Development and evaluation of co-agglutination test to detect rotavirus antigens in stools of patients with diarrhoea.

Rotavirus is the most common cause of acute diarrhoea in infants and children in both the developed and developing countries including Bangladesh. Information about rotavirus diarrhoea in Bangladesh is insufficient primarily due to the lack of diagnostic facilities due to the high cost of reagents and equipment and lack of skilled personnel. A simple, suitable and less costly technique of co-agglutination test using protein-A secreting staphylococci was developed and evaluated against a commercially available ELISA kit to detect rotavirus antigen in stools of patients with diarrhoea. Staphylococcus cowan strain 1 was grown and coated with rabbit antisera raised against RV5 and SA11 rotavirus strains. The antibody-coated staphylococci were agglutinated specifically by rotavirus present in faecal samples within one or two minutes. A total of 1332 stool specimens were tested by co-agglutination and ELISA, of which 210 (15.77%) were positive by ELISA and 276 (20.72%) by co-agglutination test. Compared to ELISA, sensitivity of co-agglutination test was 76.19%, specificity 89.66% and predictive values of a positive and a negative test were 57.97% and 95.26% respectively. The results indicate that the co-agglutination test is a simple and suitable technique for rapid screening of rotavirus infection which could be adopted in clinical practice.