Morphological and molecular identification of the metacestode parasitizing the liver of rodent hosts in bamboo growing areas of mizoram, northeast India

Morphological and phylogenetic analysis of Raillietina spp. indigenous chickens (Gallus gallus domesticus) in Bangladesh

Raillietina spp. (Cestoda: Davaineidae), the most common cestodes in indigenous chickens, cause a substantial production loss in poultry industry in Bangladesh. Here, we estimated the prevalence, confirmed the species and determined the genetic pattern of species of Raillietina using molecular tools. We collected and examined 375 chickens randomly from household of different villages of Mymensingh sadar and Gouripur upazila, Mymensingh district and adult parasites were isolated and identified. Genomic DNA was extracted from collected parasites, amplified ITS-2 and ND-1 genes, sequenced and analyzed. Out of 375 samples, 270 (72.0%) were found positive with Raillietina species and mean worm burden was 10.46 ± 0.56. Microscopically, three species of Raillietina, such as R. cesticillus (37.9%), R. echinobothrida (41.1%) and R. tetragona (52.8%) were detected on the basis of their morphological features. The total length, length and width of scolex, sucker and rostellum were also measured. Among different factors, age, farming nature and flock size of chickens were significantly (p < 0.05) influenced Raillietina infections. For further validation, the sequences of ITS-2 gene generated in this study were matched with reference sequences of R. cesticillus, R. echinobothrida and R. tetragona and found 99.63% - 100% similarity. The phylogenetic analyses of ITS-2 and ND-1 sequences were clustered together with the reference sequences of R. cesticillus, R. echinobothrida and R. tetragona confirming microscopic identification. This is the first confirmation of species of Raillietina along with the prevalence of the species, which will be helpful for the formulation of a control strategy and provide basic information for further molecular study.

Comparative Comprehensive Analysis on Natural Infections of Hymenolepis Diminuta and Hymenolepis Nana in Commensal Rodents

This first comprehensive report from Punjab province of India relates to patho-physiological alterations alongwith morpho-molecular characterisation and risk assessment of natural infections of Hymenolepis diminuta and Hymenolepis nana in 291commensal rodents including house rat, Rattus rattus (n=201) and lesser bandicoot rat, Bandicota bangalensis (n=90). Small intestine of 53.61 and 64.95 % rats was found infected with H. diminuta and H. nana, respectively with a concurrent infection rate of 50.86 %. There was no association between male and female rats and H. diminuta and H. nana infections (ᵡ² = 0.016 and 0.08, respectively, d.f.= 1, P>0.05), while the host age had significant effect on prevalence of H. diminuta and H. nana (ᵡ² = 28.12 and 7.18, respectively, d.f.= 1, P≤0.05) infection. Examination of faecal samples and intestinal contents revealed globular shaped eggs of H. diminuta without polar filaments (76.50 ± 3.01μm x 67.62 ± 2.42 μm), while smaller sized oval eggs of H. nana were with 4 – 8 polar filaments (47.87 ± 1.95 μm x 36.12 ± 3.05 μm). Cestode infection caused enteritis, sloughing of intestinal mucosa, necrosis of villi and inflammatory reaction with infiltration of mononuclear cells in the mucosa and submucosa. Morphometric identification of the adult cestodes recovered from the intestinal lumen was confirmed by molecular characterisation based on nuclear ITS-2 loci which showed a single band of 269 bp and 242 bp for H. diminuta and H. nana, respectively. Pairwise alignment of the ITS-2 regions showed 99.46 % similarity with sequences of H. diminuta from USA and 100 % similarity with sequences of H. nana from Slovakia, Kosice.

A parasitological survey of zoonotic cestodes carried by house rats in Aswan, Egypt, reveals cryptic diversity at the molecular level

Background and Aim:

Some rat cestodes are zoonotic and are capable of parasitizing humans and animals, raising serious concerns regarding human and veterinary health. The study aimed to determine the prevalence and risk factors for cestodes in Egyptian house rats and to characterize the cestodes molecularly.

Materials and Methods:

The current survey examined 115 house rats (Rattus rattus) in two cities (Edfu and Aswan) in Egypt’s Aswan Governorate for cestode infection using integrated molecular approaches (polymerase chain reaction, sequencing, and phylogenetic analysis) and morphological/morphometrical approaches.

Results:

The cestodes identified in this study exhibited the typical morphological characteristics of Hymenolepis diminuta (Rudolphi, 1819), Hymenolepis nana (Siebold, 1852) (from rat intestine), and Hydatigera taeniaeformis (from rat liver). The species prevalence rates from these three studies were reported to be 8.7%, 10.4%, and 20.9%, respectively. The ribosomal DNA (ITS1, 18S, and complete ITS) sequences revealed that the hymenolepid sequences were highly distinct but were related to other sequences in the GenBank database, with some sequences showing high similarities to those of H. nana and H. diminuta. In addition, the H. taeniaeformis sequences (ITS2 and mitochondrial cytochrome c oxidase subunit 1 [mtCOX1]) obtained in this study were highly similar to some Taenia taeniaeformis GenBank sequences. The constructed phylogram revealed that the hymenolepidid tapeworms examined in this study were classified into four major branches (the majority of which were hybrids of the two species) and belonged to the genus Hymenolepis. In addition, the phylogram of H. taeniaeformis assigned this species to T. taeniaeformis.

Conclusion:

When typical hymenolepid morphology is combined with molecular and phylogenetic divergence, it may indicate the existence of possible cryptic species. In addition, on the basis of the phylogenetic analysis, genetic diversity within T. taeniaeformis may exist as determined by comparing the metacestode mtCOX1 sequences. The current study presents the prevalence values of zoonotic cestodes and contributes to the body of knowledge, including identification keys and the use of molecular tools for species confirmation.

Hydatigera taeniaeformis in urban rats (Rattus rattus) in Faisalabad, Pakistan

Hydatigera taeniaeformis formerly referred to as Taenia taeniaeformis is a cestode of cats (definitive hosts) and rodents (intermediate hosts). The prevalence of the metacestode larval stage has been reported in rodents in many parts of the world even though the genetic polymorphisms or intraspecies variation is still understudied. Here, we report a prevalence of 22.09% (38/172) from an urban rodent population in Pakistan and a nucleotide diversity (cox1) of 0.00463 among the population. Infection was higher in male (27.85%) and adult (32.29%) rats than female and sub-adult/young rats. Interestingly, The median-joining network and phylogenetic construction comprising isolates from China, Japan, Kenya, Laos, Malaysia, Senegal, the United Arab Emirates, and countries in Europe demonstrated that Pakistani H. taeniaeformis are closer to Asian and African population than those of European origin. The results of the study will add-in preliminary data for H. taeniaeformis and will also contribute to understand the global molecular epidemiology and population structure of H. taeniaeformis.

Detection of Raillietina saudiae from the domestic pigeon in Saudi Arabia through 18S and 28S rDNA genes

Raillietina saudiae is a well-studied avian gastrointestinal parasite belonging to the family Davaineidae and is the most prevalent cyclophyllid tapeworm infecting pigeon in Saudi Arabia. The present study considered as a complementary analysis of Al-Quraishy et al. (2019; Parasitol Int 71, 59-72) with molecular studies for two ribosomal DNA genes employed for precise recognition of this Raillietina species. The annotated partial 18S and 28S rDNA gene regions were found to be 888 and 900 bp long that utilized further to elucidate their genetic relationships at species level using maximum likelihood method. The query sequence of R. saudiae is well aligned and placed within the Davaineidae family, with the same clade of all species of Raillietina that well separated from other cyclophyllidean cestodes especially taeniid and hymenolepid species. Sequence data recorded the monophyly of Raillietina species. The current phylogeny supports the usage of the partial 18S and 28S rDNA genes as reliable markers for phylogenetic reconstructions.

Morphological and molecular appraisal of cyclophyllidean cestoda parasite Raillietina saudiae sp. nov. infecting the domestic pigeon Columba livia domestica and its role as a bio-indicator for environmental quality

Pigeons members of the order Columbiformes are a cosmopolitan group of birds with abundant and large populations associated with human activities. Therefore, the current study was conducted to determine the parasitic infections within the domestic pigeon Columba livia domestica. Eighteen pigeons were examined for the presence of gastrointestinal helminths, of which 77.78% were infected with a cyclophyllidean cestoda parasites. The morphology of this parasite based on light and scanning electron microscopic studies, revealed the presence of gravid worms, 2.00-4.52 cm long and 0.23-0.59 mm wide; a scolex had four suckers equipped by 5-6 rows of minute hooks and retractable rostellum with 230-250 hooks; genital pores unilateral; oval testes with 27-37 in number; bilobed ovary; post-ovarian vitelline gland; and 24-28 egg capsules present in uterus with 5-6 spherical eggs in each capsule. Molecular analysis based on sequences of ITS2 and ND1 gene regions was performed to confirm the taxonomy of this parasite based on its morphology. This revealed close identity of up to 92.0% and 72.0% for ITS2 and ND1 gene regions, respectively, with other cestoda species obtained from GenBank. Phylogenetic analysis supported the placement of this cycllophylid species within Davaineidae with close relationships to the previously described species of R. chiltoni, R. dromaius, and R. beveridgei based on the ITS2 gene region and R. coreensis and R. sonini based on the ND1 gene regions. Heavy metals accumulation in the recovered parasite and its host showed significantly higher concentrations in the parasite compared to its host tissues. Generally, concentrations of metals exceeded the permissible limits recommended by the US Environmental Protection Agency. Therefore, pigeon cestodes can be regarded as useful bio-indicators when evaluating the environmental pollution of terrestrial ecosystems by heavy metals.

DNA barcoding of metacestodes found in the Guerlinguetus ingrami (Rodentia: Sciuridae) reveals the occurrence of Hydatigera taeniaeformis sensu stricto (Cyclophyllidea: Taeniidae) in the Americas

The existence of cryptic species in the genus Hydatigera, cyclophillid cestodes, mainly of felids, was recently described based on molecular studies of parasites from Asia, Europe and Africa. However, the occurrence of H. taeniaeformis sensu stricto (s.s.), the species more widely distributed and with a presumed specificity for murid rodents as intermediate hosts, has not been formally described in Americas. In the present study, during necropsy of an Ingram's squirrel specimen, Guerlinguetus ingrami, found dead in the municipality of Belo Horizonte, Minas Gerais state, Brazil, strobilocerci were found in the liver. The metacestodes were subjected to morphological and molecular studies. Sequences of the COI barcode region were obtained and used for phylogenetic analyses. The morphology and measures of the rostellar hooks were compatible with the ones described for H. taeniaeformis s.s. This identification was confirmed by a molecular phylogenetic approach (96.2-99.7% similarity with isolates of the parasite from Europe and Asia). This is the first molecular confirmation of the existence of H. taeniaeformis s.s. on the American continent. Moreover, the involvement of sciurid rodents in the transmission of H. taeniaeformis s.s. is discussed here as a probable case of parasite spillover.

Morphology and Molecular Phylogeny of Raillietina spp. (Cestoda: Cyclophyllidea: Davaineidae) from Domestic Chickens in Thailand

Raillietina species are prevalent in domestic chickens (Gallus gallus domesticus) in Phayao province, northern Thailand. Their infection may cause disease and death, which affects the public health and economic situation in chicken farms. The identification of Raillietina has been based on morphology and molecular analysis. In this study, morphological observations using light (LM) and scanning electron microscopies (SEM) coupled with molecular analysis of the internal transcribed spacer 2 (ITS2) region and the nicotinamide adenine dinucleotide dehydrogenase subunit 1 (ND1) gene were employed for precise identification and phylogenetic relationship studies of Raillietina spp. Four Raillietina species, including R. echinobothrida, R. tetragona, R. cesticillus, and Raillietina sp., were recovered in domestic chickens from 4 districts in Phayao province, Thailand. LM and SEM observations revealed differences in the morphology of the scolex, position of the genital pore, number of eggs per egg capsule, and rostellar opening surface structures in all 4 species. Phylogenetic relationships were found among the phylogenetic trees obtained by the maximum likelihood and distance-based neighbor-joining methods. ITS2 and ND1 sequence data recorded from Raillietina sp. appeared to be monophyletic. The query sequences of R. echinobothrida, R. tetragona, R. cesticillus, and Raillietina sp. were separated according to the different morphological characters. This study confirmed that morphological studies combined with molecular analyses can differentiate related species within the genus Raillietina in Thailand.

Clinico-pathology, diagnosis and management of Cysticercus fasciolaris and Hymenolepis diminuta co-infection in wistar rats

Aim:

The present study was undertaken to study the pathology and control of sudden unexplained mortality in wistar rats.

Materials and Methods:

This study was conducted in a colony of 25 male wistar rats where there was mortality of nine rats. The dead rats were subjected to thorough post-mortem examination and necropsy samples were processed for hematoxylin and eosin staining for histopathological studies. Faecal samples of live rats were studied for the presence of parasitic eggs. Treatment with anthelmintics was given to manage the mortality and infections.

Results:

The investigation revealed a natural co-infection of Cysticercus fasciolaris and Hymenolepis diminuta in wistar rats, which were pathogenic enough to cause mortality. Typical lesions associated with the parasites were found in the dead rats. The mortality and infection were managed with common anthelmintics.

Conclusion:

C. fasciolaris and H. diminuta infection can cause mortality in wistar rats even when individually they cause asymptomatic infection. The mortality and infection can be managed with common anthelmintics.

[Morphological and molecular identification of Cysticercus fasciolaris isolated from rodent hosts (Rattus norvegicus) in Buenos Aires province (Argentina)]

In a rodent (Rattus norvegicus) survey in Buenos Aires province, metacestodes of tapeworms were found encysted in the liver of the host. The aim of this work was the morphological and molecular identification of this parasite. To achieve the molecular characterization of the parasite, ribosomal (28S) and mitochondrial (COI) DNA were amplified and sequenced. Based on both morphological and molecular data using bioinformatic tools, the metacestode was identified as Cysticercus fasciolaris. The adult form of this tapeworm (Taenia taeniaeformis) commonly infects felid and canid mammalian hosts. This is the first report on the molecular identification of Cysticercus fasciolaris in Buenos Aires province (Argentina).