The authors carried out two series of field test to determine the basic lines of DDT and Dieldrin susceptibility of Anopheles sinensis at Andong(1961) and Yoju(1962), where malaria endemicity is relatively high in Korea. Tests were performed in accordance with the standard method established by the World Health Oraganization(1960). The results were summarized as follows: The LC-50 of DDT for A. sinensis caught at Andong as 1.5 %, while for the same species in Yoju was 1.3 %. The LC-50 of Dieldrin for A. sinensis caught at Andong was 0.075 %, while the LC-50 for the same species at Yoju was 0.07 %. These results therefore indicate Anopheles sinensis, as the malaria vector species in Korea, is susceptible to DDT and Dieldrin.
parasitology-protozoa-Plasmodium vivax ; chemotherapy-malaria ; Anopheles sinensis ; DDT ; Dieldrin

The species composition, population density, and seasonal prevalence of vector mosquitoes in an inland area of Kyungpook province were studied, based on light trap and human bait trap collections, and the recent patterns of infestation for infective larvae of Brugia malayi in these vector hosts were investigated from May to November in 1985. Nine species in four genera of mosquitoes were collected by light trap, human bait trap, and/or by nets. Anopheles sinensis Wiedemann was the most abundant species collected by light traps during this year. Culex tritaeniorhychus Giles was the second abundant species, and Aedes vexans nipponii(Theobald) ranked third in total abundance. The earlist time when A. sinensis were found was the middle of May. At that time the temperature ranged from 14.3 C to 22.8 C and the humidity 53-90 per cent. The month of highest average nightly catch was July, when the temperature was betweeen 21.5 C and 30.6 C and the humidity 72-91 per cent. The peak time of biting activity of mosquitoes was different in each month, i.e. between 22:00-23:00 in July, and 20:00-21:00 hours in September, when the temperature was between 24.3 C and 26.5 C and the humidity 73-88 per cent in the field. While infective larvae of B. malayi were reported to have been found in one species of mosquito in 1975, no larvae were found in any species collected in this survey.
parasitology-helminth-nematoda ; arthropoda ; Brugia malayi ; Anopheles sinensis ; epidemiology

Vivax malaria is a significant military and civilian health threat in the north of the Republic of Korea (ROK). The island of Baengnyeong-do is the westernmost point of the ROK and is located close to the southwestern coast of the Democratic People's Republic of Korea (DPRK). Mosquitoes were collected using a black light trap on Baengnyeong-do, and Anopheles spp. were assayed by PCR, to identify the species, and screened for sporozoites of Plasmodium vivax. Of a subsample of 257 mosquitoes, Anopheles lesteri was the most frequently collected (49.8%), followed by Anopheles sinensis (22.6%), Anopheles pullus (18.7%), Anopheles kleini (7.8%), and Anopheles belenrae (1.2%). The overall sporozoite rate was 3.1%, with the highest rates observed in An. kleini (15.0%), An. sinensis (5.2%), and An. lesteri (1.6%). No sporozoite positive An. pullus or An. belenrae were observed. The results extend our knowledge of the distribution and potential role in malaria transmission of An. kleini, An. lesteri, and An. sinensis, for an area previously considered to be at a low risk for contracting vivax malaria.
Animals ; Anopheles/*classification/genetics/*parasitology ; Plasmodium vivax/genetics/*isolation & purification ; Polymerase Chain Reaction ; Prevalence ; Republic of Korea

During the summer season(July-August) in 1967, the insecticide tests for resistance on adult A. sinensis and C. tritaeniorhynchus were carried out in Gobu-Myun Jeongup-Gun, Chollapuk-Do, where many Japanese encephalitis cases occur every year. The mortality by 4.0% DDT in A. sinensis was 88.9% and by 4.0% dieldrin was 84.4%. Therefore the LC-50 of DDT for A. sinensis was 1.75%, while LC-50 of dieldrin was 1.1%. The mortality by 4.0% DDT in C. tritaeniorhynchus was 36.7%, and by 4.0% dieldrin was 6.0% The result indicates that A. sinensis in Korea is susceptible to DDT and resistant to dieldrin. C. tritaeniorhynchus is highly resistant to both DDT and dieldrin.
parasitology-arthropoda ; vector ; mosquito ; Culex tritaeniorhynchus ; Anopheles sinensis ; chemotherapy ; DDT ; dieldrin

On epidemiological grounds, Anopheles sinensis has been suspected for many years to be the malaria vector in Korea. Of 7,517 dissections of A. sinensis, one specimen was found for the first time in Korea naturally infected with sporozoites in August 1962. Experimental infection of A. sinensis with Plasmodium vivax had been successfully conducted at earlier date.
mosquito-parasitology ; malaria-vector ; arthrooda-Anopheles sinensis ; protozoa-Plasmodium vivax ; epidemiology-Korea

In order to determine the seasonal prevalence and population density of vector mosquitoes in Kyungpook province, a survey based on average number of female mosquito per trap-night, were carried out during the period from May to November in 1984. Among the 34,571 mosquitoes collected in Kyungsan county in animal shelters and human dwellings by light traps, approximately 45.0 % were Culex tritaeniorhynchus, 34. 0 % per cent Culex pipiens pallens, and 19.0 per cent Anopheles sinensis. By comparison, distribution of mosquito species in Ankang town, in which Japanese encephalitis had been reported in the past, were quite different and A. sinensis was the most abundant species, being constituted in 75.8 per cent, followed by C. tritaeniorhynchus(23. 2 percent), and C. pipiens pallens(0. 6 per cent). In the general patten of seasonal prevalence, C. tritaeniorhynchus first appeared in mid-June, and trapped in large numbers during the periods from mid-August to early September, showing a simple sharply pointed one-peaked curve, while C. pipiens pallens was found to be active through almost the entire season showing irregular curves with several peaks. The trend of seasonal distribution of A. sinensis was similar to that of C. tritaeniorhynchus, but the earliest dates of appearance and disappearance different form that of C. tritaeniorhynchus. The results of hourly catches of mosquitoes by human baited traps have clearly shown the differences in the biting rhythm among the vector mosquitoes of this province, such as the facts that C. tritaeniorhynchus and A. sinensis are rather constantly active all through a night with more or less inconspicuous peaks twice a night, while C. pipiens pallens exhibits an irregular curve, and the numbers of A. vexans nipponii, C. vagans and Armigeres subalbatus are very small and are not sufficient for estimating the biting rhythm. Four genera and fourteen species of larval mosquitoes collected from eighteen kinds of habitats which classified according to the categories followed by Bates(1949). The main breeding sites contributing to peak C. tritaeniorhynchus adult densities in this surveyed areas were evidently ricefields, ground pools, puddles and swamps and marshes, etc. Summarizing the results, this study indicated that the highest population density of C. tritaeniorhynchus was encountered in late August and early September, showing simple sharply pointed one-peaked curve.
parasitology-arthropoda ; mosquito-epidemiology ; Culex tritaeniorhynchus ; Culex pipiens pallens ; Anopheles sinensis

This paper is the result of adult female mosquito and larval collection in U.S. Army Installations in Korea from 1979 to 1983. New Jersey light traps ere operated for ault collection from May to October. The primary concern of this surveillance is to determine when to recommend insecticide spraying for mosquito control in the Army areas. The 5th Preventive Medicine Unit have developed an "index" level of female mosquitoes in a light trap similar to other U.S.Army Agencies in other parts of the world. When 10 female mosquitoes are reached on two consecutive trap-night, or 5 known vector females are collected, fogging is recommended in the trap areas. Mosquito collections were conducted in 12 U.S. Army areas by operating 39 New Jersey light traps. Mosquitoes collected from the areas were identified to be 17 species comprising 3 genera. Anopheles sinensis(40%). Culex tritaeniorhyncus(31%), Aedes vexans nipponii(19%), and Culex pipiens pallens(10%) appeared to be the most common species in the area. The species, population density and monthly appearance of adult mosquitoes were found to be almost the same in the all provinces involved. And Japanese encephalitis vector mosquitoes, Culex tritaeniorhyncus, showed their seasonal fluctuation from July to September with a peak in August each year. 3. Larval habitats confirmed in the Army areas were categorized into 16 types as shown in Table The mosquito larvae collected in those habitats were identified to be 15 species representign 4 genera. Most breeding sites in the Army areas were those which are activated during the wet season. More mosquitoes were collected from the Kyungki province than from the other provinces. The reason for more collection of mosquitoes from military installations in the Kyungki provinces appears to be the geographic characteritics surrounded by rice fields, marshes and other stagnant water areas.
parasitology-arthropoda-mosquito ; taxonomy ; epidemiology ; Anopheles sinensis ; Culex tritaeniorhyncus ; Aedes vexans nipponii ; Culex pipiens pallens

To evaluate the factors that determine the transmission level of vivax malaria using vectorial capacity, entomological surveys were conducted from June to August, 2000. From 6 nights of human-bait collection in Paju, the human biting rate (ma) was counted as 87.5 bites/man/night. The parity of Anopheles sinensis from human baiting collections fluctuated from 41% to 71% (average 48.8%) of which the rate gradually increased as time passed on: 35.2% in Jun.; 55.0% in July; 66.2% in Aug. From this proportion of parous, we could estimate the probability of daily survival rate of An. sinensis to be 0.79 assumed with 3 days gonotrophic cycle and the expectancy of infective life through 11 days could be defined as 0.073. Blood meal analysis was performed using ELISA to determine the blood meal source. Only 0.8% of blood meals were from human hosts. We could conclude that An. sinensis is highly zoophilic (cow 61.8%). Malaria is highly unstable (stability index < 0.5) in this area. From these data, vectorial capacity (VC) was determined to be 0.081. In spite of a high human biting rate (ma), malaria transmission potential is very low due to a low human blood index. Therefore, we could conclude that malaria transmission by An. sinensis is resulted by high population density, not by high transmission potential. For this reason, we need more effort to decrease vector population and vector-human contact to eradicate malaria in Korea.
Animals ; Anopheles/*parasitology ; Human ; Insect Vectors ; Korea ; Malaria, Vivax/parasitology/*transmission ; Parity ; Plasmodium vivax/*pathogenicity/physiology ; Population Density

The objectives of the present study were to (1) determine the susceptibility of Anopheles sinensis to Korean isolates of Plasmodium vivax, (2) establish a method to collect large quantities of P. vivax sporozoites for use as antigen in seroepidemiological studies, and (3) investigate the characteristics of Korean isolates of P. vivax sporozoites. Females of Anopheles sinensis were collected at non-epidemic area, Seokwha-ri, Cheongwon-gun and Chungcheongbuk-do using tent-trap methods coupled with dry ice. The females were artificially infected with gametocytes of P. vivax using blood obtained from P. vivax malaria patients. Individual mosquitoes were infected using either a parafilm-covered glass feeding apparatus or were allowed to feed on naturally infected volunteers. Mosquitoes were sacrificed between 16 and 18 days post-feeding and an enzyme-linked immunosorbent assay (ELISA) was used to detect sporozoites. Four (33.4%) of 12 mosquitoes, which were fed on naturally infected volunteers directly, were positive for sporozoites. In cases, the mosquitoes allowed to feed on whole blood which were extract from three different patients with heparin treated vacuutainers using a parafilm-covered glass apparatus. Two of 55 (3.6%) were positive which blood sample was maintained at room temperature for 8 hours, 1 of 68 (1.5%) was positive which blood was maintained at 4 degrees C for 24 hours and 1 of 47 (2.3%) was positive at 4 degrees C for 48 hours. The mean number of sporozoites was estimated about 818 (n = 8; range of 648-1,056) based on optical density values of ELISA.
Animals ; Anopheles/*parasitology ; Enzyme-Linked Immunosorbent Assay ; Human ; Korea ; Plasmodium vivax/isolation & purification/*pathogenicity ; Support, Non-U.S. Gov't

OBJECTIVETo identify the biological forms, sporozoite rate and molecular characterization of the Anopheles stephensi (An. stephensi) in Hormozgan and Sistan-Baluchistan provinces, the most important malarious areas in Iran.

METHODSWild live An. stephensi samples were collected from different malarious areas in southern Iran. The biological forms were identified based on number of egg-ridges. Molecular characterization of biological forms was verified by analysis of the mitochondrial cytochrome oxidase subunit I and II (mtDNA-COI/COII). The Plasmodium infection was examined in the wild female specimens by species-specific nested-PCR method.

RESULTSResults showed that all three biological forms including mysorensis, intermediate and type are present in the study areas. Molecular investigations revealed no genetic variation between mtDNA COI/COII sequences of the biological forms and no Plasmodium parasites was detected in the collected mosquito samples.

CONCLUSIONSPresence of three biological forms with identical sequences showed that the known biological forms belong to a single taxon and the various vectorial capacities reported for these forms are more likely corresponded to other epidemiological factors than to the morphotype of the populations. Lack of malaria parasite infection in An. stephensi, the most important vector of malaria, may be partly due to the success and achievement of ongoing active malaria control program in the region.

Animals ; Anopheles ; genetics ; parasitology ; DNA, Mitochondrial ; genetics ; DNA, Protozoan ; genetics ; Eggs ; classification ; parasitology ; Female ; Iran ; Male ; Parasite Load ; Plasmodium ; genetics ; isolation & purification ; Polymerase Chain Reaction ; Sporozoites