Retrospective ultramicroscopic investigation on naturally cryptosporidial-infected commercial turkey poults

The morphometric characteristics and the ultramicroscopic findings of Cryptosporidium spp. at various stages of their life cycle in the intestinal and bursal epithelial cells of naturally infected 30-day-old commercial turkeys are reported. Small, sporulated oocysts, observed in the small intestinal content after flotation, were identified as Cryptosporidium meleagridis on the basis of morphometric characteristics (round in shape and 4.5-5.0 microm in size) and the small intestinal localization. Light section examinations revealed the presence of the protozoon in multiple organs, but its prevalence was highest in the intestinal and bursal epithelial cells. Ultramicroscopic studies on ileum and bursal samples showed the presence of all the life cycle stages in the microvillar brush epithelial cells in both the organs examined. On the basis of the comparison of the morphology and the sizes of the microorganisms parasitizing the ileum and the bursa, hypotheses are considered on the possible species involved.     

The prevalence of Chlamydia psittaci infections in Belgian commercial turkey poults

The prevalence of Chlamydia psittaci infections in Belgian commericial turkey poults was examined and a follow-up study of one Belgian turkey flock was performed. Sera were examined for the presence of anti-chlamydia antibodies by immunoblotting. Cloacal and conjunctival swab smears and lung impression smears were examined for the presence of chlamydial antigen using the IMAGEN Chlamydia immunofluorescence test. Anti-chlamydia antibodies were found in 90 of 100 sera collected at slaughter from turkeys raised during the summer of 1992. The following winter, 73 of 100 sera reacted positively. On all twenty farms examined during 1992, turkeys were positive for anti-chlamydial antibodies. During 1993, chlamydial antigen was detected in swabs from 20 of 40 slaughterhouse turkeys tested. Antigen was found more often in the cloaca than in the conjunctiva. Chlamydial antigen was detected in samples from each of the 4 farms examined. The follow-up study on a turkey farm, sampling the birds at weekly intervals from one week old until 12 weeks of age, revealed that chlamydial antigen and anti-chlamydial antibodies were present during the whole period. During 1994, chlamydial antigen was detected in 45 of 60 lungs from slaughterhouse turkeys from all of 6 farms. During 1995, chlamydial antigen was detected in 41 of 54 lungs of 6 week old commercial turkey poults. The results of the present study indicate that Chlamydia psittaci infections are highly prevalent amongst Belgian commercial turkey poults with apparently little seasonal or year-to-year variation and that turkeys can contract the infection at an early age.     

Rickets in turkey poults

Fifteen outbreaks of rickets were diagnosed in turkey poults in Saskatchewan between 1978 and 1981. No relationship to farm, source of poults, or source of feed was apparent. Most outbreaks started when the poults were between 10 and 14 days of age, and they had recovered by 28 days of age. Losses varied from 1% to 14% of poults started. Skeletal lesions were characteristic of a vitamin D or calcium deficiency. On the basis of chemical analyses, adequate levels of calcium and phosphorus and proper amounts of vitamin premixes were present in the feed, but in five outbreaks biological feed tests implicated feed as a causative factor. The severity of rickets in poults fed defective feeds was markedly reduced by providing the poults with extra vitamin D in the drinking water or by injection. Two premixes used in different feeds contained adequate available vitamin D on the basis of biological testing. In some of the outbreaks, the rickets may have resulted from inadequate distribution of vitamin D in the feed, destruction of vitamin D during feed processing, or some unknown factor in the feed interfering with vitamin D utilization.     

Salt poisoning in turkey poults

A 4% mortality in 5-to-11-day-old turkey poults was attributed to 1.85% sodium chloride in the feed. The syndrome included peracute respiratory distress, ascites, and sudden death that resembled peracute heart failure. Clinical signs were observed only in the final phase of the toxicity, but progressive histologic lesions were found. Live, apparently unaffected poults showed increases in intracellular glycogen and cytoplasmic granularity, loss of striation, and early mild intercellular myocardial edema; similar but more severe histologic lesions were seen in live, ascites-affected poults. The ascites-affected poults had hydropericardium and hydrothorax which seemed to develop just minutes before death. Ultrastructurally, focal areas of myocardial cells exhibited myofibrillar disarray, lysis of myofilaments, widened Z-bands, and dilation of sarcoplasmic reticulum.     

Turkey origin reovirus-induced immune dysfunction in specific pathogen free and commercial turkey poults

Recently, pathogenesis studies, using genetically distinct turkey-origin reoviruses (TRVs), revealed that poults infected with certain TRV isolates had moderate to severe bursal atrophy, suggesting virus-induced immune dysfunction. In order to characterize the effect of TRV infection on the turkey immune system, classical assays were undertaken to quantify the humoral and cell-mediated immune responses in small Beltsville and broad-breasted white poults infected with the TRV isolate NC/SEP-R44/03. A marked effect on the cutaneous basophil hypersensitivity response, and on the antibody response to Newcastle disease virus (NDV) exposure, was noted in commercial and specific pathogen free (SPF) poults inoculated with NC/SEP-R44/03 at three days of age. Moderate to severe bursal atrophy, similar to that noted previously in SPF poults, occurred in commercial poults inoculated at three days of age. This immune dysfunction and bursal atrophy was not present in commercial poults inoculated at three weeks of age.     

Furazolidone toxicity in neomycin-treated turkey poults

Furazolidone (FZ) toxicity was evaluated in turkey poults treated with neomycin at a dose of 20 mg/kg body weight for 5, 10, or 26 days. Neomycin treatment had no effect on FZ-induced anorexia, delayed the onset of altered electrocardiographic patterns by approximately 1 week, and did not significantly affect the development of FZ-induced cardiomyopathy. Data indicated that FZ toxicity is not significantly altered by the gut microflora.     

Enteric viruses in diarrheic turkey poults

Thirty-three intestinal samples from 10-to-21-day-old diarrheic turkey poults were examined for the presence of enteric viruses by electron microscopy. Samples originated from 32 flocks in six commercial operations located in six states. Mortality in these flocks ranged from 3 to 15%, and birds from recovered flocks varied greatly in size. Rotavirus-like agents (RVLA) were the most common viruses associated with diarrhea outbreaks in the flocks examined, occurring in five out of six operations. Other viruses detected either singly or in combination, in order of prevalence, were astroviruses, reoviruses, rotaviruses, enteroviruses, and adenoviruses. With the exception of RVLA and rotaviruses, the other viruses were identified solely on the basis of morphology. Salmonellae were isolated from only one of the intestinal samples. By electron microscopy, RVLA were morphologically indistinguishable from rotaviruses, occurring as both 55-nm single-shelled and 70-nm double-shelled particles. However, immune electron microscopy was useful for antigenic differentiation of these two viruses. Turkey rotaviruses reacted with antisera to porcine and bovine rotaviruses, whereas turkey RVLA did not. Neither turkey rotaviruses nor RVLA reacted with antisera to porcine para-rotavirus or an antigenically distinct bovine rotavirus (bovine rotavirus-like agent). Similarly, convalescent anti-turkey RVLA serum (from recovered specific-pathogen-free poults) reacted with homologous virus but did not react with mammalian or avian rotaviruses or reoviruses. Further, RVLA were found to possess RNA electrophoretic migration patterns unlike those of conventional rotaviruses or reoviruses. This trait was used as an additional means of differentiating these viruses.     

Otitis interna (labyrinthitis) associated with Salmonella enterica arizonae in turkey poults

Otitis interna was diagnosed in five 9-to-21-day-old turkey poults with clinical signs of paralysis, opisthotonus, torticollis, blindness, and increased mortality. Gross and microscopic lesions in the poults included omphalitis, typhlitis, hepatitis, meningoencephalitis, ophthalmitis, neuritis and ganglionitis of the vestibulocochlear nerve, and otitis interna. Salmonella enterica arizonae was isolated from the brains, eyes, intestines, yolk sacs, and livers of poults. Birds with otitis interna also had meningoencephalitis. It is most likely that the S. enterica arizonae infection spread from the brain to the internal ears through the vestibulocochlear nerve. This is the first documentation of otitis interna caused by bacteria in an avian species.     

Immediate hypersensitivity (anaphylaxis) response in uninfected and Alcaligenes faecalis-infected turkey poults

The immediate hypersensitivity (anaphylaxis) response in uninfected and Alcaligenes faecalis-infected turkey poults was studied. The optimum challenge dose of bovine serum albumin (BSA) to elicit an anaphylactic response was 40 mg/kg body weight, and the optimum poult age was 4 to 5 weeks. The response latency time was 7 days. The anaphylactic response was specific for the sensitizing antigen used. No differences were observed between A. faecalis-infected and uninfected poults in the immediate hypersensitivity response to BSA.     

Field studies with convalescent serum and infectious bursal disease vaccine to control turkey coryza

Convalescent serum given to 1-day-old poults delayed clinical signs of turkey coryza by several days and reduced mortality on infected farms. Turkey breeders immunized with cell-culture-adapted infectious bursal disease virus (IBDV) or turkey infectious bursal disease virus (TIBDV) had a marked increase in virus-neutralization (VN) antibody titers. The VN antibody titer was significantly higher in progeny poults than in poults from unimmunized breeders. Clinical turkey coryza and mortality was considerably less in poults from IBD- or TIBD-vaccinated breeders than in control poults. They also responded more favorably to hemorrhagic enteritis and fowl cholera vaccination.     

Vitamin A deficiency in turkey poults.

Vitamin A deficiency was diagnosed in a commercial flock of 13,000 4-6-week-old turkey poults in the summer of 2004. The birds were initially submitted for examination because of a 3% increase in the reported daily mortality of the flock. Clinically, affected birds had stunted growth and ruffled feathers, showed signs of incoordination, and were depressed. At necropsy, pale white pseudomembranous to mucoid material was observed on the mucosal surface of the tongue, oral cavity, portions of the esophagus, and the crop of some birds. Histologically, there was squamous metaplasia of the mucosal epithelium of the oral mucosa, esophagus, sinuses, nasal glands, bronchi, proventriculus, and the bursa of Fabricius. Vitamin A was not detected in the feed sample at a detection limit of 0.5 mg/kg. Serum vitamin A concentrations in 7 birds were very low and ranged from 0.05 to 0.1 mg/L. Vitamin A concentrations in livers were extremely low (0.1 mg/kg wet weight, 1/7 poults) or undetectable (< 0.1 mg/kg wet weight, 6/7 poults). A diagnosis of vitamin A deficiency was made based on gross and microscopic lesions and vitamin A concentrations in serum, liver, and feed. To the authors' knowledge, this is the first documented case of vitamin A deficiency in poults submitted from a commercial meat turkey producer comparatively depicting the gross and microscopic lesions with those found in other species of birds and mammals.     

Efficacy of lincomycin-spectinomycin water medication on Mycoplasma meleagridis airsacculitis in commercially reared turkey poults

A field trial was conducted to compare the efficacy of a combination of the drugs lincomycin and spectinomycin (LS) with Tylan (tylosin, T) against Mycoplasma meleagridis (MM) airsacculitis in 50,320 commercially reared turkey poults in Ohio. Both drugs were administered at 2 g per gallon of drinking water for the first 5 days of life. The poults were allotted randomly to two treatment groups with 8 or 5 replicates each. Initially, 250 poults were weighed, necropsied, and examined microbiologically and grossly for airsacculitis. At 3 weeks of age, 33 poults from each replicate were randomly selected, necropsied, and examined for airsacculitis. The data indicate that LS is superior to T as an aid in the control of MM airsacculitis in poults, as reflected by fewer air-sac lesions and greater improvement in weight gain (P less than 0.05).     

Specific mucosal IgA immunity in turkey poults infected with turkey coronavirus

The objective of this study was to elucidate the kinetics and magnitudes of specific IgA antibody responses in intestines of turkey poults infected with turkey coronavirus (TCV). Turkey poults were orally inoculated with TCV at 10 days of age. Intestinal segment cultures were administered for duodenum, jejunum, and ileum and the IgA antibody responses were analyzed at 1, 2, 3, 4, 6, or 9 weeks post-infection (PI) in two different experiments. The kinetics of virus-specific IgA antibody responses in duodenum, jejunum, and ileum were similar: gradually increased from 1 week PI, reached the peak at 3 or 4 weeks PI, and declined afterward. The virus-specific IgA antibody responses in duodenum, jejunum, and ileum showed negative correlation with duration of TCV antigen in the corresponding locations of intestine with Spearman's correlation coefficient of -0.85 (p=0.034), -0.74 (p=0.096), and -0.75 (p=0.084), respectively. Moreover, the virus-specific IgA antibody responses in serum were positively correlated with that of duodenum (coefficient=0.829, p=0.042), jejunum (coefficient=0.829, p=0.042), and ileum (coefficient=0.771, p=0.072) segment cultures, suggesting that the induction of specific IgA response in serum was predictive of an IgA response in intestine. The results indicate that intestinal mucosal IgA antibodies to TCV are elicited in turkeys following infection with TCV. The local mucosal antibodies may provide protective immunity for infected turkeys to recover from TCV infection.     

Characterization of turkey coronavirus from turkey poults with acute enteritis.

The present study was to characterize turkey coronavirus associated with turkey poult enteritis and mortality. Intestinal contents or intestines from affected turkey poults and inoculated turkey embryos contained coronaviruses as revealed by electron microscopy or were positive for turkey coronavirus by immunofluorescent antibody assay. Sucrose density gradient ultracentrifugation of the virus-containing intestinal homogenate yielded two opalescent bands corresponding to the buoyant densities of 1.14-1.15 and 1.18-1.20 g/ml, respectively. Coronaviral particles from intestinal contents or the sucrose density gradient preparation were mainly spherical in shape and had envelope and central depression. They were surrounded by a fringe of regularly spaced petal-shaped projections attached to the particles by a short stalk. Purified viruses hemagglutinated rabbit erythrocytes with a titer of 16. Major protein bands of purified viruses analyzed by SDS-PAGE were located at 200, 100-110, 50-60, and 30-35 kDa. The patterns of protein bands were consistent with those of Minnesota or Quebec turkey coronavirus isolates. A 568 bp nucleotide fragment of turkey coronavirus spike protein gene was amplified from RNA of inoculated turkey embryo intestine or purified virus. Sequence analysis of the 568 bp PCR product revealed high degree of identity with the corresponding spike protein gene sequence of human and bovine coronaviruses. The results indicated that turkey coronavirus was associated with turkey poults with acute enteritis.