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Characteristics of an adenovirus type 19 conjunctivitis isolate and evidence for a subgroup associated with epidemic
Abstract:
Although adneovirus type 19 (Ad19) was first described in 1955, this virus was not associated with disease until its isolation from outbreaks of conjunctivitis in 1973. A strain of Ad19 isolated from a case of conjunctivitis in Seattle in 1974 was compared with the reference strain (3911). Plaque number and size were enhanced by 30 mM MgCl2. Low pH and chloroform treatment had no effect on either strain's activity, but the two strains were sensitive to pH 8. Growth curves were characteristic of adenoviruses, but differences were seen in the amount of virus released. The ratios of particles to plaque-forming units (approximately 10,000:1) were similar for both. Both virus preparations contained high concentrations of group-specific complement-fixing antigen. Cross-reactions were seen by hemagglutination inhibition and immunoelectron microscopy between antisera to Ad8, Ad9, and Ad10 versus both strains of Ad19, but were not seen by neutralization. We would like to suggest, based on exclusive conjunctivitis association and cross-reactions, that the four cross-reacting serotypes, Ad8, Ad9, Ad10, and Ad19, represent a subgroup of adenoviruses specfically associated with conjunctivitis.
Insights
Adenovirus type 19 (Ad19), linked to conjunctivitis outbreaks, was compared to a reference strain. Similarities and differences in viral characteristics suggest Ad19 may form a subgroup with Ad8, Ad9, and Ad10, all associated with eye infections.
Area of Science:
- Virology
- Ophthalmology
- Infectious Diseases
Background:
- Adenovirus type 19 (Ad19) was first identified in 1955 but not linked to disease until 1973.
- Outbreaks of conjunctivitis have been associated with Ad19 since 1973.
Purpose of the Study:
- To compare a newly isolated strain of Ad19 from conjunctivitis with the reference strain (3911).
- To investigate the virological characteristics and antigenic relationships of Ad19.
Main Methods:
- Comparative analysis of Ad19 strains (Seattle 1974 and reference 3911).
- Assays included plaque formation (effect of MgCl2, pH, chloroform), growth curves, particle to PFU ratios, complement fixation, hemagglutination inhibition, immunoelectron microscopy, and neutralization.
- Antisera to Ad8, Ad9, and Ad10 were used to test for cross-reactivity.
Main Results:
- Plaque formation was enhanced by MgCl2; strains were sensitive to pH 8 but not low pH or chloroform.
- Growth curves were typical of adenoviruses, with variations in virus release.
- High concentrations of group-specific complement-fixing antigen were present.
- Cross-reactions were observed via hemagglutination inhibition and immunoelectron microscopy with Ad8, Ad9, and Ad10 antisera, but not neutralization.
Conclusions:
- Ad19 shares characteristics with other adenoviruses but shows distinct release patterns.
- The observed cross-reactions suggest Ad8, Ad9, Ad10, and Ad19 may constitute a distinct adenovirus subgroup associated with conjunctivitis.