Probable importation of dengue virus type 4 to Angola from Brazil

Incidence of dengue fever in Israeli travelers 2008-2019

BACKGROUND

. Dengue virus (DENV) is a frequent travel-related infection, but longitudinal data on its incidence is limited. We aimed to study temporal trends of travel-related DENV burden and its geographical sources.

METHODS

. All cases of laboratory-confirmed DENV infection diagnosed at the Central Virology Laboratory of the Israeli Ministry of Health during 2008-2019 were evaluated. Numbers of Israeli tourist-entries to DENV endemic countries were available from the UN World Tourist Organization (UNWTO) database. DENV attack rates were calculated as cases per 100,000 traveler-entries. In addition, for Thailand and India incidence rates were calculated, using the average duration of stay reported in diagnosed DENV cases.

RESULTS

. During 2008-2019, 425 Israeli travelers were diagnosed with DENV: 80.3%, 12.8% and 6.9% were acquired in Asia, America and Africa respectively. The average global DENV attack rate increased from 2.5 cases per 100,000 tourist-entries in 2008 to 10.7 cases per 100,000 tourist-entries in 2019. Region-specific DENV attack rates were 4.4, 3.2 and 2.1 cases per 100,000 tourist-entries to Asia, Africa, and America respectively. The highest number of DENV cases were reported from Thailand and India; DENV incidence rates increased from 94.5 to 142.2 cases per 100,000 travel-years, and from 49.3 to 90.4 cases per 100,000 travel-years for Thailand and India respectively.

CONCLUSION

. Among Israeli travelers, worldwide DENV attack-rates have quadrupled during 2008-2019, reflecting both a growing DENV burden in Asia, but also the emergence of Africa as an important source of DENV. The need to protect travelers through vaccination remains urgent.

Underrecognition of Dengue during 2013 Epidemic in Luanda, Angola

Case detection should be improved by instituting routine laboratory-based surveillance for acute febrile illnesses in Africa.

Dengue in Angola

During the 2013 dengue epidemic in Luanda, Angola, 811 dengue rapid diagnostic test–positive cases were reported to the Ministry of Health. To better understand the magnitude of the epidemic and identify risk factors for dengue virus (DENV) infection, we conducted cluster surveys around households of case-patients and randomly selected households 6 weeks after the peak of the epidemic. Of 173 case cluster participants, 16 (9%) exhibited evidence of recent DENV infection. Of 247 random cluster participants, 25 (10%) had evidence of recent DENV infection. Of 13 recently infected participants who had a recent febrile illness, 7 (54%) had sought medical care, and 1 (14%) was hospitalized with symptoms consistent with severe dengue; however, none received a diagnosis of dengue. Behavior associated with protection from DENV infection included recent use of mosquito repellent or a bed net. These findings suggest that the 2013 dengue epidemic was larger than indicated by passive surveillance data.