Emerging Pathogens

What do SARS, West Nile Virus, Monkey Pox and vCJD have in common? They are all diseases caused by emerging pathogens – viruses and agents which no one knew about until their recent appearance.

In this article, you will learn about emerging pathogens – where they come from, diseases they cause, and the changes in our world that are producing them. Most important, you’ll learn some of the things you can do to reduce your risk for exposure to these emerging pathogens. It is important information for everyone – but especially important for people, in the hemophilia community, who have relied on blood-based therapies.

About Emerging Pathogens

The word pathogen means disease producer. Viruses (such as cause HIV/AIDS) and prions (such as cause vCJD) are examples of pathogens. Emerging means newly discovered or newly appearing in humans. For example, SARS was first reported in early 2003, spreading rapidly from Asia to locations throughout the world. SARS is caused by a type of virus that had not been seen before the outbreak of 2003.

There are a number of diseases that have been identified within the last 10-30 years which are caused by these newly recognized pathogens. Some examples include:

Hepatitis C
West Nile Virus
Severe Acute Respiratory Syndrome (SARS)
Monkey Pox
Avian Flu
Nipah Virus
Variant Creutzfeldt-Jakob Disease (vCJD)
Why Now?

A common question about these emerging pathogens is why we are seeing so many in this fairly short timeframe. Scientists have identified a number of reasons for the increase.

Mutations – Pathogens have the ability to change or mutate. These mutations make it more likely that they can survive efforts to eliminate them and may give them the ability to infect new groups, such as moving from animals to humans.
Population Growth – As the world population has grown, humans are increasingly moving into previously uninhabited areas. This means that they are coming into contact with animals and the pathogens they carry which have never been encountered before.
Ecological Changes – As humans move into new territory, they make changes to the environment – such as removing forests, building dams, and creating roads. These environmental changes affect animal and insect patterns, causing increased exposure to new pathogens.
Travel and Trade – With world travel and trade so common, there are many new ways for pathogens to move across borders and oceans. Many cases of SARS in the US, for example, were traced to travel in Asia or direct exposure to someone who recently traveled to Asia.
Why It’s a Problem

One of the reasons emerging pathogens are a problem is their unpredictability. No one can say when or where the next mutation or animal-to-human transmission will occur. And some of the illnesses caused by emerging pathogens do not appear immediately after a person is infected. This all means that there is no way to screen people or the blood supply for diseases we don’t yet know about. Nor is there a way to prevent people from spreading diseases before the disease is diagnosed, particularly if it is a previously unknown disease.

This situation is complex for everyone, but especially for people at risk for infection through contact with blood or blood components – such as people with hemophilia. Until recently some type of blood component, such as plasma or albumin, was used in the processing of all factor therapies.

Extraordinary efforts have been made to reduce the risks with factor therapies and, in fact, no transmissions of serious blood-borne viruses have been recorded since recombinant clotting factors were first introduced. The concern with emerging pathogens is that there is no way to screen donors or their blood/plasma for pathogens no one has yet discovered or diseases which have not been recognized.

What Can Be Done

A first important step is recognizing and understanding that risks from emerging pathogens exist. By reading this article you’ve taken a first step in that direction. At the end of this article, you’ll find links to more information about emerging pathogens and some of the diseases they cause.

The second step is to evaluate your personal risks and start looking for ways to reduce or eliminate risk of exposure to emerging pathogens. People with hemophilia are particularly at risk because of the role that blood components play in the processing of factor therapies.

Therapies using small amounts of blood components have reduced the risk from emerging pathogens. However, the newest therapies, made without any blood components, eliminate the risk of exposure associated with emerging pathogens transmitted through blood and blood components.

Finally, discuss what you have learned with your healthcare professional. You and your healthcare professional can decide together about the best way for you to manage the risk of emerging pathogens.


The Centers for Disease Control and Prevention

Medline Plus – a Service of the U.S. National Library of Medicine and the National Institutes of Health

The World Health Organization

The National Hemophilia Foundation

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