Nosocomial Co-Transmission of Avian Influenza A(H7N9) and A(H1N1)pdm09 Viruses between 2 Patients with Hematologic Disorders

Abstract

A nosocomial cluster induced by co-infections with avian influenza A(H7N9) and A(H1N1)pdm09 (pH1N1) viruses occurred in 2 patients at a hospital in Zhejiang Province, China, in January 2014. The index case-patient was a 57-year-old man with chronic lymphocytic leukemia who had been occupationally exposed to poultry. He had co-infection with H7N9 and pH1N1 viruses. A 71-year-old man with polycythemia vera who was in the same ward as the index case-patient for 6 days acquired infection with H7N9 and pH1N1 viruses. The incubation period for the second case-patient was estimated to be <4 days. Both case-patients died of multiple organ failure. Virus genetic sequences from the 2 case-patients were identical. Of 103 close contacts, none had acute respiratory symptoms; all were negative for H7N9 virus. Serum samples from both case-patients demonstrated strong proinflammatory cytokine secretion but incompetent protective immune responses. These findings strongly suggest limited nosocomial co-transmission of H7N9 and pH1N1 viruses from 1 immunocompromised patient to another.

Keywords: A(H1N1)pdm09; A(H1N1)pdm2009; H1N1; H7N9; chronic lymphocytic leukemia; cluster; co-infection; hematologic disorders; human-to-human transmission; immunocompromised; influenza; nosocomial transmission; pH1N1; pandemic; polycythemia vera; viruses; zoonoses.

Figure 1

Timeline of pertinent exposures, dates of illness onset, and virologic findings for 2 patients (index case-patient and case-patient 2) who were co-infected with avian influenza A(H7N9) and A(H1N1)pdm09, and 3 non–H7N9-infected patients who shared the same hematology ward, Taizhou Hospital (hospital A), Zhejiang Province, China, January 10–15, 2014. Orange box indicates the period when patients 2–5 were exposed to the index case-patient. Blue line indicates that the period when the 3 non–H7N9-infected patients (3–5) were exposed to case-patient 2. Index case-patient was a 57-year-old man with confirmed co-infection with H7N9 and pH1N1 viruses. Case-patient 2 was a 71-year-old-man also with confirmed co-infection with H7N9 and pH1N1 viruses. Patient 3 was a 78-year-old man with chronic B lymphoma cell leukemia. Patient 4 was a 50-year-old man with acute myeloid leukemia. Patient 5 was a 61-year-old man with macroglobulinemia. H7N9, avian influenza A(H7N9) virus; HI, hemagglutination inhibition; ICU, intensive care unit; LPM, live bird market; NPPV, noninvasive positive pressure ventilation; pH1N1, influenza A(H1N1)pdm09 virus; rRT-PCR, real-time reverse transcription PCR.

Figure 2

Schematic floor plan of the hematology ward where 2 case-patients with confirmed avian influenza A(H7N9) and A(H1N1)pdm09 virus co-infection and 1 non–H7N9-infected patient stayed, Taizhou Hospital, Zhejiang Province, China, January 10–15, 2014. The room was 22.4 m² (6.4 m × 3.5 m) in floor area, with 1 door (30 cm × 40 cm) and 1 window (105 cm × 20 cm), and 0.6 m of space separated the beds of the patients. H7N9, avian influenza A(H7N9) virus; pH1N1, influenza A(H1N1)pdm09 virus.