Guest Writer

Dr Faisal Siddique

It was 1976 in Republic of Zaire, when the very first outbreak of Ebola hemorrhagic fever was occurred and, later on, was reported from Sudan. It was named after the Ebola River, where the virus was first discovered. The Zaire Ebola virus has highest fatality rates as compared to Sudan Ebola virus. A large number of outbreaks in 1994, 1995, 2001, 2003, 2004, 2006 and 2014 were observed, with 90 per cent mortality rate in human beings.

In 2001, it was assumed that Ebola virus might be used as an agent of bioterrorism. The US Centers for Disease Control and Prevention (CDC) categorised this zoonotic notorious virus as an agent. It means this Ebola virus has the highest potential hazard for harming public health. According to CDC, three thousand deaths have been reported in different countries like Guinea, Liberia, Nigeria, Senegal and Sierra Leone till last September.

ETIOLOGY: The Ebola haemorrhagic fever (EHF) virus has five subtypes: Zaire ebolavirus (ZEBOV), Sudan ebolavirus (SEBOV), Côte d’Ivoire ebolavirus (CEBOV), Bundibugyoebolavirus (BEBOV) and Reston ebolavirus (REBOV). They are all present in Africa, except for Ebola-Reston which is found in the Philippines. It only affects animals.

APPROACHES FOR VIRUS: Ebola virus belongs to genus filovirus and family Filoviridae. It is enveloped, helical, filamentous, negative sense, 80-90nm in diameter and single stranded RNA virus. It is stable at 20-25c temperature, inactivated at 60°C for 20-30 minutes and can resist in desiccation. This virus is easily killed by UV light and gamma irradiation, formaldehyde, sodium hypocloride, b-propiolactoneand phenolic disinfectants.

TRANSFORMATION OF DISEASE: There are number of routes for the transmission of Ebola virus to human being including: Direct contact of skin or mucous membrane with infected tissue and body fluids; Unsafe needle injections; Nosocomial infection; Inadequate sterilization of equipment; Contact with sick or dead monkeys and chimpanzee

Drastic changes in forest ecosystems in tropical Africa could be the main factor for the direct or indirect transmission of this disease between humans and a natural reservoir of the virus. Bat is the reservoir host of Ebola virus, while it transferred from non-human primates to human primates. Its transmission may also be related to human economic activities like hunting of chimpanzee and bat, farming and gold digging. Human-to-human spread due to direct contact with infected fluids such as blood, secretions and excretions, tissues infected person and visiting and caring of sick patients.

REPLICATION AND PATHOGENESIS: Virions attached and fused to specific cell-surface receptors of host cells such as macrophages, monocytes, hepatocytes and release of the virus nuclear material into the cytosol. After fusion, Ebola virus glycoprotein (GP) was synthesized which help for overcome the immune systems of host. The negative sense RNA genome first transcribe into positive-strand mRNAs with the help of RNA polymerase, which are then translated into structural and non-structural proteins. Then, assembled the structural proteins and genomes and gather inside the cell membrane. Virions are released after budding and prepared for infection of other cells to repeat the cycle. After budding, a large number of cell signalling molecules for example TNF-α, IL-6, IL-8 for fever and inflammation.

CLINICAL PICTURE: Incubation period of this disease is from two to 21 days. There are four phases/categories about clinical findings including:

1. Influenza like Phase: Signs are observed such as high fever, headache, arthralgia, myalgia and sore throat.

2. Acute Phase (day1–6): Persistent fever not responding to anti-malaria drugs or to antibiotics, headache, intense fatigue, diarrhoea, abdominal pain and vomiting.

3. Pseudo-remission Phase (day 7–8): During this phase, the patient feels better and seeks food. The health situation presents with some improvement. Some patients may recover during this phase and survive the disease.

4. Aggravation Phase (day 9): In many cases, the health status gets worse. Symptoms such as chest pain, haemorrhagic diathesis, bloody diarrhoea, gingival bleeding, nosebleeds and bleeding at the site of injection consistent with disseminated intravascular coagulation, cardio-vascular distress and hypovolaemic shock may lead to death.

DIAGNOSIS: Definitive diagnosis of disease depends upon: History of the patients; Clinical signs and symptoms of the disease; ELISA test for antibody detection; PCR test for molecular diagnosis.

PREVENTION AND CONTROL: Preventive measures should be taken for the control of this havoc infection, which include the isolation of the infected patients, usage of proper sterilized equipments; wearing protective clothing including masks, gloves, gowns, and goggles; avoiding direct contact with the infected dead body; regular hand washing; usage of proper disinfectants for washing surfaces; adopting quarantine measures; and vaccinating the nonhuman primates.

TREATMENTS: There is no effective antiviral drug and no specific vaccine available till date. The main objective is to provide maximum care to the patient with optimal protection of the medical and nursing staff. Supportive care is usually given by the patients to get rid of this disease, which includes: Intravenous fluids administration to maintain normal levels of electrolytes; Use of breathing devices to maintain oxygen levels and drugs to control fever, use of heparin as anticoagulant medications to prevent clotting; Use of antibiotics for preventing secondary bacterial infections;     Relieving pain and keeping the environment clean as much as possible through good nursing care.