Search

In 2010, China issued the National Malaria Elimination Action Plan (2010-2020), with the goal of eliminating malaria nationwide by 2020 (1). Malaria cases in China subsequently decreased dramatically, and no [...]

Chikungunya fever is an acute infectious disease caused by the chikungunya virus (CHIKV) that is characterized by fever, rash, and joint pain. CHIKV has infected millions of people in Africa, Asia, America, and Europe since it re‐emerged in the Indian Ocean region in 2004. Here, we report an outbreak of Chikungunya fever that occurred in Ruili of Yunnan Province, a city located on the border between China and Myanmar, in September 2019. The outbreak lasted for three months from September to December. Overall, 112 cases were confirmed by a real‐time reverse‐transcription polymerase chain reaction in the Ruili People's Hospital, and they showed apparent temporal, spatial, and population aggregation. Among them, 91 were local cases distributed in 19 communities of Ruili City, and 21 were imported cases. The number of female patients was higher than that of male patients, and most patients were between 20 and 60 years old. The main clinical manifestations included joint pain (91.96%), fever (86.61%), fatigue (58.04%), chills (57.14%), rash (48.21%), headache (39.29%), and so forth. Biochemical indexes revealed increased C‐reactive protein (63.39%), lymphopenia (57.17%), increased hemoglobin (33.04%), neutrophilia (28.57%), and thrombocytopenia (16.07%). Phylogenetic analysis of the complete sequences indicated that the CHIKV strains in this outbreak belonged to the Indian Ocean clade of the East/Central/South African genotype. We speculated that this chikungunya outbreak might be caused by CHIKV‐infected persons returning from Myanmar, and provided a reference for the formulation of effective treatment and prevention measures. Highlights: One of the longest CHIKV epidemics in China was described, lasting for three months.All cases showed apparent temporal, spatial and population aggregation.The CHIKV strains belonged to the Indian Ocean clade of the ECSA genotype.The first vertical transmission of CHIKV in China was recorded. [ABSTRACT FROM AUTHOR]

Malaria cases have dramatically declined in China along the Myanmar border, attributed mainly to adoption of the 1-3-7 surveillance and response approach. No indigenous cases have been reported in China since 2017. Counties in the middle and southern part of the border area have a higher risk for malaria importation and reestablishment after elimination. [ABSTRACT FROM AUTHOR]

The outbreak of coronavirus disease 2019 (COVID-19) has caused more than 80 813 confirmed cases in all provinces of China, and 21 110 cases reported in 93 countries of six continents as of 7 March 2020 since middle December 2019. Due to biological nature of the novel coronavirus, named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with faster spreading and unknown transmission pattern, it makes us in a difficulty position to contain the disease transmission globally. To date, we have found it is one of the greatest challenges to human beings in fighting against COVID-19 in the history, because SARS-CoV-2 is different from SARS-CoV and MERS-CoV in terms of biological features and transmissibility, and also found the containment strategies including the non-pharmaceutical public health measures implemented in China are effective and successful. In order to prevent a potential pandemic-level outbreak of COVID-19, we, as a community of shared future for mankind, recommend for all international leaders to support preparedness in low and middle income countries especially, take strong global interventions by using old approaches or new tools, mobilize global resources to equip hospital facilities and supplies to protect noisome infections and to provide personal protective tools such as facemask to general population, and quickly initiate research projects on drug and vaccine development. We also recommend for the international community to develop better coordination, cooperation, and strong solidarity in the joint efforts of fighting against COVID-19 spreading recommended by the joint mission report of the WHO-China experts, against violating the International Health Regulation (WHO, 2005), and against stigmatization, in order to eventually win the battle against our common enemy — COVID-19. [ABSTRACT FROM AUTHOR]

In this study, we isolated a virus strain (YN12031) from specimens of Armigeres subalbatus collected in the China-Laos border. BHK-21 cells infected with YN12031 exhibited an evident cytopathic effect (CPE) 32 h post-infection. The virus particles were spherical, 70 nm in diameter, and enveloped; they also featured surface fibers. Molecular genetic analysis revealed that YN12031 was closely related to alpha viruses such as Chikungunya virus and Sindbis virus, and located in the same clade as MM2021, the prototype of Getahvirus (GETV) isolated in Malaysia in 1955. Phylogenetic analysis of the E2 and capsid genes further revealed that YN12031 was located in the same clade as the Russian isolate LEIV/16275/Mag. Analysis of the homology of nucleotides and amino acids in the coding area and E2 gene demonstrated that the YN12031 isolated from the China-Laos border (tropical region) was related closest to the LEIV/16275/Mag isolate obtained in Russia (North frigid zone area) among other isolates studied. These results suggest that GETV can adapt to different geographical environments to propagate and evolve. Thus, strengthening the detection and monitoring of GETV and its related diseases is very crucial. [ABSTRACT FROM AUTHOR]

To understand how malaria could be eliminated in the original hyperendmic area for malaria along international borders in Yunnan Province, malaria situation and control were described on the basis of seven phases. At last the experiences and lessons of the program that reduced border malaria from hyperendmicity to malaria-free status were summarized. Malaria control and elimination area were particularly difficult in the Yunnan border. The achievement can be attributed to high political commitment, strategic and technical innovations based on the actual locality, effective collaboration and communication with neighbouring countries to carry out cross border interventions. Other border areas might perform their own pilot interventions based on their local context, including malaria burden, governing system, health service structure contextualized based on their socioeconomic development and ecology, and then a local decision could be made according to their own trial results., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

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.

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.

Objective: To investigate the resistance level of Culex tritaeniorhynchus to DDT and deltamethrin in Yunnan Province., Methods: Adult Culex tritaeniorhynchus samples were collected in Zhaoyang District of Zhaotong City, Mangshi County of Dehong Prefecture, Yuanjiang County of Yuxi City, Jiangcheng and Menglian County of Puer City. The susceptibility of Cx. tritaeniorhynchus to DDT and deltamethrin were tested by bioassay method. The resistance level was judged by adjusted mortality., Results: Culex tritaeniorhynchus collected from Zhaoyang, Mangshi, Jiangcheng, Menglian, and Yuanjiang, and exposed to DDT for 1 h, the mortality after 24 hours was 51.1%, 86.8%, 35.4%, 21.0%, and 4.6%, respectively; the resistant grade in Mangshi was maybe resistance(M), and the others 4 sites were resistance (R). The range of KT, to DDT was from 18.76 min to 395.65 min. The mortality of the mosquitoes from the five sites to deltamethrin was 36.9%, 59.2%, 43.1%, 34.1%, and 3.3%, respectively; the resistant grade was R in all sites, and the range of KT50 was 8.69-715.37 min., Conclusion: Culex tritaeniorhynchus in Yunnan Province shows simultaneously resistant to DDT and deltamethrin, and therefore the insecticiding strategy should be adjusted.

Objective: To understand the status of Toxoplasma gondii infection in the population of Pu'er City, so as to provide the evidence for formulating the strategy of toxoplasmosis control., Methods: The population from Jingdong, Jinggu, and Menglian counties in Pu' er City was surveyed; IgG of T. gondii in serum was detected by ELISA., Results: Totally 906 resident serum samples were detected and the IgG positive rate was 24.2%. The positive rates were higher in the aged groups of 30-39 years and 60-69 years, and the difference among different aged groups was significant (Χ2 = 17.77, P < 0.01). There were no significant differences between different sexualities, and among different educational levels and living habits (P > 0.05). The positive rates were 26.6% (194/730), 15.5% (22/142), and 8.8% (3/34) in farmers, students and other occupations, respectively, and there was a significant difference among them (Χ2 = 12.51, P < 0.01). The positive rates were 23.3% (198/849)and 36.8% (21/57) in the farmers who had the habit of rearing pigs in pens and the farmers who had the habit of free ranging pigs, respectively, and there was a significant difference between them (Χ2 = 5.33, P < 0.05)., Conclusion: The IgG positive rate of T. gondii is very high in Pu'er City, and therefore, the health education for toxoplasmosis control should be strengthened.

From June to August 2012, the blood-sucking mosquitoes were captured around cattle-sheds and human houses in Yuanjiang County, Qiaojia County, Yongshan County, and Jinghong City of Yunan Province. Blood samples from mosquitoes were collected on filter paper. Multiplex PCR assay was used to detect the blood meal samples. Among the 145 mosquitoes captured, 123 were Anopheles sinensis (84.8%) and 22 A. minimus (15.2%). Among the blood samples, corresponding bands were amplified in 134 samples. The result showed that the blood meals were from pigs (n = 104), cows (n = 22), dogs (n = 4), human (n=2), cow and pig (n = 1), pig and human (n = 1). Human blood index of A. sinensis and A. minimus was 0.018 and 0.045, respectively.

The energy of the physiological activities for both male and female mosquitoes is provided by feeding sugar outdoors. The attractive toxic sugar bait (ATSB) was developed according to the behavior, and showed a good result in reducing mosquito population size. This paper introduces the progress on the sugar-feeding behavior of mosquitoes and application in vector-borne disease control.

Objective: To assess the in vitro sensitivity of Plasmodium falciparum to chloroquine, piperaquine and pyronaridine in China-Myanmar border area., Methods: Fifty-one blood specimens of P. falciparum isolates were collected from Laza City of Myanmar during September to December in 2009, and the sensitivity of the parasites to the drugs was detected by Rieckmann's in vitro microtest., Results: Among the 42 blood samples with valid results of sensitivity test, the resistance rate to chloroquine, piperaquine and pyronaridine was 95.2%, 7.1%, and 54.8%, with a corresponding 50% inhibition dose (IDn) of 320.5, 128.2, and 96.0 nmol/L, respectively. Pyronaridine-resistant P. falciparum exhibited some degree of cross-resistance to chloroquine [91.3%(21/23)] and piperaquine [13.0% (3/23)], and chloroquine-resistant P. falciparum showed cross-resistance to piperaquine [7.5%(3/40)] and pyronaridine [52.5%(21/40)]. High level of cross-resistance was present to chloroquine (100%) and pyronaridine (100%) in piperaquine resistant P. falciparum., Conclusion: In Laza City, P. falciparum shows high resistance to chloroquine, half isolates are resistant to pyronaridine, and most isolates are still sensitive to piperaquine.

Objective: To make an epidemiological investigation on malaria in Motuo County, Linzhi Prefecture of Tibet., Methods: In July of the year 2006, the following activities were conducted in 2 selected villages from each of the three townships, i.e., Motuo, Dexing and Beibeng: malaria history survey among inhabitants in recent 2 years; collection of blood samples of inhabitants for examining malaria parasites, IFAT and detecting G6PD, respectively; mosquito collection in human dwellings and cattle shelters at night and various resting sites at day-time; mosquito collection by outdoor human baiting capture; classification and composition calculation of mosquito species and man biting rates; ELISA for detecting sporozoite infection of Anopheles., Results: The mean rate of two-year malaria history was 8.98% (118/1314) and the parasite rate was 3.13% (38/1216, all P. vivax) in the inhabitants. The parasite positive rate among the feverish patients was 7.14% (3/42). IFAT revealed a malaria antibody rate of 40.24% (472/1173). The G6PD deficiency rate was 1.74% (21/1208). Five hundred and thirteen anopheline mosquitoes were caught. They were An. maculatus (474) which occupied 92.4% (474/513), An. peditaeniatus (35), An. kochi (3) and An. sinensis (1). The mean indoor density of An. maculatus was 4.75/night in human houses, and 69.5/night in cattle shelters. The outdoor human biting rate was 22.75/half-night/person, and the sporozoite rate of An. maculatus in anopheline saliva glands was 0 by ELISA., Conclusion: Motuo County is an endemic area of vivax malaria with An. maculatus as the potential vector.

Objective: To interpret genetic variation and population structure of Anopheles dirus A and D from China by molecular marker., Methods: Samples included An. dirus A of Hainan laboratory colony (n=13), and field specimen from Mengla (n=17) and Jiangcheng (n=17) in Yunnan Province. The specimens were identified by PCR assay before study, mtDNA-CO I region was amplified and sequenced. Genetic variation and population structure was estimated according to sequence data., Results: The mtDNA-CO I gene with a length of 959 bp was analyzed. There were three haplotypes in An. dirus A and six haplotypes in An. dirus D. The above haplotypes distributed in three populations uniformly. The average number of pairwise differences within Mengla population (7.4412) was greater than that of Jiangcheng (1.2794) and Hainan (1.0513) populations, which suggested that the level of genetic divergence was the highest within Mengla population. The result of hierarchical AMOVA estimation showed a limited geneflow (Fst=0.799 9), therefore the variation level in a population (20.01%) was smaller than among the populations (79.99%)., Conclusion: The inter-specific genetic variation between An. dirus A and D in China was small and the level of divergence among individuals was high.

Objective: To detect circumsporozoite protein (CSP) in anopheline vectors from south Yunnan and to evaluate ELISA in the detection., Methods: Salivary glands of the anopheline mosquitoes were taken for finding sporozoites by microscopy and part of the glands was used for detecting CSP by ELISA. An. minimus was experimentally infected by blood from vivax malaria patient (with Plasmodium vivax) and examined for sporozoites and CSP. Eight species of anopheline mosquitoes were caught in the field and examined. Monoclonal antibodies to P. falciparum (Pf2A10) and P. vivax (Pv210, Pv247) were used in ELISA for detecting CSP., Results: Sporozoites were found in the salivary glands of 27 out of 36 An. minimus experimentally infected (75.0%), 29 were ELISA CSP positives (80.6%), and 26 of the 27 mosquitoes showed Pv210 CSP positive. Among 1010 parous anopheline mosquitoes from the field, 7 were found sporozoite positive (0.69%), 8 were ELISA CSP positive (0.79%), and 6 of the 7 mosquitoes showed CSP positive. Of 4675 wild mosquitoes in 8 anopheline species with different ages, 11 were found CSP positive (0.24%) including An. minimus, An. sinensis and An. maculatus with a positive rate of 0.20%, 0.24% and 0.39% respectively. Among the 11 mosquitoes, 9 were Pv210 positive and 2 were Pf2A10 positive., Conclusion: CSP detection by ELISA is a useful method to monitor the malaria transmission capacity of anopheline vectors.