Patterns of spread and persistence of foot-and-mouth disease types A, O and Asia-1 in Turkey: a meta-population approach

Abstract

Despite significant control efforts, foot-and-mouth disease (FMD) persists in Turkey, and new strains of serotypes A, O and Asia-1 are periodically reported to enter the country from the east. The status of FMD in Turkey is important regionally because the country forms a natural bridge between Asia where the disease is endemic, and Europe which has disease-free status. This study analysed spatial and temporal patterns of FMD occurrence in Turkey to explore factors associated with the disease's persistence and spread. Annual records of FMD distribution in Turkish provinces throughout 1990-2002, grouped by serotype (O, A and Asia 1), were analysed using geostatistical techniques to explore their spatial and temporal patterns. A meta-population model was used to test how disease status, expressed in terms of presence/absence, extinction, and colonization, and measured at the province level throughout the periods 1990-1996 and 1997 2002, could be predicted using province-level data on: ruminant livestock numbers; meat production-demand discrepancy (as a surrogate measure of animal and animal products marketing, i.e. long-distance contagion through the traffic of mainly live animals to urban centres); and the disease prevalence distribution as recorded for the previous year. A drastic overall reduction in FMD occurrence was observed from the period 1990-1996 to 1997-2002 when the disease was shown to retract into persistence islands. FMD occurrence was associated with host abundance, short distance contagion from adjacent provinces, and meat production-demand discrepancies. With FMD retracting into identified provinces, a shift in predictors of FMD occurrence was observed with a lower contribution of short-distance contagion, and a relatively higher association with meat production-demand discrepancies leading to live animal transport over long distances, and hence presenting opportunities for identifying critical-control points. The pattern of persistence differed according to serotype groups and is discussed in relation to their differential affinity to cattle and small ruminant hosts.

Some Challenges to Progressive Control of Foot and Mouth Disease in Pakistan - Findings of a Pilot Survey

“…The animal vehicles transport diseased animals and are rarely disinfected. Theoretically, an effective contact is possible in communal grazing pastures (Admassu, ; Dukpa et al., ), routes in villages on which livestock move (Chakrabarti, ), watering points (Bronsvoort et al., ; Ghoneim et al., ) and animal vehicles (Gilbert et al., ; Schijven et al., ).…”

The Long Haul: Risks Associated With Livestock Transport

“…25 An analysis of spatial and temporal patterns of FMD occurrence in Turkey, historically an important bridge between the endemic regions in Asia and disease-free Europe, showed a shift of predictors over the study period (1990-2002) away from short-distance spread between neighboring provinces toward large jumps ascribed to live animal transport over long distances. 26 Although the origin of the 2001 British FMD outbreak was blamed on the illegal importation of contaminated meat, 27 the subsequent explosive spread within the country was, according to the World Organization for Animal Health, "mainly attributed to the movement of subclinically infected animals, principally of sheep, and by contact with contaminated vehicles used for the transportation of these animals." 22 A 1997 outbreak of classic swine fever in the Netherlands that spread to Italy, Spain, and Belgium was similarly linked to transport vehicles.…”

A Flexible Spatial Framework for Modeling Spread of Pathogens in Animals with Biosurveillance and Disease Control Applications

“…The framework we outline here builds upon and extends existing work to model spatial spread of animal disease [14][15][16][17][18][19][20]. Our work highlights the important and interacting roles of geography, and the spatial aspects of host diversity, host distribution, long and short distance movement, human-livestock interactions, and possible interventions.…”