This study aimed to elucidate the clinical characteristics of patients diagnosed with toxoplasmosis in Korea. We collected and analyzed the specific research data of 5,917 patients from the Health Insurance Review and Assessment (HIRA; 2007–2020) and 533 electronic medical records (EMRs; 2003–2021) of Korean patients. The HIRA data showed that toxoplasmosis is an endemic disease that occurs constantly in Korea, with a large proportion of patients complaining of ocular symptoms. Of the 533 patients for whom EMR data were available, 54.6% were diagnosed with toxoplasmosis; ocular toxoplasmosis (35.7%), congenital toxoplasmosis (4.7%), cerebral toxoplasmosis (4.1%), pulmonary toxoplasmosis (0.4%), and toxoplasma hepatitis (0.6%), in order of frequency. In ocular cases, 54.4% of the patients had diverse ocular pathologies. Toxoplasmosis in Korea is characterized by a high frequency of ocular symptoms, most patients are adults, and 51.8% of patients with seropositivity were positive for IgG, suggesting prior infection. This study highlights that patients with ocular symptoms are included in the major diagnosis group for acquired toxoplasmosis in Korea.

This study determined the recent status and trend of Pneumocystis jirovecii pneumonia (PcP) in the non-human immunodeficiency virus (HIV) (non-HIV-PcP) and HIV (HIV-PcP) infected populations using data from the Health Insurance Review & Assessment Service (HIRA) and the Korea Disease Control and Prevention Agency (KDCA). SaTScan and Joinpoint were used for statistical analyses. Non-HIV-PcP cases showed an upward trend during the study period from 2010 to 2021, with the largest number in 2021 (551 cases). The upward trend was similar until 2020 after adjusting for the population. Seoul had the highest number of cases (1,597) in the non-HIV-PcP group, which was the same after adjusting for the population (162 cases/1,000,000). It was followed by Jeju-do (89 cases/1,000,000). The most likely cluster (MLC) for the non-HIV-PCP group was Seoul (Relative Risk (RR)=4.59, Log Likelihood Ratio (LLR)=825.531), followed by Jeju-do (RR=1.59, LLR=5.431). An upward trend was observed among the non-HIV-PcP group in the Jeju-do/Jeollanam-do/Jeollabuk-do/Gyeongsangnam-do/Busan/Daejeon/Daegu/Ulsan joint cluster (29.02%, LLR=11.638, P<0.001) located in the southern part of Korea. Both women and men in the non-HIV groups showed an overall upward trend of PcP during the study period. Men in the 60-69 age group had the highest annual percentage change (APC 41.8) during 2014-2019. In contrast, the HIV groups showed a falling trend of PcP recently. Men in the 60-69 age group had the most decrease (APC -17.6) during 2018-2021. This study provides an analytic basis for health measures and a nationwide epidemiological surveillance system for the management of PcP.

This study was done to provide an analytical overview on the latest malaria infection clusters by evaluating temporal trends during 2010-2019 in Korea. Incheon was the most likely cluster (MLC) for all cases of malaria during the total period. MLCs for P. falciparum, vivax, malariae, ovale, and clinically diagnosed malaria without parasitological confirmation were Jeollanam-do, Incheon, Gangwon-do, Gyeongsangnam-do, and Jeollabuk-do, respectively. Malaria was decreasing in most significant clusters, but Gwangju showed an increase for all cases of malaria, P. vivax and clinically diagnosed cases. Malaria overall, P. falciparum and P. vivax seem to be under control thanks to aggressive health measures. This study might provide a sound scientific basis for future control measures against malaria in Korea.