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NATURAL DISASTERS-A MICROBES PARADISE- Andrea J. Linscott(Clinical Microbiology News Letter 29(8) April 2007)Natural DisasterDroughtEarthquakesHurricanesTsunamiTornadosFloodingTransmission of infectious agentsImpact phase (0-4 days)Extrication, Immediate soft tissue infectionPost impact phase (4 d 4 w)Air- borne Disease Food -borne diseaseWater -borne disease Vector- borne diseaseRecovery phase (After 4 weeks)Those with long incubation(Leptospirosis , Leishmaniasis)Most common causes of death in a disaster Diarrhea Acute respiratory infection Measles Malaria Malnutrition- WHOFactors that facilitate the spread of Microorganisms during a natural disaster Disruption of public water & sewage system Crowded living conditions Air borne transmissionLack of immunization Injury related infection due to exposure to some debrisCommunicable diseases with epidemic potential in natural disastersWaterborne Transmission Incubation periodCholera Fecal/oral, 2h-5dLepto-spirosis contaminated water 2-28dHepatitis or food 15-50dBacillary dysentery 12-96hTyphoid fever 3-14dAcute respiratoryPneumonia Person to person by 1-3dairborne respiratorydropletsDirect contactMeasles Person to person by 10-12dairborne respiratorydropletsBacterial Meningitis 2-10dVector-borneMalaria Mosquito 7-30dDengue fever Mosquito 4-7dJapanese encephalitis Mosquito 5-15dYellow fever Mosquito 3-6dDiagnosis Direct microscopic observation of V cholerae in stool Leptospira-specific IgM serologic assay Serologic assay detecting anti-HAV of anti-HEV IgM antibodies Suspect if bloody diarrhea; confirmation requires isolation of organism from stool Culture from blood, bone marrow,bowel fluids; rapid antibody tests- Salmonella typhiClinical presentation; culture respiratory secretions-Streptococcuspneumoniae, Haemophilus influenzae,Generally made by clinical observation-Measles Examination of CSF - MeningitisVector-borne Parasites on blood smear,rapid diagnostic methods Serum antibody testing with ELISA or rapid dot-blot technique-Dengue Serologic assay for JE virus IgM specific antibodies in CSF or blood Serological assay for yellow fever virus antibodiesNorthridge Earthquake 1994.An unusual outbreak of coccidiomycosis occurredThe infectious fungal spores of Coccidioides immitiswere dispersed via large dust clouds generated by landslides triggered by the earthquake.C.immitis peaked 2 weeks after the earthquakeFloodingAccounts for 40% of all natural disasters Communicable disease transmitted during the floodingWater borne diseases Vector borne diseases Typhoid fever Malaria Cholera Yellow fever Leptospirosis Water Nile fever Hepatitis A Dengue Diarrheal diseases after flooding and related displacement. Outbreak of diarrheal diseases after flooding in Bangladesh in 2004 involved > 17,000 cases of V.Cholerae and E.Coli infections. In a large study in Indonesia in 1992-1993 S. entericaparatyphi (paratyphoid fever) predominant Risk of diarrheal diseases outbreaks following natural disasteris higher in developing countries than in industrialised countries. Dominican republic-Hurricanes David and Fredrick, August 31 and Sep 5 ,1979Marked increase in Typhoid,gastroenteritis,Measles,viral-hepatitis-measured 6 months after the Hurricane Over 75,000 cases of Plasmodium falciparum malaria associated with hurricane Flora (haiti) 1966 Following hurricane Katrina (2005) several types of infections were seen V.Cholerae were confirmed among Katrina evacuees. No disease causing E.coli (CDC report)Tsunamis Infections associated with tidal wave include traumatic wound infections Aspiration pneumonia due to inhalation of soil contaminated salt waterWound infections among survivors were polymicrobic-641 organisms were identified Most prominent-Aeromonas species, E.coli ,Klebsiella pneumoniae & Psudomonas aeruginosa Some of these organisms were resistant to all licensed antibiotics Bacteriological Analysis of water samples from Tsunami hit coastal areas of Kanyakumari District, TamilNadu 151 drinking water sources collected from tsunami-affected villages and relief shelters 37 % of the water samples were contaminated.No reports of acute diarrheal diseases or typhoid during the post-tsunami period A report by the Department of Microbiology,University of MadrasP.Rajenndran et al,Indian Journal of Medical Microbiology(2006) 24 (2):114 Relationship between natural disasters and communicable diseases frequently misconstrued Fear derived from an association between large no of dead bodies and epidemicsPrimary risk factors Population displacement. Availability of safe water and sanitation facilities. Degree of crowding. Health status of population. Availability of health care services. Deaths from communicable diseases after natural disaster are less common. Outbreaks after flooding are better documented than those after earthquakes,volcanic eruptions and tsunamis Natural disasters that do not result in population displacement are rarely associated with outbreaksA pathogen can be transmitted only if it is present in the environment where the natural disaster occurred Communicable Disease Transmission Risk assessmentAn accurate communicable disease risk assessment is requiredIdentify Epidemic & endemic disease that are common in the affected area. Living conditions of the affected population. Availability of safe water and adequate sanitation facilities. Nutritional status and immunization coverage. Degree of access to healthcare.Prevention /Control Hand washing,proper handling of water/food and sewage disposal, Oral rehydration therapy(Improved Oral Rehydration salts for ORT) Avoid entering contaminated water Hepatitis vaccine Isolation , proper nutrition-If cause is Streptococcus-polyvalent vaccine (pneumonia) Rapid mass vaccination within 72h of initial case report,Vitamin A in children 6 mo to 5 yrs to prevent complications and reduce mortality (Measles)Rapid mass vaccination-meningitisMosquito control, insecticide-treated nets,bedding,clothing-malariaMosquito control,isolation of cases,mass vaccination-Dengue , Japanese encephalitis,Yellow feverRapid detection of the infectious agent is essentialDevelopment of novel diagnostic kits for rapid detection of Shigella and E.coli species-Department of Biochemistry,University of MadrasAntibiotic treatment and vaccination for Shigella species and other enteropathogens are not always successful because they are increasingly resistant to antibiotics and possess high antigenic variations.We have designed a rapid diagnostic kit and alternative therapeutic strategies Preventive Health Measures against the transmission of infectious agents related to natural disastersKey points listed by WHO Keep hands and vessels clean Avoid preparing food directly in areas surrounded by flood water. Separate raw and cooked food.Cook food thoroughly Keep food at safe temperatures Use safe water Appropriate protective clothing to be worn during rescue and clean-up operations ImmunizationTHANK YOU


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