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News Article

Study maps antimicrobial resistance in livestock in low- and middle-income countries

Maps summarize current knowledge and provide policymakers a baseline with which to monitor antimicrobial resistance levels in animals and to target interventions across regions

An international team of researchers has shown that antimicrobial-resistant infections are rapidly increasing in animals in low- and middle-income countries (LMICs). The team, led by Thomas Van Boeckel, SNF Assistant Professor of Health Geography and Policy at ETH Zurich, has published a map of antimicrobial resistance (AMR) in the journal Science.

The team of researchers from ETH, Princeton University and Université Libre de Bruxelles, gathered thousands of publications as well as unpublished veterinary reports from around the world. They identified 901 point prevalence surveys reporting AMR rates in animals and food products in LMICs. Their analysis focused on resistance in Escherichia coli, Campylobacter spp., nontyphoidal Salmonella spp., and Staphylococcus aureus.

According to this study, the regions associated with high rates of AMR in animals are northeast China, northeast India, southern Brazil, Iran and Turkey. In these countries, the bacteria listed above are now resistant to a large number of drugs that are used not only in animals but also in human medicine. An important finding of the study is that so far, few resistance hotspots have emerged in Africa with the exception of Nigeria and the surroundings of Johannesburg.

The highest resistance rates were associated with the antimicrobials most frequently used in animals: tetracyclines, sulphonamides, penicillins and quinolones. In certain regions, these compounds have almost completely lost their efficacy to treat infections.

The researchers introduced a new index to track the evolution of resistance to multiple drugs: the proportion of drugs tested in each region with resistance rates higher than 50%. Globally, this index has almost tripled for chicken and pigs over the last 20 years. Currently, one third of drugs fail 50% of the time in chicken and one quarter of drug fail in 50% of the time in pigs.

“This alarming trend shows that the drugs used in animal farming are rapidly losing their efficacy,” Van Boeckel says. This will affect the sustainability of the animal industry and potentially the health of consumers.

It is of particular concern that AMR is rising in developing and emerging countries because this is where meat consumption is growing the fastest, while access to veterinary antimicrobials remains largely unregulated. “Antimicrobial resistance is a global problem. There is little point in making considerable efforts to reduce it on one side of the world if it is increasing dramatically on the other side,” the ETH researcher says.

However, the maps do not cover the entire research area; there are large gaps in particular in South America, which researchers attribute to a lack of publicly available data. “There are hardly any official figures or data from large parts of South America,” says co-author and ETH postdoctoral fellow Joao Pires. He said this surprised him, as much more data is available from some African countries, despite resources for conducting surveys being more limited than in South America.

The team has created an open-access web platform to share their findings and gather additional data on resistance in animals. For example, veterinarians and state-authorities can upload data on resistance in their region to the platform and share it with other people who are interested.

Van Boeckel hopes that scientists from countries with more limited resources for whom publishing cost in academic journal can be a barrier will be able to share their findings and get recognition for their work on the platform. “In this way, we can ensure that the data is not just stuffed away in a drawer” he says, “because there are many relevant findings lying dormant, especially in Africa or India, that would complete the global picture of resistance that we try to draw in this first assessment. The platform could also help donors to identify the regions most affected by resistance in order to be able to finance specific interventions.

Article: Van Boeckel, T. P.; Pires, J.; Silvester, R.; Zhao, C.; Song, J.; Criscuolo, N. G.; Gilbert, M.; Bonhoeffer, S.; Laxminarayan, R. (2019). Global trends in antimicrobial resistance in animals in low- and middle-income countries. Science, vol. 365, issue 6459, eaaw1944, doi: 10.1126/science.aaw1944

Article details

  • Date
  • 01 October 2019
  • Source
  • ETH Zurich
  • Subject(s)
  • Food Animals