Antimicrobial resistance at the livestock-human interface: implications for Veterinary Services.

The emergence of antimicrobial resistance (AMR) is a major global public health issue, but it also jeopardises the effectiveness of antimicrobials as a means of curing infections in animals that threaten their health, welfare and productivity. Several reports show that infections in humans caused by antimicrobial-resistant pathogens may be linked to antimicrobial use (AMU) and AMR in food-producing animals; however, to what extent this happens is unknown. Use of antimicrobials drives the emergence of AMR, therefore, their extensive over-use and misuse in livestock is of concern. Robust AMU and AMR data are important to monitor the progress of interventions aiming to reduce AMR in the livestock sector. However, not all countries have complete data on antibiotic sales or use, so our current knowledge of global AMU is primarily based on modelling estimates. Antimicrobial resistance prevalence data are limited, particularly in low- and middle-income countries, but in some high-income regions fairly robust data are available. It should also be noted that monitoring guidelines and protocols are available to provide globally harmonised AMR data. Using antimicrobials rationally and not using them for disease prevention purposes is key to reducing AMU. To ensure that these drugs are used appropriately we must ensure that: a) veterinary services are accessible and affordable for farmers; b) antibiotics are only sold on prescription; c) veterinarians earn no revenue linked to the sale or prescription of antibiotics; d) veterinarians have substantial skills in preventive medicine (good animal husbandry, efficient biosecurity and vaccinology); and e) the benefits of preventive measures must appeal to farmers so that they are willing to pay for them.

L'émergence de la résistance aux agents antimicrobiens (RAM) constitue un problème majeur de santé publique à l'échelle mondiale, qui compromet également l'efficacité des agents antimicrobiens utilisés chez les animaux pour traiter les infections menaçant leur santé, leur bien-être et leur productivité. Plusieurs rapports montrent que les infections humaines par des agents pathogènes résistants aux agents antimicrobiens sont probablement liées à l'utilisation d'agents antimicrobiens (UAM) et à la RAM chez les animaux servant à la production de denrées alimentaires ; toutefois, on ignore la portée exacte de ce phénomène. L'utilisation d'agents antimicrobiens étant à l'origine de l'émergence de la RAM, l'utilisation excessive ou le mauvais usage de ces produits chez les animaux d'élevage sont des sujets de préoccupation. Il est important de disposer de données solides sur l'UAM et la RAM afin de suivre les progrès des interventions visant à réduire la RAM dans le secteur de l'élevage. Plusieurs pays ont des données incomplètes sur les ventes ou l'utilisation d'antibiotiques au niveau national et nos connaissances actuelles sur l'UAM à l'échelle mondiale proviennent principalement d'estimations basées sur des modélisations. Les données sur la prévalence de la résistance aux agents antimicrobiens sont souvent éparses, en particulier dans les pays à revenu faible ou intermédiaire tandis que dans d'autres régions à revenu élevé, les données disponibles sont assez solides. Il convient à cet égard de signaler l'existence de lignes directrices et de protocoles de surveillance permettant de fournir des données harmonisées sur la RAM à l'échelle mondiale. Pour réduire l'UAM, il est essentiel d'appliquer des méthodes de prévention des maladies qui ne fassent pas appel aux agents antimicrobiens, et de n'utiliser ces derniers qu'en suivant des principes rationnels. Cela suppose de faire en sorte que : a) les services vétérinaires soient accessibles et abordables pour les éleveurs ; b) les antibiotiques ne soient vendus que sur ordonnance ; c) les vétérinaires ne tirent pas de revenus de la vente ou de la prescription d'antibiotiques ; d) les vétérinaires praticiens soient dotés de compétences solides en médecine préventive, y compris concernant les bonnes pratiques d'élevage, les mesures efficaces de biosécurité et la vaccinologie ; e) la valeur ajoutée de ces mesures soit bien perçue par les éleveurs afin qu'ils soient disposés à payer pour ces services.

La aparición de resistencias a los antimicrobianos no solo supone un importante problema de salud pública mundial, sino que también puede restar eficacia a los antimicrobianos para curar infecciones que amenazan la salud, el bienestar y la productividad de los animales. Varios informes han dejado patente que las infecciones humanas causadas por patógenos resistentes a los antimicrobianos pueden guardar relación con el uso de estos fármacos y la resistencia a ellos en animales de producción alimentaria, aunque se ignora la amplitud del fenómeno. Dado que el uso de antimicrobianos provoca la aparición de resistencias, su utilización excesiva o incorrecta en el ganado, tan extendida, resulta preocupante. Para seguir de cerca el progreso de las intervenciones destinadas a reducir la resistencia a los antimicrobianos en el sector ganadero es importante disponer de datos robustos sobre la utilización de estos fármacos y las resistencias a ellos. Varios países tienen datos incompletos sobre las ventas o el uso de antibióticos, de tal modo que lo que hoy sabemos sobre el uso de antimicrobianos a escala mundial reposa principalmente en estimaciones obtenidas por modelización. Los datos sobre la prevalencia de resistencias a los antimicrobianos son fragmentarios, especialmente en los países de renta baja o mediana, pero en algunas regiones de renta alta existen datos bastante robustos. Conviene señalar también la existencia de directrices y protocolos de seguimiento que permiten disponer de datos mundialmente armonizados en la materia. Para reducir las resistencias a los antimicrobianos, dos factores clave son la prevención de enfermedades sin recurrir a estos fármacos y el uso racional de los mismos, factores que pasan por lo siguiente: a) servicios veterinarios accesibles y asequibles para los productores; b) venta de antibióticos únicamente con receta; c) los veterinarios no deben percibir ingresos ligados a la venta o prescripción de antibióticos; d) los veterinarios deben contar con sólidos conocimientos de medicina preventiva, lo que incluye cuestiones de buena producción animal, seguridad biológica eficaz y vacunología; y e) tales medidas deben aportar un valor añadido que resulte atractivo para los ganaderos, de forma que estén dispuestos a pagar por ese servicio.

Influenza A Virus in Backyard Pigs and Poultry in Rural Cambodia.

Surveillance of influenza virus in humans and livestock is critical, given the worldwide public health threats and livestock production losses. Livestock farming involving close proximity between humans, pigs and poultry is often practised by smallholders in low-income countries and is considered an important driver of influenza virus evolution. This study determined the prevalence and genetic characteristics of influenza A virus (IAV) in backyard pigs and poultry in Cambodia. A total of 751 animals were tested by matrix gene-based rRT-PCR, and influenza virus was detected in 1.5% of sampled pigs, 1.4% of chickens and 1.0% of ducks, but not in pigeons. Full-length genome sequencing confirmed triple reassortant H3N2 in all IAV-positive pigs and various low pathogenic avian influenza subtypes in poultry. Phylogenetic analysis of the swine influenza viruses revealed that these had haemagglutinin and neuraminidase genes originating from human H3N2 viruses previously isolated in South-East Asia. Phylogenetic analysis also revealed that several of the avian influenza subtypes detected were closely related to internal viral genes from highly pathogenic H5N1 and H9N2 formerly sequenced in the region. High sequence homology was likewise found with influenza A viruses circulating in pigs, poultry and wild birds in China and Vietnam, suggesting transboundary introduction and cocirculation of the various influenza subtypes. In conclusion, highly pathogenic subtypes of influenza virus seem rare in backyard poultry, but virus reassortment, involving potentially zoonotic and pandemic subtypes, appears to occur frequently in smallholder pigs and poultry. Increased targeted surveillance and monitoring of influenza circulation on smallholdings would further improve understanding of the transmission dynamics and evolution of influenza viruses in humans, pigs and poultry in the Mekong subregion and could contribute to limit the influenza burden.

Risk factors associated with Campylobacter detected by PCR in humans and animals in rural Cambodia.

Campylobacter are worldwide-occurring zoonotic bacteria, with the species Campylobacter jejuni and C. coli commonly associated with diarrhoea in children in low-income countries. In this cross-sectional study, the prevalence of C. jejuni and C. coli in human and livestock faecal samples was detected by PCR and zoonotic risk factors associated with human Campylobacter positivity were identified. In total 681 humans and 753 livestock (chickens, ducks, pigs, cattle) from 269 households were sampled. Children aged <16 years were more frequently Campylobacter positive (19%) than adults (8%) and multilevel logistic models revealed that human C. jejuni positivity was associated with the following household practices: home-slaughtering [odds ratio (OR) 2·4, P = 0·01], allowing animals access to sleeping and food preparation areas (OR 2·8, P = 0·02), and eating undercooked meat (OR 6·6, P = 0·05), while frequent consumption of beef was protective (OR 0·9, P = 0·05). Associations were stronger for home-slaughtering (OR 4·9, P = 0·004) with C. jejuni infection in children only. Campylobacter was highly prevalent in pigs (72%) and chickens (56%) and risk factors associated with human Campylobacter positivity were identified throughout the meat production chain. The findings underline the importance of studying source attributions throughout the production chain and the need for upgraded understanding of Campylobacter epidemiology in low-income countries.