Occurrence of Kalicephalus, Strongyloides, and Rhabdias nematodes as most common gastrointestinal parasites in captive snakes of German households and zoological gardens.

Nowadays, snakes established as domestic exotic pets, harboring numerous (zoonotic) gastrointestinal parasites. In this parasitological survey, we used direct saline fecal smears (DSFS) to examine 586 stool samples from 71 different snake species either kept as pets in households or in zoological gardens in Germany. In addition to DSFS, carbol-fuchsin-fecal smears (n = 296), coproantigen ELISA tests (n = 98), and immunofluorescence assays (IFA; n = 77) for the detection reptile Cryptosporidium infections were conducted. Complete dissections of deceased snakes (n = 63) were also performed in order to gain data on endoparasite species burdens affecting domestic snakes. Overall, examined fecal samples contained 20 different parasite taxa: Ancylostomatid Kalicephalus spp. were the most prevalent nematode species (3.3%), followed by Strongyloides/Rhabdias (2.6%), flagellated protozoan trophozoites (e. g., Proteromonadida, Reteromonadida) (2.3%), Monocercomonas spp. (1.9%), Entamoeba spp. (1.4%), unsporulated coccidian oocysts (1.4%), Kapsulotaenia spp. (0.9%), Capillaria spp. (0.7%), indet. trematodes (0.5%), pentastomids (0.5%), spirurids (0.4%), Eimeria spp. (0.4%), ascarids (0.4%), Blastocystis sp. (0.2%), heterakids (0.2%), cestodes (Proteocephalidae) (0.2%), Plagiorchis spp. (0.2%), Cryptosporidium spp. (0.2%), Caryospora epicratesi (0.2%), and Sarcocystis spp. (0.2%). For Cryptosporidium, four carbol-fuchsin-stained smears (1.4%), 12 (12.2%) coproantigen ELISA-examined samples and 5.2% of examined samples were diagnosed with IFA. Fourteen (22.2%) of dissected snakes showed infections with various pathogenic nematode genera and 8 of them (12.7%) died due to protozoan parasitic infections. High prevalences of intestinal protozoan parasites resulting in severe pathological findings observed in dissected snakes call for more detailed investigations on gastrointestinal parasites.

Helminth infracommunity of the cane toad Rhinella marina (Anura: Bufonidae) within its native distribution range.

During August 2010, a total of 66 cane toad Rhinella marina were collected in Laguna de Coyuca, Guerrero, Mexico and examined for the presence of helminths. Ninety-two percent were parasitized by 1 or more parasite species. A total of 4624 individuals were found, belonging to 8 helminth taxa (1 digenean, 1 cestode and 6 nematodes). Infracommunities harbored by this host species are highly variable (mean Jaccard similarity index 0.31±0.27); mean percent similarity index 0.26±0.32) and depauperate (mean richness 1.91±0.92; mean abundance 64.4±100.34); almost 50% of them were dominated by Rhabdias fuelleborni, a skin-penetrating nematode. Differences related to host gender and size were found, since males registered infracommunities with lower species richness and diversity than females. The reproductive condition of females (collected during the breeding season) might explain the results obtained; during this season, females invest less in resistance to infection in favor of investing resources in reproduction. However, confirmation of this statement can only be made by sampling in the dry season, when the toads do not reach their reproductive peak.

New observations - with older ones reviewed - on mass migrations in millipedes based on a recent outbreak on Hachijojima (Izu Islands) of the polydesmid diplopod (Chamberlinius hualienensis, Wang 1956): Nothing appears to make much sense.

Mass aggregations and migrations of millipedes despite numerous attempts to find causes for their occurrences are still an enigma. They have been reported from both southern and northern hemisphere countries, from highlands and lowlands of both tropical and temperate regions and they can involve species belonging to the orders Julida and Spirobolida, Polydesmida and Glomerida. According to the main suggestions put forward in the past, mass occurrences in Diplopoda occur: (1) because of a lack of food and a population increase beyond sustainable levels; (2) for the purpose of reproduction and in order to locate suitable oviposition sites; (3) to find overwintering or aestivation sites; (4) because of habitat disruption and changes in the local environment; (5) as a consequence of weather conditions the year (or winter and spring) before. A recent outbreak (November 2014) of a mass migration of the polydesmid Chamberlinius hualienensis Wang 1956 on the Japanese Izu Island of Hachijojima 300 km to the south of Tokyo gave this author an opportunity to review the existing literature on millipede mass migrations and to carry out additional observations on the phenomenon in the field as well as the laboratory. Hitherto unreported heavy infestations with phoretic deutonymphs of the mite Histiostoma sp. as well as dense populations of internal rhabditid nematodes (Oscheius cf. necromena and an unidentified species of the genus Fictor), suggest that infestations of this kind could be necromenic and either have been a contributing factor for the mass migration or been a consequence of so many individuals occurring together at close proximity. It is concluded that mass migrations and aggregations in millipedes do not have one common cause, but represent phenomena that often are seasonally recurring events and appear identical in their outcome, but which have evolved as responses to different causes in different millipede taxa and therefore need to be examined on a case-to-case basis.

Rhabdias (Nematoda: Rhabdiasidae) from Chamaeleonidae (Sauria): two new species from Trioceros ellioti in East Africa and one from Brookesia superciliaris in Madagascar.

Rhabdias casiraghii n. sp. and R. kibiraensis n. sp. are described from Trioceros ellioti from Burundi and co-infection was observed in one of the host specimens. Distinctive characters between these species are, among others, the mouth and buccal capsule in front view, both of which are round in the former and laterally flattened in the latter species. Both species have a complete set of submedian head papillae (three in each submedian axis) as observed in the fourth stage larva of R. americanus from anurans. This primitive character opposes them to other species parasitic in Chamaeleonidae that have a single papilla per axis. The third species is the first described from the primitive chamaeleonid genus Brookesia; R. brygooi n. sp. from B. superciliaris from Madagascar can be distinguished from other Rhabdias in Chamaeleonidae by the small diameter of its mouth and buccal capsule. In this character, it resembles parasites from anurans. However, its infective larva has a rounded caudal extremity ornated with buds, as described in species of Rhabdias parasitic in Chamaeleonidae.

Heterozygosity and parasite intensity: lung parasites in the water frog hybridization complex.

In hybridogenetic systems, hybrid individuals are fully heterozygous because one of the parental genomes is discarded from the germinal line before meiosis. Such systems offer the opportunity to investigate the influence of heterozygosity on susceptibility to parasites. We studied the intensity of lung parasites (the roundworm Rhabdias bufomis and the fluke Haplometra cylindracea) in 3 populations of water frogs of the Rana lessonae-esculenta complex in eastern France. In these mixed populations, hybrid frogs (R. esculenta) outnumbered parental ones (R. lessonae). Despite variation in parasite intensity and demographic variability among populations, the relationship between host age and intensity of parasitism suggests a higher susceptibility in parentals than in hybrids. Mortality is probably enhanced by lung parasites in parental frogs. On the other hand, while parental frogs harboured higher numbers of H. cylindracea than hybrid frogs, the latter had higher numbers of R. bufonis. Despite such discrepancies, these results support the hybrid resistance hypothesis, although other factors, such as differences in body size, age-related immunity, differential exposure risks and hemiclonal selection, could also contribute to the observed patterns of infection.

First report of Rhabdias (Nematoda: Rhabdiasoidea) from lungs of montane chameleons in Cameroon: description of two new species and notes on biology.

The lung nematodes of the genus Rhabdias parasitic in chameleons were previously only known from east Africa and Madagascar. Two new species are described from Cameroon: i) Rhabdias okuensis n. sp., type-host Chamaeleo (Trioceros) quadricomis gracilior, from Mont Oku, is frequent; it resembles R. jarki from Burundi, with a short buccal capsule and a long, thin oesophagus, and is distinguished by its large cervical vesicle and cephalic characters (mouth aperture, papillae). The female parasites are hermaphroditic (spermatozoa identified) and they pierce the lung wall and induce lesions, as R. jarki. In the same locality, another chameleon, C. (T.) w. wiedersheimi also harbours R. okuensis, as demonstrated with the 12S rDNA and coxl gene sequences. ii) R. cristati n. sp., type-host C. (T.) cristatus, from Mount Cameroon, is described from one heavily infected specimen; it resembles R. chamaeleonis from East Africa, and is distinguished by the large buccal capsule and the thick apex of the intestine. The free-living phase, studied in R. okuensis, presents characters of other Rhabdias from chameleons: heterogony, development of larvae through matricidal endotoky, infective larval stages with a thick, rounded caudal extremity, exuvium transformed into a thick cuticular sheeth. Each free-living female produces one larva, as in other African Rhabdias, whereas the female of R. gemellipara, a parasite of a Malagasy chameleon, produces two larvae.

Rhabdias anolis n. sp. (Nematoda: Rhabdiasidae) from the lizard, Anolis frenatus (Sauria: Polychrotidae), from Panama.

Rhabdias anolis n. sp. from the lungs of Anolis frenatus collected in Panama is described and illustrated. Rhabdias anolis n. sp. represents the 45th species assigned to the genus and the ninth from the Notropical Realm. It is distinguished from all other Neotropical species by the presence of a pair of sessile lateral papillae on its tail.