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Malaria Surveillance in the United States.

Do you travel outside the United States to visit friends and relatives? Be aware of ways to prevent travel-related diseases like malaria.

Chart: Reported Malaria Cases -- United States, 2007

Though malaria transmission in the United States was successfully interrupted in the 1950's, CDC continues to conduct malaria surveillance in order to detect locally acquired cases. Since the Anopheles mosquito that carries the malaria parasite still exists in the United States, there is a constant risk that malaria could be re-introduced.

In 2007, CDC received reports of 1,505 cases of malaria among person in the United States. All but one of these cases were acquired outside of the United States; one was acquired through a blood transfusion.

More than half of the cases were reported by 6 jurisdictions:

  • New York – (326; 233 of these were from New York City)
  • California (157 cases)
  • Texas (136 cases)
  • New Jersey (77 cases)
  • Maryland (67 cases)

For each case, data were collected about the reason for travel in order to characterize the types of people who may be at higher risk for infection with malaria. Reasons for travel include tourism, business, visiting friends and relatives (VFR), immigrant/refugee, and military.

More than half of the cases from the states with the highest number of cases reported were in people who were visiting friends and relatives. A closer look at the persons who were visiting friends and relatives in the top 6 states shows that almost 70% of the travelers had travelled to West Africa.

The term VFR describes an immigrant, ethnically and racially distinct from the majority population of the country of residence, who returns to their country of origin to visit friends or relatives (1). VFR travelers also may include the spouse and children who were born in the country of residence. VFR travelers to developing countries are at greater risk for travel-related infectious diseases (such as malaria, typhoid fever, hepatitis A, and tuberculosis) compared with persons traveling for other reasons. This may be due to the belief among many VFR travelers that they have total or partial immunity to such diseases as malaria since they originally lived in malaria-endemic areas growing up. However, this is not true: although people growing up in malaria-endemic countries can develop some partial immunity after surviving repeated infections, that immunity quickly wanes after living in an area without continued exposure to malaria (2).

It is important for both travelers and health-care professionals to be aware of travel-related infections. Making VFR travelers aware that they may be at risk for serious infections not only because of waning immunity but also due to the changing of disease patterns and drug resistance in their home country is important for disease prevention. Additionally, travelers should be aware that older drugs such as chloroquine, proguanil, and pyrimethamine are often no longer effective, especially in sub-Saharan Africa, where risk of infection with P. falciparum -- the most dangerous malaria parasite -- is high (3). Usage of the correct, high quality drugs to prevent malaria, as well as usage of other prevention precautions (such as using insecticide-treated bed nets and insect repellent), are key to safeguarding health when traveling to regions where there is malaria risk.

Map: Number of Malaria Cases by State -- United States, 2007

Data Source:

CDC. Malaria surveillance—United States, 2007. MMWR 55(No. SS-2);1–16.

More Information

References:

  1. Leder, K, Tong, S, Weld, L, Kain, KC, et al. Illness in travelers visiting friends and relatives: A review of the GeoSentinel surveillance network. Clin Infect Dis 2006; 43:1185.
  2. Bacaner, N, Stauffer, B, Boulware, DR, et al. Travel medicine considerations for North American immigrants visiting friends and relatives. JAMA 2004; 291:2856.
  3. CDC. Health information for international travel, 2008. Atlanta, GA: US Department of Health and Human Services, Public Health Service, CDC; 2007.
  • Page last reviewed: April 21, 2009
  • Page last updated: April 21, 2009
  • Content source:
    • Office of the Associate Director for Communication, Digital Media Branch, Division of Public Affairs
    • Page maintained by: Office of the Associate Director for Communication, Digital Media Branch, Division of Public Affairs
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