Identify the characteristics of SARS which account for its spread and the severity

carefully read the following WHO Update and the information presented from the Armed Forces Institute of Pathology and prepare a characterization of the disease based on the characteristics of infectious diseases and viruses presented in this course.

For this case assignment please complete the following tasks:

Carefully review the material presented below on SARS.

Identify the characteristics of SARS which account for its spread and the severity.

Briefly justify your reasons for selecting the characteristics of SARS as described above.

State your opinion as to which characteristic is the most significant factor that causes people to worry and cancel their travel plans.

World Health Organization

Severe Acute Respiratory Syndrome (SARS)-multi-country outbreak – Update 47

Studies of SARS virus survival, situation in China

5 May 2003

Disease Outbreak Reported

Scientists in the WHO network of collaborating laboratories yesterday reported results of the first scientific studies designed to determine the survival time of the SARS virus in different environmental media. Results from studies of the effectiveness of different disinfectants commonly used in hospitals were also reported, confirming the validity of currently recommended measures for infection control.

The new studies, conducted at network labs in Hong Kong, Japan, and Germany confirm, as anticipated, that the SARS virus can survive after drying on plastic surfaces for up to 48 hours. Ongoing studies are testing virus stability on additional surfaces, with initial results expected by Wednesday.

Scientists have also tested virus survival times in faeces. Research conducted at one Hong Kong lab determined that the virus can survive in faeces for at least 2 days, and in urine for at least 24 hours. Studies conducted at a second Hong Kong lab found that virus in faeces taken from patients suffering from diarrhoea, which has a lower acidity than normal stools, could survive for 4 days. This raises the possibility that surfaces contaminated with faeces from patients suffering from diarrhoea might survive for as long as 4 days. However, the dose of virus needed to cause infection remains unknown. Further studies are needed before firm conclusions about the role of faecal-oral transmission can be made.

Results of the new studies underscore the need for frequent handwashing, proper cleaning, and good disinfection control in hospitals managing SARS cases. Spread by infected droplets remains the most important mode of transmission. Good personal hygiene, including frequent handwashing, is important for everyone in areas with SARS cases, but most especially so for persons who have been in close contact with a probable case.

Shedding of the SARS virus in faeces, respiratory secretions, and urine is now well-established. In Hong Kong in late March, a large and sudden cluster of more than 320 simultaneous cases occurred among residents of the Amoy Gardens housing estate. The outbreak raised the possibility of an environmental source of infection. Subsequent investigations suggested that contamination with sewage might have played a role. Around 66% of Amoy Gardens SARS patients presented with diarrhoea as a symptom, compared with 2% to 7% of cases in other outbreaks. With the exception of the Amoy Gardens cluster and a previous event where cases were linked to visits to a single floor of a hotel, SARS is thought to spread in the majority of cases through close person-to-person exposure to infected droplets expelled during coughing or sneezing.

All previous speculation about the environmental behaviour of the SARS virus was based on knowledge about other well-known human members of the Coronavirus family, which cause illnesses such as the common cold. WHO has been concerned that the SARS virus, which is unlike any other human or animal virus in its family, might behave differently. Studies now under way in the network laboratories will support the further development and implementation of virus-specific infection control measures. WHO remains concerned that the SARS virus continues to be transmitted to hospital staff in highly advanced settings where sophisticated infection control measures are in place.

Situation in China
Chinese authorities reported 160 new probable cases of SARS and 9 new deaths. The new figures bring the cumulative total in China to 4280 probable cases and 206 deaths. Of the new cases, 98 were reported in Beijing. The second highest number of new cases was reported in Shanxi. Three of the 9 deaths occurred in Beijing, 3 in Guangdong, 2 in Shanxi, and 1 in Tianjin.

The new figures bring the cumulative total in China to 4280 probable cases and 206 deaths. China now accounts for 65% of the worldâ€™s total cumulative number of probable SARS cases and 44% of all reported deaths.

In Beijing, some 16,000 residents remain under quarantine. In Taiyuan, the capital of Shanxi Province, where 360 probable SARS cases have been reported, all schools are to be closed indefinitely.

WHO officials are particularly concerned about the SARS situation in Chinaâ€™s outer provinces, where surveillance and reporting systems may not be sufficiently sensitive to detect all suspect and probable cases. In resource-poor regions like Gansu and Jiangxi, serious questions remain about the capacity of the health systems to cope with a challenge on the scale of SARS.

Update on cases and countries
As of May 5th, 2003, a cumulative total of 6583 probable SARS cases with 461 deaths have been reported from 27 countries.

Severe Acute Respiratory Syndrome (SARS)-multi-country outbreak – Update 47

Studies of SARS virus survival, situation in China

5 May 2003

Disease Outbreak Reported

In Beijing, some 16,000 residents remain under quarantine. In Taiyuan, the capital of Shanxi Province, where 360 probable SARS cases have been reported, all schools are to be closed indefinitely.

Update on cases and countries
As of May 5th, 2003, a cumulative total of 6583 probable SARS cases with 461 deaths have been reported from 27 countries.

Source: The Armed Forces Institute of Pathology

Negative stain electron micrograph of coronavirus isolated from a SARS patient. Bar represents 100nm. (Contributed by Charles Humphrey, PhD, and Anthony Sanchez, PhD, National Centers for Disease Control and Prevention)

Source: The Armed Forces Institute of Pathology
The SARS Pathogen

The world was first alerted to the existence of SARS in Hanoi, Vietnam, by the WHO scientist Dr. Carlo Urbani. He died from the disease in Bangkok on March 29, 2003. The worldwide outbreak of SARS was traced to a single ill health care worker from Guangdong Province, China. Working in conjunction with 13 laboratories from 10 countries, the WHO reported a coronavirus, never seen before in humans, as the cause of SARS.

The image above was obtained from virus isolated, purified, and concentrated in cell culture. The characteristic petal-shaped projections are not present all virus particles thus making identification difficult.

SARS is a recently described respiratory illness that has been reported in Asia, Europe, and North America. The incubation period is typically 2 to 7 days with cases ranging up to 10 days. Fever, usually greater than 100.4 F, heralds the onset of illness and may be accompanied by chills, malaise, headache, and myalgias giving an overall flu-like picture. Lower respiratory symptoms including cough, shortness of breath, and dyspnea may develop after the initial incubation period, and can progress to hypoxemia severe enough to require mechanical ventilation. The illness follows a variable course with death in approximately 5% of individuals.

For more information go to: Armed Forces Institute of Pathology at http://www.afip.org/hot-topics/SARS/

Your assignment is due by the Monday following the end of this Module. Please upload your case assignment to CourseNet.

Case Assignment Expectations

Length: Case Assignment Module assignments should be at least 2-4 pages (400-800 words) in length.

References: At least two references should be included from academic sources (e.g. peer-reviewed journal articles). Required readings are included. Quoted material should not exceed 10% of the total paper (since the focus of these assignments is critical thinking). Use your own words and build on the ideas of others. When material is copied verbatim from external sources, it MUST be enclosed in quotes. The references should be cited within the text and also listed at the end of the assignment in the References section (preferably in APA format).

Organization: Subheadings should be used to organize your paper according to question

Format: APA format is recommended (but not required) for this assignment. See Syllabus page for more information on APA format.

Grammar and Spelling: While no points are deducted, assignments are expected to adhere to standards guidelines of grammar, spelling, punctuation, and sentence syntax. Points may be deducted if grammar and spelling impact clarity.

The following items will be assessed in particular:

Relevance (e.g. all content is connected to the question)
Precision (e.g. specific question is addressed. Statements, facts, and statistics are specific and accurate).
Depth of discussion (e.g. present and integrate points that lead to deeper issues)
Breadth (e.g. multiple perspectives and references, multiple issues/factors considered)
Evidence (e.g. points are well-supported with facts, statistics and references)
Logic (e.g. presented discussion makes sense, conclusions are logically supported by premises, statements, or factual information)
Clarity (e.g. writing is concise, understandable, and contains sufficient detail or examples)
Objectivity (e.g. avoid use of first person and subjective bias)