RARE DISEASE REPORT
January 25, 2017
Migrant Farm Worker Gets Rare Pulmonary Virus Due To Unclean Living
By James Radke
This week in the MMWR,
the CDC report on a confirmed case of hantavirus pulmonary syndrome
(HPS) that occurred at a Colorado farm last August.
The patient was a 25-year-old male
migrant worker, living in farm quarters, and working in vegetable fields
for 8 weeks before symptom onset.
On July 20, he experienced sudden onset
of fever, severe headache, myalgias, cough, and nosebleed. Three days
later he went to an emergency department with a temperature of 103.9°F
(40.0°C). A physical exam revealed notable bronchial breath sounds and
pulmonary crackles. Chest radiograph showed bilateral interstitial
infiltrates and small pleural effusions. Thrombocytopenia (47,000/μL)
was also observed. The patient was hospitalized for 3 days, required
minimal oxygen and supportive care, and survived.
Hantavirus Pulmonary Syndrome (HPS)
A blood test was positive for hantavirus immunoglobulin M (IgM) and
immunoglobulin G antibodies, with a positive result for Sin Nombre virus
(SNV). Most HPS cases in the United States are caused by SNV, which is
primarily transmitted by the deer mouse (Peromyscus
maniculatus) with a person being exposed to infected deer
mouse urine or droppings.
This worker was lucky. Approximately 60%
of hospitalized patients require mechanical ventilation and the HPS
case-fatality ratio is 38%.
A Mouse's Paradise
On August 17th, county officials assessed of the farm. The
worker’s residency was a 1,000 square-foot wood frame house shared by 12
other male farm workers.
The inspection found open food
containers were found throughout the house; rodent droppings were
observed in the kitchen, cement foundation, and ceiling.
The patient also reported that during
the incubation period, he took daytime naps under trees and in abandoned
farm buildings on the property. Those napping areas had evidence of
rodent habitation including nesting, burrowing, and rodent runs.
The owner of the farm agreed to
implement a pest management program following the county’s suggestion.
In 2014, a farm worker died due to HPS
and he worked at a farm 50 miles east of the new case.
The lack of a vaccine or specific
treatment for HPS underscores the importance of focusing on keeping
areas at risk for SNV (i.e., farm dwellings) as clean and mice free as