ABSTRACT
Malaria was one of the major infectious diseases in Jiangsu Province, where Anopheles sinensis and An. anthropophagus are main vectors for malaria transmission. Following the concerted efforts for decades, the goal of malaria elimination was achieved in Jiangsu Province in 2019, and the vector control strategy has played a vital role during the progress towards malaria elimination in Jiangsu Province. Hereby, we review the historical distribution and ecological features of An. sinensis and An. anthropophagus and describe vector control strategies at different stages of malaria control in Jiangsu Province. In addition, the advances in the research of vector biology and control in Jiangsu Province are discussed, including vector identification, strain colonization, susceptibility to malaria parasites and insecticide resistance.
ABSTRACT
Objective To evaluate the effect of malaria vector control measures so as to provide the evidence for consolidating the control effectiveness of malaria and carrying out the vector surveillance in Suizhou City. Methods The distributions of Anopheles sinensis and An. anthropophagus were investigated by the combination of retrospective review and field survey. The changes of density and population of mosquito vectors were investigated and compared among various years. Results From 1985 to 1996, both An. sinensis and An. anthropophagus were found in 18 towns, and An. anthropophagus mosquitoes accounted for 52.3% of the total Anopheles mosquitoes. Only An. sinensis mosquitoes were found in other 26 towns. In 2003 and 2004, An. anthropophagus mosquitoes were found in the original 18 towns, and they accounted for 47.0% and 38.1% respectively, but in 2005, An. anthropophagus mosquitoes were not found in this city. However, the density of An. sinensis presented an upward trend. Conclusions An. anthropophagus population has gradually disappeared in Suizhou City, and currently, An. sinensis is the main Anopheles population, which might be the malaria vector in suitable conditions. Therefore, the surveillance and control of Anophe les vector should be strengthened in order to consolidate the achievements of malaria elimination.
ABSTRACT
Objective To evaluate the effect of malaria vector control measures so as to provide the evidence for consolidating the control effectiveness of malaria and carrying out the vector surveillance in Suizhou City. Methods The distributions of Anopheles sinensis and An. anthropophagus were investigated by the combination of retrospective review and field survey. The changes of density and population of mosquito vectors were investigated and compared among various years. Results From 1985 to 1996, both An. sinensis and An. anthropophagus were found in 18 towns, and An. anthropophagus mosquitoes accounted for 52.3% of the total Anopheles mosquitoes. Only An. sinensis mosquitoes were found in other 26 towns. In 2003 and 2004, An. anthropophagus mosquitoes were found in the original 18 towns, and they accounted for 47.0% and 38.1% respectively, but in 2005, An. anthropophagus mosquitoes were not found in this city. However, the density of An. sinensis presented an upward trend. Conclusions An. anthropophagus population has gradually disappeared in Suizhou City, and currently, An. sinensis is the main Anopheles population, which might be the malaria vector in suitable conditions. Therefore, the surveillance and control of Anophe les vector should be strengthened in order to consolidate the achievements of malaria elimination.
ABSTRACT
Objective To investigate the malaria vectors in Nanyang City. Methods Two townships were selected as malaria vector surveillance sites in Nanyang City from 2005 to 2017, including Mazhenfu Township in Tanghe County and Huaiyuan Township in Tongbai County, and the malaria vectors were investigated using the semi-overnight human baiting trapping method and mosquito trapping in nets. Results The mean density of Anopheles sinensis was 0.65 to 22.30 mosquitos/(person · hour) in the two surveillance sites in Nanyang City using the human baiting trapping method from 2005 to 2017, and the peak density was detected in June and July. An. anthropophagus was captured only in Tongbai County during the period between 2008 and 2011, with a mean density of 0.03 to 1.10 mosquitos/(person · hour). The mean density of An. sinensis was 0.08 to 0.24 mosquitos/(net · night) using the mosquito trapping in nets from 2005 to 2011, and the peak density was detected in July and August, while few An. anthropophagus captured only in Tongbai County, with a mean density of 0.01 to 0.02 mosquitos/(net · night). Conclusions There are malaria vectors in Nanyang City, including An. sinensis and An. anthropophagus, and An. sinensis is the dominant mosquito species.
ABSTRACT
To identify the gene differentially expressed in female Anopheles anthropophagus and to analyze its gene sequence, this gene amplified by PCR was identified by real-time PCR and its cDNA was then amplified with rapid amplification of cDNA ends (RACE) technology. It was found that the expression ratio of the female differentially expressed gene in female and male mosquitoes was 267.49 according to the formula F=2~(-⊿⊿CT).The size of mRNA of the gene was 364 bp, and the amino acid sequence deduced from the open reading frame (ORF) was found to be similar to the sequence of tectin protein of Culex quinquefasciatus and proteins of other species. The mRNA sequence of this gene was submitted to NCBI with a accession number of FJ907236. This gene may provide a foundation for further studies on the biological functions of mosquitoes.
ABSTRACT
Objective] To clarify the taxonomic status of Anopheles lesteri and An.anthropophagus in China. [Methods] Using molecular identification (PCR assay and rDNA\|ITS2 sequencing) to examine the field anopheline mosquito specimens from Liaoning and Shandong. According to the ITS2 sequences, molecular phylogenetic tree was made. [Results] According to the molecular identification, An.lesteri and An.anthropophagus were distributed both in Liaoning Province and Shandong Province. The length and GC content of rDNA\|ITS2 sequence were 451 bp, 46 2% in An.lesteri (n=6), and 448 bp, 46 0% in An.anthropophagus (n=10), respectively. The ITS2 sequences from presentation sites were same in An.lesteri, while the intraspecies difference in An.anthropophagus was 0 88%. The specific difference between An.lesteri and An.anthropophagus was 25 7%. By analyzing molecular phylogenetic tree, the relationship between An.lesteri and An.sinensis, An.anthropophagus and An.liangshanensis was found to be closer. [Conclusion] According to the molecular identification, it was defined that An.lesteri and An.anthropophagus were sympatric independent species in China.
ABSTRACT
Objective To study the relationship between P450 (CYP6 and CYP4) genes and deltamethrin resistance in Anopheles anthropophagus. Methods The real-time RT-PCR technique was used for semi-quantitative analysis of mRNA copy numbers of CYP6 and CYP4 gene from susceptible and deltamethrin-resistant strains. Results It is found that the mRNA copy numbers of CYP6 gene in deltamethrin-resistant strain were about 1. 39 times higher than those in susceptible strain, and the mRNA copy numbers of CYP4 gene in deltamethrin-resistant strain were about 3. 63 times higher than those in susceptible strain of Anopheles anthropophagus. Conclusion The higher expressions of CYP6 and CYP4 mRNA are observed in deltamethrin resistance strain and indicate that both CYP6 and CYP4 genes may be involved in the deltamethrin resistance in Anopheles anthropophagus.
ABSTRACT
Objective To establish a fast and sensitive method to detect Plasmodium sporozoites in mosquitoes. Methods Anopheles anthropophagus (An.a) artificially infected with Plasmodium vivax (P.v), Anopheles dirus (An.d) infected with Plasmodium falciparum (P.f) and both of P.v and P.f, field mosquitoes of Anopheles sinensis (An.s) captured in epidemic seasons were detected by nested-PCR. Results The results of 28 batches of An.a infected with P.v, 2 batches of An.d with P.f and 1 batch of An.d mixed with P.v and P.f by nested-PCR were accorded with the microscopical examination absolutely. Two positives of 589 An.s field mosquitoes were discovered with a positive rate of 0.34%. Conclusion The nested-PCR is fast and sensitive for detecting different species of Plasmodium in mosquitoes.
ABSTRACT
Objective To analyze the genetic characteristics of deltamethrin resistant strain of Anopheles anthropophagus. Methods The study was performed with LC-P curve method for the genetic mode of deltamethrin resistant of An. anthropophagus. Results The resistant coefficient of F_1 generation from cross and reciprocal cross were 15.19 and 16. 66 respectively. The LC-P curve of F_1 generation got near to that of resistant parents (D=0.651). There were no obvious platforms in 50% mortality of BC generation and 25% - 75% mortality of F_2 generation.There were significant differences between the determining curve and theoretical cure in both BC and F_2 generations, P
ABSTRACT
Objective To compare the susceptibility of Anopheles anthropophagus from Jiangsu, Guangdong and Liaoning provinces in China to Plasmodium vivax.Methods The blood samples of patients with P. vivax in endemic areas of China were collected to feed the mosquitoes of An. anthropophagus from different areas by using the artificial in vitro membrane feeding system in the lab, and then the mosquitoes were dissected during the 7-9th day and on the 14th day after the feeding and the oocysts and sporozoites in the stomach and salivy gland of mosquitoes were counted. Results The mosquitoes from Jiangsu, Guangdong and Liaoning were simultaneously fed with the blood of 35 cases of P. vivax. The oocyst positive rates of An. anthropophagus from Jiangsu, Guangdong and Liaoning during the 7-9th day after the feeding were 68.57%, 60.00% and 68.57%, as well as the sporozoite positive rates of them on the 14th day after the feeding were 22.86%, 14.29% and 22.86%, respectively. On the 7th day after the feeding, 228, 235, 228 mosquitoes of An. anthropophagus from Jiangsu, Guangdong and Liaoning were dissected, and the positive mosquito rates with oocyst infection were 28.07%, 25.11% and 26.75%, respectively. On the 14th day after the feeding, 150, 142, 135 mosquitoes of An. anthropophagus from the three areas were dissected, the positive rates with sporozoite infection were 10.67%, 8.45% and 11.85%, respectively. The num-bers of mosquitoes dissected with infective grade("+","++","+++","++++") of sporozoites of An. anthropophagus from Jiangsu, Guangdong and Liaoning were 4, 3, 2, 7; 2, 2, 3, 7 and 1, 6, 3, 8, respectively. Conclusions An. anthropophagus from Jiangsu, Guangdong and Liaoning is susceptible to the parasites of Plasmodium vivax and there is no significant difference among the susceptibilities of An. anthropophagus from the three areas to Plasmodium vivax.
ABSTRACT
Objective To compare the growth of Plasmodium vivax in Anopheles sinensis(An.s) and Anopheles anthropophagus(An.a) during the periods of malaria clinic attack and diapause. Methods The blood samples of patients during the clinic attack and diapause of vivax malaria patients in the vivax epidemic area in China were collected, feeding the mosquitoes of An.s and An.a by using the artificial membrane feeding system in vivo in the lab, and the mosquitoes were dissected during the day 7-9th and 14th after the infection and the oocysts and sporozoites in the stomach and gland of the mosquitoes were counted, respectively. Results The oocyst positive rate in An.s fed by Plasmodium vivax during the fever stage was lower than that in non-fever stage, the sporozoite positive rate in An.a fed by Plasmodium vivax during the fever stage was lower than that in non-fever stage. The positive mosquito rate with oocyst and sporozoite infected by Plasmodium vivax in the fever stage to An.s and An.a were lower than those in non-fever stage. The infective sporozoite intensity of An.s fed by Plasmodium vivax in the fever stage was lower than that in non-fever stage, but the reverse result was found to An.a. Conclusion There is a significant difference between the periods of malaria clinic attack and diapause of the oocyst and sporozoite infection to An.s and An.a.
ABSTRACT
ObjectiveTo observe the effectiveness of Responsar against Anopheles sinensis and Anopheles anthropophagus. MethodsThe cotton and nylon gauze absorbing Responsar solutions of 10,15 and 20 mg/m~2 (effective dosage) were used in the test. An. sinensis and An. anthropophagus raised in the lab were used as probational worms, having the knockdown power, lethiferous power and effective keeping observation. ResultsWith Responsar of 10,15 and 20 (mg/m~2) impregnating two different kinds of bednets, the KT_(50(s)) of An. sinensis and An. anthropophagus were between 3.98 and 7.30 min after touching the bednets. The knocked down mosquitoes were resumed breeding for 24 h, and the mortality was 100%. Touching nets 3 min, resuming breeding for 24 h, the mortality of mosquitoes was more than 90%. The nets hung for 180 d after impregnated with the insecticide and the knockdown power was still between 8.57 and 16.31 min for Anopheles vector, and resuming breeding for 24 h, the mortality was still 100%. ConclusionThere is strong deadly effect of Responsar to Anopheles sinensis and Anopheles anthropophagus, and the effect can keep more than 180 d.
ABSTRACT
Objective To obtain cDNA fragment of CYP6 gene from Anopheles anthropophagus. Methods The degenerate RT-PCR technique was used to amplify the CYP6 mRNA from susceptible and deltamethrin-resistant strains of An.anthropophagus. The specific cDNA fragments were sequenced and analyzed. Results The 250 bp specific cDNA fragments of CYP6 gene from both susceptible and resistant strains were cloned and sequenced by the Direct Cloning Method. Total of 10 sequences, including 2 from susceptible strain and 8 from resistant strain, were obtained. Compared with P450 sequence databases from GenBank, all of the 10 sequences obtained were new P450 sequence and were lodged in GenBank (Accession numbers: AY273927-AY273936). According to being checked up by Nomenclature Committee of Cytochrome P450, 7 of them were confirmed as the new CYP6 genes and the others were alleles and all of them belonged to the subfamilies CYP6Z, CYP6P, CYP6N and CYP6M in CYP6 family, respectively. Conclusion The cloned 10 sequences are gene fragments from members of CYP6 family.[
ABSTRACT
This paper deals with the taxonomic status and specific names of Anopheles anthropophagus and An. lesteri, the important malaria transmitting vector in China. Based on a historical review of the literature recorded from the country, substantial evidence from morphological and molecular biological studies gives reason to convince that An. anthropophagus is a synonym of An. lesteri. A resurrection of the specific name of An. lesteri Baisas et Hu, 1936 brooks no delay.