January 25, 2017


Migrant Farm Worker Gets Rare Pulmonary Virus Due To Unclean Living Conditions


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 possible.