Therapeutic approaches to cystic fibrosis: memorandum from a joint WHO/ICF(M)A meeting.

Cystic fibrosis is one of the commonest genetic diseases among Caucasians and represents an important cause of suffering and death among children and adults. In the past two decades marked prolongation of the life of patients with cystic fibrosis has been achieved as the result of improved case-finding and an extensive regimen of therapies. More recently, a variety of new approaches to therapy have been developed or proposed as the result of advances in cell physiology and molecular biology. This article summarizes the presentations and discussions made at a joint WHO/ICF(M)A (International Cystic Fibrosis (Mucoviscidosis) Association) meeting, held in Washington, DC, on 14 October 1992, and reviews the current status of possible therapies for cystic fibrosis and their implications for treatment in various countries of the world.     

Feasibility study of community control programmes for cystic fibrosis: memorandum from a WHO/ICF(M)A meeting.

As a result of improved medical services and diagnosis of cystic fibrosis (CF), it has in recent years become clear that this is a common genetic disorder with a worldwide distribution. The average life expectancy of CF patients is very low in the developing world, but in developed countries this fatal childhood disease is becoming a chronic disorder persisting into adult life. In western Europe and North America the average life expectancy is now about 25 years, with a fatal outcome, so that CF represents one of the most serious of inherited life-threatening conditions. It remains to be shown whether very early diagnosis and treatment can further improve the prognosis.     

Cervical cancer control in developing countries: memorandum from a WHO meeting.

This memorandum summarizes the report of a WHO Consultation on the Control of Cervical Cancer in Developing Countries, held on 6-7 November 1994, in New Delhi, India. Evaluated was the current situation with regard to cervical cancer and the relevance of current practices in screening. New pragmatic approaches to cervical cancer were proposed that are relevant for developing countries; this includes empowerment of women to come forward, and visual inspection-"downstaging".     

Use of intraocular lenses in cataract surgery in developing countries: memorandum from a WHO meeting.

Visual loss or disability from cataract represents a massive public health and socioeconomic problem in most developing countries. At present, some 13.5 million cases require treatment and this number will increase, as most countries in the Third World are unable to cope with both the backlog and new cases. Cataract extraction with intraocular lens (IOL) implantation is now the established and preferred method in industrialized countries. The introduction of IOLs in developing countries, however, depends on their having adequately trained manpower and facilities (equipment and supplies, including IOLs) for surgery. This will inevitably increase the cost per operated case which, despite the scarce resources for cataract surgery in many developing countries, may be justified by the improved restoration of the patient''s vision. Experience has led to the following generic designs for IOLs: the one-piece or three-piece C-loop polymethylmethacrylate (PMMA) posterior chamber lens, which is the current favourite; and, the flexible or rigid one-piece all-PMMA anterior chamber lens, which is a valid alternative in many situations. Further scientific evaluation of the use of these lenses in a wide variety of settings in developing countries is required. Operations research is also needed in order better to define and standardize the various steps and procedures in the surgical and post-operative management of IOL implantation in Third World settings. Meanwhile, the following should be available to ensure safe and good quality cataract surgery using IOLs in developing countries: properly trained surgeons; the needed facilities and equipment with regular supplies; a good quality lens of appropriate design; and the necessary means for careful follow-up of operated patients.     

Anthrax: memorandum from a WHO meeting.

The risk of anthrax can be reduced through international collaboration in health education and training, promotion of research, and provision of scientific and technical advice. These issues were discussed by a WHO Working Group on Anthrax in September 1995, and this Memorandum presents their priority concerns and recommendations in several areas: surveillance, epidemiology, diagnosis in humans and in animals, prevention and control, and international cooperation.     

Depot-medroxyprogesterone acetate (DMPA) and cancer: memorandum from a WHO meeting.

Depot-medroxyprogesterone acetate (DMPA) is a long-acting progestational contraceptive, which is administered by injection. It was developed in the mid-1960s, when it was seen as a method that would be particularly useful for women seeking reversible contraception who had difficulty taking a pill every day. DMPA has been shown to be a highly effective contraceptive, and it has proved acceptable in a variety of settings. The drug is licensed as a contraceptive in more than 90 countries and has been widely used in a number of them, such as Thailand and New Zealand. On a worldwide basis, the licensing, acceptability, and prevalence of use have been influenced by concern that DMPA may increase the risk of cancer. Cancer of the breast has been a particular concern. This Memorandum reviews comprehensively the results of toxicological tests in animals and epidemiological studies in humans concerning the carcinogenicity of DMPA.     

Emerging infectious diseases: memorandum from a WHO meeting.

A meeting of international experts exchanged information on recent activities dealing with new, emerging and re-emerging diseases, discussed ways of responding to this problem and to other communicable disease threats, and reviewed WHO''s activities and role in this area. This Memorandum summarizes the various presentations and concludes with the recommendations and specific tasks for action at every level.     

Current status of allergen immunotherapy (hyposensitization): memorandum from a WHO/IUIS meeting.

This Memorandum reviews the present status of allergen immunotherapy, its scientific basis, and the clinical evidence of its efficacy. It also makes recommendations on both indications and contraindications, the most appropriate allergens and treatment regimens, and on prevention and management of adverse reactions. Finally, it indicates future developments in this form of treatment.     

A standard international acupuncture nomenclature: memorandum from a WHO meeting.

The WHO Scientific Group to Adopt a Standard International Acupuncture Nomenclature met in Geneva from 30 October to 3 November 1989. The main features of the recommended nomenclature are the use of the English translation of the name of each meridian and an alphanumeric code derived from the English names, and the use of the Chinese phonetic alphabet (Pinyin) names and the Han character names of the meridians and acupuncture points. This standard nomenclature will facilitate the teaching, research and clinical practice of acupuncture, as well as exchange of information globally.     

Destruction of variola virus: memorandum from a WHO meeting.

This Memorandum discusses the fate of variola virus stocks which have been kept in two WHO Collaborating Centres, as well as cloned DNA fragments of variola virus genome, smallpox vaccine, and seed vaccinia virus for the production of this vaccine. General and specific recommendations are given concerning destruction of variola virus; storage, distribution and handling of cloned DNA fragments of variola virus genome; and about stocks of smallpox vaccine.     

Public health control of hepatitis A: memorandum from a WHO meeting.

Hepatitis A virus infection is a significant cause of morbidity in many parts of the world, and hepatitis A vaccines will be important tools for its prevention and control. This Memorandum reviews the basic features of the disease and its epidemiology, and considers the measures which are available for control and prevention, including hepatitis A vaccine. The use of this vaccine should be adapted to specific epidemiological circumstances existing within a geographical region, with special attention to the cost-effectiveness of immunization programmes.     

Alpha 1-antitrypsin deficiency: memorandum from a WHO meeting.

alpha 1-Antitrypsin (AAT) deficiency, also known as alpha 1-antiprotease inhibitor deficiency, is a disease caused by genetically determined AAT deficiency. It occurs as a result of inheritance of two protease inhibitor (PI) deficiency alleles from the AAT gene locus (designated PI) on chromosomal segment 14q32.1. The most common deficiency allele is PI*Z and a large majority of individuals with severe AAT deficiency are PI type ZZ. The disease occurs predominantly in white persons of European origin and its frequency in Europe and North America is comparable to that of cystic fibrosis (1 in 2000 to 1 in 7000.) Persons with AAT deficiency may have no clinical manifestations. Chronic obstructive pulmonary disease (COPD) with a high frequency of panacinar emphysema is the most prevalent clinical disorder associated with AAT deficiency and the most frequent cause of disability and death. Tobacco smoking is the major risk factor for developing COPD, which generally begins by the third decade of life, much earlier than "usual" COPD that occurs in AAT-replete individuals. Liver disease, the second most frequent clinical manifestation of AAT deficiency, typically presents as cholestasis in infancy but is usually not severe and generally remits by adolescence. Chronic liver disease develops infrequently, although AAT deficiency is the commonest cause of chronic liver disease in childhood. Cirrhosis and carcinoma of the liver affect at least 25% of AAT-deficient adults over the age of 50 years. AAT deficiency appears to be widely underdiagnosed and based on predicted gene frequencies even in the most intensely studied populations, only a small proportion of those predicted to have AAT deficiency have been diagnosed. Human AAT is available in limited quantity for augmentation therapy. This Memorandum summarizes the discussions and recommendations made by participants at a WHO meeting held in Geneva on 18-20 March 1996 to review existing knowledge about this highly prevalent genetic disorder, develop a strategy for enhancing awareness of it among health-care-givers and the general public, and explore new case-finding and disease-prevention strategies.     

Developments in pertussis vaccines: memorandum from a WHO meeting

The WHO memorandum outlines the present situation regarding pertussis vaccines, discusses ways to evaluate candidate vaccines, and identifies future research needs. Most existing whooping cough vaccines are whole-cell vaccines, combined with diphtheria and tetanus toxoid adsorbed on an aluminum or calcium carrier. As whole bacterial cells, they contain a complex array of at least 7 toxins and antigens, and display a narrow margin between potency and toxicity. The Japanese introduced an acellular vaccine, admittedly sometimes less potent, called the Precipitated Purified Pertussis Vaccine, in 1981. This material contains far less bacterial mass, notably less endotoxin, and consequently produces less fever, erythema and induration. WHO has not yet established minimum requirements for standardization; even the mouse potency assay may not be suitable. There are techniques, however, which will measure amounts of component antigens and toxicity. Conflicting results on assays of potency and immunogenicity will have to be resolved. Besides the obvious need for large clinical trials of defined vaccines, a whole range of research needs were suggested, from genetic studies of the organism to specific details of the host response. It is generally agreed that a less reactogenic and more effective pertussis vaccine is needed and feasible.     

Facts about once-a-month injectable contraceptives: memorandum from a WHO meeting.

This Memorandum reviews the results of research undertaken in animals and human subjects on once-a-month injectable contraceptives containing a progestogen and an estrogen, in particular the products Cyclofem and Mesigyna. Results from clinical trials, including effectiveness and side-effects, are evaluated and issues arising from health service research are discussed. The Memorandum concludes with a statement regarding the use of Cyclofem and Mesigyna as options for potential contraceptive users.     

Standardization and improvement of influenza surveillance: memorandum from a WHO/GEIG meeting.

The main objectives of influenza surveillance are early detection of influenza outbreaks and identification of the causative agent, collection and analysis of influenza morbidity and mortality data, and collection of influenza virus isolates and analysis of their antigenic characteristics. The true morbidity and mortality from influenza are difficult to estimate in most countries on the basis of only reports of influenza-like illnesses. Analysis and comparisons of the impact of influenza in different countries are also difficult because surveillance systems and methods vary from one country to another. This Memorandum describes generally applicable systems that could improve influenza surveillance.     

Laboratory support for poliomyelitis eradication: memorandum from a WHO meeting.

This Memorandum summarizes the conclusions and recommendations of the participants at the Consultation on Strategy for Isolation and Characterization of Poliovirus Strains and Surveillance of Wild Polioviruses held in Geneva, 28-30 November 1988.