This pdf file contains pages excerpted from Technical Bulletin 61 that relate to Angiostrongylus cantonensis, the rat lungworm, its rat (p. 80–84), its intermediate mollusk hosts (p. 24–26), and information on angiostrongylosis disease in humans (p. 31–36). The entire 138-page bulletin is available as a pdf file (~37 MB) at the community home page of the College of Tropical Agricul- ture and Human Resources, University of Hawaii at Manoa, on ScholarSpace: http://scholarspace.manoa.hawaii.edu/handle/10125/1877 24 HAWAII AGRI C ULT URAL E XPERIMENT STATION

MOLLUSKS OF PARASITOLOGICAL IMPORTANCE IN HAWAII

M OLLUSK ( NATURAL SIZE) LO CA TION FOUN D Ii\IPORT A j\;C E

SNA ILS

A ctiatina [utica On land Intermedi ate host for th e rat lungworm , Angiosirongylus can tonensis, which produces cerebra l ang iostrongy losis (pa rasitic eosinoph ilic m en ­ ingoen cephali tis) in m an (see pp, 31- 36).

Bradv boeno: similaris O n land Interm ediate host for: (a) th e cat lungworm s, Analilaroides rostro tus a nd A elurostrongy lus abslrusus; (b) the ch icke n cecal nuke, Pos tharmostomurn gallini nn; (c) the rat lung­ wor m, Angiosirongylus can tone nsis, which produces cere bral ang iostro ngylosis (paras itic eosinophilic men­ ingoencephali tis) in m an (sec pp. 31-36).

Fassaria oll ula On banks of fresh­ Intermed iate host for the wa ter strea ms catt le liver nukes, Fasciola and swamps gigan tic a and F. hepatica. I' AR ASIT IC INFECTI O '\iS O F M AN A ND A'\i I MALS IN H A WA II 25

MOLLUSKS OF PAR ASITOLOGICAL IMPORTANCE IN HAWAII

~ IO LLUSK (NATURAL SIZE) LO CATIONF O UN D I MPORTANCE

L itt orina p in tado On marine roc ks Interrn ediate ho st for the bloo d fluk e, Austvo bilhavzia uariglandis, of certain fish­ eating b irds. T he larvae (cercariae) emerging from th e sn ai ls are poten ti ally ab le to prod uce derma titis in man .

Opeas [auanicum O n Jan d In termediate host fo r th e ra t lu ngworm, Angiosirongylus can to nensis (see A chai ina [u licay.

Pseudosucciueo. O n banks of fr esh­ (Same as Fossaria ollu la) columella water strea ms and swa mps

St enomelania 1n Iresh-wa tel' In ter mediate host for the n ewcornbi st rea ms fo llowin g intest in al fluk es: (a) Ccntrocestu s form osan us in th e night heron and ra t; (b) H aplorchis ),olwgaw ai in the n ight heron; (c) Stellant­ cha smus [alcatus in the cat, dog, ma n , and rat. Also in ter­ medi ate host for th e eye-fluke, Pliil oplittialmus gra lli, in the Ha waiian coo t, a nd also capable of develo pi ng in mamm als.

Subulina octona On land (Same as B radybaen a similariss 26 H AW AII AGRIC UL T URAL E X PERI MENT ST ATION

MOLLUSKS OF PARASITOLOGICAL IMPORTANCE IN HAWAII

M OLLUS K (NATURA L SIZE) LOCAT IO N FOUND 1~ I P ORTA i'\ C E

T'hiara gU/'ll i[em In fre sh-wa ter In termedi ate host for th e strea ms follo wing intestinal fluk es: (a) Cen iro cestus [orrnosanus in th e ni ght heron and ra t; (b) Haplorch is taicliu i and H . yo lwgawai in th e night heron; (c) Stellantchasrnus [alcatus in the ca t, dog, ma n, and ra t. Also in termedi ate host tor th e eye-fluke, Philopht ha lmus gralh , in the Hawaii an coo t, and also ca pa ble of developing in mammals. Potential host for th e lung fluk e, Paragonim us ioestermon i, in m an .

S I.lIeS

Devo re ms 10em: On land a nd l ntermed iate host tor th e rat vegetatio n lun gworm , A ngiostrongylus cantonensis (see Aehatina JJ fulica) . l 'c ro n i cc lla altc On land and you ng Intermediate h ost lor th e rat o nes occasiona lly lungworm, A ng iostrongylus on vegetatio n canionensis (see A cha tina [ 'IIlica). PAR ASITI C I:-lF ECTI O NS OF M A l': AN D AN I ~ rAL S I N H AWA II 31 in a child in the contine n tal U nited States (De n t et al ., 1956); conse q uen tly, th erefore, cere bral toxocarosis m ay gi ve ri se to eosinoph ilic meningoen ­ cephali tis. In 1961, the rat lungworm, A ngiostrongy lus cantonen sis, was recovered in Hawai i at an on the bra in o f a Filipino with a hi story of eosino­ phili c m en ingoen cephalitis (Rosen et a!., 1961, 1962). This finding fol­ lowed the d iscover y by Ash (1962b; see Parasites of R at ) of the ad ult stage of A . cantonensis (fig. 3 1d) in th e lu ngs of loca l rats, and confirme d the specu­ lati on originall y m ad e by Alica ta (1961, 1962a) th at th is par asite m ay be i he ca usative age nt o f eosinoph ilic meni ngoencepha litis in th e Pacific (see also Alica ta and McCarthy, 1964). A case of this di sease, also referred to as par asiti c meningoencephalitis and cere bra l angiostrongy losis, occurred in a J apan ese laborer in H awaii following ingesti on o f two ga rde n slugs, Veron i­ eel/a ali e (see H orio and Alica ta, 1961). A . cau to nens is is normall y a pa rasite of rats and util izes mollusks (p p. 2cl ­ 26) as in termed iat e hos ts (see Par asit es of R at). Land planarians (C eo-p lana scp tc m li neata s in H awa ii, and fre sh -water p rawns (M acrobracl,,'u m sp.) and land crabs in other Pa cific areas, h ave been fou nd to serve as parateni c or tran sport hosts far the infectiv e lar vae (Alicata and j\JlcCa rth y, 1964); experi­ mentall y, p igs and calves h ave also been found to serve in th at capaci ty (Alica ta , 1964b ). H um an in fecti on with A, cau tonensis most lik ely occurs as a resul t of eat­ ing uncook ed food (fig. 3) con ta in ing in fecti ve larvae of the parasite. Eating habi ts and customs o f people may p lay an importan t pa rt. In Tah it i, th e common occurre nce of eosinop h ilic meningoen cep haliti s h as been traced to the customary hab it o f ea ting raw prawns, incl ud ing, possibl y, "taio ro .' The latter consists o f grated cocon ut to wh ich is added p rawn juice, prepared by grinding the stomach and surro und ing portions of the p raw ns in fresh watel' (AIicata and Brown, 1962). 1n T h ailand, the d isease is beli eved to be acq u ired as a resu lt of ea ting the large amph ibio us snail, Pila am -p u llacca (see Punyagupta, I96·l). The flesh y head-foot part 01' the sna ils is cut and then eithe r d ip ped in boiling water or sto red in an icebox to keep it fr esh. It is then eaten after being chop pe d int o small pieces, seaso ned with lime j uice, and mi xed with vegeta bles. I n New Caledo nia and Hawai i, whe re eosinoph ilic meningoen cephali tis occ urs sporad ica lly, it is p ro babl y acq u ired throu gh the acciden tal in gestion of an in Iected smaII garden slug, or a carrier host such as a land plan arian, wit h con ta minated salad gree ns (Alica ta , I963a; Mead , 1963). F ur thermore, in som e are as, human in fection m ay pos­ sibly tak e place from eating raw land crabs (Alicata, 19640) and impro perly cooked li ver or othe r in tern al org ans of swine or calves (Alica ta, 1964b). T hese in th eir foraging habi ts ar e believed to in gest live mo ll usks. <.>0 CARRI ERS tgL~~A t':L-lN FECTlOti K)

CALF~' " <:'. : .: .' .: " ~ ; ' \ / ', ' ' I ill ~ IN F ECTIV E L ARV A E , WH ICH ARE / I I N GE STE D BY TH ER AT . M I GRA T E TO ~ I PIG lfHt.· I T HE BRA IN AN D RE ACH YOUNG A DULT - I . ; -.. I /P' , '\ HOOD I N F OUR WEEKS THE N THEY \ I / 'I M IGRATETO TH E PUL MON ARY ARTERIES 1 AN D A FT ER T WO M ORE W E EKS HATC H I N T H E 1/ PRAW » :> I S TART L AYI N G E GGS , A N D THE Y OU NG I ~N I <, ~" :c I A ,- :> I / ?~ DI GES TIVE T RACT - -t>BR A IN ~ :> n II ~ ( , CRAB /1 :> FIRST -STAGE L A R VAE I NFECTA I ...-v'l . ' / I C'l ~ ~ M OLLUS CAN I NTERM ED I ATE HO ST I I o AND R E A CH THE I NFECT IV E ( TH IR D) 1/ I c STA GE I N A BO U T T WO WEEK S . tj ' PL ANAR I AN 1 c: / l'- " / 1 ~ :> / -> I r' M X "<, ? _ VEG E TA T IO N A ...... / ~ ~ / 1I M'" :- '2<, /' -: ----b,.. ':;11'. / / ~ - ~ / I . ' - ::; 7"' ---- "_" ..:wo. ~ ~ / M - -- Z --- / .., -- -- J .E.A . ------~ ..,:> (5 F IGURE 3. Life cycle of the ra t l ungworm , Angiostrongylu s can tonensis, and possible aven ues of human infection. (O riginal.) Z PA RA SITIC I N F ECTI O~ S OF :\I A N A ~D AN D'fALS 11\ H AW AII 33

Experimentall y, livin g lar vae of A. can ionensis h ave been found in th e stom ­ ach wall, li ver, lungs, and splee n of pigs and calves 2 weeks after infection . In th e pi g, however , th e lar vae were found enca ps ulated and dead in th e above organs 5 weeks after infection. The com pa ratively ea rl y encapsula tion of th e lar vae, therefore, appears to m in imize th e importan ce of th e pi g as a carrier host. Experimentally, th ese larvae h ave not been found to mig ra te to the volun tary m uscles of pigs or calves (Alica ta , 1963c) 1964b) . To wh at ex ten t pigs and calves are infected with larvae of A . can tone nsis under natural cond itio ns and thus serve as sources of human in fecti on rem ains to be determined. Eos inoph ilic men ingoencephalit is is a syndrome ch aracterized by th e presen ce of eosinoph ils in the cere brospina l fluid. In m an this syndrome h as at times been noted in connect ion wit h cases of no nhelmin th ic and hel­ minthic infections involving the cen tral nerv ou s system. N onhelminthic infecti on s have been obs erved in some cases of cere bra l tumors, epide m ic cerebrospinal me ning itis, neurosyphilis, purulent m eningitis, an d tubercular meningitis (Kaczynski, 1936). H elminthic infecti ons in clude cer ebral angio­ strong ylosis (H orio and Alica ta , 1961; R osen et al., 1962;Alica ta, 1963a), cere b ra l (Kulkov, 1930), cere bra l ech inococcosis (Applebau m and Wexberg, ]9'14), cerebral paragonim iasis (U ematsu and Shi ozaki, 1935; N ono rn u ra, 1941), and cere bra I sch istosomiasis (Cas ta igne et al., ]959). In the Pacific Basin , cases o f eosinoph ilic men ingoencep hali tis have been rep orted from Micro nesia, Pol ynesia, and Me lanesia . A few add itional cases have bee n reported from J apan ( onomura, ]941) an d the Philippines (Sison et al ., 1951). In Southeas t Asia , cases h ave occurred in T haila nd (Pu nyagup ta, 1964) and Su ma tra (Sm it, 1962). Laboratory and field evi­ den ce suggests that A . can tone nsis is in m ost cases th e causative age n t of eosino p hilic men ingoencepha li tis in H awaii and other Pacific islands. T h is evidence includes: (a) recover y of young ad ult A. can tonensis from man in two cases of eosino p hilic m eningoen cephalitis (N om ura and Lin, 1945; R osen et al., 1962);(b) capability of the larvae of A . canionensis to tr avel to th e central nervou s system of simia n primates and to give rise to eosinop h ilic meningoen cephalitis (Alica ta, 1962a; Alicata , Loiso n, and Ca­ vallo, ]963; Weinstein et al., 1963); (c) record of two human cases o f eosino ­ philic meningoen cephalitis follow ing th e willful in gesti on of raw slugs from endemic areas (H orio and Alica ta, 1961; Ali cata , 1963a); (d ) record of a human case of the di sease in Hono l ulu foll owing the in gesti on of six raw g iant Africa n sna ils, A chatina [utica (see Mookini, ]96-J. ); (e) presence of lungworms amo ng rats in all the Pacific islands (fig. 4; see also Parasit es of R at ) in whi ch eosinoph ilic men ingo encep halitis has been re corded, namely, Cook Islan ds (Alica ta and :McCarth y, 1964), Fo rmosa (Nomura and Lin, 1945), G uam (Lo ison, 1963), H awai i (Horio an d Alicata , 196] ; R osen et al., .." v· '. ~ ",: ..._._. v .J.­ '1 ~

Tropic of Concer .. '"'100'"• Hawaiian !!. ; . ~ Guom . ... Truk Is. . ;. ,:' . .•... •~ ..," .If. ~',~: :.

~ ,~ . ' .

New Hebr ides [i. ~J ~ . ~ . ..~t . ,,"l - ~ . donia ."', .. " . .~: Cook Is," " . .. ~ ~'~lOYal ty Is. . ----..'. .'{!!hi.ti Tropic of Capricorn

)J II d I tf

F IGURE 4. Geogra phical d istribu tion of th e rat lungworm. Angiostron gylus can ton ensis, in th e Pacific islan ds and Southeast Asia (indicated bv slars) . and its relationsh ip to the d istribution of eosino ph ilic me ningoen ceph alitis in man (underscored).(See text , pp . 31- 36.) PARASITIC I :>I F ECTI O i\:S OF M A N AN Il A N Ii\ IALS 1:\ HAWA II 35

1962), l\ew Caled onia (T ruben, ]952), N ew H eb rides (Loison, ]963), Po­ nape (Ba iley, 1948), Saipan (All ison, 1962), an d T ahiti (Fran co et al., 1960 ); (f) absence of the di sease in areas o f the Paci fi c where th e ra t lu ngworm is not known to occur, namel y, Fi ji, Samo a, Tonga, and W allis (Lo ison, ]963); (g) h igh incid en ce of eosinop hilic meningoenceph alitis in Tahiti correla ted with th e freq ue nt cons umption of raw prawn s, 4 percen t o f which have been found in fected wit h th e lar vae of A. cau tonensis (see Alicata and Brown, 1962); and (h) wides pread in cid en ce of the d isease in parts of T ha i­ land correlated wit h cons umptio n of in suffi cien tl y coo ked amph ibiou s sna ils, Pila am.pullacea (see Punyagupta, 196'1). The cause of eosinophilic m en ingoen cephalitis reported from J apan and possibly from th e Philip pines, where A . can tonensis is not kn own to occu r, in all p robability is d ue to cerebral paragon imiasis. In J apan, Uerna tsu and Sh iozaki ( 1935) rep orted a pl eocytosis of 1,44 1 cells per cubic mi llimet er , consisting of practi call y all eosino ph ils, in th e cerebrospina l fluid of an indi­ vid ua l wh o showed meningeal irritation s, cloud iness of both lu ngs in the X-ray examination, and numerous Paragonimus eggs in th e sp u tu m. I n the same wa y, N ono mu ra (194 1) reported a pl eocytosis wit h 98 percen t eosino ­ phils in the cerebros pina l fluid of ano ther patient in J apan . Alt hough no fluke eggs wer e found in th e sp u tum of th is patie n t, Nono mura conclude d that the pleocytosis was most likel y produced by cerebral . Furthermore, the sporadic cases o f eosinoph il ic meningoen cephalitis, which have been rep orted from E urope and N or th and Sou th Ame rica, wh er e A, caritonensis is not kn own to occur, ar e poss ibly ca used by one or more spe­ cies of helminths which occasionally in vad e the cen tra l ner vo us system (Smit, 1962). Of importance in this connec tion is th e finding of eosino ph ilic infil­ tration of the meninges, resulting from lar val infection of T ox ocara can is) wh ich ha s been observed in a ch ild in the con tine n tal U nited States (De nt et al., 1956). E tio logicall y, however , infect ion wit h larvae of T ox ocara occu rs most commo nly in young ch ild ren, whereas eosinoph il ic meningoencepha­ litis in the Pacific area occurs ch iefly am on g adults. Of interest is the a ppa re nt ab sence o f A . can ton ensis amo ng rats in Fiji, the Philippines, Samo a, Tonga , an d "Vallis Islands, whose clima tic cond i­ tion s and fau na are ge ne ra lly sim ilar to those of other Pacific isla nds in wh ich th e parasite occu rs. In all probability, th is cond it ion poin ts o ut that th e pa ras ite is a recen t immigrant to th e Pacific islands an d one wh ich as yet has not becom e more wid ely di str ibuted . Its origina l sou rce of dispersal appea rs to be Eas tern As ia. It was first re corde d from Ca n to n, C hi na, by Chen in 1935, a nd in 1937 it was reported by Matsumoto an d Yokogawa fr om For­ mosa. It appea rs to h ave gra d ua lly spread to variou s Pacific islands eithe r throu gh im portation of infected mo llusks or in fected rat s. This has probably been bro ught about by recen t increased commercial and mi litary ship ping 36 HAWA II AGRIC ULTURA L E X PER IMENT ST ATION operatio ns, esp ecially d uring World W ar II, fr om Eastern Asia to various Pacific ports. Further evidence of th e recent di sp ersal of th e rat lungworm in the Pacific region appears to be th e recent occ urrence of eosinop hilic meningoencephalitis in the P acific islands. T his syndrome was first noted in Formosa in 1944 (Nomura a nd Lin, 1945), Ponape in 1947 (Bailey, 1948), New Cal edonia in 1951 (Tru bert, 1952), an d T ahiti in 1958 (Franco et al., 1960). As indicated above, A. can tonensis was first dis covered in East Asia in 1935. Furthermore, the first case of eosinop hi lic meningoence p halitis in th e Pacific was reported fr om Form osa in 1944. In this connectio n, it is of im­ po rtan ce to note that th ese findings followed shor tly after the in troduction of th e gia n t Africa n snail, A chat ina [ul ica, in th e areas. A . [ulica is an ideal intermediate h ost of A. can tone nsis. According to Me ad (1961), during th e ninet eenth cen tury, th e ach a tini d snails became di spersed from th eir East Afr ican home to Sou the as t Asia and from there to East Asia a nd the Pacific islands. T hey were first found in Ma lay a in 1911, Indonesia in abou t 1930, Ch ina in 1931, Form osa in 1932, the Maria na and Hawaiian Islands in 1936. T hese data point out that A. [utica mi ght have imported or assisted in th e spread of the ra t lu ngworm in Asia a nd in th e P acific isla nds . If this is true, it is possible that th e origina l habitat of th e parasite is East Afri ca, th e same as that of A . [ulica. Altho ug h A . [utica is not known to occ ur in Aus­ tralia, New Ca led on ia, or Tah it i, where A . can lonensis is now fou nd, it is possib le th at th e parasite was im ported in th ese areas th rou gh infected lan d mollusks or in fected rats from Southe ast Asia 0 1' ] nd onesia afte r it had be­ come establ ishe d th er e. T he p rob ability tha t A. can tonensis mi ght have originated from East Africa or nea rby areas is being further in vestiga ted by the au tho r. * The geog rap hical area in which A. canionensis is presently known to occu r in man and ro dents is li mited to th e tropical belt wh ich ex te nds ap­ proxim a tely from th e Tropic of Cancer (23 0 N or th la titu de) to th e Tropic of Caprico rn (23 0 Sout h latitude) (fig. 4), and from T hailand (100 0 East lon gi tude) to th e island of Tahiti (150 0 W est lon gitu de). T h is a rea is char­ acterized by tro pical and subtropical clim ate, rnodera te to h eavy ra infall , and considerable veget a tion . All th ese factors are hi ghly con duc ive for th e propagation and sp read of mo ll usk s and roden ts.

TAP EWORMS Most cases of tap eworm infection th a t h a ve occurred in Hawaii probably represen t in fection s acquired elsewh ere . In a survey carried ou t b y Powers

" Afte r thi s manuscript was submitted for p ub lication, Dr. Kenich i Nish im ura and Dr. Ma riano G. Yogor e rep orted to the wr iter of find ing Angiostro ngylus can tone nsis am ong ra ts in Manila. T he writer has also found A . can ton ens is in th e lun gs of rats on th e isla nd s of Mauritius, Ma dagascar, and Ceylo n. 80 H A W AII AG R IC ULTURA L £ XPER I;vI E:-lT STATION

ARTHROPOD S

T he m ite, Psorop tes eq u i cu niculi, which ca uses ear man ge, is th e most im port ant external pa rasite affect ing dom estic rabbits. It is as troublesom e in H awa ii as in ot her areas . T he in flammatory reacti on prod uced by the mite ca uses a b rownish di scharge which cakes inside of the ea rs. Affected an ima ls freq uen tl v sha ke their head and tr y to scra tch their ears with th eir h ind feet. T he m ite, 'volocd res cati cunic uli. has a lso been collec ted from th e face of' the rabbi t ( Haramoto, 196 1). M ires are transm itte d by con tact.

RAT

P ROTOZOA

The blood fl agell ate, T rypmlOsnrna. leioisi, has been reported fr om wild rats inhabi ti ng a gu lch in the H umakua D istr ict of th e islan d of H awaii (Ka rtman, 1954). T he in cidence of in fection among the fi eld rat, R attus ex u­ lans, was said to be almost four times that of R . noroegicus and abou t two ti mes th at o f R . rat tus and its subspecies. On the basis of epizootiological evide nce, it was suggested tha t the rat fl ea, X en op svl! a uexo bilis hn ioai ien sis, is the principal in termed iate host. TrY/Jal/oso." w conorh ini, a blood parasite of an unknown vert ebrate, h as been reported from th e red uviid b ug, T ri­ at om a rub rolasciaia, collected under a ch icken coo p on the island of Oahu (Wood, 1946). T h is par asite has bee n gro wll ex perime nta lly in rats and mice, and in cuiture med ia (Joh nson, 1947).

RO UND W ORM S

.ln a survey of parasites of rats in H on olu lu, the foll owin g species and per centages of roundworms were fou nd (Ash, .l962b): sto ma ch worm s, Con­ p,ylonema u eoplasticum (fig. 3 1a), 53; Pliysalop tera muris-braziliensis (fi g. 31c), 37; in testina l worms, H eteraki s spurnosa, 46; Nippostro ngyl us brasili­ ensis, 17; Strongy loid es ra ui, 17; Syp ha cia ob uelata, 44; urinary bladder­ worm , T'rich osomoides crassicau da (fig. 31b) , 17; Iun gworm , A ngiost rongylus cantonensis (fig. 3 1d ), 12; li ver cap illarid, hepatica (fl g. 3Ie), 28, T he intesti nal capi lla rid , Capillar ia. trauera e, and th e aca nthocephala n, M oniliiormis monili!armis, were also rep orted. A fa tal case of C. hepat ica infection h as also been reported from a ch ild in H awaii (see Parasit es of Man). I n add ition to th e above, T viclnncll a spira lis ( fi g. 32a) occurred in 2.7 percen t of the rats exam ined [rom the island of H awaii, and in 0.09 per cent [rom th e islan d of Mau i (Alicata, 1938e). No trichin ae have been fou nd among rats on the islands of Oah u and Kauai, T h is par asite occurs in man and swine in Hawaii (see Par asit es of Ma n, and Swine ). P ARASIT IC I NFECTI O NS OF MAN A;\ID Ai\ L\-IA LS 1;\1 H AW A I I 81

f lCUR E 31. Pa rasi tes of the rat : a, ad u lt Gongylo llema neoplasticurn; b, ad ult bladder­ worms, T ricn osom oides crassicauda; c, ad ult sto ma ch worms, Ph vsalopterr: muris-brasili­ ensis; d, ad ult l un gworms, Angiostrongyll.l s can ionensis; e, liver sho wing clu sters (an· ow) of eggs a nd ad u lts of Capillaria hepatica; f, liver sho wing (an ow) encys ted infective la rval stage (stro bilocerclIs) of th e ca t ta peworm . f-fyda tigera taen iaelormis. All na t ural size. ( Or iginaL) 82 H AWAII AGRICULTURAL EXPERIMENT STATION

FIGURE 32. 0, I nfecti ve la rvae ot T richinella spiralis en cysted in the d iaphragm of rat , hi gh ly magni fied : b, ad u lt ta peworm, H ym enole-p is n ana, na tu ra l size; c, ad ult tapewor m, Hym enolepis diminu ta, na t ural size. (O rig inal.)

Of th e above roundworms , Gon gy lon ema neoplastic uni utili zes cert ain cockroach es and beet les as intermedi ate hos ts. T h ese in cl ude Blatella gel"­ monica, Peri p lan eta americana, and T'en cb rio m olitor (see H all, 1929), all of which occur in H awa ii. According to O 'Dea ( 1964), the stoma ch wo rm, Plrysaloptera muris-brasilieusis , h as been experime n tally det ermin ed to util ize the following arthropods as in tcrmed iate hosts: (O rder: Co leoptera ) Dcrmestes uu lpinus, T'en ebro ides ncrui, and T'ribolium castane urn; (O rde r: Orth o ptera) N au .phoeta cinerea and Perip lan eta am ericana. T h e lungworm, Angiosirongylus can ione nsis, u tilizes a mollusk as inter me­ diate host (pp. 24, 26 and fi g. 3).T he development of th is parasite to the in ­ fecti ve or th ird-larval stage (fig. 33e) in th e garden slug , Deroceras laeue, was [i rst described by Mackerras and Sandars ( l955) . These wr iters also traced the develop men t of the parasite in the rat host and determined th a t during larva l developmen t it in vad ed th e brain and p roduced d ilation of the m en ingea l vessels and leucocytic infiltration . T he rat lu ngworm was first round in Ha­ waii b y Ash in Novem ber, 1960 (Ash, 19620). Subseq uently the gian t African snail, Achatina [utica, the gard en snails, B rady baena similaris and Subulina o Ct011O , an d th e ga rden sl ug, Veronicella alte, were fou nd to be suitable ex- r lC UR E 33. Larvae of A ngiostrongylu s can ion ensis: a, first-stage la rva recovered fro m feccs of ra t, X300; b, full-grown first-stage la rva from snail, X300; c, second -stag e larva enc losed within cuticle of first mo lt from sna il, X300; d, third-stage larva enclose d within cast cu ticles of th e first and second molt from snail. X300; e, third-stage la rva co iled in th e m usculature of snail, X300; f, a ntcr ior end of third-stage lar va showing th e cha racte ristic sclero tized sto ma torhabd ions in b ucca l cavi ty, X640. (n- e, Origin al; f, af ter Alica t a, 1962, co urtesy of Cana dian Journ al of Zoology. ; 84 H AW AII AGR ICULTURAL EXPE Rl l\ lENT ST ATION perim ental in term ed iate hosts (A licata, 19G2a). In clud ed also is the garde n sna il, Opeas javaniclI1 l1 , and possibly other members of this ge n us. Accord ing to Kon do ( 196!), rnalacologist, Bishop M useum, seven spec ies of O!Jeas occur in H awaii as follow s: O. beck ian urn , O. claou linunt, O. goodall i, O. [auani­ CII 11/., O . m auriiianurn, O . o-parattum, and O . opella. T he fresh-wat er sna il, Fossaria ollu la, was a lso found to be a suitable experime ntal host (Alicata an d Bro wn, 1962). Of the above mollu sks, A. [ulica, B . similaiis, S. octona, o. [auanicu rn, V. al tc, and D . laeue have been found natu rally infected with th e larvae of the ra t lu ngworm.T he land planari an, Geo p lana sep temli­ neat a, in Hawaii a lso frequen tly harbors the inf ecti ve lungworm la rvae (Ali­ cata, 1962n). Pl an arians, however, serve on ly as paraten ic or transport hosts and acq uire the larvae Irorn feedi ng on th e bod ies of naturally infected sna ils. A . cnu ton ensis is able to in vad e th e bra in of m an and of th e monkey and to prod uce cere bra l ang iostrongylosis (pa rasitic eosinop h ilic m eningo­ encep halitis) (see Parasites of Man). In addi tion to H awa ii, A . can ton cusis has been rep orted a 1lI0n g ra ts from other islands of th e Pacifi c and part s of Southeas t Asia, as follows (fig. 4): Esp ir itu Sa nto, N ew Hebrides (Alica ta, 1963n); Formosa (Yokoga wa, 1937): Guadalcan al, Solo mo n Islands (Loison, 1964); G uam (Lindq uist and L i, 1955); L ifou , Loyalt y Islands (Alica ta, 1963a); Ma laya (Sch acher and Che­ ong , 1960); few Cal edonia (Alica ta, 19G3n); Mo en, Pingalap, and Pori a p e, Caro line Island s (] ackson, 1962); R ar oton ga, Cook Islands (Alic ata and Mc­ Cart hy, 1964); R ota, Sa ipan, and T'in ian , Mariana Islands (Alica ta , 1961c); T ah it i (Alicata, 1962a); Ch ina (Chen, 1935); and T hailan d (P unyagup ta, 1964). In add ition to rats of the ge nus Rattus, A. can ion ensis h as also been reported from the bandicoot rat, B ari dicot a indica. nemoriuaga, in Formosa (Ku n tz and M yers, 1964).

TA PE WO R~ IS

In a survey cond ucted by Ash (1962b), H v m enolc pis uana (fi g. 3~ b) and H. diminuia (fig. 32c) wer e recovered in approx im ately 50 percent of the rats exa m ined in H onolulu. T he infecti ve stage (strobilocercus) of the ca t tape­ worm, H ydat igera taeniacjormis, was lo und i n th e li ver of about 40 percent of the rats exa m ined (fig. 311). T he high in ciden ce of th is larval par asite in th e rat correspo nded with the frequen cy of occurrence of th e ad u lt pa rasite in th e ca t (see Parasites of Cat). H . nan n also has been fou nd in man in H awaii (see Parasites of Man). Altho ug h most tilpeworms have an indirect lif e cycle, H . n on a ca n have eit he r a direct or an ind irect life cycle . I n the forme r, the eggs are in gested by th e defin itive host and the yo ung larvae penetrate the in testinal wall to form a ta illess cysticercoid. T hese eve nt ua lly eme rge into t he lumen o f th e