Case 88: Sin Nombre Virus (Hantavirus)

Question 1

what are the characteristics of the sin nombre virus genome?

Answer 1

bunyaviridae family; hantavirus genus

enveloped, triple segmented, helical, (-) sense ssRNA virus

Question 2

what is the clinical presentation of someone with sin nombre virus?

Answer 2

• fever
• muscle aches
• malaise
• shortness of breath
• weakness

3 weeks before, the patient was in a rural campsite in New Mexico where there were lots of deer mice around

Question 3

what would the PE of a sin nombre virus patient show?

Answer 3

crackles in the lungs

tachycardia

elevated respiration rate

low BP

Question 4

what would the CBC of a sin nombre virus patient show?

Answer 4

Htc: 56%

WBC: really elevated

WBC differential: 22% bands

low platelets

Question 5

what would a chest x-ray of a sin nombre virus patient show?

Answer 5

bilateral interstitial infiltrates with hilar indistinctness

this would explain the crackling in the lungs!

Question 6

where do hantaviruses replicate?

Answer 6

cytoplasm

they’re RNA viruses!

Question 7

how do you diagnose hantaviruses?

Answer 7

1. detection of hantavirus-specific IgM
2. rising titers of hantavirus-specific immunoglobulin G
3. detection of hantavirus-specific ribonucleic acid sequences by RT-PCR

Question 8

how do hantaviruses infect humans?

Answer 8

human infection is strongly associated with rodent urine or droppings in a
tight environment (e.g., under a tent in a remote campsite)

transmission can occur
when dried materials contaminated by rodent excreta are disturbed and inhaled

Question 9

what is the incubation of hantaviruses?

Answer 9

incubation period after exposure to infective rodent droppings is 1 to 5 weeks

Question 10

what is the pathogenesis of hantaviruses?

Answer 10

b3 integrins are the cellular receptors for pathogenic hantaviruses

TNF and IL-2 are involved in the pathogenesis of HPS

activated CD8+ T
cells produce holes in infected pneumocytes

nonspecific prodrome consists of fever,
chills, myalgia, headache, and GI symptoms

prodrome is followed by
bilateral interstitial pulmonary infiltrates and respiratory compromise

thrombocytopenia and a left shift (>15% bands) is almost always evident

an increase in nuclear permeability causes plasma leakage into alveolae,
producing pulmonary edema and hemoconcentration.

in the most severe cases, DIC can develop

Question 11

what is the treatment for hantaviruses?

Answer 11

supportive therapy with aggressive ventilator management and systemic vasopressors

antiviral agent ribavirin has not been
shown to be effective for pulmonary syndrome caused by Sin Nombre virus

Question 12

how do we prevent hantaviruses?

Answer 12

no vaccines available

since rodent exposure in endemic areas is critical to the development of HPS, limiting
such exposure should be the primary focus of efforts, including rodent control,
preventing entry of rodents into indoor areas, and proper clean-up of rodent-infested
areas