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Open Access Research

Viral aetiology influenza like illnesses in Santa Cruz, Bolivia (2010–2012)

Julie Delangue1*, Yelin Roca Sanchez2, Géraldine Piorkowski1, Maël Bessaud1, Cécile Baronti1, Laurence Thirion-Perrier1, Roxana Loayza Mafayle2, Cinthia Avila Ardaya2, Gabriela Añez Aguilera2, Jimmy Revollo Guzman2, Javier Lora Riera2 and Xavier de Lamballerie1

Author Affiliations

1 IRD French Institute of Research for Development, EHESP French School of Public Health, UMR_D 190 “Emergence des Pathologies Virales”, Aix Marseille Univ, 13005 Marseille, France

2 Inmunologia y Biologia molecular, Centro National de Enfermedades Tropicales, Av 26 de Febrero esquina Centenario 2do Anillo, Santa Cruz, Bolivia

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Virology Journal 2014, 11:35  doi:10.1186/1743-422X-11-35

Published: 24 February 2014

Abstract

Background

Acute respiratory infections represent a serious public health issue worldwide but virological aetiologies of Influenza Like Illnesses (ILIs) remain largely unknown in developing countries. This study represents the first attempt to characterise viral aetiologies of ILIs in Bolivia.

Methods

It was performed in Santa Cruz city from January 2010 to September 2012, based on 564 naso-pharyngeal swabs collected in a National Reference Laboratory and real-time PCR techniques, viral cultures and phylogenetic analyses.

Results

50.2% of samples were positive for at least one virus with influenza viruses (Flu A: ~15%; Flu B: ~9%), rhinoviruses (~8%), coronaviruses (~5%) and hRSV (~4%) being the most frequently identified. The pattern of viral infections varied according to age groups. The elucidation rate was the highest (>60%) amongst patients under 10 yo and the lowest (<40%) amongst patients ≥60 yo. Nearly 3% of samples showed dual viral infections. Epidemiological peaks were associated with a predominant virus but generally included 30-50% of infections by different viruses. Unexpectedly, the frequency of influenza in the 0–4 yo population was very low and a complete hRSV eclipse occurred in 2011. Genetic analyses indicated that distinct evolutionary lineages of Flu A(H1N1)pdm2009, Flu A/H3N2 and Flu B have co-circulated in Bolivia in the study period, originating from Central and North America, Europe, Asia and Australia.

Conclusion

Our results emphasise the requirement for a reinforced epidemiological and genetic follow-up of influenza and other ILIs in Bolivia to further inform the preparation of vaccines used in the region, guide vaccination campaigns and improve the medical management of patients.

Keywords:
Epidemiology; Influenza like illness; Bolivia; South America; Influenza A(H1N1)pdm2009; Influenza phylogeny; Respiratory infections