Epidemiological survey of cystic echinococcosis in southwest China: From the Qinghai-Tibet plateau to the area of Yunnan.

BACKGROUND: Echinococcosis is prevalent in 9 provinces in Western and Northern China. An epidemiological survey of echinococcosis in 2012 and 2016 showed cases of echinococcosis in Yunnan Province. AIM: To understand the spatial distribution and epidemiological characteristics of echinococcosis in Yunnan for the prevention and control of echinococcosis and to reduce the risk of infection in Yunnan Province. METHODS: Based on the China Information System for Disease Control and Prevention (CISDCP), echinococcosis cases reported from 36 hospitals and 34 Centers for Disease Control were investigated and epidemiologically analyzed from 2021 to 2022. The exclusion criteria included suspected cases, same case only counted once and cases not from Yunnan. A total of 705 cases were investigated, of which 397 cases were suitable for statistical analysis. In these 397 cases, epidemiological investigation was tracked in 187 cases. All data were inputted using double entry in the Excel database, with error correction by double-entry comparison. The data on echinococcosis cases in Yunnan Province were analyzed by ArcGIS 10.1 software to generate a density map of echinococcosis distribution. All statistical analyses were conducted using SPSS 17.0, including the chi-square test, linear regression test and logistic univariate and multivariate regression analyses. RESULTS: A total of 397 cases were found in 89 counties in Yunnan Province. The number of cases in the top three prefectures were Dali (38.1%), Diqing (10.1%), and Kunming (8.3%), and the top five counties were Jianchuan (9.1%), Shangri La (8.3%), Eryuan (7. 6%), Heqing (6.9%), and Dali Districts (5.0%). There were significant differences between the different areas. The case reporting rate by CISDCP (33.8%) was low; the first case was reported by CISDCP in 2002, and the highest number of cases was 50 (2017). Confirmed and clinical cases accounted for 62.5% and 37.5%, respectively. However, 90.9% of the cases of hydatid disease were reported by the hospital system, and only 9.1% of the cases of hydatid disease were found in the community through active screening. The difference between the two methods of case detection was statistically significant. Most of the cases of echinococcosis were found in farmers/herdsmen (75.1%) and students (9.1%). In addition, Han (43.6%) and Bai (26.2%) had a higher incidence of infection than other nationalities, and the liver (87.7%) and lung (6.8%) were the most common sites of cyst formation. Among the analyzed cases, 187 were epidemiologically analyzed and the clinical symptoms were not obvious in the early stage in 47.1% of cases. The results of logistic regression analysis showed that the age group, education level, presence of dogs in the family (either previously or currently), and handwashing (occasionally or not) were factors related to echinococcosis infection. 55.6% of cases were in endemic areas, and 44.4% of cases were in non-endemic areas. Among 83 cases in non-endemic areas, only 4 cases had been to endemic areas and had a history of living, working, travelling, or hunting in echinococcosis epidemic areas. CONCLUSION: Cases of echinococcosis were reported throughout the entire Yunnan province, with the majority distributed in Western Yunnan, suggesting that echinococcosis control should be strengthened in this area. We suggest that an epidemiological investigation should be carried out in the future, based on the clues from newly discovered cases in hospitals or from the CISDCP. The newly discovered cases in the hospital provided clues to comprehensively determine the location of cases and where epidemic spot investigation should be conducted.

Genetic polymorphism of merozoite surface proteins 1 and 2 of Plasmodium falciparum in the China-Myanmar border region.

BACKGROUND: Malaria is a major public health problem in the China-Myanmar border region. The genetic structure of malaria parasite may affect its transmission model and control strategies. The present study was to analyse genetic diversity of Plasmodium falciparum by merozoite surface proteins 1 and 2 (MSP1 and MSP2) and to determine the multiplicity of infection in clinical isolates in the China-Myanmar border region. METHODS: Venous blood samples (172) and filter paper blood spots (70) of P. falciparum isolates were collected from the patients of the China-Myanmar border region from 2006 to 2011. The genomic DNA was extracted, and the msp1 and msp2 genes were genotyped by nested PCR using allele-specific primers for P. falciparum. RESULTS: A total of 215 P. falciparum clinical isolates were genotyped at the msp1 (201) and msp2 (204), respectively. For the msp1 gene, MAD20 family was dominant (53.49%), followed by the K1 family (44.65%), and the RO33 family (12.56%). For the msp2 gene, the most frequent allele was the FC27 family (80.93%), followed by the 3D7 family (75.81%). The total multiplicity of infection (MOI) of msp1 and msp2 was 1.76 and 2.21, with a prevalence of 64.19% and 72.09%, respectively. A significant positive correlation between the MOI and parasite density was found in the msp1 gene of P. falciparum. Sequence analysis revealed 38 different alleles of msp1 (14 K1, 23 MAD20, and 1 RO33) and 52 different alleles of msp2 (37 3D7 and 15 FC27). CONCLUSION: The present study showed the genetic polymorphisms with diverse allele types of msp1 and msp2 as well as the high MOI of P. falciparum clinical isolates in the China-Myanmar border region.

Exploring the relationship of peripheral total bilirubin, red blood cell, and hemoglobin with blood pressure during childhood and adolescence / Explorando a relação entre os níveis periféricos de bilirrubina total, glóbulos vermelhos e hemoglobina e a pressão arterial na infância e adolescência

Abstract Objective: Total bilirubin is beneficial for protecting cardiovascular diseases in adults. The authors aimed to investigate the association of total bilirubin, red blood cell, and hemoglobin levels with the prevalence of high blood pressure in children and adolescents. Methods: A total of 3776 students (aged from 6 to 16 years old) were examined using cluster sampling. Pre-high blood pressure and high blood pressure were respectively defined as the point of 90th and 95th percentiles based on the Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents. Both systolic and diastolic blood pressure were standardized into z-scores. Results: Peripheral total bilirubin, red blood cell and hemoglobin levels were significantly correlated with age, and also varied with gender. Peripheral total bilirubin was negatively correlated with systolic blood pressure in 6- and 9-year-old boys, whilst positively correlated with diastolic blood pressure in the 12-year-old boys and 13- to 15-year-old girls (p < 0.05). Higher levels of red blood cell and hemoglobin were observed in pre-high blood pressure and high blood pressure students when compared with their normotensive peers (p < 0.01). The increases in red blood cell and hemoglobin were significantly associated with high blood pressure after adjusting for confounding factors. The ORs (95% CI) of each of the increases were 2.44 (1.52-3.92) and 1.04 (1.03-1.06), respectively. No statistical association between total bilirubin and high blood pressure was observed (p > 0.05). Conclusion: Total bilirubin could be weakly correlated with both systolic and diastolic blood pressure, as correlations varied with age and gender in children and adolescents; in turn, the increased levels of red blood cell and hemoglobin are proposed to be positively associated with the prevalence of high blood pressure.

Resumo Objetivo: A bilirrubina total é benéfica para proteger contra doenças cardiovasculares em adultos. Nosso objetivo foi investigar a associação dos níveis de bilirrubina total, glóbulos vermelhos e hemoglobina com a prevalência de pressão arterial elevada em crianças e adolescentes. Métodos: Um total de 3.776 estudantes (com idade entre 6-16 anos) foram examinados utilizando uma amostra em blocos. A pressão arterial elevada anterior e a pressão arterial elevada foram definidas como o 90° e 95° percentil, respectivamente, com base nos critérios do Quarto Relatório sobre Diagnóstico, Avaliação e Tratamento da Pressão Arterial elevada em Crianças e Adolescentes. A pressão arterial sistólica e pressão arterial diastólica foram padronizadas no escore z. Resultados: Os níveis periféricos de bilirrubina total, glóbulos vermelhos e hemoglobina foram significativamente correlacionados à idade, que também variou de acordo com o sexo. A bilirrubina total periférica apresentou uma correlação negativa com a pressão arterial sistólica em meninos com 6 e 9 anos, ao passo que apresentou uma correlação positiva com a pressão arterial diastólica em meninos de 12 anos e meninas de 13 a 15 anos (p < 0,05). Foram observados níveis mais elevados de glóbulos vermelhos e hemoglobina em estudantes com pressão arterial elevada anterior e pressão arterial elevada em comparação a indivíduos normotensos (p < 0,01). Os aumentos de glóbulos vermelhos e hemoglobina tiveram uma associação significativa com a pressão arterial elevada após ajuste dos fatores de confusão. As RC (IC de 95%) de cada um dos aumentos foram 2,44 (1,52-3,92) e 1,04 (1,03-1,06) respectivamente. Não foi observada nenhuma associação estatística entre o nível de bilirrubina total e a pressão arterial elevada (p > 0,05). Conclusão: A bilirrubina total pode ter correlações fracas com a pressão arterial sistólica e a pressão arterial diastólica, variando de acordo com a idade e o sexo em crianças e adolescentes, enquanto isso, propõe-se que o aumento dos níveis de glóbulos vermelhos e hemoglobina está positivamente associado à prevalência de pressão arterial elevada.

Exploring the relationship of peripheral total bilirubin, red blood cell, and hemoglobin with blood pressure during childhood and adolescence.

OBJECTIVE: Total bilirubin is beneficial for protecting cardiovascular diseases in adults. The authors aimed to investigate the association of total bilirubin, red blood cell, and hemoglobin levels with the prevalence of high blood pressure in children and adolescents. METHODS: A total of 3776 students (aged from 6 to 16 years old) were examined using cluster sampling. Pre-high blood pressure and high blood pressure were respectively defined as the point of 90th and 95th percentiles based on the Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents. Both systolic and diastolic blood pressure were standardized into z-scores. RESULTS: Peripheral total bilirubin, red blood cell and hemoglobin levels were significantly correlated with age, and also varied with gender. Peripheral total bilirubin was negatively correlated with systolic blood pressure in 6- and 9-year-old boys, whilst positively correlated with diastolic blood pressure in the 12-year-old boys and 13- to 15-year-old girls (p<0.05). Higher levels of red blood cell and hemoglobin were observed in pre-high blood pressure and high blood pressure students when compared with their normotensive peers (p<0.01). The increases in red blood cell and hemoglobin were significantly associated with high blood pressure after adjusting for confounding factors. The ORs (95% CI) of each of the increases were 2.44 (1.52-3.92) and 1.04 (1.03-1.06), respectively. No statistical association between total bilirubin and high blood pressure was observed (p>0.05). CONCLUSION: Total bilirubin could be weakly correlated with both systolic and diastolic blood pressure, as correlations varied with age and gender in children and adolescents; in turn, the increased levels of red blood cell and hemoglobin are proposed to be positively associated with the prevalence of high blood pressure.

Assessment of malaria control consultation and service posts in Yunnan, P. R. China.

BACKGROUND: This paper seeks to assess the function of malaria control consultation and service posts (MCCSPs) that are located on the border areas of Yunnan province, P.R. China, as a strategy for eliminating malaria among the mobile and migrant population in these areas. METHODS: A retrospective descriptive analytical study was conducted. Blood smear examinations conducted at all MCCSPs in Yunnan from 2008 to 2014 were analysed. A cross-sectional survey was conducted in 2014 to understand how the MCCSPs function and to elucidate the quality of the blood smear examinations that they conduct. RESULTS: Out of the surveyed MCCSPs, 66 % (39/59), 22 % (13/59), and 12 % (7/59) were attached to local township hospitals, village health clinics, and the county centre for disease control and prevention or private clinics, respectively. More than 64 % (38/59) of the posts' staff were part-time workers from township hospitals and village health facilities. Less than 31 % (18/59) of the posts' staff were full-time workers. A total of 35 positive malaria cases were reported from seven MCCSPs in 2014. Four MCCSPs were unable to perform their functions due to under staffing in 2014. There was a small fluctuation in blood smear examinations from January 2008 to June 2009, with two peaks during the period from July 2009 to October 2010. The number of blood smear examinations has been increasing since 2011. The yearly mean number of blood smear examinations in each post increased from 44 per month in 2011 to 109 per month in 2014, and the number of positive malaria cases detected by blood smear examinations has declined (χ 2 = 90.67, P = 0.000). The percentage of people from Yingjiang county getting blood smear examinations increased between 2008 and 2014, while percentages of the mobile population including Myanmar people, people from other provinces, and people from other Yunnan counties getting blood smear examinations decreased. CONCLUSION: MCCSPs face challenges in the phase of malaria elimination in Yunnan, China. New case detection strategies should be designed for MCCSPs taking into account the current trends of migration.

Malaria control along China-Myanmar Border during 2007-2013: an integrated impact evaluation.

BACKGROUND: Implementing effective interventions remain a lot of difficulties along all border regions. The emergence of artemisinin resistance of Plasmodium falciparum strains in the Greater Mekong Subregion is a matter of great concern. China has effectively controlled cross-border transmission of malaria and artemisinin resistance of P. falciparum along the China-Myanmar border. METHODS: A combined quantitative and qualitative study was used to collect data, and then an integrated impact evaluation was conducted to malaria control along the China-Myanmar border during 2007-2013. RESULTS: The parasite prevalence rate (PPR) in the five special regions of Myanmar was decreased from 13.6 % in March 2008 to 1.5 % in November 2013. Compared with the baseline (PPR in March 2008), the risk ratio was only 0.11 [95 % confidence interval (CI), 0.09-0. 14) in November 2013, which is equal to an 89 % reduction in the malaria burden. Annual parasite incidence (API) across 19 Chinese border counties was reduced from 19.6 per 10 000 person-years in 2006 to 0.9 per 10 000 person-years in 2013. Compared with the baseline (API in 2006), the API rate ratio was only 0.05(95 % CI, 0.04-0.05) in 2013, which equates to a reduction of the malaria burden by 95.0 %. Meanwhile, the health service system was strengthened and health inequity of marginalized populations reduced along the international border. CONCLUSION: The effective collaboration between China, Myanmar and the international non-governmental organization promptly carried out the core interventions through simplified processes. The integrated approaches dramatically decreased malaria burden of Chinese-Myanmar border.

[Species Identification and Sequence Analysis of Plasmodium spp. in Border Areas of Yunnan Province by 18S rRNA-based Nested PCR]

Objective: To analyze blood samples from patients with falciparum malaria and vivax malaria in border areas of Yunnan Province, using 18S rRNA-based nested PCR, and compare 18S rRNA sequences. Methods: Blood or filter blood samples with positive microscopic results for Plasmodium falciparum or P. vivax infection were collected from Laza, Nankajiang, Mangdong and Nawei of Myanmar, and from Mengla, Tengchong and Yingjiang of Yunnan Province between 2004 and 2011. 18S rRNA-based nested PCR was conducted on the samples, and PCR products were sequenced and blasted. Phylogenetic tree was constructed using the neighbor-joining method with MEGA software (version 6.06). Results: Microscopic examination revealed P. falciparum infection in 256 samples and P. vivax infection in 219 samples. The 18S rRNA-based PCR further confirmed P. falciparum infection in 242 samples, P. vivax infection in 176 samples, and mixed infection in 57 samples. The consistency rate was 81.7% （388/475） between microscopic and PCR results. The inconsistency rate significantly correlated with parasite density （Spearman's r=-0.408， P<0.05）. Sequence alignment revealed 11 and 10 homologous sequences for P. falciparum and P. vivax 18S rRNA gene, comprising 2.9%（6/205） and 22.5%（27/120） variable sites, respectively. The 18S rRNA of P. falciparum clustered with that from Cameroon（GenBank accession number KC428742）, but was distantly related with the S-type 18S rRNA from the Netherlands （U36465） and Brazil （U36466 and U36467）. The 18S rRNA of P. vivax clustered with A-type 18S rRNA from Thailand （U07367）, but was distantly related with the C-type 18S rRNA from Thailand（U07368）. Conclusion: Nested PCR revealed mixed infection in 57 samples among those identified with single infection by microscopy. There is no significant difference in 18S rRNA sequence in seven counties/cities in Yunnan Province.

[Risk Assessment for Malaria Transmission in the Border Area of Yunnan Province].

Objective: To assess the malaria transmission risk in the border area of Yunnan Province and provide evidence for adjustment of malaria intervention and elimination strategies. Method: Data concerning malaria prevalence, vector distribution, and institutional intervention capacity were collected in 197 towns of 20 counties in the border area of Yunnan Province during 2012-2014. The malaria transmission potential index （TPI）, intervention capacity index (ICI) and malaria risk index (MRI) were calculated for each town, based on the criteria formulated by a professional committee. The towns were categorized according to the indices aforementioned. The risk map was created with GIS software. Results: Based on the TPI, the 197 towns comprised of 2 grade-I towns (including Nabang in Yingjiang and Banlao in Cangyuan) with high transmission potential, 11 grade-II towns with moderate transmission potential and 184 grade-III towns with low transmission potential. Based on the ICI, the 197 towns comprised of 4 grade-III towns (including Zhongke in Ximen, Zhonghe and Diantan in Tengchong, and Menghan in Jinghong) with a weak control capacity, 20 grade-II towns with a moderate control capacity and 173 grade-I towns with a strong control capacity. Based on the MRI, the 197 towns comprised of 2 grade-I towns (including Nabang in Yingjiang, and Banlao in Cangyuan) with a high transmission risk level, 12 grade-II towns with a moderate level and 183 grade-III towns with a low level distributed in 20 counties. Conclusion: The grade I or II towns with moderate and high transmission risk constitute <5% of the 197 towns in the border area, suggesting a relatively low level of malaria transmission risk in most counties.

[Evaluation on Malaria Hotspots in Yingjiang County of the China-Myanmar Border Area in 2015].

Objective: To understand the control status of malaria at hotspots in Yingjiang County and provide measures for malaria elimination in the China-Myanmar border areas of Yunnan Province. Methods: A survey was made in 4 villages with indigenous malaria cases or imported cases in Nabang and Tongbiguan of Yingjiang County in Yunnan Province in June and July 2015. Peripheral blood samples were collected from the neighboring residents around patients and examined by malaria rapid diagnostic test （RDT）. The results were further verified by nested-PCR. Mosquitoes were collected by overnight trapping with light traps in Jingpo, Lilisu, Jiema, and Mengxiangyang villages or by human landing catches in Jingpo and Lisu villages. Nested-PCR was performed on part of the captured Anopheles minimus to detect the malaria parasites. Results: One hundred and ninety-four filter blood samples were collected from 11 malaria cases in two sites. All were detected to be negative for Plasmodium by RDT. In contrast, two samples originated from Jingpo and Lisu villages with indigenous cases were detected to be positive for Plasmodium vivax by nested-PCR. A total of 2 374 mosquitoes were captured, belonging to 22 species of 4 genera: Anopheles, Culex, Aedes and Armigeres. The mosquitoes were predominated by genus Culex, followed by genus Anopheles（11.33%, 269/2 374） which was dominated by A. minimus（49.07%, 132/269）, then was A. sinensis（4.09%, 11/269）, A. maculatus（2.23%, 6/269）, A. jeyporiensis（0.74%, 2/269）and so on. The mean indoor man-biting rate of mosquitoes was 5.78 and 3.20 per person per hour for Jingpo and Lisu villages, and the mean outdoor man-biting rate of mosquitoes was 2.30 per person per hour for Lisu Village. The 14 A. minimus were negative for sporozoite infection as detected by nested-PCR. Conclusion: Nested-PCR showed that there are asymptomatic Plasmodium carriers in Yingjiang's border area of Yunnan Province. Four major mosquito species as malaria vectors exist with A. minimus as the dominant one.

[Primary evaluation on the application of nested/multiplex PCR in malaria diagnosis and surveillance].

OBJECTIVE: To compare the usefulness of Tag-primer nested/multiplex PCR (UT-PCR) method with microscopy in malaria diagnosis and surveillance. METHODS: 400 blood smears and blood samples on filter paper were taken from febrile patients which were initially diagnosed as malaria or suspected malaria during surveillance in mixed endemic areas of Plasmodium falciparum (Pf) and P. vivax (Pv) in Hainan and Yunnan provinces and a malaria-controlled area in Guangxi Zhuang Autonomous Region. The initial test results of both UT-PCR and microscopy for the 400 samples were compared under double blind condition. Blood smears with discrepant results between the two methods were retested by an experienced microscopist, and also repeated by UT-PCR for 2-3 times. The sensitivity and specificity of the two methods were evaluated following the Tjitra's method. RESULTS: Among the 400 blood samples, 234 were found plasmodium-positive by microscopy with 125 Pf and 109 Pv; 235 were positive by UT-PCR including 124 Pf, 109 Pv and 2 mixed infection. Altogether, the coincidence between the two methods stood for 92.5 % (370/400), including 154 negatives and 216 positives (Pv 117, Pf 99). 25 samples with discrepancy from the initial detections were retested, which covered 11 microscopy negative and PCR positive, 10 microscopy positive and PCR negative, 3 microscopy Pf positive and PCR Pv positive, 1 microscopy Pv positive but PCR mixed infection. 15 of the 25 samples showed same UT-PCR results, 7 "false positives" and 3 "false negatives" . Therefore, the sensitivity and specificity of UT-PCR was 99.6% and 98.8% respectively. CONCLUSION: As a diagnosis method, UT-PCR is useful for confirmation of malaria diagnosis and differentiation of Plasmodium species, also for improving the effectiveness and quality of malaria surveillance.

Assessment of therapeutic efficacy of chloroquine against falciparum malaria in an outbreak area in Xishuangbanna, Yunnan.

OBJECTIVE: To investigate the failure of treatment with chloroquine in Yunnan in order to help formulate adequate antimalarial drug policy. METHODS: A World Health Organization 28-day in vivo test on therapeutic response for uncomplicated falciparum malaria in area with low or moderate transmission was adopted. Patients of age > or = 6 months old were admitted without limitation in density of parasitaemia and body temperature. Clinical and parasitological observation was conducted for patients on day 0, 1, 2, 3, 4, 7, 14, 21, 28 and 35. RESULTS: Of 62 patients identified as malaria cases infected by Plasmodium falciparum only, Plasmodium vivax only or by both species, 52 cases infected by Plasmodium falciparum only were included in the study. The overall treatment failure rate was 40.7%, with early treatment failure (ETF) rate of 1.8% and late treatment failure rate (LTF) of 38.9%. CONCLUSION: The treatment failure rate was much higher than the rate of 25% recommended by WHO. It is suggested that use of single chloroquine should be stopped in the treatment of falciparum malaria cases in such area. No relationship was found between the failure rate and the density of malaria parasites.