The Ebola Virus Disease (EVD), formally known as Ebola Haemorrhagic Fever, has recently been confirmed to be the cause of death for over a thousand people. Most of these deaths occurred in   West African countries, from among almost 2,000 infected as of August 18. Simply put, one out of two people infected by this virus has died till date in the current outbreak.

The Ebola virus can cause hemorrhagic fever in humans and some other primates. This virus has been implicated in other outbreaks in the past too, mostly in Africa. It was first detected in 1976 in the Democratic Republic of Congo. The virus, similar to over 70 percent of human pathogens, has a non-human reservoir. So Ebola is categorised as a zoonotic pathogen (a pathogen that crosses the species barrier and infects another species). Available evidence suggests that in Africa, fruit bats are the main source of the Ebola virus and that the first human infection started from this mammal. There have also been reports of the virus being found in other primates, such as monkeys and chimpanzees, and pigs. However, it has been assumed that all other hosts were infected and do not act as natural hosts for the virus. There has been limited worldwide research carried out on Ebola in terms of basic science and epidemiology. Therefore, available information is still very meagre, compared to other diseases that could turn into an epidemic.

Virus transmission

Until now, all transmission of Ebola to humans has been direct. This means, the virus does not last long enough in the air for it to infect other humans at close proximity. It is instead transmitted through bodily fluids, such as blood and other secretions, or through the handling of infected or dead humans and animals. Bodily fluids left on external surfaces outside the body can support viral survival of up to 48 weeks, unless measures to disinfect such surfaces are taken. Till date, Ebola has not been recorded to be transmitted through food or water.

Ebola affects humans by infecting endothelial cells, which are a layer of our blood vessels, and certain immune cells and also liver cells. Furthermore, it  ‘uses’ some of our immune cell types by disrupting their immune function and using them to transport itself around the body. There is also evidence to suggest that this virus induces the body to produce certain proteins (called cytokines) that hurt the body rather than help it, unlike in normal infections. Ebola virus particles also reproduce very fast, thereby increasing the ability of this virus to overwhelm the human immune system and leading to high rates of death among infected persons.

Aerial transmission is not a major cause for concern for Ebola in natural conditions—unlike other viral outbreaks, such as avian influenza (H5N1) and swine flu (H1N1), although laboratory research has shown that the Ebola virus can travel in water particles in controlled conditions as aerosols. However, the fact that it can spread by contact and bodily fluids, and most importantly, the fact that there exists no curative medication or vaccine against the virus makes this a particularly lethal infection. While avian influenza, with its high mortality rate (kill ing six out of 10 infected persons), could not be transmitted from one infected human to another, Ebola can be transmitted between humans. Thus, Ebola appears to possess the lethality of avian influenza and the capability to transmit among humans. These are some of the major reasons which led the World Health Organisation (WHO) to declare the current outbreak an International Public Health Emergency on August 8.

Diagnosis and treatment

Diagnosis of this disease can be carried out by many methods. The best and most reliable way is virus isolation in laboratories. However, due to the risk posed by the virus, only the highest level of laboratory facilities, called Biosafety Level 4 (BSL 4), is allowed to do this as per WHO requirements. Thus, alternative methods, such as testing for antibodies produced by the body in response to the infection (ELISA) or by direct detection of the viral ribonucleic acid (RNA) by the method of Polymerase Chain Reaction (PCR), have been used worldwide.In terms of treatment, there are few ‘trial’ medications that have been tested on severely ill patients, which have shown some positive outcomes. A few days back, WHO officially ruled out the mass availability of medicines for ‘several months’. So since there is no immediate treatment or vaccine, prevention is currently the best approach to controlling the spread of the disease.

Prevention in Nepal

In Nepal, no Ebola cases have been  detected till date. This is not to say that the virus cannot infect the Nepali population. We are in a position to prevent the entry of the virus by ensuring that surveillance processes start immediately. This includes monitoring of tourist arrivals at airports and at our border posts for those with high fever and symptoms resembling EVD. Since the symptoms of EVD are similar to those of influenza and other developing country diseases (cholera, malaria, typhoid), proper diagnosis should begin immediately after the suspected person in kept in quarantine. Similarly, all surfaces should be regularly disinfected using all available means in highly populated places. While dealing with a suspect case, a certain distance should be maintained, and gloves along with masks (if close contact is required) should be worn. Washing one’s hands with soap and using hand sanitisers are some ways to prevent infection in health-care settings. However, air travel is not considered as risky in Ebola transmission, as in avian influenza epidemic.

As Ebola is a communicable disease and it can kill easily, we should take extreme precautions. Luckily, simple safeguards can ensure that humans do not get infected with the disease. The thrust, however, is in ensuring such precautions are taken seriously. In Nepal, now is a good time to increase the alert level and intercept the virus before it is able to reach the inland population. The Epidemiology Division of the Ministry of Health and Population has already started important steps in this regard, which is a welcome sign. These and similar initiatives must be continued with until WHO lowers its alert level for the outbreak.

Dixit is the Director of Research at Center for Molecular Dynamics Nepal (@sameermdixit)