Secondary Infections in Swine Flu.

Swine influenza is respiratory disease of pigs caused by type A influenza virus that causes regular outbreak in pigs. Human to human transmission occurs. Some people develop severe respiratory symptoms and need ventilator. Patients can get secondary bacterial infections in form of pneumonia if viral infections persist. Death of swine flu occurs due to secondary bacterial infections leading to bacterial pneumonias. Method : 369 patients having acute respiratory illness suspected to be suffering from swine flu were included. Real time reverse transcriptase polymerase chain reaction (RT-PCR) was performed on sputum samples or tracheal aspirates of 134 patients admitted in Hospital due to pneumonia. 90 of these patients were positive for swine flu by RT-PCR. Result : Among 90 patients 55 patients’ shows bacterial growth and 35 patients did not show any growth. Maximum patients 17 shows Klebseilla pneumoniae,17 show Staphylococcus aureus ,10 show Escherichia coli,8 show Pseudomonas aeruginosa and 3 patients show Streptococccus pneumoniae. Even after treatment, death of 36 patients occurred. Among these 36 patients, 19 had both, bacterial as well as swine flu infection and 17 patients had only swine flu infection. Conclusion : Secondary bacterial infections in swine flu patients were multiresistant to antibiotics were noted. Pneumonia caused by co-infection contributes to a severe rapidly progressive illness.

Oseltamivir-resistant influenza A(H1N1)pdm09 virus in southern Brazil

The neuraminidase (NA) genes of A(H1N1)pdm09 influenza virus isolates from 306 infected patients were analysed. The circulation of oseltamivir-resistant viruses in Brazil has not been reported previously. Clinical samples were collected in the state of Rio Grande do Sul (RS) from 2009-2011 and two NA inhibitor-resistant mutants were identified, one in 2009 (H275Y) and the other in 2011 (S247N). This study revealed a low prevalence of resistant viruses (0.8%) with no spread of the resistant mutants throughout RS.

Tools to Detect Influenza Virus

In 2009, pandemic influenza A (H1N1) virus (H1N1 09) started to spread quickly in many countries. It causes respiratory infection with signs and symptoms of common infectious agents. Thus, clinicians sometimes may miss the H1N1 patient. Clinical laboratory tests are important for the diagnosis of the H1N1 infection. There are several tests available, however, the rapid test and direct fluorescence antigen test are unable to rule out the influenza virus infection and viral culture test is time consuming. Therefore, nucleic acid amplification techniques based on reverse transcription polymerase chain reaction assays are regarded as a specific diagnosis to confirm the influenza virus infection. Although the nucleic acid-based techniques are highly sensitive and specific, the high mutation rate of the influenza RNA-dependent RNA polymerase could limit the utility of the techniques. In addition, their use depends on the availability, cost and throughput of the diagnostic techniques. To overcome these drawbacks, evaluation and development of the techniques should be continued. This review provides an overview of various techniques for specific diagnosis of influenza infection.

Virological surveillance and antiviral resistance of human influenza virus in Argentina, 2005–2008 / Vigilancia virológica y resistencia a los antivíricos del virus de la gripe humana en la Argentina, 2005–2008

Objective. To describe the virological characteristics of the influenza strains circulating in Argentina in 2005–2008 and to assess the prevalence of antiviral resistance. Methods. On the basis of their geographical spread and prevalence, influenza A and B isolates grown in Madin–Darby canine kidney cells were selected after antigenic and genomic characterization to be analyzed for antiviral resistance by enzymatic assay and pyrosequencing. Amantadine susceptibility was evaluated by pyrosequencing for known resistance markers on 45 strains of influenza A. Susceptibility to oseltamivir and zanamivir was evaluated by enzymatic assay of 67 influenza A and 46 influenza B strains, some of which were further analyzed by sequencing the neuraminidase gene. Results. Resistance to amantadine was observed only on A(H3N2) strains (29/33); all of them carried the mutation S31N in their M2 sequence. Oseltamivir resistance was observed in 12 (34.3%) of the 35 A(H1N1) strains from 2008; all of them carried the mutation H275Y in their neuraminidase sequence. All these viruses remained sensitive to zanamivir. Conclusions. This study describes a high incidence of amantadine-resistant influenza A(H3N2) viruses since 2006 and an unprecedented increase in oseltamivir resistance detected only in influenza A(H1N1) viruses isolated in 2008. Influenza A and B viruses were more sensitive to oseltamivir than to zanamivir, and influenza A viruses were more sensitive to both neuraminidase inhibitors than the influenza B viruses. The national data generated and analyzed in this study may help increase knowledge about influenza antiviral drug resistance, which is a problem of global concern.

Objetivo. Describir las características virológicas de las cepas de virus de la gripe que circulaban en la Argentina entre el 2005 y el 2008, y evaluar la prevalencia de la resistencia a los antivíricos. Métodos. Según su diseminación geográfica y su prevalencia, se seleccionaron aislados de gripe A y B cultivados en células renales caninas de Madin-Darby después de su caracterización antigénica y genómica, y se analizó su resistencia a los antivíricos mediante análisis enzimático y pirosecuenciación. La sensibilidad a la amantadina se evaluó por pirosecuenciación para los marcadores conocidos de resistencia en 45 cepas de gripe A. La sensibilidad al oseltamivir y al zanamivir se evaluó mediante análisis enzimático de 67 cepas de gripe A y 46 cepas de gripe B, algunas de las cuales se analizaron en mayor profundidad mediante la secuenciación del gen de la neuraminidasa. Resultados. Se observó resistencia a la amantadina solo en las cepas de gripe A (H3N2) (29/33); todas ellas tenían la mutación S31N en su secuencia de M2. Se observó resistencia al oseltamivir en 12 (34,3%) de las 35 cepas de gripe A (H1N1) aisladas en el 2008; todas ellas tenían la mutación H275Y en su secuencia de neuraminidasa. Todos estos virus conservaron su sensibilidad al zanamivir. Conclusiones. En este estudio se describe una incidencia elevada del virus de la gripe A (H3N2) resistente a la amantadina desde el 2006 y un aumento sin precedentes de la resistencia al oseltamivir detectada solo en los virus de la gripe A (H1N1) aislados en el 2008. Los virus de la gripe A y B fueron más sensibles al oseltamivir que al zanamivir y los virus de la gripe A fueron más sensibles a ambos inhibidores de la neuraminidasa que los virus de la gripe B. Los datos nacionales generados y analizados en este estudio pueden ayudar a aumentar los conocimientos acerca de la resistencia a los fármacos antivíricos dirigidos contra el virus de la gripe, lo que es un motivo de preocupación mundial.

Prevalence of oseltamivir-resistant 2009 H1N1 influenza virus among patients with pandemic 2009 H1N1 influenza infection in NRITLD, Tehran, Iran

Oseltamivir-resistant cases were reported during the 2009 pandemic influenza outbreak and therefore, widespread emergence of oseltamivir-resistant 2009 H1N1 virus is imaginable. Underlying medical conditions like immunosuppression increase the chance of oseltamivir resistance. In a retrospective cross-sectional study, respiratory tract specimens of confirmed cases of 2009 H1N1 influenza referred to the Masih Daneshvari Hospital were analyzed for presence of H275Y mutation. From November 2009 through March 2010, oseltamivir-resistant 2009 H1N1 infection was observed and confirmed in 4 patients [including 2 immunocompromised patients] by performing H275Y mutation molecular testing. Close monitoring of resistance to neuraminidase inhibitors is essential in tertiary care centers. The H275Y mutation [oseltamivir-resistant genotype] could appear in the absence or presence of selective drug pressure

First oseltamivir-resistant pandemic [H1N1] 2009 influenza virus from the EMR

Yemen reported its first oseltamivir resistant pandemic [H1N1] 2009 virus in October 2009. This is also the first case of oseltamivir resistance virus reported from the Eastern Mediterranean Region. The specimen was taken from a 3 year old female child who was admitted to the hospital on 07 October with high grade of fever, cough, sore throat, body ache and difficulty in breathing. The child is also a known case of congential heart disease with pulmonary hypertension. The child was put on antiviral medicine and was tested positive for H1N1 by RT-PCR on 9 October at the National Public Health Laboratory of Yemen. The clinical condition of the child did not improve even 10 days after she was put on treatment. At this stage, her second nasal swab was tested positive for H1N1. The isolate was sent to NAMRU-3 [WHO CC] for routine antiviral resistance test and found to be resistant to oseltamivir. The patient has now clinically improved with no fever and difficulty in breathing