Shared Flashcard Set

Details

Diseases
n/a
144
Microbiology
Undergraduate 3
12/07/2010

Additional Microbiology Flashcards

 


 

Cards

Term
Structures of the Urinary System
Definition
urethra, ureters, urinary bladder, kidneys
Term
kidneys
Definition

produce urine and filter blood

-nephrons are its functional unit, they are located in the renal pyramids of the kidneys

-appox. 1.25 million nephrons per organ

-contains glomerular (leaky capillaries)

Term
urethra
Definition

what takes urine out of the body

- much longer in males, 3x longer than in females

Term
structures of the female repoductive system
Definition

      Urinary and reproductive systems are distinct, no shared organs

          Normally urine and urinary tract above bladder are sterile

        Urethra contains normal resident flora

 

Term
normal resident flora of female reproductive tract
Definition

steptococcus, staphylococcus, cornyebacterium, lactobacillus

- normal flora varies in female repoductive tract dependent upon hormones (lactobacillus)

Term
non-venereal diseases of the reproductive tract
Definition

-affect both men and women

-urinary tract infections

-Leptospirosis

Term
urinary tract infections
Definition

          8 million cases annually in US

        600,000 nosocomial 

        Primary ascending infection, pathogens enter in through the urethra and continue up to other organs

        May include any or all of the organs

Term
urethritis
Definition
inflammation of the urethra
Term
cystits
Definition
inflammation of the urinary bladder
Term
ureteritis
Definition
inflammation of the ureter
Term
pyelonephritis
Definition
inflammation of the kidneys
Term
urinary tract infections causitive agents
Definition

        Usually intestinal flora

          E. coli – most common, about 70% of urinary tract infections

          Proteus and Klebsiella

          Pseudomonas

        Typically nosocomial 

Term
pseudomonas
Definition
associated with nosocomial infections because it causes urinary tract infections from catheters
Term

urinary tract infections signs and sympotoms

 

Definition

        Dysuria; cloudy urine with foul odor; may have pale red color from blood being lost in the urine, pain when urinating

        Tenderness of pelvic area,   May have slight fever 

        Pathogens typically ascend urethra and attach to receptors on bladder lining

        May form biofilm

Term
Pyelonephritis
Definition

        when urinary tract infection makes it to the kidneys, which makes it likely for the infection to make it into the bloodstream 

          Sudden elevation of temperature, chills, vomiting and back pain, bacteremia

Term
urinary tract infection epidemiology
Definition

        Typically results from auto-inoculation

        30% of women develop at least one UTI

        Risk factors include: short urethra; sex (males are less susceptible to UTIs); use of diaphragm; pregnancy, catheterization; women more predisposed for getting urinary tract infections

Term
prostatitis
Definition
inflammation of the prostate, when this becomes inflammed it blockes the ureters and causes a urinary tract infection in men
Term
urinary tract infection prevention
Definition

        Adequate fluid intake 

        Cranberry juice may help prevent attachment

        Void urine immediately after sex

        Proper personal hygiene

Term
urinary tract infection treatment
Definition

        Sulfonamides or cephalosporins, sulfa drugs

Term
Leptospirosis
Definition

-zoonotic disease

 

          Hard to stain, hard to grow, have a hook on the end that makes them more recognizable

Term
Leptospirosis causative agent
Definition

  Leptospira interrogans

          Gram -, Spirochete

          Double axial filaments making them very efficient at swimming and crawling

          Over 200 antigenic types

          Begins in kidneys because it comes from the bloodstream

Term
Leptospriosis signs and symptoms
Definition

        Abrupt onset of headache, spiking fever, chills and severe myalgia

        Eye redness which is directly related to the vessels that feed the eye become very dilated causing major redness.  

- ½ of patients develop nausea, vomiting and diarrhea

Term
leptospirosis characteristics
Definition

-          Requires direct contact with urine or urine contaminated waters or soil

-          Bacteria enter body through mucous membranes and breaks in skin, eventually colonizes in the kidneys

-          Organism multiplies and travels to kidneys in blood stream

        Rarely fatal, if fatal its due to renal failure or meningitis, can cause meningitis if it contacts the meninges

Term
Leptospirosis Epidemiology
Definition

        Worldwide distribution, all types of animals

        Infects, many wild and domestic animals

          Asymptomatic carriers

        Organism is excreted in urine

          Survives in water for weeks, even extremely cold water

        Farmers, ranchers, butchers, vets at high risk

Term
Leptospirosis prevention
Definition

        Avoid water contaminated with animal urine

        Maintain sanitary conditions for animals, try to prevent run off into water ways

        Vaccine available for livestock and pets

        Rodent control

Term
Leptospirosis treatment
Definition

        Oral doxycycline, chloramphenicol, erythromycin

        IV penicillin in severe cases, usually if someone is having rare complications

Term
Toxic Shock Syndrome
Definition

          May affect males (due to wounds in men) and females

        Bacterial Vaginosis

        Vaginal Candidiasis

          Staphylococcal Toxic Shock Syndrome

Term
Toxic Shock Syndrome causative agent
Definition

          Causative agent: Staphylococcus aureus

          Virulent strains produce Toxic Shock Syndrome Toxin (TSST1 or TSST2), type 1 produces the majority of toxic shock syndrome cases

        binds cells of immune system and triggers excess immune related chemicals be released, many people carry this in their mucus membranes and on the skin 

Term
Toxic Shock Syndrome Signs and Symptoms
Definition

        Sudden onset fever, chills, vomiting, diarrhea, extremely low blood pressure, mental confusion due to low blood pressure and a severe red rash

        50% mortality if untreated due to septic shock

Term
Toxic Shock Syndrome Characterisitics
Definition

          Most cases involve menstruating women

        25% of cases involved wound infection

        New mothers and surgical patients also at risk

Term
Toxic Shock Syndrome Prevention
Definition

        Avoid highly absorbent tampons, diaphragms, contraceptive sponges or use them for shorter periods of time, also change packing of a wound regularly

Term
Toxic Shock Syndrome Treatment
Definition

        Remove foreign matter or drain infected wound immediately

        IV fluids to support blood pressure

        Vancomycin (gets rid of bacteria) and anti-TSST immunoglobulin (antitoxin)

Term
Bacterial Vaginosis
Definition
no inflammation associated with it
Term
Bacterial Vaginosis causative agent
Definition

        May be caused by multiple anaerobic bacteria

        Gardnerella vaginalis: not part of normal flora but is common in environment, cannot grow in pH lower than 5

          Change in vaginal flora

        pH increases and allows overgrowth of pathogen

Term
Bacterial Vaginosis signs and symptoms
Definition

          Thin, grayish-white vaginal discharge due to anaerobic metabolism

          Can be slightly bubbly

          Pungent ‘fishy’ odor

          Some itching and irritation

          50% asymptomatic

Term
Bacterial Vaginosis prevention
Definition

          No proven prevention

          Associated with multiple sexual partners, vaginal douching, anti-microbial therapy, however, all of which will alter pH; do not want vaginal pH to change

 

 

Term
Bacterial Vaginosis Treatment
Definition

          Metronidazole: antiprotozoal drug that works on anaerobic bacterial infections, cannot be taken during pregnancy of breast feeding mothers so their only choice is vinegar douche

          Vinegar douche: this will drop the pH back where it should be

          Reestablishment of lactobacilli

Term
Vaginal Candidiasis
Definition
multitude of fungal yeast infefctions, most common type of fungal infections in humans in general
Term
Vaginal Candidiasis causative agent
Definition

          Candida albicans

          Normal flora for up to 80% of women

          Opportunistic pathogen

          Dimorphic: two different forms of growth

          Diagnosed by budding yeasts

Term
Vaginal Candidiasis signs and symptoms
Definition

          White mucoid colonies on vaginal mucus membranes and labia 

          Severe itching and burning which will increase with urination

          White curd-like discharge like cottage cheese

          Can result in serious candidasis in someone who is immunosuppressed

 

 

Term
Vaginal Candidiasis Epidemiology
Definition

          Can be spread person to person—mother to child which is rare within fungi

          Mother to newborn

          Rarely sexually transmitted

          Antibacterial medications increases risk

          Other risk factors include birth control, hormone therapy, AIDS, diabetes, invasive hospital procedures and cancers

Term
Vaginal Candidiasis characteristics
Definition

          100% of AIDS patients get candidasis due to low immune system

          Changes in vaginal flora and pH

Term
Vaginal Candidiasis Prevention
Definition
minimizing risk factors
Term
Vaginal Candidasis treatment
Definition

          Intra-vaginal treatment with nystatin and clotrimazole

          Cream azoles may weaken latex condoms by dissolving the latex

          Oral fluconazole especially used in immunosuppressed individuals

Term
Sexually transmitted diseases
Definition

          Epidemic over last 50 years

        330 million annually worldwide

          Often asymptomatic in women

        Increased risk of pelvic inflammatory disease, ectopic pregnancy, miscarriage, birth defects, sterility and cervical cancer, damage to important female parts

Term
STD Prevention methods
Definition

        Proven effective

          Sexual abstinence & mutual monogamy

        Somewhat effective

          proper, consistent condom use

          ~20% failure rate, do not prevent the spread of certain viruses

Term
Bacterial Discharge Diseases
Definition

          bacterial diseases

        Increased fluid discharge for males and females

          Gonorrhea (clap)

          Chlamydia

          co-infections ~45% of cases, if you have one you have the other

Term
Bacterial Ulcerative Diseases
Definition

        Lesions on genitals of males and females

          Syphilis

Term
Gonorrhea Causative agent
Definition

        Neisseria gonorrhoeae

          Gram-negative; diplococci

          Fimbriae and capsule makes it easy for it to attach to reproductive tract, destroys your antibodies

          Low infecting dose, just a few cells is all it takes

          White blood cells full of Neisseria that are reproducing quickly: clinical sign of gonorrhea 

Term
Gonorrhea signs and symptoms
Definition

      In men: Most men are symptomatic,    Pain on urination, discharge from penis

    In women:  Women more likely to be asymptomatic (50-80%),    Painful urination, mild discharge,  May be overlooked as UTI

    ~25% develop PID (Pelvic Inflammatory Disease)

        Less common manifestations:   Heart damage, arthritis, meningitis, UTI, pharyngitis 

 

 

Term
Antigenic Variation
Definition

          antigens change so they are not attacked or recognized by immune system (antibodies)

        protects from antibodies

Term
Gonorrhea Characteristics
Definition

          Opa proteins on fimbriae bind to T-cells

        Prevents activation of immune response

          IgA proteases

          Gonococci survive and multiply in WBCs

 

Term
Opthalmia neonatorum
Definition

          when gonorrhea is passed to child during childbirth

        Gonococcal conjunctivitis of the newborn

        Acquired from infected birth canal

        Prevented with silver nitrate or erythromycin in eyes

Term
Gonorrhea Epidemiology
Definition

        Humans only host

        Risk increases with number of sexual partners

          More common in blacks(4X) and males (slightly)

          Most cases involve adolescents with multiple partners

Term
factors that influence gonorrhea infection
Definition

          Birth control pills: by changing hormone levels it makes mucus lining of reproductive tract more likely to contract infections

          Asymptomatic Carriers

          Lack of immunity: gonorrhea changes so much your body will never figure out how to fight it

Term
Gonorrhea treatment
Definition

        No vaccine available

          Antigenic variation interferes with ability to make effective vaccine

        Doxycycline for co-infection, best choice because it treats both

        Broad spectrum cephalosporins

          Increasing number of strains resistant to numerous antibiotics

Term
Chlamydial Infections causative agent
Definition

          Chlamydia trachomatis

          Non-motile; obligate intracellular pathogen

          Gram – with no PTG

          Non-gonococcal urethritis (7 strains)

          Lymphogranuloma venereum (3 strains)

Term

   Trachoma

Definition

          Leading cause of preventable, non-traumatic blindness

Term
Trachoma signs and symptoms
Definition

       In men: Most (75%) symptomatic, Thin grayish-white discharge from penis, Sometimes epididymitis or orchitis,  May lead to sterility

        In women:  Most (85%) asymptomatic,  Increased vaginal discharge, painful urination, Risk of PID and sterile,  Increased risk of cervical cancer for adolescents

Term

  Lymphogranuloma venereum

Definition

        Severe chlamydial STD (LGV strains)

        Strains tend to be isolated to the tropics

        Characterized by genital lesion at site of infection

        Followed by bubo in groin, fever, chills, myalgia and arthritis

Term
Trachoma characteristics
Definition

          Trachoma strains multiply in cells of conjunctiva

        Kills cells and stimulates production of purulent discharge which scars conjunctiva

        Eyelids turn inward and eyelashes scar cornea

        Cornea fills with blood vessels and blindness results 

Term
Trachoma Epidemiology
Definition

        Most common reportable STD in US

        500 million cases of trachoma worldwide

          Newborns infected at birth

          Direct, indirect and vector transmission also possible

Term
Trachoma Treatment
Definition

        Azithromycin; tetracycline or erythromycin

        Doxycycline for co-infection with gonorrhea 

        Erythromycin cream in infant eyes for 10-14 days for trachoma

Term
Syphilis causative agent
Definition

        Treponema pallidum

          Narrow Gram -, spirochete

          Axial filaments

          Can’t be cultivated in artificial media

Term
Syphilis Signs and symptoms
Definition

        Occurs in numerous forms, Often confused with other diseases,    “great imitator”

       Manifestation occurs in three stages

          Primary stage

          Secondary stage

          Tertiary stage

Term
Syphilis Primary Stage
Definition

          Characterized by hard, painless, red ulcer

        Chancre

        Appears at the site of infection

          Local lymph nodes become enlarged

          Spontaneous healing of chancre

Term
Syphilis Secondary Stage
Definition

          Runny nose, watery eyes, sore throat, oral lesions, generalized aches and pains

          Non-itchy rash

        Usually on palms and soles of feet

          Spontaneous healing

Term
Syphilis tertiary stage
Definition

          Characteristic lesions called gummas

          Infection attacks other organs

          Numerous nervous system disorders

          Blindness; metal illness; stroke

Term
Congenital Syphilis
Definition

          Organism crosses placenta

          Nearly 40% result in miscarriage or stillbirth

          Begins as an early profuse nasal discharge

          Most children develop deformities

        Hutchinson’s teeth, saddle nose, sabre shins

Term
Congential Syphilis continued... 
Definition

          Organism penetrates mucous membrane and broken skin

        Low infecting dose: Less than 100 organisms

        Organism multiplies in localized area

          Chancre caused by immune response

          Spreads to lymph nodes and bloodstream

Term
Congenital Syphilis Epidemiology
Definition

        Human only host

        Transmitted via direct contact, blood transfusion, mother to fetus 

        12 million annual cases worldwide

        Maintain low incidence in US

Term
Congenital Syphilis Treatment
Definition

        VDRL test used for diagnosis

        Primary, secondary and congenital stages effectively treated with penicillin

        No proven alternative for those with penicillin allergy

        Antibiotics not effective for tertiary

Term
Viral STDs
Definition

        Herpes (viral ulcerative STD)

        Genital Warts

        AIDS

        Protozoal STD

        Trichomoniasis

Term
Genital Herpes Causitive agent
Definition

        herpes-simplex virus type 1 & 2

        Enveloped DNA virus

        Latent virus

Term
genital herpes signs and symptoms
Definition

        Genital itching and burning, fever, myalgia and malaise

        Numerous fluid filled blisters on genitals

          Burst and form lesions

        Lesions heal spontaneously

          Most patients will have recurrence

Term
genital herpes signs and symptoms continued...
Definition

          Enveloped virus fuses with host cell membrane

        Genome enters cell and begins replication

        Viruses are released by budding and cell lysis

          Blisters form when epithelial cells are killed

        Rupture to produce painful ulcerations

        Releases millions of viral particles

Term
Neonatal Herpes
Definition

        1 in 3 newborns affected if mother infected at birth

        Debilitating and potentially lethal

        Requires cesarean delivery

Term
Neonatal Herpes Epidemiology
Definition

        4 billion infected worldwide

        No animal reservoir

        Non-sexual transmission may occur

        Transmission most likely occurs during first days illness

          Transmission can happen in absence of symptoms

Term
Neonatal Herpes Treatment
Definition

        There is no cure for genital herpes

          Once infected there is lifelong risk of transmission

        Acyclovir and derivatives reduce severity

        Condoms may not be effective in prevention!!!

Term

Genital Warts (papillomas) causative agent

Definition

          Human papillomaviruses

        30 different HPV strains cause warts

        Most common STD in US

Term
Genital Warts characteristics
Definition

          Warts on genitals, vagina and cervix, Slight pain or itching may occur,  May form condylomata acuminata, Warts typically not dangerous 

        HPV linked to 99% of cervical cancers, May also cause anal, penile, vaginal and oral cancers

          HPV infects approximately 20 million people in the United States, ~ 6.2 million new cases each year,   Pap smears don’t detect HPV only abnormal cells

        DNA test is available that detects all 13 strains linked to cervical cancer

Term
Genital Warts treatment
Definition

Removal of warts by freezing, laser or acid, Typically reoccur

Term
AIDS
Definition
Acquired immunodifiency syndrome
Term
AIDS causative agent
Definition

        Human Immunodeficiency Virus (HIV)

          Most US cases causes by HIV-1

          Most African cases caused by HIV-2

        Enveloped, RNA retrovirus

Term
Signs and symptoms of AIDS (HIV disease)
Definition

        Fever; head and muscle aches; enlarged lymph nodes; rash

        Some individuals are asymptomatic for years

          AIDS is characterized by the presence of several opportunistic or rare infections and a T cell count of lower than 200/µl

Term
Signs and Symptoms of AIDS continued...
Definition

        HIV infects host cells

        RNA reverse transcribed to DNA

        DNA integrates as provirus in host chromosome

        Virus may leave genome and kill host cell

          Releases additional viruses

        Immune system becomes impaired

Term
AIDS Epidemiology
Definition

        HIV is spread mainly through sexual contact, needles or from mother to newborn

        Global pandemic         40 million cases

        ~1/3 have developed AIDS

        Sexually transmitted, and transferred through any body fluid, can infect a fetus through the placenta

Term
Global Pandemic
Definition
epidemic on more than one continent
Term
AIDS prevention
Definition

        No vaccine available: because of so many antigenic strains due to so many changes in its DNA as it multiplies, Interruption of mother to child transmission via chemotherapy

   Needle exchange programs: you bring dirty needles in and can get clean needles

        Educational programs targeting at risk populations

        Treatment of other STDs to lessen risk

Term
AIDS Treatment
Definition

        Designed to block replication and release of virus

          Generally with cocktail of medication (HAART): Highly active anti retro viral therapy

          Include reverse transcriptase inhibitors; protease inhibitors; and nucleotide analogs

Term
HAART
Definition
Highly Active Anti Retro Viral Therapy; cocktail of medication
Term
Trichomoniasis causative agent
Definition

protazoal

        Trichomonas vaginalis

        Flagellated leaf shaped protozoan with undulating membrane

        Anaerobic bacteria

 

Term
Trichamoniasis Signs and Symptoms
Definition

        Most women symptomatic: Itching of vulva and inner thighs, Itching and burning of the vagina,  Frothy, odorous yellowish-green vaginal discharge

        Most men are asymptomatic: penile discharge, pain on urination, tender testes or prostatitis

Term
Pathogenesis of Trichimoniasis
Definition

        No encysted stage so it can’t survive in environment

        Reproduces at pH of 5-6: associated with suppression of normal flora

        Reddening and swelling of vagina attributed to trauma of moving protozoan

        Frothy discharge most likely due to gas production by organism

Term
Epidemiology of Trichimoniasis
Definition

        Humans are the only known host

        Sexually transmitted or through fomites

        Worldwide distribution:   170 new cases worldwide annually,  7.5 million in US

        Most common curable STD in women

        Transmission usually sexual contact; fomites; newborns infected in birth canal

Term
Treatment of Trichomoniasis
Definition

        Single dose of metronidazole- pregnant women cannot use this because it passes thorugh breast milk and can affect the fetus

        Both partners should be treated to prevent re-infection

        Vinegar douche for pregnant or nursing women

Term
Central Nervous System (CNS)
Definition
brain and spinal cord
Term
Encephalitis
Definition
inflammation of neural tissue; associated with the brain
Term
Periperal Nervous System (PNS)
Definition

        Bundles of thin extensions from nerve cells called axons

Term
2 basic cell types
Definition
neuroglia and neurons
Term
neuroglia
Definition
provide support, help out
Term
nephrons
Definition

        Carry nerve impulses

        Nucleus in the cell body

        ganglion

Term
Nervous System Defenses
Definition

-meninges

-cerebrospinal fluid

-bone casting

-blood-brain barrier

Term
meninges
Definition

          protective covering of the brain and spinal cord, deramata (outer most layer), eranamater, piamata (cerous membrane that directly touches brain and spinal cord)

Term
meningitis
Definition
inflammation of any of the layers of the meninges
Term
Cerebrospinal fluid
Definition
fluid that fills ventricles inside the brains and is in spinal cord, it comes from the blood, it provides nuritiment
Term
Bone casting
Definition
skull and vertebrae
Term
Blood-brain barrier
Definition
physical barrier that allows very few pathogens to cross over and effect brain or spinal cord, many chemotherapeutic agents cannot cross
Term
structures of the brain and spinal cord
Definition
cerebrum, brain stem
Term
Normal flora of the nervous system
Definition

          None, Viruses can exist in a dormant state in the nervous system

        penetrate CNS by traveling up nerve bundles

        Herpes simplex and rabies viruses

Term
Nervous system bacterial diseases
Definition

        Bacterial meningitis

        Tetanus

Term
Nervous system viral diseases
Definition

        Rabies

        Viral encephalitis

Term
Streptococcus pneumoniae
Definition
leading cause in adults; pathogen of nervous system
Term

      Neisseria meningitidis 

Definition

     epidemic, fimbriae, capsule, and endotoxin

-pathogen of the nervous system 

Term

    Haemophilus influenzae

Definition

 leading cause prior to vaccine, gram negative, high plamorphic (many shapes); pathogen of nervous system

Term

        Listeria monocytogenes

Definition

 listeriosis in fetuses, pregnant women, and  immunocompromised individuals, gram positive, oval shaped (coxobacili), can contaminate dairy products, has enzymes that allow it to escape phagocytosis; pathogen of nervous system

Term

  Streptococcus agalactiae

Definition

 causes most cases of newborn meningitis, some women carry this as the normal flora in their vagina; pathogen of nervous system

Term
Meningitis signs and symptoms
Definition

        Acute high fever and severe meningeal inflammation

          Inflamed cranial meninges – severe headache, vomiting, pain

          Inflamed spinal meninges – stiff neck, altered muscle control

          Encephalitis may cause behavioral changes, coma, and death

          Petechiae may appear on skin, these are subdermal hemorrhages

Term
Meningitis Epidemiology
Definition

          S. agalactiae acquired during birth because it is carried in vaginal flora

          Listeria transmitted via contaminated food

          S. pneumoniae, Neisseria & Haemophilus all transmitted via respiratory droplets

          S. pneumoniae present in throat of 75% of humans without causing harm

          Meningococcal meningitis is the only form that becomes epidemic

Term
Meningitis Diagnosis
Definition

        Based on symptoms and culturing of bacteria in CSF from spinal tap and then culture the spinal tap

Term
Prevention of Meningitis
Definition

-dependent on pathogen

          Vaccines available for S. pneumoniae, H. influenzae, and N. meningitidis

          Individuals at risk for listeriosis should avoid high-risk foods (milk, cheeses, undercooked meat)

          Mass prophylaxis with ceftriaxone or rifampin helps control epidemics of meningococcal form

 

Term
Treatment of Meningitis
Definition

          ceftriaxone or penicillin

Term
Tetanus Signs and Symptoms
Definition

        Tightening of jaw and neck muscles

          difficulty swallowing and breathing

        Restlessness and irritability

        Increased contractions spreading to other muscles  

          Back spasms

          Difficulty breathing and death

        Prolonged contraction of diaphragm

Term
Tetanus continued...
Definition

          Bacteria contained to anaerobic tissue around wound

          Tetanospasmin toxin moves to CNS and blocks inhibition of motor neurons causing paralysis, toxins that are bound to nerves remain bond and is permanent

          50-90% mortality rate in untreated cases

Term
Epidemiology of Tetanus
Definition

        C. tetani found in dirt and dust and GI tract of humans and other animals

        Nearly half of infections result from puncture wounds including

          Body piercing, tattooing, animal bites, IV drugs

          Frequently fatal but rare in the developed world

        30 to 60 cases reported in US annually

Term
Prevention of Tetanus
Definition

        Immunization with toxiod vaccine

          DTaP

Term
Treatment of tetanus
Definition

        Thoroughly clean wound

          Remove all dead tissue and foreign material

        Penicillin to kill multiplying bacteria

          Will not destroy endospores

        Antitoxin

          Neutralizes only circulating toxin

Term
Rabies causative agent
Definition

          Causative agent: Rabies virus

          Lyssavirus family

          Enveloped ssRNA

          Spiked bullet shaped virus due to envelope it is in with spikes that help it attach to host cells

        Virus multiplies in brain forming Negri bodies ( inclusions in the brain)

Term
Signs and Symptoms of Rabies
Definition

        Pain and itching at site of infection

        Fever, headache, myalgia, sore throat, fatigue

        Progress rapidly to secondary symptoms

          Encephalitis, agitation, confusion, hallucinations, seizure, increased sensitivity to light and touch, coma

          Increased salivation and difficulty swallowing

        Results in frothing of mouth

Term
Rabies continued...
Definition

          Hydrophobia occurs in 50% of cases, this is an extreme fear of water

          About 50% of patients die within 4 days

          Virus enters through bite of an animal

          Attaches to skeletal muscle cells triggering endocytosis

          Pathogen moves across neuromuscular junction into nerve cell and travels to CNS

          Slow moving so long incubation period

        1-2 months up to several years 

          Viruses travel back to the salivary glands and are secreted in saliva

Term
Epidemiology of rabies
Definition

        Zoonotic: many animal carriers, due to vaccinations dogs are not that common

        Skunks, raccoons and bats considered chief reservoir

          75% of human cases linked to bat bites

        0 to 4 reported cases in US annually

Term
Prevention of Rabies
Definition

        Vaccination of domestic animals and Vets

        Wash wound immediately and thoroughly

          apply antiseptic

Term
Treatment of rabies
Definition

        Risk lowered if vaccine administered as soon as possible, must be vaccinated multiple times after the bite

        Interferon may be applied to wound

        No effective treatment for rabies

          Only six known survivors of disease

Term
Viral Encephalitis causative agent
Definition

spread by arthropods, most commonly mosquitos

          Causative agent: Arboviruses

          mosquitoes

        Zoonotic diseases: Horses, birds and rodents 

        West Nile encephalitis, LaCrosse encephalitis, WEE, EEE, VEE, St. Louis encephalitis

        Named based on where they are found, like VEE: Venaswaline

Term
Signs and Symptoms of Viral Encephalities
Definition

        3-7 day incubation period

        Characterized by mild flu-like symptoms

          Fever; headache; vomiting

          One or more nervous system abnormalities

        Disorientation, localized paralysis, deafness, seizures or coma

          Only minority infected develop encephalitis

          Others may develop viral meningitis

Term
Viral Encephalitis continued...
Definition

          Most reported human cases in immunosuppressd individuals

        Elderly and very young

        Healthy immune system typically fights off virus with only mild flu-like symptoms

        Viruses multiply at site of bite and in local lymph nodes

          viremia

        Virus crosses blood-brain barrier

          Damages neurons

        Causes extensive damage to brain tissue in severe cases

        Progression of disease halted by neutralizing antibody

        Mortality ranges from 2% to 50% depending of type of infecting agent and host

Term
Viral Encephalitis Epidemiology
Definition

        Disease are all zoonoses

          Maintained naturally in birds and rodents

        Humans are accidental hosts

        LaCrosse encephalitis usually causes most reported cases

        West Nile an emerging disease in US

          Appeared in New York in 1999

Term
Viral encephalitis prevention
Definition

        Eliminate vector habitat, eliminating mosquitoes

        Avoiding outdoor activities at night

        Windows and porches properly screened

        Use insect repellents and insecticides

        Vaccine available for horses

Term
Viral Encephalities treatment
Definition

        No proven antiviral therapy

Supporting users have an ad free experience!