West African Ebola – what is the true Case Fatality Rate?
Paul Conton, MSEE
Up until this year the largest Ebola
outbreak the world had witnessed was in Uganda, centered around the
town of Gulu. By the time the outbreak was eventually contained, some
425 patients had been infected with the virus, of whom 224 died (Case
Fatality Ratio = 53%). Are there lessons we can draw from the Ugandan
experience in this West African outbreak? How were the Ugandans able to
defeat Ebola? What mistakes did they make and what worked well?
Uganda was fortunate (or, depending on your point of view, sufficiently
vigilant) that the outbreak was for the most part contained in the
district of Gulu, which experienced 93% of the cases. It did spread to
two other areas but was quickly contained there. In Gulu it was more
difficult, and at one point appeared to be out of control. One of the
best accounts of the Uganda outbreak (xxx) tells the story of Dr Mathew
Lukwiya, who became famous for his handling of the emergency in Gulu;
he is credited with the early diagnosis of Ebola, which was then an
unknown disease in Uganda, and with quick institution of an isolation
ward, thus preventing the spread of the disease to other areas. This
notwithstanding, many of the features that we see here in West Africa,
were very much present in Gulu. The denial, the association with
witchcraft, the fear, the infection of hospital workers and near
breakdown of the health care system.
How was the disease contained? It's unclear from the accounts whether
any one factor can be credited with the ending of the outbreak in Gulu.
According to WHO's Epidemiology of Gulu Ebola
Yes, Dr Mathew worked heroically in his hospital, but at the end of it
all Dr yyy, who worked in another hospital in Gulu had this to say,
" ". Contact tracing
and quarantining certainly played a role. There is some talk of the
disease burning itself out, although the precise mechanism of this is
unclear. Certainly in West Africa we see no evidence of this at this
Health workers were frequently struck down by Ebola in Gulu, to the
point that the hospitals were almost overwhelmed. There were at least
two approaches to this problem. Dr Mathew used his hospital staff
exclusively to treat patients and towards the end they nearly rebelled
against him. In other hospitals, doctors encouraged a spouse or
family member to be the primary caregiver for each patient. Wearing
protective clothing, caregivers cooked for and cleaned up after their
loved ones. The system reduced risks for nurses and nursing assistants,
keeping them away from infectious body fluids.
"There is no right answer to the question of how to nurse Ebola
patients in Africa," said Dr. Daniel Bausch, a C.D.C. medical
epidemiologist who worked in northern Uganda last fall and managed the
Ebola ward at a small government hospital in Gulu town. In many African
hospitals, it is less a matter of best medical opinion than of what is
possible. Dr. Bausch used family caregivers on the Ebola ward at Gulu
Hospital because he said he had no reasonable alternative.
Whatever its medical or epidemiological value, Dr. Matthew's system
became a management nightmare. He tried to reassure nurses and nursing
assistants that the risk was tolerable. Yet as the weeks
went by, Ebola insidiously eroded his authority.
Health-care workers wore their protective gear, they managed their risks and still they got sick. Twelve of them died.
Dr yyy used patient relatives to do much of the caring and thus spared
his staff. Apparently there is some divergence in the medical community
on this. There has also been talk of using Ebola survivors for some of
the caring, as Ebola survivors at least theoretically have immunity and
will never again get the disease. This would take some of the pressure
off trained health workers. Much of the duties with Ebola care involve
cleaning and assistance that do not require trained health personnel.
If these routine duties could be undertaken by other, non-health
personnel, it would free the health personnel for strictly medical
It may be that by the process of natural selection the virus gets more
and more deadly with each new outbreak. The organisms that thrive and
multiply are the ones that are best able to mutate and adapt to their
new environment. And because the replication rate is so rapid, mutation
can occur in a relatively short space of time.
octors who treat Ebola are not convinced that they have a whole lot to
offer any patient. They estimate that using IV drips to replace lost
fluids might make a difference for about 10 percent of those who get
sick. For others, they guess, the seriousness of the illness depends on
the genetic makeup of a patient, the amount of tainted blood or other
body fluid that has come in contact with a patient and the route of
infection. The prick of a bloody syringe, for example, is almost
certainly worse than a cough in the face.
"Ebola is a tough disease," Dr. Bausch said. "I am not so sure that
once someone is infected that the treatment we offer prevents more
people from dying than would have died anyhow.