Bringing Malaria to the United States

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QUESTION

I was recently diagnosed with Malaria still waiting to find out what strand, but either got it in Uganda or Rwanda. I have recently came back to the states and have been bit by mosquito. I have already started to take some medication for it, but I am concerned about spreading the virus to others in the states including my family. Is it possible that if I still have the infection to spread it to others or in the states? If so what should I do.

ANSWER

There actually used to be malaria in the United States, particularly in the southern areas, but concerted mosquito control efforts as well as public health initiatives eradicated it in the 1950s. I don’t think you need to worry too much about transmitting malaria—once you are on treatment, the number of parasites in your blood drops dramatically and it becomes more difficult to transmit the parasite to a mosquito. Also, there are lots of types of mosquitoes in the US, and only those of the genus Anopheles can transmit malaria. As such, if you are concerned about spreading malaria, you should take precautions to protect yourself from mosquitoes especially at night and at dusk and dawn, as this is when Anopheles mosquitoes are most active. The type of mosquitoes which bite during the day usually belong to the genus Aedes, and cannot transmit malaria. During these high risk times of day, you should take care to wear long-sleeved clothing, and also wear insect repellent, preferably containing DEET.

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.

Does Malaria Still Exist?

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QUESTION

does malaria still exist?

ANSWER

Yes, malaria still exists, and is responsible for 250 million cases of illness every year, of which about 700,000 result in death. So it is a very serious global health problem!

Some countries, such as the United States, have managed to successfully eliminate malaria through a combination of vector control strategies (i.e. spraying for mosquitoes, reducing the presence of water bodies where mosquitoes breed, etc) and better health infrastructure for diagnosis and treatment. This strategy has also been successful in other settings, such as the Mediterranean and much of the Middle East, as well as even in some high transmission tropical settings such as Malaysia (particularly in urban areas).

The widespread distribution of long-lasting insecticide treated bednets has further assisted in malaria prevention in high transmission areas. However, much of the rest of the world is still struggling to control malaria, though the number of deaths is dropping every year, and some organisations hope to reduce malaria mortality to zero by the year 2015.

If you have taken medications for malaria, please help Malaria.com by taking our Malaria Survey. Thank you!

Cases and Deaths of Malaria in the USA, 2005-2010

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QUESTION: Where can I find a list of reported cases and deaths from Malaria in the USA, 2005-2010? I understand that most cases were acquired outside the US and the remaining were transmitted via blood transfusions. But I can not find a source for the data.

Tom Yerg

ANSWER: We found statistics for the years 2005-2009. The number of reported cases in the United States, according to the Centers for Disease Control are:

  • U.S. Malaria Cases – 2005: 1,528 (7 fatal)
  • U.S. Malaria Cases – 2006: 1,564 (6 fatal)
  • U.S. Malaria Cases – 2007: 1,505 (1 fatal)
  • U.S. Malaria Cases – 2008: 1,298 (2 fatal)
  • U.S. Malaria Cases – 2009: 1,484 (4 fatal)

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