Evidence of Dengue Virus Infection in a German Couple Returning from Hawaii TomasJelinek, Gevhavd Doblev, and Hans Dieter ~ o t h d ~ ~

Dengue is an acute, mosquito-transmitted viral dis- ease characterized by fever, arthralgia, myalgia, rash, nau- sea, and vomiting and caused by any of four different serotypes of the virus (DEN-I, DEN-2, DEN-3, and DEN-4).’ The disease is endemic in most tropical areas of the world and has been reported in international travelers returning from such areas.*The incidence of epi- demic and endemic dengue has increased substantially in the Americas since 1977, and various epidemics have occurred.’-’

Case Report

A German couple, aged 37 and 36 years, presented to our outpatient clinic in December 1995 reporting an acute illness during their journey to Hawaii in Novem- ber 1995. Fever (up to 40°C), severe headache, myalgia, arthralgia, and epistaxis started in both tourists simulta- neously during their third week in Hawaii and lasted for 6 days. Symptoms were more severe in the husband.These symptoms receded spontaneously in both patients with- out treatment before their return to Germany, and gave way to residual malaise lasting for 3 weeks.

O n presentation 2 weeks after onset of symptoms, clinical examination was unobtrusive in both patients, and routine hematological and biochemical profiles were

Tomas Jelinek, MD, and Hans Dieter Nothdurfi, MD: University of Munich, Department of Infectious Diseases and Tropical Medicine, Munich, Germany; Gerhard Dablec Max von Pettenkofer Institute, Munich, Germany.

Reprint requests: Dr. Tomas Jelinek, University of Munich, Department of Infectious Diseases andTropical Medicine, Leopoldstr. 5, 80802 Munich, Germany.

JTravel Med 1998; 5:44-45.

within normal limits. The examination of blood speci- mens drawn during the first presentation and 3 weeks later by an iinmunofluorescence test (IFAT) (with anti- gen of Dengue 2, strain New Guinea, cultured in vero cells) showed significantly increasing titers of IgG anti- bodies against antigen of dengue virus and related fla- viviruses (Table 1). IgM antibodies were positive against dengue virus only in the husband (titer 1:40 on both examinations).The cultivation of virus was not attempted upon presentation of the patients 1 week after their acute symptoms had receded.

Aedes aegypti and Aedes albopictur mosquitoes are the principal vectors of dengue.’ These mosquitoes are well ?dapted to an urban environment.They breed in tires, cans, and water jars near human dwellings, and the females transmit dengue readily due to their predilection for human blood and habit of multiple, interrupted feed- ing.5 Both species are endemic in some states of the United States, but are not known to occur in Hawaii (D. Gubler, Centers for Disease Control, Atlanta, personal communication).

Both patients described here suffered from typical symptoms of dengue with a remarkably synchronous course.They had not traveled to any area commonly asso- ciated with arbovirus infections and reported several mosquito bites during their stay in Hawaii. They had received vaccinations against yellow fever 10 years and tick-borne encephalitis 3 months and 4 years, respectively, prior to this journey, and could not remember any pre- vious episode of arbovirus infection in their lives.The rise of antibodies in both patients after their convalescence supports the suspicion that the infection was actually acquired in Hawaii. Another possible explanation could be anonspecific re-activation of the vaccination against tick-borne encephalitis both patients had received, although such an occurrence seems an unlikely event 4 years after the original vaccination. The most favorable explanation for this episode is that both patients might have contracted what could be called “airport dengue”- an infection caused by the bite of a mosquito imported by plane from an Asian destination.

It would be worthwhile to watch for similar cases to confirm the possibility of dengue infection outside areas of established endemicity. Surveillance systems like Geo Sentinel might prove useful tools for such purposes.

44

J e l i n e k et a l . , D e n g u e I n f e c t i o n Impor ted f rom H a w a i i 45

Table 1 IgG-Antibody Titers in a German Couple after Acute Infection with Dengue Virus in Hawaii

Husband (3 7 y ) Wi,G (36 y)

Sperimen 1* Specimen 2+ Specimen I* Specimen 2+

Virus Aiztigen (Tlterj (Titer) (Titer) (Titer)

Dengue 1.1280 2560 West Nile 160 1280 Yellow fever 160 1280 Tick-borne encephalitis 160 1280 California encephalitis group 0 0 Sindbis 0 0

1280 160 80

160 0 0

*Blood drawn 2 weeks after onset and 1 week after receding of acute symptoms. Blood drawn 5 weeks after onset and 4 weeks after receding of acute symptoms.

References 3.

1. Rigau Perez JG, Gubler DJ,Vorndani AV, Clark GG. Dengue surveillance-United States, 1986-1992. M M W R CDC Surveil1 Summ 1994; 43:7-19.

M M W R Morb Mortal Wkly Rep 1995; 44:353-356.

4.

2. Anonymous. Imported dengue-United Statec, 1993-1994. 5.

Hayes EB, Gubler UJ. Dengue and dengue hemorrhagic fever. Pediatr Infect Uic J 1992;11:311-317. Anonymous. Imported dengue-United States, 1992. M M W R Morb Mortal Wkly Rep 1994; 43:97-99. Lifson A. Mosquitoes, models, and dengue. Lancet 1996; 347: 1201-1 202.

View of Shanghai from the top of the TVTower, Shanghai, P. R. C. Submitted by Charles D. Ericsson, MD.