Incidence and distribution of Foot-and-mouth disease in Asia, Africa and South America; combining expert opinion, official disease information and livestock populations to assist risk assessment
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Date
2008
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Publisher
Blackwell Verlag
Abstract
Risk assessment procedures frequently require quantitative data on the preva-
lence of the disease in question. Although most countries are members of the
World Organization for Animal Health (OIE), the importance attached to
foot-and-mouth disease (FMD) reporting or surveillance for infection varies
enormously between infected countries. There is a general consensus that FMD
outbreaks in endemic countries are greatly under-reported, to a degree related
either to the economic or the political development level of the country.
This exploratory study was first undertaken by FAO, but thereafter extended
and reviewed by the working group on FMD risk co-ordinated by the Euro-
pean Food Safety Authority (EFSA). The paper attempts to overcome the lack
of reporting through using expert opinion to extrapolate incidence indices
from countries considered to have ‘representative’ levels of FMD. These were
combined with livestock density distributions to provide maps of prevalence
indices, which were found to be highest in China (pigs), India (cattle), the
Near East (small ruminants) and the Sahel (small ruminants and cattle).
Similar patterns were found when weighted expert rankings of a range of
additional ranked disease parameters were also produced, and then combined
with susceptible animal densities to produce a weighted multi-species density.
Results suggest that the methods can provide useful information at both
national and sub-national resolution, even for countries for which quantitative
FMD data is currently unavailable: two of the regions identified provide little
or no data on a regular basis to the OIE and therefore may be overlooked if
the level of officially reported FMD is only used. As the estimated prevalences
are based on recent disease history and expert opinion, they are most likely to
be inaccurate where FMD incursions are infrequent as a result of the preventive
measures and geographical and trade isolation. This study, therefore, highlights
the need for specific detailed country risk assessments where livestock trade is
under consideration. Validating the approach including ground truthing, will
require collaboration between a number of agencies and institutions, in critical
countries, particularly those with high disease burdens that share borders or
trade livestock with currently FMD-free nations.
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Keywords
Foot-and-mouth disease, Global distribution, Risk assessment, Incidence