Characteristics of imported Plasmodium ovale spp. and Plasmodium malariae in Hubei Province, China, 2014–2018

Abstract

Background: There have been an increasing number of imported cases of malaria in Hubei Province in recent years. In particular, the number of cases of Plasmodium ovale spp. and Plasmodium malariae significantly increased, which resulted in increased risks during the malaria elimination phase. The purpose of this study was to acquire a better understanding of the epidemiological characteristics of P. ovale spp. and P. malariae imported to Hubei Province, China, so as to improve case management. Methods: Data on all malaria cases from January 2014 to December 2018 in Hubei Province were extracted from the China national diseases surveillance information system (CNDSIS). This descriptive study was conducted to analyse the prevalence trends, latency periods, interval from onset of illness to diagnosis, and misdiagnosis of cases of P. ovale spp. and P. malariae malaria. Results: During this period, 634 imported malaria cases were reported, of which 87 P. ovale spp. (61 P. ovale curtisi and 26 P. ovale wallikeri) and 18 P. malariae cases were confirmed. The latency periods of P. ovale spp., P. malariae, Plasmodium vivax, and Plasmodium falciparum differed significantly, whereas those of P. ovale curtisi and P. ovale wallikeri were no significant difference. The proportion of correct diagnosis of P. ovale spp. and P. malariae malaria cases were 48.3% and 44.4%, respectively, in the hospital or lower-level Centers for Disease Control and Prevention (CDC). In the Provincial Reference Laboratory, the sensitivity of microscopy and rapid diagnostic tests was 94.3% and 70.1%, respectively, for detecting P. ovale spp., and 88.9% and 38.9%, respectively, for detecting P. malariae. Overall, 97.7% (85/87) of P. ovale spp. cases and 94.4% (17/18) of P. malariae cases originated from Africa. Conclusion: The increase in the number of imported P. ovale spp. and P. malariae cases, long latency periods, and misdiagnosis pose a challenge to this region. Therefore, more attention should be paid to surveillance of imported cases of P. ovale spp. and P. malariae infection to reduce the burden of public health and potential risk of malaria.

Comparison of Plasmodium ovale curtisi and Plasmodium ovale wallikeri infections by a meta-analysis approach

“…by Sutherland et al 25 , and 2020. The majority of included studies (14/36, 38.9%) were conducted in African countries (1 in Angola 9 , 1 in Equatorial Guinea 26 , 2 in Ethiopia 5 , 8 , 2 in Gabon 43 , 51 , 1 in Ghana 15 , 1 in Kenya 46 , 1 in Namibia 44 , 2 in the Republic of Congo/Congo 26 , 42 , 2 in Senegal 6 , 7 and 1 in Uganda 26 ), Asian countries (9 in China 12 , 14 , 32 , 35 , 39 , 49 , 50 , 52 , 53 , 2 in India 10 , 11 , 1 in Bangladesh 41 , 1 in Myanmar 12 and 1 in Thailand 13 ), Europe (3 in Italy 29 – 31 , 2 in France 23 , 45 , 2 in Spain 47 , 48 , 2 in the United Kingdom 25 , 34 and 1 in Germany 40 ) and Northern America (1 in Canada 28 ). Most of the included studies 23 , 25 , 28 , 30 – 32 , 34 , 35 , 39 , 40 , 45 , 47 – 50 , 52 , 53 (19/36, 52.8%) reported indigenous cases of malaria caused by P. ovale curtisi or P. ovale wallikeri , and the remaining studies (17/36, 47.2%) reported imported cases.…”

“…The latency period in each study was calculated from the period in days between the last date in the malaria-endemic country and presentation to the hospital in the non-endemic country. Eight studies 30 , 32 , 34 , 40 , 47 , 48 , 52 , 53 reported the mean latency period (days) of P. ovale spp. and were included in the analysis.…”

“…The mean latency period of P. ovale curtisi ranged from 44.4 to 176.9 days, whereas the mean latency period of P. ovale wallikeri ranged from 20 to 123 days. The difference in the mean latency period (days) between P. ovale curtisi and P. ovale wallikeri malaria was analyzed, which showed a longer mean latency period of P. ovale curtisi (290 cases) than that of P. ovale wallikeri (265 cases) reported in four studies 47 , 48 , 52 , 53 , and a shorter mean latency period of P. ovale curtisi than that of P. ovale wallikeri was demonstrated in a study reported by Nolder et al 34 . Overall, the meta-analysis provided evidence favoring a real difference in the mean latency period between P. ovale curtisi (289 cases) and P. ovale wallikeri (266 cases) malaria cases ( p : 0.03, MD: 27.59, 95% CI 1.99–53.2, I 2 : 94%) (Fig.…”

“…The first identification of the species P. ovale wallikeri and P. ovale curtisi was reported by Sutherland et al 25 . Since then, differences in morphology, clinical characteristics, laboratory parameters and genetic differences between the two species have been observed in Africa 5 – 9 , 15 , 26 , 42 – 44 , 46 , 51 , Asia 10 – 14 , 32 , 35 , 39 , 41 , 49 , 50 , 52 , 53 , Europe 23 , 25 , 29 – 31 , 34 , 40 , 45 , 47 , 48 , and North America 28 . This widespread distribution of P. ovale spp.…”

“…This widespread distribution of P. ovale spp. has necessitated the expansion of its research to other parts of the world, due to the increasing numbers of imported cases in non-endemic countries 23 , 25 , 28 , 30 – 32 , 34 , 35 , 39 , 40 , 45 , 47 – 50 , 52 , 53 .…”