Emergence of artemisinin-based combination treatment failure in patients returning from sub-Saharan Africa with P. falciparum malaria.

BACKGROUND: Artemisinin-based combination therapies (ACTs) are recommended as first-line treatment against uncomplicated Plasmodium falciparum infection. Mutations in the PfKelch13 (PF3D7_1343700) gene led to resistance to artemisinin in Southeast Asia. Mutations in the Pfcoronin (PF3D7_1251200) gene confer reduced artemisinin susceptibility in vitro to an African Plasmodium strain, but their role in clinical resistance has not been established. METHODS: We conducted a retrospective observational study of Israeli travellers returning from sub-Saharan Africa with P. falciparum malaria, including patients with artemether-lumefantrine (AL) failure. Blood samples from all malaria-positive patients are delivered to the national Parasitology Reference Laboratory along with personal information. Confirmation of malaria, species identification and comparative parasite load analysis were performed using real-time PCR. DNA extractions from stored leftover samples were analysed for the presence of mutations in Pfkelch13 and Pfcoronin. Age, weight, initial parasitaemia level and Pfcoronin status were compared in patients who failed treatment vs responders. RESULTS: During 2009-2020, 338 patients had P. falciparum malaria acquired in Africa. Of those, 15 (24-69 years old, 14 males) failed treatment with AL. Four were still parasitemic at the end of treatment, and 11 had malaria recrudescence. Treatment failure rates were 0% during 2009-2012, 9.1% during 2013-2016 and 17.4% during 2017-2020. In all patients, the Pfkelch13 propeller domain had a wild-type sequence. We did find the P76S mutation in the propeller domain of Pfcoronin in 4/15 (28.6%) of the treatment-failure cases compared to only 3/56 (5.5%) in the successfully treated patients (P = 0.027). CONCLUSION: AL treatment failure emergence was not associated with mutations in Pfkelch13. However, P76S mutation in the Pfcoronin gene was more frequently present in the treatment-failure group and merits further investigation. The increase of malaria incidence in sub-Saharan-Africa partly attributed to the COVID-19 pandemic might also reflect a wider spread of ACT resistance.

A nationwide study of imported Plasmodium ovale and mixed infections in Israel 2008-2020.

BACKGROUND: Plasmodium ovale is a rather neglected plasmodium. Rarity, a milder disease, and diagnostic difficulties compared with P. falciparum and P. vivax have led to this situation. This study's objective is to present the epidemiological and diagnostical characteristics of imported P. ovale malaria in Israel. METHODS: Malaria is a reportable disease in Israel. All highly suspected cases are sent to the Ministry of Health central parasitology laboratory for molecular verification. We retrieved epidemiological and diagnostic data on all polymerase chain reaction (PCR)-proven P. ovale infections imported to between 2008 and 2020. RESULTS: In total, 508 malaria cases were identified, 489 monoinfections and 19 (3.7%) mixed. Fifty-one (10%) were due to P. ovale, among them 13 (25%) were mixed, comprising 68% of all mixed infections. Forty-eight of 51 (94%) underwent blood microscopy, with a sensitivity of 94% (45/48) for genus identification and 15% (7/48) for P. ovale identification. Only 8% (1/12) of mixed infections were identified as such by microscopy. Forty-two (82%) patients underwent RDTs, with a sensitivity of 69% (29/42) for genus identification, and 62% (26/42) for identifying non-falciparum infections. Cycle threshold (Ct) values of P. ovale were significantly higher compared with P. falciparum and P. vivax in both mono and mixed infections (P < 0.05, P < 0.005). Ct levels in RDT positive vs negative infections differed significantly (P < 0.05). CONCLUSIONS: P. ovale is commonly imported to Israel from Africa, with a high rate of mixed infections. The use of RDTs and microscopy is insufficient for the species-specific diagnosis of P. ovale, and must be complemented by PCR.

Molecular typing of Cryptosporidium in Israel.

Cryptosporidium is a protozoan parasite associated with gastrointestinal illness. In immune-compromised individuals, the infection may become life-threatening. Cryptosporidiosis is a mandatory-reported disease but little was known about its prevalence and associated morbidity in Israel. Currently, laboratory diagnosis is based on microscopy or copro-antigen tests and the disease is underreported. Molecular assays, which are more sensitive and specific, are now increasingly used for identification and screening. Here, the molecular epidemiology of cryptosporidiosis is explored for the first time. Samples from 33 patients infected during an outbreak of 146 laboratory confirmed cases that occurred in Haifa and Western Galilee in 2015 were genotyped, as well as samples from 36 patients sporadically infected during 2014-2018 in different regions. The results suggest that Cryptosporidium subtypes found in Israel are more similar to those reported in the neighboring countries Jordan and Egypt than in European countries. C. hominis was the predominant species in the center and the north of Israel, implicating human-to-human transmission. C. hominis IeA11G3T3 was the most prevalent subtype contributing to morbidity.