Chapter 19 Flashcards
What is the main virulence factor of T. brucei?
It has the ability to switch surface antigens, thus evading host-produced antibodies
What two drugs are used to treat trypanosomiasis?
Suramin and pentamidine
What is poliomyelitis?
acute enteroviral infection of the spinal cord that can cause neuromuscular paralysis
What are the initial symptoms of polio?
fever, headache, nausea, sore throat, myalgia
What genus is poliovirus in?
Enterovirus
What are the diagnostic methods for botulism?
Identifying a common food source among sick patients; cultivating C. botulinum, identifying C. botulinum in serum or wound
How can Listeriosis be diagnosed?
cold enrichment, ELISA testing, immunofluorescence testing, nucleic acid sequencing
What is Haemophilus influenzae?
A gram-negative coccobacillus that causes one of the most severe forms of human meningitis
What are the two protozoans that cause meningoencephalitis?
Naegleria fowleri and Acanthamoeba
What are the characteristics of Acanthamoeba?
large, amoeboid trophozoite, spiny psuedopods, double-walled cyst
What is rabies?
A slow, progressive zoonotic disease characterized by fatal encephalitis
What is botulism?
An intoxication associated with eating poorly preserved foods; can also occur as a true infection
What condition is caused by the JC virus in individuals with AIDS?
progressive multifocal leukoencephalopathy
What is Cryptococcus neoformans?
A fungus that causes a more chronic form of meningitis with a more gradual onset of symptoms
What is encephalitis?
Inflammation of the brain
What typically causes acute encephalitis?
viral infection
What are the neurological signs associated with “furious” rabies?
agitation, disorientation, seizures, twitching, hydrophobia
How are arboviruses diagnosed?
Serum analysis and knowledge of patient’s travel history
What is Listeria monocytogenes?
A gram-positive bacterium that ranges in morphology from coccobacilli to palisade formations and causes Listeriosis
How is meningitis caused by meningococcus differentiated from meningitis caused by pneumococcus?
Meningococcus causes petechiae; pneumococcus does not
How is CJD diagnosed?
Examination of biopsied brain or nervous tissue
What are the characteristics of N. fowleri?
small, flask-shaped amoeba with single, broad psuedopod; forms a rounded, thick-walled cyst
What diseases are caused by prions?
transmissible spongiform encephalopathies
How is polio diagnosed?
Cell cultures
How can C. neoformans be diagnosed?
negative staining, rapid tests
What are the symptoms of Zika virus in infants?
Microencephaly, vision problems, involuntary movements, seizures, irritability
How is T. brucei diagnosed?
Readily visible in blood smears, spinal fluid, and lymph nodes; serological tests
How is coccidioidomycosis diagnosed?
Observation of spherules in bodily fluids, CSF, and biopsies
What family is the Rabies virus in?
Rhabdoviridae
What type of microorganism causes the most severe forms of acute meningitis?
Bacteria
Which organism is responsible for the most serious form of acute meningitis?
Neisseria meningitidis/Meningococcus
How is N. meningitidis spread?
Through close contact with secretions or droplets
What are the signs/symptoms of meningococcemia?
Vascular collapse, hemorrhage, and petechiae
What are the characteristics of Clostridium tetani?
gram-positive, endospore-forming bacillus
What are the characteristics of S. pneumoniae?
Small, gram-positive, flattened coccus; appears end-to-end in pairs; produces an alpha-hemolysin and hydrogen peroxide
What is the portal of entry for N. meningitidis?
Upper respiratory tract
What is the gold standard for rabies diagnosis?
Direct fluorescent antibody testing
What is the recommended treatment for pneumococcal meningitis?
Vancomycin and ceftriaxone
How does botulinum toxin cause muscle paralysis?
It prevents the release of acetylcholine, the neurotransmitter that initiates the signal for muscle contraction
What is another name for tetanus?
lockjaw
What are the signs of CJD?
Altered behavior, memory loss, dementia, impaired senses, delirium, premature senility
What are the main symptoms of infant botulism?
Weak sucking action, generalized loss of tone, respiratory complications
How are arboviruses that cause encephalitis transmitted to humans?
Via vectors that feed on blood
What is tetanospasmin?
exotoxin released by C. tetani that blocks the inhibition of muscle contraction; muscles contract uncontrollably
What are prions?
Proteinaceous infectious particles that do not contain genetic material
What are the most effective drugs for treating Toxoplasmosis?
pyrimethamine, leucovorin, sulfadiazine
How does Cronobacter sakazakii cause neonatal meningitis?
Through contaminated powder formula
How is meningitis diagnosed?
Gram stain and/or culture examination of cerebrospinal fluid (CSF)
What is the main causative agent of bacterial pneumonias?
Streptococcus pneumoniae/Pneumococcus
What are the characteristics of Neisseria meningitidis?
Gram-negative, diplococci lined up side by side
What are the initial symptoms of rabies?
Fever, nausea, vomiting, headache, fatigue
What are the main signs/symptoms of acute encephalitis?
behavior changes/confusion due to inflammation, decreased consciousness, seizures, possible meningitis symptoms
What are the three major forms of botulism?
Food-borne, infant, and wound
What is meningitis?
An inflammation of the meninges that is caused by many different microorganisms
What is the morphology of Coccidioides?
moist brown or white colony with abundant, branching hyphae; fragment into arthroconidia at maturity; at warmer temperatures, germinant into a spherical cell called a spherule
How does the rabies virus appear microscopically?
Bullet-shaped
Which type of viruses are responsible for the majority of viral meningitis cases?
Enteroviruses
What is Trypanosoma brucei?
A member of the protozoan group hemoflagellates that causes African Sleeping Sickness/trypanosomiasis
What are the symptoms of Zika virus in adults?
skin rash, conjunctivitis, muscle and joint pain
What is Toxoplasma gondii?
A flagellated parasite that tends to cause thrill-seeking behaviors in infected patients
What are the typical signs/symptoms of meningitis?
Photophobia, headache, painful/stiff neck, fever, increased WBCs in CSF
What are the two most common serotypes of H. influenzae?
Hib and Hia
What are the neuromuscular symptoms of botulism?
double vision, difficulty swallowing, dizziness, muscular paralysis, respiratory compromise
What are the signs/symptoms associated with arbovirus infections?
Coma, convulsions, paralysis, tremors, loss of coordination, memory deficits, changes in speech/personality, heart disorders
What are the symptoms of trypanosomiasis?
intermittent fever, enlarged spleen, swollen lymph nodes, joint pain, personality and behavior changes, uncontrollable daytime sleepiness, nighttime sleeplessness, muscular tremors, shifting gait, slurred speech, seizures, local paralysis
What are the most common symptoms of meningitis caused by C. neoformans?
Headache, nausea, neck stiffness
Why is viral meningitis called aseptic meningitis?
Because no bacteria or fungi are found in the CSF
What is post-polio syndrome?
A condition that occurs after the initial infection with polio that results in progressive muscle deterioration
What are the neurological signs associated with “dumb” rabies?
paralyzed, disoriented, stuporous
What vector spreads trypanosomiasis?
Tsetse fly
What is botulinum toxin?
an exotoxin produced by C. botulinum that causes flaccid muscle paralysis
How are prions spread?
direct and indirect contact with infected brain tissue or CSF
What drugs are used to treat cryptococcosis?
amphotericin B, flucytosine, fluconazole
What family is the Zika virus in?
RNA virus family Flavivirus
What is a primary chancre?
The sore that forms at the site of a tsetse fly bite as the trypanosome multiplies within its new host
How is T. gondii diagnosed?
serological tests, culture, histological analysis
What is the most common cause of subacute encephalitis?
the protozoan Toxoplasma
What is bulbar poliomyelitis?
A complication of polio in which the brain stem, medulla, and cranial nerves are affected
What are the three most common causes of neonate/infant meningitis?
S. agalactiae, E. coli, and L. monocytogenes
What conditions favor Coccidioides?
High carbon and salt content in a semiarid, hot climate
What are the two components of the nervous system?
Central Nervous System (CNS) and Peripheral Nervous System (PNS)
What family is poliovirus in?
Picornaviridae
What genus is the Rabies virus in?
Lyssavirus
What are the three important functions of the nervous system?
Sensory, integrative, and motor
