Wildlife and Antimicrobial-resistant bacteria in Displaced Areas

Shiori Ikushima, Fukushima Regional Collaborative Center, NIES, Fukushima, Japan

Threat Posed by Antimicrobial-resistant Bacteria (ARB)

Do you know what ARB are?

When we get an infection caused by bacteria, we go to the hospital and get a prescription or anticiotics. However, but if the causative bacteria are drug-resistant, the antimicrobial drugs may no longer work, resulting in a prolonged treatment period, increased financial burden, and death from the infection without cure.

?Antimicrobial resistances are considered a silent pandemic, with an estimated 4.95 million deaths (including associated deaths) worldwide in 2019 due to ARB [1].

?It is also estimated that if no action is taken, the number of deaths caused by ARB will exceed that caused by cancer by 2050 [2].?

Antimicrobial-resistant Bacteria (ARB) in ?Wildlife

Are hospital-based measures alone enough to reduce ARB-related infections??

Zoonoses, which are transmitted between humans and animals (livestock, companion animal, and wildlife), such as covid-19 that recently became a pandemic, are estimated to account for about 60% of all infectious diseases.?

The "One Health" approach, the idea that the health (soundness) of humans, animals and the environment is one, and that all parties involved should work together to solve problems, has been gaining popularity in recent years.?

This concept applies not only to zoonoses, but also to drug resistance, and includes reducing the emergence of ARB in livestock farms and to prevent their release into the environment through wastewater and other means.?

Wildlife is no exception, especially mammals and birds, which have a wide range of behaviors and complex interactions in their ecosystems, have been pointed out as sentinel of contamination in the natural environment and the spread of antibiotic-resistant bacteria in the environment.?

As for wild animals, the prevalance of antibiotic-resistant bacteria differs depending on the habitat.?

Studies conducted outside Japan have shown that wild animals living in close proximity to human communities are more likely to harbor resistance to clinically important antimicrobial agents[3,4].?

Since similar results were obtained in a previous study conducted by the author on deer in Japan [5], we consider the extent of "human activity" to be one key factor in considering the distribution of antimicrobial resistance in wildlife.?

However, it is not known what specific factors promote the possession of ARB in wildlife.

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Is Human Impact Small or large? ?Wildlife in Displaced Areas

There are areas in Fukushima Prefecture that have been uninhabited for 13 years due to the evacuation of residents following nuclear accident at the Fukushima Daiichi Nuclear Power Plant.?

In these areas, wild animals have appeared in urban areas, causing damage such as house invasions. And the Ministry of the Environment has conducted culling to mitigate the damage.?

As mentioned earlier, human activities are considered to have a significant impact on the acquisition of antimicrobial resistance by wild animals.?

With the ongoing depopulation of rural areas in Japan environments such as the Difficult-to-return Zone in Fukushima Prefecture, where people do not live but artifacts are left behind, are likely to increase nationwide in the future.?

However, the modes of acquisition and transmission of antimicrobial resistance in wild animals in such environments is completely unknown.?

In the areas inside the Difficult-to-return Zones, the evacuation order was lifted in November 2023 for the entire ?Specified Reconstruction and Revitalization Base Area, decontamination and infrastructure development, and other community development projects are steadily progressing in anticipation of the ?return of residents and the establishment of new residences.?

Under these circumstances, it is extremely important to ensure public health in the area, and we believe that wildlife surveillance on clinically-relevant ARB (analysis of the temporal and spatial distribution and characteristics of antimicrobial-resistant strains) will help us identify the ARB-related public health concern in these areas and judge the need for mitigating measures of ARB.?

In addition, we would like to collect samples and analyze data on wildlife inhabiting outside the Difficult-to-return Zone to clarify how habitat characteristics and wildlife density affect the acquisition and spread of ARB.

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Risk of Wildlife Carrying ARB

In countries with good sanitary conditions such as Japan, it is not well understood how antimicrobial-resistant bacteria carried by wild animals are transmitted to humans and animals (livestock and companion animal).?

In Japan, human-wildlife conflicts have increased in recent years, with wild animals appearing in urban areas and agricultural lands, and it is believed that a situation has arisen in which transmission between the two is likely to occur.?

On the other hand, even if transmission from wild animals to humans, domestic animals, etc. ?were to occur, the impact of wildlife-derived ARB can be viewed as small in an environment where the original prevalence rate is lower in wildlife than that of human or domestic animals, or wildlife-derived ARB are less virulent than those from human-related environment.?

What is important at this stage is to accumulate knowledge on the factors influence on distribution and pathogenicity of ARB in the environment, including wildlife, the existence of mutual transmission routes with humans and domestic animals, the effects of ARB on wildlife themselves, and the evolution of ARB in wildlife.?

I would like to work hard every day so that this research can be of some help in the reconstruction of Fukushima Prefecture and the establishment of a monitoring system for ARB in wildlife.

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References?????????????????????????? ?????????????????????????????????

1.???????? Antimicrobial Resistance Collaborator (2022) Global burden of bacterial antimicrobial resistance in 2019: a systematic analysis. Lancet 399:629-655.

2.???????? O’Neill J (2016) Tackling drug-resistant infections globally: final report and recommendations. The Review on Antimicrobial Resistance, Government of the United Kingdom, London.

3.???????? Hassell JM (2019) Clinically relevant antimicrobial resistance at the wildlife–livestock–human interface in Nairobi: An epidemiological study. Lancet Planet Health 3:e259–e269.

4.???????? Wyrsch ER (2022) Urban wildlife crisis: Australian silver gull is a bystander host to widespread clinical antibiotic resistance. mSystems 7:00158-22.

5.???????? Ikushima S (2023) Characterization of quinolone-resistant and extended-spectrum β-lactamase-producing Escherichia coli derived from sika deer populations of the Nara Prefecture, Japan. J Vet Med Sci 85:937-941.