Human Ecologyと感染症

抄録

When we apply the perspective of human ecology, in which the human-ecosystem is considered as the interrelationships between human-being and environments mediated by language, social organization and technology, the infectious diseases can be considered as an aspect of the apparent effects on human population by pathogens, as one of the components of biological environments.

The type of infectious diseases is related with the lifestyle and the population size, which have changed with the beginning of settled farming and the establishment of cities.

The applicable technology to infectious diseases includes the vaccination and the treatment with specific drugs, but those are unavailable during the early stage of pandemic. The spread of emerging infectious diseases accelerated by globalization and population ageing have made the current world more vulnerable. Until the successful technology development, the applicable measures are only non-pharmaceutical interventions (NPIs) including lockdown and behavioral changes.

When we look back how the human society tackled COVID-19 pandemic, the early establishment of pathogen identification and confirmatory diagnostic method was the technological advantage compared with previous pandemics. However, the fact that only a part of COVID-19 becomes symptomatic and the high infectiousness during asymptomatic or presymptomatic period made it difficult to prevent the spread over the borders. Since the IHR2005 has to minimize the effect of control measures on global trade and transportation, most developed countries have chosen to keep economic activities including global trade and transportation, which lead to exponential increase of new cases, resulted in overwhelmed health care system with high mortality. Highly effective vaccines have been developed very fast, but combination with NPIs is still necessary for successful suppression.