Travelling to a tropical region is a fantastic life experience, but it isn’t without its risks. Taking preparatory measures to protect against indigenous illnesses in such areas is crucial. Among these are typhoid, dengue fever, yellow fever and of course, the focus of this post, malaria.
Those who know anything about malaria will likely have heard about its formidable symptoms (headache, fever, diarrhoea, sickness and muscular pain to name a handful), the fact that it can cause lasting health complications and, if not treated, even be fatal.
As you’ll read elsewhere on this site, the condition is transmitted by mosquito bites, and caused by a parasite (called plasmodium). There are five main types which cause the disease to occur in people, of which the P. falciparum variety is the most aggressive.
Once someone is bitten by a mosquito carrying the parasite, it spreads through the body by taking over blood cells, before eventually attacking the vital organs and central nervous system.
Generally, treatment is very effective when the infection is caught early. However, the harmful nature of the disease, combined with the likelihood that emergency health facilities may not be accessible in more remote areas, makes preventative treatment (what we term ‘prophylaxis’) essential.
No effective vaccination against malaria is available yet, although WHO states that 20 potential candidates are being assessed.
For this reason, preventative treatment is a must when visiting a malarious destination.
There are several different types of antimalarial, and the one you use depends on the area you’re visiting.
Where is malaria a risk?
Below, we’ve put together a malaria world map based on the estimated risk of malaria as defined by the US Centers for Disease Control and Prevention:
[Click to enlarge]
(The data in this malaria world map is correct as of 7/7/16.)
It should be noted that even where the CDC state that the risk of malaria is ‘none’ (such as in Argentina) or there is no data available (Algeria) the disease may still be present in remote areas of the country. Before travel, check the NHS Fit For Travel website for specific health guidance on the destination you are visiting.
Where is malaria most common?
Using data from WHO, we compiled a list of countries where malaria is thought to be present, along with how many reported cases there were in 2014. We then used this to determine the number of cases per 100,000 people in each country:
|Country||Number of confirmed malaria cases in 2014*||Last recorded case if nil or data not available (& number of cases)*||Population**||Approx cases per 100,000||CDC estimated risk***|
|Algeria||0||2012 (55)||39,542,166||N/A||No data|
|Armenia||Not available||2005 (7)||3,056,382||N/A||None|
|Azerbaijan||0||2012 (3)||9,780,780||0||Very low|
|Bahamas||Not available||2011 (6)||324,597||N/A||None|
|Cabo Verde||26||545,993||4.8||Very low|
|Central African Republic||295,088||5,391,539||5473.2||High|
|Congo (Republic of the)||66,323||4,755,097||1394.8||High|
|Congo (Democratic Republic of the)||9,968,983||79,375,136||12559.3||Moderate|
|Djibouti||939 (2013)||828,324||113.4||No data|
|El Salvador||6||6,141,350||0.1||Very low|
|Jamaica||Not available||2012 (5)||2,950,210||N/A||None|
|Oman||0||2010 (24)||3,286,936||0||Very low|
|Papua New Guinea||281,182||6,672,429||4214.1||High|
|Paraguay||0||2011 (1)||6,783,272||0||Very low|
|Russia||Not available||2006 (102)||142,423,773||0||None|
|Sao Tome and Principe||1,754||194,006||904.1||Very low|
|Saudi Arabia||30||27,752,316||0.1||Very low|
|South Sudan||262,520 (2013)||12,042,910||2179.9||High|
|Sri Lanka||0||2012 (23)||22,053,488||0||None|
|Turkey||0||2009 (38)||79,414,269||0||Very low|
|Turkmenistan||Not available||2006 (1)||5,231,422||0||None|
*Data sourced from WHO
**Data sourced from CIA World Factbook
Burundi had the highest density of malaria cases in 2014, with nearly 4.6 million reported cases over a population of 10.7 million. In 2004, there were just 363,395 cases; meaning that Burundi had seen a 12-fold increase in reported cases over the preceding decade.
Despite being the country with the highest concentration, the CDC still only estimates the risk of malaria in Burundi as ‘moderate’; compared to several of its neighboring countries which had fewer cases per capita but are categorised as high. Really, this serves to demonstrate that risk should be taken very seriously when visiting any malarious region, be it yellow orange or red in the malaria world map provided.
Is malaria prevalence rising or falling?
Globally, malaria cases are in decline. Since 2000, WHO state that the number of cases worldwide has decreased by 37%.
But Africa has bucked this trend. Malaria prevalence is rising in several nations and the continent now accounts for almost 9 in 10 of global malaria cases.
Increasing temperatures and climate change have been cited as possible causes of the rise observed in African countries, as warmer weather enables plasmodium-carrying mosquitoes to survive at higher altitudes in these regions.
What prevention measures should I take?
When preparing for your trip, the basics are an essential requirement in addition to prophylactic medicine. Even in those areas where resistance is very low, it’s advisable to wear insect repellent (be it a spray containing an active ingredient like DEET, or a wristband), trousers and long-sleeved garments to reduce the likelihood of bites.
Sleeping under a mosquito net is essential too; make sure one is provided in your hotel room when booking.
Which antimalarial should I use?
It really depends on a number of factors, including:
- the region you’re travelling to
- the length of your trip
- and your medical profile.
Many countries (and sometimes even regions within countries) may contain varieties of the parasite that are resistant to certain types of antimalarial, so it’s important to do your research first. The CDC has detailed information on where known resistance to certain drugs is present, and which drugs are the prefered method of prophylaxis.
Some treatments may also need to be commenced up to three weeks prior to travel, so it’s vital to make preparations well in advance. The closer you get to your travel date, the fewer antimalarial options you’ll have. It may be necessary to continue taking these treatments for some weeks upon your return.
The five main candidates are:
- Malarone (atovaquone and proguanil)
- Doxycycline (an antibiotic)
- Lariam (mefloquine)
- and Primaquine
Chloroquine is one of the older antimalarials on this list and consequently one of the most susceptible to resistance. It is not generally issued as a prophylactic for the more serious form of the parasite, plasmodium falciparum, but is still sometimes useful in preventing more benign versions. For this reason, it may be more typically issued in combination with other treatment, such as proguanil, to provide comprehensive protection.
During consultation, a doctor will ask which area the patient is travelling to in order to supply the most suitable treatment.
How do they work?
Once bitten, the malaria parasite enters the body through the bloodstream then journeys to the liver. Here, the parasite replicates itself before exiting the liver to return to the bloodstream in greater numbers.
When used as a prophylactic prior to exposure, antimalarials work in the liver to destroy the parasite before it can duplicate itself and spread through the body.
However, in patients where infection has passed beyond this stage, the parasite will become more robust, necessitating urgent medical attention, and often antimalarial medicines given at higher doses. These will attack the parasite once it has re-entered the bloodstream in order to prevent it from multiplying and spreading through the body.
In summary, malaria is a condition which is much simpler to prevent than it is to treat. For this reason, it’s always better to be prepared than take the risk.
You can find out more on the above treatments, including information on possible side effects, by referring to our medicine pages.