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- Deeksha SonnappaIX MedichampsWater Borne Diseases And Remedies

OverviewThe term "waterborne disease" is reserved largely for infections that predominantly are transmitted through contact with or consumption of infected water. Trivially, many infections may be transmitted by microbes or parasites that accidentally, possibly as a result of exceptional circumstances, have entered the water, but the fact that there might be an occasional freak infection need not mean that it is useful to categorise the resulting disease as "waterborne". Nor is it common practice to refer to diseases such as malariaas "waterborne" just becausemosquitoeshave aquatic phases in their life cycles, or because treating the water they inhabit happens to be an effective strategy in control of the mosquitoes that are thevectors.

Microorganismscausing diseases that characteristically are waterborne prominently includeprotozoaandbacteria, many of which areintestinal parasites, or invade the tissues or circulatory system through walls of the digestive tract. Various other waterborne diseases are caused byviruses. (In spite of philosophical difficulties associated with defining viruses as "organisms", it is practical and convenient to regard them as microorganisms in this connection.)Yet other important classes of water-borne diseases are caused bymetazoanparasites. Typical examples include certainNematoda, that is to say "roundworms". As an example of water-borne Nematode infections, one important waterborne nematodal disease isDracunculiasis. It is acquired by swallowing water in which certaincopepodaoccur that act as vectors for the Nematoda. Anyone swallowing a copepod that happens to be infected with Nematodelarvaein thegenusDracunculus, becomes liable to infection. The larvae causeguinea worm disease.

Diseases caused by ingestion of water, contaminated by, human or animal excerment, containing various pathogenic micro organism.Includes : Cholera Typhoid Dysenteries

CholeraAn acute diarrheal diseases, caused by Vibrio Cholerae. In the severe form, Painless watery diarrhea and copious effortless vomiting occurs, leading to hypovolemic shock and death within 24 hours.If treated early, then the diseases lasts for around 4 6 days, during which the patient loses huge amounts of liquids and electrolytes from his body.

Clinical FeaturesStool is typically, a colorless watery fluid with flecks of mucus, called rice water stools.Has a characteristic inoffensive sweetish odor, with bicarbonate rich isotonic electrolyte solution and little protein.It leads to diminution of volume, hemoconcentration, hypokalemia, base deficit acidosis and shock.Muscular cramps, Renal failure, pulmonary edema, cardiac arrhythmias, and paralytic ileus.Clinical illness begins slowly with mild diarrhea and vomiting within 1 3 days (or) abruptly with sudden massive diarrhea.

OrganismVibrios are Gram ve , rigid, curved rods.They are actively motile by means of a polar flagellum. The movement is vibratory motility, hence the name Vibrio.They are asporogenous and noncapsulated.Most important member of this genus is Vibrio Cholerae, causative agent of cholera MORPHOLOGY:It is a short, curved, cylindrical rod with rounded/pointed ends.Size: 1.5 * 0.2 - 0.4 m

Contd.Koch described these organism as fish in stream appearance as seen in thin films of mucous flakes from acute cholera cases.Strongly aerobic. In anaerobic conditions, growth is scantly.Temperature range that supports their growth is 16 - 40C, with optimum temperature being 37C.Ph that supports their growth is 6.4 9.6; optimum being 8.2.Distinguishing feature : Oxidase test : +ve

Growth on mediaNutrient Agar: Moist, translucent, round discs, about 1 2 mm in diameter, with bluish tinge in transmitted light. Has distinctive odor.MacConkey Agar: Colorless colonies at first, but later become reddish, due to prolonged incubation late fermentation of lactose occurs.Blood Agar: Initially green colored zone appears, which later becomes clear due to hemodigestion. Various special media have been employed for cultivation or orgs.

Transport Medium :Delicate organisms do not survive the time taken for transport of the specimen to the diagnostic labs / they may be overgrown by non-pathogens, Hence a special media is devised for transporting these samples , known as Transport Media. Examples : Venkataraman Ramakrishnan medium (VR) 20g crude sea salt 5g Peptone 1L Distilled water. PH is 8.6 - 8.8 Cary Blair medium : Sodium chloride + Sodium thioglycollate + Disodium Phosphate + Calcium Chloride. At PH 8.4 Autoclaved Sea water also serves as Transport media.

Biochemical TestsCarbohydrate Fermentation:

GlucoseMannitolMaltoseSucroseLactoseAcid producesAcid producesAcid producesAcid producesAcid producesNo GasNo GasNo GasNo GasLate Fermentation

Indole formation and Reduction of nitrates to Nitrites, contributes to Cholera red reaction.Other Tests :

CatalaseOxidaseMethyl RedUrease +ve +ve -ve -ve

Classification

Classification of 01

Pathogenesis : origin and development Vibrios enter orally via contaminated food and waterIn small intestine, vibrios cross mucus and reach epithelial cells by chemotaxis, motility, mucinase and with help of other proteolytic enzymes.Hemagglutinin-protease cleaves mucus & fibronectinthereby releasing the vibrios to bowel mucosa facilitating their spread to remaining parts of intestine.Adhesion to the epithelial surface is due to presence of toxin co-regulated pilus , special type of fimbria.

Mechanism:Throughout the course of infection , vibrios remain bound to the surface.Vibrios multiply on the intestinal epithelium and produce a toxin, cholera enterotoxin of 84K Daltons MW.The toxin inhibits intestinal absorption of Na and cl .Thereby causing clinical manifestations of cholera i.e., depletion of massive water and electrolytes.Vibrios also possess lipopolysaccharide O antigen - endotoxin; It has no role in pathogenesis , but helps in providing immunity induced by killed vaccines.

Laboratory Diagnosis :Stool collected at the acute stage, before administration of antibiotics, is most useful specimen in diagnosis.Isolation is easy, as vibrios are present @106 109 /ml.Samples are collected by lubricated catheters, rectal swabs absorbing around 0.1 0.2 ml.Vomits are not useful, as they have negligible amount or no amount of morgs.Collected samples ought to be preserved at 4C, as vibrios die at tropical temperatures.They are sent to labs in T.M. and then asap are transferred to Monsurs medium.

Lab Tests :No direct microscopic examination is done.Motility of vibrio is seen under dark-field/phase contrast microscope.Non-specific fluorescence is common yet complicated technique.Slide-agglutination tests may also be done, followed by chick red cell agglutination.The strains are sent to NICED : National Institute of Cholera & Enteric Diseases, Kolkata ; for further tests.

TreatmentUp to 80% of cases can be treated through oral rehydration saltsSevere cases require intravenous fluidsParenteral Vaccine : 2 doses administered 2 weeks apart 50% efficiency provides 6 months protection Killed Vaccine : Killed whole-cell + recom. B-subunit of CT Safe even during pregnancy & breastfeeding Efficiency is 75-80%,decreases to 50% - 3yrs

Prevention & Control Hygiene educationGood nutritionGood sanitationWater related issues should be addressed immediatelyPublic health infrastructure is of utmost importance to control outbreaksAvoid contacting soils that may be contaminated with fecesDo not defecate outdoors ~ rural areasWash /Sanitize our hands before eatingWhile travelling to places with poor sanitation , avoiding contaminated water

World Distribution of Cholera

TyphoidAlso Known As :

Enteric FeveBilious FeverYellow Jack

Typhoid fever is caused by Salmonella typhi.The term Enteric fever consists of both typhoid and paratyphoid fever.Typhoid was once not demarcated from normal fevers, but a detailed study of the diseases was given by Bretonneau, 1826 identified the intestinal lesions.Louis gave the name Typhoid in 1829

Salmonella:Belongs to Enterobactericieae familyGram ve rods causing intestinal infectionsFacultative anaerobes & AerobesSize :1-3m * 0.5m Motile with peritrichate flagella

Cultural Characteristics :

Grows readily on simple mediaPH range : 6-8 Temperature : 15-41CLarge colonies,2-3mm in diameter- circular, low convex translucent and smooth

Growth on media :MacConkey & Deoxycholate Citrate media : Colorless colonies due to absence of lactose fermentation .Wilson and Blair bismuth sulphite medium : Jetblack colonies with metallic sheen- H2S formsSelenite F and Tetrathionate broth are employed as Enrichment media.

Antigenic Structure:Salmonella possess the following 3 antigens , based on which they are classified and identified.3 main antigenic factors are : Flagellar antigen or H antigen Somatic antigen or O antigen Surface antigen or Vi antigenH antigen : Antigen on flagella. Heat labile protein, i.e. destroyed on heating. When mixed with antisera, agglutinate rapidly producing large, fluffy, loose clumps. Strongly Immunogenic.O antigen : Phospholipid-protein-polysaccharide complex. It is an integral part of cell wall. Identical to endotoxin. Heat resistant. On mixing with antisera, a compact, chalky, granular clumps are formed.Vi antigen : known as surface antigen or encapsulation antigen, as it encapsules or serve as a outer cover for O antigen. Heat labile, HELPS cause clinical diseases more consistently .

Modes Of Transmission :Ingestion of contaminated food or waterRarely , from person to person fecal-oral route.Food handlers/ Carriers. . . Typhoid Mary, is a classic example of carrier transmission of the diseases. Mary Mallon, a cook in New York City in early 1900s was affected by Typhoid fever; She was responsible for infecting at least 78 people and killing 5 people . She was later put in prison, to avoid passing of the infection further.

Clinical Features :ENTERIC FEVERSEPTICEMIA- with(out) local suppurative lesionsGASTROENTERITIS / FOOD POISONING Typhoid fever is a septicemia characterized by fever, bradycardia, splenomagaly, abdominal symptoms, and rose spots- which are clusters of pink mauls on the skin.Complications viz., intestinal haemorrhage or perforations develop in untreated patients or when there is a delayed treatment.

Pathogenecity:The organisms penetrate ileal mucosa reach mesenteric lymph nodes via lymphatics, multiply, invade blood stream via thoracic duct.In 7-10 days , they infect Liver, Gall-Bladder, Spleen, Kidney, Bone-Marrow.After multiplication, bacilli pass into blood causing secondary and heavy Bacteremia.Mechanism:From gall bladder, invasion occurs in intestines.Involvement of peyers patches, gut lymphoid tissues leads to inflammatory reaction.Finally leading to necrosis and formation of characteristic typhoid ulcers.

Symptoms:DiarrheaSevere headacheAbdominal painAnorexiaFeverUlcers on intestinal wallShockRose spotsintestinal hemorrhage + perforations

Blood Cultures:In adults, 5-10ml blood is collected by venepuncture inoculated into 50-100ml bile broth (0.5%)Bacteremia occurs early in blood : Week 1 90% Week 2 75% Week 3 60% Week 4 =< 25%

Biochemical Tests

IMViC Test : Name of the test Result Indole test -ve Methyl Red +ve Voges-Proskauer -ve Citrate utilization +ve Urease -ve

Sugar Fermentation :SugarsGlucoseMaltoseMannitolSorbitolSucroseLactoseAcid +ve +ve +ve +ve -ve -veGas +ve +ve +ve +ve +ve -ve

Further confirmatory tests done by Slide agglutination tests

Widal Test :The Widal test is used to make a presumptive diagnosis of enteric fever. Although the test is no longer performed in the U.S. or other developed countries, it is still in use in many developing countries where enteric fever is endemic and limited resources require the use of rapid, affordable testing alternatives.the method relies on a reaction in a test tube or on a slide between antibodiesof the infected person's blood sample and specific antigensofS. typhi, which produces clumping that is visible to the naked eye.

Control & Prevention :Simple hand hygiene and washing can reduce several cases of typhoid.Choose processed foods for safetyAll milk and dairy products should be pasteurized.Control fly populationsAny bleeding from rectum, bloody stools, sudden acute abdominal pains should be reported at once to the physician.