Though I am a few weeks late with this post, I wanted to review the recently-released disease thriller “Contagion”.

The film features an all-star cast of Matt Damon, Laurence Fishburne, Jude Law, Gwyneth Paltrow, and Kate Winslet, among others. The films follows the global spread of a deadly disease caused by a novel virus, focusing on the CDC and WHO responses, as well as the general response of the public.

As a movie, “Contagion” was very good. Perhaps not best picture material, but it was well-written and well-acted. It was most definitely worth seeing, and I would say the same even if I weren’t a scientist.

Oftentimes, Hollywood will sacrifice good science (or any science, for that matter) in order to make a more exciting movie. Luckily, “Contagion” sacrifices very little in the way of science and still comes out with a very exciting, very accurate film. The science portrayed throughout was all possible, though perhaps a bit improbable at times.

Now, onto the science.

The virus itself is designated as MEV-1 in the movie, and though I initially thought the film would be about H5N1 (or some other influenza strain), I was pleasantly surprised when the filmmakers went a different direction.

There’s a brief image of the sequenced genome in the movie, and it appears as if the virus is very similar to Nipah virus. Well played, Hollywood. I approve greatly of your virus choice, as Nipah is an emerging infectious disease of concern in the real world.

In terms of how the virus emerged, the events were a little rushed – but it is a movie, so it’s not like they can show years of evolution. But the general concept was right on target. Deforestation by a mining company drove a bat out of its natural habitat, forcing it to take shelter at a pig farm. The bat had been carrying a piece of fruit (I like to think it was a date palm), which it dropped to the floor, where a pig ate it. The pig was then slaughtered, cooked, and served for human consumption.

Once again, well done Hollywood. Nipah virus is thought to have emerged when agricultural intensification allowed for increased bat/pig contact, mediating the emergence of a novel pathogen. The emergence event in “Contagion” was very similar, and interactions of the same nature are occurring all over the world. The use of Southeast Asia was also very accurate, as that region is seen as a mixing pot for various animal and human pathogens.

In the film, the virus readily jumped from bat to pig, reassorted, and then jumped from pig to human, where it was able infect the host and maintain efficient person-to-person transmission. Though the rapidity with which it occurred is theoretically possible, it is extremely improbable.

To illustrate this point, I’ll briefly discuss the Pathogen Pyramid, a concept developed by Wolfe et al. in 2004 to summarize disease emergence.

Woolhouse, M. E. J., Haydon, D. T., & Antia, R. (2005). Emerging pathogens: the epidemiology and evolution of species jumps. Trends in Ecology & Evolution, 20(5), 238-244. doi: 10.1016/j.tree.2005.02.009

Each level of the pyramid represents a different degree of interaction between pathogens and humans: exposure, infection, transmission, and epidemic spread. Some pathogens are able to progress from one level to another, while others are blocked by natural, biological, or man-made barriers. The pyramid provides a basic overview of how pathogens go from existing in the environment or as an animal disease to causing sustained infection in a human population.

Though humans are exposed to many potential pathogens each day, only some of these are able to cause infection. Of this group, even fewer are able to spread from person-to-person. And an even smaller percentage has the ability to maintain person-to-person spread. Though it is possible for MEV-1 to have progressed through all levels of the pyramid rapidly and effectively, it would have required a perfect storm of variables.

Assuming that MEV-1 is similar to Nipah virus, then the movie’s portrayal of the disease progression is relatively accurate. The incubation time is 2 days, which is a little short, but not outrageously unbelievable. Regarding the actual disease, the respiratory and neurological symptoms of MEV-1 are consistent with observed outbreaks of Nipah. And in the film, the disease produces a case fatality rate of 25%, lower than the CFR of Nipah virus (~40% – 75%).

The epidemiology of the film was quite accurate. From concepts like R0 and contact tracing, the work done by the CDC’s Epidemic Intelligence Service and the WHO was very representative of what would happen in real life. Granted, the EIS would almost definitely have sent multiple officers to Minnesota along with Kate Winslet’s character, but again, Hollywood needs some poetic license.

Of all the science in the movie, the most unbelievable is probably the vaccine development. First of all, finding suitable cell lines to grow virus can be extremely difficult, and finding an effective animal model can be near impossible. Additionally, those discoveries were made in the film by individuals. During the 2003 SARS outbreak, identification of the virus took weeks of worldwide collaboration, a discovery hailed as being made with “unprecedented speed.” It is unlikely that mere days of individual effort would result in identification of the virus, successful growth in cells, and implementation of an accurate animal model.

And then we come to the vaccine itself. Discovery, development, and production of the vaccine were completed in just a few months time. This is exceptionally improbable – as it is, influenza vaccine can take months to produce, and there are many diseases that scientists simply cannot produce effective vaccines against. It would take an extraordinarily fortuitous set of circumstances to permit the development of a vaccine against a novel virus so quickly.

Stepping away from the science, I thought that the response to the outbreak was extremely well done – both from a public viewpoint and a public health viewpoint. In terms of the public response, mass panic would be extremely likely. Many people would stop going to work – including those performing essential duties, such as police, fire, and emergency workers. Schools would be shut down, and looting of food and other supplies would not be surprising. This response would be similar to what is seen in the aftermath of other disasters.

What some people may find unbelievable is the public health response. The movie depicted overcrowded, ineffective hospitals. It showed a lack of effective treatments. It showed the collapse of the public health system. Hollywood sensationalism? Surprisingly not.

The U.S. public health system is woefully underprepared for a large-scale emergency event. The system lacks “surge capacity”, or the ability to ramp up response capabilities quickly during an emergency event. If a large-scale disease event were to occur, most hospitals lack enough beds, equipment, and personnel to properly manage the crisis. Hospitals would not only be overrun by the sick, but also by the “worried-well”, individuals who are healthy but believe themselves to be infected. We do not have effective vaccines, therapeutics, and treatments to counter all the diseases that exist in the world today, let alone ones that have yet to emerge.

Finally, characters like Jude Law’s would prove to be a problem – fear-mongers and snake oil salesmen who aim to profit from the crisis. Law’s character champions the effectiveness of a natural treatment, though there is no scientific basis for his claims. He lambasts the CDC and their response and urges people to refuse the vaccine. People like him can single-handedly undermine a public health response.

I am sure that there are aspects of the film that I am missing, as I saw it over a week ago. But I believe many of the salient points to be included here.

During my time at Georgetown University, my two topics of interest were public health emergency preparedness & response and emerging infectious disease ecology. “Contagion” put both of these on display, and I am thrilled with the final product.

If I learned anything while obtaining my M.S., it’s this: diseases will continue to emerge, and we will most likely be unable to catch up with nature; therefore, we need to have a public health system that is ready to respond to an emergency, and despite a decade of improvements, we are still far from that goal.

“Contagion” has the potential to do for public health what “Top Gun” did for the military – increase public awareness and increase funding. Though America is fighting through very turbulent economic times, it is important that public health not fall by the wayside.

The world hasn’t seen a widespread disease event since H1N1, so it’s understandable that preparedness may slip away from the public’s eye. But that cannot be an excuse for an unprepared system.

I aim to resume writing shortly though.

A brief update on what kept me away. I am now an ORISE fellow attached to the U.S. Food & Drug Administration’s Center for Biologics Evaluation & Research, Office of Vaccine Research & Review, Division of Viral Products, Laboratory of Retroviral Research, Molecular Retrovirology Section.

Though I am not directly involved with biodefense and biosecurity efforts in the U.S., I am keeping current and updated with issues affecting the biodefense community.

Future posts will most likely be more op-ed and shorter in length, simply as a by-product of a busy lab schedule.

Once again, sorry for my absence, and thanks for reading. Comments are always welcome. I can be reached at drglasner@gmail.com with any questions, comments, or criticisms.

The cause of the outbreak has been identified as a strain of E.coli never before isolated in humans, Shiga toxin-producing Escherichia coli O104:H4 (STEC O104:H4). The source of the outbreak has still yet to be confirmed, with officials initially suspecting cucumbers, lettuce, and tomatoes from Spain then later organic sprouts from Germany. At this point, however, it may be impossible to isolate the bacteria from a farm – the source may only be deduced via epidemiological information.

Because of next-generation sequencing techniques, the genome of the strain has already been sequenced. Early reports show close relationship with EAEC 55989 E.coli, a strain isolated in the Central African Republic and known to cause serious diarrhea. Sequencing also suggests increased pathogenicity resulting from acquisition of several virulence genes.

The strain has also shown increased resistance to antibiotics. While this may seem like yet another complicating factor, it is actually irrelevant to treatment of cases. Generally, E.coli infections are not treated with antibiotics because it is believed that the bacteria respond by producing more Shiga toxin, causing a toxin cascade and increasing damage to the body. Increased drug resistance, however, may have contributed to the survival of the bacteria on food or in the environment.

The outbreak has struck Germany hard, creating chaos in trade throughout the European Union. Luckily, it appears that the situation is stabilizing and cases of the disease are beginning to slow, though more cases are likely to appear over the next few weeks as the outbreak comes to an end.

The current STEC O104:H4 outbreak does not pose a threat to the United States, but that does not mean that the U.S. should ignore the situation in Germany. The events unfolding across the Atlantic can be viewed as a cautionary tale. A robust and comprehensive food safety program cannot be understated, for both protection against naturally occurring disease events and intentional contamination by terrorists.

Initial reports suggest that the novel strain of STEC may have emerged directly from the environment, affecting raw vegetables that were never properly washed or cooked upon arrival at their final destination. But contamination during shipping, storing, or packaging has not been ruled out. The possibility of this occurring in the United States is not out of the question, and it is important that authorities are prepared to deal with any type of food contamination.

Despite stringent food safety programs, measures, and procedures, some contamination still occurs here in America. The United States has seen several outbreaks of E.coli and Salmonella over the past decade, but even the largest (2006) pales in comparison to the outbreak in Germany. Regardless, it is important that the U.S. maintain a strong food safety program in order to safeguard Americans against deadly foodborne illnesses.

Moreover, there is the threat of deliberate contamination of the food supply. In the wake of the outbreak in Germany, the UK has discussed its vulnerabilities to such an attack. Though several experts say the U.S. is better prepared for an attack than the UK, terrorists could nonetheless attempt to taint food in America. Along the “farm to fork continuum”, there are multiple steps that terrorists could exploit, using either a biological agent (live organism or toxin) or a chemical agent to cause harm to the end consumer.

Such an attack would not only create a medical crisis, but it would also induce panic and, perhaps most importantly, have a far-reaching economic effect as well. An attack on the food supply would shatter both domestic and international confidence in food from the United States, and the financial consequences could be in the billions of dollars.

Granted, attacking American food would not be a simple task. Terrorists would need to consider where along the process they are targeting, then determine how much agent would be needed to counteract the effects of dilution. Additionally, whatever agent they select would need to survive through processing of the food, and it would need to survive cooking/heating at the end consumer’s location. Depending on the terrorists’ motives, however, simply claiming to have contaminated the food supply could result in the same dire consequences as the actual act.

Moving forward, it will be important for the United States to continue funding food safety and security program, not only to defend against terrorists, but also to ensure preparedness for naturally occurring events. The outbreak in Germany has demonstrated that novel, especially virulent pathogens have the ability to emerge without much warning from the natural environment. The same could happen here in America, and it is vital that the country is prepared.

For more information on E.coli and the current outbreak in Germany, please refer to CDC, WHO, and ProMed-Mail.

Plenty in the news about budget cuts as well, posts to come on how that’s going to to affect biodefense/public health in America.

And new disease profile on its way: Yersinia pestis, also known as Plague.

Image courtesy of the CDC

CDC Category A Bioterrorism Agent

Microbiology
Causative Agent: Botulinum neurotoxin (7 distinct types, A-G) from Clostridium botulinum bacteria. Subtypes A and B are most commonly associated with human disease, though subtypes E and F also cause human illness. Botulinum toxin is the most poisonous substance known to man.

A gram-positive, rod-shaped, obligate-anaerobic, spore-forming bacterium.

Note: botulinum toxin is the basis for Botox, the legitimate drug for genuine health problems.

Epidemiology
 The disease occurs worldwide, with the reservoir as spores in the soil. Spores are also isolated from water samples. The disease is relatively rare in the United States but more prevalent in developing countries. Different strains (i.e. different neurotoxin subtypes) are more prevalent in certain geographic areas.

Transmission
Humans can get botulism through infection with C. botulism and subsequent exposure to produced toxin or direct exposure to pre-formed toxin.

Foodborne botulism is caused by consuming food or drink contaminated with pre-formed toxin. This is associated with inadequate heating or special preparation methods. Generally, this syndrome occurs with home-canned foods and type A toxin, though it may also be caused by improperly fermented fish and type E toxin (seen most commonly in Alaska).

Wound botulism occurs when C. botulism spores germinate within necrotic tissue and release toxin. This has been increasingly related to injection drug users, though it may also occur with any improperly cleaned wound or open fracture (i.e. severe trauma).

Intestinal botulism is a result of overgrowth of C. botulism in the anaerobic portion of the large intestine, generally resulting from the consumption and subsequent germination of spores. This syndrome is often seen in infants, and for some reason, most often in California. It can be broken down into two subcategories: infant botulism and adult intestinal toxemia botulism.

Inhalational botulism occurs when aerosolized toxin is inhaled. This is not a natural route of exposure, and this is of special concern in regards to bioterrorism. The only cases of inhalational botulism to ever occur were in laboratory workers exposed via lab accident.

Despite excretion of high levels of both toxin and organism in foodborne botulism patients for weeks to months after recovery, no cases of secondary person-to-person transmission have ever been documented.

Disease Characteristics
Incubation Period: For foodborne botulism, neurological symptoms usually occur within 12-36 hours, but may take longer depending on toxin exposure. The shorter the incubation period, the more severe the disease. For wound botulism, the disease can take 4-14 days to manifest.

Foodborne botulism: symptoms follow a classic pattern of flaccid, symmetric, descending paralysis. Early symptoms include marked fatigue, weakness, and vertigo, followed by blurred vision, dry mouth, and difficulty swallowing and speaking as the toxin affects cranial nerves. Paralysis always descends through the body, and paralysis of breathing muscles may cause loss of breathing and death (without assistance from a ventilator). Gastrointestinal symptoms may also be present, including nausea, vomiting, constipation, and abdominal swelling. There is no fever or loss of consciousness associated with the disease. With proper treatment, most patients recover, and the case fatality rate (CFR) in the U.S. is 5%-10%.

Wound botulism: The disease is very similar to foodborne botulism, with the difference being the incubation period.

Infant botulism: The most common form of botulism, affecting children under 12 months of age, mostly between the ages of 6 weeks and 6 months. Infants consume spores, which germinate in the intestine, producing bacteria which produce toxin. Initial clinical symptoms are constipation and may also include loss of appetite, weakness, poor suck, altered cry, and an extreme loss of head control. Severity of disease ranges from mild illness with gradual onset that never requires hospitalization to sudden infant death. The younger the infant, the more severe the progression. The CFR of hospitalized cases is less than 1%, though it is higher without access to hospitals with a pediatric intensive care unit.

Adult intestinal toxemia botulism: Similar to infant botulism, but relatively rare. It occurs in immunocompromised adults, individuals using antimicrobials, or individuals with some anatomical or functional bowel abnormality.

Inhalational botulism: The disease has only been reported a few times, all in researchers involved in laboratory accidents. Symptoms appeared approximately 72 hours following exposure, and all recovered with treatment. The syndrome has also been produced experimentally in animal models. Little is known about the disease that results from inhalation of botulinum toxin, but it is important to research, as it is a likely route for bioterrorism.

Diagnosis
Diagnosis of botulism is made on the basis of clinical signs and patient history. The diagnosis can be confirmed by lab test, including: detection of the toxin in serum, stool, gastric aspirate, or suspected food; culture of stool or gastric aspirate (if caused by live, germinating organism); or mouse neutralization test. Several other tests for the toxin and the bacterium are available, though they are considered investigatory.

Treatment
Treatment centers around targeting the toxin, not the organism. Antitoxin exists to treat botulism, including a heptavalent antitoxin that is effective against all 7 subtypes of the toxin. For foodborne botulism, elimination of unabsorbed toxin may be effective (i.e. induced vomiting or enemas). For wound botulism, affected tissue should be removed to eliminate the bacterial source, and proper antibiotics should be administered. For all forms of botulism, supportive care is vital, including mechanical ventilation, body positioning (to make breathing easier), and parenteral nutrition (IV fluids/nutrients).

A toxoid vaccine (for toxin subtypes A-E) is available for laboratory workers and other individuals with a high risk of exposure. Limited supplies are available, and it can be acquired through the CDC as an investigational new drug.

Additionally, several novel therapies and vaccines are currently under investigation for potential use in the future.

Use as a Bioterrorism Agent
Botulinum toxin is classified as a Category A agent because it is the most poisonous known substance, it can be isolated fairly easily from soil, it can be spread via aerosol or food, and survivors would require expensive, long-term medical care.

Though never successfully used in a terrorist attack, botulinum toxin was developed as a weapon by several countries after its discovery, including the United States, Japan, and the Soviet Union. The Japanese tested the toxin on humans during World War II, and the Allies prepared thousands of doses of toxoid vaccine prior to the storming of Normandy on D-Day. Iraq also reportedly produced nearly 20,000 liters of concentrated toxin during the 1980s, including approximately 10,000 liters that was loaded into weapons. In the only known terrorist attack with botulism, the Japanese doomsday cult Aum Shinrikyo released toxin via aerosol in downtown Tokyo. Luckily, the attack was unsuccessful.

A successful attack with botulinum toxin would not only incur large medical, public health, and psychological damage, but also a large economic impact as well. Using a model to determine the total cost of medical care for 100,000 exposed individuals, Canadian researchers estimated the total cost at $5.7 billion. This impact would be magnified if the attack occurred through contamination of food or beverage sources due to loss of confidence both domestically and internationally.

Luckily, an attack with botulinum toxin would not be simple. Though it may be relatively easy to isolate spores from soil, it is very difficult to produce purified toxin. Attacks on food or water supplies would be challenging because of processing and dilution throughout the system. An aerosol attack would also reach a limited range of people, and weather conditions have the potential to seriously affect dispersion of the toxin. Finally, effective and well-documented therapies exist for treatment of botulism.

Information for this article was taken from several sources, including the CDC, CIDRAP, CBCED, the WHO’s Control of Communicable Diseases Manual, Medical Microbiology, and lecture notes from courses at Georgetown University’s Biohazardous Threat Agents & Emerging Infectious Diseases program. For more information, please consult one of those sources, or contact me, and I will do my best to assist you.

DISCLAIMER: I am not a physician, I do not possess an M.D., nor have I ever been trained in medicine. This article is meant for general public edification only, nothing more, nothing less. Do not use this to diagnose or treat patients or yourself.

Dear Colleague,

Since 1999, ProMED-mail has been a program of the International Society for Infectious Diseases (ISID; <http://www.isid.org/>). This organization, in addition to supporting and operating ProMED-mail, is committed to improving the care of patients with infectious diseases, the training of clinicians and researchers in infectious diseases and microbiology, and the control of infectious diseases around the world. It publishes the International Journal of Infectious Diseases (IJID), provides research grants and fellowships to individuals in developing countries, and sponsors the International Congress on Infectious Diseases, the International Meeting on Emerging Diseases, and the ISID-Neglected Tropical Disease Meeting.

ISID would like to welcome all ProMED’s subscribers to free, full membership in the Society. This membership will include FREE access to the IJID until May 2012, access to the ISID newsletter, and online information. Importantly, membership will make you part of a vital organization with members in nearly every country on the planet. Like ProMED’s subscribers, the Society recognizes that infectious diseases cross all national and regional boundaries and that effective long-term solutions require international scientific exchange and cooperation. The Society and its members are dedicated to developing partnerships and to finding solutions to the problem of infectious diseases across the globe.

You will soon receive an e-mail welcoming you to membership in the ISID. There is no fee required now or in the future and you will be included in all the benefits of full membership in the Society. (You will also be offered the opportunity to opt out of membership should you so choose).

This is an exciting opportunity for ProMED-mail members and for the Society to move forward together. I urge you to take advantage of this opportunity.

–
Larry Madoff, MD
Editor, ProMED-mail

This is pretty awesome. ISID is a really great organization, and I’m excited to be getting free membership just because I’m a subscriber to ProMed-Mail. Totally off-topic, but felt it warranted a post.

Image courtesy of the CDC

CDC Category A Bioterrorism Agent

Microbiology
Causative Agent: Bacillus anthracis
A gram-positive, encapsulated, spore-forming, non-motile rod.

Epidemiology
Primarily infects herbivores, and humans are an incidental host. Rarely isolated in developed countries, but the disease is prevalent in impoverished areas where vaccination of animals is not practiced. Veterinarians in contact with infected animals and people working with animal hide, wool, hair, bone, and bone products are at highest risk of exposure. The disease is endemic in agricultural regions of the world where anthrax infection in animals is common (sub-Saharan Africa, Asia, south and central America, southern and eastern Europe).

Transmission
Humans can become infected with anthrax through: contact with tissues, hair, wool, hide, or bone from animals dying of the disease or products made from them; contact with soil contaminated with anthrax; or ingestion of undercooked meat from infected animals. Anthrax can also be used as a weapon, as seen during the 2001 anthrax letter attacks. Researchers can also be exposed to the disease through accidents in the laboratory.

Transmission from person-to-person has never been observed with gastrointestinal or inhalation anthrax, and it is extremely rare with cutaneous anthrax.

Disease Characteristics
Incubation Period: 1-7 days

Cutaneous: Most common and least deadly form of the disease. Initial itching of the infected site is followed by a lesion that becomes papular then vesicular, then developing into a depressed black eschar after 2-6 days. Edema may surround the eschar. Pain is unusual with cutaneous anthrax, and when it is present, it is generally due to edema or secondary infection. Case fatality rate (CFR) is less than 1% when treated with proper antimicrobial drugs.

Gastrointestinal: Very rare and difficult to recognize form of the disease. Initial symptoms include nausea, loss of appetite, bloody diarrhea, and fever. Later symptoms include regional lymphadenopathy, edema, and septicemia. CFR is between 0%-29% when treated with antibiotics, but 25%-60% without proper treatment.

Inhalation: Initial symptoms are nonspecific, flu-like symptoms, including sore throat, mild fever and muscle aches. This is followed by the rapid onset of sepsis with fever, edema, lymphadenopathy (specifically of the mediastinal lymph nodes), non-productive cough, shortness of breath, and chest pain. Maximum CFR is estimated to be around 85% without proper treatment. The rate is considerably lower (~40%) with proper treatment.

Diagnosis
Diagnosis of anthrax is made on clinical characteristics of the disease along with positive bacterial culture from tissue or blood and supportive lab tests, including immunohistochemical stain, detection of DNA via PCR, or the presence of anti-PA (Protective Antigen, an anthrax toxin) Immunoglobulin G via ELISA.

Treatment
Post-Exposure
For individuals who have been exposed to anthrax but are not yet sick, doctors will use antibiotics (if the bacteria are sensitive), most likely Doxycycline or Ciprofloxacin, along with the anthrax vaccine (if anthrax was used as a weapon). The duration of antibiotic treatment would be 60 days.

Post-Infection
For individuals who are already sick, doctors will prescribe a long course of antibiotics (at least 60 days). For all three types of anthrax, Doxycycline or Ciprofloxacin will be used at the minimum. Gastrointestinal and inhalation anthrax require additional antibiotics, such as Rifampin, Vancomycin, or Clindamycin.

Use as a Bioterrorism Agent
Anthrax has already been used as a weapon during the 2001 anthrax letter attacks on members of Congress and of the press. B. anthracis is an attractive bioterror agent because its spores are very stable in the environment, with the ability to persist for years. Since terrorists would most likely employ an aerosol attack with spores, inhalation anthrax is the most likely clinical progression – a very serious disease. Because of the spores’ ability to persist in the environment, cleanup of contaminated sites would be extremely difficult, and this could result in denial-of-use of affected areas. The disease is also one that generates fear in the minds of citizens, since the U.S. has already been successfully attack with the agent. Depending on the size of the attack, the amount and delivery of medical countermeasures could be a problem as well.

However, the United States has done a lot to prepare for a large scale anthrax attack. From novel countermeasure development to scenario modeling, anthrax is an agent that the country is relatively well-prepared to deal with. It is also an agent used in one of the only bioterror attacks against the U.S., providing planners and policy makers with experiences to improve and build upon.

Information for this article was taken from several sources, including the CDC, CIDRAP, CBCED, the WHO’s Control of Communicable Diseases Manual, and Medical Microbiology. For more information, please consult one of those sources, or contact me, and I will do my best to assist you.

DISCLAIMER: I am not a physician, I do not possess an M.D., nor have I ever been trained in medicine. This article is meant for general public edification only, nothing more, nothing less. Do not use this to diagnose or treat patients or yourself.

I am not a doctor, and I do not possess an M.D. I have never been trained in medicine. I am a microbiologist by training, and I have academically studied all the diseases I will be covering. Just thought this was important to note.

The goal of this series will be to educate readers at a very basic level on the diseases listed by the CDC. Education helps preparedness, and individual preparedness helps the system as a whole. Writing this series also keeps me fresh and informed on some diseases of concern. It’s a win-win.

Stay tuned for more.

The discussion about smallpox destruction has been going on since shortly after the disease was eradicated from the environment. Pressure has been mounting over the past several years to destroy the last remaining stocks, located in labs in Russia and the United States. Some believe that live virus will no longer help with development of countermeasures, though those that support retention of the stocks disagree.

The debate is just as much political as it is scientific. One insider is quoted as saying “it’s more or less a division between the developed and developing world.” Though the stocks are housed in the U.S. and Russia, they are technically the property of the World Health Organization. This means that any member of WHO could, in theory, demand access to the virus to conduct research and countermeasure development. Current research poses risks as it is – adding more parties working with the virus would only increase the level of risk.

Regardless, research and development of smallpox vaccines and therapeutics is vital to preparedness. They ensure readiness in the event of a natural re-emergence or an accidental release of smallpox, and they act as an effective deterrent against terrorist use of smallpox, should such capabilities exist.

Eventually, WHO will almost certainly move to destroy the remaining stocks of smallpox. But in the meantime, the United States and Russia have a little more time to continue the valuable research currently being performed. WHO needs to ensure that it considers both the scientific and political consequences of any actions it makes, and more time to evaluate the situation is definitely not a bad thing.

According to W. Seth Carus from the National Defense University, bioterrorism is “the use, attempted use, or the credible threat to use a biological agent or a toxin by a non-state actor for the purpose of advancing a political, religious, or ideological cause.” Additionally, the CDC defines bioterrorism as “the deliberate release of viruses, bacteria, or other germs (agents) used to cause illness or death in people, animals, or plants.” Simply put, bioterrorism is the use of a biological agent as a weapon by terrorist groups.

The actual biological agents used in attacks can either be naturally-occurring or modified by humans. More primitive bioterrorists would most likely utilize a disease agent that could be isolated from nature and grown readily in a lab, whereas more advanced bioterrorists may be able to genetically alter an agent to increase its virulence, confer drug resistance, or make it more transmissible.

Agents can be disseminated in several ways, including through the air, through water, or through food. The method of dissemination depends on the biological characteristics of the agent, the capabilities of the terrorists, and the objective of the attack. No dissemination method is perfect, and all have their limitations, making it one of the biggest hurdles in any successful bioterror attack. Following dissemination, further spread of disease may occur via person-to-person transmission if the selected agent is capable of such infection.

The extent of the damage caused by a biological attack is dependent on several factors. It starts with the choice of agent and ends with the actual attack – everything from the purity of the preparation to weather conditions when dissemination occurs plays a role on the final outcome. This makes preparation for and response to an attack difficult, as there are numerous possibilities that authorities must consider.

So why would terrorists use a biological weapon? First of all, biological agents are relatively easy to obtain compared to chemical, radiological, or nuclear weapons. A big issue with biological weapons is the concept of “dual use”; that is, methods, processes, and equipment associated with legitimate biomedical laboratory research can also be used to conduct bioweapons research and development. This makes identifying offensive biological research extremely difficult.

Beyond this, biological agents have the potential to cause widespread damage. In addition to any illnesses and/or deaths that occur, a biological attack also has the ability to generate public fear and panic. Depending on the nature of the attack, the economy could struggle, the public health system could falter, and contamination could result in extensive property loss and damage. Though biological attacks may not result in mass destruction, mass disruption of normalcy in a country would almost definitely occur in the wake of a bioterror event.

Finally, biological agents disseminated by terrorists may appear identical to natural disease outbreaks. Cases may not be evident for hours or even days after initial release of the agent, providing terrorists with time to flee the affected area, notify media of the attack, or release more agent in other areas. Further, without cause to suspect an act of bioterrorism, authorities may overlook the possibility of an attack altogether. This could lead to difficulty treating the sick, spread of secondary infections, or a sudden influx of both sick and worried well patients.

The CDC has classified bioterrorism agents into three categories (A, B, C) based on how easily the agent can be spread and the severity of illness that the agent causes.

Category A agents pose the highest risk to the public and national security. These agents are characterized by high morbidity and mortality, ease of spread and transmission, potential for major public health impact, and requirement of special action for public health preparedness. The Category A agents are: Anthrax, Botulism, Plague, Smallpox, Tularemia, and Viral Hemorrhagic Fever.

Category B agents are the second highest priority because they are moderately easy to spread, result in moderate morbidity and low mortality, and require specific enhancements of the CDC’s laboratory capacity and enhanced disease monitoring. The Category B agents are: Brucellosis, Epsilon toxin of Clostridium perfringens, Food safety threats, Glanders, Melioidosis, Psittacosis, Q fever, Ricin toxin, Staphylococcal enterotoxin B, Typhus fever, Viral encephalitis, and water safety threats.

Category C agents are the third highest priority, and they include emerging pathogens that may be engineered for mass spread in the future. These agents are characterized by ease of availability, ease of production and spread, and potential for high morbidity and mortality with major health impact. Category C agents are all emerging infectious diseases, such as Nipah and Hendra viruses.

Though the threat of bioterrorism may be low compared to conventional terrorism, the consequences are disproportionately high. It is important that both policy makers and the public remain cognizant of the threat.

Over the next few weeks, I will be profiling the diseases listed in each of the three agent categories in an effort to help educate the public. More information on bioterrorism can be found here on the CDC’s website.