House-to-house human movement drives dengue virus transmission

Abstract

Dengue is a mosquito-borne disease of growing global health importance. Prevention efforts focus on mosquito control, with limited success. New insights into the spatiotemporal drivers of dengue dynamics are needed to design improved disease-prevention strategies. Given the restricted range of movement of the primary mosquito vector, Aedes aegypti, local human movements may be an important driver of dengue virus (DENV) amplification and spread. Using contact-site cluster investigations in a case-control design, we demonstrate that, at an individual level, risk for human infection is defined by visits to places where contact with infected mosquitoes is likely, independent of distance from the home. Our data indicate that house-to-house human movements underlie spatial patterns of DENV incidence, causing marked heterogeneity in transmission rates. At a collective level, transmission appears to be shaped by social connections because routine movements among the same places, such as the homes of family and friends, are often similar for the infected individual and their contacts. Thus, routine, house-to-house human movements do play a key role in spread of this vector-borne pathogen at fine spatial scales. This finding has important implications for dengue prevention, challenging the appropriateness of current approaches to vector control. We argue that reexamination of existing paradigms regarding the spatiotemporal dynamics of DENV and other vectorborne pathogens, especially the importance of human movement, will lead to improvements in disease prevention.infectious disease | spatial epidemiology | arthropod-borne virus | emerging infections | disease ecology D engue is a mosquito-borne viral infection prevalent in the tropics and subtropics with an incidence and range that have increased substantially over the last three decades (1-4). The incidence of severe, life-threatening disease (dengue hemorrhagic fever or DHF) is also on the rise (5). Dengue virus (DENV) is caused by any of four closely related, but antigenically distinct and genetically diverse, virus serotypes (DENV-1, -2, -3, and -4), which are transmitted by day-biting, peridomestic Aedes mosquitoes, primarily Aedes aegypti (6). Incompletely understood immunological interactions among serotypes that can enhance disease severity (7-9) have hampered the development of effective, commercially available vaccines. A recent trial of a promising vaccine candidate demonstrated only partial (<33%) protection (10). Effective antiviral therapeutics are also not available. Thus, despite nearly a century of research, the only tools presently available to combat dengue target mosquito populations, mostly with insecticides and larval source reduction. In current practice, these tools are most often only partially effective (11). Although new vector control approaches are under development (12), innovations in dengue-control approaches are constrained by our limited understanding of virus-transmission dynamics and its drivers. In particular, the role of human movemen...

Lineage II of Southeast Asian/American DENV-2 is Associated with a Severe Dengue Outbreak in the Peruvian Amazon

“…One of the cohorts has been previously described and included 38 blocks distributed over two zones, whereas the second cohort included eight zones, with two blocks per zone. 46,47 If a participant was found to have a febrile illness, a standard questionnaire was used to obtain demographic and clinical information, and acute and convalescent blood samples were collected.…”

Calling in sick: impacts of fever on intra-urban human mobility

“…In total, that study involved 2444 participants aged 5 years or older living in two intensively studied neighbourhoods, Maynas and Tupac Amaru (electronic supplementary material, figure S1). This longitudinal cohort study has been described in full detail by Stoddard et al [25]. Salient details of that study include that febrile participants were identified by members of the field team who actively monitored for fever (defined as body temperature !388C) in each house, which was visited at least three times per week during the study period.…”

Temperature and population density determine reservoir regions of seasonal persistence in highland malaria

“…A better understanding of persistence would require, however, additional consideration of spatial variation in demographic and environmental factors at sufficiently high spatial and temporal resolution. Although among demographic factors, human mobility has recently attracted attention [5][6][7][8][9], the role of population density remains poorly understood in the population dynamics of malaria and other vector-transmitted diseases. In particular, larger numbers of hosts in mathematical models generally dilute the number of vector bites and in so doing also decrease transmission rates [10].…”