Duration of Malaria Symptoms

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QUESTION

If untreated how long will a person suffer symptoms caused by Malaria?

ANSWER

The answer to that depends a lot on what type of malaria they have as well as their own immune status, and particularly if they have been infected with malaria before. So, for example, P. falciparum is the most severe and deadly kind of malaria, and without treatment, many people who do not have acquired immunity (from previous infections) are likely to die within just a few days. This is the type of malaria that causes the most deaths, and explains why most of the fatalities occur in young children, who have not had the chance to acquire immunity.

In contrast, other kinds of malaria are less severe, and so symptoms can persist before the malaria parasite is naturally cleared by the parasite, usually within 1-2 weeks. In extreme cases, this can last much longer; Plasmodium malariae is the slowest replicating form of malaria, and so frequently causes mild infections which can last weeks, if not months. In some cases, people are infected with low levels of P. malariae for years without even experiencing symptoms, since their own immune system is able to keep levels of the parasite low enough so that they don’t cause noticeable disease.

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.

Which Malaria is Most Deadly

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QUESTION

In which form of malaria is the death rate highest?

ANSWER

The most dangerous form of malaria in people is Plasmodium falciparum. It causes the most severe symptoms (for example, “cerebral malaria”) and also the most deaths. It is widespread around the world, but most deaths due to P. falciparum (and in fact, all malaria) occur in sub-Saharan Africa.

Malaria in Africa

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QUESTION

How many in Africa have been affected by Malaria?

ANSWER

In 2010, there were approximately 174 million cases of malaria in Africa. However, some people may present with more than one case of malaria per year (especially young children), so the number of people affected is likely considerably lower. However, 90% of deaths from malaria occur in Africa, and 60% in just six countries: Nigeria, DR Congo, Burkina Faso, Mozambique, Cote d’Ivoire and Mali. The good news is that malaria mortality has dropped by 33% in Africa since 2000, which is a very encouraging trend, though the aim of organizations such as Malaria No More is to fully eliminate deaths from malaria globally by 2015.

Malaria Vaccine

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QUESTION

Is there a vaccine for malaria?

ANSWER

No, as of yet there is not a vaccine available for malaria. The most promising vaccine candidate, RTS,S, which has been developed by GlaxoSmithKline, is currently undergoing Phase III trials in Africa. The trial is not due to finish until 2014, so we will have to wait until then to know how effective it is. Preliminary results, published last year, suggested that it may prevent up to 50% of malaria cases in young children, though the long term protection level is not known. Other age groups will also have to be analyzed, as well as the effect of the vaccine on malaria mortality levels.

Malaria in Limpopo, South Africa

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QUESTION

In which year did malaria spread in Limpopo?

ANSWER

Malaria has likely been in the southern part of Africa for many hundreds, if not thousands, of years. In recent times, control initiatives have been in place in areas of malaria transmission in South Africa since 1945, reducing the incidence of malaria in many places. Other than that, this paper, freely accessible via the Malaria Journal, reports on the incidence, number of cases and number of deaths reported as caused by malaria between 1998 and 2007: Gerritsen et al., 2008. In addition, this site, by the South African government in Limpopo, contains more information about malaria in the area: Limpopo Malaria Control Program.

Where Does Malaria Occur?

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QUESTION

Where does malaria occur?

ANSWER

Malaria has at some stage or another occurred on every continent of the world except Antarctica. Currently, cases of human malaria are mainly found in Central and South America, parts of the Caribbean, sub-Saharan Africa, parts of the Middle East, south Asia, south-east Asia, and the Pacific Islands of Oceania. Control efforts, mainly consisting of reducing populations of vector mosquitoes, has eliminated transmission from North America, most of Europe, most of North Africa and parts of the Middle east and Asia. Currently, the vast majority of malaria mortalities occur in sub-Saharan Africa, and mainly in children under the age of five.

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.

Vaccine for malaria? Differences with yellow fever?

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QUESTION

Is there a vaccine to prevent malaria?
What is the difference between yellow fever and malaria?

ANSWER

In answer to your first question, no, there is not currently a vaccine available to prevent malaria. The best current candidate, the RTS,S vaccine which was developed by GlaxoSmithKline, is currently undergoing Phase III clinical trials in Africa. Although preliminary results showed up to a 50% rate of protection against malaria in some age groups, the trials will not conclude until 2014 and so full results will not be known until after that date.

As for your second question, while yellow fever and malaria are both transmitted by mosquitoes, they share few other similarities. Yellow fever is caused by a virus, for example, whereas malaria is caused by a single-celled parasite of the genus Plasmodium. The group of organisms that Plasmodium belongs to is often called “Protista” (the exact grouping and classification constantly changes!), and they more generally belong, based on cell type, to the Eukaryotes, an enormous group of organisms which also includes all mammals and even humans! Viruses, on the other hand, are tiny pieces of genetic material wrapped in a protein coating, and can hardly be described as alive in a conventional sense.

While both yellow fever and malaria are transmitted by mosquitoes, yellow fever is transmitted by the genus Aedes, whereas malaria is exclusively transmitted by the genus Anopheles (at least in humans, and all other mammals for that matter).While spraying inside households may reduce the prevalence of  both types of mosquitoes, Aedes mosquitoes tend to feed during the day, so sleeping under an insecticide-treated bednet is less protective against yellow fever than it is against malaria. Also, a vaccine is available for yellow fever (and has been available for over 50 years), whereas as I describe above, no such vaccine yet exists for malaria.

Finally, while superficially the symptoms of yellow fever and malaria may seem similar (fever, nausea, aches), other manifestations of the disease can be very different. Yellow fever is technically considered a hemorrhagic disease, since it can cause increased tendency to bleed in patients. Also, in some patients, the initial symptoms are followed by an acute liver phase, causing jaundice which can turn the patient yellow (and hence the name). Malaria can also affect the liver, and cause ild jaundice, but usually not to the extent of yellow fever.  Once a patient has been diagnosed with yellow fever, there is no specific treatment, and the patient is merely treated based on symptoms, to ease their discomfort. Vaccination is the mainstay of control of this disease, and has been very successful in many places; the total number of worldwide cases is estimated by the World Health Organization to be around 300,000, with 20,000 deaths, mainly in Africa.

The burden of malaria is also mainly felt in Africa, though the number of cases and deaths is vastly higher – globally, there are approximately 200 million cases of malaria in 2010, with almost 700,000 deaths. Along with the general symptoms of fever and nausea, the most dangerous manifestation of malaria is when it causes cerebral symptoms; this is usually only caused by Plasmodium falciparum malaria, and can lead to impaired consciousness, coma and even death. Also in contrast to yellow fever,  the mainstay of control is a combination of prevention (mostly with vector control, i.e. using bednets, indoor residual spraying and destruction of breeding habitats and larvae) and treatment (using a variety of medications).