MODE OF TRANSMISSION
SITI NUR BAITI BINTI SHAIK KHAMARUDIN012013100196
1MODE OF TRANSMISSIONCholera is spread by contaminated water and food rather than direct person-to-person spread.Ingestion of food or water contaminated with feces or vomitus of cases or carrier/Consumption of raw or improperly cooked seafood.Other foods harvested from estuarine water or seawater. 2
INCUBATION PERIODThe incubation period ranged from few hours to 5 days, usually 2-3 days.3PERIOD OF COMMUNICABILITYFor the duration of the stool-positive stage, usually until 2-3 days after recovery, however, carrier state may persist for months. Appropriate antibiotics can shorten the period of communicability, but are not recommended for treatment.4HOST SUSCEPTIBILTY AND RESISTANCE1) Poor sanitationCholera is seen in communities with poor sanitation.Contaminated water plays a role.Cholera outbreaks happen after natural disasters - earthquake in Haiti in 2010.
52) Blood groupCholera occurs more often in person with blood type O. The mechanisms are not clearly understood.Those people are twice as likely to develop cholera as are people with other blood types. 6
3) Level of gastric acid Cholera bacteria cannot survive in an acidic environment normal level of gastric acid serves as first line defense. People with low stomach acid level children, older adults and people who take antacids, H-2 blockers or proton pump inhibitors.Lack of protection. 7Breastfed infants are at reduced risk of cholera.People who acquire antibodies by early adulthood.However, previous exposure does not confer immunity against future infection. 8WHO ARE RESISTANT?TREATMENTIntravenous fluidsOral rehydration during epidemicSeverely dehydrated patients may need IV fluids.AntibioticsNot necessary but may reduce amount & duration of cholera-related diarrhoea.Only to severe dehydrated patient.A single dose doxycycline ( Adoxa, Monodox) or azithromycin (Zithromax, Zmax). 9PREVENTION STRATEGIES Traveller educationconsult with a travel clinic regarding occurrence of cholera & vaccination recommendation.avoid eating raw oysters & undercooked shellfish and fish.
10VaccinationTwo types of oral vaccines:Dukoral - killed whole cells of V. cholerae O1 plus additional recombinant Cholera Toxin B subunit (CTB).Shanchol killed whole cells V. cholerae O139 without CTB.Both are given in 2 doses, 1-6 weeks apart.Only 2 years protection. 11
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REFERENCES Murray, Rosenthal, Pfaller. Medical Microbiology. 7th edition (2013). Elsevier Saunders.Mayo Clinic http://www.mayoclinic.org/diseases- conditions/cholera/basics/risk-factors/con-20031469?p=1 Lecture notes Ontario Ministry of Health and long-term care http://www.health.gov.on.ca/en/pro/programs/publichealth/oph_standards/docs/cholera_chapter.pdf#_ga=1.4170608.1700645002.1434292685 Manitoba Health: Public Healthhttp://www.gov.mb.ca/health/publichealth/cdc/protocol/cholera.pdf
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