Lessons Learn from SARS The Etiology ,Pathology and Clinical Features of SARS

1. Lessons Learn from SARSThe Etiology ,Pathology and Clinical Features of SARS Nantong Medical College The Department of Pathology Chen Li

2. Introduction SARS is a condition of unknown cause that has recently been recognized in patients in Asia , North America , and Europe . This report summarizes the initial epidemiologic findings , pathologic description , clinical and diagnostic findings.

3. An outbreak of atypical pneumonia, referred to as severe acute respiratory syndrome (SARS) and first identified in Guangdong Province, China, has spread to several cities and countries. The severity of this disease is such that the mortality rate appear to be 3 to 6%. A number of laboratories worldwide have undertaken the identification of the causative agent.

4. Medical personnel , physicians ,nurses and hospital workers are among those commonly infected . Sadly,Dr. Carlo Urbani,the 46-year-old WHO physician and infectious disease specialist whose work defined SARS(Ferbruany 28),and died on March 29 of SARS .

5. The WHO issued a global alert SARS • The first time on march 12 • The second time on march 15 • The third time on march 27 • The international society are taking actions to SARS. The virus has been identified to be coronavirus by the cooperation of laboratories all over the world. The target has been aimed, and the actions are undertaken. This is a battle without fire.

6. 1. Etiology On march 24 ,scientists at the CDC in USA and in Hong Kong announced that a new coronavirus had been isolated from patients with SARS. This coronavirus(COV) has been named publicly by the WHO and member laboratories as “SARS virus”. This is a novel virus that is not closelt related to any of the known clusters of coronaviruses.

7. SARS virus completely newcoronavirus

8. The National Microbiology Laboratory in Canada obtained the Tor2 isolated from a patient in Toronto, and succeeded in growing a coronavirus-like agent in African Green Monkey Kidney (Vero E6) cells. • This virus was purified and its RNA genome extracted and sent to the British Columbia Centre for Disease Control in Vancouver for genome sequencing by the Genome Sciences Centre at the BC Cancer Agency.

9. The coronaviruses are members of a family of enveloped viruses that replicated in the cytoplasm of animal host cells. They are distinguished by the presence of a single-stranded plus sense RNA genome approximately 30 kb in length that has a 5’ cap structure and 3’ polyA tract. Upon infection of a host cell, the 5’ most open reading frame (ORF) of the viral genome is translated into a large polyprotein that is cleaved by viral-encoded proteases to release several nonstructural proteins including an RNA-dependent RNA polymerase (Rep) and ATPase helicase (Hel). These proteins in turn are responsible for replicating the viral genome as well as generating nested transcripts that are used in the synthesis of the viral proteins. The mechanism by which these subgenomic mRNAs are made is not fully understood.

10. SARS virus completely newcoronavirus

11. SARS virus structure S(spite protein) M(membrane protein) E(small membrane protein) HE(hemagglutinin eaterase) N(nucleocapsid protein) RNA genome Some small nonstructure ORFs

12. SARS virus in EM 60-220nm

13. The SARS genomic sequence has been deposited into Genbank (Accession AY274119.3 , Apr. 18 03, Canada)

14. The nucleotide position ,associated ORF and putative transcription regulatory sequences(TRSs).

15. The feature of the Tor2 genome sequence (Canada)

16. The SARS genomic sequence has been deposited into Genbank (Accession AY278554, Apr.18 03, USA)

17. Make a comparison beteen tow SARS genomic sequence USA 29727nt Canada 29736nt GenBankAY278554

18. attachment engulfenment lost envelope early protein synthesis nucleotide synthesis later protein synthesis encapisula assemble release

19. Human coronaviruses surivival time 229E---6 days in suspension 3 hours after drying on surfaces OC43---<1hour after drying on surfaces SARS virus---4-5 days on drying plastic film 5 days in excrements 10 days in urine 15 days in blood

20. Extinct Cov High tempreture 56c 90min or 75c 30min Ultraviolet 30 min Other disinfectants handling effectively

21. Comparison of previously 3 groups CoV • Phylogenetic analysis of the predicted viral proteins indicates that the virus does not closely resemble any of the three previously known groups of CoVs Cov are divided into three serotypes, The SARS virus is the fouth ?

24. The purpose of studying genome sequence • The genome sequence will aid in the diagnosis of SARS virus infection in humans and potential animal hosts (using PCR and immunological tests), in the development of antivirals (including neutralizing antibodies), and in the identification of putative epitopes for vaccine development.

25. About metapneumovirus • In addition, a novel coronavirus was isolated from vero cell cultures of SARS patiens and metapneumovirus was also identified . Futher studies are currently being completed to help determine whether the human metapneumovirus and novel coronavirus, either alone or in combination ,are the cause of SARS or whether other thus far undetected pathogens are possibly responsible .The possibility that coinfection of either virus with another agent may be responsible for SARS cannot be excluded.

26. Conclusion • SARS virus(coronavirus), a single-stranded plus sense RNA. • SARS virus are stable but a few variforms • SARS virus has long period survival • The genome sequencing of the virus has been finished • Different from previously found coronaviruses. • The largest enveloped virus is difficult to be cultured in vitro. • May be the animals sources?----fruit fox

27. 2. Pathology Severe exudate and tansudate inflammation congestion,edema and formation of hyline membrane

29. highly reactive blood vessels (Cap) Capillary highly dilatation and congestion RBC transudation Virus inclusion

30. syncytial giant cells pneumonia Scanty interstitial inflammatory-cell infiltrates

31. Multinucleated syncytial giant cells and abundant foamy macrophages,no conspicuous viral inclusions in lung of SARS patient

33. Special staining for virus Diffuse alveolar damage with proliferation of Alveolar epithelial typeⅡ Virus inclusion (Macchiavell staining )

34. Immunohistochemical staining of SARS-associated Cov-infected cells Immunoalkline phosphatase with napthol-fast red substrate and hematoxylin counterstain (FAF X250)

35. The immuno-fluorescent staining for virus

37. Lung solidification

38. diffuse alveolar damage and no infection evidence Intraalveolar and interstitial mononuclar cells suggesting a possible viral cause were also noted , but no viral inclusion were seen .

39. Lesions in other organs Multifocal hemorrhage and necrosis Proliferation of histocytes in the surrounding tissue phagocytosis of histocytes

40. Conclusion 1. Diffuse alveolar damage 2. Severe exudate and tansudate but no infection evidence in lung 3. Proliferation of Alveolar epithelial typeⅡ 4. Syncytial giant cells pneumonia 5. Hyline membrane formation 6. Lung solidification 7. The main cause of death is the progressing respiratory failure caused by lung damaging, which also have relationships with immuno-pathological change of the patients.

41. 3. Clinical Features 1. Epidemiology (contact and influential area) 2. Symptoms and signs (fever, dry cough ,myolgia , diarrhea and the number of viruses in sputum is >100M/ml) 3. Laboratory tests: WBC↓,LC ↓ (CD4+ ↓,CD8+↓) 4. X-ray: patches and confluent air-space opacification 5. No effective to antibiotics，partially effective to hormone.

43. X-rayappearance

46. X-rayappearance

47. SARS has spread rapidly becouse during the incubation period , which appears to be between 1 day and 11 days.With a median of about 5 days, patients can transmit the disorder to others.

48. The statistical data of WHO appear the mortabity rate : age mortabity rate <24 year-old <1% 25-44year-old 6% 45-64 year-old 15% >65 year-old >50%

49. Review X-ray appearance of 15 SARS cases

50. Case 1 : 29 year old symptomatic female with normal radiographic appearance