Covid-19 means of transmission
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the Pathophysiology of COVID-19 infection, it's main ways of transmission, Viral loading and shedding, symptoms in addition to it's occupational hazards and it's precautions.
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Covid-19 means of transmission
- 1. pediatric dentistry dep. ACU COVID-19 means of Transmission
- 2. AT THE END OF THIS LECTURE YOU WILL BE AWARE OF : 1. Pathophysiology of COVID-19 infection . 2. COVID-19 infection sources . 3. Modes of transmission Of the virus and differentiate between each mode. 4. Acknowledge if COVID-19an airborne transmitted disease or not. 5. COVID-19 Viral loading and shedding 6. Pre-symptomatic transmission of COVID-19. 7. Saliva and salivary glands role in COVID-19 spread. 8. COVID-19 occupational dental hazards. . ILOS
- 3. “Timely, evidence-based information is the best vaccine against rumors and misinformation” —DR.JARBAS BARBOSA,PAHO’sASSISTANT DIRECTOR ”
- 4. pathophysiology 01. How dangerous do you think this virus is?
- 5. Nasal and bronchial and pneumocytes are mostly the target cells. ACE2 AND TMPRSS2 are the responsible receptors for COVID-19 BINDING It’s usually resembling a common cold pathophysiology 01.Asymptomaticstate 01 02 03
- 6. - Day 3- 10. - Active replication of the virus in this phase is present. - The patients usually shows signs and symptoms of fatigue. - pathophysiology 02.UPPER AIRWAYRESONCE 01 02 03
- 7. - >Day 10. the patient usually shows lung injury. - Viral necrosis pathophysiology 03. Inflammatory state 01 02 03
- 9. COVID-19 sources 02. How did coronavirus start and where did it come from?
- 10. corona virussources the whole genome level, the human nCoV-2019 is 96% identical to a bat coronavirus. they provided a partial spike gene to COVID-19 and it was also suggested that the pangolins are a natural reservoir of the COVID-19 virus The resampling similarity codon usage bias of COVID- 19 is similar to that of Bungarus multicinctus snake Bats pangolin Snakes mink - It’s documented that mink shows COVID-19 transmission to human - It also responsible for the so called FVI-spike mutation in one strand of the virus
- 11. Modesof INFECTION How do you think corona virus can be transmitted? 03.
- 12. 01 02 Modes ofINFECTION Bats Animaltohuman humantohuman 2A. Horizontal transmission 1- Direct transmission 2- Droplet transmission 3- Aerosol transmission 4- Fecal-oral transmission 2B. Vertical transmission Snakes pangolin
- 13. Modes ofINFECTION 02 humantohuman 2A. Horizontal transmission Direct contact transmission; - This occur virus transmitted through contaminated objects or surfaces and infecting people through the mouth, nose, or eyes. - Healthcare providers attending with COVID-19 patients are especially at risk of being infected via this mode of disease transmission.
- 14. THEVIRUSAND SURFACES Find out how long the virus stays on different surfaces!
- 15. SURFACE TIME Sprayers 3 hours Copper 4 hours Plastic 2-3 days SURFACE TIME Cardboard 24 hours Steel 2-3 days Wood 4 days COVID-19INDIFFERENT SURFACES
- 16. Modes ofINFECTION 02 humantohuman 2A. Horizontal transmission Droplet transmission; - droplets that contain the virus from reflective coughing or sneezing can transmit the disease. - it’s the most dangerous form of COVID-19 spread among healthcare providers.
- 17. Modes ofINFECTION 02 humantohuman 2A. Horizontal transmission Aerosol transmission; - Aerosol to mean the small respirable particles <5–10 μm that can remain airborne and are capable of short and long range transport. - The virus remains viable for at least 3 h in aerosols and 48 -72 h on stainless steel and plastic surfaces.
- 18. Airborneornot?
- 19. - To date the 1ry concern is near field transmission. - it’snot! less than 1m - According to current evidence Among 75,465 COVID-19 cases in china, airborne transmission was not reported.
- 20. A although the corona virus is not principally an airborne virus, but; ● Normal breathing, talking droplets are within <1 μm . ● Other environmental factors aren’t considered. Eg; humidity and temperature ● Limited empirical data on aerosolized COVID-19. It’snot but…
- 21. Modes ofINFECTION 02 humantohuman 2A. Horizontal transmission Fecal-oral transmission; -gastric glandular, colon, ileum absorptive enterocytes, duodenal and rectal cells shares ACE2. - Clearance of the COVID-19 virus in the respiratory tract occur within two weeks, whereas the feces can remain positive for viral RNA for longer than 4 weeks.
- 23. Modes ofINFECTION 02 humantohuman 2B. Vertical transmission - there’s high expression of ACE2 receptors in the human maternal-fetal inter- phase. - There is low risk for vertical transmission from Maternal COVID-19. - breastfeeding is safe for the newborn.
- 24. viralloadingandshedding - COVID-19 has a median incubation period of 3 days - The median period of viral release from the time patients nasopharyngeal swab tested positive, is 12 days.
- 25. Pre-symptomatic transmission - COVID-19 infection occurred on average 1.99 and 3.68 days before symptom onset of the infector. - There’s at least 65% of transmission occurring before symptom onset. (Tindale et al., 2020) Pre-symptomatic infection as estimated by samples of (serial interval - incubation period), accounting for covariation. Top: Singapore. Bottom: Tianjin. Left: without intermediates. Right: accounting for intermediates. Grey vertical line: 0. Samples below zero indicate pre-symptomatic transmission. In all cases there is substantial pre-symptomatic transmission.
- 26. ● In majority of cases corona virus genome has been detected in the saliva. ● The highest viral load in COVID-19 patients are in the saliva and the sputum. ● The saliva is a convenient noninvasive sample for the diagnosis of COVID-19. Doessalivaplayarole inCOVID-19 SPREAD?
- 27. ● There’s high expression of the ACE2 receptor was found in minor salivary glands. ● the source of virus in saliva has not been fully investigated in most studies. ● the salivary glands can be infected but it’s hard to insure that they act as a reservoir for COVID-19. Arethesalivaryglandsthekey playersinCOVID-19spread?
- 29. 04 05 06 01 02 03 - Aerosols which carry COVID-19 for over 3 hours. - Infection through eyes from splashes and aerosols Subclinical patients can spread COVID-19. - Possibility of COVID-19 inhalation from various dental procedures. - Contaminated environment. Direct contact transmission ; through oral mucosa or contaminated hand and possibility of gloves puncture. Indeed dentalprofessionals athighriskofcontagiondueto;
- 33. 1. Anderson, E. L., Turnham, P., Griffin, J. R., & Clarke, C. C. (2020). Consideration of the Aerosol Transmission for COVID-19 and Public Health. Risk Analysis, 40(5), 902–907. https://doi.org/10.1111/risa.13500 2. da Silva Pedrosa, M., Sipert, C. R., & Nogueira, F. N. (2020). Are the salivary glands the key players in spreading COVID-19 asymptomatic infection in dental practice? Journal of Medical Virology, 1–2. https://doi.org/10.1002/jmv.26316 3. Izzetti, R., Nisi, M., Gabriele, M., & Graziani, F. (2020). COVID-19 Transmission in Dental Practice: Brief Review of Preventive Measures in Italy. Journal of Dental Research, 99(9), 1030–1038. https://doi.org/10.1177/0022034520920580 4. Mason, R. J. (2020). Pathogenesis of COVID-19 from a cell biology perspective. European Respiratory Journal, 55(4), 9–11. https://doi.org/10.1183/13993003.00607-2020 5. Odeh, N. D., Babkair, H., Abu-Hammad, S., Borzangy, S., Abu-Hammad, A., & Abu-Hammad, O. (2020). COVID-19: Present and future challenges for dental practice. International Journal of Environmental Research and Public Health, 17(9). https://doi.org/10.3390/ijerph17093151 6. Passarelli, P. C., Rella, E., Manicone, P. F., Garcia-Godoy, F., & D’Addona, A. (2020). The impact of the COVID-19 infection in dentistry. Experimental Biology and Medicine, 245(11), 940–944. https://doi.org/10.1177/1535370220928905 7. Rahman, H. S., Aziz, M. S., Hussein, R. H., Othman, H. H., Salih Omer, S. H., Khalid, E. S., Abdulrahman, N. A., Amin, K., & Abdullah, R. (2020). The transmission modes and sources of COVID-19: A systematic review. International Journal of Surgery Open, 26(September), 125–136. https://doi.org/10.1016/j.ijso.2020.08.017 8. Safety, F., & Businesses, F. (2020). COVID-19 and Food Safety: Guidance for food businesses: Interim guidance. COVID-19 and Food Safety: Guidance for Food Businesses: Interim Guidance, April, 1–6. https://doi.org/10.4060/ca8660en 9. Tindale, L. C., Stockdale, J. E., Coombe, M., Garlock, E. S., Lau, W. Y. V., Saraswat, M., Zhang, L., Chen, D., Wallinga, J., & Colijn, C. (2020). Evidence for transmission of covid-19 prior to symptom onset. ELife, 9, 1–34. https://doi.org/10.7554/eLife.57149 10. Wiersinga, W. J., Rhodes, A., Cheng, A. C., Peacock, S. J., & Prescott, H. C. (2020). Pathophysiology, Transmission, Diagnosis, and Treatment of Coronavirus Disease 2019 (COVID-19): A Review. JAMA - Journal of the American Medical Association, 324(8), 782–793. https://doi.org/10.1001/jama.2020.12839 References;
Editor's Notes
- PAHO’S ; PAN AMERICAN HEALTH ORGANIZATION
- SARS-CoV-2 targets cells, such as nasal and bronchial epithelial cells and pneumocytes, through the viral structural spike (S) protein that binds to the angiotensin-converting enzyme 2 (ACE2) receptor. The type 2 transmembrane serine protease (TMPRSS2), present in the host cell, promotes viral uptake by cleaving ACE2 and activating the SARS-CoV-2 S protein, which mediates coronavirus entry into host cells
- called the DFVI-spike mutant, has four mu- tations in the gene coding for the spike pro- tein, which helps the virus enter host cells. Experiments with the DFVI strain showed plasma from recovered COVID-19 patients or rabbits immunized with the vi- rus did not neutralize it as efficiently as the unmutated virus. iologist David Kennedy of Pennsylvania State University, University Park, agrees mutations in the spike protein “could completely undermine” vaccine efficacy, especially if they occur in the part of the protein that binds to the human receptor, as one of the four mutations in DFVI does.
- Respiratory air normally contains an abundance of droplets of sizes less than 5 mm in diameter. dan expulsion of droplets from the oral cavity and respiratory tract. In COVID-19 patients these droplets contain a virus that if inhaled or ingested or landing on the mucous membranes will cause disease in people . This mode transmission is the most dangerous form of COVID-19 spread among healthcare providers. The use of PPE with efficient barriers to the droplets and maintenance of personal and environmental hygiene will limit the rate of infections.
- To date, primary concern has focused on near- field transmission, particularly protective of coughing and sneezing from infected individuals, and hand-to- face transport from surfaces. According to current evidence, COVID-19 virus is primarily transmitted between people through respiratory droplets and contact routes. In an analysis of 75,465 COVID-19 cases in China, airborne transmission was not reported Among 75,465 COVID-19 cases in. china, airborne transmission was not reported.
- Incidentally, it was shown that there are high expressions of ACE2 in gastric glandular, colon and ileum absorptive enterocytes, duodenal and rectal cells suggesting the virus spread via the fecal-oral route.
- Not all neonates of COVID-19-positive mothers acquired the disease because one study showed that none of the neonates born of 31 mothers infected with COVID-19 had the disease Since the breast milk of COVID-19-mothers is virus-free, breastfeeding is safe for the newborn. However, mothers should be wearing masks during breastfeeding to minimize the risk of transmitting the infection to the newborns through droplets and aerosols. (Rahman et al., 2020)
- - The most critical characteristics of a COVID-19 virus are their high capacity for shedding, transmission, and spread.
- * Most COVID-19 patients show a high prevalence of the virus in saliva. However, saliva viral load decreases with time. Thus, the saliva is a convenient noninvasive sample for the diagnosis of COVID-19, especially, at the stages of the disease
- IT’S suggested SARS‐CoV‐2 coming directly from the salivary gland might be due to high viral loads at the late stage of the disease and not from individuals with mild, limited, or lack of symptoms. even though the current literature shows that salivary glands can be infected, we cannot affirm that they act as reservoirs for COVID‐19 asymptomatic infections.
- Biologic risk of COVID-19 inhalation transmission is extremely high when performing dental procedures due to the use of handpieces under irrigation, which favors the diffusion of aerosol particles of saliva, blood, and secretions. this production of aerosol facilitates the contamination of the environment and instruments, dental apparatuses, and surfaces. possibility of gloves puncture but it’s not certain possible to get infected via a glove puncture, but this eventual risk can be notably reduced following the same practices that have been followed by the dental community for the protection from several blood-borne pathogens.