Malaria Socio-Economic Issues

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QUESTION

What are the socio-economic issues on the spread of malaria?

ANSWER

Malaria transmission requires the presence of Anopheles mosquitoes; as such, conditions which favor the growth and persistence of these mosquitoes will also be hotspots for malaria transmission, provided the climate is also sufficiently warm for the development of the parasite within the mosquito.

Rural areas without sophisticated water and sanitation systems often utilize streams or ponds for everyday water needs; if these produce stagnant patches of water, they can be an ideal location for the development of mosquito larvae.

Similarly, if rural farmers dig canals or ditches to irrigate their fields, these can become breeding areas. Urban areas tend to have less standing water, apart from cisterns, so in many cases transmission is less prevalent in urbanized locations.

As a further socio-economic factor, preventing mosquitoes from entering the house and biting people is  key way to prevent infection. Rich people in malarial areas may be more able to have fully screened houses, possibly even with air-conditioning, which will prevent mosquitoes from establishing in the house. They may also be more likely to have access to a long-lasting insecticide treated bednet, which further reduces mosquito bites, and also access to accurate diagnostic screening and treatment, if they do happen to get infected.

All of these factors contribute to making malaria burden highest in some of the world’s poorest areas, with the highest levels of mortality in sub-Saharan Africa.

Socio-Economic and Environmental Conditions Contributing to Malaria

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QUESTION

what socio-economic and environmental conditions contribute to the disease?

ANSWER

Malaria transmission requires the presence of Anopheles mosquitoes; as such, conditions which favor the growth and persistence of these mosquitoes will also be hotspots for malaria transmission, provided the climate is also sufficiently warm for the development of the parasite within the mosquito.

Rural areas without sophisticated water and sanitation systems often utilize streams or ponds for everyday water needs; if these produce stagnant patches of water, they can be an ideal location for the development of mosquito larvae. Similarly, if rural farmers dig canals or ditches to irrigate their fields, these can become breeding areas. Urban areas tend to have less standing water, apart from cisterns, so in many cases transmission is less prevalent in urbanized locations. As a further socio-economic factor, preventing mosquitoes from entering the house and biting people is  key way to prevent infection. Rich people in malarial areas may be more able to have fully screened houses, possibly even with air-conditioning, which will prevent mosquitoes from establishing in the house. They may also be more likely to have access to a long-lasting insecticide treated bednet, which further reduces mosquito bites, and also access to accurate diagnostic screening and treatment, if they do happen to get infected.

All of these factors contribute to making malaria burden highest in some of the world’s poorest areas, with the highest levels of mortality in sub-Saharan Africa.

How Many Affected by Malaria

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QUESTION

About how many people in the world are affected, die and survive malaria?

ANSWER

It has been estimated that about 3.3 billion people, or close to half the world’s population, is at risk of malaria infection at least at some point during the year. However, preventative measures mean that many fewer actually contract malaria in a given year—still, there are an estimated 216 million cases of malaria every year; of these, about 655,000 patients die. Most of these in children under the age of five, and most in sub-Saharan Africa.

Malaria Deaths

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QUESTION 

what percent of people die each year from Malaria?

ANSWER

There are an estimated 216 million cases of malaria each year around the world, and about 655,000 deaths due to malaria. This means that overall mortality from malaria is actually very low, around 0.3%, of those who get infected. However, the majority of the people who die from malaria each year are children, and in sub-Saharan Africa.

In terms of the proportion of global deaths that are caused by malaria each year, the percentage is also very small—only about 1%. But that is still a lot compared to most other diseases, and malaria is still one of the leading causes of death of children under 5 in many parts of the tropics, and especially in Africa.

Malaria Deaths by Country

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QUESTION

Where are the most deaths of malaria?

ANSWER

Over 90% of the deaths from malaria occur in sub-Saharan Africa, and in children under the age of five. According to the World Health Organisation’s 2011 World Malaria Report, the countries with the five highest numbers of reported malaria deaths for 2010 are (and number of reported deaths): Kenya (26,017 deaths), Democratic Republic of Congo (23,476), Tanzania (15,867), Burkina Faso (9,024) and Uganda (8,431).

However, it is important to note that this indicates the number of reported deaths that were confirmed as malaria; there are other countries in Africa which may have similar levels of malaria mortality but insufficient health infrastructure for accurate diagnosis of cause of death or reporting. Even in countries where reporting levels are high, causes of death are not always accurately determined.

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.

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. Currently, the greatest burden of the disease is felt in sub-Saharan Africa, where over 90% of deaths due to malaria occur. The map below shows the estimated risk for malaria across the world, courtesy of the World Health Organisation.

Global_Malaria_2010_WHO

Map of the global distribution of malaria, courtesy of WHO (www.who.org)

Community Control of Malaria

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QUESTION

how can the community can control malaria through personal protection?

ANSWER

That’s a very good question. One of the most effective known ways for reducing infection with malaria is through the use of long-lastong insecticide treated bednets. Sleeping underneath one at night drastically reduces the chance of being bitten by the Anopheles mosquitoes that transmit malaria.

Other personal protection measures include indoor residual spraying (IRS) with insecticides, which reduces the number of mosquitoes inside houses and also prevents infection. These protection methods protect individuals and families from malaria, but they also can assist in interrupting transmission—that is, if enough families use bednets and do IRS, the whole community may benefit from reduced numbers of mosquitoes that are carrying malaria.

Estimates of the level of bednet or IRS coverage required for community benefits to occur vary based on the region and the local strength of transmission (Killeen et al. reported coverage ranging from 35%-65% as adequate for detecting community-level benefits. This was published in the journal PLoS Medicine in 2007). However, most organisations are advocating attempting 80% coverage of bednet use—therefore, large efforts are being made to increase current bednet coverage and IRS efforts, especially in sub-Saharan Africa where the highest number of cases and the highest mortality rates are observed.

How Many People Have Died from Malaria?

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QUESTION

How many people have died from this disease today? (2011)

ANSWER

Estimates for the number of annual deaths from malaria vary, and are not very accurate since they depend heavily on the quality of reporting. Since the majority of people who die from malaria are in sub-Saharan Africa, and often far from decent health facilities, it can sometimes be difficult to determine whether someone died of malaria or some other cause. The latest data available are for 2010 (2011’s statistics will be published some time in 2012): World Health Organisation estimated that last year approximately 655,000 people died from malaria, which was a decrease of 39,000 from 2009 and a drop of 25% from 2000. It is expected that the number of deaths will continue to fall in 2011. Organisations such as Malaria No More are dedicated to ending all deaths from malaria by the year 2015.

If you have ever taken anti-malaria medication, please take Malaria.com’s brief Malaria Medication Side-effects Survey: Treatment and Prophylaxis.