SEOUL, May 29-- The number of South Koreans infected with Middle East Respiratory Syndrome (MERS) increased to nine Friday, just nine days after the first case was reported, the Health Ministry and Welfare said.

Eight other patients were all infected from the patient zero in his late 60s, raising possibility for the first patient to be a " super spreader" who disproportionately infects more people than others.

Two new cases were confirmed as the deadly viral disease, including a nurse who treated the first patient and a male who was hospitalized at the same ward with the patient zero, according to the health ministry.

The eighth case was the 30-year-old nurse who contacted the patient zero. She had initially tested negative Tuesday, but a separate test confirmed her contraction of the MERS corona virus Thursday.

The ninth patient was a 56-year-old man who was admitted to the same hospital ward with the first patient.

The number of infectees rose rapidly to nine just nine days after the first case was confirmed on May 20.

The first patient was an unidentified 68-year-old male who traveled to the Middle Eastern region before returning to South Korea on May 4. His wife became the second patient who contracted the deadly virus.

The third infectee was a 76-year-old man who shared a hospital room with the first patient, and his daughter who attended to the third patient became the fourth.

The doctor, who examined the patient zero earlier this month, became the fifth. The sixth case was a 71-year-old male who was hospitalized at the same ward with the patient zero, and the seventh was a 28-year-old nurse who treated the first patient.

The MERS is a respiratory illness caused by a new type of corona-virus. The first case was detected in Saudi Arabia in 2012. There is no vaccine or treatment for the disease, with its fatality rate reaching 40.7 percent.

The patient zero in South Korea is highly likely to be a host who has a greater contagion than others, called super spreader. One MERS infectee is known to have infected 0.7 people on average, but the super spreader has already infected eight people.

No tertiary infection case has been reported yet as all the eight people were infected with the MERS after having direct or indirect contacts with the patient zero.

South Korea vowed best efforts to prevent the further spread of the viral disease as well as the tertiary infection.

The government on Friday launched the headquarters for central management and prevention for MERS headed by Director-General for Public Health Kwon Joon-wook, a vice ministerial-level official of the health ministry.

Health Minister Moon Hyung-pyo convened the first meeting of the headquarters, saying the ministry will commit all possible resources to prevent the MERS spreading. The minister instructed officials to conduct an epidemiological survey once again to find possibly missed infectees.

Meanwhile, a 44-year-old man, suspected of being infected with the MERS as he had close contacts with the third and fourth patients, left for China Tuesday for a business trip. He is the son of the third patient and the brother of the fourth infectee.

The South Korean authorities notified the Chinese side and the World Health Organization (WHO) of his departure to make the suspected infectee subject to examination and treatment.

The South Korean man did not tell the health authorities that he visited his father during the initial epidemiological survey.

The man saw a doctor on Monday after having a fever, and the doctor recommended he refrain from going for a business trip to China. But, the man left for China Tuesday, neglecting the recommendation.

The doctor failed to report the suspected case to the health authorities Monday, giving a belated notification on Wednesday.

To prevent contagion, a total of 42 people, including his family, co-workers and medical staffs who contacted with him, have been quarantined.

The list of passengers on board the same flight bound for Hong Kong and seated near him was forwarded to the Chinese authorities. Aboard the flight were 80 South Koreans, 73 Chinese, five foreigners and eight crew members.

After arriving in Hong Kong on Tuesday, the suspected man traveled to China's southern Guangdong province by bus on the same day.