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Flashcards in Chapter 20 Deck (13)
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1

Bacterial Meningitis (29)

-Signs & Symptoms
Sudden high fever; severe meningeal inflammation, and increased white blood cells in the CSF; inflammation causes most signs & symptoms; infection of the brain causes encephalitis; can results in brain changes, coma, and death; can develop rapidly

-Pathogens and Virulence Factors
NEISSERIA MENINGITIS
STREPTOCCUS PNEUMONIAE-MOST COMMON IN ADULTS
HAEMOPHILUS INFLUENZAE _leading cause ***
LISTERIA MONOCYTOGENES- CAN OCCUR IN PREGNAN WOMEN-FETUSES, NEWBORNS, AND ELDERLY AND IMMUNOCOMPROMISED
STREPTOCOCCUS AGALACTIA-CAUSES BACTEREMIA, PNEUMONIA, AND MENINGITIS IN NEWBORNS

Diagnosis, treatment, and prevention
Treated with intravenous antimicrobial drugs, vaccines available

2

Hansen's Disease (Leprosy) 30

-Signs & Symptoms
TUBERCULOID LEPROSY: non aggressive form of disease; strong cell-mediated immune response
LEPROMATOUS Leprosy: More virulent form, weak-cell mediated immune response

-Pathogen & Virulence Factors
MYCOBACTERIUM LEPRAE is the causative agent; distinctive slow growth rate; resistant to antimicrobial drugs

Pathogenesis: best grows in cooler regions of the body; can live inside infected cells for years; may destroy nerve and tissues

Epidemiology: Leprromatous leprosy is becoming rate; transmitted by person to person contact or breaks in the skin

Diagnosis, treatment, & Prevention
confirmed by acid fast vacilli in samples; treated with multiple antimicrobials; may be lifelong treatement; vaccine provides some protection

3

Botulism (31)

Sign & Symptoms
Intoxication with 3 manifestations: Foodborne botulism; Infant botulism (no honey if under 1 yr); Wound botulism
Progressive paralysis on both sides of the body

Pathogen & Virulence Factors
CLOSTRIDIUM BOTULINUM ; Gram positive endospore forming bacillus

Epidemiology
infant botulism most common form in US

Diagnosis, Treatment, and Prevention
3 Approaches to treatment; wash intestinal tract; administration of botulism immune globulin; antimicrobial drugs; prevented by destroying endospores in contaminated food

4

Tetanus (32)

Signs & Symptoms
TIGHTENING OF THE JAW; spasms and contractions may spread to other muscles; irregular heartbeat and blood pressure and profuse sweating may occur

Pathogen & Virulence Factors
CLOSTRIDIUM TETANI is causative agent; found in soil, dust, and the intestines of humans and animals; produce a neurotoxin called tetanospasmin

Pathogenesis:
Can aquire through break in the skin or mucous membrane

-Epidemiology
MORTALITY RATE IS 50% IF UNTREATED; INCIDENCE HAS DECREASED WORDWIDE

Diagnosis & Prevention
Diagnosis based on characteristic of muscle contraction; Vaccine is available against tetanus

5

Viral Meningitis (32)

Signs & Symptoms
Similar to those of bacterial meningitis; usually milder then those of bacterial or fungal meningitis

Pathogens & Virulence Factors
90% caused by RNA viruses in genus ENTEROVIRUS; COXSACKIE A VIRUS, COXSAKIE B VIRUS, ECHOVIRUS
Spread by fecal contamination of food, water, or hands

Pathogenesis
Damage to cells in the meninges triggers meningitis

Epidemiology
More common than bacterial and fungal meningitis; spread via respiratory droplets and feces

Diagnosis, treatment & prevention
Difficult to prevent spread of Enterovirus, no specific treatment available, characteristic signs in the absence of bacteria in CSF

6

Poliomyelitis (34) (Poliovirus)

Epedemics of Polio were common in the past; soon to be eradicated

Signs & Symptoms
ASYMPTOMATIC INFECTIONS: 90% OF CASES
MINOR POLIO; NON SPECIFIC SYMPTOMS 5% OF CASES
NONPARALYTIC POLIO: MUSCLE SPAMS AND BACK PAIN 2% OF CASES
PARALYTIC POLIO: PRODUCES PARALYSIS-LESS THEN 2%
Post polio syndrome can be debilitating

Pathogen & Pathogenesis
Poliovirus is causative Agent; transmitted by drinking water

Epidemiology
Currently exists in Africa & Asia; difficult to control because of high population and poor sanitation, and political/religious tension

Prevention
2 Effective Vaccines available

7

Rabies (35)

Sign & Symptoms
Characteristic neurological virus reaches CNS; Hydrophobia, seizures, hallucination, paralysis

Pathogen & Virulence
Rabies Virus (-ssRNA virus)

Pathogenesis
Transmitted via vite, scratch from infected animal; virus replicates in muscle cells and then moves into neurons

Epidemiology
ZOONOTIC DISEASE

Diagnosis, treatment, & prevention
Postmortem detection of NEGRI BODIES in the brain; diagnosis by unique neurological symptoms; treated with immunoglobulin, vaccine injections, and cleansing infection site; prevented by controlling rabies in domestic animals.

8

Arboviral Encephalitis (36)

ARTHROPOD-BORNE VIRUSES; transmitted by blood sucking arthropods; mosquitos*

Signs & Symptoms
Arbovirus usually cause mild, coldlike symtoms; can cause encephalitis if it crosses the blood brain barrier; can infect many different animals; 6 arboviruses cause most of the viral encephalitis in Americans; WEST NILE VIRUS IS THE MOST SIGNIFICANT IN THE US BY THE CULEX MOSQUITO

Diagnosis, Treatment, Prevention
Diagnosis based on symptoms, confirmed by arbovirus-specific antibodies in CSF; treatment is supportive; prevention involves limiting contact with mosquitos; vaccines only for horses

9

Cryptococcal Meningitis (37) (Fungal)

Signs & Symptoms
Similar to those of bacterial meningitis; loss of vision & coma may occur in later states

Pathogen & Virulence Factors
CRYPTOCOCCUS NEFORMANS is causative agent; two varients of YEAST found worldwide; RESISTS PHAGOCYTOSIS BY DEFENSIVE CELLS

Pathogenesis & Virulence Factors
Infections follow inhalation of spores or dried yest cells; occurs in terminal AIDS patients and in transplant recipients

Diagnosis, treatment, prevention
Diagnosed by detection of fungal antigen in CSF, treated with intravenous antifungal drugs; hospital try to prevent entry with air filtration

10

African Sleeping Sickness (38) (protozoan)

Signs & Symptoms
3 clinical stages; site of bite becomes lesion; parasites in the blood create fever, lymph nodes swelling, and headache; protozoa invade CNS, causing meningoencephalitis; characterized by cyclic waves of parasitemia

Pathogen & Virulence Factors
Caused by TRYPANOSOMA BRUCEI; evades immune system by changing surface glycoproteins

Diagnosis, treatment, and prevention
Diagnosed by microscopic observation of trypanosomes in blood, lymph, spinal fluid, or tissue biopsy

Treatment based on disease stage; must begin soon after infection to be successful; insecticide application can help reduce occurrence

11

Primary Amebic Meningoencephalopathy (protozoan)

Signs & Symptoms
Same as those of meningitis and encephalitis caused by other microbes

Pathogen, pathogenesis, & epidimiology
Caused by ACANTHAMOEBA AND NAEGLERIA; enter hose through abrasions on the skin or the eyelid or by inhalation of contaminated water; rare but almost always fatel

Diagnosis, treatment, and prevention
Detect amoebae in sample from the eye or brain, or in CSF, drugs have limited success; prevented by avoiding contaminated water supplies

12

Spongiform encephalopathies (40) (Prion)

Includes SCRAPIE AND "MAD COW" disease; leaves the brains of victims full of holes; can occur spontaneously in the elderly; humans can contract by eating meat from infected cattle

VARIANT CREUTZFELDT-JAKOB DISEASE
Signs & Symptoms
Insomnia, weight loss, memory failure; progressive worsening of muscle control

Pathogen, pathogenesis, and epidimiology
Caused by a abnormal form of prion protein; turn normal prions into abnormal; medical procedures can spread the disease, prions may remain dormant for years

Diagnosis, treatment, and prevention
Diagnosed by characteristic signs & symptoms; can be confused with other forms of dementia in elderly; no treatment is available; destruction of prions outside of body is difficult; prevent by avoiding prion contaminated meat

13

Trachoma (41)

Leading cause of nontraumatic blindness; scarring of conjunctiva and cornea, caused by CHLAMYDIA TRACHOMATIS multiplies in conjuctiva; purulent discharge causes deformed eyelids; scarring can lead to blindness, typically affects children