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1.
Braz. j. biol ; 83: 1-9, 2023. map, ilus, tab, graf
Article in English | LILACS, VETINDEX | ID: biblio-1468870

ABSTRACT

The present study was conducted to evaluate the diversity, distribution (C) and relative abundance (RA) of the mosquito fauna (Diptera: Culicidae) of Malakand and Dir Lower, Pakistan. Collection of specimens (n = 1087) was made during September 2018 to July 2019 at six different habitats including freshwater bodies, rice fields, animal sheds, indoors, drains and sewage waters. Specimens were collected through light traps, pyrethrum spray, aspirators and nets and subsequently killed, preserved and then arranged in entomological boxes for identification. Three genera were identified namely Culex, Anopheles and Aedes. A total of fourteen species were identified namely: Cx. quinquefasciatus (Say, 1823), An. stephensi (Liston, 1901), Cx. tritaeniorhynchus (Giles, 1901), Ae. vittatus (Bigot, 1861), An. maculatus (Theobald, 1901), An. fluviatilis (James, 1902), Cx. vishnui (Theobald, 1901), Ae. aegypti (Linnaeus, 1762) An. subpictus (Grassi, 1899), An. dthali (Patton, 1905), An. culicifascies (Giles, 1901), An. pallidus (Theobald, 1901), Ae. albopictus (Skuse, 1894) and An. annularis (van der Wulp, 1884). Cx. quinquefasciatus was found constantly distributed in the study area with RA = 16.5% and C = 100%. An. annularis was found as a satellite species, sporadically distributed in the study area having RA = 0.9% and C = 17%. Diversity indices of mosquitoes in the studied habitats were found as, Shannon-Wiener Index (2.415), Simpson Index (9.919), Fisher's Index (2.269) and Margalef's Index (1.859). A statistically significant difference was recorded in mosquito diversity in the six habitats (Kruskal-Wallis, chi-squared, H = 17.5, df = 5, P = 0.003 at α = 0.05). The present study encompasses [...].


O presente estudo foi conduzido para avaliar a diversidade, distribuição (C) e abundância relativa (RA) da fauna de mosquitos (Diptera: Culicidae) de Malakand e Dir Lower, Paquistão. A coleta de espécimes (n = 1087) foi feita durante o período de setembro de 2018 a julho de 2019 em seis habitats diferentes, incluindo corpos d’água, campos de arroz, galpões de animais, ambientes internos, ralos e águas residuais. Os espécimes foram coletados por meio de armadilhas luminosas, spray de piretro, aspiradores e redes e posteriormente mortos, preservados e depois dispostos em caixas entomológicas para identificação. Três gêneros foram identificados, nomeadamente Culex, Anopheles e Aedes. Um total de 14 espécies foi identificado, a saber: Cx. quinquefasciatus (Say, 1823), An. stephensi (Liston, 1901), Cx. tritaeniorhynchus (Giles, 1901), Ae. vittatus (Bigot, 1861), An. maculatus (Theobald, 1901), An. fluviatilis (James, 1902), Cx. vishnui (Theobald, 1901), Ae. aegypti (Linnaeus, 1762), An. subpictus (Grassi, 1899), An. dthali (Patton, 1905), An. culicifascies (Giles, 1901), An. pallidus (Theobald, 1901), Ae. albopictus (Skuse, 1894) e An. annularis (Van der Wulp, 1884). Cx. quinquefasciatus foi encontrado constantemente distribuído na área de estudo com AR = 16,5% e C = 100%. A. annularis foi encontrada como espécie satélite, distribuída esporadicamente na área de estudo com RA = 0,9% e C = 17%. Os índices de diversidade de mosquitos nos habitats estudados foram encontrados como índice de Shannon-Wiener (2,415), índice de Simpson (9,919), índice de Fisher (2,269) e índice de Margalef (1,859). Uma diferença estatisticamente significativa foi registrada na diversidade de mosquitos nos seis habitats (Kruskal-Wallis, qui-quadrado, H = 17,5, df = 5, P = 0,003 em α = 0,05). O presente estudo abrange a fauna de mosquitos de Malakand, Paquistão, com respeito à diversidade, abundância relativa e distribuição em [...].


Subject(s)
Animals , Aedes/classification , Anopheles/classification , Biodiversity , Culex/classification , Culicidae
2.
Mem. Inst. Oswaldo Cruz ; 115: e200043, 2020. tab, graf
Article in English | LILACS, SES-SP | ID: biblio-1135250

ABSTRACT

BACKGROUND The number of malaria cases in Roraima nearly tripled from 2016 to 2018. The capital, Boa Vista, considered a low-risk area for malaria transmission, reported an increasing number of autochthonous and imported cases. OBJECTIVES This study describes a spatial analysis on malaria cases in an urban region of Boa Vista, which sought to identify the autochthonous and imported cases and associated them with Anopheles habitats and the potential risk of local transmission. METHODS In a cross-sectional study at the Polyclinic Cosme e Silva, 520 individuals were interviewed and diagnosed with malaria by microscopic examination. Using a global positional system, the locations of malaria cases by type and origin and the breeding sites of anopheline vectors were mapped and the risk of malaria transmission was evaluated by spatial point pattern analysis. FINDINGS Malaria was detected in 57.5% of the individuals and there was a disproportionate number of imported cases (90.6%) linked to Brazilian coming from gold mining sites in Venezuela and Guyana. MAIN CONCLUSIONS The increase in imported malaria cases circulating in the west region of Boa Vista, where there are positive breeding sites for the main vectors, may represent a potential condition for increased autochthonous malaria transmission in this space.


Subject(s)
Humans , Animals , Male , Female , Adult , Plasmodium/isolation & purification , Travel , Miners/statistics & numerical data , Mosquito Vectors/parasitology , Malaria/diagnosis , Malaria/transmission , Anopheles/parasitology , Plasmodium/classification , Urban Population , Venezuela , Brazil/epidemiology , Cross-Sectional Studies , Geographic Information Systems , Spatial Analysis , Gold , Guyana , Malaria/parasitology , Malaria/epidemiology , Anopheles/classification , Middle Aged
3.
Rev. Soc. Bras. Med. Trop ; 53: e20190211, 2020. tab, graf
Article in English | LILACS | ID: biblio-1057287

ABSTRACT

Abstract INTRODUCTION Anopheles stephensi is the main malaria vector in Southeast Asia. Recently, plant-sourced larvicides are attracting great interests. METHODS: The essential oil was extracted from the leaf of Cinnamomum camphora (L.), and a bioassay was conducted to determine the larvicidal efficacy. The chemical composition of the essential oil was determined by GC-MS analysis. RESULTS: The oil showed strong, dose-dependent larvicidal activities. The onset of larvicidal efficiency was rapid. The LC50 and LC95 were determined as 0.146% and 1.057% at 1 h, 0.031% and 0.237% at 12 h, 0.026% and 0.128% at 24 h, respectively. The oil contains 32 compounds. CONCLUSIONS The essential oil of C. camphora leaf has an excellent larvicidal potential for the control of A. stephensi.


Subject(s)
Animals , Oils, Volatile/pharmacology , Cinnamomum camphora/chemistry , Mosquito Vectors/drug effects , Insecticides/pharmacology , Larva/drug effects , Anopheles/drug effects , Biological Assay , Oils, Volatile/isolation & purification , Mosquito Vectors/classification , Insecticides/isolation & purification , Lethal Dose 50 , Anopheles/classification
4.
Mem. Inst. Oswaldo Cruz ; 114: e180598, 2019. tab, graf
Article in English | LILACS | ID: biblio-1040630

ABSTRACT

Anopheles bellator is a primary malaria vector in the Atlantic Forest. Partial sequences of timeless and Clock genes were used to assess the genetic differentiation of five Brazilian populations, which showed strong population structure (e.g. high F ST values and fixed differences) in all pairwise comparisons between Bahia sample and the others from Paraná, São Paulo and Rio de Janeiro states. Also, the resulting phylogenetic trees clearly grouped the sequences from Bahia in a different cluster with high bootstrap values. Among southern and southeastern populations low levels of genetic differentiation were found suggesting a general stability of the genetic structure.


Subject(s)
Animals , Genetic Variation/genetics , Mosquito Vectors/genetics , Anopheles/genetics , Phylogeny , Brazil , Forests , Sequence Analysis, DNA , Mosquito Vectors/classification , Malaria/transmission , Anopheles/classification
5.
Mem. Inst. Oswaldo Cruz ; 113(2): 87-95, Feb. 2018. tab, graf
Article in English | LILACS | ID: biblio-894897

ABSTRACT

BACKGROUND Studies on malaria vectors in the Pantanal biome, Central Brazil, were conducted more than half a century ago. OBJECTIVES To update anopheline records and assess receptivity and vulnerability to malaria transmission. METHODS Five-day anopheline collections were conducted bimonthly in Salobra, Mato Grosso do Sul state, for one year. Indoors, mosquitoes were collected from their resting places, while in open fields, they were captured using protected human-baited and horse-baited traps near the house and at the Miranda River margin, respectively. Hourly biting activity outdoors was also assessed. Secondary data were collected on the arrival of tourists, economic projects, and malaria cases. FINDINGS A total of 24,894 anophelines belonging to 13 species were caught. The main Brazilian malaria vector Anopheles darlingi was the predominant species, followed by An. triannulatus s.l. Hourly variation in anopheline biting showed three main peaks occurring at sunset, around midnight, and at sunrise, the first and last being the most prominent. The highest density of all species was recorded near the river margin and during the transition period between the rainy and early dry seasons. This coincides with the time of main influx of outsider workers and tourists, whose activities mostly occur in the open fields and frequently start before sunrise and last until sunset. Some of these individuals originate from neighbouring malaria-endemic countries and states, and are likely responsible for the recorded imported and introduced malaria cases. MAIN CONCLUSION Pantanal is a malaria-prone area in Brazil. Surveillance and anopheline control measures must be applied to avoid malaria re-emergence in the region.


Subject(s)
Animals , Oviposition , Malaria/transmission , Anopheles/classification , Anopheles/physiology , Mosquito Vectors , Anopheles/parasitology
6.
Mem. Inst. Oswaldo Cruz ; 113(2): 111-118, Feb. 2018. tab, graf
Article in English | LILACS, SES-SP | ID: biblio-894892

ABSTRACT

BACKGROUND In southeastern Brazil, autochthonous cases of malaria can be found near Atlantic Forest fragments. Because the transmission cycle has not been completely clarified, the behaviour of the possible vectors in those regions must be observed. A study concerning the entomological aspects and natural infection of anophelines (Diptera: Culicidae) captured in the municipalities of the mountainous region of Espírito Santo state was performed in 2004 and 2005. Similarly, between 2014 and 2015, 12 monthly collections were performed at the same area of the study mentioned above. METHODS Center for Disease Control (CDC) light traps with CO2 were set in open areas, at the edge and inside of the forest (canopy and ground), whereas Shannon traps were set on the edge. FINDINGS A total of 1,414 anophelines were collected from 13 species. Anopheles (Kerteszia) cruzii Dyar and Knab remained the most frequently captured species in the CDC traps set in the forest canopy, as well as being the vector with the highest prevalence of Plasmodium vivax/simium infection, according to molecular polymerase chain reaction techniques. CONCLUSIONS P. vivax/simium was found only in abdomens of the mosquitoes of the subgenus Nyssorhynchus, weakening the hypothesis that this subgenus also plays a role in malaria transmission in this specific region.


Subject(s)
Mosquito Vectors/parasitology , Malaria/transmission , Anopheles/classification , Anopheles/parasitology , Brazil , Forests , Population Density , Malaria
7.
Biomédica (Bogotá) ; 37(supl.2): 143-154, jul.-set. 2017. tab, graf
Article in English | LILACS | ID: biblio-888533

ABSTRACT

Abstract Introduction: Mitochondrial DNA has proven its utility for the study of insect evolution. Genes such as cytochrome b (Cytb) and the transfer gene for serine (SertRNA) can be used to compare closely related organisms. Objective: The phylogenetic utility of Cytb-SertRNA-IG1-ND1 was tested for polymorphisms, and secondary structure modeling in SertRNA was done to detect possible cryptic species in Anopheles neivai. Materials and methods: Specimens from Colombia, Guatemala, and the type locality in Panamá were collected and sequenced for specimen comparison based on DNA polymorphisms, and secondary structure modeling for the SertRNA gene. Results: Thirty-six sequences for A. neivai and A. pholidotus were obtained. Conclusions: Polymorphic variants were detected in A. neivai for Cytb-SertRNA-IG1- ND1. Despite this variation in A. neivai, cryptic species could not be detected.


Resumen Introducción. El ADN mitocondrial ha demostrado su utilidad para el estudio de la evolución en los insectos. Existen algunos genes mitocondriales como el citocromo b (Cytb) y el gen de transferencia para el aminoácido serina (SertRNA) que pueden usarse en el diagnóstico de especies estrechamente relacionadas. Objetivo. Explorar la utilidad filogenética de la región Cytb-SertRNA-IG1-ND1 para detectar posibles especies crípticas en Anopheles neivai. Materiales y métodos. Se recolectaron especímenes en Colombia, Guatemala y en la localidad tipo en Panamá, los cuales se secuenciaron y se compararon mediante el polimorfismo de ADN en toda la región y mediante la simulación de estructuras secundarias del gen SertRNA. Resultados. Se obtuvieron las secuencias de especímenes de A. neivai (34) y A. pholidotus (2). Conclusiones. Se detectaron algunos polimorfismos para la regiónCytb-SertRNA-IG1-ND1 en A. neivai, pero no así especies crípticas.


Subject(s)
Animals , DNA, Mitochondrial/genetics , Anopheles/genetics , Panama , Phylogeny , Polymorphism, Genetic , Species Specificity , DNA/analysis , DNA/genetics , RNA, Transfer, Ser/genetics , Genes, Insect , Colombia , Insect Proteins/genetics , Cytochromes b/genetics , Guatemala , Anopheles/classification , Nucleic Acid Conformation
8.
Rev. Soc. Bras. Med. Trop ; 50(3): 388-390, May-June 2017. graf
Article in English | LILACS | ID: biblio-1041408

ABSTRACT

Abstract INTRODUCTION: The muscoid fly Dermatobia hominis causes cutaneous myiases in mammals. Females of this species use a vector to carry their eggs to the host. This note describes Anopheles konderi acting as phoretic vector for D. hominis. METHODS: A female A. konderi carrying D. hominis was collected using light traps in Oriximiná, Pará, Brazil. The A. konderi specimen was identified at morphological and molecular levels. RESULTS: Eight eggs of D. hominis were observed on the Anopheles konderi female. CONCLUSIONS: Anopheles konderi, only the third Anopheles species recorded as a phoretic vector, may be a potential vector of D. hominis.


Subject(s)
Animals , Female , Anopheles/parasitology , Ovum , Symbiosis , Brazil , Diptera/growth & development , Anopheles/classification
9.
Mem. Inst. Oswaldo Cruz ; 111(12): 750-756, Dec. 2016. tab, graf
Article in English | LILACS | ID: biblio-829256

ABSTRACT

Little is known about the Anopheles species of the coastal areas of French Guiana, or their spatiotemporal distribution or environmental determinants. The present study aimed to (1) document the distribution of Anopheles fauna in the coastal area around Cayenne, and (2) investigate the use of remotely sensed land cover data as proxies of Anopheles presence. To characterise the Anopheles fauna, we combined the findings of two entomological surveys that were conducted during the period 2007-2009 and in 2014 at 37 sites. Satellite imagery data were processed to extract land cover variables potentially related to Anopheles ecology. Based on these data, a methodology was formed to estimate a statistical predictive model of the spatial-seasonal variations in the presence of Anopheles in the Cayenne region. Two Anopheles species, known as main malaria vectors in South America, were identified, including the more dominant An. aquasalis near town and rural sites, and An. darlingi only found in inland sites. Furthermore, a cross-validated model of An. aquasalis presence that integrated marsh and forest surface area was extrapolated to generate predictive maps. The present study supports the use of satellite imagery by health authorities for the surveillance of malaria vectors and planning of control strategies.


Subject(s)
Animals , Anopheles/classification , Insect Vectors/classification , French Guiana , Malaria/transmission , Population Density , Satellite Imagery , Seasons , Spatio-Temporal Analysis
10.
Mem. Inst. Oswaldo Cruz ; 111(9): 561-569, Sept. 2016. tab, graf
Article in English | LILACS | ID: lil-794724

ABSTRACT

In French Guiana, malaria vector control and prevention relies on indoor residual spraying and distribution of long lasting insecticidal nets. These measures are based on solid epidemiological evidence but reveal a poor understanding of the vector. The current study investigated the behaviour of both vectors and humans in relation to the ongoing prevention strategies. In 2012 and 2013, Anopheles mosquitoes were sampled outdoors at different seasons and in various time slots. The collected mosquitoes were identified and screened for Plasmodium infection. Data on human behaviour and malaria episodes were obtained from an interview. A total of 3,135 Anopheles mosquitoes were collected, of which Anopheles darlingi was the predominant species (96.2%). For the December 2012-February 2013 period, the Plasmodium vivax infection rate for An. darlingi was 7.8%, and the entomological inoculation rate was 35.7 infective bites per person per three-month span. In spite of high bednet usage (95.7%) in 2012 and 2013, 52.2% and 37.0% of the participants, respectively, had at least one malaria episode. An. darlingi displayed heterogeneous biting behaviour that peaked between 20:30 and 22:30; however, 27.6% of the inhabitants were not yet protected by bednets by 21:30. The use of additional individual and collective protective measures is required to limit exposure to infective mosquito bites and reduce vector densities.


Subject(s)
Humans , Animals , Female , Anopheles/physiology , Insect Bites and Stings , Insect Vectors/physiology , Anopheles/classification , Anopheles/parasitology , Forests , French Guiana , Insect Vectors/classification , Insect Vectors/parasitology , Malaria, Falciparum/transmission , Malaria, Vivax/transmission , Population Density , Seasons , Species Specificity
11.
Mem. Inst. Oswaldo Cruz ; 111(5): 335-346, May 2016. tab, graf
Article in English | LILACS | ID: lil-782048

ABSTRACT

Salivary gland polytene chromosomes of 4th instar Anopheles darlingi Root were examined from multiple locations in the Brazilian Amazon. Minor modifications were made to existing polytene photomaps. These included changes to the breakpoint positions of several previously described paracentric inversions and descriptions of four new paracentric inversions, two on the right arm of chromosome 3 and two on the left arm of chromosome 3 that were found in multiple locations. A total of 18 inversions on the X (n = 1) chromosome, chromosome 2 (n = 7) and 3 (n = 11) were scored for 83 individuals from Manaus, Macapá and Porto Velho municipalities. The frequency of 2Ra inversion karyotypes in Manaus shows significant deficiency of heterozygotes (p < 0.0009). No significant linkage disequilibrium was found between inversions on chromosome 2 and 3. We hypothesize that at least two sympatric subpopulations exist within the An. darlingi population at Manaus based on inversion frequencies.


Subject(s)
Animals , Anopheles/genetics , Chromosome Inversion/genetics , Insect Vectors/genetics , Polytene Chromosomes/genetics , Salivary Glands , Anopheles/classification , Brazil , Chromosome Mapping , Insect Vectors/classification
12.
Rev. Inst. Med. Trop. Säo Paulo ; 57(3): 263-267, May-Jun/2015. tab, graf
Article in English | LILACS | ID: lil-752600

ABSTRACT

We conducted a survey of the malaria vectors in an area where a power line had been constructed, between the municipalities of Porto Velho and Rio Branco, in the states of Rondônia and Acre, respectively. The present paper relates to the results of the survey of Anopheles fauna conducted in the state of Rondônia. Mosquito field collections were performed in six villages along the federal highway BR 364 in the municipality of Porto Velho, namely Porto Velho, Jaci Paraná, Mutum Paraná, Vila Abunã, Vista Alegre do Abunã, and Extrema. Mosquito captures were performed at three distinct sites in each locality during the months of February, July, and October 2011 using a protected human-landing catch method; outdoor and indoor captures were conducted simultaneously at each site for six hours. In the six sampled areas, we captured 2,185 mosquitoes belonging to seven Anopheles species. Of these specimens, 95.1% consisted of Anopheles darlingi, 1.8% An. triannulatus l.s., 1.7% An. deaneorum, 0.8% An. konderi l.s., 0.4 An. braziliensis, 0.1% An. albitarsis l.s., and 0.1% An. benarrochi. An. darlingi was the only species found in all localities; the remaining species occurred in sites with specific characteristics.


Foi realizado levantamento de vetores de malária na área que compreende a construção da linha de transmissão entre os municípios de Porto Velho e Rio Branco, estados de Rondônia e Acre, respectivamente. Os dados aqui apresentados mostram os resultados do levantamento da fauna dos Anopheles realizado em Rondônia. As capturas foram realizadas no município de Porto Velho em seis aglomerados populacionais ao longo da rodovia federal BR 364, denominados Porto Velho, Jaci Paraná, Mutum Paraná, Vila Abunã, Vista Alegre do Abunã e Extrema. As capturas ocorreram em três diferentes pontos de cada uma das localidades nos meses de fevereiro, julho e outubro de 2011, seguindo a metodologia de coleta por atração humana protegida em dois ambientes, sendo no intradomicílio e no peridomicílio simultaneamente com duração de seis horas. Nas áreas amostradas foram capturados 2.185 anofelinos pertencentes a sete espécies de Anopheles sp. dos quais 95,1% foram identificados como Anophels darlingi, 1,8% An. triannulatus l.s., 1,7% An. deaneorum, 0,8% An. konderi l.s., 0,4 An. braziliensis, 0,1% An. albitarsis l.s., e 0,1% An. benarrochi. Anopheles darlingi foi a única espécie amostrada em todas as localidades enquanto as demais espécies, ocorreram em locais com características singulares.


Subject(s)
Animals , Humans , Anopheles/classification , Insect Vectors/classification , Brazil , Malaria/transmission , Population Density , Rural Population , Seasons
13.
Mem. Inst. Oswaldo Cruz ; 109(8): 1021-1029, 12/2014. tab, graf
Article in English | LILACS | ID: lil-732604

ABSTRACT

Traps are widely employed for sampling and monitoring mosquito populations for surveillance, ecological and fauna studies. Considering the importance of assessing other technologies for sampling mosquitoes, we addressed the effectiveness of Mosquito Magnet® Independence (MMI) in comparison with those of the CDC trap with CO2 and Lurex3® (CDC-A) and the CDC light trap (CDC-LT). Field collections were performed in a rural area within the Atlantic Forest biome, southeastern state of São Paulo, Brazil. The MMI sampled 53.84% of the total number of mosquitoes, the CDC-A (26.43%) and CDC-LT (19.73%). Results of the Pearson chi-squared test (χ2) showed a positive association between CDC-LT and species of Culicini and Uranotaeniini tribes. Additionally, our results suggested a positive association between CDC-A and representatives of the Culicini and Aedini tribes, whereas the MMI was positively associated with the Mansoniini and Sabethini as well as with Anophelinae species. The MMI sampled a greater proportion (78.27%) of individuals of Anopheles than either the CDC-LT (0.82%) or the CDC-A traps (20.91%). Results of the present study showed that MMI performed better than CDC-LT or CDC-A in sampling mosquitoes in large numbers, medically important species and assessing diversity parameters in rural southeastern Atlantic Forest.


Subject(s)
Animals , Anopheles/classification , Insect Vectors/classification , Mosquito Control/instrumentation , Rainforest , Tropical Climate , Biodiversity , Brazil , Culex , Culicidae/classification , Ecosystem , Mosquito Control/methods , Ochlerotatus/classification , Population Density , Public Health , Rural Health
14.
Mem. Inst. Oswaldo Cruz ; 109(7): 952-956, 11/2014. tab, graf
Article in English | LILACS | ID: lil-728802

ABSTRACT

Malaria in La Guajira, the most northern state of Colombia, shows two different epidemiological patterns. Malaria is endemic in the municipality of Dibulla whereas in Riohacha it is characterised by sporadic outbreaks. This study aimed to establish whether differences in transmission patterns could be attributed to different vector species. The most abundant adult female species were Anopheles aquasalis, exclusive to Riohacha, and Anopheles darlingi, restricted to Dibulla. Anopheles mosquitoes were identified using morphology and the molecular markers internal transcribed spacer 2 and cytochrome c oxidase I. All specimens (n = 1,393) were tested by ELISA to determine natural infection rates with Plasmodium falciparum and Plasmodium vivax. An. darlingi was positive for P. vivax 210, with an infection rate of 0.355% and an entomological inoculation rate of 15.87 infective bites/person/year. Anopheles albimanus larvae were the most common species in Riohacha, found in temporary swamps; in contrast, in Dibulla An. darlingi were detected mainly in permanent streams. Distinctive species composition and larval habitats in each municipality may explain the differences in Plasmodium transmission and suggest different local strategies should be used for vector control.


Subject(s)
Humans , Animals , Female , Anopheles/classification , Insect Vectors/classification , Malaria/transmission , Plasmodium , Anopheles/anatomy & histology , Biomarkers , Cities , Colombia , DNA, Intergenic , Enzyme-Linked Immunosorbent Assay , Geography , Malaria/parasitology , Species Specificity
15.
Rev. Inst. Med. Trop. Säo Paulo ; 56(5): 403-409, Sep-Oct/2014. tab, graf
Article in English | LILACS, SES-SP | ID: lil-722331

ABSTRACT

Anopheles (Kerteszia) cruzii has been implicated as the primary vector of human and simian malarias out of the Brazilian Amazon and specifically in the Atlantic Forest regions. The presence of asymptomatic human cases, parasite-positive wild monkeys and the similarity between the parasites infecting them support the discussion whether these infections can be considered as a zoonosis. Although many aspects of the biology of An. cruzii have already been addressed, studies conducted during outbreaks of malaria transmission, aiming at the analysis of blood feeding and infectivity, are missing in the Atlantic Forest. This study was conducted in the location of Palestina, Juquitiba, where annually the majority of autochthonous human cases are notified in the Atlantic Forest of the state of São Paulo. Peridomiciliary sites were selected for collection of mosquitoes in a perimeter of up to 100 m around the residences of human malaria cases. The mosquitoes were analyzed with the purpose of molecular identification of blood-meal sources and to examine the prevalence of Plasmodium. A total of 13,441 females of An. (Ker.) cruzii were collected. The minimum infection rate was calculated at 0.03% and 0.01%, respectively, for P. vivax and P. malariae and only human blood was detected in the blood-fed mosquitoes analyzed. This data reinforce the hypothesis that asymptomatic human carriers are the main source of anopheline infection in the peridomiciliary area, making the probability of zoonotic transmission less likely to happen.


Anopheles (Kerteszia) cruzii é o vetor primário das malárias humana e simiana fora da Amazônia Brasileira e especificamente nas regiões de Mata Atlântica. A presença de casos humanos assintomáticos, macacos silvestres positivos para Plasmodium e a similaridade entre os parasitas que os infectam suportam a discussão se essas infecções podem ser consideradas como zoonoses. Embora muitos aspectos da biologia de An. cruzii já tenham sido abordados, estudos conduzidos durante surtos de transmissão de malária, visando a análise de repasto sanguíneo e infectividade, são ausentes na Mata Atlântica. Este estudo foi conduzido na localidade de Palestina, Juquitiba, Mata Atlântica do Estado de São Paulo, onde anualmente a maioria dos casos humanos autóctones é notificada. Locais em peridomicílio foram selecionados para coleta de mosquitos em um perímetro de até 100 m em torno das residências de casos humanos de malária e da floresta circundante. Os mosquitos foram analisados com o objetivo de identificação molecular das fontes de repasto sanguíneo e para examinar a prevalência de Plasmodium. Um total de 13.441 fêmeas de An. (Ker.) cruzii foi coletado. A taxa de infecção mínima foi calculada a 0,03% e 0,01%, respectivamente, para P. vivax e P. malariae e somente sangue humano foi detectado nos mosquitos analisados que se alimentaram com sangue. Nossos dados reforçam a hipótese de que os portadores humanos assintomáticos são a principal fonte de infecção para os anofelinos na área do peridomicílio, tornando a transmissão zoonótica improvável.


Subject(s)
Animals , Female , Humans , Anopheles/physiology , Asymptomatic Infections , Feeding Behavior/physiology , Insect Vectors/physiology , Malaria/transmission , Anopheles/classification , Blood , Brazil , Insect Vectors/classification , Population Density , Seasons , Trees
16.
Mem. Inst. Oswaldo Cruz ; 109(5): 618-633, 19/08/2014. tab, graf
Article in English | LILACS, SES-SP | ID: lil-720414

ABSTRACT

Brazil, a country of continental proportions, presents three profiles of malaria transmission. The first and most important numerically, occurs inside the Amazon. The Amazon accounts for approximately 60% of the nation’s territory and approximately 13% of the Brazilian population. This region hosts 99.5% of the nation’s malaria cases, which are predominantly caused by Plasmodium vivax (i.e., 82% of cases in 2013). The second involves imported malaria, which corresponds to malaria cases acquired outside the region where the individuals live or the diagnosis was made. These cases are imported from endemic regions of Brazil (i.e., the Amazon) or from other countries in South and Central America, Africa and Asia. Imported malaria comprised 89% of the cases found outside the area of active transmission in Brazil in 2013. These cases highlight an important question with respect to both therapeutic and epidemiological issues because patients, especially those with falciparum malaria, arriving in a region where the health professionals may not have experience with the clinical manifestations of malaria and its diagnosis could suffer dramatic consequences associated with a potential delay in treatment. Additionally, because the Anopheles vectors exist in most of the country, even a single case of malaria, if not diagnosed and treated immediately, may result in introduced cases, causing outbreaks and even introducing or reintroducing the disease to a non-endemic, receptive region. Cases introduced outside the Amazon usually occur in areas in which malaria was formerly endemic and are transmitted by competent vectors belonging to the subgenus Nyssorhynchus (i.e., Anopheles darlingi, Anopheles aquasalis and species of the Albitarsis complex). The third type of transmission accounts for only 0.05% of all cases and is caused by autochthonous malaria in the Atlantic Forest, located primarily along the southeastern Atlantic Coast. They are caused by parasites that seem to be (or to be very close to) P. vivax and, in a less extent, by Plasmodium malariae and it is transmitted by the bromeliad mosquito Anopheles (Kerteszia) cruzii. This paper deals mainly with the two profiles of malaria found outside the Amazon: the imported and ensuing introduced cases and the autochthonous cases. We also provide an update regarding the situation in Brazil and the Brazilian endemic Amazon.


Subject(s)
Animals , Humans , Anopheles/classification , Endemic Diseases , Insect Vectors/classification , Malaria, Falciparum/epidemiology , Malaria, Vivax/epidemiology , Travel , Brazil/epidemiology , Geography, Medical , Malaria, Falciparum/transmission , Malaria, Vivax/transmission
17.
Mem. Inst. Oswaldo Cruz ; 109(5): 685-705, 19/08/2014. tab, graf
Article in English | LILACS | ID: lil-720418

ABSTRACT

Distribution, abundance, feeding behaviour, host preference, parity status and human-biting and infection rates are among the medical entomological parameters evaluated when determining the vector capacity of mosquito species. To evaluate these parameters, mosquitoes must be collected using an appropriate method. Malaria is primarily transmitted by anthropophilic and synanthropic anophelines. Thus, collection methods must result in the identification of the anthropophilic species and efficiently evaluate the parameters involved in malaria transmission dynamics. Consequently, human landing catches would be the most appropriate method if not for their inherent risk. The choice of alternative anopheline collection methods, such as traps, must consider their effectiveness in reproducing the efficiency of human attraction. Collection methods lure mosquitoes by using a mixture of olfactory, visual and thermal cues. Here, we reviewed, classified and compared the efficiency of anopheline collection methods, with an emphasis on Neotropical anthropophilic species, especially Anopheles darlingi, in distinct malaria epidemiological conditions in Brazil.


Subject(s)
Animals , Humans , Anopheles/classification , Insect Vectors/classification , Mosquito Control/instrumentation , Brazil , Malaria/transmission , Mosquito Control/methods , Seasons
18.
Mem. Inst. Oswaldo Cruz ; 109(5): 662-667, 19/08/2014. graf
Article in English | LILACS | ID: lil-720425

ABSTRACT

Plasmodium falciparum originated in Africa, dispersed around the world as a result of human migration and had to adapt to several different indigenous anopheline mosquitoes. Anophelines from the New World are evolutionary distant form African ones and this probably resulted in a more stringent selection of Plasmodium as it adapted to these vectors. It is thought that Plasmodium has been genetically selected by some anopheline species through unknown mechanisms. The mosquito immune system can greatly limit infection and P. falciparum evolved a strategy to evade these responses, at least in part mediated by Pfs47, a highly polymorphic gene. We propose that adaptation of P. falciparum to new vectors may require evasion of their immune system. Parasites with a Pfs47 haplotype compatible with the indigenous mosquito vector would be able to survive and be transmitted. The mosquito antiplasmodial response could be an important determinant of P. falciparum population structure and could affect malaria transmission in the Americas.


Subject(s)
Animals , Humans , Anopheles/parasitology , Insect Vectors/parasitology , Plasmodium falciparum/physiology , Adaptation, Physiological/genetics , Adaptation, Physiological/immunology , Anopheles/classification , Anopheles/immunology , Host-Parasite Interactions/genetics , Immune Evasion , Insect Vectors/classification , Membrane Glycoproteins/genetics , Plasmodium falciparum/genetics , Protozoan Proteins/genetics
19.
Mem. Inst. Oswaldo Cruz ; 109(5): 644-661, 19/08/2014. graf
Article in English | LILACS | ID: lil-720429

ABSTRACT

Nearly one million people are killed every year by the malaria parasite Plasmodium. Although the disease-causing forms of the parasite exist only in the human blood, mosquitoes of the genus Anopheles are the obligate vector for transmission. Here, we review the parasite life cycle in the vector and highlight the human and mosquito contributions that limit malaria parasite development in the mosquito host. We address parasite killing in its mosquito host and bottlenecks in parasite numbers that might guide intervention strategies to prevent transmission.


Subject(s)
Animals , Humans , Anopheles/parasitology , Insect Vectors/parasitology , Life Cycle Stages/physiology , Plasmodium/growth & development , Anopheles/classification , Host-Parasite Interactions/physiology , Insect Vectors/classification , Malaria/transmission , Plasmodium/physiology
20.
Mem. Inst. Oswaldo Cruz ; 109(4): 473-479, 03/07/2014. tab, graf
Article in English | LILACS | ID: lil-716299

ABSTRACT

Since 1984, Anopheles (Kerteszia) lepidotus has been considered a mosquito species that is involved in the transmission of malaria in Colombia, after having been incriminated as such with epidemiological evidence from a malaria outbreak in Cunday-Villarrica, Tolima. Subsequent morphological analyses of females captured in the same place and at the time of the outbreak showed that the species responsible for the transmission was not An. lepidotus, but rather Anopheles pholidotus. However, the associated morphological stages and DNA sequences of An. pholidotus from the foci of Cunday-Villarrica had not been analysed. Using samples that were caught recently from the outbreak region, the purpose of this study was to provide updated and additional information by analysing the morphology of female mosquitoes, the genitalia of male mosquitoes and fourth instar larvae of An. pholidotus, which was confirmed with DNA sequences of cytochrome oxidase I and rDNA internal transcribed spacer. A total of 1,596 adult females were collected in addition to 37 larval collections in bromeliads. Furthermore, 141 adult females, which were captured from the same area in the years 1981-1982, were analysed morphologically. Ninety-five DNA sequences were analysed for this study. Morphological and molecular analyses showed that the species present in this region corresponds to An. pholidotus. Given the absence of An. lepidotus, even in recent years, we consider that the species of mosquitoes that was previously incriminated as the malaria vector during the outbreak was indeed An. pholidotus, thus ending the controversy.


Subject(s)
Animals , Female , Male , Anopheles/anatomy & histology , Anopheles/genetics , Genitalia, Male/anatomy & histology , Anopheles/classification , Base Sequence , Colombia , DNA, Mitochondrial/genetics , DNA, Ribosomal Spacer/genetics , Larva/anatomy & histology , Larva/classification , Larva/genetics , Molecular Sequence Data , Phylogeny
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