Asia SARS Outbreak 2003

The Pathogen

SARS (Severe Acute Respiratory Syndrome) is an acute respiratory disease. The causative agent of SARS is a previously unknown species of the coronavirus. Sequencing of the SARS virus has shown that it differs from the previously known groups of coronaviruses in nucleotide sequence by 50-60%. The results of sequencing the virus conducted by the Chinese scientists differ significantly from those obtained by Canadian and American researchers, suggesting that the virus possesses an ability to mutate rapidly. Coronavirus is rather unstable, being immediately killed by heating it to 56°C, or under the influence of disinfectants. However, there is evidence of higher stability of the SARS virus. On the plastic surface, the virus may persist for up to 2 days while, in sewage waters, up to 4 days. However, within this period, the number of viral particles is constantly falling. It is possible to suggest that the SARS virus appeared as the result of mutations of the previously known coronavirus species.

The disease is transmitted via airborne droplets and dust. In order for a virus to enter the body, one must be at a distance of not more than 10 cm from its source. In addition, the virus can live outside the body for some time, so contamination through the belongings of the patient, as well as objects, which he/she used, is also possible (Ahuja and Ooi 11).

The SARS Virus

Effect on the Body

SARS has an incubation period of 2-5 days and, according to some estimates, up to 10-14 days (Ahuja and Ooi 10). The main symptom of SARS is profuse serous rhinitis. Body temperature is normal or low-grade. The duration of the disease is up to 7 days. The first symptoms of SARS are chills, headache, muscle pain, weakness, dizziness, and fever up to 38°C and above. This febrile phase lasts for 3-7 days (Ahuja and Ooi 9).

The respiratory symptoms of atypical pneumonia, such as sore throat are not typical. Most patients have a mild form of the disease, and they recover within 1-2 weeks. Other patients develop acute respiratory distress within a week, which includes dyspnea and hypoxemia (Ahuja and Ooi 9).

In addition to the above symptoms, there also can be a cough, runny nose, and the point mucosal hyperemia of the posterior pharyngeal wall. Nausea, vomiting, and abdominal pain are also possible. After 3-7 days, the disease enters the respiratory phase, which is characterized by repeated fever periods, the appearance of persistent nonproductive cough, and difficulty breathing. The examination reveals pallor, cyanosis of the lips and nail plates, tachycardia, muted tones of the heart, and a tendency to hypotension. In 80-90% of cases, the condition improves within a week, symptoms of respiratory failure regress, and recovery occurs. In 10-20% of cases, the condition progressively worsens and symptoms similar to acute respiratory distress syndrome are developed. Death occurs as a result of respiratory failure (Ahuja and Ooi 9).

The Outbreak

The disease was first reported in November 2002 in Guangdong Province, China (Brookes 12). Measures to prevent the spread of the epidemic were not accepted immediately as the Chinese government at first tried to hide the outbreak of this disease in the country. However, the epidemic quickly spread to neighboring Hong Kong and Vietnam, in late February 2003, and later on to other countries and continents. The first recorded case of SARS was reported in Hanoi on February 26, 2003 (Brookes 47).

The severity of symptoms, high mortality, and the possibility of infection of the hospital staff caused great anxiety of the world community, and on March 12, 2003, the World Health Organization (WHO) issued a global alert about the need to stop the spread of this disease. Tourists were advised not to travel to Southern China. According to WHO, during the epidemic, 8436 cases of SARS and more than 900 deaths were registered in 30 countries, with the largest number of victims reported in Mainland China (348 cases) and Hong Kong (298 cases). Casualties also took place in Singapore, Canada, Taiwan, Vietnam, Malaysia, Thailand, and the Philippines (World Health Organization n.p.).

The source of the outbreak was unknown until recently, and the idea of animals being a source of the disease was considered irrelevant. However, the latest researches showed that animals, particularly bats, were the carriers of the disease. According to researchers from the U.S., Australia, and China, viruses similar to the SARS coronavirus were previously detected in the area of bats living in China, Europe, and Africa; earlier, however, bats were not considered a direct precursor of the virus due to lack of evidence. However, the latest results provide strong evidence that these mammals are the source of the SARS coronavirus. Peter Daszak of EcoHealth Alliance, New York, and his colleagues tracked the colony of Chinese red horseshoe bats (Rhinolophus sinicus) in the Yunnan Province during the 12-month period and found two coronaviruses, which were close relatives of the SARS coronavirus as they were tropic to the same receptor (ACE2) in the human body (EcoHealth Alliance n.p.).

In recent years, molecular biologists have found evidence that the SARS virus may be associated with coronaviruses that live in the body of bats, but some scientists have doubted this assertion. Group of Daszak could dispel these doubts by finding a special strain of the “bat” coronavirus SL-CoV-WIV1 in feces of one of the residents of the caves in Southern China. According to scientists, the genome of the virus is similar to that of the SARS virus by 99% and this pathogen is able to infect human and bat cells using the same mechanisms as the causative agent of SARS. Furthermore, human antibodies to the SARS virus are successfully able to neutralize the “bat” coronavirus, which means close kinship between these pathogens (EcoHealth Alliance n.p.).

WHO has developed the basic principles of the infection prevention: the prohibition to visit regions adverse against the infection; strict anti-epidemic control over individuals returning from regions adverse against the infection, the use of a single application of individual masks in case of a need to contact with people suspicious for the development of infection. Through the use of restrictive measures and the establishment of the protective regime, the international community achieved the first victory over SARS. In 2003, the World Health Organization officially declared the end of the SARS epidemic (Brookes 223).