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China used to be overloaded by the heavy burden caused by parasitic diseases. However, through several decades of effort, the number of cases and the prevalence of parasitic diseases had declined dramatically nationwide (1-3). However, misdiagnosis of parasitic diseases was reported from occasionally, especially for imported cases or asymptomatic cases with light infections. To understand the gap in diagnostic capacity that exists for parasitic diseases, a nationwide competition was conducted in August 2019 by the National Health Commission (NHC) through a paper test and interpretation of slides containing parasite worms or eggs. Generally, technicians grasped the knowledge of parasitic disease well but their practical skills for slides interpretation were not satisfactory with an overall accuracy rate of 66.87%. As parasitological methods relying on interpreting slides were still the gold standard for diagnosing parasitic diseases, further capacity building for diagnosis, especially parasitological methods, should be strengthened to avoid misdiagnosis of patients and provide accurate data for policymaking.
In August 2019, a national competition for parasitic diseases was held by the NHC in Changchun City of Jilin Province. A total of 32 teams with 128 technicians attended the competition. Each team was composed of four professional staff members, with at least one being from hospitals and two from agencies below the provincial level. All participants were aged less than or equal to 45 years old. The competition consisted of 2 parts: 1) theoretical knowledge on the life cycle of common parasites, their etiology and diagnosis, and control and prevention strategies of several parasitic diseases were evaluated through a paper test composed of 50 questions featured as single-choice, multiple-choice, and true or false categories; and 2) the technical skills for interpretation of blood smear slides and Kato-Katz thick smear slides were examined. All slides and the reference answers were prepared by the National Institute of Parasitic Disease (NIPD) of China CDC.
All assessment activities were conducted in parallel in single blind manner. The original results of each participant were entered into a computer by Microsoft Excel (version 2013, Microsoft Corp, Redmond, USA) and descriptive statistics was conducted by SPSS software (version 20, IBM Corp, Armonk, USA) to describe the general information of participants. The accuracy rate was calculated as the number of questions answered accurately divided by the total number of questions, or the accumulated number of parasite species in slides interpreted accurately divided by the total number of referenced parasite species provided by NIPD. Chi-squared statistics were used to compare the values between or among subgroups. The level of statistical significance was defined as P<0.05.
In total, 128 participants from 30 provincial-level administrative divisions (PLADs), Xinjiang Production and Construction Corps, and Chinese General Administration of Customs attended the competition. Overall, 28.9% (37/128) of participants were male and 71.1% (91/128) were female. All participants were aged with a mean value of 32.43±4.95 years old. The majority of participants (96.1%, 123/128) were junior staff with primary or middle level professional titles, while the rest were senior staff. Among of them, 82 participants were working at agencies of public health while 46 participants were from hospitals.
In the theoretical knowledge assessment, the accuracy rate was 80.44% (5,148/6,400) for all participants but varied from 38.00% (19/50) to 98.00% (49/50). Chi-square analysis showed that the females had higher accuracy rates than the males (χ2=14.139, P<0.01) while the accuracy rate in participants from public health agencies was higher than that from hospitals (χ2=8.374, P<0.01). Significant differences were also detected when analyzing accuracy rates by strata of professional titles and agencies (χ2=8.571, χ2=24.023, P<0.05). But no difference in accuracy rate was found among different age groups (χ2=2.442, P>0.05) (Table 1).
Categories Features No. participants No. questions answered No. questions answered accurately Accuracy rate (%) Chi-square test Total 128 6,400 5,148 80.44 Gender Male 37 1,850 1,434 77.51 χ2=14.139, P<0.001 Female 91 4,550 3,714 81.63 Age, years ≤30 43 2,150 1,706 79.35 χ2=2.442, P=0.295 31–40 72 3,600 2,915 80.97 ≥41 13 650 527 81.08 Professional title Primary 74 3,700 2,933 79.27 χ2=8.571, P=0.014 Middle 49 2,450 2,004 81.80 High 5 250 211 84.40 Agency level Province 19 950 709 74.63 χ2=24.023, P<0.001 City 40 2,000 1,624 81.20 County 69 3,450 2,815 81.59 Agency feature Public health 82 4,100 3,342 81.51 χ2=8.374, P=0.004 Hospital 46 2,300 1,806 78.52 Table 1. The accuracy rates of 128 participants for knowledge test related to parasitic diseases in China, 2019.
For the knowledge points, the accuracy rates regarding to diagnosis, detection technology, the life cycle of parasites, and control and prevention of parasitic diseases were 84.90% (1,304/1,536), 84.01% (1,398/1,664), 83.52% (1,176/1,408), and 70.87% (1,270/1,792), respectively, presenting significant differences (χ2=145.682, P<0.05). In addition, the accuracy rates of answers to questions related to the diagnosis of schistosomiasis, malaria, echinococcosis, other parasitic disease, and comprehensive issues were 84.38% (1,080/1,280), 83.98% (1,075/1,280), 76.72% (982 /1,280), 81.75% (1,465/1,792), and 71.09% (546/768), respectively, showing significant difference (χ2=78.673, P<0.05).
For the interpretation of slides, the accuracy rate for thick smear slides and blood smear slides was 67.19% (2,097/3,121) and 65.31% (418/640), respectively, with the overall accuracy rate being 66.87% (2,515/3,761) (Table 2). Individually, the accuracy rate for the interpretation of thick smear slides ranged from 10% (3/30) to 96.55% (28/29); 22 participants had a 100% accuracy rate, but 4 participants provided all wrong answers for blood smear slides interpretation. The average accuracy rates did not differ significantly among agencies (χ2=5.494, χ2=0.073, P>0.05), but females, younger professional staff, and senior staff had higher accuracy rates (P<0.05).
Categories Features No. participants Accumulated slides number Accumulated slides number judged parasites correctly Accuracy rate (%) Chi-square test Total 128 3,761 2,515 66.87 Gender Male 37 1,082 688 63.59 χ2=7.397,
P=0.007Female 91 2,679 1,827 68.20 Age, years ≤30 43 1,268 896 70.66 χ2=12.655,
P=0.00231–40 72 2,114 1,377 65.14 ≥41 13 379 242 63.85 Professional title Primary 74 2,173 1,477 67.97 χ2=7.614,
P=0.020Middle 49 1,441 930 64.54 High 5 147 108 73.47 Agency level Province 19 559 351 62.79 χ2=5.494,
P=0.064City 40 1,171 801 68.40 County 69 2,031 1,363 67.11 Agency feature CDC 82 2,423 1,624 67.02 χ2=0.073,
P=0.787Hospital 46 1,338 891 66.59 Note: CDC: Center for Disease Control and Prevention. Table 2. The accuracy rates of participants for slides interpretation in China, 2019.
In analyzing the accuracy rates by helminth species, the highest accuracy was 87.50% (420/480) for the detection of Clonorchis sinensi, followed by 83.73% (669/799) for Ascarias spp. The lowest accuracy rate was 25.89% (124/479) for detection of Schistosoma japonicum (Table 3). Significant differences in accuracy rates were detected among helminth species identification (χ2=593.544, P<0.05). For identification of plasmodium species, the accuracy rate for detecting Plasmodium malariae, P. falciparum, P. vivax, and negative slides were 57.50% (23/40), 60.47% (179/296), 69.64% (117/168), and 72.79% (99/136), respectively, presenting significant differences (χ2=8.888, P<0.05). The accuracy rate of participants from schistosomiasis endemic areas for schistosomiasis slides interpretation was 35.87% (66/184), significantly higher than that of 19.66% (58/295) in participants from non-endemic areas (χ2=15.517, P<0.01). Similarly, the accuracy rate of participants from malaria endemic areas for malaria slides interpretation was higher than that of participants from non-endemic areas [70.00% (322/460) vs, 53.33% (96/180), χ2=15.863, P<0.01].
Types of slides Types of parasites in slides Accumulated number
of slidesAccumulated number of
slides judged correctlyAccuracy rate (%) Total 3,761 2,515 66.87 Thick smear slides Schistosoma japonicum 479 124 25.89 Trichuris trichiura 161 97 60.25 Paragonimus 320 206 64.38 Fasciolopsis 80 64 80.00 Ascarias spp. 799 669 83.73 Enterobius vermicularis 241 183 75.93 Clonorchis sinensis 480 420 87.50 Taeniidae 240 142 59.17 Spirometra mansonia 321 192 59.81 Subtotal 3,121 2,097 67.19 Blood smear slides Plasmodium falciparum 296 179 60.47 Plasmodium vivax 168 117 69.64 Plasmodium malariae 40 23 57.50 Negatives 136 99 72.79 Subtotal 640 418 65.31 Table 3. The accuracy rates of 128 participants for parasites identification based on slides interpretation in China, 2019.
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