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What is Ebola and why does it spread?

AfricaDiseases and IllnessesEbola
So, what is Ebola virus, anyway, and how does it spread?
Ebola: One of mankind's deadliest and most brutal diseases
Those who have observed Ebola have described the process, horrifically, as watching human beings 'dissolve.'

For scientists tracking the deadly Ebola virus in West Africa, it is not about complex virology and genotyping, but about how contagious microbes - like humans - use planes, bikes and taxis to spread.

Tracing every person who may have had contact with an infected case is vital to getting on top of the outbreak within West Africa, and doing so often means teasing out seemingly routine information about victims' lives.

So far, the disease has claimed over 3,300 lives, making it the deadliest outbreak in history. 

What is Ebola?

Ebola virus disease (also known as Ebola hemorrhagic fever), along with being one of mankind's deadliest diseases, is also one of its most brutal. It causes extreme body aches, high fever, profuse vomiting, diarrhea and heavy internal and external bleeding, sometimes through body orifices and the pores of the skin.

Doctors and journalists who have observed those dying of Ebola have described the process, horrifically, as watching human beings "dissolve."

Symptoms can manifest themselves between two and 21 days after exposure and usually begin with headaches and fever. There is no cure for the disease, which has been fatal in up to 90 percent of patients during some outbreaks, though the current outbreak has killed about 50 percent of those so far infected. 

According the the World Health Organization, treatments include managing the patient's fluids and electrolytes, as well as blood pressure and kidney function, all of which are in jeopardy as the infected bleed out of organs and even blood vessels.

Transmission of the virus occurs when a person comes into contact with the bodily fluids - blood, vomit, feces - of one who is infected. This puts health workers tending to Ebola patients in an extremely dangerous position as patients can throw off huge amounts of their fluids during uncontrollable fits of pain and vomiting. Walls, sheets and medical equipment can become soaked in the highly infectious substances. Patients are kept in isolation to avoid infecting others in a clinical setting. 

Even with the full body suits health workers wear - the iconic image of the disease - transmissions still occur. Several American missionaries working to disinfect doctors and nurses operating in suits have contracted Ebola and the chief doctor fighting the outbreak in Sierra Leone, Dr. Sheik Umar Khan, recently caught the virus while treating others and died.

The first diagnosed case of the Ebola Zaire strain was a nurse who perished after treating a nun who broke with Ebola after helping treat the sick in then Zaire, now the Democratic Republic of Congo.

There are five known strains of Ebola, which first manifested itself in humans in the 1976 in Sudan and in a village in Zaire near the Ebola River, from which the disease draws its name. Four of the five have caused disease in humans, while the fifth, Ebola Reston, caused disease only in primates. The Reston strain is named for Reston, Virginia where the strain was discovered in a commercial monkey house in 1989. It killed hundreds of monkeys, and many more were euthanized, but never made the jump to human beings.

The outbreak spreads

The West Africa outbreak, which began in Guinea in February, has already spread to Liberia and Sierra Leone. It is the largest since the Ebola virus was discovered almost 40 years ago.

Some in the nations effected by Ebola are distrustful of of authorities battling the disease, thinking it might be caused by those treating it, or that traditional medicinal methods will be better than jam-packed isolation wards - sometimes quite literally - dripping with the virus.

One Ebola victim was broken out of a Freetown hospital by her family and eventually died after turning herself back in to health authorities. 

Protests broke out in Sierra Leone outside one hospital with an isolation ward last week. Assistant Inspector General Alfred Karrow-Kamara said the protest was sparked by a former nurse who had told a crowd at a nearby fish market that, "Ebola was unreal and a gimmick aimed at carrying out cannibalistic rituals."

In southeastern Guinea, a delegation of government officials, doctors and journalists were pelted with stones and beaten when they arrived to help educate and treat villagers. Eigh members of the delegation were killed in the attack.

Richard Haba ,a local cop, said the villagers believed that Ebola “is nothing more than an invention of white people to kill black people."

The belief among some that families or traditional medical practices can provide better care than trained doctors puts families at high risk of contracting the disease and it's not uncommon for several members of the same family, or even large portions of an entire village, to contract the virus as a result. 

The first case

Epidemiologists and virus experts believe the original case in that instance to have been a woman who went to a market in Guinea and then returned, unwell, to her home village in neighboring northern Liberia.

The woman's sister cared for her, and in doing so contracted the Ebola virus herself before her sibling died of the hemorrhagic fever it causes.

Feeling unwell and fearing a similar fate, the sister wanted to see her husband - an internal migrant worker then employed on the other side of Liberia at the Firestone rubber plantation.

She took a communal taxi via Liberia's capital Monrovia, exposing five other people to the virus who later contracted and died of Ebola. In Monrovia, she switched to a motorcycle, riding pillion with a young man who agreed to take her to the plantation and whom health authorities were subsequently desperate to trace.

Gatherer noted that while Ebola does not spread through the air and is not considered "super infectious", cross-border human travel can easily help it on its way. "It's one of the reasons why we get this churn of infections," he said.

In previous outbreaks, Ebola often "burned out," sadly killing populations quickly in isolated areas before human carriers had great opportunity to spread it. Better transportation and communication throughout West Africa means the virus has spread more quickly and more easily. 

Patients are at the most dangerous when Ebola is in its terminal stages when bleeding and vomiting are at their heaviest.

Anyone at this stage of the illness is close to death, and probably also too ill to travel, said Bruce Hirsch, an infectious diseases expert at North Shore University Hospital in New York.

"It is possible, of course, for a person to think he might just be coming down with the flu, and to get onto transport and then develop more critical illness. That's one of the things we are concerned about," he said in a telephone interview.

-Reuters, the Los Angeles Times and Charlie J. Johnson, Chicago Tribune staff

Copyright © 2014, The Baltimore Sun
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