About 100 people are now being monitored for the Ebola virus, according to health officials, while four family members of the Texas hospital patient diagnosed with the disease were placed under quarantine Wednesday night to stem its potential spread.

Thomas Eric Duncan’s close family members, who spent time with Duncan in an apartment near the north Dallas hospital where he is now battling the virus, received hand-delivered orders from Texas and Dallas County officials not to leave the apartment or to receive visitors without approval until at least Oct. 19, the end of the virus’s 21-day incubation period.

“We have tried and true protocols to protect the public and stop the spread of this disease,” said Dr. David Lakey, the Texas state health commissioner. “This order gives us the ability to monitor the situation in the most meticulous way.”

The number of people being monitored for Ebola symptoms swelled overnight as local, state and federal officials scrambled to compile a list of anyone who had immediate or secondary contact with Duncan, the first person to develop Ebola in the United States. None of the people being monitored have exhibited any signs of the virus.

Health officials will use a technique known as contact tracing to identify the circle of people who are potentially at risk. It involves finding everyone who came into close contact with the patient and then interviewing them to identify additional potential contacts, who are subsequently tracked down and interviewed themselves. This form of shoe-leather epidemiology will continue until officials are confident that no one is at risk for contracting or spreading the virus, health officials said.

Compiling a list of possible contacts is the preliminary phase of a technique known as contact tracing. The contact tracing will be carried out by a team of five epidemiologists with the Centers for Disease Control and Prevention (CDC) in concert with county and state health officials. The process involves both phone calls and in-person visits, during which interviews are conducted and possible contacts are provided with information about the virus and informed about best practices to prevent its spread. Health officials will check in with those contacts daily to monitor for symptoms of the virus, which include high fever, severe headache, vomiting and diarrhea.

It is no surprise the tally of possible contacts has grown. Health officials are casting a very wide net, and the number of people on the list of possible contacts is expected to shrink dramatically as the investigation continues and contacts are divided into high-risk, low-risk and no risk categories, health officials said.

It is unclear exactly how many people are being monitored for symptoms of the virus. The Texas Department of State Health Services pegged the number at “about 100.” A second health official with knowledge of the investigation confirmed that figure to TIME. Erikka Neroes, a spokeswoman for Dallas Count Health and Human Services, told TIME that just over 80 people were on the list.

The majority of people being monitored did not necessarily have contact with Duncan himself, but rather with someone who Duncan encountered. “No one is symptomatic as of yet,” Neroes says, “either in the first group or that second group.” Apart from the four family members under quarantine, all the people being monitored are able to move freely. Ebola is not contagious until a person shows symptoms of the virus.

Health officials are not ruling out the possibility that more Ebola cases will emerge, but they say they are confident in their ability to contain the situation. While extremely deadly, Ebola is difficult to transmit. It is communicated through bodily fluids like vomit or blood, but cannot travel through the air.

source: time.com by Alex Altman