COVID-19 emerged in Wuhan, China in late 2019 and has since spread globally. As of July 2020, there have been over 14.9 million confirmed cases and 610,000 deaths worldwide. While the respiratory system is most commonly affected, SARS-CoV-2 can impact multiple organ systems. Clinical manifestations vary from mild to severe, and complications may include acute respiratory distress syndrome, cardiovascular issues, and neurological effects. Ongoing research is examining vaccine development, treatments, virus pathogenesis, and long-term health impacts.

1. COVID-19
Written and published by
Elaheh Kordzadeh-Kermani
Hossein Khalili
& Iman Karimzadeh
Presented by Saba Idrees
From MS Microbiology.

3. Introduction
• In December 2019, a novel coronavirus (initially
named 2019-nCov) emerged in Wuhan, China, causing
an outbreak of viral pneumonia.
• Later named SARS-CoV-2 due to structural similarities
with SARS-CoV(2003 outbreak).
• Rapid global spread, with significant morbidity and
mortality.
• Presentation aims to review clinical characteristics,
pathogenesis, and ongoing research efforts.

4. Key Facts and Figures
• As of July 22, 2020:
• Over 14.9 million confirmed cases worldwide.
• More than 610,000 deaths attributed to COVID-19.
• Rapid spread across continents, raising global concern.
• Human-to-human transmission via respiratory
droplets, aerosols, direct contact, and possibly fecal-
oral route.

5. Clinical Manifestations and
Complications
• Common symptoms: fever, cough, fatigue, anorexia,
dyspnea, myalgia.
• Atypical presentations: lack of fever, radiological
abnormalities
• Asymptomatic carriers facilitate transmission.
• Complications: respiratory system involvement
(ARDS), cardiovascular impact (hypertension, heart
disease), and more.

6. Pathogenesis and Mechanisms
• ACE 2 receptor: key for viral entry into host cells.
• SARS-CoV-2 binds ACE 2 receptors with higher
affinity than SARS-CoV.
• ACE 2/angiotensin (1–7) axis disturbance linked to
clinical features
• Evidence of ACE 2 expression correlation with
age, sex, and organ involvement.
• Other potential entry routes: CD 147 receptors,
ongoing research.

7. Ongoing Research and
Management Strategies
• Ongoing efforts to develop vaccines: adenovirus-
based, mRNA-based, and ChAdOx1 vaccine trials.
• Therapeutic approaches: initial use of chloroquine,
hydroxychloroquine; remdesivir's controversial
efficacy.
• Clinical manifestations influencing outcomes: age,
comorbidities, immunosuppressive therapies.
• Further research crucial for improved treatment
and prevention strategies.

8. Neurological Involvement
• COVID-19 has shown to have neurological effects,
including anosmia (loss of smell) and ageusia (loss of
taste).
• Some patients experience neurological symptoms like
headaches, dizziness, and confusion.
• Reports of more severe neurological complications
like encephalitis and Guillain-Barré syndrome have
also emerged.

10. Respiratory Implications
• Severe cases of COVID-19 often lead to acute
respiratory distress syndrome (ARDS).
• ARDS results from an excessive immune response
leading to lung inflammation and fluid accumulation.
• Mechanical ventilation is often required to manage
severe respiratory distress.

12. Gastrointestinal Involvement
• Digestive symptoms such as nausea, vomiting, and
diarrhea have been reported.
• ACE 2 receptors in the gastrointestinal tract may
facilitate viral entry and replication.
• Gastrointestinal symptoms can occur before or in the
absence of respiratory symptoms.

13. Ophthalmic Implications
• Conjunctivitis (pink eye) has been observed in
some COVID-19 patients.
• Although ocular transmission is possible,
respiratory droplets remain the primary mode of
infection.
• Proper eye hygiene is advised to reduce potential
transmission through the eyes.

15. Psychological Impact
• COVID-19 has led to increased stress, anxiety, and
depression globally.
• Social isolation, uncertainty, and fear of the virus
contribute to psychological distress.
• Healthcare providers and vulnerable populations are
particularly susceptible to psychological strain.

16. Reproductive System
• Limited evidence on the impact of COVID-19 on the
reproductive system.
• Concerns exist about potential effects on fertility and
pregnancy outcomes.
• Research is ongoing to understand the virus's impact
on reproductive health.

17. Long COVID
• Some individuals experience persistent symptoms long
after recovering from acute COVID-19.
• Symptoms include fatigue, shortness of breath,
cognitive issues, and more.
• Long COVID's exact mechanism and management are
still being studied.

18. Pediatric Implications
• Children usually experience milder symptoms
compared to adults.
• Multisystem Inflammatory Syndrome in Children
(MIS-C) is a rare but severe complication linked to
COVID-19.
• Pediatric patients require careful monitoring and
follow-up to detect any long-term effects.

19. Vaccination and Immunity
• COVID-19 vaccines have been developed to provide
immunity against the virus.
• Vaccination efforts aim to reduce severe cases,
hospitalizations, and deaths.
• Variants of the virus may impact vaccine effectiveness
and require ongoing research.

20. Public Health Measures
• Preventive measures like mask-wearing, hand hygiene,
and social distancing remain crucial.
• Public health campaigns promote vaccination and
adherence to guidelines.
• Global collaboration and research continue to inform
strategies for pandemic control.

21. Reproductive System & COVID-
19
• Limited data on COVID-19's effects on pregnancy.
• Increased risk of miscarriage, preterm delivery, and
growth restriction.
• Observations of preeclampsia-like symptoms.
• ACE 2 receptors in reproductive tissues might
facilitate viral entry.

22. Gastrointestinal Involvement
• 2-10% of COVID-19 patients experience GI
symptoms.
• Diarrhea and vomiting as initial presentations.
• ACE 2 receptors in GI tract epithelial cells.
• Viral invasion and disturbance in RAS system linked
to GI symptoms.

23. Neuromuscular Complications
• Neurological symptoms in 36% of COVID-19
patients.
• CNS symptoms linked to olfactory bulb route.
• Skeletal muscle injury in severe cases.
• Rhabdomyolysis and Guillain-Barre syndrome
reported.

24. Central Nervous System
Impact
• 88% of severe cases display neurologic
manifestations.
• Neuroinvasive potential of SARS-CoV-2.
• CNS entry through systemic circulation or
neuronal pathway.
• COVID-19-associated acute ischemic stroke
reported.

25. Ocular Involvement
• SARS-CoV detected in tear samples.
• Possible conjunctivitis via droplet inoculation.
• Ocular symptoms in 2-32% of cases.
• Conjunctival swabs positive for SARS-CoV-2.

26. Skin Involvement
• Cutaneous changes less common.
• Skin conditions related to protective measures.
• Reports of skin rash with petechiae.
• Erythematous rash, urticaria, and vesicles observed.

27. Multiorgan Failure
• Dysregulated immune response in CRS.
• Multiorgan failure, respiratory, and heart failure.
• Secondary hemophagocytic lymphohistiocytosis
(sHLH).
• Cytokine elevation and cytopenia in PIMS-TS.

29. Kawasaki-like Syndrome
• Kawasaki-like syndrome in pediatric patients.
• Named Pediatric Inflammatory Multisystem Syndrome
Temporally associated with SARS-CoV-2 (PIMS-TS)
and Multisystem Inflammatory Syndrome in children
(MIS-C).
• Hyper inflammatory syndrome with various
symptoms.
• Link to antibody-dependent enhancement and hyper
stimulated cytokine release.

30. Conclusion & Future Perspectives
• Respiratory system most commonly affected.
• Other systems involved with varying severity.
• Electrolyte imbalances and inflammatory markers
predict outcomes.
• ACE 2 receptor role and mutation concerns.
• Immune dysregulation and possible interventions.

31. References
• 1. Zhou P, Yang X-L, Wang X-G et al. A pneumonia outbreak
associated with a new coronavirus of probable bat origin. Nature
579(7798), 270–273 (2020).
• 2. World Health Organization. Coronavirus disease 2019 (COVID-19)
situation report. (2020).
http://www.who.int/Docs/DefaultSource/Coronaviruse/Situation-
Reports/20200402-Sitrep-73-Covid-19.Pdf?Sfvrsn=5ae25bc7
4%20CDC-SRaF
• 3. Xiao F, Tang M, Zheng X, Liu Y, Li X, Shan H. Evidence for
gastrointestinal infection of SARS-CoV-2. Gastroenterology 158(6),
1831–1833. e1833 (2020).
• 4. Centers for disease control and prevention. Symptoms of
coronavirus. (2020). http://www.cdc.gov/coronavirus/2019-
ncov/symptoms-testing/symptoms.html
• 5. Guan W-J, Ni Z-Y, Hu Y et al. Clinical characteristics of coronavirus
disease 2019 in China. N. Engl. J. Med. 382(18), 1708–1720 (2020).