Table 4.

Numbers of reported cases of laboratory-acquired parasitic infections

ParasiteaNo. of cases counted in this article (n = 199)bNo. of cases counted by Pike (137) (n = 115)c
Blood and tissue protozoa
Trypanosoma cruzi 65
Toxoplasma gondii 4728
Plasmodiumspp.3418
Leishmania spp.124
Trypanosoma bruceisubspp.6
Trypanosomaspp.d 17
Intestinal protozoa
Cryptosporidium parvum 16
Isospora belli 35e
Giardia lamblia 22
Entamoeba histolytica 23
Helminths
Schistosomaspp.8–101
Strongyloidesspp.4f 2g
Ancylostomaspp.1f
Ascaris lumbricoides 8
Enterobius vermicularis 1
Fasciola hepatica 1 possible case1
 Hookworm2g
  • a Under each subheading (e.g., Blood and tissue protozoa), the relevant parasites are ordered in descending frequency according to the numbers of cases counted in this article.

  • b Some asymptomatic cases of Toxoplasma gondii and Trypanosoma cruzi infection were included, as were some cases in health care workers infected withCryptosporidium parvum, Giardia lamblia, andPlasmodium spp. Cases of C. parvum infection in persons exposed to naturally infected animals were not counted.

  • c The cases counted in Pike's article, which was published in 1976 (137), are listed in a separate column from the cases enumerated in this article. Pike did not provide any details or references for any of the individual cases. Therefore, the strength of the evidence for the cases could not be evaluated and potential double counting with the cases discussed here could not be eliminated. Pike counted a total of 115 cases; besides the 112 cases counted in the table, Pike counted one case of Sarcocystis infection (not listed in the table because of uncertainty about its plausibility [see the text]), one case of Chilomastix (not a pathogen) infection, and one case of infection with a Leukocytozoonsp. (not known to infect humans). Reportedly, Pike's list includes four intentional infections, but he did not specify which cases these were. Pike did not include species names; the species listed in the table presumably were the causative organisms.

  • d Pike did not clarify whether the patients were infected with Trypanosoma cruzi, T. brucei rhodesiense, or T. brucei gambiense.

  • e Pike classified these cases as cases of coccidiosis. Presumably, the etiologic agent was Isospora belli.

  • f Cutaneous larva migrans (creeping eruption or “ground itch”).

  • g Pike did not clarify whether these were cases of cutaneous larva migrans or of intestinal infection.