Tuesday, April 28, 2009

Swine influenza: Technical Information & Updates

(Source: WHO, OIE; Transferred by WVA and Modulated by NVA)

In response to cases of swine influenza A (H1N1), reported in Mexico and the United States of America, the Director-General convened a meeting of the Emergency Committee to assess the situation and advise her on appropriate responses.

The establishment of the Committee, which is composed of international experts in a variety of disciplines, is in compliance with the International Health Regulations (2005). The first meeting of the Emergency Committee was held on Saturday 25 April 2009. After reviewing available data on the current situation, Committee members identified a number of gaps in knowledge about the clinical features, epidemiology, and virology of reported cases and the appropriate responses. The Committee advised that answers to several specific questions were needed to facilitate its work. The Committee nevertheless agreed that the current situation constitutes a public health emergency of international concern. Based on this advice, the Director-General has determined that the current events constitute a public health emergency of international concern, under the Regulations.

Concerning public health measures, in line with the Regulations the Director-General is recommending, on the advice of the Committee, that all countries intensify surveillance for unusual outbreaks of influenza-like illness and severe pneumonia. The Committee further agreed that more information is needed before a decision could be made concerning the appropriateness of the current phase 3.



Swine flu illness in the United States and Mexico - update 2

26 April 2009 -- As of 26 April 2009, the United States Government has reported 20 laboratory confirmed human cases of swine influenza A/H1N1 (8 in New York, 7 in California, 2 in Texas, 2 in Kansas and 1 in Ohio). All 20 cases have had mild Influenza-Like Illness with only one requiring brief hospitalization. No deaths have been reported. All 20 viruses have the same genetic pattern based on preliminary testing. The virus is being described as a new subtype of A/H1N1 not previously detected in swine or humans.

Also as of 26 April, the Government of Mexico has reported 18 laboratory confirmed cases of swine influenza A/H1N1. Investigation is continuing to clarify the spread and severity of the disease in Mexico. Suspect clinical cases have been reported in 19 of the country's 32 states.

WHO and the Global Alert and Response Network (GOARN) are sending experts to Mexico to work with health authorities. WHO and its partners are actively investigating reports of suspect cases in other Member States as they occur, and are supporting field epidemiology activities, laboratory diagnosis and clinical management.

On Saturday, 25 April, upon the advice of the Emergency Committee called under the rules of the International Health Regulations, the Director-General declared this event a Public Health Emergency of International Concern.

WHO is not recommending any travel or trade restrictions.

For more details, click to :

Swine Influenza : http://www.who.int/csr/disease/swineflu/en/index.html

Current WHO phase of pandemic alert : http://www.who.int/csr/disease/avian_influenza/phase/en/index.html

International Health Regulations (IHR) : http://www.who.int/ihr/en/index.html

Pandemic Influenza Preparedness and Response (A WHO Guidance Document) :

http://whqlibdoc.who.int/publications/2008/9789241580410_eng.pdf

Guidance to Influenza Laboratories. Diagnosing Swine Influenza A/H1N1 Infections of current concern: http://www.who.int/csr/disease/swineflu/swineflu_guidance_labs_20090425.pdf

Interim WHO guidance for the surveillance of human infection with swine influenza A(H1N1) virus

http://www.who.int/csr/disease/swineflu/WHO_case_definition_swine_flu_2009_04_26.pdf

Q&A: Swine flu

Infection control experts are scrambling to respond to outbreaks of swine flu in Mexico and the US, and suspected cases elsewhere.

What is swine flu?

Swine flu is a respiratory disease which infects pigs.

Caused by influenza type A, there are regular outbreaks among herds of pigs, where the disease causes high levels of illness but is rarely fatal.

It tends to spread in autumn and winter but can circulate all year round.

There are many different types of swine flu and like human flu, the infection is constantly changing.

Can humans catch swine flu?

Swine flu does not normally infect humans, although sporadic cases do occur - usually in people who have had close contact with pigs.

There have also been rare documented cases of humans passing the infection to other humans.

Human-to-human transmission of swine flu is thought to spread in the same way as seasonal flu - through coughing and sneezing.

In the latest outbreak it is clear that the disease is being passed from person to person.

Symptoms of swine flu in humans appear to be similar to those produced by standard, seasonal flu.

Is this a new type of swine flu?

The World Health Organization has confirmed that at least some of the cases are a never-before-seen version of the H1N1 strain of influenza type A.

H1N1 is the same strain which causes seasonal outbreaks of flu in humans on a regular basis.

But this latest version of H1N1 is different: it contains genetic material that is typically found in strains of the virus that affect humans, birds and swine.

Flu viruses have the ability to swap genetic components with each other, and it seems likely that the new version of H1N1 resulted from a mixing of different versions of the virus, which may usually affect different species, in the same animal host.

Is it safe to eat pig meat?

Yes. There is no evidence that swine flu can be transmitted through eating meat from infected animals.

However, it is essential to cook meat properly. A temperature of 70C (158F) would be sure to kill the virus.

How worried should people be?

When any new strain of flu emerges that acquires the ability to pass from person to person, it is monitored very closely in case it has the potential to spark a pandemic.

The World Health Organization has warned that taken together the Mexican and US cases could potentially trigger a global pandemic, and stress that the situation is serious.

However, it is stressed that it is still too early to accurately assess the situation fully.

Currently, they say the world is closer to a flu pandemic than at any point since 1968 - rating the threat at three on a six-point scale.

Nobody knows the full potential impact of the pandemic, but experts have warned that it could cost millions of lives worldwide. The Spanish flu pandemic, which began in 1918, and was also caused by an H1N1 strain, killed millions of people.

The fact that all the cases in the US have so far produced mild symptoms is encouraging. It suggests that the severity of the Mexican outbreak may be due to an unusual geographically-specific factor - possibly a second unrelated virus circulating in the community - which would be unlikely to come into play in the rest of the world.

However, the fact that many of the victims are young does point to something unusual. Normal, seasonal flu tends to affect the elderly disproportionately.

What about treatments and vaccines?

The US authorities say that two drugs commonly used to treat flu, Tamiflu and Relenza, seem to be effective at treating cases that have occurred there so far.

It is unclear how effective currently available flu vaccines would be at offering protection against the new strain, as it is genetically distinct from other flu strains.

US scientists are already developing a bespoke new vaccine, but it may take some time to perfect it, and manufacture enough supplies to meet what could be huge demand.

What about bird flu?

The strain of bird flu which has caused scores of human deaths in South East Asia in recent years is a different strain to that responsible for the current outbreak of swine flu.

The latest form of swine flu is a new type of the H1N1 strain, while bird, or avian flu, is H5N1.

Experts fear H5N1 hold the potential to trigger a pandemic because of its ability to mutate rapidly. However, up until now it has remained very much a disease of birds. Those humans who have been infected have, without exception, worked closely with birds, and cases of human-to-human transmission are extremely rare - there is no suggestion that H5N1 has gained the ability to pass easily from person to person.

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