Started Late on Anti-malaria Medication

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QUESTION:

I’m in a malarious country and I had no idea about anti-malarials until I got here, so I started taking anti-malaria(doxycicline) two weeks late. It has been three weeks since I started taking the medicine. Do you think it would work or should I stop taking it?

ANSWER:

It depends a bit on where you are, and what types of malaria are in your region. Plasmodium falciparum usually takes between 7 and 14 days for symptoms to develop after exposure; P. vivax and P. ovale take between 9 and 14 days. P. malariae, on the other hand, sometimes doesn’t show symptoms until 30 days after infection. However, the most acute and dangerous form of malaria is that caused by P. falciparum; as such, if you haven’t had any symptoms since you started taking anti-malarials three weeks ago, you should be ok, and it certainly would be advisable that you continue with the preventative medicine while you remain in the malarial area.

It’s also worth mentioning that because of the lag between infection and symptoms, in many cases you need to continue taking antimalarials for some period of time after you leave the malaria zone. Of course, if at any point you start to develop symptoms, such as fever or chills, go to a hospital or see a doctor for prompt diagnosis.

What is Malaria?

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QUESTION:

What is malaria?

ANSWER:

Malaria is a disease caused by parasites of the genus Plasmodium. Transmitted by mosquitoes, there are several different kinds of malaria distributed throughout the tropical and sub-tropical regions of the world, causing somewhere between 300-500 million cases of disease each year, and as many as 1 million deaths. In fact, malaria is one of the biggest killers of children under the age of five in sub-Saharan Africa, one of the regions of the world where the burden from malaria is the highest. Malaria is usually an acute disease, manifesting itself with severe fever, chills, headache and often nausea as well. Some types of malaria can have relapsing episodes over a time period of many years.

Having said this, malaria is easily preventable, through avoiding mosquito bites by wearing appropriate clothing and sleeping under insecticide-treated bednets, or through taking preventative medication (called prophylaxis). Malaria is also treatable once symptoms appear, through ingesting safe, effective and relatively cheap drugs. With such control measures at hand, you may ask why malaria is still such a huge problem in our world; the answer is that delivering control strategies and treatment to populations most at risk is difficult, and often countries with high malaria burdens don’t have efficient and effective health systems in place to coordinate control efforts.

International non-governmental organisations such as the World Health Organisation, as well as a multitude of non-profit organisations such as the Malaria Consortium and Malaria No More, work tirelessly to bring malaria control and treatment to the places that need it most, with the aim to eradicate malaria as a disease of public health importance.

Malaria Prevention for Seniors

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QUESTION:

I am a healthy senior citizen (73 years) and I am considering a trip with Semester at Sea. One of the ports they plan to visit is Ghana. I see the CDC says Ghana is a “high risk” area for malaria.

I think I remember being told (at the U of W Travel Medicine Clinic) a few years ago that the malaria drugs are problematic for Seniors.

With the Semester at Sea ship stopping at Takoradi, Ghana, how high a risk is malaria and what preventative measures could/should I take?

I have had no malaria treatment (preventive or due to illness) in the past.

Thank you.

ANSWER:

It is correct that Ghana is a high risk zone for malaria, and wise of you to investigate ways to prevent infection. This is especially the case given that there is evidence to suggest that senior citizens and travellers over the age of 60 may be more at risk of serious complications from malaria. As such, it is especially important for these high risk groups, which also includes pregnant women and children, to be well aware of ways to reduce the risk of exposure and infection.

Having said that, I have done some research and I don’t think there is any evidence that the standard drugs for preventing malaria work less well in older people. In fact, one study I found suggested that younger people were more likely to report side effects from taking malaria preventative medicine (see Mittelholzer et al., “Malaria prophylaxis in different age groups” in volume 3 of the Journal of Travel Medicine, published in 2006).

The only potential problem could be cross-reaction of the malaria drugs with other prescribed medicine. As such, I would recommend you enquire with your doctor prior to the trip, to ask about being prescribed drugs to prevent malaria that are appropriate for the region you are travelling to (probably Malarone, Lariam or doxycycline, since you will be travelling to an area with chloroquine-resistant forms of malaria) that furthermore won’t harmfully interact or have reduced efficacy when ingested alongside other medication you might already be taking.

How to Prevent Malaria

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QUESTION:

What is the prevention of malaria?

ANSWER:

Malaria can be prevented in a number of ways, the main three of which are bite reduction, prophylaxis and vector control.

Bite reduction just means steering clear of mosquitoes, and specifically those that transmit malaria. These bite mostly between dusk and dawn, so if walking around at these times of day in a malarial area, it is worth wearing long sleeves and pants, and applying an insect repellant – ones containing DEET are the most effective at keeping off mosquitoes, in my opinion, but they also contain very toxic chemicals so should be used with care.

Specifically, 100% DEET shouldn’t be applied directly to bare skin, since it can be absorbed and cause problems for the liver. Natural insecticides, such as those containing citronella, are also an option. At night, it is advised to sleep under a bednet, which prevents mosquitoes from biting you while you sleep. Nets which are infused with pyrethrin, or other insecticides, are recommended.

Pyrethrin spray can also be used on clothing, to stop mosquitoes biting through light cloth. On a broader scale, bite reduction can also be achieved through better screening of windows and doors, and other ‘environmental’ controls.

Prophylaxis, when referring to malaria, means taking certain medication in order to prevent the onset of the disease. Several different drugs exist, and different ones are recommended depending on the type of malaria you are likely to encounter. Moreover, each has different potential side effects, different schedules of ingestion and come at a range of prices.

Since they do cost money, and are sometimes very expensive, prophylaxis against malaria is usually only used by short term visitors to malarial zones, although since pregnant women are more susceptible to malaria, they may choose to take prophylaxis during their term in order to prevent infection – it should be noted that most of the drugs used for malaria prophylaxis are NOT recommended for pregnant women so it is important to check carefully before starting on any of these medications.

For more info on malaria prevention while pregnant, why not check out the Q&A question about pregnancy and travelling to Belize?

For info on malaria prophylaxis in general, there is a Prophylaxis Forum dedicated to this here on this website, so have a look!

Finally, there is vector control. This means reducing the number of mosquitoes around so that there are less to transmit malaria! Spraying households with insecticides has been very effective in reducing malaria transmission in a number of settings, and although it suffers from a lack of cost-effectiveness and sustainability in the long run, may still be very useful in high-endemicity regions or those where drug-resistant malaria is rife.

Another approach to vector control is to eliminate habitat for the mosquito larvae. The larvae breed in pools of stagnant water, such as ditches or puddles; filling these in can reduce the number of larvae that can mature into biting mosquitoes. Obviously, some water sources, such as wells and irrigation ditches, are required by communities, particularly in rural areas, and so cannot be removed. As such, larval control is probably mostly an effective strategy in urban transmission settings.

Finally, on a slight tangent to traditional vector control, there has long been interest in the idea of controlling malaria through manipulation of mosquito genetics in such a way that populations could be replaced with individuals that cannot transmit the disease. A research article on this subject is available on this website. See: Malaria Control with Transgenic Mosquitos.

 

Traveling and Pregnant

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QUESTION:

Hi, I am 3 months pregnant but thinking about going on vacation to Belize in a few weeks time. Should I think about taking something against malaria?

ANSWER:

It’s good you asked because getting malaria while pregnant can be much more serious than when not pregnant, and can cause terrible problems to both you and your baby.  Therefore, it is always advisable to consult your own health care provider before traveling.

The good news is that while there is malaria in Belize it is not found everywhere and where it is found, it is not resistant to chloroquine, a drug considered safe to use during pregnancy.

According to the US Centers for Disease Control (CDC),   Belize City and the islands where tourists mostly visit are largely malaria free, and the risk of getting malaria in these areas is ‘low’. So, if you are heading to Belize City or a resort on one of the islands, you may just want to follow practical advice to avoid mosquito bites: sleep in a screened room and under an insecticide treated bed-net, avoid being outside between dusk and dawn, and if you are, wear long-sleeves and long pants or skirt, and use mosquito repellent (containing DEET, and especially during pregnancy, in my opinion a  roll-on repellent if preferable to a spray to avoid inhaling the chemicals).

However, if you are heading off the beaten track, you should take all the mosquito bite precautions mentioned above but also take chloroquine as prophylaxis. Take chloroquine (500 mg tablet containing 300 mg base drug) one time a week starting 1 – 2 weeks before traveling to an area with malaria. Continue taking one pill once a week (on the same day and the same time) while in country and for another 4 weeks after leaving the malaria area.

 

Malaria in Brazil

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QUESTION:

Is there Malaria in Brazil? If so, what pills do I need to take?

ANSWER:

Yes, there is malaria in many parts of Brazil, and more than one type: about 75% of cases in Brazil are caused by Plasmodium vivax, whereas the rest are from infections with P. falciparum, the more acute and dangerous species of malaria. Brazil does have good information as to the distribution of malaria across the country; in terms of affected states, the full list is as follows:

Acre, Amapa, Amazonas, Maranhao (western part), Mato Grosso (northern part), Para (except Belem City), Rondonia, Roraima, and Tocantins.

This includes cities within the above districts, such as Boa Vista, Macapa, Manaus, Maraba, Porto Velho and Santarem, and particularly on the outskirts where transmission is highest. It is worth noting that malaria is not considered to be a problem in the region of Iguassu Falls.

In terms of malaria prevention, the CDC recommends Larium (mefloquine is the generic name), Malarone (atovaquone or proguanil are the generic names) or doxycycline, due to the presence of chloroquine-resistant P. falciparum in some areas. Deciding between which of these to take depends on a number of factor, including cost, known side-effects, and, not least of all, personal preference. For a discussion on the pros and cons of these various form of prophylaxis, check out the discussion “Malaria Prophylaxis” on this website.

Malaria in Thailand

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QUESTION:

I am going to Thailand. Do I need to take Malaria medication there?

ANSWER:

Like many other countries, that depends on where in Thailand you are planning to go. The country on the whole has been successful in containing malaria, mostly through successful mosquito control initiatives and a great initiative of government-sponsored “malaria clinics”  dotted around the country, which diagnosed and treated thousands of people.

Now, malaria is more or less constrained to the border regions with Myanmar, Laos and Cambodia, and if you plan to travel to these areas, prophylaxis is recommended (malarone or doxycycline are best since the area has chloroquine-resistant strains of Plasmodium falciparum, the most quick-acting and dangerous form of malaria). There are a few cases of malaria from coastal areas every year, but bite prevention is probably sufficient to reduce the risk of infection – make sure to wear insect repellant, especially at night and dusk/dawn, and if possible sleep under an insecticide-treated bednet.

Finally, remember if you do take prophylaxis, and as per the manufacturer’s instructions, there is only a tiny risk of contracting malaria. But if you do find yourself with symptoms when you get back (see the ‘What are the symptoms of malaria?’ question in this Q&A forum for a description of the more common signs of malarial infection), it’s definitely worth getting checked out!