Table 2.

Factors that affect whether infection and disease result from accidental exposures to parasites

Factors related to the accident
 Route and characteristics of the exposure (e.g., depth of penetra tion of a needle)a
 Inoculum size
Factors related to the parasite
 Pathogenicity, virulence, and viability of the species and isolate
 Infectious dose
Factors related to the laboratorian
 Immune status in general and with respect to the particular parasite
 Status of barriers (e.g., whether exposed skin was intact)
 Actions taken after the accident (e.g., wound care, presumptive  antimicrobial therapy)
  • a Sometimes even seemingly inconsequential exposures result in infection.