Clinical and epidemiological characteristics of subacute sclerosing panencephalitis in Bulgaria during the past 25 years (1978-2002).

The aims of the present study are to establish the subacute sclerosing panencephalitis (SSPE) incidence in Bulgaria for the 25-year period 1978-2002; to analyze the SSPE incidence prior to, and in the period of, routine measles immunization; and, to analyze the clinical characteristics of SSPE. SSPE was diagnosed in a total of 40 children; 28 of were diagnosed between 1978 and 1984, and 12 between 1995 and 2002. Thirty-eight cases (95%) were non-immunized and have had an early measles infection (mean age 16 months). The SSPE onset occurred primarily between 8 and 11 years of age (52.5%) with a mean latent period of about 7 years after the measles infection. After the 10-year disease-free period (1985-1994), the SSPE incidence increased between 1995 and 2002 because of the 1991-1992 measles epidemic. During the period 1995-2002 children with earlier measles infection and earlier SSPE onset predominated, compared to the period 1978-1984. The initial clinical manifestations included intellectual deterioration in 35%, extrapyramidal hyperkinesias in 29%, epileptic seizures in 15%, hemiparesis in 10%, and visual disturbances in 10% of the cases. Nine children (22.5%) demonstrated an atypical onset. A rapidly progressive course was observed in 4 children (10%) and a chronic progressive course with pseudoremissions over 2 years-in 8 cases (20%). Our analysis of the SSPE incidence in Bulgaria for the 25-year period (1978-2002) supports the importance of early measles infection as a crucial risk factor for this persistent neuroinfection. Moreover, it confirms the role of routine measles immunization in SSPE prevention.

Subacute sclerosing panencephalitis in Bulgaria (1978-2002).

The epidemiology of subacute sclerosing panencephalitis (SSPE) has changed substantially since the introduction of measles vaccine. We studied the incidence of SSPE in Bulgaria based on cases admitted to the Child Neurology Clinic, University Hospital of Neurology and Psychiatry, Sofia, for a 25-year period (1978-2002). The SSPE incidence prior to and during the period of routine measles immunization was analyzed. SSPE was diagnosed in 40 children (29 males and 11 females, mean age 8.5 years), 28 from 1978 to 1984 (average 4 patients/year), and 12 from 1995 to 2002 (average 1.7 patients/year). Thirty-eight cases (95%) were non-immunized and had early measles infection. Age at onset of SSPE ranged from 8 to 11 years (52.5%) with a mean latent period of 7 years following measles infection. The increase in SSPE incidence (1995-2002) following a 10-year disease-free period (1985-1994) appears to be related to early measles infection (mean age 11 months) during the measles epidemic of 1991-1992. During the period 1995-2002, children had earlier measles infection (average 11 months) and earlier onset of SSPE (mean age 8.4 years) than in the period 1978-1984 (mean age at measles infection 18 months, and of SSPE onset 11.2 years). The SSPE incidence in Bulgaria during the 25-year period from 1978 to 2002 confirms the importance of early measles infection as a risk factor for SSPE, and the role of routine measles immunization in SSPE prevention.