Correction: Naturally occurring anthrax is found mostly in soil, where spores are deposited following the death or burial of infected animal carcasses. It, however, can be found in the hides, hair and wool salvaged from infected animals, even after processing and transport to areas far from the site of the infection. Four years ago, a major outbreak in a former Soviet state was traced to hides brought in from another country. For this reason, the recommended disposal of infected animals is incineration of the carcasses - hide, wool and all - at a consistently high temperature and making sure that the fire envelopes each entire carcass. After complete incineration, the carcasses are buried.
If carcasses are buried without complete incineration, surviving spores will lie dormant in the earth waiting for a climatological event or construction project to launch them into action. If they are less than fully consumed by fire during incineration, there is a good possibility that spores will escape into the immediate surroundings. In 1998, at a conference in South Africa, a noted microbiologist presented a finding that anthrax spores could be released during incineration of dead animals and carried on the wind to a location miles away.
There are also documented instances in which anthrax spores have been found within structures located in endemic areas. Spores, for example, were found in a national laboratory in the U.S. several years ago, when on a slow day scientists, wanting to keep busy, decided to swab surfaces in the laboratory and see what turned up. Because the facility was located in the anthrax-endemic area of the country - the tier of mid-western states from Texas north to the Canadian border, it was surmised that the spores had been in soil carried into the facility on the shoes of staff members.
" miscon[1]="The last case of inhalation anthrax in the U.S. occurred in 1978" content[1]="Correction: Prior to October 4, the most recent case of inhalation anthrax recorded in the U.S. occurred in 1976. This case was traced to yarn that had been imported from Pakistan. The media misstatement likely has its origins in statistical information released by the Centers for Disease Control that there were only 18 inhalation cases of the disease between 1900 and 1978, with the latter of the dates signaling the end year in a collation of disease reports, rather than the date of the last inhalation case.
" miscon[2]="The incubation period is 1-6 days" content[2]="Correction: The typical incubation period for inhalation and gastro-intestinal anthrax is 1-7 days; the typical period for the cutaneous form is 1-12 days. These periods have been set through analysis of patient records and through laboratory experimentation with animals and should be considered a best estimate.
In the Sverdlovsk incident (accidental release of the pathogen into the atmosphere from a bio-weapons facility) there were cases of inhalation anthrax developing as late as 43 days after initial exposure. In two experimental cases in monkeys, one fatal case appeared 58 days after deliberate infection; the other case was detected after 98 days. Experimentation with laboratory primates has shown that spores taken into the body through inhalation do not germinate immediately in the lung passages, but instead remain there as long as three or more weeks, waiting to be taken up by macrophages in which they then replicate themselves.
With particular reference to the pulmonary form of anthrax, it has been demonstrated that post-exposure prophylactic treatment with antibiotics can prolong the incubation period and the onset of clinical symptoms. Also, if at the end of the prescribed antibiotic treatment (± 60 days) there are enough non-germinated spores still remaining to overwhelm the immune system, or enough stray spores that have managed to evade the immune system, disease can develop.
" miscon[3]="A biosafety level 3 laboratory is necessary for work with anthrax" content[3]="Correction: A BL-3 laboratory is not necessary for working with anthrax; it is recommended for certain activities. If one is dealing with concentrations of bacillus anthracis cultures, dealing with high production volumes or engaging in activities that involve potential for aerosolizing the pathogen, the BL-3 practices are recommended. If one is working with clinical specimens or culturing small volumes, a BL-2 laboratory meets CDC and NIH requirements.
" miscon[4]="There are only three forms of anthrax infection" content[4]="Correction: There are only three major forms of anthrax infection. Within these three categories are two additional types - oropharyngeal and meningeal.
Oropharyngeal anthrax occurs when spores in contaminated food attach themselves to a lesion (break) in the mucous membrane of the oral cavity between the soft palate and the upper throat. It may be that small bones or gristle scratch the membrane as the contaminated meat is being swallowed. This infected lesion swells and becomes necrotic, much the same as in cutaneous anthrax, and forms a fake membrane covering within two weeks. Symptoms are sore throat, difficulty in swallowing, respiratory distress, and oral bleeding. Recovery with antibiotics takes about three weeks. The mortality rate in reported cases treated with antibiotics is 12.5%, without antibiotic treatment 50%. Cases of oropharyngeal anthrax are reported as gastrointestinal cases, even though the oropharyngeal type is the most common.
Meningeal anthrax occurs as a consequence of primary infection through cutaneous, gastrointestinal or inhalational forms of the disease. In this type of anthrax the bacteria are carried by the bloodstream to the meninges - membranes covering the spinal cord and brain, which swell and hemorrhage. Mortality is close to 100%. Of the 42 cases that underwent autopsy in the Sverdlosk situation, a full 50% (21) had meningeal involvement. In the October 2001 Florida death there was meningeal infection, and while the case is recorded as an inhalational case, at least one anthrax expert has pointed out the possibility that the respiratory findings from the autopsy may have been produced by general collapse of the organs in the terminal phase of a meningeal type of the disease, not the other way around.
" miscon[5]="Ciprofloaxcin is the drug of choice in the current anthrax situation" content[5]="Correction: According to a health advisory issued by the Centers for Disease Control on 23 October 2001, ciprofloaxcin is one of several antibiotics equally efficacious.
Researchers have isolated the bacteria from 11 human specimens and have found that in addition to ciprofloaxcin the organisms thus far isolated are equally susceptible to:
ChloramphenicolThe susceptibility to Amoxicillin and Penicillin has also been established, but to a slightly lesser degree. Further, the CDC cautions that Penicillin G, Ampicillin and similar formulations should not be used with persons exposed to high concentrations of anthrax organisms.
The susceptibility to Azithromycin is borderline susceptible; to Erythromicin it is intermediate. The isolates are RESISTANT to Ceftriaxone, which should not be used.
" miscon[6]="Anthrax is primarily a threat to humans" content[6]="Correction: Anthrax is primarily a threat to livestock. It is a zoonosis that causes exponentially fewer cases in humans than it does in grazing animals, both domestic and wild. Check out the World Animal Health Organization (Office International des Epizooties) information
" miscon[7]="The strain of anthrax that infects humans is different from the strains that infect animals" content[7]="Correction: The naturally occurring strains of anthrax that can infect humans are exactly the same strains that infect animals. And except for the deliberate introduction of the pathogen, anthrax in humans is directly derived from infected animals - through exposure to the dead animal itself or to its hide and hair. One source has said that there are about 1200 different strains worldwide.
" miscon[8]="There is one strain of anthrax named 'Ames'" content[8]="Correction: There is at least one Ames strain. The strain identified as 'Ames' in the current bioterrorist attack is a highly virulent type that (according to latest information) was isolated from an infected cow in Texas in 1980 and forwarded (in packaging bearing the name of the Veterinary Services Laboratory in Ames, Iowa) to the US Army Medical Research Institute of Infectious Diseases (USAMRIID) at Frederick, Maryland. USAMRIID, in turn, supplied it to laboratories conducting research or testing under defense contracts. If this is the only Ames strain. it has variants. If not, there are at least three Ames strains unrelated to the 1980 type. The absence of specific information has generated speculation.
SPECULATION
A. Ames/New Hampshire/Penicillin Resistant was supplied by USAMRIID in the late 1980s to the UK Porton Down Laboratory (CAMR) for testing the efficacy of a military vaccine. The nomenclature may indicate that (1) it came originally from infected New Hampshire woolen mill workers; (2) that it was resistant to penicillin; and (3) that it was in some way associated with the NVSL or some other veterinary disease research facility located in Ames. On the more troubling hand, it may indicate that the strain had been engineered to include specific characteristics of the 1980 'Ames strain', a New Hampshire strain and penicillin resistance.
B. ANR-1 was supplied by USAMRIID to a research institute in Chicago no earlier than four years ago for testing a decontaminant developed by Sandia National Laboratory. Here, the nomenclature may indicate that it was a Not Resistant or a Non-Recombinant variant of the 1980 'Ames strain'. Certainly, success of a decontaminant would not require demonstrating efficacy against antibiotic resistance. Alternatively, the strain may be one of the Ames strains held by the Naval Research Laboratory at Forest Glen, Maryland. In any case, the -1 designation suggests that more than one variant exists or is expected to emerge.
C. ASC-159 was also supplied by USAMRIID to CAMR, which later transferred a portion to a laboratory situated on a US university campus. Its nomenclature possibly suggests that it has something to do with an outbreak in the 1950s that could be stopped in South Carolina only by burning a textile mill to the ground.
SURFACING INFORMATION
ANR stands for Ames Non-Resistant (not resistant to antibiotics). ASC-159 stands for Ames sub-culture # 159.
Correction: That range was set by the American Medical Association's consensus study. The Centers for Disease Control set the range at 8,000 - 50,000; a Harvard University School of Public Health report set the range at 4,000 - 8,000. Kenneth Alibek, former official of the Soviet biological weapons program, has set the lower threshold at 25 spores. The actual lower threshold is a single spore, since that is all it takes to cause a case of human inhalation anthrax under optimal conditions. The ranges adopted by various groups reflect the actuality that the higher the spore count the more likely it is that at least one spore will survive the journey through the nasal/oral passages to the lungs and that it will be taken up by a macrophage and transported to lymph nodes, where germination begins.
To understand this expression of odds, one may draw on an analogy found in sexual reproduction. While only one sperm is needed to fertilize an ovum, if the sperm count in every ejaculation totaled exactly one, all sexually reproducing species would quickly die out. Thus, fertility specialists predict successful fertilization on the basis of sperm counts, sperm vigor and ovum viability - in the absence of other pejorative factors.
" miscon[10]="The Ames strain has occurred naturally only in the United States" content[10]="Correction: The Ames strain (or an Ames strain) has occurred naturally in South Africa. A paper presented to the Five Disease Conference in 1998 by K.L. Smith, V. DeVos, H. Bryden and M.E. Hugh-Jones, reported preliminary results from an ongoing study of environmental (soil) samples taken in the Kruger National Park. These preliminary results were that three major diversity groups were represented in samples taken between 1960 and 1997 within the park boundaries: Kruger, Southern Africa, and AMES. When the paper was published in the U.S. in 2000, the strains were re- categorized as 'Kruger A' and 'Kruger B'.
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