Organic Dust Toxic Syndrome

Table of Contents

Disease Information

Overview

Other Names: ODTS; Toxic Organic Dust Syndrome (TODS); Grain fever; Pulmonary mycotoxicosis; Silo unloader’s syndrome;  Precipitin-negative farmer’s lung disease;  Mill fever; Inhalation fever; Toxic pneumonitis; Toxic alveolitis.

Responsibilities:

  • Hospital: Report by phone, fax, or mail
  • Lab: Report by phone, fax, or mail
  • Physician/Health care providers: Report by phone, fax, or mail
  • Medical Examiners: Report by phone, fax, or mail
  • Poison Control Centers: Report by phone, fax, or mail
  • Occupational Nurses: Report by phone, fax, or mail
  • Local Public Health Agency (LPHA): No follow-up required, unless outbreak occurrence

Report to the IDPH Division of Environmental Health:

Iowa Department of Public Health
Division of Environmental Health
Lucas State Office Building
321 E. 12th Street
Des Moines, Iowa 50319-0075
Phone (Mon-Fri 8 am - 4:30 pm): 800-972-2026
Fax: 515-281-4529
24-hour Disease Reporting Hotline: (For use outside of EH office hours) 800-362-2736

Organic Dust Toxic Syndrome (ODTS) is a respiratory and systemic illness that may follow exposures to heavy concentrations of organic dusts contaminated with microorganisms.  ODTS appears to result from inhaling particles and toxins produced by microorganisms such as gram negative bacteria (Pseudomonas species, Enterobacter agglomerans, and Klebsiella species), thermophilic organisms (Aspergillus fumigatus and Micropolyspora faeni), and fungi.  Endotoxins are a common component of organic dust in agriculture and may be involved in the development of ODTS.

ODTS is a general term that includes all of the following conditions:

  • Grain fever in grain elevator workers
  • Inhalation fever
  • Mill fever in cotton textile workers
  • Precipitin-negative farmer’s lung disease
  • Pulmonary mycotoxicosis
  • Silo unloader’s syndrome
  • Toxic alveolitis
  • Toxic Organic Dust Syndrome (TODS)
  • Toxic pneumonitis

ODTS may be associated with other respiratory illnesses or hazards found in similar settings, including:

  • Bronchitis
  • Farmer’s Lung or Hypersensitivity Pneumonitis (an immunologic – allergic – response involving microbial antigens in moldy hay and other materials)
  • Inhalation of toxic gases (from manure pits or other sources)
  • Silo filler’s disease (exposure to oxides of nitrogen in freshly filled silos)

A. Clinical Description

ODTS is a non-infectious, febrile illness associated with malaise, myalgia, a dry cough, dyspnea, headache and nausea which occurs after heavy organic dust exposure.  The syndrome can occur on initial exposure, and is characterized by fever occurring 4 to 12 hours after exposure and flu-like symptoms such as general weakness, headache, chills, body aches, and cough. Shortness of breath may also occur.

B. Sources of Exposure

Agricultural activities may generate a wide range of respirable dust concentrations. For example, respirable dust concentrations during bedding chopping have been measured at 1.6 to 2.5 mg/m3, whereas they may be as high as 24 mg/m3 during silo unloading.  Working in confined spaces or enclosed locations can increase dust concentrations. Various settings pose specific risks - see population at risk.

C. Population at Risk

ODTS is a fairly common illness affecting agricultural workers. An estimated 30% to 40% of workers exposed to organic dusts from grain or in enclosed livestock facilities develop the disease.  Common at risk groups include farm workers harvesting and unloading grain, especially grain that appears to be heavily contaminated with bacteria or molds; workers in hog barns or facilities, especially those using wood shavings for bedding; workers exposed to moldy straw or wood chips in other settings; poultry workers; and workers that handle compost, sort garbage, or process cotton. Exposure to endotoxin is a factor common to these otherwise diverse occupations.

Despite its common occurrence among agricultural workers, ODTS is not a widely recognized illness because only serious cases or clusters of cases are likely to come to a physician’s attention. Because many agricultural workers find it difficult to seek medical attention (or choose not to seek care) and because many physicians fall to recognize occupational respiratory diseases, ODTS is probably much more common than documented.

Organic dust exposures are a complex problem.  Of agricultural workers working with grain or in enclosed livestock facilities, 20 to 30 percent have been found to have significant changes in pulmonary function and increased respiratory symptoms. Further research is being done at places such as the High Plains Intermountain Center for Agricultural Health and Safety (HICAHS) and the Great Plains Center for Agricultural Health (GPCAH) to develop a better understanding of the causes, risks, and prevention strategies needed to protect workers.

D. Diagnosis, Treatment, and Prognosis

Listening to the chest usually reveals normal breathing sounds, and chest X-rays are usually normal. Pulmonary function may be impaired, and an increase in the number of white blood cells is common. Antibodies commonly associated with certain allergic lung diseases such as farmer’s lung are usually not present.

No specific therapy is needed to treat ODTS. However, the syndrome may often be misdiagnosed as acute bronchitis, influenza, or farmer’s lung disease, which may lead to unnecessary therapy with antibiotics or anti-inflammatory medication. It shares many clinical features with acute Farmer’s Lung and other forms of hypersensitivity pneumonitis. However, ODTS differs from acute hypersensitivity pneumonitis in several respects:  the chest X-ray does not show infiltrates, severe hypoxemia does not occur, prior sensitization to antigens in organic dust is not required and there are no known sequelae of physiological significance, such as the pulmonary fibrosis seen with chronic hypersensitivity pneumonitis. 

ODTS usually disappears within 24 hours to a few days after the worker is removed from exposure. Repeated episodes of ODTS can occur after re-exposure to contaminated organic dusts. No deaths from ODTS have been reported, although it can be a serious threat for persons with underlying health problems.

Acute episodes do not generally require treatment apart from removal from the contaminated environment and antipyretics. If symptoms persist, evaluation may be required to rule out infection, hypersensitivity pneumonitis, or other conditions. Biologic sampling to detect airborne microbials in the work environment can be costly and time consuming but is sometimes necessary to document the source of contaminated air. Inhalational fevers of all types are usually prevented by good maintenance of ventilation systems.

E. Prevention of Exposure

Minimizing Risk

Agricultural workers and employers should minimize the risk of exposure to organic dusts by taking the following precautions:

  • Be aware of the health effects of breathing organic dust. Symptoms of ODTS occur 4 to 12 hours after exposure and may include fever, weakness, headache, chills, body aches, cough, and shortness of breath.
  • Inform your doctor about recent dust exposures when seeking treatment for respiratory illness.
  • Carefully harvest and store agricultural products to minimize spoilage.
  • Use automated or mechanized equipment to move decayed materials.
  • Use local exhaust ventilation and wet methods of dust suppression to minimize exposure to organic dusts. For example, adding a quart of water to the cut side of bedding hay or straw before chopping is an effective method for reducing dust levels (but avoid overusing water).
  • Use appropriate respirators approved by National Institute for Occupational Safety and Health (NIOSH) and the Mine Safety and Health Administration (MSHA) when exposure to organic dust cannot be avoided.  For respirator guidance specific to ODTS, see “Request for Assistance in Preventing Organic Dust Toxic Syndrome”, NIOSH Publication No. 94-102. Online at www.cdc.gov/niosh/docs/94-102/pdfs/94-102.pdf.  Additional general respirator information can be found at the NIOSH Respirator website:  www.cdc.gov/niosh/topics/respirators/.
  • Do not wear contaminated work clothes inside the home. Prevent exposure of family members to dusts and other toxic materials by removing contaminated clothes outside.

In addition, use the following engineering controls to reduce dust exposure for silo unloaders:

  • Design the silo to provide for product turnover and to provide unfavorable conditions for microbial growth.
  • Design the conveyor to prevent spills of material and to ventilate dust effectively.
  • Use ventilated loading spouts when filling trucks and railroad cars with silage.

Reporting Criteria

A. Disease Reporting

Although ODTS is not hypersensitivity pneumonitis, reporting of all cases is required under the broad definition found in the current version of the Iowa Administrative Code 641—1.1(139A) Definitions: “Hypersensitivity pneumonitis” includes but is not limited to farmer’s lung, silo filler’s disease, and toxic organic dust syndrome.”   Primary responsibility for reporting falls to the physician or other health practitioner attending the patient when medical treatment is provided.

Mandatory Reporting is required of health care providers, clinics, hospitals, clinical laboratories, and other health care facilities; school nurses or school officials; poison control and information centers; medical examiners; occupational nurses. Hospitals, health care providers, and clinical laboratories outside the state of Iowa for confirmed or suspect cases in an Iowa resident.

Additional information and reporting forms can be found in the Iowa Administrative Code [641] Chapter 1, which can be accessed through a link on the IDPH EH Division Web page at www.idph.state.ia.us/eh/reportable_diseases.asp or call the IDPH Environmental Health hotline at 800-972-2026 during regular business hours.

B. References

National Institute of Occupational Health and Safety (NIOSH): Request for Assistance in Preventing Organic Dust Toxic Syndrome.  NIOSH Publication No. 94-102.  Publication date:  April, 1994.  Accessed online March 2011 at www.cdc.gov/niosh/docs/94-102/pdfs/94-102.pdf.