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. 2014 Jul;20(7):1162-9.
doi: 10.3201/eid2007.131869.

Epidemiology of influenza virus types and subtypes in South Africa, 2009-2012

Adam L Cohen, Orienka Hellferscee, Marthi Pretorius, Florette Treurnicht, Sibongile Walaza, Shabir Madhi, Michelle Groome, Halima Dawood, Ebrahim Variava, Kathleen Kahn, Nicole Wolter, Anne von Gottberg, Stefano Tempia, Marietjie Venter, Cheryl Cohen

Epidemiology of influenza virus types and subtypes in South Africa, 2009-2012

Adam L Cohen et al. Emerg Infect Dis. 2014 Jul.

Abstract

To determine clinical and epidemiologic differences between influenza caused by different virus types and subtypes, we identified patients and tested specimens. Patients were children and adults hospitalized with confirmed influenza and severe acute respiratory illness (SARI) identified through active, prospective, hospital-based surveillance from 2009-2012 in South Africa. Respiratory specimens were tested, typed, and subtyped for influenza virus by PCR. Of 16,005 SARI patients tested, 1,239 (8%) were positive for influenza virus. Patient age and co-infections varied according to virus type and subtype, but disease severity did not. Case-patients with influenza B were more likely than patients with influenza A to be HIV infected. A higher proportion of case-patients infected during the first wave of the 2009 influenza pandemic were 5-24 years of age (19%) than were patients infected during the second wave (9%). Although clinical differences exist, treatment recommendations do not differ according to subtype; prevention through vaccination is recommended.

Keywords: H1N1; H3N2; South Africa; influenza; influenza A; influenza B; pneumonia; subtypes; types; viruses.

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Figures

Figure
Figure
Number of case-patients hospitalized with influenza-associated severe acute respiratory illness, by week and virus strain at 4 sites, South Africa, 2009–2012.
See this image and copyright information in PMC

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