1. INFECTIOUS AGENTS

2. STAPHLYLOCOCCUS
Most are harmless and reside normally on the skin and mucous membranes of humans and other organisms. Some may lead to mrsa.

4. streptococcus
In addition to STREPTOCOCCAL PHARYNGITIS (strep throat), certain Streptococcus species are responsible for many cases of PINK EYE, MENINGITIS, BACTERIAL PNEUMONIA,  ENDOCARDITIS,  ERYSIPELAS, and NECROTIZING FASCIITIS  (the 'flesh-eating' bacterial infections). However, many streptococcal species are not pathogenic, and form part of the NORMAL FLORA of the mouth, skin, intestine, and upper respiratory tract. Furthermore, streptococci are a necessary ingredient in producing EMMENTALER ("swISS") CHEESE.

6. TUBERCULOSIS
Tuberculosis (TB) is an INFECTIOUS DISEASE caused by the bacterium MYOBACTERIUM TUBERCULOSIS (MTB) Tuberculosis generally affects the  LUNGS,  but can also affect other parts of the body. Most infections do not have symptoms, known as LATENT TUBERCULSOSIS. About 10% of latent infections progress to active disease which, if left untreated, kills about half of those infected. The classic symptoms of active TB are a chronic COUGH with BLOOD-TINGED SPUTUM, FEVER, NIGHT SWEATS, AND WEIGHT LOSS. The historical term "consumption" came about due to the weight loss. Infection of other organs can cause a wide range of symptoms.

7. HIV (AIDS)
HIV is a virus spread through certain body fluids that attacks the body’s immune system, specifically the CD4 cells, often called T cells. Over time, HIV can destroy so many of these cells that the body can’t fight off infections and disease. This damage to the immune system makes it harder and harder for the body to fight off infections and some other diseases. Opportunistic infections or cancers take advantage of a very weak immune system and signal that the person has AIDS.

9. ATHLETE'S FOOT
Athlete's foot (tinea pedis) is a fungal infection that usually begins between the toes. It commonly occurs in people whose feet have become very sweaty while confined within tightfitting shoes.
Signs and symptoms of athlete's foot include a scaly rash that usually causes itching, stinging and burning. Athlete's foot is contagious and can be spread via contaminated floors, towels or clothing.
Athlete's foot is closely related to other fungal infections such as ringworm and jock itch. It can be treated with over-the-counter antifungal medications, but the infection often recurs. Prescription medications also are available.

11. GONORRHEA
Gonorrhea, also spelled gonorrhoea, is a SEXUALLY TRANSMITTED INFECTION caused by the bacterium NEISSERIA GONORRHOEAE Many people have no symptoms. Men may have BURNING WITH URINATION, discharge from the PENIS, or  TESTICULAR PAIN. Women may have burning with urination,  VAGINAL DISCHARGE, vaginal bleeding between PERIODS, or PELVIC PAIN. Complications in women include PELVIC INFLAMMATORY DISEASE and in men include inflammation of the epididymis.  If untreated gonorrhea can occasionally spread to affect JOINTS OR HEART VALVES.
Gonorrhea is spread through sexual contact with an infected person. This includes oral, anal, and vaginal sex. It can also spread from a MOTHER TO A CHILD DURING BIRTH. Diagnosis is by testing the urine, URETHRA in males, or CERVIX in females Testing all women who are sexually active and less than 25 years of age each year as well as those with new sexual partners is recommended. This same recommendation applies in MEN WHO HAVE SEX WITH MEN

13. There are two types of HSV:
HERPES
Herpes is an infection that is caused by a herpes simplex virus (HSV). Oral herpes causes cold sores around the mouth or face. Genital herpes affects the genitals, buttocks or anal area. Genital herpes is a sexually transmitted disease (STD). Other herpes infections can affect the eyes, skin, or other parts of the body. The virus can be dangerous in newborn babies or in people with weak immune systems.
There are two types of HSV:
HSV type 1 most commonly causes cold sores. It can also cause genital herpes.
HSV type 2 is the usual cause of genital herpes, but it also can infect the mouth.
HSV spreads through direct contact. Some people have no symptoms. Others get sores near the area where the virus has entered the body. They turn into blisters, become itchy and painful, and then heal.
Most people have outbreaks several times a year. Over time, you get them less often. Medicines to help your body fight the virus can help lessen symptoms and decrease outbreaks

15. syphilis
You can get syphilis by direct contact with a syphilis sore during vaginal, anal, or oral sex. Sores can be found on the penis, vagina, anus, in the rectum, or on the lips and in the mouth. Syphilis can also be spread from an infected mother to her unborn baby. 
Syphilis has been called ‘the great imitator’ because it has so many possible symptoms, many of which look like symptoms from other diseases. The painless syphilis sore that you would get after you are first infected can be confused for an ingrown hair, zipper cut, or other seemingly harmless bump. The non-itchy body rash that develops during the second stage of syphilis can show up on the palms of your hands and soles of your feet, all over your body, or in just a few places. Syphilis can also affect the eye and can lead to permanent blindness. This is called ocular syphilis. You could also be infected with syphilis and have very mild symptoms or none at all.

17. lice
Head lice infect hair on the head. Tiny eggs on the hair look like flakes of dandruff. However, instead of flaking off the scalp, they stay in place.
Head lice can live up to 30 days on a human. Their eggs can live for more than 2 weeks.
Head lice spread easily, particularly among school children. Head lice are more common in close, overcrowded living conditions.
You can get head lice if:
You come in close contact with a person who has lice.
You touch the clothing or bedding of someone who has lice.
You share hats, towels, brushes, or combs of someone who has lice.
Having head lice causes intense itching, but does not lead to serious medical problems. Unlike body lice, head lice never carry or spread diseases.
Having head lice does NOT mean the person has poor hygiene or low social status.

19. Candida albicans
Candidiasis is a fungal infection caused by yeasts that belong to the genus Candida. There are over 20 species of Candida yeasts that can cause infection in humans, the most common of which is Candida albicans. Candida yeasts normally live on the skin and mucous membranes without causing infection; however, overgrowth of these organisms can cause symptoms to develop. Symptoms of candidiasis vary depending on the area of the body that is infected.
Candidiasis that develops in the mouth or throat is called "thrush" or oropharyngeal candidiasis. Candidiasis in the vagina is commonly referred to as a “yeast infection.” Invasive candidiasis occurs when Candida species enter the bloodstream and spread throughout the body. Click the links below for more information on the different types of Candida infections.

21. ringworm
Ringworm is common, especially among children. But, it can affect people of all ages. It is caused by a fungus or yeast, not a worm like the name suggests.
Many bacteria, fungi, and yeast live on your body. Some of these are useful, while others can cause infections. Ringworm occurs when a type of fungus or yeast grows and multiplies on your skin.
Ringworm can spread easily from one person to another. You can catch ringworm if you touch someone who has the infection, or if you come into contact with items contaminated by the fungus, such as combs, unwashed clothing, and shower or pool surfaces. You can also catch ringworm from pets that carry the fungus. Cats are common carriers.
The fungus that causes ringworm thrive in warm, moist areas. Ringworm is more likely when you are often wet (such as from sweating) and from minor injuries to your skin, scalp, or nails.
Ringworm can affect the skin on your:
Beard, tinea barbae
Body, tinea corporis
Feet, tinea pedis (also called athlete's foot)
Groin area, tinea cruris (also called jock itch)
Scalp, tinea capitis