Doctor for tropical medicine Florian Steiner (R) and ward physician Thomas Klotzkowski step out of a disinfection chamber after cleaning their protective suits at the quarantine station for patients with infectious diseases at the Charite hospital in Berlin, Germany.
Thom Lang / Corbis
May 14, 2012 -
Recent controversial experiments and a research paper that detailed how to make an airborne version of the H5N1 avian influenza virus made some people nervous. The fear is that somebody, be it a terrorist group or unethical government, could create a superbug and use it as a biological weapon. But even it the recipe for avian flu hadn't been published, there are still plenty of other viruses to choose from. To be a good biological weapon, a pathogen should be transmitted from person to person, have an incubation or contagious period long enough that the infected patient can spread it and either incapacitate or kill.
Centers for Disease Control
Smallpox Top of the list is smallpox. Historically it's had a mortality rate of 30 to 35 percent, although it was much higher, sometimes 90 percent, in populations that were never exposed to it, such as Native Americans. Smallpox is an airborne virus, which means it can be caught easily from infected people who cough or sneeze, but can also be transmitted through touch. The disease creates a fever, malaise, head and body aches and sometimes vomiting. Two to four days later, a rash develops in the mouth and throat and sores break out on the skin. This is the most contagious period. Usually the rash spreads to the entire body in 24 hours. Ironically, most people feel better at this point. The rash becomes the classic pox after about three days, in which bumps are filled with fluid. The fever rises again at this time. Over the course of another week or two the pustules scab over, and when the last one is gone, the patient is no longer contagious. Smallpox has four varieties; three are often fatal. The last naturally occurring case of the disease was in 1975, in Bangladesh. However, the virus is still in cold storage at two labs, one in the United States and the other in Russia. For now, most people in their 20s and 30s might have no immunity at all. This is especially true in developing nations whose populations are generally younger. "A new outbreak in India or South Africa, for example, would be beyond terrible," said Tara Smith, an assistant professor of epidemiology at the University of Iowa.
Michael Abbey / Visuals Unlimited / Corbis
Resistant Bacteria Diseases that have been historically treated with antibiotics are good candidates for biological weapons because many strains have become resistant to the antibiotics. Methicillin-resistant staph, or MRSA, is one of the more well-known, and is spread by physical contact. MRSA usually stays in the skin, but in some people, it infects vital organs like the heart. Some varieties have caused necrotizing fasciitis, "flesh eating disease." A drug-resistant MRSA that was immune to all of the currently known antibiotics would cause many deaths. Tuberculosis is another that has evolved drug-resistant strains. The first totally drug-resistant form was identified in 2007 in Italy and by 2010, 8.8 million people had contracted it, with 1.4 million dying. Tuberculosis is the second biggest killer behind HIV/AIDS, according to the World Health Organization. It's spread person-to-person by coughing. The bacteria multiplies in the lungs, and patients die from respiratory failure or an excess of fluid in the lungs. Artificially breeding drug-resistant bacteria is no longer that complicated, Smith said. "Antibiotic resistance genes are easy to add to almost any bug, and some plasmids already carry resistance genes for multiple classes of drugs."
Centers for Disease Control
Bubonic Plague The Black Death or bubonic plague -- officially known as Yersina pestis -- killed a third of Europe's population in the 14th century, and it still exists in some parts of the world today. It has a long history as a bioweapon: accounts of the Mongol siege of the Crimean city of Caffa in 1347 say the invaders catapulted the corpses of infected people over the walls. And it isn't just a medieval phenomenon; the last major outbreak in the United States was in 1900 in San Francisco and involved 121 people of which 113 died; cases have appeared sporadically since. The plague is transmitted by fleas, which incubate the bacterium in their gullets. The multiplying Yersina block blood from getting to the fleas' stomachs, and the starving fleas start to feed more aggressively and try to clear the blockage by regurgitating the bacteria. That transmits the disease to hosts, including humans. Symptoms appear in two to six days. The infection causes the lymph nodes to swell (the "buboes"), but sometimes the bacteria invades the bloodstream directly and causes flu-like symptoms, without the swollen lymph nodes. In either case, mortality rates can be 40 to 60 percent if untreated. Infection of the lungs is the most serious form. The patient will cough up bloody sputum and droplets that help spread the disease person-to-person, and unless treated quickly mortality can approach 100 percent. The Black Death is treatable with antibiotics such as streptomycin now, but a resistant strain could be a serious public health problem.
Centers for Disease Control
Anthrax Anthrax is spread by spores, and those spores can survive in many environments, sometimes for years. There are three ways anthrax infects: breathing the spores, eating infected meat or having the spores get into cuts on the skin. Infection through inhalation is the most likely to kill, but anthrax is still quite dangerous. As the bacteria multiply in a person, they release toxins into the blood and tissues that cause swelling and cell death. Fatality rates are high, approaching 50 percent, even with treatment by antibiotics and 90 percent without that. It's not contagious, but a bomb can be made to spread the spores and infect many people at once. The spores can even be sent in the mail, as in the 2001 anthrax attacks. In those cases, envelopes containing anthrax spores were sent to several media outlets and the offices of two senators. Five people died and another 17 were infected. "Anthrax is great from the point of view that it is stable and not usually a suspect until it's too late to treat," Smith said. Anthrax produces symptoms that look like flu and unless there is a reason to think a person is infected, a doctor might not know to test for it. For a bioweapons manufacturer, however, the lack of person-to-person transmission means it needs to be released repeatedly. Anthrax is also vulnerable to antibiotics if caught early, though drug-resistant forms of it were experimented with in the United States until 1972 and the former USSR until the projects were abandoned in 1992. In 1942 the British government tested a strain of anthrax on an island in Scotland; decontamination didn't happen until 1990.
Sion Touhig / Corbis
Agricultural Pathogens As bad as pathogens are that kill people, those that attack animals or agriculture can have effects just as devastating. Rinderpest, which was declared wiped out in 2011, killed cattle at mortality rates of 100 percent, if the population had never been exposed previously. Hoof-and-mouth disease, caused by a virus in the genus Aphthovirus, remains active. It can infect cows, pigs, sheep and goats, and causes lesions on the feet and in the mouth. The mouth lesions sometimes keep animals from eating and the foot lesions can cause lameness. Some animals die from heart inflammation. It can be spread via contact with contaminated farming equipment, vehicles, clothing or feed. It also is carried by predators. During the 2001 outbreak in the United Kingdom, anyone traveling to the United States and Europe from there was asked to step onto a disinfectant pad to decontaminate their shoes, and livestock imports from Britain to the European Union were banned. The results were millions of animals being culled and billions of dollars in containment and lost business. To create mayhem, a terrorist could spray aerosols with the virus and devastate herds. "If someone would spray every herd he/she sees from a highway going from New York to San Francisco and then driving North-South (in the middle of the country), that would do it," said Peter Palese, chair of the department of Microbiology at the Mt. Sinai School of Medicine in New York. Other diseases could also become a problem, including H5N1 avian influenza, which infects the respiratory tracts and has a high mortality rate among chickens and poultry.
The centuries-old practice of quarantine -- keeping potentially infected people locked up or at home -- is currently bumping up against Americans love of personal freedom and convenience. A TV reporter just back from Liberia decided not to follow voluntary quarantine guidelines, spreading widespread panic and possibly the killer virus itself.
In the wake of the incidents, officials at the Centers for Disease Control are vowing to give local health officials better guidelines about who should remain home. But so far, quarantines have relied on the good faith of a few individuals rather than police officers tossing people in jail.
“We need to start using quarantine orders, at least for the near term, so people are under the legal obligation to obey,” said Mark Rothstein, director of the University of Louisville’s Institute for Bioethics, Health Policy and Law. “Quarantine is a scary word and the authorities are saying these people need to be monitored. If these people felt it was OK to travel or to go out and get dinner, something is missing.”
Rothstein has studied recent quarantines, including the outbreak of Severe Acute Respiratory Syndrome (SARS) in 2004. He says that there are alternatives to quarantines, but sometimes the real deal is necessary.
“Quarantine is used because we don’t have anything else to use that is better,” he said.
In some cases, quarantines go too far. In Taiwan, for example, authorities quarantined 130,000 people when only 12 showed symptoms of SARS. Last month, the Liberian army tried to quarantine a slum area of the capital Monrovia, but residents rioted and the troops were forced to pull back.
“A quarantine is more than an inconvenience and an economic disruption,” Rothstein said. “It causes panic.”
Here in the United States, NBC's Chief Medical Correspondent Nancy Snyderman decided to leave her New Jersey home and have dinner at a nearby mall last Friday. Her cameraman contracted Ebola while on assignment in Liberia and is recovering at a hospital in Nebraska. Snyderman apologized, but her actions outraged many local residents.
And in northeast Ohio, one person has been quarantined, and six others have quarantined and are monitoring themselves for Ebola, after coming into contact or being in the vicinity of Ebola-stricken Texas nurse Amber Vinson, according to CNN. Several Texas and Ohio schools are closed as a precaution against exposing faculty and students.
Vinson traveled from Dallas to Cleveland after having reported to the CDC that she had a slight fever, and even though she was under voluntary quarantine. She now has the disease and is being treated at Emory University Hospital in Atlanta.
Doctor for tropical medicine Florian Steiner (R) and ward physician Thomas Klotzkowski step out of a disinfection chamber after cleaning their protective suits, at the quarantine station for patients with infectious diseases at the Charite hospital in Berlin, Germany.Corbis
U.S. officials have locked up some disease carriers in the past. Perhaps the most famous was “Typhoid” Mary Mallon, a New York cook who was charged with spreading the disease and was locked up from 1907 to 1910, and again from 1915 to her death in 1938. More recently, New York officials locked up 200 drug-resistant tuberculosis patients who refused treatment in the 1990s.
Federal officials can impose a mandatory quarantine on suspected carriers of cholera, diphtheria, infectious tuberculosis, plague, smallpox, yellow fever, and viral hemorrhagic fevers (such as Ebola and Marburg), according to the CDC website. A presidential executive order from last spring added new types of pandemic flus to the list.
One expert says the CDC may have to rethink the length of the current Ebola quarantine of 21 days because the incubation period may last longer in some patients. Charles Haas, professor of environmental engineering at Drexel University, recently published a study in the online journal PLOS One that found that up to 12 percent of Ebola patients may come down with the disease after three weeks has passed.
He based his findings on current and former Ebola outbreaks in Africa.
“Twelve percent is a lot,” Haas said. (The 21-day period) is not providing an absolute assurance, he said. "But any time interval is going to be a balancing test between protecting public health, the cost of enforcing it and civil liberties interests."
To keep people at home, some people under quarantine may be forced to wear electronic ankle bracelets to monitor their movements, just like criminals under house arrest.
At the same time, voluntary compliance may be higher if people were guaranteed that they wouldn’t lose their job if they have to stay home for three weeks or more. Only 10 states have laws preventing employers from firing workers who miss work because of a forced quarantine.
Despite the bad judgment by the nurse, the CDC and the journalist, one expert believes it's unlikely that the breaches of voluntary quarantines will result in new cases of Ebola.
"I get why people are scared," said Bill Hanage, associate professor of epidemiology at the Harvard School of Public Health. "But Ebola is so hard to transmit."