Problems Associated with the Diagnosis of Imported Malaria in Anhui Province, China

Establishing and applying an adaptive framework for imported malaria: a field practice in Anhui Province, China from 2012 to 2022

BACKGROUND

Anhui Province is currently facing an increase in imported malaria cases as a result of globalization and international travel. In response, Anhui Province has implemented a comprehensive adaptive framework to effectively address this threat.

METHODS

This study collected surveillance data from 2012 to 2022 in Anhui Province. Descriptive statistics were used to analyze the epidemiological characteristics of imported malaria cases. Additionally, multivariate logistic regression was employed to identify factors associated with severe malaria. Documents were reviewed to document the evolution of the adaptive framework designed to combat imported malaria. The effectiveness of the adaptive framework was evaluated based on the rates of timely medical visits, timely diagnosis, and species identification.

RESULTS

During the study period, a total of 1008 imported malaria cases were reported across 77 out of 105 counties in Anhui Province, representing a coverage of 73.33%. It was found that 10.52% of imported cases went undiagnosed for more than seven days after onset. The multivariate analysis revealed several potential risk factors for severe malaria, including increasing age (OR = 1.049, 95%CI:1.015-1.083), occupation (waitperson vs. worker, OR = 2.698, 95%CI:1.054-6.906), a longer time interval between onset and the initial medical visit (OR = 1.061, 95%CI:1.011-1.114), and misdiagnosis during the first medical visit (OR = 5.167, 95%CI:2.535-10.533). Following the implementation of the adaptive framework, the rates of timely medical visits, timely diagnosis, and species identification reached 100.00%, 78.57%, and 100.00%, respectively.

CONCLUSIONS

Anhui Province has successfully developed and implemented an adaptive framework for addressing imported malaria, focusing on robust surveillance, prompt diagnosis, and standardized treatment. The experiences gained from this initiative can serve as a valuable reference for other non-endemic areas.

Evaluation of performance for malaria diagnosis in health facilities by five provincial reference laboratories of China

Introduction

The provincial malaria diagnosis reference laboratories review and assess malaria cases diagnosed in health facilities for supporting the malaria elimination efforts and preventing re-transmission of imported malaria. The study aimed to evaluate the detection capability of malaria diagnosis in China from 2014 to 2021.

Methods

Data on malaria cases reported in the provincial-level administrative divisions (PLADs) of Anhui, Henan, Hubei, Guangxi, and Zhejiang from 2014 to 2021 were collected and analyzed.

Results

In total, 5,770 malaria cases were reported from 2014 to 2021, and 99.05% (5,715/5,770) were submitted to the provincial malaria diagnosis reference laboratories. The median time between malaria cases being reported and the samples being received by reference laboratories was 6 days (Interquartile range, IQR:3-12 days) from 2017 to 2021. Diagnosis of 5,680 samples in the laboratory were confirmed by provincial reference laboratories, including 3,970 cases of Plasmodium falciparum, 414 of P. vivax, 1,055 of P. ovale, 158 of P. malariae, 1 of P. knowlesi, and 82 of mixed infections. Plasmodium species of 5,141 confirmed cases were consistent with the initial diagnosis, with a species accuracy rate of 90.53% (5,141/5,679). The accuracy of P. falciparum diagnosis in health facilities was higher than that of non-falciparum species. The inconsistency between microscopy and nested polymerase chain reaction (nPCR) results of confirmatory diagnosis was mainly in malaria-positive versus malaria-negative cases, as well as in mixed versus single infection cases.

Conclusion

The provincial malaria diagnosis reference laboratories have played an important role in ensuring the accuracy and reliability of Plasmodium diagnosis in health facilities. However, the results of this study imply that capacity training for the identification of Plasmodium species in health facilities is warranted.

Profile and determinants of delayed care-seeking and diagnosis among patients with imported malaria: a retrospective study in China, 2014-2021

BACKGROUND

In areas where malaria has been eliminated, delayed care-seeking and diagnosis of imported malaria are constant threats. This study aimed to describe the profile and determinants of delayed care-seeking and diagnosis among patients with imported malaria in China.

METHODS

This retrospective study assessed surveillance data obtained from 2014 to 2021 in the Chinese provincial-level administrative divisions (PLADs) of Anhui, Henan, Hubei, and Zhejiang, and Guangxi. Epidemiological characteristics were analyzed using descriptive statistics. Furthermore, factors associated with delayed care-seeking and diagnosis among imported malaria cases were identified using multivariate logistic regression.

RESULTS

Overall, 11.81% and 30.08% of imported malaria cases had delays in seeking care and diagnosis, respectively. During the study period, there was a decreasing trend in the proportion of imported malaria cases with delayed care-seeking (χ² = 36.099, P < 0.001) and diagnosis (χ² = 11.395, P = 0.001). In multivariate analysis, independent risk factors associated with delayed care-seeking include PLADs (Guangxi as reference), consultations in high-level facilities for the first medical visit, infections with non-Plasmodium falciparum species, and older age. However, PLADs (Guangxi as reference), the purpose of traveling (labour as reference), and infections with non-P. falciparum species increased the risk of delayed diagnosis. Delayed care-seeking (adjusted odds ratio: 1.79, P = 0.001) and diagnosis (adjusted odds ratio: 1.62, P = 0.004) were risk factors for severe disease development.

CONCLUSIONS

Based on this study's findings, we strongly advocate for improved access to quality healthcare to reduce the rate of misdiagnosis at the first visit. Infections caused by non-P. falciparum species should be highlighted, and more sensitive and specific point-of-care detection methods for non-P. falciparum species should be developed and implemented. In addition, education programs should be enhanced to reach target populations at risk of malaria infection. All these factors may reduce delayed care-seeking and diagnosis of imported malaria.

Malaria Microscopy Competency in the Subnational Verification, China: Implications for Malaria Elimination and the Prevention of Malaria Reestablishment

INTRODUCTION

Qualified microscopy competency is a key indicator for certification of malaria elimination. To better prepare the country certification and identify the priorities that need improvement to prevent malaria reestablishment, microscopy competency at different levels were assessed in subnational verification of malaria elimination in China. Methodology. Microscopist representatives from centers for disease control and prevention (CDC)/institutes of parasitic diseases (IPD) and medical institutes for malaria diagnosis at the provincial and county levels in the subnational verification were analyzed. Specifically, five provincial microscopist representatives and ten county-level representatives were assessed in each of previously endemic provinces on qualitative identification (Plasmodium positive or negative) and Plasmodium species identification using standard slides from the National Malaria Diagnosis Reference Laboratory.

RESULTS

A total of 100 provincial-level representatives (60 from 42 CDCs/IPDs and 40 from 34 medical institutes) and 200 county-level representatives (61 from 41 CDCs and 139 from 118 medical institutes) were included. The qualitative accuracy was higher than 90% each (P = 0.137), but slides with low parasite density were easy to be misdiagnosed as negative. Furthermore, the accuracy of species identification was 80.0% and 83.6% in medical institutes and centers for disease control and prevention (CDCs) at the provincial level (P = 0.407) with relatively high misdiagnosis of P. vivax as P. ovale in the latter (16.2%) and 82.0% and 85.0% in medical institutes and CDCs at the county level (P = 0.330) for the identification of P. falciparum and non-P. falciparum with higher false-negative in medical institutions (P < 0.001).

CONCLUSIONS

In conclusion, competent microscopy in subnational verification supported the quality in eliminating malaria in China, while the accurate identification of malaria parasites, especially slides with low parasite density still need to be improved through continuous diagnostic platform construction, continuous technological innovation, and targeted training to prevent reestablishment of malaria transmission.

Surveillance and Response to Imported Malaria During the COVID-19 Epidemic - Anhui Province, China, 2019-2021

What is already known about this topic?

China was certified malaria-free on June 30, 2021. However, imported malaria continuously threatens the effort to prevent re-establishment of malaria in China.

What is added by this report?

Measures such as international travel restrictions, entry quarantine, and screening in fever clinics during the coronavirus disease 2019 (COVID-19) period were associated with a significant decrease of imported malaria cases in Anhui Province, a higher proportion of non-Plasmodium falciparum (non-P. falciparum) malaria reported infections, and a higher proportion of cases requiring medical attention at their initial visit.

What are the implications for public health practices?

It is necessary to be vigilant about imported malaria during the COVID-19 epidemic, especially for non-P. falciparum infections which are more difficult to detect, and to promote research, development, and introduction of more sensitive and specific point-of-care detection methods for non-P. falciparum species.

Misdiagnosis of Plasmodium vivax in a Case of Mixed Malaria, Lead to Wrong Anti-Cancer Chemotherapy, Splenectomy, and Partial Hepatectomy Due to Relapse: A Case Report

Malaria is a multilateral parasitic infection, which causes wonderful mortality and morbidity worldwide. It sometimes accompanied a quaint appearance. An Iranian 50-year-old man was admitted to Omid, hospital, a specialized cancer hospital in Isfahan, Iran. Because of a 15-year persisted anemia due to misdiagnose of vivax malaria led him to three courses of anticancer chemotherapy and splenectomy. His blood smears were sent to the Department of Parasitology, School of Medicine, Isfahan University of Medical Sciences, Iran. Our findings from his history, file documents, clinical signs and symptoms, and parasitological and molecular assessments revealed an interesting case, which is reported.

Laboratory diagnosis for malaria in the elimination phase in China: efforts and challenges

Malaria remains a global health challenge, although an increasing number of countries will enter pre-elimination and elimination stages. The prompt and precise diagnosis of symptomatic and asymptomatic carriers of Plasmodium parasites is the key aspect of malaria elimination. Since the launch of the China Malaria Elimination Action Plan in 2010, China has formulated clear goals for malaria diagnosis and has established a network of malaria diagnostic laboratories within medical and health institutions at all levels. Various external quality assessments were implemented, and a national malaria diagnosis reference laboratory network was established to strengthen the quality assurance in malaria diagnosis. Notably, no indigenous malaria cases have been reported since 2017, but the risk of re-establishment of malaria transmission cannot be ignored. This review summarizes the lessons about malaria diagnosis in the elimination phase, primarily including the establishments of laboratory networks and quality control in China, to better improve malaria diagnosis and maintain a malaria-free status. A reference is also provided for countries experiencing malaria elimination.

Evaluation of the combination of rapid diagnostic tests and microscopy for imported malaria surveillance in Anhui Province, China

BACKGROUND

In the Anhui Province, China, efforts to interrupt the local malaria transmission were successful, with no endemic cases reported since 2014. Contrastingly, imported malaria cases are still being reported, indicating a disease reintroduction risk after years of elimination. A good surveillance system is key for avoiding the risk, detecting imported cases and possible cases associated with local transmission early. Therefore, rapid diagnostic tests (RDTs) were combined with microscopy to strengthen malaria surveillance in the province. Herein, we aimed to evaluate the efficacy of this surveillance strategy.

METHODS

We conducted a retrospective study using malaria surveillance data from January 2016 to June 2020. Epidemiological characteristics and diagnostic information were analysed using descriptive and comparative statistics. The diagnostic performance of the combined toolbox (Wondfo RDTs plus microscopy) was evaluated based on its sensitivity, specificity, positive and negative predictive values, and Cohen's kappa coefficient, using real-time polymerase chain reaction as the gold standard.

RESULTS

The combined toolbox displayed a higher overall sensitivity for malaria cases than that of microscopy alone (93.74% vs 89.37%; p_adj <0.05), which could detect 94.65%, 88.16%, 95.00%, and 100.00% of Plasmodium falciparum, P. ovale, P. vivax, and P. malariae infections, respectively. In clinical practice, Wondfo RDTs ability to detect P. falciparum infections was better than that of microscopy (97.55% vs 89.67%, p_adj < 0.05). In contrast, microscopy displayed a higher specificity than that of Wondfo RDTs (81.82% vs 63.28%, p _adj <0.05). Moreover, the consistency between microscopy and the gold standard results was also better than that of RDTs (Kappa value:0.669 vs 0.596).

CONCLUSIONS

The combination of microscopy and RDTs is an effective strategy for malaria surveillance because it possibly detected more P. falciparum infections due to the introduction of RDTs. In contrast, microscopy is complementary to some limitations related to the use of RDTs in field practice. Thus, monitoring malaria cases in non-endemic areas may require employing more than one diagnostic tool in surveillance strategies. Moreover, further understanding of the advantages and disadvantages of different detection methods is necessary for applying optimum combinations in field settings.

Loop-mediated isothermal amplification (LAMP) assays targeting 18S ribosomal RNA genes for identifying P. vivax and P. ovale species and mitochondrial DNA for detecting the genus Plasmodium

Background

Loop-mediated isothermal amplification (LAMP) has been widely used to diagnose various infectious diseases. Malaria is a globally distributed infectious disease attributed to parasites in the genus Plasmodium. It is known that persons infected with Plasmodium vivax and P. ovale are prone to clinical relapse of symptomatic blood-stage infections. LAMP has not previously been specifically evaluated for its diagnostic performance in detecting P. ovale in an epidemiological study, and no commercial LAMP or rapid diagnostic test (RDT) kits are available for specifically diagnosing infections with P. ovale.

Methods

An assay was designed to target a portion of mitochondrial DNA (mtDNA) among Plasmodium spp., the five human Plasmodium species and two other assays were designed to target the nuclear 18S ribosomal DNA gene (18S rDNA) of either P. vivax or P. ovale for differentiating the two species. The sensitivity of the assays was compared to that of nested PCR using defined concentrations of plasmids containing the target sequences and using limiting dilutions prepared from clinical isolates derived from Chinese workers who had become infected in Africa or near the Chinese border with Myanmar.

Results

The results showed that 10² copies of the mitochondrial target or 10² and 10³ copies of 18S rDNA could be detected from Plasmodium spp., P. vivax and P. ovale, respectively. In 279 clinical samples, the malaria Pan mtDNA LAMP test performed well when compared with a nested PCR assay (95% confidence interval [CI] sensitivity 98.48–100%; specificity 90.75–100%). When diagnosing clinical cases of infection with P. vivax, the 18S rDNA assay demonstrated an even great sensitivity (95.85–100%) and specificity (98.1–100%). The same was true for clinical infections with P. ovale (sensitivity 90.76–99.96%; specificity 98.34–100%). Using plasmid-positive controls, the limits of detection of Malaria Pan, 18S rDNA P. vivax and 18S rDNA P. ovale LAMP were 100-, 100- and tenfold lower than those of PCR, respectively.

Conclusion

The novel LAMP assays can greatly aid the rapid, reliable and highly sensitive diagnosis of infections of Plasmodium spp. transmitted among people, including P. vivax and P. ovale, cases of which are most prone to clinical relapse.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-04764-9.