Number Of Parasite Species Research Articles

Archaeoparasitology and pathoecology of Buchta Nakhodka, a medieval settlement in the far north of Western Siberia, dating from the 13th century

Buchta Nakhodka, which was inhabited by the Northern Samoyeds, is one of the few sites in the far north of Western Siberia that has been explored archaeologically and archaeoparasitologically. Many factors complicate research work in this region; therefore, any additional study of known sites can provide valuable data. Here, we report the results of soil samples from the cultural layer taken during the excavation of structures of the medieval settlement of Buchta Nakhodka. Six types of human and animal parasite eggs were found in the studied samples. The extent of contamination and number of parasite species varied, depending on the sampling location. The analysis of research results in the historical and archaeological context enabled the reconstruction of certain nutritional habits of the population of Buchta Nakhodka in the 13th century and such activities as hunting, fishing, and dog breeding, as well as an evaluation of the level of hygiene and possible population movements and trade links with neighbouring settlements.

Parasitism with Protozoa and Monogeneans in Fish from the Natural Waters of Romania.

Parasitism by protozoa and monogenean flatworms in freshwater fish from Romania was studied by collecting and examining samples from two major river systems there: 183 fish from 17 species from the Olt River and its tributaries; and 155 fish from 16 species from the Mureș River and its tributary, Târnava Mare. The average rates of parasitism in the samples from the two rivers and their tributaries were as follows: Ichthyiophthirius multifiliis (2%), Trichodina spp. (21%), Apiosoma spp. (18%), Mixobolus spp. (8%), Dactylogyrus spp. (9%), and Gyrodactylus spp. (10%). The number of parasite species varied from one river to another. I. multifiliis was found in only 3 fish species, Trichodina spp. in 13 species, Glosatella spp. in 6 species, and Mixobollus spp., Dactylogyrus spp., and Gyrodactylus spp. in 7 different species each. The highest number of parasite species (six) were identified in the European chub (Squalius cephalus) and schneider (Alburnoides bipunctatus), which seem more susceptible to parasitic infections. The aquatic environment of these rivers may represent a source of parasites for fish from neighboring countries through which these rivers pass.

Checklist of Syngnathidae Parasites in the Black Sea and the Sea of Azov

For the first time data on parasite diversity of Syngnathidae fishes inhabiting the Black and the Sea of Azov, the rivers flowing into these seas and their estuaries accumulated in more than 30 articles and books during almost one century of investigations were summarized. A high level of parasitic organisms’ richness is registered to date: 64 species from 45 genera, 35 families, 14 classes, 10 phyla have been recorded here from 8 species of Syngnathidae fish hosts: Syngnathus abaster Risso, 1827, S. acus L., 1758, S. schmidti Popov, 1927, S. tenuirostis Rathke, 1837, S. typhle L., 1758, S. variegatus Pallas, 1814, Nerophis ophidion (L., 1758), Hippocampus hippocampus (L., 1758). Host-parasite and parasite-host lists are provided, the results for Kinetoplastida, Sporozoa, Microsporidia, Myxozoa, Ciliophora, Platyhelminthes (Monogenea, Trematoda, Cestoda), Nematoda, Acanthocephala, Annelida, and parasitic Arthropoda are presented. Platyhelminthes and Ciliophora (19 and 18 species, respectively) turned out to be the most species-rich taxa of Syngnathidae parasites, while Trematoda was the richest (15 species) class among flatworms. The largest number of parasite species is known from three fish hosts: S. abaster parasite fauna comprises 54 species of 10 phyla (84% of total parasite fauna of this fish family in the region), S. typhle – 27 parasite species belonging to 6 phyla (38%) and relatively pure parasites fauna in H. guttulatus, 14 species of 6 phyla (22%).

A Parasitological Examination on Aquarium Fish Sold in Petshops in Kırıkkale.

The aim of the present study was to determine the prevalence of parasitic infections in aquarium fish sold in local pet shops. Totally 502 fish samples from 8 species were obtained from 7 pet shops. Native preparations were prepared from the gills, fins, skin, intestines, and internal organs of fish and examined under a light microscope. It was detected at the end of the study that 62.7% of the fishes examined were infected with one or more parasite species. Among the fish examined, 28.9% were infected with a single parasite, whereas 33.9% were infected with mixed parasites. Chilodonella sp. identified as the most common species. Other species detected included Trichodina sp., Piscinoodinium sp., Ichthyobodo sp., Ichthyophthirius multifiliis, Apiosoma sp., Epistylis sp., Vorticella sp., Gyrodactylus sp., Dactylogyrus sp., Capillaria sp., Camallanus sp., metacercariae, and nematode larvae, Argulus sp., Philodina sp., Euchlanis sp., Aelosoma sp., and Tetrahymena. The importance of the present study is that highest number of parasite species were detected in aquarium fish sold in pet shops in Türkiye. The aquarium owners should pay attention to the cleanliness of the aquarium water in order to reduce the rate of parasitic infection in fish; when new fish are purchased, they should be taken from reliable sources, and the quarantine process should be observed.

A regional scale study of parasites in Percichthys trucha, an endemic fish of southern South America: insights on diversity and distribution from two decades of field surveys.

The current conservation status of Percichthys trucha (Creole perch) is Least Concern, although the population trend is considered to be decreasing. We conducted an extensive survey of parasite fauna in this species over two decades in its distribution range in Argentina. Fish were collected using gill and trawl nets. Parasites were collected, identified, and counted to calculate prevalence and mean intensity. The present work reports the parasite species infecting P. trucha, using data from our own survey and from previously published records. This information enables us to evaluate infection and distribution patterns, assess the role of P. trucha as host, determine the specificity of the parasites, and evaluate the threat represented by introduced, invasive parasites. The data set consists of a total of 453 host-parasite-locality records, of which only 15 are exclusively bibliographic. We found 44 parasite taxa: 19 digeneans, 4 monogeneans, 5 cestodes, 8 nematodes, 4 acanthocephalans, 3 crustaceans, and 1 mollusk. The most represented families were Diplostomidae, Heterophyidae, and Dactylogyridae. This study increases the number of parasite species known from 25 to 44. It can be concluded that this parasite fauna is characterized by high diversity, particularly of digeneans, and most of the parasites reproduce within this host, a pattern which is related to the top position of this fish species in the trophic webs. Six parasite species (Allocreadium patagonicum, Homalometron papilliferum, Acanthostomoides apophalliformis, Duplaccessorius andinus, Pseudodelphys limnicola, and Hysterothylacium patagonense) exhibit high host specificity (only matures in Creole perches) and are widely distributed, which could now be considered as "biogeographical core helminth fauna." Some P. trucha populations are affected by the invasion of alien fishes like Cyprinus carpio and pathogenic parasites like Lernaea cyprinacea and Schizocotyle acheilognathi. Our findings emphasize the need for further research.

Fasciola hepatica juveniles interact with the host fibrinolytic system as a potential early-stage invasion mechanism.

The trematode Fasciola hepatica is the most widespread causative agent of fasciolosis, a parasitic disease that mainly affects humans and ruminants worldwide. During F. hepatica infection, newly excysted juveniles (FhNEJ) emerge in the duodenum of the mammalian host and migrate towards their definitive location, the intra-hepatic biliary ducts. Understanding how F. hepatica traverses the intestinal wall and migrates towards the liver is pivotal for the development of more successful strategies against fasciolosis. The central enzyme of the mammalian fibrinolytic system is plasmin, a serine protease whose functions are exploited by a number of parasite species owing to its broad spectrum of substrates, including components of tissue extracellular matrices. The aim of the present work is to understand whether FhNEJ co-opt the functions of their host fibrinolytic system as a mechanism to facilitate trans-intestinal migration. A tegument-enriched antigenic extract of FhNEJ (FhNEJ-Teg) was obtained in vitro, and its capability to bind the zymogen plasminogen (PLG) and enhance its conversion to the active protease, plasmin, were analyzed by a combination of enzyme-linked immunosorbent, chromogenic and immunofluorescence assays. Additionally, PLG-binding proteins in FhNEJ-Teg were identified by bidimensional electrophoresis coupled to mass spectrometry analysis, and the interactions were validated using FhNEJ recombinant proteins. Our results show that FhNEJ-Teg contains proteins that bind PLG and stimulate its activation to plasmin, which could facilitate the traversal of the intestinal wall by FhNEJ and contribute to the successful establishment of the parasite within its mammalian host. Altogether, our findings contribute to a better understanding of host-parasite relationships during early fasciolosis and may be exploited from a pharmacological and/or immunological perspective for the development of treatment and control strategies against this global disease.

Helminth Communities of Common Fish Species in the Coastal Zone off Crimea: Species Composition, Diversity, and Structure.

In this paper, we analyzed the diversity and structure of helminth communities of 12 common fish species from the coastal zone of Crimea. A total of 53 helminth species were found. The total number of parasite species per host fish ranged from 3 to 18. Species richness at the infracommunity and component community levels were from 1.4-4.2 to 1.7-7, respectively. The Brillouin index for the infracommunites was 0.1-1, while the Shannon index for the component communities was 0.3-1.2. Component communities demonstrated a bi- or tri-modal distribution of the parasite prevalence and positive correlations between the prevalence and log-transformed abundance indices, thus following the "core-satellite" conception. Overall, the prevalence and abundance index of the dominant parasite in the component communities ranged from 18 to 80% and from 0.6 to 61.5 ind. per fish, respectively. The structure of the helminth component communities demonstrated good accordance with the nestedness mode where the rarest species occurred in the most diverse infracommunities, while the poorest infracommunities were composed of a few dominating species. More than two-thirds of the studied helminth species had an aggregated distribution indicating well-structured and developed communities. Our data provide a basis for further research and may be used for fish resource monitoring and management.

Diversity of Parasitic Animals in Hypersaline Waters: A Review

Hypersaline waters are unique polyextreme habitats, where the salinity limits species richness. There are main patterns of a relationship between salinity and the species richness of free-living aquatic animals, but for parasitic organisms, general regularities have not yet been established. There are quite numerous data on parasites in hypersaline waters worldwide; however, they have not been summarized before. This review tries to fill this gap by summarizing the available data. All parasites, 85 species and forms, found in hypersaline waters belong to five phyla: Platyhelminthes, Nematoda, Acanthocephala, Cnidaria, and Arthropoda. Platyhelminthes are the most diverse phylum with the highest species richness in class Cestoda. Most species were noted in hypersaline waters with a salinity of no more than 100 g·L−1. The total number of parasitic species decreases exponentially with an increase in salinity. The number of free-living animal species inhabiting waters with a salinity from 35 to 210 g·L−1 is approximately 12 times higher than that of parasitic ones in all intervals of this salinity range. Salinity influences parasite richness and composition in two ways—directly and through the availability of hosts. Free-living crustaceans were hosts of most parasite species in hypersaline waters. Artemia spp., the most halotolerant animals, are an intermediate host for 22 species and unidentified forms of parasites.

A repeated cross-sectional study of intestinal parasites in Texas shelter dogs using fecal flotation and saline sedimentation.

Estimates of intestinal parasite prevalence in canine populations have largely been based on use of fecal flotation methods only. Dogs in animal shelters are likely at higher risk of intestinal parasite infection because of their previous exposure history. Our objectives were to estimate the prevalence of intestinal parasites among Texas shelter dogs using centrifugal fecal flotation and saline sedimentation techniques, to identify risk factors for infection, and to compare proportions of positive samples detected via fecal flotation vs. saline sedimentation for the most common parasites. Using a repeated cross-sectional study design, we collected fecal samples from dogs on three visits to each of seven Texas animal shelters between May 2013 and December 2014. Fecal flotation and/or saline sedimentation were used to identify parasites in samples. Fecal samples were collected from 529 dogs. The most frequently detected parasites were Ancylostoma caninum (26.4% via fecal flotation, 20.7% via saline sedimentation) and Trichuris vulpis (12.0% via fecal flotation, 14.1% via saline sedimentation). Risk factors for certain parasites were identified; for example, dogs with abnormal fecal consistency were more likely to be shedding T. vulpis eggs than dogs with normal fecal consistency (OR = 1.8, p = 0.005). The addition of fecal sedimentation not only added to the number of parasite species detected in this study, but it also increased the number of dogs diagnosed with the common intestinal parasites that are primarily detected using fecal flotation methods. Texas shelter dogs carry a high burden of intestinal parasites, including those of zoonotic importance.

18S rRNA Gene-Based Piroplasmid PCR: An Assay for Rapid and Precise Molecular Screening of Theileria and Babesia Species in Animals.

PurposeThe parasites of genera such as Babesia and Theileria are called piroplasmids due to the pear-shaped morphology of the multiplying parasite stages in the blood of the vertebrate host. Because of the enormous number of parasite species and the challenges of multiplex PCR, initial screening of samples using piroplasmid-specific PCR may be a more cost-effective and efficient technique to identify parasite species, especially during epidemiological studies. Accordingly, 18S rRNA PCR was standardized and optimized on common piroplasmids of different animals like cattle, buffaloes, sheep, goats, dogs, horses, and leopards.MethodsBloods samples from 1250 animals were collected from different animals in Junagadh district of Gujarat, India. 18S rRNA PCR was standardized and optimized as a primary method for molecular screening of piroplasms in domestic and wild animals. The method was checked for its analytical sensitivity and specificity. Parasite species-specific PCR and sequencing was used to validate the test. Moreover, in-silico restriction enzyme (RE) analysis was also done to assess its applicability in PCR–RFLP.ResultsPiroplasm infections were recorded in 63.3% of animals in Junagadh. The 18S rRNA PCR detected the piroplasmid DNA in as low as 39 picograms (pg) of whole blood genomic DNA isolated from microscopically Theileria positive blood samples and no reactivity was recorded from common but unrelated haemoparasites viz., Trypanosoma evansi, Hepatozoon spp., Anaplasma spp., and Ehrlichia canis was observed. The 18S rRNA PCR assay findings were confirmed by species-specific PCR and sequencing. Analysis of different sequences generated using 18S rRNA PCR revealed that the amplicon size of Babesia spp. is nearly 400 bp (393–408 bp) whereas Theileria spp. were more than 400 bp (418–424 bp). The percentage of sequence divergence among Babesia and Theileria spp. was 7.3–12.2% and 0.7–12.2%, respectively. In-silico restriction enzyme (RE) analysis reveals the presence of at least one site for a commercially available RE in 18S rRNA fragments of every parasite, which can differentiate it from its congeners.ConclusionsThe presented universal oligonucleotide-based PCR assay provides a highly sensitive, specific, cost-effective, and rapid diagnostic tool for the initial screening of piroplasmids infecting domestic and wild animals and is potentially helpful for large-scale epidemiological studies.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11686-022-00625-2.

Видовая структура гельминтоценозов каменной куницы (Martes foina) и лесной куницы (Martes martes) на Северо-Западном Кавказе

The article is devoted to the study of the species structure of the helminthocenoses of the stone and forest martens, conducted from 2006 to 2022. 55 corpses of stone martens from the foothill landscape-geographical zone and 64 corpses of forest martens from the foothill and mountain zones of the North-West Caucasus were examined. The analysis of the results of the study showed that the main factor in the formation of helminthocenoses of martens in the study region is the species structure of trophic and epizootic circuits, such links are given predators, and species which play the role of intermediate, additional and reservoir hosts of parasites. During the study period, an increase in the number of parasite species in the structure of helminthocenoses of martens was noted. We associate this fact with the anthropogenic transformation of natural ecosystems and the violation of historically established biocenotic relationships, the main of which is the «parasitehost » system. The marten species living in the study region form and support 15 natural foci of helminthiasis in the North-West Caucasus, including the focus of trichinosis.

Паразиты рыб горных озер бассейна Верхней Колымы. 1. Озера большой и малый Дарпир.

The first data on the parasite fauna of fish from the mountain lakes Bolshoy and Maly Darpir at the southern spurs of the Chersky Ridge (Momsky District, Yakutia) are presented. 7 species of fish have been studied, in which 34 species of parasites have been found: 33 species of helminths and 1 species of parasitic copepods, belonging to 22 genera, 16 families, 12 orders, 7 classes of 4 types of the animal kingdom. Trematodes completely dominate by the number of species among helminths (16 species); cestodes are half as many (8 species); these are followed by nematodes and spiny-headed worms (5 and 4 species, respectively). The greatest variety of parasites was found in the East Siberian grayling (22 species) and the Arctic char (19 species). Next to the latter in terms of the number of parasite species, there went the Kolyma sculpin (13 species), round whitefish (10 species each), sucker (9 species), eelpout, and common minnow (7 species each). Only one parasite species, the Neoechinorhynchus salmonis Ching, 1984 spiny-headed worm, is common for all studied fish. The second species of spiny-headed worms, Pseudoechinorhynchus borealis (Linstow, 1901), not found only in the round whitefish, was first recorded in fish of the Okhotsk-Kolyma area and in the sucker as a new definitive host.

The main stages of development of agricultural nematology

Goal. Analyze the biological patterns underlying the principles of creating methods for monitoring and control of nematodes of field crops and woody plants, as well as the possibility of creating biological products based on EPN from local strains identified by the laboratory of nematology.
 Methods. Analysis of the results of laboratory developments for 30 years of research.
 Results. The high level of the number of parasitic species of nematodes (200—800 individuals in 100 cm3 of soil) has a significant impact on the growth, development and yield of the main field and flower ornamental crops. Losses can reach 35—55% of biomass (or ornamental) crops and 20—30% of the crop. Agrocenoses are more sensitive than natural coenoses to changes in the environment. Due to this, such agrotechnical measures as crop rotation, species and varietal composition of crops in crop rotation, fertilization system, tillage methods, etc. significantly affect the population density of parasitic nematodes, so they can be used to regulate their numbers. According to the results of laboratory tests in Ukraine, the pine wood nematode B. mucronatus was found, which is the cause of suppression and drying of Scots pine plantations. Methods for monitoring this new species of phytoparasitic nematodes have been developed. Long-term studies of the spread of entomopathogenic nematodes in Ukraine have made it possible to identify three species that quite densely (21.2% of the analyzed samples) inhabit the habitats of Ukraine, show high effectiveness against soil and other pests, so are promising for biopreparations based on entomopathogenic nematodes.
 Conclusions. The use of methods developed in the laboratory for monitoring and controlling the number of populations of phytopathogenic nematodes will keep the damage from this group of pathogens at a low level, preserving up to 20—30% of the crop, and prevent drying of coniferous forests from bursaphelenchosis.

Health status and microbial quality of common carp reared in a pond fed with treated wastewater from a slaughterhouse

Wastewater from slaughterhouses in many countries is still discharged into rivers, without having been adequately treated. Such wastewater contains plenty of organic matter which is an ideal source of nutrients for fish, but also for the development of microorganisms. Thus, usage of wastewater in aquaculture could become a health risk for humans, fish due to the introduction of microorganisms into the aquatic environment. In the available literature, there is insufficient data on health and meat safety regarding common carp reared in purified wastewater. The aim of this study was to assess the health and meat safety of common carp cultivated in a fishpond supplemented with slaughterhouse wastewater that was subjected to tertiary treatment. The number of parasites was not significant and not a single parasitic disease was found in this study, but the number of parasite species detected was as expected and typical for carp production. No spring viraemia of carp or koi herpesvirus disease was found. The carp cultivated were in good health and completely safe for human consumption in terms of the presence of microbial contaminants. The safe use of wastewater for fish rearing should be encouraged, but proper treatment of wastewater must be applied before its use.

PRIMER REGISTRO DE SPINITECTUS RODOLPHIHERINGI VAZ & PEREIRA, 1934 (SPIRURIDA: CYSTIDICOLIDAE) EN AUCHENIPTERUS NUCHALIS (SPIX & AGASSIZ, 1829) (SILURIFORMES: AUCHENIPTERIDAE) DE LOS LAGOS DE LA LLANURA ALUVIAL DEL AMAZONAS

Fish are the vertebrates that have the greatest number and diversity of parasitic species. Auchenipterus nuchalis (Spix & Agassiz, 1829) is a small fish that occurs in South America, popularly known as “Peruvian mandi”. It has twilight habits and its diet is basically composed of aquatic insects and microcrustaceans, which are intermediate hosts of several parasitic species. Although fish are the vertebrate group with the highest number of parasitic species, most of these species are still unknown, therefore, the main objective of this study was to know and identify the Nematoda species that parasitize A. nuchalis and calculate the parasitological indices of each species. 38 A. nuchalis were captured in four expeditions in September, October, November and December 2016, in the Catalao lake complex in the municipality of Iranduba, Amazonas, on the left bank of the Solimoes river and on the right bank of the Negro river, Brazil. The fish measured, on average, 11.8 - 18 (15.1 ± 1.35) cm in standard length and weighed 30.1 – 71.0 (47 ± 10.66) g. The individuals' digestive tract was preserved in 70% ethanol and transported to the laboratory for analysis. Of the total fish collected and examined, 31 were parasitized. Temporary and permanent slides were mounted to identify the parasitic specimens. The measurements of the individuals were made with the aid of a micrometric eyepiece, coupled to an optical microscope. Eighteen individuals of Spinitectus rodolphiheringi Vaz & Pereira, 1934 parasitizing the intestine and stomach of the hosts were collected. Presenting an infection prevalence rate of 26.3%, which characterizes it as a satellite species. Furthermore, this is an unpublished record of this parasite for A. nuchalis and for the Amazon region.

Metazoan Parasite Infracommunities of the Tomtate Grunt (Haemulon aurolineatum) as Potential Bioindicators of Environmental Conditions in the Yucatan Continental Shelf, Mexico.

Metazoan parasites and their hosts experience the environmental influence of the seasonal presence of Western and Eastern subzones with different oceanographic conditions on the Yucatan continental shelf (YS). In addition, natural seeps and oil transport in the area lead to the presence of hydrocarbons. We hypothesized that the parasite infrapopulations and infracommunities of Haemulon aurolineatum will respond to environmental variability related with ongoing oceanographic subzone conditions of the YS. Spatial and multivariate statistical analyses were used to test this hypothesis. For 17 sampling sites along the YS, 55 parasite morphospecies were recovered from 146 fishes. There were significant differences in the number of parasite species between Western and Eastern subzones, but not in the number of parasite individuals. Spatial autocorrelation on environmental variables as a consequence of the Yucatan current was found. Overall, the parasite metrics suggested a region with a good ecosystem health condition naturally influenced by oceanographic processes.

STUDY OF TOXICOLOGICAL PROPERTIES AND LOCAL IRRITANT EFFECT OF THE DRUGS INSACAR TOTAL C PLUS AND INSACAR TOTAL K PLUS ON LABORATORY RATS

The study of acute cutaneous toxicity and local irritant effect of the drugs Insacar Total C Plus and Insacar Total K Plus on mongrel white rats was conducted in doses of 5000 and 10 000 mg/kg of body weight (BW). When the drugs were applied to the skin of rats, no animal deaths were recorded during the entire observation period. Thus, the LD50 is more than 10 000 mg / kg of BW. A single application of the drugs to the skin in rats at a dose of 1 ml/100 g (10 000 units) in two experimental groups on the 7th and 9th day of the study showed the most pronounced irritant effect. In this regard, the drugs have an irritating effect – 1 point. The studied drugs Insacar Total C Plus and Insacar Total K Plus belong to the group of insectoacaricidal and anthelmintic agents. The substances included in its composition have a contact and systemic effect on ectoparasites and nematodes. They are complex medicines containing 4 active components – moxidectin, pyriproxifen, imidacloprid, praziquantel. Such a combination of active substances is characterized by effectiveness against a larger number of parasite species, stages of their development, and in addition, reduce the likelihood of developing resistance of pathogens to drugs.

Myxosporeans (Phylum Myxozoa) Parasitic on Some Fishes from Hamrin Lake in Diyala Province, Iraq

Between January and December 2019, a total of 368 fish specimens were collected from Hamrin lake in Diyala province, Iraq. These fishes belonged to 16 species: Acanthobrama marmid, Alburnus caeruleus, A. sellal, Arabibarbus grypus, Carasobarbus luteus, Carassius auratus, Chondrostoma regium, Cyprinion kais, C. macrostomum, Cyprinus carpio, Garra rufa, Leuciscus vorax, Luciobarbus xanthopterus, Mastacembelus mastacembelus, Mystus pelusius and Planiliza abu. The result of inspection showed that these fishes were infected with 25 species of parasites belonging to the class Myxosporea. These included one species each of Chloromyxum and Unicauda, two species each of Myxidium and Thelohanellus and 19 species of Myxobolus. Among these parasites, Myxobolus pfeifferi infected the highest number of hosts (ten host species), followed by M. drjagini and M. oviformis (nine host species each), while five parasite species infected one host species each. Among these fishes, C. luteus was infected with the highest number of parasite species (18 species), followed by C. carpio (13 species). Myxobolus. hemibarbi was recorded in the present study for the first time in Iraq. The description and measurements of this parasite is presented. In addition, a total of 35 new host records in Iraq were reported for 18 species of these parasites.

Investigating the diversity of fish parasites in the floodplain of the upper Paraná River: a long-term ecological monitoring

Abstract: Aim The aim of this study was to present the description of new species of fish parasites in native and non-native hosts and the parasite interaction / host, available in studies for 37 years in the upper Paraná River floodplain. Methods The sampling described in this study is part of a scientometric methodology, in which specific query expressions were used, together with the database available in the Nupelia Sector Library, through Theses and Dissertations. Results A total of 44 species of parasites belonging to different groups were described for 27 species of fish of different orders. In these 37 years of studies, an increase 68% was observed in the number of parasite species, presenting a richness of 201 species in the floodplain, being: Monogenea, Digenea, Nematoda and Cestoda are the groups that present the largest records of species. More than 80 hosts have their parasite fauna registered and most studies are carried out with species of native hosts in the floodplain, being Prochilodus lineatus the host with the highest number of records. Conclusions Parasitological studies are an important scientific tool for understanding the dynamics of ecological interactions in the natural environment, and knowledge of this diversity of organisms is continuous and necessary, and the results of the monitoring carried out in the floodplain during the last 37 years only reinforce this with a constant increase in the description of new species and new records of parasite-host interactions. In times of constant environmental loss and habitat fragmentation, it is of utmost importance to care for and preserve floodplains to maintain biodiversity.

Evolutionary Signature of Ancient Parasite Pressures, or the Ghost of Parasitism Past

Animals adopt a range of avoidance strategies to reduce their exposure to parasites and the associated cost of infection. If strong selective pressures from parasites are sustained over many generations, avoidance strategies may gradually evolve from phenotypically plastic, or individually variable, to fixed, species-wide traits. Over time, host species possessing effective infection avoidance traits may lose parasite species. Indeed, if overcoming the avoidance strategies of a host species is too costly, i.e. if individuals of that species become too rarely encountered or difficult to infect, a generalist parasite may opt out of this particular arms race. From the host’s perspective, if avoidance traits are not costly or have been co-opted for other functions, they may persist in extant species even if ancestral parasites are lost, as signatures of past selection by parasites. Here, we develop the ‘ghost of parasitism past’ hypothesis. We discuss how animal species with a lower number of parasite species than expected based on their ecological properties or phylogenetic affinities are a good starting point in the search for traces of past parasite-mediated selection. We then argue that the hypothesis explains the dynamic and inconsistent nature of the relationship between the expression of avoidance traits and relative infection risk in comparative analyses across host species. Finally, we propose some approaches to test the predictions of the hypothesis. Animal morphology and behavior show clear evidence of past selective pressures from predators; we argue that past selection from parasites has also left its imprint, though in more subtle ways.