Supermalaria

Get any two mission workers from the Tropics together, and it’s only a short time before they start talking about malaria.  But now this is something we need to take even more seriously as evidence emerges of a ‘supermalaria’ which has developed resistance to the main drugs used for treating the illness.

We have blogged about malaria before, but this development needs to be brought to everyone’s attention.  In a letter to the British medical journal The Lancet a team of researcher from the Oxford Tropical Medicine Research Unit in Bangkok report what they call “a sinister development” and say that the new strain of malaria has

outcompeted the other resistant malaria parasites, and subsequently acquired resistance to piperaquine.

You can read the full text of their letter here.

Originating in Cambodia and currently spreading across south-east Asia, there is now a race against time to eliminate this problem before it spreads to major population centres.  The renewed risk is a timely reminder to mission workers, short-term teams and the people we work alongside to take malaria seriously.  While continuing to take the appropriate chemoprophylaxis recommended by medical advisors, but more attention needs to be given to avoiding being bitten in the first place – here are our top tips:

  • Make sure there is no standing water near your home, school or office for mosquitos to breed in. If you can’t eliminate standing water, pour a small amount of paraffin into it to break the surface tension and drown mosquito eggs.
  • Ensure there is no lawn within 100 metres of your home, school or office. Mosquitos feed on the grass sap so are attracted to green lawns.
  • Fit mosquito netting to windows and doors and check it regularly for damage.
  • Spray bedrooms with a pyrethoid-based spray before dusk.
  • Sleep with air conditioning or an electric fan as the cool and turbulence deters mosquitos.
  • Always sleep under an insecticide-impregnated mozzie net. Replace nets periodically and re-impregnate them every 6-12 months, depending on how frequently you wash them.
  • Cover up arms and legs with loose-fitting clothing, particularly if sitting outdoors in the evening.
  • Always use mozzie repellent spray on any remaining exposed skin – ones containing DEET are generally considered to be the most effective.
  • There is no evidence that insect electrocution devices or sonic repellants work, although many people continue to use them.
  • Eating raw garlic, chilli or Marmite are often believed to deter mosquitos although there is no evidence proving this!

And finally, take symptoms of malaria seriously, particularly if you’re in south-east Asia.  Many experienced mission workers shrug malaria off as if it is no worse than a case of flu, but this time it may be much harder to treat.

More bad news for malaria

mosquitoSix months ago we told you about the possibility of a vaccine against malaria, which is now awaiting regulatory approval.  Last week news emerged of another breakthrough discovery which could help prevent people dying from one of the world’s most dangerous diseases.

According to a research article in the journal Science, a team of scientists based in the United States has identified a group of Tanzanian children who have naturally-occurring resistance to malaria.  Normally hard for the human body to combat, malaria parasites enter into the human blood stream by way of a mosquito bite and then invade red blood cells where they multiply, before bursting out in great number, overwhelming the human immune system and heading for new cells.  Their success consists of spending much of their time inside human cells, so the immune system cannot identify them except for brief moments.

Red blood cells infected by malaria

Red blood cells infected by malaria

The children identified in Tanzania produced antibodies which stopped malaria parasites leaving infected red blood cells, thereby limiting their opportunity to continue reproducing before the infected cells are destroyed naturally in the spleen.  The research was confirmed by checking against a survey of 138 Kenyan men and adolescent boys with the antibodies who were found to have a significantly lower number of parasites than those without.

One of the lead researchers explained that “Most vaccine candidates for malaria have worked by trying to prevent parasites from entering red blood cells.  We’ve taken a different approach. We’ve found a way to block it from leaving the cell once it has entered. It can’t go anywhere. It can’t do any further damage.

We’re sort of trapping the parasite in the burning house.

Effective prevention

Effective prevention

The research was tested on laboratory mice which were given a transfusion of blood containing the antibodies, and then infected with malaria.  The result was to cut by nearly 75% the number of malaria parasites infecting the mice, and to double their survival rate.  If these results are reproduced in the next stage of the trials – using monkeys – it is hoped that a vaccine will be ready for trials on humans within 18 months.

If successful, this research could go a long way towards reducing the 600,000 deaths from malaria each year.  But, as we said in our previous blog which also covered preventive measures, the best way to avoid dying of malaria is to avoid being bitten by a mosquito!

Malaria

mosquito

An anopheles mosquito

A new malaria vaccine – the first in history – has passed its trials recently, so we thought it might be a good idea to bring you all up to speed on it.  Malaria is a significant global public health issue, claiming over 600,000 lives a year, mostly children in sub-Saharan Africa, so anything that can make a dent in those statistics is a welcome development.

The new vaccine, RTS,S (also known as Mosquirix)  is produced by GlaxoSmithKline, with $200m of funding from the Bill and Melinda Gates Foundation, and is the culmination of a sixty year search for the Holy Grail of tropical medicine.  Because malaria is such a varied disease, it is notoriously hard to fight, but RTS,S works by introducing one protein from the parasite into the human immune system so that it will respond more rapidly to an infection.  In Phase III trials in seven African countries in children and infants it was found to significantly reduce the incidence of malaria for up to 18 months.  You can read the GlaxoSmithKlein press release here.

Malaria zones (source: Rpyal Perth Hospital)

Malaria regions (source: Royal Perth Hospital)

GSK hope to get the vaccine to market by 2016, and plan to sell it at a price which will cover the cost of production plus 5%, with profits being ploughed back in to product development.  It remains to be seen, of course, whether the cost will be low enough to be affordable to many countries which desperately need it.

As well as this prophylactic, there are also well-established preventatives such as malarone, a relatively expensive but highly effective prophylactic , and doxycycline, a mild antibiotic noted for its lack of serious side effects other than reducing tolerance to sunlight, which makes it problematic in the tropics.  Many adult prophylactics are not recommended for children, particularly Lariam, which has been linked to vivid nightmares, anxiety, depression and mood swings.  For more information visit the Interhealth website, but you should always seek bespoke medical advice from your GP or other medical adviser before taking anything to prevent or treat malaria, especially as strains of malaria differ across the world.

Effective prevention

Effective prevention

Of course, the best way to prevent malaria is not to get bitten by a mosquito in the first place.  Sleeping under impregnated mosquito nets, fitting mesh to windows, and keeping skin covered, particularly around sunset, are suitable barrier methods.  Having an electric fly killer also works, as does regular spraying of rooms with insect killer, though take care not to be in the room for a little while afterwards.  Burning mosquito coils and wearing insect repellent are less dangerous ways of deterring mosquitos.  There is also evidence that eating garlic works, or maybe that’s just wishful thinking!

One of the most effective ways of making sure that mosquitos are eliminated from your environment is to ensure that there is no standing water near your home.  That’s not easy during the rainy season, but mosquitos don’t travel far from their place of birth – some studies say as little as 100 metres.  If you can’t eliminate the water, introduce fish to it to eat the mosquito larvae, or add a small amount of paraffin to it to reduce the surface tension of the water which means the eggs fall through and drown.

Another method is to eliminate the mosquito’s food source – nectar and other plant sugars.  Many of us plant lawns or flower beds round our homes or offices to make them look nice, but that’s just building a mozzie diner.  Contrary to popular belief, mosquitos don’t feed on blood; the females use it for reproduction.  So by replacing your lovely green lawn and flower beds with gravel, you starve the mozzies.  If you must have the greenery, spray it regularly with an insecticide.

Sensible precautions could save thousands of lives a year.  But so could RTS,S.  And the best thing is that all of us who have moaned about our MS Windows over the years have indirectly contributed to its development.  Eat your hearts out, MAC users!

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Postscript

In a recent development, a new test for malaria has been discovered, which promises to be much more accurate than the current standard slide test.  For more information visit http://allafrica.com/stories/201312311173.html