Changing spatial epidemiology of pertussis in continental USA

Abstract

Prediction and control of the geographical spread of emerging pathogens has become a central public health issue. Because these infectious diseases are by definition novel, there are few data to characterize their dynamics. One possible solution to this problem is to apply lessons learnt from analyses of historical data on familiar and epidemiologically similar pathogens. However, the portability of the spatial ecology of an infectious disease in a different epoch to other infections remains unexamined. Here, we study this issue by taking advantage of the recent re-emergence of pertussis in the United States to compare its spatial transmission dynamics throughout the 1950s with the past decade. We report 4-year waves, sweeping across the continent in the 1950s. These waves are shown to emanate from highly synchronous foci in the northwest and northeast coasts. In contrast, the recent resurgence of the disease is characterized by 5.5-year epidemics with no particular spatial structure. We interpret this to be the result of dramatic changes in patterns of human movement over the second half of the last century, together with changing age distribution of pertussis. We conclude that extrapolation regarding the spatial spread of contemporaneous pathogens based on analyses of historical incidence may be potentially very misleading.

Region-wide synchrony and traveling waves of dengue across eight countries in Southeast Asia

“…Wavelet transforms are appropriate to characterize nonstationary signals with multiple periodicities, such as dengue IRs (6). We used a Morlet wavelet with a nondimensional frequency ω 0 = 6 as used previously (8,30). This wavelet is complex, enabling the extraction of phase angles to study epidemic timing.…”

“…Wavelet Transforms. We used wavelet methods to decompose reported dengue IRs into multiannual and annual cycles as described previously (2,8,9,30,31). Wavelet transforms are appropriate to characterize nonstationary signals with multiple periodicities, such as dengue IRs (6).…”

“…To better understand the spatiotemporal dynamics of large epidemics, previous studies used various time series decomposition methods to isolate multiannual oscillations from background annual cycles and higher frequency noise. For example, previous work on disease spread focused on the 1.5-3 y cycle for measles (2), the 3.5-4.5 and 5-6 y cycles for pertussis (8), and the 2-3 y (9, 10) and 3-4 y cycles (6) for dengue.…”

Is the current pertussis incidence only the results of testing? A spatial and space-time analysis of pertussis surveillance data using cluster detection methods and geographically weighted regression modelling

“…Despite previous findings that pertussis is highly heterogeneously distributed in space as well as in space-time [30,31], a substantial amount of current surveillance activities on pertussis is still restricted to a temporal analysis only [7,28,29,32], masking important regional variations and thus complicating an effective public health response.…”

Spatial structure, host heterogeneity and parasite virulence: implications for vaccine‐driven evolution

“…), foot‐and‐mouth diseases in cattle (Keeling et al . ), or pertussis in humans (Choisy & Rohani ). There is increasing evidence that disease spread is affected by changing patterns of mobility in hosts (e.g.…”