1. Diseases of the Digestive System

2. Gingivitis
Gum disease generally doesn't hurt. You may have it for years before you feel discomfort.
Telltale signs and symptoms of gingivitis:
Tender, swollen or bleeding gums, particularly when you brush your teeth
A change in your gums' color from pink to dusky red

4. Causes
Caused by plaque, a sticky, colorless film of bacteria that coats your teeth. If allowed to harden (calcify), the film turns into white- colored tartar (calculus), which becomes darker with time.
If plaque and tartar build up, they can irritate the gingiva, the part of your gum around the base of your teeth. This buildup creates pockets of bacteria between your gum and teeth and can result in gums that become inflamed and bleed easily.

5. Risk Factors
Everyone's susceptible to gum disease, and the most common contributing factor is a long-term lack of attention to proper oral hygiene. But these factors can increase your risk:
Genes. Bacteria that lead to gingivitis are more harmful to some people's gums than to others. Those who are susceptible have a hereditary predisposition to gum disease.
Medications. Some medications reduce saliva, causing a dry mouth. Without the cleansing effect of saliva, plaque and tartar can more easily build up. Hundreds of prescription and over-the-counter antidepressants and cold remedies contain ingredients that decrease your body's production of saliva. Alcohol also can decrease production of saliva.

6. Smoking. Smoking slows your gums' ability to heal themselves and replace tissue destroyed by bacteria.
Diabetes. People with uncontrolled or poorly controlled diabetes are more susceptible to gum disease. Diabetes may result in a thickening of your blood vessels, making them less able to carry nutrients to your gum tissue and remove wastes. This can leave your gums less healthy and more prone to infection.
Pregnancy. Hormone changes during pregnancy make your gums more susceptible to the damaging effects of plaque.
Decreased immunity. Illness can weaken your immune system. This makes you prone to infection, which can lead to gum disease.

7. Treatment: Gingivitis usually clears up after a professional cleaning by a dentist or hygienist, followed by proper daily oral hygiene.
Causative Agents: streptococci, actinomycetes, and anaerobic G- bacteria predominate in these infections

8. Periodontitis
Periodontitis is an advanced stage of gum (periodontal) disease that can threaten the loss of your teeth.
Some form of gum disease affects about 75 percent of adults after age 35.

9. Signs and symptoms of periodontitis may include:
Swollen or recessed gums
Unpleasant taste in your mouth
Bad breath
Pain in one of your teeth when eating hot, cold or sweet foods
Dull sound when one of your teeth is tapped
Loose teeth
Change in your bite
Drainage or pus around one or more teeth

10. If plaque and tartar extend farther, beneath your gumline you may develop periodontitis.
Your gums gradually withdraw from around your teeth. Pockets of infection (pus) can form in this dark, airless region and destroy the tissue and bone supporting your teeth.
Untreated, periodontitis will lead to your teeth loosening and falling out.

11. Treatment
If you have pockets between your gums and your teeth that are 5 millimeters or less in depth, your dentist may recommend one of the following nonsurgical treatments:
Scaling and root planing. Scaling removes tartar and bacteria from your tooth surfaces and beneath your gums. Sometimes, scaling is done with an ultrasonic device. Root planing smoothes the root surfaces, discouraging further accumulation of tartar. With good daily oral hygiene, scaling and root planing may be all the treatment you'll need.
Antibiotic therapy. Dentists can pinpoint the specific strains of bacteria that cause periodontal disease and prescribe antibiotics to deal with them.

12. If you have advanced periodontitis — the depth of the pockets between your gums and teeth is more than 5 millimeters — you may need surgery. The options:
Flap surgery. If you have a deep infection pocket, your dentist can "fold up" a section of your gum surgically, exposing the roots for more effective scaling and planing. Antibiotics may help fight the infection.
Bone grafting. If the bone surrounding your tooth root is destroyed, your dentist can secure sterilized bone segments from a bone bank to fill the space and keep your tooth in place.
Guided tissue regeneration. This technique allows bone destroyed by bacteria to regrow. Your dentist places a special piece of biocompatible fabric between existing bone and your tooth. This material prevents unwanted tissue from entering the healing area, thereby encouraging the bone to grow back.

13. Causative Agent: Porphyromonas species
Prevention
The best means of preventing gum disease is good dental hygiene, including regular brushing and flossing of your teeth and periodic professional cleaning to prevent buildup of plaque and tartar.
Causative Agent: Porphyromonas species

14. Diseases of Lower Digestive System
Two types: infection and intoxication
infection: pathogen enters GI tract and multiplies
intoxication: ingestion of pre-formed toxin
Both types of infection often cause diarrhea.
Dysentery: sever diarrhea accompanied by blood or mucus
Both types of infection are frequently accompanied by abdominal cramps, nausea, and vomiting

15. Gastroenteritis: general term for diseases causing inflammation of the stomach and intestinal mucosa.
Most common causative agents: rotavirus, some E-coli species and Shigella species.

16. Staphyloccocal Food Poisoning
Leading cause of gastroenteritis
an intoxication caused by ingesting toxin produced by S. aureus
Highly resistant to heat, drying, radiation and osmotic presures

17. Process of infection

18. Toxin quickly triggers brain’s vomiting reflexcenter; abdominal cramps and usually diarrhea ensue
Recovery is usually complete within 24 hours
Mortality rate is almost zero among healthy people

19. Shigellosis:
a severe form of diarrhea caused by group of facultative anaerobic G- rods of the genus Shigella
Most common species in the US is S. sonnei (traveler’s diarrhea)
Infection with S. dysenteriae often results in severe dysentery and prostration
Shiga toxin responsible for inhibition of protein synthesis
Bacteria not really affected by stomach acidity
Cause damage to intestinal mucosa resulting in fluid loss and inability to absorb fluid from the intestines.

20. Treatment: anitibiotic therapy and oral rehydration
Generally self-limiting. (In other words, all the fluid that is lost from the body during the disease helps to wash out the bacteria from the body.)

21. Salmonellosis: Causative agent: Salmonella enterica
Every year, approximately 40,000 cases of salmonellosis are reported in the United States.
Because many milder cases are not diagnosed or reported, the actual number of infections may be twenty or more times greater.
Children are the most likely to get salmonellosis.
Young children, the elderly, and the immunocompromised are the most likely to have severe infections.
It is estimated that approximately 1,000 persons die each year with acute salmonellosis.

22. Incubation period of 12-72 hours Lasts for 4-7 days
Invade intestinal mucosa first and multiply there
Sometimes manage to pass through intestinal mucosa and invade lymphatic and cardiovascular systems
Symptoms:
Fever
Nausea
Abdominal pain and cramps
diarrhea

23. Treatment:
Antibiotics are not usually necessary unless the infection spreads from the intestines, then it can be treated with ampicillin, gentamicin, trimethoprim/sulfamethoxazole, or ciprofloxacin.
Unfortunately, some Salmonella bacteria have become resistant to antibiotics, largely as a result of the use of antibiotics to promote the growth of feed animals

24. Transmission:
Salmonella live in the intestinal tracts of humans and other animals, including birds.
Salmonella are usually transmitted to humans by eating foods contaminated with animal feces.
Contaminated foods usually look and smell normal.
Contaminated foods are often of animal origin, such as beef, poultry, milk, or eggs, but all foods, including vegetables may become contaminated.
Many raw foods of animal origin are frequently contaminated, but fortunately, thorough cooking kills Salmonella.
Food may also become contaminated by the unwashed hands of an infected food handler, who forgot to wash his or her hands with soap after using the bathroom.

25. Salmonella may also be found in the feces of some pets, especially those with diarrhea, and people can become infected if they do not wash their hands after contact with these feces.
Reptiles are particularly likely to harbor Salmonella and people should always wash their hands immediately after handling a reptile, even if the reptile is healthy.
Adults should also be careful that children wash their hands after handling a reptile.

26. Prevention: There is no vaccine to prevent salmonellosis.
Since foods of animal origin may be contaminated with Salmonella, people should not eat raw or undercooked eggs, poultry, or meat.
Raw eggs may be unrecognized in some foods such as homemade hollandaise sauce, caesar and other salad dressings, tiramisu, homemade ice cream, homemade mayonnaise, cookie dough, and frostings.
Poultry and meat, including hamburgers, should be well-cooked, not pink in the middle.
Persons also should not consume raw or unpasteurized milk or other dairy products.
Produce should be thoroughly washed before consuming.

27. Cross-contamination of foods should be avoided.
Uncooked meats should be keep separate from produce, cooked foods, and ready-to-eat foods.
Hands, cutting boards, counters, knives, and other utensils should be washed thoroughly after handling uncooked foods.
Hand should be washed before handling any food, and between handling different food items.
People who have salmonellosis should not prepare food or pour water for others until they have been shown to no longer be carrying the Salmonella bacterium.
People should wash their hands after contact with animal feces.
Since reptiles are particularly likely to have Salmonella, everyone should immediately wash their hands after handling reptiles.
Reptiles (including turtles) are not appropriate pets for small children and should not be in the same house as an infant.

28. Cholera Causative Agent: Vibrio cholerae
Outbreaks caused by temporary lapses in sanitation practices
Cholera bacteria commonly associated with brackish (salty) waters
Under unfavorable conditions, the bacterial cell shrinks drastically into a nonculturable, spherical, dormant state
sporelike state without formation of a true spore coat

29. Both sporelike and vegetative forms are infectious.
Grows in small intestine and produce an enterotoxin that results in the secretion of chlorides, bicarbonates, and water.
Excess water and mineral electrolytes are excreted taking on the appearance of “rice water stools”
Sudden loss of fluids and electrolytes causes shock, collapse, and often death (3-5 gallons/day are lost.)

30. Vaccine available but only produces short term immunity
Loss of fluid causes blood to become so viscous that vital organs are unable to function properly
Vaccine available but only produces short term immunity
Treatment: tetracycline and replacement of lost fluids
50% mortality rate

31. Diseases of the Urinary Reproductive Systems
Cystitis: inflammation of urinary bladder
Signs and Symptoms: dysuria (Painful or difficult urination. This includes burning on urination.), pyuria (presence of leukocytes in urine)
2 most common causative agents: E-coli and S. saprophyticus
Rx.: Trimethoprim-sulfamethoxazole

32. Pylonephritis: progression of cystitis to inflammation of one or both kidneys
Signs and Symptoms: fever and flank or back pain.
Causative agent: E-coli
Complications: development of scar tissue forms in kidneys and impairs their function
Rx: intravenous, broad-spectrum antibiotics (cephalosporins)

33. Leptospirosis: disease of domestic or wild animals that can pass to humans and cause severe kidney or liver disease
Causative agent: Leptospira interrogans, spirochete, obligate aerobe
Transmission: shed in urine for extended periods. Humans become infected upon contact with urine-contaminated water, soil or animal tissue
Signs and Symptoms: Incubation period or 1-2 weeks. Fever, chills, headaches, muscular aches. Several days later, second episode of fever
Rx.: Body fights off. Antibiotics not very effective
Complications: can cause kidney failure

34. Gonorrhea: one of most common communicable diseases
Causative agent: Neisseria gonorrhoeae
Transmission: attachment of organism to mucosal cells of epithelial wall
Signs and Symptoms:
Males: painful urination, discharge of pus-containing material from urethra
If untreated, can result in sterility if testes are infected
Females: only cervix infected
Some abdominal pain later in infection due to subsequent Pelvic Inflammatory Disease

35. Complications: can become systemic infection
Transmission: any type of sexual contact
Rx: typically penicillin used but increases resistance
Current drug of choice is cephalosporin: Ceftriaxone

36. Pelvic Inflammatory Disease: bacterial infection of female pelvic organs (uterus, cervix, uterine tubes, or ovaries)
Causative agent: N. gonorrhoeae, Chlamydia
Signs and Symptoms: severe abdominal pain
Transmission: bacterial attachment to sperm cells
Rx.: combination of doxycycline and cefoxitin

37. Syphilis Causative agent: Treponema pallidum Symptoms: Primary stage:
small, hard based sore (at site of infection)
serous exudate forms in center (highly infectious)
lesion disappears w/in few weeks
Secondary stage:
skin rashes of varying appearance (widely distributed on skin, mouth, throat, cervix
lesions of rash are very infectious

38. Tertiary stage loss of patches of hair generally lasts a few weeks
becomes latent
After latency for 2-4 years, not usually infectious
Tertiary stage
usually 10 or more years after onset of latent phase
most symptoms due to immune system
cause gummas, rubbery masses of tisse that appear in many organs and sometimes on external skin
can cause extensive tissue damage
Not generally infectious
most infections today don’t progress to this stage

39. Rx: Benzathine penicillin: long acting formulation that remains effective in body for about 2 weeks