The Tokyo Metropolitan Government said Thursday that the dengue virus was detected again in mosquitoes collected in Tokyo's Yoyogi Park on Tuesday and Wednesday.
The virus was first confirmed in mosquitoes there last week.
Of the 20 locations checked by the metropolitan government, the dengue virus was detected in four traps on the east side of the park. In testing carried out on Sept. 2 and 3, the virus was detected mostly in the park's west side.
Most of Yoyogi Park has been closed since Sept. 4, and the metro government plans to continue spraying pesticide there, officials said.
On Wednesday, health minister Yasuhisa Shiozaki said he would consider submitting a bill to the Diet this fall to strengthen the inspection system for infectious diseases.
"Infectious diseases are now worldwide problems. It is an important to take measures against them," Shiozaki told reporters after a visit to the National Institute of Infectious Diseases in Shinjuku Ward, which has been analyzing the dengue outbreak.
Meanwhile, the Japan Sumo Association announced Wednesday it would take preventive measures against dengue fever in preparation for the fall tournament that starts Sunday at the Ryogoku Kokugikan arena in Sumida Ward, Tokyo.
The association plans to spray pesticide to expel mosquitoes on the premises, which features trees and shrubbery.
"We decided to take a proactive measure so that the audience can enjoy the matches without worry," said Tamanoi, a deputy manager of public relations for the association who goes by one name.