Epidemiological characteristics and laboratory testing of Plasmodium falciparum malaria in Hubei Province from 2020 to 2024

doi:10.12140/j.issn.1000-7423.2026.02.018

Abstract

Abstract:

Objective To investigate the epidemiological characteristics, clinical manifestations and laboratory tests of Plasmodium falciparum malaria in Hubei Province from 2020 to 2024, so as to provide insights into prevention of development of severe and fatal cases. Methods Data pertaining to P. falciparum malaria cases reported in Hubei Province from 2020 to 2024 were collected from the National Notifiable Disease Reporting System and the National Parasitic Disease Control Information Management System. The temporal, spatial and population distributions, healthcare-seeking behaviors and laboratory testing of P. falciparum malaria cases were statistically analyzed. Results A total of 251 P. falciparum malaria cases were reported in Hubei Province from 2020 to 2024, including 250 imported cases (99.60%, 250/251) and one case caused by blood transfusion, and 31 severe cases (12.35%, 31/251) and 2 deaths (0.80%). P. falciparum malaria consisted 68.02% (251/369) of all malaria cases, and the proportion of P. falciparum malaria cases in all malaria cases varied in years (χ² = 35.431, P < 0.01). The majority of imported P. falciparum malaria cases acquired infections from Africa (98.80%, 247/250), with the Democratic Republic of Congo (65 cases), Nigeria (46 cases), and Guinea (19 cases) as three largest sources of importation. The largest number of reported P. falciparum malaria cases was found in January, with males aged 31 to 50 years as the predominant demographic. Wuhan City (86 cases), Huangshi City (41 cases), and Yichang City (33 cases) as the three most highly affected cities, and P. falciparum malaria cases were reported in 70.87% (73/103) of counties (districts). The proportion of definitive diagnosis of P. falciparum malaria cases was74.90% (188/251) at initial diagnosis, and lower proportions were observed at village clinics (1/13) and among private practitioners (1/8). The proportions of definitive diagnosis of P. falciparum malaria cases were 73.08% (19/26), 89.22% (91/102), 81.93% (68/83), and 25.00% (10/40) at provincial-, city-, county-, and township and lower-level medical institutions, respectively (χ² = 66.325, P < 0.01). The median interval from disease onset to healthcare seeking was 1 day among P. falciparum malaria cases, with 54.18% (136/251) seeking healthcare services within 1 day of onset and 81.67% (205/251) within 3 days, and the median interval from healthcare seeking to definitive diagnosis was 1 day, with 65.74% (165/251) confirmed within 1 day of seeking healthcare services and 88.45% (222/251) within 3 days. Fever was the most frequent symptom (98.41%, 247/251), and other common symptoms included chills (57.37%, 144/251), sweating (42.23%, 106/251), headache (47.41%, 119/251), and myalgia (10.36%, 26/251). Complications occurred in 16.33% (41/251) of subjects, including severe anemia and liver and kidney injury. The detection rates of P. falciparum malaria were 98.33% (236/240), 95.42% (229/240), and 100% (240/240) in 240 anticoagulant blood samples from P. falciparum cases by rapid diagnostic tests (RDTs), microscopy, and quantitative Real-time PCR assay, respectively (χ² = 12.664, P < 0.05). P. falciparum was identified in peripheral blood smears from 240 P. falciparum malaria cases, with ring-stage alone seen in 70.42% (169/240) of blood smears, rings and trophozoites seen in 20.83% (50/240), and parasites at all developmental stages (rings, trophozoites, schizonts and gametocytes) in 5.00% (12/240). There were 34.17% (82/240) of cases with parasitemias ranging from 1/μL to 100 000/μL, and 21.25% (51/240) with parasitemias of > 250 000/μL. Multivariate logistic regression analysis identified parasitemia was an independent risk factor for severe malaria (OR > 1, P < 0.05). Conclusion A large number of P. falciparum malaria cases with widespread distributions were reported in Hubei Province from 2020 to 2024, and most cases acquired infections in Africa. Fever was the major clinical symptom. Some cases experienced a prolonged duration for a definitive diagnosis, and the proportion of severe case was high among imported P. falciparum malaria cases. Future efforts should focus on improving patients’ awareness of seeking healthcare services, shortening the duration to definitive diagnosis, providing timely and standardized treatment, in order to reduce the development of severe and fatal cases.

Key words: Plasmodium falciparum malaria, Epidemiological characteristic, Laboratory diagnosis, Severe case

CLC Number:

R531.32

YI Jia, LIN Wen, WU Dongni, DONG Xiaorong, SUN Lingcong, ZHU Hong, ZHANG Cong, TU Zhen, XIA Jing. Epidemiological characteristics and laboratory testing of Plasmodium falciparum malaria in Hubei Province from 2020 to 2024[J]. CHINESE JOURNAL OF PARASITOLOGY AND PARASITIC DISEASES, 2026, 44(2): 271-276.

Figures/Tables 5

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时间间隔/d Time interval/d	发病至初诊 Disease onset to initial diagnosis		初诊至确诊 Initial diagnosis to definitive diagnosis
时间间隔/d Time interval/d	病例数 No. case	构成比/% Proportion/%	病例数 No. case	构成比/% Proportion/%
≤ 1	136	54.18	165	65.74
2~3	69	27.49	57	22.71
4~5	29	11.55	14	5.58
> 5	17	6.77	15	5.98
合计 Total	251	100	251	100

初诊单位 Institutions for initial diagnosis	就诊病例数 No. cases seeking healthcare services	构成比/% Proportion/%	初诊确诊为疟疾病例数 No. cases definitively diagnosed as malaria at initial diagnosis	确诊率/% Rate of definitive diagnosis/%
省级医疗机构 Provincial-level medical institutions	26	10.36	19	73.08
地市级医疗机构 Prefectural-level medical institutions	102	40.64	91	89.22
县级医疗机构 County-level medical institutions	80	31.87	65	81.25
县级疾控机构 County-level CDC institutions	3	1.2	3	3/3
乡镇卫生院 Township health centers	14	5.58	6	6/14
村卫生室 Village clinics	13	5.18	1	1/13
个体医生 Private practitioners	8	3.19	1	1/8
其他 Others	5	1.99	2	2/5
合计 Total	251	100	188	74.9

发育期 Developmental stage	份数 No. case	占比/% Proportion/%	密度/个▪μl^-1 Parasite density/No. ▪μl^-1	份数 No. case	占比/% Proportion/%
环状体 Ring form	169	70.42	≤ 1 000	31	12.92
环状体、滋养体 Ring form, trophozoite	50	20.83	> 1 000~10 000	29	12.08
环状体、配子体 Ring form, gametocyte	6	2.50	> 10 000~100 000	82	34.17
各期均可见 All stages	12	5.00	> 100 000~250 000	47	19.58
配子体 Gametocyte	3	1.25	> 250 000	51	21.25
合计 Total	240	100	合计Total	240	100

指标 Index	回归系数 β Regression coefficient β	标准误 SE	Wald χ² 值 Wald χ² value	P值 P value	OR 值 OR value	OR置信区间 95%CI
初诊即明确诊断为疟疾 Definitive diagnosis as malaria at initial diagnosis	-0.289	0.672	0.185	> 0.05	0.749	0.201~2.797
境外居留期间是否采取预防措施 Whether preventive measures were taken during overseas residence	-0.948	0.514	3.404	> 0.05	0.387	0.141~1.061
是否有疟疾既往史 History of previous malaria infection	-0.187	0.475	0.155	> 0.05	0.829	0.327~2.103
是否转诊 Whether referred	0.778	0.616	1.596	> 0.05	2.177	0.651~7.281
初诊到确诊时间间隔 Days from initial diagnosis to definitive diagnosis	0.002	0.154	0	> 0.05	1.002	0.741~1.355
发病到确诊时间间隔 Days from onset to definitive diagnosis	0.137	0.089	2.398	> 0.05	1.147	0.964~1.365
疟原虫密度 Plasmodium density	0.963	0.333	8.357	< 0.05	2.619	1.364~5.032