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Dental plaque

Streptococcus mutansStreptococcus sanguis

Biolfilm:A continuously formed coatingof microorganisms & organic

matter on toGlycoprotein

Plague forms within 24hrsafter cleaning

Formation begins as positivelycharged proteins in salivaadhere to negatively chargedenamel

Dental Caries (tooth decay)

Streptococcus mutans(most common)

LactobacillusActinomyces viscosus

The chemical dissolution ofenamel & deeper parts ofteeth

The most common infectiousdisease in developingcountries because of refinedsugar in diet

Unchecked, the decay canproceed through the enamel

Into dentinPulp cavity

Eventually cause an abscess

in the bone supporting thetooth.

Formation of dental caries- Surcose =Glucose + fructose

Dextran Lactic acid

cavity

Dextran: cements bacteria totooth enamel

Lactic acid: eats tooth enamel

Periodontal disease

Cause: Gingivitis is due tothe long-term effects ofplaque deposits.Plaque is a sticky materialmade of bacteria, mucus,and food debris that

develops on the exposedparts of the teeth

Gingivitis is the mildestform of periodontal disease:only gums

Acute necrotizing ulcerativegingivitis/ trench mouth: themost severe form ofperiodontal diseaseperiodontitis

Food poisoning

Staphylococcus aureusCause: produces heat stableexotoxins

Source: egg products, meat &meat products, hands of food

preparers

S&S:- Gastroenteritis- nausea 1-6hr*- vomiting - diarrhea

* depends on the dose ofbacteria intake.

Prevention: refrigeration

growth of S. aureas

Treat: self limiting

Food poisoning

E. coli O157:H7Cause: actual infection

Source: has a reservoir incattle & other similar animals

S&S:- severe with bloody diarrhea- painful abdominal cramps- not much of fever

Complications: 3-5%: temp.anemia, profuse bleeding,kidney failure.

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Prevention:Fluoride: helps reduce thesolubility of teeth

The amount of fluoride thatcan be added to the diet/ usedtopically is limited due tofluoride toxicity

Reduce the amount of dietarysucrose (white table sugar)

Fissure sealants

Treatment:Cavities are filled w/amalugum (silver) orcomposite

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Food poisoning

Salmonellosis results fromingestion of foods containingSalmonella (enteritidis,typhimurium, choleraesuis)

Source: found in the intestines

of birds, reptiles, mammals

S&S:- fever- diarrhea- abdominal cramps

Immunocompromised: caninvade bloodstream causinglife threatening infections.

Food poisoning

Others:- Clostridium botulinum

- cyclospora: a diarrhealillness related to Guatemalanraspberries- these berries

became contaminated in fieldsw/ this unusual parasite

- Vibrio parahemolyticus:contaminated oyster beds inGalveston Bay, Texas.Caused an epidemic ofdiarrheal illness in personseating raw oysters.

- Calicivirus/ Norwalk Virus:rarely dianosised because thelab test is not widely available.S&S: causes an acute GIillness: usually w/ morevomiting than diarrhea thatresolves within 2days.

Transmit: person to person.Infected kitchen workers cancontaminate a salad/sandwich as they prepare it, ifthey have the virus on theirhands.

Bacillary Dysentery:Shigellosis

Several serotypes ofShigella: S. dysenteriae, S.flexneri, S. boydii & S.sonnei

Trans: contaminated food,fingers, flies, feces, formites

S&S:- fever- irritability- drowsiness- nausea- weight loss- vomiting- diarrhea- abdominal pain

Dysentery is rarely fatal inadults

Treatment: self limitingFlouroquinolonesFluid replacement

Cholera

Virbio cholerae (Gram -,comma shaped)

An acute, diarrheal illnessresulting from infection of theintestine

Common today in India &Africa

Enterotoxin binds to smintestine epithelia makingmembranes highly permeableto water- loss of fluids

Cl ions- inhibition of Na absorption

Trans: contaminated drinkingwater/ food (shellfish, fruit,vegetables).

S&S:- *watery diarrhea (ricewater stools)*- vomiting- leg cramps- Rapid loss of body fluidsleads to dehydration & shock- skin becomes wrinkled, eyessink inward, blood thickens,

circulation w/o treatment, death canoccur in hours

treatment:- fluid & electrolytereplacement- with prompt rehydration,fewer than 1% will die fromCholera- Antibiotics shorten thecourse, but most important is

still rehydration.

Gastric Ulcers

Helicobacter pylori (helixshaped)

- 1st

cultured in 1982 fromgastric biopsy tissues

-survives the acidity of thestomach by generatingammonia which neutralizesgastric acidity around thebacterial cells.

- colonizes & multiples in thegastric mucosa directly abovethe epithelial cell layer of thestomach: this will lead todestruction of the epitheliaresulting in an ulceration

S&S:- 95% of patients w/ duodenalulcers- 70% of patients w/ gastriculcers- burning & pain esp wheneating spicy/ sour foods

Treatment: tetracycline.Amoxicillin

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Prevention:- boil water/ treat it w/ chlorine- thoroughly cook food- avoid uncooked foods- vaccines not available in US

Diagnosis:

- lab tests- culturing stool sample-examining stools under themicroscope

Treatment:INTOXICATIONS: usuallynone, but attempt to alleviateS&S:- replace fluids & electrolytes- preparations of bismuthsubsalicylate can diarrhea

* These meds should beavoided if there is high fever/blood in stool because theymay make the illness worse.

INFECTIONS: might giveantibiotics in addition tosubstances to alleviate S&S

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Aflatoxin poisoning

Aspergullus flavus (fungal)

- produces aflatoxins: mostpotent carcingoens yetdiscovered.

- cause liver damage- aflatoxins are associatedcrops, particularly corn,cottonseeds, peanuts, andnuts.- all corn exported from theUS is required to be tested foraflatoxin.

Ergotism

Claviceps purpurea (fugal)

Occurs to some extent everyyear on cereals & grasses inN. Dakora.

Occurs in humans & livestock

Trans: eating contaminatedcereal crops & grasses (rye,barley, oat, quack grass,wheat, hay)

S&S:- animals: convulsive ergotisminclude hyperexcitability,belligerence, ataxia/staggering, lying down,convulsions & backwardarching of the back.- humans: loss of musclecoordination, tremors &weight loss

Thrush- OropharyngealCandidiasis (OPC)

Candida albicans (yeast)

Infection of the mouth andthroat

Trans: formites, imbalance oforal normal flora

Groups: newborns, children,immunocompromised,particularly AIDS patients.

S&S: white patches in themouth

Diag: swab infected tissue &examine it microscopically.

Treat: oral fluconazole/nystatin

Mumps

Mumps virus:paramyxovirus

Incubation: 14-25days

An acute viral disease

Trans: saliva & dropletsentering the oral cavity &respiratory tract

- after initially replicating in theupper respiratory tract

- virus travels in the blood tothe salivary glands & causesthem to swell

S&S :-parotitis is the most commonmanifestation:* myalgia, weight loss,malaise, headache, and low-grade fever* symptoms after 1wk &have usually resolve after10days

Prevention: MMR

Viral Enteritis

Rotavirus is a major cause

Trans: fecal-oral route

Major cause of infantmorbidity & mortality in

developing countries

Accounts for 1/3 of childhooddeaths in some countries

Virus replicates in theintestine damages theintestinal epithelium & causesa watery diarrhea &vomiting within 48hrs.

Treat: Fluid replacementSelf limiting

Prevention: sanitary practices

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Hepatitis A, B, C, D & E An inflammation of live, caused by viruses, an amoeba & various toxic chemical

A: RNA virus

- fecal oral, food borne

- 15-40days

- usually mild, rarely severe,self-limiting

- no carrier state

- no chronic liver disease

- Yes for vaccine

B: DNA virus

- blood and other bodilyfluids, crosses placenta

- 45-180 days, avg: 90days

-subclinical to severe; mostrecover completely

- yes for carrier state:associated w/ 80% of livercancer

- yes for chronic liver disease

- yes for vaccines

C: at least 2 unclassifiedRNA viruses: Flavivirus,Togavirus

- blood and blood product,occasionally crosses

placenta

- short 2-4 wksLong 8-12 wks

- subclinical to severe

- most resolve spontaneously

-yes for possible associationwith liver caner

-yes for chronic liver disease

- NO for vaccine

D: defective RNA; has HepB capsid.

- blood; Can only infect ifperson contracted HepBand D was able to use HapB

capsid. Super-infect/ co-infect

- can cross placenta

- 2-12 wks

- severe: high mortality rate

- Yes for carrier state

- no for vaccine: no need ifperson is vaccinated againstHep B

E: unclassified RNA virus:Calcivirus

- fecal oral

- more common in adults

than children

- 2-6 wks

- moderate but highmortality in pregnantwomen

- no carrier state

- no chronic liver disease

- no vaccine

Giardiasis

Giardia lamblia/ G.intestinalis(flagellated protoazoan)

Trans: fecal oral,contaminated food & watercontaining cysts (egg likestate) of G. lamblia

S&S:- bowel inflammation- weight loss- fat absorption resultingin FROTHY DIARRHEA- dehydration- deficiencies in fat solublevitamins- arthritis

Amoebic Dysentery

Entameoba histolytica(ameba)

- fecal- oralIngesting cysts in food/ watercontaminated w/ fecal matter

Incubation: 1 4 wks

S&S:Mild form: loose stools,stomach pain & cramping

Severe of amebiasis: stomachpain, bloody stools, fever

Diag: stool/ blood sample

Treatment: metronidazole

Cryptosporidosis

Cyptosporidium parvum

- found in soil, food, water,contaminated water withinfected human/ animal feces

Trans: contaminated food &water, fecal oral from kittens& puppies

S&S: most common: waterdiarrhea.

DehydrationWeight lossStomach cramp/ painNauseaFeverVomiting

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Dia: stool sample

Treat:- Metronidazole ( antifungalbut works against Giardiasis)- quinacrine

Prevention:

Maintain water supplies freeof human/ animal wastes

(flagyl)- Prevention: maintenance ofsanitary drinking water- Boil/filter water- Bottle water

Diag: stool sample

Treatment: self eliminatingImmunocompromised: noeffective treatment and maybe fatal. Esp, in AIDS patients