NERVOUS SYSTEM INFECTIONS Part 2

BIOL 116

[Acellular Infections] Arboviral encephalitis (eastern equine, western equine, St. Louis, West Nile, Japanese

Pathogen: EEEV, WEEV, SLEV, WNV, JEV

Signs and Symptoms: in mild cases, fever, chills, headaches, and restlessness; in serious cases, encephalitis leading to convulsions, coma, and death

Transmission: from bird reservoirs to humans (and horses) by mosquito vectors of various species

Diagnostic Tests: Serologic testing of serum or CSF

Antimicrobial Drugs: None

Vaccine: human vaccine available for JEV only; no vaccines available for other arboviruses

[Acellular Infections] Creutzfeldt-Jacob Disease and other TSEs

Pathogen: prions

Signs and Symptoms: memory loss, confusion, blurred vision, uncoordinated movement, insomnia, coma, death

Transmission: exposure to infected nerve tissue via consumption or transplant, inherited

Diagnostic Tests: tissue biopsy

Antimicrobial Drugs: none

Vaccine: none

[Acellular Infections] Poliomyelitis

Pathogen: Poliovirus

Signs and Symptoms: asymptomatic or mild nausea, fever, headache in most cases; in neurological infections, flaccid paralysis and potentially fatal respiratory paralysis

Transmission: fecal-oral route or contact with droplets or aerosols

Diagnostic Tests: culture of poliovirus, PCR

Antimicrobial Drugs: none

Vaccine: attenuated vaccine (Sabin) killed vaccine (Salk)

[Acellular Infections] Rabies

Pathogen: Rabies virus (RV)

Signs and Symptoms: fever, headaches, hyperactivity, hydrophobia, excessive salivation, terrors, confusion, spreading paralysis, coma, always fatal if not promptly treated

Transmission: from bite of infected mammal

Diagnostic Tests: viral antigen in tissue, antibodies to virus

Antimicrobial Drugs: attenuated vaccine, rabies immunoglobulin

Vaccine: attenuated vaccine

[Acellular Infections] Viral meningitis

Pathogen: HSV-1, HSC-2, varicella zoster virus, mumps virus, influenza virus, measles virus

Signs and Symptoms: nausea, vomiting, photophobia, stiff neck, confusion, symptoms generally resolve within 7-10 days

Transmission: sequela of primary viral infection

Diagnostic Tests: testing of oral, fecal, blood, or CSF samples

Antimicrobial Drugs: varies depending on cause

Vaccine: varies depending on cause

[Acellular Infections] Zika virus infection

Pathogen: Zika virus

Signs and Symptoms: fever, rash, conjunctivitis; in pregnant women, can cause fetal brain damage and microcephaly

Transmission: between humans by Aedes spp. Mosquito vectors, also may be transmitted sexually or via blood transfusion

Diagnostic Tests: Zika virus RNA assay, Trioplex RT-PCR, Zika MAC-ELISA test

Antimicrobial Drugs: none

Vaccine: none

[Neuromycoses] Aspergillosis

Pathogen: Aspergillus fumigatus

Signs and Symptoms: meningitis, brain abscesses

Transmission: dissemination from respiratory infection

Diagnostic Tests: CSF, routine culture

Antimicrobial Drugs: Amphotericin B, voriconazole

[Neuromycoses] Candidiasis

Pathogen: Candida albicans

Signs and Symptoms: meningitis

Transmission: oropharynx or urogenital

Diagnostic Tests: CSF, routine culture

Antimicrobial Drugs: Amphotericin B, flucytosine

[Neuromycoses] Coccidioidomycosis (Valley fever)

Pathogen: Coccidioides immitis

Signs and Symptoms: meningitis (in about 1% of infections)

Transmission: dissemination from respiratory infection

Diagnostic Tests: CSF, routine culture

Antimicrobial Drugs: Amphotericin B, azoles

[Neuromycoses] Cryptococcosis

Pathogen: Cryptococcus neoformans

Signs and Symptoms: meningitis, granuloma formation in brain

Transmission: inhalation

Diagnostic Tests: negative stain of CSF, routine culture

Antimicrobial Drugs: Amphotericin B, flucytosine

[Neuromycoses] Histoplasmosis

Pathogen: Histoplasma capsulatum

Signs and Symptoms: meningitis, granulomas in the brain

Transmission: dissemination from respiratory infection

Diagnostic Tests: CSF, routine culture

Antimicrobial Drugs: Amphotericin B, itraconazole

[Neuromycoses] Mucormycosis

Pathogen: Rhizopus arrhizus

Signs and Symptoms: brain abscess

Transmission: nasopharynx

Diagnostic Tests: CSF, routine culture

Antimicrobial Drugs: Amphotericin B, azoles

[Parasitic Diseases] Granulomatous amoebic encephalitis (GAE)

Pathogen: Acanthamoeba spp., Balamuthia mandrillaris

Signs and Symptoms: inflammation, lesions in CNS, almost always fatal

Transmission: freshwater amoeba invade CNS via breaks in skin or sinuses

Diagnostic Tests: CT scan, MRI, CSF

Antimicrobial Drugs: Fluconazole, miltefosine, voriconazole

[Parasitic Diseases] Human African trypanosomiasis

Pathogen: Trypanosoma brucei gambiense, T. brucei rhodesiense

Signs and Symptoms: Chancre, Winterbottom's sign, undulating fever, lethargy, insomnia, usually fatal if untreated

Transmission: protozoan transmitted via bite of tsetse fly

Diagnostic Tests: blood smear

Antimicrobial Drugs: pentamidine and suramin (initial phase); melarsoprol and eflornithine (final phase)

[Parasitic Diseases] Neurocysticercosis

Pathogen: Taenia solium

Signs and Symptoms: brain cysts, epilepsy

Transmission: ingestion of tapeworm eggs in fecally contaminated food or surfaces

Diagnostic Tests: CT scan, MRI

Antimicrobial Drugs: albendazole, praziquantel, dexamethasone

[Parasitic Diseases] Neurotoxoplasmosis

Pathogen: Toxoplasma gondii

Signs and Symptoms: brain abscesses, chronic encephalitis

Transmission: protozoan transmitted via contact with oocytes in cat feces

Diagnostic Tests: CT scan, MRI, CSF

Antimicrobial Drugs: Pyrimethamine, sulfadiazine, folinic acid

[Parasitic Diseases] Primary amoebic meningoencephalitis (PAM)

Pathogen: Naegleria fowleri

Signs and Symptoms: headache, seizures, coma, almost always fatal

Transmission: freshwater amoeba invade brain via nasal passages

Diagnostic Tests: CSF, IFA, PCR

Antimicrobial Drugs: Miltefosine (experimental)

microcephaly

deformity characterized by an abnormally small head and brain, women infected by the Zika virus during pregnancy may give birth to children with this condition

Emerson respiratory (iron lung)

used to help some polio victims to breathe

prion disease

proteins that are infectious, defect in destroying malformed proteins