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Ethiopian International Journal of Multidisciplinary Research
2014; 2(2): 1-2.
1
www.eijmr.org ISSN: 2349- 5715 (Online)
ISSN: 2349- 5707 (Print)
Ebola hemorrhagic fever: An emerging highly contagious and fatal viral zoonosis
Mahendra Pal*, Pratibha Dave**, and Raj Mahendra***
*Department of Microbiology, Immunology and Public Health, College of Veterinary Medicine and Agriculture, Addis
Ababa University, P.B.No.34,Debre Zeit, Ethiopia
**Welfare Hospital and Research Center,Bharauch-392001,Gujarat,India
*** Shashwat Clinic,Bharauch-392001, Gujarat,India
*Corresponding author: Prof.Mahendra Pal
ABSTRACT: Ebola hemorrhagic fever (EHF) is the highly contagious, and most fatal emerging viral zoonosis affecting
both humans and primates. Disease in humans is transmitted by contact with infected bodily fluids and/or tissues. It is one of
the world’s most virulent diseases as the mortality is very high reaching up to 90%. The current outbreak of EHF in West
Africa is the worst in the history, and therefore, WHO has declared global health emergency. Disease manifests with a
sudden onset of an influenza-like stage characterized by general malaise, fever with chills, arthralgia, myalgia, and chest
pain. Nausea is accompanied by abdominal pain, diarrhea, and vomiting. Respiratory tract involvement is characterized by
pharyngitis with sore throat, cough, dyspnea, and hiccups. EHF most important clinical indicator is the patient's medical
history, especially travel and occupational history and the patient's exposure to wildlife. Disease can be diagnosed by ELISA,
and PCR. Currently, no approved specific therapy or potent vaccine is available for EHF. Treatment is primarily supportive
in nature .Severely ill patients require intensive supportive care. The prevention method during EVD outbreaks is not
touching the patients, their excretions, and body fluids, or possibly contaminated materials, and utensils. Future research on
the development of potent, safe, and low cost drugs, and vaccine may be highly rewarding.
Key words: Contagious, Ebola virus Humans, Fatality, Outbreak, Primates, Zoonosis
INTRODUCTION
Emerging zoonoses are important causes of high morbidity and mortality in developed and under developing counties of the
world (Pal, 2013). Among many zoonoses, Ebola hemorrhagic fever (Ebola viral disease) is a severe, contagious, and fatal
disease of humans and primates such as chimpanzees gorillas, and monkeys (Pal,2007).The first outbreaks of disease
occurred simultaneously in 1976 in Democratic Republic of Congo (DRC),and Sudan (Bennett,1995).The disease takes its
name from Ebola river in DRC where it was first recognized (WHO,2012).EHF carries high mortality from 50 to 90 %
(Pal,2005).Humans are not a natural part of Ebolavirus life cycle, and their natural reservoir (host animal) is unknown;
however, fruit bats are suspected to be reservoir of Ebola virus (Leroy et al.,2005). Once an individual is infected, the virus
spreads to others through direct contact with infected fluids and tissues. The present paper describes Ebola hemorrhagic
fever as a serious emerging highly fatal viral zoonosis which has attracted global attention due to its highly contagiousness.
ETIOLOGY
Ebola virus is a member of the family Filoviridae and the order Mononegavirales. It is caused by a viral microorganism
known as Filoviridae Ebolavirus, which is broken down into four subtypes: Ebola-Zaire, Ebola-Sudan, Ebola-Ivory Coast,
and Ebola-Reston. All but Ebola-Reston are known to cause disease in humans. Virus can be destroyed by autoclaving or
treatment with 1% formalin, 2% sodium hypochlorite, and 5 % acetic acid (CFSPH, 2009).
TRANSMISSION
Hitherto, it is not fully known how primates contract Ebola viruses in nature. The infection in humans is transmitted by
contact with contaminated blood, organs, semen or other bodily secretions. Ebola virus can be transmitted via semen up to
12 weeks after clinical recovery. Ebola can also be acquired through the handling of ill or dead chimpanzees. (Jaax, 1995).
There is evidence of a possible respiratory route of transmission of Ebola in nonhuman primates (Jaax,1995). Fomites
contaminated by blood can transmit the viruses (CFSPH,2009).
CLINICAL SPECTRUM
The incubation period of disease is 2 to 21 days. The affected person exhibits signs of fever ,headache, fatigue, malaise
,backache, chest pain, arthritis, sore throat, nausea, vomition, abdominal pain, diarrhea, conjunctivitis, coagulopathy, low
blood pressure, genital swelling, bleeding from nose, mouth, ears ,eyes ,rectum, besides rash over entire body often contains
blood ( Jeffs,2006;Pal,2007;CFSPH,2009).In primates vomiting, diarrhea, anorexia, coughing, increased salivation, bleeding
from nostrils, and emaciation are observed (CFSPH,2009).
DIAGNOSIS
Ethiopian International Journal of Multidisciplinary Research
2014; 2(2): 1-2.
2
Immunofluorescence assays are used to confirm Ebolavirus presence in cell cultures. During an outbreak, virus isolation and
electron microscopy are most often not feasible options. The most common diagnostic methods are therefore RT-PCR in
conjunction with antigen-capture ELISA which can be performed in field or mobile hospitals and laboratories (Weidmann et
al.,2004;WHO,2012). Biosecurity level P4 laboratory facility is required for isolation of virus (Pal,2007).Disease should be
differentiated from malaria ,typhoid fever ,leptospirosis, Q fever, histoplasmosis, relapsing fever,scrub typhus, plague,
visceral leishmaniasis, cholera, and shigellosis ( Jeffs,2006;WHO,2012).
EPIDEMIOLOGY
Ebola hemorrahagic fever is believed to occur after an Ebolavirus is transmitted to a human index case via contact with an
infected animal host. A large outbreak of disease occurred in Ivory Coast in 1994 in chimpanzees. Human-to-human
transmission occurs via direct contact with blood or bodily fluids from an infected person (including embalming of a
deceased victim) or by contact with contaminated medical equipment such as needles. In the past, explosive nosocomial
transmission has occurred in underequipped African hospitals due to the reuse of needles, and lack of implementation of
universal precautions. The current outbreak of disease in Western Africa is the most severe, and highly complex in the
history. It has caused great implications on public health, and economy as all flights coming from other countries were
suspended to this region of Africa. So far nearly, 170 health care workers have been affected, and more than 80 have died. In
2014, Ebola has killed over 2600 persons in African countries. WHO has warned that Ebola cases may reach 1.5 million by
January 2015.During an outbreak, health care workers, family members, and others in close contact with sick people, and
deceased patients are at higher risk of infection (WHO,2012).
TREATMENT
Presently, there is no approved Ebolavirus specific therapy for human patients. Treatment is primarily supportive in nature
and includes minimizing invasive procedures, balancing fluids and electrolytes to counter dehydration, administration of
anticoagulants early in infection to prevent or control disseminated intravascular coagulation, administration of
procoagulants late in infection to control hemorrhaging, maintaining oxygen levels, pain management, and administration
of antibiotics or antimycotics to treat secondary infections (Jeffs, 2006). Hyperimmune equine immunoglobulin raised
against Ebola has been used in Russia to treat a laboratory worker who accidentally infected herself with Ebola virus but the
patient died anyway (Jeffs, 2006).
PREVENTION AND CONTROL
Ebola viruses are highly infectious as well as contagious. As an outbreak of Ebola progresses, bodily fluids from diarrhea,
vomiting, and bleeding represent a great hazard. Due to lack of proper equipments, and hygienic practices, large-scale
epidemics occur mostly in poor, isolated areas without modern hospitals or well-educated medical staff. In such
environments, immediately cease all needle sharing or use without adequate sterilization procedures, isolate patients, and
observe strict barrier nursing procedures with the use of a medical rated disposable face mask, gloves, goggles, and a gown
at all times, strictly enforced for all medical personnel and visitors (CDC,1998).It is advised not to visit areas where
epidemic occurs .Infected animal should be euthanized, and disposed of hygienically to prevent spread of disease.The staff
members should be trained to handle the outbreal of Ebola disease. During outbreaks, strict biosecurity measures have to be
followed (CFSPH, 2009).
CONCLUSION
EVD constitutes a serious threat to both human and wildlife health. Ebola is transmitted through direct close contact with
bodily fluids of an infected subject. It is believed to spread to human populations through contact with infected primates.
Several diagnostic tests such as ELISA, PCR,virus isolation, and immunohistochemistry are available. In the absence of
specific therapy, and immunoprophylaxis, prevention predominantly include the strict isolation, proper personal protective
equipment, and sterilization/disinfection. Establishment of active animal health surveillance to detect new cases is
imperative in providing early warning to veterinary and public health authorities.
REFERENCES
Bennett, D.B. 1995. Ebola virus. British Medical Journal.310:13344-1345.
CDC, 1998. Infection Control for Viral Hemorrhagic Fevers in the African Health Care Setting. Centers for Disease Control, USA.
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Jaax, N. 1995 .Transmission of Ebola virus (Zaire strain) to uninfected control monkeys in a biocontainment laboratory. Lancet 346:1669-
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Leroy, M., Kumulungui,B., Porrut,X.,Rouguet, P. and Hassanin,A.2005.Fruit bats as reservoir of Ebola virus. Nature 438:575-576.
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