Medicos are more at risk of SARS than common man

By Dr Vasant G Shenoy -

A mysterious highly infectious acute respiratory killer disease of viral chlamydeal etiology causing an atypical pneumonia like presentation and originating in China and South East Asia has created panic waves that has impacted inspite of the savage and fiery war between US lead allies and Iraq. The World Health Organisation has issued a rare global "Red Alert" due to this epidemic.

Problem Statement

The Severe Acute Respiratory Syndrome (SARS) is a newly identified clinical illness linked to an outbreak of atypical pneumonia in Guangdong province of China since November 2002. The spread to Hongkong is linked to a visitor from this province, who travelled to Hong Kong in spite his sickness and stayed at a hotel during late February 2003. This index case is considered responsible for further spread in Hong Kong and then to Singapore, Vietnam, Canada, Ireland, the US and Germany. So far the case fatality rate is about 3.59 per cent, out of which almost two thirds are medical and para-medical persons including one researcher. It is medical and para-medical staff who is more affected than the common man.

Definition

For Public Health Surveillance purpose, WHO defined SARS as follows :- A person presenting after February 1, 2003 with a history of High Fever (> 38°c) and one or more respiratory symptoms including cough, shortness of breath, difficulty in breathing and one or more of the following :-

• Close contact within 10 days of onset of symptoms with a person who has been diagnosed with SARS.
• History of travel within 10 days of onset of symptoms to an area in which there are reported foci of transmission of SARS. i.e. upto April 1, 2003 - Canada, Singapore, China (including Hongkong), Taiwan, Vietnam etc. Here close contact means having cared for, having lived with or having had direct contact with respiratory secretions and body fluids of a person with SARS.

Agent Factor

The pathogen responsible for SARS has not yet been detected. However, the Centre for Disease Control and other major laboratories have been able to identify a new variant of Corona virus as the possible cause - so called due to a "halo" or "crown" like appearance under microscope. It is known to survive upto three hours in the environment. Chinese experts believe it to be a chlamydial disease.

Host Factors

• Age- Most cases have occurred in previously healthy adults of 25 - 70 years of age. Few cases have occurred in children under 16 years of age.
• Occupation - Since it spreads by close contact, in the earlier phase this underestimated killer disease spread like wild fire in medical and para-medical workers. In fact, two thirds of victims are from this group. Also at high risk are immediate family members and friends of a SARS case.
• International Travel - Human mobility by way of international travel is an important factor in the wide spread of this infection to about 17 countries so far.

Environmental Factors

Since overcrowding favours spread of this highly infectious disease, Indian health authorities are naturally worried about massive spread of this disease should it enter India.

Modes of transmission

• Droplet Transmission :- Droplets containing micro organisms are propelled a short distance of 1 - 2 metres through the air and infect via eyes, nose or mouth. These droplets are generated by sneezing, coughing, talking etc. as well as procedures like nebulisation, bronchoscopy, gastroscopy, suction etc.
• Contact Transmission :- Either direct close contact or indirect contact through contaminated surfaces, fomites etc. can spread the disease.
• Aerosol Transmission :- It appears uncommon if it occurs at all.
• Incubation Period is 2 - 10 days after exposure to virus. It can be as much as 13 - 14 days.

Clinical features

A patient of SARS may present with initial symptoms of - Fever more than 38°c. - Headache and Bodyache - Generalised feeling of discomfort. After 2 - 7 days, patient develops non - productive cough and breathlessness. Patient may become alright or may develop hypoxia and around 10 - 20 per cent patients may require ventilatory support. Patient may develop cynosis. There may be CNS related problems like altered mentation, convulsions etc. due to hypoxia.

Investigations

• WBC counts - Low l Platelet counts- Low l Liver function tests.- Abnormal
• Renal function Tests- Normal l Arterial blood gas to know levels of hypoxia l X-Ray chest may show small hilar or focal interstitial infiltrates in early stage - progressing to more generalized patchy interstitial infiltrates.

Treatment

• Complete isolation.
• Total bed rest.
• Oxygen or ventilatory support as per arterial blood gas reports.
• Fluid replacement.
• Antibiotic therapy that will cover the common causative organisms as in serious community acquired pneumonia or atypical pneumonia. Prophylactic antibiotics should also be used to prevent secondary bacterial infection.
• Anti-viral agents like Ribavarin have been used with varying success in severe cases.
• Steroids - In severe cases, steroids are used with good results.
• Therapies/ interventions which may cause aerosolisation of respiratory of respiratory secretions such as nebulised bronchodalators, bronchoscopy, gastrascopy, etc are to be avoided strictly.

Special instructions

• Clinical samples are collected by hospital staff and not by laboratory staff.
• Strict barrier nursing techniques and universal precautions are observed in sample collection and processing.
• All material used is disposed of by incineration.
• To preserve the bacterial viability or viral integrity in specimen, specimen is placed in appropriate media and stored at recommended temperature.
• For respiratory samples and frozen tissues - 70°c.
• For serum 4 - 8°c for 24 - 48 hours and -20°c for longer periods.
• To handle this yet unknown pathogen, a Bio-Safety Level-3 (BSL-3) is used. If this is not available, use a Bio-Safety Level-2 (BSL-2) physical facility using BSL-3 practices.

Prevention

• Isolation or qurantine as soon as a patient is suspected to have SARS. He should be isolated at home or an institution depending upon his general condition and be kept under observation for 14 days.
• Prevention of transmission of infection from the patient is achieved with the help of masks and disposable gowns and avoidance of unnecessary contact.
• Healthcare workers should encourage patients for selfcare.
• Extensive and proper use of personal protection equipments (PPE) like surgical masks, gloves and disposable gowns etc. are prescribed for all who are in close proximity of the patient. Health care workers must use fresh PPE for every new patient. All used PPE. must be sealed in appropriate disposal bags and incinerated or decontaminated.
• Do not manage suspected case in the same room as probable cases.
• Central A/C should be turned off to prevent spread to other patients.
• Visits by family members and non - essential staff should be avoided as far as possible.
• Separate sets of PPE patient care devices like tourniquets, tubings etc. must be restricted to each patient. Strict disinfection and disposal standards must be maintained by the staff.
• Patient should be transported on the same principles of isolation, mask on patient, full PPE for staff, minimal contact, strict hygiene, complete disinfection of all transport and other equipments. At community level, a sensitive and effective surveillance system should be in place for identification of SARS cases to allow isolation and strict barrier nursing to limit local spread. A system should be developed for verifying and confirming / dispelling rumours about SARS cases.

(The author is member, special task force of government of Maharashtra to combat SARS)