Examination of Paramphistomid Species of Bulgarian Domestic Ruminants

Dr. Ottó SEY — Dr. Yurij VISHNYAKOV Department of Zoology, College of Education, Pécs, Hungary — Department of Parasitology, University of Veterinary Science, ,

"Examination of paramphistomid species of Bulgarian domestic ruminants. " - Sey, O. - Vishnyakov, Yu. - Parasit. Hung. 9^ 25-29. 1976.

ABSTRACT. Paramphistomid specimens collected in nineteen localities of Bul­ garia from cattle, sheep and buffalo proved to belong to a single species: Pa- ramphistomum daubneyi Dinnik, 1962. Characters to be taken into account when differentiating P. daubneyi from closely related species are discussed in detail.

Material and Methods

In 1974/75 an extensive collecting was carried out in Bulgaria in order to survey the species of Paramphistomum in domestic ruminants. The test material was collected from cattle in , , Godech, , , Kirnalovo, Kotel, Mihai- lovgrad, , Rousse, , Topola, , Torgovishche, ; from sheep in Kavrikirovo, Kirdzhali, Kremene, Oborishte, Vidin and from buffalo in Sliven.

Flukes after having been removed from the rumen were fixed and stored in 70% alcohol, then median sagittal sections were prepared with the usual histological method. Of every sample five specimens were sectioned and another five were dissected to detect the po­ sition of the ends of caeca and convolutions of the pars musculosa (number of speci­ mens were limited).

Although several authors have examined Paramphistomids of Bulgaria (VISHNYAKOV and IVANOV, 1964; VISHNYAKOV et al. 1971; POPOV et al. 1967; MIHAILOVA et al. 1974; KOTRLA et al. 1974) their conception concerning the established species is by no means uniform.

Result and Discussion

The identification of the present material was based on gross and histomorphology, at the same time specificity to intermediate hosts was also taken into consideration. Sam­ ples of the available Paramphistomid material proved to be a single species: Paramphi­ stomum daubneyi Dinnik, 1962 all but one deriving from cattle in Kavarna, to be dis­ cussed later.

In the Bulgarian literature VISHNYAKOV et al. (1971) were the first to report the oc­ currence of a P. daubneyi - like species from sheep.

P. daubneyi, belonging to the group of species having Microbothrium type of genital at­ rium shows the closest similarity to P. microbothrium Fischoeder, 1901 and P. cla- vula Näsmark, 1937 reported in Bulgaria (MEREMINSKIÍ and VISHNYAKOV, 1969; VISH- NYAKOV et al. 1971; MIHAILOVA et al. 1974). Owing to the similarity of P. daubneyi to these species and because P. microbothrium was repeatedly reported from Bulgaria special attention should be paid to those characters important in the identification of the species in question.

We used the following morphological characters to separate P. daubneyi and P. micro- bothrium:

The terminal parts of the caeca of P. daubneyi turn towards the ventral surface of the body, whereas in P. microbothrium they turn dorsalwards. During our examinations po­ sition of the caeca was carefully studied and in 85 of 95 specimens they showed typical position, i. e. turned ventralwards, in 3 specimens the right and in 7 specimens the left terminal parts exhibited discrepancy from the typical position. In these cases the ter­ minal parts of the caeca turned straigh towards the posterior or somewhat to the dorsal or distinctly the dorsal direction. It should be stressed, however, that the terminal parts of the atypical caeca were situated in the lateral region of the body and they did not penetrate into the dorsal part of it. Having made histological sections of those specimens with atypical caeca we could not find any other correlative deviations as compared to specimens having typical ends of the caeca. Therefore we believe that they are individual variations and the position of the terminal parts of the caeca seems to be a valuable and fairly constant character.

The structure of the muscular organs, pharynx and acetabulum through histological sec­ tions did not display any remarkable deviations from the features described by NAS- MARK (1937) for these organs under the name Paramphistomum types (Figs. 1, 14-16). The genital atrium, however, deserves more attention since it is of specific importance.

It should be remembered that the genital atrium as a muscular organ may exhibit diffe­ rent appearances depending on its physiological state at the moment of fixation. There­ fore it can hardly be expected that each specimen should show the same "typical" form described in NASMARK's (1937) or in other's papers. Microphotographs enclosed intro­ duce a series of genital atria, some of them can be called "typical" (Figs. 3-6) where­ as others (Figs. 7-10) represent the extreme appearance of this type which can easily give way to misunderstanding (e. g. Fig. 7 and Figs. 8, 9 at first view resemble to Both- riophoron and Calicophoron types, respectively). Although the genital atrium of both P. daubneyi and P. microbothrium are of the Microbothrium type, nevertheless, we have found that the sphincter papillae of P. microbothrium is several times stronger than that of P. daubneyi (Figs. 11 and 12).

Apart from the morphological features, the examination of specificity to intermediate hosts can also give us useful help in a correct identification.

It is common knowledge that the spectrum of intermediate hosts of flukes is narrower than that of their final hosts. One aspect of the intimate connection between the mira- cidium and the intermediate host was illustrated by RICHARDS and MERRITT (1972), who experimentally demonstrated that the susceptibility of juvenile Biomphalaria glabra- ta to Schistosoma mansoni infection is regulated by several genetic factors. Although

Figs. 1-11: Median sagittal sections of organs of Paramphistomum daubneyi. 1-2 = pharynx; 3-11 = genital atrium with different appearance. Fig. 12: Genital atrium of a Paramphistomum microbothrium from Egypt. Fig. 13: Genital atrium of Paramphistomum clavula, Näsmark's material; Figs. 11-13 were taken with the same magnification; compare the measure­ ments of genital sphincter and sphincter papillae. Figs. 14-15: Dorsal half of acetabulum of P. daubneyi. Fig. 16: Ventral half of acetabulum of P. daubneyi. (Photo Sey) experiments of alike nature have not yet been done in connection with Paramphistomids we may well suppose that the intermediate host specificity is determined by similar fa­ ctors in case of Paramphistomids, too.

The analysis of the intermediate host spectrum of Paramphistomids suggests that the specificity to such hosts can vary with the species of parasites themselves. E, g, Pa- ramphistomum sukari Dinnik, 1954 develops only in the Planorbid species Biomphalaria pfeifferi (DINNIK and DINNIK, 1957), while the intermediate hosts of P. ichikawai Fu- kui, 1922, occurring in Japan, the USSR, Europe and Australia, are Helicorbis sujfu- nensis as well as Gyraulus filialis in the USSR (KISILEV, 1967), Planorbis planorbis in Hungary (unpubHshed data) and Segnitilia alphena in Australia (DURIE, 1953), all being Planorbid snails. Until now no species of Paramphistomids have been found to develop in intermediate hosts belonging to two or more different families, therefore the speci­ ficity of Paramphistomids to the species of their adequate intermediate hosts seems to be a quite constant feature.

In searching for the intermediate host of P. daubneyi, DINNIK (1962), tried to infect several species of Bulinid, Lymnaeid, Physid and Planorbid snails, but others than Lymnaea truncatula did not pick up the miracidia of P. daubneyi. At the same time he found that infections of L. truncatula with miracidia of P. microbothrium, whose inter­ mediate hosts are Bulinid snails, were unsuccessful. Infestations performed in this la­ boratory (Hungary) with Planorbis planorbis were also unsuccessful in spite of the fact that Planorbid snails are phylogenetically more closely related to Bulinids than to Lymn- aeids. In other words P. daubneyi shows strict specificity to its intermediate host, L. truncatula. It seems fairly certain that the geographical distribution of P. microbothri- um corresponds to that of its Bulinid intermediate hosts (B, tropicus and B, truncatus). As Bulinids are not indigenous in Bulgaria, they occur solely in some South-West Euro­ pean countries (the Spanish Peninsula, Sardinia, Corsuca; HAAS, 1935), the species formerly described in Bulgaria as P. microbothrium {ME RE MINSKlí and VISHNYAKOV, 1969; VASSILEV and SAMNALIEV, 1974; MIHAILOVA et al. 1974) is probably a mis­ judged; P^_daubney_i. As a result of examinations of naturaUy infected snails carried out by KOSAROFF and MIHAILOVA (1959) and POPOV et al. (1967) three species of Lymnaeid snails (L. peregra, L. truncatula, L. turricula) harboured Cercaria pigmentata, a type of Paramphistomid cercariae. Taking the above short analysis of the specificity into consideration KOSAROFF and MIHAILOVA's (1959) and POPOV et al.'s (1967) results are in accordance with our argumentation.

P. clavula Näsmark (1937) is the other species of the Bulgarian fauna (MIHAILOVA et. aï! 1974), which shows similarity to P. daubneyi. It has a Clavula type of genital at­ rium resembling in structure to the Microbothrium type. The genital sphincter of P. clavula, however, is enormously developed and it is about three to four times larger than that of P. daubneyi (Figs. 11-13 were taken with the same magnification, demon- straiting the different sizes of sphincter papillae and genital'sphincter of P. daubneyi, P. microbothrium and P. clavula). The intermediate host of P. clavula is Bulinus abes- synicus (SOBRERO, 1962) and the specificity discussed in connection with P. micro­ bothrium is most likely related to this species as well.

Among the Paramphistomid material from cattle in Kavarna most specimens showed a strongly protruded and therefore smaller genital opening which is worth mentioning, be­ cause such a form occurs scarcely in both P. daubneyi or P. microbothrium. The structure and measurements of other organs, however, fell within the limits given by DINNIK (1962) and SEY (1974) for P. daubneyi. This appearance (Fig. 10) is very prob­ ably allied with a longer prefixative treatment in water, because such protruded génital opening was seen occasionally in specimens of other Bulgarian samples, too (Figs. 8 and 9). This assumption is supported by the fact, that the parenchymal cells were empty and the pharynx was also protruded (Fig. 2) owing to endosmosis. As of this sample only a limited number of specimens were available and prefixation circumstances were unknown, specimens of this type were considered as a variation of P. daubneyi. In Bulgaria about 10 species of rumen flukes have been reported by Bulgarian authors from domestic ruminants, some of them occurring for the first time in Europe (MIHAI­ LOVA et al., 1974). These results however require revision in the light of a broader field of examination than merely the morphological characters.

SEY, O. — VISNYAKOV, J.: Kérődző háziállatok bendőmételyeinek vizsgálata Bulgáriában

Bulgária tizenkilenc helységében szarvasmarhából, juhból és bivalyból gyűjtött Param­ phistomum anyag egyetlen fajnak, Paramphistomum daubneyi Dinnik, 1962 bizonyult. A dolgozat bemutatja a fajmeghatározasnal követett eljárást es részletezi a P. daubneyihez közel álló fajok elkülönítésére alkalmas bélyegeket.

References

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SCZliERO, R. (1962): Ricostruzione del ciclo de vita Paramphistomum clavula (Näs- mark, 1937), parassita dei ruminanti in Somalia. - Parassitologia, 4_. 165-167. VASSILEV, I. - SAMNELIEV, P. (1974): Development of Paramphistomum microboth­ rium in an intermediate host Galba truncatula. - ICOPA III, B 2. 352. VISHNYAKOV, Yu. - IVANOV, V. (1964): Die Paramphistomatose des Rindes I. Ver­ breitung, Klinik und Therapieversuche. - Angew. Parasit., 5. 220-227. VISHNYAKOV, Yu. - MERE MIN SKII, A. I. - KAMBOUROV, P. - GEORGIEV, M. (1971): Razprostranenie na paramfistomatidite pri ovtsete i ustanovyavane vida Paramphis­ tomum' microbothrium Fischoeder, 1901 pri ovtsete i govedata v Sofiyski okr'g. - Nauch. Trud. Vis. Vet. Inst., 22. 463-468.

Received: 11 February, 1976. Dr. Otto SEY Department of Zoology University College H-7624 Pécs, Ifjúság útja 6.

Dr. Yu. VISHNYAKOV University of Veterinary Science Department of Parasitology Sofia 13, Bui. Lenin 73. BULGARIA