![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
rfmcdonaldThe CBC reported on the first discovery of a case of Ebola in the United States, in this case of someone of Liberian background in Texas who contracted the virus on a recent trip to his homeland.
National Geographic went into more detail, mentioning that the patient was initially released from hospital when he first appeared.
Wired suggested panic about a general spread in the United States was unwarranted.
National Geographic also noted that hospitals had been preparing to handle Ebola cases for some time.
MacLean's noted that Canada is also preparing.
Scientific American, meanwhile, noted that because of the nature of the virus and the way it spreads, it is very unlikely that Ebola will become airborne.
Top health officials have confirmed the first case of Ebola diagnosed in the United States, saying a patient who recently travelled to Liberia has the disease and is being treated in isolation at a Texas hospital.
[. . .]
Edward Goodman, an epidemiologist at Texas Health Presbyterian Hospital in Dallas, said Tuesday the patient is ill and being seen by "highly trained, competent specialists" under intensive care.
[. . .]
According to Dr. Thomas Frieden, director of the U.S. Centers for Disease Control, the patient left Liberia on Sept. 19 and arrived in the U.S. the next day.
Ebola symptoms can include fever, muscle pain, vomiting and bleeding, and can appear as long as 21 days after exposure to the virus. The disease is not contagious until symptoms begin, and it takes close contact with bodily fluids to spread.
The patient had "no symptoms" when leaving Liberia or entering the U.S., but began to develop symptoms around Sept. 24. Two days later the patient sought care, Frieden said, and was admitted to hospital on Sunday.
National Geographic went into more detail, mentioning that the patient was initially released from hospital when he first appeared.
The patient had recently arrived in the U.S. from Liberia and was confirmed to be infected on Tuesday. He reportedly told officials at Texas Health Presbyterian Hospital of his recent travels when he went to an emergency department for care last week. He was sent home but was readmitted on Sunday, much sicker.
[. . .]
It's hard to identify Ebola in its early stages because the initial symptoms of the disease—fever, diarrhea, vomiting, and aches—are the same as for many other illnesses, including malaria, which is also common in West Africa.
That's why the Dallas patient was able to leave Liberia on September 19 without any indication that he would soon be ravaged by Ebola. The West African nations where the virus is raging are supposed to test outgoing passengers for fever, to make sure that no one with Ebola symptoms gets on a plane and spreads the disease.
[. . .]
The people who came into close contact with the Dallas patient while he was sick, from September 24 until he was isolated in a hospital room on September 28, are at risk for the virus.
Public health officials are tracking 12 to 18 people in Dallas who had contact with the patient, including 5 children who have been asked to stay home from school. Medical personnel plan to check their temperature twice a day and to look out for other symptoms.
Wired suggested panic about a general spread in the United States was unwarranted.
There is little risk of the disease spreading widely in the U.S., Frieden said. Unlike highly contagious airborne pathogens like influenza, the Ebola virus requires contact with bodily fluids such as urine, saliva, feces, vomit, or semen to be transmitted. The risk is highest for people in direct contact with patients—typically healthcare workers and family members. In Africa, the lack of treatment centers and supplies has hampered efforts to contain the virus. But in the U.S., hospitals are better stocked and have better isolation facilities. In addition, public health officials have well-tested strategies to prevent the spread of infectious diseases. “This kind of contact tracing is core public health, it’s what we do day in and day out,” Frieden said.
[. . .]
The patient came to the U.S. to visit family members who are citizens and was not known to be participating in any aid efforts for Ebola patients in Liberia before coming here, Frieden said. The patient left Liberia on a plane the 19th, arrived in the U.S. on the 20th, and became symptomatic on the 24th or 25th, Frieden said. The patient sought medical care on the 26th, but was not admitted to the hospital until the 28th. Asked about that discrepancy, Frieden noted that the symptoms of Ebola, which include fever, severe headache, and muscle pain overlap with symptoms of many other infections. He added that the CDC is urging physicians to ask patients with these symptoms about their travel history.
“It is certainly possible that someone who had contact with this individual, a family member or other individual, could develop Ebola in coming weeks, but there is no doubt in my mind we will stop it there,” Frieden said.
National Geographic also noted that hospitals had been preparing to handle Ebola cases for some time.
American hospitals have been preparing since midsummer for the possibility of having to care for an Ebola patient, but Tuesday's news took the development out of the theoretical realm. Since then, there have been 12 false alarms—patients suspected of having Ebola who did not have the disease, the CDC said.
"It was virtual before," said Belinda Ostrowsky, an infectious disease expert at the Albert Einstein College of Medicine and Montefiore Medical Center in New York City. "Now it's happened, so it just makes us that much more vigilant."
The CDC has been advising hospitals for several months to prepare for patients with Ebola, though each hospital is preparing slightly differently.
At Texas Health Presbyterian Hospital, staff ran a drill last week to prepare for possible patients, according to the hospital's epidemiologist, Edward Goodman.
At Montefiore, signs in the emergency department ask patients to let caregivers know if they've recently traveled to the West African nations of Liberia, Sierra Leone, or Guinea.
MacLean's noted that Canada is also preparing.
Canada is considering placing doses of an experimental Ebola vaccine in hospitals around the country that have been designated to treat Ebola cases if any arrive in the country, the new chief public health officer said Wednesday.
Dr. Gregory Taylor said having vaccine at the ready means it could be used if health-care workers treating Ebola patients had risky exposures.
“We’re considering prepositioning some of that at receiving hospitals across the country who may be looking after Ebola patients. This is for the health-care workers,” Taylor said during a news conference held in Banff, Alta., where the federal, provincial and territorial health ministers met Wednesday.
Taylor said that includes the Ontario hospital that has been designated to care for Canadian responders if any become infected in the Ebola zone and are transferred back to Canada for care. He did not mention the hospital by name, but it is Toronto Western.
To date, that need has not arisen.
Scientific American, meanwhile, noted that because of the nature of the virus and the way it spreads, it is very unlikely that Ebola will become airborne.
Here is what it would take for it to become a real airborne risk: First off, a substantial amount of Ebola virus would need to start replicating in cells that reside in the throat, the bronchial tubes and possibly in the lungs. Second, the airborne method would have to be so much more efficient than the current extremely efficient means of transmission that it would overcome any genetic costs to the virus stemming from the mutation itself. Substantial natural hurdles make it unlikely that either event will occur.
Currently, Ebola typically gains entry into the body through breaks in the skin, the watery fluid around the eye or the moist tissues of the nose or mouth. Then it infects various cells of the immune system, which it tricks into making more copies of itself. The end result: a massive attack on the blood vessels, not the respiratory system.
Even viruses that are well adapted to attacking the respiratory system often have a hard time getting transmitted through the airways. Consider the experience so far with avian flu, which is easily transmitted through the air in birds but hasn’t yet mutated to become easily spreadable in that fashion among people.
What's the hold-up? “The difficulty is that those [flu] viruses don’t have the protein attachments that can actually attach to cells in the upper airway. They have to develop attachments to do that,” Schaffner says. So even if a virus were exhaled, it would need to lodge onto something in another person’s cells that are already prepared for it in the upper airway. “Since the virus doesn’t have attachment factors that can work in the upper airway, it’s very rare for it to go human to human, and then it almost always stops and doesn’t get to a third person,” Schaffner notes. Similarly for Ebola, the virus would have to develop attachments that would allow it to easily attach receptors in the upper respiratory pathway—something that neither it (nor any of its viral cousins) has been known to do in the wild.
And yet Ebola already spreads very easily without such mutations. The delicate lock-and-key protein–virus fit required for the virus to successfully latch onto and replicate in the airway has not developed because there is no evolutionary pressure for it to do so; it simply would not be an efficient option. Epidemiologists can take some comfort in that.
Tags:
