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&@lJ&PROTOZOOLOGICA

Acta Protozoologica (1995) 34: 233 - 235

Shortcommunication

lsospora sp. (Apicomplexa: Eimeriidae) in Icterine Warbler (Hippolaisicterina, Passeriformes: Sylviidae): the Possibility of Parents toNestlings Transmission

Milena SVOBODOVÁ1 and Magda CmULKOV Á2

lDepartment of Parasitology and 2Department of Zoology, Faculty of Science, Charles University, Prague, CzechRepublic

Summary. The prevalence of lsospora sr. in a population of icterine warbler was studied to ascertain the possibility of transmission ofoocysts from parents to nestlings. Seventy-two adults and nestlings in 51 nests were examined; lsospora sr. oocysts were found in 91.2%of samples from females, 78.9% from males and 35.3% from nestlings. There was no significant difference between the prevalence ofinfection in females and males; the difference between adults and nestlings was statistically highly significant. The prevalence in nestlingsdepended on their age (24% in 7-9 days and 50% in 10-12 days old nestlings). From 39 nests with I or both parents harboring oocysts,12 nests contained infected youngs and 27 were infection free; the difference between the average age of nestlings in the infected anduninfected group (9.7 and 9.2 days, respectively) was not significant. As no nests with infection-free parents were found, we could notconc1udeif nestlings were infected by food contaminated accidentally or directly from their positive parents.

Key words. lsospora, Hippolais icterina, icterine warbler, coccidia, transmission, prevalence.

Coccidia of the genus /sospora are commonparasites of passerine birds; their prevalence in somepopulations can reach 40% (Scholtyseck and Przygod-da 1956, Svobodová 1994). These prevalences areinteresting because /sospora spr. of passerine birds aremonoxenous, oocysts are excreted in feces and thepossibility of infection acquired with food seems to below due to the dispersion of oocysts in the environ-ment. A possible manner of infection is the direct

Address for correspondence: M. Svobodová, Department ofParasitology, Faculty of Science, Charles University, Vinicná 7,12844 Prague 2, Czech Republic; Fax: ++ 42 2 299713;E-mail: kulda@csearn.bitnet

transmission between individuals, e. g., during thenesting period when oocysts could be transmitted tonestlings with food contarninated by feces of infectedparents. Przygodda and Scholtyseck (1961) found lhalthe prevalence of infection with /sospora spr. is higherin older nestlings of passerine birds; however, they didnot examine parent birds.

In 1989-1991, the breeding biology of a populationof icterine warbler (Hippolais icterina, Passeriformes:Sylviidae) in Central Bohemia, Czech Republic, wasstudied. Warblers are mainly insectivorous and bothfemales and males feed the young (Hudec 1983,Payevsky 1987). Our attention was directed to

234 M. Svobodová and M. Cibulková

monoxenous coccidia to ascertain if there is some

relation between the oocyst shedding in parents andnestlings.

Warblers were caught in nets using 2 methods: maleswere attracted by tape replayed song, both sexes werecaught near nests with nestlings (Cibulková 1993). Birdswere kept in tissue bags (max. 1 h), released, and thefeces were collected. Samples from nestlings were col-lected during controls of nests, feces from siblings beingmixed together and representing ODesample. Accuratehatching date was detected during previous nesl con-trols. Samples of feces were kept in 2% aqueous potas-sium bichromate (K2Cr207) solution for three days atroom temperature to allow oocysts sporulation and thenstored at 4°C. First microscopical examination ofsamples was direct; when no oocysts were found furtherexamination involved flotation of the material in 33%

aqueous zinc sulfate (ZnSO4.7H2O) solution.A total of 72 adult birds and nestlings in 51 nests were

examined; 91.2% of samples from females (n=34),78.9% from ma1es (n=38) and 35.3% from nestlings .(n=5l) being positive to oocysts of the genus lsospora(see Table 1.) Oocysts were subsphaerical, measuring26.8 x 24.8 !lm (19.5-33.8 x 18.0-31.5, n=279; fordetailed description see Svobodová 1994). There was nosignificant difference between the prevalence of infec-tion in adult females and males (G-test, G = 2.15,p>0.05). The preva1encein adults (84.7%) was 2.4 timeshigher lhali in nestlings; the difference is highly sig-nificant (G-test,G = 32.63,p<O.Ol).Age dependence ofoocyst shedding was proved by division of nestling in 2age groups, older nestlingsbeing positive more frequent-ly (see Table 2); the difference is significant for one-tailed hypothesis (G-test, G =3.67, p<O.l). In 39 nests,ODeor both parents were also examined. All nestlingsfrom these nests had at least ODeparent positive tolsospora oocysts; 12 of the nests contained infectedyoungs, 27 did not. No family was found with allmembers being negative, nor a positive nesl with nega-

Table 1

n - number of examined, + - number of infected, % - prevalence

Table 2

Preva1ence of lsospora sp. oocysts in two age groups of nestlings

tive parents. Average age of infected and uninfectednestlings was 9.7 and 9.2 days, respectively; however,the difference was not significant (Mann- WhitneyU-test, Z = -1.25, p=0.21).

Coccidia of the genus lsospora are very common inthis population of icterine warbler, inc1udingnestlings.There are probab1y\more mechanisms for the main-

tenance of lsospora~n the population of the host.Generally, lsospora spI". of birds are transmitted viaoocyst-contaminated food or water; however, the directtransmission should be considered. The fact that oocystsare not infective before sporulation could decrease thepossibility of such transmission; but the process dependson temperature and lasts auly 24 h for some passerinespecies of lsospora (Stabler and Kitzmiller 1972, Barréand Troncy 1974). Oocysts adhered to the plumage andother parts of the body of parents could be a source ofinfection for their youngs. The existence of families withinfected parents and negative nestlings may be explainedin two ways: (1) the youngs are not (yet) infected; (2)the youngs are infected bul not Jet shedding oocysts dueto the prepatent period, which lasts at least 4-5 days(Stabler and Kitzmiller 1972, Box 1977, Cawthorn andWobeser 1985, Amoudi 1990).

As no nests with lsospora-free parents were found,we cannot determine whether nestlings were infected viafood contaminated by their parents or accidentally (byoocysts dispersed in the environment).

REFERENCES

Amoudi M.A. (1990) The life cyc1e of lsospora elmahalensis in thewhite-cheeked bulbul (Pycnonotus leucogenys). Bull. lnst. Zo-ol.,Acad. Sinica 29: 265-272

Barré N., Troncy P. M. (1974) Note sur line coccidie rencontrée chezquelques Ploceidae du Tchad: lsospora xerophila n. sp. Z. Para-sitenk. 44: 139-147

Box E. D. (1977) Life cyc1e of two Isospora species in the canary,Serinus canarius Linnaeus. J. Protozool. 24: 57-67

Cawthorn R. J., Wobeser G. A. (1985) Exogenous and endogenousstages of lsospora brachyrhynchi sp. n. (Protozoa: Eimeriidae)from the American crow Corvus brachyrhynchos Brehm. Can. J.Zoo I. 63: 2639-2645

Cibulková M. (1993) Me;hods of catching icterine warblers (Hippo-lais icterina). Zpr. Ceské spol. omitol., Prague, 36: 3-11 (inCzech)

Preva!ence of lsospora sp. oocysts in icterine warb1er

Year Females Males Nestlings

n + % n + % n + %

1989 11 9 81.8 8 7 87.5 16 6 37.51990 16 16 100 20 13 65.0 23 7 30.41991 7 6 85.7 10 10100 12 5 41.7

Total 34 31 91.2 38 30 78.9 51 18 35.3

Age (days) Number of Number of Preva1enceexamined infected (%)

7-9 29 7 24.110-12 22 11 50.0

Hudec K. (Ed.) (1983). The fauna of CSSR. Birds nUl. Prague (inCzech)

Paye'vsky V. A. (1987) Breeding biology and demography of theicterine warbler (Hippolais icterina). Ornitologija, Moscow, 22:22-30 (in Russian)

Przygodda W., Scholtyseck E. (1961) Die Coccidieninfection beiNestlingen. Beitr. Vogelk. 7: 224-229

Scholtyseck E., Przygodda W. (1956) Die Coccidiose der V6gel.Vogelwelt77: 161-175

lsospora sp. infection in nestlings 235

Stabler R. M., Kitzmiller N. J. (1972) lsospora petrochelidon sr. n.(Protozoa: Eimeriidae) from the cliff swallow, Petrochelidonpyrrhonota. J. Protozool. 19: 248-251

Svobodová M. (1994) lsospora, Caryospora and Eimeria (Apicom-plexa: Eimeriidae) of passeriform birds from Czech Republic.Acta Protozool. 33: 101-108

Received on 23th March, 1995; accepted 5th Apnl, 1995