Pandemic Influenza (H1N1) 09 Swine Flu update
Although the number of new pandemic influenza cases in New Zealand is now low, the virus is still circulating and causing illness in our communities. It is therefore important that people stay alert to the signs and symptoms of disease, and that the health sector remains vigilant in case of any significant increase in cases.
The need for constant vigilance is being demonstrated by the unusually early start to the winter influenza season across many countries in Europe and Asia, as well as parts of the United States, Mexico and Canada.
New Zealanders travelling overseas should be aware of countries in which pandemic influenza is widespread, and take precautions by regularly washing and drying their hands and staying away from people who are sick. If travellers have any health conditions that may put them at risk from influenza, they should discuss this with their GP before travelling.
Individuals that have been identified as “at risk” of more complicated or severe illness associated with infection by the pandemic influenza virus include: pregnant women, infants and children under 5 years, patients who are severely obese or with chronic health conditions such as cardiovascular, respiratory or liver disease, or diabetes, and patients with immunosuppression related to treatment for cancer or due to other diseases.
We are alert to any signs of a second wave of this pandemic influenza virus as occurred in previous pandemics. We have taken stock of what we have learned from the first wave and there is considerable work already underway to be ready for any second wave.
International situation
The World Health Organization’s update as of 6 November 2009 cited over 482,300 laboratory-confirmed cases and at least 6071 deaths. Although active monitoring by WHO has so far detected no signs that the pandemic influenza virus has mutated to a more virulent form, infections in different animal species (pig, turkey, ferret, cat and mink) have been reported. WHO stressed that these infections were isolated events and pose no special risks to human health.
WHO also reported that influenza-like illness (ILI) due to the pandemic influenza virus continues to increase across many countries of Europe and central and western Asia as well as parts of North America. Visits to doctors for ILI in the US, Mexico and Canada exceeded levels seen over the past six flu seasons.
Temperate regions of the southern hemisphere (which includes New Zealand) report declining influenza activity.
Further information on the progress of the pandemic is available on the WHO website: http://www.who.int/csr/don/2009_11_06/en/index.html .
GP consultations
Data from the Institute of Environmental Science and Research’s sentinel general practice surveillance system show that visits to doctors for ILI continue to decline but are still slightly higher than the level recorded at the same time last year.
Graph of weekly rate of ILI GP presentations per 100,000 registered population for all ages For latest updates on Influenza A (H1N1) Swine Flu, visit http://www.moh.govt.nz
Healthline calls
Healthline has continued to receive a high number of influenza-related calls over the past weeks, although numbers have decreased since peaks in mid-June and early July. The total number of calls answered by Healthline nurses continues to be about 20 percent above normal levels.
GP Consultations
The data below is from Environmental Science and Research's (ESR) sentinel general practice surveillance system. It shows that at its peak, the weekly influenza-like illness (ILI) consultation rates this year were nearly three times higher than the winter peak experienced in the last two years. The number of ILI consultations has decreased over recent weeks, but there are different pictures of influenza activity across regions and across some age groups.
The WHO reports that transmission of the pandemic influenza (H1N1) 09 virus is declining globally, especially in temperate regions of the southern hemisphere (with the exception of South Africa). Active transmission is still seen in some later affected areas of Australia, Chile and Argentina even as national rates decrease.
The virus continues to spread in the northern hemisphere, although areas first affected by the virus are seeing less activity. Areas of tropical Asia are reporting increasing rates of illness. The H1N1 virus is now the dominant influenza strain in most parts of the world, and is expected to remain so during the coming northern hemisphere influenza season. The World Health Organization is no longer issuing tables showing the numbers of confirmed cases for all countries. This is because in many countries, laboratory testing is being carried out on only a small number of people and the numbers of confirmed cases no longer give an accurate picture of the spread and extent of the virus. For more information about this reporting change go to the WHO website:www.who.int/en/