A qualitative risk assessment indicates moderate risk of foot‐and‐mouth disease outbreak in cattle in the lower Okavango Delta because of interaction with buffaloes

Abstract

Foot-and-mouth disease (FMD) was first documented in domestic stock in Botswana in the early 1930s and since then the country opted for eradication of FMD from all her livestock-rearing areas. A multipronged control strategy was adopted along the pathway towards eradication that initially included strategic apthisation of cloven-hooved domestic stock up to 1964, movement restriction through cordon fences and quarantine system from the 1950s, and vaccination using readily available commercial vaccines from the mid-1960s, to date. This has resulted in 78% of the country's land area being officially declared and recognized by the World Organisation for Animal Health (OIE) as FMD free without vaccination. However, the disease has remained endemic in the northern parts of the country, owing largely to co-existence of livestock and wildlife. We applied a qualitative risk analysis method in our study to assess the risk of FMD outbreak in zone 2 because of interaction between cattle and buffalo across a man-made physical barrier, southern buffalo fence, in the north of the country. The assessed risk was rated 'moderate' with moderate level of uncertainty, meaning assessment of mitigation options should be done before authorising import of cattle and cattle product from zone 2. Because of cost escalation associated with FMD controls, particularly zoning with cordon fences in the face of relentless trampling by elephants, we concluded that there is a need to revise the national goal of country-wide eradication of FMD in livestock rearing areas to a more achievable outcome for zone 2. We recommend adoption of husbandry management practices and marketing approaches that recognizes co-existence of cattle and wildlife in zone 2 as an exception to the rest of the country. Such an approach should be rooted not on geographic occurrence of FMD nor separation of the two species but on food product safety guarantees along the value chain, and we believe this to be critical for sustainability of FMD management and livelihoods in zone 2.

A review of qualitative risk assessment in animal health: Suggestions for best practice

“…Published matrices using a multiplicative risk framework varied in the RAs reviewed here. One of the most commonly used adheres to the principle that the product of two probabilities is always equal to the lowest probability ( Table 3 ) ( 6 , 9 , 30 , 40 , 42 , 46 ). This matrix defines a likelihood estimate for any binary combination of conditional events but does not allow for the product of multiple conditional probabilities to be lower than the lowest value of the individual probabilities.…”

“…The use of expert opinion was described by some authors to reduce the uncertainty surrounding parameters where data were scarce ( 7 , 30 , 39 , 41 , 42 , 52 ). Some studies used workshops involving experts from a range of relevant backgrounds to confirm risk parameters, risk pathways and numerical weightings for risk factors reaching a final consensus of agreement ( 7 , 52 ).…”