Influenza A/H3N2 virus infection in immunocompromised ferrets and emergence of antiviral resistance.

Rueshandra Roosenhoff,Koert J Stittelaar,Saskia L Smits,Anne Van Der Linden,Geert Van Amerongen,Ron A M Fouchier,Martin Schutten,Erhard Van Der Vries,Balaji Manicassamy

doi:10.1371/journal.pone.0200849

Rueshandra Roosenhoff, Koert J Stittelaar + Show 7 more

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https://doi.org/10.1371/journal.pone.0200849

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Abstract

Influenza viruses can cause severe life threatening infections in high-risk patients, including young children, the elderly and patients with compromised immunity due to underlying medical conditions or immunosuppressive treatment. The impaired immunity of these patients causes prolonged virus infection and combined with antiviral treatment facilitates the emergence of viruses with resistance mutations. The diverse nature of their immune status makes them a challenging group to study the impact of influenza virus infection and the efficacy of antiviral therapy. Immunocompromised ferrets may represent a suitable animal model to assess influenza virus infection and antiviral treatment strategies in immunocompromised hosts. Here, ferrets were given a daily oral solution of mycophenolate mofetil, tacrolimus and prednisolone sodium phosphate to suppress their immune system. Groups of immunocompromised and immunocompetent ferrets were inoculated with an A/H3N2 influenza virus and were subsequently treated with Oseltamivir or left untreated. Quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) was performed on the throat and nose specimens to study virus replication during the course of infection. All immunocompromised ferrets had prolonged presence of viral RNA and a higher total amount of virus shedding compared to the immunocompetent ferrets. Although Oseltamivir reduced the total amount of virus shedding from the nose and throat of treated ferrets, it also resulted in the emergence of the neuraminidase R292K resistance substitution in all these animals, as determined by mutation specific RT-PCR and next-generation sequencing. No additional mutations that could be associated with the emergence of the R292K resistance mutation were detected. The immunocompromised ferret model can be used to study A/H3N2 virus shedding and is a promising model to study new antiviral strategies and the emergence of antiviral resistance in immunocompromised hosts.

Highlights

Influenza viruses cause infections in millions of individuals worldwide every year
Ferrets were treated with a cocktail of mycophenolate mofetil, tacrolimus and prednisolone sodium phosphate for 3 days, which was previously shown to cause a steady-state of severe immunosuppression, which was continued by bi-daily dosing until the end of the experiment (S2 Fig) [5, 30]
In this group of ferrets, viral RNA was detected in the throat and nose throughout the 18 days of the experiment, as in ferrets that were not treated with Oseltamivir

Summary

Introduction

Influenza viruses cause infections in millions of individuals worldwide every year. In most cases, infected patients develop mild clinical symptoms associated with modest virus shedding that usually resolves within one to two weeks. Various studies have shown that patients with suppressed immunity due to diseases such as acquired immune deficiency syndrome (AIDS) and autoimmune disorders or due to the use of immunosuppressive drugs e.g. for chemotherapy or solid organ transplantation have an increased risk to develop serious complications following influenza virus infection [1, 4, 5]. Due to their impaired immune status, they are unable to clear viruses efficiently. Influenza viruses tend to persist longer and may cause prolonged life threatening infection in these immunocompromised hosts [5,6,7,8]

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