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.

Three Stages of Malaria

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QUESTION

What are the three stages of malaria?

ANSWER

The three parts of the malaria life cycle are known as the exo-erythrocytic cycle, the erythrocytic cycle and the sporogonic cycle. The first two of these take place in the human (or other mammal) host, while the third occurs in the mosquito vector. The below diagram, courtesy of the CDC, shows the complete life cycle of malaria in more detail.

malaria life cycle CDC

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

P. Falciparum Malaria Treatment

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QUESTION

I dont have high fever yet have been diagnosed with P. falciparum malaria. How can this disease be treated and is it completely curable?

ANSWER

Don’t worry, if diagnosed early and given appropriate treatment, P. falciparum infection is very easily cured. You should be given a type of medication called artemisinin-based combination therapy (ACT). An example is Coartem, which is a combination of artemether and lumefantrine.

Other artemisinin derivatives that are commonly used include artesunate and dihydroartemisinin. You should start to feel better after just a few days and will make a complete recovery. Make sure you get the correct dose for your age and weight from the doctor, and take the medication for the full length of time the doctor tells you – this is very important to make sure the infection is completely cured, otherwise the infection may be able to come back.

What is malaria, and what causes it?

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QUESTION

What is malaria and what causes it?

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).

Cyclical Fever and Malaria Symptoms

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QUESTION

My dad is not well from last one month. In the evening time he feels headache, neck pain and 102 Temp.

Can you please tell me can it be Malaria.

ANSWER

Those symptoms can be characteristic of malaria—cyclical fever is a key symptom, though usually the cycles are every other day or even every third day (depending on the type of malaria). However, in some cases the cycles are more frequent or the patient may even have constant fever.

One of the difficulties with diagnosing malaria is that its symptoms are very general and can therefore be mistaken for many other illnesses. Likewise, in areas of high malaria transmission, doctors may assume a feverish illness is malaria without thinking about other possible diseases. As such, it is crucial that you take your father for a blood test, which is the only accurate way to diagnose malaria.

The doctor or clinician will either make a blood film and look at it under the microscope, or use a tiny drop of blood in a rapid diagnostic test. Either way, it is important for them to see evidence of a malaria infection before they give your father treatment. The diagnostic test should also show which type of malaria your father has (if indeed he has malaria), and this will also help to determine which is the most appropriate type of medication.

Malaria in Borneo, Indonesia

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QUESTION

We fly to Borneo tomorrow and have been very stupid not thinking about Malaria medication. Can someone quickly tell if I should take medication when there and also what type would be best to take?

Thank you for your help.

ANSWER

Yes! Malaria prophylaxis is recommended for trips to Indonesian Borneo, particularly rural areas. Recommended forms of prophylaxis are Malarone (atovaquone-proguanil), doxycycline and Lariam (mefloquine). The first is the most expensive, but has the fewest side effects, the second is the cheapest but can induce sun sensitivity and needs to be taken for 4 weeks after returning home and the third only requires one pill a week (the others are taken daily) but side effects can be severe and disturbing, including vivid dreams, impaired consciousness and hallucinations.

I am less familiar with south-east Asia, but I know in Africa doxycycline is readily available, for very little money, at local pharmacies. Therefore if you don’t have time to get the necessary anti-malarials before you leave, don’t panic! You may well be able to buy them in-country, particularly if you stop in Jakarta or another major city on your way. Check expiry dates and make sure the drugs are in the original packaging before you purchase though, as counterfeit drugs are distressingly prevalent. Also, do not buy chloroquine (or indeed any anti-malarial not listed above)—malaria in Borneo has been reported to be resistant to chloroquine and so this is not an appropriate anti-malarial for this area.

Please consider sharing your experiences with whichever prophylactic you choose when you return from your trip. We at MALARIA.com are trying to compile data on people’s experiences with malaria prophylactics and treatment medication, and we would be very grateful if you would take our malaria survey. Thank you!

Please also use other preventative measures against malaria while you are in Borneo—sleeping underneath an insecticide-treated bednet and wearing long-sleeved clothing in the evenings and at night, plus applying insect-repellent to exposed skin, can all help to reduce the incidence of mosquito bites and thus the risk of contracting malaria. Plus, avoiding insect bites will probably improve your enjoyment of the trip as a whole!

Malaria After Doxycycline?

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QUESTION

I recently spent a month in Asia. I took doxycycline tablets for malaria. I took them for the month I was away and when I returned. I took the full course and had been fine. Within two days of completing the course I became ill. This has be going on for about a month now with severe headaches, nausea, dizziness, very tired all the time and feeling like I’m going to faint. I have been to the doctor five times, they think this is a virus, I have been tested for malaria and dengue fever. I am only just now starting to feel better. What could this be?

ANSWER

Since you are beginning to feel better, I would go with your doctors’ diagnosis of a viral infection of some kind. It is also possible that you were infected with intestinal amoebas or even worms. A more accurate diagnosis would require faecal sample and possibly blood tests. You did the right thing by getting tested for malaria and making sure you didn’t have dengue.

US Army Doctor William Crawford Gorgas: Sent to Panama to fight Malaria

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QUESTION

What was the doctor’s name who was sent to Panama to fight Malaria when Panama Canal was being built?

ANSWER

I believe the person you are referring to is Dr. William Crawford Gorgas. Dr Gorgas was the chief sanitary officer for the Panama Canal project and had gained experience in controlling vector borne diseases while working in Havana, Cuba, where yellow fever was a problem.

It had also been shown a few years earlier, in 1898, that mosquitoes carried malaria as well. In Panama, Dr Gorgas focused his efforts on controlling mosquitoes, through drainage of standing water, adding larvicide and oil to remaining water and hand-collection of adult mosquitoes. In addition, Dr Gorgas screened all government buildings and workers’ quarters to prevent mosquitoes from entering, and gave workers prophylactic quinine. He was assisted in these endeavours by Dr Joseph Augustin LePrince and Dr Samuel Taylor Darling; together, their efforts led to the elimination of yellow fever from the canal zone and a great decrease in the number of malaria cases, though malaria continued to be a problem throughout the construction of the Panama Canal.

Malaria Causes

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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).

How to Protect from Malaria

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QUESTION

How can I protect my body from malaria?

ANSWER

There are a number of ways to prevent malaria. These can be placed into two categories: medication and vector protection.

For medication, there are drugs you can take to prevent the malaria parasite from developing after someone is bitten by an infected mosquito. These drugs are known as “chemoprophylaxis”.

There are several different kinds, such as doxycycline, mefloquine (marketed as Lariam), atovaquone-proguanil (marketed as Malarone) and chloroquine—the type you use depends on the type of malaria present in the area. For example, in much of Africa and India, malaria is resistant to chloroquine, so this cannot be used as a prophylactic. In parts of Thailand, resistance to mefloquine has emerged. However, if the appropriate type of prophylaxis is used, it is very effective against malaria.

The problem is that these drugs have not been tested for long-term use, can be expensive and may have side-effects. Therefore they are of limited use for people who live in areas where malaria is endemic, and are more appropriate for travelers who are in malarial areas for short amounts of time. However, anti-malarial medication may be used in a very specific way for people at particularly high-risk for malaria, such as pregnant women and young children. In these cases, the high-risk individuals receive a dose or series of doses of malaria medication in order to prevent malaria. This form of prevention is known as intermittent preventive therapy (IPT).

Vector prevention involves protecting oneself against getting bitten by mosquitoes. This can involve wearing long-sleeved clothing in the evenings and at night, when malaria mosquitoes are most active, or wearing insect repellent on exposed skin. Indoor residual spraying, whereby repellent and insecticides are sprayed inside the house, can also be used to bring down the number of mosquitoes.

Another very effective technique for preventing malaria is to sleep under a long-lasting insecticide-treated bednet. The mesh acts as a barrier against the mosquitoes, and the insecticide impregnated in the mesh further repels the mosquitoes and prevents them from biting through the mesh.