Host feeding patterns of Culex mosquitoes and West Nile virus transmission, northeastern United States.To evaluate the role of Culex Culex /Cu·lex/ (ku´leks) a genus of mosquitoes found throughout the world, many species of which are vectors of disease-producing organisms. Cu·lex n. mosquitoes as enzootic en·zo·ot·ic adj. Prevalent among or restricted to animals of a specific geographic area. Used of a disease. n. An enzootic disease. enzootic peculiar to or present constantly in a location. See also endemic. and epidemic vectors for WNV WNV West Nile Virus WNV World Net Visions , we identified the source of vertebrate blood by polymerase chain reaction polymerase chain reaction (pŏl`ĭmərās') (PCR), laboratory process in which a particular DNA segment from a mixture of DNA chains is rapidly replicated, producing a large, readily analyzed sample of a piece of DNA; the process is amplification and sequencing portions of the cytochrome cytochrome (sī`təkrōm'), protein containing heme (see coenzyme) that participates in the phase of biochemical respiration called oxidative phosphorylation. b gene of mitochondrial DNA Mitochondrial DNA (mtDNA) is the DNA located in organelles called mitochondria. Most other DNA present in eukaryotic organisms is found in the cell nucleus. Nuclear and mitochondrial DNA are thought to be of separate evolutionary origin, with the mtDNA being derived from the . All Cx. restuans and 93% of Cx. pipiens acquired blood from avian hosts; Cx. salinarius fed frequently on both mammals (53%) and birds (36%). Mixed-blood meals were detected in 11% and 4% of Cx. salinarius and Cx. pipiens, respectively. American robin was the most common source of vertebrate blood for Cx. pipiens (38%) and Cx. restuans (37%). American crow represented <1% of the blood meals in Cx. pipiens and none in Cx. restuans. Human-derived blood meals were identified from 2 Cx. salinarius and 1 Cx. pipiens. Results suggest that Cx. salinarius is an important bridge vector to humans, while Cx. pipiens and Cx. restuans are more efficient enzootic vectors in the northeastern United States United States, officially United States of America, republic (2005 est. pop. 295,734,000), 3,539,227 sq mi (9,166,598 sq km), North America. The United States is the world's third largest country in population and the fourth largest country in area. . ********** West Nile virus West Nile virus, microorganism and the infection resulting from it, which typically produces no symptoms or a flulike condition. The virus is a flavivirus and is related to a number of viruses that cause encephalitis. (WNV) has become firmly established in the Western Hemisphere Western Hemisphere Part of Earth comprising North and South America and the surrounding waters. Longitudes 20° W and 160° E are often considered its boundaries. since its discovery in the New York City New York City: see New York, city. New York City City (pop., 2000: 8,008,278), southeastern New York, at the mouth of the Hudson River. The largest city in the U.S. area in 1999 (1,2). The virus has spread at an unprecedented rate throughout the continental United States United States territory, including the adjacent territorial waters, located within North America between Canada and Mexico. Also called CONUS. and to neighboring countries, where it is maintained in an enzootic cycle that involves wild birds and ornithophilic mosquitoes (3). To date, 60 mosquito species have been found to be infected with WNV in North America North America, third largest continent (1990 est. pop. 365,000,000), c.9,400,000 sq mi (24,346,000 sq km), the northern of the two continents of the Western Hemisphere. ; certain Culex spp. appear to be primary vectors, depending on region (4). In the northeastern United States, Culex pipiens, Cx. restuans, and Cx. salinarius have been implicated im·pli·cate tr.v. im·pli·cat·ed, im·pli·cat·ing, im·pli·cates 1. To involve or connect intimately or incriminatingly: evidence that implicates others in the plot. 2. as the principal vectors because they are physiologically competent (5), frequently infected with the virus in nature, and closely associated with WNV transmission foci (6). However, the precise role that each of these species plays in enzootic transmission among birds or epidemic transmission to humans is not entirely clear. Entomologic en·to·mol·o·gy n. The scientific study of insects. en  to·mo·log measures of risk may be estimated for different
mosquito species by considering their abundance, biting behavior,
prevalence of WNV infection, and vector competence. By synthesizing
these parameters, Kilpatrick et al. (7) estimated that Cx. pipiens and
Cx. restuans were responsible for up to 80% of human infections in New
York New York, state, United StatesNew York, Middle Atlantic state of the United States. It is bordered by Vermont, Massachusetts, Connecticut, and the Atlantic Ocean (E), New Jersey and Pennsylvania (S), Lakes Erie and Ontario and the Canadian province of , whereas Cx. salinarius accounted for only 4% of such infections. However, in Connecticut, the abundance of Cx. salinarius and prevalence of WNV infection in this species often approach those of Cx. pipiens (6). Observations in rural and urban sites in New York further indicate that Cx. pipiens and Cx. restuans are largely ornithophilic, whereas Cx. salinarius feeds more frequently on mammals (8), which supports the idea of a "bridge vector" role for this species. Nevertheless, collections from New Jersey indicate that mosquitoes of the Cx. pipiens complex may readily feed on mammals, including humans (9). Further blood meal analysis is required from mosquitoes collected in those habitats that support intense WNV transmission to more fully understand their respective roles as enzootic and epidemic vectors. Such information is vital to the success of any vector control Vector control is any method to limit or eradicate the vectors of vector born diseases, for which the pathogen (e.g. virusor parasite) is transmitted by a vector which can be mammals, birds or arthropods, especially insects, and more specifically mosquitoes. program. The current research initiative was undertaken to characterize the host-feeding patterns of Culex vectors and to evaluate their contribution to enzootic maintenance of WNV in wild bird populations and epidemic transmission to humans. Accordingly, blood-fed mosquitoes were collected from WNV transmission foci in Connecticut and analyzed for host source by sequencing polymerase chain reaction (PCR PCR polymerase chain reaction. PCR abbr. polymerase chain reaction Polymerase chain reaction (PCR) ) amplification products of the vertebrate cytochrome b gene. Materials and Methods Mosquito Collection Mosquitoes were collected from 31 different sites in 6 counties in Connecticut This is a List of counties in Connecticut. There are currently 8 counties in the U.S. state of Connecticut. Four of them were originally created in 1666, during the first consolidation of the colony of Connecticut from a number of smaller colonies. during a 3-year period (June through October, 2002-2004) as part of a statewide surveillance program (6) and a focused trapping effort in Fairfield County Fairfield County is the name of three counties in the United States:
Unit processes used to separate, modify, remove, and destroy objectionable, hazardous, and pathogenic substances carried by wastewater in solution or suspension in order to render the water fit and safe for intended uses. plants, dumping stations, and temporary wetlands associated with waterways. Three trap types were used: a C[O.sub.2]-baited CDC See Control Data, century date change and Back Orifice. CDC - Control Data Corporation light trap (John W. Hock hock: see wine. Co., Gainesville, FL, USA), a mosquito magnet experimental trap (American Biophysics biophysics, application of various methods and principles of physical science to the study of biological problems. In physiological biophysics physical mechanisms have been used to explain such biological processes as the transmission of nerve impulses, the muscle Corp., East Greenwich East Greenwich is the name of:
grav·id adj. Carrying eggs or developing young. gra·vid mosquito trap (11). Typically, traps were operated overnight and retrieved the following morning. Live, adult mosquitoes were transported to the laboratory, where they were promptly identified on chill tables with a stereomicroscope ster·e·o·mi·cro·scope n. A microscope equipped for stereoscopic viewing. ster e·o·mi by using descriptive keys (12). All mosquitoes with
fresh or visible blood remnants were transferred into individual 2-mL
tubes labeled according to according toprep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. species, date of collection, and locale and stored at -80[degrees]C. [FIGURE OMITTED] DNA DNA: see nucleic acid. DNA or deoxyribonucleic acid One of two types of nucleic acid (the other is RNA); a complex organic compound found in all living cells and many viruses. It is the chemical substance of genes. Isolation from Blood-fed Mosquitoes Mosquito abdomens were removed and reserved for blood-meal analysis with the aid of a dissecting dis·sect tr.v. dis·sect·ed, dis·sect·ing, dis·sects 1. To cut apart or separate (tissue), especially for anatomical study. 2. microscope. Each mosquito was dissected individually on a new microscope slide by using flame-sterilized forceps to avoid cross-contamination. DNA was isolated from the abdominal contents of blood-fed mosquitoes individually by using DNA-zol BD, (Molecular Research Center, Cincinnati, OH, USA) according to the manufacturer's recommendation. Briefly, individual mosquito abdomens were homogenized ho·mog·e·nize v. ho·mog·e·nized, ho·mog·e·niz·ing, ho·mog·e·niz·es v.tr. 1. To make homogeneous. 2. a. To reduce to particles and disperse throughout a fluid. b. with heat-sealed pipette pipette /pi·pette/ (pi-pet´) [Fr.] 1. a glass or transparent plastic tube used in measuring or transferring small quantities of liquid or gas. 2. to dispense by means of a pipette. tips in 1.5-mL tubes containing DNA-zol BD solution. The homogenates were incubated at room temperature for 5-10 min, mixed, and then centrifuged at 10,000 x g for 10 min. DNA was precipitated by adding isopropanol isopropanol, isopropyl alcohol, or 2-propanol (ī'səprō`pənōl, ī'səprō`pĭl), (CH3)2CHOH, a colorless liquid that is miscible with water. and 3-4 [micro]L Poly Acryl Carrier (Molecular Research Center). The DNA pellet was then washed twice with 75% ethanol, air-dried briefly, reconstituted in TE buffer TE buffer is a commonly used buffer solution in molecular biology, especially in procedures involving DNA or RNA. It is called "TE" buffer because it contains Tris, a common pH buffer, and EDTA, a molecule chelating cations like Mg2+. (10 mmol/L Tris-HCl, pH 8.0, 1 mmol/L EDTA EDTA: see chelating agents. ) and stored at -20[degrees]C for further analysis. Blood-meal Analysis Isolated DNA from the mosquito blood meals served as DNA templates in subsequent PCRs as previously described (8,9). PCR primers were based either on a multiple alignment of cytochrome b sequences of avian and mammalian species obtained from GenBank or previously published primer sequences cited in Table 2. All DNA templates were initially screened with avian-a and mammalian-a primer pairs, and the sequences were analyzed (Table 2). In some cases, other primer pairs (avian b, mammalian b and c) were additionally used to resolve ambiguous sequences. A Taq PCR Core Kit (Qiagen, Germantown, MD, USA) was used for all PCRs according to the manufacturer's recommendation. A 50-[micro]L reaction volume was prepared with 3 [micro]L template DNA, 4 [micro]L each primer (0.1-0.5 [micro]mol/L), 5 [micro]L 10x Qiagen PCR Buffer (containing 15 mmol/L MgC12), 1 [micro]L dNTP mix (10 mmol/L each), 0.25 [micro]L Taq DNA polymerase DNA polymerase /DNA po·lym·er·ase/ (pah-lim´er-as) any of various enzymes catalyzing the template-directed incorporation of deoxyribonucleotides into a DNA chain, particularly one using a DNA template. (1.25 U/reaction) and 32.75 [micro]L water. All PCRs were performed with the GeneAmp PCR System 9700 (Applied Biosystems Applied Biosystems, Inc. (formerly NASDAQ: ABIO) is the original name of a pioneer biotechnology company founded in 1981 in Foster City, California, among the Silicon Valley cities of the southern San Francisco Bay Area. , Foster City, CA, USA) at the ramp speed of 3[degrees]C-5[pounds sterling]C/s. PCR-amplified products were purified by using QIAquick PCR Purification Kit (Qiagen) and sequenced directly in cycle-sequencing reactions at the Keck Sequencing Facility (Yale University Yale University, at New Haven, Conn.; coeducational. Chartered as a collegiate school for men in 1701 largely as a result of the efforts of James Pierpont, it opened at Killingworth (now Clinton) in 1702, moved (1707) to Saybrook (now Old Saybrook), and in 1716 was , New Haven, CT, USA) by using the sequencer See MIDI sequencer. (music) sequencer - Any system for recording and/or playback of music via a programmable memory which stores music not as audio data, but as some representation of notes. 3730xl DNA Analyzer (Applied Biosystems). Sequences were annotated by using ChromasPro version 1.22 (Technelysium Pty Ltd PTY LTD Propriety Limited (company structure in Australia) ., Tewantin, Queensland Tewantin () is part of the Noosa district and was the original settlement of Noosa. The name Tewantin is the europeanised version of the Aboriginal name for the area, dauwadhum, meaning place of dead logs. , Australia) and identified by comparison to the GenBank DNA sequence DNA sequence Genetics The precise order of bases–A,T,G,C–in a segment of DNA, gene, chromosome, or an entire genome. See Base pair, Base sequence analysis, Chromosome, Gene, Genome. database (13). The performance of the molecular based assay was validated by isolating DNA from the blood of a number of known vertebrate species and subjecting it to PCR amplification and DNA sequencing DNA sequencing The determination of the sequence of nucleotides in a sample of DNA. . These species included American robin, American crow, black-capped chickadee chickadee (chĭk`ədē'), small North American bird of the titmouse family. The black-capped chickadee (Parus atricapillus), lively and gregarious, is a permanent resident over most of its range in the East. , blue jay, button quail button quail: see bustard quail. , common grackle common grackle n. A large grackle (Quiscalus quiscula) of eastern North America, having iridescent blackish-purple plumage and a long, wedge-shaped tail. , eastern tufted titmouse titmouse, common name for members of the Paridae, a family of passerine birds, which includes the tits, titmice, and chickadees. They are small, active birds with short, pointed bills and strong legs. , gray catbird, house sparrow house sparrow: see English sparrow. house sparrow or English sparrow One of the world's best-known and most abundant small birds (Passer domesticus, family Passeridae or Ploceidae). , mourning dove mourning dove Species (Zenaida macroura) of pigeon (family Columbidae), the common wild pigeon of North America. They have long, pointed tails, and the sides of the neck are violet and pink. Their name comes from their call's haunting, mournful tone. , northern cardinal, sharp-shinned hawk sharp-shinned hawk n. A small North American hawk (Accipiter striatus) that has short rounded wings and a long tail, and preys on other birds. , wood thrush wood thrush One of the 11 species of thrushes (in the genus Hylocichla, or Catharus) called nightingale thrushes because of their rich songs. H. mustelina is common in eastern U.S. broadleaf forests; it is 8 in. (20 cm) long and has drab, spotted plumage and a rusty-colored head. , domestic cat, domestic cow, domestic dog, horse, sheep, white-footed mouse, and white-tailed deer white-tailed deer or Virginia deer Common reddish brown deer (Odocoileus virginianus), an important game animal found alone or in small groups from southern Canada to South America. . Similar validation was also conducted with DNA isolated from blood-engorged, laboratory-reared Aedes aegypti that fed on guinea pig guinea pig (gĭn`ē), domesticated form of the cavy, Cavia porcellus, a South American rodent. It is unrelated to the pig; the name may refer to its shrill squeal. and button quail. Seasonal changes in the host feeding patterns of Cx. pipiens on selected host species were analyzed by [chi square chi square (kī), n a nonparametric statistic used with discrete data in the form of frequency count (nominal data) or percentages or proportions that can be reduced to frequencies. ] analysis for trend by using GraphPad Instat version 3.0 for Windows (GraphPad Software, San Diego San Diego (săn dēā`gō), city (1990 pop. 1,110,549), seat of San Diego co., S Calif., on San Diego Bay; inc. 1850. San Diego includes the unincorporated communities of La Jolla and Spring Valley. Coronado is across the bay. , CA, USA). Results Blood-meal sources were successfully identified by DNA sequencing from 204 of 213 Cx. pipiens, 30 of 33 Cx. restuans, and 100 of 106 Cx. salinarius. Of 204 Cx. pipiens analyzed, 190 (93.1%) contained avian blood only, 5 (2.5%) mammalian, 1 (0.5%) amphibian amphibian, in zoology amphibian, in zoology, cold-blooded vertebrate animal of the class Amphibia. There are three living orders of amphibians: the frogs and toads (order Anura, or Salientia), the salamanders and newts (order Urodela, or Caudata), and the , and 8 (3.9%) both avian and mammalian blood. Of 100 Cx. salinarius analyzed, 36 (36%) contained avian blood only, 53 (53%) mammalian, and 11 (11%) both avian and mammalian blood. All blood meals identified from Cx. restuans were avian-derived. The composition of avian-derived blood meals is shown in Table 3. We identified 27 species of birds as hosts for Cx. pipiens; the most frequently identified species were American robin (40.4% of avian and 37.7% of total), gray catbird (11.1% and 10.4%), and house sparrow (10.6% and 9.9%). Only 1 American crow-derived blood meal was identified for Cx. pipiens. Sixteen bird species were identified as hosts for Cx. restuans. American robin (36.7%) was the preferred host for Cx. restuans, as it was for Cx. pipiens, and no crow-derived blood meals were identified. We identified 13 species of birds as hosts for Cx. salinarius. The 2 most common avian species were black-capped chickadee (27.7% of avian and 11.7% of total) and American robin (25.5% and 10.8%). More crow-derived blood meals were identified (8.5% and 3.6%) in this mosquito species. A seasonal shift from American robins to other avian species was noted with Cx. pipiens (Table 4). The [chi square] test for linear trend showed that the proportion of American robin-derived blood meals decreased from June until October (p<0.0001). In June, 62.4% of all avian-derived blood meals were obtained from American robins, and this percentage declined to 26.7% in July and 38.9% in August. By September, 25.7% of the avian-derived blood meals were obtained from gray catbirds and 20.0% from mourning doves, while none was identified as being from American robins. An analysis of the mammalian blood meal sources for Cx. pipiens and Cx. salinarius is shown in Table 5. We identified 10 host species for Cx. salinarius and 7 for Cx. pipiens. White-tailed deer (Odocoileus virginianus) was the most frequently identified host for Cx. salinarius (67.2% of mammalian and 38.7% of total). Human-derived blood meals were identified from 2 Cx. salinarius and 1 Cx. pipiens. Discussion Our analysis on the blood-feeding behavior of Culex mosquitoes provides insight into their relative roles as enzootic and epidemic vectors of WNV in this region of the northeastern United States. We found that Cx. pipiens and Cx. restuans predominantly feed on avian hosts and focus their feeding activity on several key bird species that can support WNV transmission, in particular, American robins, gray catbirds, and house sparrows. By contrast, we found that Cx. salinarius feeds more opportunistically than Cx. pipiens and Cx. restuans and includes a relatively high proportion of mosquitoes with mixed blood meals from both avian and mammalian sources. This finding suggests that Cx. salinarius serves as a bridge vector by transferring WNV from viremic birds to mammalian hosts. The preponderance of WNV isolations obtained from Cx. pipiens in surveillance activities conducted over the last 6 years (6,10,14,15) clearly incriminates this species as the predominant mosquito vector in this region. However, while enzootic transmission to birds is strongly supported by a number of host-preference studies on regional populations (8,9,16-18), no consensus has been reached on the role of Cx. pipiens in epidemic transmission of WNV to humans in the northeastern United States. Apperson et al. (9) recently identified mammalian-derived blood meals in 38% of blood-fed Cx. pipiens, 10.8% of which were human-derived ([approximately equal to] 2.5% overall), collected from New Jersey. This finding led these researchers to conclude that Cx. pipiens was likely an epidemic vector in that region. This interpretation was viewed as consistent with the incidence of human cases in 3 densely populated urban areas of Connecticut in 2002, where most viral isolations (78%) were from Cx. pipiens (6). Kilpatrick et al. (7), integrating WNV testing data from New York from 2000 to 2003 with information on mosquito abundance, infection prevalence, vector competence, and biting behavior, further suggested that Cx. pipiens and Cx. restuans were responsible for up to 80% of human infections in that region. However, the validity of their conclusions was based on the identification of mammalian-derived blood in =19% of these 2 species and the assumption that humans were also included. Our analysis of blood meals from wild-caught female Cx. pipiens from established WNV foci in Connecticut is inconsistent with this supposition, as this species shows a strong tendency for avian blood and little inclination for mammalian hosts, including humans. We, therefore, conclude that while Cx. pipiens may occasionally feed on humans, it may not be the predominant vector of WNV to humans in our region of the northeastern United States. This finding is compatible with the lack of any mammalian-derived blood meals in blooded Cx. pipiens collected from suburban locales in nearby Westchester County, New York '' Westchester County is a primarily suburban county located in the U.S. state of New York with about 950,000 residents. It is part of the New York Metropolitan Area. It was named after Chester, in England, and the county seat is White Plains. (9), but contrasts sharply with a recent study conducted in Delaware, where 69% of the blood meals taken by Cx. pipiens were from large mammals (19), which suggests a difference in host preference from more southern regions of its range. Examination of the blood-fed mosquitoes in the present study showed an exclusively ornithophilic nature of Cx. restuans; all analyzed blood meals were from avian species. These findings were consistent with prior host preference studies (8,9,16,20) and strongly support the view that this predominant "early season" species is most likely involved in initiation and amplification of WNV transmission among wild birds and rarely, if ever, feeds on humans in this region. This finding differs from a recent blood-meal analysis by Gingrich and Williams (19), who found that a limited number (n = 9) of Cx. restuans from Delaware were highly mammalophilic (9:1 mammal-to-bird ratio). However, they concluded that this species was still primarily an enzootic vector since they never collected it in human landing collections. Our findings regarding the blood-feeding patterns of Cx. salinarius reinforce those of previous studies (18,20-25) and indicate that this species feeds indiscriminately on both birds and mammals, including humans. By using separate PCR primer pairs for different vertebrate classes, we find that 11% of Cx. salinarius acquired blood meals from both avian and mammalian sources, versus [approximately equal to] 4% for Cx. pipiens. We cannot say whether all or most of these double-source blood meals represent multiple feeding episodes during the same gonotrophic cycle or the detection of residual DNA from a prior egg-laying cycle. However, mixed-source blood meals have been reported for a number of Culex species by using different methods for blood-meal identification (8,16). Regardless, our findings indicate that a relatively large fraction of the Cx. salinarius population readily feeds on both birds and mammals, which is a necessary condition for epidemic transmission to humans. The opportunistic feeding pattern of Cx. salinarius, in conjunction with its physiologic competence to transmit WNV (26), high infection rates in nature (10,14,15), and seasonal distribution that overlaps with human cases (6), all indicate that this species is a bridge vector of WNV to humans in the northeastern United States. White-tailed deer were the single most important source of blood for Cx. salinarius in our study, which supports similar findings from New Jersey (9,18). The apparent affinity of Cx. salinarius for deer over other mammalian hosts is likely a function of deer's availability, as they are the most abundant large mammals in the region after humans. The role of deer in the ecology and transmission dynamics of WNV is unknown. Seroprevalence seroprevalence Immunology The proportion of a population that is seropositive–ie, has been exposed to a particular pathogen or immunogen; the seropositivity of a population is calculated as the number of individuals who produce a particular antibody divided of WNV antibodies was 0%-6% among hunter-killed deer from New Jersey in 2001 (27), which suggests infrequent exposure to WNV relative to avian hosts, but frequency of exposure is still greater than that in humans (28). Widespread abundance of deer could be zooprophylactic by diverting feeding from avian amplifying hosts to deer. This possibility merits further study. Several avian hosts are highly susceptible to WNV infection and can support viremia viremia /vi·re·mia/ (vi-re´me-ah) the presence of viruses in the blood. vi·re·mi·a n. The presence of viruses in the bloodstream. sufficient to infect culicine culicine /cu·li·cine/ (ku´li-sin) (ku´li-sin) 1. a member of the genus Culex or related genera. 2. vectors. Reservoir competence values expressed as the duration and magnitude of infectious-level viremia were evaluated for 25 bird species and shown to be highest for passerine passerine Any perching bird. All passerines belong to the largest order of birds, Passeriformes, and have feet specialized for holding onto a horizontal branch (perching). The passerine foot has three forward-directed toes and one backward-directed toe. birds, including the blue jay, common grackle, house finch, American crow, house sparrow, and American robin (29). Field data further implicate im·pli·cate tr.v. im·pli·cat·ed, im·pli·cat·ing, im·pli·cates 1. To involve or connect intimately or incriminatingly: evidence that implicates others in the plot. 2. a few species as reservoir hosts in northeastern United States on the basis of their exposure to WNV. When abundance and seroprevalence data were combined, house sparrows were estimated to be the most commonly infected bird species in New York City (30,31). These findings, combined with reservoir competence data, suggest that house sparrows are amplifying hosts in urban locales; however, other resident bird species, such as the northern cardinal, house finch, and gray catbird, were also frequently exposed to WNV (30). We show that in Connecticut, Cx. pipiens and Cx. restuans acquire blood meals predominately from American robins, implicating im·pli·cate tr.v. im·pli·cat·ed, im·pli·cat·ing, im·pli·cates 1. To involve or connect intimately or incriminatingly: evidence that implicates others in the plot. 2. this species as a reservoir host for WNV. American robins are moderately competent and develop infectious-level viremia for a duration of [approximately equal to] 3 days (29). This species is most abundant in Connecticut from early spring to midsummer (32). Therefore, they may support more early- to mid-season (June-August) amplification of the virus. Our findings of a seasonal shift in Cx. pipiens from American robins to other avian species support this hypothesis. We found that Cx. pipiens and Cx. restuans rarely fed upon American crows, despite their abundance (32) and high death rate from WNV infection throughout the region (33-35). Similar findings were reported from Cx. pipiens-complex mosquitoes collected from New York (8) and New Jersey (9). This finding suggests that American crows may also acquire WNV through other means in addition to mosquito transmission. American crows are susceptible to WNV infection by oral ingestion ingestion /in·ges·tion/ (-chun) the taking of food, drugs, etc., into the body by mouth. in·ges·tion n. 1. The act of taking food and drink into the body by the mouth. 2. of the virus in aqueous solution and by eating infected bird carcasses (29). These birds are aggressive nest raiders and, therefore, could also acquire WNV infection by eating infected nestling birds. Transmission could also occur directly from bird to bird, as has been demonstrated in laboratory settings for this and other species (29,36,37). Our findings indicate that American crows may not be the primary amplifying hosts for infecting Culex mosquitoes with WNV in this region of the northeastern United States. Alternatively, we find that other common birds, including American robins, gray catbirds, and house sparrows, may play a greater role in supporting enzootic transmission. Our PCR-based method took advantage of the conservation and diversity of mitochondrial mitochondrial pertaining to mitochondria. mitochondrial RNAs a unique set of tRNAs, mRNAs, rRNAs, transcribed from mitochondrial DNA by a mitochondrial-specific RNA polymerase, that account for about 4% of the total cell RNA that sequences in identifying the source of vertebrate blood from mosquitoes. Mitochondrial DNA is a useful marker in phylogenetic phy·lo·ge·net·ic adj. 1. Of or relating to phylogeny or phylogenetics. 2. Relating to or based on evolutionary development or history. studies and molecular systematics systematics: see classification. because of its maternal inheritance maternal inheritance Genetics An inheritance pattern displayed by mitochondrial genes that are propagated from one generation to the next through mom; the mitochondria of the zygote come almost entirely from the ovum. See Gene, Inheritance, Mitochondria, Zygote. , haploid haploid /hap·loid/ (hap´loid) 1. having half the number of chromosomes characteristically found in the somatic (diploid) cells of an organism; typical of the gametes of a species whose union restores the diploid number. nature, and rapid rate of evolution (38). The cytochrome b gene, in particular, has successfully been used to identify taxonomic groups to the subspecies subspecies, also called race, a genetically distinct geographical subunit of a species. See also classification. level and these sequences are publicly accessible from a wide array of different bird and mammal species in the GenBank database. By sequencing portions of the cytochrome b gene, we unambiguously identified the blood-meal source to the species level, which represents an improvement in sensitivity and specificity over earlier analyses. Acknowledgments We thank Louis A. Magnarelli for providing vertebrate blood samples and John Shepard, Michael Thomas, Terrill Goodman, Michael Vasil, and our mosquito/arbovirus support group for collecting and identifying mosquitoes. Funding for this research was provided by Laboratory Capacity for Infectious Disease Infectious disease A pathological condition spread among biological species. Infectious diseases, although varied in their effects, are always associated with viruses, bacteria, fungi, protozoa, multicellular parasites and aberrant proteins known as prions. Cooperative Agreement Number U50/CCU6806-01-1 from the Centers for Disease Control and Prevention Centers for Disease Control and Prevention (CDC), agency of the U.S. Public Health Service since 1973, with headquarters in Atlanta; it was established in 1946 as the Communicable Disease Center. , United States Department of Agriculture United States Department of Agriculture (USDA), n.pr established in 1862, USDA is responsible for the safety of meat, poultry, and egg products. It conducts ongoing research in areas from human nutrition to new crop technologies and also helps ensure open Specific Cooperative Agreement Number 58-6615-1-218, and Hatch Grant CONH00768. Dr Molaei is a postdoctoral scientist at the Connecticut Agricultural Experiment Station Connecticut Agricultural Experiment Station is a site significant for its ... It was declared a National Historic Landmark in 19.[1],[2] References 1. ^ National Register Information System. . His current research interests include epidemiology of WNV, in particular mosquito-host interactions and host feeding patterns of mosquito vectors. References (1.) Anderson JF, Andreadis TG, Vossbrinck CR, Tirrell S, Wakem EM, French RA, et al. Isolation of West Nile virus from mosquitoes, crows, and a Cooper's hawk in Connecticut. Science. 1999;286:2331-3. (2.) Lanciotti R, Roehrig JT, Deubel V, Smith J, Parker M, Steele K, et al. Origin of the West Nile virus responsible for an outbreak of encephalitis encephalitis (ĕnsĕf'əlī`təs), general term used to describe a diffuse inflammation of the brain and spinal cord, usually of viral origin, often transmitted by mosquitoes, in contrast to a bacterial infection of the meninges in the northeastern United States. Science. 1999;286:2333-7. (3.) Komar N. West Nile virus: epidemiology and ecology in North America. Adv Virus Res. 2003;61:185-234. (4.) Centers for Disease Control and Prevention. West Nile virus [homepage on the Internet]. 2005 Sep 14 [cited 2006 Jan 19]. Available from http://www.cdc.gov/ncidod/dvbid/westnile/mosquitoSpecies.htm (5.) Turell MJ, Dohm DJ, Sardelis MR, Oguinn ML, Andreadis TG, Blow JA. An update on the potential of North American North American named after North America. North American blastomycosis see North American blastomycosis. North American cattle tick see boophilusannulatus. mosquitoes (Diptera: Culicidae) to transmit West Nile virus. J Med Entomol. 2005;42:57-62. (6.) Andreadis TG, Anderson JF, Vossbrinck CR, Main AJ. Epidemiology of West Nile virus in Connecticut: a five-year analysis of mosquito data 1999-2003. Vector Borne Zoonotic Zoonotic A disease which can be spread from animals to humans. Mentioned in: Zoonosis Dis. 2004;4:360-78. (7.) Kilpatrick AM, Kramer LD, Campbell SR, Alleyne EO, Dobson AP, Daszak P. West Nile virus risk assessment and the bridge vector paradigm. Emerg Infect Dis. 2005; 11:425-9. (8.) Apperson CS, Harrison BA, Unnasch TR, Hassan HK, Irby WS, Savage HM, et al. Host-feeding habits of Culex and other mosquitoes (Diptera: Culicidae) in the borough of Queens in New York City, with characters and techniques for identification of Culex mosquitoes. J Med Entomol. 2002;39:777-85. (9.) Apperson CS, Hassan HK, Harrison BA, Savage HM, Aspen SE, Farajollahi A, et al. Host feeding patterns of established and potential mosquito vectors of West Nile virus in the eastern United States. Vector Borne Zoonotic Dis. 2004;4:71-82. (10.) Anderson JF, Andreadis TG, Main AJ, Kline DL. Prevalence of West Nile virus in tree canopy-inhabiting Culex pipiens and associated mosquitoes. Am J Trop Med Hyg. 2004;71:112-9. (11.) Reiter P. A portable, battery-powered trap for collecting gravid Culex mosquitoes. Mosq News. 1983;43:496-8. (12.) Darsie RJ, Ward RA. Identification and geographic distribution of mosquitoes of North America, north of Mexico. Mosq Syst. 1981;1:1-313. (13.) The National Center for Biotechnology Information The National Center for Biotechnology Information (NCBI) is part of the United States National Library of Medicine (NLM), a branch of the National Institutes of Health. The NCBI is located in Bethesda, Maryland and was founded in 1988. . GenBank. Available from http://www.nebi.nhn.nih.gov/Genbank/index.html (14.) Andreadis TG, Anderson JF, Vossbrinck CR. Mosquito surveillance for West Nile virus in Connecticut, 2000: isolation from Culex pipiens, Cx. restuans, Cx. salinarius, and Culiseta melanura. Emerg Infect Dis. 2001;7:670-4. (15.) Kulsekera VL, Kramer L, Nasci RS, Mostashari F, Cherry B, Trock SC, et al. West Nile virus infection in mosquitoes, birds, horses, and humans, Staten Island, New York, 2000. Emerg Infect Dis. 2001;7:722-5. (16.) Magnarelli LA. Host feeding patterns of Connecticut mosquitoes (Diptera: Culicidae). Am J Trop Med Hyg. 1977;26:547-52. (17.) Tempelis CH. Host-feeding patterns of mosquitoes, with a review of advances in analysis of blood meals by serology Serology The division of biological science concerned with antigen-antibody reactions in serum. It properly encompasses any of these reactions, but is often used in a limited sense to denote laboratory diagnostic tests, especially for syphilis. . J Med Entomol. 1975;11:635-53. (18.) Crans Crans is the name or part of the name of several places:
(19.) Gingrich J, Williams GM. Host-feeding patterns of suspected West Nile virus mosquito vectors in Delaware, 2001-2002. J Am Mosq Control Assoc. 2005;21:194-200. (20.) Irby WS, Apperson CS. Hosts of mosquitoes in the coastal plain of North Carolina North Carolina, state in the SE United States. It is bordered by the Atlantic Ocean (E), South Carolina and Georgia (S), Tennessee (W), and Virginia (N). Facts and Figures Area, 52,586 sq mi (136,198 sq km). Pop. . J Med Entomol. 1988;25:85-93. (21.) Edman JD. Host-feeding patterns of Florida mosquitoes. 3. Culex (Culex) and Culex (Neoeulex). J Med Entomol. 1974;11:95-104. (22.) Cupp E, Stokes GM. Identification of bloodmeals from mosquitoes collected in light traps and dog-baited traps. Mosq News. 1973;33:39-41. (23.) Murphey F, Burbutis PP, Bray DF. Bionomics bi·o·nom·ics n. (used with a sing. verb) See ecology. [From French bionomique, pertaining to ecology, from bionomie, ecology : Greek bio-, bio- of Culex salinarius Coquillett. II. Host acceptance and feeding by adult females of Cx. salinarius and other mosquito species. Mosq News. 1967;27:366-74. (24.) Edman J, Downe AER. Host-blood sources and multiple habits of mosquitoes in Kansas. Mosq News. 1964;24:154-60. (25.) Cupp E, Stokes GM. Feeding patterns of Culex salinarius Coquillett in Jefferson Parish, Louisiana Coordinates: Jefferson Parish is a parish in Louisiana that includes most of the suburban New Orleans. The seat of parish government is Gretna. According to the 2000 census, Jefferson had a population of 455,466. . Mosq News. 1976;36:332-5. (26.) Sardelis MR, Turell MJ, Dohm DJ, O'Guinn ML. Vector competence of selected North American Culex and Coquillettidia mosquitoes for West Nile virus. Emerg Infect Dis. 2001;7:1018-22. (27.) Farajollahi A, Gates R, Crans W, Komar N. Serologic se·rol·o·gy n. pl. se·rol·o·gies 1. The science that deals with the properties and reactions of serums, especially blood serum. 2. evidence of West Nile virus and St. Louis encephalitis St. Louis encephalitis see St. Louis encephalitis. virus infections in white-tailed deer (Odocoileus virginianus) from New Jersey, 2001. Vector Borne Zoonotic Dis. 2004;4:379-83. (28.) Centers for Disease Control and Prevention. Serosurveys for West Nile virus infection--New York and Connecticut counties, 2000. MMWR MMWR Morbidity & Mortality Weekly Report Epidemiology A news bulletin published by the CDC, which provides epidemiologic data–eg, statistics on the incidence of AIDS, rabies, rubella, STDs and other communicable diseases, causes of mortality–eg, Morb Mortal Wkly Rep. 2001;50:37-9. (29.) Komar N, Langevin S, Hinten S, Nemeth N, Edwards E, Hettler D, et al. Experimental infection of North American birds <onlyinclude> This list of North American birds is a comprehensive listing of all the bird species known from the North American continent north of Mexico. </onlyinclude> with the New York 1999 strain of West Nile virus. Emerg Infect Dis. 2003;9:311-22. (30.) Komar N, Burns J, Dean C, Panella NA, Dusza S, Cherry B. Serologic evidence for West Nile virus infection in birds in Staten Island, New York, after an outbreak in 2000. Vector Borne Zoonotic Dis. 2001;1:191-6. (31.) Nasci RS, Komar N, Marfin AA, Ludwig GV, Kramer LD, Daniels TJ, et al. Detection of West Nile virus-infected mosquitoes and seropositive seropositive /se·ro·pos·i·tive/ (-poz´i-tiv) showing positive results on serological examination; showing a high level of antibody. se·ro·pos·i·tive adj. juvenile birds in the vicinity of virus-positive dead birds. Am J Trop Med Hyg. 2002;67:492-6. (32.) Hanisek G. Connecticut birds by the season. The Connecticut Warbler warbler, name applied in the New World to members of the wood warbler family (Parulidae) and in the Old World to a large family (Sylviidae) of small, drab, active songsters, including the hedge sparrow, the kinglet, and the tailorbird of SE Asia, . 2005;25:1-44. (33.) Hadler J, Nelson R, McCarthy T, Andreadis T, Lis MJ, French R, et al. West Nile virus surveillance in Connecticut in 2000: an intense epizootic ep·i·zo·ot·ic adj. Affecting a large number of animals at the same time within a particular region or geographic area. Used of a disease. ep without high risk for severe human disease. Emerg Infect Dis. 2001;7:636-42. (34.) Hochachka WM, Dhondt AA, McGowan KJ, Kramer LD. Impact of West Nile virus on American crows in the northeastern United States, and its relevance to existing monitoring program. EcoHealth. 2004;1:60-8. (35.) Julian KG, Eidson M, Kipp AM, Weiss E, Petersen LR, Miller JR, et al. Early season crow mortality as a sentinel for West Nile virus disease in humans, northeastern United States. Vector Borne Zoonotic Dis. 2002;2:145-55. (36.) Komar N, Lanciotti R, Bowen R, Langevin S, Bunning M. Detection of West Nile virus in oral and cloacal cloacal emanating from or pertaining to cloaca. cloacal kiss the contact which occurs during insemination in birds when the vent of the female is everted exposing the cloacal mucosa against which the phallus of the male is pressed. swabs collected from bird carcasses. Emerg Infect Dis. 2002;8:741-2. (37.) McLean RG, Ubico SR, Docherty DE, Hansen WR, Sileo L, McNamara TS. West Nile virus transmission and ecology in birds. Ann N Y Acad Sci. 2001;951:54-7. (38.) Moore W, DeFilipps VR. Taxonomic resolution based on cytochrome b DNA. In: Mindell DP, editor. Avian molecular evolution and systematics. San Diego: Academic Press; 1997. (39.) Cicero C, Johnson NK. Higher-level phylogeny of new world vireos (aves: vireonidae) based on sequences of multiple mitochondrial DNA genes. Mol Phylogen Evol. 2001;20:27-40. (40.) Sorenson M, Ast J, Dimcheff DE, Yuri T, Mindell DP. Primers for a PCR-based approach to mitochondrial genome sequencing in birds and other vertebrates. Mol Phylogenet Evol. 1999;12:105-14. Address for correspondence: Goudarz Molaei, Connecticut Agricultural Experiment Station, 123 Huntington St, PO Box 1106, New Haven, CT 06504, USA; fax: 203-974-8502; email: Goudarz.Molaei@po.state.ct.us Goudarz Molaei, * Theodore G. Andreadis, * Philip M. Armstrong, * John F. Anderson, * and Charles R. Vossbrinck * * The Connecticut Agricultural Experiment Station, New Haven, Connecticut, USA
Table 1. No. Culex mosquitoes collected for blood-meal analysis from 6
counties in Connecticut, 2002-2004
County Human population density (per [mi.sup.2]) Culex pipiens
Fairfield 1,410 195
New Haven 1,361 17
Hartford 1,166 --
Middlesex 420 --
New London 389 1
Tolland 332 --
Total -- 213
County Cx. restuans Cx. salinarius
Fairfield 25 51
New Haven 5 51
Hartford 1 --
Middlesex -- 2
New London 1 2
Tolland 1 --
Total 33 106
Table 2. Sequences of primers, length of amplification products, and
thermal cycling conditions used in polymerase chain reactions for
blood-meal analysis
Product
Primer name Sequence (bp)
Avian a GAC TGT GAC AAA ATC CCN TTC CA (f) * 508
GGT CTT CAT CTY HGG YTT ACA AGA C (r)
Avian b CCC TCA GAA TGA TAT TTG TCC TCA (f) ([dagger]) 515
CCT CAG AAK GAT ATY TGN CCT CAK GG (r)
Mammalian a CGA AGC TTG ATA TGA AAA ACC ATC GTT G (f) 772
TGT AGT TRT CWG GGT CHC CTA (r)
Mammalian b GCG TAC GCA ATC TTA CGA TCA A (f) 195
CTG GCC TCC AAT TCA TGT GAG (r)
Mammalian c CCA TCC AAC ATC TCA GCA TGA TGA AA (f) 395
GCC CCT CAG AAT GAT ATT TGT CCT CA (r)
Cycling condition
Primer name Denaturation Annealing
Avian a 94[degrees]C (30 s) 60[degrees]C (50 s)
Avian b 95[degrees]C (1 min) 58[degrees]C (1 min)
Mammalian a 94[degrees]C (30 s) 55 [degrees]C (45 s)
Mammalian b 95[degrees]C (1 min) 54[degrees]C (1 min)
Mammalian c 95[degrees]C (1 min) 55 [degrees]C (1 min)
Cycling condition
Primer name Extension No.cycles
Avian a 72[degrees]C (40 s) 36
Avian b 72[degrees]C (1 min) 35
Mammalian a 72[degrees]C (1.5 min) 36
Mammalian b 72[degrees]C (1 min) 32
Mammalian c 72[degrees]C (1 min) 32
* Reference (39).
([dagger]) Reference (40).
Table 3. Number and percentage of avian blood meals identified from
Culex mosquitoes collected in Connecticut, 2002-2004
Culex pipiens *
% of avian % of total
Avian species No. (n = 198) (n = 212)
American robin (Turdus migratorius) 80 40.4 37.7
Gray catbird (Dumetella carolinensis) 22 11.1 10.4
House sparrow (Passer domesticus) 21 10.6 9.9
European starling (Stumus vulgaris) 14 7.1 6.6
Mourning dove (Zenaida macroura) 13 6.6 6.1
Black-capped chickadee (Poecile
atricapilla) 9 4.5 4.2
Common grackle (Quiscalus quiscula) 8 4.0 3.8
Wild turkey (Meleagris gallopavo) 6 3.0 2.8
Northern cardinal (Cardinalis
cardinalis) 4 2.0 1.9
House finch (Carpodacus mexicanus) 3 1.5 1.4
Barn swallow (Hirundo rustica) 2 1.0 0.9
American crow (Corvus brachyrhynchos) 1 0.5 0.5
Sharp-shinned hawk (Accipiter striatus) 1 0.5 0.5
Brown-headed cowbird (Molothrus ater) 1 0.5 0.5
Canada goose (Branta canadensis) 1 0.5 0.5
Wood thrush (Hylocichla mustelina) 1 0.5 0.5
Red-winged blackbird (Agelaius
phoeniceus) 1 0.5 0.5
Cedar waxwing (Bombycilla cedrorum) 1 0.5 0.5
Red-tailed hawk (Buteo jamaicensis) 1 0.5 0.5
Green heron (Butorides virescens) 1 0.5 0.5
Rock dove (Columba livia) 1 0.5 0.5
Song sparrow (Melospiza melodia) 1 0.5 0.5
Indigo bunting (Passerina cyanea) 1 0.5 0.5
House wren (Troglodytes aedon) 1 0.5 0.5
Willow flycatcher (Empidonax traillii) 1 0.5 0.5
Black-and-white warbler (Mniotilta
varia) 1 0.5 0.5
Northern waterthrush 1 0.5 0.5
(Seiurus noveboracensis)
Wood duck (Aix sponsa) -- -- --
Prairie warbler (Dendroica discolor) -- -- --
Mallard (Anas platyrhynchos) -- -- --
Northern oriole (Icterus galbula) -- -- --
Black-crowned night heron -- -- --
(Nyctiocorax nyctiocorax)
Rose-breasted grosbeak -- -- --
(Pheucticus ludovicianus)
Blue-headed vireo (Vireo solitarius) -- -- --
Cx. restuans
%
Avian species No. (n = 30)
American robin (Turdus migratorius) 11 36.7
Gray catbird (Dumetella carolinensis) 2 6.7
House sparrow (Passer domesticus) -- --
European starling (Stumus vulgaris) 1 3.3
Mourning dove (Zenaida macroura) 2 6.7
Black-capped chickadee (Poecile
atricapilla) 1 3.3
Common grackle (Quiscalus quiscula) 2 6.7
Wild turkey (Meleagris gallopavo) 1 3.3
Northern cardinal (Cardinalis
cardinalis) 2 6.7
House finch (Carpodacus mexicanus) -- --
Barn swallow (Hirundo rustica) -- --
American crow (Corvus brachyrhynchos) -- --
Sharp-shinned hawk (Accipiter striatus) 1 3.3
Brown-headed cowbird (Molothrus ater) 1 3.3
Canada goose (Branta canadensis) 1 3.3
Wood thrush (Hylocichla mustelina) 1 3.3
Red-winged blackbird (Agelaius
phoeniceus) -- --
Cedar waxwing (Bombycilla cedrorum) -- --
Red-tailed hawk (Buteo jamaicensis) -- --
Green heron (Butorides virescens) -- --
Rock dove (Columba livia) -- --
Song sparrow (Melospiza melodia) -- --
Indigo bunting (Passerina cyanea) -- --
House wren (Troglodytes aedon) -- --
Willow flycatcher (Empidonax traillii) -- --
Black-and-white warbler (Mniotilta
varia) -- --
Northern waterthrush -- --
(Seiurus noveboracensis)
Wood duck (Aix sponsa) -- --
Prairie warbler (Dendroica discolor) 1 3.3
Mallard (Anas platyrhynchos) -- --
Northern oriole (Icterus galbula) 1 3.3
Black-crowned night heron -- --
(Nyctiocorax nyctiocorax)
Rose-breasted grosbeak 1 3.3
(Pheucticus ludovicianus)
Blue-headed vireo (Vireo solitarius) 1 3.3
Cx. Salinarius ([dagger])
% of avian % of total
Avian species No. (n = 47) (n = 111)
American robin (Turdus migratorius) 12 25.5 10.8
Gray catbird (Dumetella carolinensis) -- -- --
House sparrow (Passer domesticus) 5 10.6 4.5
European starling (Stumus vulgaris) 1 2.1 0.9
Mourning dove (Zenaida macroura) 3 6.4 2.7
Black-capped chickadee (Poecile
atricapilla) 13 27.7 11.7
Common grackle (Quiscalus quiscula) -- -- --
Wild turkey (Meleagris gallopavo) -- -- --
Northern cardinal (Cardinalis
cardinalis) -- -- --
House finch (Carpodacus mexicanus) 1 2.1 0.9
Barn swallow (Hirundo rustica) -- -- --
American crow (Corvus brachyrhynchos) 4 8.5 3.6
Sharp-shinned hawk (Accipiterstriatus) 1 2.1 0.9
Brown-headed cowbird (Molothrus ater) 1 2.1 0.9
Canada goose (Branta canadensis) 1 2.1 0.9
Wood thrush (Hylocichla mustelina) -- -- --
Red-winged blackbird (Agelaius
phoeniceus) -- -- --
Cedar waxwing (Bombycilla cedrorum) -- -- --
Red-tailed hawk (Buteo jamaicensis) -- -- --
Green heron (Butorides virescens) -- -- --
Rock dove (Columba livia) -- -- --
Song sparrow (Melospiza melodia) -- -- --
Indigo bunting (Passerina cyanea) -- -- --
House wren (Troglodytes aedon) -- -- --
Willow flycatcher (Empidonax traillif) -- -- --
Black-and-white warbler (Mniotilta
varia) -- -- --
Northern waterthrush -- -- --
(Seiurus noveboracensis)
Wood duck (Aix sponsa) 2 4.3 1.8
Prairie warbler (Dendroica discolor) -- -- --
Mallard (Anas platyrhynchos) 1 2.1 0.9
Northern oriole (Icterus galbula) -- -- --
Black-crowned night heron 2 4.3 1.8
(Nyctiocorax nyctiocorax)
Rose-breasted grosbeak -- -- --
(Pheucticus ludovicianus)
Blue-headed vireo (Vireo solitarius) -- -- --
* Includes 8 specimens from which double--blood meals were identified.
([dagger]) Includes 11 specimens from which double--blood meals were
identified.
Table 4. Monthly prevalence of avian-derived blood meals in Culex
pipiens
Total American robin, Gray catbird,
Month avian n (%) n (%)
June 93 58 (62.4) 2 (2.2)
July 30 8 (26.7) 2 (6.4)
August 36 14 (38.9) 6 (16.7)
September 35 -- 9 (25.7)
October 4 -- 3 (75.0)
Total 198 80 22
House sparrow, Mourning dove, European starling,
Month n (%) n (%) n (%)
June 4 (4.3) -- 12 (12.9)
July 9 (30.0) 3 (10.0) 2 (6.7)
August 4 (11.1) 3 (8.3) --
September 3 (8.6) 7 (20.0) --
October 1 (25.0) -- --
Total 21 13 14
Other species,
Month n (%)
June 17 (18.3)
July 6 (20.0)
August 9 (25.0)
September 16 (45.7)
October --
Total 48
Table 5. Number and percentage of mammalian blood meals taken by Culex
mosquitoes collected in Connecticut 2002-2004
Culex pipiens *
% of mammal % of total
Species No. (n = 13) (n = 212)
White-tailed deer (Odocoileus
virginianus) 4 30.8 1.9
Gray squirrel (Sciurus carolinensis) 3 23.1 1.4
Northern raccoon (Procyon lotor) 2 15.4 0.9
Human (Homo sapiens) 1 7.7 0.5
Virginia opossum (Didelphis
virginiana) 1 7.7 0.5
Dog (Canis familiaris) -- -- --
Cat (Fells catus) 1 7.7 0.5
Eastern cottontail (Sylvialagus
floridanus) 1 7.7 0.5
Horse (Equus caballus) -- -- --
Striped skunk (Memphitis memphitis) -- -- --
Brown rat (Rattus norvegicus) -- -- --
Cx. salinarius ([dagger])
% of mammal % of total
Species No. (n = 64) (n = 111)
White-tailed deer (Odocoileus
virginianus) 43 67.2 38.7
Gray squirrel (Sciurus carolinensis) -- -- --
Northern raccoon (Procyon lotor) 2 3.1 1.8
Human (Homo sapiens) 2 3.1 1.8
Virginia opossum (Didelphis
virginiana) 4 6.2 3.6
Dog (Canis familiaris) 4 6.2 3.6
Cat (Fells catus) 3 4.7 2.7
Eastern cottontail (Sylvialagus
floridanus) 3 4.7 2.7
Horse (Equus caballus) 1 1.6 0.9
Striped skunk (Memphitis memphitis) 1 1.6 0.9
Brown rat (Rattus norvegicus) 1 1.6 0.9
* Includes 8 specimens from which double--blood meals were also
identified.
([dagger]) Includes 11 specimens from which double-blood meals were
also identified.
|
|
||||||||||||||||||||
Printer friendly
Cite/link
Email
Feedback
Reader Opinion