Infections COPY Flashcards
Streptococcus pyogens
is one of the most frequent bacterial pathogens of humans. It causes many diseases ranging from harmless infections of pharynx (‘strep throat’) and skin (impetigo), to serious infections like rheumatic fever.
Clostridium tetani
is a cause of a severe infectious disease called Tetanus which may develop when the bacillus gains access from the soil to the wound that provide anaerobic conditions for bacterial growth. It produces exotoxin that passes along the nerves from the wound to the spinal cord (1-3 weeks) where it stimulates motor neurons causing tonic muscle spasm -‘lockjaw’, opisthotonus, triasmus, glottal spasm and convulsions that may cause death. An effective vaccine is available
Herpes simplex
a disease caused by infection with herpes simplex virus types 1 and 2, usually characterized by painful ulcerating vesicles 3-6 mm in diameter developing around the lips (usually type 1) or in the genital area (usually type 2). Infections may also involve the eye, the brain, or the meninges. The principal mode of spread is direct contact, and once acquired infection may be recurrent (physical illness or emotional stress).
Corynebacterium diphtheriae
an acute membranous (white-gray collection of necrotic tissue, fibrin and bacteria) infection of upper respiratory tract that may produce asphyxia. The gravity of infection is related to the production of a diffusing exotoxin that may cause myocarditis.
Clostridium perfringens
is anaerobe spore forming bacilli causing common bacterial food poisoning ( no proper food refrigeration) and benign diarrheal disease or some time serious necrotizing enteritis. When C. perfringens contaminate wounds after incubation period of 2-4 days after injury it may cause gas gangrene (fatal, gas-forming necrotizing infection).
Rotavirus infection
is an RNA virus that spreads from person to person by oral-fecal route and usually infect young children, producing vomiting, fever, abdominal pain and profuse watery diarrhea (5 to 8 days) that can lead to dehydration and death if untreated.
Influenza
an acute self-limited viral respiratory disease which is distributed worldwide and often occurs in widespread epidemics. It is characterized by fever, headache, myalgia, and prostration with bronchitis and bacterial pneumonia as common complications. Two distinct viruses cause the disease: influenza virus A and B which periodically undergo changes in antigenic composition making world population become newly susceptible to disease.
Escherichia coli
beside Salmonella typhi (typhoid fever caused by contaminated water and food- dairy products and shellfish) and Salmonella dysenteriae (causes dysentery - necrotizing infection of distal small intestine and colon), this is the most frequent cause of enteropathogenic bacterial infections. this bacteria is normally present in human colon, but aggressive when present in urinary tract, or meninges. Some strains release the endotoxins and cause serious intestinal disease.
Infectious Mononucleosis
an acute infectious disease caused by the Epstein-Barr virus that most often affecting adolescents and young adults. It is usually characterized by fever, sore throat, malaise, fatigue, weakness, lymphodenopathy, hepatosplenomegaly and mononuclear leukocytosis (lymphocytes, monocytes and its immature forms).
Varicella (chicken pox)
a contagious (respiratory route) viral disease caused by the varicella-zoster virus (herpesvirus), and characterized by lesions beginning as macules, developing into vesicles, after which the virus become latent (its reactivation in ganglion cells and infection of sensory nerve causes herpes zoster -‘shingles’). The incubation period is 17-21 days followed by fever, malaise and rash. The disease is relatively benign in children but may be serious in adults.
Staphylococcus aureus
the most common cause of suppuration and abscess formation involving: skin (pimples, boils, carbuncles), joints (arthritis), and bones (osteomyelitis), and it is leading cause of ineffective endocarditis.
Mycoplasmas
are the tiniest free-living organisms known. They spread from person to person in aerosols, bind to the surface of epithelial cells in the airways, and cause an atypical pneumonia (“walking pneumonia”) characterized by peribronchiolar infiltrates of lymphocytes and plasma cells. Infection is treated with antibiotics.
Neisseria gonorrhoeae
gonorrhea, usually an infection of the is main cause of genitourinary organs. The disease is detectable three to five days after sexual contact with an infected partner, and it is usually characterized by a purulent urethral discharge in man. Symptoms are less prominent in women. If the antibiotic (penicillin) treatment is not started promptly, urethral stricture in man and fallopian tubes infection - salpingitis in women is a common complication.
Neisseria meningitidis
meningococcus is a Gram negative bacteria that causes pyogenic meningitis in children younger than 5 years of age. It is spread from one person to another primarily by respiratory droplets and as an epidemic disease occurs in crowded quarters. There are several different types: type A is a main cause of epidemic and B and C cause sporadic cases. Main characteristics are fever, headache and stiff neck and treatment require high doses of antibiotics.
Rickettsia
group of small pathogens mostly transmited between mammals by arthrop- odes (insects). They are obligated intracellular parasites that cause epidemic typhus, spotted fever etc. By injuring the endothelial cells, rickettsiae cause a hemorrhagic vasculitis that is often visible as a skin rash, but they may also cause pneumonia, hepatitis or injure CNS and cause death.
