F. R. Matuschka

Cannibalism and autotomy as predator-prey relationship for monoxenous Sarcosporidia

In search for the final host of Sarcocystis gallotiae, sarcocysts of naturally infected Canarian lizards, Gallotia galloti, were fed to vertebrate predators of the lizard. Repeated transmission experiments remained negative. Routine check of the feces of the wild G. galloti revealed shedding of sporocysts. The sporocysts were administered to small vertebrates, which may function as prey for G. galloti. The transmission experiments remained negative. The observation of a high intraspecific aggression of G. galloti, including cannibalism and autotomy, seemed to support the hypothesis that this behavior might be the base of a an unexpected predator-prey relationship. Sarcocysts of S. gallotiae, fed to two laboratory-bred G. galloti resulted in excretion of sporulated sporocysts measuring 9.7 (9.2–12.2)×7.7 (6.6–9.2) Μm. Oral inoculation of two laboratory-bred G. galloti with experimentally gained sporocysts, led to the development of sarcocysts of 150–200 Μm in length and 80–110 Μm in width in the musculature of the lizards 153 days p.i. The sarcocysts were identified as S. gallotiae by light and electron microscopy. In epithelial cells of the intestine of G. galloti, which had experimentally been infected with sarcocysts of S. gallotiae, stages of gamogony and sporogony were found. We suggest that the life cycle of S. gallotiae is monoxenous and not obligatorily heteroxenous. The genus Sarcocystis seems to be more flexible in its biologic adaptability to utilize autotomy and cannibalism for completing its cycle than had heretofore been assumed.

Reptiles as intermediate and/or final hosts of Sarcosporidia.

A revision of the parasitic protozoan genus Sarcocystis which has reptiles as intermediate and/or final hosts is given.Twelve species described as having reptiles as intermediate hosts are considered valid species of the genus Sarcocystis. Snakes have been shown experimentally to be the final hosts of ten other Sarcocystis species which have rodents as their intermediate hosts. One species, S. podarcicolubris, has poikilothermic intermediate and final hosts.Classification of a new Sarcocystis species based either on scantily described cysts or only on sporulated oocysts or sporocysts from feces is not sufficient and cannot be justified. A new species should be recognised only after experimental retransmission and/or because of unequivocal morphological characteristics of the sarcocyst.

Nocturnal detachment of the tick Ixodes hexagonus from nocturnally active hosts

Abstract. To determine whether the pattern of engorgement of Ixodes hexagonus Leach (Acarina: Ixodidae) in Central Europe may influence host specificity, the host relationships of the sub‐adult stages of this tick were examined and the time of detachment compared with the activity patterns of various candidate vertebrate hosts.

Life cycle studies onSarcocystis dirumpens sp.n. with regard to host specificity

Four differentBitis species (B. arietans, B. caudalis, B. gabonica, B. nasicornis) were shown to function as definitive hosts forSarcocystis dirumpens, isolated from a naturally infectedB. nasicornis. The experimentally infected snakes excreted sporocysts measuring 11.1 (10.6–11.6)×8.1 (7.9–8.3) μm. By repeated retransmission studies several rodents from the generaMesocricetus, Phodopus, Gerbillus, Meriones, Mastomys andMus were proved to be experimental intermediate hosts. After inoculation of these rodents with sporocysts excreted by the experimentally infectedBitis species sarcocysts with a length of up to 2.5 cm and a width of circa 100–400 μm developed in the rodents, depending on the duration of the infection. Under light microscopic observation the cyst wall appeared smooth. The bradyzoites measured about 8–9×2 μm.

Cyclic transmission of an AfricanBesnoitia species by snakes of the genusBitis to several rodents

By repeated retransmission studies four differentBitis species (B. arietans, B. caudalis, B. gabonica, B. nasicornis), whose geographic distribution covers almost all of Africa, were proved to be the final hosts forBesnoitia species. The experimentally infected snakes shed sporocysts measuring 12.0 (11.7–13.1)×8.8 (7.8–9.6) μm. In these experiments, several rodents from the generaMesocricetus, Phodopus, Gerbillus, Meriones, Mastomys andMus turned out to be the intermediate hosts. The inoculation of these mammals with sporocysts excreted byBitis species resulted in macroscopically visibleBesnoitia cysts measuring up to 2.5 mm in the connective tissue of the mammals. These findings may lead us to a new way of thinking as regards research on besnoitiosis in cattle, since it has to be taken into consideration that small mammals may function as reservoir hosts.

Differentiating betweenBesnoitia besnoiti from cattle andSarcocystis hoarensis from rodents

To provide a biological basis for studies designed to establish the mode of transmission of the veterinary pathogenBesnoitia besnoiti, we compared salient features of this pathogen in cattle with those ofSarcocystis hoarensis in rodents. The cysts and cystozoites of these organisms can readily be distinguished morphologically. In contrast toS. hoarensis which is well adapted to rodents,B. besnoiti fails to mature in jirds or mice and generally is lethal in jirds. Serological reagents discriminately detect these pathogens.B. besnoiti, therefore, can unambiguously be differentiated fromS. hoarensis either by morphological or serological methods or on the basis of experimental comparisons of virulence in laboratory rodents.

Isospora colubris n. sp. from the Western whip snake,Coluber viridiflavus, (Serpentes: Colubridae)

According to Pell6rdy (1974, Coccidia and Coccidiosis. 2nd ed Verlag Paul Parey, Berlin) sixteen species of the coccidian genus Isospora parasitizing ophidian hosts had been described up to 1972. The finding of only one other species in addition to those listed by Pell6rdy has been reported by Lainson and Shaw (1973, J Protozool 20:358-362). In the present study oocysts of an isosporoid coccidium found in the feces of a Western whip snake, Coluber viridiflavus, from Italy are described and considered to be a distinct new Isospora species. The oocysts originated from the feces of a semiadult male Western whip snake, Coluber viridiflavus. The snake was captured alive in Italy by a private collector, who allowed it to be kept in the laboratory for several months. During that time the snake was fed on baby laboratory mice only. Fecal samples were screened routinely for parasites using ZnC12-NaC1 flotation. For sporulation oocysts were harvested from feces and treated as reported previously by Matuschka (1984, Can J Zool 62: 1525-1527). The naturally infected Western whip snake, Coluber viridiflavus, excreted unsporulated or partly sporulated isosporoid oocysts. Sporulation of the oocysts was usually completed within 24 h at 21 _+2 ~ C. Very few oocysts were passed by the snake with each defecation. The oocysts shed by this snake are described here as those of a new species.

Caryospora telescopis sp. n. (Apicomplexa: Eimeriidae) from the Cat snake, Telescopus fallax (Serpentes: Colubridae), and Caryospora spec. from the West Caucasian viper, Vipera kaznakovi (Serpentes: Viperidae)

Summary Oocysts of a new coccidian parasite, Caryospora telescopis , sp. n. (Apicomplexa: Eimeriidae) are described from the feces of a Cat snake, Telescopus fallax , from Greece, and their morphology is compared to that of similar Caryospora species reported from ophidian hosts. The spherical oocysts of Caryospora telescopis measure 21.5 (19.1–23.5) μm and do not possess micropyle and oocyst residuum. Sporocysts are ovoid, 11.4 (10.3–11.8) μm in width by 15 (14.7–16.2) μm in length, with prominent reel shaped Stieda body as well as substieda body. Sporocyst residuum present and consisting of numerous granules. The sporulation was completed in 48 to 72 h at 23 ± 2 °C. This is the first account of the genus Caryospora from the Cat snake, Telescopus fallax . In addition the finding of Caryospora oocysts excreted by the West Caucasian viper, Vipera kaznakovi , is reported and discussed.

Caryospora najadae sp.n. (Apicomplexa: Eimeriidae) from Dahl's whip snake,Coluber najadum (Serpentes: Colubridae)

Oocysts of a newCaryospora species,Caryospora najadae, are described from the feces of a Dahls whip snake,Coluber najadum, from Israel. The spherical oocysts ofC. najadae measure 31.9(27.9–36.3) μm in diameter and lack a micropyle and a oocyst residuum. The oocyst wall is between 1.5–2 μm thick. The ovoid sporocysts are 15.2(14.0–16.4) μm wide and 21.1(19.9–22.2) μm long. A sporocyst residuum, a Stieda body and substieda body are present. The sporulation is completed in about 72 h at 21.1±2° C. Sporozoites are elongate measuring circa 19–21×2–2.5 μm.

Cuticular permeability to Dextran of the endoparasiteStylops (Insecta, Strepsiptera)

SummaryThe endoparasitic insectStylops sp. (Insecta, Strepsiptera) absorbs materials only through its body cuticle from the haemolymph of its host,Andrena fulva Schrk. (Insecta, Hymenoptera). The passage of a polysaccharide, Dextran-3, through the chitinous cuticle of the parasite was observed by means of its fluorescence and by electron microscopy; after 15 min exposure, Dextran was found to be present between the chitin layers, on the surface of epidermal, muscle and egg cells, and in the haemolymph of the parasite.