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[Biology of a newly isolated agent of the Chlamydia group]
Abstract:
The results of identification of the agent ("Progress" strain) isolated from the organs of a calf sacrificed in the early stage of pneumonia are presented. The agent adapted to yolk sacs of chick embryos was pathogenic for white mice by the intracerebral route and for monkeys infected with aerosol. The infected animals developed specific complement-fixing antibody. The antigen of the agent reacted in the CFT with homologous immune sera and with sera against ornithosis and other members of the ornithosis-lymphogranuloma-trachoma (OLT) group. In cell cultures the agent multiplied well and produced cytoplasmic inclusion bodies characteristic of the OLT group members.
Insights
A novel pathogen, the "Progress" strain, was identified from calf pneumonia. This agent proved pathogenic in mice and monkeys, producing specific antibodies and characteristic inclusion bodies, linking it to the ornithosis-lymphogranuloma-trachoma group.
Area of Science:
- Veterinary Microbiology
- Infectious Diseases
- Cell Biology
Context:
- Pneumonia in calves can be caused by various infectious agents.
- Early identification and characterization of pathogens are crucial for disease control.
- The ornithosis-lymphogranuloma-trachoma (OLT) group comprises significant zoonotic and animal pathogens.
Purpose:
- To identify and characterize the etiological agent responsible for pneumonia in a calf.
- To determine the pathogenicity and host range of the isolated agent.
- To classify the agent within the broader context of Chlamydiales bacteria.
Summary:
- The
- Progress
- strain was isolated from a calf with early-stage pneumonia and adapted to chick embryo yolk sacs.
- The agent demonstrated pathogenicity in white mice (intracerebral inoculation) and monkeys (aerosol infection), inducing specific complement-fixing antibodies.
- Antigenic analysis using complement fixation tests (CFT) showed cross-reactivity with sera from ornithosis and other members of the ornithosis-lymphogranuloma-trachoma (OLT) group.
- In cell cultures, the agent replicated effectively, producing cytoplasmic inclusion bodies typical of OLT group organisms.
Impact:
- Establishes the identity of a potential causative agent of calf pneumonia.
- Provides evidence for the zoonotic potential and broader epidemiological relevance of the OLT group.
- Highlights the utility of animal models and cell culture for pathogen characterization.