The minor role of pigs in outbreaks of foot‐and‐mouth disease of northern Thailand

Abstract

A study was undertaken in northern Thailand to examine the involvement of pigs in outbreaks of foot-and-mouth disease (FMD). Data were collected by surveying selected villages, by serological monitoring of pigs and by investigating outbreaks. Fifty-three of 58 villages (91%) surveyed reported that pigs did not develop FMD during the most recent outbreak. The source of 49/60 (82%) outbreaks was attributed to either recent purchases of infected cattle and buffalo or commingling of cattle and buffalo with stock from an infected neighbouring village. One of 60 villages (1.7%) reported that the source was introduced infected pigs. There was no association between the various hypothesised risk factors relating to the management of pigs and the frequency of FMD outbreaks in the survey. The percentage of seropositive pigs during 3 rounds of serological monitoring conducted at 6-monthly intervals in selected villages was 3.5%, 2.6% and 0%, respectively. No clinically affected pigs were observed in 11 outbreak investigations. It was concluded that pigs did not commonly become infected when there were outbreaks of FMD in village cattle and buffalo in northern Thailand. This was probably due to the pig feeding and housing practices employed by villagers that protected pigs from exposure to virus from infected cattle or buffalo, or their products.

Knowledge, attitudes and practices of smallholder farmers on foot and mouth disease control in two Cambodian provinces

“…With most farmers using the communal grazing method, the movement of large ruminants to communal grazing areas enables contact with animals from other locations, increasing the risk of contracting diseases, particularly FMD, as previously reported by other studies (Chamnanpood et al, 1995;Cleland et al, 1995), and recently reviewed by Blacksell et al (2019). During FMD outbreaks, confining and feeding cattle on cut grasses reduces the likelihood of infection, with this practice proposed to reduce the risk of spread of FMD virus by reducing the direct contact between healthy and infected animals (Cleland et al, 1996).…”

“…With most farmers using the communal grazing method, the movement of large ruminants to communal grazing areas enables contact with animals from other locations, increasing the risk of contracting diseases, particularly FMD, as previously reported by other studies (Chamnanpood et al., 1995; Cleland et al., 1995), and recently reviewed by Blacksell et al. (2019).…”

A review of the status of foot and mouth disease in South-East Asia and approaches to control and eradication

“…The World Reference Laboratory (WRL) for FMD in Pirbright in the United Kingdom (UK) provides information on the genetic relationships between field isolates submitted from member countries. There are a limited number of scientific publications on FMD epidemiology in South-East Asia, with most of the work arising from studies conducted in Thailand (2,3,4,5).…”

A history of FMD research and control programmes in Southeast Asia: lessons from the past informing the future

“…Interestingly, studies in Vietnam have demonstrated that persistently infected animals do not transmit the disease animals to naive animals [31]. In SEA, pigs have been reported as both refractory [32] and highly susceptible [5] to FMD infection, illustrating the important role of adaption and species susceptibility to different FMD strains such as the pig-adapted O/CHY topotype [33]. The role of small ruminants in the epidemiology of FMD in SEA is unclear which highlights the need for further studies to understand the function of all species for disease control or eradication.…”