scholarly journals Genetic heterogeneity in Anopheles darlingi related to biting behavior in western Amazon

2018 ◽  
Author(s):  
Melina Campos ◽  
Diego Peres Alonso ◽  
Jan E. Conn ◽  
Joseph M. Vinetz ◽  
Kevin J. Emerson ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Malaria Vector ◽  
Amazon Basin ◽  
Genetic Basis ◽  
Control Strategies ◽  
Blood Feeding ◽  
Genetic Component ◽  
Anopheles Darlingi ◽  
Genetic Diversity And Structure ◽  
Biting Behavior

ABSTRACTIn the Amazon Basin, Anopheles (Nyssorhynchus) darlingi is the most aggressive and effective malaria vector. In endemic areas, behavioral aspects of anopheline species such as host preference, biting time and resting location after a blood meal have a key impact on malaria transmission dynamics and transmission control strategies. An. darlingi present a variety in behavior throughout its broad distribution including blood feeding related. To investigate the genetic basis of its biting behaviors, host-seeking An. darlingi were collected in two settlements (Granada and Remansinho) in Acre, Brazil. Mosquitoes were classified by captured location (indoors or outdoors) and time (dusk or dawn). Genome-wide SNPs were used to assess the degree of genetic diversity and structure in these groups. There was evidence of genetic component of biting behavior regarding both location and time in this species. This study supports that An. darlingi blood-feeding behavior has a genetic component. Additional ecological and genomic studies may help to understand the genetic basis of mosquito behavior and address appropriate surveillance and vector control.Author SummaryMalaria is a disease caused by parasite of the genus Plasmodium and is transmitted by mosquitoes of the genus Anopheles. In the Amazon Basin, the main malaria vector is Anopheles darlingi, which is present in high densities in this region. Egg development requires that females of this mosquito seek hosts for blood meals. Anopheles females blood feeding may occur indoor or outdoor the houses and typically from the sunset to dawn. Anopheles darlingi in particular present great variability regarding its behaviour, presenting variety of peak biting times and patterns. This work shows that there is a genetic component that partially explains these two behaviors: location of the blood meal (inside or outside the houses) and time of feeding. Single nucleotide polymorphisms (SNPs) scattered throughout the genome of Anopheles darlingi showed genetic diversity and structure in these groups. A comprehensive understanding of the genetic basis for mosquito behaviour may support innovative vector surveillance and control strategies.

scholarly journals Genetic diversity and population structure of Plasmodium falciparum in Nigeria: insights from microsatellite loci analysis

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Fehintola V. Ajogbasile ◽  
Adeyemi T. Kayode ◽  
Paul E. Oluniyi ◽  
Kazeem O. Akano ◽  
Jessica N. Uwanibe ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Plasmodium Falciparum ◽  
Population Structure ◽  
Microsatellite Loci ◽  
Control Strategies ◽  
Population Diversity ◽  
Parasite Population ◽  
Nested Polymerase Chain Reaction ◽  
Public Health Burden ◽  
Genetic Diversity And Structure

Abstract Background Malaria remains a public health burden especially in Nigeria. To develop new malaria control and elimination strategies or refine existing ones, understanding parasite population diversity and transmission patterns is crucial. Methods In this study, characterization of the parasite diversity and structure of Plasmodium falciparum isolates from 633 dried blood spot samples in Nigeria was carried out using 12 microsatellite loci of P. falciparum. These microsatellite loci were amplified via semi-nested polymerase chain reaction (PCR) and fragments were analysed using population genetic tools. Results Estimates of parasite genetic diversity, such as mean number of different alleles (13.52), effective alleles (7.13), allelic richness (11.15) and expected heterozygosity (0.804), were high. Overall linkage disequilibrium was weak (0.006, P < 0.001). Parasite population structure was low (Fst: 0.008–0.105, AMOVA: 0.039). Conclusion The high level of parasite genetic diversity and low population structuring in this study suggests that parasite populations circulating in Nigeria are homogenous. However, higher resolution methods, such as the 24 SNP barcode and whole genome sequencing, may capture more specific parasite genetic signatures circulating in the country. The results obtained can be used as a baseline for parasite genetic diversity and structure, aiding in the formulation of appropriate therapeutic and control strategies in Nigeria.

scholarly journals The genetic basis of host choice and resting behavior in the major African malaria vector, Anopheles arabiensis

2016 ◽  
Author(s):  
Bradley J Main ◽  
Yoosook Lee ◽  
Heather M Ferguson ◽  
Katharina S Kreppel ◽  
Anicet Kihonda ◽  
...  
Keyword(s):  
Malaria Vector ◽  
Anopheles Arabiensis ◽  
Genetic Basis ◽  
Host Choice ◽  
Genetic Component ◽  
Insecticide Treated Nets ◽  
Genome Wide ◽  
Kilombero Valley ◽  
Resting Behavior ◽  
Standard Arrangement

AbstractMalaria transmission is dependent on the propensity of Anopheles mosquitoes to bitehumans (anthropophily) instead of other dead end hosts. Recent increases in the usage of Long Lasting Insecticide Treated Nets (LLINs) in Africa have been associated with reductions in highly anthropophilic vectors such as Anopheles gambiae s.s.,leaving less anthropophilic species such as Anopheles arabiensis as the most prominent remaining source of transmission in many settings. An.arabiensis is more of a generalist in terms of its host choice and resting behavior, which may be due to phenotypic plasticity and/or segregating allelic variation. To investigate the potential genetic basis of host choice and resting behavior in An. arabiensis we performed a genome-wide association study on host choice (human-or cattle-fed) and resting position (collected indoors or outdoors) in the Kilombero Valley, Tanzania. This represents the first genomic/molecular analysis of host choice and resting behavior in a malaria vector. We identified a total of 4,820,851 SNPs, which were used to conduct the first genome-wide estimates of 'SNP heritability' for host choice and resting behavior in this species. A genetic component was detected for host choice (human vs cow fed; permuted P = 0.002), but there was no evidence of a genetic component for resting behavior (indoors versus outside; permuted P = 0.465). A principal component analysis (PCA) segregated individuals based on genomic variation into three groups which are characterized by differences at the 2Rb and/or 3Ra paracentromeric chromosome inversions. There was a non-random distribution of cattle-fed mosquitoes between the PCA clusters, suggesting that alleles linked to the 2Rb and/or 3Ra inversions may influence host choice. Using a novel inversion genotyping assay, we detected a significant enrichment of the standard arrangement (non-inverted) of 3Ra among cattle-fed mosquitoes (N=129) versus all non-cattle-fed individuals (N=234; १2, p=0.007). Thus, tracking the frequency of the 3Ra in An. arabiensis populations is important, especially in relation to the emergence of behavioral avoidance(e.g. shifting toward cattle-feeding) in some populations. A better understanding of the genetic basis for host choice in An. arabiensis may also open avenues for novel vector control strategies based on introducing genes for zoophily into wild mosquito populations.Author summaryMalaria transmission is driven by the propensity for mosquito vectors to bite people, whilst its control depends on the tendency of mosquitoes to bite and rest in places where they will come into contact with insecticides. In many parts of Africa, Anopheles arabiensis is now the only remaining vec 63 tor in areas where coverage with Long Lasting Insecticide Treated Nets is high. We sought to assess the potential for An. arabiensis to adapt its behavior to avoid control measures by investigating the genetic basis for its host choice and resting behavior. Blood fed An. arabiensis were collected resting indoors and outdoors in the Kilombero Valley, Tanzania. We sequenced a total of 48 genomes representing 4 phenotypes (human or cow fed, resting in or outdoors) and tested for a genetic basis for each phenotype. Genomic analysis followed up by application of a novel molecular karyotyping assay revealed a relationship between An. arabiensis that fed on cattle and the standard arrangement of the 3Ra inversion. This indicates that the host choice behavior of An. arabiensis has has a substantial genetic component. Validation with controlled host preference assays comparing individuals with the standard and inverted arrangement of 3Ra is still needed.

scholarly journals Genetic diversity of Nyssorhynchus (Anopheles) darlingi related to biting behavior in western Amazon

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Melina Campos ◽  
Diego Peres Alonso ◽  
Jan E. Conn ◽  
Joseph M. Vinetz ◽  
Kevin J. Emerson ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Anopheles Darlingi ◽  
Biting Behavior

Field Efficacy of VectoMax FG and VectoLex CG Biological Larvicides for Malaria Vector Control in Northwestern Brazil

2019 ◽  
Vol 57 (3) ◽  
pp. 942-946 ◽  
Author(s):  
Pablo S Fontoura ◽  
Anderson S da Costa ◽  
Francismar S Ribeiro ◽  
Marcílio S Ferreira ◽  
Marcia C Castro ◽  
...  
Keyword(s):  
Malaria Vector ◽  
Amazon Basin ◽  
Larval Density ◽  
Indoor Residual Spraying ◽  
Residual Effect ◽  
Fish Farming ◽  
Malaria Vector Control ◽  
Fish Ponds ◽  
Anopheles Darlingi ◽  
Larval Habitats

Abstract Despite historical and contemporary evidence of its effectiveness, larval source management with insecticides remains little used by most malaria control programs worldwide. Here we show that environmentally safe biological larvicides under field conditions can significantly reduce anopheline larval density in fish farming ponds that have became major larval habitats across the Amazon Basin. Importantly, the primary local malaria vector, Anopheles darlingi Root (Diptera: Culicidae), feeds and rests predominantly outdoors, being little affected by interventions such as long-lasting insecticidal bed net distribution and indoor residual spraying. We found &gt;95% reduction in late-instar density up to 7 d after the first application of VectoMax FG or VectoLex CG (both from Valent BioSciences), and up to 21 d after larvicide reapplication in fish ponds (n = 20) situated in the main residual malaria pocket of Brazil, irrespective of the formulation or dosage (10 or 20 kg/ha) used. These results are consistent with a substantial residual effect upon retreatment and support the use of biological larvicides to reduce the density of anopheline larvae in this and similar settings across the Amazon where larval habitats are readily identified and accessible.

scholarly journals Genetic diversity and structure of Ganoderma boninense isolates from oil palm and other plantation crops

2020 ◽  
Vol 21 (2) ◽  
Author(s):  
AGUSTIAMAN PURBA ◽  
RAHMAH HAYATI ◽  
LOLLIE A.P. PUTRI ◽  
DIANA CHALIL ◽  
INDRA SYAHPUTRA ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Oil Palm ◽  
Elaeis Guineensis ◽  
Control Strategies ◽  
Cocos Nucifera ◽  
Ganoderma Boninense ◽  
Success Rates ◽  
Genetic Diversity And Structure ◽  
Distinct Individual ◽  
Plantation Crops

Abstract. Purba A, Hayati R, Putri LAP, Chalil D, Afandi D, Syahputra I, Basyuni M. 2020. Genetic diversity and structure of Ganoderma boninense isolates from oil palm and other plantation crops. Biodiversitas 21: 451-456. Oil palm is an economically important plant, which one of the most important sources of vegetable oil in the world. However, oil palm plantation and other crops face the treat basal stem rot (BSR) disease by Ganoderma boninense. A study on genetic diversity and structure of G. boninense is therefore needed in order to formulate improved control strategies for this disease. This work aimed to analyze the genetic diversity and structure of the G. boninense isolates derived from different hosts, 131 oil palm (Elaeis guineensis), six rubber (Hevea brasiliensis), three coconuts (Cocos nucifera), and three lontar palm (Borassus flabellifer). Genetic diversity and population structure of G. boninense isolates were investigated using six SSR markers with GenAlex 6.502 software. Results showed that several microsatellite loci indicated specific primary success rates, such as KT124402, KT124399, and KT124394, depicting high polymorphism content (>75%). This result suggested that these markers were equally effective in determining the polymorphisms of G. boninense isolates. A hierarchical analysis of molecular variance (AMOVA) revealed that genetic diversity mostly found among individuals within a population (88%), then among populations (8%), and within individuals (4%).. Phylogeny analysis showed two clusters of Ganoderma isolates. which was considered variation as dissimilar across with origin. The present study indicated that G. boninense from oil palm was predominantly comprised of a genetically distinct individual.

scholarly journals Genome-wide Investigation of Genetic Diversity in the Poultry Red Mite, Dermanyssus Gallinae, From European Farms Utilising a NGS-Multiplex Platform

2021 ◽  
Author(s):  
Eleanor Karp-Tatham ◽  
Dong Xia ◽  
Alasdair J Nisbet ◽  
Teresa Letra Mateus ◽  
Fiona M. Tomley ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Control Strategies ◽  
Variant Calling ◽  
Blood Feeding ◽  
Snp Markers ◽  
Current Control ◽  
Egg Laying ◽  
Alternative Methods ◽  
Dermanyssus Gallinae ◽  
Poultry Red Mite

Abstract The poultry red mite (Dermanyssus gallinae), an obligatory blood feeding ectoparasite, is primarily associated with egg laying hens where it is estimated to cause losses of ~€230 million per annum from European farmers. Current control strategies, including the use of acaricidal chemicals and desiccant dusts, are often ineffective and there is widespread resistance to acaricides across Europe. Alternative methods to control D. gallinae are urgently required and strategies include development of recombinant subunit vaccines and discovery of new potential acaricides. These strategies will benefit hugely from knowledge of the extent and rates of occurrence of genetic diversity within D. gallinae populations. In this study, genetic diversity of mites harvested from the UK and from sites across mainland Europe was studied at inter- and intra-farm levels. To achieve this, the genome analysis toolkit (GATK) best practices pipeline for single nucleotide polymorphism (SNP) and insertion/deletion variant calling was modified to be self-validating and used to identify 32,599 D. gallinae SNPs by comparing transcriptomic sequences (derived from mites harvested in Germany, Schicht et al.) with a D. gallinae genome assembly (derived from mites harvested in Scotland, Burgess et al.). Dermanyssus gallinae populations were sampled from 22 UK farms and 57 farms from 15 countries in mainland Europe. Analysis of 144 high-quality SNP markers across 117 pooled D. gallinae samples showed high spatial genetic diversity with significant linkage disequilibrium. Revisiting a subset of farms revealed notable temporal changes in genetic diversity.

scholarly journals Molecular detection and genetic diversity of Leucocytozoon sabrazesi in chickens in Thailand

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Runglawan Chawengkirttikul ◽  
Witchuta Junsiri ◽  
Amaya Watthanadirek ◽  
Napassorn Poolsawat ◽  
Sutthida Minsakorn ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Egg Production ◽  
Control Strategies ◽  
Amino Acid Sequences ◽  
Economic Losses ◽  
Nested Polymerase Chain Reaction ◽  
Blood Samples ◽  
Tropical Regions ◽  
Vaccination Programs ◽  
High Entropy

AbstractLeucocytozoon sabrazesi is the intracellular protozoa of leucocytozoonosis, which is transmitted by the insect vectors and affects chickens in most subtropical and tropical regions of the globe, except South America, and causing enormous economic losses due to decreasing meat yield and egg production. In this study, L. sabrazesi gametocytes have been observed in the blood smears, and molecular methods have been used to analyse the occurrence and genetic diversity of L. sabrazesi in blood samples from 313 chickens raised in northern, western and southern parts of Thailand. The nested polymerase chain reaction (nested PCR) assay based on the cytb gene revealed that 80.51% (252/313) chickens were positive of L. sabrazesi. The phylogenetic analysis indicated that L. sabrazesi cytb gene is conserved in Thailand, showed 2 clades and 2 subclades with similarity ranged from 89.5 to 100%. The diversity analysis showed 13 and 18 haplotypes of the sequences from Thailand and from other countries, respectively. The entropy analyses of nucleic acid sequences showed 26 high entropy peaks with values ranging from 0.24493 to 1.21056, while those of amino acid sequences exhibited 5 high entropy peaks with values ranging from 0.39267 to 0.97012. The results; therefore, indicate a high molecular occurrence of L. sabrazesi in chicken blood samples with the associated factors that is statistically significant (p < 0.05). Hence, our results could be used to improve the immunodiagnostic methods and to find appropriate preventive control strategies or vaccination programs against leucocytozoonosis in order to mitigate or eliminate the harmful impact of this infection on chicken industry.

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