1 figure omitted
Malaria is caused by any of four Plasmodium parasites
carried by Anopheles mosquitoes and usually is transmitted
by the bite of an infective female Anopheles. In
rural areas of the Dominican Republic, P. falciparum malaria
is endemic, with the highest risk in the far western region of the country,
and prophylactic medication with chloroquine is recommended for incoming travelers.
Conversely, urban and resort areas in the Dominican Republic have been considered
nonmalarious, and prophylactic medication has not been recommended for persons
traveling to these areas.1 However, since November
2004, CDC has received reports of three malaria cases in U.S. travelers returning
from areas in La Altagracia and Duarte provinces previously considered nonmalarious.
An additional 14 cases of malaria in La Altagracia Province, in the far eastern
region of the country, have been reported in European and Canadian travelers.
This report describes three of these 17 malaria cases and summarizes the overall
investigation, which led to expansion of CDC recommendations for chloroquine
prophylaxis to include all of La Altagracia and Duarte provinces.
Case 1. During the third week of November 2004,
a woman aged 47 years was admitted to an intensive care unit (ICU) in the
United States with multisystem organ failure, including acute respiratory
distress syndrome and renal failure. She had a 6-day history of fever, chills,
abdominal pain, headache, nausea, and vomiting that began 24-36 hours after
returning from a 1-week vacation to a resort in Punta Cana in La Altagracia
Province. The patient had been examined twice by a health-care provider in
an outpatient setting and sent home. Two days before hospital admission, she
had jaundice. On admission, the patient had P. falciparum malaria on blood smear (35% parasitemia), anemia (hemoglobin: 10.4
g/dL [normal: 12-18 g/dL]), leukocytosis (white blood cell count: 35,000/μL
[normal: 5,000-10,000/μL]), severe thrombocytopenia (platelet count: 5,000/μL
[normal: 130,000-400,000/μL]), and was obtunded. The patient was started
on intravenous quinidine gluconate, and the parasitemia cleared in 2 days.
On the fifth day of hospitalization, the quinidine was discontinued, and the
patient was placed on doxycycline. The patient underwent hemodialysis for
renal failure; she improved and was discharged to a rehabilitation center,
where she remained as of December 30, 2004. Her husband reported that they
had stayed at an all-inclusive resort in Punta Cana during their entire week
in the Dominican Republic and did not travel to other areas. In addition,
the patient had not traveled to any other malarious areas nor received any
blood transfusions during the preceding year.
Case 2. In late November, a man aged 71 years
visited an emergency department in Canada 10 days after returning home from
a week at a resort in Punta Cana and after 4 days of fever, myalgias, and
malaise. Viral infection was diagnosed, and the man was discharged home. The
next day, he saw his family doctor, who also diagnosed a viral illness. The
following day, the patient’s condition deteriorated substantially, and
he was admitted to the hospital with hypotension, hypoxia, acute renal failure,
and respiratory failure requiring mechanical ventilation. Two days after admission,
the patient had a blood smear that demonstrated a 9% P.
falciparum parasitemia. He was treated with intravenous quinidine and
doxycycline and underwent hemodialysis. The patient reported taking a day
trip to Santo Domingo while in the Dominican Republic but reported no other
travel. During the preceding year, he had not traveled to any other malarious
areas nor received any blood transfusions. As of December 30, the patient
Case 3. In late November, a man aged 39 years
was admitted to an ICU in Canada 12 days after returning home from a resort
in Punta Cana, where he had stayed for 2 weeks. The patient reported having
fevers and chills for 9 days and later had jaundice. One day after admission,
he had a blood smear revealing 2% P. falciparum parasitemia
and was treated with chloroquine and quinine. The patient was anemic and had
acute respiratory distress syndrome, acute renal failure, and cerebral malaria;
he underwent exchange transfusion. During the preceding year, the patient
had not traveled to any other malarious areas nor received any blood transfusions.
As of December 30, the patient remained hospitalized.
After receiving reports of malaria in two U.S. travelers to the Dominican
Republic, CDC contacted the Pan American Health Organization, World Health
Organization, and Ministry of Health (MoH) in the Dominican Republic, which
initiated investigations. Seventeen patients (i.e., three from the United
States, six from Canada, and eight from European countries) were identified*; P. falciparum malaria was confirmed in all of them. Sixteen
of the patients had traveled to Punta Cana resorts in La Altagracia Province
and one to San Francisco de Macorís in Duarte Province. Sixteen returned
home during November 3-16, and one returned December 20; all were admitted
to hospitals, and six required treatment in ICUs. As of December 30, no deaths
had been reported; three patients remained hospitalized. Seven of the patients
confirmed that they had not traveled to any other malarious areas nor received
any blood transfusions during the preceding year.
On November 24, CDC expanded its recommendations for chloroquine prophylaxis
for travelers to the Dominican Republic to include all of La Altagracia and
Duarte provinces, in addition to rural areas countrywide.2 The
revised recommendations advise clinicians and travelers about the expanded
malaria risk area so that any febrile persons who have visited these areas
will receive prompt diagnosis and treatment to avoid severe complications.
Major networks of blood collection agencies and the Food and Drug Administration
also were contacted. Similar alerts were issued by health officials in Europe
and by the Public Health Agency of Canada.
The MoH investigation included active case detection and entomologic
investigations in La Altagracia and Duarte provinces. In Duarte Province,
officials confirmed that no other cases had been reported during 2003-2004.
Nonetheless, MoH is taking precautionary measures, including enhanced surveillance.
In La Altagracia Province, MoH surveillance data have identified an increase
in cases of malaria beginning in November 2004 among migrant workers in the
Bavaro Zone, 10 miles from the Punta Cana resort area. MoH intensified control
measures in the Bavaro Zone, which include (1) presumptive treatment of all
construction and hotel workers by using directly observed therapy with chloroquine
and primaquine, and (2) mosquito control through residual and spatial insecticide
spraying and application of larvicide to suspected breeding sites. Measures
instituted in the Punta Cana resort area include intensified surveillance
and larvicide application.
C Kay, MD, D Patrick, MD, British Columbia Centre for Disease Control,
Vancouver; J Keystone, MD, Univ Health Network/GeoSentinel, Toronto; M Bodie-Collins,
Public Health Agency of Canada. C Riera, MD, Pan American Health Organization;
J Puello, MD, Ministry of Health, Dominican Republic. T Jelinek, MD, Berlin
Institute of Tropical Medicine, Germany. D Freedman, MD, GeoSentinel Global
Surveillance Network of the International Society of Travel Medicine, Stone
Mountain, Georgia. P Kozarsky, MD, C Reed, MD, Div of Global Migration and
Quarantine; M Parise, MD, P Nguyen-Dinh, MD, R Steketee, MD, Div of Parasitic
Diseases, National Center for Infectious Diseases; M Eliades, MD, EIS Officer,
This report describes an outbreak of malaria in areas in the Dominican
Republic previously thought to be nonmalarious. P. falciparum is the only malaria parasite in the Dominican Republic and has remained
susceptible to chloroquine. Because P. falciparum malaria
can be rapidly fatal, travelers should be aware of risk areas so that they
can take appropriate preventive measures; clinicians should consider malaria
in their diagnosis and treatment of febrile illness in travelers. Malaria
can be prevented by taking an antimalarial drug and by preventing mosquito
bites. Chloroquine is the recommended drug for malaria prevention for persons
traveling to the Dominican Republic and is highly efficacious and well tolerated
by most travelers. To prevent mosquito bites, travelers should use insect
repellent containing up to 50% DEET and wear long-sleeved clothing; if not
staying in screened or air-conditioned housing, they should sleep under a
net, preferably one treated with insecticide. Rapid intervention is crucial
for ill travelers with suspected malaria.3 In
nearly all cases in this outbreak, delays in diagnosis and treatment occurred;
in certain cases, delays contributed to serious illness.
During July 1999–March 2000, a previous outbreak in the Dominican
Republic occurred among European travelers to Punta Cana, principally in the
Bavaro Zone. Factors identified as contributing to that outbreak were (1)
the increased breeding of A. albimanus mosquitoes,
the predominant malaria vector in the Dominican Republic, in the wake of Hurricanes
Mitch and George and (2) malaria-infected migrant workers. In 1999, approximately
3,000 malaria cases were reported in the Dominican Republic, a 50% increase
over the number of cases in 1998.4 During the
1999-2000 outbreak, CDC travel recommendations were temporarily expanded to
recommend chloroquine prophylaxis for all areas in La Altagracia Province;
this recommendation was rescinded 2 months later after MoH increased surveillance
and controlled the outbreak.
In September 2004, Hurricane Jeanne struck the Dominican Republic. The
east coast, including Punta Cana and the Bavaro Zone, received heavy rains
and flooding, which might have resulted in increased breeding of mosquitoes.
In addition, construction in Punta Cana and the Bavaro Zone has brought in
many migrant workers from areas where malaria is endemic. The ongoing MoH
investigation will attempt to determine whether these factors have contributed
to the recent increased transmission. MoH surveillance data indicate that,
on average, approximately 1,500-2,500 malaria cases are reported annually
in the Dominican Republic; in 2004, a total of 2,012 cases had been reported
Effective surveillance systems and rapid communication among surveillance
networks are crucial to detecting cases of malaria and intervening in areas
that are usually nonmalarious. During this outbreak, rapid communication among
surveillance networks in North America, Europe, and the Caribbean led to prompt
diagnoses and timely public health interventions to prevent additional cases
among residents of and travelers to the Dominican Republic.
*The first U.S. patient was reported through the Emerging Infections
Network, a provider-based sentinel network developed by the Infectious Disease
Society of America. The other two U.S. patients were reported through the
CDC Malaria Hotline. The Public Health Agency of Canada, the GeoSentinel Network,
and the European Network on Imported Infectious Disease Surveillance reported
six cases in travelers from Canada and eight cases in travelers from Europe.
Transmission of Malaria in Resort Areas—Dominican Republic, 2004. JAMA. 2005;293(6):671-672. doi:10.1001/jama.293.6.671