Gert van der Hoek
In Memoriam - Editor, Senior Moderator
Q fever transmission to humans and local environmental conditions
Summary
The size of the Q fever outbreaks in 2007, 2008 and 2009 in the Netherlands suggests that
transmission to humans took place through environmental contamination or multiple pointsource
contamination sites, rather than from direct contact with animals.
Conclusive evidence
on environmental factors is still lacking and a number of dairy goat farms outside the high
incidence areas had major Q fever problems without any human cases in the surroundings. This
study assessed whether these discrepancies in transmission to humans of Q fever between the
different infected farms can be explained by environmental local conditions. Environmental
datasets were gathered on soil texture, land use, soil moisture and climate. The strongest
correlation was found with vegetation density (NDVI) and average groundwater conditions
which are strongly related to the soil moisture regime.
The results confirm that it is very likely
that these two environmental factors determine the transmission of Q fever from an infected
source to humans. Further investigation is recommended to assess how the spatial distribution
around the point source of these factors controls the transmission to humans of Q fever.
More: http://www.rivm.nl/cib/binaries/Q-fever transmission_tcm92-66769.pdf
Summary
The size of the Q fever outbreaks in 2007, 2008 and 2009 in the Netherlands suggests that
transmission to humans took place through environmental contamination or multiple pointsource
contamination sites, rather than from direct contact with animals.
Conclusive evidence
on environmental factors is still lacking and a number of dairy goat farms outside the high
incidence areas had major Q fever problems without any human cases in the surroundings. This
study assessed whether these discrepancies in transmission to humans of Q fever between the
different infected farms can be explained by environmental local conditions. Environmental
datasets were gathered on soil texture, land use, soil moisture and climate. The strongest
correlation was found with vegetation density (NDVI) and average groundwater conditions
which are strongly related to the soil moisture regime.
The results confirm that it is very likely
that these two environmental factors determine the transmission of Q fever from an infected
source to humans. Further investigation is recommended to assess how the spatial distribution
around the point source of these factors controls the transmission to humans of Q fever.
More: http://www.rivm.nl/cib/binaries/Q-fever transmission_tcm92-66769.pdf