Cultivation and phylogenetic characterization of a newly recognized human pathogenic protozoan

John W. Thomford, Patricia A Conrad, Sam R. Telford, Dane Mathiesen, Barbara H. Bowman, Andrew Spielman, Mark L. Eberhard, Barbara L. Herwaldt, Robert E. Quick, David H. Persing

Research output: Contribution to journalArticlepeer-review

81 Scopus citations


An intraerythrocytic protozoan (WA1) recently isolated from a patient in Washington State was shown to be morphologically identical to Babesia microti but biologically and genetically distinct. Continuous growth of WA1 was established in stationary erythrocyte cultures. Hybridization of a chemiluminescent Babesia-specific DNA probe to Southern blots of restriction enzyme-digested genomic DNA showed that WA1 could be distinguished from other Babesia species that were antigenically cross-reactive (Babesia gibsoni and babesial parasites from desert bighorn sheep, Ovis canadensis nelsoni) or known to infect humans (B. microti, Babesia divergens, and Babesia equi), or both. A 1436-bp portion of the nuclear small subunit rRNA gene of WA1 was sequenced and analyzed. Genetic distance analysis showed that WA1 is most closely related to the canine pathogen B. gibsoni and lies within a phylogenetic cluster with Theileria species and B. equi. The methodology described will be useful for improved diagnosis and identification of human protozoal pathogens.

Original languageEnglish (US)
Pages (from-to)1050-1056
Number of pages7
JournalJournal of Infectious Diseases
Issue number5
StatePublished - May 1994

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Immunology


Dive into the research topics of 'Cultivation and phylogenetic characterization of a newly recognized human pathogenic protozoan'. Together they form a unique fingerprint.

Cite this