BACKGROUND: Virus investigation, specially cytomegalovirus (CMV), in b
lood has increased such that the capacity of hospitalary laboratories
is threatened with collapse. The causal agents of viremia are analyzed
being correlated with the clinical symptoms and underlying disease to
establish the selection criteria of patients for virologic study. MET
HODS: Two thousand six hundred nineteen patients suspected of having v
iral infection, fundamentally by CMV were studied over 6 years by 4,39
4 blood samples. Of these patients 1,646 were immunosuppressed, 824 we
re considered immunocompetent and this data was unknown in 149 patient
s. The leukocytes were separated using standardized techniques being s
eeded in cell cultures (human embryon lung fibroblasts). RESULTS: Thre
e hundred forty-seven specimens corresponding to 242 patients were pos
itive with isolation of the following pathogens: 327 strains of CMV, 4
enterovirus, 2 adenovirus, 1 herpes simplex virus, 1 varicela-zoster,
another 5 unidentified cytopathic agents, 6 strains of toxoplasma and
1 Cryptococcus. With regard to the base disease, 302 positive samples
to CMV pertained to 204 immunosuppressed patients: 103 (13.6 % positi
ves among the cases studied) AIDS or AIDS-related complex, 54 (21.3 %)
kidney transplant patients, 31 (24.8 %) liver transplant patients, 2
(1.5 %) lung transplant patients, and 2 (1.5 %) bone marrow transplant
patients. A non CMV microorganism was isolated in 13 samples from 12
immunosuppressed patients. Only 24 (2.5 % of those studied) immunocomp
etent or with unknown immunity status had viremia by CMV, being detect
ed in 25 samples. Non CMV cytopathic agents were isolated in another 7
samples from 6 patients. CONCLUSIONS: Analysis of blood cultures allo
ws the isolation of cytomegalovirus and occasionally other unsuspected
agents such as toxoplasma. This investigation is indicated in immunos
uppressed patients but not in immunocompetent patients who present a f
ebrile syndrome with no clinical suspicion of cytomegalovirus infectio
n.