Pathology caused by three species of Eimeria that infect the turkey with a description of a scoring system for intestinal lesions.

Three-week-old turkey poults were infected with pure lines of three species of Eimeria (E. adenoeides, E. gallopavonis, and E. meleagrimitis) recently isolated from commercial turkey farms. The lines had been propagated from a single oocyst and identified by species-specific PCR amplification of the mitochondrial cytochrome c oxidase subunit I (COI) gene. Five to six days after infection their intestines were removed and examined for the presence of intestinal lesions. A description and review of the pathology caused by these parasites is provided, and a scoring system developed by which the severity of the lesions can be evaluated. The system is similar to that described by Johnson, J. and Reid, W. M. [1970. Anticoccidial drugs: lesion scoring techniques in battery and floor-pen experiments with chickens. Experimental Parasitology, 28, 30-36] for chickens in which a score of zero to four is assigned to lesions of increasing severity. The intestinal lesions observed here, and their assigned scores, are supported by representative illustrations. It is hoped that they may prove a useful tool for evaluating the pathology caused by E. adenoeides, E. gallopavonis, and E. meleagrimitis in the turkey.RESEARCH HIGHLIGHTSA scoring system has been developed for intestinal lesions caused by three species of Eimeria that infect the turkey.The lesions attributable to these species are illustrated.

Development of an in vivo model for Toxoplasma gondii infections in chickens and turkeys simulating natural routes of infection.

Turkeys and chickens were orally infected with tissue cysts (one mouse brain) or oocysts (103, 105 or 106 oocysts) of three T. gondii strains of the clonal types II and III (ME49, CZ-Tiger, NED) to investigate the influence of the applied T. gondii strain and infective doses on the distribution of T. gondii in several organs and tissues and the serologic response of chickens and turkeys. Organ samples from 16 different tissues, including heart, brain, muscles and gizzard were analyzed by PCR. Brain and heart were found most frequently positive for T. gondii DNA in both species, followed by gizzard. Serological analysis with kinetic ELISA for turkey samples and IFAT for chicken samples were performed once a week. In both species a dose-depending serological response was found. Turkeys seroconverted one week after infection with CZ-Tiger strain and medium and high doses of ME49 oocysts. In chickens, infection with medium and high doses of CZ-Tiger led to seroconversion one week p.i. Frequency of T. gondii positive organs showed a trend of a dose-effect in both species after infection with the type II strains. The NED strain showed low virulence in chickens and turkeys, demonstrated by clearly less T. gondii positive organs. Infection with tissue cysts of all three strains revealed T. gondii stages in tissues of turkeys and chickens. In conclusion, our data show a risk for human infection with T. gondii due to consumption of chicken and turkey meat.

Isolation and Genetic Characterization of Toxoplasma gondii from Tissues of Wild Turkeys (Meleagris gallopavo) in Pennsylvania.

Toxoplasmosis in wild turkeys (Meleagris gallopavo) is of epidemiological interest because turkeys feed from the ground, and detection of infection in turkeys indicates contamination by oocysts in the environment. During the 2018 spring hunting season in Pennsylvania, fresh (unfixed, not frozen) samples were obtained from 20 harvested wild turkeys and tested for Toxoplasma gondii infection. Hearts from all wild turkeys and skeletal muscle from 1 were bioassayed for T. gondii by inoculation in outbred Swiss Webster (SW) and interferon-gamma gene knockout (KO) mice. Antibodies to T. gondii were detected in 1:5 dilution of neat serum from 5 of 15 wild turkeys and in fluid from the heart of 1 of 4 wild turkeys with the modified agglutination test (MAT); neat serum was not available from 4 wild turkeys. Viable T. gondii was isolated from hearts of 5 wild turkeys, 1 with MAT of 1:10, 1 with MAT of 1:5, and 3 seronegative (MAT < 1:5). Toxoplasma gondii was isolated from both heart and skeletal muscle in the 1 wild turkey that had skeletal muscle submitted. The KO mice inoculated with tissue from all 5 infected wild turkeys died or were euthanatized when ill, 7-21 days post-inoculation (PI). Tachyzoites were detected in lungs of all KO mice, and the T. gondii strains were successfully propagated in cell culture. The SW mice inoculated with tissues of wild turkeys remained asymptomatic, and tissue cysts were seen in the brains of infected mice when euthanatized in good health at 46 days PI; 1 of the 2 SW mice inoculated with the heart of 1 turkey died on day 26, and tachyzoites were detected in its lung. Genetic typing on DNA extracted from culture-derived tachyzoites using the PCR restriction fragment length polymorphism with 10 genetic markers (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico) revealed that 4 isolates belonged to ToxoDB PCR-RFLP genotype #5 and 1 was genotype #216.

Cecal coccidiosis in turkeys: Comparative biology of Eimeria species in the lower intestinal tract of turkeys using genetically typed, single oocyst-derived lines.

Differentiating the Eimeria species causing cecal coccidiosis in turkeys is challenging. To obtain benchmark biological data for Eimeria gallopavonis Hawkins 1952 and Eimeria meleagridis Tyzzer 1929 and to support the stability of the species concept for each, genetically typed, single oocyst-derived lines of E. gallopavonis Weybridge strain and E. meleagridis USAR97-01 were used to redescribe the biological, pathological, and morphological features of these parasites. Oocysts of E. meleagridis and E. gallopavonis overlap in dimensions, but oocysts of the former have a single polar granule compared with multiple in the latter. Mature first-generation meronts of E. gallopavonis were observed histologically as early as 48 h post-inoculation alongside the villi in jejunum (before and after Meckel's diverticulum), ileum, cecal neck and rectum, but not cecal pouches. Three asexual cycles were observed suggesting that early workers apparently overlooked one asexual cycle. Examination of endogenous development of a culture labeled "Eimeria adenoeides Weybridge strain" suggested that this strain (found in a number of publications as a large oocyst strain of "Eimeria adenoeides") matched the species description of E. gallopavonis and so has been renamed herein. Macroscopic lesions induced by E. gallopavonis consisted of caseous material distally from posterior of the yolk stalk through the remaining intestinal tract, excluding the cecal pouches. For E. meleagridis, only the first asexual generation was observed outside of the cecal pouches within the jejunum around the yolk stalk. Second- and 3rd-generation asexual stages developed almost exclusively in the cecal pouches (but not cecal necks). Macroscopic lesions described for E. meleagridis were similar to those of E. adenoeides. Marked corrugation of the cecal serosal surface was observed. Cecal pouches contained creamy colored, caseous material varying from loose material to granular. Distinguishing features of the Eimeria species infecting the lower part of the small intestine are summarized in the present study, and new type specimens were designated for E. gallopavonis and E. meleagridis to provide a stable reference for future work with these parasites.

Long-term in vitro cultivation of Histomonas meleagridis coincides with the dominance of a very distinct phenotype of the parasite exhibiting increased tenacity and improved cell yields.

The majority of research on Histomonas meleagridis was performed in the first half of the last century, especially those on morphological aspects. In the present study identical monoxenic settings for cultures of the same H. meleagridis clonal strain in its virulent low passage and attenuated high passage form enabled a comparative analysis of parasite characteristics. For the first time, it could be shown that long-term in vitro cultivation led to a severe shift in cell morphology, with the occurrence of a very distinct phenotype expressing a flagellated and highly amoebic cell morphology. Furthermore, the attenuated parasites showed better growth rates and a higher tenacity when confronted with adverse conditions. During these experiments up to 100% of the parasites, both virulent and attenuated, assumed a completely rounded morphology elucidated by electron microscopy. The findings indicate that such previously reported cyst-like stages are a defence strategy of H. meleagridis, independent of the passage level in vitro and pathogenicity in vivo. In conclusion, long-term in vitro passaging of H. meleagridis led not only to an attenuation of the parasite, as previously demonstrated, but also to a shift in the parasite's phenotype regarding morphology, growth behaviour and a higher level of tenacity.

Coligranulomatosis (Hjärre and Wramby's disease) reconsidered.

Coligranulomatosis (Hjärre and Wramby's disease) is considered to be a disease of chickens, turkeys and partridges that occurs sporadically in individual, adult birds. Therefore, the condition is not of economic importance, but is of interest due to the similarity of its lesions to those of tuberculosis. In a number of cases the disease could be reproduced by inoculation via artificial routes of granuloma homogenate or Escherichia coli bacteria isolated from the lesions. Oral inoculations always failed. Occasionally, also serious outbreaks of granuloma disease have been reported in chickens, turkeys and quails. E. coli bacteria were either not isolated or isolated, but the disease could not be reproduced with the isolates, which means that the essence of Koch's postulates was not fulfilled. Also other evidence of causality was not presented. Therefore, these disease cases might have been wrongly diagnosed as coligranulomatosis. Instead they may have been caused by Tetratrichomonas gallinarum, a parasite, which has the ability to induce severe granulomatosis in chicken flocks as has been shown recently. It is concluded that whenever severe granuloma disease is observed in poultry flocks at a large scale and is thus economically relevant, T. gallinarum should be included and rank high in the list of differential diagnoses.

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

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

Reproduction, development and habits of the large turkey louse Chelopistes meleagridis (Phthiraptera: Ischnocera) under laboratory conditions / Reprodução, desenvolvimento e hábitos de Chelopistes meleagridis (Phthiraptera: Ischnocera) em laboratório

The bionomy of Chelopistes meleagridis off the host was observed with the aim of better understanding the aspects of this species' life cycle. For this purpose, C. meleagridis adults were collected and maintained under controlled conditions to reproduce (35°C and RH > 80%), with turkey feathers as the food source. From the offspring of these lice, the development of 150 individuals was observed from the egg to the adult phase. These eggs were divided into two groups of 75 each. After hatching, one group was given a diet composed of feathers while the other received feathers plus skin of the host turkey (Meleagris gallopavo). The “feather + skin” diet resulted in the greatest number of adults, so this diet was given to the next generation of lice reared in vitro, starting from the first instar, to observe their fertility, fecundity and longevity. High reproduction rates were found in relation to other lice of the Ischnocera sub-order, particularly the number of eggs per day and number of eggs produced per female over the lifetime (means of 2.54 and 26.61 eggs, respectively, for wild females and 2.11 and 29.33 eggs for laboratory-reared females). The inclusion of skin in the diet was a determining factor for development to the adult stage, since 48% of the lice fed this diet reached that stage, versus 1.3% that reached maturity fed only with feathers. The development time of the males and females was similar (mean of 29.38 days), without any difference in the sexual proportion of the adults.

A bionomia de Chelopistes meleagridis fora do hospedeiro foi observada com o objetivo de compreender aspectos relacionados ao ciclo de vida desta espécie. Para isto, adultos de C. meleagridis foram coletados e colocados em condições controladas (temperatura de 35°C e umidade relativa superior a 80%) para se reproduzir, oferecendo-se pena como alimento. Da prole destes adultos, foi observado o desenvolvimento de 150 indivíduos desde o ovo até a fase adulta. Para 75 destes, foi oferecida a dieta composta de pena, enquanto para os outros 75 a dieta foi composta de pena e pele do hospedeiro (peru, Meleagris gallopavo). Ao verificar que a dieta “pena + pele” foi a que resultou no maior número de adultos, foram observadas a fertilidade, fecundidade e a longevidade de piolhos criados in vitro desde o primeiro ínstar alimentados com esta dieta. Valores altos relacionados à reprodução desta espécie foram encontrados em relação a outros piolhos da subordem Ischnocera, destacando-se: número de ovos produzidos por dia e número de ovos produzidos por fêmeas durante a vida (médias de 2,54 e 26,61 ovos, respectivamente, para fêmeas selvagens e 2,11 e 29,33 ovos, respectivamente, para fêmeas criadas in vitro.). A inclusão de pele na dieta foi determinante para o desenvolvimento até o estágio adulto, uma vez que 48% dos piolhos alimentados com essa dieta atingiram a fase adulta. Quando foi oferecido apenas pena, 1,3% dos piolhos atingiram a maturidade. O tempo de desenvolvimento de machos e fêmeas foi semelhante (média de 29,38 dias) sem haver diferença na proporção sexual dos adultos.

Coccidia of turkey: from isolation, characterisation and comparison to molecular phylogeny and molecular diagnostics.

Coccidiosis is a disease caused by apicomplexan parasites of the genus Eimeria, which has a significant economic impact on poultry production. Multiple species infecting the turkey have been described; however, due to the general lack of unambiguous description, their identification and taxonomy is debatable. In this work, a systematic approach was taken to isolate, characterise and compare coccidian species in the turkey. Individual species were tracked according to their unique 18S ribosomal DNA sequence. The single-oocyst isolation technique and passaging of mixed species field isolates in selectively immunised birds enabled the derivation of pure species. Six distinct strains representing five eimerian species that infect the turkey were obtained. It appears highly probable that these species represent all species described in the past with the exception of Eimeria subrotunda. The species were analysed using both traditional methods and DNA sequencing. For each strain the oocyst morphology, prepatent period, gross pathology, pathogenicity, host specificity and endogenous cycle were studied. Antigenic similarity was investigated in multiple cross-immunity experiments. For identification and quantification of each individual species or strain, quantitative real-time PCR markers were also developed. Parallel characterisation of pure strains allowed comprehensive comparison with the original descriptions and assignment of correct species names. The species Eimeria meleagridis, Eimeria dispersa, Eimeria gallopavonis, Eimeria meleagrimitis and Eimeria innocua were identified. Comparison of our data with those of previous studies indicates that Eimeria adenoeides is most probably a synonym for either E. meleagridis or E. gallopavonis, or a description based on a mixture of these species, and thus nomen dubium. The species E. dispersa and E. innocua were also found to infect Bobwhite Quail. Phylogenetic reconstruction based on 18S rDNA and cytochrome c oxidase subunit I gene (COI) sequences showed that these two species form a distinct clade unrelated to other turkey coccidia and point to a polyphyletic origin of the species infecting the turkey.

Tissue tropism of Toxoplasma gondii in turkeys (Meleagris gallopavo) after parenteral infection.

Turkeys are known to be natural hosts for the zoonotic protozoan parasite Toxoplasma gondii. The objective of the present study was to gain further knowledge of possible predilection sites of T. gondii infection in this species after parenteral application of tachyzoites. A total of 38 turkeys were infected with different doses of T. gondii tachyzoites. Birds were killed either 6 to 8 or 10 to 12 weeks after the experimental infection. Fourteen different tissues per bird were investigated by a nested polymerase chain reaction (PCR) for the presence of the parasites' DNA. T. gondii DNA was found in any type of tissue analysed; in 86.1 % of all infected birds, at least one sample was tested positive. Over all intravenously infected birds, 15.4 % of all analysed samples contained T. gondii DNA. Most frequently affected tissues were liver (43.3 % positive samples), breast muscle (26.7 % positive samples) and heart (20.0 % positive samples), while the brain was less frequently positive (6.7 %). The number of positive tissues varied from zero to seven tissues per animal with at least one T. gondii-positive edible tissue sample in 80 % of all intravenously infected birds. Still, the results did not indicate defined target tissues or a cyst distribution pattern. Nonetheless, edible organs were most frequently parasitised. The number of positive findings did not differ between the early and the late examination time points. Therefore, a persistence of the tissue stages until the end of the study (12 weeks after infection) is concluded.

Description of the two strains of turkey coccidia Eimeria adenoeides with remarkable morphological variability.

Although oocyst morphology was always considered as a reliable parameter for coccidian species discrimination we describe strain variation of turkey coccidia, Eimeria adenoeides, which remarkably exceeds the variation observed in any other Eimeria species. Two strains have been isolated - the first strain maintains the typical oocyst morphology attributed to this species - large and ellipsoidal - while the second strain has small and ovoid oocysts, never described before for this species. Other biological parameters including pathogenicity were found to be similar. Cross-protection between these 2 strains in 2 immunization and challenge experiments was confirmed. Sequencing and analysis of 18S and ITS1 ribosomal DNA revealed a close relationship according to 18S and a relatively distant relationship according to ITS1. Analysis of 18S and ITS1 sequences from commercial turkey coccidiosis vaccines Immucox®-T and Coccivac®-T revealed that each vaccine contains a different strain of E. adenoeides and that these strains have 18S and ITS1 sequences homologous to the sequences of the strains we have isolated and described. These findings show that diagnostics of turkey coccidia according to oocyst morphology have to be carried out with caution or abolished entirely. Novel PCR-based molecular tools will be necessary for fast and reliable species discrimination.

Molecular characterization and phylogenetic analysis of Eimeria from turkeys and gamebirds: implications for evolutionary relationships in Galliform birds.

In order to determine the evolutionary relationships among Eimeria species that parasitize birds of the Galliformes, the 18s rDNA gene and a portion of the cytochrome oxidase subunit 1 (cox-1) were amplified from Eimeria species isolated from turkeys, chukars, and pheasants. The phylogenetic analysis of these sequences suggests that species infecting chickens are polyphyletic and, therefore, do not all share a direct common ancestor. Both the 18s rDNA and the cox-1 sequences indicate that Eimeria tenella and Eimeria necatrix are more closely related to Eimeria of turkeys and pheasants than to other species that infect the chicken. It is, therefore, likely that the chicken Eimeria spp. represent 2 separate ancestral colonizations of the gut, one of which comprises E. tenella and E. necatrix that infect the ceca, while the other includes Eimeria acervulina, Eimeria brunetti, Eimeria maxima, and Eimeria mitis, which infect the upper regions of the intestine.

Fine structure of the bird parasites Trichomonas gallinae and Tetratrichomonas gallinarum from cultures.

The trophozoites of Trichomonas gallinae and Tetratrichomonas gallinarum were studied by means of light and electron microscopy after cloning and cultivating them axenically. T. gallinae trophozoites varied in shape reaching from ovoidal to pyriform and had a size of about 7-11 microm. They were provided with four free flagella and a fifth recurrent one, which did not become free at the posterior pole. The nucleus was ovoid, had a size of about 2.5-3 microm, and was situated closely below the basal bodies of the flagella. The axostyle consisted of a row of microtubules running from the region of the apical basal bodies to the posterior end of the cell. In addition to flagellated stages, which contained food vacuoles, hydrogenosomes, a costa-like structure, and glycogen granules besides lacunes of endoplasmic reticulum, spherical, nonflagellated, and cyst-like stages occurred. The trophozoites of T. gallinarum appeared mostly pear-shaped and ranged in size from 6 to 15 microm. They had also four free anterior flagella and a fifth recurrent one, which became free at the posterior pole in contrast to that of T. gallinae. Another clearly visible difference to T. gallinae was the occurrence of a sphere of lacunes of the endoplasmic reticulum surrounding in a regular distance the nucleus with its typical perinuclear membranes. Furthermore, the food vacuoles appeared very large. However, both species clearly differed from the trophozoites of Histomonas meleagridis.

Two cestode species in Brazilian turkeys, meleagris gallopavo (Galliformes, Phasianidae): pathology induced by hymenolepis cantaniana and occurrence of raillietina tetragona

Duas especies de cestóides em perus, Meleagris gallopavo (Galliformes, Phasianidae), no Brazil: patologia induzida por Hymenolepis cantaniana e ocorência de Raillietina tetragona. A patologia induzida em perus pelo cestóide H. cantaniana é descrita, com dados sobre prevalência, intensidade media e amplitude das cargas parasitarias. H. cantaniana ocorreu com urna prevalência de 5.0 por cento nas 40 aves examinadas, com intensidade media de 17.5 e amplitude de 14-21 espécimes de cestóides. Não foram observadas lesões macroscópicas nos perus parasitados. As lesões provocadas por H. cantaniana eram representadas, principalmente, ou por múltiplos segmentos dos parásitos, acompanhados por discreta reação inflamatoria mista com a presera de células mononucleares e heterófilos, ou por severos processos inflamatorios transmurais, caracterizados pela presera de células mononucleares, ao longo das carnadas muscular e serosa das vilosidades e criptas intestinais. Estes representam os primeiros achados patológicos relacionados a presera de cestóides em perus a serem relatados no Brasil. Raillietina tetragona, não patogênica para as aves investigadas, ocorreu com baixa prevalência e amplitude de infecção de 2.5 por cento e 1-2 parásitos, respectivamente.

The pathology induced in turkeys (Meleagris gallopavo) by one cestode species Hymenolepis cantaniana is described together with data on prevalence, mean infection and range of worm burdens. H. cantaniana occurred with a prevalence of 5.0 percent in the 40 examined hosts in a range of 14-21 specimens and a mean intensity of 17.5. Gross lesions were not observed in the parasitized birds. Lesions due to H cantaniana mainly consisted of multiple segments of parasites, together with a mild mixed inflammatory reaction with the presence ofmononuclear cells and heterophils or severe transmural inflammatory processes, characterized by the presence ofmononuclear cells along the muscular and serosa layers of the intestinal villi and crypts. These are the first pathological findings related to the presence ofcestodes in turkeys to be reported in Brazil so far. Raillietina tetragona, not pathogenic to the present investigated turkeys, occurred with a low prevalence and range of infection of 2.5 percent and 1-2 worms, respectively.

Capillariid nematodes in Brazilian turkeys, Meleagris gallopavo (Galliformes, Phasianidae): pathology induced by Baruscapillaria obsignata and Eucoleus annulatus (Trichinelloidea, Capillariidae)

The pathology induced in turkeys (Meleagris gallopavo) by two capillariid nematodes, Baruscapillaria obsignata and Eucoleus annulatus is described together with data on prevalences, mean infection and range of worm burdens. B. obsignata occurred with a prevalence of 72.5 percent in the 40 examined hosts in a range of 2-461 nematodes and a mean intensity of 68.6, whereas E. annulatus was present in 2.5 percent of the animals, with a total amount of five recovered parasites. Gross lesions were not observed in the parasitized birds. Lesions due to B. obsignata mainly consisted of the thickening of intestinal villi with a mild mixed inflammatory infiltrate with the presence of mononuclear cells and heterophils. The lesions induced by E. annulatus were represented by foci of inflammatory infiltrate with heterophils in the crop epithelium and esophagus of a single infected female. These are the first pathological findings related to the presence of capillariid worms in turkeys to be reported in Brazil so far. Capillaria anatis, although present, was not pathogenic to the investigated turkeys.

Prevalence and pathology of the nematode Heterakis gallinarum, the trematode Paratanaisia bragai, and the protozoan Histomonas meleagridis in the turkey, Meleagris gallopavo

The prevalence of infection and associated pathology induced by two helminth and one protozoan species infecting Brazilian turkeys are reported. The intestinal nematode Heterakis gallinarum appeared with a prevalence of 70 percent in the infected birds, without gross lesions when not associated to the protozoan Histomonas meleagridis. Histological findings in the ceca were represented by the presence of H. gallinarum worms, intense chronic diffuse inflammatory processes with mononuclear and polymorphonuclear (heterophils) leucocyte infiltrations. The prevalence of the protozoan H. meleagridis associated to H. gallinarum was of 2.5 percent and microscopic examination revealed a severe inflammatory process in the liver and cecum with the presence of small clear areas with round eosinophilic parasites. Gross lesions were absent in turkeys infected with the renal digenetic trematode Paratanaisia bragai; the parasite was prevalent in 20 percent of the cases and cross-sections of the kidneys showed a remarkable distension of the collecting ducts with several worms in the lumen. The walls of the ducts presented a discrete heterophilic infiltrate among mononuclear cells.

PCR for the identification and differentiation of Histomonas meleagridis, Tetratrichomonas gallinarum and Blastocystis spp.

In the present investigation PCR assays were developed for the rapid detection and differentiation of two poultry flagellates: Histomonas meleagridis and Tetratrichomonas gallinarum as well as the protozoan microorganism: Blastocystis spp. The nucleotide sequences of the small subunit ribosomal RNAs were used for primer construction obtaining fragments which vary in size for each microorganism. The established PCRs were able to detect DNA obtained from one microorganism of T. gallinarum and Blastocystis spp. propagated in vitro, proving the high analytical sensitivity of the method. DNA isolated from 10 protozoa was sufficient to detect H. meleagridis. To assess specificity, each PCR assay was performed with DNA from either H. meleagridis and/or T. gallinarum and/or Blastocystis spp. as well as with DNA from several other protozoan parasites (Eimeria tenella, Toxoplasma gondii, Cryptosporidia spp., Trichomonas gallinae, Entamoeba invadens, Entamoeba ranarum), fungi (Aspergillus fumigatus, Candida albicans), bacteria (Staphylococcae, Streptococcae, E. coli, Clostridium perfringens, Camplyobacter jejuni, Proteus) and viruses (fowl adenovirus serotype 4, avian reovirus) as well as livers and caecal samples from turkeys and specified pathogen free (spf) chickens. No cross-reactions with any of these samples were observed with the primer sets for the detection of H. meleagridis and Blastocystis spp. The primers designed for the identification of T. gallinarum yielded a PCR product with DNA of Trichomonas gallinae that had the identical size as the amplicon obtained with DNA from T. gallinarum. However, no PCR products resulted from any of the other samples tested with these primers. Liver and caecal samples from turkeys and chickens from flocks with outbreaks of histomonosis also named as "histomoniasis" originating from geographically distinct regions were investigated with the established PCRs. This is also the first report about the detection of the nucleic acid of H. meleagridis, T. gallinarum and Blastocystis spp. nucleic acid in the livers and/or caeca of laying hens and turkeys obtained from field outbreaks. Hence, the established PCR assays proved to be a rapid and sensitive diagnostic tool for the direct detection and differentiation of H. meleagridis, T. gallinarum and Blastocystis spp. nucleic acid in organ samples of infected turkeys and chickens regardless of the geographic origin.

Cheilospirura hamulosa (Diesing, 1851) (Nematoda, Acuarioidea) in turkeys in Brazil: occurrence and pathology

Relata-se o primeiro caso de infecção de perus, Meleagris gallopavo, por Cheilospirura hamulosa no Brasil, com base no achado de três espécimes fêmeas de C. hamulosa, inseridos na submucosa da moela de um peru, retirado de um lote de 15 aves, provenientes de criadouros domésticos no estado de Minas Gerais. A ocorrência foi de 6,7 por cento. A ave parasitada não apresentava sinais clínicos. As lesões microscópicas da moela eram severas, caracterizando-se por intensos processos inflamatórios crônicos e difusos, com infiltrados mistos de granulócitos, estendendo-se à mucosa e às camadas musculares. Nessa área, foram observados fragmentos dos parasitos e perfuração da mucosa, com destruição das camadas musculares.

Characterization of a strain of Eimeria meleagridis from the turkey.

An isolate of Eimeria meleagridis Tyzzer, 1927 was obtained by harvesting oocysts from the ceca of a turkey from northwest Arkansas and a pure line was established by infecting birds with a single oocyst. Oocysts were first produced in the ceca of infected birds from 102 to 108 hr after inoculation and were of similar size (mean length X width, 24.9 X 17.0 microm) to those of Eimeria adenoeides Moore and Brown, 1951 and Eimeria gallopavonis Hawkins, 1952. The line was identified as E. meleagridis based upon the development of large schizonts in the midintestine, and small schizonts in the ceca. Two generations of large schizonts were found 48 and 72 hr after infection, and at least two generations of small schizonts were found from 60 to 108 hr after infection. An inoculum of 2 X 10(5) oocysts was found to cause a significant reduction in weight gain from days 0-3 and 0-6 after infection, suggesting that the significance of this species of Eimeria as a pathogen of turkeys should be reassessed.

Blackhead disease in turkeys: direct transmission of Histomonas meleagridis from bird to bird in a laboratory model.

The spread of Histomonas meleagridis infections through groups of turkeys in the absence of the cecal worm vector (Heterakis gallinarum) was studied in a battery cage model. Battery-reared poults were exposed at 2 wk of age by commingling with infected birds into cages that had the floor lined with paper. One treatment received no exposure, whereas other birds were commingled with two, three, or four birds/cage (25%, 37.5%, or 50%) inoculated per cloaca with cultured H. meleagridis (200,000/bird). Inoculated birds died at 7-13 days postinoculation (DPI) showing typical liver and cecal lesions of histomoniasis. By 14 DPI, 87.5% of the directly inoculated birds died or had severe lesions of histomoniasis. Turkeys commingled with two, three, or four infected birds became infected at the rate of 72%, 80%, or 75%, respectively. In another experiment, two birds/cage (25%) were inoculated with Histomonas from culture and allowed to commingle with other birds for 1, 2, 3, or 4 days. Two of 12 (16.7%) birds had minor cecal lesions after contact with inoculated birds for 1 day, but 87.5%-100% became infected if inoculated birds remained in the cage for 2-4 days. Contemporaneous inoculation with cecal coccidia (Eimeria adenoeides) as a predisposing factor in blackhead infections was studied using the model. Turkey poults directly inoculated with Histomonas were allowed to commingle for 5 days with uninoculated birds that had received inoculation with 0, 10(3), or 10(4) sporulated oocysts. The coccidian infection appeared to interfere with transmission of blackhead infection by 7 DPI, as suggested by lessened severity of cecal lesions and a lower percentage of infected birds. These studies confirm that histomoniasis is transmitted readily from directly exposed young turkeys to others in the absence of the cecal worm vector, and that this phenomenon can be reproduced in battery cages as an experimental model.