Imported Plasmodium vivax malaria: demographic and clinical features in nonimmune travelers.
BACKGROUND
Imported malaria is an important problem in nonendemic countries due to increasing travel to and immigration from malaria-endemic countries. Plasmodium vivax malaria is relatively common in travelers but there are few published data regarding the outcome of P. vivax malaria in this group.


METHODS
We analyzed 209 cases of P. vivax malaria that were reported to the GeoSentinel network and the VIDS database, Royal Melbourne Hospital. Analyses were performed on data including demographics, pretravel encounter, antimalarial prophylaxis, exposure history, type of travel, countries of recent and past travel, clinical presentation, treatment, outcome and final diagnoses.


RESULTS
The majority of patients were travelers (61%), followed by expatriates (13%) and recent immigrants or foreign visitors (12%). Recent travel to Oceania, sub-Saharan Africa, and South and Central America was significantly more likely to be associated with P. vivax malaria than travel to all other regions. The clinical presentation of P. vivax malaria acquired in the Pacific region is indistinguishable from infection with P. falciparum. The use of chloroquine prophylaxis did not prolong the incubation period. Relapse of infection was not infrequent, and the only significant predictor of relapse was travel to Papua New Guinea (PNG), regardless of primaquine dose. Travelers returning from PNG were eight times more likely to relapse after primaquine treatment compared to travelers with P. vivax malaria acquired elsewhere.


CONCLUSIONS
We have presented details of the epidemiology, clinical presentation and management of infection with P. vivax malaria in travelers. P. vivax malaria is an important cause of morbidity in travelers, and relapse following primaquine treatment is especially problematic with P. vivax malaria acquired in PNG.
Elliott
Julian H
JH
Victorian Infectious Diseases Service, Royal Melbourne Hospital, Victoria, Australia.
O'Brien
Daniel
D
Leder
Karin
K
Kitchener
Scott
S
Schwartz
Eli
E
Weld
Leisa
L
Brown
Graham V
GV
Kain
Kevin C
KC
Torresi
Joseph
J
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D003906:Developing Countries; D018562:Disease Transmission, Infectious / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D016780:Malaria, Vivax / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control / Q000635:transmission*; D008297:Male; D008875:Middle Aged; D010966:Plasmodium vivax; D014195:Travel; D014739:Victoria / Q000453:epidemiology