Chapter 19 Microbiology

Acute Encephalitis

-Arboviruses are causative agents (EEE, LAC, SLE, West nile) -Encephalitis in newborns transmitted vertically (HSV-1, HSV-2) (Caused by mutation of PhP gene (CJD) -JC virus (Causes PML) (Seen in AIDS patients) (Treatment with zidovudine)

Meningitis

-N. meningidis (IgA protease, capsule for virulence) -S. pneumoniae (Hemolysin is a virulence factor) (Pneumococcal meningitis is most common meningitis in adults) (Prevnar (kids) and Pneumovax (adults) for prevention) -H. influenza (Diagnosis via culturing on chocolate agar) (Hib vaccine for prevention) -L. monocytogenes -C. neoformans (Chronic fungal infection) (Diagnosis via negative straining) (Most common in AIDS patients) -Coccidiodes sp. (Systemic fungal infection) (Diagnosis via identification of spherules) (Endemic to southwest regions of the U.S. -HSV, CMV, HIV (Cause aseptic meningitis)

Meningoencephalitis

-Naegleria fowleri (Microbe enters nasal passages as a result of swimming in warm bodies of fresh water) (Causes PAM leading to rapid disease) (Treatment with Amphotericin B) -Acanthamoeba (Portal of entrysis commonly broken skin) (Causes GAM)

Neonatal Meningitis

-Streptococcus agalactiae (Capsule increases virulence) -E. coli -L. monocytogenes (Prevention through avoidance of raw or unpasteurized foods) -All are transmitted vertically during birth. -All treatment with cefotaxime

Subacute Encephalitis

-Toxoplasma gondii (Infection via contact with oocysts (cats) or pseudocysts (meat) -Transmissible Spongiform Encephalopathies (TSEs) (CID or vCID) (Caused by prions through direct or vehicle transmission) -Subacute Scierosing Panencephalitis (SSPE) (Diagnosis by MRI and serology)

Tetanus

A neuromuscular disease caused by a spore forming bacterium that produces a powerful neurotoxin that leads to spastic paralysis -Characterized by spastic paralysis -Treatment involves the use of antitoxin therapy with human TIG to inactive the tetanospasm exotoxin produced by C. tetani.

Poliomyelitis

Acute enteroviral infection of the spinal cord that can cause neuromuscular paralysis

Select all of the statements that apply to acute encephalitis caused by arboviruses.

An arthropod bite is involved in transmission Insect control is the main method of prevention No satisfactory treatment exists

Botulism

An intoxication, associated with eating poorly preserved foods, which results in flaccid paralysis -Characterized by flaccid paralysis -Treatment involves the use of Type A, B, and E trivalent horse antitoxin to inactivate the exotoxin made by C. botulinum

CJD

Arboviruses, Herpes simplex vrius type 1 or 2, JC virus

Botulism

Clostridium botulinum

Tetanus

Clostridium tetani

African Sleeping Sickness

Condition by Trypanosomes spread by the tsetse fly with initial signs involving personality changes and progressing to sleep disturbances -Trypanosomiasis caused by T. brucei, which is transmitted by the tstetse fly -Infection identified by the presence of protozoans in a blood smear

Because encephalitis-causing arboviruses require an arthropod vector, acute encephalitis diseases only occur in the tropics and subtropics.

False -Arboviruses and their arthropod vectors tend to be clustered in the tropic and subtropics but many temperate zones such as the United States report periodic acute encephalitis epidemics such as West Nile encephalitis.

Select all of the statements that apply to meningoencephalitis caused by Naegleria fowleri.

Individuals are usually exposed to the amoeba when swimming in warm, natural bodies of water Naegleria meningoencephalitis is a rapidly advancing disease Naegleria meningoencephalitis treatment is usually futile

Select all of the statements that accurately describe the oral polio vaccine.

It contains three serotypes of the polio virus It is prepared from animal cell culture It contains attenuated virus

Select all of the statements that describe the inactivated polio vaccine.

It contains three serotypes of the polio virus It is prepared from animal cell culture It is the form of polio vaccine currently used in the US It contains inactivated virus

Concept of meningitis

Meningitis -droplets -Vehicles (Food; L. monocytogenes, gram positive bacterium that is resistant to cold temperatures) (Air; aerosis or droplet nuclei are examples of this type of indirect transmission) (Dust; this can come from particles in animal quarters, such as in the spread of Q fever) (soil; Coccidioides immitis, soil borne fungus) Neonatal Meningitis -Vertical route (Transmission during gestation or vaginal deliver)

Meningoencephalitis

Naegleria fowleri, Acanthamoeba

Choose the microorganism that is the causative agent of the most acute forms of bacterial meningitis in adults to test your understanding of this disease.

Neisseria meningitidis

Encephalitis

Prion

Rabies

Slow, progressive zoonotic viral disease characterized by fatal encephalitis and with hydrophobia as a symptom -Transmitted by parental route or droplet contact; HDCV used for prevention -Glycoprotein spikes: matrix protein and nucleopcapsid

Choose the microorganism that is the most common cause of bacterial meningitis in adults to test your understanding of this disease

Streptococcus pneumoniae

Subacute Encephalitis

Toxoplasma gondii, Prions

The neurotoxin produced by Clostridium tetani blocks the inhibition of muscle contraction resulting in spastic paralysis.

True -C. tetani releases a powerful neurotoxin, tetanospasmin, that binds to target sites on peripheral motor neurons, spinal cord and brain, and in the sympathetic nervous system. The toxin acts by blocking the inhibition of muscle contraction. Without inhibition of contraction, the muscles contract uncontrollably, resulting in spastic paralysis.

Select all geographic locations where West Nile Encephalitis has occurred to test your understanding of the geographical distribution of this disease.

United States Africa Middle East Parts of Asia

Select which of the following is an intoxication disease caused by Clostridium botulinum, a spore-forming anaerobe that results in flaccid paralysis of the muscles:

botulism

Polio

poliovirus

Rabies

rabies virus

Meningitis

transmission -May lead to persistent colonization -Via Droplets (Viruses: acellular pathogens, no vaccinations available) -Via Vehicles (Fungi: eukaryotic pathogens, no vaccination available) -Both droplets and Vehicles (Bacteria: prevention via vaccines against H influenza, N. meningitis, S. pneumoniae)

Polio

virus is transmitted by vehicles of the fecal oral route -IPV is used for prevention today in the U.S.