Aspects of Toxocara epidemiology: toxocarosis in dogs and cats

Extracellular traps development in canine neutrophils induced by infective stage Toxocara canis larvae

Neutrophils, a crucial element of the host defense system, develop extracellular traps against helminth parasites. Neutrophils accumulate around the larvae of Toxocara canis (T. canis) in the tissues of the organism. This study aimed to determine the reaction in canine neutrophils after incubation with infective stage T. canis larvae (L3) in vitro. Most L3 were still active and moved between the extracellular traps (NETs) after 60-min incubation. NETs were not disintegrated by L3 movement. The L3 was only immobilized by NETs, entrapped larvae were still motile between the traps at the 24 h incubation. NETs were observed not only to accumulate around the mouth, excretory pole or anus but also the entire body of live L3. The extracellular DNA amount released from the canine neutrophils after being induced with phorbol 12-myristate 13-acetate was not affected by T. canis excretory/secretory products obtained from 250 L3. To the Authors'knowledge, the extracellular trap structures was firstly observed in canine neutrophils against T. canis L3 in vitro. NETs decorated with myeloperoxidase, neutrophil elastase and histone (H3) were observed under fluorescence microscope. There were not significant differences in the amount of extracellular DNA (P > 0.05), but the morphological structure of NETs was different in the live and head-inactivated T. canis larvae.

Microscopic and molecular prevalence and associated risk factors with Toxocara and Blastocystis infection in dogs and cats in Mitidja, Algeria

Domestic dogs and cats can serve as a source of environmental contamination with Toxocara spp. and Blastocystis spp., and this represents a neglected public and veterinary health problem. We assessed the microscopic and molecular prevalence of these species in a locality in Algeria and identified the associated risk factors. The faeces of 225 dogs and 78 cats were collected in Mitidja between March and July 2022. The samples were analysed by coproscopy and by polymerase chain reaction (PCR) targeting the Internal Transcribed Spacer 2 (ITS2) and Small Subunit Ribosomal (SSU-RNA) of T. canis and Blastocystis spp. respectively. The overall microscopic prevalence of Toxocara spp. in dogs and cats was 9.78 ± 1.98% and 12.82 ± 7.42%, respectively. The rate of Blastocystis spp. was 15.11 ± 2.39% and 15.38 ± 4.08% in dogs and cats, respectively while the molecular prevalence of T. canis in dogs was 4.89 ± 1.44% and in cats 1.28 ± 1.27%; the prevalence of Blastocystis spp. was 41.78 ± 3.29% and 34.62 ± 5.39% in dogs and cats, respectively. Phylogenetic and phylogeographic analyses identified the presence of the H1 subtype of T. canis in dogs, and the ST1 subtype of Blastocystis in dogs and cats. Dogs with clinical signs were more likely to be infected with T. canis (OR 6.039, P < 0.05) than healthy dogs. This study demonstrates that dogs and cats are carriers of Toxocara spp. and Blastocystis spp. and are therefore a source of environmental contamination. Veterinarians and human health professionals should work together to implement control strategies as part of a "One Health" approach to improving animal health and reducing the risk of transmission to humans.

Understanding the research and practical needs required to control toxocariasis in Iran

Human toxocariasis (HT) is a widespread zoonotic infection globally, notably prevalent in tropical areas. Enhancing our understanding of toxocariasis can lead to increased attention towards the socioeconomic impact and control of this neglected zoonosis. We conducted a comprehensive review of all available articles and official documents on toxocariasis in Iran to identify research gaps and critical needs for its control. This review highlights that despite numerous studies exploring various aspects of toxocariasis in definitive and paratenic hosts, as well as humans and environmental contamination, significant data deficiencies and gaps persist across different regions in the country. These gaps involve investigating the worm burden and reinfection rates in definitive hosts, developing more sensitive methods to detect and differentiate of Toxocara species, and understanding the behavior of definitive host animals. Additionally, identifying potential paratenic hosts for HT and exploring the organ-specific affinity and survival duration of Toxocara larvae within these hosts are essential areas for exploration. It's also imperative to comprehend the sylvatic and domestic cycles of the parasite in paratenic hosts. Furthermore, assessing egg density in the environment, exploring potential new sources such as water, and identifying regions with optimal climatic conditions for the survival and development of Toxocara eggs are crucial for the formulation of effective prevention and control strategies. Identifying at-risk groups, developing early diagnosis techniques, employing imaging methods, and identifying long-term complications in humans are also crucial. Community health organizations should prioritize health education for the public and professionals. Furthermore, accurately estimating definitive host populations, monitoring and preventing their movements in public places, implementing regular deworming practices for pets and stray hosts, and recognizing the infection's significance as a health priority are critical. This comprehensive understanding advocates for a holistic "one health" approach to control of HT.

Toxascaris leonina infected domestic cat (Felis catus) in Egypt; PCR-based molecular characterization of nematode eggs: a potential hazards to human health

This molecular-epidemiological study was conducted in several locations in Cairo and Giza Governorates in domestic cats (Felis catus) to detect the most common intestinal helminths in feces and molecularly characterize this nematode. So, three hundred domestic cats were admitted to different clinics around Cairo and Giza Governorates with severe diarrhea, even watery, between January 2023 and April 2023. The ages of the cats ranged from 1 to 2.5 years old. Blood, sera, and urine samples were collected for further investigation of the health condition of the animals. Toxascaris leonina was the major intestinal parasite found in cat stools, with a prevalence rate of 5% (15 cats). Toxascaris leonina (T. leonina) eggs had oval elliptical surfaces and thick cuticles. An embryo was located inside the smooth outer shell wall of the shell. The animals suffer from normocytic normochromic anemia with leukocytosis, relative lymphocytosis, and thrombocytopenia. The amplification of the ITS-rDNA region from the ascaridoid nematodes was successfully performed using NC5 and NC2 primers. The PCR product of the ITS-rDNA fragment was sequenced and yielded 860 bp. The accession number of the sequenced ITS-rDNA region was OQ735413, submitted to Gene Bank, and based on the blast analysis of NCBI, the current ascaridoid nematode proved to be genetically related to the family Ascarididae and identified as T. leonina.

Repertoire of P-glycoprotein drug transporters in the zoonotic nematode Toxocara canis

Toxocara canis has a complex lifecycle including larval stages in the somatic tissue of dogs that tolerate macrocyclic lactones. In this study, we investigated T. canis permeability glycoproteins (P-gps, ABCB1) with a putative role in drug tolerance. Motility experiments demonstrated that while ivermectin failed to abrogate larval movement, the combination of ivermectin and the P-gp inhibitor verapamil induced larval paralysis. Whole organism assays revealed functional P-gp activity in larvae which were capable of effluxing the P-gp substrate Hoechst 33342 (H33342). Further investigation of H33342 efflux demonstrated a unique rank order of potency for known mammalian P-gp inhibitors, suggesting that one or more of the T. canis transporters has nematode-specific pharmacological properties. Analysis of the T. canis draft genome resulted in the identification of 13 annotated P-gp genes, enabling revision of predicted gene names and identification of putative paralogs. Quantitative PCR was used to measure P-gp mRNA expression in adult worms, hatched larvae, and somatic larvae. At least 10 of the predicted genes were expressed in adults and hatched larvae, and at least 8 were expressed in somatic larvae. However, treatment of larvae with macrocyclic lactones failed to significantly increase P-gp expression as measured by qPCR. Further studies are needed to understand the role of individual P-gps with possible contributions to macrocyclic lactone tolerance in T. canis.

Zoonotic parasites associated with predation by dogs and cats

One of the most common behaviors of cats that have an indoor/outdoor lifestyle is to bring hunted "gifts" to their owners, represented by small mammals, reptiles and birds. Access to the outdoors by dogs and cats may represent a problematic issue, since they may be at risk of diseases, traffic accidents and ingestion of toxins. Yet, the impact of this population of roaming dogs and cats predating wildlife is another concerning issue that receives less attention. Despite these risks, most owners still prefer to give outdoor access to their pets to allow them to express their "natural instincts," such as hunting. Therefore, with a growing population of > 470 million dogs and 373 million cats worldwide, predation not only represents a threat to wildlife, but also a door of transmission for parasitic diseases, some of them of zoonotic concern. In this review, the role played by dogs, and especially cats, in the perpetuation of the biological life cycle of zoonotic parasites through the predation of rodents, reptiles and birds is discussed. Feral and domestics dogs and cats have contributed to the population collapse or extinction of > 63 species of reptiles, mammals and birds. Although the ecological impact of predation on wild populations is well documented, the zoonotic risk of transmission of parasitic diseases has not received significant attention. The parasitic diseases associated to predation vary from protozoan agents, such as toxoplasmosis, to cestodes like sparganosis and even nematodes such as toxocariasis. Raising awareness about predation as a risk of zoonotic parasitic infections in dogs and cats will aid to create responsible ownership and proper actions for controlling feral and free-roaming cat and dog populations worldwide.

Grassland versus forest dwelling rodents as indicators of environmental contamination with the zoonotic nematode Toxocara spp

Small mammals are suspected of contributing to the dissemination of Toxocara canis and helping with the parasite survival during periods when there is a temporary absence of suitable definitive hosts. While the primary aim of the current study was the assessment of seroprevalence of Toxocara spp. infections in wild rodents in Poland, we also explored the role of intrinsic (sex, age) and extrinsic factors (study site) influencing dynamics of this infection to ascertain whether grassland versus forest rodents play a greater role as indicators of environmental contamination with T. canis. We trapped 577 rodents belonging to four species (Myodes glareolus, Microtus arvalis, Microtus agrestis, Alexandromys oeconomus) in north-eastern Poland. Blood was collected during the parasitological examination, and serum was frozen at - 80 °C until further analyses. A bespoke enzyme-linked immunosorbent assay was used to detect antibodies against Toxocara spp. We found Toxocara spp. antibodies in the sera of all four rodent species with an overall seroprevalence of 2.8% [1.9-4.1%]. There was a significant difference in seroprevalence between vole species, with the grassland species (M. arvalis, M. agrestis and A. oeconomus) showing a 16-fold higher seroprevalence (15.7% [8.7-25.9%]) than the forest-dwelling M. glareolus (0.98% [0.5-1.8%]). We hypothesise that the seroprevalence of Toxocara spp. differs between forest and grassland rodents because of the higher contamination of grasslands by domestic dogs and wild canids. Our results underline the need for wide biomonitoring of both types of ecosystems to assess the role of rodents as indicators of environmental contamination with zoonotic pathogens.

WormWatch: Park soil surveillance reveals extensive Toxocara contamination across the UK and Ireland

BACKGROUND

Toxocarosis is a globally distributed zoonotic disease, but sources of infection are not well documented over large geographical scales. To determine levels of environmental contamination, soil from 142 parks and recreational areas across the UK and Ireland was assessed for the presence of Toxocara.

METHODS

Toxocara ova (eggs) were isolated from soil samples by sieving and flotation and then enumerated. Individual eggs were isolated and imaged, and a subset was characterised by species-specific PCR and Sanger sequencing.

RESULTS

Characteristic Toxocara-type eggs were found in 86.6% of parks, with an average of 2.1 eggs per 50 g of topsoil. Representative eggs were confirmed as Toxocara canis by Sanger sequencing, with many eggs containing developed larvae, hence being viable and potentially infective. Positive samples were more common, and egg density was higher, in parks with greater perceived levels of dog fouling.

LIMITATIONS

Samples were collected at a single timepoint and with limited spatial mapping within parks. Further study is needed to discern spatiotemporal differences within parks and recreational areas.

CONCLUSION

Toxocara is widespread in soil in public parks, indicating a need for further efforts to reduce egg shedding from pet dogs. Standardised methods and large-scale surveys are required to evaluate risk factors for egg presence and the impact of interventions.

Retrospective Survey of Dog and Cat Endoparasites in Ireland: Antigen Detection

Endoparasites of dogs and cats, play an important role in both veterinary medicine and public health. Untreated and stray dogs and cats, in particular, play an important role in contaminating the environment with important zoonotic parasites. Thus, the aim of this study was to estimate the prevalence of intestinal parasites in stray dogs and cats using highly sensitive and specific copro-antigen tests. Archive faecal samples from previous surveys conducted between 2016−2019 from dogs (n = 789) and cats (n = 241) were included in this study. The IDEXX Fecal Dx™ antigen panel was used for the detection of Toxocara, hookworms, Trichuris and the SNAP™ Giardia antigen assay was used for the detection of Giardia infection. Giardia duodenalis was the most common parasite (26%, n = 205) detected in the dogs, followed by ascarids (17.6%, n = 139) and hookworms (5.3%, n = 42). Trichuris vulpis was only detected in 1 dog. Ascarids (23.2%, n = 56) was the most common parasite detected in the cats, followed by Giardia (12.9%, n = 31) and hookworms (n = 7, 2.9%). No whipworms were detected in cats. Overall, there was little difference in the positivity between sexes in both dogs and cats. However, in terms of age, adolescent dogs (<3 years) and kittens (<1 year) had the highest parasite prevalence overall, with G. duodenalis and ascarids being the most prevalent. This study shows a high prevalence of parasite infection in untreated and stray dogs and cats in the greater Dublin area in Ireland. Since they live in synanthropic conditions and can roam over vast distances they can contaminate public areas and pose a risk to both humans and owned pets that utilise these spaces. It is therefore important to raise public awareness and increase the knowledge on zoonotic parasites.

Financial and Socio-Economic Effects of Investment in the Context of Dog Population Management

The modern world faces serious challenges associated with the presence of stray dogs on the streets, especially in urban areas. Vardar Planning Region in North Macedonia, which consists of nine municipalities, experiences such challenges. According to current reports, the number of stray dogs on the streets of cities in this region has increased, which has resulted in an increase in the number of dog attacks on residents. As the existing capacities are small in the registered shelters, we considered the possibility of building a new shelter for stray dogs to meet the needs of this region. The goal of our paper is the evaluation of the financial and socio-economic justifications for the construction of a shelter for stray dogs in the Vardar Planning Region (VPR). The results of the financial justification analysis show that the project does not provide satisfactory financial results. Namely, the Financial Net Present Value (FNPV) is negative, with a value of EUR 75,291. The Financial Internal Rate of Return (FIRR) is 0.57%, lower than the discount rate, which is not acceptable for a private investor. The Financial Benefit-Cost Ratio (FB/CR) of this project is 0.925, suggesting that the total discounted costs are greater than the total discounted revenues. On the other hand, the expected socio-economic benefits from this project are multifaceted, including savings in stray dog bite costs, savings in the cost of traffic accidents caused by stray dogs, and savings in the treatment of diseases caused by stray dogs. The results of the economic analysis show that this investment has full socio-economic justification and that it should be implemented. The Economic Net Present Value (ENPV) is positive and amounts to EUR 789,916. The Economic Internal Rate of Return (EIRR) is 25.94% and the Economic Benefit-Cost Ratio (EB/CR) amounts to 1.90, i.e., greater than 1. The results of the sensitivity analysis also confirm the justification for the realization of this project.

Gastrointestinal helminths in dogs: occurrence, risk factors, and multiple antiparasitic drug resistance

Helminth infections are detrimental to the overall health of dogs; therefore, this study aimed to identify antiparasitic-resistant helminths and evaluate the infection rate and risk factors for parasitism in canines. For this purpose, a parasitological evaluation of 38 randomly selected animals was performed, followed by the evaluation of the anthelminthic efficacy of three drugs: pyrantel pamoate with praziquantel (Canex Composto®), fenbendazole (Fenzol Pet®), and milbemycin oxime with praziquantel (Milbemax C®). Among the evaluated animals, 22/38 (57.89%) tested negative and 16/38 (42.71%) tested positive for Ancylostoma caninum infection. Evaluation of the efficacy of antiparasitic drugs showed that 12/16 (75%) dogs were infected with helminths that were susceptible to pyrantel pamoate with praziquantel. Among those for which pyrantel pamoate with praziquantel was not effective, 3/4 (75%) were susceptible to fenbendazole, while the remaining case resistant to both pyrantel pamoate with praziquantel and fenbendazole was sensitive to milbemycin oxime with praziquantel (100%). The odds ratio of infection in dogs inhabiting environments containing soil or grass was 6.67 times higher than that in dogs inhabiting impermeable environments. Mixed-breed dogs (SRD) were 6.54 times more likely to be infected compared to purebred dogs. A. caninum resistant to pyrantel pamoate with praziquantel (4/16, 25%) and fenbendazole (1/4, 25%) were detected. The results of this study demonstrated the importance of coproparasitological monitoring by professionals before and after treatments to assess antiparasitic drug effectiveness, ensure animal health and welfare, and minimize animal exposure to risk factors.

Toxocara canis Infection Alters mRNA Expression Profiles of Peripheral Blood Mononuclear Cells in Beagle Dogs at the Lung Infection Period

Simple Summary

Toxocariasis is one of the most neglected zoonoses in the world. Toxocara canis is the main pathogen causing toxocariasis in humans and animals, threatening public health. To date, the mechanism by which the larvae of T. canis escape the attack of immune cells in the blood is still poorly understood. Using RNA-seq technology, the transcriptional alterations of Beagle dog peripheral blood mononuclear cells (PBMCs) between the presence and absence of T. canis infection were analyzed during the lung infection period, and 1066 upregulated genes and 1076 downregulated genes were identified (padj < 0.05 and |log₂ (FoldChange)| > 1). In addition, many immune- or inflammation-related GO terms and KEGG signaling pathways were significantly altered during T. canis infection by GO annotation and KEGG enrichment analysis. The present study revealed that T. canis infection can alter the mRNA profiles of PBMCs in Beagle dogs during the lung infection period, which has important implications for a better understanding of the interaction mechanism between T. canis and host immune cells.

Abstract

Toxocara canis is a neglected zoonotic roundworm distributed all over the world, causing toxocariasis in humans and animals. However, so far, the immune mechanism of T. canis infection in definitive hosts remains to be clarified. In this study, the transcriptional alterations of Beagle dogs’ peripheral blood mononuclear cells (PBMCs) induced by T. canis infection during the lung infection period were analyzed using RNA-seq technology. A total of 2142 differentially expressed genes were identified, with 1066 upregulated genes and 1076 downregulated genes. Many differentially expressed genes participated in the biological process of intracellular signal transduction, as well as the immune- or inflammation-related KEGG signaling pathway, such as the Notch signaling pathway, Toll-like receptor signaling pathway, and NF-kappa B signaling pathway, through KEGG enrichment analysis. This study indicated that T. canis infection could suppress the biological function of Beagle dogs’ PMBCs and provided basic data to further clarify the interaction mechanism between T. canis and host immune cells.

High Toxocara cati prevalence in wild, free-ranging Eurasian lynx (Lynx lynx) in Finland, 1999–2015

In Finland, free-ranging Eurasian lynx (Lynx lynx) population has grown from 30 to 40 individuals to 2800 individuals since the species became partly protected in 1962. Changes in host population size are known to have an impact on host-parasite dynamics, and the Eurasian lynx population in Finland provides a unique opportunity for studying the potential effects of dramatic population increase and expansion of a solitary apex predator on their parasite prevalence and abundance. Toxocara cati is a zoonotic gastrointestinal parasite infecting domestic cats and wild felids worldwide. We studied T. cati infection prevalence and worm burden in 2756 Eurasian lynx individuals from Finland, covering the years 1999–2015. Toxocara cati worms that had been collected from intestinal contents were identified based on morphology. We performed regression analyses to investigate possible associations of age, sex, and host population density with T. cati infection. We found T. cati from 2324 (84.3%, 95% confidence interval 82.9–86.0) of the examined lynx. Each year, the infection prevalence was higher than 75% and not density dependent. The parasites were strongly aggregated, with older individuals harboring fewer T. cati than younger ones did. Old females aged 9–15 years had higher T. cati abundance than males of the same age group. Our results indicate that T. cati was a common and abundant parasite of Eurasian lynx throughout the study period, regardless of the changing population size and density.

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84% of 2756 Eurasian lynx (Lynx lynx) from Finland had Toxocara cati infection.

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The prevalence was high throughout 1999–2015, while lynx population size tripled.

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Old female lynx had significantly higher Toxocara cati abundance than old males.

Human Toxocariasis: 2010 to 2020 Contributions from Brazilian Researchers

This is a review of the published contributions made by Brazilian researchers between 2010 and 2020 on the natural history of human toxocariasis and the effects of human toxocariasis on nonhuman paratenic hosts.

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.

Seroprevalence, risk factors, and clinical symptoms of Toxocara spp. infection among children 3-15 years old in northern Iran

The World Health Organization has categorized toxocarosis as a neglected tropical disease despite its significant impact on high-risk groups such as children. This study aimed to investigate the seroprevalence, risk factors, and clinical symptoms of Toxocara spp. infection among children 3-15 years old in northern Iran. A total of 386 children were enrolled in the study. All serum samples were tested for the presence of IgG antibodies against Toxocara spp. infection using an enzyme-linked immunosorbent assay. Moreover, relevant risk factors and clinical symptom data were obtained using questionnaires. Data analysis was performed using the SPSS software version 24. The overall seroprevalence of Toxocara spp. infection was found 2.85 % (11/386). However, Toxocara spp. infection was high for some risk factors, including eating soil (14.3 %), contacting cats (6.7 %), and consuming raw vegetables (3.7 %). However, there were no statistically significant differences regarding the risk factors and socio-demographic characteristics. Considering the clinical symptoms, Toxocara spp. infection was different in children with eosinophilia (20 %), ocular disorders (8.3 %), skin disorders (7.7 %), liver disorders (4.5 %), and stomach ache (4.2 %), although not statistically significant. The results revealed that the seroprevalence of Toxocara spp. infection was relatively low in children in northern Iran. It is suggested to conduct more studies in different parts of Iran to gain a deeper understanding of the toxocarosis seroprevalence and its status in high-risk groups such as children with asthma, hypereosinophilic syndrome, allergic skin disorders, and epilepsy.

Toxocara cati and Other Parasitic Enteropathogens: More Commonly Found in Owned Cats with Gastrointestinal Signs Than in Clinically Healthy Ones

Intestinal parasites are involved in the health and wellbeing of cats and some of them, due to their zoonotic potential, represent a problem for public health. This study aimed to assess the prevalence of parasitic infections in cats with gastrointestinal signs. Fecal samples collected from 137 cats were analyzed by the flotation method using a sodium chloride saturated solution. The overall prevalence of intestinal parasites was 50.4%. Intestinal parasites were significantly (p < 0.0001) more common in cats with digestive clinical signs (66.7%) than in clinically healthy ones (19.2%). Toxocara cati (40.2%) was the most frequently identified intestinal parasite, followed by Cystoisospora spp. (10.2%), hookworms (3.7%), Taeniidae (2.2%), Giardia duodenalis (2.2%), and Toxoplasma gondii (0.7%). Toxocara cati (53.3%, p < 0.0001) and Cystoisospora spp. (15.6%, p < 0.001) were significantly more frequently diagnosed in cats with clinical signs. A lack of deworming in the last three months (OR: 15.9), outdoor access (OR: 13.8), the presence of digestive symptoms (OR: 5.4), and young age (OR: 4.2) were identified as risk factors for T. cati infection by logistic regression analysis. Regardless of age, gastrointestinal signs like vomiting, diarrhea, and inappetence were positively associated with T. cati.

A prospective seroepidemiological study of toxocariasis during early childhood in coastal Ecuador: potential for congenital transmission and risk factors for infection

Background

Although Toxocara spp. infection has a worldwide distribution, to our knowledge, no data from birth cohorts have been reported in published studies on the potential for congenital transmission and determinants of infection in early childhood.

Methods

We followed 290 mother-infant pairs from birth to 5 years of age through periodic collection of data and samples at birth, 7 and 13 months and 2, 3 and 5 years of age. Data on potential risk factors and confounders were collected by maternal questionnaire. Blood for plasma was collected from the mother at time of birth and periodically from the child for detection of anti-Toxocara spp. immunoglobulin G (IgG) antibodies using a Toxocara canis larval excretory-secretory antigen-based enzyme-linked immunosorbent assay. Stool samples were collected from the mother around the time of birth and periodically from the child for microscopic detection of soil-transmitted helminths (STH). Associations between potential risk factors and Toxocara spp. seroprevalence and seroconversion were estimated using multivariable logistic regression and generalized estimating equations.

Results

Toxocara spp. seroprevalence was 80.7% in mothers and in children was 0%, 9.3%, 48.4%, 64.9%, and 80.9% at 7 months, 13 months, 2, 3 and 5 years, respectively. Risk factors significantly associated with increases in seroprevalence over the first 5 years of life in multivariable analyses were age [Odds ratio (OR) 2.06, 95% confidence interval (CI) 1.39–2.27, P < 0001], male sex (female vs. male: OR 0.66, 95% CI 0.48–0.89, P = 0.006), maternal ethnicity (non-Afro vs. Afro-Ecuadorian: OR 0.65, 95% CI 0.47–0.91, P = 0.011), lower maternal educational and socioeconomic level, and childhood STH (OR 2.29, 95% CI 1.51–3.47, P < 0.001). Seroconversion rates for infection were greatest at 2 years of age (3.8%/month). Factors associated significantly with seroconversion at 2, 3 or 5 years were childhood STH infection, male sex, and more frequent domestic cat exposure.

Conclusions

Our data, from an area of high Toxocara spp. endemicity, indicate no congenital transmission but high rates of seroconversion after 13 months of age reaching maternal levels of seroprevalence by 5 years of age. Factors associated with seroprevalence and seroconversion included STH infections, domestic cats, maternal ethnicity, male sex, STH infections, and markers of greater poverty.

Role of cats in human toxocarosis

Toxocara cati, the feline ascarid, is ubiquitous in domestic cats globally and is increasingly recognised as an important zoonotic species. In the definitive host, infections with the adult ascarid usually do not present any clinical signs; if clinical signs do appear, it is usually in kittens infected with T. cati, especially by the transmammary route. Diseases may include cachexia, a pot-bellied appearance, respiratory disorders, diarrhoea, vomiting, among other signs, and these may present as early as 3 weeks of age. However, infections with Toxocara spp. larvae in paratenic hosts (including humans and many other animals), can result in serious complications from the migration of larvae. Historically, there has been an assumption that Toxocara canis was the most likely cause of Toxocara spp.-related disease; while it is probably true that T. canis is responsible for the majority of infections, it is important that those caused by T. cati are accurately identified so that the contribution of this parasite to human disease can be established and then handled appropriately. Overall, the detection of infections in cats and the control of parasite stages in the environment are essential to minimise the infection risk to other animals or humans.

Seroepidemiological Study of Toxocariasis in Children Aged 6-14 Year Old in Sanandaj, Western Iran

Background:

Toxocariasis is a disease caused by Toxocara nematodes and occurs from consuming their eggs. The main hosts of these worms are dogs and cats. The disease in humans becomes a visceral larva migrans (VLM). This descriptive cross-sectional study was conducted to determine the prevalence of toxocariasis in children aged 6–14 years.

Methods:

This cross-sectional descriptive study was conducted from Jun 1 2016 to Dec 1 2017 in Sanandaj, west of Iran. A total of 182 serum samples were collected from children age 6 to14 yr referred to medical diagnostic laboratories. Demographic data (age, sex, and parents’ literacy status), clinical signs (cough, headache, fever, abdominal pain), and the history of contact with dogs and cats was collected by a questionnaire. The presence of anti-Toxocara IgG antibody was detected by T. canis IgG ELISA (IBL, Germany) kit.

Results:

Of 182 subjects, 97 (53.3%) were male and 85 (46.7%) female. The average age was 9.2 years. Antibodies against T. canis were positive in three cases (1.65%) of all the studied subjects.

Conclusions:

The results showed a low prevalence of toxocariasis in children studied.

Coprological survey of endoparasite infections in owned dogs and owners' perceptions of endoparasite control in Belgium and the Netherlands

Infections with endoparasites are common in dogs. Some of these parasites are potentially zoonotic and therefore a public health concern. A survey was conducted in twenty-six small animal practices to evaluate the prevalence of endoparasites in Belgian and Dutch owned dogs older than 6 months as well as risk factors associated with infection. Out of 239 faecal samples screened (168 in Belgium and 71 in the Netherlands), 18 dogs were tested positive for at least one type of endoparasite with three dogs co-infected with two parasitic species. Toxocara sp. was the most frequently found endoparasite (4.6%). Three other dogs were positive for Angiostrongylus vasorum (1.4%) using the Baermann method and confirmed in one dog by the Angiodetect® test. Age and predation behaviour were identified as two risk factors associated with endoparasite infection. Although the majority (77%) of the owners in this study reported to administer at least one anthelmintic treatment per year, only a minority of them (24.3%) were aware of the risk to human health, indicating that owner awareness is sub-optimal. For dog owners, human toxocarosis and other potential zoonoses remain an underestimated health concern. The implementation of sustainable parasite control strategies should be promoted taking also into account the public health risk.

Epidemiological survey on intestinal helminths of stray dogs in Guimarães, Portugal

The new legislative framework on Animal Welfare brought increased responsibilities to municipal shelters, in particular in the collection of stray dogs, their sterilization and future adoption. These centers quickly became overcrowded, leading to high parasitism environmental contamination, to the easy spread of parasitic infections and to increased risks to public health. The prevalence of intestinal parasites was evaluated by examination of dog faecal sample, in the municipal control animal centre of Guimarães (north Portugal), identifying risk factors and transmission to man. The overall prevalence of gastrointestinal helminths was 57.2% (95% confidence interval 41.3–71.9%) and observed helminths of the gastrointestinal tract were recorded: Ancylostoma caninum (33%), Toxocara canis (29%), Dipylidium caninum (6%), Capillaria spp. (3%), Trichuris vulpis (1.66%). It is important to point out that young dogs were significantly infected more frequently (p ≤ 0.1) than non-sterilized females and the higher occurrence of nematode infection occurred at the new arrival of stray dogs, in the third collection. With impact on public health, the higher prevalence (p ≤ 0.1) of T. canis in young dogs suggests the existence of real risk for human infection and demonstrate the necessity for a parasite control programme reinforcement at the municipal dog shelter.

Prevalence of toxocariasis and its related risk factors in humans, dogs and cats in northeastern Iran: a population-based study

BACKGROUND

Toxocariasis is one of the most common zoonotic infections in dogs and cats. The objectives of this study were to determine the prevalence of anti-Toxocara antibodies and identify the epidemiological and clinical features and related risk factors of toxocariasis in the general population along with the prevalence of this infection in dogs and cats in northeast Iran.

METHODS

In this cross-sectional study, anti-Toxocara antibodies from 1150 urban and rural participants were examined using a commercial enzyme-linked immunosorbent assay. In addition, the stool specimens of 538 dogs and 236 cats were tested using the formalin-ether concentration technique. Sociodemographic data and related risk factors were collected using a structured questionnaire and the data on clinical manifestations were obtained from personal health records.

RESULTS

Anti-Toxocara antibodies were detected in 7.2% (83/1150) of the study population. Risk factors for seropositivity based on multivariable analysis were younger age (p=0.019), living in rural areas (p=0.048), occupations with high exposure risk to toxocariasis (p=0.001), contact with dogs or cats (p=0.003), contact with soil (p=0.001), history of geophagy (p=0.001) and the consumption of raw or undercooked liver (p=0.001). The prevalence of symptoms such as asthma, shortness of breath, blurred vision, abdominal pain and epilepsy were significantly higher in seropositive individuals compared with seronegative ones. Toxocara eggs were found in 15.1% (81/538) of dogs and 34.7% (82/236) of cats. A significant relationship was found between infection in dogs and cats and age, type, place of residence and anthelmintic consumption.

CONCLUSIONS

Identification of anti-Toxocara antibodies in the general population and the presence of confirmed infections in dogs and cats indicates exposure to Toxocara infection as a public health problem in northeast Iran.

Efficacy of a chlorocresol-based disinfectant product on Toxocara canis eggs

Toxocara canis is a common parasite of dogs and can cause zoonotic toxocariasis in humans. As a part of control programs for this agent, optimized hygiene including chemical disinfection is considered essential in the prevention and control of zoonotic toxocariasis in humans. However, commonly used disinfectants at present mostly fail to inhibit the embryogenesis and viability of T. canis eggs. To this effect, the present study was designed to evaluate the effect of a chlorocresol-based disinfectant product Neopredisan®135-1 (NP) on embryonic development of T. canis eggs in vitro and to investigate the infectivity of exposed eggs by assessing larval establishment in a mouse model. Under in vitro conditions, NP at a final concentration of 0.25, 0.50, 1, 2, or 4% all exhibited significant killing effect on T. canis embryogenesis compared with the control eggs (P < 0.05), regardless of contact times (30, 60, 90, or 120 min). Such killing activity increased in a concentration- and time-dependent manner, with a maximum killing efficacy of 95.81% at 4% concentration and 120 min exposure time. Comparisons between low and high concentrations and between short and long contact times concluded that a protocol using the 1% concentration of NP with a 90-min contact could be the most suitable for practical application. Additionally, the lower larval recovery in mice inoculated with eggs treated by either 0.25 or 0.5% NP than that from their corresponding controls (P < 0.05) verified once again that NP had an adverse impact on the larval development of T. canis eggs even at a low concentration. To the best of our knowledge, this is the first study to report the effect of the chlorocresol-based disinfectant NP on the embryonation and larval development of T. canis eggs, and the results presented here would contribute to environmental clearance and control of toxocariasis by providing an alternative disinfectant resource. However, it is highlighted that the clearance of the novel and existing sources of infection including larvated eggs in places treated with NP is not guaranteed and therefore continuous monitoring and additional disinfection are still required.

TroCCAP recommendations for the diagnosis, prevention and treatment of parasitic infections in dogs and cats in the tropics

The Tropical Council for Companion Animal Parasites Ltd. (TroCCAP) is a not-for-profit organisation whose mission is to independently inform, guide and make best-practice recommendations for the diagnosis, treatment and control of companion animal parasites in the tropics and sub-tropics, with the aim of protecting animal and human health. In line with this primary mission, TroCCAP recently developed guidelines for the diagnosis, treatment and control of feline and canine parasites in the tropics. The development of these guidelines required unique and complex considerations to be addressed, often inapplicable to developed nations. Much of the tropics encompass middle-to-low income countries in which poor standards of environmental hygiene and large populations of stray dogs and cats coexist. In these regions, a range of parasites pose a high risk to companion animals, which ultimately may place their owners at risk of acquiring parasitic zoonoses. These considerations led to the development of unique recommendations with regard, for example, to deworming and endoparasite testing intervals for the control of both global and 'region-specific' parasites in the tropics. Moreover, the 'off-' or 'extra'-label use of drugs for the treatment and control of parasitic infections is common practice in many tropical countries and many generic products lack manufacturers' information on efficacy, safety, and quality control. Recommendations and advice concerning the use of such drugs and protocols are also addressed in these guidelines. The formation of these guidelines is an important first step towards improving the education of veterinarians specifically regarding best-practice for the diagnosis, treatment and control of canine and feline parasites in the tropics.

Global prevalence of Toxocara infection in dogs

Dogs serve as the most important definitive hosts for Toxocara canis-a causative agent of human toxocariasis and one of the most widespread zoonotic helminth worldwide. The present study was undertaken to assess the global prevalence of T. canis infection in dogs. PubMed, Scopus, Web of Science, EMBASE and SciELO were searched to identify relevant studies. A random-effects model was used to estimate the overall and the subgroup-pooled prevalences across studies, and heterogeneity was assessed via the I² test. The data were categorized according to WHO-region, different types of dogs, risk factors and environmental variables. From a total of 4370 peer-reviewed publications, 229 articles that studied 13,010,004 dogs in 60 countries met the final inclusion criteria. The overall prevalence of Toxocara infection in dogs was 11.1% (95% CI, 10.6-11.7%). The estimated prevalence in the different WHO-regions ranged from 6.4% to 19.2%: Eastern Mediterranean (19.2%, 13.7-25.5%), Africa (18.5%, 13.7-23.9%), South-East Asia (11.9%, 6.8-18.2%), North America (11.1%, 10.6-11.7%), South America (10.9%, 7.6-14.6%), Europe (10.8%, 8.9-12.9%) and Western Pacific (6.4%, 3.3-10.2%). Young (<1 year of age), stray, rural and male dogs had a significantly (P<0.001) higher prevalence of infection than older, pet, urban or female dogs. The prevalence was higher in low income countries and regions at a low geographical latitude, close to the equator, characterized as having tropical climates. From this review, it is estimated that ≥100 million dogs are infected with Toxocara around the world. This highlights the need for an increased focus on implementing affordable, appropriate control programs to reduce the public health threat of toxocariasis as a zoonosis of global importance.

Prevalence of Toxocara spp. in dogs and cats in South America (excluding Brazil)

Toxocariasis is a worldwide anthropozoonosis caused by Toxocara spp. nematodes. High prevalences of the disease has been found in developing countries, particularly in regions with poor sanitary conditions. The definitive hosts of the nematodes are dogs and cats, which play a vital role in the transmission of this parasite as humans are considered a paratenic host. The epidemiology of the disease in South America is not clear as it is usually not diagnosed and is not a notifiable disease. This review summarizes information regarding prevalence reports of Toxocara spp. in dog and cats in South America (excluding Brazil). Additionally, and in accordance with the one health approach, reports of contaminated soil in public zones and parks as well as infection/prevalence reports in wildlife species by geographical regions are also included. The findings show the importance of awareness among veterinarians and public health authorities about Toxocara spp. as neglected disease.

Ascarids exposed: a method for in vitro drug exposure and gene expression analysis of anthelmintic naïve Parascaris spp

Ascarid parasites infect a variety of hosts and regular anthelmintic treatment is recommended for all species. Parascaris spp. is the only ascarid species with widespread anthelmintic resistance, which allows for the study of resistance mechanisms. The purpose of this study was to establish an in vitro drug exposure protocol for adult anthelmintic-naïve Parascaris spp. and report a preliminary transcriptomic analysis in response to drug exposure. Live worms were harvested from foal necropsies and maintained in RPMI-1640 at 37 °C. Serial dilutions of oxibendazole (OBZ) and ivermectin (IVM) were prepared for in vitro drug exposure, and worm viability was monitored over time. In a second drug trial, worms were used for transcriptomic analysis. The final drug concentrations employed were OBZ at 40.1 μm (10 μg mL-1) and IVM at 1.1 μm (1 μg mL-1) for 24 and 3 h, respectively. The RNA-seq analysis revealed numerous differentially expressed genes, with some being potentially related to drug detoxification and regulatory mechanisms. This report provides a method for in vitro drug exposure and the phenotypic responses for Parascaris spp., which could be extrapolated to other ascarid parasites. Finally, it also provides preliminary transcriptomic data following drug exposure as a reference point for future studies of Parascaris spp.

Sources of environmental contamination with Toxocara spp.: An omnipresent parasite

Embryonated Toxocara eggs in the environment are considered to be the most important source of human toxocariasis. These eggs, however, are also a source of infection for the definitive and paratenic hosts. Most available literature focuses on Toxocara canis in dogs, or other canids. There are, however, other Toxocara species with their accompanying definitive hosts. Results from studies that modelled patent infections in dogs, cats and foxes show that although dogs are a very important source for environmental contamination with Toxocara eggs, other sources cannot be ignored. For a good understanding of the relative contributions of different definitive hosts to environmental contamination with Toxocara eggs, computational models should be built and fed with data from different fields of expertise as is discussed in this paper.

Pathology of larvae and adults in dogs and cats

Endoparasitism remains a significant cause of morbidity and mortality in puppies and kittens. The ascarids of dogs and cats (Toxocara canis, Toxascaris leonina, Toxocara cati) cause significant pathology due to either larval migration or adult nematode burden within the gastrointestinal tract. This chapter will review the important pathologic events and lesions that are encountered during ascarid development in dogs and cats with emphasis given to the characteristic gross pathology lesions that are seen in affected animals.

Prevalence of Toxocara in dogs and cats in Africa

Dogs and cats have a close association with humans providing companionship; however, pets are reservoirs of zoonotic pathogens such as Toxocara. Toxocara canis and Toxocara cati are small intestinal nematodes found in canids and felids, respectively. Infected pets shed thousands of eggs resulting in environmental contamination. Toxocara can infect a wide variety of paratenic hosts including humans, rodents, pigs and chickens. Paratenic hosts become infected by ingestion of the infective eggs containing the third stage larvae or ingestion of dormant larvae in animal tissues. Infected humans may develop visceral larval migrans or ocular toxocariasis. Regular anthelmintic treatment and restricted movement of dogs and cats are recommended to control Toxocara environmental contamination. This paper reviews the prevalence and risk factors of Toxocara in dogs and cats in Africa; and pet owners' awareness of canine zoonotic helminths.

The Effectiveness of Dog Population Management: A Systematic Review

Simple Summary

Domestic dogs are abundant worldwide—as owned pets, unowned strays, and feral animals. High numbers of free-roaming dogs can be a concern because of the risks they pose to public health, animal welfare, and wildlife. Using a systematic review process, we investigated what the research published to date can tell us about the effectiveness of different dog population management methods. We found that management methods for dog populations have been researched in multiple countries worldwide, using a wide range of indicators to assess method effectiveness. We outline the results and suggest improvements to help guide future dog population management policy.

Abstract

The worldwide population of domestic dogs is estimated at approximately 700 million, with around 75% classified as “free-roaming”. Where free-roaming dogs exist in high densities, there are significant implications for public health, animal welfare, and wildlife. Approaches to manage dog populations include culling, fertility control, and sheltering. Understanding the effectiveness of each of these interventions is important in guiding future dog population management. We present the results of a systematic review of published studies investigating dog population management, to assess: (1) where and when studies were carried out; (2) what population management methods were used; and (3) what was the effect of the method. We evaluated the reporting quality of the published studies for strength of evidence assessment. The systematic review resulted in a corpus of 39 papers from 15 countries, reporting a wide disparity of approaches and measures of effect. We synthesised the management methods and reported effects. Fertility control was most investigated and had the greatest reported effect on dog population size. Reporting quality was low for power calculations (11%), sample size calculations (11%), and the use of control populations (17%). We provide recommendations for future studies to use common metrics and improve reporting quality, study design, and modelling approaches in order to allow better assessment of the true impact of dog population management.

Neuroinvasion of Toxocara canis- and T. cati-larvae mediates dynamic changes in brain cytokine and chemokine profile

Background

Neurotoxocarosis (NT) is induced by larvae of the dog or cat roundworm (Toxocara canis or T. cati) migrating and persisting in the central nervous system of paratenic hosts, including humans, and may be accompanied by severe neurological symptoms. Host- or parasite-induced immunoregulatory processes contribute to the pathogenesis, but detailed data on pathogenic mechanisms and involvement of signalling molecules during cerebral Toxocara species infections are scarce.

Methods

To elucidate alterations in immunomodulatory mediator pattern, comprehensive multiplex bead array assays profiling comprising 23 different cytokines and chemokines were performed during the course of T. canis- and T. cati-induced NT. To this end, cerebra and cerebella of experimentally infected C57Bl/6 J mice serving as paratenic host models were analysed at six different time points (days 7, 14, 28, 42, 70 and 98) post infectionem (pi).

Results

Brain-body mass ratios of T. canis and T. cati-infected mice were significantly lower than those of the uninfected control group at day 14 pi, and also at day 28 pi for T. canis-infected mice. Both infection groups showed a continuous decrease of pro-inflammatory cytokine concentrations, including TNF-α, IFN-γ, GM-CSF and IL-6, in the cerebrum over the course of infection. Additionally, T. canis but not T. cati-induced neurotoxocarosis was characterised by significantly elevated levels of anti-inflammatory IL-4 and IL-5 in the cerebrum in the acute and subacute phase of the disease. The higher neuroaffinity of T. canis led to a prominent increase of eotaxin and MIP-1α in both the cerebrum and cerebellum, while in T. cati-infected mice, these chemokines were significantly elevated only in the cerebellum.

Conclusions

The direct comparison of T. canis- and T. cati-induced NT provides valuable insights into key regulatory mechanisms of Toxocara species in paratenic hosts. The cerebral cyto-/chemokine milieu is shifted to a predominantly anti-inflammatory immune response during NT, possibly enabling both survival of the parasite and the neuroinfected paratenic host. Alteration of eotaxin and MIP-1α concentrations are congruent with the higher neuroaffinity of T. canis and species-specific tropism of T. canis to the cerebrum and T. cati to the cerebellum.

Electronic supplementary material

The online version of this article (10.1186/s12974-019-1537-x) contains supplementary material, which is available to authorized users.

Experimental Infection with T. Canis and T. Leonina in Farm Mink (Neovison Vison)

Introduction

Farm mink (Neovison vison) can be naturally exposed to T. canis and T. leonina pathogens on the farm. If mink were hosts, it would imply some veterinary public health as well as animal welfare issues. For this reason, the aim of the study was to determine whether mink might be definitive or paratenic hosts of these parasites.

Material and Methods

Four groups of mink were infected with both parasite species using larvated eggs or feed containing mouse tissue previously infected with the parasites. Following inoculation, the infections were monitored in vivo by faecal examination for 14 weeks p.i., and then western blotting and ELISA were performed.

Results

Coprology did not reveal any canine roundworm eggs, neither were nematodes found in mink intestines during post mortem examination. The specific IgG antibodies recognising excretory/secretory (ES) antigens of both parasite species were identified in mink sera. Single T. leonina tissue larvae were found in digested organs.

Conclusions

Our results confirm that farm mink may contribute both T. canis and T. leonina infections. It was proved that farm mink were not their definitive hosts, and therefore mink faeces need not be considered a source of canine roundworm eggs in any soil it fertilises. Nonetheless, as farm mink may be a paratenic host for both parasite species, this may have some impact on the health and welfare of infected animals.

Histopathological Lesions Caused by Experimental Toxocara Canis and Toxascaris Leonina Infections in Farm Mink (Neovison Vison)

INTRODUCTION

Canine roundworm T. canis and T. leonina infections were investigated in experimentally infected farm mink (Neovison vison) to describe the pattern of pathological lesions in this paratenic host.

MATERIAL AND METHODS

Material and MethodsInfections in mink developed following ingestion of embryonated eggs of either parasite or mice tissue infected with both parasite species.

RESULTS

Comparative analysis of haematoxylin- and eosin-stained slides showed essential differences among the experimental groups. The lesions observed included eosinophil and mononuclear inflammatory infiltrates of the intestinal wall and local lymph nodes, inflammation and haemorrhages in liver tissues, and interstitial inflammation and mineralisation of the kidneys and lungs. Larvae migrating through the minks' bodies also caused particularly salient enlargement of lymphoid follicles in the spleen and inflammatory infiltrates of mononuclear cells in skeletal and heart muscles.

CONCLUSIONS

It is assumed that histopathological lesions appeared as a local and general host response to invasive L3 T. canis and T. leonina larvae migrating through the tissues of infected farm mink. Interestingly, mink infected with embryonated eggs had more pronounced lesions than animals infected with tissue larvae. Detailed histopathological examinations of parenchymal organs and striated muscles revealed lesions resembling those observed in other paratenic host species due to toxocarosis.

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.

Parasitic Nematode and Protozoa Status of Working Sheepdogs on the North Island of New Zealand

Simple Summary

Working farm dogs may be at more risk of infection with gastrointestinal parasites than pet dogs, as they are fed raw meat and are in close contact with other dogs. This study determined the percentage of working farm dogs in New Zealand shedding intestinal parasite stages in their feces and explored what factors might increase or decrease the chance of parasites being in a dog’s feces. One person collected information about the dogs and their management using a questionnaire, body condition scored each dog, and collected a fecal sample to test for parasites. The study found that four out of ten dogs had one or more types of gastrointestinal parasites present in their feces, and this was more common in younger dogs. There was no association between the presence of parasites in feces and frequency that owners reported giving dogs anthelmintic drugs. The high percentage of dogs with parasite lifecycle stages present in their feces is of concern for the health of the dogs and also the owners as some parasites are zoonotic.

Abstract

Working farm dogs in New Zealand may have a high parasitic challenge because of access to raw meat and close contact with other dogs. This cross-sectional study aimed to estimate the percentage of dogs with gastrointestinal nematode and protozoan parasite lifecycle stages present in their feces and to identify factors associated with the presence of parasites. A single researcher collected information about the dogs and their management via a questionnaire, body condition scored (BCS) the dogs, and collected fecal samples to determine the parasite burden. Fecal samples were collected from 171 dogs and 40% (95% CI 33.0% to 47.7%) contained parasite ova or (oo)cysts. There was no association between BCS and the presence of nematodes and parasites (p = 0.74) in the feces. The percentage of dogs with parasites present in their feces was not associated with BCS or the frequency with which anthelmintic drugs were reportedly administered (p = 0.61). The high percentage of dogs with parasites are of concern for the health of the dogs and their owners, given the zoonotic potential of some parasites. Further, research should also focus on understanding why reporting giving anthelmintic drugs at least every three months did not eliminate the infection.

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.

Toxocara eggs in public places worldwide - A systematic review and meta-analysis

Toxocariasis is a neglected tropical disease of humans. Although many studies have indicated or shown that environmental contamination with Toxocara species eggs is a major risk factor for toxocariasis in humans, there has been no comprehensive analysis of published data or information. Here, we conducted the first systematic review and meta-analysis of current literature to assess the global prevalence of Toxocara eggs in public places (including beaches, parks and playgrounds). We conducted searches of the PubMed, Embase, Scopus and Science Direct databases for relevant studies published until 20 April 2018, and assessed the prevalence rates of Toxocara eggs in public places. We used the random effects model to calculate pooled prevalence estimates, with 95% confidence intervals (CIs), and analysed data in relation to WHO geographical regions. Subgroup analysis and meta-regressions regarding the geographical and environmental variables were also performed. Of 2384 publications identified, 109 studies that tested 42,797 soil samples in 40 countries were included in the meta-analysis. The pooled global prevalence of Toxocara eggs in public places was 21% (95% CI, 16-27%; 13,895/42,797). The estimated prevalence rates in the different WHO regions ranged from 13% to 35%: Western Pacific (35%; 95% CI, 15-58%), Africa (27%; 95% CI, 11-47%), South America (25%; 95% CI, 13-33%), South-East Asia (21%; 95% CI, 3-49%), Middle East and North Africa (18%; 95% CI, 11-24%), Europe (18%; 95% CI, 14-22%), and North and Central Americas (13%; 95% CI, 8-23%). A high prevalence was significantly associated with high geographical longitude (P = 0.04), low latitude (P = 0.02) and high relative environmental humidity (P = 0.04). This meta-analysis of data from published records indicates that public places are often heavily contaminated with eggs of Toxocara. This finding calls for measures to reduce the potential risk of infection and disease in humans.

Gastrointestinal Parasites in Shelter Dogs: Occurrence, Pathology, Treatment and Risk to Shelter Workers

Dogs entering shelters can carry gastrointestinal parasites that may pose serious risks to other animals, shelter staff and visitors. Shelters provide an environment that could facilitate the spread of parasitic infections between animals. Nematodes and protozoa that transmit through ingestion or skin penetration are major enteric parasites of concern in shelter settings. Ancylostoma spp., Uncinaria stenocephala, Toxocara canis, Toxascaris leonina, Trichuris vulpis and Dipylidium caninum are the major helminths while Giardia, Cryptosporidium, Isospora spp. and Sarcocystis spp. are the most prevalent protozoan parasites in shelter dogs. The prevalence of gastrointestinal parasites in shelter dogs is typically higher than in owned dogs. A range of cost-effective drugs is available for prevention and control of helminths in shelters, notably fenbendazole, pyrantel, oxantel, and praziquantel. Parasiticide options for protozoan parasites are often cost-prohibitive or limited by a lack of veterinary registration for use in dogs. Environmental control measures reliant upon hygiene and facility management are therefore a mainstay for control and prevention of protozoan parasites in shelters. This philosophy should also extend to helminth control, as integrated parasite control strategies can allow anthelmintics to be used more sparingly and judiciously. The purpose of this article is to comprehensively review the current knowledge on the prevalence of gastrointestinal parasites most commonly found in dogs in shelters, canvass recommended treatment programs in shelter dogs, and to explore the likelihood that parasiticide resistance might emerge in a shelter environment.

Developmental stages and viability of Toxocara canis eggs outside the host

Introducción. La toxocariasis es una enfermedad zoonótica transmitida por contacto con el suelo contaminado y causada principalmente por la ingestión de huevos larvados de Toxocara canis.Objetivos. Estudiar la morfología de los estadios intraovulares en desarrollo de T. canis en cultivo, caracterizar los huevos no viables y las secuencias de las mudas larvarias, y comparar la viabilidad de los huevos en las etapas tempranas de división y al alcanzar la maduración completa.Materiales y métodos. Se observó el desarrollo de los embriones y se caracterizaron los huevos no viables, mediante microscopía de luz. Se comparó la proporción de huevos viables con embrión con la de huevos maduros viables.Resultados. La división celular comenzó 24 horas después de iniciado el cultivo. Los estadios tempranos estuvieron presentes por un periodo de tres a cinco días. Los estadios de desarrollo identificados fueron: huevos con una célula, con dos células, con tres células y con cuatro células; mórula temprana, mórula tardía, blástula, gástrula, renacuajo, prelarva, primer, segundo y tercer estado larvario. Se presentaron dos mudas larvarias. Los huevos no viables tenían el citoplasma degradado, cubierta exterior delgada o colapsada, y su larva no se movía al exponerla a la luz. No se encontraron diferencias significativas entre la proporción de huevos viables del día 5 al día 21, al compararla con la viabilidad de los huevos completamente maduros (30 días).Conclusión. Los embriones en desarrollo en el medio ambiente pueden considerarse como un riesgo potencial para la salud pública. La identificación precisa de los estadios de desarrollo y la clara diferenciación de huevos viables y no viables, pueden ayudar a determinar con exactitud una tasa basal de desarrollo, la cual sería útil en el estudio de compuestos ovicidas.

Molecular characterization of Toxocara spp. eggs isolated from public parks and playgrounds in Shiraz, Iran

Human toxocariasis, a worldwide parasitic disease, is caused by the larval stage of intestinal nematodes of dogs and cats, namely Toxocara canis and Toxocara cati. Human infection occurs by the accidental ingestion of embryonated eggs present in the soil, vegetables or on other contaminated surfaces, as well as via consumption of uncooked paratenic hosts, such as bird meat and giblets. The objective of this study was to evaluate the contamination of soil in public parks and playgrounds in Shiraz using microscopy and molecular methods. A total of 150 soil samples were collected from public parks and playgrounds in various areas of Shiraz, southern Iran. The samples were treated with saturated zinc sulphate solution, and Toxocara spp. eggs were detected by microscopic observation followed by nested polymerase chain reaction (PCR). To differentiate T. canis and T. cati eggs from each other, PCR restriction fragment length polymorphism (RFLP) of the internal transcribed spacer (ITS)-rDNA region by SalI endonuclease enzyme was used. PCR-sequencing was performed to confirm the results of the PCR-RFLP method. Based on the flotation results of the 150 soil samples, six (4%) were found to be positive for Toxocara spp. eggs, whereas nested-PCR showed 24 samples to be positive (16%). Based on the PCR-RFLP method and the sequence of the ITS-rDNA region, a total of 23 out of 24 isolates were confirmed as T. cati and one out of 24 as T. canis. The results showed a higher number of soil samples to be positive for Toxocara by the molecular method than microscopy, and higher T. cati infection in soil samples, which could have an important role in human infection with toxocariasis in this region.

Endocrine immune interactions during chronic Toxocariasis caused by Toxocara canis in a murine model: New insights into the pathophysiology of an old infection

Toxocara canis is the helminth causing Toxocariasis, a parasitic disease with medical and veterinary implications. Their final host are members of the family Canidae and as paratenic hosts, most of the mammals are sensitive (man, rat, mouse, among others). It has been reported that a pituitary hormone, prolactin, it is responsible for reactivation and migration of larvae to the uterus and mammary gland during the last third of gestation in bitches. In addition, this hormone has been shown to play an important role in the regulation of the immune response. Thus, the aim of this study, was to evaluate the effect of hypophysectomy in the rat model of Toxocariasis, on the immune response against this parasite during a chronic infection, for which parasite loads were analyzed in different organs (lung and brain). Furthermore, serum specific antibody titers, and percentages of different cells of the immune system were also determined. The results showed a decrease in the number of larvae recovered from lung and brain in the hypophysectomized animals. In this same group of animals, there was no production of specific antibodies against the parasite. As for the percentages of the cells of the immune system, there are differences in some subpopulations due to surgery and others due to infection. Our results demonstrated that the lack of pituitary hormones alters parasite loads and the immune response to the helminth parasite Toxocara canis.

Endoparasites of Wild Mammals Sheltered in Wildlife Hospitals and Rehabilitation Centres in Greece

Wildlife parasitic diseases represent an important field of investigation as they may have a significant impact on wild animals’ health and fitness, and may also have zoonotic implications. This study aimed to investigate the occurrence of endoparasites in wild mammals admitted to wildlife hospitals and rehabilitation centres in Greece. Sixty-five animals belonging to 17 species and originated from various areas of continental and insular Greece were included in the survey. The most numerous animal species examined were hedgehogs (n = 19), red foxes (n = 16), and European roe deer (n = 6). Faecal samples were collected individually and examined by floatation and sedimentation method. Parasites were found in 46 (70.7%) of the animals. Most parasites found in canids, felids, and ruminants are of great relevance to the domestic animals’ health and some of them are also of zoonotic importance. To the best of the author’s knowledge, this is the first report of endoparasites in hedgehogs, roe deers, fallow deers, badgers, and bats, and the first report of the pulmonary nematode Troglostrongylus brevior in a wild cat in Greece. The significance of the parasites found in each animal species in regard to their health and their relevance to domestic animals and human health is discussed.

Occurrence and zoonotic potential of endoparasites in cats of Cyprus and a new distribution area for Troglostrongylus brevior

The present study investigated for the first time the occurrence of pulmonary and intestinal parasites of cats in Cyprus. Cats from five districts of Cyprus (Lefkosia, Lemesos, Larnaka, Pafos and Ammochostos) were examined by classical parasitological methods and the identity of lungworm larvae, whenever present, was confirmed by PCR-coupled sequencing. A total of 185 cats, 48 living exclusively indoors and 137 with outdoor access, were included in the study. Parasites were found in 66 (35.7%) of the examined cats, i.e. Toxocara cati (12%), Cystoisospora rivolta (12%), Joyeuxiella/Diplopylidium spp. (7%), Giardia spp. (6.5%), Troglostrongylus brevior (5%), Cystoisospora felis (2.5%), Aelurostrongylus abstrusus (2%), Taenia spp. (0.5%) and Dipylidium caninum (0.5%). Mixed infections were recorded in 18 cats. Cats that lived exclusively indoors or had received an antiparasitic treatment in the last 6 months were less likely to be infected (p < 0.05). Moreover, cats younger than 1 year old were more likely to shed first-stage larvae of T. brevior (p = 0.04). The present study shows that cats in Cyprus are infected at a high percentage by a variety of parasites that potentially affect their health and also, in some cases (i.e. T. cati, D. caninum, Giardia spp.), may have an impact on human health. Moreover, it was revealed that T. brevior, a lungworm of emerging significance, is present on the island, rendering Cyprus the easternmost distribution border of this parasite in Europe to date.