Epidemics: What We Need to Know

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 Epidemics: What We Need to Know

“Global health security is only as strong as its weakest link. No-one is safe until everyone is safe”.

WHO,2019.Managing epidemics：Key facts about major deadly diseases Published, World Health Organization Press.

Peter Doherty, 2013. Pandemics: What Everyone Needs to Know, Oxford University Press.

Managing epidemics：Key facts about major deadly diseases Published by the World Health Organization(WHO) in November 2019, which is primarily intended to help the World Health Organization (WHO) country representatives (WRs) to respond effectively and rapidly at the very start of an outbreak. This book consists of three parts: Part One ‘Epidemics of the 21st century’, which provides vital insights on the main features of the 21st century upsurge and the indispensable elements to manage them. Part Two ‘Be in the know. 10 key facts about 15 deadly diseases’ contains key information about 15 diseases (Ebola Virus Disease, Lassa Fever, Crimean-Congo haemorrhagic fever, Yellow Fever, Zika, Chikungunya, Avian and Other Zoonotic Influenza, Seasonal Influenza, Pandemic Influenza, Middle East Respiratory Syndrome, Cholera, Monkeypox, Plague, Leptospirosis and Meningococcal Meningitis). This section provides tips on the interventions required to respond to epidemics of all these diseases. Part Three’Tool boxes’ gives an overview and summarized guidance on some other important topics, including: the role of WHO, the International Coordinating Group, laboratory diagnosis and shipment of infectious diseases substances, and vector control. The manual provides concise and basic up-to-date knowledge with which WRs can advise Ministries of Health in all countries.

In addition, Peter Doherty, an Australian surgeon and Nobel Prize laureate, wrote a book explaining everything you need to know about pandemics, which provide great insights for the managing of the outbreak of the Coronavirus disease 2019.

Epidemics of the 21ST century

The development of new vaccines, antibiotics and other treatments and technologies has heralded a victory over microbes, but they have not disappeared and are even more terrifying.Since 1970, more than 1,500 new pathogens have been discovered, 70 percent of which have been proved to come from animals. Not all have caused public health problems, but many have spread.Indeed, in the first two decades of the 21st century, a number of serious public health events have reminded people around the world of the dangers of infectious diseases, both known and unknown.

Bubonic plague outbreaks have long been considered a thing of the past, but in 2017 a plague outbreak in Madagascar killed 209 people, and nine countries and territories with trade and tourism links to Madagascar went on bubonic plague alert.The lesson was learned: infectious diseases don't disappear over time, and there always seems to be room for new ones.

SARS – Severe acute respiratory syndrome - was unheard of before 2003. But it affected more than 8,000 people, killing about one in ten of them, causing fear and panic across the world, and inflicting enormous economic damage, especially in Asian countries.

In 2009, a novel influenza virus, H1N1, started to spread, creating the first influenza pandemic of the 21st century. But – and this is a reason for cautious hope - it was not as severe as expected thanks to recent preparedness efforts. The importance of these efforts is a core issue in this handbook.

In 2012-2013, a new virus surfaced in the Middle East, causing an epidemic of what became MERS – Middle East respiratory syndrome – that spreads fatally into many countries beyond that region.

The Ebola epidemic in West Africa (Guinea, Liberia, and Sierra Leone) in 2014 was unlike the previous 24 localized outbreaks observed since 1976. Instead of being restricted geographically, this one seriously affected three African countries and spread to six other countries in three continents, and sparked alarm worldwide.

In 2015, the Zika virus, transmitted by the Aedes Aegypti mosquito, triggered a wave of microcephaly in Brazil. This disease causes dreadful damage in the brains of unborn babies. Almost 70 countries, one after another, then experienced their own Zika epidemic. There are probably many more to come, because most of the global intertropical zone has a high density of Aedes Aegypti that transports the disease.

Since the outbreak of a novel coronavirus in Wuhan, China in December 2019, there are over 80,000 confirmed cases in 46 countries.

Source: https://gisanddata.maps.arcgis.com/apps/opsdashboard/index.html#/bda7594740fd40299423467b48e9ecf6

And so a clear pattern continues to take shape. Old diseases – Cholera, Plague, Yellow fever among them – often return, and new ones invariably arrive to join them. About 40 outbreaks of cholera alone are reported to WHO every year.

Challenges and risk factors for 21st century epidemics

The face of epidemics and pandemics has changed in the recent past and continues to do so. Many new factors contribute to an increase in the transmissibility and severity of infectious diseases.

New lifestyles spread diseases further. The epidemics in the 21st century are spreading faster and further than ever..The spread of the disease is exacerbated by more frequent contact between people and between animals and humans.In an era of rapid global change, these factors are almost inevitable.These include the rapid and intensive international and domestic movements of people in the age of globalization, increased transport and international travel, and greater connectivity between major cities as major hubs for air, train, road vehicles, and ships;Unprecedented urbanization and the expansion of urban populations inevitably increase the risk of infectious disease transmission.These risks also occur in densely populated areas around cities, where rural areas overlap with cities and where close and repeated contact between people and livestock, livestock and wildlife increases the likelihood of new outbreaks. And the areas around those cities tend to be poorer, and local residents have less access to health care facilities, as the 2014 ebola outbreak showed. The overcrowded living conditions of millions of refugees affected by war, natural disasters and other factors also increase the risk of infection.The challenges and risk factors of 21st-century pandemics have also undergone potentially dangerous changes in land use, agricultural production and food production (such as markets for live poultry and animals), such as increased contact between humans and wildlife as a result of deforestation.

We have also seen that many traditional containment measures are no longer efficient. They should therefore be re-examined in the light of people’s expectations of more freedom, including freedom of movement. Measures such as quarantine, for example, once regarded as a matter of fact, would be unacceptable to many populations today.The use of antibiotics to treat infections has been a turning point in the 20th century. Antimicrobial resistance is now on a rise. This is a major concern because a resistant infection may kill, can spread to others, and requires finding new ways to treat and limit the spread of the disease.

Epidemics are complex events: complex in their origins, their spread, their effects and their consequences – which can be at one and the same time medical, social, political and economic. The global impact of a single pathogen may vary significantly between settings and there is no one-size-fits-all intervention strategy.

Equity and solidarity issues are often part of the picture: access to medical counter measures remains difficult, especially for low-income countries and countries facing humanitarian emergencies, and this difficulty is worsened when vaccine or treatment production is limited. Market mechanisms do not ensure a fair distribution of resources based on public health demands. Global mechanisms are needed to ensure fair access to life-saving interventions during crises. A number of organizations are dedicated to this goal (among them are CEPI, the Coalition for Epidemic Preparedness Innovations; the International Coordinating Group; GAVI, the Vaccine Alliance; the Pandemic Influenza Preparedness Framework) but more efforts are required.

Epidemics of rumours: a new risk to health. A new word has entered the public health vocabulary: “infodemics”. These can be defined as the rapid spread of information of all kinds, including rumours, gossip and unreliable information. They are spread instantly and internationally through the growing popular use of mobile phones, social media, the internet and other communication technologies. A proliferation of web-based “experts” with diverse and often contradictory views can generate confusion, anxiety and even panic in times of serious infectious outbreaks. False or misleading information is dangerous. It can cause widespread public reluctance to adopt well-founded infection control measures promoted by health authorities – and thus delay essential interventions.

This is why risk communication, a set of sophisticated skills, is increasingly employed by health authorities, agencies, physicians and professional health personnel. It is more important now than ever to learn and apply them. The latest and most accurate information must be conveyed frequently, and uncertainties related to an epidemic must be acknowledged in order to maintain credibility and public trust. Thus, we are recognizing that the complexity of 21st century epidemics and their prevention and control require not just new technologies techniques, but new skills and new attitudes all across the public health community.

Epidemic phases and response interventions

Because new infectious disease threats usually start locally, it is important to understand their dynamics in order to deny them the opportunity to spread further among people and overwhelm health systems. The dynamics of epidemic and pandemic diseases typically occur in four phases, although not all epidemic diseases necessarily go through each phase.The first phase is the introduction or emergence in a community. The second phase is an outbreak with localized transmission, where sporadic infections with the pathogen occur. In the third phase, the outbreak amplifies into an epidemic or pandemic - the pathogen is able to transmit from human to human and causes a sustained outbreak in the community, threatening to spread beyond it. The fourth phase is reduced transmission when human-to-human transmission of the pathogen decreases, owing to acquired population immunity or effective interventions to control the disease. These four phases are illustrated on this page.

The dynamics of epidemics, as described above, define the response and the sequence of interventions that then become necessary. Here, there are five crucial stages. First is the anticipation of new and re-emerging diseases to facilitate faster detection and response; followed by their early detection of emergence in animal and human populations; the third stage is the containment of the disease at the early stages of transmission; followed by the control and mitigation of the epidemic during its amplification; and fifth, the elimination of the risk of outbreak or eradication of the infectious disease. These stages are elaborated in the illustration, and in the section that follows.

Eradication of a disease – much more difficult and rarely achieved - involves the permanent elimination of its incidence worldwide. There is no longer a need for interventions measures. Three criteria need to be met in order to eradicate a disease: there must be an available intervention to interrupt its transmission; there must be available efficient diagnostic tools to detect cases that could lead to transmission; and humans must be the only reservoir.

Four aspects of the response to the outbreak

A comprehensive outbreak response is always complex, comprising many elements that should be harmoniously coordinated. The following response tips are used to organize ideas and to make sure no important point is overlooked. In this handbook, specific tips are listed for each disease which will help keep focus on essential elements of each response. They are organized into four main blocks:

• Coordinating responders (C)

• Health Information (HI)

• Communicating risk (C)

• Health Interventions (HI)

Epidemic control needs to focus on three aspects

A whole-of-society approach is needed to tackle 21st century epidemics so that all the diverse disease drivers are taken into consideration: genetics and biological factors, ecology and the physical environment; human behaviour and demographics; social, political, and economic factors, and so on. Therefore, controlling the epidemic requires a multidisciplinary, multisectoral and multifaceted approach. Moreover, since epidemics are as much a social problem as medical ones, they require solutions that go beyond traditional biomedical approaches. In the epidemic prevention and control work, we should focus on three aspects: first, we should mobilize effective community participation during the epidemic period and mobilize social forces to fight against infectious diseases; Second, Risk communication is one of the key pillars of response to outbreaks. It refers to the real-time exchange of information, advice and opinions between health experts or officials and people who face a threat (hazard) to their survival, health or economic or social well-being. Its ultimate goal is that everyone at risk is able to take informed decisions to mitigate the effects a disease outbreak and take protective and preventive action.Finally, focus on treating patients and protecting the health workforce.

To date, all human pandemics have been caused by pathogens that infect one or other species of warm-blooded vertebrate. Pathogen crossovers from one species to another are inherently random and unpredictable, though some known reservoir populations (like swine in the case of the influenza A viruses) merit close monitoring. The level of risk is increased when rapid forest clearing, odd culinary practices, and adventurous lifestyles bring wildlife species and humans in close contact.

Infectious diseases are no respecters of wealth, power, or personal merit. With a fast spreading respiratory virus, for example, everyone is ultimately in the same boat. As Dr. Tedros Adhanom Ghebreyesus, Director-General of the World Health Organization, says, “Global health security is only as strong as its weakest link. No-one is safe until everyone is safe”.

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