Human density, economic level and frequency of canine helminths in Buenos Aires.

The aim of this study was to explore through cross-sectional study the variation in the prevalence of parasitic helminths in canine faeces collected from green spaces of Buenos Aires according to the human density (HD) and economic level (EL) in the surroundings. HD and EL were considered as independent variables with three categories each. Twenty public squares (one hectare of surface) were randomly selected for each existing combination of the two independent variables. Ten random samples of fresh canine faeces were obtained in each square and analysed for helminths by the sedimentation and flotation techniques. The prevalence for each of the species was analysed using generalized linear models (GLM). The prevalence was modelled with a binomial error distribution and a logit link function. Helminth eggs were detected in 45 out of the 200 (22.5%) faecal samples collected and in 18 of the 20 green spaces sampled. The species observed were Ancylostoma caninum (13% of samples), Trichuris vulpis (8%) and Toxocara canis (4.5%). The GLM indicated that the prevalence of A. caninum in the slum areas (very high HD and very low EL) was higher than that in the other areas studied. However, the HD seemed to contribute more than the EL to the variations in the prevalence of A. caninum in faecal samples. The GLM showed no differences in the prevalence of the other parasite species for the different levels of the independent variables.

Development of a low-cost copro-LAMP assay for simultaneous copro-detection of Toxocara canis and Toxocara cati.

Toxocariasis is a zoonotic disease caused mainly by Toxocara canis and Toxocara cati and diagnosis in dogs and cats is an important tool for its control. For this reason, a new coprological loop-mediated isothermal amplification (LAMP) assay was developed for the simultaneous detection of these species. The primer set was designed on a region of the mitochondrial cox-1 gene. Amplification conditions were evaluated using a temperature gradient (52°C to 68°C), different incubation times (15­120 min), and different concentrations of malachite green dye (0.004­0.4% w/v). The analytical sensitivity was evaluated with serial dilutions of genomic DNA from T. canis and T. cati adult worms, and with serial dilutions of DNA extracted from feces using a low-cost in-house method. The specificity was evaluated using genomic DNA from Canis lupus familiaris, Felis catus, Escherichia coli, Toxascaris leonina, Ancylostoma caninum, Echinococcus granulosus sensu stricto and Taenia hydatigena. The LAMP assay applied to environmental fecal samples from an endemic area showed an analytical sensitivity of 10­100 fg of genomic DNA and 10−5 serial dilutions of DNA extracted from feces using the low-cost in-house method; with a specificity of 100%. Additionally, the total development of the assay was carried out in a basic laboratory and per-reaction reagent cost decreased by ~80%. This new, low-cost tool can help identify the most common agents of toxocariasis in endemic areas in order to manage prevention strategies without having to rely on a laboratory with sophisticated equipment.

Detection of parasites in canine feces at three off-leash dog parks in Portland, Oregon 2014.

Gastrointestinal parasitism is common in dogs attending parks, with variable prevalences of parasites based on geographical region and demographic factors. In this study, canine fecal samples were opportunistically collected from three off-leash dog parks in Portland, Oregon and analyzed for parasites. While some similarities with previous research was seen, much higher rates of Giardia (25.6%) and Toxocara canis (8.67%) were identified in this study. Additional findings of unexpected parasites and those with zoonotic potential make these results significant.

Dog importation and changes in canine intestinal nematode prevalence in Colorado, USA, 2013-2017.

BACKGROUND: Animal rescue and animal welfare organizations are relocating thousands of dogs per year following natural disasters and in attempts to provide greater adoption opportunities. Many dogs are sourced from the southeastern USA, which historically has a high prevalence rate for many parasites and parasitic diseases. The Colorado Department of Agriculture Pet Animal Care Facilities Act (PACFA) requires animal shelters and animal welfare organizations to report annually a variety of statistics including the numbers of dogs imported into Colorado from out of state. The Companion Animal Parasite Council (CAPC) provides data nationally, down to the state and county level, on a variety of common parasitic and vector borne diseases. These data make it possible to track changes in parasite prevalence over several years. METHODS: Test results for canine roundworm, hookworm and whipworm were collected from the CAPC maps for 2013-2017. Dog importation data for 2014-2017 was collected from PACFA reports. For evaluation of the statistical significance of prevalence changes when comparing 2013 to 2017, 2 × 2 contingency tables were constructed with both positive and negative test results for each year and the data assessed using Chi-square tests to determine if the 2017 prevalence was significantly different than the 2013 prevalence for roundworm, hookworm and whipworm. RESULTS: Significant increases in intestinal nematode prevalence occurred in Colorado from 2013 to 2017. The prevalence of canine roundworm rose 35.60%, the prevalence of canine hookworm rose 137.33% and the prevalence of canine whipworm rose 63.68%. From 2014 to 2017, over 114,000 dogs were transported into Colorado from out-of-state, by more than 130 animal shelters and rescue organizations. Three of the larger organizations reported that the majority of their dogs were obtained from New Mexico, Texas and Oklahoma. Texas and Oklahoma have historically much higher parasite prevalence than Colorado. CONCLUSIONS: Veterinarians in areas with historically low parasite prevalence where dogs from high parasite prevalence areas are arriving for adoption may need to reevaluate their recommendations regarding fecal examination and deworming frequencies as historic levels of intestinal parasite infection may no longer be accurate assessments of future infection risks.

Quantification of Toxocara canis DNA by qPCR in mice inoculated with different infective doses.

The nematode Toxocara canis is of public health importance and is the main causative agent of toxocariasis in humans. This disease is difficult to diagnose due to several factors, including the possibility of cross-reactions with other nematodes in the ELISA. To overcome this problem, molecular tests have been recommended as an alternative to identify the parasite. The quantitative real-time polymerase chain reaction (qPCR) technique was used in this study to identify and quantify the parasite load of T. canis in the mouse brain. To this end, 24 mice were divided into six groups, five of which were challenged with different infective doses of T. canis larvae (L3) (1000, 500, 250, 100 and 50 larvae), while the sixth group, uninfected, acted as negative control. Forty-five days after infection, the animals were euthanized to collect the brain, from which two portions of 20 mg of tissue were taken for DNA extraction, while the rest of the brain tissue was digested to quantify the number of larvae by microscopy. The number of DNA copies was calculated from the standard DNA quantification curve, showing values of E = 93.4%, R2 = 0.9655 and Y = -3.415. A strong positive correlation (R = 0, 81; p < .001) was found between the number of copies and the recovery of larvae from brain. However, the parasite's DNA was also identified even in animals from whose brain no larvae were recovered after tissue digestion. The results of this study therefore confirm that the qPCR technique can be a valuable tool for the detection and quantification of T. canis DNA in murine hosts, even in animals whose with tissues contain very few parasites.

Presence of Toxocara spp. and Other Zoonotic parasites Ova in Children's Playground in Karaman, Turkey

Objective: Human toxocariosis (HT) is a widespread and neglected parasitic disease around the world and it is caused by Toxocara canis and Toxocara cati, a common nematode found in dogs and cats. Childiren are caught to HT after ingestion of embriyonated Toxocara spp. eggs via contaminated materials such as soil, hair and etc. The aim of this study is to investigate Toxocara spp. and other zoonotic parasites in children's playgrounds in Karaman province of Turkey. Methods: In total, 103 samples (68 sand soil, 26 soil and 9 stool) from 20 randomly selected children's playgrounds in May 2018 in Karaman province, were investigated. Samples were examined by flotation in saturated NaCl solution and parasite ova were diagnosed under the light microscope morphologically. Results: Of the 20 screened playgorunds, 11 [55%, confidence interval (CI=33.6-75.2)]and 27 analyzed sample (26.2%, CI=18.4-35.2) were positive one or more parasite species. While Toxocara spp. eggs were the most common species in total (19.4%, CI=12.6-27.8), taeniid (Taenia spp., Echinococcus spp.) eggs and Ancylostoma spp. eggs were found in seven (6.8%, CI=2.97-12.7) and one (0.97%, CI=0.05-4.21) samples respectively. Also, one soil sample was found to be contaminated with both Toxocara and taeniid eggs. Conclusion: These results demonstrate that children's playgrounds in Karaman may be a source for HT and other zoonotic infections. We advise to be fenced children's playgrounds in order to prevent pet animal's accessibility.

Prevalence of Toxocara and Toxascaris infection among human and animals in Iran with meta-analysis approach.

BACKGROUND: Toxocariasis is a worldwide zoonotic parasitic disease caused by species of Toxocara and Toxascaris, common in dogs and cats. Herein, a meta-analysis was contrived to assess the prevalence of Toxocara/Toxascaris in carnivore and human hosts in different regions of Iran from April 1969 to June 2019. METHODS: The available online articles of English (PubMed, Science Direct, Scopus, and Ovid) and Persian (SID, Iran Medex, Magiran, and Iran Doc) databases and also the articles that presented in held parasitology congresses of Iran were involved. RESULTS: The weighted prevalence of Toxocara/Toxascaris in dogs (Canis familiaris) and cats (Felis catus) was 24.2% (95% CI: 18.0-31.0%) and 32.6% (95% CI: 22.6-43.4%), respectively. Also, pooled prevalence in jackal (Canis aureus) and red fox (Vulpes vulpes) was 23.3% (95% CI: 7.7-43.2%) and 69.4% (95% CI: 60.3-77.8%), correspondingly. Weighted mean prevalence of human cases with overall 28 records was 9.3% (95% CI: 6.3-13.1%). The weighted prevalence of Toxocara canis, Toxocara cati, and Toxascaris leonina was represented as 13.8% (95% CI: 9.8-18.3%), 28.5% (95% CI: 20-37.7%) and 14.3% (95% CI: 8.1-22.0%), respectively. CONCLUSION: Our meta-analysis results illustrate a considerable prevalence rate of Toxocara/Toxascaris, particularly in cats and dogs of northern parts of Iran. The presence of suitable animal hosts, optimum climate and close contact of humans and animals would have been the reason for higher seroprevalence rates of human cases in our region. Given the significance clinical outcomes of human Toxocara/Toxascaris, necessary measures should be taken.

Multiple Granulomas of Ocular Toxocariasis in an Immunocompetent Male.

A 25-year-old male presented with unilateral panuveitis with multiple voluminous elevated retinal lesions along with subretinal fluid and exudation. An extensive laboratory work-up was done, and a clinical suspicion of viral retinitis was considered. The patient was initiated on antiviral therapy and, subsequently, oral corticosteroids. As the corticosteroids were tapered, the patient developed worsening lesions and vitreous inflammation. Pars plana vitrectomy (diagnostic and therapeutic) was performed and cytology sample revealed a highly eosinophilic infiltrate suggestive of parasitic infection. The real-time polymerase chain reaction was positive for Toxocara cati. The diagnosis of ocular toxocariasis was made. This case highlights a highly unusual presentation where multiple retinal granulomas of ocular toxocariasis were observed in an immunocompetent male.

Canine gastrointestinal nematode transmission potential in municipal dog parks in the southeast United States.

Monthly canine parasite prophylactic products prevent not only adult heartworm infection, but also patent infections with specific gastrointestinal parasites. While most monthly products control and treat certain hookworm and roundworm infections, fewer are labeled for whipworm (Trichuris vulpis). Therefore, we hypothesized that fecal samples collected from municipal dog parks will have a greater prevalence of whipworm eggs compared to hookworm and roundworm eggs. In this study, canine fecal samples were collected from municipal dog parks in three southeastern states, with up to 20 fecal samples were collected from each park. A total of 200 fecal samples were obtained from dog parks in Georgia, North Carolina, and South Carolina. All fecal samples were examined for the presence of gastrointestinal helminths by a simple centrifugal flotation using sheather's sugar flotation solution. Of the 200 samples collected, 27% were positive for gastrointestinal helminths by fecal flotation. Of these infected fecal samples, 8.5%, 17%, and 1.5% contained whipworm, hookworm, and roundworm, respectively. However, the majority of hookworm-positive samples were collected from one park, whereas whipworm and roundworm samples were collected from multiple parks. These results could indicate that dogs are at risk of infection by all three parasites at dog parks, and that preventive strategies may need to be tailored not only to the specific region, but to specific infected dog parks.

Gastrointestinal parasites of arctic foxes (Vulpes lagopus) and sibling voles (Microtus levis) in Spitsbergen, Svalbard.

The arctic fox (Vulpes lagopus), an apex predator with an omnipresent distribution in the Arctic, is a potential source of intestinal parasites that may endanger people and pet animals such as dogs, thus posing a health risk. Non-invasive methods, such as coprology, are often the only option when studying wildlife parasitic fauna. However, the detection and identification of parasites are significantly enhanced when used in combination with methods of molecular biology. Using both approaches, we identified unicellular and multicellular parasites in faeces of arctic foxes and carcasses of sibling voles (Microtus levis) in Svalbard, where molecular methods are used for the first time. Six new species were detected in the arctic fox in Svalbard, Eucoleus aerophilus, Uncinaria stenocephala, Toxocara canis, Trichuris vulpis, Eimeria spp., and Enterocytozoon bieneusi, the latter never found in the arctic fox species before. In addition, only one parasite was found in the sibling vole in Svalbard, the Cryptosporidium alticolis, which has never been detected in Svalbard before.

Visceral larva migrans detection using PCR-RFLP in BALB/c mice infected with Toxocara canis.

Toxocara canis is an important zoonotic roundworm distributed worldwide. The infective larvae of T. canis are one of the causes of visceral larva migrans (VLM), a clinical syndrome in humans. Diagnosing VLM is difficult, and the differential diagnosis of the larval development stage is limited. Therefore, this experimental research aimed to diagnose T. canis larvae using a molecular method, not only in liver tissue, which is the most commonly affected tissue, but also in the limb muscles, lungs and brain tissues. For this purpose, 24 BALB/c mice were infected with 1000 embryonated T. canis eggs. Necropsies were performed on the second, fourth, seventh and 14th days post-infection. While a part of the samples were digested with pepsin-HCl, the molecular method was used for the remainder of the samples to replicate the mitochondrial DNA adenosine triphosphate (ATP) synthase subunit-6 gene region of T. canis. BbsI, a restriction endonuclease, was used to determine the specificity of the amplicons obtained from Polymerase chain reaction (PCR). The detection limit for embryonated eggs was recorded. The PCR results showed that the sensitivity of the PCR analysis was 83.3% in the liver (with 88.8% accuracy), 87.5% in the lungs (with 91.6% accuracy) and 75.0% in the brain, forelimb and hindlimb muscles (with 83.3% accuracy). In all tissues, the test specificity was determined to be 100%. In this study, the molecular method was applied to only experimentally infected BALB/c mice tissues; thus, it is suggested that it can be also employed in different paratenic hosts and materials possibly infected with T. canis.

Toxocara canis Larval Migration Causing Verminous Pneumonia in Fading Puppies From 2 Scottish Terrier Litters.

Migration of vertically transmitted Toxocara canis larvae through the liver and lungs is poorly documented as a cause of periparturient mortality in puppies. This case series describes 4 cases of fading puppies in 2 litters from 2 different bitches owned by the same breeder. Of the 4 cases, 4 had verminous pneumonia, 2 had fibrinoid necrosis of pulmonary arterioles, 4 had hepatic necrosis and inflammation, 2 had hepatic thrombophlebitis, and 1 had tracheal occlusion. These lesions were associated with migrating nematode larvae morphologically consistent with T. canis. The identity of the larvae was confirmed by sequencing of a portion of the ITS-2 region of nuclear ribosomal DNA. The tissues involved are consistent with the known migration pathways of this parasite. The dam of the first litter was negative for Toxocara spp. and other intestinal parasites by fecal floatation. This report highlights the need to consider T. canis migration in the differential diagnosis of fading puppies.

Ocular toxocariasis: atypical clinical course.

A 17-year-old man presented to the emergency department with complaints of retro-orbital pain of the left eye and an altitudinal visual field defect for 2 weeks. Fundus examination revealed ipsilateral hyperaemic optic disc oedema, and the patient was admitted with the presumptive diagnosis of left optic neuritis. Subsequently, during follow-up, the patient developed a retinal granulomatous lesion in the superior temporal arcade with vitritis and fibrotic strands extending to the mid-periphery. Serum antibodies detection by ELISA and aqueous humour immunoblot were positive for Toxocara canis Medical therapy with albendazole and oral steroids was instituted with satisfactory results. One year later, a new macular lesion developed with consequent vision loss.

Human toxocariasis seroprevalence among patients with uveitis in Alborz Province, Iran.

INTRODUCTION AND OBJECTIVE: Toxocariasis, predominantly caused by Toxocara canis, is a common zoonotic parasitosis worldwide. Toxocara infection is a cause of vision impairment and blindness. The presented study investigates the frequency of antibodies against Toxocara among uveitis patients and the epidemiological factors associated with disease. MATERIAL AND METHODS: Fifty-four patients with uveitis and 59 healthy subjects were studied. Anti-Toxocara antibodies status was determined in all serum samples using enzyme linked immunosorbent assay (ELISA), and seropositive samples analyzed by Western blot (WB) technique. RESULTS: The frequency of Toxocara canis infection was found to be significantly higher in uveitis patients, compared to healthy controls by the use of ELISA test, being 14.8% and 1.7%, respectively. From 8 seropositive samples, 5 (62.5%) patients exhibited Toxocara immunoglobulin G (IgG) antibodies in response to Western blot, whereas in the control group, none were detected positive by Western blot. No significant difference was found between pet owners, nor between different places of residence. The seroprevalence to Toxocara among uveitis patients was significantly related to gender, age and medical diagnosis. The highest prevalence was found in patients with posterior uveitis (27.8%). CONCLUSIONS: Anti-Toxocara antibody titers are associated with the risk of vision impairment -uveitis. The risk factor associated with Toxocara exposure identified in this study warrants further investigation.

Ultrasonography for early diagnosis of Toxocara canis infection in puppies.

Toxocara canis is one of the most common intestinal parasites in dogs and represents a highly infectious zoonotic parasite worldwide. Adult worms live in the bowel of dogs, and infections in puppies are commonly acquired transplacentally. The biology of the parasite and the commonly used diagnostic method, based on faecal examination, often prevent an early diagnosis of toxocariasis in puppies. Ultrasonographic diagnosis of intestinal ascariasis could be a feasible alternative method to diagnose T. canis infection in puppies during the prepatent period. The present study evaluated the diagnostic accuracy of ultrasonography for the diagnosis of intestinal toxocariasis in new-born puppies during the prepatent period. Fifty-four new-born puppies were prospectively recruited in the study. Each dog underwent intestinal ultrasonography and copro-microscopic examination every 5 days, starting from the 10th day post-birth. Intestinal ultrasonography visualized adult T. canis nematodes in the puppies' small intestine from the 10th day post-birth. On the 15th day after birth, ultrasonography showed 100% specificity and 85.4% sensitivity in diagnosing T. canis infection, despite negative results deriving from the copro-microscopic examination performed at the same time point. Our results showed that ultrasonography can be used as test for early diagnosis of T. canis infection in new-born puppies during the prepatent period. Early ultrasonographic diagnosis of T. canis infection in puppies could help control the disease in dogs and reduce the zoonotic risk for the human population.

Diagnostic Potential of Anti-RTE30 Polyclonal Antibodies In A Blocking Elisa For Toxocara canis Detection.

The main etiologic agent of human toxocariasis, a zoonotic disease, is the helminth Toxocara canis. Among the diagnostics used for human toxocariasis, ELISA using T. canis excretion and secretion antigen (TES) is considered as a standard technique. TES antigen requires the cultivation of T. canis larvae, which makes its production difficult. Besides this, the use of TES antigen does not eliminate the cross-reactions with other similar proteins that are produced by other intestinal worms. In this context, recombinant antigens are being tested to improve the diagnosis of human toxocariasis. Herein, we describe the production of polyclonal antibodies against recombinant protein TES30 (pAb-rTES30) and evaluate its use in a blocking ELISA (b-ELISA) using human sera. The b-ELISA showed 95.6% sensitivity and 94.4% specificity. Thus, the b-ELISA using pAb-rTES30 offers a viable option for toxocariasis diagnosis owing to its configuration, which prevents cross-reactivity with non-species-specific antibodies.