9 Deadliest viruses on earth

OHMYGOSSIP — How does Ebola rank among the rogue’s gallery of world’s most deadly viruses? A new ranking finds it’s among the nine most lethal pathogens, in terms of virulence and death rate.

The breakdown, compiled by the LiveScience Website, underscores the fact that vaccines and antiviral drugs have allowed us to keep infections from spreading widely, and have helped sick people recover, but that a host of infectious diseases remain a serious threat.
 
The strain behind the current epidemic, Ebola Zaire, kills 70 percent of the people it infects, making it the most lethal member of the Ebola family. But other viruses that get far less media attention are equally deadly — and some that are even deadlier.

Here’s a look, in no particular order, at the nastiest pathogens on the planet:
 
Ebola: The first Ebola outbreaks struck in the Sudan and the Democratic Republic of Congo in 1976. The five known strains vary dramatically in their deadliness. One strain, Ebola Reston, doesn’t make people sick, but — unlike the Ebola Zaire strain — is spread through the air. The current West African outbreak began in early 2014, and is the largest and most complex outbreak of the disease to date.

Marburg: Scientists identified Marburg virus in 1967 and is similar to Ebola in that both can cause hemorrhagic fever, meaning that infected people develop high fevers and bleeding throughout the body that can lead to shock, organ failure, and death. The mortality rate in the first known outbreak was 25 percent, but it was more than 80 percent in the 1998-2000 outbreak in the Democratic Republic of Congo, as well as in the 2005 outbreak in Angola, according to the World Health Organization.
 
Rabies: Rabies vaccines for pets were introduced in the 1920s, but the condition remains a serious problem in India and parts of Africa. It destroys the brain, and kills 100 percent of individual infected who are not treated.
 
HIV/AIDS: In terms of deaths, HIV/AIDs is the biggest viral killer. About 36 million people have died from HIV since the disease was first recognized in the early 1980s. Antiviral drugs have made it a manageable condition for many people with HIV in the Western world. But it continues to devastate many low- and middle-income countries, where 95 percent of new HIV infections occur. Nearly 1 in every 20 adults in Sub-Saharan Africa is HIV-positive.

Smallpox: In a huge bright spot in the war on infectious diseases, the World Health Assembly declared the world free of smallpox in 1980. Before then, humans battled smallpox for thousands of years, and the disease killed about a third of those it infected, and left survivors with deep, permanent scars.
 
Hantavirus: This disease — technically known as hantavirus pulmonary syndrome (HPS) — first gained attention in the U.S. in 1993, when a healthy, young Navajo man died within days of developing shortness of breath. A few months later, health authorities isolated hantavirus from a deer mouse. Since then, more than 600 Americans have contracted HPS, and 36 percent have died from the disease, according to the Centers for Disease Control and Prevention.
 
Influenza: While we tend to take flu for granted, up to 500,000 people worldwide die from the virus during a typical season, according to the WHO. But occasionally, a new flu strain emerges that spreads more easily and is more lethal. The most deadly flu pandemic, sometimes called the Spanish flu, began in 1918 and sickened up to 40 percent of the world’s population, killing an estimated 50 million people.
 
Dengue fever: Dengue virus first appeared in the 1950s in the Philippines and Thailand, and since then up to 40 percent of the world’s population now lives in areas where dengue is endemic. The disease — with the mosquitoes that carry it — is likely to spread farther in the years to come. It sickens 50 to 100 million people a year, according to the WHO. Although the mortality rate for dengue fever is lower than some other viruses, at 2.5 percent, the virus can cause an Ebola-like disease called dengue hemorrhagic fever, and that condition has a mortality rate of 20 percent if left untreated.

Rotavirus: Two vaccines are available against rotavirus, the leading cause of severe diarrheal illness among babies and young children. The virus can spread rapidly, through what researchers call the fecal-oral route. The WHO estimates that worldwide, 453,000 children younger than age 5 died from rotavirus infection in 2008.

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