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[Antigenic types of circulating rotavirus in children with acute diarrhea in Santiago de Chile]
M O'Ryan1, N Mamani, L F Avendaño
1Departamento de Microbiología, Facultad de Medicina, Universidad de Chile, Santiago de Chile.
Insights
Rotavirus VP7 type G1 was the most common strain in Santiago, Chile, from 1993-1994 and 1985-1987. Understanding circulating rotavirus types is crucial for developing effective vaccines and preventive strategies.
Area of Science:
- Virology
- Immunology
- Public Health
Background:
- Protective immunity against rotavirus infection targets outer capsid proteins VP7 and VP4.
- Characterizing circulating rotavirus strains is essential for vaccine development and public health strategies.
Purpose of the Study:
- To determine the VP7 and VP4 antigenic types of rotavirus circulating in Santiago, Chile.
- To analyze the temporal and geographical distribution of these rotavirus types.
Main Methods:
- Collected 1206 stool samples from children with diarrhea (1993-1994) and 256 rotavirus-positive samples (1985-1987).
- Utilized ELISA for rotavirus detection and VP7 typing (G1-G4).
- Employed PCR for VP4 typing (P1-P4) on selected samples.
Main Results:
- Identified 782 rotavirus-positive samples; 618 (79%) were VP7 typable.
- VP7 type G1 predominated (63%), followed by G2 (13%).
- G2 types showed a progressive decrease; G4 types were more prevalent in 1985-1987; G3 types were not detected. Preliminary VP4 analysis indicated P1 predominance, associated with G1.
Conclusions:
- VP7 type G1 is the predominant rotavirus strain in Santiago, Chile.
- Observed shifts in rotavirus type prevalence over time and between study periods.
- Findings support the need for rotavirus vaccines effective against prevalent strains, particularly G1.
Abstract:
Protective immunity against rotavirus infection is directed against antigenic epitopes on the outer capsid proteins VP7 and VP4. The aim of this study was to characterize the VP7 and VP4 antigenic types circulating in different hospital areas of Santiago, Chile, over different time periods. Between April 1993 and April 1994 a total of 1206 stool samples were obtained from children consulting for acute no bloody diarrhea in 5 hospitals representative of the 5 major health areas of Santiago. In addition, 256 rotavirus positive samples, obtained from children with acute diarrhea consulting in the north health area of Santiago between 1985-1987 were studied. All samples were processed for rotavirus by an ELISA and all rotavirus positive samples were VP7 typed (types G1-G4) by a monoclonal antibody based ELISA. 50 rotavirus positive samples were selected for VP4 typing by PCR (types P1-P4). A total of 782 rotavirus positive samples were obtained of which 618 (79%) were typable for one specific VP7 type. VP7 type G1 represented 63% of the rotavirus positive samples and predominated in all areas evaluated throughout the entire period of observation. VP7 type G2 represented 13% of rotavirus samples, following G1 in predominance. G2 types decreased progressively in all areas in both study periods. G4 types were detected mainly during 1985-1987, and G3 types have so far not been detected. Preliminary analysis of VP4 types suggests that P1 types are predominant and closely associated with VP7 G1 type. These results are relevant for the adoption of appropriate preventive strategies for rotavirus infection, specifically aimed to the development of effective vaccines.