Reports of Malaria in the Dominican Republic

Updated: February 18, 2005

The Public Health Agency of Canada (PHAC) continues to closely monitor for reports of malaria in tourists who have visited the province of La Altagracia in the Dominican Republic. PHAC was notified by the U.S. Centers for Disease Control and Prevention of a fifth confirmed case in an American traveller who travelled to Punta Cana for one week and returned to the US on January 10, 2005. In addition, the Agency was notified of an additional two confirmed cases of malaria in European travellers who traveled to Punta Cana and La Romana respectively. Although the cases have been recently reported, infection occurred in late November.

No further cases have been reported in Canadian travellers. Of the six lab-confirmed cases of P. falciparum malaria in Canadian travellers who travelled to Punta Cana in the DR, all have recovered.

To date, five cases have been reported in American travellers; four cases from Punta Cana and one case from San Francisco de Macoris. Ten cases have been reported in European travellers; eight cases from Punta Cana, one case from Playa Bavaro, and one case from La Romana Province.

At this time, a combined total of 21 cases of malaria have been reported in Canadian, American and European travellers to the following areas of the Dominican Republic: Punta Cana (18 cases), San Francisco de Macoris (1 case), Playa Bavaro (1 case), and La Romana (1 case).

The Pan American Health Organization (PAHO) is working with the Ministry of Health in the Dominican Republic to ensure that intensive measures to interrupt transmission of malaria, including intensified surveillance and vector control, are being implemented in the Province of La Altagracia.

The Agency continues to collaborate with the US Centers for Disease Control and the Pan American Health Organization in the monitoring and reporting of new cases of malaria in returning travellers from the Dominican Republic.

Source: US Centers for Disease Control, TropNetEurop , Pan American Health Organization

Malaria is known to be endemic (i.e., constantly occurring) in rural areas of the Dominican Republic, with the highest risk in areas bordering Haiti. Resort areas are generally not risk areas. However, occasional outbreaks of malaria transmission can occur in these malaria-free areas due to the presence of the mosquito vector and the movement of people from the areas where transmission occurs.

The Dominican Republic reports approximately 1000 cases of malaria annually. This year, more than 2000 cases have been reported with an outbreak of cases occurring in previously malaria-free areas. This phenomena may be due to several factors including two recent hurricanes which have affected the island, an increase in the population of the mosquito vector (Anopheles) and the movement of many construction workers from rural areas into tourist areas.

In 1998, a localized outbreak of malaria occurred in a tourist area of eastern DR (Bavaro-Punta Cana). Although all malaria in the DR is due to P. falciparum , no drug resistance has been documented.

In consultation with the Malaria Sub-Committee of the Committee to Advise on Tropical Medicine and Travel (CATMAT), the Public Health Agency of Canada recommends the following for travellers to the DR at this time:

Recommendations

The Public Health Agency of Canada strongly recommends that you obtain an individual risk assessment with a travel medicine physician or your family physician to determine both your risk of exposure to malaria and your need for appropriate preventative anti-malarial treatment as determined by your travel itinerary and medical history.

Two important measures can help you prevent malaria infection: avoiding mosquito bites and using effective anti-malarial medications.

Personal Measures to Avoid Mosquitoes

Female Anopheles mosquitoes bite mainly during the evening and night. Using personal insect protective measures will reduce your risk of being bitten by these mosquitoes.

• stay in well-screened or completely enclosed, air-conditioned accommodation;
  
• sleep under insecticide-treated bed nets;
  
• wear clothing that reduces the amount of exposed skin; wear long-sleeved shirts (tightly weaved material, sleeves down, buttoned/zipped up, tucked into pants) and long pants (tucked into socks or footwear);
  
• light-coloured clothing may be less attractive to some mosquitoes and make mosquitoes more noticeable;
  
• use DEET-based products as repellents on exposed skin. The higher the concentration of DEET in the repellent formulation, the longer the duration of protection. However, this relation reaches a plateau at about 30% to 35%. DEET formulations that are "extended duration" (ED), such as polymers, are generally considered to provide longer protection times, and may be associated with less DEET absorption. Formulations over 30% are not currently available in Canada, although they are available internationally, including in the United States. It should be noted, however, that products sold outside Canada have not been evaluated by Health Canada. Most repellents containing "natural" products are effective for shorter durations than DEET and for this reason are not considered the preferred products for protecting against mosquito bites.
  
  Regulatory agencies in western nations may differ regarding the recommended maximum concentration and application rates of DEET, especially for children. The Committee to Advise on Tropical Medicine and Travel (CATMAT) is satisfied that, for travel outside of Canada where the risk of malaria outweighs the risk of any important adverse reaction to DEET, the threshold for use of DEET should be low.
  
  CATMAT recommends that concentrations of DEET up to 35% can be used by any age group.
  
  For children, alternative personal protective measures, such as mosquito nets treated with insecticide, should be the first line of defence, especially for infants less than 6 months of age. Portable mosquito nets, including self-standing nets, placed over a car seat, a crib, playpen, or stroller help protect against mosquitos. However, as a complement to the other methods of protection, the judicious use of DEET should be considered for children of any age. Recent medical literature from Canada suggests that DEET does not pose a significant or substantial extra risk to infants and children.
  
  DEET/sunscreen combination products are not generally recommended, because DEET can decrease the efficacy of sunscreens. As well, sunscreens should be used liberally and often while DEET should be used sparingly and only as often as required. If application of both is necessary, the Canadian Dermatology Association recommends that the sunscreen be applied first and allowed to penetrate the skin for 20 minutes, prior to applying DEET.

Antimalarial Medication (Prophylaxis)

Antimalarial medications decrease the risk of developing symptomatic malaria. However, they do not provide 100% protection against the disease. Your individual need for antimalarial medications should be discussed with your physician or travel medicine professional several weeks before travel.

If your physician or travel medicine clinic prescribes an antimalarial medication, it is important that you take it as directed in order to maximize the protective effect. Each drug has its own dosing regime that should be strictly followed. Because of the incubation period of the disease, these medications must be taken both before and after travel.

Important to Note

If you develop a fever within 3 months after returning from an area where malaria occurs, you should seek medical advice immediately. Be sure to inform your physician that you have visited an area where malaria occurs so that you can be tested without delay. Malaria must be ruled out by the examination of one or more blood films under a microscope.

For additional information on malaria:

• Visit the Public Health Agency of Canada's Disease Information Backgrounder on Malaria.
• The Committee to Advise on Tropical Medicine and Travel (CATMAT) produces evidence based statements and guidelines. For maps of malaria-endemic areas and other information about malaria, visit CATMAT's Canadian recommendations for the prevention and treatment of malaria among international travellers as published in the Canada Communicable Disease Report - Supplement (Vol. 30, June 2004).
• Malaria – Frequently Asked Questions