Iranian Journal of Medical Microbiology

.

Coronaviruses are a large family of viruses that contain four known types of alpha, beta, gamma, and delta coronaviruses that exist in animals such as camels, bats, etc. They have the ability to infect humans (1-3). SARS-CoV-1 spread in 2002 in 29 countries caused illness in 8096 cases among whom 774 cases died (4). A few years after the advent of SARS-CoV-1, the MERS-CoV, first appeared in Saudi Arabia in 2012 in a 60-year-old man with severe lung inflammation and spread to 27 countries in the Middle East, North Africa, Europe, Eastern Asia, and the United States. It infected 2519 and killed 866 people (5). Recently, a new type of coronavirus in human that has led to COVID-19 spread first in Wuhan, China, and after a few weeks to various countries all around the world, and it is still distributing. This type of coronavirus along with SARS-CoV-1 and MERS-CoV is a beta type of coronaviruses (6, 7). The researchers initially estimated bats as the host of the virus by sampling seven patients and bats, with 96.2% of the shared genome sequence, moreover, the subsequent research confirmed the pangolin-genome similarity to the SARS-CoV-2 to potentially make this animal as virus host (8, 9).

Expanding COVID-19 in the World
According to the WHO report No.163 on July 1, 2020, COVID-19 has a worldwide population of 10357662, of which 508055 have died. Figure 1 shows the confirmed cases and deaths of COVID-19 in the countries of China, Iran, the Republic of Korea, Italy, Spain, France, the United Kingdom, Germany, the United States of America, and Japan from the date of the first WHO report to July 1, 2020. The first confirmed cases were reported in China in December, Japan on January 15, the Republic of Korea on January 20, Italy on February 5, Iran on February 19, the United States of America on January 23, Spain on February 1, France on January 25, the United Kingdom on February 1, and Germany on January 28 (10). As can be seen on the figure, the highest deaths and confirmed cases were reported in the United States of America. Japan and the Republic of Korea were the first to report COVID-19 in the mid-January; they had the lowest incidence compared to the other countries. The outbreak in China has been stable since late February, and the country has been able to control the disease. The results showed that China, Japan, and Korea have been able to properly identify, diagnose, and treat patients. They have also well implemented community control measures. In fact, this proper performance can be due to the lessons they learned from SARS-CoV-1 and the pandemic flu (11, 12).
 

Figure 1. Total confirmed cases and total deaths of COVID-19 in China, the Republic of Korea, Italy, Iran, Japan, the United States of America, Spain, the United Kingdom, France, and Germany by July 1, 2020. Notes: According to the WHO report No.28, since February 17, 2020, cases with clinical diagnosis have been added along with laboratory tests to provide the reports. (Data source: World Health Organization)

Figure 2 shows the case fatality rate (CFR) curve in different countries from March 9 to July 1, 2020. The CFR globally as of July 1, 2020, was 4.90%. The CFRs in France, Italy, the United Kingdom, Spain, China, Japan, and the United States of America were 18.93%, 14.45%, 13.98%, 11.37%, 5.45%, 5.20%, 4.91%, respectively, which were higher than the global rate while CFRs in Iran, Germany, and the Republic of Korea were 4.75%, 4.61%, and, 2.19%, respectively, which were lower than the global rate. It should be noted that the difference in CFRs between different countries may be affected by testing programs, population age, and underlying diseases (13, 14). Of course, the policy of countries in expressing the statistics, how to perform the control measures, medical facility, people's awareness, and observance of the health principles may have profound effects on the CFRs.
The confirmed cases and deaths of COVID-19 in different regions of the world by July 1, 2020 are shown in Figure 3. The Americas and the African regions have the highest and the lowest confirmed cases and deaths, respectively. The Eastern Mediterranean region has the lowest CFR (2.31%) and the European region has the highest CFR (7.25%) in the world. Region of the Americas accounts for 50.38% of total confirmed cases and 38.94% of total deaths due to COVID-19 as per global statistics (10).
 

Figure 2. CFRs (%) of COVID-19 in France, Italy, the United Kingdom, Spain, Iran, China, the United States of America, the Republic of Korea, Germany, Japan and Globally from March 9 to July 1, 2020. (Data source: World Health Organization).

Figure 3. Total confirmed COVID-19. a) cases and b) deaths per million people by July 1, 2020 (15).
 

Viral diseases have always been a major threat to the world and endangered human health (16). Table 1 shows the statistics on several types of viral diseases: The CFRs were 77.8% for Marburg disease (highest CFR), 41.46% Ebola, 57% Hendra, 9.6% SARS-CoV-1, 0.07% H1N1 Flu, 34.4% MERS-CoV, and 4.90% COVID-19 as of July 1. An important point about the types of viral diseases that the world has gone through or is involved in, is that it can raise the level of readiness of countries and preparation to fight against infectious diseases in the future (17).
 

Table 1. Comparison between different viruses.

Research results on 44627 confirmed cases of COVID-19 in China in different age groups showed that the highest CFR for COVID-19 (14.8%) was over 80 years old (Figure 4). There were also no reports of deaths between the ages of 0 and 9 years. The CFR was 2.8% for males and 1.7% for females. The results showed that in addition to the elderly, those with underlying medical conditions such as hypertension, cancer, cardiovascular disease, diabetes, pulmonary infections, and other chronic diseases are at higher risk of death (22, 23). Also, the CFRs in Italy between the ages of 60-69, 70-79, and 80+ years were reported to be 3.5%, 12.8%, and 20.2%, respectively (13).
 

Prevention and Treatment of the Disease
Experimental results have shown that the virus persists in aerosols for an average of two and a half hours, on surfaces such as plastic and stainless steel for more than three days, on copper for more than four hours, and on cardboard for one day. This causes the virus to spread rapidly and infect more people (35). Among measures to prevent the infection with this new type of coronavirus include: 1) Frequent hand washing with soap and water or alcohol-based solutions especially after contact with contaminated devices, 2) Cover mouth and nose when sneezing and coughing and avoid touching eyes, 3) No contact with animals, 4) Fully cooking of foods, 5) Use of face mask, 6) Keep distance with persons, and 7) Avoid public and overcrowded places. Identifying and isolating patients, and providing inter-individual health education reduces the incidence of the disease (36-38). Due to the rapid spread of the disease in society and its infectious rate, it has created psychological pressure among the general public and patients. The immune system, which plays a key role in counteracting the new coronavirus, would be weakened by the effects of this stress. The stress can reduce natural killer cell activity, lymphocyte proliferation and populations, and antibody production, and reactivates latent viral infections (39, 40). It should be noted that proper management of stress using psychological techniques and nutrition programs can have a significant effect on the fight against COVID-19. Using vitamins A, B, C, D, E, and folic acid, as well as trace elements zinc, selenium, iron, and copper are among the ways to boost the immune system to defense against viral infections (41-43). N-acetylcysteine, as an antioxidant supplement, plays an important role in enhancing immune function in preventing and treating viral infections (44, 45). Medicinal plants are of great importance in the fight against viruses because of their antiviral properties (46). The beneficial effects of using Isatis indigotica (47) and Torreya nucifera (48) against SARS-CoV-1 have been reported before. At present, the treatment and reduction of COVID-19 infection using antiviral drugs such as nucleoside analogues (e.g., Favipiravir, also known as T-705 and ribavirin) and HIV protease inhibitors are currently being studied (49, 50). The beneficial effects of chloroquine and hydroxychloroquine in the treatment of patients have also been reported (51, 52). Recent research has shown that the Angiotensin-converting enzyme 2 (ACE2) receptor inhibition by adding a genetically modified variant of ACE2, called human recombinant soluble ACE2 (hrsACE2) might be used in treating patients with COVID-19 at the early stages of the disease (53). It should be noted that the prescription of these drugs is based on the physician diagnosis and should be used under their medical supervision. One of the factors that can influence the transmission of the virus is the climatic conditions. Research on this subject is being carried out and the current results showed that the effects of high temperature and humidity can reduce the transmission of the coronavirus (54, 55).

The Phases of the Pandemic
Over the past years, zoonotic viral diseases have always been a major threat to human health, and coronaviruses are one of the most important ones (56). COVID-19 is rapidly expanding globally, as announced by the WHO on March 11, 2020, it has become a global pandemic (57). In fact, the announcement of this situation causes countries to enter a new phase of health care to tackle this disease and to raise awareness of the communities and measures needed to rapidly develop vaccine. Programs and resources to cope with COVID-19 expressed by the Centers for Disease Control and Prevention (CDC) and the WHO are similar to those of pandemic influenza. The chains of the global influenza pandemic phases include the research phase (detection of new disease), diagnosis phase (identification of cases worldwide, virus characteristics showing the potential of rapid human-to-human transmission and control measures for the reported cases), initiation phase (worldwide onset of disease wave, the continuous implementation of case-control measures and routine protective measures such as hand washing, enhanced monitoring to detect added cases to determine the time of action and reducing social gatherings), acceleration phase (acceleration of the epidemic wave, the immediate onset of social gatherings reduction measures such as school closures, cancelling social events, self-isolation and quarantine), the deceleration phase (reducing the epidemic wave by reducing the incidence, and planning to suspend or reduce control measures in the community), and the preparation phase (preparations for the next wave of epidemics, infrastructure improvements, protocols for detecting subsequent waves, and evaluation of the response to the first wave) (58-60).

The effects of Coronavirus on the Economy
Infectious diseases have always had a negative impact on the world economy. For example, the estimates showed the impact of SARS-CoV-1 on the gross domestic product (GDP) in Hong Kong, Canada and Singapore at $3.7, $3.2-6.4, and $4.9 billion, respectively (61). Estimates of the influenza epidemic effect in Belgium, France, the Netherlands, and the United Kingdom showed an average drop of 2.5% in their GDP (62). The $2.2 billion GDP loss in Guinea, Liberia, and Sierra Leone in 2015 was due to Ebola (63). COVID-19 is currently expanding globally and is affecting the economies of countries and the factors such as the period of development, infected cases and, CFRs can surely pose a significant threat to the health and economy of the countries (64).

Nanotechnology and Coronaviruses
The importance of nanoscale materials in medical sciences in the diagnosis and treatment has always been of interest to researchers (65). Viruses are one of the types of microbes that are nanometer-sized and their rapid detection can prompt the onset of disease treatment. Therefore, nanoscale materials such as metallic nanoparticles, quantum dots, and carbon nanostructures can play an important role in the timely detection of viruses. Gold and silver nanoparticles have always been of interest to researchers in the field of disease diagnosis and treatment due to their unique optical, physical, and chemical properties (66). Gold nanoparticles were used to detect and diagnosis of patients with SARS-CoV-1 by colorimetric and electrochemical methods in 5 and 120 minutes (67, 68). In the discussion of nanoparticle-based treatments, research work on MERS-CoV suggests that PIH-AuNRs, a gold nanorod complex, can induce disease treatment (69). Nanomedicine research shows the importance and association between nanoparticles and chloroquine for the treatment of COVID-19 (70).

Noun

 

Authors declared no conflict of interests.