Competent Authority: Health Commission of Anhui Province
Sponsor: Anhui Provincial Institute of Parasitic Diseases
Publishing: Editorial office of Tropical Dieases and Parasitology
Established in 1972
Editor-in-Chief: WANG Tianping
Executive Deputy Editor-in-Chief: CAO Zhiguo
Managing Editor: ZHANG Guangming
CSSN: ISSN 1672-2302 CN 34-1263/R
20 December 2024, Volume 22 Issue 6 Previous Issue   
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EXPERT FORUM
Research progress on the species, distribution and pathogens carried of Haemaphysalis
DU Chaobo, SUN Yi, JIANG Jiafu, DU Chunhong
2024, 22 (6):  321-327.  doi: 10.20199/j.issn.1672-2302.2024.06.001
Abstract ( 58 )   HTML ( 6 )   PDF (1070KB) ( 79 )  

Ticks are obligatory blood-sucking ectoparasites and vectors of a variety of pathogens. As the second largest genus of the Ixodidae, Haemaphysalis is of great public health significance and attracts much attention from the academic community because it holds the characteristics of diverse species, wide distribution and potentially carrying multiple pathogens. This review focuses on the research progress of the species, distribution and pathogen carriers of Haemaphysalis at home and abroad in recent years, so as to provide references for the prevention and control of Haemaphysalis-borne diseases.

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SPECIAL TOPICS ON VECTOR CONTROL
Study on the virus diversity of the mosquitoes carrying Japanese encephalitis virus
YAN Wenzhe, LI Jinyu, LUN Xinchang, LIU Pengbo, SONG Xiuping, GUO Yuhong, LIU Xiaobo, YUE Yujuan, LU Liang, ZHAO Ning
2024, 22 (6):  328-333.  doi: 10.20199/j.issn.1672-2302.2024.06.002
Abstract ( 58 )   HTML ( 4 )   PDF (2645KB) ( 18 )  

Objective To investigate the virome characteristics of the mosquitoes carrying Japanese encephalitis virus (JEV) for evidence in estimating the public health risks arising from mosquito-borne viruses. Methods According to the National Surveillance Program for Vector Pathogens (Trial), the infected mosquito samples carrying JEV were collected in the National Surveillance System for Mosquito-borne Pathogens from June to September 2022, and the data were further verified. Then the JEV positive mosquito samples with high nucleic acid quality from different provinces and distinct mosquito species were selected to undergo virome sequencing and bioinformatics analysis. The viral sequences were aligned and assembled, and phylogenetic analysis was performed in the important arboviruses that were annotated. Results In this study, a total of 8 pools with JEV-positive mosquitoes were investigated from 6 provinces, including Guizhou, Hubei, Jiangsu, Chongqing, Gansu and Yunnan. The mosquito species consisted of Anopheles sinensis, Culex quinquefasciatus and Culex tritaeniorhynchus. The results of virome sequencing showed that a total of 41 virus families and 118 known viruses were annotated. Among them, the abundance of Rhabdoviridae was relatively higher in more than half of the sampling sites. Twenty-two virus families were annotated in all 3 mosquito species. Quang Binh virus (QBV) was annotated in the mosquitoes sampled from 6 pools, and six near-full-length QBV sequences were obtained by assembly. Banna virus (BAV) was annotated in the specimens obtained from two pools, and two segments at the 12th of BAV were obtained by assembly. Two pools were annotated to Kadipiro virus (KDV), and the segment 1st sequence of KDV was obtained by assembly. Phylogenetic analysis showed that most of the QBV, BAV and KDV strains in this study were closely related to the strains isolated in China in recent years, and both BAV strains belonged to genotype A1. Conclusion This study enriched the understanding of mosquito viromes in China, and revealed the diversity of viruses in mosquitoes and the public health risks of arboviruses such as QBV, BAV and KDV. Thus, our findings may be important evidences in assessment of the risks and control of mosquito-borne infectious diseases in scientific fashion.

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Metagenomic analysis of symbiotic microbiota in Aedes albopictus from Songjiang District, Shanghai Municipality
YE Duqiu, ZHANG Chi, PANG Bowen, WU Jialing, JIANG Lufang, LÜ Xihong
2024, 22 (6):  334-338.  doi: 10.20199/j.issn.1672-2302.2024.06.003
Abstract ( 50 )   HTML ( 2 )   PDF (2734KB) ( 16 )  

ObjectiveTo preliminarily investigate the species diversity and functional variations of the symbiotic microflora in Aedes albopictus within the field environment of Songjiang District, Shanghai Municipality for understanding the changes of disease spectrum transmitted by Ae. albopictus and providing new ideas for biological control of Ae. albopictus. Methods Between July and September 2023, we harvested the Ae. albopictus samples by human trap method from the three field sampling sites in Guangfulin Country Park, Sheshan National Forest Park and Chenshan area, Songjiang District, Shanghai. After morphological identification of the specimens, DNA was extracted, and metagenomic sequencing technology was used to annotate the sample species. Functional annotation was performed through the Comprehensive Antibiotic Resistance Database (CARD) and Carbohydrate-Active enZymes Database (CAZy). Results In this investigation, we successfully captured 417 heads of Ae. albopictus in total, and annotated 236 bacterial genera and 23 viral genera, of which 52.97% (125/236) of the bacterial genera and 21.73% (5/23) of the viral genera were shared in the Ae. albopictus from 3 sampling sites. The dominant phyla of the symbiotic microbiota were Pseudomonadota and Bacillota, with Wolbachia, Streptococcus and Enterobacter showing the higher abundance. Exclusion of the unclassifiable microbial virus phylum, the prevailing virus phyla in the sampls consisted of Negarnaviricota and Peploviricota. Genera with relatively higher abundance included Alphanudivirus and Orthoflavivirus. Annotating the antibiotic resistance genes via CARD database showed that the abundance of fabG, abcA, rpoB and other pathways were higher. Annotation of the function of carbohydrate active enzymes based on CAZy database revealed higher abundance of glycosyl transferases (GT), glycoside hydrolases (GH) and polysaccharide lyases (PL). Conclusion The composition of symbiotic microbiota in Ae. albopictus in Songjiang District of Shanghai is highly similar and the core symbiotic microbiota remains stable. The symbiotic microbiota of Ae. albopictus is potentially associated with the drug resistance.

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Molecular epidemiological investigation of Bartonella infection in small mammals in Xishuangbanna Prefecture, Yunnan Province
LUO Zhi, YANG Hongmei, LI Dongmei, LI Miao, DU Chaobo, XIANG Rong, CAO Zhanxing, DU Chunhong
2024, 22 (6):  339-345.  doi: 10.20199/j.issn.1672-2302.2024.06.004
Abstract ( 51 )   HTML ( 4 )   PDF (2180KB) ( 22 )  

Objective To understand the status of Bartonella infection in small mammals living in Xishuangbanna Dai Autonomous Prefecture (referred to as Xishuangbanna Prefecture), Yunnan Province, for scientific evidences in local prevention and control of Bartonellosis. Methods Between 2021 and 2023, we captured small mammals in different environments in Menghai County, Mengla County, and Jinghong City of Xishuangbanna Prefecture, Yunnan Province. After morphological identification, the hearts, lives, spleens, and lungs were obtained, in which DNA was extracted to undergo amplification of the gltA gene fragment of Bartonella using PCR. Then the sequences of the positive PCR products were subsequently determined, and the homology and phylogenetic analysis were performed in the sequences obtained. Results A total of 219 small mammals representing 17 species were captured, including 193 rodents in 6 genera and 11 species, and 26 insectivores in 4 genera and 6 species. Among the captured small mammals, Rattus flavipectus was the most common (65.75%, 144/219), followed by Eothenomys eleusis (6.39%, 14/219), Mus pahari (4.57%, 10/219) and Crocidura dracula (4.57%, 10/219). A total of 29 small mammals were found to carry the target gene fragment, with a Bartonella infection rate of 13.24% (29/219). The infection rate was 14.58% (21/144), 7.14% (1/14), 40.00% (4/10), 22.22% (2/9) and 25.00% (1/4), respectively for Rattus flavipectus, Eothenomys eleusis, Mus pahari, Mus caroli and Niviventer fulvescens. By sequence alignment and analysis, 8 species of Bartonella were identified, in which 14 strains were associated with B. tribocorum, 7 strains with B. Queenslandensis, 2 strains with B. phoceensis, 2 strains with B. elizabethae, 1 strain with B. Kosoyi, 1 strain with B. Taylorii, 1 strain with B. Rochalimae, and 1 strain with B. sylvatica. Conclusion Bartonella infections are found in the small mammals living in the areas of Xishuangbanna Prefecture, Yunnan Province, and are characterized by diverse genotypes and hosts.

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Impact of RNA interference of acetylcholinesterase gene on the growth and survival of Pomacea canaliculata
ZHANG Jian, KAI Zhenpeng, CHENG Donghui, GUO Yunhai, ZHANG Yi
2024, 22 (6):  346-352.  doi: 10.20199/j.issn.1672-2302.2024.06.005
Abstract ( 43 )   HTML ( 3 )   PDF (2380KB) ( 13 )  

Objective To investigate the impact of RNA interference (RNAi) on the expression of the acetylcholinesterase (AChE) gene in Pomacea canaliculata and its effects on the growth and survival of the snail for potential application of RNAi technology in the control of this pest. Methods Double-stranded RNA (dsRNA) targeting the AChE gene of P. canaliculata was designed, and the corresponding plasmid was constructed and transformed into Escherichia coli to create engineered bacteria. The study included a blank control group, a negative control group, and experimental groups (F1, F2, F3, F4), with 10 snails in each group. The blank control group received no treatment, the negative control group was fed with E. coli carrying an empty vector, and the experimental groups F1, F2, F3, and F4 were fed with the engineered E. coli to express different AChE-dsRNAs. Real-time quantitative PCR (RT-qPCR) was used to detect the expression levels of AChE at 8, 12, and 24 hours post-treatment. The group showing the most significant change in AChE expression was selected for further feeding and injection tests to observe the survival and mortality of the snails. Results After feeding the snails with E. coli expressing AChE-dsRNA for 8 and 12 hours, group F2 showed a significant decrease in AChE expression (t=5.790, 10.110, P<0.01) compared to the negative control group, whereas groups F1, F3, and F4 did not show significant changes. After 24 hours of feeding, AChE expression was unaffected in the snails in each experimental group. Further feeding with E. coli expressing AChE-dsRNA-F2 for 30 days, the average weight of the snails in group F2 was increased by 16.9% [ranging from (0.560 9 ± 0.113 6) g to (0.655 9 ± 0.177 3) g], and the average weight of the snails in the negative control group was increased by 23.3%[ranging from (0.565 0 ± 0.131 7) g to (0.691 2 ± 0.156 8) g]. The difference in weight gain was statistically significant in both groups (F=2.720, P<0.05). Injection with E. coli expressing AChE-dsRNA-F2 led to a 30.0% mortality of the snails, compared to 13.3% in the control group, with significant difference between groups (χ2=4.910, P<0.05). Conclusion Feeding E. coli engineered to express AChE-dsRNA can effectively reduce the expression of the AChE gene in P. canaliculata and inhibit its weight gain, and injection with AChE-dsRNA-expressing E. coli may increase the mortality. Our findings suggest that RNAi technology may be a novel rationale in the control of P. canaliculata.

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CONTROL STUDY
Analysis of the reported incidence of notifiable diseases in Jilin Province from 2017 to 2023
ZHU Hong, ZHAO Qinglong, XU Changxi, PAN Yang, ZHU Linying, WU Hao, LI Meina
2024, 22 (6):  353-357.  doi: 10.20199/j.issn.1672-2302.2024.06.006
Abstract ( 39 )   HTML ( 2 )   PDF (2864KB) ( 10 )  

Objective To analyze the reported incidence of notifiable diseases in Jilin Province before and after the epidemic of COVID-19 for references to scientifically planning the monitoring, early warning, prevention and control of the infectious diseases. Methods The data on notifiable diseases reported in Jilin Province from 2017 to 2023 were retrieved from the China Information System for Disease Control and Prevention. Descriptive epidemiological methods were used to analyze the reported incidence of these notifiable diseases. Additionally, a comparative analysis was conducted to examine the incidence rates for the periods of 2017-2019, 2020-2022, and 2023. Results The reported incidence rate of notifiable diseases in Jilin Province from 2017 to 2023 ranged from 101.23/100 000 to 464.02/100 000, with an annual average reported incidence rate being 215.55/100 000. The overall trend showed a decrease followed by an increase, with the lowest reported incidence rate in 2020 and the highest in 2023. Before March 2022, the monthly reported incidence rates were generally stable. However, in March 2022, there was a rapid increase from 10.06/100 000 to a peak of 145.81/100 000, followed by a quick drop to 6.98/100 000 in May. In 2023, the monthly reported incidence rate remained at a high level throughout the year. The reported incidence rates of respiratory and intestinal infectious diseases were significantly influenced by the weighed COVID-19 prevention and control. From 2020 to 2022, the annual average reported incidence rates of respiratory infectious diseases (excluding COVID-19 cases) and intestinal infectious diseases was decreased by 43.45% and 71.76%, respectively, compared to the corresponding period from 2017 to 2019. In 2023, these rates were increased by 263.44% and 397.42%, respectively, compared to those in 2020-2022, and by 105.54% and 40.47%, respectively, compared to those in 2017-2019. The reported incidence rates of blood-borne and sexually transmitted diseases, as well as naturally occurring zoonotic diseases, remained generally stable. Among the 13 key preventable and controllable notifiable diseases, including influenza, pertussis, measles, etc., the reported incidence rate of pertussis had generally shown an upward trend, whereas the annual average reported incidence rates of the remaining 12 diseases from 2020 to 2022 tended to decrease to varying degrees compared to the incidences reported from 2017 to 2019. Conclusion The weighed prevention and control for COVID-19 epidemic had produced impact on the incidence of other notifiable diseases, especially on respiratory infectious diseases and intestinal infectious diseases.

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EXPERIMENTAL STUDY
Establishment and efficacy evaluation of a deep learning-based intelligent interpretation model for IHA detection results of Schistosoma japonicum antibody
MA Xiaohe, ZHANG Lesheng, WANG Fengfeng, LU Biao, SUN Chengsong, LI Qingyue, WANG Qi, CAO Zhiguo, WANG Tianping
2024, 22 (6):  358-363.  doi: 10.20199/j.issn.1672-2302.2024.06.007
Abstract ( 67 )   HTML ( 3 )   PDF (1523KB) ( 41 )  

Objective To develop an intelligent interpretation model for the results of indirect hemagglutination assay(IHA)of Schistosoma japonicum antibody in sera based on deep learning algorithms, and to preliminarily evaluate its efficacy so as to realize automatically and intelligently translating the results of schistosomiasis by diagnostic IHA. Methods Prepare and collect serum samples from rabbits (humans) with positive and negative results of Schistosoma japonicum, create IHA test result images with different levels of agglutination, and evaluate the agglutination results. The images with microtiter tray absent of IHA reaction were collected, and treated by enhancement, on which basis the image data sets were constituted. Then the intelligent interpretation model was created based on convolutional neural network PP-LCNet algorithms, and trained and tested respectively by training set and test set. The S. japonicum antibody gold-standard negative and positive rabbit sera diluted in different ratio (1∶5-1∶100) were detected by IHA, and the results were interpreted by three well-experienced professionals and the intelligent translating model independently. The performances of the model and professionals were evaluated as the specificity, sensitivity, accuracy, F1 score, diagnostic consistency (Kappa value). The receiver operation characteristic (ROC) curves were plotted to compare the coherence by the model and the professionals. Results In total, 15 956 images quantified by IHA were obtained, in which 2 271 were positive, 2 164 weak positive and 5 878 were negative reactions. Reaction was absent in 5 643 images of the microtiter trays. After the image enhancement, a total of 31 856 image sets were obtained, and divided training set (n=25 487) and test set (n=6 369). Efficacy evaluation showed that, except for the consistency in specificity (The agreement was 100.00% by the model and experts), the accuracy, sensitivity, F1 scores, Youden index and areas under ROC curves were 99.43%, 99.09%(97.84%, 100.34%), 99.54%, 0.990 9 and 0.995±0.009, respectively by the model results, which were slightly higher than the findings by professionals. The sensitivity of the intelligent interpretation model showed a statistically significant difference (χ2=6.125, 11.077, both P<0.05) between professional technicians A [95.45% (92.70%, 98.20%)] and B [93.18% (89.85%, 96.51%)], while there was no statistically significant difference (χ2=0.000, P>0.05) between professional technicians C [98.64% (95.31%, 97.17%)]. The results generated by the intelligent interpretation model highly agreed with gold standard. The consistency was somewhat better than the three professionals (Kappa= 0.988 vs. Kappa= 0.940, 0.910, 0.982, respectively, all P<0.05). Conclusion The intelligent interpretation model based on deep learning technology established in this study can accurately identify the results of S. japonicum antibody detection in sera by IHA, suggesting that it can be used for intelligently translating the IHA results for schistosomiasis japonica.

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INVESTIGATION STUDIES
First detection of Angiostronylus cantonensis infection in Pomacea canaliculata in Ma’anshan City
FAN Zehan, ZHAN Ti, SUN Chengsong, XIANG Kexia, JIANG Xiaoyu, WANG Weichun, DUAN Yongmei, ZHU Yingfu
2024, 22 (6):  364-366.  doi: 10.20199/j.issn.1672-2302.2024.06.008
Abstract ( 64 )   HTML ( 3 )   PDF (1099KB) ( 29 )  

Objective To investigate the distribution of Pomacea canaliculata and its status infected with Angiostronylus cantonensis in Ma’anshan City for evidences to plan the local prevention and control measures in scientific basis. Methods Between September and November 2023, we selected five townships (sub-districts) from each of the six counties (districts) in Ma’anshan area based on the geographical locations, and conducted field investigation to identify the presence of areas with Pomacea canaliculata. The snails were then collected from the breeding sites using netting methods, and their infection status was examined through microscopical inspection. The samples with suspected larvae at stage Ⅲ were subjected to molecular biological identification of Angiostrongylus cantonensis. Results In total, 30 townships (sub-districts) were investigated, in which Pomacea canaliculata were found in 12 townships (sub-districts), distributed in Huashan District, Yushan District, Dangtu County, Hexian County and Hanshan County. Nineteen breeding sites of Pomacea canaliculata were found in various environments including ditches, ponds, rivers, and lakes. A total of 452 Pomacea canaliculata were collected, in which 9 pieces of Angiostrongylus cantonensis larvae were detected from the samples obtained in Jinzitang Park located in Yangjiashan Community, Jinjiazhuang Sub-district, Huashan District (1 larva) and in a freshwater crab pond located in Xihu Community in Huyang Town, Dangtu County (8 larvae). Morphological observation and molecular biological identification confirmed that the larvae were Angiostrongylus cantonensis at stage Ⅲ. Conclusion Pomacea canaliculata were found to be present in Ma’anshan area, including Huashan District, Yushan District, Dangtu County, Hexian County and Hanshan County, and the snails infected with Angiostrongylus cantonensis were detected in the samples from Huashan District and Dangty County. This is the first discovery of the Pomacea canaliculata infected with Angiostronylus cantonensis in Ma’anshan area.

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Investigation and analysis of a cluster outbreak of visceral leishmaniasis in Xinjiang Uygur Autonomous Region
SHI Guangzhong, ADILI Simayi, ZHAO Jiangshan, MAIMAITIJIANG Umar, YUSUPJIANG Rosuli, LIU Huihui
2024, 22 (6):  367-370.  doi: 10.20199/j.issn.1672-2302.2024.06.009
Abstract ( 37 )   HTML ( 3 )   PDF (528KB) ( 22 )  

Objective To ascertain the causes of the outbreak via investigation and management of a clustered outbreak of visceral leishmaniasis in Akto County, Xinjiang Uygur Autonomous Region, for scientific basis in formulating more effective prevention and control measures for similar infections. Methods B-mode ultrasound and rK39 immunochromatographic test strips were used to screen key populations from May 28th to June 10th, 2022, and field study was conducted to investigate the potential transmission vectors in the affected area. Descriptive epidemiology was used to analyze the results investigate. Results The index case was a 1-year-and-4-month-old girl living at home in Village D, Township X, Akto County. She had no history of travel before infection. She first developed a fever on February 10, 2022, and was diagnosed with visceral leishmaniasis on May 8th. She was cured and discharged from the hospital on June 3rd. A total of 375 individuals were screened, and 1 clinically diagnosed case and 6 asymptomatic infections were identified, all of whom were local residents in Village D, Township X, Akto County. The first clinically diagnosed case developed symptoms in early September 2021 and reported no travel history within the year prior to onset, but had a history of mosquito bites. There were 4 males and 3 females, with ages ranging from 9 to 55 years old, including 3 individuals aged 10 or younger and 4 older than 10. By occupational distribution, three were students and four farmers. All cases or asymptomatic infections had a history of sandfly bites. A vector survey was conducted on June 1-2, 2022, during which three Phlebotomus longiductus Parrots were captured. Conclusion This endemic is a local clustered outbreak of visceral leishmaniasis, with the possible transmission vector being Phlebotomus longiductus Parrot. During the investigation and response period, spraying was carried out to eliminate sandflies in all residential houses, animal pens, and courtyards in the areas where confirmed and clinically diagnosed cases were located. The transmission was eventually and effectively controlled.

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TEACHING EXPLORATION
Exploration and application of Three-stages & Five-steps teaching method in the teaching reform of medical parasitology for the international students in China
ZHANG Ke, WU Jiahong, LUO Yusi
2024, 22 (6):  371-374.  doi: 10.20199/j.issn.1672-2302.2024.06.010
Abstract ( 35 )   HTML ( 2 )   PDF (949KB) ( 9 )  

At present, the traditional teaching mode in medical parasitology is insufficient to satisfy the requirements in training of the foreign students in China. To this end, it is urgent to explore new methods to improve the teaching. In this regard, the teaching group of School of Basic Medicine of Guizhou Medical University introduced the Three-stages & Five-steps teaching method into the teaching reform of medical parasitology for international students. Taking the teaching of Plasmodium as an example, this study introduces the connotation and significance, specific teaching measures and teaching effects of the Three-stages & Five-steps teaching method, with an attempt to assess the feasibility and promotion value of this method in the teaching of medical parasitology for the international students.

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REVIEW
Genetic differentiation of Oncomelania hupehensis by microsatellite and mitochondrial molecular biotechnology
LI Chunying, CUI Xiao, DU Chunhong, WANG Hongqiong, YANG Zaogai, Wang Yunsong, SONG Jing, DONG Yi
2024, 22 (6):  375-381.  doi: 10.20199/j.issn.1672-2302.2024.06.011
Abstract ( 42 )   HTML ( 2 )   PDF (1012KB) ( 16 )  

Oncomelania hupensis is the sole intermediate host of Schistosoma japonicum. Its geographical distribution plays crucial roles in the transmission and prevalence of schistosomiasis. Therefore, investigation on the snail genetic differentiation is greatly significant for snail and schistosomiasis control. With rapid development of molecular biology, a variety of molecular markers and sequence determination techniques have been widely used in the study of genetic differentiation of O. hupensis, among which DNA molecular markers and mitochondrial DNA sequence determination techniques possess obvious superiority in the study of genetic differentiation of O. hupensis population. This paper reviews the genetic differentiation of O. hupensis by using microsatellite DNA markers and mitochondrial DNA sequencing techniques.

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