Corona viruses and types and diseases caused .pptx

Corona Viruses

1. Corona viruses PRESENTER : DR.NAVEEN.K MODERATOR : DR.PRAVEEN (SENIOR RESIDENT)

2. OVERVIEW INTRODUCTION CLASSIFICATION EPIDEMIOLOGY PATHOGENESIS CLINICAL FEATURES DIAGNOSIS TREATMENT RECENT OUTBREAKS AND UPDATES

3. Introduction Corona viruses derive their name from the characteristic surface projections of spike protein giving crown like appearance. They cause upto 15% of common colds and may also cause croup,asthma exacerbations, bronchiolitis and pneumonia Corona viruses that cause endemics in humans are: HCoV 229E, HCoV NL63, HCoV OC63 , HCoV HKU1.

4. SARS(severe acute respiratory syndrome) and MERS(middle east respiratory syndrome) are novel corona viruses outbreaks during 2003 and 2017 respectively These are enveloped viruses of medium to large size(80-220nm), they possess largest known single stranded positive sense RNA genomes

5. These viruses encode the protein nsp14-Exon which is first known RNA proofreading enzyme responsible for evolution of large corona virus genome complex. Corona viruses received international attention during SARS outbreak which was responsible for more than 800 deaths in 30 countries

6. classification T axonomical classification Alpha corona viruses: HCoV 229E, HCoV NL63 Beta corona viruses: 1.lineage A: HCoV OC43,HCoV-HKU1 2.lineage B: SARS- CoV 3.lineage C and D : exclusively for bat corona viruses, but MERS- CoV also included. Gamma and delta corona viruses: exclusively for non human pathogens

7. Epidemiology Seroprevalence studies have demonstrated that antibodies against 229E and oc43 increase rapidly during early childhood Although some degree of strain specific protection may be afforded by recent infection , reinfections may occur despite the presence of strain specific antibodies Infection rates are peak during winter

8. Outbreak of SARS CoV was during 2003 in guandong province in southern china Serological evidence of exposure in food handlers in the same market suggest these markets facilitate the spread of this virus Its outbreak causes nearly 800 deaths in 30 countries

9. Outbreak of MERS- CoV was during 2017 WHO recorded nearly 2000 cases with nearly 700 deaths(35% of deaths ) First case of MERS during its outbreak noted in saudi arabia in a man with acute pneumonia and renal failure

10. Route of transmission 1. OC43 and 229E: respiratory route through droplet spread 2. SARS- CoV : transmission occurred through direct or indirect contact of mucous membranes with infectious droplets or fomites, animal to human transmission is through cats

11. Feco oral route of transmission is also seen in SARS- CoV 3. MERS- CoV : transmission mainly through contact with respiratory secretions of camels and possibly with raw camel products ( eg : unpasteurized milk) although human to human transmission noted it is less communicable compared to other strains

12. Pathogenesis of SARS and MERS Severe disease in SARS and MERS is due to direct virologic damage followed by immunopathology Studies with SARS- CoV in human airway epithelial cell cultures indicate that ciliate cells are principal targets for infection, whereas MERS- CoV preferentially infects bronchial epithelial cells type1 an 2pneumocytes and vascular endotheium

13. Clinical manifestations Respiratory infections: cold symptoms are indistinguishable from other viruses like rhinoviruses,adeno viruses and other respiratory viruses Rhinorrhea , cough , sore throat, malaise, headache are most common symptoms, fever seen in 60% of cases NL63 causes croup in children less than 3 years

14. 2.Non respiratory sequelae : They lead to gastroentiritis characterized by diarrhea , bloody stools, abdominal distension,bilious gastric aspirate and classic necrotising enterocolitis have also been documented in corona virus infection . These viruses are well known causes for neurologic diseases in animals including demyelinating encephalitis

15. SARS- CoV The incubation period ranged from 1-14 days Clinical manifestations are non specific consists of fever,coryza , cough,malaise,chills , rigors and headache Coryza is most common in children whereas syestimic manifestations are seen in teenagers

16. Gastrointestinal symptoms like diarrhea and nausea or vomitings occurred in up to 1/3 rd of the cases Adults were most severely affected Acute renal failure with with histologic acute tubular necrosis was present in 6.9% of patients 28.8% of SARS patients had abnormal urinalysis Case fatality rate was 10-17%,no pediatric deaths were reported

17. MERS- CoV The incubation period is approximately 10 days Patients presented with acute respiratory infection,fever,cough,pneumonia and ARDS. Lymphopenia,neutrophilia and late thrombocytopenia occurred index case patient

18. Some patients had progressive renal impairment Case fatality rate is >65% , most patients have been adults although children as young as 1yr of age have been infected

19. DIAGNOSIS PCR primers for corona viruses in multiplex RT-PCR is widely used Virus cultures for primary clinical specimens for human corona virus HKU1,NL63,OC63,229E are used SARS- CoV and MERS- CoV can successfully be grown in culture from respiratory samples

20. Serodiagnosis with complement fixation,neutralisation , hemagglutination inhibition, enzyme immunoassay and western blots are used in research setting For all endemic and emerging HCoVs nasopharyngeal swabs or aspirates are most likely to be positive, but in a setting of possible novel corona virus, serum or stool may be positive.

21. Two highly sensitive real time RT-PCR are currently available for testing MERS- CoV in addition to utilizing immunoflorescence microscopy for detection of antibody response

22. TREATMENT There is no available antiviral agents for clinical use against corona viruses Treatment for SARS- CoV and MERS- CoV is primarily supportive, in diagnosed patients individual should be isolated and treated. Ribavarin was extensively used during 2003 outbreak of SARS but its efficacy was not prooved and invitro studies shows poor efficacy Systemic corticosteroids are associated with temporary clinical improvement in some patients

23. Interferon-alpha was associated with more rapid resolution of oxygen requirements Human monoclonal antibodies derived from SARS patients could be potentially therapeutic There no effective vaccine for corona viruses Vaccine trails are being done on surface spike protein

24. RECENT OUTBREAKS and UPDATES Outbreak of novel corona virus occurred in china , presently virus is called as nCoV-2019 1 st case was recognised in wuhan province in china in seafood handler in seafood market The first case might have acquired disease from snakes It is believed to be spread through human to human transmission Initial all cases linked to huanan seafood market in wuhan , it was closed in 01/01/2020

25. Suspect Severe acute respiratory infection (SARI) in a person, with history of fever and cough requiring admission to hospital, with no other etiology that fully explains the clinical presentation AND any of the following: A history of travel to China in the 14 days prior to symptom onset; OR The person develops an unusual or unexpected clinical course, especially sudden deterioration despite appropriate treatment, without regard to place of residence or history of travel.

26. Probable A person with acute respiratory illness of any degree of severity who, within 14 days before onset of illness, had any of the following exposures : a . Close physical contact with a confirmed case of nCoV infection, while was symptomatic ; OR b. A healthcare facility in a country where hospital associated nCoV infections have been reported; OR c. direct contact with animals in countries where the nCoV is known to be circulating in animal populations or where human infections have occurred as a result of presumed zoonotic transmission .

27. Reference Nelson textbook of pediatrics 20 th edition WHO china update novel corona virus CDC update for novel corona virus 2019 IAP update on nCoV 2019

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