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

Abstract

Pathogens inflict a wide variety of disease manifestations on their hosts, yet the impacts of disease on the behaviour of infected hosts are rarely studied empirically and are seldom accounted for in mathematical models of transmission dynamics. We explored the potential impacts of one of the most common disease manifestations, fever, on a key determinant of pathogen transmission, host mobility, in residents of the Amazonian city of Iquitos, Peru. We did so by comparing two groups of febrile individuals (denguepositive and dengue-negative) with an afebrile control group. A retrospective, semi-structured interview allowed us to quantify multiple aspects of mobility during the two-week period preceding each interview. We fitted nested models of each aspect of mobility to data from interviews and compared models using likelihood ratio tests to determine whether there were statistically distinguishable differences in mobility attributable to fever or its aetiology. Compared with afebrile individuals, febrile study participants spent more time at home, visited fewer locations, and, in some cases, visited locations closer to home and spent less time at certain types of locations. These multifaceted impacts are consistent with the possibility that diseasemediated changes in host mobility generate dynamic and complex changes in host contact network structure.

Contributions from the silent majority dominate dengue virus transmission

“…Acquiring this kind of empirical data is complicated by the difficulty of identifying people in these classes when they are viremic and the absence of diagnostic tools that reliably distinguish 2° from post-2° infections [ 45 ]. Moreover, people with symptomatic infections may experience impaired mobility [ 46 ] or otherwise modified interactions with mosquitoes, the impacts of which on net transmission are presently not well understood. Resolving these uncertainties and identifying effective strategies for mitigating the contributions of all infections, apparent or not, to DENV transmission will require comprehensive studies that combine field work and modeling to address the coupled nature of multiple transmission heterogeneities [ 33 ] (see S1 Text for a comprehensive discussion of additional limitations and research needs).…”

Dengue seroprevalence in a cohort of schoolchildren and their siblings in Yucatan, Mexico (2015-2016)

“…Dengue is a major public health problem in Latin America due to the increasing trend of cases, the vast urban areas affected, and the complexity of controlling a vector that has adapted to human dwellings in tropical and subtropical urban contexts [ 1 ]. Accurate estimates of the burden of dengue [ 2 ] are difficult because of the high proportion of asymptomatic infections, the syndromic nature of the clinical spectrum that allows for misdiagnosis with other viral infections [ 3 ], the limited capacities of the surveillance systems, and the low demand for health services by affected populations [ 4 – 6 ]. Transmission of the four dengue serotypes in endemic countries is heterogeneous with respect to the age groups affected, the seasonality, and the intensity and severity of epidemics[ 7 ].…”

Sickness‐induced lethargy can increase host contact rates and pathogen spread in water‐limited landscapes

“…First, the social context and reactions of uninfected individuals can change SIL and can even result in an increase in the contact rates for infectious individuals (Bouwman & Hawley, 2010;Lopes, 2014;Lopes et al, 2012). Second, it has been observed that sickness-related changes in mobility patterns can have complex effects on space use patterns in humans and therefore impact contact rates in complicated ways (Perkins et al, 2016).…”