Of Mice and Schoolchildren: A Conceptual History of Herd Immunity

This article explores a tension at the core of the concept of herd immunity that has been overlooked in public and scientific discussions‒namely: how can immunity, a phenomenon of individual biological defenses, be made relevant to populations? How can collectives be considered “immune”? Over the course of more than a century of use of the term, scientists have developed many different understandings of the concept in response to this inherent tension. Originating among veterinary scientists in the United States in the late 19th century, the concept was adopted by British scientists researching human infectious disease by the early 1920s. It soon became a staple concept for epidemiologists interested in disease ecology, helping to articulate the population dynamics of diseases such as diphtheria and influenza. Finally, though more traditional understandings of the concept remained in scientific use, in the era after World War II, it increasingly came to signal the objective and outcome of mass vaccination. Recognizing the complexity of scientific efforts to resolve the paradox of herd immunity may help us consider the best distribution of immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).(Am J Public Health. Published online ahead of print June 10, 2021: e1–e8. https://doi.org/10.2105/AJPH.2021.306264 )

Understanding how temperature shifts could impact infectious disease

Climate change is expected to have complex effects on infectious diseases, causing some to increase, others to decrease, and many to shift their distributions. There have been several important advances in understanding the role of climate and climate change on wildlife and human infectious disease dynamics over the past several years. This essay examines 3 major areas of advancement, which include improvements to mechanistic disease models, investigations into the importance of climate variability to disease dynamics, and understanding the consequences of thermal mismatches between host and parasites. Applying the new information derived from these advances to climate–disease models and addressing the pressing knowledge gaps that we identify should improve the capacity to predict how climate change will affect disease risk for both wildlife and humans.

The use of Hydroxychloroquine in the Treatment of COVID-19

COVID-19 is a newly emerging human infectious disease of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) origin described as a pandemic by the World Health Organisation (WHO) on March 11, 2020. There is currently no definitive cure for COVID-19; however, among the many treatment strategies, hydroxychloroquine has been suggested as a potential treatment. The purpose of this article was to review the pharmacological properties and mechanism of COVID-19 treatment with hydroxychloroquine and its potential use on the current COVID-19 pandemic.

The accelerated infectious disease risk in the Anthropocene: more outbreaks and wider global spread

The greatly accelerated economic growth during the Anthropocene has resulted in astonishing improvements in many aspects of human well-being, but has also caused the acceleration of risks, such as the interlinked biodiversity and climate crisis. Here, we report on another risk: the accelerated infectious disease risk associated with the number and geographic spread of human infectious disease outbreaks. Using the most complete, reliable, and up-to-date database on human infectious disease outbreaks (GIDEON), we show that the number of disease outbreaks, the number of diseases involved in these outbreaks, and the number of countries affected have increased during the entire Anthropocene. Furthermore, the spatial distribution of these outbreaks is becoming more globalized in the sense that the overall modularity of the disease networks across the globe has decreased, meaning disease outbreaks have become increasingly pandemic in their nature. This decrease in modularity is correlated with the increase in air traffic. We finally show that those countries and regions which are most central within these disease networks tend to be countries with higher GDPs. Therefore, one cost of increased global mobility and greater economic growth is the increased risk of disease outbreaks and their faster and wider spread. We briefly discuss three different scenarios which decision-makers might follow in light of our results.

On the Human Infectious Disease Covid-19 Protective Clothing

The temperature distribution and thickness design of the human infectious disease COVID-19 protective clothing are studied in this paper. Based on the data provided by China mathematical modeling competition in 2018. We establish the temperature distribution model and skin layer heat conduction and burn model. The interface continuous conditional difference method, differential iterative method, least squares method and the chasing method are used to solve the given temperature distribution on the the human infectious disease COVID-19 protective clothing in the environment, and analyze the human infectious disease COVID-19 protective clothing meeting the actual needs.

Complete genome of a Measles virus from Roraima state, Brazil

SUMMARYMeasles is a human infectious disease of global concern caused by the measles virus. In this study, we report the complete genome sequencing of one measles isolate, genotype D8, obtained in Boa Vista city, the capital of the Roraima State, Brazil, directly from the urine sample. Phylogenetics reconstruction grouped the genome described in this study with samples from Australia, Italy, United Kingdom, and the USA. To our knowledge, this is the first complete genome of a wild-type measles virus from Latin America. Therefore, the present data strengthens the current knowledge about the molecular epidemiology of measles worldwide.SponsorshipsCNPq / CAPES / MS-DECIT / Fiocruz

Dogs (Canis familiaris) as Sentinels for Human Infectious Disease and Application to Canadian Populations: A Systematic Review

In a world where climate change, vector expansion, human activity, and pathogen dispersal do not respect boundaries, the human–animal–pathogen interface has become less defined. Consequently, a One Health approach to disease surveillance and control has generated much interest across several disciplines. This systematic review evaluates current global research on the use of domestic dogs as sentinels for human infectious disease, and critically appraises how this may be applied within Canada. Results highlighted a bias in research from high- and middle-income-economy countries, with 35% of the studies describing data from the Latin America/Caribbean region, 25% from North America, and 11% from the European/Central Asia region. Bacteria were the most studied type of infectious agent, followed by protozoa, viruses, helminths, and fungi. Only six out of 142 studies described disease in Canada: four researched a variety of pathogens within Indigenous communities, one researched Borrelia burgdorferi in British Columbia, and one researched arboviruses in Quebec. Results from this review suggest that dogs could provide excellent sentinels for certain infectious-disease pathogens in Canada, yet are currently overlooked. Further research into the use of dog-sentinel surveillance is specifically recommended for California serogroup viruses, Chikungunya virus, West Nile virus, Lyme borreliosis, Rickettsia spp., Ehrlichia spp., and Dirofilaria immitis.