SciDev.Net

The third IPCC assessment report, Climate Change 2001, includes this section on the links between climate change and health. It offers a detailed look at how variations in climate, such as temperature or rainfall, could affect vector-borne disease. In particular, it evaluates computer models that predict climate impact on dengue fever and malaria. The assessment also looks at specific diseases such as leishmaniasis or schistosomiasis, explaining how the disease is spread and how changes in the environment might alter that spread.

The authors take a holistic look at the various factors involved. For example, in assessing schistosomiasis, they also consider the irrigation systems that will likely be needed to cope with expected water shortages resulting from climate change. The schistosomiasis parasite uses water snails as an intermediate host, so irrigation systems will need to be designed in such a way that they do not cause snail populations to multiply.

An update to the research on climate and vector-borne disease is also included in the fourth IPCC assessment report[796kB] although not in as much detail.

This Nature paper reviews evidence that a changing climate poses significant health risks and that global warming over the past few years has already increased illness and death worldwide.

Infectious diseases are strongly affected by climatic variations because the vectors that carry the bacteria or viruses do not have thermoregulatory mechanisms, say the authors. One of the most important existing sources of climatic variability is El Niño. This weather system has been shown to influence malaria in South America, rift valley fever in east Africa, cholera in Bangladesh and dengue fever in Thailand. If, as some scientists have suggested, climate change alters El Niño, the consequences will be significant.

The authors say there are some promising early warning systems for infectious disease. In Botswana, for example, two-thirds of the inter-annual variability of malaria can be predicted from sea surface temperatures and monthly rainfall.

As global temperatures rise, vector-borne disease is set to increase in the developing world but patterns will vary across countries. This review looks at how the prevalence of vector-borne disease will change in Africa, Asia, Australia, Europe, North America and South America.

As the authors explain, urbanisation levels will determine which diseases are likely to hit hardest. For example, dengue fever is a largely urban disease and will affect South America, where over 70 per cent of the population live in cities, far more than it will Sub-Saharan Africa, where less than 30 per cent of people live in urban areas. Malaria, by contrast, will have a bigger impact in Africa.

As ecosystems change, so will the distribution of vector species. Some will find their habitats expanded. A positive note is that most vectors cannot survive above about 40 degrees Celsius, so regions in which warming tips the temperature over this level could well see a drop in vector-borne disease — this is starting to be seen in Senegal, for example.

But the precise extent to which climate variability affects vector-borne disease is yet unknown, say the authors, which hampers evidence-based policy change.

This report provides a policy framework for assessing the impacts of climate change on health, including vector-borne disease, by considering five challenges: informational, poverty and equity-related, technological, sociopolitical and institutional.

It begins with a detailed outline of climate science so far and the financial cost of adaptation. The informational challenges relate to better monitoring and surveillance to gather urgently needed data on disease and mortality in different regions, and early warning systems to predict extreme weather events and associated disease outbreaks. Technological challenges include the development of vaccines for diseases such as malaria and dengue fever.

How do policymakers tackle such challenges? A key move will be for government and non-government agencies, academia and civil society to collaborate internationally. Surveillance and primary health information systems in developing countries must be improved and local communities need to share adaptation strategies.

Adapting to climate change also means investing in food security, clean water supplies and reforestation. Policymakers also need to stimulate industry to develop low-cost methods for recycling wastewater and desalinating sea water. Mitigating and adapting to climate change, say the authors, has become inextricable from policies to eradicate poverty or closing the gap on social inequalities and health.

This article, published by the WHO, answers frequently asked questions about the A(H1N1) influenza virus, or 'swine flu'. It provides information on the availability, production and effectiveness of A(H1N1) vaccines.

The WHO says that no effective A(H1N1) vaccines are currently available (May 2009) but adds that work is underway to develop one. The Centers for Disease Control and Prevention in the United States, for example, has identified and prepared candidate vaccine strains and is distributing them to all interested parties on request.

A vaccine could be available in five to six months after a pandemic strain has been identified but the WHO notes that more than 90 per cent of the global capacity for vaccine production lies in Europe or the United States — which may have implications for vaccinating people in developing countries. While these countries are well-versed in distributing vaccines through mass campaigns, they may face difficulties in ensuring timely access to enough supplies of vaccine.

This article, published by the WHO, assesses the potential for a global pandemic of A(H1N1) influenza, or 'swine flu'. The authors outline the properties of influenza viruses that are needed to create a pandemic and discuss population vulnerability and pandemic severity. They highlight the populations at most risk, for example people with underlying conditions such as cardiovascular disease, and the role that nutritional status and the quality of health services can play in influencing a pandemic's severity.

In assessing the 2009 swine flu outbreak, they draw attention to the fact that mutations often occur in influenza viruses, which means that while the emerging virus may be mild, it could return in several months in a much more lethal form.

The authors say that A(H1N1) is a new influenza virus not previously seen in humans or animals. They suggest that it is more contagious than seasonal flu, but note that outside Mexico where the outbreak began, the virus is causing very mild illness in otherwise healthy people. They emphasise the risk to people suffering from other chronic diseases and note that the WHO estimates that 85 per cent of these people are in developing countries.

This timeline, published by Nature, lists key dates and events in the 2009 outbreak of A(H1N1) influenza, or 'swine flu'. Drawing on information from the WHO, the US Centers for Disease Control and Prevention and others, it details confirmed and reported cases of A(H1N1), highlights the geographical spread of the virus and links to official documentation and key research findings as they are released.

This fact sheet from the WHO outlines the basics about swine influenza, or "swine flu", including what it is, what its implications are for human health and how people become infected.

To protect yourself from swine flu, the WHO recommends avoiding contact with sick pigs or people, washing your hands regularly, practicing good health habits and following advice from local health authorities.

This paper, written by an international team of researchers, documents the work of the African AIDS Vaccine Programme (AAVP). It highlights the programme's impacts, successes and challenges, and looks to where the AAVP is heading.

The AAVP, supported by the WHO and UNAIDS, is a network of African HIV vaccine stakeholders that promotes a coordinated approach to developing HIV vaccines and making them available on the continent. It operates through collaborative centres located at key institutions across Africa.

Programme members work on crucial issues including regulation; ethics, laws and human rights in clinical trials; biomedical research; country-based strategic planning; and communication and media.

The authors outline the AAVP's achievements to date, highlighting its success in expanding training and infrastructure specific to HIV vaccine development. They suggest that AAVP could offer a way for African stakeholders to influence the global agenda for HIV vaccine research and development.

Cardiovascular disease accounts for 30% of deaths worldwide and 10% of all years of healthy life lost to disease, and the figures are nearly as high in developing countries — 27 per cent and 9 per cent respectively. This compares with 10% of lives lost worldwide from HIV/AIDS, TB and malaria put together (12% in developing countries). So why have donors not invested as heavily into tackling non-communicable chronic diseases as they have with infectious ones? The authors of this article suggest several reasons: infectious diseases are in some ways easier to solve by a vaccine or drugs so it might seem sensible to use precious funding this way; Western donors may want to see epidemics contained quickly to avoid global spread; pictures of small African children dying of AIDS are more heartrending than a middle-aged man with hypertension, even if that man is supporting a large family; there is a myth that chronic diseases are more costly to prevent than infectious ones. This last issue is one that should be tackled strongly to spread awareness that low-cost methods can have an enormous effect on chronic diseases.

Vaccination for infectious diseases is a vital method of prophylaxis, and has transformed modern medicine. By contrast, research into vaccines against chronic diseases has been less successful, in part because of the increased complexity involved.

In this opinion piece, the authors outline the prospects for the development of chronic disease vaccines. These might not need to rely on the traditional method of inducing the body to produce antibodies, but rather on introducing monoclonal antibodies against specific proteins — this has so far worked well against Crohn's disease and rheumatoid arthritis.

The authors outline key hurdles in developing a successful therapeutic vaccine. Safety and efficacy are two obvious ones, but there is a third that is unique to vaccines for chronic diseases. Because these vaccines would block bodily chemicals — such as cytokines or hormones — it would not be acceptable for a vaccine to induce a life-long block (unlike a malaria vaccine, for example, where a lifelong block would be ideal).

These might be particularly useful in developing countries, say the authors. Because prophylaxis with vaccines is already a familiar concept, there should be no problem with patients' compliance, and judicious partnerships between public and private organisations could mean the vaccines are produced cheaply.

A mix of factsheets, opinion pieces and case studies on antibiotic resistance in developed and developing countries, the publication looks at the history of antibiotics, the development of resistance and possible ways of combating it. Some of the pieces look at how medical staff cope with resistance, particularly MRSA, in hospitals. The editorial emphasises the need for consumers to play their part, and urges people not to take the benefits of antibiotics for granted. The issue of antimicrobials in animals is covered because of growing evidence that resistant bacteria can spread from animals to humans.

This background piece to understanding antibiotic resistance in Africa is written in accessible language. It outlines the scale of the problem in Africa (bacterial infections cause 45 per cent of deaths) and the commonest types of infections — tuberculosis, respiratory illnesses and sexually transmitted infections.

It addresses problems of antibiotic resistance specific to African populations: the heavy burden of community-acquired infections; the limited range of first-line antibiotics and varying availability of second-line drugs (often vital against resistant bacteria); the hidden costs from longer hospital admission times and more expensive drugs needed to treat resistant pathogens.

The AIDS epidemic is linked to the problem – the HIV virus weakens people’s immune systems making them more susceptible to bacterial infection. In addition, antibiotics used prophylactically in AIDS patients to prevent opportunistic infections are also used for a wide range of bacterial infections, making it more likely that the pathogens will develop resistance.

Another problem is the sale of antibiotics by unsanctioned providers, who might give incorrect information about how to take the drugs. They frequently sell poor-quality or even counterfeit drugs that don’t cure the patient but encourage bacterial resistance.

Consumers need to be made aware of their own responsibilities, says the article, but ultimate responsibility lies with the healthcare providers in instituting and maintaining treatment programmes.

The factsheet outlines the problem of antibiotic resistance detailing the causes, consequences and factors that encourage the spread of resistance. It is ideal for people wanting a snapshot of the problem from WHO's perspective, although for more detailed information see the WHO global strategy for containment of antimicrobial resistance.

This Compilation lists the human subjects research legislation, regulations or guidelines for 79 countries, the European Union and the Commonwealth of Independent States, and several international organisations. It was developed for IRBs/Ethics Committees, researchers, funding agencies and others involved in international research with the aim of helping these groups familiarise themselves with the laws, regulations and guidelines of countries in which research will be conducted. A description of the methods used to collect and update the information is included.

This special issue is a large collection of opinion pieces, research and review articles, and news features that highlight the advances in knowledge and challenges to the treatment and prevention of HIV/AIDS, including articles on randomised trials of promising HIV drugs.

It also includes a look at the preventive potential of microbicides and prophylactic HIV drugs. Another key issue covered is the patients' right to access to HIV treatment, and the barriers to treatment that people face if they are migrants or from socially excluded groups such as injecting drug users.

One weapon that those fighting HIV long for is an effective vaccine, and researchers outline the scientific and policy challenges of developing an HIV vaccine. The issue of paediatric HIV/AIDS cases is also discussed.

This timeline details reported cases of bird flu in both animals and people from the first recording of the virus in China's Guangdong Province in 1996 onwards.

The document also highlights milestones in bird flu research, such as the October 2005 finding that the deadly 1918 pandemic virus shares characteristics with the H5N1 virus, and the March 2006 research that explains why H5N1 does not yet easily infect people.

The timeline also shows the geographical spread of the virus from Asia — especially South-East Asia — through central Asia, Europe, the Middle East, and Africa. The timeline is periodically updated — check the World Health Organization's avian influenza website for the latest version.

This paper maps African countries' knowledge base through patent applications and publications. It shows South Africa as academically, and technically, the strongest country of the continent. The number of publications is growing in other African countries, but patenting remains limited all-round.

The paper ends on a positive note, arguing that African countries already possess the basis for knowledge-driven development.

This collection of nine research articles, published by the Indian Academy of Sciences, presents the latest findings of a network of studies conducted by leading scientific institutes and researchers in India. They examine the likely national impact of climate change on issues such as water availability, tropical cyclone frequency, changes in forest type and malaria transmission rates. The collection also includes an analysis of current and predicted trends for greenhouse gas emissions from India, as well as commentary on mitigation strategies for ensuring sustainable development.

This set of questions and answers, prepared by the US Centers for Disease Control and Prevention (CDC), focuses on the threat that bird flu poses to public health. It also covers the spread of avian influenza in birds and other animals. The questions cover symptoms of infected birds and humans, and how to protect people against infection. They also outline factors that could trigger an influenza pandemic, and the measures needed to prepare for it.