Marburg virus outbreak in two African countries

Marburg virus outbreak in two African countries

Why in news:

• Early this year, Equatorial Guinea and Tanzania reported outbreaks of Marburg virus disease (MVD), the first­ever outbreak of the disease in these countries.

• As the countries respond to the outbreaks through contact tracing and restricting movement across affected regions, the World Health Organization (WHO) estimated the risk of spread of the disease as “very high” across both countries.

About the Virus:

• Marburg virus disease (MVD), formerly known as Marburg haemorrhagic fever, is a severe, often fatal illness in humans.
• The virus causes severe viral haemorrhagic fever in humans.
• The average MVD case fatality rate is around 50%.
• Case fatality rates have varied from 24% to 88% in past outbreaks depending on virus strain and case management.
• Rousettus aegyptiacus, fruit bats of the Pteropodidae family, are considered to be natural hosts of Marburg virus.
• The Marburg virus is transmitted to people from fruit bats and spreads among humans through human-to-human transmission.
• Marburg virus disease was initially detected in 1967 after simultaneous outbreaks in Marburg and Frankfurt in Germany; and in Belgrade, Serbia.
• Marburg and Ebola viruses are both members of the Filoviridae family (filovirus).
• Though caused by different viruses, the two diseases are clinically similar. Both diseases are rare and have the capacity to cause outbreaks with high fatality rates.

Transmission:

• Initially, human MVD infection results from prolonged exposure to mines or caves inhabited by Rousettus bat colonies.
• Marburg spreads through human-to-human transmission via direct contact (through broken skin or mucous membranes) with the blood, secretions, organs or other bodily fluids of infected people, and with surfaces and materials (e.g. bedding, clothing) contaminated with these fluids.
• Health-care workers have frequently been infected while treating patients with suspected or confirmed MVD.
• This has occurred through close contact with patients when infection control precautions are not strictly practiced.
• Transmission via contaminated injection equipment or through needle-stick injuries is associated with more severe disease, rapid deterioration, and, possibly, a higher fatality rate.
• Burial ceremonies that involve direct contact with the body of the deceased can also contribute in the transmission of Marburg.
• People remain infectious as long as their blood contains the virus.

Symptoms of Marburg virus disease:

• The incubation period (interval from infection to onset of symptoms) varies from 2 to 21 days.
• Illness caused by Marburg virus begins abruptly, with high fever, severe headache and severe malaise.
• Muscle aches and pains are a common feature.
• Severe watery diarrhoea, abdominal pain and cramping, nausea and vomiting can begin on the third day.
• Diarrhoea can persist for a week.
• The appearance of patients at this phase has been described as showing “ghost-like” drawn features, deep-set eyes, expressionless faces, and extreme lethargy.
• In the 1967 European outbreak, non-itchy rash was a feature noted in most patients between 2 and 7 days after onset of symptoms.

Treatment and vaccines:

• Currently there are no vaccines or antiviral treatments approved for MVD.
• However, supportive care rehydration with oral or intravenous fluids and treatment of specific symptoms, improves survival.

Syllabus: Prelims