Not all hantavirus infections lead to diseases and not all cases are fatal, said Dr. Tran Phu Manh Sieu, director of the Ho Chi Minh City Preventive Health Center.
He was speaking to the media in the wake of a recent human infection in HCMC's District 3.
Sieu said people should not unnecessarily panic, but act swiftly to control rodents that can also spread several other diseases.
On Monday, the Pasteur Institute Ho Chi Minh City announced that it had found the potentially deadly hantavirus among rats caught near the house of the man who became infected with the virus and was successfully treated last month.
Three of 25 rats caught in District 3's Ward 9 tested positive for hantavirus.
According to the US Centers for Disease Control and Prevention, hantavirus found in Asia can cause Hemorrhagic Fever with Renal Syndrome (HFRS), which is fatal 5-15 percent of the time.
People become infected through contact with hantavirus-infected rodents, or their urine and droppings.
On November 8, the HCMC Hospital for Tropical Diseases confirmed that a 55-year-old patient, identified only as T., had contracted hantavirus.
T. was admitted to the hospital with a high fever and skin rashes. Doctors initially diagnosed him with the mosquito-borne dengue fever before administering tests at the Pasteur Institute which showed T. had hantavirus.
Doctors said T. recovered after ten days of treatment and was discharged from the hospital in late October.
T. said he had been bitten by a rat while asleep at home.
The information prompted the Pasteur Institute to conduct tests on 25 rats and house mice collected randomly near his house.
The three samples that tested positive for hantavirus all came from rats, an institute representative said.
According to Dr. Sieu, hantavirus infection is rare and cannot be spread from human to human.
"Over the past decade, Vietnam only recorded three cases of hantavirus infection from rats and none were fatal," he said.
However, Sieu said rats and mice do transmit other diseases such as bubonic plague and tetanus, and that residents should be vaccinated after being bitten by rodents.
Following reports on the recent hantavirus case, many residents told Vietweek about the high number of rats and mice in and around their homes.
Than, a resident of the Apartment 38 Nguyen Van Troi Street in Phu Nhuan District said the rodents have been found in all the complex's units, including those on the sixth floor.
"They have snuck into the bedroom, wardrobe and cupboard. We can't get rid of them all," he said.
Phuong, a 22-year-old student at the dormitory 135B Tran Hung Dao Street in District 1 said the rats sometimes crawl across her face as she sleeps.
Dr. Nguyen Dac Tho, deputy director of the HCMC Preventive Health Center, said his agency had instructed district-level preventive health agencies to issue a report on the spread of rats in order to formulate a plan to control them.
Anyone who has spent any time in HCMC knows there are rats everywhere.
However, Tho said: "There are not many rats at apartments and residential areas where people maintain good hygiene."
Dr. Sieu said discarded food, abundant in HCMC, is the main reason why so many rats and mice exist in the city.
"In homes, discarded food and open trash bins attract the rodents," he said.
He warned that most sewer systems in the city have open manholes without nets that rats can easily come out from to enter residents' homes.
He also said many people continually litter food near manholes and do not care that they are feeding the rats with this bad habit.
"The most effective way to control rats and mice is to eliminate their food source," Sieu concluded.