Detection of Eperythrozoon suis using the polymerase chain reaction.

Eperythrozoon suis is an extracellular red blood cell parasite that causes icteroanemia in acutely ill pigs and a variety of syndromes in chronically infected pigs. Current techniques to detect E. suis infection are limited by variability of parasitemias and antibody responses in infected animals. The polymerase chain reaction (PCR) was investigated to determine its potential as a means of detecting E. suis infection in pigs. With DNA samples extracted from either purified E. suis organisms or E. suis-infected pig blood, PCR produced an amplification product 492 base pairs in length. This amplification product hybridized successfully with the fragment of the DNA probe from which the primer sequences had been selected. Sensitivity studies indicated that the PCR protocol was capable of amplifying total genomic E. suis DNA in quantities as low as 450 pg. When PCR was used with DNA from blood samples from a splenectomized pig that had been infected with E. suis, amplification products were detectable as early as 24 hours postinfection. This preliminary analysis indicates that PCR shows promise as a means of efficiently detecting E. suis infection in pigs.