You Give Me Fever

A QUANTUM OF SCIENCE

Emergent viral outbreaks show Ebola is not the only "hot zone" virus worth fearing

Sub-Saharan Africa has long been known as the Hot Zone, a place from which some of the world’s most deadly viruses originated. Among them are the well-known Ebola and Marburg viruses, members of the viral hemorrhagic fever (VHF) family that cause extreme fever, internal and external bleeding and rapid death among a frighteningly high percentage of those infected. Other "Old World" (i.e. African) hemorrhagic viral diseases include dengue and yellow fever. Most VHF viruses are carried by rodents – which seem largely immune – and are spread to humans by liquid contact, though some are capable of aerosol infections. (This latter category includes the Marburg virus, which was weaponized by the former Soviet Union in the 1980’s.) Less well-known cousins in this same family are the so-called New World viruses such as hantavirus, as well as the Argentine, Bolivian, and Venezuelan hemorrhagic fevers.

Late last fall an African travel agent was flown from the city of Lusaka to Johannesburg, South Africa, suffering from high fever and external bleeding. She died a few days later. Within the next several days, the paramedic who received her into the hospital, a nurse who cleaned the room following the travel agent’s death, and a nurse who attended the paramedic after he became ill, all perished from the same virus. Another nurse who treated the paramedic was given an antiviral treatment and survived. This was the beginning and end – for now – of an outbreak of the Lujo Virus, named for the two cities where it was first observed (Lusaka and Johannesburg). A member of the VHF family, it has more in common with the New World branch than it does Ebola or Marburg. Genetic analysis by researchers at Columbia University showed that the Lujo virus was a member of the arenaviridae genus (the name comes from the Latin word for sand, referring to the way viral particles of this genus appear when viewed under a microscope). Strangely, arenaviruses are almost unknown in Africa but have several species native to South America. Comparing the genetic sequence of Lujo to other VHF species from Africa showed significant differences, strongly suggesting that Lujo was not a simple mutant or even a more virulent strain caused by reassortment of viral chromosomes (such as is often the case for the influenza virus). Instead, Lujo appears to be the first high-morbidity, high-mortality VHF virus to emerge from Africa’s hot zone in the last thirty years.

In 2006 a paper was published by Dr. C.J. Peters, a member of the University of Texas Medical Branch, discussing the factors that affect the accelerating rate of emergence of new viruses and increasingly deadly outbreaks. He referenced the Emerging Microbial Threats reports issued by the Institute of Medicine in 1992 and updated in 2002, in which all the data pointed to two major factors at play in the increasing danger of deadly microbial outbreaks: multiple ecologic niches and ever-accelerating human travel and transport. In this paper he describes an arenavirus outbreak in a small village in Bolivia in 1962. The village suffered an outbreak of "black typhus" and out of 600 villager there were 107 cases, of which more than four out of ten perished. This is roughly the same morbidity and mortality rates recorded for the medieval scourge of bubonic plague, better known as the Black Death.

Since the 1960's, large sections of the Amazonian plateau have been deforested, and human activity in those regions has reached levels never before seen. The same is true of sub-Saharan Africa, where the Lujo virus emerged in 2008; had the Lujo virus not been caught before it spread thanks to current medical expertise not available in 1962, the "black typhus" outbreak may well have paled in comparison to the devastation Lujo might have wrought.

The story of ecological niches created through human activity has become hauntingly familiar, and authorities predict that the problem will only worsen as population pressures push humans deeper into the hot zones of viral reservoirs in both the Old World and the New.

For more information:

Viral hemorrhagic fever (overview)

Googleblog article on early news of the Lujo outbreak

News article on Columbia researcher’s efforts to analyze Lujo

Genetic Detection and Characterization of Lujo Virus, a New Hemorrhagic Fever–Associated Arenavirus from Southern Africa (Lipkin et al).

NOVA interview discussing Soviet weaponization of Marburg virus


© A Quantum of Science / P. Smalley
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