Serological evidence of human infection with the protozoan Neospora caninum

Jennifer Tranas, Robert A. Heinzen, Louis M. Weiss, Milton M. Mcallister

Research output: Contribution to journalArticlepeer-review

101 Scopus citations


Neospora caninum is a protozoan parasite that is closely related to Toxoplasma gondii. Dogs are a definitive host. Prior to its discovery in 1988, N. caninum infection in animals was often mistakenly diagnosed as toxoplasmosis. Neosporosis in animals is characterized by encephalitis, abortion, and other conditions that clinically and pathologically resemble toxoplasmosis. The potential of N. caninum to infect humans is unknown. Therefore, evidence of human exposure to this parasite was sought by screening for antibodies in blood donors by indirect fluorescent antibody (IFA) tests and immunoblotting. Of 1,029 samples screened, 69 (6.7%) had titers of 1:100 by IFA testing. Fifty of the 69 (72%) sera that were positive for N. caninum were also negative for a closely related protozoan pathogen of humans, T. gondii. Immunoblot analysis confirmed the specificity of the positive sera for N. caninum antigens, with several sera recognizing multiple Neospora antigens with molecular masses similar to those of antigens recognized by monkey anti-N. caninum serum. An immunodominant antigen of approximately 35 kDa was observed with 12 sera. These data provide evidence of human exposure to N. caninum, although the antibody titers in healthy donors were low. The significance of human exposure to, and possible infection with, this parasite is unknown and warrants further study.

Original languageEnglish (US)
Pages (from-to)765-767
Number of pages3
JournalClinical and Diagnostic Laboratory Immunology
Issue number5
StatePublished - Sep 1999

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Clinical Biochemistry
  • Microbiology (medical)


Dive into the research topics of 'Serological evidence of human infection with the protozoan Neospora caninum'. Together they form a unique fingerprint.

Cite this