements as Group 1 for 7 days before CD infection; and Group 4 (control group) antibiotic treated and infected with NAP1/027 strain. Feces and cecal contents were collected for microbial cell viability, quantitative PCR (qPCR), toxin analyses and histopathology. Synbiotics‐ and probiotics‐fed mice showed a significant increase in total bifidobacteria (P < 0.05). The total lactobacilli count was increased in Group 1. Tests for cecal toxins were negative in Group 2 mice, whereas one sample each from Group 1 and 3 was positive. qPCR of cecal contents showed significant reduction in NAP1/027 DNA copies in Groups 1 and 2 and significantly higher numbers of B. breve 46, L. plantarum F44, and L. paracasei F8 in Groups 1 and 2 (P < 0.05); these changes were much less pronounced in Groups 3 and 4. Our findings indicate that the newly developed synbiotic or multi‐strain probiotic formulation confers protection against NAP1/027 infection in C57BL/6 mice. This holds promise for performing human studies.     

Dopamine and mesotocin neurotransmission during the transition from incubation to brooding in the turkey

We investigated the neuroendocrine changes involved in the transition from incubating eggs to brooding of the young in turkeys. Numbers of mesotocin (MT; the avian analog of mammalian oxytocin) immunoreactive (ir) neurons were higher in the nucleus paraventricularis magnocellularis (PVN) and nucleus supraopticus, pars ventralis (SOv) of late stage incubating hens compared to the layers. When incubating and laying hens were presented with poults, all incubating hens displayed brooding behavior. c-fos mRNA expression was found in several brain areas in brooding hens. The majority of c-fos mRNA expression by MT-ir neurons was observed in the PVN and SOv while the majority of c-fos mRNA expression in dopaminergic (DAergic) neurons was observed in the ventral part of the nucleus preopticus medialis (POM). Following intracerebroventricular injection of DA or oxytocin (OT) receptor antagonists, hens incubating eggs were introduced to poults. Over 80% of those injected with vehicle or the D1 DA receptor antagonist brooded poults, while over 80% of those receiving the D2 DA receptor antagonist or the OT receptor antagonist failed to brood the poults. The D2 DA/OT antagonist groups also displayed less c-fos mRNA in the dorsal part of POM and the medial part of the bed nucleus of the stria terminalis (BSTM) areas than did the D1 DA/vehicle groups. These data indicate that numerous brain areas are activated when incubating hens initially transition to poult brooding behavior. They also indicate that DAergic, through its D2 receptor, and MTergic systems may play a role in regulating brooding behaviors in birds.     

The effect of eubiotic feed additives on the performance of growing pigs and the activity of intestinal microflora

The aim of this study was to compare the effect of probiotic bacteria, prebiotics, phytobiotics and their combinations on performance and microbial activity in the digestive tract of growing pigs. The experiment was conducted over 28 d on 48 male pigs of about 12 kg body weight (BW), which were allocated to following treatments.: (1) Control Group (Con) without additive, (2) Group I, addition of a prebiotic (inulin), (3) Group Ph, a phytobiotic (herbal water extracts), (4) Group P, a probiotic composed of four strains of lactic acid bacteria, (5) Group PhP, phytobiotic and probiotic bacteria and (6) Group PhPI, a phytobiotic, probiotic bacteria and a prebiotic. Animal performance was recorded and at d 28 six pigs from each group were euthanised to collect digesta samples. In all groups except for Group I, diarrhoea incidents were observed. Groups Ph and P had significantly higher daily gains and final BW, and Group Ph utilised feed better than other groups. The pH of ileal digesta was significantly lower in Group PhPI. In the caecal digesta of Groups I, P and PhP, the pH level was lower than in the other groups but dry matter contents was significantly higher in Groups Con and I. The short-chain fatty acids and particular acid content differed significantly only in the colonic digesta. The yeast and mould numbers in caecal digesta was highest in Group Con. No treatment effects were observed for the number of lactic acid bacteria, coli group bacteria or Clostridium. However, the observed significantly higher number of total bacteria suggests that a multi-component eubiotic treatment changes the bacterial composition and distribution more effectively. Our findings indicated that all used additives changed the intestinal microflora, but the multi-component eubiotics were not beneficial as feed additives offered separately. Moreover, supplementation of phytobiotics and probiotic bacteria also improved the animal performance significantly.     

Population genetics of Cryptosporidium meleagridis in humans and birds: evidence for cross-species transmission

Population genetic studies have been used to understand the transmission of pathogens in humans and animals, especially the role of zoonotic infections and evolution and dispersal of virulent subtypes. In this study, we analysed the genetic diversity and population structure of Cryptosporidium meleagridis, the only known Cryptosporidium species that infects both avian and mammalian hosts and is responsible for approximately 10% of human cryptosporidiosis in some areas. A total of 62 C. meleagridis specimens from children, AIDS patients, and birds in Lima, Peru were characterised by sequence analysis of the ssrRNA gene and five minisatellite, microsatellite and polymorphic markers in chromosome 6, including the 60 kDa glycoprotein (gp60), 47 kDa glycoprotein (CP47), a serine repeat antigen (MSC6-5), retinitis pigmentosa GTPase regulator (RPGR) and thrombospondin protein 8 (TSP8). The multilocus sequence analysis identified concurrent infections with Cryptosporidium hominis in four AIDS patients and three children. Unique subtypes of C. meleagridis ranged from eight at the gp60 locus (gene diversity –Hd = 0.651), three at the RPGR (Hd = 0.556), three at the MSC6-5 locus (Hd = 0.242), two at TSP8 (Hd = 0.198), to one at CP47 (monomorphic), much lower than that of C. hominis in the same area. Intragenic linkage disequilibrium was strong and complete at all gene loci. Intergenic linkage disequilibrium was highly significant (P < 0.001) for all pairs of polymorphic loci. Two major groups of subtypes were seen, with most subtypes belonging to group 1. Within group 1, there was no clear population segregation, and two of the 14 multilocus subtypes of C. meleagridis were found in both AIDS patients and birds. We believe that these results provide the first evidence of a clonal population structure of C. meleagridis and the likely occurrence of cross-species transmission of C. meleagridis between birds and humans.     

Characterization of temperature-sensitive mutants of bacteriophage PM2: Membrane mutants

Summary In an effort to understand the genetic regulation of membrane morphogenesis, twenty-nine temperature-sensitive mutants of the membrane-containing bacteriophage PM2 were isolated. Characterization at restrictive temperature revealed groups showing no lysis (Groups I–IV), partial lysis (Groups V–VIII), and full lysis (Groups IX–XII) of the host Pseudomonas BAL-31. When the cell lysis data are considered in conjunction with data on stimulation of viral DNA synthesis, at least six mutant groups are defined. Analysis by gel electrophoresis of the pattern of viral proteins synthesized under restrictive conditions further divides the mutants into twelve groups. Temperature shift experiments delineate early, intermediate and late mutants. Complementation data support some of these groupings. The observed low levels of complementation and recombination are discussed in terms of gene product/genome restriction, bound to the membrane at the site of infection.It is of particular interest to membrane morphogenesis that under restrictive conditions late mutants in Groups II, III and IV make empty-appearing vesicles inside the cell that are the size of virus membranes as seen in thin sections of cells in the electron microscope. Mutants ts 1 (Group II) and ts 12 (Group III) show defects in their ability to incorporate into membranes viral structural proteins sp 13 and sp 6.6. The possibility is discussed that either of these proteins control the size and shape of the viral membrane.     

Increased primary resistance to recommended antibiotics negatively affects Helicobacter pylori eradication

Objective. To evaluate the efficacy of two commonly employed treatments for Helicobacter pylori infection and the impact of bacterial resistance to antibiotics on eradication rate. Methods. Ninety‐two consecutive H. pylori‐positive patients with active peptic ulcer disease were randomly enrolled to receive a 7‐day treatment with either lansoprazole 30 mg plus amoxicillin 1 g and clarithromycin 500 mg [all twice a day (b.i.d.), Group A, n = 46]; or bismuth subcitrate 125 mg four times a day (q.i.d.) plus tetracycline 500 mg q.i.d and furazolidone 200 mg b.i.d. (Group B, n = 46) H. pylori status was reassessed 30 days after completion of the therapy and bacterial resistance to the antibiotics was investigated using an in vitro assay. Results. Five patients from each study group were lost to follow up. Both treatments resulted in similar H. pylori eradication rate: 66–60% (per protocol), 59–52% (intention‐to‐treat) in Groups A and B, respectively (non significant). However, eradication improved to 79% in the absence of H. pylori resistance to clarithromycin or amoxicillin. Conclusion. Primary resistance to clarithromycin or amoxicillin may underscore a potentially serious problem for the eradication of H. pylori infection. Testing for bacterial resistance may become necessary to improve therapeutic efficacy.     

In ovo silver nanoparticle supplementation for improving the post-hatch immunity status of broiler chickens

Silver nanoparticles (AgNano) are known for their unique physical, chemical and biological properties, enabling cell penetration and anti-inflammatory response. In Experiment 1, the effect of an in ovo administration of AgNano (15 µg/egg; n = 360) at different incubation times (d 7 and d 18) on hatchability parameters was explored. In Experiment 2, post-hatch performance of broilers (42 d, n = 250) was studied after in ovo AgNano administration: Group T1 remained un-injected, Group T2 was the sham control and Groups T3, T4 and T5 were injected with 12.5, 25 and 50 µg AgNano, respectively, at 18 d of incubation. Chick weight, chick to egg weight ratio and hatchability as well average daily gain, average daily feed intake and feed conversion ratio were similar in all treatment groups. No variation was seen in the weight of thymus; however, the bursa and spleen weight was increased (p < 0.05) in Groups T4 and T5 in comparison to Group T1. The in vivo immune response to phytohaemagglutinin-P was increased in Group T3 in comparison to Groups T1 and T2 (p < 0.05), while the response to sheep red blood cells was increased in all AgNano-treated groups in comparison with Group T1 (p < 0.01). The expression of toll-like receptors 2 and 4 genes was up-regulated in AgNano groups in comparison with Groups T1 and T2 (p < 0.01). In summary, an in ovo supplementation of AgNano carried out at d 18 of incubation is effective and modulates the post-hatch immune response without affecting the hatchability, growth and other performance parameters in broilers.     

Production of gliotoxin during the pathogenic state in turkey poults byAspergillus fumigatus Fresenius

Turkey poults were given either of two different dosages of two different gliotoxin-producing strains ofAspergillus fumigatus. Infected lung tissue was examined postmortem for the presence of gliotoxin. Gliotoxin was found in lung tissue of ten poults infected with one strain and in seven of ten poults infected with the other strain. Concentrations of gliotoxin in the tissue exceeded 6 ppm in some of the infected tissues. The concentration of gliotoxin found in infected tissue did not appear to be correlated with the dosage of organism given. Considering the pathologic changes observed in turkey poults with aspergillosis and the production of gliotoxin during the pathogenic state in turkey poults, gliotoxin is considered likely to be involved in avian aspergillosis. Disclaimer: Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable.     

PLOIDAL CHANGES IN CLONAL CULTURES OF SPIROGYRA COMMUNIS AND IMPLICATIONS FOR SPECIES DEFINITION

A clonal culture of Spirogyra filaments of initially uniform width produced filaments of three additional significantly different widths. Group I filaments of the original clone were 30.9 ± 0.7 μm wide (mean ± SD, N = 50). Group I filaments produced Group II filaments (22.0 ± 1.1 μm) through vegetative growth and sexual reproduction. Zygospores from homothallic Group I filaments produced germlings representative of Groups I and II; zygospores from homothallic Group II filaments produced germlings representative of Group II only. Germlings of Groups III (27.7 ± 1.0 μm) and IV (44.9 ± 0.8 μm) were produced in the cross of I × II. Viable zygospores from homothallic Group III filaments were obtained. Cells of Group IV filaments were initially binucleate and did not conjugate. Of the six intergroup crosses possible, four resulted in conjugation-tube formation only; two crosses yielded zygospores (I × II and III × IV). Germlings from the successful cross of Groups III and IV produced filaments of all four groups. Chromosome counts were: Group I (24), Group II (12), Group III (18), and Group IV (24, one nucleus). Relative nuclear fluorescence values of mithramycin-stained DNA were (mean ± SD, N ≥ 30): Group I (11.1 ± 1.4), Group II (5.7 ± 0.7), Group III (8.8 ± 1.3), and Group IV (10.0 ± 0.9, one nucleus). Cytologically, Group II appears to be a diploid (2x), Group I a tetraploid (4x), and Group III a triploid (3x). Systematically, Groups I, II, and III key out to Spirogyra singularis, S. communis, and S. fragilis, respectively, using Transeau's mongraph of the family Zygnemataceae. These species are interpreted to represent a species complex of S. communis (whose name has priority) with the ancestral haploid (x = 6) missing.     

Immunity to exoerythrocytic forms of malaria. I. Course of infection of Plasmodium fallax in turkeys

Turkeys inoculated intravenously with Plasmodium fallax parasitized erythrocytes developed an initial parasitemia. After the parasitemia crisis, the number of exoerythrocytic forms increased and caused the death of the bird about a week later. When the size of the erythrocytic-form inoculum was decreased tenfold, the day of maximum parasitemia and the day of death due to a high level of exoerythrocytic-form parasitism was delayed approximately 1 day.Turkeys inoculated intravenously with exoerythrocytic forms obtained from erythrocyte-free tissue cultures of parasitized turkey embryo brain cells developed an initial exoerythrocytic-form infection. The growth of exoerythrocytic forms in the poults was not affected by daily drug treatment with chloroquine; the number of exoerythrocytic forms/1000 cerebral cell nuclei was not significantly different in chloroquinetreated or untreated poults. Following the exoerythrocytic-form crisis, the parasitemia increased for several days in nondrug-treated birds. In chloroquine-treated birds, the erythrocytic forms were only detected during the period when exoerythrocytic forms were prevalent. Erythrocytic-form schizonts were not observed in chloroquinentreated birds. The poults stopped gaining body weight when either the exoerythrocytic forms or the erythocytic forms were prevalent. A tenfold decrease in the exoerythrocytic-form inoculum size delayed the exoerythrocytic-form infection 1 day. The development of exoerythrocytic forms was not synchronous in turkeys inoculated with exoerythrocytic forms and examined prior to the exoerythrocytic-form crisis.