Kagadi, Uganda (CNN) -- The hospital at the center of an Ebola outbreak in Uganda is now dealing with 30 suspected cases, including five from Kibaale prison, Dr. Dan Kyamanywa said Thursday.
Three patients at Kagadi hospital have been confirmed as having the virus, said Kyamanywa, a district health officer.
Doctors are now testing the suspected cases urgently so they can separate confirmed cases from those who do not have the disease, Doctors Without Borders said.
Suspected cases are still trickling into the hospital, Kyamanywa said.
At least 16 people have died in the current outbreak.
The five prisoners have been showing Ebola-like symptoms of vomiting, diarrhea and fever, the doctor said.
"We do expect the number of suspected cases to increase," he said. "It's important to break transmission and reduce the number of contacts that suspected cases have."
There is a fear that the outbreak will spread to the capital, but it is unlikely, he said.
Many patients fled Kagadi hospital when Ebola was confirmed, he said, and the hospital is struggling to respond to all the call-outs to suspected cases.
"Right now there is no treatment for Ebola, so the most effective measure we can take is to contain the spread of the disease," said Olimpia de la Rosa, the Doctors Without Borders emergency coordinator for Uganda Ebola intervention.
"That is why we need to start working immediately. Other cases need to be rapidly identified because containment is what can stop it," said the expert from the aid group, which is also known as Medecins Sans Frontieres.
The Ugandan government has asked people in western Uganda to travel by public transport only if it is necessary.
The outbreak began in the Kibaale district in western Uganda.
The deaths have stoked heightened fear about the spread of the virus, a highly infectious, often fatal agent spread through direct contact with bodily fluids. Symptoms can include fever, vomiting, diarrhea, abdominal pain, headache, a measles-like rash, red eyes and, at times, bleeding from body openings.
Market day was canceled Wednesday after Uganda's president warned people not to gather in large groups.
Health officials urged the public to report any suspected cases, to avoid contact with anyone infected and to wear gloves and masks while disinfecting bedding and clothing of infected people. Officials also advised avoiding public gatherings in the affected district.
Teams in Uganda are taking an aggressive approach, including trying to track down anyone who came into contact with patients infected with the virus and health workers have been gearing up for better protection of health workers and an influx of cases.
The workers include people from Uganda's ministry of health, the U.S. Centers for Disease Control and Prevention and the World Health Organization.
The outbreak initially went undetected because patients did not show typical symptoms, Ugandan Health Minister Dr. Christine Ondoa told CNN on Sunday. Patients had fevers and were vomiting, but did not show other typical symptoms, such as hemorrhaging.
Diagnosis in an individual who has only recently been infected can be difficult since early symptoms, such as red eyes and skin rash, are seen more frequently in patients who have more common diseases, the CDC said.
Uganda's Ministry of Health declared the outbreak in Kibaale district Saturday after the Uganda Virus Research Institute identified the disease as the Sudan strain of Ebola hemorrhagic fever.
The Ebola virus was first detected in 1976 in the central African nation of Zaire (now the Democratic Republic of the Congo). The virus is named after a river in that country. There are five strains of Ebola viruses, all named after the areas where they were found: Zaire, Sudan, Cote d'Ivoire, Bundibugyo and Reston, according to the WHO.