All the secrets revealed about the Covid-19 pandemic.
A complete rational guide of its Evolution, Expansion,
Symptoms and First Defense.
Written by Sidney Osler
CHAPTER 1: HUMAN CORONA VIRUS OUTBREAK 2020
As 2019 drew to a close, reports emerged from an outbreak of unexplained aetiology pneumonia, with cases clustered around Wuhan’s Huanan Seafood Wholesale Market, China that sold live fish, poultry, and birds. The cases were observed as of December 8th and the cluster was first identified on December 31st. The market was being shut down on 1 January 2020 and on 7 January a new type of corona virus was officially detected by the Chinese authorities. All suspect cases found were checked by active case finding and retrospective examination. Around 300 cases in Wuhan were believed to have been infected with this new virus, and four died.
It is also suspected that previous outbreaks of similar diseases, including SARS, have arisen from live animal markets. Camels transmit the corona virus which causes MERS to humans. The animal that was the source of the latest corona virus is still unknown, and the collapse of the meat market in Wuhan has made the matter almost impossible to investigate. Bats are considered a possible source, because many viruses, including corona viruses, have adapted to coexist. Nevertheless, it is very likely that the virus was transmitted to an intermediate species from the bats, and then to humans.
Wuhan, a strong virology centre in China, was well placed to diagnose and tackle the outbreak. It has however brought China’s disease preparedness to the test in a part of the world that still regularly remembers the 2003 extreme corona virus outbreak of acute respiratory syndrome (SARS). The virus then spread from China to 25 other nations, infecting over 8,000 people and killing about 800 people before it was contained. In the present case, the pace at which the Chinese authorities announced the outbreak to the international community was commendable and shows that lessons from previous outbreaks have been learned.
As the international community reacts to an outbreak of corona virus induced pneumonia in Wuhan, China, early and transparent data sharing–essential to its protection–is dependent on the trust that the data will not be used without proper attribution to those who created it.
What is the Human Corona virus, and How Dangerous Is It?
Corona viruses are a large virus family usually targeting the respiratory organ. The name is being derived from the Latin word corona, meaning crown, due to the spiky fringe which surrounds these viruses. Many species, such as bats, cats and birds, get sick. Just seven are known to infect humans like Covid-19, SARS, and MERS.
SARS is believed to have developed in China from bats to civet cats to humans; MERS has spread from bats to camels into Middle East humans. No one knows where the Covid-19 came from. For now, livestock in Wuhan, China, a town of 11 million, are thought to have taken the jump late last year. But scholars still seek to understand their exact roots.
As for the signs, in 10 and more than 30 percent of cases, two of the seven corona viruses that infect humans, SARS and MERS, can cause severe pneumonia, and even death. The others, though, show milder effects, like a common cold. Apparently, it’s evident that Covid-19 will kill — but it’s not clear how often or how it relates the fatality rate to SARS and MERS.
Most patients now start with fever, cough, and shortness of breath, according to the Centers for Disease Control and Prevention. An early analysis, published in The Lancet, offered even greater detail. It has looked at a subset of the first 41 patients in Wuhan with confirmed Covid-19. Fever, cough, muscle pain, and exhaustion were the most common symptoms; vomiting, nausea, and coughing up mucus, or blood, were less common. They all had CT scans of pneumonia and lung abnormalities. As for the severity of the disease: 13 people were taken to an ICU, where six died. By January 22, most patients had been discharged from the hospital (68 per cent).
More recently, records have also been made of people with very mild symptoms, such as the cases in southern Germany. There is even evidence that events are asymptomatic. It’s likely that Covid-19 can look more like flu than it does like SARS. That’s because when they are first detected, infectious diseases usually seem more serious, because people appearing in hospitals tend to be the sickest. However, the new virus seems less dangerous than both SARS and MERS.
How Bad Could The Outbreak Be?
The novel corona virus, similar to SARS, seems highly contagious. The size of an epidemic depends on how quickly and easily a virus is transmitted from one person to another. Although work has just started, scientists have estimated that without successful containment measures, every person with the new corona virus could infect between 1.5 and 3.5 people elsewhere. This would make the virus nearly as infectious as SARS, another corona virus that spread in China in 2003 and was contained after 8,098 people were sickened and 774 killed. Those respiratory viruses may move through the air, wrapped in tiny droplets formed when a sick person breathes, speaks, coughs, or sneezes. Some droplets fall within a few feet to the ground. This makes it harder for the virus to get unlike viruses like measles, chickenpox and tuberculosis, which can fly through the air for a hundred miles. Nevertheless, detecting is better than H.I.V. or hepatitis which only spreads by direct contact with an infected person’s body fluids.
If each individual infected with the new corona virus contaminates two to three other people, this may be sufficient to sustain and intensify an epidemic if nothing is done to reduce it.
Contrast that to a virus less infectious, like seasonal flu. Those with the flu appear, on average, to infect 1.3 other people. The difference may seem slight, but the result is a striking contrast: In the same situation, only about 45 people could be infected.
The number of cases outside of China has so far been limited. Yet reports have occurred in several countries in recent days, including the United States, of citizens who have not visited China. In addition, in 2003, the number of cases within China far exceeded the rate of SARS cases. The actual number of cases is almost definitely much greater than the number officially confirmed by laboratory tests.
Thousands of people are suspected of having been infected in Hubei province, where the epidemic started, but have not been officially diagnosed. Doctors say there’s a shortage of test kits and other medical supplies, and residents say it’s almost difficult to get the health care they need to treat the corona virus — or even diagnose it—. Various epidemiological models predict the total number of cases to be 100,000, or more. Experts have urged caution when calculating these figures.
How Deadly Is The Virus?
It is still hard to know. Perhaps the fatality rate is less than 3 per cent, however, much fewer than SARS. This is one of the utmost significant factors, and one of the least known, in how destructive the outbreak will be. Assessing the lethality of a new virus is challenging. The worst cases are usually first identified which may distort our perception of how patients are likely to die. Around one third of Wuhan’s first 41 patients had to be treated in an ICU, many with fever symptoms, serious cough, shortness of breath and pneumonia. But people with mild cases are never allowed to visit a doctor. There may be more deaths than we know therefore, and the death rate may be smaller than we initially thought.
At the same time there may be underreported deaths from the virus. The Chinese cities at the heart of the outbreak are facing a shortage of test kits and hospital beds, and many sick people could not see a doctor. There is still a lot of uncertainty about the existence of this virus and what it is doing. Early indications show that the fatality rate for this virus is significantly lower than that of another corona virus, MERS, which kills about 35 per cent of infected people, and SARS, which kills about 10 per cent. All the diseases tend to bind on proteins on the lung cell surface, but MERS and SARS seem to be more harmful to lung tissue.
Of China’s 17,000 people infected, 82% had moderate infections, 15% had severe symptoms, and 3% were listed as critical. Lower than 2 percent had died from confirmed infections. Many of those that died were elderly men with underlying health issues. The virus causes serious respiratory disease (i.e., pneumonia) and death from mild symptoms. Many deaths occurred in people over the age of 65 and who were also suffering from another chronic condition or illness. Data suggest a case-fatality rate of about 2 percent (meaning 2 deaths out of every 100 confirmed cases), even though it is still too early to give a reliable cipher. If the number of undiagnosed asymptomatic cases or cases with very mild symptoms turns out to be high it could be lower. If the virus mutates, it could intensify. In any case, the fatality rate tends to be smaller than that of SARS (10%), and higher than that of seasonal flu (less than 0.01%).
Where Has the Virus Spread?
We still don’t know how exactly Covid-19 spreads, but we do have a lot of data on how MERS, SARS, and other respiratory viruses travel from person to individual. In fact, this is primarily by exposure to droplets caused by sneezing or coughing. So when a sick individual coughs or sneezes, they let out a mist, and when those droplets touch another person’s nose, eyes, or mouth, they will pass on the virus. In rare cases, a person can indirectly catch a respiratory illness, “by touching droplets on surfaces— and then touching mucosal membranes” in the mouth, eyes, and nose. This is why hand-washing is an important measure of public health and particularly in an outbreak.
The virus spread rapidly because it began in a transport hub. Wuhan is a hard place to get an outbreak in. It has 11 million people, more than the City of New York. On a typical day, 3,500 passengers take direct flights to towns in other countries from Wuhan. Those cities were among the first outside of China to record virus cases. Wuhan is also a major transportation center within China, linked by high-speed trains and domestic airlines to Beijing, Shanghai and other major cities. Up to two million people flew from Wuhan to other places inside China in October and November last year.
During the SARS outbreak in 2003, China had not been nearly as well associated. Large numbers of migrant workers are now moving domestically and internationally— to Africa, other parts of Asia and Latin America, where China’s Belt and Road Initiative is making a huge infrastructure drive. This travel poses a high risk of outbreaks in countries with health-care systems not equipped to handle them, such as Zimbabwe, which is facing a growing hunger and economic crisis.
Furthermore, China has about four times as many passengers on the train and air as it did during the SARS outbreak. China took the unprecedented step of enforcing travel restrictions on tens of millions of people living in Wuhan and surrounding towns. Experts, however, cautioned that the lockout might have come too late, with restricted access to food and medication. Wuhan’s mayor confirmed that five million people had left the city in the run-up to the Lunar New Year, before the restrictions began.
The Mode of Transmission
The Transmission Mode Much of how Covid-19, a new corona virus, spreads is unclear
The Transmission Mode Much of how Covid-19, a new corona virus, spreads is unclear. Current awareness is based in large part on what is learned of related corona viruses. Corona viruses are a large family of viruses commonly found in many different animal species, including camels, goats, cats, and bats. Rarely can animal corona viruses infect people, and then spread among people including MERS, SARS, and now with Covid-19. Most respiratory viruses are spread by sneezing and coughing. Although the Chinese authorities initially played down the possibility of human-to-human transmission, substantial and sustained transmission among people has now become apparent. Chinese scientists have cautioned that some infected people may transmit the virus to others even before they develop illness or experience any symptoms, though a published study documenting asymptomatic transmission in Germany has been criticized as inaccurate.
If the virus can be spread by individuals with no symptoms at all or mild symptoms due to respiratory disease— including headache or back ache— that is terrible. They’re up and about, going to work or the gym or religious services, and breathing on or touching other people when people don’t know they’re sick. Most often, the spreading from person to person happens within close contacts (about 6 feet). It is thought that spreading from person to person occurs primarily through respiratory droplets created when an infected person coughs or sneezes, similar to how influenza and other respiratory pathogens spread. Such droplets may land in nearby people’s mouths or noses, or probably be inhaled into the lungs. Whether a person can get Covid-19 by touching a surface or object with the virus on it, and then touching their own mouth, nose, or probably eyes, is currently unclear. Usually, people are thought to be most infected with most respiratory viruses when they’re most symptomatic (the sickest).
It is important to note that the ease with which a virus spreads will vary from person to person. Many viruses (such as measles) are highly contagious, while other viruses are less so. There’s much more to learn about the transmissibility, frequency, and other characteristics associated with Covid-19 and ongoing investigations. This information will help the risk assessment further.
What Symptoms Should I Look Out For?
Symptoms of this infection include fever, heavy cough and breathing difficulties or shortness of breath. The disease triggers pneumonia and lung lesions. Mild cases may mimic flu or a bad cold, making it difficult to identify. Patients might be familiar with other symptoms, such as gastrointestinal issues or diarrhea. It is known that the incubation period— the duration from exposure to the onset of symptoms — is anywhere from 10 days to two weeks.
See your health care provider if you have a fever or cough and have recently visited China, or spent time with someone who did. Call first, so they can plan for your visit and take steps to prevent potential exposure to other patients and staff.
How Time-consuming Does It Take To Reveal Symptoms?
The new corona virus novel shows symptoms ranging from 2 to 14 days, enabling the disease to go undetected. Reported diseases have ranged from people with little to no symptoms to people who are severely sick and dying with reported Covid-19 infections. Symptoms may include:
• Shortness of breath
This is dependent on what was historically known as MERS virus incubation period. The amount of time it takes for signs to occur after an infected person can be critical for prevention and control. Identified as the duration of incubation, this time helps health officials to isolate or track individuals who may have been exposed to the virus. Nevertheless, if the incubation period is too long or too short, then it may be difficult to implement such steps.
Many diseases, such as influenza, have a brief two to three-day incubation period. Until they show flu symptoms, people can shed infectious virus particles, making it almost impossible to recognize and isolate people who have the virus. Nevertheless, SARS had an incubation period of about five days. It also took four to five days after symptoms started before the virus could be spread to sick people, which gave officials time to stop the infection, and contain the outbreak effectively.
Executives at the Centers for Disease Regulator and Prevention say the incubation period for the current corona virus is 2-14 days. But whether a person can spread the virus before symptoms occur is still not clear, or whether the nature of the disease influences how quickly a patient can spread the virus. This is troubling because it may mean the identification of the infection will elude.