Primary infection with the human immunodeficiency virus causes profoun
d immunosuppression with a decrease in lymphocyte numbers and function
. However, this immunosuppression is transient and most individuals re
gain normal immune function. Infection with opportunist pathogens duri
ng the period of immunosuppression is rare. We report a case of severe
prolonged cryptosporidiosis complicating primary HIV infection. This
has not previously been described. A review of other cases of opportun
ist infections in primary HIV infection suggests that various pathogen
s may take advantage of the transient immunosuppression. This has impo
rtant implications for the diagnosis and management of acute HIV infec
tion, and for the diagnostic criteria currently used for AIDS.