Diversity of helminths in polish reptiles: a review

Parasites of reptiles in Iran (1922-2023): A literature review

Reptiles are among the most diverse groups of animals, inhabiting nearly all continents and environments. Understanding their parasite biodiversity has garnered significant interest, particularly from a One Health perspective. Although the highly diverse reptile fauna of Iran, comprising 272 species i.e. 89 snakes (Serpentes), 171 lizards (Sauria), 8 turtles, 2 tortoises (Testudines), 1 crocodile (Crocodilia), and 1 worm-lizard (Amphisbaenia), there is a shortage of information about parasites. The present review is a compilation of 62 studies published from 1922 to August 2024. We present information on 56 species of reptiles from five groups (amphisbaenians, crocodiles, testudines, snakes, and lizards) and 98 parasitic taxa belonging to different protozoa and metazoa i.e. nematodes, cestodes, trematodes, acanthocephala, leeches, ticks, mites, and myiasis -producing flies. Although 63 taxa were diagnosed at the species level, 35 parasite taxa were only reported at the genus or family levels. Reviewing the literature, we found a paucity of information about endemic reptiles several of which are vulnerable species. Considering that some of the detected parasites e.g. Cryptosporidium and amoebae have serious clinical and/or public health threats molecular diagnostic techniques are needed for precise identification and understanding of the epidemiology and the potential zoonotic implications associated with parasites of reptiles. There is also a need to understand the exact distribution and host-parasite associations in different reptilian species present in Iran including the role of the reptiles as intermediate and reservoir hosts.

First helminthological data on the Iberian adder, Vipera seoanei

The helminth fauna present in the gut contents of Iberian adders, Vipera seoanei (Squamata: Viperidae), were characterised and analysed in respect to biological and eco-geographic factors that may affect the occurrence and diversity of helminths in this species. A total of 317 samples of preserved stomachs and intestines, covering the distributional range of V. seoanei, were examined. Similar to other Vipera species from the Iberian Peninsula, the helminth fauna was also impoverished in V. seoanei, but unlike other Vipera species from Central and East Europe, helminths were mostly found in adult vipers, and occurred in vipers located at the periphery of the species range, characterised by low elevation, high temperature and precipitation levels, and abundant pastures.

Frequent infection of urban grass snakes (Natrix natrix) oral cavity with Leptophallus nigrovenosus trematode

Land disturbances caused by urban development modify and create novel habitats with novel ecological pressures, which in turn may negatively affect remaining wildlife populations, e.g. by altering interspecific interactions. However, it is not clear whether these modified interactions, e.g. parasitism, affect urban wildlife negatively. This is especially true for reptiles, as even parasitism under natural conditions is understudied in this group. We have observed that up to 35% of grass snakes (Natrix natrix) are infected with the trematode Leptophallus nigrovenosus in urban areas of Kraków, while none of snakes sampled in nearby suburban and non-urban forests exhibited this infection. As this trematode typically inhabits the intestine, we suggest that its occurrence in the oral cavity may be a sign of very high infection rates. However, we did not detect any negative effects of observed infection on body size, mass and body condition of affected individuals. On the other hand, competition with other parasite species in suburban and non-urban habitats may be responsible for not detecting L. nigrovenosus in grass snakes from these sites. Nevertheless, interpretation of our findings is difficult, as knowledge on L. nigrovenosus biology is very limited. Our study underlines the necessity to fill the research gap in reptile parasitology.

Parasitic helminths in snakes from the global legal trade

In recent years, the demand for snakes imported from different countries around the world has increased in Slovakia. However, such snakes can be infected with a wide variety of parasites. We have been focused on monitoring the prevalence of parasitic helminths of snakes imported to Slovakia. From 2015 to 2020, 205 samples were collected. We examined faecal samples of 185 live snakes, and a parasitological autopsy was performed on 20 carcasses. Out of a total of 205 snakes, parasitic helminths were found in 44 individuals (21.46 %). Coprological examination of live snakes confirmed positivity for the presence of helminths in 38 snakes (20.54 %). Through parasitological autopsy of all the dead snakes, we found helminths or their eggs in 6 carcasses (30.00 %). The genera of helminths found in the positive snakes were: Ophiotaenia spp., Kapsulotaenia spp., Strongyloides spp., Rhabdias spp., Ophidascaris spp., Ascaridia spp., f. Heterakidae, Kalicephalus spp., Capillaria spp., order Oxyurida and stages of the plerocercoid of an unidentifi ed species of tapeworm in the subcutaneous tissue.

Necropsies disclose a low helminth parasite diversity in periurban howler monkeys

Primate-parasite interactions are often investigated via coprological studies given ethical and conservation restrictions of collecting primate hosts. Yet, these studies are inadequate to recover adult helminths for taxonomic identification and to accurately assess their prevalence, intensity, abundance, and site of infection. Fresh carcasses found in anthropogenic landscapes come as informative and reliable alternatives. In this study, we identified the helminths of brown howler monkeys (Alouatta guariba clamitans) and their sites of infection, and measured their prevalence, intensity, and abundance of infection. We necropsied 18 adult males, 11 adult females, and 7 juvenile males that died in conflicts with the anthropogenic environment (domestic dog attacks, n = 11; electrocutions and road-kills, n = 10 each; unknown, n = 5) in periurban landscapes of southern Brazil between 2013 and 2019. We found three nematodes (Trypanoxyuris minutus, Dipetalonema gracile, and Parabronema bonnei) and one cestode (Bertiella cf. studeri), a diversity estimated to account for a sampling completeness of 99%. Prevalence ranged from 3% for P. bonnei to 100% for T. minutus. Mean abundance ranged from 2 (D. gracile and B. cf. studeri) to 55,116 (T. minutus) and mean intensity of infection ranged from 4 (B. cf. studeri) to 55,116 (T. minutus). Trypanoxyuris minutus sex ratio was strongly male-biased. The intensity of infection with T. minutus was higher in juvenile males and adult females than in adult males. The low parasite diversity and the helminths' mode of transmission are compatible with howlers' arboreality and folivorous-frugivorous diet. The howlers were not infected with soil-transmitted helminth parasites of humans and domestic animals on the ground and probably did not eat invertebrates to complement the diet. Given the lack of evidence of howler health problems, we suggest that the causes of death of the necropsied howlers are the major threats to the long-term conservation of the species at the study periurban landscapes.