Lymnaea Gedrosiana Research Articles

Trematode Cercariae from Lymnaea gedrosiana in the Caspian Sea Littoral in Iran: a one health concern.

Lymnaea gedrosiana snails are hosts to a variety of trematode cercaria of public and veterinary health importance. In Guilan Province, Iran, a region with a high level of fish and bird farming and wetlands important for migratory birds, little is known about the trematode cercaria from L. gedrosiana. From April 2020 to October 2021, six freshwater sites in Guilan Province were sampled for Lymnaeidae snails three times per season (spring, summer, autumn and winter). Snails were exposed to light and heat to induce cercaria shedding and shredded cercaria were identified morphologically and molecularly. In total, 5,712 Lymnaeidae snails were collected of which 3,288 (57.6%) were identified to be L. gedrosiana with 54.3% containing trematode cercaria. Snail and cercaria recovery were highest in the spring and summer. Trematode cercaria identified included Telorchis assula, Hypoderaeum conoideum, Apharyngostrigea pipientis, Sanguinicola cf. inermis, Opisthioglyphe ranae, Diplostomum pseudospathaceum, and Australapatemon burti. The four trematodes D. pseudospathaceum, S. inermis, A. burti, and A. pipientis have not been previously reported in Iran; all four of these can infect migratory birds. The most common cercaria found, H. conoideum (18.3% of the snails) is of zoonotic importance. The third most common cercaria found, S. inermis (10.0% of the snails) is detrimental to fish production. Given the importance of the wetlands in the region for wildlife and migratory birds as well as the number of fish and bird farms in the area, efforts to control L. gedrosiana snails are needed to protect wildlife and human health. In addition, monitoring programs should be implemented to identify and prevent introductions of new trematode species.

A faunistic survey of snails and their infection with digenean trematode cercariae in Bandar-e Anzali at the littoral of the Caspian Sea.

Trematodes are known as a diverse group of endogenous parasites, which snails as their intermediate hosts can dramatically affect parasite transmission dynamics. Snails play a key role in life cycles of digenean trematode. However, there has not been much faunistic surveys in terms of snails' distribution in Iran. The current study was aimed to identify snail's fauna and their current geographic distribution in four regions of Guilan province, Iran. Several species of snails (land and freshwater snails) were obtained from 4 different areas (2018-2019), and then samples were separately transferred to the laboratory. Diagnosis of snails was then performed according to morphometric characteristics including dextral or sinistral shell, shape, color and size of shell. Moreover, radula was stained and then photographed under microscopic examination. Furthermore, 25% of any species were tested for cercarial infection. In total, 2082 snails belonging to 12 species were identified based on the morphological characteristics. Land snails were identified to be Helicella sp. (46.4%), Helix aspersa (34.1%), Helicopsis sp. (8%), Pomatia sp. (6.7%) and Oxyloma elegans (4.8%). Moreover, freshwater snails were Physa acuta (30.6%), Lymnaea auricularia (25.8%), Lymnaea gedrosiana (18.7%), Lymnaea palustris (8.9%), Lymnaea truncatula (8.1%), Planorbis sp. (6.4%) and Lymnaea stagnalis (1.5%). In collected snails, Lymnaea auricularia (0.66%) and Lymnaea gedrosiana (0.45%) were the only snails harboring cercariae (Gymnocephalus cercariae). There was no statistically significant difference between the cercarial infection and snail species (P<0.05). Comprehensive field studies are highly needed for better evaluation of the snail biodiversity in the Caspian Sea region due to the particular climatic conditions and the high prevalence of trematodosis.

Identification and Determination of the Geographical Distribution of Freshwater Snails in Lorestan, Iran.

Snails are creatures present in various ecosystems that, in addition to being present in human surroundings, some of them are also important in veterinary medicine and medicine as the intermediate hosts of Digenean trematodes. The present study was conducted to identify and determine the geographical distribution of freshwater snails and investigate the relationship of variables, such as season and geographical region, with snail species and dispersion in Lorestan in the west of Iran. A total of 4400 samples of freshwater snails were collected using the multistage sampling method (i.e., stratified, cluster, and randomized) from 110 points in five geographical regions in four seasons and then identified based on their morphological characteristics by diagnostic keys. The ArcGIS software (version 10.3) was used to evaluate the spatial distribution of the freshwater snails. In this study, seven species of freshwater snails were identified in six families belonging to six genera, namely Melanopsis doriae (6.30% of the variation in species), Theodoxus doriae (5.55%), Bithynia tentaculata (43.22%, the dominant species), Physa acuta (24.98%), Lymnaea truncatula (9.75%), Gyraulus euphraticus (8.18%), and Lymnaea gedrosiana (2.02%). The geographic distribution of freshwater snails was recorded across five regions in 22 points per region for every season. The spatial distribution maps showed that the distribution of freshwater snails varies according to region and season (P&amp;lt;0.001). The obtained results revealed the effects of season and geographical region on the distribution and population density of snails in the province. These data can be used for the implementation of control programs against parasitic diseases in the region, including trematodes.

Avian Schistosomes and Human Cercarial Dermatitis in a Wildlife Refuge in Mazandaran Province, Northern Iran

Each year, hundreds of aquatic migratory birds migrate from northern hemisphere to the Mazandaran Province, northern Iran. Little information is available on prevalence and density of schistosomes in water birds in Iran and around the world. The objectives of this study were to determine definitive and intermediate hosts of avian schistosomes as well as to assess human cercarial dermatitis (HCD) in a wildlife refuge in Mazandaran Province. Of 1106 examined people, 589 (53.2%) had maculopapular rashes mainly on feet but also on hand. The majority of cases were adults and local residents. Of 260 ducks, 41 (15.8%) were found to be infected with Trichobilharzia spp. eggs or adult worms. Prevalence was highest in Anas clypeata and Anas platyrhynchos, 79% and 18.9%, respectively. A total of 1.2% snails, examined by both shedding and crushing methods, were infected with furcocercariae belonging to avian schistosomes. The most frequently infected snail was Lymnaea gedrosiana (5.9%). Our results showed that cercarial dermatitis and avian schistosomiasis is a common and yet neglected disease in this area. Anas clypeata played the most important role in exposing snails to miracidia in ponds and paddy fields. Moreover, because of the high prevalence in ducks and high prevalence of HCD in the region, it is considered as a new endemic focus in Iran.

Parasitological and molecular study of the furcocercariae from Melanoides tuberculata as a probable agent of cercarial dermatitis

Cercarial dermatitis is caused by animal schistosomes in many parts of the world including Iran. Various stages of the parasites have been studied in intermediate and definitive hosts in northern and southwestern Iran; however, no molecular investigation for species identification and classification of these agents has been carried out, so far. In the present study, more than 3,800 aquatic snails were collected from water sources of Khuzestan, southwest Iran. The snails were identified as Lymnaea gedrosiana, Radix auricularia, Melanoides tuberculata, Melanopsis sp. and Physa acuta. They were examined for schistosome cercariae. Two specimens of M. tuberculata were infected with ocellate furcocercariae belonging to the family Schistosomatidae. Molecular studies were carried on these schistosomatid samples. Both samples belong to an unknown schistosome species and genus in sister position to Gigantobilharzia-Dendritobilharzia clade. They differ from other species in their ITS sequence region as well as in their intermediate host specificity--This is one of the first reports on schistosome cercariae from M. tuberculata and the first including molecular data. Due to adaptability and invasiveness of this snail species, this new schistosome species, as a potential causative agent of cercarial dermatitis in humans, needs to be studied further.

A Faunistic Survey of Cercariae Isolated from Lymnaeid Snails in Central Areas of Mazandaran, Iran

The aim of this study was to elucidate the species diversity of larva trematodes in the Mazandaran Province, Northern Iran. In this cross-sectional study, a total of 3,266 lymnaeid snails from 3 species were collected from different parts of streams, swamps, rice fields and rivers in the central areas of Mazandaran Province (Sari, Neka, Qaemshahr and Savad-Koh cities), during April to September, 2008. The samples were tested by crushing and emerging methods. From the total of examined snails, 119 (3.6%) were found to be infected with the lymnaeid snails. Lymnaea gedrosiana were found to be infected with the Furcocercariae of Diplostomidae, Clinostomidae, Echinostomatidae and also cercariae of the Plagiorchiidae. The latest infection was found to be in L. palustris. The Mazandaran Province with its temperate climate is a suitable place for living of snails, particularly lymnaeidae, that could have a significant role as an intermediate host of diseases.

Detection of Ornithobilharzia turkestanikum cercaria (trematoda) by nested-PCR in intermediate host snail, Lymnaea gedrosiana

Trematodes are important in economic and public health. Ornithobilharzia turkestanicum (O. turkestanicum) is one of the important economic trematodes in domestic animals. Ornithobilharzia infection in intermediate host (Lymnaea gedrosiana ) can be detected by either exposing snails to light to induce cercarial shedding or by squeezing them between glass slides to detect parasites. The current available diagnostic methods are inefficient for identification of prepatent infections and/or after dead of snails. For the above difficulties we adapted a nested polymerase chain reaction (Nested-PCR) assay for sensitive detection of O. turkestanicum in clinical samples and its cercaria in snails. The life cycle of parasite was maintained in sheep and snails in laboratory in Razi Institute. Adult worms were isolated from sheep and DNA was extracted from worms by a procedure using DNA extraction solution developed in NIGEB. PCR and nested-PCR primers were designed based on 28s ribosomal RNA gene of O. turkestanicum and the DNA was amplified by PCR assay. PCR product was purified and cloned in pTZ57R/T and sequenced. The comparison of the obtained sequences with the GenBank using blast program was showed in NCBI Sequence viewer just 682 bp. PCR amplicon was submitted in GenBank and can be assessed using AY862391 accession number. DNA was extracted from the infected and non-infected snails 2-5 days post-infection. The infected snails could be rapidly detected with Nested-PCR. Results indicate that this assay is specific for detecting O. turkestanicum. The high sensitivity of the test enabled identification of single infected snail even when its DNA was pooled with uninfected snails. Thus demonstrating the possibility of mass diagnosis in pools of snails, therefore, the assay has the potential for large-scale demonstration of prepatent infection prevalence in snails and offers a new diagnostic tool for evaluation of bilharziosis trasnsmission and for control of infection as discussed.

A study on cercarial dermatitis in Khuzestan province, south western Iran.

BackgroundCercarial dermatitis' or swimmer's itch' is an itchy inflammatory response to the penetration of the skin by non-human schistosome parasites. In the hot season, (May to September) in Khuzestan province in the south west of Iran, swimming in canals and agriculture activities in swampy areas are common. This survey was made on people from villages north of Ahwaz city in south west Iran, to estimate cercarial dermatitis in this region.Methods2000 people were observed for clinical signs of cercarial dermatitis. Also 2000 Lymnaea gedrosiana snails were collected from agriculture canals and examined for animal schistosome cercariae during 1998–2000.ResultsFrom this survey 1.1% of people had pruritic maculopapular rash on their feet, hands or other parts of body. From the total of examined snails, 2.4% were found to be infected with bird schistosome cercariae including Trichobilharzia species.ConclusionCercarial dermatitis could be a health problem in this area. This is the first report of cercarial dermatitis from this region of Iran.

Suitability of six lymnaeid snails for infection with Fasciola hepatica

The suitability of Fossaria ( Bakerilymnaea) cubensis and Pseudosuccinea columella from Louisiana as intermediate hosts for Fasciola hepatica was compared to P. columella and Stagnicola elodes from Ann Arbor, MI, S. attenuata from Hidalgo, Mexico, Lymnaea gedrosiana from Iran and L. natalensis from Senegal. P. columella from LA was shown to be a more suitable host (51.3% became infected) than F. ( B) cubensis (15.2% and 26.4% of two populations became infected). The infection rate for P. columella from MI, was 50% and for L. gedrosiana was 32.5%, whereas L. natalensis, S. elodes and S. attenuata were refractory. F. (B) cubensis and P. columella have some degree of suitability as intermediate hosts for F. hepatica under laboratory conditions, but field observations of their habitat in southern LA and characteristic management of cattle indicate that the former snail is more important as an intermediate host in this enzootic area. Tissue sections of suitable snails had few histopathological effects but physical damage caused by rediae was pronounced, mainly in the digestive gland and in the mantle.

Dermatitis Caused by Cercariae of Orientobilharzia Turkestanicum in the Caspian Sea Area of Iran *

Cercarial dermatitis is very common among rice farmers in the Caspian Sea area of Iran. The characteristic eggs of Orientobilharzia turkestanicum were found in the feces of a plowing bull. Fifty-six percent of uninfected Lymnaea gedrosiana maintained at 24-25 degrees C produced cercariae, identical to those from natural infections, 21 days after exposure to the miracidia obtained from the feces of the bull. Cercariae of O. turkestanicum from naturally infected L. gedrosiana produced dermatitis on the arm of one of us.

The effect of variation in miracidial exposure dose on laboratory infections of Ornithobilharzia turkestanicum in Lymnaea gedrosiana

AbstractThe laboratory infection of Lymnaea gedrosiana with 1,2,5,10 and 20 miracidia of Ornithobilharzia turkestanicum, resulted in infection rates of 54.5%, 57.1%, 62.5%, 84.0% and 100% respectively, with a prepatent period of 18–21 days.The numbers of cercariae shed daily by single snails exposed to one or 2 miracidia were significantly lower than from those exposed to 5,10 or 20 miracidia.Few cercariae were shed during the early patent period, but the number increased with the duration of infection. All infected snails died at the peak of cercarial shedding, and no infected snails survived more than 60 days after exposure to miracidia. The differences between the mean life-span of infected snails and non-infected snails in the control group were statistically significant (P &lt; 0.001).

Observations on Lymnaea gedrosiana, the intermediate host of Ornithobilharzia turkestanicum in Khuzestan, Iran.

AbstractA study of the distribution and population of Lymnaea gedrosiana in relation to the transmission of Ornithobilharzia turkestanicum in various habitats was carried out in Khuzestan.Populations were higher in canals and swamps than in ponds, with peaks in spring and autumn and low densities in summer and winter.The reproductive capacity of L. gedrosiana was higher in running water than in stagnant water. The peak reproduction rates occurred in spring and autumn and reproduction continued at a low level in summer but was nil in winter.Infection with O. turkestanicum was higher in large than in small snails (0.1 %, 0.5% and 1.1% in snails measuring 0.6 mm, 6–10 mm and 10–14 mm respectively). In canals and swamps transmission occurred throughout the year, with a peak in late summer in the former and early summer in the latter. In ponds, most transmission probably occurred in spring and autumn. Drains played a very minor role in transmission.

Lymnaea gedrosiana, an Intermediate Host of Fasciola hepatica in Iran

The susceptibility of Lymnaea gedrosiana, a widespread snail in Iran, to Fasciola hepatica has been proven through two experiments. In the first experiment metacercariae collected from Lymnaea were fed to two white mice and two rabbits; the infection developed in both rabbits. In the second experiment the whole life-cycle of the parasite was completed by getting miracidia from eggs collected from infected liver of a buffalo and infecting laboratory-bred Lymnaea and producing metacercariae. The metacercariae were given to three rabbits, all of which became infected, and F. hepatica flukes were recovered from all animals. The economic importance of the common liver fluke as a health hazard to domestic animals was established years ago. Several hundred cases of human infection with this parasite have been recorded from all parts of the world (Pantelouris, 1965). In much of Iran infection rate of livestock is high. The livers of 1,302 domestic animals from the southern part of the country showed an overall prevalence of 31% (Sabbaghian et al., 1964). Buffalo had the highest rate of infection, 57%, with 54% for cows, and 35% for sheep in this area. Reports of human cases with this parasite in Iran are increasing (Sohrabi and Amini, 1967). During a survey for bilharziasis and other trematodes in Iran, an abundance of Lymnaea gedrosiana was observed in many parts of the country. In Khuzestan Province, located in the southwest of Iran, where urinary bilharziasis occurs among the human population, particularly in rural areas, L. gedrosiana is found with a high density in breeding places of Bulinus truncatus, the intermediate host of S. haematobium, S. bovis, and Paramphistomum in Iran (Arfaa, 1962; Arfaa et al., 1965b, 1967). L. gedrosiana is also the intermediate host of Ornithobilharzia turkestanicum, a trematode of domestic animals, prevalent in Iran (Arfaa et al., 1965a). Received for publication 16 October 1968. This study has been supported in part by the Institute of Public Health Research, School of Public Health, Teheran University, and in part by funds of Plan Organization and Ministry of Health for Project No. 63001. * School of Public Health, Teheran University. t Dezful Bilharziasis Research Station, Inst. of Public Health Research. * Institute of Public Health Research. MATERIALS AND METHODS 1. In the first trial, Lymnaea gedrosiana collected from the field were crushed and the cercariae released were permitted to encyst on the inner surface of the jar. These metacercariae were fed to two white mice and two rabbits. 2. A second trial was undertaken to complete the life cycle of the parasites in the laboratory. For this purpose the infected liver of a buffalo, from Dezful slaughter house, was crushed and the eggs of Fasciola were collected in a jar containing dechlorinated water. Miracidia which started to emerge 15 days later, were used for infecting laboratory-bred L. gedrosiana. Four hundred Lymnnaca were exposed, each to five miracidia, and were kept in jars with a water temperature ranging from 25 to 28 C. Cercariae shed were allowed to encyst on a polyethylene sheet and metacercariae so produced were kept in water for a period of 18 to 22 days. Different numbers of metacercariae were removed with a razor blade from the polyethylene sheet and given to three rabbits. Two methods were used for feeding metacercariae to the animals: In the first method metacercariae were collected in a dropper, counted, and directly given to the animal per os. In the second method metacercariae were collected on a small piece of lettuce which was given to the animal after starving it for 1 day. The number of metacercariae fed as well as the period elapsed between infection and autopsy varied for different animals. RESULTS AND DISCUSSION White mice infected in the first trial were autopsied 39 and 54 days after infection, but no flukes were found in their viscera, while rabbits infected during this trial and autopsied 67 days later, yielded three F. hepatica in the liver, and eggs in the bile duct of the first animal, and three flukes in the liver of the second rabbit. Results of the second trial were as follows: Autopsy of rabbits undertaken 50 to 69 days after infection revealed the presence of F.