Journal of the American Mosquito Control Association, 10(4):556-564, lgg4 Copyright @ 1994 by the American Mosquito Control Association, Inc.

MOSQUITO AND ARBOVIRUS SURVEILLANCEIN CONNECTICUT,199 I_1992

THEODORE G. ANDREADIS,' PAUL M. CAPOTOSTO,' ROBERT E. SHOPE] AND SHIRLEY J. TIRRELL3

ABSTRACT. A surveillanceprogram for mosquito-borne arboviruseswas conducted in Connecticut following an epizootic ofeastern equine encephalitis (EEE) in horsesand dornestic birds during 1990. Mosquito trapping was done weekly using CO,-baited miniature light traps at l2 freshwaterswamp sites that were located mostly in the southeasternportion ofthe state.Trapping was conducted from June 27 toOctober 11, l99l andfromJune2toSeptember30, l992.Totalsof 7,435(1991)and13,912(1992) adult female mosquitoes representing2l speciesin 7 generawere collectedand assayedfor arboviruses. Virus isolateswere identified by ELISA usingreference antibody ofCalifornia encephalitis,EEE, Highlands J (HJ), JamestownCanyon (JC), LaCrosse,and St. Louis encephalitisviruses. Culiseta melanura was the most common speciestrapped each year, followedby Aedescanadensis, Aedes cinereus, ar'd Coquillettidia perturbans.The most abundant univoltine snowmelt specieswas Aedes abserratus. Three isolatespositive for JC virus were obtained from Ae. abserratus, Ae. canadensis (new state record), and Ae. cinerew (new staterecord) that werecollected from 2 different sitesin June ( I 992) and July ( I 99 I and 1992).Six isolates positive for HJ virus were made from Cs. melanura and one isolate from Ae. cinereus(new host record) collected in mid- to late September, 1992 from 3 locations. Basedon repeatedvirus isolations in this and other studies, high freld infection rates, and its relative abundance,Ae. abseftatusappears to be a principal vector ofJC in Connecticut.However, the prevalenceand importance ofJC as a human disease in the state are unknown. Culiseta melanura populations were abundant throughout the summer and early fall, and the availability of this potential mosquito vector does not appear to be a limiting factor for enzootic maintenance and subsequent amplification of EEE virus in presumed foci in southeastern Connecticut.

INTRODUCTION years and occurred coincident with major out- breaks involving humans and horses in neigh- Knowledge of mosquito-borne arboviruses in boring Massachusetts (Edman et al. 1993) and Connecticut is limited. Sporadic epizootics of Rhode Island (Gettman 1993). In response to eastern equine encephalitis (EEE) historically this renewed activity and in an attempt to obtain have occurred in horsesand flocks ofdomestic information on the current status of other mos- pheasantssince 1938 (seeAndreadis 1993 for quito-borne arboviruses in the state, we initiated review), and at least 2 California group viruses a 2-year surveillance program. The results of this that cause human disease(Jamestown Canyon investigation are reported herein. UCI and Keystone IKEYI) have been recognized since 1966(Whitman et al. 1968,Sprance et al. 1978,Main et al. 1979b).However, comprehen- sive surveillance of mosquito populations and MATERIALS AND METHODS arboviruses has not been conducted since Main Field collecting techniques: Adult female mos- et al. (1979a, 1979b\obtained several isolations quitoes were collected with dry ice-baited CDC of EEE, Highlands J (HJ), JC, and KEY viruses miniature light traps at 12 freshwater swamp sites from mosquitoes collected from 1969 through located in the towns of Chester, Cornwall, Fair- 1978. field, Haddam, Killingworth, Ledyard, North In October I 990, an epizootic ofEEE occurred Stonington, Salem (1991 only), Southington, among horses and commercial flocks of ring- Voluntown, Waterford, and Willington (1992 necked pheasantsat 6 locations in easternCon- only) (Fig. l). The majority of these sites were necticut (Andreadis 1993). These were the first in the southeastern portion of the state where confirmed casesof EEE in the state in almost l0 arbovirus activity had been reported previously (Andreadis 1993). These included all but one locale (Canterbury) where the confirmed EEE I Department of Soil and Water, The Connecticut were detected in l99O- The Wil- Agricultural Experiment Station, 123 Huntinglon Street, horse deaths following a single P. O. Box 1106,New Haven, CT 06504. lington site was added in 1992 ' Department of Environmental Protection, Field fatal EEE horse case in October 199 I . Most col- Services/Boating Division, Wetlands Restoration Unit, lection sites were characterized as mature hard- 5 I Mill Road, Madison, CT 06443. wood swamps dominated by red maple Acer ru- 3 Yale Arbovirus Researchljnit, Department of Ep- brum, Atlantic white cedar, Champaecyparis idemiology and Public Health, Yale University School thyoides, and eastern hemlock Tsuga canadensis- of Medicine,P. O. Box 3333,New Haven,CT 06510. 556 Dncpussn1994 Annovrtus Sunveu,I-lNcs rN CoNxecncur ))/

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Falrllold * !t t99O-SI Horse Deaths * lgl-52 nosgulto Survelllance Srtes

Fig. I . Distribution of equine cases of eastern equine encephalitis in Connecticut, l99G9l and location of mosquito and arbovirus surveillance sites, l99l-92.

Trapping was conducted weekly at each site otic, and antimycotic. The homogenatewas cen- (one trap per site) from June 27 to October I l, trifuged for l0 min at 1,500 rpm to clear the l99l and from June 2 to September3O, 1992. mixture of mosquitodebris. A 0.I-ml aliquot of Traps were set at the perimeter of the swamp each supernatantwas then inoculated into a 25- during the late afternoon and retrieved the fol- cm2 flask containing a monolayer of Vero cells lowing morning. Mosquitoeswere transportedto in growth medium and incubated at 37'C in 5olo the laboratory where they were cold anesthetized CO, for up to 7 days (Tesh et al. 1992). One on a chill table and promptly identified using the uninoculatedflask waskept asa nega.tivecontrol. keysof Darsieand Ward (1981)and Means(1979, The remainder of the supernatantwas stored at 1987). Specimenswere pooled by species,site, -70"C. The flasks were examined daily for cy- and collection date and then stored for l-3 days topathic effect.Ifcytopathic effectwas noted, the at -60qC pending virus assay.The number of cells were scraped from the flask and centrifuged mosquitoes per pool was variable and the max- for 5 min at 8,000 rpm. A cell lysateantigen was imum number was 100. then made from the cell button to use in the cell Rainfall data were obtained from 7 National lysate antigen ELISA (Ansari et al. 1993). The Weather ServiceClimatological Stations (Cock- isolateswere identified using referenceantibod- aponset Ranger Station, Falls Village, Groton, ies that were prepared in mice and provided by Jewett City, Norwich Public Utilities Plant, the WHO Center for Arbovirus Research and Shuttle Meadow Reservoir,and StaffordSprings) Reference.These included California encepha- that were located in the immediate vicinity of litis (CE) (BFS-283), EEE (Ten Broeck), HJ the collection sites.Moon phaseswere not mon- (8240), IC (61V2235), I-aCrosse (LAC) (Pro- itored. toype), and St. I-ouis encephalitis(SLE) (Parton) Virus assays: Each frozen mosquito pool was viruses. The antibodies were suftciently specific homogenizedin phosphate-bufered saline con- by ELISA so that end-point titrations were not taining 0.5ologelatin, 30olorabbit serum, antibi- necessaryto distinguish betweenrelated viruses. 558 Joumler, or rue AvErucnN Mosqurro Cor.nnol Assocr,o,rroN Vor. 10,No.4

Table l. Field-collected adult female mosquitoes tested for arbovirus from Connecticut. r99r-92. l99l r992 Species No. mosquitoes No. pools No. mosquitoes No. pools Aedes abserratus 48 l8 466 40 aurifer 57 8 canadensis 1,323 8l 2,6t4 135 cinereus 893 50 1,565 105 excrucians 20 9 29 9 sticticus I I 202 38 stimulans I I 49 29 triseriatus 267 44 207 43 trivittatus 163 l8 427 62 vexans 747 37 682 70 Anopheles punctipennis 221 59 t97 73 quadrimaculatus 26 l7 32 9 walkeri 43 6 Coquillettidia perturbans 713 50 1,249 64 Culex pipiens 522 33 232 63 restuans 288 45 698 84 territans 6 J 2 Culiseta melanura 1,974 r22 4,608 2t6 morsitans l8 t5 57 27 Psorphora ferox 175 23 467 33 Uranotaenia sapphirina 28 r6 28 l6 Totals 7,435 645 t3,912 t,r32

RESULTS September,however, were similar in each year: 25.5cm and 13.5cm in l99l and 21.7cm and Totalsof 7,435( I 99 l) and 13,912 (l 992)adult 10.7cm in 1992,respectivelY. female mosquitoes representing2l speciesin 7 The virus ELISA data are summarized in Ta- generawere collected,identified, and assayedfor ble 2. Three isolates positive for JC virus were arboviruses (Table l). Culiseta melanura (Co- obtained from Ae. canadensis,Ae. abserratus,and quillett) was the most common speciestrapped Ae. cinereuscollected in June and July from 2 each year, followed by Aedescanadensis (Theo- different sites(Waterford and Killingworth). The bald), Aedes cinereus Meigen, and Coquillettidia minimum field infection rate (MFIR) at eachsite perturbans (Walker). The most abundant uni- rangedfrom l:19 to l:100. Six isolatespositive voltine snowmelt specieswas Aedes abserratus for HJ virus were obtained from Cs. melanura (Felt and Young). and another from Ae. cinereuscollected in mid- Substantially higher rainfall amounts were re- to late Septemberfrom 3 locations in 1992 (Led- cordedin June (13.7 cm) and July (10.4 cm) of yard, N. Stonington,and Voluntown). The MFIR 1992than in June(4.1 cm) and July (5.6 cm) of for Ae. cinereusat the Voluntown site was l:25, 199I . Average monthly rainfalls for August and whereasthe MFIRs for Cs. melanuratangedfrom DECEMBER1994 Annovrrus SunvBn r.excr rN CoNNBcrrcur 559

Table 2. Isolatesof Jamestown Canyon (JC) and Highlands J (HJ) viruses from Connecticut mosquitoes in l99l-92.

Species Site Date Pool size MFIR' JC HJ Aedes canadensis Waterford 7-25-91 I l:l9 l:160 abserratus Killingworth 6-r2-92 24 l:40 l:160 cinereus Killingworth 7-ro-92 I l:100 l:160 cinereus Voluntown 9-23-92 9 t;25 =lloo Culiseta melanura Lrdyard 9-17-92 2 l:238 > l:160 melanura N. Stonington 9-23-92 l5 l:l2O > l:160 melanura N. Stonington 9-29-92 l9 r:r20 >1:160 melanura Voluntown 9-16-92 l5 l:132 >l:160 melanura Voluntown 9-23-92 ll r:r32 > l:160 melanura Voluntown 9-23-92 23 r:t32 > l:160 I Site specific minimum field infection rate (MFIR) for that mosquito speciesbased on total cumulative number of mosquitoes collectedat the site during the year.

l:120 to l:238, depending on the site. No isolates Large numbers of the univoltine mosquito le. positive for CE, EEE, LAC, or SLE viruses were abserratuswere collected during early June 1992 obtained in either year. (Fig. 3). The isolate of JC virus was obtained The weekly collection data of those mosquito from a pool of 24 females collected during the species from which virus isolates were obtained, 2nd week. A steady decline in adult abundance as well as those that have been incriminated in was observed thereafter. No valid comparisons previous EEE epizootics (Aedes vexans (Meigen) could be made with 199I collectionsas trapping and, Cq. perturbans), are shown in Figs. 2 and 3- was not initiated until the end of June in that Culiseta melanura was consistently collected year. throughout the entire sampling period of both Adults ofthe multivoltine mosqtitoesAe. can- years (Fig. 2). There were 2 peaks ofadult abun- adensis and Ae. cinereus generally were found dance in 1991. The first was observed in late June throughout the season(Fig. 3). Two periods of and the second in mid- to late September. The peak abundancewere observedfor both species, latter followed major flooding that was associ- mid-July and early to mid-September.Both spe- "Bob" ated with hurricane on August 18. Adult cies were particularly abundant during Septem- populations were generally higher during the ber. The 2 isolates of JC virus from each mos- midsummer months (July and August) of 1992, quito were made in mid-July and the isolate of but 2 peaks ofabundance again were observed. HJ virus from Ae. cinereusin late September. These occurred in mid-July and late August. The HJ virus isolates all were obtained from Cs. mel- DISCUSSION anura mosqrritoes collected during the last 3 weeks of September, 1992. The isolatesofJC virus from adult femalepop- Identical patterns of adult Cq. perturbans ulations of Ae. absetatus, Ae. canadensis,and abundance were observed each year (Fig. 2). Sub- cinereus reaffirm the presenceof this virus in stantial numbers were collected throughout July southern Connecticut. The first isolation of JC with peak populations occurring during the 2nd virus in Connecticut was made from a pool of and 3rd weeks. By mid-August, however, very 20 adult female Ae. abserratuscollected in the few adults were collected and none was detected central portion ofthe stateduring late June I 966 after September 9 and 15, 1991 and 1992, re- (Whitman et al. 1968).The virus was isolated spectively. again in July 1973 from a salt marsh species, Collections of the floodwater mosquito Ae. Aedescantator (Coquillett) (Spranceet al. 1978), vexans generally were limited to late August and and eachyear thereafterfrom I 975 through I 978 early September (Fig. 2). The largest catches were (Ae.abserratw: 15,Ae. cantator: l, Ae. vexans obtained during the first week of September I 99 I, : | , Cq. perturbans : I ) Main et al. I 979a).The 2 weeks after the hurricane. majority of these isolations were made from 560 Joumtel or urp Alr,rnnrcer Mosqurro Covrnol Assocu.noN Vor. 10, No. 4

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Jun Jul Aug SePt perturbans, arld Aedes vexans Fig- 2. Total weekly collections (all traps) of Culiseta melanura, Coquitlettida and isolates of Highlands J (HJ) virus in Connecticut ' l99l-92' DecEr,BER 1994 ARBovrRUsSunwrr,laNcp nl Cor.rNpcrrcrrr 561

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Jun Aug Fig. 3. - Total weekly collections (all traps) of Aedes abserratus, Aedes canadensrs,and Aedes cinereus and isolates of Highlands J (HJ) and Jamestownbanyon (JC) viruses in Connecticut. lggl_g2. 562 JounNar" or lue Ar"rnnrcet Mosqurro Corrrrnol Assocu^noN Vol. 10,No.4 mosquitoes collected in June, and all were col- isolations and low infection rates in theseareas, lected in the samegeneral vicinity (Killingworth Eldridge( I 990) hasexcluded Ae. canadenslifrom and Madison) as the pr€sentisolations. Our iso- his list of mosquito speciespossessing a signifi- lates from Ae. canadensisand Ae. cinereus rep- cant biological association with JC virus. Ac- resent new host records for JC virus in Con- cording to Eldridge (1990), there is evidence of necticut and add to previous isolations from Ae. a closeassociation between JC virus andAe. cin- cinerew in New York (Grayson et al. 1983) and ereus;however, virus transmission has not been Ae. canadensrsin Maryland, Michigan, and New demonstrated with this species (Heard et al. York (I-eDuc et al- 1975, Grayson et al. 1983, 1991),and our resultsindicate that althoughit Howard et al. 1988,Heard et al. 1990).James- is almost alwayspresent it is not normally abun- town Canyon virus has been isolated from Ae. dant during the late spring and early summer abserratus/punctor in Massachusetts(Walker et when JC virus apparently is active. al. 1993), Michigan (Heard et al. 1990), and The importance ofJC virus asa human disease Newfoundland (Mokry et al. 1984), in addition in Connecticut is unknown. To our knowledge, to Connecticut. there have been no serologicalinvestigations of The relative importance of eachof thesemos- humans, deer,or other potential vertebratehosts quito speciesin the epizootiology of JC virus in in this state. It has been suggestedthat JC virus Connecticut is unknown. The numerous isola- in an emerying diseasethat may be expanding tions from le. abserratusand relatively high field with the exploding deer populations in many infection rates( I :438 for a I O-yearperiod, I 969- regionsof North America (Deibel et al. 1983, 78 [Main et al- 1979a]and l:514 [overall] from Grimstad 1983, DeFoliart et al. 1986).Wide- l99l-92 in the present study) suggestthat this spreadhuman infection with JC virus occursen- speciesmay be an important vector, This view demically in Michigan and exhibits a distribu- is consistent with its feeding preference(Mag- tion pattern that closely parallels the estimated narclli 1977, Boromisa and Grimstad 1986) for distribution of white-tailed deer in that state white-tailed deer Odocoileusvirginianus, the pri- (Grimstad et al. 1986).Deer populationshave mary vertebrate host of the virus (Grimstad increasedsubstantially in southeasternConnect- 1983),and its closebiological associationwith icut during the last decade,and this growth has the virus throughout the upper midwest and been concurrent with an increasein the abun- northeasternUnited States(Eldridge 1990).In a dance ofthe black-leggedtick Ixodes scapularis recentlycompleted study, Walker et al. (1993) Say(formerly the deertick I. dqmmini Spielman, also implicated Ae. abserratus/punctor as a likely Clifford, Piesman, and Corwin) and the inci- epizootic vector of JC virus in western Massa- denceoflyme Disease(Anderson and Magnarel- chusetts.On the other hand, Heard et al. (1991) li 1980). Whether or not JC virus also is ex- were unable to demonstrate laboratory trans- panding in this region is subject to speculation. mission of JC virus by orally infected Ae. abser- Our findings suggestthat JC virus is enzootic in ratus/punctor that were field collected from an these regions;thus we feel further epidemiolog- enzootic focus located in Michigan. Although ical studies are warranted. vertical transmission of JC virus has not been The 6 isolatesof HJ virus from Cs. melanura demonstrated for Ae. abserratus,we also cannot collectedin mid- to late Septemberareconsistent rule out the possibility that this mosquito may with the ecologyof this virus in the northeastern serveas an overwintering reservoir for the virus, United States.Highlands J virus is maintained ashas been suggestedfor Aedes provocans (Walk- naturally in an enzootic cycle involving mos- er) (Heard et al. 1990) and Aedes stimulans quitoes and wild birds that inhabit wooded fresh- (Walker) (Boromisa and Grimstad 1986). water swamps.Peak periods of activity generally Aedes canadensli and Ae. cinereus also are occur during the late summer and early fall (Wil- known to feed on deer(Magnarelli 1977, Borom- liams et al. 1972, Main et al. 1979b, Srihongse isa and Grimstad 1986),and our study demon- et al. 1980).Most isolationsof the virus have strates that both speciesare multivoltine and been made from Cs. melanura, and this orni- omnipresent in freshwater swamps in Connect- thophilic mosquito hasbeen incriminated as the icut throughout the spring, summer, and early primary enzooticvector (Hayesand Wallis 1977). fall. Aedescanadensiswas among the most dom- Although the virus hason occasionbeen the cause inant species,and horizontal laboratory trans- of mild equine encephalitisin Florida (Jennings mission of JC virus has been demonstrated for et al. 1966,Hof et al. 1978),all virus-positive this mosquito (Heardet al. l99l). However,le. horse casesin Connecticut have been identified canadensisdoes not appearto play an important as EEE (plaque reduction neutralization tests), public role in JC virus transmissionin northeasternNew and HJ virus has not been recognizedas a (Hayes York (Boromisa and Grayson 1990)or Michigan or veterinaryhealth problem in this region (Heard et al. 1990), and based on limited field and Wallis 1977). 563 DecBurBr 1994 AREovIRUsSunwn-r-uce rN CoxxecrlcLrr

Highlands J virus was first isolated in Con- mon during epizootics but much less so during necticut in 1972 from a pool of Cs. melanura inter-epizootic periods (Morris I 988). mosquitoes collected in East Haddam during The absenceof EEE virus in mosquitoesfound September (Main et al. 1979b). The virus was in presumedfoci in southeasternConnecticut is subsequently recovered from 2 additional pools not fully understood.Our data clearly show that of Cs. melanura collected in August 1973 (Far- Cs. melanurapopulations are abundantthrough- mington) and October 1978 (Madison) during out the summer and early fall and that other the l0-year period from 1969 to 1978 in which potential epizootic vectorsfrom which EEEvirus 16,731 adult female Cs. melanurawere collected isolations have been made, specificallyAe. can- and assayed for arboviruses (Main et al. 1979b)' adensisand Ae. vexans,also are locally abundant No additional isolations of HJ virus were ob- during Septemberwhen EEE virus activity typ- tained from 140,9 l5 adult female mosquitoes, ically occurs.Thus, the availability of a suitable representing 28 species in 8 genera, in that same mosquito vector doesnot appearto be a limiting study. This included more than 5,0OOAe. ciner- factor. In this regard, Cq. perturbans does not eus. We believe our single isolation of HJ virus appearto be a likely vector ofEEE in theseregions from 1,565 adult female Ae. cinereus collected ofConnecticut becauseofits low abundancefrom in 1992 represents a new mosquito host record mid-August through September.It has been sug- in the eastern United States. Aedes cinereus is gested (Wallis and Main 1974) that Connecti- known to feed on birds as well as mammals cut's numerous suburbanforests and woodlands, (Magnarelli 1977); however, its vector potential which comprise more than 600loof the state(An- for HJ virus would appear to be limited based dreadis1993), provide a sylvanswampland ecol- upon the low number of virus isolations. ogy in which wild birds hosts and mosquito vec- Although EEE and HJ viruses can be active at tors are widely dispersed. Consequently, there the same time in the same location, HJ virus is may be an insuftcient focus of infected birds usually more prevalent that EEE virus and ap- during most yearsto provide for an annual build- pears in mosquitoes earlier in the season in Mas- up of infection to detectablelevels in local mos- sachusetts swamps (Edman et al. 1993). In up- quito populations. However, whether EEE is re- state New York, there appears to be an introduced from time to time by migrating birds unexplained alternation ofthe 2 viruses in suc- or overwinters as a chronic infection in resident ceeding years (Howard et al. 1988). Thus the passeriformsremains unknown. detection of HJ virus in Cs. melanura popula- tions can, at times, be useful in predicting sub- ACKNOWLEDGMENTS sequent EEE virus activity in some areas (Edman We acknowledgethe technical assistanceof B. et al. 1993). Long-term surveillance would be Adams,M. Gere,R. Iannuci,G. Krevis, C. Mos- required to determine whether or not HJ would er, D. Pugh, D. Shaw, F. Shaw, E. Spencer,and be a reliable predictor of impending EEE activity S. Waltman. Virus identification studies were in areas of southeastern Connecticut. supported in part by grants NIH AI 10984 and The lack of EEE virus isolations from Cs. mel- DOD DAMDtT-90-Z-O020. anura or other recognized mosquito vectors in the present investigation was not surprising, even REFERENCESCITED the survey was conducted during a time though Anderson,J. F. and L. A. Magnarelli. 1980. Verte- when the virus presumably was active (i.e., con- bratehost relationshipsand distributionof ixodid firmed horse deaths occurred during 1990 and ticks (Acari: Ixodidae) in Connecticut,USA. J. Med. l99l). Although widespread epizootics of EEE Entomol. 17:314-323. virus have occurred historically among horses Andreadis, T. G. 1993. Epidemiology of eastern and domestic birds within the state since 1938 equine encephalitis in Connecticut. J. Fla. Mosq. Control Assoc.64:97-103. (see Andreadis 1993), there have been no con- Ansari,M. 2., R. E. Shopeand S. Malik. 1993. Eval- firmed cases of EEE in humans. Furthermore, uation of Vero cell lysate antigen for ELISA of fla- despite extensive surveillance during epizootic viviruses.J. Clin. Lab. Anal.7:23V237. periods of the mid-1950s (Wallis et al. 1958a, Boromisa,R. D. and M. A. Grayson. 1990. Incrim- 1958b, 1960) and early (Main et al. 1979b), only ination of Aedesprovocans as a vector of Jamestown 5 isolations of EEE virus have been obtained Canyon virus in an enzootic focus of northeastern from mosquitoes collected in Connecticut, 4 from New York. J. Am. Mosq. Control Assoc.6:50,1-509. Boromisa, R. D. and P. R. Grimstad. 1986. Virus- Cs. melanura (Main et al. 1979b'l and one from vector-host relationships of Aedes stimulans and Ae. vexans (Wallis 1960). 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America,north of Mexico. Mosq. Syst.l(Suppl.):l- Magnarelli, L. A. 1977. Host feedingpatterns of Con- 3l 3. necticut mosquitoes (Diptera: Culicidae). Am. J. DeFoliart, G. R., D. M. Watts and p. R. Grimstad. Trop. Med. Hyg. 26:547-551. 1986. Changing patterns in mosquito-borne arbo- Main, A. J., S. E. Brown and R. C. Wallis. 1979a. viruses.J. Am. Mosq. Control Assoc.2:437-455. Arbovirus surveillancein Connecticut II. California Deibel, R., S. Srihongse,P. R. Grimstad, M. S. Mahdy, serogroup.Mosq. News 39:552-559. H. Artsob and C. H. Calisher. 1983. Jamestown Main, A. J., A. L. Smith and R. C. Wallis. 1979b. Canyon virus: the etiologic agent of an emerging Arbovirus survelliance in Connecticut I. Group A human disease,pp. 313-325.In: C. H. Calisherand viruses. Mosq. News 39:544-551. W. H. Thompson (eds.).California serogroupvirus- Means, R. G. 1979. Mosquitoes of New York. Part es. Alan R. Liss. Inc.. New York. I. The genusAedes Meigen with identification keys Edman,J. D., R. 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