Distribution of Malaria

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QUESTION

Where does malaria mostly take place?

ANSWER

Malaria is mainly transmitted in tropical regions of the world; while some transmission does occur outside of the tropics, it tends to be seasonal in these areas (i.e. usually only during periods of high temperature/high rainfall). Within the tropics, malaria is found on all continents, though the highest number of cases is in Africa, which is also where over 90% of deaths due to malaria occur (of these, most are children under the age of 5). Outside Africa, the next highest levels of malaria are in India and south-east Asia and the western Pacific (such as Papua New Guinea).

How Many Malaria Deaths in Africa?

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QUESTION

What is the estimated number of deaths in Africa caused by malaria each year?

ANSWER

The exact numbers of deaths caused by malaria every year is very difficult to measure accurately, due to difficulties in diagnosis and also failure to report cases. However, the Roll Back Malaria partnership, coordinated by a host of international organisations including the World Health Organisation, estimates that last year approximately 801,000 people died of malaria in Africa, which represents over 90% of the total annual worldwide deaths. Of those, the vast majority of victims were children under the age of five.

How many countries have malaria?

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QUESTION

How many countries are malaria infected?

ANSWER

As of 2010, there were 108 countries which were listed as having endemic malaria—that is, malaria which was transmitted within the country. This includes 43 countries in Africa, 10 countries in south-east Asia, 13 countries in the Eastern Mediterranean (which includes most of Central Asia and parts of North and East Africa—90% of the malaria burden in this region is suffered by Sudan, Afghanistan, Pakistan and Somalia), 10 countries in the Western Pacific (though this region constitutes less than 1% of global malaria cases) and 23 malaria-endemic countries in the Americas.

Malaria In Africa

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QUESTION

What factors cause Africans to get this disease?

ANSWER

The highest number of malaria cases every year occur in Africa, not because of anything specifically due to the people living there (in fact, they may be better protected against malaria than most—I will come onto this later) but because malaria transmission is very high in many parts of sub-Saharan Africa and sufficient preventative measures are still lacking in some places.

Malaria transmission requires specific environmental criteria, such as sufficient temperature and rainfall. These conditions are met in many countries in Africa, and unlike some other parts of the world, temperatures are suitable year-round for the development of the Anopheles mosquitoes that act as the vector for mosquito, meaning that in some places, transmission can occur throughout the year. In addition, many people do not take appropriate preventative measures against malaria; in some cases, this is due to a lack of means to buy items such as insecticide-treated bednets, and in other cases people have not been educated about the dangers of malaria or how to prevent it, so they do not know what preventative measures they should be undertaking.

Organisations such as the World Health Organisation, the US Agency for International Development, the Global Fund, the Roll Back Malaria consortium and Malaria No More are working to improve both access to preventative measures, such as bednets and indoor residual spraying, while also educating people about the need for prevention and also what to do if they suspect themselves or a family member has malaria. These efforts have already reduced the burden of malaria in Africa; the number of deaths is dropping every year, and they hope to have eliminated deaths from malaria altogether by the year 2015.

I mentioned that Africans may be better protected against malaria naturally—scientists have noted that populations living in areas with high levels of malaria have some genetic protection against infection. One example of this is the Duffy antigen. People who are negative for this gene seem to be protected against Plasmodium vivax and P. knowlesi malaria (it was originally thought they were resistant to infection, but more recent evidence from Kenya suggests in fact they still get infected, but do not get as sick). Another is the gene for sickle cell anaemia; despite causing highly debilitating and even lethal anaemia if both copies of the gene are inherited, a single copy of the gene confers strong resistance against malaria. Both of these genetic traits are highly prevalent in African populations.

In addition, early exposure to malaria results in the acquisition of immunity to infection. This, over time, Africans who survive childhood malaria go on to be less susceptible as adults. The exception to this are pregnant women; in order to support the growing foetus, a pregnant women’s immune system becomes much weaker (otherwise there is a risk of the immune system rejecting the foetus). As such, even if she had high levels of acquired immunity to malaria prior to her pregnancy, once pregnant she becomes much more susceptible. This is particularly true for a woman’s first pregnancy.

Mobile Phone Text Messaging: Tool for Malaria Control in Africa

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Across many malaria-endemic areas in rural Africa, the communication gap between managers, health workers, and patients is a significant barrier to efficient malaria control. The rapid expansion of mobile network coverage and the widespread availability of basic handsets have the potential to substantively bridge the communication gap. Text messaging, as the least-expensive mobile phone function found on all handsets, could improve the delivery of health services and health outcomes.

Six major areas of malaria control in which deficiencies are apparent and text messaging interventions could be beneficial are:

  1. Disease and treatment effectiveness surveillance
  2. Monitoring of the availability of health commodities
  3. Pharmacovigilance and post-marketing surveillance of the safety and quality of antimalarial drugs
  4. Health worker adherence to guidelines
  5. Patient adherence to medication regimen
  6. Post-treatment review

Text messages transmitting information from the periphery of the health systems to malaria control managers are in the first three malaria control areas: (1) disease and treatment effectiveness surveillance, (2) monitoring of the availability of health commodities, and (3) pharmacovigilance and post-marketing surveillance of the safety and quality of antimalarial medicines. Future projects in these three areas should demonstrate responses to data signals and comparative advantages with routine information systems.

Text messages in the second three areas transmit information to health workers and patients to support the management of malaria patients by improving (4) health workers’ adherence to guidelines, (5) patient adherence to medicines, and (6) post-treatment review. Future priorities in these areas are cost-effectiveness evaluations, qualitative research, and studies measuring impact on the processes of care and health outcomes.


Funding: DZ is supported by the Wellcome Trust project grant [#084253]. RWS is supported by the Wellcome Trust as Principal Research Fellow [#079080]. AOT is supported by the Worldwide Antimalarial Resistance Network (WWARN) through a Bill & Melinda Gates Foundation grant [#48807.01]. All authors acknowledge support from the Wellcome Trust core grant [#092654/Z/10/A]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

Citation: Zurovac D, Talisuna AO, Snow RW (2012) Mobile Phone Text Messaging: Tool for Malaria Control in Africa. PLoS Med 9(2): e1001176. doi:10.1371/journal.pmed.1001176

Copyright: © 2012 Zurovac et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Full Article: Mobile Phone Text Messaging: Tool for Malaria Control in Africa (PDF)

 

Malaria in Africa

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QUESTION

What is the current problem for malaria in Africa?

ANSWER

Malaria is a particularly severe problem in Africa due to a number of reasons. First of all, transmission in many parts of Africa occurs year round, due to favourable conditions for the development of the mosquitoes malaria requires as its vector.

Secondly, the dominant and most widespread species of malaria in Africa is Plasmodium falciparum, which is most fast-acting and deadly form of the disease.

Thirdly, Africa has a very young population; birth rates are high across much of the continent, and in many countries, more than 40% of the population is under 15 years old. Given that young children are are higher risk of malaria than adults, this also increases the burden of malaria in Africa compared to other parts of the world.

Finally, access to health care and malaria control interventions in Africa has been plagued by more general issues of slow development. While national health systems are slowly emerging, many countries are still reliant on foreign aid and NGOs to provide even basic health services.

Even where these organisations can provide health care, they often face challenges such as reaching remote populations without good road access, finding ways to provide medical services without reliable electricity or communications networks and maintaining supply chains of diagnostic tools and crucial medicine.

However, signs of progress are being seen. Long-lasting insecticide treated bednets have been put forward as a key preventative measure against malaria, and to date millions have been distributed to people living in malarial areas in Africa, and particularly to high risk groups such as young children and pregnant women.

Simultaneously, other control initiatives, such as indoor residual spraying, are gaining traction and being deployed in more areas. An emphasis on local capacity building has encouraged community involvement in drug distribution and access to health care initiatives, as well as training local health workers in diagnostic methods in rural areas.

Encouraging reports from groups such as Malaria No More and the Roll Back Malaria consortium suggest that the number of deaths from malaria in Africa last year was the lowest in history, and efforts are underway to reduce that number to zero, worldwide, by the year 2015.

Where did malaria start in Africa?

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QUESTION

Where did malaria start in Africa?

ANSWER

Malaria has been present in Africa for tens of thousands of years; given this ancient history, it is very difficult to know exactly where it first entered the continent. Also, there are several different types of malaria in Africa, which have likely had different histories, and malaria researchers continually unearth new evidence regarding the origins of these different species.

For example, it has long been thought that Plasmodium falciparum, the most deadly form of malaria, emerged somewhere in the western Congo Basin in Central Africa. Originally, it was thought to have crossed over into humans from a closely related species found in chimpanzees, but recent research, published only in 2010, has suggested that a new species, found in gorillas, is actually the closer relative.

Plasmodium vivax, the most geographically widespread species of malaria that infects humans, has less clear origins. Many of its closely related species occur in south-east Asia, which leads some researchers to suggest this is where it emerged, passing into Africa as humans and their livestock moved across Asia towards the Middle East and North Africa, or possibly via  migration through Madagascar. However, other researchers argue that the high prevalence of certain genetic mutations which protect against Plasmodium vivax malaria found in populations in Africa and of African descent, and particularly West Africa, is evidence that P. vivax actually originated on this continent.

Malaria in Africa

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QUESTION

What percent of Africa has malaria?

ANSWER

That is very difficult to measure, but maps of malaria transmission potential show that malaria is potentially present across most of the continent, excluding the heart of the Sahara and Kalahari deserts, and the highlands of Ethiopia, Lesotho and Uganda/Rwanda. Other parts of the continent, such as the coastline of North Africa (along the Mediterranean) and much of South Africa and Zimbabwe likely only experiences seasonal transmission of malaria, with some parts of the year too cold and/or dry to support transmission. The below map shows the distribution of malaria throughout Africa, and should give you some idea of the percentage landcover that is affected.

Distribution of endemic malaria

Distribution of endemic malaria in Africa. Picture courtesy of http://siteresources.worldbank.org/NEWS/Images/malaria-map.jpg

Where is Malaria Found?

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QUESTION

Where is malaria found?

ANSWER

Malaria is found throughout the world’s tropical and sub-tropical areas, and mainly in Central and South America, Africa, Asia and the Indo-Pacific region. It is most common in tropical regions, where transmission occurs year-round; in sub-tropical and temperate areas, transmission may only occur during seasons that have appropriate climatic conditions. This includes sufficiently high temperature and water availability for the growth and development of the mosquito, which transmits the disease. The map below shows the estimated risk for malaria across the world, courtesy of the World Health Organisation.

To search an up-to-date malaria map by country, please visit the CDC Malaria Map application.

global malaria risk

Map of estimated malaria risk (2010 data). Courtesy of WHO (http://www.who.int/en/)

Repellent for Malaria Mosquitos

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QUESTION

My daughter is leaving for Africa for 5 weeks on a mission trip. Is there a repellent that can be used to ward off these infected mosquitos? Also what can she do to stay safe and protected?

ANSWER

There is no way of warding off only those mosquitoes that are infected with malaria. However, insect repellents which contain DEET (10% or higher) are the most effective against the species of Anopheles mosquito that carry malaria.

From personal experience, I can tell you that “natural” insect repellants that do not contain DEET are just not as effective against these mosquitoes. Your daughter can also spray her clothing with permethrin, which repells insects, and she should wear long-sleeved clothing in the evenings, early mornings and at night, when the malaria mosquitoes are most active. She should also try to sleep every night under a long-lasting insecticide treated bednet, which drastically reduces the number of bites.

In addition, your daughter should look into taking anti-malarial preventative medication, known as malaria prophylaxis. There are a number of different types; the two most commonly recommended for Africa are doxycycline (cheap, effective, but can cause sun sensitivity and so people taking it must be vigilant about using sun block! It also needs to be taken for four weeks after leaving the malarial area) and atovaquone-proguanil (sold as Malarone—this is effective, and has very few side effects, but is often very expensive. It only needs to be taken for a week after returning home), both of which are taken as a daily pill with food.