Reported on channel 4 (CBS) tonight, Tuesday October 17, 2006, was the story that an air monitoring station in downtown Saint Louis had yesterday detected Tuleramia, one of many potential bio-warfare agents.
The reporting was an example of responsible coverage of such issues, with appropriate perspective on the results of one air monitoring location, alone, with subsequent tests coming back negative. Tuleramia does occur naturally, and it is likely naturally occuring Tuleramia set off the alarm.
Because the report was timely, had a public health official on air (instead of just a quote), and placed the issue in perspective, I give it a B. Suggestions for improvement would be: inclusion of information that detectors in Mid west frequently show presence of naturally occurring Tularemia, the story about the detection at the National Mall in Washington last year, and a description of the steps that would be taken if it had turned out to be a real release.
From the AP:
ST. LOUIS (AP) — An air monitoring system near Busch Stadium detected levels of the biological agent tularemia, but city officials said the agent is naturally occurring and there was no indication of terrorism or wrongdoing.
Particles of tularemia, also known as rabbit fever, were detected Monday by a sensor a few blocks from the ballpark, where the Cardinals and New York Mets were playing Game 5 of the National League Championship Series Tuesday. The sensors were placed in several major cities after the Sept. 11, 2001, terrorist attacks as a way to ensure against bioterrorism.
Recall a similar event last year, when Tuleramia was detected in Air at National Mall in Washington during the anti-war protests.Tuleramia was in the news in mid 2005 when an outbreak of 96 cases was reported in the Nizhni Novgorod Region of Russia. This area was famous for a bioweapons lab during the Cold War which obviously led to speculation that the origin of the bacteria was not natural.
Mechanism of infection
Francisella tularensis is one of the most infective bacteria known; fewer than ten organisms can cause disease leading to severe illness. Humans are most often infected by tick bite or through handling an infected animal. Ingesting infected water, soil, or food can also cause infection. Tularemia can be acquired by inhalation; hunters are at a higher risk for this disease because of the potential of inhaling the bacteria during the skinning process. Tularemia is not spread directly from person to person.
Francisella tularensis is an intracellular bacterium, meaning that it is able to live as a parasite within host cells. It primarily infects macrophages, a type of white blood cell. It is thus able to evade the immune system. The course of disease involves spread of the organism to multiple organ systems, including the lungs, liver, spleen, and lymphatic system. The course of disease is similar regardless of the route of exposure. Mortality in untreated (pre-antibiotic-era) patients has been as high as 50% in the pneumoniac and typhoidal forms of the disease, which however account for <10% of cases. Overall mortality was 7% for untreated cases, and the disease responds well to antibiotics with a fatality rate of about 2%. The exact cause of death is unclear, but it is thought be a combination of multiple organ system failures.
A patient with tularemia will most often develop flu-like symptoms between 1-14 days after infection (most likely 3-5 days.) If the patient was infected through an insect or tick bite, an eschar may develop at the bite site.
The drug of choice is Streptomycin. Tularemia can also be treated with gentamicin, tetracycline or fluoroquinolone antibiotics.
Practical research into using Tularemia as a bioweapon took place at Camp Detrick in the 1950s. It was viewed as an attractive agent because:-
it is easy to aerosolize
it is highly infective; fewer than 10 bacteria are required to infect
it is non-persistent and easy to decontaminate (unlike anthrax)
it is highly incapacitating to infected persons
it has low-lethality, which is useful where enemy soldiers are in proximity to non-combattants, eg civilians
The Centers for Disease Control and Prevention regard F. tularensis as a viable bioweapons agent for use by terrorists.