[Laboratory surveillance of measles. Chile, 1992-1995].

BACKGROUND

The first massive national measles vaccination campaign in Chile was done in 1992. Since then a laboratory surveillance of the disease has been undertaken at the Instituto de Salud Pública.

AIM

To report the results of laboratory surveillance of measles between 1992 and 1995.

MATERIAL AND METHODS

Paired serum samples from suspected cases of measles were received at the Institute. Measles specific IgG was determined with indirect immunofluorescence methods. IgG and IgM immunoenzymatic methods were used as complementary techniques, and rubella infections were ruled out by hemmaglutination inhibition tests.

RESULTS

Sera from 1087 presumptive cases (489 in 1992, 196 in 1993, 180 in 1994 and 222 in 1995) were analyzed. Only two cases of wild imported measles were confirmed, one in Arica in 1992 and the other in Santiago in 1993. Five additional post vaccine cases were detected. Eighty eight percent of samples in 1992 and 75% in 1994 were seropositive. A high percentage of cases were confirmed as rubella (55% in 1992 and 19% in 1994).

CONCLUSIONS

Absence of wild measles virus circulation in Chile from 1992 to 1995 emphasizes the importance of laboratory surveillance of the disease.