The Dallas Ebola case was inevitable, given the size of the epidemic raging in West Africa and the ease of modern air travel, infectious diseases specialists say.
Indeed, many told 麻豆传媒, the longer the African epidemic lasts the more likely such cases become, not only in the U.S,. but in other developed countries.
But the risk to the general public in the U.S. and the likelihood of a wide outbreak are vanishingly small, the experts agreed.
The man, who flew from Liberia Sept. 19 and arrived in Dallas Sept. 20, is currently in intensive care and isolated at , after being admitted Sept. 28. He was described as critically ill when the case was announced Sept. 30.
The Dallas case is a "serious problem but it does not pose a significant risk to the general public," according to , of the University of Washington in Seattle and a spokesman for the
The case shows that healthcare systems need to be "alert and prepared" for Ebola, Duchin told 麻豆传媒. But Duchin and all other experts reached by 麻豆传媒 agreed that most systems have already made appropriate preparations.
"Healthcare facilities, knowing that such a case was probable, have been preparing their staff to accurately screen for risk of Ebola ... and isolate any suspect cases immediately," commented , of the University of Arizona Health Network and College of Medicine in Tucson.
"Hospitals and public health entities in the U.S. are largely prepared for an occurrence such as this and have many more resources available than in West Africa," commented , of Wake Forest Baptist Medical Center in Winston-Salem, N.C.
"A wide epidemic in the U.S. is extremely unlikely," he told 麻豆传媒 by email.
'Hiccups' in Process
But several experts commented on what one called "hiccups" in the case that raise questions about how well those preparations are being implemented.
After landing in Dallas, the unidentified man developed symptoms Sept. 26 and sought care at Texas Health Presbyterian, according to the CDC, but was sent home. He returned 2 days later and was admitted, tested for Ebola, and found to be infected.
The hospital system has not explained the 2-day gap and did not respond to a call from 麻豆传媒 seeking clarification.
"It's not surprising that it happened, but it's not excusable," commented , a critical care specialist at the University of Pittsburgh Medical Center and also an IDSA spokesman.
The problem is that the early symptoms of Ebola are nonspecific and might not trigger an alarm in a busy clinician, Adalja told 麻豆传媒. He said that a travel history -- if one was taken, which is not clear -- should have raised a red flag.
Taking such a history is essential and should be considered as important as asking about allergies before prescribing antibiotics, he said. "The weakest link in the chain is that we have to ask people where they've been," he added.
Epidemiologist Rossi Hassad, PhD, of in New York City concurred: "It is troubling that amidst heightened awareness about the Ebola virus and enhanced hospital assessment protocols, a patient with Ebola-related symptoms and a history of travel from Liberia was not readily considered a suspected case of Ebola," he told 麻豆传媒 by email.
"This must not be repeated, as it may prove costly," he argued.
"It was inevitable to have someone arrive who was exposed, but not yet ill," commented of the University of Texas School of Public Health in Brownsville.
"The question is why a travel history was not taken when he was first seen 2 days before he was admitted to the hospital," McCormick, who was an investigator during the first Ebola outbreak in 1976, told 麻豆传媒 by email.
'Crucial time'
"This cost (the patient) crucial time for treatment and provided added opportunity for transmission," McCormick added.
There's an justifiable expectation that this case -- and any in the future -- can be contained, commented MPH, of Georgetown University Medical Center in Washington D.C., and a former chief scientist at the FDA.
Yet the apparent lapse underlines the need to avoid overconfidence, he told 麻豆传媒 by email.
"While much of the response so far seems exemplary, we don't know why the disease was not recognized when he first sought care," he said. "We don't know if a travel history, one of our most basic but important diagnostic tools, was obtained and testing considered then."
"If indications and protocols for testing were followed, and this patient was not tested, then those protocols should be re-evaluated," Goodman said.
The Ebola outbreak has been raging in West Africa for several months, after it was first recognized in March.
In the three hardest-hit countries -- Guinea, Liberia, and Sierra Leone -- the virus has caused 7,157 infections and 3,330 deaths, according to the latest situation report from the , although the numbers are widely seen as an underestimate.
As well, Senegal has had a single imported case and no deaths while Nigeria has had 20 cases and eight deaths after a man with the virus flew from Liberia to Lagos -- an event similar to the Dallas case.
In both countries, despite limited medical and public health resources, health officials were able to prevent widespread disease, commented , of the SUNY Downstate Medical Center in Brooklyn.
'Imports inevitable'
Imported cases of Ebola were inevitable, Imperato said, but a widespread outbreak is "unlikely" because healthcare and public health systems are better than they are in Africa.
"The forward risk of transmission from this index case has now been reduced to virtually zero since the patient was hospitalized in isolation conditions in a tertiary care medical facility," he said.
It's possible that some people were infected in the gap between the onset of symptoms and the patient's isolation at Texas Health Presbyterian, according to , of the University of Alabama at Birmingham.
Since public health officials are tracking down the man's contacts, the chain of transmission is unlikely to go any further, Wilson told 麻豆传媒 in an email.
"If there were an outbreak," he said, "it is unlikely to go beyond one layer of exposure before processes and procedures would be initiated" to bring it to a halt.
He too cited the Nigerian case, noting that the country managed to halt its outbreak with medical infrastructure that is not on "the level of infrastructure and processes/procedures we have here."
It would be unwise to rule out a wider outbreak, commented the University of Arizona's Elliott, noting "there are no 'absolutes' in medicine."
But he, like others, argued that healthcare providers are on the lookout for contacts of the Dallas patient and appear to have sufficient resources to find, monitor, and isolate them if that become necessary.
As well, the actual ability to isolate patients "is not difficult to achieve in the U.S.," he said.
Several experts noted that the incubation period of Ebola is too long to rule out further imported cases.
Exit screening in the three countries involves simply checking for fever, commented , of Saint Louis University. "If no fever is detected, the subject is allowed to travel," he said in an email.
But the incubation period of Ebola can be as long as 21 days and "obviously there are up to 21 days after the exit screening when somebody already infected could get sick," Hoft said.
People with Ebola aren't infectious until the become symptomatic, so passengers on the aircraft that brought the man to Dallas are not at risk and neither are those he might have had contact with in Dallas Forth Worth Airport, Elliott said.
"You need to have direct contact with secretions (blood, vomit, stool, sweat) from a sick person," Hoft said, "so the risk in the Texas case is thought to be limited to the ER staff who saw the patient with early symptoms and didn't think to ask of travel history and the family contacts."
Other comments
, of MedStar Washington Hospital Center in Washington, D.C.:
"This occurrence was anticipated, as the outbreak in West Africa involves thousands of patients, and air-travel to the U.S. continues. The risk of onward transmission is extremely low, as Ebola requires contact with infected body fluids in a patient who has a fever. Similarly, the medical assets and social dynamics in the U.S. make a wider epidemic unlikely. A sick patient in the U.S. will be cared for in a fully-equipped hospital, where trained staff have access to gloves, gowns, and masks to prevent the spread of infection."
, of the University of Wisconsin in Madison:
A wider epidemic in the U.S, is "highly unlikely at this point (but) possible if other countries start seeing a lot of cases in which case triaging by travel will become a challenge." But the risk of onward transmission from this case is "very, very low given the extensive infrastructure and public health resources in the U.S."
, of University Hospitals Case Medical Center in Cleveland:
"It is such a large outbreak and travel is so easy and fast and the incubation period can be up to 3 weeks, so (an imported case) was bound to happen. The larger this outbreak is and the longer it goes on, the more patients we will see with Ebola virus outside of West Africa, (but) a wider epidemic would be really hard to picture in the U.S."
, of Duke University:
"A simple review of the escalating numbers of infections and travel patterns to and from the U.S. shows we had to be prepared for this, (but) a wider epidemic remains very unlikely in the U.S., although individual cases like this remain a possibility we need to all prepare for."
, of Albert Einstein College of Medicine in New York City:
This is "not the first time we have had a filovirus-infected individual in the U.S. whose infection was diagnosed here" (with Lassa fever, for instance). A wider outbreak is "not impossible, but appears unlikely. In order for this to occur, we would need a significant influx of infected individuals and the unmonitored proliferation of chains of viral transmission."
, of the University of Miami Miller School of Medicine:
The case "is not a surprise to anyone who has been following the growing epidemic in West Africa ... in the mind of many, this was inevitable. Ebola in its current form is not easily transmissible, and it is highly unlikely that we will see more than the occasional traveler who is infected and, possibly, the occasional family member or other person who has been in contact with a patient prior to him or her seeking medical care."
of NYU Langone Medical Center in New York City:
"The most important step in the care of an infected patient is to provide supportive therapy -- management of fluids and electrolytes. There is intense interest in novel antivirals and vaccines -- but the efficacy of these modalities is unproven. In addition, immediate implementation of appropriate infection prevention measures is critical, followed by the public health response -- especially investigative steps to identify anyone that could have potentially been exposed, and then carefully monitor them over the next 21 days, the absolute maximum incubation period for Ebola. If these standard infection control protocols are implemented and managed effectively, the risk of further spreading of Ebola outside of this particular situation is essentially eliminated."
of Texas Children's Hospital in Houston:
"The fact that Ebola has entered the U.S. is not a surprise, but a key point is that we have the isolation facilities and the ability to trace contacts in order to ensure that an Ebola outbreak will not happen in Dallas or Texas."
of the Nebraska Medical Center in Omaha:
"Given the escalating Ebola epidemic in Africa, the number of U.S. citizens going to Africa to assist, and the frequency of global air travel — this was bound to happen."
of the UCLA School of Public Health:
"It is much harder to get than the common cold or the flu and is only spread through contact with bodily fluids of infected individuals who are symptomatic. It is significantly less contagious than the Middle East Respiratory Syndrome (MERS), which recently arrived in the U.S. but was rapidly contained with no secondary infections."
, of the Mayo Clinic in Rochester, Minn.:
"There may be some secondary cases who were direct contacts of the known Ebola patient. However, because of our robust public health infrastructure, it is highly unlikely that the outbreak would extend beyond that."
, of the Massachusetts General Hospital in Boston:
"Hospitals have, based on guidance from the [CDC], developed new plans or enhanced existing plans for identifying and managing such patients, even though the likelihood of encountering such a patient at an individual hospital remains very low.”