JNC VI and Influenza A (H5N1)
This article will highlight two important events. The first being JNC VI, which for the first time stratifies hypertension by blood pressure stage and into risk groups to guide treatment. The second being Influenza A (H5N1). This avian strain which normally affects poultery has "crossed-over" to infect humans. There is great concern that this strain might herald the next influenza pandemic.
New physician guidelines ( http://www.nhlbi.nih.gov/new/press/nhlbi-06.htm )for the prevention and treatment of high blood pressure were released recently by the National Heart, Lung, and Blood Institute (NHLBI). The guidelines, approved by the Coordinating Committee of the NHLBI's National High Blood Pressure Education Program, contain updated treatment strategies, including a system of stratifying patients into risk groups and the idea of compelling indications for certain antihypertensive medications.
The guidelines, known as The Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI), (http://www.nhlbi.nih.gov/nhlbi/cardio/hbp/prof/jncintro.htm)(down see JNC VII) also reveal a disturbing trend in the treatment and control of high blood pressure or hypertension and in the rates of associated diseases such as stroke and coronary heart disease (CHD).
One of the most significant changes in JNC VI, compared to the previous guidelines issued in 1992, is the concept of stratifying hypertension patients by blood pressure stage (1, 2, 3) and into risk groups (A, B, and C) to guide treatment decisions. These risk groups are based on the presence of risk factors like high blood cholesterol and on related organ damage. For example, a patient in Risk Group A with stage 1 hypertension (140-159 systolic and 90-99 diastolic) with no cardiovascular disease, organ damage, or other risk factors would try lifestyle changes for 1 year before taking drugs. By contrast, the earlier guidelines suggested that such patients should try lifestyle changes for only 3 to 6 months before starting medication. Regardless of risk group, JNC VI recommends lifestyle changes for all patients on drug therapy.
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[PDF document, 546 K] (http://www.nhlbi.nih.gov/nhlbi/cardio/hbp/prof/jnc6.pdf) (down) see JNC VII
The full text is also available in html format at Archives Internal Medicine ( http://archinte.ama-assn.org/ ) at http://archinte.ama-assn.org/cgi/content/abstract/157/21/2413 .
Influenza A Virus (H5N1)
WHO reported a new strain of influenza A(H5N1) in Hong Kong Special Administrative Region of China. The report is as follows
21 August 1997
WHO Press Release WHO/60
An influenza virus - type A(H5N1) - known previously to infect birds only, has been isolated in a 3 year-old boy who died in Hong Kong last May of Reye syndrome* during an acute respiratory illness.
However, this is the only case to have been detected so far in a human being. "There is no indication at present that this strain has spread from person to person. There is consequently no need for special measures to be taken, as of today," confirmed Dr Daniel Lavanchy of the World Health Organization's (WHO) Division of Emerging and other Communicable Diseases Surveillance and Control (EMC).
WHO is monitoring developments attentively, working in close collaboration with the Influenza Centre and the Department of Health in Hong Kong Special Administrative Region, with the four WHO Collaborating Centres for Reference and Research on Influenza in Atlanta, USA, London, UK, Melbourne, Australia, and Tokyo, Japan, and with the National Influenza Centre in the Netherlands.
Although no more instances of type A(H5N1) virus have been isolated from humans, efforts are being made to determine whether other persons in Hong Kong or other parts of southern China may have been infected with this strain. A team of scientists from a WHO Collaborating Centre (the Centers for Disease Control and Prevention (CDC) in Atlanta, USA) arrived in Hong Kong on 20 August and will conduct an extensive investigation in collaboration with the WHO Collaborating Centre at the National Institute of Infectious Diseases in Tokyo, Japan. They will assist the Influenza Centre and Department of Health in Hong Kong in assessing the significance of this discovery and its impact for public health.
* The Reye syndrome, involving the central nervous system and the liver, is a rare complication in children who may have ingested salicylates (i.e. Aspirin); it occurs mainly in children with influenza type B and less frequently in children with influenza type A or chickenpox.
8 December 1997
The Department of Health has informed WHO of two additional cases of influenza A(H5N1) diagnosed recently. One case was in a 54-year old man with influenza-like illness who died of lung complications. The second case was in a 13-year-old girl who is currently hospitalized in an intensive care unit where her condition is improving. Both cases were positive for H5N1. The source of infection is not known but neither had direct contact with the two cases previously reported. Samples have been sent to the Centers for Disease Control and Prevention (CDC) Atlanta, USA, and a CDC team is on site to support the investigations.
12 December 1997
Influenza A(H5N1) in Hong Kong Special Administrative Region of China (Update)
As of 12 December three suspected cases of influenza A(H5N1) are under investigation. Influenza surveillance has been intensified and now includes all hospitals and 63 public health clinics. The last two of the four confirmed cases had onset of illness on 20 and 24 November respectively. A team of five epidemiologists from the WHO Collaborating Centre for Influenza Reference and Research at the Centers for Disease Control and Prevention (CDC), Atlanta, USA are on site for investigations. Blood samples are being collected from family members of cases, nursing staff and other contacts. So far no case of person-to-person transmission has been identified but further tests of blood specimens are required to ascertain the origin of the infection with greater precision. Influenza-like illness has been noted in some nursing staff, now on amantadine treatment, but this could be due to other respiratory viruses currently circulating in Hong Kong. No current outbreak has been reported among animals but surveillance is being established in wild and domestic birds. There is no reason to impose travel restrictions or quarantine in Hong Kong or elsewhere.
In the absence of human-to-human transmission and of any documented outbreak, WHO does not recommend the development of a specific H5N1 vaccine. However, the WHO Collaborating Centres for Influenza are working with various H5 strains to prepare high growth reassortants which could be used for vaccine production, in case of need. The preparation of a vaccine strain may take several months while reagents for vaccine production could be ready, at the earliest, in January 1998. In the meantime, the WHO Collaborating Centre at CDC has prepared a kit of reagents which will be despatched shortly to all National Influenza Centres for diagnosis of H5N1. Work with the live pathogenic H5N1 virus will be restricted to laboratory containment level P3+ and strains will only be made available after assessment of the request by WHO in collaboration with the local safety committee and national veterinary and public health authorities
For more informatiuon and updates on the virus, I have setup a site at Influenza A(H5N1) (http://www.vadscorner.com/h5n1.html).
With that I let your "mouse" or your "keyboard" do the "talking".
Till next month, "Happy Surfing".
The links to URL mentioned above are valid at the time of writing (13 December 1997).
This page can be accessed at http://www.vadscorner.com/internet10.html or at http://www.vadscorner.com/mma_internet.html.
Links last updated 29 April 2005.