Preventing laboratory-acquired Toxoplasma gondii infection: literature review and case-based post-exposure prophylaxis proposal

Occupationally acquired cases of the intracellular parasite <i>Toxoplasma gondii</i> have been reported, even though there is uncertainty on which infection prevention measures should be implemented in such event. We report a clinical case of laboratory-acquired toxoplasmosis and propose a protocol for post-exposure prophylaxis, given there are no formal guidelines. In this community case study, we describe the management and prevention protocol following an occupational laboratory exposure by a healthy 30-year-old <i>Toxoplasma</i>-seronegative female researcher who suffered an accidental needle puncture with a sample containing a genetically modified hypervirulent <i>Toxoplasma gondii</i> strain. Post-exposure prophylaxis (PEP) with trimethoprim-sulfamethoxazole was implemented for 4 weeks, during which seroconversion occurred, without any accompanying symptoms. <i>Toxoplasma</i> IgM and IgG positivity was observed 21 and 50 days after exposure, respectively, using a validated commercial electrochemiluminescence immunoassay (ECLIA, Roche). Follow-up was maintained for 1 year, during which the patient remained asymptomatic. This report highlights the importance of special care, surveillance and decision on the need for PEP upon occupational laboratory accidental exposure to <i>Toxoplasma gondii</i>. Since there are no guidelines on what the optimal PEP regimen should be, after a literature review, we propose a PEP occupational safety protocol to be implemented in laboratories that handle samples containing <i>Toxoplasma gondii</i>, either in clinical or research setting.