Rhabdovirus
• Nearly 100% fatal after symptoms appear• Bullet shaped virion• Helical nucleocapsid• Zoonotic• Glycoprotein Binds to Nicotinic Ach receptors in the post-synaptic junction.
Replicates in motor neurons and move retrograde• Incubation weeks to months – 1-3mm/day tingling and muscle spasm, dorsal root
ganglia• Biopsy and autopsy, Negri body – eosinophilic inclusion• Pyramidal cells of hippocampus and Purkinje cells• Passive immunization and active vaccination
• Wake up with bat, vaccination
Recent Rabies Case in Florida
• Man capture bat• Puts in on porch in container and tells his 6 year old son not to touch
it
Polio
• Naked• Acid Stable• Replicates in Peyer’s patches in ileum then disseminate to:• Anterior horn cells • Asymmetric• Three serotypes
Polio vaccine
• Salk• Killed virus• No IgA response• NO RISK of reversion to paralytic polio• NO HERD effect
• Sabin• Oral, three serotypes of attenuated polio• Has herd effect• Produces IgA• CAN revert to paralytic polio
• US uses only Salk now
Non-Polio Enteroviruses
• Many different serotype• viral conjunctivitis• hand, foot, and mouth disease• meningitis • pericarditis • acute flaccid paralysis • inflammatory muscle
• meningoencephalitis• Severe form EV-D68 in 2014 with deaths from severe respiratory
disease
Zika
• Recent attention to the virus• Flavivirus• Interesting neurologic complications and prolonged survival in semen
History
• Discovery in 1947 Zika Forest, Uganda• In 2007 febrile illness on the Yap Islands in the Federated States of
Micronesia• 2014 ZIKV Pacific Islands• 2015 ZIKV was identified for the first time in Brazil.
MMWR
• Many infants had excessive, redundant scalp skin
• Arthrogryposis (contractures of extremities)• CT scans of infants brain
• Widespread brain calcifications• Lissencephaly, Pachygyria
• All 35 infants tested negative for syphilis, toxoplasma, CMV,
• Rubella and HSV
Borrowed from Dr. Parameswaran
First case of microcephaly in infant related to Zika in Hawaii, Feb 2016
Borrowed from Dr. Parameswaran
Guillain-Barre syndrome and Zika virus
• Higher than usual numbers of patients with Guillain-Barre syndrome noted in French Polynesia during Zika virus outbreak
• The first case had evidence for infection with Zika and Dengue• Reports of increase in numbers of GBS from six countries
recently in conjunction with Zika virus outbreaks• Recent report of GBS with Chikungunya outbreak from French
Polynesia
Borrowed from Dr. Parameswaran
HSV 1 and 2
• Cold sores• Genital Lesions• Use to be able to predict on anatomy, not any more• Viral infection in most cells results in lysis and death
DS DNA
Pathogenesis
• HSV infects some neuronal cells• These cell do not die but are maintained in a repressed state called
latency• Virus can then become activated but does not damage the neuron• Release of virions from neuron follows a complex process of
anterograde transport down the length of neuronal axons• Virus then enters epithelial cells and is called reactivation
Cardinal Findings of HSV
• Painful erythematous vesicles (blisters) on an erythematous base• Clustered in appearance• Depending on the immune status of the host, the lesions can be
locally invasive• Dew drops on rose petals
Genital Disease
• First episode is generally the worst• Treatment of the primary infection has NO effect on rate of
recurrence• Women have higher incidence of developing herpes meningitis with
primary infection• Can prevent infection in discordant couples with daily suppression of
the infected partner• Prophylaxis for individual generally not recommended unless 6 or
more episodes in a 6 month period
Other Manifestations
• Aseptic meningitis• Mollaret’s meningitis• Herpetic Whitlow• Herpes Simplex Encephalitis• Herpes gladiatorum• HSV keratitis• Neonatal Herpes• Herpes in pregnancy• HSV in HIV
Diagnosis and Treatment - HSV• Diagnosis
• Mainly clinical• Tzanck smear sometime helpful
• Multinucleated giant cells• Intra-nuclear inclusion
• HSV viral culture or PCR• Serology only useful in sero-
epidemiologic circumstances but could document primary infection. Need to know about IgM and IgG
• Treatment• Acyclovir and congeners• Mechanism in next lecture
Varicella-Zoster
• Causes both chickenpox (childhood disease) and shingles• Chickenpox
• Generally mild disease but may have major complication• Fewer than 2 deaths/100,000 cases
• MUCH worse disease with complication in adults• Over 30 deaths/100,000 cases• Most from pneumonia
DS DNA
Chickenpox
• Prodrome may occur 1 to 2 days before the onset of rash• Lassitude and fever to 103˚F• Malaise, pruritus, anorexia, and listlessness• Skin manifestations
• Maculopapules, vesicles, and scabs in varying stages of evolution• Clear vesicular fluid then pustulate and scab
• “Dewdrop-like” early - rapidly become purulent
• Small 5 mm-13 mm• Central umbilication occurs as healing progresses. • First trunk and face then centrifugally• The hallmark of the infection is the appearance of lesions at all stages
Chickenpox Complications
• CNS disease• Herpes Zoster opthalmicus• Pneumonia
• 1/400 adults• Military study showed 16% of recruits had CXR abnormalities
• Only ¼ of those had cough• Only 10% had pulmonary sx to go with CXR
• Reyes syndrome with concomitant aspirin
Diagnosis and Treatment - Zoster• Diagnosis
• Mainly clinical• Tzanck smear sometime
helpful• Multinucleated giant cells• Intra-nuclear inclusion
• VZV viral culture or PCR• Culture much more “finicky”
than HSV culture
• Treatment• Acyclovir and congeners• Mechanism in next lecture