Mycvir - midterm arenavirus

Lassa virus

Arenavirus isolated in Africa in 1969; causes Lassa fever.

LCM virus

First arenavirus described, in 1933.

Junin virus

Causes Argentine hemorrhagic fever.

Machupo virus

Causes Bolivian hemorrhagic fever.

Lassa fever transmission

Rodent exposure; human-to-human spread through blood, tissues, secretions, needlestick injuries, broken skin, and sexual contact.

Lassa virus reservoir

Rodents in the Muridae family; virus is shed in feces, urine, and saliva.

Lassa fever diagnosis

History and travel assessment, exclusion of malaria/other tropical fevers, isolation, and serology; ELISA detects IgM and IgG.

Lassa fever treatment

Ribavirin; the notes emphasize starting early.

Filoviruses

Enveloped viruses with negative-sense, single-stranded helical RNA.

Filovirus transmission

Contact with secretions and bodies during burial preparation; nosocomial spread can occur.

Filovirus diagnosis

RT-PCR, viral culture/isolation, and postmortem skin biopsy; electron microscopy may show long, rodlike virions.

Filovirus management

Early identification, barrier nursing, fluid/electrolyte and renal support, and management of hemorrhage and shock.

Hantaviruses

Enveloped, negative-sense single-stranded RNA viruses with three segments: S, M, and L.

Hantavirus transmission

Exposure to rodent excreta, especially feces and urine, including contaminated aerosols.

Sin Nombre virus

Hantavirus associated with hantavirus pulmonary syndrome (HPS).

Rotavirus family

Reoviridae.

Rotavirus structure

Non-enveloped, approximately 75 nm, double-layered capsid; 11 segments of double-stranded RNA.

Rotavirus transmission

Fecal-oral route.

Rotavirus incubation

1-4 days.

Rotavirus pathogenesis

Replicates in small-intestinal epithelial cells, stunting microvilli and reducing absorption.

Rotavirus symptoms

Vomiting, diarrhea, fever, abdominal pain, and sometimes respiratory symptoms.

Rotavirus diagnosis

ELISA or latex agglutination for viral antigen in stool; electron microscopy is noted but is not sensitive.

Rotavirus vaccines

RotaTeq (RV5) and Rotarix (RV1).

Caliciviridae

Virus family that includes Norovirus and Sapovirus.

Norovirus structure

Non-enveloped, icosahedral, positive-sense single-stranded RNA virus, about 27-30 nm.

Norovirus transmission

Fecal-oral, foodborne, waterborne, person-to-person, and exposure to vomitus droplets.

Norovirus infectious dose

Fewer than 100 virus particles, according to the notes.

Norovirus incubation

24-48 hours.

Norovirus symptoms

Sudden severe nausea and vomiting, sometimes low-grade fever; illness usually subsides in about 72 hours.

Norovirus diagnosis

RT-PCR; electron microscopy and immune electron microscopy are also listed. Routine culture is not possible, according to the notes.

Sapovirus

Usually causes mild to moderate gastroenteritis; more often affects infants and toddlers.

Enteric adenoviruses

Adenovirus types 40 and 41 cause gastroenteritis in infants and young children.

Astrovirus family/genus

Family Astroviridae; genus Mamastrovirus.

Astrovirus identification

Round, non-enveloped, single-stranded RNA virus with a star-like surface pattern; approximately 28-30 nm.

Astrovirus transmission and incubation

Fecal-oral/close contact; incubation is 4-5 days.

Astrovirus symptoms

Watery diarrhea lasting 1-4 days, abdominal pain, fever, anorexia, and occasional vomiting; usually milder than rotavirus.

Astrovirus diagnosis

Stool testing by EM, EIA, latex agglutination, ELISA, immunofluorescence, or multiplex NAAT.

Papovaviruses

Historical term for Papillomaviruses and Polyomaviruses.

HPV structure

Non-enveloped virus with circular, double-stranded DNA; infects cutaneous or mucosal tissues.

High-risk HPV types

HPV 16 and 18 are associated with cervical cancer; the notes also link them to oropharyngeal cancers.

HPV-2 and HPV-4

Associated with common hand warts, according to the notes.

HPV-1

Associated with plantar warts in the notes.

Genital warts

Also called condylomata acuminata or anogenital warts.

Butcher's warts

Often associated with HPV type 7; affect hands of people handling raw meat and may have a cauliflower-like appearance.

HPV diagnosis

Cytology/Papanicolaou staining and identification of koilocytes; the notes state HPV cannot be grown in cell culture.

HPV vaccines listed

Gardasil (types 6, 11, 16, 18) and Cervarix (types 16, 18), as stated in the notes.

JC virus

Polyomavirus that can cause progressive multifocal leukoencephalopathy (PML), involving CNS demyelination, especially in immunocompromised people.

BK virus

Polyomavirus associated with kidney damage, transplant complications, hemorrhagic cystitis, and nephropathy.

Merkel cell polyomavirus

MCPyV; associated with Merkel cell carcinoma, a rare skin cancer.

Trichodysplasia spinulosa-associated virus

TSPyV; associated with trichodysplasia spinulosa, especially in immunocompromised individuals.