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After more than a half century without recognized local dengue outbreaks in the continental United States, there were recent outbreaks of autochthonous dengue in the southern parts of Texas (2004–2005) and Florida (2009–2011). This dengue reemergence has provoked interest in the extent of the future threat posed by the yellow fever mosquito, Aedes (Stegomyia) aegypti (L.), the primary vector of dengue and yellow fever viruses in urban settings, to human health in the continental United States. Ae. aegypti is an intriguing example of a vector species that not only occurs in the southernmost portions of the eastern United States today but also is incriminated as the likely primary vector in historical outbreaks of yellow fever as far north as New York, Philadelphia, and Boston, from the 1690s to the 1820s. For vector species with geographic ranges limited, in part, by low temperature and cool range margins occurring in the southern part of the continental United States, as is currently the case for Ae. aegypti, it is tempting to speculate that climate warming may result in a northward range expansion (similar to that seen for Ixodes tick vectors of Lyme borreliosis spirochetes in Scandinavia and southern Canada in recent decades). Although there is no doubt that climate conditions directly impact many aspects of the life history of Ae. aegypti, this mosquito also is closely linked to the human environment and directly influenced by the availability of water-holding containers for oviposition and larval development. Competition with other container-inhabiting mosquito species, particularly Aedes (Stegomyia) albopictus (Skuse), also may impact the presence and local abundance of Ae. aegypti. Field-based studies that focus solely on the impact of weather or climate factors on the presence and abundance of Ae. aegypti, including assessments of the potential impact of climate warming on the mosquito's future range and abundance, do not consider the potential confounding effects of socioeconomic factors or biological competitors for establishment and proliferation of Ae. aegypti. The results of such studies therefore should not be assumed to apply in areas with different socioeconomic conditions or composition of container-inhabiting mosquito species. For example, results from field-based studies at the high altitude cool margins for Ae. aegypti in Mexico's central highlands or the Andes in South America cannot be assumed to be directly applicable to geographic areas in the United States with comparable climate conditions. Unfortunately, we have a very poor understanding of how climatic drivers interact with the human landscape and biological competitors to impact establishment and proliferation of Ae. aegypti at the cool margin of its range in the continental United States. A first step toward assessing the future threat this mosquito poses to human health in the continental United States is to design and conduct studies across strategic climatic and socioeconomic gradients in the United States (including the U.S.-Mexico border area) to determine the permissiveness of the coupled natural and human environment for Ae. aegypti at the present time. This approach will require experimental studies and field surveys that focus specifically on climate conditions relevant to the continental United States. These studies also must include assessments of how the human landscape, particularly the impact of availability of larval developmental sites and the permissiveness of homes for mosquito intrusion, and the presence of other container-inhabiting mosquitoes that may compete with Ae. aegypti for larval habitat affects the ability of Ae. aegypti to establish and proliferate. Until we are armed with such knowledge, it is not possible to meaningfully assess the potential for climate warming to i
A new tick species belonging to the genus Rhipicephalus Koch, 1844 (Acari: Ixodidae), namely, Rhipicephalus congolensis n. sp., is described. Males and females of this species are similar to those of Rhipicephalus complanatus Neumann, 1911 and Rhipicephalus planus Neumann, 1907, but it can be distinguished from them by a pattern of dense medium-sized punctations on the conscutum and scutum. Males of R. congolensis may be distinguished by the following characters: posterior half of the marginal groove deep with a sharp outer edge; anterior portion of the groove shallow with rounded edges; posteromedian groove distinct, long, and deep; adanal plates broadly sickle-shaped; bluntly pointed posteromedian spur on coxa I; and posterolateral spur on coxa I slightly longer or subequal to posteromedian spur. Females of R. congolensis may be distinguished by the following characters: outer edge of cervical grooves smooth and not clearly defined either by slope or punctations; genital aperture broad, bowl-shaped, and tripartite in appearance, with central flap flanked on either side by an oval depression; and posteromedian spur on coxa I tapering to its apex. R. congolensis is known only from the Democratic Republic of Congo, where the adults were collected from red river hogs, Potamochoerus porcus (L.), and domestic pigs, Sus scrofa (L.), within the dense equatorial forest in the districts of Équateur and Tshuapa, in the province of Équateur.
Culicoides biting midges (Diptera: Ceratopogonidae) are vectors of disease, including bluetongue and African horse sickness. Host preference of these insects is primarily regulated by olfactory cues, detected by olfactory sensilla on the antennae and maxillary palps. In this study, we analyzed the sensillum repertoire of biting midge species with known host preferences. Five different morphological sensillum types, sensilla trichodea, s. chaetica, s. ampullacea, s. coeloconica, and grooved peg sensilla, were present on the antennae of all species. In addition sensilla basiconica were present on the maxillary palps. We found that the numbers of short blunt-tipped s. trichodea, s. coeloconica, and s. basiconica are significantly higher in the ornithophilic Culicoides festivipennis (Kieffer) compared with the mammalophilic Culicoides obsoletus (Meigen) and Culicoides chiopterus (Meigen). In contrast, we found that the mammalophilic Culicoides pulicaris (L.) and the opportunistic Culicoides punctatus (Meigen) have intermediate numbers of these sensillum types. Comparison with available data from other species strongly suggests that these differences in the number of specific sensillum types, in general, are a reflection of host preference and not of phylogeny. We discuss the putative function of the individual sensillum types in relation to host volatile detection.
Simulium (Asiosimulium) furvum sp. nov. (Diptera: Simuliidae) is described from female, male, pupal, and larval specimens collected from Maewa National Park, Lampang Province, Thailand. This new species represents the fourth member of the subgenus Asiosimulium Takaoka & Chochoote, one of two small black fly subgenera endemic in the Oriental Region. It is characterized by a pear-shaped spermatheca in the female; a ventral plate in the male with a laterally compressed median keel directed ventrally and with a deep notch posteromedially, and aedeagal membrane with stout spines; and by 22 gill filaments in the pupa. Taxonomic notes are provided to separate this new species from three known species, Simulium (Asiosimulium) oblongum Takaoka & Choochote and Simulium (Asiosimulium) wanchaii Takaoka & Choochote, both from Thailand, and Simulium (Asiosimulium) suchitrae Takaoka from Nepal.
Three new harpirhynchid species of the subfamily Harpirhynchinae (Acariformes: Harpirhynchidae) are described from North American birds: Harpyrhynchoides aegolius sp. n. from Aegolius acadicus (Strigiformes: Strigidae), Harpyrhynchoides accipiter sp. n. from Accipiter striatus (Accipitriformes: Accipitridae), and Neharpyrhynchus icterus sp. n. from Icterus galbula (Passeriformes: Icteridae). Three species are recorded from new hosts from North America for the first time: Harpyrhynchoides tracheatus (Fritsch, 1954) from Buteo lineatus (Accipitriformes: Accipitridae), Harpyrhynchoides pectinifer (Lawrence, 1959) from Colaptes auratus (Piciformes: Picidae), and Harpyrhynchoides rubeculinus (Černý & Sixl, 1971) from Catharus ustulatus (Passeriformes: Turdidae). Neharpyrhynchoides novoplumaris (Moss et al., 1968) previously recorded from Cardinalis cardinalis (Passeriformes: Cardinalidae) from the United States is recollected from this host.
Distributional ranges of the ticks Dermacentor andersoni Stiles and Dermacentor variabilis (Say) in the Canadian Prairies were determined by passive surveillance and active collection. These findings were compared with historical records of both species, particularly in the province of Saskatchewan, where the northern distributional limits of both tick species occur. Before the 1960s, D.variabilis and D.andersoni were allopatric in Saskatchewan; however, since then, the distribution of D. variabilis has expanded westward and northward. Although the range of D.andersoni has remained relatively stable, range expansion of D.variabilis has resulted in a zone of sympatry at least 200 km wide. Twenty-nine species of mammals and three species of birds were identified as hosts for different life stages of these ticks.
Elevated atmospheric CO2 can alter aquatic communities via changes in allochthonous litter inputs. We tested effects of atmospheric CO2 on the invasive Aedes albopictus (Skuse) and native Aedes triseriatus (Say) (Diptera: Culicidae) via changes in competition for microbial food or resource inhibition/toxicity. Quercus alba L. litter was produced under elevated (879 ppm) and ambient (388 ppm) atmospheric CO2. Saplings grown at elevated CO2 produced greater litter biomass, which decayed faster and leached more tannins than saplings at ambient CO2. Competition was tested by raising larvae in different species and density combinations provisioned with elevated- or ambient-CO2 litter. Species-specific performance to water conditions was tested by providing single-species larval cohorts with increasing amounts of elevated- or ambient-CO2 litter, or increasing concentrations of tannic acid. Larval densities affected some fitness parameters of Ae. albopictus and Ae. triseriatus, but elevated-CO2 litter did not modify the effects of competition on population growth rates or any fitness parameters. Population growth rates and survival of each species generally were affected negatively by increasing amounts of both elevated- and ambient-CO2 litter from 0.252 to 2.016 g/liter, and tannic acid concentrations above 100 mg/liter were entirely lethal to both species. Aedes albopictus had consistently higher population growth rates than Ae. triseriatus. These results suggest that changes to litter production and chemistry from elevated CO2 are unlikely to affect the competitive outcome between Ae. albopictus and Ae. triseriatus, but that moderate increases in litter production increase population growth rates of both species until a threshold is exceeded that results in resource inhibition and toxicity.
Accurate estimation of population size is key to understanding the ecology of disease vectors, as well as the epidemiology of the pathogens they carry and to plan effective control activities. Population size can be estimated through mark—release—recapture (MRR) experiments that are based on the assumption that the ratio of recaptured individuals to the total captures approximates the ratio of marked individuals released to the total population. However, methods to obtain population size estimates usually consider pooled data and are often based on the total number of marked and unmarked captures. We here present a logistic regression model, based on the principle of the well-known Fisher—Ford method, specific for MRR experiments where the information available is the number of marked mosquitoes released, the number of marked and unmarked mosquitoes caught in each trap and on each day, and the geographic coordinates of the traps. The model estimates population size, taking into consideration the distance between release points and traps, the time between release and recapture, and the loss of marked mosquitoes to death or dispersal. The performance and accuracy of the logistic regression model has been assessed using simulated data from known population sizes. We then applied the model to data from MRR experiments with Aedes albopictus Skuse performed on the campus of “Sapienza” University in Rome (Italy).
In temperate regions, the seasonal dynamics of Aedes aegypti (L.) (Diptera: Culicidae) is mainly influenced by temperature, whereas the probability of local extinction depends on the egg mortality during the cold season. The aim of the current study was to assess the importance of temperature and egg mortality in determining the differences in the oviposition dynamics of Ae. aegypti between favorable and less favorable areas in Buenos Aires City (Argentina). Year-round temperature dynamics were monitored, and oviposition dynamics were experimentally studied with ovitraps at two sites. Daily egg mortality values were calculated from a previous study performed at the same sites. The relative contribution of the differences in temperature and egg mortality between sites to the oviposition dynamics was assessed by means of a mathematical stochastic population dynamics model for Ae. aegypti. The results showed higher temperature and lower daily egg mortality at the site where higher oviposition activity was recorded. A larger influence of temperature than of egg mortality on population abundance during most of the activity season was detected in the results of the simulations. Our results showed a temperature gradient that relates to the distance to the Río de la Plata river and contributes to explaining the spatial heterogeneity in Ae. aegypti population abundances previously reported. The hypothesis of local extinctions because of egg mortality during the winter was not supported by the present analysis. The differences between field oviposition dynamics and simulation results suggest that rainfall might also be an important variable under extremely dry conditions.
An important element of mating in the malaria vector Anopheles gambiae Giles in nature is the crepuscular mating aggregation (swarm) composed almost entirely of males, where most coupling and insemination is generally believed to occur. In this study, we mathematically characterize the oscillatory movement of male An. gambiae in terms of an established individual-based mechanistic model that parameterizes the attraction of a mosquito toward the center of the swarm using the natural frequency of oscillation and the resistance to its motion, characterized by the damping ratio. Using three-dimensional trajectory data of ten wild mosquito swarms filmed in Mali, Africa, we show two new results for low and moderate wind conditions, and indicate how these results may vary in high wind. First, we show that in low and moderate wind the vertical component of the mosquito motion has a lower frequency of oscillation and higher damping ratio than horizontal motion. In high wind, the vertical and horizontal motions are similar to one another and the natural frequencies are higher than in low and moderate wind. Second, we show that the predicted average disagreement in the direction of motion of swarming mosquitoes moving randomly is greater than the average disagreement we observed between each mosquito and its three closest neighbors, with the smallest level of disagreement occurring for the nearest neighbor in seven out of 10 swarms. The alignment of the direction of motion between nearest neighbors is the highest in high wind. This result provides evidence for flight-path coordination between swarming male mosquitoes.
Genotyping of Ixodes scapularis Say (Acari: Ixodidae) ticks could enhance understanding of the occurrence and genotypes of I. scapularis-borne pathogens. We investigated the utility of mitochondrial (mt) Cytochrome C Oxidase subunit I gene (cox1) sequences as a tool for understanding the population structure of I. scapularis collected in Canada, where we also investigated the geographic occurrence of different cox1 haplotypes. Sequences obtained from 414 ticks were one of 55 unique haplotypes, most of which grouped into one of six clades. Demographic analysis suggested that cox1 sequences have haplotype and nucleotide diversity comparable to other mt genes. All haplotypes were connected in a single minimum spanning network tree. Despite low fixation index values there were significant differences in the frequency of occurrence of haplotypes of different clades among four geographic regions: 1) Alberta to western Ontario, 2) eastern Ontario, 3) Quebec, and 4) Atlantic Provinces; suggesting that cox1 sequences could reveal population structure differences between I. scapularis in geographically separated populations of northeastern and midwestern North America. Spatial clusters of ticks of the same haplotype identified in regions of southern Quebec and southern Ontario where I. scapularis is invading were consistent with population bottlenecks associated with founder events. These findings suggest that cox1 sequences are useful for the study of I. scapularis population structure, are of sufficient diversity that spatial analyses of haplotypes can be used to identify where I. scapularis is emerging in southern Canada, and may be useful for exploring differences between northeastern and midwestern populations of I. scapularis.
A novel homolog of insect defensin, designated lucifensin II (Lucilia cuprina Wiedemann [Diptera: Calliphoridae] defensin), was purified from hemolymph extract from larvae of the blowfly L. cuprina. The full-length primary sequence of this peptide of 40 amino acid residues and three intramolecular disulfide bridges was determined by electrospray ionization-orbitrap mass spectrometry and Edman degradation and is almost identical to the previously identified sequence of lucifensin (Lucilia sericata Meigen defensin). Lucifensin II sequence differs from that of lucifensin by only one amino acid residue, that is, by isoleucine instead of valine at position 11. The presence of lucifensin II also was detected in the extracts of other larval tissues, such as gut, salivary glands, fat body, and whole body extract.
VECTOR CONTROL, PEST MANAGEMENT, RESISTANCE, REPELLENTS
Leptotrombidium pallidum (Nagoya, Miyagawa, Mitamura & Tamiya) is a primary vector of Orientia tsutsugamushi (Hyashi), the causative agent of scrub typhus. An assessment is made of the repellency to L. pallidum larvae (chiggers) of cassia bark, eucalyptus, and star anise oils and major constituents (E)-cinnamaldehyde, 1,8-cineole, and (E)-anethole of the corresponding oils. Results were compared with those of conventional repellents DEET (N,N-diethyl-3-methylbenzamide), IR3535 [(ethyl 3-[acetyl(butyl)amino]propanoate)], and permethrin. Based on the median repellent concentration (RC50) values, (E)-cinnamaldehyde, (E)-anethole, cassia bark oil, and star anise oil (RC50, 0.95–1.52 mg/cm2) exhibited significantly more potent repellency than DEET (3.85 mg/cm2). (E)-cinnamaldehyde, (E)-anethole, cassia bark oil, 1,8-cineole, and star anise oil were ≈43, 16, 11, 8, and 4 times more effective than IR3535 (CC50, 6.51%) as judged by the median climbing distance-disturbing concentration (CC50) values. The median residual duration time of repellency (RT50) was significantly more pronounced in DEET (RT50, 323 min) than in all essential oils and constituents (108–167 min). In the light of global efforts to reduce the level of highly toxic synthetic repellents, the three essential oils and their major constituents described merit further study as potential biorepellents for the control of L. pallidum populations.
Insecticides, especially pyrethroids, are important components in the vector-control effort. To better understand the development of resistance, the current study characterized resistance profiles in individual single-egg-raft colonies of a field population of Culex quinquefasciatus Say, HAmCqG0. Our study, with 104 colonies derived from each of the single-egg-rafts of HAmCqG0, indicated that the levels of resistance to permethrin in fourth instar larvae ranged from 0.4- to 280-fold compared with laboratory susceptible S-Lab larvae. We characterized the distribution of single-eggraft colonies with different levels of resistance in the HAmCqG0 population and found that 65% individual colonies had <10-fold levels of resistance to permethrin, 16% from 10- to 20- fold, 7% from 20- to 30-fold, and 12% ≥ 30-fold. We further characterized the frequency of the L-to-F kdr allelic expression of sodium channels in the single-egg-raft colonies with different levels of resistance to determine its possible role in resistance. The correlation between allelic expression and levels of resistance clearly showed the importance of L-to-F kdr mutation mediated sodium channel insensitivity in resistance development. However, our results also suggested that the sodium channel insensitivity is unlikely to be the sole mechanism and multiple mechanisms may present among the single colonies in response to insecticide resistance.
Anopheles fluviatilis James is an important malaria vector in Indian subcontinent. An. fluviatilis exists as a complex of three sibling species, of which two species, T and U, have been colonized so far. Attempts were made to study the comparative susceptibility of species T and U of the An. fluviatilis complex to rodent malaria parasite Plasmodium vinckei petteri by using Anopheles stephensi Liston as calibrator for variable infectivity in different isolates. An. stephensi, which was used as control, became readily infected, with 60–65% mosquitoes carrying developing oocysts, whereas in species T and species U, ≈50 and 63%, respectively, of mosquitoes carried oocyts. An. fluviatilis species T was found comparatively less susceptible to P. v. petteri sporogonic development compared with species U. Moreover, significantly lesser sporozoites rate (11%) was observed in species T compared with 31% in species U. Species T and species U are not considered as malaria vectors in India in the field. However, in the laboratory, both these species are able to support the malaria sporogony.
This study compares the distribution of anopheline mosquitoes in a malaria-endemic municipality (MAL) and a malaria-free municipality (FREE) in an area of the Atlantic Forest in Brazil. Simultaneous quarterly nightly captures were made in three locations in each municipality. One Shannon light trap (Shannon light traps were home made according to specifications published in Am. J. Trop. Med. 1939; 19: 131–140) (SLT) and five CDC light traps (a kind of automatic trap fed by batteries of 12 V and 7 amp/h, with dry ice as a source of CO2; John W. Hock Company, Gainesville, FL) (CLT) (two in the canopy and three at ground level) were operated from 6:00 p.m. to 6:00 a.m. More specimens were captured in MAL (362 in SLTs and 126 in CLTs) than in FREE (66 in SLTs and 59 in CLTs). For the SLTs, Simpson's dominance index was similar in MAL and FREE (D = 0.15 versus D = 0.203, P > 0.7), but Shannon's diversity index was higher for MAL (H = 1.969 versus H = 1.641, P < 0.01). For the CLTs, Simpson's dominance index was higher in MAL (D = 0.416 versus 0.2688, P < 0.001), and the Shannon diversity index was higher in FREE (H = 1.5222 versus H = 1.115, P < 0.01). In SLTs, Anopheles (Kerteszia) cruzii s.l. frequencies were higher in MAL (χ2= 23.39; P = 0.000001). In CLTs, An. cruzii s.l. was present in all strata in MAL but only in the canopy inside the forest in FREE (17 specimens). An. cruzii s.l. represented a higher proportion of anophelines in MAL (χ2 = 31; P < 0.000001). The factors that differed in these two areas were anopheline species density and An. cruzii s.l. abundance and distribution.
There were epidemic-epizootics of Rift Valley Fever (RVF) affecting humans and cattle in Madagascar in the district of Anjozorobe in 2008. Little is known about the role of Malagasy mosquitoes in the circulation of RVF virus. Therefore, we investigated the species diversity, dynamics and biology of potential RVF virus vectors in the rainforest, rainforest edge (village of Anorana), and savanna biotope (village of Antanifotsy) of this district between November 2008 and July 2010. We captured 56,605 adults of 35 different species. Anopheles squamosus (Theobald), Anopheles coustani (Laveran), Culex antennatus (Becker), Culex pipiens (L.), and Culex univittatus (Theobald) were the most abundant during the rainy season with Cx. pipiens the most abundant species in the rainforest (47%), and An. squamosus the most abundant species in the rainforest edge and in the savanna biotope (56%, 60%, respectively). Only Cx. univittatus was abundant in the dry season. The parous rate was > 60% throughout the rainy season for An. squamosus and it was > 50% from the middle to the end of the rainy season for Cx. pipiens . Two additional species have been found only at larval stage. Cattle were the most attractive bait for all species, followed by sheep and poultry. Human was the least attractive for all species. Most of the 163 bloodmeals tested were taken from cattle. Three were from poultry, one was from dog and one was a mixed bloodmeal taken from sheep and cattle. These results on vectorial capacity parameters may allow considering the involvement of mosquito transmission of the virus in the district of Anjozorobe during the recent epidemic-epizootic.
As part of the 65th Medical Brigade tick-borne disease surveillance program to determine the abundance, geographical and seasonal distributions, and tick-borne pathogens present in the Republic of Korea, dragging and sweeping methods were compared to determine their efficiency for collecting ticks in grass and deciduous, conifer, and mixed forest habitats at military training sites and privately owned lands in northern Gyeonggi Province near the demilitarized zone from April-October, 2004–2005. Three species of Ixodid ticks, Haemaphysalis longicornis, Haemaphysalis flava, and Ixodes nipponensis, were collected. Overall, H. longicornis adults and nymphs were most frequently collected from grass and deciduous forest habitats, accounting for 98.2 and 66.2%, respectively, of all ticks collected. H. flava adults and nymphs were most frequently collected from conifer and mixed forests, accounting for 81.6, and 77.8%, respectively, of all ticks collected. I. nipponensis adults and nymphs accounted for 9.3% of all ticks collected from mixed forests, were less commonly collected from deciduous (4.1%) and conifer (4.1%) forests, and infrequently collected from grass habitats (0.9%). Overall, there were no significant differences between dragging and sweeping methods for the three species when the areas sampled were similar (sweeping = 2 × the area over the same transect). Adults and nymphs of H. longicornis were most commonly collected from April-August, while those of H. flava and I. nipponensis were most commonly collected during April-July and again during October. Larvae of all three species were most frequently observed from July-September.
Gravid traps are useful tools for monitoring vector-borne pathogens in mosquitoes, particularly for those pathogens transmitted by Culex quinquefasciatus Say. One of the primary challenges in the use of gravid traps is the necessity of the inclusion of an oviposition attractant, usually an infusion of organic material, which changes in attractiveness over time. However, a standardized lure, using nonanal and trimethylamine (N TMA), has been developed and is commercially available. The N TMA lure was tested against grass infusion and tap water in Tanzania, where Cx. quinquefasciatus is a vector of lymphatic filariasis. Traps baited with grass infusion collected significantly more mosquitoes than N TMA-baited traps, which collected significantly more than traps baited with tap water. The advantages and disadvantages of the standardized lure are discussed.
The size of Aedes aegypti (L.) mosquito populations and adult survival rates have proven difficult to estimate because of a lack of consistent quantitative measures to equate sampling methods, such as adult trapping, to actual population size. However, such estimates are critical for devising control methods and for modeling the transmission of dengue and other infectious agents carried by this species. Here we take advantage of recent releases of Wolbachia-infected Ae. aegypti coupled with the results of ongoing monitoring to estimate the size of adult Ae. aegypti populations around Cairns in far north Queensland, Australia. Based on the association between released adults infected with Wolbachia and data from Biogenis Sentinel traps, we show that data from two locations are consistent with population estimates of ≈5–10 females per house and daily survival rates of 0.7–0.9 for the released Wolbachia-infected females. Moreover, we estimate that networks of Biogents Sentinel traps at a density of one per 15 houses capture around 5–10% of the adult population per week, and provide a rapid estimate of the absolute population size of Ae. aegypti. These data are discussed with respect to release rates and monitoring in future Wolbachia releases and also the levels of suppression required to reduce dengue transmission.
As a result of the increasing incidence of Lyme disease and other tick-borne pathogens in Wisconsin, we assessed the distribution of adult blacklegged ticks through collections from hunter-killed deer in 2008 and 2009 and compared results with prior surveys beginning in 1981. Volunteers staffed 21 Wisconsin Department of Natural Resources registration stations in 21 counties in the eastern half of Wisconsin in 2008 and 10 stations in seven counties in northwestern Wisconsin in 2009. In total, 786 and 300 white-tailed deer (Odocoileus virginianus) were examined in 2008 and 2009, respectively. All but three stations in 2008 were positive for ticks and all stations in 2009 were positive for ticks. The three sites negative for ticks occurred within the eastern half of Wisconsin. The results indicate that range expansion of Ixodes scapularis (Say) is continuing and the risk of tick exposure is increasing, especially in the eastern one-third of the state.
This study evaluated infection by vector-borne agents in 58 crab-eating fox (Cerdocyon thous L.) that were road-killed in an Atlantic rainforest reserve in the state of Espírito Santo, southeastern Brazil. Spleen, lung, or blood samples collected from the foxes were tested in the laboratory by a battery of polymerase chain reaction (PCR) assays targeting bacteria of the genera Rickettsia, Borrelia, Coxiella, Anaplasma, and Ehrlichia; and protozoa of the genera Babesia, Hepatozoon, and Leishmania. Of the targeted organisms, evidence of infection in the foxes was detected for Ehrlichia and Hepatozoon organisms only. Overall, six (10.3%) foxes were infected by an ehrlichial agent closely related to an ehrlichial agent recently detected in free-ranging Jaguars [(Panthera onca (L.)] in central-western Brazil, and to Ehrlichia ruminantium. For Hepatozoon, 28 (48.3%) foxes were infected by an agent closely related to Hepatozoon sp. Curupira 2 and H. americanum; and one (1.7%) fox was infected by an organism closely related to reptile-associated Hepatozoon agents. Finally, 11 (19.0%) foxes were found infested by Amblyomma cajennense (F.) nymphs, which were all PCR negative for the range of vector-borne agents cited above. Because the haplotypes found in free-ranging foxes are genetically closely related to pathogens of great veterinary importance, namely E. ruminantium and H. americanum, it is highly desirable to know if these novel organisms have any important role as agents of diseases in domestic animals and wildlife in Brazil.
Sustainable methods for managing waste associated with people and animals have been proposed in the past. Black soldier fly, Hermetia illucens (L.), larvae represent one of the more promising methods. Larvae reduce dry matter, bacteria, offensive odor, and house fly populations. Prepupae can be used as feedstuff for livestock. However, it is not known if such a method results in the proliferation of potential pathogens. Although some bacterial species have been cultured and identified from black soldier fly, a true appreciation of fly associated bacterial diversity is not known. Such information is needed to understand pathogen colonization on decomposing animal and plant waste in the presence of black soldier fly larvae as well as develop research strategies for maximizing the use of this fly to reduce waste without risking environmental harm. Using 454 sequencing, we surveyed bacterial diversity associated with successive life stages of the black soldier fly reared on plant material. Bacteria diversity classified (99.8%) across all life stages spanned six bacterial phyla with >80% bootstrap support. Bacteroidetes and Proteobacteria were the most dominant phyla associated with the black soldier fly accounting for two-thirds of the fauna identified. Many of these bacteria would go undetected because of their inability to be cultured.
Male Phlebotomus (Synphlebotomus) vansomerenae, specimens were collected together with two other members of the same subgenus between August 2010 and December 2011 in Melka Guba village near Dawa River in Liben district, southeastern Ethiopia. This is the first record of the species in Ethiopia and the first time it has been found outside of Kenya where it was originally described, extending the known distribution of this species in East Africa.
The kissing bug, Triatoma rubida (Uhler) is a common hematophagous bug in Tucson, AZ, and is responsible for causing severe allergic reactions in some bitten individuals. DEET, picaridin, tea tree oil, peppermint oil, and citronella oil were tested for repellency to T. rubida and its ability to probe and feed on a small restrained rat. No long range repellency was observed with any of the test materials. The lowest repellent concentrations observed were: 10% DEET, 7% picaridin; 30% tea tree oil, 3.3% peppermint oil, and 0.165% citronella oil. Only citronella oil was able to stop all probing and feeding by T. rubida. Citronella oil appears to be a promising potential repellent to prevent sleeping people from being bitten by kissing bugs.
The Asian tiger mosquito Aedes albopictus (Skuse,1894) is a globally invasive prominent vector of viral and parasitic pathogens. To soundly guide insecticide use in control programs it is crucial to use standardized test systems under rigorously controlled environmental conditions that allow for comparisons across laboratories. An acute standard test procedure (24 h) for insecticide resistance monitoring of mosquitoes has been published by the World Health Organization in 1998, but a standardized chronic test to monitor sublethal insecticide effects on the life cycle of mosquitoes does not yet exist. As a first step toward a standardized chronic bioassay (half-life-cycle-test), the exclusion of qualitative and quantitative food effects by means of standardized, optimal larval feeding would greatly facilitate inter-laboratory comparisons. Against this background we evaluated food qualities and quantities for the aquatic part of the A. albopictus life cycle under different thermal conditions. Five mg TetraMin (Tetra, Melle, Germany) larva-1 at 25°C rendered the lowest mortality and large pupae. Our fundamental data on A. albopictus feeding provide an opportunity to standardize experiments and thus support interlaboratory comparisons of studies on the ecotoxicology of this dangerous vector mosquito.
This study evaluated for the first time, ectoparasite infestations on dogs from urban and rural areas of the continental land of the state of Maranhâo, northeastern Brazil. In total, 622 dogs were examined for ectoparasite infestations. Overall, 392 (63.0%) were infested with ectoparasites, 154 (51.3%) of 300 urban dogs and 238 (73.9%) of 322 rural dogs. Five species of ectoparasites were found, three ticks [Rhipicephalus sanguineus (Latreille), Amblyomma ovale Koch, and Amblyommacajennense (F.) ], one flea [Ctenocephalides felis (Bouché) ], and one louse [ (Heterodoxus spininger (Enderlein) ]. The frequency of infestation by R. sanguineus tended to be higher in urban than in rural areas, whereas infestations by Amblyomma ticks and C. felis fleas tended to be higher among rural dogs. Louse (H. spininger) infestations were similarly low among all areas. Mixed infestations by at least two species of ectoparasites on the same dog were significantly more frequent on rural than on urban dogs. The most frequent mixed infestation was by R. sanguineus and C. felis, found on 11.4% of the dogs. Further studies are warranted to evaluate canine vector-borne agents in Maranhão, especially because most of the ectoparasites here reported are vectors of major vector-borne diseases, including zoonoses of continental importance.
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