BACKGROUND: Cryptosporidiosis is a highly transmissible parasitic diarrheal disease spread through exposure to water, food, or surfaces contaminated with feces of infected humans or animals. It has a high incidence in Nebraska (10 cases /100,000 population in 2011); one possible explanation is a high rate of occupational exposure to livestock, especially cattle. Other occupations may also have increased risk. However, the actual proportion of cases that are attributable to occupational exposures is difficult to determine from current surveillance practices. We reviewed cryptosporidiosis case reports to describe cases of potential occupational transmission.
METHODS: Reports for all laboratory-confirmed cases of cryptosporidiosis among Nebraska residents ≥15 years old that occurred from 2010–2014 were obtained from the Nebraska Electronic Disease Surveillance System. Potential occupational risk factor questions, including whether the patient works at a day care center and history of animal contact, were analyzed. Occupational information was also abstracted from free text investigation comments in the system. For cases identified as having potential occupational exposure to high risk animals, potentially infected persons, or contaminated water, we coded occupation and exposure type then calculated frequencies.
RESULTS: Occupational information was available for 118 (20.5%) of 576 cryptosporidiosis cases. Potential occupational risk was identified in 71 (12.3%) cases. Cryptosporidiosis cases with potential occupational risk, compared to cases without obvious occupational risk, were more likely to be male (49.3% vs 40.4%) and hospitalized (23.5% vs 11.1%) but these differences were not statistically significant. Of cases classified as having potential occupational risk, 62% had occupational contact with animals, 33.8% with potentially infected persons and 3.0% with water. Among cases with occupational animal contact, farmworkers (79.5%) were the most common occupation, followed by veterinarians (11.4%); cattle were the most common animal mentioned. Among cases with exposure to potentially infected persons, the most common occupations were child care workers (41.7%), hospital workers (25.0%) and workers in other healthcare facilities (20.8%).
CONCLUSIONS: At least one in every 8 cryptosporidiosis cases aged ≥15 years in Nebraska has occupational risk factors, but this could be underestimated. Clinicians should have a high index of suspicion for cryptosporidiosis among high risk workers with diarrheal diseases. Workers with potential occupational risk factors should be well educated about disease awareness, appropriate use of personal protective equipment and proper hygiene techniques at work. Occupational information needs to be collected more systematically in the surveillance system in order to completely understand the burden of occupationally acquired cases in Nebraska.