Mosquito transmission of wild turkey malaria, Plasmodium hermani.

Culex nigripalpus experimentally transmitted Plasmodium hermani, a plasmodium of wild turkeys (Meleagris gallopavo) in Florida. The mosquitoes were infected by feeding upon blood induced parasitemias in domestic turkey poults. The resulting sporozoites, transmitted by either mosquito bites or injection, produced malaria infections in domestic poults.     

Epizootiology of Plasmodium hermani in Florida: chronicity of experimental infections in domestic turkeys and northern bobwhites

A pen-reared northern bobwhite and a domestic turkey were infected with a strain of Plasmodium hermani obtained originally from a wild turkey in southern Florida. Blood films from these 2 birds were positive microscopically for 188 and 370 days postinfection (PI), respectively. Culicine mosquitoes (Culex nigripalpus and C. salinarius) were blood fed on the bobwhite and the turkey at different times during the infection and used to transmit the malaria to other bobwhites and turkeys up to days 298 and 473 PI, respectively. It was concluded that in nature, P. hermani could remain in a chronic phase in avian hosts for a year, or longer, allowing survival of the parasite between seasons of mosquito transmission.     

Absence of avian pox in wild turkeys in central Mississippi.

Eastern wild turkeys (Meleagris gallopavo silvestris) (n = 1,023), obtained during winter, spring, and summer from 1983 to 1988 on Tallahala Wildlife Management Area (TWMA) (Jasper County, Mississippi, USA) were examined for avian pox lesions. Domestic turkey poults (n = 152) maintained on the area for 1 to 2 wk periods from 1987 to 1989 also were examined. Neither wild nor domestic birds showed gross evidence of pox virus infection. This study indicated that avian pox was not endemic in wild turkeys at TWMA.     

Intestinal adaptation to diet in the young domestic and wild turkey (Meleagris gallopavo)

The short-term effects of diet on jejunal growth, alanine transport rate, and leucine aminopeptidase activity (LAP) were compared in the domestic and wild turkey poult. One-day-old poults of each strain were fed diets of high vs., low protein, with carbohydrate varied to maintain isocaloric conditions. Prior to feeding, relative jejunal mass and alanine transport rates were not significantly different in the two turkey strains, whereas LAP activity was 270% higher in wild poults. After feeding for 72 h, relative jejunal mass doubled in both turkey strains. In domestic turkeys, alanine transport rate and LAP activity were reduced by approximately 42% and 25%, respectively, in poults fed a 24% protein-69% carbohydrate diet vs. a 49% protein-35% carbohydrate diet. Analysis of the combined data from feeding experiments revealed that alanine transport rate was not correlated with total food, protein or lipid intake, but was negatively correlated with carbohydrate consumption (P<0.05). In wild turkeys, neither alanine transport rate nor LAP activity were altered by diet. These results reveal that domestic turkey hatchlings can modulate protein digestive and absorptive functions as protein/carbohydrate composition of the diet changes and suggest that high dietary carbohydrate down-regulates the intestinal alanine transporter.     

Precocial sexual behaviour in turkeys (Meleagris gallopavo L.)

Precocial struts were observed in 95 per cent of turkey poults of both sexes, wild and domesticated. In male turkey poults it occurred with about constant frequency up to day 100 (domesticated turkey: 0·6 struts per hr of observation time; wild turkeys: 0·1 struts per hr observation time) and dramatically increased in frequency after day 130, In female turkey poults, the incidence was much lower (about 0·01 struts per hr observation time) and did not shown any marked increase later on. Struts can be elicited by objects the poults are imprinted upon (mother hen, siblings, or human hand or foot in human imprinted poults). However, precocial struts can also occur spontaneously; i.e. in the absence of external stimulation by an imprinting object.     

The effect of dietary aflatoxin on wild turkey poults

Aflatoxins, toxic metabolites of Aspergillus flavus or Aspergillus parasiticus, cause poor feed utilization, decreased weight gains, depressed immune function, liver dysfunction, coagulation abnormalities, and death in a wide variety of species including humans. Conservationists have become concerned that increasingly popular wildlife feeding or baiting practices could expose wildlife to toxic amounts of aflatoxin-contaminated grains. In particular, the effects of aflatoxins on the wild turkey (Meleagris gallopova silvestris) are of concern because the conspecific domestic turkey is highly susceptible to aflatoxins. To evaluate the effect of dietary aflatoxin on wild turkeys, four groups of 4-mo-old wild turkeys were fed diets containing either 0, 100, 200, or 400 micrograms aflatoxin/kg feed for 2 wk in September and October 1996. Aflatoxin-fed poults had decreased feed consumption and weight gains as compared with control poults. Decreased liver-to-body weight ratios, liver enzyme alterations, slightly altered blood coagulation patterns, and mild histologic changes indicated low-level liver damage. Compromise of cell-mediated immunity was indicated by decreased lymphoblast transformation. The effects were apparent in all treatment groups to variable levels, but significant differences most often were found at 400 micrograms aflatoxin/kg feed. This study shows that short-term aflatoxin ingestion by wild turkeys can induce undesirable physiologic changes; therefore, exposure of wild turkeys to feeds containing aflatoxin levels of 100 micrograms aflatoxin/kg feed or more should be avoided.     

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.     

Rye Affects Bacterial Translocation,Intestinal Viscosity,Microbiota Composition and Bone Mineralization in Turkey Poults

Previously, we have reported that rye significantly increased both viscosity and Clostridium perfringens proliferation when compared with corn in an in vitro digestive model. Two independent trials were conducted to evaluate the effect of rye as a source of energy on bacterial translocation, intestinal viscosity, gut microbiota composition, and bone mineralization, when compared with corn in turkey poults. In each experiment, day-of-hatch, turkey poults were randomly assigned to either a corn or a rye diet (n = 0 /group). At 10 d of age, in both experiments, 12 birds/group were given an oral gavage dose of fluorescein isothiocyanate dextran (FITC-d). After 2.5 h of oral gavage, blood and liver samples were collected to evaluate the passage of FITC-d and bacterial translocation (BT) respectively. Duodenum, ileum and cecum gut sections were collected to evaluate intestinal viscosity and to enumerate gut microbiota. Tibias were collected for observation of bone parameters. Broilers fed with a rye diet showed increased (p<0.05) intestinal viscosity, BT, and serum FITC-d. Bacterial enumeration revealed that turkey poults fed with rye had increased the number of total lactic acid bacteria (LAB) in all three sections of the gastrointestinal tract evaluated when compared to turkey poults fed with corn. Turkey poults fed with rye also had significantly higher coliforms in duodenum and ileum but not in the ceca, whereas the total number of anaerobes increased only in duodenum. A significant reduction in bone strength and bone mineralization was observed in turkey poults fed with rye when compared with corn fed turkey poults. In conclusion, rye evoked mucosal damage in turkey poults that increased intestinal viscosity, increased leakage through the intestinal tract, and altered the microbiota composition and bone mineralization. Studies to evaluate dietary inclusion of selected Direct-Fed Microbial (DFM) candidates that produce exogenous enzymes in rye fed turkey poults are currently being evaluated.     

Hematozoan parasites of Rio Grande wild turkeys from southern Texas

One hundred twenty-three of 300 blood samples (41%) taken from Rio Grande wild turkeys (Meleagris gallopavo intermedia) from three locations in southern Texas (Welder Wildlife Refuge, Chaparrosa Ranch, and Campo Alegre Ranch) and subinoculated into domestic broad-breasted white turkey poults were positive for a Plasmodium (Novyella) sp. Analysis of blood films from 350 turkeys revealed Haemoproteus meleagridis in 76% of the birds. A significantly greater mean parasite intensity was observed in birds from Welder Wildlife Refuge. Birds from the Campo Alegre Ranch exhibited a significantly higher prevalence of H. meleagridis than birds from Chaparrosa. The Plasmodium sp. was infective for canaries (Serinus canaria), bobwhites (Colinus virginianus), and ring-necked pheasants (Phasianus colchicus), but would not produce infection in white leghorn chickens (Gallus gallus) or Coturnix quail (Coturnix coturnix). Attempts to infect Culex tarsalis and C. pipiens were unsuccessful. Asexual erythrocytic synchrony was not observed when blood-induced infections were monitored in two domestic turkey poults every 4 hr for 72 hr. Exoerythrocytic stages were not found upon examination of impression smears and tissue samples taken from brain, liver, spleen, kidney, lung, and bone marrow. The Plasmodium sp. is most similar morphologically to three species in the subgenus Novyella, P. hexamerium, P. vaughani, and P. kempi. The most striking similarities are to P. hexamerium, and involve mean merozoite number, erythrocytic schizont location, and vertebrate host susceptibility. It differs from P. vaughani in being able to infect turkeys and in type of parasitized erythrocytes. Differences to P. kempi include mean merozoite number, and ability to infect pheasants, and its inability to develop in C. pipiens and C. tarsalis.     

Prevalence of parasitism by Amblyomma americanum on wild turkey poults as influenced by prescribed burning.

Captive-raised eastern wild turkey (Meleagris gallopavo silvestris) poults were allowed to forage on either recently burned plots or on plots that had not been burned during the previous 3 years. Following a two hour exposure on the study plots, external parasites were recovered from all poults. The louse (Menacanthus stramineus) and the lone star tick (Amblyomma americanum) were the only parasites recovered. Fifty-nine poults exposed to the burned plots had a significantly (P less than 0.001) lower prevalence of A. americanum infestation than did 57 poults exposed to the unbured plots. Thirty-five percent of the poults exposed to the unburned plots were infested by A. americanum. A single A. americanum was recovered from one poult exposed to burned plots.     

Effect of turkey (Meleagridis gallopavo) breeder hen age and egg size on poult development. 1. Intestinal growth and glucose tolerance of the turkey poult

Three experiments were conducted to determine if turkey (Meleagridis gallopavo) hen age and egg weight affect poult intestinal development and glucose tolerance during the first week after hatching. Differences in glucose tolerance were not consistent across the experiments. In experiment 1, 4-day-old poults from the younger hens and lightest egg weight class had significantly greater fasting plasma glucose concentrations (P<0.04) and were also higher at 30 and 60 min post-injection of 250 mg glucose. In experiment 2, egg weight class had no significant effects on plasma glucose concentrations of 4-day-old poults (after injection of 2.5 mg glucose/g body weight). In experiment 3, plasma glucose concentrations were not different between groups at 0 or 30 min post-injection (3.75 mg glucose/g body weight), however, poults from the younger hens had 79–90 mg/dl higher plasma glucose concentrations 60 min post-injection versus poults from the older hens. Neither egg weight class or hen age consistently affected small intestinal weight, length, or density (g/cm) measures across experiments.     

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.     

Occurrence and seasonal transmission of hematozoa in wild turkeys

The occurrence and seasonal patterns of transmission of the blood protozoa of wild turkeys (Meleagris gallopavo silvestris) were studied at Tallahala Wildlife Management Area (TWMA) (Jasper County, Mississippi, USA). Blood smears obtained from wild turkeys in winter, spring and summer, and from sentinel domestic turkeys throughout the year were examined for Haemoproteus meleagridis and Leucocytozoon smithi. Whole blood from wild turkeys captured in summer was subinoculated into malaria-free domestic turkey poults and recipient birds were examined for Plasmodium spp. The prevalence of H. meleagridis and L. smithi were not different (P greater than 0.05) between adults and juveniles or between male and female turkeys in any season. Leucocytozoon smithi was not detected in poults in summer or in juveniles examined in winter. Sentinel studies and information from wild birds revealed that transmission of H. meleagridis and L. smithi did not overlap. Haemoproteus meleagridis was transmitted from May through November, while L. smithi was transmitted only from January through April. The onset of transmission of H. meleagridis coincided with peak hatching (mid-May) and brood-rearing (May-November) of turkey poults. Plasmodium spp. were not found in turkeys from TWMA (n = 27) nor in birds from three widely separated counties (n = 28) in Mississippi.     

Isolation and characterization of a herpesvirus from wild turkeys (Meleagris gallopavo osceola) in Florida.

Viral agents producing both a syncytial-type cytopathic effect and type A intranuclear inclusion bodies in vitro were isolated from the kidneys of five of 10 wild turkeys. A plaque assay system for viral infectivity was developed and used to characterize one of the wild turkey viruses (WTV). WTV replication was inhibited by 5-bromodeoxyuridine, indicating the virus contained DNA as its genetic material. Virus infectivity could be transferred only as viable whole cell preparations; one cycle of rapid freezing and thawing completely inactivated the virus. Typical herpes-like virions were found within the nuclei when cells infected with WTV were examined by electron microscopy. WTV had characteristics typical of the herpes group of viruses.     

Hematozoa of wild turkeys from the midwestern United States: translocation of wild turkeys and its potential role in the introduction of Plasmodium kempi

Twenty-three of 310 blood samples taken from live-trapped eastern wild turkeys (Meleagris gallopavo silvestris) from Missouri (USA), and hunter-killed birds from Wisconsin, North Dakota and Minnesota (USA), and inoculated into domestic broad-breasted-white turkey poults were positive for two species of Plasmodium. Twenty-one of the positive samples were infected with P. (Novyella) kempi, and two samples from Wisconsin were infected with P. (Giovannolaia) lophurae. Twenty percent of 310 blood smears were positive for Haemoproteus melagridis, while only 3% were infected with Leucocytozoon smithi. A statistically higher prevalence of Plasmodium spp. from 1983 to 1984 was observed in Wisconsin, and in the samples from Minnesota when compared with both Missouri and Wisconsin. Turkeys from Wisconsin and Minnesota had both a statistically higher prevalence and mean intensity of H. meleagridis than birds from Missouri. Evidence indicates that P. kempi has been introduced into other states along with the vertebrate hosts. It is suggested that greater care should be exercised when translocated wild turkeys are introduced into areas where there are other endangered or threatened avian species.     

Recent studies on aspergillosis in turkey poults

A review of the studies on aspergillosis in turkey poults at the National Animal Disease Center include limited field studies, pathogenicity studies, and vaccine development. Natural ventilation in turkey rearing houses was effective in reducing airborne propagules of four major fungal genera, but the effectiveness of ventilation appeared to be limited by the width of the building. Aspergillus fumigatus was more effective than A. flavus in producing mortalities in aerosol exposed poults. Toxigenicity of A. flavus did not enhance its pathogenicity, and no apparent aflatoxin production occurred during pathogenesis in infected turkey poults. Spores of A. fumigatus were disseminated quite rapidly in poults exposed to aerosols, and alveolar macrophages from respiratory lavages taken immediately after exposure contained spores of A. fumigatus. Vaccines produced from germlings of A. fumigatus and administered to turkey poults were the most efficacious of five vaccines tested against challenge exposure to aerosols of A. fumigatus spores.     

Comparison of media for isolation of poultry intestinal bacteria

The effects of medium composition, incubation temperature, and length of incubation were determined for recovery of the predominant intestinal bacteria from turkey poults. Incubation of recovery media at 41 degrees C resulted in significantly higher counts than at 37 degrees C. In 2- and 3-week-old turkey poults. RGCAP-30, RGCAP-10, and RGCA-30 gave the highest recoveries of cecal bacteria. M98-5 was less effective and brain heart infusion agar was definitely inadequate. However, there was no significant difference between RGCAP-30 and brain heart infusion agar for recovery of duodenal bacteria. In older birds (6 weeks of age), M98-5 was equal or superior to the RGCA-based media. The choice of a primary isolation medium is thus dependent on the site to be sampled and the age of the bird.     

Comparison of media for isolation of poultry intestinal bacteria.

The effects of medium composition, incubation temperature, and length of incubation were determined for recovery of the predominant intestinal bacteria from turkey poults. Incubation of recovery media at 41 degrees C resulted in significantly higher counts than at 37 degrees C. In 2- and 3-week-old turkey poults. RGCAP-30, RGCAP-10, and RGCA-30 gave the highest recoveries of cecal bacteria. M98-5 was less effective and brain heart infusion agar was definitely inadequate. However, there was no significant difference between RGCAP-30 and brain heart infusion agar for recovery of duodenal bacteria. In older birds (6 weeks of age), M98-5 was equal or superior to the RGCA-based media. The choice of a primary isolation medium is thus dependent on the site to be sampled and the age of the bird.     

Pathogenicity of Haemoproteus meleagridis (Haemosporina: Haemoproteidae) in experimentally infected domestic turkeys

Sporozoite-induced experimental infections of Haemoproteus meleagridis produced a moderate to severe myositis and significant effects on weight gain and growth in domestic turkey poults. Pathological effects occurred in both low- and high-dose infections (4,400 and 57,500 sporozoites, respectively). Low-dose birds weighed significantly less than controls at 3 wk postinfection (PI) when peripheral parasitemia reached a peak and had significantly shorter tarsometatarsal lengths at both 1 and 3 wk PI. High-dose birds were significantly lighter and smaller than control and low-dose birds throughout the course of the 8-wk study. Infected birds were not anemic in spite of high parasitemias that often exceeded 50% of circulating erythrocytes. The most serious pathological effects occurred prior to patency and were associated with development of megaloschizonts in skeletal muscle. Microscopic lesions in 4 high-dose birds that died between 19 and 22 days PI were characteristic of a severe, acute hemorrhagic myositis. Megaloschizonts were surrounded by a hemorrhagic inflammatory infiltrate composed of macrophages, heterophils, giant cells, and red blood cells. Muscle fibers adjacent to megaloschizonts were swollen, hyaline, and contained prominent calcium deposits. Other observations included enlargement of the spleen, deposition of pigment in macrophages of the lung and spleen, and secondary bacterial and fungal infections in the intestine and lungs. Necrotic and calcified muscle fibers and degenerating megaloschizonts were still present at 8 wk PI when the experiment ended. Our results demonstrated significant pathological changes in H. meleagridis-infected domestic turkeys that were associated primarily with preerythrocytic stages of development.     

Antigenic and genomic relationships among turkey and bovine enteric coronaviruses.

Antigenic and genomic relationships among tissue culture-adapted turkey enteric coronavirus (TCV) isolates, three strains of avian infectious bronchitis virus (IBV), and mammalian coronaviruses were investigated. Immunoblotting and immunoprecipitation experiments using polyclonal antisera showed that the four major structural proteins of TCV cross-reacted with the four homologous proteins of bovine enteric coronavirus (BCV), the N and M proteins of mouse hepatitis virus serotype 3, and the N protein of IBV. Close antigenic relationships between TCV and BCV were also established by seroneutralization and hemagglutination-inhibition. Of 49 monoclonal antibodies produced against either TCV or BCV, 11 differentiated the two viruses. Five of these monoclonal antibodies had neutralizing activities and were directed to either the peplomeric S (gp200-gp100) or hemagglutinin HE (gp140-gp65) glycoproteins. BCV cDNA probes tested on purified viral preparations and coronavirus-positive (by electron microscopy) fecal samples from diarrheic turkey poults confirmed the relatedness of TCV and BCV. The two viruses produced distinct cytopathic changes in HRT-18 cells in the presence of trypsin, whereas only TCV isolates were able to reproduce the clinical symptoms in turkey poults. Their matrix (M) proteins undergo different glycosylation processes.