Determinants of the geographic distribution of Puumala virus and Lyme borreliosis infections in Belgium.
BACKGROUND
Vector-borne and zoonotic diseases generally display clear spatial patterns due to different space-dependent factors. Land cover and land use influence disease transmission by controlling both the spatial distribution of vectors or hosts, and the probability of contact with susceptible human populations. The objective of this study was to combine environmental and socio-economic factors to explain the spatial distribution of two emerging human diseases in Belgium, Puumala virus (PUUV) and Lyme borreliosis. Municipalities were taken as units of analysis.


RESULTS
Negative binomial regressions including a correction for spatial endogeneity show that the spatial distribution of PUUV and Lyme borreliosis infections are associated with a combination of factors linked to the vector and host populations, to human behaviours, and to landscape attributes. Both diseases are associated with the presence of forests, which are the preferred habitat for vector or host populations. The PUUV infection risk is higher in remote forest areas, where the level of urbanisation is low, and among low-income populations. The Lyme borreliosis transmission risk is higher in mixed landscapes with forests and spatially dispersed houses, mostly in wealthy peri-urban areas. The spatial dependence resulting from a combination of endogenous and exogenous processes could be accounted for in the model on PUUV but not for Lyme borreliosis.


CONCLUSIONS
A large part of the spatial variation in disease risk can be explained by environmental and socio-economic factors. The two diseases not only are most prevalent in different regions but also affect different groups of people. Combining these two criteria may increase the efficiency of information campaigns through appropriate targeting.
Linard
Catherine
C
Department of Geography, Université Catholique de Louvain, Louvain-la-Neuve, Belgium. linard@geog.ucl.ac.be
Lamarque
Pénélope
P
Heyman
Paul
P
Ducoffre
Geneviève
G
Luyasu
Victor
V
Tersago
Katrien
K
Vanwambeke
Sophie O
SO
Lambin
Eric F
EF
D000818:Animals; D001096:Arachnid Vectors; D001530:Belgium / Q000453:epidemiology; D025065:Borrelia burgdorferi; D021821:Communicable Diseases, Emerging / Q000453:epidemiology*; D003710:Demography; D004777:Environment; D006480:Hemorrhagic Fever with Renal Syndrome / Q000453:epidemiology*; D006801:Humans; D016014:Linear Models; D008193:Lyme Disease / Q000453:epidemiology*; D015999:Multivariate Analysis; D016012:Poisson Distribution; D029262:Puumala virus; D012309:Risk-Taking; D012959:Socioeconomic Factors; D019371:Topography, Medical; D015047:Zoonoses / Q000453:epidemiology