Toxoplasma gondii infection in patients with lung diseases in Shandong province, eastern China

•The first case-control study to explore the association between T. gondii infection and lung diseases in China.•Patients with lung cancer have the highest T. gondii seroprevalence (26.2%).•T. gondii DNA was detected in 5.53% blood samples of patients with lung disease and 2.51% control subjects, respectively.•T. gondii infection is more likely to be present in patients with lung disease. Toxoplasma gondii, an intracellular protozoan parasite, can induce various clinical symptoms. T. gondii has been considered to play an important role in the pathogenesis of lung diseases. This survey was conducted to explore the correlation between T. gondii infection and lung diseases through a case-control study carried out in Shandong province, eastern China. In the present survey, T. gondii IgG antibodies were found in 76/398 (19.10%) of patients with lung diseases, which was significantly higher (P < 0.001) than the level found in the control subjects (35/398; 8.79%) through serological diagnosis. Patients with lung cancer have the highest T. gondii seroprevalence (26.19%), followed by Pulmonary cyst (25.00%), Tuberculosis (17.07%), Pneumonia (16.33%) and chronic obstructive pulmonary disease (COPD) (16.05%). Moreover, a semi-nest PCR targeted T. gondii B1 gene was employed to detect the T. gondii DNA in the blood samples. T. gondii DNA was detected in 5.53% blood samples of patients with lung diseases and 2.51% control subjects, respectively. The present study firstly shows that T. gondii has a high probability to infect the patients with lung diseases. Thus, the potential presence of T. gondii in patients with lung diseases should be appreciated during in the course of treatment and safeguard procedures should be implemented to protect vulnerable patients with lung diseases.