Biological disasters


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Biological disasters

  1. 1. 1. Definitions (° Biological agents ° Biological warfare/bio-terrorism )2. Causes and Methods of dissemination of biological agents3. Types (° Anthrax ° Smallpox ° Plague ° Botulism ° Tularemia)4. History: Major events across the globe5. Impact
  2. 2. Apart from the natural transnationalmovement of the pathogenic organisms,their potential use as weapons ofbiological warfare and bio-terrorism hasbecome far more important now than everbefore. Utilization of organisms causingsmallpox and anthrax by such terroristgroups can cause greater harm and panic.Biological agents are living organisms ortheir toxic products that can kill orincapacitate people, livestock, and plants.
  3. 3. Bio-terrorism can be defined as theuse of biological agents to causedeath, disability or damage mainlyto humanbeings. Thus, bio-terrorism is amethod of terrorist activity toprevail mass panicand slow mass casualties. Thethree basic groups of biologicalagents, which
  4. 4. Many break down quickly when exposed to sunlight and other environmental factors, while others, such as anthrax spores, are very long lived. Biological agents can be dispersed by spraying them into the air, by infecting animals that carry the disease to humans, and by contaminating food and water.Potentially, hundreds of human pathogens could be used as weapons; however, public health authorities have identified onlya few as having the potential to cause mass
  5. 5. There are number of causes whybiological weapons are potentially morepowerful agents to mass casualtiesleading to civil disruptions. To attractwidespread attention and to harm aselected target, these outfits can utilizepossibly any biological material, whichfulfils some of the criteria of bio-
  6. 6. • Biological agents can bedisseminated with readilyavailable technology.Common agricultural spraydevices can be adopted todisseminatebiological pathogens of the properparticle size to cause infection inhuman population over great
  7. 7. The perpetrators can use natural weatherconditions, such as wind andtemperature inversions as well as existingbuilding infrastructures (e.g. ventilationsystem) or air movement related totransportation (e.g. subway cars passingthrough tunnels) to disseminate these agentsThe expense to producing biological weaponslarge lessand thus of infect or intoxicate a is farthan that of other weapon systems.number of people.
  8. 8. • Aerosols -biological agents aredispersed into the air, forming a finemist that may drift for miles. Inhalingthe agent may cause epidemic diseases inhuman beings or animals.• Animals -some diseases are spread byinsects and animals, such as fleas, mice,flies, mosquitoes, and livestock.
  9. 9. Food and water contamination -somepathogenic organisms and toxins may persistin food and water supplies. Most microbescan be killed, and toxins deactivated, bycooking food and boiling water. Mostmicrobes are killed by boiling water for oneminute, but some require longer. Followofficial instructions.Person-to-person -spread of a few infectiousagents is also possible. Humans have beenthe source of infection for smallpox, plague,
  10. 10. There are three categories of biologicalagents potential enough to cause masscasualties. However, those in category Ahave the greatest potential for fear anddisruption and most significant publichealth impacts. The list of thesebiological agents with a very briefdescription about them is given below.
  11. 11. • The disease anthrax is caused by the gram-positive, non-motile Bacillus anthracis.Anthrax has been a scourge of cattle andother herbivores for centuries. During theindustrial revolution, the inhalation formwas first recognized as an occupationalpulmonary disease in workers in the woolindustries of Europe. Anthrax makes an idealbiological weapon. Theinhalation form of disease is highly lethal.
  12. 12. The spores can maintain virulence for decades andthey can be milled to the ideal particle size foroptimum infection of the human respiratory tract.Different clinical forms of the diseaseare observed, depending on the route of exposure.Inhalational anthrax presents with non-specificsymptoms that cannot be distinguished from manymore common diseases based on early clinicalmanifestations or routine laboratory tests.Therefore, despite aggressive medical caresometimes develop rapidly progressive disease anddye.
  13. 13. • If used as a biological weapon, smallpoxrepresents a serious threat to civilian populationbecause of its case fatality rate of 30% or moreamong unvaccinated persons and the absence ofspecific therapy. Smallpox has long beenconsidered as the most devastating of allinfectious diseases and today its potential fordevastation is far greater than at any previoustime. Smallpox virus is a member of genusOrthopoxvirus, and it is closely related to theviruses causing cowpox, vaccinia and monkey pox.
  14. 14. It is one of the largest DNA viruses known, and ithas a bricklike appearance on electron microscopy.Transmission of this virus can occur in severaldifferent ways: generally by droplets, occasionallyby aerosol, by direct contact withsecretions or lesions from a patient, and rarely byformites contacted with the infection virus from apatient.Transmission risk increases if the indexpatient is coughing or sneezing or if he or she hashemorrhagic disease.
  15. 15. Typically, the virus enters therespiratory mucosa and then travels toregional lymph nodes where it replicates.The incubation period from infection toonset of rash ranges from 7 to 17 days,averaging 12 to 14 days. Smallpox scabsremain infectious until they fall off,whereas chickenpox is no longerinfectious once the lesions are crusted.
  16. 16. • The mere mention of the word plague conjures upmany images because has already demonstrated ahistorical potential to kill millions of peopleacross the globe. It is a disease that results frominfection by non-motile, gram-negativecoccobacillus Yersinia pestis. When stained, itsbipolar appearance is often described as resemblinga safety pin. Pestis has two important propertiesthat differentiate it from B. anthracis-person-to-person transmissibility and a lack of sporeproduction.
  17. 17. Following the bite of an infected flea,plague bacilli arecarried via the lymphatic to the regionallymph nodes where they multiplyexponentially. This is only weapon besidessmallpox, which can cause devastationbeyond those persons who are initiallyinfected. With modern air travel, containingan out break of plague could be challenging.A vaccine for plague does exist; however, itis no longer being produced, and it does notdemonstrate efficacy against infection by
  18. 18. • Botulism or Botulinum toxins are deadly.A toxin is any toxic substance that can beproduced in an animal, plant, or microbe.The toxins produce serious disease in humanbeings. Many natural toxins can be producedby chemical synthesis or can be expressedartificially. Toxins are natural and non-volatile and generally do not penetrateintact skin, which happens in case ofchemical weapons.
  19. 19. There are different types of toxins and they areimmunologicallydistinct, meaning that antibodies developed against onedo not cross-react against others. Those that mostcommonly cause human disease are types A, B, and E.Humans can be intoxicated either by oral means,inhalation, or wound infection. Mass casualties can beproduced through contamination of food source or byaerosol dissemination. The incubation period of botulismcan range from as short as 24 to 36 hours to several daysfrom the time of inhalation.
  20. 20. • Tularemia is caused by Francisellatularensis, which is a gram-negative,non-motile coccobacillus. Tularemia is azoonotic disease acquired in a naturalsetting by humans through skin ormucous membrane contact with the bodyfluids or tissues of infected animals orfrom being beaten by infected deerflies,mosquitoes, or ticks. It can remainviable for weeks in the
  21. 21. environment or in animal carcasses andfor years if frozen. Unlike anthrax,which requires thousands of spores toinfect someone, tularemia can causeillness with as few as 10 to 50organisms. After an incubation period of2 to 10 days, pneumonia symptomsdevelop associated with weight loss andnonproductive cough. The drug of choicefor treatment is streptomycin with otheraminoglycosides.
  22. 22. Biological warfare has a long history of mass destructionthrough epidemic and pandemic diseases. Limitedbiological warfare is reported to have been carried out byJapan during World War-II. Recently, mycotoxins havebeen reported to be used in Afghanistan. Even before thatit has also been documented that the Red Indians inNorth America were given the smallpox infected blankets.Nevertheless, the recent Anthrax attack in 2001 throughletters caused worldwideconcerns regarding the threats of bio-terrorism.
  23. 23. Beginning in mid-September 2001, the USA experiencedunprecedented biological attacks involving the intentionaldistribution of bacillus anthracis spores through thepostal system. The full impact of this bio-terroristactivity has not been assessed, but already thetoll is large. Hundreds of people were affected. In the20th-century series of cases, the mortality rate ofoccupationally acquired Inhalational anthrax was 89%,but majority of these cases occurred before thedevelopment of critical care units and in most cases beforethe advent of antibiotics. Prior to 2001 attacks, atSverdlovsk, it had been reported that 68 of the 79patients with Inhalationalanthrax dies.
  24. 24. However, a separate reportfrom a hospital physicianrecorded 358ill with 45 dead. A recentanalysis of availableSverdlovsk data suggests thatthere may have been as many
  25. 25. Even a small-scale biological attack with aweapon grade agent on an urban center couldcause massive morbidity and mortality, rapidlyoverwhelming the local medical capabilities. Forexample, an aerosolized release of little as 100kgof anthrax spores upwind of a metro city of a sizeof Washington D C has been estimated to have thepotential to cause up to three millions of deaths.
  26. 26. .The general population should be educated and the madeaware of thethreats and risks associated with it.• Only cooked food and boiled/chlorinated/filtered watershould beconsumed• Insects and rodents control measures must be initiatedimmediately.• Clinical isolation of suspected and confirmed cases isessential.
  27. 27. 2. An early accurate diagnosis is the keyto manage casualties of biologicalwarfare. Therefore, a network ofspecialised laboratories should beestablished for a confirmatorylaboratory diagnosis.3. Existing disease surveillance systemas well as vector control measureshave be pursued more rigorously.
  28. 28. 4. Mass immunization programme in the suspectedarea has be more vigorously followed up.5. Enhancing the knowledge and skills ofclinicians plays a vital role in controlling theadverse impact of the attack. As bio-terrorismrelated infections will remain rare events, creativeongoing strategies will be required to sustainattention to potential new cases. Action Plan forBiological Disaster Management in India
  29. 29. Biological Disaster could arisefrom a source located eitherinside the country oroutside the country (warfare).Management of such a situationcould be dealt effectively only ifthere is a disaster plan wellintegrated in the system and alsothere is mechanism of post
  30. 30. This is the period betweentwo disasters in whichpre-disaster planning interms of systemdevelopment should be