Swine H1n1 Influenza Update

Swine influenza USA/Mexico 2009 Information and advice as of 25th April 2009

WHO/WPRO

Swine Influenza A H1N1 Virology • •

Swine influenza H1N1 Reassortment - four different genes: – – – –

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North America swine Asia/Europe swine Human influenza Avian (Non H5)

Unique combination that has never been seen before Level of immunity in general community – Unknown

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Effectiveness of seasonal influenza vaccine – Unknown

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Antiviral resistance – Resistant to adamantines – Sensitive to tamiflu and relenza

WHO/WPRO

USA • 30 March first case (10y, M) – San Diego County - California • 28 March second case ( 9y, F) – Imperial County - California • As of 25 April – 8 cases – California (6) – Texas (2) – Guadalupe County & San Antonio County

• No contact with pigs • Human to human confirmed by USCDC WHO/WPRO

Location of outbreaks: USA

Imperial County, CA (border with Arizona)

San Diego CA

Guadalupe County, TX

San Antonio, TX WHO/WPRO

Mexico • Higher than expected ILI reports – March and April (usual peak in December) – Northern and central Mexico

• Steep rise in patients admitted with severe pneumonia in the following provinces in the past 10 days: – Baja, San Luis Potosi, Mexico City, Tlaxala, Hidalgo, Vera Cruz, Chihuahua

• Majority pneumonia cases aged 25 to 44 years old • Some deaths reported - majority in previously healthy adults • A number of pneumonia cases have tested positive for swine influenza WHO/WPRO

Location of outbreaks: Mexico

Hidalgo

WHO/WPRO

San Luis Potosi

Tlaxcala

Vera Cruz

Clinical Presentation (Mexico) • Incubation period – up to 7 days • Range of symptoms – very mild to severe acute respiratory symptoms • Vomiting and diarrhoea in some cases • Fatal cases: ill for 6 days then deteriorate and many needed ventilation WHO/WPRO

Advice to clinician – unaffected countries • Health Travellers who have acute respiratory symptoms and returned from within 7 days: – California, USA – Texas, USA – Mexico (all)

• Report as suspect case, arrange for testing, isolate • If positive – isolation, treatment with antivirals (tamiflu) and inform public health authorities so that contact tracing can be initiated WHO/WPRO

Advice: Infection Control Infection control for suspect or confirmed case of swine influenza: • Standard, Droplet and Contact precautions should be used for all patient care activities: e.g. frequent hands wash, wear disposable non-sterile gloves, gowns, and eye protection (e.g., goggles) to prevent conjunctival exposure.

WHO/WPRO

Advice – Surveillance Clinicians/Public Health Authorities Ensure immediate reporting of: • Suspect cases of swine influenza A (H1N1) – Suspect case: Acute respiratory illness with travel to affect area within 7 days of onset of illness

• Unusual patterns or clusters of respiratory disease Laboratory: • Immediate reporting of untypable influenza A • Send sample to reference laboratory • Inform public health so that investigation can be initiated WHO/WPRO

Laboratory detection of swine influenza H1N1 • Samples should be collected, handled, stored and shipped using protocols developed for influenza H5N1 • Virus isolation should only be carried out in facilities with BSL-3 or higher levels of containment • Most tests designed to detect influenza A virus SHOULD detect this strain • Some tests for subtyping MAY NOT identify this strain correctly WHO/WPRO

Laboratory detection of swine influenza H1N1 • To definitively confirm this as swine influenza A H1N1, sequencing of viral nucleic acid is recommended. This should be performed promptly. • WHO is currently identifying which laboratories in the region are capable of performing this procedure.

WHO/WPRO

Advice: Border control & International travel •

Health information and advice to international travellers – avoid exposure to infected persons – implement precautionary measures to prevent the disease (e.g. hand hygiene, cough etiquette etc) – if developing ILI or acute respiratory illness, limit contact with others, report local health authority and seek appropriate medical care

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WHO has not recommended border screening (e.g. entry/exit screening), but countries in the WPR may consider implementing entry screening based on national decision

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WHO has not recommended travel restrictions to the countries currently experiencing human swine influenza (Mexico and USA)

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WHO does not recommend international border closure WHO/WPRO

Advice to general public Our standard precautions remain in place: • Cover your cough or sneeze with a mask or a tissue or your sleeve • Maintain good personal hygiene. Wash your hands frequently and avoid touching your face. • Avoid obviously sick people • Stay at home if you are unwell • See your doctor if you have fever, cough, sore throat, body aches, headache, chills and fatigue.

Health information and advice to international travellers to affected areas When travelling • Avoid exposure to infected persons • Implement precautionary measures to prevent the disease (e.g. hand hygiene, cough etiquette etc) • If developing ILI or acute respiratory illness, limit contact with others, report local health authority and seek appropriate medical care If you are in or have traveled to an affected area: • Monitor your health • If you develop symptoms seek medical attention. Advise the healthcare facility that you have recently been in an area that has reported swine flu

Eating pork • Swine influenza viruses are not transmitted by food. You cannot get swine influenza from eating pork products. • Pork meat is safe to eat as long as it is handled appropriately and cooked thoroughly.