Investigation of imported malaria cases at a COVID-19 isolation point in Qingdao

ABSTRACT

The epidemiological data were collected from travellers who returned from Guinea on the 23rd of September, 2020 and were diagnosed with malaria at a COVID-19 quarantine site in Qingdao, Shandong Province. The epidemiological characteristics, diagnosis and treatment of the cases and the epidemiology investigation and the rapid test screening results for other travellers on from the same flight and the interventions in reaction to the imported malaria cases were analyzed. The results showed that 4 out of 231 Guinean returned travellers had developed malaria symptoms, including chills and fever, during the isolation period. Rapid diagnostic test (RDT) indicated Plasmodium falciparum infection. Considering the patients' travel history, clinical manifestations, and laboratory RDT test results, a confirmed diagnosis of imported P. falciparum malaria was made. The four malaria cases, who are male workers aged 29 to 55, were transferred to Jiaozhou People's Hospital for treatment. All four patients were administrated of artemether tablets upon diagnosis. One of the cases experienced severe malaria complications and were administrated with 12 doses (60 mg/dose) of artesunate intravenously for five days. The other three patients were treated with dihydroartemisinin and piperaquine phosphate tablets for one course of 8 tablets in 2 days (40 mg dihydroartemisinin and 320 mg piperaquine phosphate), respectively. Among the 231 returned travellers, 111(48.1%) had a history of malaria overseas. There were 23 positive cases detected by RDT, including the four symptomatic cases. The other 19 cases were asymptomatic. One of the asymptomatic cases became symptomatic three months later and was diagnosed as an imported P. malariae infection. Laboratory blood smear microscopic tests at the Jiaozhou City and Qingdao Municipal Center For Disease Control and Prevention showed negative results for the four malaria cases and the 19 RDT positive case. The samples from the four malaria cases were rechecked by the provincial reference laboratory of Shandong Institute of parasitic Disease. The results were negative for malaria infection by microscopic examination but positive for P. falciparum infection by nucleic acid test. It is suggested that during the routine control of COVID-19, the awareness of COVID-19 and malaria should be established among the returned travellers from high malaria-endemic areas. The health education "gate" should be moved forward to improve the treatment compliance for malaria cases and reduce the relapse or recrudescence caused by sub-optimal treatment.