Biological DisastersPresented by; Dr. Naveen Kumar,S I Ph.D., Dept of AGB.
Overview1. Definition2. Biological Agents as Causes of Mass destruction3. Sources of Biological Agents4. Methods of dissemination/delivery5. Types of Biological Agents6. History: Major Events across the Globe7. Present status and context8. Impact of Biological disasters9. Prevention of Biological disasters
Definition• Biological disasters of natural origin are largely the result of the entry of a virulent organism into a congregation of susceptible people living in a manner suited to the spread of the infection.• Anthrax - spore dispersal in the air• Small pox - aerosols• Typhus & plague - lice, fleas, rodents, etc.• Epidemic spreads locally and dies down if the contagion is localised• diseases have spread widely, even across national boundaries.
• Disasters occurred - environmental factors - conducive• Black Death occurred - increase in no. of rats• Cholera attained a pandemic form - causative agent entered urban areas which had inadequate sanitation facilities.• Similarly, post WW I, the movement of population - Spanish influenza virus.
Biological Agents as Causes of mass destruction• Highly virulent agents have the potential of infecting large numbers - infectious chains.• The potential of some infectious agents is nearly as great as that of nuclear weapons• Weapon of Mass Destruction (WMD): Nuclear, Biological and Chemical (NBC).
TRENDS FAVORING BIOLOGICAL WEAPONS• Low cost and widespread availability• More efficient in terms of coverage /Kg of payload• Advances in biotechnology have made production easy• Agents are largely natural pathogens and simulate existing diseases.• Have an unmatched destructive potential
• Technology for dispersing biological agents - sophisticated.• The lag time between infection and appearance of symptoms is longer than with chemical exposures.• Lethal biological agents can be produced easily and cheaply.
Sources of Biological Agents• Any human, animal or plant pathogen can cause an epidemic or biological weapon.• The deliberate intention/action to cause harm - biological attack.• Incident in the USA where members of a religious cult caused gastroenteritis by the use of Salmonella typhimurium (Common natural pathogen)
Methods of dissemination/delivery• Aerosols - biological agents are dispersed into the air, forming a fine mist that may drift for miles.• Animals – fleas, mice, flies, mosquitoes, and livestock.• Food and water contamination - some pathogenic organisms and toxins may persist in food and water supplies.• Person-to-person : Smallpox, Plague, and the Lassa viruses.
Types of Biological Agents• There are three categories of biological agents potential enough to cause mass casualties (Center for Disease Control & Prevention).• Category A, B & C• Those in category A have the greatest potential for fear and disruption and most significant public health impacts.
CATEGORY A• Easily disseminated or transmitted person-to-person• High mortality• Require special action for public health preparedness• Viruses: Variola major (smallpox), Filo viruses (Ebola, Marburg), Arenaviruses (Lassa, Junin)• Bacteria: Bacillus anthracis (anthrax), Yersinia pestis (plague), Francisella tularensis (tularemia)• Toxins: Clostridium botulinum toxin (botulism)
Source: Medical Management of Biological Casualties handbook, Sixth edition, April 2005;USAMRIID, Fort Detrick Frederick, Maryland
• Certain characteristics need to be present for an organism - potential biological agent for warfare or terrorist attack.• Anthrax, smallpox, plague, tularemia, brucellosis and botulinism toxin - leaders in the field.• Use of agents that target livestock and crops could be as devastating as human pathogens - probable economic impact on the community.
History: Major Events across the Globe• Biological warfare has a long history of mass destruction - epidemic and pandemic diseases.• Limited biological warfare is reported to have been carried out by Japan during World War-II• Mycotoxins have been reported to be used in Afghanisthan• the Red Indians in North America were given the smallpox infected blankets• 2001, the USA experienced biological attacks involving the intentional distribution of bacillus anthracis spores through the postal system.
Documented Intentional Use of Biologicals• Japan used plague bacilli in China during 1932-1945 causing 260,000 deaths• Dispersal of anthrax spores due to accident in production unit in USSR (Sverdlovsk) caused 68 deaths in 1979• In 1984, Osho followers used Salmonella typhimurium in salad in a restaurant in Oregaon, USA leading to 751 cases• Shigella dysenteriae Type 2 employed in Texas, USA in 1996• Anthrax spores through postal envelopes in USA in Oct- Nov 2001 leading to 22 cases and 5 deaths
Present status and context• India accorded significant priority - control & elimination of diseases - major public health burden.• Eradication of smallpox in 1975 that accounted for majority of deaths in 18th and 19th centuries.• Malaria is another major public health problem - fall in economic production with over 75 million cases annually in the early 1950s, which has now been successfully brought down to two million cases annually• plague, which had assumed epidemic proportions in the early to mid 19 th and 20th centuries, has nearly been eliminated.
• Plague outbreak in Surat (1994) with over 1,000 suspected cases and 52 deaths - widespread panic and mass exodus of people• SARS outbreak in 2003 caught the attention of the world - spread of a disease from a single hospital case to a global pandemic in less than three months.• Though India reported only three, the panic created by the media was unprecedented.• Similarly, the outbreak of avian influenza among poultry in Nandurbar and Jalgaon districts of Maharashtra and adjoining districts of Gujarat and Madhya Pradesh (2006) saw the poultry industry plummet.
• A still greater threat - possibility of avian influenza (H5N1) to become a pandemic virus that may kill millions.• The 1918 influenza pandemic killed an estimated 7 million people in India.• Slow, evolving epidemics such as HIV/AIDS - socio- economic disruption• Emerging and reemerging diseases, notably SARS, avian influenza, Nipah virus, leptospirosis, dengue, Chikungunya and Rickettsial, are also posing serious threats.
• Among the eight to ten globally recognised, most harmful Trans-boundary Animal Diseases five are existing in the country, e.g., FMD, PPR, Newcastle disease, hog cholera and bluetongue.• India has been successful recently in eradicating rinderpest• Highly Pathogenic Avian Influenza (HPAI) (bird flu) has already invaded the country on two occasions in successive years 2006 and 2007.• Through timely intervention - control the potential for a human pandemic
Impact of Biological Disasters• Bioweapons - ‘the poor man’s nuclear bomb’• Large scale operation may cost $ 2,000 per sq. km with conventional weapons,• $ 800 with nuclear weapons,• $ 600 with nerve gas weapons and• $ 1 with biological weapons.
• Dispersal experiments have been attempted using non- pathogenic Bacillus globigii• An attack on the New York subway system would kill at least 10,000 people.• WHO studies show that a 50 kg dispersal on a population of 500,000 would result in up to 95,000 fatalities.• In case of smallpox, the emergence of secondary cases at the rate of 10 times the number of primarily.• Inevitably, epidemics would break out and social chaos would ensue.
• The economic impact of BT would be a major burden• Use of Bacillus anthracis would cause losses of $26.2 billion per 100,000 persons exposed, while a less lethal pathogen, e.g., Brucella suis would cause $477.7 million.• A BT attack on agriculture can cause as much economic loss as an attack on human beings.• The spread of the Parthenium hysterophorus weed - late 1950s along with imported wheat, affected the yield of fodder crops and became a crop pest
Prevention of Biological Disastersa) Vulnerability Analysis and Risk Assessmentb) Environmental Management i. Water supply ii. Personal hygiene iii. Vector control iv. Burial/disposal of the deadc) Prevention of Post-disaster Epidemicsd) Integrated Disease Surveillance Systems
e) Pharmaceutical Interventions: Chemoprophylaxis, Immunisation and Other Preventive Measuresf) Non-pharmaceutical Interventions i. Social Distancing Measures ii. Disease Containment by Isolation and Quarantine Methodologiesg) Biosafety and Biosecurity Measures