Ebola Virus Disease Update

1.0 INTRODUCTION
Ebola virus disease (EVD), also known as Ebola hemorrhagic fever (EHF) or simply Ebola, is a viral hemorrhagic fever of humans and other primates caused by ebolaviruses. EbolaVD is a severe, highly infectious and often fatal illness. It is a viral haemorrhagic fever caused by Ebolavirus genus, FiloviridaeFamily (Filovirus). The Zaire ebolavirus is the most dangerous species of this genus and has been responsible for most of the outbreaks so far, including the 2014 one. EVD has an average fatality rate of around 50%, but case fatality rates have varied from 25% to 90% in past outbreaks. Signs and symptoms typically start between two days and three weeks after contracting the virus with a fever, sore throat, muscular pain, and headaches. Then, vomiting, diarrhea and rash usually follow, along with decreased function of the liver and kidneys. At this time some people begin to bleed both internally and externally (WHO, 2014). The disease has a high risk of death, killing between 25 and 90 percent of those infected, with an average of about 50 percent. This is often due to low blood pressure from fluid loss, and typically follows six to sixteen days after symptoms appear (Ruzek, 2014).
Ebola first appeared in 1976 in two simultaneous outbreaks, in Nzara, Sudan, and in Yambuku, Democratic Republic of Congo (Isaacson et al., 1976; WHO, 2012).The latter was in a village situated near the Ebola River in Nzara, Sudan, from which the disease takes its name. It has not been reported in humans in the Asia Pacific region as of 31 July 2012. However, with global travel, it is possible that outbreaks in Africa could result in the spread of the virus to Asia (Olivalet al., 2013).
There are different species of the Ebola virus. Of these, the Reston ebolavirus was first discovered in laboratories in Reston, Virginia, United States of America (USA) in 1989 after some quarantined, crab-eating macaque monkeys originating from the Philippines became ill and died. In 2008, a virus identified in pigs was found to be very similar to the virus identified in monkeys imported into the USA for research from the Philippines in 1989 (WHO, 2016).
The virus spreads by direct contact with body fluids, such as blood, of infected human or other animals. This may also occur through contact with an item recently contaminated with body fluids (WHO, 2014). Spread of the disease through the air between primates, including humans, has not been documented in either laboratory or natural conditions (CDC, 2015). Semen or breast milk of a person after recovery from EVD may carry the virus for several weeks to months (WHO, 2014; CDC, 2015). Fruit bats are believed to be the normal carrier in nature, able to spread the virus without being affected by it. Other diseases such as malaria, cholera, typhoid fever, meningitis and other viral hemorrhagic fevers may resemble EVD. Blood samples are tested for viral RNA, viral antibodies or for the virus itself to confirm the diagnosis (WHO, 2014).
Control of outbreaks requires coordinated medical services, alongside a certain level of community engagement. The medical services include rapid detection of cases of disease, contact tracing of those who have come into contact with infected individuals, quick access to laboratory services, proper healthcare for those who are infected, and proper disposal of the dead through cremation or buried (WHO, 2014). Samples of body fluids and tissues from people with the disease should be handled with special caution. Prevention includes limiting the spread of disease from infected animals to humans. This may be done by handling potentially infected bush meat only while wearing protective clothing and by thoroughly cooking it before eating. It also includes wearing proper protective clothing and washing of hands when around a person with the disease. No specific treatment or vaccine for the virus is available, although a number of potential treatments are being studied. Supportive efforts, however, improve outcomes (WHO, 2014).

1.1 HISTORY
Ebola virus was first isolated in 1976 during 2 simultaneous outbreaks of Ebola hemorrhagic fever in Yambuku, Democratic Republic of Congo (Zaire) andNzara, Sudan with the highest (50% – 90%) (WHO, 2014; CDC, 2015). The disease was given the name Ebola because of the location of the affected village of Democratic Republic of the Congo (Zaire) on the Ebola River (Ruzek, 2014).
The disease is notifiable or reportable in most Western countries. It is genetically unique zoonotic animal borne, severe and rare disease, which affects human and non-human primate and typically occurs in outbreaks in tropical regions of Sub-Saharan Africa (WHO, 2014). From 1976 to 2013, about 1,000 people / year have been infected. The largest incidence was the 2014 West Africa Ebola outbreak, which is affected Guinea, Sierra Leone, Liberia and Nigeria. As of 12th August 2014 more than 1848 suspected cases with 1176 laboratory confirmed alongwith 1013 deaths have been reported. Between 1976 and 2013, the World Health Organization reported a total of 24 outbreaks involving 1,716 cases (WHO, 2014; 2016). The largest outbreak was the epidemic in West Africa, which occurred from December 2013 to January 2016 with 28,616 cases and 11,310 deaths. It was declared no longer an emergency on 29 March 2016 (CDC, 2014; WHO, 2016).

1.2 EPIDEMIOLOGY/ RECENT UPDATE ON EBOLA VIRUS
The disease typically occurs in outbreaks in tropical regions of Sub-Saharan Africa. From 1976 (when it was first identified) through 2013, the World Health Organization reported 1,716 confirmed cases (CDC, 2014; WHO, 2014). The largest outbreak to date was the Ebola virus epidemic in West Africa, which had caused a large number of deaths in Guinea, Sierra Leone, and Liberia (CDC, 2014).
• Sudan Outbreak: The first known outbreak of EVD was identified only after the fact, occurring between June and November 1976 in Nzara, South Sudan, (and then part of Sudan) and was caused by Sudan virus (SUDV) (Peterson et al., 2004; Hoenenet al., 2012). The Sudan outbreak infected 284 people and killed 151. The first identifiable case in Sudan occurred on 27 June in a storekeeper in a cotton factory in Nzara, who was hospitalized on 30 June and died on 6 July (Feldmann and Geisbert, 2011). Although the WHO medical staff involved in the Sudan outbreak was aware that they were dealing with an unknown disease, the actual “positive identification” process and the naming of the virus did not occur until some months later in the Democratic Republic of the Congo (Piot and Marshall, 2012).
• Zaire Outbreak: On 26 August 1976, a second outbreak of EVD began in Yambuku, a small rural village in Mongala District in northern Zaire (now known as the Democratic Republic of the Congo). This outbreak was caused by EBOV, formerly designated Zaire ebolavirus, which is a different member of the genusEbola virus than in the first Sudan outbreak. The first person infected with the disease was village school headmaster MabaloLokela, who began displaying symptoms on 26 August 1976. Lokela had returned from a trip to Northern Zaire near the Central African Republic border, having visited the Ebola River between 12 and 22 August. He was originally believed to have malaria and was given quinine. However, his symptoms continued to worsen, and he was admitted to Yambuku Mission Hospital on 5 September. Lokela died on 8 September 14 days after he began displaying symptoms (Piot and Marshall, 2012).
Soon after Lokela’s death, others who had been in contact with him also died, and people in the village of Yambuku began to panic. This led the country’s Minister of Health along with Zaire President Mobutu SeseSeko to declare the entire region, including Yambuku and the country’s capital, Kinshasa, a quarantine zone. No one was permitted to enter or leave the area, with roads, waterways, and airfields placed under martial law. Schools, businesses and social organizations were closed (Stimola, 2011). Researchers from the CDC, including Peter Piot, co-discoverer of Ebola, later arrived to assess the effects of the outbreak, observing that “the whole region was in panic (Piot and Marshall, 2012; CDC, 1995). Piot concluded that the Belgian nuns had inadvertently started the epidemic by giving unnecessary vitamin injections to pregnant women, without sterilizing the syringes and needles. The outbreak lasted 26 days, with the quarantine lasting 2 weeks. Among the reasons that researchers speculated caused the disease to disappear, were the precautions taken by locals, the quarantine of the area, and discontinuing the injections (Stimola, 2011).
During this outbreak, Dr. NgoyMushola recorded the first clinical description of EVD in Yambuku, where he wrote the following in his daily log: “The illness is characterized with a high temperature of about 39 °C (102 °F), diarrhea with blood, retrosternal abdominal pain, prostration with ‘heavy’ articulations, and rapid evolution death after a mean of 3 days (Bardi and Jason, 2014).
The virus responsible for the initial outbreak, first thought to be Marburg virus, was later identified as a new type of virus related to marburgviruses. Virus strain samples isolated from both outbreaks were named as the “Ebola virus” after the Ebola River, located near the originally identified viral outbreak site in Zaire (Feldmann and Gilbert, 2011). Reports conflict about who initially coined the name: either Karl Johnson of the American CDC team (Preston and Richard, (1995) or Belgian researchers. Subsequently, a number of other cases were reported, almost all centered on the Yambuku mission hospital or having close contact with another case. 318 cases and 280 deaths (an 88 percent fatality rate) occurred in Zaire. Although it was assumed that the two outbreaks were connected, scientists later realized that they were caused by two distinct ebolaviruses, SUDV and EBOV (Feldmannet al., 2003). The Zaire outbreak was contained with the help of the World Health Organization and transport from the Congolese air force, by quarantining villagers, sterilizing medical equipment, and providing protective clothing.
• 1995 to 2014: The second major outbreak occurred in Zaire (now the Democratic Republic of the Congo) in 1995, affecting 315 and killing 254. In 2000, Uganda had an outbreak affecting 425 and killing 224; in this case, the Sudan virus was found to be the Ebola species responsible for the outbreak (WHO, 2014).In 2003 there was an outbreak in the Republic of the Congo that affected 143 and killed 128, a death rate of 90 percent, the highest death rate of a genusEbola virus outbreak to date.In 2004 a Russian scientist died from Ebola after sticking herself with an infected needle (Formentyet al., 2003).
Between April and August 2007, a fever epidemic in a four-village region of the Democratic Republic of the Congo was confirmed in September to have cases of Ebola. Many people who attended the recent funeral of a local village chief died (Formentyet al., 2003).The 2007 outbreak eventually affected 264 individuals and resulted in the deaths of 187 (WHO, 2016).
On 30 November 2007, the Uganda Ministry of Health confirmed an outbreak of Ebola in the Bundibugyo District in Western Uganda. After confirmation of samples tested by the United States National Reference Laboratories and the Centers for Disease Control, the World Health Organization confirmed the presence of a new species of genusEbolavirus, which was tentatively named Bundibugyo (CDC, 2016). The WHO reported 149 cases of this new strain and 37 of those led to deaths (WHO, 2016).
The WHO confirmed two small outbreaks in Uganda in 2012. The first outbreak affected 7 people and resulted in the death of 4 and the second affected 24, resulting in the death of 17. The Sudan variant was responsible for both outbreaks (WHO, 2016).On 17 August 2012, the Ministry of Health of the Democratic Republic of the Congo reported an outbreak of the Ebola-Bundibugyo variantin the eastern region (WHO, 2012). Other than its discovery in 2007, this was the only time that this variant has been identified as responsible for an outbreak. The WHO revealed that the virus had sickened 57 people and claimed 29 lives. The probable cause of the outbreak was tainted bush meat hunted by local villagers around the towns of Isiro and Viadana (Castillo, 2012).
In 2014, an outbreak of Ebola virus disease occurred in the Democratic Republic of the Congo (DRC). Genome-sequencing has shown that this outbreak was not related to the 2014–15 West Africa Ebola virus outbreak, but was the same EBOV species, the Zaire species (DRC, 2013). It began in August 2014 and was declared over in November of that year with a total of 66 cases and 49 deaths. This is the 7th outbreak in the DRC, three of which occurred during the period when the country was known as Zaire (DRC, (2013).
• 2014 Ebola Spread outside West Africa: As of 15 October 2014, there have been 17 cases of Ebola treated outside Africa, four of whom have died (CDC, 2014). In early October, Teresa Romero, a 44-year-old Spanish nurse, contracted Ebola after caring for a priest who had been repatriated from West Africa. This was the first transmission of the virus to occur outside Africa. On 20 October, it was announced that Teresa Romero had tested negative for the Ebola virus, suggesting that she may have recovered from Ebola infection (CDC, (2014).
On 19 September 2014, Eric Duncan flew from his native Liberia to Texas; 5 days later he began showing symptoms and visited a hospital but was sent home. His condition worsened and he returned to the hospital on 28 September, where he died on 8 October. Health officials confirmed a diagnosis of Ebola on 30 September 2014—the first case in the United States. On 12 October, the CDC confirmed that a nurse in Texas, Nina Pham, who had treated Duncan was found to be positive for the Ebola virus, the first known case of the disease to be contracted in the United States. On 15 October, a second Texas health-care worker who had treated Duncan was confirmed to have the virus. Both of these people have since recovered(Fernandez and Manny, 2014).
On 23 October2014, a doctor in New York City, who returned to the United States from Guinea after working with Doctors without Borders, tested positive for Ebola. His case is unrelated to the Texas cases. The person has recovered and was discharged from Bellevue Hospital Center on 11 November. On 24 December 2014, a laboratory in Atlanta, Georgia reported that a technician had been exposed to Ebola CDC, (2016).On 29 December 2014, Pauline Cafferkey, a British nurse who had just returned to Glasgow from Sierra Leone was diagnosed with Ebola at Glasgow’s Gartnavel General Hospital. After initial treatment in Glasgow, she was transferred by air to RAF Northolt, then to the specialist high-level isolation unit at the Royal Free Hospital in London for longer-term treatment (BBC News, 2014): .

Plate 1: Cases and deaths from April 2014 to July 2015 during the 2013–2015 outbreaks(WHO, 2015)

• 2013—2016 WEST AFRICAN OUTBREAK:In March 2014, the World Health Organization (WHO) reported a major Ebola outbreak in Guinea, a western African nation (CDC, 2014). Researchers traced the outbreak to a one-year-old child who died December 2013 (Baize et al., 2014; WHO, 2014). The disease then rapidly spread to the neighboring countries of Liberia and Sierra Leone. It is the largest Ebola outbreak ever documented, and the first recorded in the region (CDC, 2014). On 8 August 2014, the WHO declared the epidemic to be an international public health emergency. Urging the world to offer aid to the affected regions, the Director-General said, “Countries affected to date simply do not have the capacity to manage an outbreak of this size and complexity on their own. I urge the international community to provide this support on the most urgent basis possible (WHO, 2014)”.By mid-August 2014, Doctors without Borders reported the situation in Liberia’s capital Monrovia as “catastrophic” and “deteriorating daily”. They reported that fears of Ebola among staff members and patients had shut down much of the city’s health system, leaving many people without treatment for other conditions (Baize et al., 2014) In a 26 September statement, the WHO said, “The Ebola epidemic ravaging parts of West Africa is the most severe acute public health emergency seen in modern times. Never before in recorded history has a biosafety level four pathogen (WHO, 2014).
Intense contact tracing and strict isolation techniques largely prevented further spread of the disease in the countries that had imported cases; this disease is still ongoing in Guinea. As of 8 May 2016, 28,616 suspected cases and 11,310 deaths have been reported; however, the WHO has said that these numbers may be underestimated. Because they work closely with the body fluids of infected patients, healthcare workers have been especially vulnerable to catching the disease; in August, the WHO reported that ten percent of the dead have been healthcare workers (WHO, 2014).
In September 2014, it was estimated that the countries’ capacity for treating Ebola patients was insufficient by the equivalent of 2,122 beds; by December there were a sufficient number of beds to treat and isolate all reported Ebola cases, although the uneven distribution of cases was resulting in serious shortfalls in some areas. On 28 January 2015, the WHO reported that for the first time since the week ending 29 June 2014, there had been fewer than 100 new confirmed cases reported in a week in the three most-affected countries. The response to the epidemic then moved to a second phase, as the focus shifted from slowing transmission to ending the epidemic. On 8 April 2015, the WHO reported a total of only 30 confirmed cases, the lowest weekly total since the third week of May 2014 (WHO, 2015).
On 29 December 2015, 42 days after the last person tested negative for a second time, Guinea was declared free of Ebola transmission (Thomson, 2015). At that time, a 90-day period of heightened surveillance was announced by that agency. “This is the first time that all three countries – Guinea, Liberia and Sierra Leone – have stopped the original chains of transmission”, the organization stated in a news release. A new case was detected in Sierra Leone on 14 January 2016. However, the outbreak was declared no longer an emergency on 29 March 2016 (WHO, 2016).
Nigeria Outbreak: The Ebola virus was introduced into Nigeria on 20 July 2014 when an infected Liberian man, Liberian Diplomat Patrick Sawyer arrived by aeroplane into Lagos, Africa’s most populous city. He was also advised by the Liberian Health Ministry not to travel out of the country but he ignored the instruction, flew to Nigeria and died here transmitting the virus to Nigerian medical personnel who offered medical services to him.Looking to get to the bottom of Sawyer’s strange ailment on the Asky Airline flight, which Sawyer transferred on in Togo, hospital officials say, he was tested for both malaria and HIV AIDS. However, when both tests came back negative, he was then asked whether he had made contact with any person with the Ebola Virus, to which Sawyer denied. Sawyer’s sister, Princess had died of the deadly virus on Monday, July 7, 2014 at the Catholic Hospital in Monrovia. The man, who died in hospitalon Friday, July 25, 2014, 18 days later, Sawyer died in Lagosset off a chain of transmission that infected a total of 19 people, of whom 7 died. According to WHO recommendations, the end of an Ebola virus disease outbreak in a country can be declared once 42 days have passed and no new cases have been detected. The 42 days represents twice the maximum incubation period for Ebola (21 days). This 42-day period starts from the last day that any person in the country had contact with a confirmed or probable Ebola case. When the first Ebola case was confirmed in July, health officials immediately repurposed technologies and infrastructures from WHO and other partners to help find cases and track potential chains of transmission of Ebola virus disease. WHO, United States Centers for Disease Control and Prevention (CDC), Médecins Sans Frontières (MSF), UNICEF and other partners supported the Nigerian Government with expertise for outbreak investigation, risk assessment, contact tracing and clinical care. Strong public awareness campaigns, teamed with early engagement of traditional, religious and community leaders, also played a key role in successful containment of this outbreak. The surveillance system remains at a level of high alert(WHO, 2015).