Animal Parasites Research Articles

Meguro Parasitological Museum – A Wonderful Experience Full of Surprises

In November 2023, one of us had the opportunity to visit the Meguro Parasitological Museum in Tokyo, Japan. The museum started its journey in 1953 with private funding from Dr Satoru Kamgeai. Now, the museum is a 70-year-old private research facility with its researchers who not only collect parasites of various animals for studies on morphology, taxonomy, distribution of parasites, etc. but also give presentations at academic meetings and publish articles in academic journals.

Intestinal Parasites Associated with American Cockroach (Periplaneta americana) in Akure, Ondo State, Nigeria.

American cockroach (Periplaneta americana) has been implicated as mechanical vector of parasites of humans and animals. Therefore, this study aimed to identify and determine the prevalence of human intestinal parasites associated with the body surface and gut of P. americana. A total of 221 cockroaches which include 104 males and 117 females were collected from household kitchen, toilet area and canteen after which they were brought to laboratory for study. The body surface of the cockroach was washed with 5ml normal saline solution to remove external parasites on the body surface for examination and later rinsed with 70% alcohol and dried before dissecting. The cockroach was dissected to examine internal parasites. Eleven parasites were recovered and identified, these include Ascarislumbricoides (51.58%),Strongyloides stercoralis (48.42%) Trichuristrichiura (52.49%),Enterobiusvermicularis (37.10%), Taenia spp (14.93%),Toxocara(31.67%), Ancylostoma spp (34.84%), Necator americanus (53.39%), andDiphylidium spp(66.23%) Balantidium coli (66.52%). The parasites were recorded both on the body surface and gut of the cockroach. There is no significant difference (p > 0.05) between parasites infection rate comparing both sexes; though, female cockroach having a higher infection rate (91.45%) than male (81.5%). Cockroach collected from toilets carried more parasites (96.34%) as compared to those from restaurants/canteen (89.71%) and household kitchens (81.69%). All parasites encountered were pathogenic to human and animals. This study has revealed that P. americana can act as mechanical vector by transporting and transmitting these parasites easily to man and animal. Good sanitary practices, reinforcement of worms' eradication programs, and the fight against these insects remain a necessity to contain the menace of parasites burden and cockroach control.

Apical annuli are specialised sites of post-invasion secretion of dense granules in Toxoplasma.

Apicomplexans are ubiquitous intracellular parasites of animals. These parasites use a programmed sequence of secretory events to find, invade, and then re-engineer their host cells to enable parasite growth and proliferation. The secretory organelles micronemes and rhoptries mediate the first steps of invasion. Both secrete their contents through the apical complex which provides an apical opening in the parasite's elaborate inner membrane complex (IMC) - an extensive subpellicular system of flattened membrane cisternae and proteinaceous meshwork that otherwise limits access of the cytoplasm to the plasma membrane for material exchange with the cell exterior. After invasion, a second secretion programme drives host cell remodelling and occurs from dense granules. The site(s) of dense granule exocytosis, however, has been unknown. In Toxoplasma gondii, small subapical annular structures that are embedded in the IMC have been observed, but the role or significance of these apical annuli to plasma membrane function has also been unknown. Here, we determined that integral membrane proteins of the plasma membrane occur specifically at these apical annular sites, that these proteins include SNARE proteins, and that the apical annuli are sites of vesicle fusion and exocytosis. Specifically, we show that dense granules require these structures for the secretion of their cargo proteins. When secretion is perturbed at the apical annuli, parasite growth is strongly impaired. The apical annuli, therefore, represent a second type of IMC-embedded structure to the apical complex that is specialised for protein secretion, and reveal that in Toxoplasma there is a physical separation of the processes of pre- and post-invasion secretion that mediate host-parasite interactions.

Seasonal dynamics of freshwater gastropods in central zone of Kashmir Valley, India

The present study was carried out to study the prevalence and seasonal distribution of snail fauna in central zone of Kashmir valley. A total of 12,103 snails were collected during September 2017 to August 2018 and 10 snail species under 5 genera recorded were Physa acuta, Lymnaea lagotis f. costulata, L. stagnalis, L. brevicauda, auricularia var obliquata, L. luteola f. typica, Gyraulus ladacensis, G. pankogensis, Bithynia troscheli and Indoplanorbis exustus. Besides this, one unidentified snail was also reported. Species-wise overall prevalence was observed highest for P. acuta (18.65%), followed by L. lagotis (15.54%), L. stagnalis (13.31%), G. ladacensis (11.49%), L. brevicauda (10.19%), B. troscheli (8.00%), L. auricularia (6.94%), I. exustus (5.32%), L. luteola (5.15%), G. pankogensis (3.42%) and lowest for unidentified snail (1.94%). Prevalence of snails was found to be highest in summer (53.81%) followed by spring (29.76%), autumn (15.66%) and lowest in winter season (0.75%), the difference being statistically significant between seasons. Overall F% and RF% of snails was observed to be highest for P. acuta followed by Lymnaea spp. other than L. stagnalis, Gyraulus spp., B. troscheli, I. exustus and lowest for unidentified snail. Overall F% and RF% of snails was also observed highest in summer followed by spring, autumn and lowest in winter season. Based on RF%, all snails were found highly distributed, except for unidentified snail, which was found to be lightly distributed. The study concluded that Physa snails were found highly prevalent. Knowledge of the particular snail and cercariae released by them could be used to formulate control strategy to reduce the burden of trematode parasites in animals. Unidentified snail recorded in this study appears to be new species, which needs further detailed investigation.

Getting around the roundworms: Identifying knowledge gaps and research priorities for the ascarids.

The ascarids are a large group of parasitic nematodes that infect a wide range of animal species. In humans, they cause neglected diseases of poverty; many animal parasites also cause zoonotic infections in people. Control measures include hygiene and anthelmintic treatments, but they are not always appropriate or effective and this creates a continuing need to search for better ways to reduce the human, welfare and economic costs of these infections. To this end, Le Studium Institute of Advanced Studies organized a two-day conference to identify major gaps in our understanding of ascarid parasites with a view to setting research priorities that would allow for improved control. The participants identified several key areas for future focus, comprising of advances in genomic analysis and the use of model organisms, especially Caenorhabditis elegans, a more thorough appreciation of the complexity of host-parasite (and parasite-parasite) communications, a search for novel anthelmintic drugs and the development of effective vaccines. The participants agreed to try and maintain informal links in the future that could form the basis for collaborative projects, and to co-operate to organize future meetings and workshops to promote ascarid research.

Toxoplasma gondii chitinase-like protein TgCLP1 regulates the parasite cyst burden.

Toxoplasma, an important intracellular parasite of humans and animals, causes life-threatening toxoplasmosis in immunocompromised individuals. Although Toxoplasma secretory proteins during acute infection (tachyzoite, which divides rapidly and causes inflammation) have been extensively characterized, those involved in chronic infection (bradyzoite, which divides slowly and is surrounded by a cyst wall) remain uncertain. Regulation of the cyst wall is essential to the parasite life cycle, and polysaccharides, such as chitin, in the cyst wall are necessary to sustain latent infection. Toxoplasma secretory proteins during the bradyzoite stage may have important roles in regulating the cyst wall via polysaccharides. Here, we focused on characterizing the hypothetical T. gondii chitinase, chitinase-like protein 1 (TgCLP1). We found that the chitinase-like domain containing TgCLP1 is partially present in the bradyzoite microneme and confirmed, albeit partially, its previous identification in the tachyzoite microneme. Furthermore, although parasites lacking TgCLP1 could convert from tachyzoites to bradyzoites and make an intact cyst wall, they failed to convert from bradyzoites to tachyzoites, indicating that TgCLP1 is necessary for bradyzoite reactivation. Taken together, our findings deepen our understanding of the molecular basis of recrudescence and could contribute to the development of novel strategies for the control of toxoplasmosis.

Investigação e estudo genotípico sobre a infecção de camundongos selvagens Blastocystis sp. em Guangdong e Chongqing

ABSTRACT Blastocystis are common digestive tract parasites in humans and animals, extensively parasitic in humans and other primates. They exhibit extensive genetic diversity; Currently, 17 subtypes (STs) and some populations called non mammalian and avian STs (NMASTs) have been proposed. To understand the infection status and genotype distribution of Blastocystis sp. in wild mouse, this study used PCR technology to study the fecal DNA samples of 111 Leopoldomys edwardsi and 117 Berylmys bowersi collected from Guangdong and Chongqing. Among 228 fecal samples, 4 samples were positive for Blastocystis sp., with a total infection rate of 1.8% (4/228). Four positive samples formed two subtypes of ST3 and ST4, all of which were zoonotic genotypes. This article aims to investigate the infection status and genotype distribution of wild mouse Blastocystis sp., which will help reduce the infection of this pathogen to animals and thereby reduce their risk of zoonotic transmission.

Adaptive Enhancement Network with Border Injection for Animal Parasite Eggs Detection

Adaptive Enhancement Network with Border Injection for Animal Parasite Eggs Detection

Prevalence of intestinal parasites in children and domestic animals from two peri-urban neighborhoods in northeastern Argentina.

Motivation for the study. There are few reports on intestinal parasites in children and domestic animals in urban areas in Argentina who live in homes with characteristics that favor the maintenance and transmission of parasites of zoonotic importance. Main findings. More than 50% of children and pets were parasitized, most of them with zoonotic pathogens. Implications. Our results showed the urgent need to improve sanitary control of children and animals, and to implement activities for the prevention of intestinal parasitosis in the homes analyzed.

Induction of Programmed Cell Death in Acanthamoeba culbertsoni by the Repurposed Compound Nitroxoline.

Acanthamoeba is a ubiquitous genus of amoebae that can act as opportunistic parasites in both humans and animals, causing a variety of ocular, nervous and dermal pathologies. Despite advances in Acanthamoeba therapy, the management of patients with Acanthamoeba infections remains a challenge for health services. Therefore, there is a need to search for new active substances against Acanthamoebae. In the present study, we evaluated the amoebicidal activity of nitroxoline against the trophozoite and cyst stages of six different strains of Acanthamoeba. The strain A. griffini showed the lowest IC50 value in the trophozoite stage (0.69 ± 0.01 µM), while the strain A. castellanii L-10 showed the lowest IC50 value in the cyst stage (0.11 ± 0.03 µM). In addition, nitroxoline induced in treated trophozoites of A. culbertsoni features compatibles with apoptosis and autophagy pathways, including chromatin condensation, mitochondrial malfunction, oxidative stress, changes in cell permeability and the formation of autophagic vacuoles. Furthermore, proteomic analysis of the effect of nitroxoline on trophozoites revealed that this antibiotic induced the overexpression and the downregulation of proteins involved in the apoptotic process and in metabolic and biosynthesis pathways.

Diversity, prevalence and risk factors associated to gastrointestinal tract parasites in wild and domestic animals from Pakistan.

The gastrointestinal tract (GIT) of animals contains various helminth parasites, responsible for subclinical and clinical parasitism. The health situation of animals is seriously affected by these parasites and leads massive financial losses for the livestock trade. The present study was conducted to determine the prevalence and associated risk factors of GIT parasites in small and large ruminants of Mardan district and zoo animals of Golden Life Safari Park Khyber Pakhtunkhwa. A total of 419 fecal samples were collected including 117 from goats, 110 from cattle, 80 from sheep, 66 from buffaloes, 40 from birds, four from deer, and two from leopards. The fecal samples were subjected to sedimentation and floatation to identify parasite eggs. Of a total of 419 fecal samples, 215 (51.31%) were found positive for GIT parasites eggs. The prevalence of GIT parasites was high in sheep (65%), followed by goats (62.39%), cattle (42.70%), and buffaloes (37.87%). In birds, GIT parasite eggs were identified in 11 (45.83%) and 7 (43.75%) fecal samples of Pheasant and Peacock, respectively. However, an absence of infection was noted in fecal samples from deer and leopards. Eggs of GIT Parasites belonging to one superfamily and four different genera were recognized in fecal samples of domestic animals and buffaloes, which were Trichostrongyloidea (19.81%), Strongyloides (9.31%), Trichuris (7.77%), Monezia (6.44%), and Fasciola (4.53%). For bird, the coccidia group comprises the highest representation of parasites (2.63%), followed by the Trichuris genus (1.67%). Settlement, management system, anthelminthic medications and body condition score were significantly associated with the occurrence of GIT parasites in feces (P < 0.05). Animals from rural settlements, rearing under poor management systems, with thin (poor) body condition and under warmed were more affected by GIT parasites. The diversity and the high prevalence of GIT parasites reported in this study highlights the urgent need for intervention through treatment and modification of management practices in the investigated areas of Pakistan.

Skrining Fasciolosis Pada Hewan Qurban Di Palangka Raya

Fasciola sp. a parasite which impacts ruminants including cattle, cause of the zoonotic disease fascioliosis. This study aims to describe the fasciolosis parasite in sacrificial animals on the Palangka Raya University campus in July–August 2023. This research is a descriptive exploratory study by examining the feces and livers of 15 samples of sacrificial animals with native methode. The results of the diagnosis of fasciolosis are based on the presence of Fasciola sp. eggs in the feces of sacrificed animals and the discovery of the parasite Fasciola sp. in the liver during post-mortem examination. The development of liver lesions in the form of inflammation and calcification brought on by the existence of Fasciola sp. was a defining characteristic of positively infected liver samples by worm infestations. Fasciola sp. eggs were found in the fecal samples with ovoid morphological characteristics, having an operculum at one pole, thin and smooth walls, and yellowish brown. The presence of Fasciola sp. being influenced by environmental factors, it is also heavily influenced by management factors, the majority of breeders in Palangka Raya take grass in watery areas where there are snails as intermediate hosts. This information can be a recommendation to the livestock service and to breeders to provide feed that is free of hosts and metacercariae of Fasciola sp. in Palangka Raya City.

Spliceosomal introns in the diplomonad parasite Giardia duodenalis revisited.

Complete reference genomes, including correct feature annotations, are a fundamental aspect of genomic biology. In the case of protozoan species such as Giardia duodenalis, a major human and animal parasite worldwide, accurate genome annotation can deepen our understanding of the evolution of parasitism and pathogenicity by identifying genes underlying key traits and clinically relevant cellular mechanisms, and by extension, the development of improved prevention strategies and treatments. This study used bioinformatics analyses of Giardia mRNA libraries to characterize known introns and identify new intron candidates, working towards completion of the G. duodenalis assemblage A strain 'WB' genome and further elucidating Giardia's gene expression. By using a set of experimentally validated positive control loci to calibrate our intron detection pipeline, we were able to detect evidence of previously missed candidate splice junctions directly from expressed transcript data. These intron candidates were further studied in silico using NMDS (non-metric multidimensional scaling) clustering to determine shared characteristics and their relative importance such as secondary structure, splicing efficiency and motif conservation, and thus to refine intron models. Results from this study identified 34 new intron candidates, with several potential introns showing evidence that secondary structure of the mRNA molecule might play a more significant role in splicing than previously reported eukaryotic splicing activity mediated by a reduced spliceosome present in G. duodenalis.

Multiple parallel origins of parasitic Marine Alveolates

Microbial eukaryotes are important components of marine ecosystems, and the Marine Alveolates (MALVs) are consistently both abundant and diverse in global environmental sequencing surveys. MALVs are dinoflagellates that are thought to be parasites of other protists and animals, but the lack of data beyond ribosomal RNA gene sequences from all but a few described species means much of their biology and evolution remain unknown. Using single-cell transcriptomes from several MALVs and their free-living relatives, we show that MALVs evolved independently from two distinct, free-living ancestors and that their parasitism evolved in parallel. Phylogenomics shows one subgroup (MALV-II and -IV, or Syndiniales) is related to a novel lineage of free-living, eukaryovorous predators, the eleftherids, while the other (MALV-I, or Ichthyodinida) is related to the free-living predator Oxyrrhis and retains proteins targeted to a non-photosynthetic plastid. Reconstructing the evolution of photosynthesis, plastids, and parasitism in early-diverging dinoflagellates shows a number of parallels with the evolution of their apicomplexan sisters. In both groups, similar forms of parasitism evolved multiple times and photosynthesis was lost many times. By contrast, complete loss of the plastid organelle is infrequent and, when this does happen, leaves no residual genes.

Updates on Emerging and Evolving Gastrointestinal Parasites in Dogs and Cats

Gastrointestinal parasites are a common veterinary concern and pet owner conversation. Globally, parasite ranges and abundances are evolving, and various clinical management challenges in dogs and cats have emerged. Some of these are novel, such as hookworm multi-drug resistance, and others have been veterinary challenges for years, like Giardia's zoonotic potential. For these examples and others, there has been increased awareness of the need for appropriate veterinary anthelmintic use and stewardship. This review provides an update on selected gastrointestinal parasites of One Health importance, highlights gastrointestinal parasite global management and prevention recommendations, and summarises recent research, along with potential risks associated with pet importation and travel. Suggestions on freely available online resources to assist with practical veterinary clinical management (screening, diagnosis, treatment, prevention) and pet owner communication, along with addressing One Health and antiparasitic stewardship concerns, are provided from a global perspective, for example The European Scientific Counsel for Companion Animal Parasites. Clinical cases are drawn from molecular diagnostic faecal surveillance of dogs and cats during 2022 and 2023, and include the following gastrointestinal parasites with zoonotic potential: hookworms (Ancylostoma caninum), tapeworms (Echinococcus multilocularis), roundworms (Baylisascaris procyonis) and Giardia.

The parasitic nematode Strongyloides ratti exists predominantly as populations of long-lived asexual lineages

Nematodes are important parasites of people and animals, and in natural ecosystems they are a major ecological force. Strongyloides ratti is a common parasitic nematode of wild rats and we have investigated its population genetics using single-worm, whole-genome sequencing. We find that S. ratti populations in the UK consist of mixtures of mainly asexual lineages that are widely dispersed across a host population. These parasite lineages are likely very old and may have originated in Asia from where rats originated. Genes that underly the parasitic phase of the parasite’s life cycle are hyperdiverse compared with the rest of the genome, and this may allow the parasites to maximise their fitness in a diverse host population. These patterns of parasitic nematode population genetics have not been found before and may also apply to Strongyloides spp. that infect people, which will affect how we should approach their control.

Toxoplasma ceramide synthases: Gene duplication, functional divergence, and roles in parasite fitness.

Toxoplasma gondii is an obligate, intracellular apicomplexan protozoan parasite of both humans and animals that can cause fetal damage and abortion and severe disease in the immunosuppressed. Sphingolipids have indispensable functions as signaling molecules and are essential and ubiquitous components of eukaryotic membranes that are both synthesized and scavenged by the Apicomplexa. Ceramide is the precursor for all sphingolipids, and here we report the identification, localization and analyses of the Toxoplasma ceramide synthases TgCerS1 and TgCerS2. Interestingly, we observed that while TgCerS1 was a fully functional orthologue of the yeast ceramide synthase (Lag1p) capable of catalyzing the conversion of sphinganine to ceramide, in contrast TgCerS2 was catalytically inactive. Furthermore, genomic deletion of TgCerS1 using CRISPR/Cas-9 led to viable but slow-growing parasites indicating its importance but not indispensability. In contrast, genomic knock out of TgCerS2 was only accessible utilizing the rapamycin-inducible Cre recombinase system. Surprisingly, the results demonstrated that this "pseudo" ceramide synthase, TgCerS2, has a considerably greater role in parasite fitness than its catalytically active orthologue (TgCerS1). Phylogenetic analyses indicated that, as in humans and plants, the ceramide synthase isoforms found in Toxoplasma and other Apicomplexa may have arisen through gene duplication. However, in the Apicomplexa the duplicated copy is hypothesized to have subsequently evolved into a non-functional "pseudo" ceramide synthase. This arrangement is unique to the Apicomplexa and further illustrates the unusual biology that characterize these protozoan parasites.

Molecular identification of Eimeria spp. and Eimeria bovis in water buffaloes, Iraq

Eimeria is a protozoan parasite of many wild and domestic animals including buffaloes resulting in a widespread disease known as coccidiosis that may impact production, well fare and health status. This study was designed to identify the prevalence of Eimeria spp. and E. bovis in buffaloes using conventional molecular technique. An overall 281 buffaloes of different sexes and ages of many rural areas in Wasit province were subjected during November (2022) to February (2023) to direct collect of fecal samples from the rectum. After molecular examination of all fecal samples by polymerase chain reaction (PCR), the results showed that 25.98 and 35.62% buffaloes were positive to Eimeria spp. and E. bovis, respectively. Furthermore, significant prevalence of Eimeria spp. being higher in  1 year than older ones and Al-Kut than other study region, but not between females and males; while, E. bovis was more prevalent in  1 year, Al-Kut and Al-Hay, and females. Additionally, values of odds ratio and relative risk were elevated significantly in  1 year female buffaloes of Al-Kut region. From our point of view, this represents the first molecular study identifies E. bovis in buffaloes from Iraq. In conclusion, molecular based-PCR revealed a high efficacy in identification of E. bovis, and can be used in epidemiological investigations of coccidiosis in entire country. However, we suggest that the DNA sequence variation in ITS1 region of different Eimeria species should be conducted to view genetic mutations as well as genetic association with other worldwide strains. Also, extensive investigation is necessary to bridge the knowledge gap and providing for diagnosis this parasite in buffaloes as well as in other field animals. Keywords: Coccidiosis, PCR, Bubalus bubalis, calf, wasit province. Iraq

Molecular Detection of Microsporidia in Cattle in Jahrom, Iran

Background: Microsporidia are eukaryotic, single-celled intracellular parasites that can produce spores. Recently, they have been considered one of the opportunistic pathogens causing chronic diseases. There are more than 140 genera and 1200 species of microsporidia. Many human microsporidia are probably of zoonotic origin and are transmitted by contaminated water with animal feces. Given the zoonotic importance of this parasite and its ability to be transmitted from animals to humans, diagnosing and determining the species of parasite would seem essential for health strategies. Methods: Two hundred fecal samples of slaughtered cows were collected from the Jahrom abattoirs from February 2021 to January 2022 and examined by molecular methods, including polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP-PCR). Results: From the 200 samples examined by PCR, 19 (9.5%) samples tested positive for microsporidia, of which 17 isolates were Enterocytozoon bieneusi and two isolates were Encephalitozoon cuniculi. Conclusion: The results revealed that microsporidia were present in cow feces. In addition, these findings indicated that cows can be considered a source of contamination for microsporidia. Given that this disease is a zoonosis, it is highly important to pay attention to the presence of this parasite in domestic animals that are in contact with humans. Further studies must be performed in different regions and different animals to understand the epizootiology of the pathogen. Eventually, the wide host range of microsporidia necessitates accurate identification of species and genera in all hosts all over the world.

Genetic characteristics of Blastocystis sp. ST3 at the genome level in the Chinese population.

The gut microbiota comprises the collective genomes of microbial symbionts and is composed of bacteria, fungi, viruses, and protists within the gastrointestinal tract of a host. Although the literature associated with gut microbiota is increasing, studies on eukaryotes in the human gut are just beginning to surface. Blastocystis is one of the most common intestinal parasites of humans and animals and is estimated to colonise more than 1 billion people on a global scale. However, the understanding of the genetic characteristics of Blastocystis subtype (ST) at the genome level and its relationship with other members of the gut microbiota is still limited. In this study, by surveying the prevalence and genome characteristics of Blastocystis sp. ST3 in a Chinese population (prevalence % = 6.09%), the association of Blastocystis sp. ST3 with region and time and the structure of the resident gut bacterial population was clarified. We identified novel sequences (50 mitochondrial and 41 genome sequences) and determined their genetic diversity amongst strains within Blastocystis sp. ST3 (4.14 SNPs/kb). Furthermore, we found that colonisation of Blastocystis was strongly associated with increased bacterial richness and higher abundance of several anaerobes. Finally, we performed time series sampling on two Blastocystis-positive individuals and confirmed that Blastocystis could exist continually in the human gut microbiota and persist for a long time, even for 4years.