Corona virus disease

Saket Mehta

Cse Dept.,Galgotias University,Greater Noida,India

ABSTRACT

The coronavirus disease (COVID-19) has been identified as the cause of an outbreak of
respiratory illness in Wuhan, Hubei Province, China beginning in December 2019. As of 29
March 2020, this epidemic had spread to 199 countries with 707,926 confirmed cases, including
33529 deaths. The World Health Organization has declared it a Public Health Emergency of
International Concern.It is a global pandemic now and send whole world to quarintine.No
vaccines have been found yet.

KEYWORD

Covid-19,coronavirus,globlal pandemic,Wuhan,flu,lockdown,fever,respiratory
problem,epidemic.

INTRODUCTION

Coronaviruses are important human and animal pathogens. At the end of 2019, a novel
coronavirus was identified as the cause of a cluster of pneumonia cases in Wuhan, a city in the
Hubei Province of China. It rapidly spread, resulting in an epidemic throughout China, followed
by an increasing number of cases in other countries throughout the world. In February 2020, the
World Health Organization designated the disease COVID-19, which stands for coronavirus
disease 2019 . The virus that causes COVID-19 is designated severe acute respiratory syndrome
coronavirus 2 (SARS-CoV-2); previously, it was referred to as 2019-nCoV.

ROUTES OF TRANSMISSION

Understanding of the transmission risk is incomplete. Epidemiologic investigation in

Wuhan at the beginning of the outbreak identified an initial association with a seafood market
that sold live animals, where most patients had worked or visited and which was subsequently
closed for disinfection . However, as the outbreak progressed, person-to-person spread became
the main mode of transmission.

COVID-19 is transmitted via droplets and fomites during close unprotected contact between an
infector and infectee . Airborne spread has not been reported for COVID-19and it is not believed
to be a major driver of transmission based on available evidence ;however, it can be envisaged if
certain aerosol-generating procedures are conducted in health care facilities.
In China, human-to-human transmission of the COVID-19 virus is largely occurring in families.
The Joint Mission received detailed information from the investigation of clusters and some
household transmission studies, which are ongoing in a number of Provinces. Among 344clusters
involving 1308cases(out of a total 1836 cases reported) in Guangdong Province and Sichuan
Province, most clusters (78%-85%)have occurred in families .Household transmission studies are
currently underway, but preliminary studies ongoing in Guangdong estimate the secondary attack
rate in households ranges from 3-10%.

Clinical features of Covid-19

The complete clinical manifestation is not clear yet, as the reported symptoms range from
mild to severe, with some cases even resulting in death . The most commonly reported symptoms
are fever, cough, myalgia or fatigue, pneumonia, and complicated dyspnea, whereas less
common reported symptoms include headache, diarrhea, hemoptysis, runny nose, and phlegm-
producing cough . Patients with mild symptoms were reported to recover after 1 week while
severe cases were reported to experience progressive respiratory failure due to alveolar damage
from the virus, which may lead to death . Cases resulting in death were primarily middle-aged
and elderly patients with pre-existing diseases (tumor surgery, cirrhosis, hypertension, coronary
heart disease, diabetes, and Parkinson’s disease) .

In a study describing 138 patients with COVID-19 pneumonia in Wuhan, the most common
clinical features at the onset of illness were [38]:

●Fever in 99 percent

●Fatigue in 70 percent

●Dry cough in 59 percent

●Anorexia in 40 percent

●Myalgias in 35 percent

●Dyspnea in 31 percent

●Sputum production in 27 percent

Other, less common symptoms have included headache, sore throat, and rhinorrhea. In addition
to respiratory symptoms, gastrointestinal symptoms (eg, nausea and diarrhea) have also been
reported; and in some patients, they may be the presenting complaint .

Chest CT in patients with COVID-19 most commonly demonstrates ground-glass opacification

with or without consolidative abnormalities, consistent with viral pneumonia [60,67]. Case series
have suggested that chest CT abnormalities are more likely to be bilateral, have a peripheral
distribution, and involve the lower lobes. Less common findings include pleural thickening,
pleural effusion, and lymphadenopathy.

Virology

Full-genome sequencing and phylogenic analysis indicated that the coronavirus that
causes COVID-19 is a betacoronavirus in the same subgenus as the severe acute respiratory
syndrome (SARS) virus (as well as several bat coronaviruses). The structure of the receptor-
binding gene region is very similar to that of the SARS coronavirus, and the virus has been
shown to use the same receptor, the angiotensin-converting enzyme 2 (ACE2), for cell entry .
The Coronavirus Study Group of the International Committee on Taxonomy of Viruses has
proposed that this virus be designated severe acute respiratory syndrome coronavirus 2 (SARS-
CoV-2).

The Middle East respiratory syndrome (MERS) virus, another betacoronavirus, appears more
distantly related . The closest RNA sequence similarity is to two bat coronaviruses and it appears
likely that bats are the main source; whether COVID-19 virus is transmitted directly from bats or
through some other mechanism ( through an intermediate host) is unknown .

On 30 December2019, three bronchoalveolar lavage samples were collected from a patient with
pneumonia of unknown etiology –a surveillance definition established following the SARS
outbreak of 2002-2003 –in Wuhan Jinyintan Hospital.Real-time PCR(RT-PCR)assayson these
samples were positive for pan-Betacoronavirus.Using Illumina and nanopore
sequencing,thewhole genome sequences of the virus were acquired. Bioinformatic analyses
indicated that the virushad features typical of thecoronavirus family and belonged tothe
Betacoronavirus 2B lineage. Alignment of the full-length genome sequence of the COVID-19
virusand other available genomes of Betacoronavirus showed the closest relationship was with
the bat SARS-like coronavirus strain BatCov RaTG13,identity 96%.Virus isolation was
conducted with various cell lines, such as human airway epithelial cells, Vero E6, and Huh-7.
Cytopathic effects (CPE) were observed 96 hours after inoculation. Typical crown-like particles
were observed under transmission electron microscope (TEM) with negative staining. The
cellular infectivity of the isolated viruses could be completely neutralized by the sera collected
from convalescent patients. Transgenic human ACE2 mice and Rhesus monkey intranasally
challenged by this virus isolate induced multifocal pneumonia with interstitial hyperplasia.The
COVID-19 viruswassubsequently detected and isolated in the lung and intestinaltissues of the
challenged animals.

Distribution of coronavirus in world(as of 31 march)

Where count>1000
Prevention measures

1 For Public

1.1Recognize that COVID-19 is a new and concerning disease ,but that outbreaks can managed
with the right response and that the vast majority of infected people will recover.
1.2 Begin to adopt and rigorously practice the most important preventive measures for COVID-
19 by frequent hand washing and always covering your mouth and nose when sneezing or
coughing.

1.3 Continually update yourself on COVID-19and its signs and symptoms (i.e. fever and dry
cough), because the strategies and response activities will constantly improve as new information
on this disease is accumulating every day.

1.4 Be prepared to actively support a response to COVID-19 in a variety of ways, including the
adoption of more stringent ‘social distancing’ practices and helping the high-risk elderly
population.

2 For countries with imported cases and/or outbreaks of COVID-19

2.1 Immediately activate the highest level of national Response Management protocols to
ensurethe all-of-government and all-of-society approach needed to contain COVID-19 with non-
pharmaceutical public health measures

2.2Prioritize active, exhaustive case finding and immediate testingand isolation, painstaking
contact tracing and rigorous quarantine of close contacts

2.3 Fully educate the general public on the seriousness of COVID-19 and their role in preventing
its spread

2. 4 Immediately expand surveillance to detect COVID-19 transmission chains, by testing all

patients with atypical pneumonias, conducting screening in some patients with upper respiratory
illnesses and/or recent COVID-19 exposure, and adding testing for the COVID-19 virus to
existing surveillance systems (e.g. systems for influenza-like-illness and SARI)

2.5 Conduct multi-sector scenario planning and simulations for the deployment of even more
stringent measures to interrupttransmission chains as needed (e.g. the suspension of large-scale
gatherings and the closure of schools and workplaces).

3 For uninfected countries

3.1 Prepare to immediately activate the highest level of emergency response mechanisms to
trigger the all-of-government and all-of society approach that is essential for early containment
of a COVID-19 outbreak .

3.2 Rapidly test national preparedness plans in light of new knowledge on the effectiveness of
non-pharmaceutical measures against COVID-19; incorporate rapid detection, largescale case
isolation and respiratory support capacities, and rigorous contact tracing and management in
national COVID-19 readiness and response plans and capacities.
3.3 Immediately enhance surveillance for COVID-19 as rapid detection is crucial to containing
spread; consider testing all patients with atypical pneumonia for the COVID-19 virus,and adding
testing for the virus to existing influenza surveillance systems.

3.4 Begin now to enforce rigorous application of infection prevention and control measures in all
healthcare facilities, especially in emergency departments and outpatient clinics, as this is where
COVID-19 will enter the health system.

Conclusion

There has been a rapid surge in research in response to the outbreak of COVID-19.
During this early period, published research primarily explored the epidemiology, causes,
clinical manifestation and diagnosis, as well as prevention and control of the novel coronavirus.
Although these studies are relevant to control the current public emergency, more high-quality
research is needed to provide valid and reliable ways to manage this kind of public health
emergency in both the short- and long-term.

References

1. WMHC. Wuhan Municipal Health and Health Commission’s Briefing on the Current
Pneumonia Epidemic Situation in Our City. 2020.
http://wjw.wuhan.gov.cn/front/web/showDetail/2019123108989. Accessed 1 Feb 2020

2. Li Q, Guan X, Wu P, Wang X, Zhou L, Tong Y, et al. Early transmission dynamics in Wuhan,

China, of novel coronavirus-infected pneumonia. N Engl J Med. 2020.
https://doi.org/10.1056/NEJMoa2001316.

3. WHO. Novel Coronavirus-Japan (ex-China). 2020. https://www.who.int/csr/don/17-january-

2020-novel-coronavirus-japan-ex-china/en/Accessed 1 Feb 2020

4. BBC news. https://www.bbc.com/news/world-51235105

5.World health organization(WHO). https://openwho.org/courses/introduction-to-ncov