Malaria Prophylaxis in Pakistan

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QUESTION

Do I need antimalarials if i am returning to my home country in pakistan after two years?

ANSWER

That depends on where you will be going in Pakistan and how long you are planning on staying. Malaria is a risk at all areas under 2,500m of altitude. However, antimalarials are not recommended to be taken on a long-term basis, so if you are relocating home permanently and will be in an area at risk of malaria transmission, you should look into other preventative measures. This includes sleeping under a long-lasting insecticide-treated bednet at night, which prevents infected mosquitoes from biting you, and also potentially spraying indoors to kill mosquitoes. Making sure all rooms are well-screened can also keep mosquitoes out, and wearing long-sleeved clothing and insect repellent on exposed skin will further reduce bites. If you suspect you might have malaria (for example if you experience high fever, particularly coming in cycles interspersed with chills), you should immediately visit a doctor or clinic to test for malaria, so you can receive prompt and accurate treatment.

If you are staying in Pakistan for a short period of time (< 6 weeks) you could certainly consider taking an anti-malarial drug to prevent malaria. Doxycycline, mefloquine (sold as Lariam) and atovaquone-proguanil (sold as Malarone) are all recommended as appropriate prophylactic medications against malaria in Pakistan.

Is there Malaria in United Arab Emirates (UAE)?

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QUESTION

Is the UAE malaria free?

ANSWER

Yes—the UAE is not considered a transmission area for malaria. However, other insect-borne diseases can occur in this region, such as West Nile virus, so while in the UAE it is still worth taking preventative measures against insect bites, such as wearing long-sleeved clothing and using insect repellent on exposed skin.

Malaria in Namibia or South Africa

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QUESTION

Is there a risk of catching malaria in Namibia or South Africa

ANSWER

Yes. According to the CDC, malaria is present in the following areas of Namibia: Kunene, Ohangwena, Okavango, Omaheke, Omusati, Oshana, Oshikoto, and Otjozondjupa and the Caprivi Strip. In addition, malaria is present in South Africa in northeastern KwaZulu-Natal Province as far south as the Tugela River, Limpopo (Northern) Province, and Mpumalanga Province. It is also present in Kruger National Park.

If you are visiting these areas, it is recommended you take prophylactic medication (such as doxycycline, mefloquine or atovaquone-proguanil) and sleep under a bednet. Other preventative measures against mosquito bites, such as wearing long-sleeved clothing and insecticide on exposed skin (especially in the evenings and at night) are also recommended.

Malaria and Nkadu Luo

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QUESTION

When did professor Nkadu Luo discover that female mosquito causes malaria?

ANSWER

Professor Nkadu Luo is a microbiologist and immunologist in Zambia. Most of her work has been on HIV/AIDS and sickle cell anaemia. She has also been a key figure in promoting screening of blood banks in Zambia for infectious diseases such as HIV and malaria. However, the discovery that female mosquitoes transmit malaria was made much earlier—taxonomists as early as the mid-19th century were aware of differences in the mouthparts between male and female mosquitoes of certain species, which allowed them to determine that they were feeding on different things (female mosquitoes who feed on blood have very specialised mouthparts, for example).

Then, in the late 1890s, a British doctor called Ronald Ross discovered that mosquitoes transmit malaria parasites when they feed on blood. Prof Luo probably learned about the cycle of malaria transmission during her extensive biomedical training.

Symptoms and Causes of Malaria

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QUESTION

What are the symptoms and causes of malaria?

ANSWER

Malaria is caused by a parasite called Plasmodium, which is transmitted via the bites of infected mosquitoes. In the human body, the parasites multiply in the liver, and then infect red blood cells. Usually, people get malaria by being bitten by an infective female Anopheles mosquito. Only Anopheles mosquitoes can transmit malaria and they must have been infected through a previous blood meal taken on an infected person. When a mosquito bites an infected person, a small amount of blood is taken in which contains microscopic malaria parasites. About 1 week later, when the mosquito takes its next blood meal, these parasites mix with the mosquito’s saliva and are injected into the person being bitten.

Because the malaria parasite is found in red blood cells of an infected person, malaria can also be transmitted through blood transfusion, organ transplant, or the shared use of needles or syringes contaminated with blood. Malaria may also be transmitted from a mother to her unborn infant before or during delivery (“congenital” malaria).

There are five kinds of malaria known to infect humans: Plasmodium falciparum, P. vivax, P. ovale, P. malariae and P. knowlesi. The symptoms of malaria differ depending on the type of malaria; P. falciparum  is the most deadly and severe form of the disease. General symptoms of malaria include  include fever and flu-like illness, including shaking chills, headache, muscle aches, and tiredness. Nausea, vomiting, and diarrhea may also occur. Malaria may cause anemia and jaundice (yellow coloring of the skin and eyes) because of the loss of red blood cells.

Symptoms usually appear between 10 and 15 days after the mosquito bite. If not treated, malaria can quickly become life-threatening by disrupting the blood supply to vital organs.

What are the causes of malaria?

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QUESTION

What are the causes of malaria?

ANSWER

Malaria is caused by a parasite called Plasmodium, which is transmitted via the bites of infected mosquitoes. In the human body, the parasites multiply in the liver, and then infect red blood cells. Usually, people get malaria by being bitten by an infective female Anopheles mosquito. Only Anopheles mosquitoes can transmit malaria and they must have been infected through a previous blood meal taken on an infected person. When a mosquito bites an infected person, a small amount of blood is taken in which contains microscopic malaria parasites. About 1 week later, when the mosquito takes its next blood meal, these parasites mix with the mosquito’s saliva and are injected into the person being bitten.

Because the malaria parasite is found in red blood cells of an infected person, malaria can also be transmitted through blood transfusion, organ transplant, or the shared use of needles or syringes contaminated with blood. Malaria may also be transmitted from a mother to her unborn infant before or during delivery (“congenital” malaria).

There are five kinds of malaria known to infect humans: Plasmodium falciparum, P. vivax, P. ovale, P. malariae and P. knowlesi.

Malaria in Africa

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QUESTION

What is the current problem for malaria in Africa?

ANSWER

Malaria is a particularly severe problem in Africa due to a number of reasons. First of all, transmission in many parts of Africa occurs year round, due to favourable conditions for the development of the mosquitoes malaria requires as its vector.

Secondly, the dominant and most widespread species of malaria in Africa is Plasmodium falciparum, which is most fast-acting and deadly form of the disease.

Thirdly, Africa has a very young population; birth rates are high across much of the continent, and in many countries, more than 40% of the population is under 15 years old. Given that young children are are higher risk of malaria than adults, this also increases the burden of malaria in Africa compared to other parts of the world.

Finally, access to health care and malaria control interventions in Africa has been plagued by more general issues of slow development. While national health systems are slowly emerging, many countries are still reliant on foreign aid and NGOs to provide even basic health services.

Even where these organisations can provide health care, they often face challenges such as reaching remote populations without good road access, finding ways to provide medical services without reliable electricity or communications networks and maintaining supply chains of diagnostic tools and crucial medicine.

However, signs of progress are being seen. Long-lasting insecticide treated bednets have been put forward as a key preventative measure against malaria, and to date millions have been distributed to people living in malarial areas in Africa, and particularly to high risk groups such as young children and pregnant women.

Simultaneously, other control initiatives, such as indoor residual spraying, are gaining traction and being deployed in more areas. An emphasis on local capacity building has encouraged community involvement in drug distribution and access to health care initiatives, as well as training local health workers in diagnostic methods in rural areas.

Encouraging reports from groups such as Malaria No More and the Roll Back Malaria consortium suggest that the number of deaths from malaria in Africa last year was the lowest in history, and efforts are underway to reduce that number to zero, worldwide, by the year 2015.

Transmission of Malaria

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QUESTION

Why can the malaria parasite be transmitted from mosquito to human, but not from human to human (via blood)?

ANSWER

This is a very good question, and actually, malaria can be transmitted via human blood directly to another person, but this occurs relatively rarely!

It has to do with the life cycle of the malaria parasite. When a mosquito bites a human host, it injects sporozoites from its salivary glands into the blood. This life stage first migrates to the liver, where it undergoes a cycle of multiplication, before entering the blood stream. Here, in the so-called “erythrocytic” portion of the life cycle, the parasite reproduces a series of times in red blood blood, before finally forming gametocytes, which are required to be ingested by a mosquito vector during another blood meal for the life cycle to be continued. As such, when blood is passed between people, they would have to pass infected red blood cells, and not gametocytes (which are not infective to humans, only to mosquitoes) in order for the other person to become infected.

As such, when a person who is infected with malaria donates blood, there is a chance that they might pass on some red blood cells which are infected with mature trophozoites or schizonts; these could then go on to infect more red blood cells in the person who received the blood. However, in most countries, blood is screened for malaria, and in fact, in many places, people who might have been exposed to malaria are not allowed to donate whole blood, only plasma (in which the red blood cells have been removed, and therefore there is no risk of transmission). Given the high levels of malaria prevalence in some endemic countries, however, preventing people from donating blood who are positive for malaria may result in too little blood being collected; in these cases, other strategies, such as treating donors or closely monitoring patients post-transfusion, may prove to be a better strategy.

malaria life cycle schematic CDC

Schematic of the malaria life cycle, courtesy of CDC (www.cdc.gov)

Annual Blood Examination Rate in Bengal

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QUESTION

What is the annual blood examination rate in West Bengal?

ANSWER

The annual blood examination rate (ABER) is a measure of the level of diagnostic monitoring activity. Data from 2007 suggested the ABER in West Bengal was around 5%, which is well below the level of 10% which is recommended for active surveillance and is the target of the National Vector Borne Disease Control Programme.

However, within West Bengal there is variation in the ABER both geographically and temporally. One study showed that in Naxalbari block in Darjeeling district, ABER in 2003 and 2004 was as low as 3.5%. The region experienced a malaria outbreak in late 2005, and the average ABER for this year soared as high as 16%; however, from January to May of 2005, before the transmission season and the outbreak, the ABER was only 0.5%! This means that monitoring efforts at the start of the outbreak were probably insufficient to detect the emergence of the outbreak and therefore delayed the process of responding to the emerging disease threat. Maintaining sufficient levels of malaria surveillance monitoring is particularly important in West Bengal, since this state is one of the major endemic centres for malaria in India, contribution about 11% of all malaria cases and about 6% of all cases of Plasmodium falciparum.

Malaria Transmission

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QUESTION

Can one get malaria through contact with the infected person or is it airborne?

ANSWER

Malaria cannot be transmitted through direct contact with an infected person, nor is it airborne! It is actually transmitted directly via the bite of an infected mosquito. Only certain female mosquitoes, of the genus Anopheles, can carry malaria. The mosquito picks up the malaria parasite (there are five different types of malaria that infect humans, though all are transmitted in exactly the same way) when it feeds on the blood of an infected person. The parasite then undergoes a cycle of reproduction in the mosquito, before new parasites migrate once again to the mosquitoes salivary glands. From here, they are able to escape into the blood of a new human host when the mosquito takes another blood meal by biting the person.

Since malaria is transmitted by blood, there have been a some reports of malaria transmission via organ donor or blood transfusion, though most countries now screen for malaria before using donated blood or organs. Additionally, if a pregnant woman gets malaria, the parasite can be passed to her baby either across the placenta or during delivery; this is called “congenital malaria”, and can be quite harmful to the baby. As such, and also because pregnant women themselves are especially vulnerable to malaria, many campaigns have dedicated themselves to providing pregnant women with long-lasting insecticide treated bednets and other measures to prevent and treat malaria.