˜Followed by other symptoms

ØConfusion, sleepiness, light sensitivity, possible progression to convulsion and coma

˜Less common but more severe than viral meningitis, due to production of bacterial toxins

Early diagnosis and treatment is essential to prevent permanent neurological damage

Caused by Neisseria meningitides

Early diagnosis and treatment is essential to prevent permanent neurological damage

˜Gram-negative, aerobic diplococcus

˜Depending on geographic location, 20% of the population are asymptomatic carriers—nose and throat

˜Vaccination—2 months of age—followed by three or four boosters

˜Transmission: Person-to-person or respiratory droplets

˜Sudden onset  after 1-3 days of incubation

˜Antibiotic therapy reduces mortality rate by 9% to 12%

˜Aerobic gram-negative coccobacillus

˜Commonly present in normal flora of the throat

˜Vaccine available

˜Has declined in children (vaccine)

˜Causes approximately 5% to 10% of bacterial meningitis cases in adults

˜Transmission: Direct contact with respiratory droplets from a carrier or a patient

˜Has declined in children (vaccine)

˜Causes approximately 5% to 10% of bacterial meningitis cases in adults

˜Intravenous antibiotics as soon as disease is suspected

˜Gram-positive, encapsulated, facultative anaerobic diplococcus

˜Carried in throat of many healthy individuals

˜Approximately 90 different serotypes

˜Cause of otitis media

ØMillions of cases annually

˜Cause of pneumonia

Ø~500,000 cases per year in the U.S.

˜Conjugated vaccine available

˜Listeria monocytogenes

˜Foodborne illness

˜Can spread from bloodstream to CNS, causing meningitis, especially in elderly and immunocompromised persons

˜Symptoms include fever, personality change, tremors, seizures

˜Infection through contaminated food

˜Acute, often fatal illness

˜Prolonged contracting of skeletal muscle fibers, resulting in rigidity and convulsive spasms

˜Clostridium tetani—neurotoxin (exotoxin)

˜Spores found in soil, intestines, and feces of horses, sheep, cattle, dogs, cats, rats, guinea pigs, chickens

˜Spores enter human body via a wound as small as a scratch

˜Rare, serious illness caused by C. botulinum

˜Spore-forming rod—produces potent neurotoxin

Serotypes A–H

˜Four types

ØFoodborne

ØInfant

ØWound

ØInhalation

˜Incidence of disease is low, but mortality rate is high if not treated immediately and properly

˜Chronic, slowly progressive

˜Caused by Mycobacterium leprae

˜Incidence of disease is low, but mortality rate is high if not treated immediately and properly

˜Affects the skin; peripheral nerves primarily in hands and feet; and mucous membranes of nose, throat, and eyes

˜Transmission not completely understood; probably due to close contact via respiratory droplets

ØHaemophilus influenzae

ØVarious microbes

ØAssociated with unsanitary contact lenses

ØTransmitted to a newborn’s eyes during passage through the birth canal

ØPrevented by treatment of a newborn's eyes with antibiotics

˜Caused by bacteria, viruses, allergies, chemicals, or a foreign object

˜Inflammation or infection of transparent membrane that lines eyelid and part of eyeball

˜Most common symptoms include redness, itchiness, roughness, discharge, tearing

˜Treatment with antibiotic drops or eye ointment

˜Good hygiene is best way to control spread

˜Infection occurs in birth canal

˜Damage to eyelids and cornea

˜Potential vision loss

Antibiotic ointments

˜Can be caused by number of bacteria

˜Viral infection frequently complicated by secondary bacterial infection

˜Excessive exudate causes pressure against ossicles and tympanic membrane

ØCan cause membrane to rupture

˜Relatively common

˜Usually not as serious as bacterial meningitis

˜Called aseptic meningitis

˜Usually spread by direct contact with infected feces or nose and throat secretions

˜Symptoms include fever, headache, stiff neck, tiredness, rash, sore throat, and vomiting

˜Mosquitoes can be vectors and transmit viral meningitis

˜No treatment; in most cases immune system will produce antibodies to destroy virus

˜Cause: Poliovirus—small, nonenveloped, mRNA virus

˜Replicates in GI tract, shed in feces

˜Person-to-person transmission through oral-fecal route

˜Approximately 95% of cases asymptomatic

˜Approximately 4% to 8% mild infection

˜Abortive poliomyelitis results in complete recovery in less than a week

˜Risk factors for infection and effect on the severity of the disease

ØImmune deficiency

ØMalnutrition

ØTonsillectomy

ØIntramuscular injection

ØPregnancy

˜In U.S. only IPV available for routine polio vaccine for children

˜Preventable zoonotic caused by rabies virus

˜Capable of causing acute encephalitis

˜Reservoir: Raccoons, skunks, foxes, coyotes

˜Can be spread to domestic farm animals, groundhogs, weasels, dogs, and cats

˜Transmission—saliva from infected host

˜Symptoms

ØFatigue 

ØMuscle aches

ØAnxiety

ØIrritability

Agitation

ØInsomnia

ØHeadache

ØNausea

ØVomiting

Abdominal pain

˜Preexposure vaccination

˜Postexposure vaccination

˜Transmission between a susceptible vertebrate host and mosquitoes, ticks

˜Human arboviruses

ØTogaviridae

ØFlaviviridae

ØBunyaviridae

ØTransmission via infected mosquito

ØSymptoms develop 3 to 10 days after bite and include fever, headache, irritability, restlessness, drowsiness, anorexia

Ø~One third will die from disease

ØTransmitted by mosquitos

ØRange of illnesses from no symptoms to fatality

ØSymptoms occur 5 to 10 days after bite

ØNo licensed vaccine available and no specific treatment

ØMosquito borne

ØFatality rate ranges from 3% to 30%

ØMajority are subclinical or a mild illness with fever and headache

ØRare viral infection spread by mosquitoes

ØUsually affects children

ØUsually mild illness with nausea, headache, vomiting; severe cases can cause seizures, coma, paralysis, and brain damage

ØTransmitted by mosquitoes

ØSymptoms include skin rash, headache, fever, diarrhea, nausea, vomiting, back and muscle aches, lack of appetite, and swollen lymph glands

ØIn <1% of cases the virus can cause serious neurological infection

ØMost victims will recover without treatment and even those patients with neurological infections usually need only supportive therapy such as intravenous fluids and pain relievers

˜Polyomavirus JC

˜Immunocompromised vulnerability

˜Inflammation of white matter

˜Demyelination of cells in CNS

˜Treatment drugs have high toxicity

˜Treatment—increase effectiveness of immune system

ØRare infection caused by C. neoformans

ØFound in soil, especially contaminated with bird droppings

ØEnters body through inhalation or wound and can cause:

•Wound or cutaneous cryptococcosis

•Pulmonary cryptococcosis

•Cryptococcal meningitis

ØCause by Toxoplasma gondii

ØMost people asymptomatic

ØSerious infections in immunocompromised persons

ØTransmission via oral or transplacental route due to consumption of undercooked meat contaminated with cysts

ØSymptoms include speech difficulties, seizures, confusion, lethargy

ØAlso called sleeping sickness

ØCaused by Trypanosoma brucei

ØEnters bloodstream and travels to CNS, where it can cause meningitis or encephalitis

ØMain symptom is coma

ØAlso called American trypanosomiasis

ØTransmission by bite of a reduviid (“kissing bug”)

ØMay produce granulomas in CNS

Also called transmissible spongiform encephalopathies

˜Group of rare, infectious, fatal, and progressive neurodegenerative diseases

˜Causative agents are prions, molecules that begin as normal protein but abnormally fold and become infectious particles

˜Long incubation, usually years

˜In humans, impairs brain function, causing memory and personality changes, dementia, and movement disorders

•Rare, degenerative, fatal brain disorder

•No treatment to cure or control, only alleviate symptoms and relieve involuntary muscle movements

•Rare and fatal human neurodegenerative condition

•Affects younger persons than CJD with longer duration of illness

•Rare form of TSE due to defective gene encoding the prion protein and is identified by particular multicentricamyloid plaques (predominantly in the frontal lobe) in the brain

•No treatment

Rare disease that interferes with sleep

•Leads to deterioration of mental and motor functions

•Death occurs within a few months to a few years

•Endemic, fatal disease among tribe in Papua New Guinea

Caused by practice of cannibalism and eating brain tissue

ØBovine spongiform encephalopathy

ØChronic wasting disease

ØScrapie

ØTransmissible mink encephalopathy

ØFeline spongiform encephalopathy

ØUngulate spongiform encephalopathy