Table 1.

Encephalitis-associated deaths by category and study period, United States, 1979–1998

^*Per cent of all encephalitis-associated deaths during given study period. More than one cause of death consistent with encephalitis was listed in 0·6% of the records for 1979–1988 and 0·5% of the records for 1989–1998. Consequently, the sum of deaths in each category exceeds the total, and the sum of percentages exceeds 100%.

^†Introduced in 1987.

^‡This per cent includes the period before the introduction of the code 043.1. During 1987–1988, the only 2 years during this study period for which 043.1 was available, HIV encephalitis/encephalitis accounted for 1·5% of 2601 encephalitis deaths.

^§‘Encephalitis due to unknown cause’ includes deaths coded as ‘unspecified encephalitis’ (323.9), ‘unspecified viral encephalitis’ (049.9), ‘encephalitis due to unspecified mosquito-borne virus’ (062.9), and ‘encephalitis due to unspecified tick-borne virus’ (063.9), with the exception of deaths also coded with 043.1.

^¶The codes 136.3, 279.1, 279.3, 279.9, which represent pneumocystosis and immunodeficiencies, are not specific for HIV infection but were used as a surrogate for it, and were included for 1979–1986 only. HIV-specific codes (042–044 and 795.8) were introduced in 1987.