A Vista resident was hospitalized with a case of dengue, the second case of the mosquito-transmitted illness in San Diego County, health officials said Friday. The first case, which occurred earlier this month in Escondido, is not related to the second case, according to a statement from the San Diego County Health Department. The Vista resident had not recently traveled to a place where the illness is common, the statement said. “As always, the county is closely monitoring these recent cases of locally acquired dengue and quickly responding to prevent the spread of illness,” said Dr. Seema Shah, county interim deputy health officer. “While the risk of getting dengue continues to remain low, we are paying attention to increases in cases of dengue in California and across the U.S.” Dengue, which is not commonly found in the U.S., is a tropical viral disease that can be acquired through mosquito bites to people who travel to countries where dengue is common. Fever, chills, nausea, vomiting and rash are symptoms of dengue, which can be determined by a blood test. The county vector control is in Vista Friday through Tuesday to treat about 60 homes. Technicians will apply a pesticide approved by the Environmental Protection Agency, AquaDuet, to reduce the number of adult mosquitoes, officials said. Invasive Aedes mosquitoes were first detected in the county in 2014, and this year there have been 53 cases of travel-related dengue here.