Prevalence of antibodies to human caliciviruses (HuCVs) in Kuwait established by ELISA using baculovirus-expressed capsid antigens representing two genogroups of HuCVs.

Baculovirus recombinant-expressed antigens of Norwalk viruses (rNV) and a Mexico strain (rMX) of the Snow Mountain serogroup of human caliciviruses (HuCVs) were used in enzyme immunoassays to study the antibody prevalence among the Kuwaiti population and foreign workers employed in Kuwait. The antibody titers in 16 different age groups which ranged from neonates to centenarians were investigated by testing eight different dilutions of each serum (1:200-1:25,600). The results indicate that NV infection is widespread in Kuwait and affects all age groups Ninety-eight percent of the 433 serum samples tested had antibodies to rNV. In the 50-79-year, old age group, the antibody levels to rNV were higher and significantly different from those in children 0-7 years old. In infants, the rNV antibodies did not diminish by 4 months of age and their titer steadily increased with age. When 414 of these sera samples were tested for antibodies to rMX, 96% positive serological responses were observed. Antibody titers to rMX were reduced in infants from 4 to 11 months; however, 95% of the samples were positive. These data indicate that children born in Kuwait are infected with Norwalk-like viruses at a very early age. Finally, antibodies to rNV and rMX were found in 98% of 151 and in 95% of 148 foreign workers, respectively.