Zika virus epidemic in Brazil. I. Fatal disease in adults: Clinical and laboratorial aspects

Abstract

Background: Zika virus (ZIKV) was first detected in Brazil in May 2015 and the country experienced an explosive epidemic. However, recent studies indicate that the introduction of ZIKV occurred in late 2013. Cases of microcephaly and deaths associated with ZIKV infection were identified in Brazil in November, 2015.

Objectives: To determine the etiology of three fatal adult cases.

Study design: Here we report three fatal adult cases of ZIKV disease. ZIKV infection in these patients was confirmed by cells culture and/or real-time reverse transcriptase polymerase chain reaction (RT-qPCR) and by antigen detection using immunohistochemical assay. Samples of brain and other selected organs taken at autopsy from three patients were also analyzed by histopathological and immunohistological examination.

Results: The first patient, a 36-year-old man with lupus and receiving prednisone therapy, developed a fulminant ZIKV infection. At autopsy, RT-qPCR of blood and tissues was positive for ZIKV RNA, and the virus was cultured from an organ homogenate. The second patient, a previously healthy female, 16 years of age, presented classic symptoms of Zika fever, but later developed severe thrombocytopenia, anemia and hemorrhagic manifestations and died. A blood sample taken on the seventh day of her illness was positive RT-PCR for ZIKV RNA and research in the serum was positive for antinuclear factor fine speckled (1/640), suggesting Evans syndrome (hemolytic anemia an autoimmune disorder with immune thrombocytopenic purpura) secondary to ZIKV infection. The third patient was a 20-year-old woman hospitalized with fever, pneumonia and hemorrhages, who died on 13days after admission. Histopathological changes were observed in all viscera examined. ZIKV antigens were detected by immunohistochemistry in viscera specimens of patients 1 and 3. These three cases demonstrate other potential complications of ZIKV infection, in addition to microcephaly and Guillain-Barre syndrome (GBS), and they suggest that individuals with immune suppression and/or autoimmune disorders may be at higher risk of developing severe disease, if infected with ZIKV.

Keywords: Autoimmune disorders; Erythematous lupus; Evans syndrome; Histopathology; Immunohistochemistry; Zika virus.

Fig. 1

Histopathological aspects of Case 1. Fig. 1A–C – Brain showing neuronal necrosis especially in basal nuclei, edema, gliosis, neuronophagia and perivascular hemorrhage. Fig. 1D and E – Liver with cellular edema, lytic necrosis (circle), macro and micro steatosis (rectangles) and acidophilic bodies (arrows) associated with mononuclear inflammatory response. Fig. 1F – Spleen with congestion and hemorrhage. Fig. 1G – Heart with interstitial mononuclear cell infiltration, edema and fibrosis of undetermined infarct. Fig. 1H – Lung shows edema, congestion and hemorrhage (HE, Magnification: ×40).

Fig. 2

Immunohistochemistry of Case 1. Fig. 2A–C – Areas expressing ZIKV antigens in the brain, especially in the neuronal bodies with (arrows) and without (arrow heads) nucleus and proximal dendrites. Fig. 2D – ZIKV antigens observed in pulmonary alveoli (ellipses). Fig. 2E – ZIKV antigens observed in myocardial tissue (rectangles). Fig. 2F and G – ZIKV antigens observed in hepatocytes (rectangle). Fig. 2H and I – ZIKV antigens in epithelia of renal tubules (circles) (IHC SAAP, Magnification: ×40, except Fig C – IHC SAAP, Magnification: ×100).

Fig. 3

Histopathological aspects of Case 3. Fig. 3A – Lobar pneumonia: hemorrhage, fibrin leukocyte exudates and hyaline membrane (HE, Magnification: ×10). Fig. 3B – Kidney: glomerulus presenting cell hyperplasia and tubules with cell edema (arrows) (HE, Magnification: ×40). Fig. 3C – Liver with areas of necrosis, apoptosis, Councilman bodies (large arrows) and steatosis (thin arrows) (HE, Magnification: ×40). Fig. 3D – Liver with large area of necrosis, confluent and forming bridges (arrows) between the lobes (HE, Magnification: ×10).

Fig. 4

Immunohistochemistry of Case 3. Fig. 4A – Positive immunostaining for ZIKV antigens in alveolar lining cells (circle) (IHC SAAP, Magnification: ×40). Fig. 4B – Positive immunostaining for ZIKV antigens in renal tubule (circle) (IHC SAAP, Magnification: ×40). Fig. 4C – Positive immunostaining for ZIKV antigens in hepatocytes of necrotic margins and apopototic cells, Councilmann bodies (circles) (IHC SAAP, Magnification: ×40). Fig. 4D – Positive immunostaining for ZIKV antigens in hepatocytes (circle) characterized by acidophilic and granular appearance in the cytoplasm (IHC SAAP, Magnification: ×40).

Fig. 5

Phylogeny of the Env gene region ZIKV Case 1 (BeH818305, Accession Number: KU729218). ML bootstrap scores are shown next to nodes. The tree was estimated using PhyML. Sequence names include accession number, strain name, location of sampling and date of sampling. Isolates in this study: Strain BeH815744 – self-limited clinical infection in patient from João Pessoa, Paraíba State, Northeast Brazil; Strains BeH819966, BeH818995 BeH819015- self-limited clinical infection in patient from Belém, Pará State, North Brazil; Strain Z1106033 – self-limited clinical infection in patient from Paramaribo, Suriname; Strain SPH2015 (death) blood donor patient from Sumaré, São Paulo State, Southeast Brazil; Strain Haiti1225 – undifferentiated febrile illness in patient from Gressier/Leogane region of Haiti; Strain H/PF/KJ77679 case with fever, headache, myalgia, arthralgia, and rash in patient returning from French Polynesia; Strain ECMN/EU545988 – sample collected in April 2007 during an outbreak of rash, conjunctivitis, and arthralgia in state of Yap, Micronesia; P6740/HQ234499 – sample obtained from Aedes aegypti mosquitoes in Malaysia, 1966.