Comparative susceptibility of indigenous and improved pig breeds to Classical swine fever virus infection: Practical and epidemiological implications in a subsistence-based, developing country setting

Abstract

This study investigated the comparative susceptibility of indigenous Moo Laat and improved Large White/Landrace pig breeds to infection with classical swine fever virus (CSFV) under controlled conditions in the Lao People's Democratic Republic (Lao PDR). The Moo Laat (ML) and Large White/Landrace cross-breed (LWC) pigs were inoculated with a standard challenge strain designated Lao/Kham225 (infectivity titre of 10(2.75) TCID50/ml). The results demonstrated that both the native breed and an improved pig breed are fully susceptible to CSFV infection and the mortality rate is high. LWC pigs demonstrated lower (or shorter) survival times (50% survival time: 11 days), earlier and higher pyrexia and earlier onset of viraemia compared to ML pigs (50% survival time: 18 days). In the context of village-based pig production, the longer time from infection to death in native ML pigs means that incubating or early sick pigs are likely to be sold once an outbreak of CSF is recognized in a village. This increased longevity probably contributes to the maintenance and spread of disease in a population where generally the contact rate is low.

Comparative analyses of host responses upon infection with moderately virulent Classical swine fever virus in domestic pigs and wild boar

“…However, neither beneficial nor detrimental host reaction patterns have been defined up to know, and the influence of breed-related factors remains unclear. Yet, indications exist that breed and race may have a relevant impact on the severity of the disease [1,4-6]. To target this issue, the presented study was undertaken to compare host responses of different pig breeds upon infection with a recent moderately virulent CSFV strain.…”

“…Depner et al [1] showed that German landrace pigs were more severely affected than crossbred animals. Influence of breed was also seen when susceptibility was assessed in indigenous Moo Laat and improved Large White/Landrace [4]. In contrast, no differences were seen by Bunzenthal [10].…”

Classical Swine Fever—An Updated Review

“…Susceptible hosts are different members of the Suidae family, particularly domestic pigs ( Sus scrofa domesticus ) and European wild boar ( Sus scrofa scrofa ) [113,164]. Moreover, the susceptibility of common warthogs ( Phacochoerus africanus ) and bushpigs ( Potamochoerus larvatus ) was recently demonstrated [165].…”

Diagnosis of classical swine fever virus in a limited resource setting: The influence of pig breed on methodology and sample selection

“…A full description of the experimental protocol is given elsewhere (Blacksell et al, 2006). Briefly, two breeds of pigs, an indigenous Lao breed known locally as Moo Laat (ML) and Large White/Landrace crossbreed (LWC) pigs were inoculated via the subcutaneous route with 1 ml of a CSF virus designated Lao/Kham225 genotype 2.2 (Blacksell et al, 2004b(Blacksell et al, , 2005 with an infectivity titre of 10 2.75 TCID 50 .…”