Zika and chikungunya virus infections in hematopoietic stem cell transplant recipients and oncohematological patients.

Aedes mosquitoes are well adapted in domestic environments and widespread in tropical regions. Since 2015, Brazil has been experiencing a triple epidemic of dengue (DENV), chikungunya (CHKV), and Zika (ZIKV) viruses. The last 2 viruses are likely following the path of DENV, which has been endemic in most parts of the country since the 1980s. Given this triple epidemic, we proposed a prospective and collaborative study to assess the prevalence, morbidity, and mortality of DENV, CHKV, and ZIKV infections in hematopoietic stem cell transplant (HSCT) recipients and oncohematological patients. A case definition strategy (fever and rash) was used to prompt diagnostic investigation of DENV, ZIKV, and CHKV, which was accomplished by real-time polymerase chain reaction with plasma and urine samples. Clinical follow-up was performed 7 and 30 days after symptom onset. We report here the first cases of ZIKV and CHKV infections diagnosed in this ongoing study. From February to May 2016, 9 of the 26 patients (34.6%) fulfilling case definition criteria were diagnosed with DENV (3 cases), ZIKV (4 cases), or CHKV (2 cases) infections. Prolonged viremia and viruria were observed in dengue and Zika fever cases, respectively. Thrombocytopenia was the most frequent complication. Delayed engraftment was noted in 1 patient who acquired ZIKV 25 days before HSCT. All patients survived without sequelae. With the geographic expansion of arboviruses, donor and recipient screening may become mandatory. Patients living in areas where these viruses are not endemic are also at risk, since these viruses can be transmitted by blood as well as organ or tissue transplantation.