LEARNING OBJECTIVES• Define cholera.• State epidemiology of cholera.• Describe the causative organism.• Explain the pathophysiology of cholera.• Mention the sign & symptom, complication, risk factors, causes, diagnosis, treatment, prevention, & prognosis of cholera.• Describe the ways of controlling the spread of cholera.
CHOLERACholera is an acute diarrheal illness caused by infection of the intestine with the bacteria Vibrio cholerae.
EPIDEMIOLOGY• Cholera was prevalent in the 1800s, but due to proper treatment of sewage and drinking water, has become rare in developed countries. • Cholera is a fecal disease, meaning that it spreads when the feces of an infected person come into contact with food or water. • Incidence: 1 in 100,000 worldwide. • Over 1 million cases and nearly 10,000 fatalities.
VIBRIO CHOLERAE• Gram negative.• Type of Gammaproteobacteria• Distinguishing factors: Oxidase- positive, motile via polar flagellum, and both respiratory and fermentative metabolism.• Organism can multiply freely in water
PATHOPHYSIOLOGY OF CHOLERA V. cholerae activation of ion accumulates in increase cAMP channels stomach NaCl influx into G- protein stuck intestinal lumen Produces toxins in "on" position to drag water into lumenToxins will bind Inactivation of lead to watery to G-protein GTPase diarrheacoupled receptor
SIGNS & SYMPTOMSMost people remain asymptomatic. The symptoms of cholera include : profuse, watery stomach leg cramps Mild fever diarrhea pains Vomiting Sunken eyes Dry mucous Decreased and cheeks membranes urinary output
COMPLICATIONSsevere dehydration Shock Renal failure Death
RISK FACTORS Poor sanitary • Rare in developed countries conditions • Common in Asia, Africa, & Latin America Raw or • Contaminated seafood, even in developed countries.undercooked food • Especially shellfish. • People with low levels of stomach acidHypochlorhydria • Such as children, older adults, and some medications. • Reasons arent entirely clear Type O blood • Twice more likely
DIAGNOSISClinical diagnosis Differential diagnosis Cholera should be considered Enterotoxigenic e. Coli in all cases with severe watery diarrhea and vomiting. Bacterial food poisoning Traveling to affected areas and eating shellfish Viral gastroenteritis No distinguishing clinical manifestations for cholera.
LABORATORY DIAGNOSIS• Vibrios often detected by dark field or phase contrast microscopy of stool• Organisms are motile, appearing like “shooting stars”• Microscopy show sheets of curved Gram negative rods.• When plated on sucrose dishes, yellow colonies appear confirming cholera present
LABORATORY DIAGNOSISAdditional methods of detection includePCR and monoclonal antibody-based stool tests.
TREATMENTOral rehydration salts• Up to 80% of cases can be treated through this.Intravenous fluids (Ringer lactate)• For severe cases.Antimicrobial Therapy• can diminish duration of diarrhea, reduce volume of rehydration fluids needed, and shorten duration of V. cholerae excretion.
PREVENTION • Basic health education and hygiene • Mass chemoprophylaxis• Provision of safe water and sanitation • Comprehensive Multidisciplinary Approach: water, sanitation, education, and communication
VACCINESParenteral Vaccine : • 2 doses administered 2 weeks apart • Efficacy of approximately 50% and hardly exceeds 6 months • Not recommendedKilled WC/rBS Vaccine : • Killed whole-cell V.cholerae in combination with a recombinant B-subunit of cholera toxin • Safe in pregnancy and breastfeeding • Efficacy of approximately 50% after 3 years • Only mild side-effectsLive, attenuated CVD 103-HgR Vaccine : • Protection as early as 1 week after vaccination, with >90% • Unknown efficacy for children under 2 • No adverse side-effects
PROGNOSISThe prognosis of cholera can range dependingon the severity of the dehydration and how quickly the patient is given and responds to treatments.Death (mortality) rates in untreated cholera canbe as high as 50%-60% during large outbreaks but can be reduced to about 1% if treatment protocols are rapidly put into action.
CONTROLLING CHOLERATreatmentcenters Set up treatment centers for prompt treatment.Sanitarymeasures. food safety and animal health measuresComprehensivesurveillance (adapt to each situation) for adata comprehensive multidisciplinary approach.