Mental health effects caused by red imported fire ant attacks (Solenopsis invicta)

Susceptible individuals who have suffered painful stings caused by red imported fire ants, Solenopsis invicta, usually experience physical health effects such as fever, dizziness, generalized urticaria, or other systemic reactions such as anaphylactic shock. Whether S. invicta stings also have negative effects on mental health is not clear. In the present study, the psychological impact of S. invicta stings was evaluated using a questionnaire that included a previously published posttraumatic stress disorder (PTSD) checklist, the Patient Health Questionnaire 9-item (PHQ-9), the Generalized Anxiety Disorder 7-item (GAD-7) scale, the Beck Anxiety Inventory (BAI), and the Pittsburgh Sleep Quality Index, 5th scale (PSQI(5)). A total of 96 valid questionnaires were obtained; 37 participants were placed in the stung group, and 59 participants were placed in the unstung group. Our results showed that symptoms of anxiety, depression and sleep disturbances were not associated with S. invicta stings (for GAD-7 scale, Pearson Chi-Square test, χ(2) = 0.152, df = 1, P = 0.697; for the BAI, χ(2) = 2.252, df = 1, P = 0.133; for the PHQ-9, χ(2) = 0.098, df = 1, P = 0.754; for the PSQI(5), χ(2) = 0.536, df = 1, P = 0.453). In total, 2 of 83 individuals stung by S. invicta met the criteria (>50) for PTSD. However, there was no significant difference on PTSD between those stung by S. invicta in the 30-day group and the over 30-day group (χ(2) = 0.318, df = 1, P = 0.573). Overall, our data do not show an effect of S. invicta stings on mental health as measured using a range of indicators.