Kinetics of the appearance of Marek's disease virus DNA and antigens in the feathers of chickens

A comparison was made of the temporal appearance of six isolates of serotype 1 Marek's disease virus (MDV) in the feathers of specific pathogen-free (SPF) infected birds using three assays: agar gel precipitation (AGP), enzyme-linked immunosorbent assay (ELISA) and dot-blot DNA hybridisation. Isolate GA-5 served to standardise the in vivo pathogenicity assay, while the remaining five were recent isolates from Israel. Each isolate was inoculated into susceptible 4-day-old birds housed with an equal number of uninoculated birds. All six caused high mortality (80 to 100%) in the inoculated birds and a wide range of mortality (15 to 80%) in the contact groups. The transmission of infection from the inoculated group to the contact group was demonstrated for all six isolates by AGP and ELISA and for four isolates by dot-blot hybridisation. The other two isolates either showed a concurrent rise in MDV-DNA levels (isolate B) or failed to produce detectable levels of DNA in the inoculated and contact infected groups (isolate Ab). This could be due to the nature of the hybridisation reaction between the probe and the homologous sequence in the genome of isolate Ab. Antigenic activity was detected 11 days post-injection by ELISA, 14 days by AGP in some of the inoculated groups. In the contact infected birds the ELISA and dot-blot assays detected virus about 14 days earlier than did AGP. The time interval between the first detection of virus in the inoculated as compared with the contact infected groups differed for each assay and each isolate, viz; 10 to 14 days by ELISA, 14 to 24 days by AGP and 11 to 18 days by DNA-hybridisation.

Cultivation of Ehrlichia canis in a continuous BALB/C mouse macrophage cell culture line

This report describes the successful adaptation of the Israeli isolate of Ehrlichia canis on a continuous mouse macrophage cell line (J774.A1). Successful infection of the J774.AI cells was first judged by the direct immunofluorescence antibody test using an anti-E. canis-IgG:FITC conjugate. A particular property of infected J774.A1 cells was the ability to reestablish after harvesting of the monolayer by scaping. Infected cells were used as antigen for immunofluorescence antibody tests (IFA), and the results compared well with those of DH82 cells. It was concluded that the J774.A1 continuous cell line could serve as an alternate propagation cell line for E. canis organisms.

Ehrlichiosis associated vasculitis

OBJECTIVE

To test the hypothesis that some cases of primary vasculitis are caused by ehrlichiosis.

DESIGN

A retrospective case study and serological analysis of stored sera.

SETTING

University hospital.

SUBJECTS

Fifty-five patients discharged with any type of vasculitis over a 6-year period.

MAIN OUTCOME MEASURES

Serology for human monocytic ehrlichiosis, and the human granulocytic ehrlichiosis agent, and polymerase chain reaction (PCR) analysis of biopsy specimens.

RESULTS

Three patients (5.5%) had titres of 1 : 128 or higher against E. chaffeensis; none was positive for the human granulocytic ehrlichiosis agent. Skin biopsies of these patients showed lesions compatible with polyarteritis nodosa, allergic purpura and unspecified vasculitis. PCR analysis of the biopsies was unrevealing.

CONCLUSIONS

Infection with human monocytic ehrlichiosis may underlie some forms of vasculitis. If confirmed, these findings may help identify patients with vasculitis who would benefit from antibiotic treatment.

Comparison of a clinic-based ELISA test kit with the immunofluorescence test for the assay of Ehrlichia canis antibodies in dogs

The "gold standard" for the detection of antibodies to Ehrlichia canis, the cause of canine monocytic ehrlichiosis (CME), is the indirect immunofluorescence antibody (IFA) test. The IFA test however is generally available only in selected laboratories and requires extensive equipment and trained personnel. A double-blind study was conducted to compare the ability of an in-clinic standardized enzyme-linked immunosorbent assay (ELISA) test kit to measure E. canis IgG antibodies in dogs compared with the standard IFA technique. A good correlation was found between the 2 techniques (r2 = 0.8793; P < 0.0001). Evidence for the sensitivity of the ELISA technique for the early detection of E. canis IgG antibodies was demonstrated by comparing the appearance of E. canis antibody titers by the IFA and ELISA techniques after artificial infection of 2 sets of dogs. In both experimental infections, both tests were equally sensitive for the early detection of IgG antibodies against E. canis, and the results correlated well with the appearance of fever and clinical signs. Proposed application of the in-clinic ELISA test is to aid in the diagnosis of CME.

Antibodies reactive with Ehrlichia canis, Ehrlichia phagocytophila genogroup antigens and the spotted fever group rickettsial antigens, in free-ranging jackals (Canis aureus syriacus) from Israel

A seroepidemiological survey was conducted to investigate the prevalence of antibodies reactive with the Ehrlichia canis and Ehrlichia phagocytophila genogroup antigens, and the spotted fever group (SFG) rickettsiae antigens in jackals in Israel (Canis aureus syriacus), to assess the possible role of the jackal in the epidemiology of these diseases. Fifty-three serum samples from jackals were assayed by the indirect immunofluorescence antibody test. Antibodies to E. canis were detected in 35.8% serum samples while 26.4% of the samples tested were positive to Ehrlichia chaffeensis. Twenty-six percent of the jackals tested were seropositive to E. phagocytophila, of which 5.7% were seropositive to E. phagocytophila alone without any seroreactivity to either E. canis or E. chaffeensis. Fifty-five percent of the jackals were seropositive to the SFG-rickettsiae antigens. The results suggest a high exposure rate of jackals in Israel to E. canis. Positive reactivity to E. chaffeensis was considered to be due to antigenic cross-reactions with E. canis. The study demonstrated for the first time the presence of E. phagocytophila antibodies in free-range jackals. The high incidence of antibodies to the SFG-rickettsiae and their relatively high antibody titers was suggestive of either recent or persistent infection. The possibility that jackals may play a role in the transmission of E. canis, E. phagocytophila and the SFG-rickettsiae for human and canine infections is discussed.

Serologic evidence of human monocytic and granulocytic ehrlichiosis in Israel

We conducted a retrospective serosurvey of 1,000 persons in Israel who had fever of undetermined cause to look for Ehrlichia chaffeensis antibodies. Four of five cases with antibodies reactive to E. chaffeensis were diagnosed in the summer, when ticks are more active. All patients had influenzalike symptoms with high fever. None of the cases was fatal. Three serum samples were also seroreactive for antibodies to E. canis, and one was also reactive to the human granulocytic ehrlichiosis (HGE) agent. The titer to the HGE agent in this patient was higher than the serum titer to E. chaffeensis, and the Western blot analysis also indicated that the HGE agent was the primary cause of infection. We present the first serologic evidence that the agents of human monocytic ehrlichiosis (HME) and HGE are present in Israel. Therefore, human ehrlichiosis should be included in the differential diagnoses for persons in Israel who have been exposed to ticks and have influenzalike symptoms.

Kinetics of serologic cross-reactions between Ehrlichia canis and the Ehrlichia phagocytophila genogroups in experimental E. canis infection in dogs

The serological cross-reactions between the Ehrlichia canis and Ehrlichia phagocytophila genogroups, and the kinetics of development of antibodies in dogs to the E. phagocytophila group after artificial infection with the Israeli strain of E. canis was investigated. Results of this study indicate that the development of antibodies to the E. phagocytophila genogroup in dogs after infection with E. canis is a time dependent event probably conditional on the continued propagation of the rickettsia in the host. After spontaneous clinical recovery, and at the beginning of the subclinical phase, no antibodies to E. phagocytophila were yet detectable. The first evidence of IgG antibodies to E. phagocytophila were found in two of the six dogs, 55 days after artificial infection with E. canis, while another two dogs became seropositive to E. phagocytophila 22 days later. All surviving dogs were seropositive to E. phagocytophila by 150 days PI. It is suggested that the appearance of E. phagocytophila antibodies following treatment of acute E. canis infection may be used to judge treatment failure and/or persistence of infection.

Use of enzyme-linked immunosorbent assay techniques with cross-reacting human sera in diagnosis of murine typhus and spotted fever

Enzyme-linked immunosorbent assay (ELISA) techniques for the determination of immunoglobulin G to rickettsial lipopolysaccharides were developed. These techniques provide a simple and convenient way to serodiagnose Mediterranean spotted fever and murine typhus with a single serum dilution. The results of the ELISAs correlated with the indirect immunofluorescence assay titers of cross-reacting sera.

Pluralistic criteria for psychotherapy: an alternative to sectarianism, anarchy, and utopian integration

A pluralist revolution has taken place in psychotherapy, discarding the assumptions that only one theory can be true and that there exists only one method for finding it. Rejecting the anarchistic attitude of "anything goes" as professionally nihilistic, we propose that in the present pluralistic era it is necessary to recognize a multiplicity of perspectives for determining the rightness of therapeutic constructs. A construct or intervention is right to the extent that it fits demands for coherence and pragmatic value from a variety of perspectives, such as the patient's, the clinical community's, the academic community's, and the general public's. Within the clinical and academic communities, the greater the variety of acceptance (by different schools, theories, and methodologies), the greater the construct's cumulative rightness. The difference between this variety rule and a majority one is made explicit. Coherence and pragmatic value are widely accepted criteria and they define the universe of rational discourse in psychotherapy. Adding to these the requirement of multiple acceptability is the necessary step for creating rational dialogue in the new pluralistic world.

An improved ELISA method, using a streptavidin-biotin complex, for detecting Marek's disease virus antigens in feather-tips of infected chickens

To improve sensitivity in the detection of Marek's disease virus (MDV) antigens in extracts of feather tips from infected chickens, we added a preformed streptavidin-biotin complex to the standard enzyme-linked immunosorbent assay (ELISA). Rabbit anti-chicken IgG-alkaline phosphatase that is used in the standard ELISA as the conjugate was replaced by a biotinylated rabbit anti-chicken IgG plus the streptavidin-biotin peroxidase complex (ABC) system. The ABC-ELISA system was correlated to the standard ELISA. There was increased sensitivity in the detection of MDV antigens present at low concentrations, while at the higher concentrations detection was similar to that in the standard ELISA. Both ELISA systems had the same increased sensitivity when compared with that of the agar gel precipitation (AGP) test.