Plasma pharmacokinetics of midazolam in chickens, turkeys, pheasants and bobwhite quail

In vivo plasma pharmacokinetics of midazolam hydrochloride (5 mg/kg i.v.) were determined in commercially raised broiler chickens, turkeys, ring-necked pheasants and bobwhite quail. Pharmacokinetic profiles of midazolam were similar for all four species, especially with regard to the area under the plasma drug concentration-time curve. Estimates of the half-life of elimination of midazolam were 0.42, 1.45, 1.90, and 9.71 h for turkeys, chickens, bobwhite quail, and pheasant, respectively. This was similar to the major metabolite (1-hydroxymidazolam). Elimination half-lives for 1-hydroxymidazolam were 1.35, 1.86, 1.97, and 13.97 h for turkey, chicken, bobwhite quail and pheasant, respectively. Elimination half-lives for 4-hydroxymidazolam were 0.76, 1.23, 2.85, and 13.82 h for chicken, turkey, pheasant, and bobwhite quail, respectively. In addition to traditional pharmacokinetic approaches to parameter estimation, a bootstrapping technique was employed to attempt to achieve more realistic approximations of the concentrations at later time-points.     

The homologous and interspecies transmission of Cryptosporidium parvum and Cryptosporidium meleagridis

Experimental infections have been performed in several mammals and birds to determine the host's specificity for Cryptosporidium parvum (of human and bovine origin) and for Cryptosporidium meleagridis (isolated from broiler chicken). The C. parvum infection (of human origin) was established also in calves (Bos taurus), lambs (Ovis aries), mice (Mus musculus), and rats (Ratus norvegicus), but not in broiler chickens (Gallus domestica). The C. parvum infection (of bovine origin), was achieved in calves, lambs, dogs (Canis familiaris), cats (Felis domesticus), rabbits (Orytolagus cuniculus), mice, rats, and guinea-pigs (Cavia porcelus) but not in broiler chickens. We have demonstrated that C. meleagridis can produce infection in broiler chickens and in 5 mammalian species (calves, pigs, rabbits, rats, mice) but not in guinea-pigs.     

Infectivity of Cryptosporidium sp isolated from wild mice for calves and mice

A study was conducted to determine the incidence of cryptosporidiosis in wild mice (Mus musculus) and the infectivity of oocysts from their feces for susceptible calves. The presence of oocysts and the duration of shedding of oocysts in the feces were evaluated in 115 wild mice. Approximately 30% of the mice shed Cryptosporidium sp oocysts, without evidence of clinical infection; recurrence of oocyst shedding was found in about 50% of the mice. Oocysts from the feces of naturally infected mice were infective for calves and mice. Calves began shedding oocysts at 7 days and shed oocysts for about 10 days. Nonfatal, clinical cryptosporidiosis developed in 7 infected calves. The mice began shedding oocysts at 6 days and shed oocysts for 12 days. Fatalities or clinical infection did not develop in 5 infected mice. The results indicated that Cryptosporidium-infected wild mice may be a source of cryptosporidiosis in susceptible calves.     

Organic matrix composition and ultrastructure of eggshell: a comparative study.

1. The avian eggshell is a biomineralised composite ceramic consisting of calcium carbonate embedded in an organic matrix. Matrix components are supposed to be involved in the control of mineralisation, crystallographic texture and biomechanical properties of eggshell. 2. The structure and eggshell matrix composition of various domesticated bird species were compared to gain insight into the universality of the eggshell mineralisation process. 3. The SDS-PAGE profiles of soluble eggshell matrix were specific within groups of birds (a: laying hen, breeder hen, quail, pheasant and possibly turkey; b: guinea fowl; c: duck and goose) but some of the protein bands were common to all groups. 4. Analogies between species were confirmed by Western blotting using hen protein antibodies. Ovocleidin-17 (OC-17) and ovalbumin were revealed in all species (except quail for OC-17). Lysozyme was present only in hen eggshell. Another egg white protein: ovotransferrin showed a positive signal in hens, turkey and quail. Osteopontin was observed in laying and breeder hens and quail. 5. Different proteoglycans were localised to discrete regions within the eggshell. Dermatan sulphate was observed within the matrix of the calcified shell of all species except quail which contained chondroitin-6-sulfate. Keratan sulphate was observed in mammillary bodies of breeder and laying hen, quail, pheasant and turkey while chondroitin sulphate was also present in guinea fowl and duck. 6. The general structural organisation of the different avian eggshells was similar but specific differences were observed in the ultrastructure of the mammillary layer. Species of the same taxonomic family could be grouped according to their structural analogies: breeder hen, turkey and pheasant resembled that of the domestic fowl. Guinea fowl was unique. Goose and duck were quite similar with large and confluent mammillary bodies. 7. Some matrix components are therefore common to eggshells of various species but more information is needed to relate differences in matrix composition between taxonomic groups with differences in ultrastructure.     

Pathogenesis of chicken-passaged Newcastle disease viruses isolated from chickens and wild and exotic birds

The pathogenesis of six Newcastle disease virus (NDV) isolates recovered from chickens (Ckn-LBM and Ckn-Australia) and wild (Anhinga) and exotic (YN parrot, pheasant, and dove) birds was examined after the isolates had been passaged four times in domestic chickens. Groups of 10 4-wk-old specific-pathogen-free white leghorn chickens were inoculated intraconjunctivally with each one of the isolates. The infected birds were observed for clinical disease and were euthanatized and sampled at selected times from 12 hr to 14 days postinoculation or at death. Tissues were examined by histopathology, by immunohistochemistry (IHC) to detect viral nucleoprotein (IHC/NP), and by in situ hybridization to detect viral mRNA and were double labeled for apoptosis (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling ([TUNEL] or IHC/caspase-3) and viral nucleoprorein (IHC/NP). Birds infected with the three low virulence viruses (Ckn-LBM, YN parrot, and Ckn-Australia) did not develop clinical disease. Microscopic lesions were observed only at the inoculation site and in organs of the respiratory system. The detection of viral nucleoprotein (N) was restricted to the inoculation site. The pheasant and dove isolates were highly virulent for chickens with marked tropism for lymphoid tissues, confirmed by the presence of large numbers of cells positive for viral N protein and viral mRNA. Viral N protein was detected early in the cytoplasm of cells in the center of the splenic ellipsoids. The apoptosis assays (TUNEL and IHC/caspase-3) showed increased apoptosis in the splenic ellipsoids as well. Apparently, apoptosis is an important mechanism in lymphoid depletion during NDV infection.     

Molecular detection and genotyping of microsporidia species in chickens in Turkey

Microsporidia are obligate intracellular pathogens that infect various hosts including invertebrates and vertebrates. Despite the importance, knowledge on the prevalence and molecular characteristics of microsporidia in chickens is limited, and no data are available for Turkey. A total of 300 fecal samples from chickens in the Central Anatolia Region of Turkey were analyzed by using a nested polymerase chain reaction assay targeting the rRNA internal transcribed spacer (ITS) region for the common microsporidia species. Corresponding PCR amplicons from the positive samples were sequenced for genotyping. Enterocytozoon bieneusi was identified in 22 (7.3 %) samples, whereas Encephalitozoon spp. was not detected. The prevalence of E. bieneusi was 63.6 % in Kayseri and 36.4 % in Nevsehir provinces, and 8.8 % in soft fecal samples and 9.7 % in diarrhoeic samples. No infections were found in Kirsehir Province. Significant differences were found for the distribution of E. bieneusi among provinces and fecal conditions. Infections were found only in free-range chickens. As a result of ITS region sequencing, two genotypes were characterized. The novel genotype ERUNT1 (n = 21), belonging to zoonotic group 1, was the most common genotype throughout the study area. The other known genotype, ERUSS1 (n = 1), had a restricted distribution and was previously detected in cattle and sheep in the same region. Our study provides the first data on microsporidia species from chickens in Turkey. None of these genotypes have been reported in humans; thus, the risk potential for public health is limited but needs further investigation.     

Activity of decoquinate against Cryptosporidium parvum in cell cultures and neonatal mice

Cryptosporidium parvum is an apicomplexan parasite that is an important cause of diarrhea in neonatal calves and humans. No treatment is currently available for neonatal calves. We have recently learned from colleagues in the pharmaceutical industry that dairy practitioners are sometimes using decoquinate for the treatment of neonatal bovine cryptosporidiosis. Therefore, the present study was undertaken to determine whether the clinical observations in calves can be substantiated by laboratory investigation. Oocysts of the KSU-1 isolate of C. parvum were used to infect human ileocecal epithelial cells in vitro to measure the efficacy of treatment using an ELISA based assay. No activity was observed at 10 or 50microM decoquinate, but at 100microM an 8% inhibition of development was seen. Oocysts of the AUCp-1 isolate of C. parvum were then used to infect suckling mice. The numbers of oocysts observed in suckling mice treated with 2.5 or 5.0mg/kg decoquinate were not significantly different from untreated control suckling mice (p0.05). The results of our study suggest that decoquinate should have little efficacy for treatment of neonatal bovine cryptosporidiosis if administered once per day and that any clinical improvement observed in treated calves may be due to factors unrelated to decoquinate's effect on C. parvum.     

An Alcaligenes faecalis isolate from turkeys: pathogenicity in selected avian and mammalian species

An Alcaligenes faecalis isolate of known pathogenicity for turkeys was examined for adherence and cytotoxicity in tracheal organ cultures of turkeys, chickens, Japanese quail, guinea pigs, hamsters, and mice, and for colonization and pathogenicity in these 6 species. Adherence and colonization were detected by fluorescent antibody staining. Infected and noninfected tracheal rings were examined by phase-contrast microscopy for cytotoxicity (ciliostasis, blebing of the cell membrane, and sloughing of the ciliated epithelium). Alcaligenes faecalis adhered to the tracheal rings of all species examined. Cytotoxicity was apparent in the tracheal rings of turkeys, quail, and chickens. Cytotoxicity was not detected in tracheal rings from the mammalian species. Alcaligenes faecalis colonization of turbinates and tracheas of intact turkeys and quail was detected. Clinical signs of alcaligenes rhinotracheitis were observed and histopathologic characteristics of the disease were detected. Chickens, guinea pigs, hamsters, and mice were refractory to infection with this isolate of A faecalis.     

Microsomal and cytosolic biotransformation of aflatoxin B1 in four poultry species

1. This research evaluated differences in hepatic in vitro metabolism of aflatoxin B1 (AFB1) on selected avian species. 2. Microsomal and cytosolic liver fractions were obtained from chickens, ducks, quails and turkeys; eight males and eight females of each. 3. All microsomes studied produced AFB1-8,9-exo-epoxide (AFBO), a metabolite regarded as the active product of AFB1. Turkey microsomes produced 1.8 and 3.5 times more AFBO than quails and chickens microsomes, respectively. 4. Males from evaluated birds produced more AFBO than females, but statistically-significant differences between genders were observed only in ducks and turkeys. 5. The cytosolic fraction from all four species produced aflatoxicol (AFL). Turkey and duck hepatic cytosol produced more AFL than from quail and chickens. 6. It is known that turkeys are very sensitive to AFB1, quails are intermediate and chickens are particularly resistant; the differences in AFBO production shown in our study may help to explain the difference in vivo responses among turkeys, quail and chickens. 7. Moreover, AFL may be related to AFB1 toxicity; it was produced in larger amounts by hepatic cytosol from the more susceptible species. 8. Because AFBO production by microsomes in ducks was relatively low, it is possible that other toxicity mechanisms are involved in this highly susceptible species.     

不同来源传染性支气管炎病毒诱导SPF鸡发病的免疫机制研究

试验旨在探讨不同来源的传染性支气管炎病毒(Infectious bronchitis virus,IBV)诱导SPF鸡发病的免疫机制。选用140只1日龄SPF白来航鸡,随机分为4组,3组攻毒组通过滴鼻点眼途径分别接种鸡源IBV强毒株、鸡源IBV弱毒株和野鸡源IBV毒株3个毒株,对照组以同种方式接种等量灭菌的磷酸盐缓冲液。在感染后12 h、36 h、72 h、7 d和14 d,每组随机选取5只进行剖检,并分别采集法氏囊、肾脏和气管组织,剩余鸡用于观察临床症状、发病及死亡情况。应用实时荧光定量PCR检测攻毒后不同时间点采集的各组织中IBV的病毒载量、Toll样受体(Toll-like receptors,TLRs)及部分细胞因子(白细胞介素(interleukin,IL)和干扰素(interferon,IFN))表达量的变化。结果显示,感染不同来源IBV毒株之后仅鸡源IBV强毒株感染组SPF鸡出现抑郁、翅膀下垂、甩头等典型的临床症状,且在感染后5~10 d共有7只死亡,死亡率为20%。病理剖检发现,感染鸡源IBV强毒株的鸡肾脏肿大、尿酸盐沉积和有花斑样病变,而感染野鸡源IBV毒株、鸡源IBV弱毒株和对照组的鸡无明显的眼观病变。实时荧光定量PCR结果显示,在鸡源IBV强毒株组的法氏囊、肾脏和气管3个组织中均检测到病毒。对照组和野鸡源IBV毒株组中均未检测到病毒,鸡源IBV弱毒株组只在部分组织中检测到病毒。在感染后72 h,鸡源IBV强毒株组与其他各组相比,TLR1、TLR2、TLR3、TLR5、TLR7和TLR15基因在法氏囊中的表达量均显著升高(P<0.05),IL-6和IFN-β参与更强烈的抗病毒免疫反应;在感染后7 d,鸡源IBV弱毒株组与其他各组相比,肾脏中TLR2、TLR3、TLR15、TLR21、IL-6和IL-18基因表达量均显著升高(P<0.05)。野鸡源IBV感染后36 h法氏囊组织中IFN-γ基因表达量显著上调(P<0.05)。综上所述,3个IBV毒株中仅鸡源IBV强毒感染引起SPF鸡典型临床发病症状与可视组织病变,且可提高SPF鸡组织中免疫相关因子的基因表达量。本研究结果揭示,不同来源的IBV对SPF鸡的不同致病性与其感染诱导的免疫反应不同有关。     

Genetic characterization and susceptibility on poultry and mammal of H7N6 subtype avian influenza virus isolated in Japan in 2009

From February to March 2009, six strains of H7N6 subtype avian influenza virus were isolated from quails in three farms in Aichi prefecture in Japan. The isolates were shown to be low pathogenic for chicken by the examination performed using the "Manual of Standards for Diagnostic Tests and Vaccines" by World organisation for Animal Health (OIE). The deduced amino acid sequence at the cleavage site was PE (I/Q/L) PKRR (nucleotide sequences were cct gaa (a/c) (t/a) a cc (a/g) aaa aga aga), suggesting persistence in domestic poultry for some time. The direct putative ancestor strain could not be elucidated by phylogenetic analysis of all genome segments of the quail isolates. Diverged date from a putative common ancestor in a non-rooted phylogenetic tree among quail viruses was estimated between March 2002 and July 2004. Three putative N-linked glycosylation sites resided in the vicinity of the receptor binding pocket of HA1 region. They are considered to decrease the reactivity of neutralizing antibody against the virus. Experiments for the infectivity and pathogenicity of a quail strain to poultry indicated that the quail isolate had higher infectivity to quails than chickens and ducks. Direct and dust-borne and/or droplet-borne transmissions among quail were proven in quails with and without direct contact with experimentally infected quails. The virus is seldom transmitted among chickens either directly or indirectly, and indirect transmission from infected quails to chickens was not observed. The pathogenicity of the quail strain for mammalian, pig and mouse was low, although it could replicate in those animals.     

鹌鹑源火鸡隐孢子虫在小白鼠和雏鸡体内内生发育阶段的超微结构比较

用鹌鹑源火鸡隐孢子虫（Cryptos poridium meleagridis）卵囊分别感染昆明系小白鼠和固始雏鸡，用透射电镜和扫描电镜观察比较了C．meleagridis在两种试验动物体内的内生发育虫体超微结构和致病性的差异。利用扫描电镜观察发现，鹌鹑源火鸡隐孢子虫（C.meleagridis）在小白鼠和雏鸡体内的寄生部位有较大差异，在小白鼠体内寄生于十二指肠，但在雏鸡体内主要寄生于回肠；C．meleagridis深嵌于小白鼠肠微绒毛丛内，微绒毛较为完整；但在雏鸡回肠，C．meleagridis似黏附在肠黏膜表面，微绒毛脱落明显，对雏鸡致病性明显比对小白鼠的致病性强。利用透射电镜在两种试验动物的样品中均观察到不同发育阶段的滋养体、裂殖体和大配子体以及正在孢子化的卵囊。滋养体和裂殖体在发育过程中可明显见到粗面内质网结构，裂殖生殖中期阶段粗面内质网尤其发达；小白鼠体内的C．meleagridis虫体与肠黏膜接触处形成一凹陷，寄生部位较深，而在雏鸡体内无此现象。此外，利用透射和扫描电镜均观察到虫体寄生部位周围微绒毛密度高而且也比其它部位长。形成这些差异的原因有待于进一步探讨。     

Mycobacterial infection in goats: Diagnosis and pathogenicity of the organism

Counterimmunoelectrophoresis of serum samples and intradermal tuberculin testing were compared with cultural results for the diagnosis of mycobacterial infection in a goat herd. Only eight of 47 culture-positive animals were not identified by a combination of the other two methods.Typical isolates resembled Mycobacterium paratuberculosis in cultural characteristics and mycobactin dependence but serologically resembled Mycobacterium avium. One isolate was inoculated into guinea-pigs, mice, chickens and calves and, although the infection in guinea-pigs, mice and chickens resembled that of M. paratuberculosis, it did not cause Johne's-like disease in calves.     

Effects of bovine respiratory syncytial virus on airway function in neonatal calves

Respiratory syncytial virus (RSV) infection causes severe lower respiratory tract disease in infants and calves. Neonatal respiratory tract infection in children often produces persistent changes in lung function. The specific objective of this study was to determine whether neonatal calves have transient or persistent alterations in pulmonary function and airway reactivity following RSV infection. Six 2- to 3-day-old Holstein bull calves were inoculated with 10 ml of bovine respiratory syncytial virus (BRSV) inoculum (10(2.7) to 10(3.8) cell culture infective doses/ml) intranasally and 10 ml of BRSV inoculum (10(4.8) to 10(5.9) cell culture infective doses/ml) intratracheally for 4 consecutive days, and 5 other calves were sham-inoculated. Prior to inoculation (day 0) and on days 4, 14, and 30 after the last inoculation, body weight (kg), dynamic compliance (Cdyn), pulmonary resistance (RL), and 2 indices of airway reactivity (effective dose [ED] 65Cdyn and ED200RL) were measured. Control calves gained weight progressively throughout the study, whereas RSV-inoculated calves failed to gain weight for 14 days, but equaled control calf weight by 30 days after inoculation. The Cdyn of control calves increased significantly by 30 days, but did not in the RSV-infected calves. Pulmonary resistance was increased significantly at 4, 14, and 30 days, but was unaffected by sham inoculation. The ED65Cdyn and ED200RL indicated an age-dependent increase in reactivity to histamine and an increase in responsiveness in the infected group beginning at 14 days and persisting until the end of the study.(ABSTRACT TRUNCATED AT 250 WORDS)     

Isolation and molecular characterization of Toxoplasma gondii from chickens and ducks from Egypt

The prevalence of Toxoplasma gondii in free range chickens is a good indicator of the prevalence of T. gondii oocysts in the environment because chickens feed from the ground. In the present study, prevalence of T. gondii in 121 free range chickens (Gallus domesticus) and 19 ducks (Anas sp.) from a rural area surrounding Giza, Egypt was assessed. Blood, heart, and brain from each animal were examined for T. gondii infection. Antibodies to T. gondii, assayed with the modified agglutination test (MAT), were found in 49 (40.4%) chickens in titers of 1:5 in 11, 1:10 in four, 1:20 in four, 1:40 in eight, 1:80 in 10, and 1:160 or more in 12 chickens. Antibodies were found in three ducks each with a titer of 1:80. Hearts and brains of seropositive (MAT > or = 1:5) chickens and ducks were bioassayed in mice. Additionally, hearts and brains of seronegative (MAT<1:5) animals were bioassayed in T. gondii-free cats. T. gondii was isolated from 19 of 49 seropositive chickens (one with a titer of 1:5, two with a titer of 1:20, one with a titer of 1:40, five with a titer of 1:80, three with a titer of 1:160, and seven with a titer of > or = 1:360). One cat fed tissues pooled from 15 seronegative chickens shed T. gondii oocysts, while two cats fed tissues of 34 seronegative chickens did not shed oocysts. T. gondii was isolated from one of the seropositive ducks by bioassay in mice. The two cats fed tissues from 16 seronegative ducks did not shed oocysts. Genotyping of 20 chicken isolates of T. gondii using the SAG 2 locus indicated that 17 isolates were type III and three were type II. The duck isolate of T. gondii was type III. The mice inoculated with tissue stages of all 21 isolates of T. gondii from chickens and ducks remained asymptomatic, indicating that phenotypically they were not type I because type I strains are lethal for mice. Infections with mixed genotypes were not found.     

Immunization against bovine tropical theileriosis, using 60Co-irradiated infective particles of Theileria annulata (Dschunkowsky and Luhs 1904) derived from ticks.

Portions of ground supernate material from Theileria annulata-infected and prefed adults of the Hyalomma anatolicum anatolicum were irridiated by 60Co source at 0, 3, 5, 6, 7, or 9 krads. These portions were injected subcutaneously into different groups of cross-bred calves. The calves injected with 0-, 3-, or 5-krad irradiated tick supernate had severe reactions (rectal temperature 39.8 to 41.6 C, two- to fourfold enlargement of prescapular lymph gland, mean peak parasitemia 27.3% to 32.5% infected erythrocytes, decreased PCV 41.7% to 60.7%, and hemoglobin concentration 37.5% to 50.8%), and many died, whereas those injected with 6- or 7-krad irradiated tick supernate had minimal reactions (rectal temperature 39.2 to 39.8 C, slight enlargement of prescapular lymph gland, parasitemia less than 1%, decrease packed cell volume 15.1%, and hemoglobin concentration 20.1%), with no mortality. All surviving calves injected with nonirradiated (0-) or 3-, 5-, 6-, or 7-krad irradiated tick supernate developed comparable indirect fluorescent antibody titers and were resistant to challenge exposure with infective material from 30 ticks. The calves injected with 9-krad irradiated tick supernate showed no reactions and did not develop indirect fluorescent antibody titers; they were also susceptible to challenge exposure with infective tick material.     

Experimentally induced pneumonic pasteurellosis: dose-response relationships and protection against natural reinfection in calves

Calves were inoculated intranasally with 2 X 10(6.2) tissue culture infective doses of infectious bovine rhinotracheitis virus, followed in 7 days by intratracheal inoculations with 1 of 4 challenge doses of pathogenic Pasteurella haemolytica. Severity and duration of the ensuing clinical signs of respiratory tract disease were correlated with the challenge dose of bacteria. Calves given 1 X 10(6) colony-forming units (CFU) of bacteria did not develop reliable clinical evidence of disease, whereas those given 1 X 10(8) CFU or 1 X 10(10) CFU of bacteria developed clinical signs of pneumonic pasteurellosis within 12 to 24 hours of bacterial challenge. Severity of clinical signs was equal at the 10(8) and 10(10) doses of bacteria, but duration of clinical signs was greater in calves given the 10(10) dose. Calves given 1 X 10(12) CFU of bacteria developed relatively severe respiratory tract disease in excess of what was necessary for positive clinical detection. Positive correlations were found between the bacterial challenge dose and the height and duration of increased rectal temperature, amount and duration of increases in ocular and nasal discharges, and the subjective evaluation of depressed attitude and appetite. Correlations were not found between challenge dose and respiratory rate or character, or between challenge dose and complete blood cell count. Convalescent calves were resistant to naturally occurring pneumonic pasteurellosis, which caused severe disease in nontreated calves. Adverse effects of P haemolytica were not observed after the first 4 to 15 days after bacterial administration; however, the bacteria were isolated from nasal secretions of convalescent calves 89 to 116 days after bacterial inoculation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pathogenic Shiga toxin-producing Escherichia coli in the intestine of calves

The purpose of this study was to compare the pathological effects of Shiga toxin-producing Escherichia coli (STEC) that vary in their association with bovine and human disease. Shiga toxin-producing E. coli of serotypes associated with both dysentery in calves and hemolytic uremic syndrome (HUS) in humans (O5:H-, O26:H11, O111:H-, O113:H21) were compared with O157:H7 STEC, which are associated with HUS in humans but not with disease in calves. The STEC were administered orally to 80 day-old chicks and into ligated loops in the ileum and colon of four 2- to 6-day-old calves. Examination of the ceca of the chickens 10 d postchallenge showed no adherence or tissue abnormality for any isolate. The calves were euthanized 8 to 10 h postinoculation, and sections of the intestinal loops were examined by light microscopy, transmission and scanning electron microscopy, and immunohistochemistry. All strains showed consistent focal adherence associated with mild lesions in the colon. Attaching and effacing lesions were observed with the eae-positive strains. Ileal lesions were similar to the colonic ones but were sometimes severe, with marked polymorphonuclear leukocyte proliferation in the lamina propria. It is concluded that chickens were unsuitable for studying interaction of STEC with the intestine and that there was no difference in the interaction of the ligated calf intestine with STEC of serotypes associated with disease in calves compared with O157:H7 STEC.     

Genetic and biologic characteristics of Toxoplasma gondii isolates in free-range chickens from Colombia, South America

The prevalence of Toxoplasma gondii in free-ranging chickens is a good indicator of the prevalence of T. gondii oocysts in the soil because chickens feed from the ground. The prevalence of T. gondii in 77 free-range chickens (Gallus domesticus) from Colombia, South America was determined. Antibodies to T. gondii were assayed by the modified agglutination test (MAT), and found in 32 (44.4%) of 72 chickens with titers of 1:5 in 4, 1:10 in 3, 1:20 in 1, 1:40 in 1, 1:80 in 8, 1:160 in 8, 1:320 in 3, and 1:640 or higher in 4. Hearts and brains of 31 seropositive chickens were pooled and bioassayed in mice. Tissues from 32 (16+16) seronegative chickens were pooled and fed to two, T. gondii-free cats, and tissues from nine chickens without matching sera were fed to one T. gondii-free cat. Feces of cats were examined for oocysts. T. gondii oocysts were excreted by a cat that was fed tissues of 16 seronegative chickens. T. gondii was isolated by bioassay in mice from 23 chickens with MAT titers of 1:20 or higher. All infected mice from 16 of the 23 isolates died of toxoplasmosis. Overall, 82 (81.1%) of 101 mice that became infected after inoculation with chicken tissues died of toxoplasmosis. Genotyping of these 24 isolates using polymorphisms at the SAG2 locus indicated that seven T. gondii isolates were Type I, 17 were Type III, and none was Type II. Phenotypically, T. gondii isolates from chickens from Colombia were similar to isolates from Brazil but different from the isolates from North America; most isolates from chickens from Brazil and Colombia were lethal for mice whereas isolates from North America did not kill inoculated mice. Genetically, none of the T. gondii isolates from Colombia and Brazil was SAG2 Type II, whereas most isolates from chickens from North America were Type II. This is the first report of genetic characterization of T. gondii isolates from Colombia, South America.     

Evaluation of interspecific hybrids of the chicken, guinea fowl, and Japanese quail for innate resistance to coccidia

Experimental chicken/guinea fowl hybrids, guinea fowl, and chickens were orally inoculated with Eimeria acervulina or E. tenella, which are specific for chickens, or with E. grenieri, which is specific for guinea fowl. No intact oocysts were found in feces within 24 hr of inoculation, suggesting that excystation occurred in the normal and abnormal hosts. No oocysts were found in the feces of hybrids during a 9-day postinoculation period. The guinea fowl passed oocysts of guinea fowl coccidia (E. grenieri) but not those of chicken coccidia, and the chickens passed oocysts of chicken coccidia (E. acervulina and E. tenella) but not those of guinea fowl coccidia. Some asexual development (schizogony) occurred in hybrids inoculated with E. tenella, but sexual development (gametogony) did not. In contrast, quail/chicken hybrids became infected with oocysts of chicken coccidia (E. acervulina, E. tenella, and E. maxima) and quail coccidia (E. bateri) and passed a few oocysts during the normal patent period; control chickens and quails became heavily infected with oocysts of chicken and quail coccidia, respectively.