Effectiveness and costs of interventions to reduce the within-farm Toxoplasma gondii seroprevalence on pig farms in the Netherlands

Dorien M Eppink,Manon Swanenburg,Henk J Wisselink,Joke W.B Van Der Giessen,Marcel A.P.M Van Asseldonk,Coen P.A Van Wagenberg,Inge M Krijger,Martijn Bouwknegt

doi:10.1186/s40813-021-00223-0

Abstract

BackgroundThe parasite Toxoplasma gondii (T. gondii) is recognized as one of the major foodborne pathogens with a high human disease burden. To control T. gondii infections in pigs, European Food Safety Agency (EFSA) advises serological testing of pigs and audits of pig farms to identify risk factors for T. gondii infection. In line with this approach, the aim of the current study was to assess the effectiveness and costs of intervention measures implemented to reduce the T. gondii seroprevalence on finishing pig farms in the Netherlands. A crossover clinical trial was conducted at five case farms were their own control and the cross-over moment was the implementation of interventions to reduce risk factors. Each of the case farms had a farm-specific intervention strategy with one principal intervention measure (neutering of cats, professional rodent control or covering food storage).ResultsAll finishing pig farms (n = 5) showed a reduction in T. gondii seroprevalence within one year of implementing the intervention strategy. Cat neutering (n = 3) and feed coverage (n = 1) showed statistically significant reductions in seroprevalence. Rodent control (n = 1) did not show a statistically significant reduction. The estimated reduction in seroprevalence in response to the neutering of cats and feed coverage were 67 and 96 %, respectively.ConclusionsOur work demonstrates that it is possible to reduce the within-farm T. gondii seroprevalence within one year after interventions were implemented to reduce T. gondii risk factors. This information is essential and encouraging for policy makers, food business operators, and farmers to implement in their risk assessment and to apply to food safety control systems.

Highlights

The parasite Toxoplasma gondii (T. gondii) is recognized as one of the major foodborne pathogens with a high human disease burden
Farm characteristics Nine farmers were approached for this study, each farm with an estimated within farm seroprevalence > 10 % and a minimum of six deliveries in the previous running year, i.e. the selection period
Taken together the results of all pigs from the five farms, 1,280 blood samples were analyzed during the two-year study period, of which 258 (20.2 %) tested positive for the presence of T. gondii antibodies

Summary

Introduction

The parasite Toxoplasma gondii (T. gondii) is recognized as one of the major foodborne pathogens with a high human disease burden. To control T. gondii infections in pigs, European Food Safety Agency (EFSA) advises serological testing of pigs and audits of pig farms to identify risk factors for T. gondii infection. In line with this approach, the aim of the current study was to assess the effectiveness and costs of intervention measures implemented to reduce the T. gondii seroprevalence on finishing pig farms in the Netherlands. Toxoplasma gondii (T. gondii) is an ubiquitous protozoan parasite capable of infecting virtually all warmblooded vertebrates throughout the world [1, 2] It is an obligate intracellular organism belonging to the coccidian family. In non-immunocompromised humans, a postnatal infection can cause ocular disease [3]

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