World Malaria Day Date

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QUESTION

What is the background of 25 April to be celebrated as World Malaria Day? Why just 25 April?

ANSWER

World Malaria Day was instituted by the World Health Assembly at its 60th meeting in May 2007. As far as I know, the choice of April 25th was arbitrary – it was almost a full year after the instituting assembly meeting, perhaps intending to give the organizers plenty of time to make preparations for the first observance of the day. In any case, World Malaria Day is now a symbolic date and a rallying time point for malaria advocacy and control efforts.

Malaria in Kitwe Zambia

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QUESTION

Is it dangerous for my children two years old in Kitwe?

ANSWER

Kitwe has been part of the Roll Back Malaria campaign to control malaria in Zambia—the program has been very successful, reducing deaths by malaria by over 65% nationwide. However, there still is a risk of contracting malaria in most parts of the country, and so preventative measures should be taken when visiting or living in Kitwe, such as sleeping under a long-lasting insecticide treated bednet, wearing long-sleeved clothing in the evening and at night and screening doors and windows to prevent mosquitoes from entering.

Malaria in the United States, Years Later

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QUESTION

For years, I have questioned what sickness I got years ago after a series of bug bites in a bayou in New Orleans. I’ve just read the symptoms described here and they fit everything I was suffering with. I even had problems with my liver, but I was never tested for Malaria because I had immediately left New Orleans for Italy. I never thought of mentioning it. This mysterious illness cropped up in different forms over the years and really I was never the same after it. It has been almost 12 years, and I still suffer from recurring illness which antibiotics help for a while, but it always comes back. Could it be that I have had Malaria in my system all this time?

ANSWER

While malaria was officially eradicated from the US in the 1950s, certainly the swamps and bayous of Louisiana and the rest of the Gulf were a key habitat and a major source of transmission prior to eradication. I just found a news report in the New York Times from October 1883 which reported 16 deaths due to “malarial fever” in the previous week alone!

While these days, virtually all of the 1,500 or so cases of malaria observed in the US every year are attributed to overseas travel, in 2002 a handful of cases of malaria in northern Virginia were believed to be due to local transmission. Prompt treatment, personal protective measures (such as screening houses) and vector control quickly quelled that mini-outbreak.

Given this history along with your symptoms, and particularly your recurrent episodes of fever, I would not rule out malaria, obtained in Louisiana, as a possibility! You should talk to your doctor about the possibility of a serological test for the antibodies against malaria—if positive, you should try to have a blood test done next time you have the recurrence of symptoms. If malaria is confirmed, you should report your case to the Centers for Disease Control (CDC) Domestic Malaria Unit, which monitors all malaria cases in the US.

Malaria Beliefs

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QUESTION

How do beliefs and attitude affect the spread, treatment and prevention of malaria?

ANSWER

Accurate information and knowledge about how malaria is transmitted, diagnosed and treated is crucial to controlling the disease, for the general public living in malarial areas, travelers to these areas and health professionals. For example, many travelers are unaware that their destination is in a malaria transmission zone, so they do not take appropriate preventive precautions. Similarly, many travelers I have met believe that if they have had malaria once, they are immune and cannot get reinfected, so don’t bother protecting themselves from mosquitoes – this is not true, and they are inadvertently putting themselves at great risk.

In terms of endemic areas, the focus is on educating people about day-to-day preventive measures, such as sleeping under long-lasting insecticide treated bednets and indoor residual spraying. Educational campaigns that focus on simple, straightforward ways to prevent malaria are more likely to influence people’s attitudes and lead to better malaria control. Similarly, teaching people to seek accurate diagnosis and then ensuring they have appropriate treatment is an important step.

In some places, people feel they cannot afford to visit a doctor or clinic, or would rather place their trust in a traditional healer or healing herbs; since the most effective medications against malaria are treatments such as artemisinin-based combination therapies, which are available through official health sources such as clinics, believing in traditional medicine can lead to the malaria infection becoming very severe, and even resulting in death. As such, another component to control is making sure that medical services such as clinics are easily accessible even for the poorest people, provide good health care and are affordable.

Prevention of Malaria

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QUESTION

What is the prevention of malaria?

ANSWER

Malaria prevention consists of a combination of mosquito avoidance measures and chemoprophylaxis. Although very efficacious, none of the recommended interventions are 100% effective.

Mosquito Avoidance Measures

  • Because of the nocturnal feeding habits of Anopheles mosquitoes, malaria transmission occurs primarily between dusk and dawn.
  • Contact with mosquitoes can be reduced by remaining in well-screened areas, using mosquito bed nets (preferably insecticide-treated nets), using a pyrethroid-containing flying-insect spray in living and sleeping areas during evening and nighttime hours, and wearing clothes that cover most of the body.
  • All travelers should use an effective mosquito repellent.
  • The most effective repellent against a wide range of vectors is DEET (N,N-diethylmetatoluamide), an ingredient in many commercially available insect repellents. The actual concentration of DEET varies widely among repellents. DEET formulations as high as 50% are recommended for both adults and children older than 2 months of age (see the Protection Against Mosquitoes, Ticks, and Other Insects and Arthropods section later in this chapter). DEET should be applied to the exposed parts of the skin when mosquitoes are likely to be present.
  • In addition to using a topical insect repellent, a permethrin-containing product may be applied to bed nets and clothing for additional protection against mosquitoes.

Read the full article about Malaria Prevention.

What does the goverment do to help malaria?

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QUESTION

Does the goverment help malaria?

ANSWER

Many governments around the world assist in controlling malaria. Some countries, like Australia and the United States, used to have malaria transmission occur within their own borders, but through dedicated control programs, have managed to eradicate the disease locally. In these cases, the government coordinated huge programs of draining standing water, spraying insecticides and ensuring that health clinics were equipped to diagnose and quickly treat any human cases.

Nowadays, the governments of the US and Australia, along with many other countries which do not have malaria, still assist in the fight against malaria by funding malaria control programs in other countries, either directly (for example, the US funds international health projects through the US Agency for International Development) or indirectly, through international organisations like the World Health Organisation and the Global Fund for HIV, TB and Malaria. They also provide training in technical expertise to scientists, doctors and clinicians from malaria-endemic countries.

The governments of countries which have malaria are also deeply engaged in fighting the disease, mostly through their respective Ministries of Health, which often have specific malaria departments. In India, for example, malaria control is carried out by the National Vector Borne Disease Control Programme (NVBDCP), which is part of the Directorate General of Health Services. The NVBDCP carries out a multi-pronged strategy to combat malaria, including early case detection and treatment, vector control (with spraying, biological control and personal protection), community participation, etc. In Uganda, the Malaria Control Programme also carries out the above activities, and also provides intermittent preventative treatment against malaria for young children and pregnant women and has in the past engaged in large-scale distribution of long-lasting insecticide treated bednets. Both countries also explicitly include monitoring and evaluation as part of their control strategies, to make sure that any interventions or control efforts they make are having a positive impact on reducing malaria morbidity and mortality.

Geographic Range of Malaria

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QUESTION

Has the geographic range of malaria increased over the past 20 – 30 years? I have read that preventative measures have helped lower rates of infection, but I’m interested in the extension of the range itself.

ANSWER

That is a very interesting question, and one that garners quite a lot of debate. Preventative measures have actually also helped to limit the range of malaria globally. For example, malaria used to be relatively common in the Mediterranean basin and south-eastern United States, but control measures (mainly based around killing mosquitoes and removing suitable mosquito habitat) has largely eradicated malaria from these areas.

However, there is concern that on-going and future climate change has and will change the  distribution of malaria globally. For example, some predictions have suggested that malaria might be able to re-establish itself in the Mediterranean and Middle East, due to higher rainfall and higher winter minimums of temperature. Additionally, malaria may be able to spread to higher altitudes in areas where it is already present at low elevations. This is of huge concern in places like Kenya: Nairobi, the capital city (with around 5million people), sits at 1660 m altitude, and as such currently has generally negligible levels of malaria transmission. However, if climate change enables malaria to move up to this altitude, a huge number of people will be at additional risk of infection. Worryingly, there is some evidence from the Kenyan highlands that these changes are already underway.

Having said this, there are also parts of the world which might see malaria transmission ease as a result of climate change. This is particularly the case where rainfall is expected to decrease, or change significantly in relation to temperature. Moreover, some scientists think that on-going control efforts, particularly with respect to the distribution of bednets, vector control and greater coverage of diagnosis and treatment will continue to reduce the geographical spread of malaria over and beyond the changes associated with climate change. These scientists have compiled a map of Plasmodium falciparum transmission now as compared to data from before control interventions were rolled out—the reduction of transmission risk in many parts of the world, are clear to see (see below).

changing plasmodium falciparum map

Maps showing changes in transmission risk and endemicity of Plasmodium falciparum malaria between approximately 1900 (a) and now (b). (c) shows the balance of change in malaria transmission between the two time periods: the higher the negative number, the greater the reduction in malaria transmission. A positive number indicates increased malaria transmission. The different classes of malaria transmission risk are as follows: hypoendemic, prevalence < 10%; mesoendemic, PR ≥ 10% and < 50%; hyperendemic, prevalence ≥ 50% and < 75%; holoendemic, prevalence ≥ 75%. Image reproduced here from Gething et al., (2010), 'Climate change and the global malaria recession', in Nature, volume 465, pages 342-345.

Malaria in KwaZulu Natal

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QUESTION

How many people are infected by malaria in KZN?

ANSWER

By “KNZ” I assume you mean KwaZulu Natal (for the benefit of other readers, this is a region of South Africa, in the north-eastern portion of the country). KZN is one of the few parts of South Africa that experiences malaria transmission, though effective control measures have reduced its impact as a public health threat.

Up until 1996, South African policy had been to use DDT (even though it was a banned substance) to control mosquito populations, and malaria levels had correspondingly been low. However, after cessation of spraying with DDT, the number of malaria cases increased, to a high of over 40,000 cases in the 1999/2000 malaria season (in KZN, malaria is most commonly transmitted during the wet summer months, from November to May). Since then, the use of DDT as an insecticide has been reintroduced (along with other public health measures, such as switching to artemisinin-based combination therapies for first-line malaria treatment), and the burden of malaria has plummeted.

The most recent data I could find reported less than 3500 cases for the 2001/2002 malaria season, and zero cases in 2002/2003 (though the data I found were only up to February 2003). Efforts to coordinate malaria control between South Africa, Mozambique and Swaziland have also contributed to the success of reducing malaria transmission in the region.

Malaria Vaccine Research

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QUESTION

Is there any research to produce anti malaria vaccine, if not, why?

ANSWER

There are many teams of scientists working hard to try to produce a malaria vaccine. In fact, only last year, the preliminary results of a vaccine trial were published. The vaccine, called RTS,S, has been produced by GlaxoSmithKline and is in the midst of Phase III trials in Africa. The preliminary results showed approximately a 50% reduction in malaria incidence, though it is not clear how much of that protection came from the vaccine and how much should be attributed to the vaccine adjunct (a compound given with the vaccine to boost immune responses).

The preliminary results also did not include analysis of how much the vaccine prevented mortality due to malaria, and levels of protection against severe malaria appeared to be low. However, we will have to wait until 2014 for the full and final results of the clinical trial to be made available. In the meantime, other vaccine candidates are being developed, but there are many challenges to overcome.

For example, there are five different types of malaria that infect people: these differ significantly in the way they develop in the human host, and so a vaccine appropriate for one may not be effective against the others. Most vaccine researchers are focusing on Plasmodium falciparum, the most deadly form of malaria, and a vaccine effective against this parasite would certainly do the most to reduce malaria-related mortality. However, Plasmodium vivax also causes high morbidity, particularly in Asia and the Pacific, and so should not be overlooked.

Moreover, within each of these species exist different strains in different areas, each of which can be markedly different from a genetic perspective. Finally, we do not yet fully understand the complex ways in which our immune system reacts to malaria. As such, this presents a challenge to developing an effective malaria vaccine, though many scientists are willing to address this challenge and have made big inroads in the search for a safe, effective vaccine. For more information on current efforts to develop a malaria vaccine, please see PATH’s Malaria Vaccine Initiative.

Malaria Transmission and Deaths in the United States

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QUESTION

How do you get malaria? How does malaria come to the United States? How many people have died from malaria?

ANSWER

Malaria is caused by infection with single-celled parasites called Plasmodium. There are five different species which infect humans; of these, Plasmodium falciparum is the most deadly. The Plasmodium parasites are transmitted to humans through the bite of an infected female Anopheles mosquito; when these mosquitoes bite a human, they transfer some of the parasites in their saliva.

After undergoing one set of multiplications in the liver, the malaria parasites are released into the blood, where they repeatedly infect and destroy red blood cells, multiplying in the process. These cycles of infection and destruction of red blood cells cause the cyclical fever that is characteristic of malaria. Eventually, the parasite produces new types of cells, called gametocytes; if the patient is then bitten by another mosquito, the mosquito can take up gametocytes as well as blood when it feeds, and the cycle continues.

Malaria used to be relatively common in the United States, though usually only occurring during the summer months and restricted to the warm, wet south-eastern region. However, a concerted control campaign in the 1940s, focusing mainly on vector control (i.e. killing mosquito and reducing their opportunities for breeding) swiftly led to the eradication of malaria from the US.

Nowadays, virtually all malaria cases in the US are imported from abroad, whereby people get infected when traveling to other countries, but are only diagnosed as having malaria when they return home. There are about 1,000 cases of malaria reported each year in the US, and most of these were actually caught outside the US. Very rarely, an Anopheles mosquito will bite one of these travelers once they have returned from abroad, and therefore have the potential to transmit malaria within the US. However, due to a strong public health network and good access to malaria diagnosis and treatment, these events rarely lead to more than a handful of cases before they are quickly treated and transmission eliminated again.

The World Health Organisation estimates that last year, approximately 700,000 people died of malaria. Of these, 90% were in sub-Saharan Africa, and the vast majority were children under the age of 5.