Antigenic analysis of Giardia duodenalis strains isolated in Alberta

Giardia duodenalis is a common intestinal parasite in most parts of the world. In Canada it is associated with both endemic and epidemic infections that are often transmitted by the waterborne route. Although G. duodenalis strains have been isolated from several animals, the role of other mammals in human infection is unclear. We have isolated and cultured G. duodenalis trophozoites from domestic and wild animals in Alberta and compared them with a human isolate by protein gel electrophoresis and immunoblot analysis. All strains examined share a similar polypeptide profile and important protein antigens. Prominent antigens of 62, 52, 38, and 31 kilodaltons are conserved. The 52- and 31-kilodalton proteins are the major surface-exposed trophozoite components. The high degree of antigenic sharing among strains from different hosts suggests that there may be a wide range of potential reservoirs for G. duodenalis infections.     

Preliminary X-ray crystallographic analysis of canine parvovirus crystals

The first diffraction pattern of a crystalline single-stranded DNA virus has been obtained. Canine parvovirus was crystallized in a monoclinic P21 unit cell with a = 264.4 A, b = 350.3 A, c = 267.8 A and beta = 90.86 degrees (1 A = 0.1 nm). The diffraction pattern extends to at least 2.8 A resolution. Packing of the particles suggests that they have a diameter around 257 A, in excellent agreement with the reported molecular weight of 5.5 x 10(6).     

Characterization of a canine parvovirus strain isolated from an adult dog

A CPV-2b strain was detected from an adult vaccinated dog, affected with severe gastroenteritis. The faeces of the dog were positive to canine parvovirus by a hemagglutination assay and gave a CPV-2b-like pattern by a hemagglutination inhibition test using monoclonal antibodies. In vitro-cultivation of the virus was difficult and after a few passages on canine and feline cells, the presence of the virus was detectable only by an immunofluorescence assay on the feline cells, since hemagglutinating activity had disappeared. Characterization of the virus, by an indirect immunofluorescence assay with monoclonal antibodies, confirmed the antigenic CPV-2b-like pattern of the nonhemagglutinating virus.     

Comparative survey of canine parvovirus,canine distemper virus and canine enteric coronavirus infection in free-ranging wolves of central Italy and south-eastern France

Diseases likely affect large carnivore demography and can hinder conservation efforts. We considered three highly contagious viruses that infect a wide range of domestic and wild mammals: canine parvovirus type 2 (CPV-2), canine distemper virus (CDV) and canine enteric coronaviruses (CECoV). Infection by either one of these viruses can affect populations through increased mortality and/or decreased general health. We investigated infection in the wolf populations of Abruzzo, Lazio e Molise National Park (PNALM), Italy, and of Mercantour National Park (PNM), France. Faecal samples were collected during one winter, from October to March, from four packs in PNALM (n?=?79) and from four packs in PNM (n?=?66). We screened samples for specific sequences of viral nucleic acids. To our knowledge, our study is the first documented report of CECoV infection in wolves outside Alaska, and of the large-scale occurrence of CPV-2 in European wolf populations. The results suggest that CPV-2 is enzootic in the population of PNALM, but not in PNM and that CECoV is episodic in both areas. We did not detect CDV. Our findings suggest that density and spatial distribution of susceptible hosts, in particular free-ranging dogs, can be important factors influencing infections in wolves. This comparative study is an important step in evaluating the nature of possible disease threats in the studied wolf populations. Recent emergence of new viral strains in Europe additionally strengthens the need for proactive monitoring of wolves and other susceptible sympatric species for viral threats and other impairing infections.     

猪源大肠杆菌F18菌毛的体外表达和抗原特性

摘要:【目的】揭示从仔猪腹泻和/或水肿病猪体内分离到的fedA + 大肠杆菌所携带的毒力因子、F18菌毛在体外表达及其抗原变异情况。【方法】利用凝集试验测定O 血清型,PCR方法检测毒力基因,单克隆抗体分析F18菌毛抗原特性。【结果】在75个fedA + 分离株中,有62株测定出其O血清型,覆盖8种血清型,以O107和O139为主(74.2%) ;estI、estII、elt、stx-2e、astA、orfA、irp2、fyuA、ler和eaeA基因在这75个菌株中的检出率分别为64.0%、46.7%、28.0%、62.7%、26.7%、9.3%、9.3%、9.3%、1.3%和1.3%,其中仅拥有stx-2e基因的菌株有19株,同时拥有estI/estII/stx-2e基因的菌株有20株。单抗鉴定结果显示,在33株体外表达F18菌毛的菌株中,21株(63.6%)被鉴定为F18ac变体,2株(6.1%) 被鉴定为F18ab变体,其余10株(30.3%)仅跟F18“a”因子单抗反应,而不跟F18“b”、“c”因子单抗反应。间接ELISA显示,11株单抗至 少识别F18菌毛的6个表位,其中“a”因子至少有3个表位,“b”因子至少有2个表位,“c”因子至少有1个表位。【结论】在猪源菌株中,F18ab菌毛在体外表达率较低;F18ac菌毛在体外表达率较高,主要与肠毒素和O107血清型相关,同时我国存在F18菌毛的抗原变异。     

Equine and canine Anaplasma phagocytophilum strains isolated on the island of Sardinia (Italy) are phylogenetically related to pathogenic strains from the United States

The presence of Anaplasma phagocytophilum, a tick-transmitted zoonotic pathogen, was investigated in Sardinia using a molecular approach. Phylogenetic analysis revealed that Sardinian strains are genetically distinct from the two lineages previously described in Europe and are closely related to strains isolated in different areas of the United States.     

Genotyping of Legionella pneumophila serogroup 1 strains isolated in Northern Sicily, Italy

During a three-year period, from April 2002 to May 2005, one hundred-forty-seven samples, taken from technical systems of water distribution at point of use, were repeatedly collected at six different sites in Northern Sicily and assayed for the presence of Legionella pneumophila serogroup 1 and serogroups 2 to 14. At the first samplings, the water distribution systems of all the sites were heavily contaminated, and disinfection treatments by the superheat and flush method were therefore performed. Treatments were always successful against L. pneumophila sg.1, but only in a few cases against all other serogroups. Eighty-six strains of L. pneumophila sg. 1, isolated from 26 of these samples, were characterized by amplified fragment length polymorphism (AFLP) analysis and sequence-based typing (SBT) procedure. Perfectly overlapping results were obtained by both the procedures and four genotypes were identified, accounting for all the isolates. The easy transferability of the SBT data through a web-based database made it possible to identify the presence in Northern Sicily of the two SBT types most commonly circulating in Europe.     

Antigenic structure of the polysaccharide capsule of Streptococcus pneumoniae strains isolated in Leningrad 1978-1984

The serotyping of 826 S. pneumoniae strains, isolated in conditionally diagnostic concentrations from the bronchial contents of patients with acute and chronic inflammatory pulmonary diseases during 1978-1984 in Leningrad, was made. The study revealed the prevalence of serotypes and groups 6, 23, 9, 3, 19, 15 and the undulant character of fluctuations in their annual occurrence. The specific proportion of the prevailing serotypes of S. pneumoniae among the cultures isolated from patients with acute pneumonia and acute bronchitis (6 and 19) was found to differ from that among S. pneumoniae strains isolated from patients with chronic bronchitis; in the latter patients serotypes 3 and 9 occurred more frequently (P less than 0.01).     

Antigenic and molecular characterization of Vibrio ordalii strains isolated from Atlantic salmon Salmo salar in Chile

Biochemical, serological and molecular properties of a group of 14 Vibrio ordalii strains isolated from cultured Atlantic salmon Salmo salar in Chile in recent years were studied. The characteristics of isolates were compared with the type strain V. ordalii ATCC 33509T. The Chilean V. ordalii represented a biochemically homogenous group; however, some minor differences with the type strain were observed. The serological relationships among isolates, as well as the study of their antigenic determinant (LPS) revealed a strong reaction with antisera raised against Atlantic salmon strains and the antiserum raised against Listonella anguillarum serotype O2. However, LPS electrophoretic patterns were completely different from the V. ordalii type strain, regardless of the serum employed, suggesting the possibility that the Chilean strains constitute a new serological subgroup within this bacterial species. Genetic analyses by PFGE, RAPD, REP-PCR and ERIC-PCR demonstrated that all V. ordalii strains were genetically homogenous, displaying similar DNA patterns, regardless of the techniques used. Moreover, the analysis of DNA banding patterns generated by ERIC-PCR and REP-PCR also clearly separated the type strain from the Chilean strains. This is the first report of characterization of V. ordalii strains from the Southeastern Pacific area, the results of which should facilitate the development of vaccines for protecting cultured Atlantic salmon against vibriosis in this area.     

Recombinant vaccine for canine parvovirus in dogs.

VP2 is the major component of canine parvovirus (CPV) capsids. The VP2-coding gene was engineered to be expressed by a recombinant baculovirus under the control of the polyhedrin promoter. A transfer vector that contains the lacZ gene under the control of the p10 promoter was used in order to facilitate the selection of recombinants. The expressed VP2 was found to be structurally and immunologically indistinguishable from authentic VP2. The recombinant VP2 shows also the capability to self-assemble, forming viruslike particles similar in size and appearance to CPV virions. These viruslike particles have been used to immunize dogs in different doses and combinations of adjuvants, and the anti-CPV responses have been measured by enzyme-linked immunosorbent assay, monolayer protection assays, and an assay for the inhibition of hemagglutination. A dose of ca. 10 micrograms of VP2 was able to elicit a good protective response, higher than that obtained with a commercially available, inactivated vaccine. The results indicate that these viruslike particles can be used to protect dogs from CPV infection.     

Different strategies for molecular differentiation of Mycobacterium bovis strains isolated in Sardinia, Italy

Different genetic markers were used to analyze 22 Mycobacterium bovis strains isolated from cattle in Sardinia and one human isolate. IS6110 DNA fingerprinting differentiated the strains into six patterns, whereas with enterobacterial repetitive consensus sequence primers produced seven clusters. PCR ribotyping followed by digestion with HaeIII and PvuII produced five and seven patterns, respectively. PCR with the (GTG)5 oligonucleotide primer showed the best discriminatory power, generating eight clusters among the strains analyzed.     

Antigenic relationship of Geotrichum candidum strains

Summary Twelve cultures ofGeotrichum candidum have been examined by agglutination, agglutinin adsorption, passive cutaneous anaphylaxis and dermal sensitivity tests. Because of widespread cross reactivity between the strains in these tests, it was concluded that surface and internal sharing of antigens exists.Supported in part by the University of Missouri Research Council.     

Antigenic analysis of three strains of Mycoplasma arginini by two-dimensional immunoelectrophoresis.

The occurrence of species-specific and strain-specific antigens in three strains of Mycoplasma arginini (G-230, leonis and 23243) was studied by two-dimensional immunoelectrophoresis. Approximately 20 antigenic components could be detected in each strain. It was possible to analyze 6 to 7 major and distinct components from each strain by two techniques: "enhancement" where antigen to an additional strain is added to the first phase of the electrophoresis which increases the size of common peaks and "suppression" where antiserum to an additional strain is incorporated in the second phase whereby peak size of components to which both sera have antibody are decreased. A total of 10 distinct antigens were recognized. Electrophoretic mobilities relative to bovine albumin ranged from 0.2 to 1.08. Three components were common to all strains; two of these represented major amounts of material. Four components represented strain-specific components. Unique fast components were found both in strains 23243 and G-230. Three antigens were distributed into only two of the three strains. The electrophoretic mobilities of some common antigens were quite different between strains.     

Evaluation of lactogenic immunity to canine parvovirus in pups

Maternally-derived antibodies (MDA) transferred to pups through colostrum and milk are known as lactogenic immunity. In this report, we describe the kinetics of transfer of lactogenic immunity to canine parvovirus type 2 (CPV-2) from two bitches (A and B) to their offspring. At day 7 before parturition, bitches A and B had high serum antibody titers, which decreased rapidly within a few hours after parturition, in concomitance with the appearance of high HI titers in colostrum. Subsequently, the serum antibodies of the two dogs increased again, reaching approximately the initial titers. CPV-specific antibodies were observed in milk, with decreasing values, throughout the lactation period. The kinetics of MDA observed in the pups was consistent with the patterns of absorption and decline previously described.