References:
- Global Infectious Diseases and Epidemiology Online Network: Infectious Diseases of the Philippines, 2013 eBook Edition, ISBN 978-1-61755-582-4, by Stephen Berger. Accessed here.
| Agent | Virus - RNA. Coronaviridae, Coronavirus |
| Reservoir | Human Bat Civet Cat |
| Vector | None |
| Vehicle | Droplet Fecal-oral (questionable) |
| Incubation Period | 3 to 5 days (As early or late as 2 to 23 days) |
| Diagnostic Tests | Identification of virus through PCR and direct immunofluorescence Serology (ELISA) |
| Typical Adult Therapy | Supportive. Isolation (respiratory and other secretions). |
| Typical Pediatric Therapy | As for adult |
| Clinical Hints | Exposure to endemic area or patient; fever (>38 C), cough, respiratory difficulty, headache, myalgia, diarrhea, hepatic dysfunction, CPK elevation, thrombocytopenia. Case-fatality rate 10.9% |
| Synonyms | Human coronavirus Erasmus Medical Centre, London1 novel CoV 2012, Novel CoV 2012, SARG, Severe Acute Respiratory Syndrome, Sindroma Respiratoria Aguda, Sindrome respiratorio agudo grave, SRA, SRAS, Syndrome Respiratoire Aigu Severe. |
Clinical Case Definition for SARS
A person with a history of:
- Fever (≥38°C)
- AND One or more symptoms of lower respiratory tract illness (cough, difficulty breathing, shortness of breath)
- AND Radiographic evidence of lung infiltrates consistent with pneumonia or RDS; OR autopsy findings consistent with the pathology of pneumonia or RDS without an identifiable cause.
- AND No alternative diagnosis can fully explain the illness.
The Laboratory case definition of SARS is as follows: A person with symptoms and signs that are clinically suggestive of SARS AND with positive laboratory findings for SARS-CoV based on one or more of the following diagnostic criteria:
- PCR positive for SARS-CoV. PCR positive using a validated method from:
- At least two different clinical specimens (e.g. nasopharyngeal and stool)
- OR The same clinical specimen collected on two or more occasions during the course of the illness (e.g. sequential nasopharyngeal aspirates)
- OR Two different assays or repeat PCR using a new RNA extract from the original clinical sample on each occasion of testing.
- Seroconversion by ELISA or IFA
- Negative antibody test on acute serum followed by positive antibody test on convalescent phase serum tested in parallel
- OR Fourfold or greater rise in antibody titer between acute and convalescent phase sera tested in parallel.
- Virus isolation
- Isolation in cell culture of SARS-CoV from any specimen AND PCR confirmation using a validated method.
Acute Infection
The incubation period is generally 3 to 5 days, with a range of 2 to 10 days.
- Most patients complain of headache, sore throat, myalgia and chills.
- Additional findings reported in some patients include rhinorrhea, chest pain, diarrhea, abdominal pain, vomiting and confusion.
- Initial reports described isolated instances of “rash.”
- Lymphocytopenia, neutrophilia or neutropenia, thrombocytopenia, and elevations of CPK and hepatic transaminase levels are common.
- Rhabdomyolysis and renal failure were reported in some patients.
After 3 to 7 days, lower respiratory symptoms occur, particularly a dry, nonproductive cough which may be accompanied by hypoxemia.
- Features of ‘atypical pneumonia’ develop on the fourth to fifth days of illness.
- Ten to twenty percent of patients described to date have developed signs of adult respiratory distress syndrome.
- Chest roentgenograms reveal generalized interstitial or patchy infiltrates, with areas of consolidation in a few cases.
- Sub-clinical and non-pneumonic infections are reported.
Complications
The overall case-fatality rate is 10.9%; but as high as 50% among those who develop severe respiratory illness.
- Multi-organ dysfunction (bowel, liver, kidney) may occur in severe cases. 23
- Risk factors for mortality include age >60 years, history of contact with SARS patients within 2 weeks prior to illness onset, health occupation, inferior hospital ranking and longer interval to seeking medical care (longer than 1 day).
- Advanced age, leucocytosis, detectable virus in nasopharyngeal aspirates (PCR) and elevated serum lactic dehydrogenase (LDH) levels have been associated with a poor prognosis.
- The disease appears to be milder among young children.
- Some studies have suggested that concurrent infection by human metapneumoviruses or orthoreoviruses are associated with more severe illness and poor prognosis.
- Nearly 60% of survivors experienced psychiatric disorders (mainly PTSD or depression)