Female Worms Research Articles

Year after year: Recurrent Toxocara vitulorum infections in American bison (Bison bison) calves in a zoo

Toxocara vitulorum (Nematoda: Ascaridida) is a common parasite of cattle and buffaloes in tropical and subtropical regions and the causative agent of toxocarosis in calves. In Europe, sporadic infections have been reported in cattle, but also in bovines held at zoological gardens. Here, we report T. vitulorum infections in a herd of American bison (Bison bison) kept at the Vienna Zoo, Au stria, which occurred in 2023 and 2024. After the first case in a seven-week-old calf in July 2023, another case in a five-week-old calf was diagnosed in May 2024, both of them detected by coproscopy and fecal discharge of adult worms after anthelmintic treatment. The calves originated from two different mothers imported to the zoo in 2014 from the Czech Republic and 2012 from Germany respectively. Both calves showed diarrhea and fecal soiling of the anal region prior to fecal analysis. Two intramuscular administrations of ivermectin (0.2 mg/kg bodyweight, two-week interval) caused the passing of up to 39 cm long gravid female worms, resulted in the cessation of egg shedding and improved fecal consistency. Morphological and molecular identification confirmed infections with T. vitulorum. Additionally, another calf, born in May 2024 from the mother of the calf that was T. vitulorum-positive in 2023, showed periods of diarrhea. Due to difficulties in taking individual samples, no definitive diagnosis of T. vitulorum infection could be made, however, the animal was also treated and clinically improved afterwards. Besides T. vitulorum, Eimeria spp. were detected in all samples and Giardia duodenalis genotype E in two samples in 2024. This case series highlights the possibility of unnoticed parasite introductions into zoological gardens via animals infected with resting parasite stages, and demonstrates the importance of regular individual parasitological analysis in bovine zoo animals during the first weeks after birth.

Spatial proteomics of Onchocerca volvulus with pleomorphic neoplasms shows local and systemic dysregulation of protein expression.

Onchocerca volvulus , the causative agent of onchocerciasis (river blindness), is targeted for elimination by WHO. The primary strategy involves mass administration of ivermectin. A small proportion of adult female worms develop pleomorphic neoplasms (PN). Here, we used laser capture microdissection and highly sensitive mass spectrometry analysis to determine the protein inventory of PN to identify proteins that may be associated with tumor development. Neoplasm tissue from female worms was analyzed, and compared to normal tissue from the body wall, uterus and intestine from the same worms, and to tissues from females without PN. When compared, PN and healthy control (HC) worms display a different set of proteins, the PN tissue being the one with the highest number of proteins (1,390). From these, 594 were not present in any HC worm tissue. Despite the large number of proteins identified in PN tissue, their low abundance suggests also in PN dysregulation of protein expression. Immunolocalization of a calcium binding protein detected in PN confirmed the mass spectrometry results. In conclusion, we have developed a system to analyze the proteome of O. volvulus from nodule sections and identified proteins that are potentially linked to the development of PN and may contribute to worm mortality.

Protein profile of extracellular vesicles derived from adult Parascaris spp.

BackgroundParascaris spp. represent a significant threat to equine health worldwide, particularly in foals. The long-term survival of parasites in the host necessitates persistent modulation of the host immune response. Intercellular communication achieved through the exchange of molecules via extracellular vesicles (EVs) released from the parasite could be a crucial factor in this regard. This study aimed to isolate and characterize EVs released by adult male and female Parascaris worms and conduct a proteomic analysis to identify sex-specific proteins and potential immunomodulatory factors.MethodsLive adult Parascaris worms were collected, and EVs were isolated from spent culture media using differential ultracentrifugation. Nanoparticle tracking analysis and transmission electron microscopy confirmed the size, concentration, and morphology of the isolated EVs. Proteins within the isolated EVs were analyzed using mass spectrometry-based proteomics (LC–MS/MS).ResultsProteomic analysis revealed a total of 113 proteins in Parascaris EVs, with several proteins showing homology to known helminth exosome proteins and exhibiting immunomodulatory functions. Sex-specific differences in EV protein composition were observed, with a distinct abundance of C-type lectins in female EVs, suggesting potential sex-specific roles or regulation. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses revealed metabolic pathways shared between male and female Parascaris EVs, as well as differences in signal transduction, and cell growth and death pathways, indicating sex-specific variations.ConclusionsThese findings imply that Parascaris EVs and their protein cargo are complex. This data potentially opens avenues for discovering innovative approaches to managing and understanding helminth infection.Graphical

Internalization of macromolecules into filarial parasites – Possible operation of host’s anti-fecundity immunity inside adult filarial nematodes

ObjectivesImmune effector mechanisms operating against large extracellular systemic pathogens, such as adult stages of filarial nematodes, are not clearly understood. The only immune effect on the adult worms appears to be directed towards embryos in adult worms. The role of IL-4 or TLR-4 in immune responses that inhibit embryogenesis in adult filarial worms has been well-documented. This host’s immune responses that control embryogenesis (anti-fecundity immunity) are considered critical and were addressed in the current study. The current investigation demonstrated the possible operation of anti-adult immunity that could be functional against large stage adults. MethodsAdult filaria worms were pulsed with macromolecules such as Concanavalin A, Human immunoglobulins, and Rabbit immunoglobulins for 6 hrs, and entry of these molecules was demonstrated using flow cytometry. Filaria worms were also preincubated with Latrunculin A, an endocytic inhibitor, to explain if macromolecules enter by endocytosis. ResultsUsing the flow cytometry approach, we could show the entry of immunoglobulins into the uterine cavity of female Setaria digitata, a cattle-dwelling filarial parasite. Immunoglobulins were observed to bind to the surface of intrauterine stages of female worms. We also demonstrated the presence of bovine immunoglobulins in different embryonic stages in situ. ConclusionsOverall, experimental evidence demonstrates the existence of the host’s immune molecules inside large-stage adult parasites. However, future studies are directed to understand the functional aspect of the presence of these effector molecules inside the adults.

Atomic force microscopy reveals morphological and mechanical properties of schistosoma mansoni tegument

Schistosoma mansoni, an intravascular parasitic worm and the causative agent of schistosomiasis, relies on its tegument (outer layer) for survival and host interaction. This study explored the morphology and mechanical properties of S. mansoni tegument using Atomic Force Microscopy (AFM). Notably, we employed the PeakForce Quantitative Nanomechanical Mapping (PF-QNM) mode in air, enabling simultaneous acquisition of 3D topography and mechanical property contrasts (adhesion, elastic modulus). Additionally, nanoindentation (AFM contact mode) was performed on female worm tegument for elastic modulus measurement. Both techniques revealed an elastic modulus range of fractions or units of GPa for the tegument. Interestingly, mechanical property maps, particularly adhesion contrast, displayed a recurring pattern of light and dark bands. We also measured the depth of annular furrows on the female tegument, finding an average of 128 ± 10 nm. These findings establish AFM, particularly PF-QNM, as a valuable tool to characterize S. mansoni tegument properties, offering insights for future investigations into parasite biology and its response to immunological or pharmacological challenges.

Updated annotation and meta-analysis of Brugia malayi transcriptomics data reveals consistent transcriptional profiles across time and space with some study-specific differences in adult female worm transcriptional profiles.

Genomics, transcriptomics, and proteomics have significantly advanced our understanding of obligately host-associated microbes, where interrogation of the biology is often limited by the complexity of the biological system and limited tools. This includes the causative agents of many neglected tropical diseases, including filarial nematodes. Therefore, numerous transcriptomics studies have been undertaken on filarial nematodes. Most of these transcriptomics studies focus on Brugia malayi, which causes lymphatic filariasis and is a laboratory model for human filarial disease. Here, we undertook a meta-analysis of the publicly available B. malayi transcriptomics data enabling the direct cross comparison of samples from almost a dozen studies. This reanalysis highlights the consistency of transcriptomics results across many different studies and experimental designs from across the globe for over a decade of research, across many different generations of a sequencing technology, library preparation protocols, and differential expression tools. Males and microfilariae across samples had similar expression profiles. However, female samples were clustered into two differential expression patterns that were significantly different from one another. Largely, we confirm previous results for all studies reanalyzed including tissue-specific gene expression and anti-Wolbachia doxycycline treatment of microfilaria. However, we did not detect previously reported differential expression upon in vitro or in vivo treatment with ivermectin, albendazole, and DEC, instead identifying a consistent lack of transcriptomic change upon exposure to these anthelminthic drugs. Updated annotation has been provided that denotes poorly supported genes including those overlapping rRNAs.

An Overview of Parasitic Disease: Dracunculiasis

Dracunculiasis, also known as guinea worm disease, is a parasitic illness that only affects isolated, rural communities without access to clean drinking water in thirteen sub-Saharan African countries. The WHO has identified it as one of the next diseases to be eradicated. Water contaminated with copepods, or water fleas, carrying Dracunculiasis medinensis larvae is the vector of guinea worm disease transmission. A year after humans consume contaminated water, an adult female worm emerges, usually from a lower extremity, causing excruciating ulcers that can cause severe mobility impairment for several weeks. This illness strikes during the height of agricultural activity every year. A village's economically productive population is typically impacted in large numbers at the same time, which lowers agricultural output and causes economic difficulties. Since there is no known cure or vaccine for guinea worm disease, prevention is the key to its eradication. Globally, guinea worm disease cases have decreased by 98% since 1986, mostly due to community-based initiatives. Through these initiatives, the community has been taught how to filter water to get rid of parasites and how to stop people who have ulcers from contaminating drinking water sources. Sustained high-level political, financial, and community support will be necessary for complete eradication. By using an ayurvedic treatment approach, dracunculiasis can also be prevented. Ayurvedic medicine uses a few medicinal plants that exhibit antiparasitic activity against dracunculiasis, including Neem, Turmeric, Garlic, Amala, Baheda, Harde, Vidanga, Gokshura, Rasna, Bilva root, and Bala root.

Intranasal Linguatula serrata (tongue worm) in canids and vulpids can be detected using computed tomography.

Linguatula serrata ("tongue worm") is a zoonotic intranasal parasite found globally in wild dogs, free-ranging dogs, some domestic dogs, and vulpids. Since there are no sensitive tests currently available, infections are underdiagnosed. This is a pilot observational prospective study aimed at determining whether nasal linguatulosis can be diagnosed using CT. The secondary aims were to evaluate radiography, rhinoscopy, and nasal egg swabs as methods in the diagnosis of tongue worms. Fifty-four wild canids and three vulpids euthanased by gunshot were sourced from pest-control officers. Cadaver heads were subjected to helical CT examination, nasal-swabbed for tongue worm eggs, and necropsied. Radiographs and rhinoscopy were performed on cadavers suspected to be infected based on preliminary CT examination. Tongue worms were retrieved at necropsy in 25 dogs and one fox. CT findings in animals with no nasal cavity ballistic damage were reviewed in six infected dogs and one infected fox. Adult female tongue worms were identified in 4 of 6 dogs and 1 of 1 fox as long, tubular, slightly heterogeneously attenuating structures in the mid to caudal nasal cavities. They were not clearly visible in CT scans when surrounded by nasal fluid, and small parasites (male and immature females) were not discernible. Radiographic findings were mild and nonspecific. One tongue worm was detected in 1 of 12 dogs examined rhinoscopically. Tongue worm eggs were found in swabs from 7 of 25 dogs. While small tongue worms could not be detected with CT, CT proved to be a useful diagnostic method for visualizing adult female tongue worms.

Schistosomicidal effects of histone acetyltransferase inhibitors against Schistosoma japonicum juveniles and adult worms in vitro.

Schistosomiasis is a relatively neglected parasitic disease that afflicts more than 250 million people worldwide, for which the control strategy relies mainly on mass treatment with the only available drug, praziquantel (PZQ). This approach is not sustainable and is a priority for developing novel drug candidates for the treatment and control of schistosomiasis. In our previous study, we found that DW-3-15, a kind of PZQ derivative, could significantly downregulate the expression of the histone acetyltransferase of Schistosoma japonicum (SjHAT). In this study, several commercially available HAT inhibitors, A485, C646 and curcumin were screened in vitro to verify their antischistosomal activities against S. japonicum juveniles and adults. Parasitological studies and scanning electron microscopy were used to study the primary action characteristics of HAT inhibitors in vitro. Quantitative real-time PCR was employed to detect the mRNA level of SjHAT after treatment with different HAT inhibitors. Our results demonstrated that curcumin was the most effective inhibitor against both juveniles and adults of S. japonicum, and its schistosomicidal effects were time- and dose dependent. However, A485 and C646 had limited antischistosomal activity. Scanning electron microscopy demonstrated that in comparison with DW-3-15, curcumin caused similar tegumental changes in male adult worms. Furthermore, both curcumin and DW-3-15 significantly decreased the SjHAT mRNA level, and curcumin dose-dependently reduced the SjHAT expression level in female, male and juvenile worms. Among the three commercially available HATs, curcumin was the most potent against schistosomes. Both curcumin and our patent compound DW-3-15 markedly downregulated the expression of SjHAT, indicating that SjHAT may be a potential therapeutic target for developing novel antischistosomal drug candidates.

Artemisitene shows superiority over artemisinin in preventing Schistosoma japonica-induced liver disease

BackgroundArtemisinin (ART) analogs, such as dihydroartemisinin, arteether, artemether, and artesunate, all featuring an endoperoxide bridge, have demonstrated efficacy against schistosomiasis. Artemisitene (ATT), which contains an additional α, β-unsaturated carbonyl structure, has shown enhanced biological activities. This study aims to evaluate the anti-schistosomaiasis japonica activity of ATT and compare it with ART.MethodsWe assessed liver inflammation and fibrosis in mice using hematoxylin and eosin staining and Sirius red staining, respectively. RNA sequencing analyzed transcriptomics in female and male Schistosoma japonicum (S. japonicum) adult worms and mice livers, with cytokine profiling and flow cytometry to study immune responses under ART or ATT treatment.ResultsATT exhibits a marked reduction in female S. japonicum adult worms and egg numbers, damaging the adult worms’ surface. It also influences the transcription of genes related to cellular anatomical structures. Notably, ATT treatment resulted in significant reductions in liver granuloma size and collagen area, alongside lowering serum levels of glutamic pyruvic and glutamic oxaloacetic transaminase more effectively than ART. Both ART and ATT markedly decreased neutrophil frequency in the liver and elevated eosinophil counts. However, only ATT treatment significantly reduced the M1/M2 and Th1/Th2 indices, indicating a pronounced shift in immune response profiles. ATT-affected host immunity correlated with the extent of liver fibrosis and the count of single males more strongly than ART.ConclusionATT, as a novel preventive strategy for schistosomiasis japonica in mice, significantly outperforms ART.Graphical

First Molecular Identification and Clinical Presentation of Crenosomosis in a Dog from Slovakia

PurposeCrenosoma vulpis (Dujardin,1845) is a lungworm which has spread worldwide in canines and is associated with upper respiratory infections. In a majority of cases, the infections are accompanied with chronic cough. Diagnosis of lungworms is often underdiagnosed and can be misinterpreted as other respiratory diseases.MethodsThe Small Animal Clinic of the University Veterinary Hospital admitted an 11-month-old dog presented with persistent cough associated with difficulty in breathing and even asphyxia. Based on clinical symptoms, the patient underwent radiological and bronchoscopic examination. Bronchoscopy revealed the presence of lungworms obturating the branches of the tracheobronchial tree. Larvae were collected by bronchoscopic lavage and subjected to parasitological and molecular examination.ResultsMicroscopic detection and morphological identification of the worms removed during the bronchoscopy confirmed the presence of female adult worms. The subsequent molecular characterisation of the mitochondrial (cytochrome c oxidase subunit I gene (cox1) and 12S ribosomal DNA (rDNA)), nuclear (18S rDNA) genes, as well as the analysis of the second internal transcribed spacer (ITS-2) region of the ribosomal DNA, confirmed the Crenosoma vulpis species. Faecal samples were processed using the Baermann method, which confirmed the presence of the larval stage 1 of C. vulpis. The therapy with fenbendazole at a dose of 50 mg/kg of live weight once daily for the period of 7 days was initiated for the patient.ConclusionThis paper presents the first molecularly confirmed clinical case of a Crenosoma vulpis infection in an 11-month-old female dog of the Miniature Schnauzer breed in Slovakia.

Vulvovaginitis due to Enterobius vermicularis in a girl and epidemic enterobiasis in her family

Key Clinical MessageHere we present a case of a 4‐year‐old girl who suffered from vulvovaginitis caused by Enterobius vermicularis. All members of her family were also infected by this helminth. Treatment with mebendazole was administered to all family members and it was found that the entire family had been cured.AbstractVulvovaginitis, an inflammation of the vulvovaginal mucous membranes, is a common reason for pediatric gynecology consultations. One of the causes of this condition is a parasitic worm known as Enterobius vermicularis (E. vermicularis). In girls, adult worms can infiltrate the vagina and release eggs, leading to the development of vulvovaginitis. Furthermore, these worms have the ability to invade the endometrial cavity too. Here we present a case of a 4‐year‐old girl who suffered from vulvovaginitis caused by E. vermicularis. All members of her family were also infected by this parasitic helminth. In the vaginal sample, apart from the eggs, the female adult worm was observed under the microscope. Treatment with mebendazole was administered to all family members, and their progress was followed for a period of 3 weeks, during which it was found that the entire family had been cured. This patient experienced significant improvement in symptoms related to severe anxiety, nervousness, vaginal inflammation, itching, and vulvovaginitis caused by E. vermicularis. To prevent infection by E. vermicularis, it is crucial to disinfect underwear and bed sheets. In kindergartens, the spread of this parasite should not be underestimated, and asymptomatic individuals who have been exposed to infected persons should receive treatment to prevent an epidemic. Maintaining cleanliness and hygiene, especially after using the toilet, is of the most importance, particularly for girls who are more susceptible to E. vermicularis infection. Additionally, it is essential for all family members to be aware of the transmission routes of this parasite.

Analysis of Protection and Immune Response against Teladorsagia circumcincta in Goats Immunised with Thiol-Binding Proteins from Adult Worms.

In view of the increasing occurrence of anthelmintic-resistant strains of gastrointestinal nematodes in ruminants, various alternative control strategies have been investigated, such as those based on the induction of protective immune responses by immunisation with parasite antigens. In this study, the protective activity of somatic antigens from adult worms of Teladorsagia circumcincta purified by affinity chromatography on thiol-sepharose was analysed in goats. After challenge, the enriched products induced a slight reduction in the cumulative faecal egg counts (21%) and in the number of worms (23.3%), with a greater effect on female worms, which also showed a reduction in parameters related to their fertility. These parasitological findings were associated with a Th2 immune response, with a prominent local humoral response and an eosinophilic infiltrate in the gastric mucosa (negatively associated with the fertility of female worms and the number of worms, respectively), as well as an infiltration of MCHII+, CD4+, IgG+ and IgA+ cells. However, several analyses showed an increase in CD8+ cells in the mucosa, as well as IL-2 expression in the gastric lymph nodes, which may have been associated with inhibition of protective responses or with the development of mixed Th1/Th2 responses, a finding that should be analysed in future studies.

Autochthonous Ascariasis, Mississippi, USA.

We describe a case of a 2-year-old child who expelled a single adult female Ascaris lumbricoides worm. The patient is from a rural county in Mississippi, USA, with no reported travel outside of the United States. The caregivers in the home practice good sanitation. Exposure to domestic pigs is the likely source of infection.

Hepatocyte nuclear factor 4 located in different developmental stages in Schistosoma japonicum and involved in important metabolic pathways

Nuclear receptors (NRs) are vital for regulating gene expression un organisms. Hepatocyte nuclear factor 4 (HNF4), a class of NRs, participates in blood feeding and intestinal maintenance in schistosomes. However, there is limited research on the molecular and functional characterization of HNF4 in Schistosoma japonicum (S. japonicum). Highly specific polyclonal antibodies were generated to analyze the expression and tissue localization of S. japonicum HNF4 (SjHNF4). The potential biological functions of SjHNF4 were characterized by transcriptome and pull-down analysis. Subsequently, enrichment analysis was performed to identify the specific signaling pathways linked to SjHNF4. The SjHNF4 protein was expressed heterologously and purified successfully. High purity and high potency polyclonal antibodies were further prepared. The expression of SjHNF4 was higher in female compared to male worms at both transcriptional and protein levels. Female worms expressed SjHNF4 in their perithecium, reproductive system, and certain parts of the intestinal tissues. SjHNF4 was also detected in the perithecium of male worms, as well as in the head, body of cercaria, and eggs. Furthermore, our findings highlighted the potential role of SjHNF4 in blood feeding and its interaction with crucial pathways such as glucose metabolism, lipid metabolism, and nucleotide metabolism. This study shed light on the location of SjHNF4 in different life stages of S. japonicum, particularly associated with the female schistosomes. A strong correlation was observed between SjHNF4 and essential metabolic pathways. These findings laid a solid groundwork for the research on the relationship between NRs and schistosomes.

Growth hormone stimulates the in vitro development and establishment of Haemonchus contortus in sheep

The physiologic increase in some sex hormones has been associated with an increase in the parasite load caused by Haemonchus contortus in ewes, especially prolactin. In lambs that are especially susceptible to hemonchosis, the levels of sex hormones are low; in contrast, the levels of another pituitary hormone, growth hormone (GH), which is structurally very similar to prolactin, are high. In this study, the in vitro and in vivo effects of GH on H. contortus larvae development and establishment were evaluated. The addition of 20 ng/mL GH for 5 and 10 days to cultures of H. contortus larvae induced an enlargement (p<0.01) and an L3/L4 molting rate (p<0.03) greater than that of untreated larvae or those treated with other concentrations of the hormone. Flow cytometry showed that 3.8% of the largest and most complex cells of newly obtained larvae of H. contortus were positive for the GH receptor, and by immunofluorescence with confocal microscopy, it was observed that these receptors are located in the intestinal region larvae. In the in vivo assay, the administration of recombinant GH to gonadectomized lambs produced an increase in FEC (p<0.03), the number of female adult worms in the abomasum (p<0.05) and the levels of specific antibodies (p<0.04) in relation to the control lambs; however, it did not affect the fertility of H. contortus females. Although many factors affect the development and implantation of H. contortus in the abomasum of sheep, the results of this study strongly suggest that GH participates in the development and establishment of the parasite in sheep, mainly in young sheep.

Sanguinarine: an alkaloid with promising in vitro and in vivo antiparasitic activity against different developmental stages of Schistosoma mansoni and in silico pharmacokinetic properties (ADMET).

The objective of the study was to evaluate the in vitro and in vivo schistosomicidal activity of sanguinarine (SA) on Schistosoma mansoni and its in silico pharmacokinetic parameters. ADMET parameters and oral bioavailability were evaluated using the PkCSM and SwissADME platforms, respectively. The activity of SA in vitro, at the concentrations of 1.0-25µM, was analyzed through the parameters of motility, mortality, and cell viability of the worms at intervals of 3-24h. Mice were infected with cercariae and treated by gavage with SA (5mg/kg/day, in a single dose or two doses of 2.5mg/kg every 12h for 5 consecutive days) on the 1st (skin schistosomula), 14th (pulmonary schistosomula), 28th (young worms), and 45th (adult worms) days after infection. In vitro and in vivo praziquantel was the control. In vitro, SA showed schistosomicidal activity against schistosomula, young worms, and couples; with total mortality and reduced cell viability at low concentrations and incubation time. In a single dose of 5mg/kg/day, SA reduces the total worm load by 47.6%, 54%, 55.2%, and 27.1%, and female worms at 52.0%, 39.1%, 52.7%, and 20.2%, respectively, results which are similar to the 2.5mg/kg/day dose. SA reduced the load of eggs in the liver, and in histopathological and histomorphometric analyses, there was a reduction in the number and volume of hepatic granulomas, which exhibited less inflammatory infiltrate. SA has promising in vitro and in vivo schistosomicidal activity against different developmental stages of S. mansoni, in addition to reducing granulomatous liver lesions. Furthermore, in silico, SA showed good predictive pharmacokinetic ADMET profiles.

Combinations of the azaquinazoline anti-Wolbachia agent, AWZ1066S, with benzimidazole anthelmintics synergise to mediate sub-seven-day sterilising and curative efficacies in experimental models of filariasis.

Lymphatic filariasis and onchocerciasis are two major neglected tropical diseases that are responsible for causing severe disability in 50 million people worldwide, whilst veterinary filariasis (heartworm) is a potentially lethal parasitic infection of companion animals. There is an urgent need for safe, short-course curative (macrofilaricidal) drugs to eliminate these debilitating parasite infections. We investigated combination treatments of the novel anti-Wolbachia azaquinazoline small molecule, AWZ1066S, with benzimidazole drugs (albendazole or oxfendazole) in up to four different rodent filariasis infection models: Brugia malayi-CB.17 SCID mice, B. malayi-Mongolian gerbils, B. pahangi-Mongolian gerbils, and Litomosoides sigmodontis-Mongolian gerbils. Combination treatments synergised to elicit threshold (>90%) Wolbachia depletion from female worms in 5 days of treatment, using 2-fold lower dose-exposures of AWZ1066S than monotherapy. Short-course lowered dose AWZ1066S-albendazole combination treatments also delivered partial adulticidal activities and/or long-lasting inhibition of embryogenesis, resulting in complete transmission blockade in B. pahangi and L. sigmodontis gerbil models. We determined that short-course AWZ1066S-albendazole co-treatment significantly augmented the depletion of Wolbachia populations within both germline and hypodermal tissues of B. malayi female worms and in hypodermal tissues in male worms, indicating that anti-Wolbachia synergy is not limited to targeting female embryonic tissues. Our data provides pre-clinical proof-of-concept that sub-seven-day combinations of rapid-acting novel anti-Wolbachia agents with benzimidazole anthelmintics are a promising curative and transmission-blocking drug treatment strategy for filarial diseases of medical and veterinary importance.

Development of adult Dirofilaria immitis worms in the Rag2/Il-2rγ-/- mouse model

Dirofilaria immitis is the causative agent for one of the major parasitic infections in dogs. It is currently not possible to reliably diagnose the infection before the development of fertile adult female worms and the presence of microfilariae which takes six to 7 months. However, at this point adult worms already reside in the pulmonary arteries and can cause significant damage. Novel in vivo models may facilitate the development of new diagnostic tools and improve treatment options for both the early and late stages of D. immitis infections. In this paper, we aimed to increase the capabilities of recently published mouse models in which severely immune-deficient mice were shown to be susceptible to D. immitis. Our data shows that D. immitis may grow into fully developed mature male and female worms in C57BL/6 Rag2/Il-2rγ-/- mice with comparable growth rates to the natural canine host. The adult worms of D. immitis were shown to migrate into body cavities as well as the heart in this model. However, the presence of adult worms inside the heart of infected mice led to the development of caval syndrome in 36% of infected mice after five to 6 months. Overall, the current study complements recently published efforts to establish a D. immitis mouse model by extending the development of D. immitis into mature adult stages and will facilitate further preclinical research.

Rare Case of Orbital Granuloma Caused by Coexisting Male and Female Dirofilaria repens Worms: Implications for Human Host Status

Rare Case of Orbital Granuloma Caused by Coexisting Male and Female Dirofilaria repens Worms: Implications for Human Host Status