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Vector bionomics and malaria transmission in the Upper Orinoco River, Southern Venezuela

Magris,Magda; Rubio-Palis,Yasmin; Menares,Cristóbal; Villegas,Leopoldo
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2007 EN
Relevância na Pesquisa
36.04%
A longitudinal epidemiological and entomological study was carried out in Ocamo, Upper Orinoco River, between January 1994 and February 1995 to understand the dynamics of malaria transmission in this area. Malaria transmission occurs throughout the year with a peak in June at the beginning of the rainy season. The Annual Parasite Index was 1,279 per 1,000 populations at risk. Plasmodium falciparum infections accounted for 64% of all infections, P. vivax for 28%, and P. malariae for 4%. Mixed P. falciparum/P. vivax infections were diagnosed in 15 people representing 4% of total cases. Children under 10 years accounted for 58% of the cases; the risk for malaria in this age group was 77% higher than for those in the greater than 50 years age group. Anopheles darlingi was the predominant anopheline species landing on humans indoors with a biting peak between midnight and dawn. A significant positive correlation was found between malaria monthly incidence and mean number of An. darlingi caught. There was not a significant relationship between mean number of An. darlingi and rainfall or between incidence and rainfall. A total of 7295 anophelines were assayed by ELISA for detection of Plasmodium circumsporozoite (CS) protein. Only An. darlingi (55) was positive for CS proteins of P. falciparum (0.42%)...

Malaria entomological inoculation rates in gold mining areas of Southern Venezuela

Moreno,Jorge E; Rubio-Palis,Yasmín; Páez,Elisa; Pérez,Enrique; Sánchez,Víctor; Vaccari,Elena
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2009 EN
Relevância na Pesquisa
46.65%
A longitudinal study of malaria vectors aiming to describe the intensity of transmission was carried out in five villages of Southern Venezuela between January 1999-April 2000. The man-biting, sporozoite and entomological inoculation rates (EIR) were calculated based on 121 all-night collections of anophelines landing on humans, CDC light traps and ultra violet up-draft traps. A total of 6,027 female mosquitoes representing seven species were collected. The most abundant species were Anopheles marajoara Galvão & Damasceno (56.7%) and Anopheles darlingi Root (33%), which together accounted for 89.7% of the total anophelines collected. The mean biting rate for An. marajoara was 1.27 (SD + 0.81); it was 0.74 (SD + 0.91) for An. darlingand 0.11 (SD + 0.10) for Anopheles neomaculipalpus Curry and the overall biting rate was 2.29 (SD + 1.06). A total of 5,886 mosquitoes collected by all three methods were assayed by ELISA and 28 pools, equivalent to 28 mosquitoes, yielded positive results for Plasmodium spp. CS protein. An. neomaculipalpus had the highest sporozoite rate 0.84% (3/356), followed by An. darlingi 0.82% (16/1,948) and An. marajoara 0.27% (9/3,332). The overall sporozoite rate was 0.48% (28/5,886). The rates of infection by Plasmodium species in mosquitoes were 0.37% (22/5...

Distribution of sibling species of Anopheles culicifacies s.l. and Anopheles fluviatilis s.l. and their vectorial capacity in eight different malaria endemic districts of Orissa, India

Tripathy,Asima; Samanta,Luna; Das,Sachidananda; Parida,Sarat Kumar; Marai,Nitisheel; Hazra,Rupenansu Kumar; Kar,Santanu Kumar; Mahapatra,Namita
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2010 EN
Relevância na Pesquisa
36.25%
The study was undertaken in eight endemic districts of Orissa, India, to find the members of the species complexes of Anopheles culicifacies and Anopheles fluviatilis and their distribution patterns. The study area included six forested districts (Keonjhar, Angul, Dhenkanal, Ganjam, Nayagarh and Khurda) and two non-forested coastal districts (Puri and Jagatsingpur) studied over a period of two years (June 2007-May 2009). An. culicifacies A, B, C and D and An. fluviatilis S and T sibling species were reported. The prevalence of An. culicifacies A ranged from 4.2-8.41%, B from 54.96-76.92%, C from 23.08-33.62% and D from 1.85-5.94% (D was reported for the first time in Orissa, except for occurrences in the Khurda and Nayagarh districts). The anthropophilic indices (AI) were 3.2-4.8%, 0.5-1.7%, 0.7-1.37% and 0.91-1.35% for A, B, C and D, respectively, whereas the sporozoite rates (SR) were 0.49-0.54%, 0%, 0.28-0.37% and 0.41-0.46% for A, B, C and D, respectively. An. fluviatilis showed a similarly varied distribution pattern in which S was predominant (84.3% overall); its AI and SR values ranged from 60.7-90.4% and 1.2-2.32%, respectively. The study observed that the co-existence of potential vector sibling species of An. culicifacies (A...

Toxoplasma Gondii Bradyzoites Form Spontaneously during Sporozoite-Initiated Development†

Jerome, M. E.; Radke, J. R.; Bohne, W.; Roos, D. S.; White, M. W.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /10/1998 EN
Relevância na Pesquisa
26.61%
Tachyzoites (VEG strain) that emerge from host cells infected with Toxoplasma gondii sporozoites proliferate relatively fast and double their number every 6 h. This rate of growth is intrinsic, as neither the number of host cells invaded nor host cell type appears to influence emergent tachyzoite replication. Fast tachyzoite growth was not persistent, and following ∼20 divisions, the population uniformly shifted to slower growth. Parasites 10 days post-sporozoite infection doubled only once every 15 h and, unlike emergent tachyzoites, they grew at this slower rate over several months of continuous cell culture. The spontaneous change in tachyzoite growth rate preceded the expression of the bradyzoite-specific marker, BAG1. Within 24 h of the growth shift, 2% of the population expressed BAG1, and by 15 days post-sporozoite infection, 50% of the parasites were positive for this marker. Spontaneous BAG1 expression was not observed in sporozoites or in tachyzoites during fast growth (through day 6 post-sporozoite inoculation), although these tachyzoites could be induced to express BAG1 earlier by culturing sporozoite-infected cells at pH 8.3. However, alkaline treatment also reduced the replication of emergent tachyzoites to the rate of growth-shifted parasites...

Efficiency of salivary gland invasion by malaria sporozoites is controlled by rapid sporozoite destruction in the mosquito hemocoel

Hillyer, Julián F.; Barreau, Catherine; Vernick, Kenneth D.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.46%
For successful transmission to the vertebrate host, malaria sporozoites must migrate from the mosquito midgut to the salivary glands. Here, using purified sporozoites inoculated into the mosquito hemocoel, we show that salivary gland invasion is inefficient and that sporozoites have a narrow window of opportunity for salivary gland invasion. Only 19% of sporozoites invade the salivary glands, all invasion occurs within 8 h at a rate of approximately 200 sporozoites per hour, and sporozoites that fail to invade within this time rapidly die and are degraded. Then, using natural release of sporozoites from oocysts, we show that hemolymph flow through the dorsal vessel facilitates proper invasion. Most mosquitoes had low steady-state numbers of circulating sporozoites, which is remarkable given the thousands of sporozoites released per oocyst, and suggests that sporozoite degradation is a rapid immune process most efficient in regions of high hemolymph flow. Only 2% of Anopheles gambiae hemocytes phagocytized Plasmodium berghei sporozoites, a rate insufficient to explain the extent of sporozoite clearance. Greater than 95% of hemocytes phagocytized Escherichia coli or latex particles, indicating that their failure to sequester large numbers of sporozoites is not due to an inability to engage in phagocytosis. These results reveal the operation of an efficient sporozoite-killing and degradation machinery within the mosquito hemocoel...

Direct Microscopic Quantification of Dynamics of Plasmodium berghei Sporozoite Transmission from Mosquitoes to Mice▿

Jin, Yamei; Kebaier, Chahnaz; Vanderberg, Jerome
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.29%
The number of malaria sporozoites delivered to a host by mosquitoes is thought to have a significant influence on the subsequent course of the infection in the mammalian host. We did studies with Anopheles stephensi mosquitoes with salivary gland infections of Plasmodium berghei sporozoites expressing a red fluorescent protein. After individual mosquitoes fed on an ear pinna or the ventral abdomen of a mouse, fluorescence microscopy was used to count numbers of sporozoites. Mosquitoes allowed to feed on the ear for periods of 3 versus 15 min deposited means of 281 versus 452 sporozoites, respectively, into the skin; this may have epidemiological implications because mosquitoes can feed for longer periods of time on sleeping hosts. Mosquitoes feeding on the ventral abdomen injected sporozoites not only into the skin but also into the underlying peritoneal musculature. Although mosquitoes injected fewer sporozoites into the abdominal tissues, more of these were reingested into the mosquito midgut, probably a consequence of easier access to blood intake from the abdominal area. The most consistent parameter of sporozoite transmission dynamics under all conditions of mosquito probing and feeding was the relatively slow release rate of sporozoites (∼1 to 2.5 per second) from the mosquito proboscis. The numbers of sporozoites introduced into the host by mosquitoes and the transmission efficiencies of sporozoite delivery are multifactorial phenomena that vary with length of probing time...

Interferon-alpha and synthetic peptide malaria sporozoite vaccine in non-immune adults: antibody response after 40 weeks.

Stürchler, D.; Zimmer, G.; Berger, R.; Etlinger, H.; Fernex, M.; Matile, H.; Just, M.
Fonte: World Health Organization Publicador: World Health Organization
Tipo: Artigo de Revista Científica
Publicado em //1990 EN
Relevância na Pesquisa
26.16%
Adults with no known immunity to sporozoites received, i.m., at weeks 0 and 8 two single 200 micrograms doses of a peptide Plasmodium falciparum sporozoite vaccine conjugated to tetanus toxoid ((NANP)3-TT) plus placebo (group 1) or interferon-alpha (IFN-alpha) (group 2) and were followed for antibody responses at weeks 4, 12 and 40. Peak antibody responses were observed at week 12. At week 40, a greater than or equal to 4-fold increase in antibody titre to sporozoites in IFA, or to (NANP)50 in ELISA was still detectable in 6 of 12 (50%) volunteers in group 1 and in 16 of 25 (64%) in group 2. Peak antibody titres in IFA and ELISA decreased with a rate of 0.8% and 0.5% per week, respectively.

Epidemiological assessment of malaria transmission in an endemic area of East Pakistan and the significance of congenital immunity*

Khan, A. Q.; Talibi, S. A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em //1972 EN
Relevância na Pesquisa
25.91%
A longitudinal epidemiological study was carried out in a hyperendemic malarious area of East Pakistan. Transmission of malaria was observed with two peaks, one in the premonsoon period, the other in the pre-winter period. New infections occurred in 51.7% of the infants surveyed who were 2 months old or under when first examined: there were frequent superinfections. The maternal immunity passively transferred to the infants did not play a significant role in restricting the development of the asexual erythrocytic stage or that of gametocytes, as indicated by the fact that the average parasite density and the gametocyte counts were highest in the 0-2-month age group and declined with increasing age. Mosquitos were collected for identification and for dissection to determine parity, the sporozoite rate, the vectorial capacity, and other basic indices. An. minimus was the principal vector, but An. leucosphyrous was also found to be positive.

Malaria Vector Surveillance in Ganghwa-do, a Malaria-Endemic Area in the Republic of Korea

Oh, Sung Suck; Hur, Myung Je; Joo, Gwang Sig; Kim, Sung Tae; Go, Jong Myoung; Kim, Yong Hee; Lee, Wook Gyo; Shin, E Hyun
Fonte: The Korean Society for Parasitology Publicador: The Korean Society for Parasitology
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.43%
We investigated the seasonality of Anopheles mosquitoes, including its species composition, density, parity, and population densities of mosquitoes infected with the parasite in Ganghwa-do (Island), a vivax malaria endemic area in the Republic of Korea. Mosquitoes were collected periodically with a dry-ice-tent trap and a blacklight trap during the mosquito season (April-October) in 2008. Anopheles sinensis (94.9%) was the most abundant species collected, followed by Anopheles belenrae (3.8%), Anopheles pullus (1.2%), and Anopheles lesteri (0.1%). Hibernating Anopheles mosquitoes were also collected from December 2007 to March 2008. An. pullus (72.1%) was the most frequently collected, followed by An. sinensis (18.4%) and An. belenrae (9.5%). The composition of Anopheles species differed between the mosquito season and hibernation seasons. The parous rate fluctuated from 0% to 92.9%, and the highest rate was recorded on 10 September 2008. Sporozoite infections were detected by PCR in the head and thorax of female Anopheles mosquitoes. The annual sporozoite rate of mosquitoes was 0.11% (2 of 1,845 mosquitoes). The 2 mosquitoes that tested positive for sporozoites were An. sinensis. Malarial infections in anopheline mosquitoes from a population pool were also tried irrespective of the mosquito species. Nine of 2...

The Effect of Deltamethrin-treated Net Fencing around Cattle Enclosures on Outdoor-biting Mosquitoes in Kumasi, Ghana

Maia, Marta Ferreira; Abonuusum, Ayimbire; Lorenz, Lena Maria; Clausen, Peter-Henning; Bauer, Burkhard; Garms, Rolf; Kruppa, Thomas
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 19/09/2012 EN
Relevância na Pesquisa
25.91%
Classic vector control strategies target mosquitoes indoors as the main transmitters of malaria are indoor-biting and –resting mosquitoes. However, the intensive use of insecticide-treated bed-nets (ITNs) and indoor residual spraying have put selective pressure on mosquitoes to adapt in order to obtain human blood meals. Thus, early-evening and outdoor vector activity is becoming an increasing concern. This study assessed the effect of a deltamethrin-treated net (100 mg/m2) attached to a one-meter high fence around outdoor cattle enclosures on the number of mosquitoes landing on humans. Mosquitoes were collected from four cattle enclosures: Pen A – with cattle and no net; B – with cattle and protected by an untreated net; C – with cattle and protected by a deltamethrin-treated net; D – no cattle and no net. A total of 3217 culicines and 1017 anophelines were collected, of which 388 were Anopheles gambiae and 629 An. ziemanni. In the absence of cattle nearly 3 times more An. gambiae (p<0.0001) landed on humans. The deltamethrin-treated net significantly reduced (nearly three-fold, p<0.0001) culicine landings inside enclosures. The sporozoite rate of the zoophilic An. ziemanni, known to be a secondary malaria vector, was as high as that of the most competent vector An. gambiae; raising the potential of zoophilic species as secondary malaria vectors. After deployment of the ITNs a deltamethrin persistence of 9 months was observed despite exposure to African weather conditions. The outdoor use of ITNs resulted in a significant reduction of host-seeking culicines inside enclosures. Further studies investigating the effectiveness and spatial repellence of ITNs around other outdoor sites...

Molecular characterization, biological forms and sporozoite rate of Anopheles stephensi in southern Iran

Chavshin, Ali Reza; Oshaghi, Mohammad Ali; Vatandoost, Hasan; Hanafi-Bojd, Ahmad Ali; Raeisi, Ahmad; Nikpoor, Fatemeh
Fonte: Asian Pacific Tropical Medicine Press Publicador: Asian Pacific Tropical Medicine Press
Tipo: Artigo de Revista Científica
Publicado em /01/2014 EN
Relevância na Pesquisa
25.91%

Immunogenicity, protective efficacy and safety of a recombinant DNA vaccine encoding truncated Plasmodium yoelii sporozoite asparagine-rich protein 1 (PySAP1)

Zhao, Jia; Deng, Shu; Liang, Jiayuan; Cao, Yaming; Liu, Jun; Du, Feng; Shang, Hong; Cui, Liwang; Luo, Enjie
Fonte: Landes Bioscience Publicador: Landes Bioscience
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.29%
Although great efforts have been undertaken for the development of malaria vaccines, no completely effective malaria vaccines are available yet. Despite being clinically silent, the pre-erythrocytic stage is considered an ideal target for the development of malaria vaccines. Sporozoite asparagine-rich protein 1 (SAP1) is a sporozoite-localized protein that regulates the expression of UIS (upregulated in infectious sporozoites) genes, which are essential for the infectivity of sporozoites. In this study, a recombinant DNA vaccine encoding a predicted antigenic determinant region of Plasmodium yoelii SAP1 (PySAP1) was constructed. Immunization of mice with this DNA vaccine construct resulted in significant elevation of cytokines such as IFN-γ, IL-2, IL-4 and IL-10, and total IgG as compared with control groups immunized with either the empty DNA vector or saline. After challenge with sporozoites, the group receiving the DNA vaccine showed delayed development of parasitemia and prolonged survival time compared with the control group. The DNA vaccine provided partial protection against P. yoelii 17XL infection, with an overall protection rate of 20%. In addition, the DNA vaccine did not show integration into the host genome. Further studies of SAP1 are needed to test whether it can be used as subunit vaccine candidate.

Type II Fatty Acid Biosynthesis Is Essential for Plasmodium falciparum Sporozoite Development in the Midgut of Anopheles Mosquitoes

van Schaijk, Ben C. L.; Kumar, T. R. Santha; Vos, Martijn W.; Richman, Adam; van Gemert, Geert-Jan; Li, Tao; Eappen, Abraham G.; Williamson, Kim C.; Morahan, Belinda J.; Fishbaugher, Matt; Kennedy, Mark; Camargo, Nelly; Khan, Shahid M.; Janse, Chris J.; S
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /05/2014 EN
Relevância na Pesquisa
26.37%
The prodigious rate at which malaria parasites proliferate during asexual blood-stage replication, midgut sporozoite production, and intrahepatic development creates a substantial requirement for essential nutrients, including fatty acids that likely are necessary for parasite membrane formation. Plasmodium parasites obtain fatty acids either by scavenging from the vertebrate host and mosquito vector or by producing fatty acids de novo via the type two fatty acid biosynthesis pathway (FAS-II). Here, we study the FAS-II pathway in Plasmodium falciparum, the species responsible for the most lethal form of human malaria. Using antibodies, we find that the FAS-II enzyme FabI is expressed in mosquito midgut oocysts and sporozoites as well as liver-stage parasites but not during the blood stages. As expected, FabI colocalizes with the apicoplast-targeted acyl carrier protein, indicating that FabI functions in the apicoplast. We further analyze the FAS-II pathway in Plasmodium falciparum by assessing the functional consequences of deleting fabI and fabB/F. Targeted deletion or disruption of these genes in P. falciparum did not affect asexual blood-stage replication or the generation of midgut oocysts; however, subsequent sporozoite development was abolished. We conclude that the P. falciparum FAS-II pathway is essential for sporozoite development within the midgut oocyst. These findings reveal an important distinction from the rodent Plasmodium parasites P. berghei and P. yoelii...

Increased Endophily by the Malaria Vector Anopheles arabiensis in Southern Zambia and Identification of Digested Blood Meals

Fornadel, Christen M.; Norris, Douglas E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/2008 EN
Relevância na Pesquisa
25.91%
An increase in Anopheles arabiensis showing endophilic behavior was observed in Macha, Zambia during March 2007. To determine whether this shift in resting behavior was accompanied by a change in feeding preference, an attempt was made to calculate the human blood index. However, only 46.2% of blood meals were successfully identified with existing polymerase chain reaction (PCR) diagnostics. This failure was hypothesized to be caused by the limitations of existing methods that are not capable of identifying host source from anophelines resting for extended time periods. Using an assay we developed that allows for the identification of mammalian host DNA out to 60 hours post-feeding, we were able to successfully determine the host source of 94.3% of recovered blood meals. The data show that, although An. arabiensis in Macha experienced a period of higher endophily, the degree of anthropophily and the sporozoite rate in the population remained comparable to the previous malaria season.

The impact of livestock on the abundance, resting behaviour and sporozoite rate of malaria vectors in southern Tanzania

Mayagaya, Valeriana S; Nkwengulila, Gamba; Lyimo, Issa N; Kihonda, Japheti; Mtambala, Hassan; Ngonyani, Hassan; Russell, Tanya L; Ferguson, Heather M
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em 21/01/2015 EN
Relevância na Pesquisa
25.91%

Vectorial capacity, basic reproduction number, force of infection and all that: formal notation to complete and adjust their classical concepts and equations

Massad, Eduardo; Bezerra Coutinho, Francisco Antonio
Fonte: FUNDACO OSWALDO CRUZ; RIO DE JANEIRO, RJ Publicador: FUNDACO OSWALDO CRUZ; RIO DE JANEIRO, RJ
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.33%
A dimensional analysis of the classical equations related to the dynamics of vector-borne infections is presented. It is provided a formal notation to complete the expressions for the Ross' threshold theorem, the Macdonald's basic reproduction "rate" and sporozoite "rate", Garret-Jones' vectorial capacity and Dietz-Molineaux-Thomas' force of infection. The analysis was intended to provide a formal notation that complete the classical equations proposed by these authors.; European Union [282589]; European Union; LIM01 HCFMUSP; LIM01 HCFMUSP; CNPq; CNPq

Vectorial capacity, basic reproduction number, force of infection and all that: formal notation to complete and adjust their classical concepts and equations

Massad,Eduardo; Coutinho,Francisco Antonio Bezerra
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2012 EN
Relevância na Pesquisa
46.33%
A dimensional analysis of the classical equations related to the dynamics of vector-borne infections is presented. It is provided a formal notation to complete the expressions for the Ross' Threshold Theorem, the Macdonald's basic reproduction "rate" and sporozoite "rate", Garret-Jones' vectorial capacity and Dietz-Molineaux-Thomas' force of infection. The analysis was intended to provide a formal notation that complete the classical equations proposed by these authors.

Nigeria Anopheles Vector Database: An Overview of 100 Years' Research

Okorie, Patricia Nkem; McKenzie, F. Ellis; Ademowo, Olusegun George; Bockarie, Moses; Kelly-Hope, Louise
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 05/12/2011 EN
Relevância na Pesquisa
26.16%
Anopheles mosquitoes are important vectors of malaria and lymphatic filariasis (LF), which are major public health diseases in Nigeria. Malaria is caused by infection with a protozoan parasite of the genus Plasmodium and LF by the parasitic worm Wuchereria bancrofti. Updating our knowledge of the Anopheles species is vital in planning and implementing evidence based vector control programs. To present a comprehensive report on the spatial distribution and composition of these vectors, all published data available were collated into a database. Details recorded for each source were the locality, latitude/longitude, time/period of study, species, abundance, sampling/collection methods, morphological and molecular species identification methods, insecticide resistance status, including evidence of the kdr allele, and P. falciparum sporozoite rate and W. bancrofti microfilaria prevalence. This collation resulted in a total of 110 publications, encompassing 484,747 Anopheles mosquitoes in 632 spatially unique descriptions at 142 georeferenced locations being identified across Nigeria from 1900 to 2010. Overall, the highest number of vector species reported included An. gambiae complex (65.2%), An. funestus complex (17.3%), An. gambiae s.s. (6.5%). An. arabiensis (5.0%) and An. funestus s.s. (2.5%)...

Mosquito Species Composition and Plasmodium vivax Infection Rates on Baengnyeong-do (Island), Republic of Korea

Foley, Desmond H.; Klein, Terry A.; Lee, In-Yong; Kim, Myung-Soon; Wilkerson, Richard C.; Harrison, Genelle; Rueda, Leopoldo M.; Kim, Heung Chul
Fonte: The Korean Society for Parasitology Publicador: The Korean Society for Parasitology
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.16%
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.

Statics and dynamics of malaria infection in Anopheles mosquitoes

Smith, David L; Ellis McKenzie, F
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em 04/06/2004 EN
Relevância na Pesquisa
26%
The classic formulae in malaria epidemiology are reviewed that relate entomological parameters to malaria transmission, including mosquito survivorship and age-at-infection, the stability index (S), the human blood index (HBI), proportion of infected mosquitoes, the sporozoite rate, the entomological inoculation rate (EIR), vectorial capacity (C) and the basic reproductive number (R0). The synthesis emphasizes the relationships among classic formulae and reformulates a simple dynamic model for the proportion of infected humans. The classic formulae are related to formulae from cyclical feeding models, and some inconsistencies are noted. The classic formulae are used to to illustrate how malaria control reduces malaria transmission and show that increased mosquito mortality has an effect even larger than was proposed by Macdonald in the 1950's.