Microsoft word - human infection with influenza a _h7n9_ 15 april 2013 final.docx

Human infection with novel influenza A(H7N9) virus, 15 April 2013 Update This report includes updated case numbers in the section "Update on case numbers" and is otherwise similar to the report published on 10/04/2013. Background Influenza A H7 viruses are a group of influenza viruses that normally circulate among birds. The influenza A(H7N9) virus is one subgroup among the larger group of H7 viruses. Although some H7 viruses (H7N2, H7N3 and H7N7) have occasionally been found to infect humans, no human infections with H7N9 viruses had ever been reported until cases were detected in China on 29 March 2013 (http://www.who.int/csr/don/2013_04_01/en/index.html). The first case of disease was identified on 19 February 2013, reported from an 87 year old man who developed a respiratory infection and died on the 4 March 2013. Update on case numbers Since the last report dated 10 April 2013 – an additional 36 cases and 6 deaths have been reported. The virus has been identified from 2 additional provinces in China, Henan and Beijing. As of 14 April 2013, a total of 60 human cases of novel influenza A(H7N9) infection, including 13 deaths have been confirmed. Of these, 24 were from Shanghai, 16 from Jiangsu, 15 from Zhejiang, 2 from Anhui, 2 from Henan and one from Beijing. (http://www.promedmail.org/). Clinical presentation Symptoms of A(H7N9) are influenza-like, including fever, cough and shortness of breath. Most cases presented with respiratory tract infection that progressed to severe pneumonia associated with breathing difficulties in some cases. However, information is still limited about the full spectrum of disease that infection with influenza A(H7N9) virus might cause. Source of infection and transmission To date there is no evidence of person-to-person or healthcare-associated transmission. Close contacts of the confirmed cases are being closely monitored. Thus far, none of them has tested positive for A(H7N9) virus. The source of infection has not yet been confirmed. A number of the human H7N9 cases in China have reportedly had contact with domestic poultry. The Chinese authorities are conducting an extensive surveillance programme in domestic livestock in provinces where human cases have been found to gather further information. Some of the confirmed cases had contact with animals or with an animal environment. Chinese authorities have reported detection of A(H7N9) virus in samples collected from chickens, quails, ducks and pigeons at live bird markets in areas where humans have been affected. It is not yet known how persons became infected. The possibility of animal-to-human transmission and human-to-human transmission is being investigated. Advice to clinicians Clinicians should consider the possibility of novel influenza A (H7N9) virus infection in persons hospitalised with severe respiratory illness and an appropriate travel or exposure history: A patient who has had recent travel (within ≤ 10 days of illness onset) to a country where human cases of novel influenza A (H7N9) virus have recently been detected (currently only China) or where novel influenza A (H7N9) viruses are known to be circulating in animals. A patient who has had recent contact (within ≤ 10 days of illness onset) with a confirmed or probable case of infection with novel influenza A (H7N9) virus. Case Definitions - Confirmed case: A patient with novel influenza A (H7N9) virus infection that is confirmed by National Institute for communicable Diseases' (NICD's) Influenza Laboratory. - Probable case: A patient with illness compatible with influenza for whom laboratory diagnostic testing is positive for influenza A, negative for H1, negative for H1pdm09, and negative for H3 by real-time reverse transcriptase polymerase chain reaction (RT-PCR) – i.e. influenza A which is not subtypeable. - Case under investigation: A patient with illness compatible with influenza meeting either of the exposure criteria detailed above, and for whom laboratory confirmation is not known or pending, or for whom test results do not provide a sufficient level of detail to confirm influenza A(H7N9) virus infection. Samples for testing and interpretation of results Clinicians should obtain a nasopharyngeal and oropharyngeal swab or a nasopharyngeal aspirate from any patient that meets the criteria above. A bronchoalveolar lavage (BAL) specimen can also be taken from patients who are intubated. Specimens should be placed in viral transport medium and transported on ice to the National Institute for Communicable Diseases (NICD) for testing. All cases must be discussed with the NICD doctor on call at 082 883 9920 prior to submitting specimens. For additional guidance on diagnostic testing of patients under investigation for novel influenza A(H7N9) virus infection, please contact the Centre for Respiratory Diseases and Meningitis (CRDM) laboratory at the NICD at 011 5550478/011-3866412/011-3866392 during office hours or the NICD doctor on call after hours. The NICD will screen cases for Influenza A and subtype cases that are not seasonal human influenza viruses with H7 real-time PCR for avian influenza. Commercially available rapid influenza diagnostic tests (RIDTs) may not detect avian or variant influenza A viruses in respiratory specimens and are not recommended. Therefore, a negative rapid influenza diagnostic test result does not exclude infection with influenza viruses. In addition, a positive laboratory test result for influenza A cannot confirm variant or avian influenza virus infection because these tests cannot distinguish between influenza A virus subtypes (i.e.

they do not differentiate between human influenza A viruses and avian or variant viruses). These should be sent to NICD for subtyping. Prevention and Treatment 1. No vaccine is currently available for this subtype of the influenza virus. Preliminary test results provided by the WHO Collaborating Centre in China suggest that the virus is susceptible to the neuraminidase inhibitors (oseltamivir and zanamivir). 2. For persons hospitalised with suspected influenza, including suspected influenza A(H7N9) virus infection, clinicians should start empiric treatment with influenza antiviral medications (oral oseltamivir or inhaled zanamivir) as soon as possible, without waiting for laboratory confirmation. 3. For patients at risk for developing complicated or severe influenza and its complications with suspected influenza of any severity, (including suspected novel H7N9 virus infection), clinicians should start empiric treatment with influenza antiviral medications (oral oseltamivir or inhaled zanamivir) as soon as possible, without waiting for laboratory confirmation. 4. Antiviral treatment is most effective when started as soon as possible after influenza illness onset. Early initiation of treatment provides a more optimal clinical response, although treatment of moderate, severe, or progressive disease begun after 48 hours of symptoms may still provide benefit. Precautions and infection prevention and control considerations Public prevention measures include good hygiene and hand-washing practice, and special care and protection in dealing with dead animals. Influenza viruses are not transmitted through consuming well-cooked food. Because influenza viruses are inactivated by normal temperatures used for cooking, it is safe to eat properly prepared and cooked meat, including from poultry and game birds. Healthcare professionals (HCP) should be aware of appropriate infection prevention and control guidelines for patients under investigation for infection with novel influenza A viruses. Because it has been shown to cause severe respiratory illness in cases identified so far, HPC caring for patients under investigation for novel influenza A (H7N9) virus infection should adhere to standard precautions as well as droplet, contact, and airborne precautions (including eye protection), until more is known about the transmission characteristics of the A (H7N9) virus. Persons in contact with birds with suspected avian Influenza infection or working with avian influenza viruses should practice BSL2+infection control precautions. Viruses in the H5, H7 and H9 subtypes should not be cultured outside of a BSL-3 laboratory. Approved animal and human influenza laboratories may do molecular diagnosis of these viruses in a BSL-2 laboratory with BSL-3 precautions after inactivation of these viruses. The World Health Organization (WHO) does not advise special screening at points of entry with regard to this event, nor does it recommend that any travel or trade restrictions be applied. Additional information and resources on human infection with influenza A(H7N9) 1. Human infection with influenza A(H7N9) virus in China, 2. Frequently Asked Questions on human infection with influenza A(H7N9) virus, China 3. Human infection with influenza A(H7N9) virus in China accessed at 4. The Chinese Centre for Disease Control and prevention website: 5. Human infection with influenza A(H7N9) virus in China-update 6. Human infection with influenza A(H7N9) virus in China-update 7. Interim Guidance on Case Definitions to be Used for Novel Influenza A (H7N9) Case Investigations in the United States http://www.cdc.gov/flu/avianflu/h7n9-case- 11. http://www.promedmail.org/ 12. Alert On Human Infection With Novel Influenza A(H7N9) Virus accessed at

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