Last data update: May 20, 2024. (Total: 46824 publications since 2009)
Records 1-11 (of 11 Records) |
Query Trace: Lawrence GG [original query] |
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Novel Wolbachia strains in Anopheles malaria vectors from Sub-Saharan Africa (preprint)
Jeffries CL , Lawrence GG , Golovko G , Kristan M , Orsborne J , Spence K , Hurn E , Bandibabone J , Tantely LM , Raharimalala FN , Keita K , Camara D , Barry Y , Wat'senga F , Manzambi EZ , Afrane YA , Mohammed AR , Abeku TA , Hedge S , Khanipov K , Pimenova M , Fofanov Y , Boyer S , Irish SR , Hughes GL , Walker T . bioRxiv 2018 338434 Anopheles (An.) mosquitoes contain bacteria that can influence Plasmodium parasites. Wolbachia, a common insect endosymbiont, has historically been considered absent from Anopheles but has recently been found in An. gambiae populations. Here, we assessed a range of Anopheles species from five malaria-endemic countries for Wolbachia and Plasmodium infection. Strikingly, we found Wolbachia infections in An. coluzzii, An. gambiae s.s, An. arabiensis, An. moucheti and An. species ‘A’ increasing the number of Anopheles species known to be naturally infected by this endosymbiont. Molecular analysis suggests the presence of phylogenetically diverse novel strains, while qPCR and 16S rRNA sequencing indicates that Wolbachia is the dominant member of the microbiota in An. moucheti and An. species ‘A’. We found no evidence of Wolbachia/Asaia co-infections, and presence of these endosymbionts did not have significant effects on malaria prevalence. We discuss the importance of novel Wolbachia strains in Anopheles and potential implications for disease control. |
Molecular Confirmation of Anopheles melas (Diptera: Culicidae) in Democratic Republic of Congo
Moyo M , Lawrence GG , Bobanga T , Irish SR . Afr Entomol 2021 29 (1) 298-300 Anopheles melas Theobald had been reported from coastal areas of the Democratic Republic of Congo (DRC), but molecular methods had never previously been used to confirm this identification. To see if An. melas was indeed present in the coastal area of DRC, Anopheles mosquitoes were collected in larval collections. Those morphologically identified as belonging to the Anopheles gambiae complex as adults were identified to species using polymerase chain reaction methods. The identity of those found to be Anopheles melas were confirmed through sequencing of the DNA. As Anopheles melas has been found to be a competent malaria vector elsewhere (Akogbeto & Romano 1999), these mosquitoes and their habitat should be considered in malaria control activities. |
Notes from the field: Identification of a Triatoma sanguisuga "kissing bug" - Delaware, 2018
Eggers P , Offutt-Powell TN , Lopez K , Montgomery SP , Lawrence GG . MMWR Morb Mortal Wkly Rep 2019 68 (15) 359 In July 2018, a family from Kent County, Delaware contacted the Delaware Division of Public Health (DPH) and the Delaware Department of Agriculture (DDA) to request assistance identifying an insect that had bitten their child’s face while she was watching television in her bedroom during the late evening hours. The parents were concerned about possible disease transmission from the insect. Upon investigation, DPH learned that the family resided in an older single-family home near a heavily wooded area. A window air conditioning unit was located in the bedroom where the bite occurred. The family reported no recent travel outside the local area. |
Novel Wolbachia strains in Anopheles malaria vectors from Sub-Saharan Africa.
Jeffries CL , Lawrence GG , Golovko G , Kristan M , Orsborne J , Spence K , Hurn E , Bandibabone J , Tantely LM , Raharimalala FN , Keita K , Camara D , Barry Y , Wat'senga F , Manzambi EZ , Afrane YA , Mohammed AR , Abeku TA , Hedge S , Khanipov K , Pimenova M , Fofanov Y , Boyer S , Irish SR , Hughes GL , Walker T . Wellcome Open Res 2018 3 113 Background: Wolbachia, a common insect endosymbiotic bacterium that can influence pathogen transmission and manipulate host reproduction, has historically been considered absent from the Anopheles (An.) genera, but has recently been found in An. gambiae s.l. populations. As there are numerous Anopheles species that have the capacity to transmit malaria, we analysed a range of species to determine Wolbachia prevalence rates, characterise novel Wolbachia strains and determine any correlation between the presence of Plasmodium, Wolbachia and the competing endosymbiotic bacterium Asaia. Methods: Anopheles adult mosquitoes were collected from five malaria-endemic countries: Guinea, Democratic Republic of the Congo (DRC), Ghana, Uganda and Madagascar, between 2013 and 2017. Molecular analysis of samples was undertaken using quantitative PCR, Sanger sequencing, Wolbachia multilocus sequence typing (MLST) and high-throughput amplicon sequencing of the bacterial 16S rRNA gene. Results: Novel Wolbachia strains were discovered in five species: An. coluzzii, An. gambiae s.s., An. arabiensis, An. moucheti and An. species 'A', increasing the number of Anopheles species known to be naturally infected. Variable prevalence rates in different locations were observed and novel strains were phylogenetically diverse, clustering with Wolbachia supergroup B strains. We also provide evidence for resident strain variants within An. species 'A'. Wolbachia is the dominant member of the microbiome in An. moucheti and An. species 'A', but present at lower densities in An. coluzzii. Interestingly, no evidence of Wolbachia/Asaia co-infections was seen and Asaia infection densities were also shown to be variable and location dependent. Conclusions: The important discovery of novel Wolbachia strains in Anopheles provides greater insight into the prevalence of resident Wolbachia strains in diverse malaria vectors. Novel Wolbachia strains (particularly high-density strains) are ideal candidate strains for transinfection to create stable infections in other Anopheles mosquito species, which could be used for population replacement or suppression control strategies. |
Identification of Anopheles species in Sud Kivu, Democratic Republic of Congo, using molecular tools.
Bandibabone J , Muhigwa JB , Agramonte NM , Zawadi B , Ombeni L , Corredor-Medina C , Lawrence GG , Chimanuka B , Irish SR . Trans R Soc Trop Med Hyg 2018 112 (8) 405-407 The mosquito fauna of the Democratic Republic of Congo remains understudied, including that of the province of Sud Kivu. To improve understanding of species presenting Sud Kivu, adult mosquitoes were collected from houses and larvae were collected from standing water at altitudes between 1627 and 1875 m above sea level. Morphological and molecular methods were used to identify the species of Anopheles collected. Six species were found, including several primary and potential secondary malaria vectors. Further work is needed to characterize mosquito populations in Sud Kivu, as well as to improve methods for identifying Anopheles in general. |
Species Identification and Resistance Status of Anopheles gambiae s.l. (Diptera: Culicidae) Mosquitoes in Guinea
Keita K , Camara D , Barry Y , Osse R , Wang L , Sylla M , Miller D , Leite L , Schopp P , Lawrence GG , Akogbeto M , Dotson EM , Guilavogui T , Keita M , Irish SR . J Med Entomol 2017 54 (3) 677-681 Insecticide resistance is one of the primary threats to the recent gains in malaria control. This is especially true in Guinea, where long-lasting insecticidal nets are currently the primary vector control intervention. To better inform the national malaria control program on the current status of insecticide resistance in Guinea, resistance bioassays were conducted, using Anopheles gambiae s.l. Giles, in three sites. Molecular analyses were also done on An. gambiae s.l. to determine the species and find whether the target-site mutations kdr and Ace1R were present. Susceptibility tests revealed resistance to DDT and pyrethroids, although mosquitoes were susceptible to deltamethrin in two of the three sites tested. Mosquitoes were susceptible to bendiocarb, except in Kissidougou, Guinea. The kdr-west mutation was widespread and the frequency was 60% or more in all sites. However, the Ace1R mutation was present in low levels. Insecticide susceptibility should continue to be monitored in Guinea to ensure insecticide-based vector control methods remain effective. |
Genome of Rhodnius prolixus, an insect vector of Chagas disease, reveals unique adaptations to hematophagy and parasite infection.
Mesquita RD , Vionette-Amaral RJ , Lowenberger C , Rivera-Pomar R , Monteiro FA , Minx P , Spieth J , Carvalho AB , Panzera F , Lawson D , Torres AQ , Ribeiro JM , Sorgine MH , Waterhouse RM , Montague MJ , Abad-Franch F , Alves-Bezerra M , Amaral LR , Araujo HM , Araujo RN , Aravind L , Atella GC , Azambuja P , Berni M , Bittencourt-Cunha PR , Braz GR , Calderon-Fernandez G , Carareto CM , Christensen MB , Costa IR , Costa SG , Dansa M , Daumas-Filho CR , De-Paula IF , Dias FA , Dimopoulos G , Emrich SJ , Esponda-Behrens N , Fampa P , Fernandez-Medina RD , da Fonseca RN , Fontenele M , Fronick C , Fulton LA , Gandara AC , Garcia ES , Genta FA , Giraldo-Calderon GI , Gomes B , Gondim KC , Granzotto A , Guarneri AA , Guigo R , Harry M , Hughes DS , Jablonka W , Jacquin-Joly E , Juarez MP , Koerich LB , Latorre-Estivalis JM , Lavore A , Lawrence GG , Lazoski C , Lazzari CR , Lopes RR , Lorenzo MG , Lugon MD , Majerowicz D , Marcet PL , Mariotti M , Masuda H , Megy K , Melo AC , Missirlis F , Mota T , Noriega FG , Nouzova M , Nunes RD , Oliveira RL , Oliveira-Silveira G , Ons S , Pagola L , Paiva-Silva GO , Pascual A , Pavan MG , Pedrini N , Peixoto AA , Pereira MH , Pike A , Polycarpo C , Prosdocimi F , Ribeiro-Rodrigues R , Robertson HM , Salerno AP , Salmon D , Santesmasses D , Schama R , Seabra-Junior ES , Silva-Cardoso L , Silva-Neto MA , Souza-Gomes M , Sterkel M , Taracena ML , Tojo M , Tu ZJ , Tubio JM , Ursic-Bedoya R , Venancio TM , Walter-Nuno AB , Wilson D , Warren WC , Wilson RK , Huebner E , Dotson EM , Oliveira PL . Proc Natl Acad Sci U S A 2015 112 (48) 14936-14941 Rhodnius prolixus not only has served as a model organism for the study of insect physiology, but also is a major vector of Chagas disease, an illness that affects approximately seven million people worldwide. We sequenced the genome of R. prolixus, generated assembled sequences covering 95% of the genome ( approximately 702 Mb), including 15,456 putative protein-coding genes, and completed comprehensive genomic analyses of this obligate blood-feeding insect. Although immune-deficiency (IMD)-mediated immune responses were observed, R. prolixus putatively lacks key components of the IMD pathway, suggesting a reorganization of the canonical immune signaling network. Although both Toll and IMD effectors controlled intestinal microbiota, neither affected Trypanosoma cruzi, the causal agent of Chagas disease, implying the existence of evasion or tolerance mechanisms. R. prolixus has experienced an extensive loss of selenoprotein genes, with its repertoire reduced to only two proteins, one of which is a selenocysteine-based glutathione peroxidase, the first found in insects. The genome contained actively transcribed, horizontally transferred genes from Wolbachia sp., which showed evidence of codon use evolution toward the insect use pattern. Comparative protein analyses revealed many lineage-specific expansions and putative gene absences in R. prolixus, including tandem expansions of genes related to chemoreception, feeding, and digestion that possibly contributed to the evolution of a blood-feeding lifestyle. The genome assembly and these associated analyses provide critical information on the physiology and evolution of this important vector species and should be instrumental for the development of innovative disease control methods. |
Phenotypic variability confirmed by nuclear ribosomal DNA suggests a possible natural hybrid zone of Triatoma brasiliensis species complex.
Costa J , Bargues MD , Neiva VL , Lawrence GG , da Rocha Gumiel MX , Oliveira G , Cabello P , Lima MM , Dotson E , Provance DW Jr , Almeida CE , Mateo L , Mas-Coma S , Dujardin JP . Infect Genet Evol 2015 37 77-87 Triatoma brasiliensis macromelasoma occurs in Pernambuco state, Brazil, which is situated between the distribution areas of Triatoma brasiliensisbrasiliensis (north) and Triatoma juazeirensis (south). T. b. macromelasoma displays greater variations in its chromatic phenotype than either T. b. brasiliensis or T. juazeirensis, and patterns reminiscent of one or the other. Experimental crosses from each of these members of the T. brasiliensis species complex generated fertile offspring suggesting that viable hybrids could be present in nature, despite their significant genetic distances. Considering the geographical position of occurrence of the T. b. macromelasoma (in Pernambuco) it was proposed to be an area capable of supporting natural hybridization between T. b. brasiliensis and T. juazeirensis. Since phenotypic variability is expected, this study investigated the existence of intermediate chromatic phenotypes for T. b. macromelasoma in various locations in areas between the T. b. brasiliensis and T. juazeirensis occurrences. Thirteen different color patterns were for the first time characterized and nine of those displayed intermediate phenotypes. Molecular analysis performed using ribosomal DNA intergenic region, grouped all within the T. brasiliensis complex. The intermediate chromatic phenotypes, molecular analysis and experimental crosses all support the distinction of a zone of hybridization that gave rise to the T. b. macromelasoma through homoploidal evolution. |
The Chagas disease domestic transmission cycle in Guatemala: parasite-vector switches and lack of mitochondrial co-diversification between Triatoma dimidiata and Trypanosoma cruzi subpopulations suggest non-vectorial parasite dispersal across the Motagua valley.
Pennington PM , Messenger LA , Reina J , Juarez JG , Lawrence GG , Dotson EM , Llewellyn MS , Cordon-Rosales C . Acta Trop 2015 151 80-7 Parasites transmitted by insects must adapt to their vectors and reservoirs. Chagas disease, an American zoonosis caused by Trypanosoma cruzi, is transmitted by several species of triatomines. In Central America, Triatoma dimidiata is a widely dispersed vector found in sylvatic and domestic habitats, with distinct populations across the endemic region of Guatemala. Our aim was to test the strength of association between vector and parasite genetic divergence in domestic environments. Microsatellite (MS) loci were used to characterize parasites isolated from T. dimidiata (n=112) collected in domestic environments. Moderate genetic differentiation was observed between parasites north and south of the Motagua Valley, an ancient biogeographic barrier (FST 0.138, p=0.009). Slightly reduced genotypic diversity and increased heterozygosity in the north (Allelic richness (Ar)=1.00-6.05, FIS -0.03) compared to the south (Ar=1.47-6.30, FIS 0.022) suggest either a selective or demographic process during parasite dispersal. Based on parasite genotypes and geographic distribution, 15 vector specimens and their parasite isolates were selected for mitochondrial co-diversification analysis. Genetic variability and phylogenetic congruence were determined with mitochondrial DNA sequences (10 parasite maxicircle gene fragments and triatomine ND4+CYT b). A Mantel test as well as phylogenetic, network and principal coordinates analyses supported at least three T. dimidiata haplogroups separated by geographic distance across the Motagua Valley. Maxicircle sequences showed low T. cruzi genetic variability (pi nucleotide diversity 0.00098) with no evidence of co-diversification with the vector, having multiple host switches across the valley. Sylvatic Didelphis marsupialis captured across the Motagua Valley were found to be infected with T. cruzi strains sharing MS genotypes with parasites isolated from domiciliated triatomines. The current parasite distribution in domestic environments can be explained by multiple parasite-host switches between vector populations and selection or bottleneck processes across the Motagua Valley, with a possible role for didelphids in domestic transmission. |
Dihydropteroate synthase mutations in Pneumocystis pneumonia: impact of applying different definitions of prophylaxis, mortality endpoints and mutant in a single cohort
Yoon C , Subramanian A , Chi A , Crothers K , Meshnick SR , Taylor SM , Beard CB , Jarlsberg LG , Lawrence GG , Avery M , Swartzman A , Fong S , Roth B , Huang L . Med Mycol 2013 51 (6) 568-75 Pneumocystis jirovecii dihydropteroate synthase (DHPS) gene mutations are well-reported. Although sulfa prophylaxis generally is associated with DHPS mutant infection, whether mutant infection is associated with poorer clinical outcomes is less clear. The differing definitions of sulfa prophylaxis and the different mortality endpoints used in these studies may be one explanation for the conflicting study results. Applying different definitions of prophylaxis, mortality endpoints and DHPS mutant to 301 HIV-infected patients with Pneumocystis pneumonia, we demonstrate that prophylaxis, irrespective of definition, increased the risk of infection with pure mutant (any prophylaxis: AOR 4.00, 95% CI: 1.83-8.76, P < 0.001) but not mixed genotypes (any prophylaxis: AOR 0.78, 95% CI: 0.26-2.36, P = 0.65). However, infection with mutant DHPS, irrespective of definition, was not associated with increased mortality (all-cause or PCP death) at the three time-intervals examined (all P > 0.05). Future studies should standardize key variables associated with DHPS mutant infection as well as examine DHPS mutant subtypes (pure mutant vs. mixed infections) - perhaps even individual DHPS mutant genotypes - so that data can be pooled to better address this issue. |
A nuclear single-nucleotide polymorphism (SNP) potentially useful for the separation of Rhodnius prolixus from members of the Rhodnius robustus cryptic species complex (Hemiptera: Reduviidae).
Pavan MG , Mesquita RD , Lawrence GG , Lazoski C , Dotson EM , Abubucker S , Mitreva M , Randall-Maher J , Monteiro FA . Infect Genet Evol 2013 14 (1) 426-433 The design and application of rational strategies that rely on accurate species identification are pivotal for effective vector control. When morphological identification of the target vector species is impractical, the use of molecular markers is required. Here we describe a non-coding, single-copy nuclear DNA fragment that contains a single-nucleotide polymorphism (SNP) with the potential to distinguish the important domestic Chagas disease vector, Rhodnius prolixus, from members of the four sylvatic Rhodnius robustus cryptic species complex. A total of 96 primer pairs obtained from whole genome shotgun sequencing of the R. prolixus genome (12,626 random reads) were tested on 43 R. prolixus and R. robustus s.l. samples. One of the seven amplicons selected (AmpG) presented a SNP, potentially diagnostic for R. prolixus, on the 280th site. The diagnostic nature of this SNP was then confirmed based on the analysis of 154 R. prolixus and R. robustus s.l. samples representing the widest possible geographic coverage. The results of a 60% majority-rule Bayesian consensus tree and a median-joining network constructed based on the genetic variability observed reveal the paraphyletic nature of the R. robustus species complex, with respect to R. prolixus. The AmpG region is located in the fourth intron of the Transmembrane protein 165 gene, which seems to be in the R. prolixus X chromosome. Other possible chromosomal locations of the AmpG region in the R. prolixus genome are also presented and discussed. (2013 Elsevier B.V.) |
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