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1.
Ricardo E. Gürtler María C. Cecere María del Pilar Fernández Gonzalo M. Vazquez-Prokopec Leonardo A. Ceballos Juan M. Gurevitz Uriel Kitron Joel E. Cohen 《PLoS neglected tropical diseases》2014,8(10)
Background
Triatoma infestans —the principal vector of the infection that causes Chagas disease— defies elimination efforts in the Gran Chaco region. This study identifies the types of human-made or -used structures that are key sources of these bugs in the initial stages of house reinfestation after an insecticide spraying campaign.Methodology and Principal Findings
We measured demographic and blood-feeding parameters at two geographic scales in 11 rural communities in Figueroa, northwest Argentina. Of 1,297 sites searched in spring, 279 (21.5%) were infested. Bug abundance per site and female fecundity differed significantly among habitat types (ecotopes) and were highly aggregated. Domiciles (human sleeping quarters) had maximum infestation prevalence (38.7%), human-feeding bugs and total egg production, with submaximal values for other demographic and blood-feeding attributes. Taken collectively peridomestic sites were three times more often infested than domiciles. Chicken coops had greater bug abundance, blood-feeding rates, engorgement status, and female fecundity than pig and goat corrals. The host-feeding patterns were spatially structured yet there was strong evidence of active dispersal of late-stage bugs between ecotopes. Two flight indices predicted that female fliers were more likely to originate from kitchens and domiciles, rejecting our initial hypothesis that goat and pig corrals would dominate.Conclusions and Significance
Chicken coops and domiciles were key source habitats fueling rapid house reinfestation. Focusing control efforts on ecotopes with human-fed bugs (domiciles, storerooms, goat corrals) would neither eliminate the substantial contributions to bug population growth from kitchens, chicken coops, and pig corrals nor stop dispersal of adult female bugs from kitchens. Rather, comprehensive control of the linked network of ecotopes is required to prevent feeding on humans, bug population growth, and bug dispersal simultaneously. Our study illustrates a demographic approach that may be applied to other regions and triatomine species for the design of innovative, improved vector control strategies. 相似文献2.
3.
Spatial and temporal dispersion of immature Ixodes dammini on Peromyscus leucopus in northwestern Illinois. 总被引:2,自引:0,他引:2
Infestation by immature Ixodes dammini and infection by Borrelia burgdorferi of the white-footed mouse Peromyscus leucopus were studied in Castle Rock State Park in northwestern Illinois during June-October 1990. Prevalence and intensity of infestation of larvae on mice were highest in August with a smaller peak in early June. The distribution of larvae on mice was highly aggregated during each of the sampling periods. Aggregation appears to be the result of a series of nonrandom successful attachments by single larvae, rather than of simultaneous attachment by clumps of larvae. Infection rate of mice by B. burgdorferi averaged 21.4% with a peak of 28.6% in August. A comparison of the numbers of attached immature ticks collected from mice and of questing ticks collected through dragging indicated that the larvae-to-nymph ratio was higher on mice than on drags. Given the low total numbers of nymphs collected from mice, this suggests a potential role for other hosts of I. dammini nymphs in northwestern Illinois. 相似文献
4.
Oviposition is a major event in the life history of mosquitoes, shaping both individual fitness and vectorial capacity. Several exogenous factors have been shown as important for the dynamic forcing of oviposition at finely (hourly) and coarsely (monthly or season to season) grained temporal scales. However, field studies addressing the interplay of weather factors on oviposition dynamics at the intermediate (days to weeks) time scale are missing. Here, we present the results from a field study that showed the oviposition dynamics of the southern house mosquito, Culex quinquefasciatus Say (Diptera: Culicidae), to be: (i) primarily dictated by relative humidity; and (ii) disrupted by rainfall events that resulted in a modified sensitivity to relative humidity. Rainfall changed the concentration of ammonia, a major limiting resource of microbes used as food by mosquito larvae. Following major rainfall events, the importance of relative humidity in forcing the oviposition dynamics also changed. Finally, our results indicate that qualitative changes in oviposition habitats modify the importance of weather variables as predictors of mosquito oviposition dynamics. 相似文献
5.
Giusi Amore Luigi Bertolotti Gabriel L. Hamer Uriel D. Kitron Edward D. Walker Marilyn O. Ruiz Jeffrey D. Brawn Tony L. Goldberg 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2010,365(1548):1871-1878
West Nile virus has evolved in concert with its expansion across North America, but little is known about the evolutionary dynamics of the virus on local scales. We analysed viral nucleotide sequences from mosquitoes collected in 2005, 2006, and 2007 from a known transmission ‘hot spot’ in suburban Chicago, USA. Within this approximately 11 × 14 km area, the viral envelope gene has increased approximately 0.1% yr−1 in nucleotide-level genetic diversity. In each year, viral diversity was higher in ‘residential’ sites characterized by dense housing than in more open ‘urban green space’ sites such as cemeteries and parks. Phylodynamic analyses showed an increase in incidence around 2005, consistent with a higher-than-average peak in mosquito and human infection rates that year. Analyses of times to most recent common ancestor suggest that WNV in 2005 and 2006 may have arisen predominantly from viruses present during 2004 and 2005, respectively, but that WNV in 2007 had an older common ancestor, perhaps indicating a predominantly mixed or exogenous origin. These results show that the population of WNV in suburban Chicago is an admixture of viruses that are both locally derived and introduced from elsewhere, containing evolutionary information aggregated across a breadth of spatial and temporal scales. 相似文献
6.
Kathryn L. Schaber T. Alex Perkins Alun L. Lloyd Lance A. Waller Uriel Kitron Valerie A. Paz-Soldan John P. Elder Alan L. Rothman David J. Civitello William H. Elson Amy C. Morrison Thomas W. Scott Gonzalo M. Vazquez-Prokopec 《PLoS computational biology》2021,17(1)
Heterogeneous exposure to mosquitoes determines an individual’s contribution to vector-borne pathogen transmission. Particularly for dengue virus (DENV), there is a major difficulty in quantifying human-vector contacts due to the unknown coupled effect of key heterogeneities. To test the hypothesis that the reduction of human out-of-home mobility due to dengue illness will significantly influence population-level dynamics and the structure of DENV transmission chains, we extended an existing modeling framework to include social structure, disease-driven mobility reductions, and heterogeneous transmissibility from different infectious groups. Compared to a baseline model, naïve to human pre-symptomatic infectiousness and disease-driven mobility changes, a model including both parameters predicted an increase of 37% in the probability of a DENV outbreak occurring; a model including mobility change alone predicted a 15.5% increase compared to the baseline model. At the individual level, models including mobility change led to a reduction of the importance of out-of-home onward transmission (R, the fraction of secondary cases predicted to be generated by an individual) by symptomatic individuals (up to -62%) at the expense of an increase in the relevance of their home (up to +40%). An individual’s positive contribution to R could be predicted by a GAM including a non-linear interaction between an individual’s biting suitability and the number of mosquitoes in their home (>10 mosquitoes and 0.6 individual attractiveness significantly increased R). We conclude that the complex fabric of social relationships and differential behavioral response to dengue illness cause the fraction of symptomatic DENV infections to concentrate transmission in specific locations, whereas asymptomatic carriers (including individuals in their pre-symptomatic period) move the virus throughout the landscape. Our findings point to the difficulty of focusing vector control interventions reactively on the home of symptomatic individuals, as this approach will fail to contain virus propagation by visitors to their house and asymptomatic carriers. 相似文献
7.
L. Tomassone P. Nuñez L. A. Ceballos R. E. Gürtler U. Kitron M. Farber 《Experimental & applied acarology》2010,52(1):93-100
Ixodid ticks were collected from vegetation and from humans, wild and domestic mammals in a rural area in the semi-arid Argentine
Chaco in late spring 2006 to evaluate their potential role as vectors of Spotted Fever Group (SFG) rickettsiae. A total of
233 adult ticks, identified as Amblyomma parvum, Amblyomma tigrinum and Amblyomma pseudoconcolor, was examined for Rickettsia spp. We identified an SFG rickettsia of unknown pathogenicity, “Candidatus Rickettsia sp. strain Argentina”, in A. parvum and A. pseudoconcolor by PCR assays targeting gltA, ompA, ompB and 17-kDa outer membrane antigen rickettsial genes. Rickettsia bellii was detected in a host-seeking male of A. tigrinum. Amblyomma parvum is widespread in the study area and is a potential threat to human health. 相似文献
8.
The activity of polymeric DNA polymerase isolated from the cytoplasm of baby hamster kidney cells is sensitive to inhibition by heparin, whereas that of nuclear DNA polymerase is resistant. Under conditions of partial inhibition, heparin brings about a change in both the Km and V values and a twofold decrease in the ability to utilize DNA templates. Heparin effectively blocks DNA synthesis irrespective of the time of addition or conditions of preincubation with the reaction components. Upon interaction with heparin, polymeric DNA polymerase undergoes dissociation accompanied by the formation of a new species of active enzyme sedimenting at 5.3S which is partially resistant to inhibition by excess heparin. High ionic strength (0.45 m) dissociates the polymeric enzyme into active dimers and monomers irrespective of the presence of heparin. The differential susceptibility of polymeric DNA polymerase into monomeric enzyme, which resembles nuclear DNA polymerase, probably reflects a conformational change during dissociation. 相似文献
9.
Rabinovich JE Kitron UD Obed Y Yoshioka M Gottdenker N Chaves LF 《Memórias do Instituto Oswaldo Cruz》2011,106(4):479-494
Host use by vectors is important in understanding the transmission of zoonotic diseases, which can affect humans, wildlife and domestic animals. Here, a synthesis of host exploitation patterns by kissing-bugs, vectors of Chagas disease, is presented. For this synthesis, an extensive literature review restricted to feeding sources analysed by precipitin tests was conducted. Modern tools from community ecology and multivariate statistics were used to determine patterns of segregation in host use. Rather than innate preferences for host species, host use by kissing-bugs is influenced by the habitats they colonise. One of the major limitations of studies on kissing-bug foraging has been the exclusive focus on the dominant vector species. We propose that expanding foraging studies to consider the community of vectors will substantially increase the understanding of Chagas disease transmission ecology. Our results indicate that host accessibility is a major factor that shapes the blood-foraging patterns of kissing-bugs. Therefore, from an applied perspective, measures that are directed at disrupting the contact between humans and kissing-bugs, such as housing improvement, are among the most desirable strategies for Chagas disease control. 相似文献
10.
Gurevitz JM Ceballos LA Gaspe MS Alvarado-Otegui JA Enríquez GF Kitron U Gürtler RE 《PLoS neglected tropical diseases》2011,5(10):e1349