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1.
Exp Parasitol ; 261: 108753, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38621506

ABSTRACT

Toxocara cati and T. canis are parasitic nematodes found in the intestines of cats and dogs respectively, with a cosmopolitan distribution, and the potential for anthropozoonotic transmission, resulting in human toxocariasis. Spread of Toxocara spp. is primarily through the ingestion of embryonated eggs contaminating surfaces or uncooked food, or through the ingestion of a paratenic host containing a third-stage larva. The Toxocara spp. eggshell is composed of a lipid layer providing a permeability barrier, a chitinous layer providing structural strength, and thin vitelline and uterine layers, which combined create a biologically resistant structure, making the Toxocara spp. egg very hardy, and capable of surviving for years in the natural environment. The use of sodium hypochlorite, household bleach, as a disinfectant for Toxocara spp. eggs has been reported, with results varying from ineffective to limited effectiveness depending on parameters including contact time, concentration, and temperature. Desiccation or humidity levels have also been reported to have an impact on larval development and/or survival of Toxocara spp. eggs. However, to date, after a thorough search of the literature, no relevant publications have been found that evaluated the use of sodium hypochlorite and desiccation in combination. These experiments aim to assess the effects of using a combination of desiccation and 10% bleach solution (0.6% sodium hypochlorite) on fertilized or embryonated eggs of T. cati, T. canis, and T. vitulorum. Results of these experiments highlight the synergistic effects of desiccation and bleach, and demonstrate a relatively simple method for surface inactivation, resulting in a decrease in viability or destruction of T. cati, T. canis and T. vitulorum eggs. Implications for these findings may apply to larger scale elimination of ascarid eggs from both research, veterinary, and farming facilities to mitigate transmission.


Subject(s)
Desiccation , Sodium Hypochlorite , Toxocara , Animals , Sodium Hypochlorite/pharmacology , Toxocara/drug effects , Toxocara/physiology , Ovum/drug effects , Disinfectants/pharmacology , Dogs , Toxocariasis/parasitology , Toxocariasis/prevention & control , Female , Cats , Toxocara canis/drug effects , Toxocara canis/physiology , Larva/drug effects
2.
Parasitology ; 149(1): 1-9, 2022 01.
Article in English | MEDLINE | ID: mdl-34694217

ABSTRACT

Human toxocariasis is a neglected tropical disease, which is actually global in distribution and has a significant impact on global public health. The infection can lead to several serious conditions in humans, including allergic, ophthalmic and neurological disorders such as epilepsy. It is caused by the common roundworm species Toxocara canis and Toxocara cati, with humans becoming accidentally infected via the ingestion of eggs or larvae. Toxocara eggs are deposited on the ground when infected dogs, cats and foxes defecate, with the eggs contaminating crops, grazing pastures, and subsequently food animals. However, transmission of Toxocara to humans via food consumption has received relatively little attention in the literature. To establish the risks that contaminated food poses to the public, a renewed research focus is required. This review discusses what is currently known about food-borne Toxocara transmission, highlighting the gaps in our understanding that require further attention, and outlining some potential preventative strategies which could be employed to safeguard consumer health.


Subject(s)
Nervous System Diseases , Toxocara canis , Toxocariasis , Animals , Brain , Dogs , Humans , Toxocara , Toxocariasis/epidemiology , Toxocariasis/prevention & control , Toxocariasis/transmission , Zoonoses
3.
Parasitol Res ; 119(10): 3369-3376, 2020 Oct.
Article in English | MEDLINE | ID: mdl-32556502

ABSTRACT

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.


Subject(s)
Antinematodal Agents/pharmacology , Cresols/pharmacology , Disinfectants/pharmacology , Toxocara canis/drug effects , Toxocariasis/prevention & control , Animals , Embryonic Development/drug effects , Female , Larva/drug effects , Larva/growth & development , Mice , Ovum/drug effects , Ovum/growth & development , Parasite Load , Toxocara canis/growth & development , Toxocariasis/parasitology
4.
J Helminthol ; 94: e60, 2019 Jul 12.
Article in English | MEDLINE | ID: mdl-31630692

ABSTRACT

Toxocara canis (Werner, 1782) is a zoonotic nematode commonly parasitizing dogs worldwide with great public health importance as the aetiological agent of human toxocariasis. In this respect, the aim of this study was to evaluate the effect of six disinfectant products commonly used in kennels, veterinary clinics and as household cleaning products on the embryogenesis and viability of T. canis eggs. The composition of active ingredients in these commercial disinfectants was sodium hypochlorite (A); a mix of N-(3-aminopropyl)-N-dodecylpropan-1.3-diamine and didecyldimethylammonium chloride (B); sodium dichloroisocyanurate dehydrate (C); a mix of glutaraldehyde, quaternary ammonium compounds, benzyl-c12-18-alkyldimethyl and chlorides (D); a mix of 2-propanol, ethanol, benzalkonium chloride and glucoprotamin (E); a mix of pentapotassium bis (peroxymonosulphate) bis (sulphate), sodium C10-13-alkylbenzenesulphonate, malic acid, sulphamidic acid, sodium toluenesulphonate, dipotassium peroxodisulphate and dipentene (F). After dilution, the tested disinfectants had the maximal concentration recommended by the manufacturer in order to achieve a biocidal effect. Each product was tested on approximately 10,000 T. canis eggs, having five different contact times (5, 10, 15, 30, 60 min). Three replicates were tested for each diluted disinfectant and for each contact time. After the treatment, eggs were washed and incubated in distilled water at 27 °C for 2 weeks. None of the tested products had a significant inhibitory effect on the embryogenesis and viability of T. canis eggs, regardless of the contact time. Moreover, after 2 weeks, in all tested samples, eggs containing motile infective larvae were identified, showing that routinely used disinfectants do not eliminate risk of infection by T. canis.


Subject(s)
Disinfectants/pharmacology , Disinfection/standards , Larva/drug effects , Ovum/drug effects , Toxocara canis/drug effects , Animals , Disinfectants/chemistry , Dogs , Female , Toxocariasis/parasitology , Toxocariasis/prevention & control
5.
Parasitology ; 144(1): 81-94, 2017 01.
Article in English | MEDLINE | ID: mdl-26670118

ABSTRACT

Toxocara species infect a wide range of companion, domestic and wild animals as definitive and paratenic hosts, via multiple routes of transmission, producing long-lived tissue-inhabiting larvae and resistant eggs that can survive in the external environment. Therefore Toxocara and the disease it causes in humans, toxocariasis, represents an ideal aetiological agent for the development of the one health approach. However, despite increasing awareness of the public health significance of toxocariasis, gaps in our understanding of certain key aspects of the parasite's biology and epidemiology remain. These gaps hinder our ability to integrate research effort within the veterinary, medical and environmental disciplines. This review will highlight key deficits in our understanding of nine dimensions of Toxocara epidemiology and discuss a potential scenario to develop a more integrated, one health approach to improve our understanding of the prevention and control of this complex and cryptic zoonosis.


Subject(s)
Host-Parasite Interactions , Toxocara/physiology , Toxocariasis/epidemiology , Animals , Disease Management , Dogs , Environment , Global Health , Humans , Public Health , Toxocara/isolation & purification , Toxocara canis/isolation & purification , Toxocariasis/parasitology , Toxocariasis/prevention & control , Zoonoses
6.
Parasite Immunol ; 38(5): 326-30, 2016 05.
Article in English | MEDLINE | ID: mdl-26971490

ABSTRACT

In this study, supplementation with the probiotic Saccharomyces boulardii promoted a reduction in intensity of infection by Toxocara canis and modulates cytokines mRNA expression in experimentally infected mice. IL-12 gene transcription had 40-fold increase in S. boulardii supplemented uninfected mice and sevenfold increase in supplemented infected mice comparing with not supplemented group. Regarding IFNγ, similar results were observed, since probiotic supplementation induced approximately 43-fold increase, but only in uninfected mice (P < 0·05). T. canis infection upregulated IL-10 expression while S. boulardii downregulated it and no change was observed for IL-4. Thus, based in these findings; we suggest that one possible mechanism responsible for S. boulardii protection effect against T. canis infection is by the modulation of cytokines expression, especially IL-12.


Subject(s)
Interferon-gamma/immunology , Interleukin-12/immunology , Probiotics/administration & dosage , Saccharomyces boulardii , Toxocara canis/physiology , Toxocariasis/immunology , Toxocariasis/prevention & control , Animals , Cytokines/immunology , Female , Mice
7.
Wien Med Wochenschr ; 164(19-20): 392-9, 2014 Oct.
Article in English | MEDLINE | ID: mdl-25358598

ABSTRACT

Parasitic infections cause significant ophthalmic disease, both in developing countries and in the Western world. The parasitic infections Acanthamoeba keratitis, ocular toxoplasmosis, and ocular toxocariasis are responsible for a significant proportion of ocular pathology. Especially in light of the recent increase of immunocompromised (i.e. using immunosuppressants or HIV) and aged populations, parasitic infections of the eye are rising in number. This reviews aims to describe the pathogenesis, symptoms, diagnosis and management of infection, as well as preventative measures for these three parasitic ocular diseases.


Subject(s)
Acanthamoeba Keratitis/diagnosis , Toxoplasmosis, Ocular/diagnosis , Acanthamoeba Keratitis/epidemiology , Acanthamoeba Keratitis/prevention & control , Acanthamoeba Keratitis/therapy , Cross-Sectional Studies , Developing Countries , Humans , Toxocariasis/diagnosis , Toxocariasis/epidemiology , Toxocariasis/prevention & control , Toxocariasis/therapy , Toxoplasmosis, Ocular/epidemiology , Toxoplasmosis, Ocular/prevention & control , Toxoplasmosis, Ocular/therapy , Western World
8.
Parasitol Res ; 112(6): 2171-5, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23494157

ABSTRACT

Human toxocariasis is a neglected parasitic zoonosis of worldwide distribution. The consumption of raw or undercooked meat and offal from paratenic hosts of the Toxocara canis nematode can cause infection in humans, but there have been a lack of studies examining specific prophylactic measures to combat this mode of transmission. The aim of this study was to evaluate the establishment of infection by T. canis larvae at the initial and chronic phases of visceral toxocariasis after the consumption of mouse liver subjected to cold treatment. This study was divided into two stages using groups (G) of five donor mice inoculated with 2,000 eggs of T. canis. Two days post-inoculation, the livers of donor mice in G1 and G2 were kept at -20 °C and between 0 and 4 °C, respectively, for 10 days. In the first stage of the study, the livers of mice from G1, G2, and G3 (control) were subjected to a tissue digestion technique and found to be positive for infection. In the second stage, which evaluated infection in mice that had consumed livers from donor mice, receiver mice of G4 and G7 were fed with livers of donor mice from G1 (freezing), receiver mice of G5 and G8 were fed with livers of donor mice from G2 (cooling), and receiver mice of G6 and G9 with livers from G3 (control). Then, the tissue digestion technique was performed for recovering larvae from organs and carcasses of mice, at 2 days (G4, G5, and G6) and 60 days after liver consumption (G7, G8, and G9). It was observed that freezing inhibited the viability of 100 % of the larvae, while cooling promoted 87.7 and 95.7 % reductions in the intensity of infection at 2 and 60 days after liver consumption, respectively. Under the studied conditions, cold treatment shows great potential to help control this parasitosis, both in the initial and chronic phases of toxocariasis.


Subject(s)
Food Technology/methods , Foodborne Diseases/prevention & control , Foodborne Diseases/parasitology , Liver/parasitology , Toxocara canis/radiation effects , Toxocariasis/prevention & control , Toxocariasis/parasitology , Animal Structures/parasitology , Animals , Disease Models, Animal , Foodborne Diseases/pathology , Freezing , Larva/radiation effects , Mice , Refrigeration , Survival Analysis , Toxocara canis/isolation & purification , Toxocariasis/pathology
9.
J Parasitol ; 109(1): 15-19, 2023 01 01.
Article in English | MEDLINE | ID: mdl-36805241

ABSTRACT

Experimental studies have demonstrated the potential of probiotics to control visceral toxocariasis, which is a tissue parasitosis that is difficult to treat. This study evaluated the in vitro activity of probiotics and their supernatants on Toxocara canis larvae. The probiotics Lactobacillus rhamnosus (ATCC 7469), Lactobacillus paracasei (ATCC 335), Saccharomyces boulardii, Saccharomyces cerevisiae, and Bacillus cereus var. toyoi were tested in the following preparations: probiotic (P) 1 × 102 to 1 × 109 colony-forming units (CFUs), inactivated probiotic (IP) 1 × 102 to 1 × 109 CFUs, supernatant probiotic (SUpP), and inactivated probiotic supernatant (SupIP). The probiotics and their respective supernatants were separately incubated with 100 T. canis larvae per well using microculture plates with RPMI-1640 medium for 48 hr at 37 C and 5% CO2. The evaluation of the in vitro tests was based on the viability of T. canis larvae, through morphologic integrity, positive motility, and the absence of trypan blue stain. Only culture supernatants (SUpP and SUpIP) of Lactobacillus spp. resulted in 100% dead larvae, whereas S. boulardii showed larvicidal activity in T. canis >70%. The rest of the tests did not show larvicide activity. Therefore, it is important to investigate the supernatant effects of Lactobacillus spp. and S. boulardii in vivo on T. canis visceral infections, their mechanisms of action, and major metabolites involved.


Subject(s)
Canidae , Probiotics , Saccharomyces boulardii , Toxocara canis , Toxocariasis , Animals , Lactobacillus , Toxocariasis/prevention & control , Larva
10.
Drug Ther Bull ; 61(1): 7-11, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36543343

ABSTRACT

Toxocara canis (from dogs) is recognised as a potential cause of human toxocarosis, but Toxocara cati (from cats) and other species (eg, Toxascaris leonina found in foxes) are also possible causes. Most colonisation with Toxocara species does not lead to symptomatic infection in well-cared for adult animals; young and debilitated animals are at greater risk. Humans can acquire infection from infected animals, for example, via soil contaminated with faeces; however, most human infections are asymptomatic, with symptomatic infection being very rare in the UK. The risk of human infection is reduced by measures such as hand washing and responsible disposal of dog faeces. Some organisations recommend regular prophylactic treatment of pet dogs and cats. However, there are concerns that some parasiticides are contaminating the environment. As an example of a One-Health problem there is a potential conflict between the needs of animal health, human health and the health of the wider ecosystem. Also, considering that only about 5% of non-juvenile household dogs shed Toxocara eggs at a given time, it has been questioned whether it is worthwhile to invest in frequent blind treatments. British veterinary organisations have suggested less frequent treatment may be more appropriate and should be based on individual risk assessment and faecal examinations for worms rather than blanket regular prophylactic treatment, which could reduce the impact of parasiticides on the environment without greatly increasing the risks to animal or human health.


Subject(s)
Cat Diseases , Dog Diseases , Toxocariasis , Adult , Humans , Animals , Dogs , Cats , Ecosystem , Dog Diseases/epidemiology , Dog Diseases/prevention & control , Toxocariasis/epidemiology , Toxocariasis/prevention & control , Toxocara , Antiparasitic Agents , Feces , Foxes , United Kingdom/epidemiology
11.
Vaccine ; 40(6): 912-923, 2022 02 07.
Article in English | MEDLINE | ID: mdl-35012775

ABSTRACT

Toxocariasis is a neglected parasitic zoonosis of global importance. The development of a formulation that can be used as a vaccine would help the definitive control of the infection. Preclinical studies selected two recombinant T. canis proteins (rTcVcan and rTcCad) which significantly protected mice against larval migration. In the present work, these proteins plus three adjuvants (Alhydrogel®, PAM3CSK4®, and Quil-A®) were used to immunize mice against toxocariasis; blood samples were collected three times to measure IgG (total, IgG1, IgG2a), IgA, and IgE via indirect ELISA. Cytokines (IL-5, TNF-α, and IL-10) were measured in splenocytes supernatant, and T. canis larvae were quantified in tissues. The best protein + adjuvant pair found (rTVcan + QuialA®) was then used to immunize T. canis-free puppies (n = 18) that were experimentally infected with T. canis and T. canis naturally-infected puppies (n = 6). Immunoglobulin (IgA, IgE, IgG, IgG1, and IgG2a), parasite load (eggs in feces), number of expelled adults and eggs extracted from the female uterus, and their fertility percentages were analyzed. In mice, it was observed a highly significant reduction (73%) of tissue larvae, a mixed cytokine profile (Th1/Th2), and anti-T. canis antibody titers (IgG, IgG1, IgG2a) using rTVcan + QuialA® mix. In canines, rTVcan + QuialA® promoted reduction in the parasite eggs in feces (95%) and eggs reduction obtained from the uteri of pharmacologically expelled adult females (58.38%). In our knowledge this is the first canine clinical trial of a vaccine with T. canis recombinant proteins. The formulation used has been shown to efficiently stimulate the production of antibodies against infection by T. canis. In the canine, a significant reduction in the number of eggs expelled by the experimental animals that received the formulation prophylactically was evidenced. Future tests should be developed to evaluate the duration of the protective effect and analyze other immune pathways that could be stimulated by the formulation used.


Subject(s)
Toxocara canis , Toxocariasis , Animals , Disease Models, Animal , Dogs , Female , Immunization , Immunoglobulin G , Mice , Recombinant Proteins , Toxocariasis/parasitology , Toxocariasis/prevention & control
12.
MMWR Morb Mortal Wkly Rep ; 60(22): 734-6, 2011 Jun 10.
Article in English | MEDLINE | ID: mdl-21659981

ABSTRACT

Ocular toxocariasis (OT) is caused by the zoonotic parasites Toxocara canis and Toxocara cati, roundworms of dogs and cats. Persons become infected with Toxocara when they unintentionally ingest embryonated eggs that have been shed in the feces of infected animals. Although OT is uncommon, it most often affects young children and can cause debilitating ophthalmologic disease, including blindness. Previous studies of OT in the United States have been conducted in single institutions. This report describes the results of a web-based survey distributed to uveitis, retinal, and pediatric ophthalmology specialists nationwide to collect epidemiologic, demographic, and clinical information on patients with OT. A total of 68 patients were newly diagnosed with OT from September 2009 through September 2010. Among the 44 patients for whom demographic information was available, the median patient age was 8.5 years (range: 1-60 years), and 25 patients (57%) lived in the South at the time of diagnosis. Among 30 patients with reported clinical data, the most common symptom was vision loss, reported by 25 (83%) patients; of these, 17 (68%) suffered permanent vision loss. The results of this first national level survey demonstrate that OT transmission continues to occur in the United States, frequently affecting children and causing permanent vision loss in the majority of reported patients. Good hygiene practices, timely disposal of pet feces, and routine deworming of pets are strategies necessary to reduce OT in humans.


Subject(s)
Toxocara canis/isolation & purification , Toxocariasis/complications , Toxocariasis/epidemiology , Vision Disorders/parasitology , Adolescent , Adult , Animals , Cats , Child , Child, Preschool , Dogs , Enzyme-Linked Immunosorbent Assay , Female , Health Surveys , Humans , Infant , Male , Middle Aged , Ophthalmology/statistics & numerical data , Toxocariasis/prevention & control , United States/epidemiology
13.
Public Health ; 125(2): 90-2, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21295801

ABSTRACT

OBJECTIVES: To undertake a systematic review of articles on the prevention of dog fouling. STUDY DESIGN: Systematic review. METHODS: Literature searches were conducted using six major electronic databases. Published and unpublished material was considered, with no restrictions on date or language. A total of 47 other databases and websites were interrogated. Articles were hand searched for references that had not been identified in the electronic search. Only controlled trials or observational studies assessing the impact of any intervention on the prevention of dog fouling were liable for inclusion in the systematic review. RESULTS: The search identified a total of 68 articles, none of which fulfilled the inclusion criteria. CONCLUSIONS: The review did not find any good-quality studies which have looked at interventions to prevent dog fouling. According to the Cochrane Collaboration, reviews that are unable to find any relevant studies are particularly useful because they highlight important gaps in our knowledge. It is recommended that research is commissioned to answer the important question of what interventions actually work to prevent dog fouling. Methods for performing this research are suggested.


Subject(s)
Dog Diseases/prevention & control , Dog Diseases/transmission , Feces/parasitology , Toxocara canis , Toxocariasis/prevention & control , Animals , Bibliometrics , Dog Diseases/parasitology , Dogs , Feces/microbiology , Soil/parasitology , Toxocariasis/transmission
14.
Article in English | MEDLINE | ID: mdl-33533812

ABSTRACT

Human toxocariasis consists of chronic tissue parasitosis that is difficult to treat and control. This study aimed to evaluate the action of the probiotic Lactobacillus acidophilus ATCC 4356 on larvae of Toxocara canis and the effect of IFN-γ cytokine on parasite-host in vivo (1.109 CFU) and in vitro (1.106, 1.107, 1.108, 1.109 CFU) interactions. Four groups of six BALB/c mice were formed: G1 - L. acidophilus supplementation and T. canis infection; G2 - T. canis infection; G3 - L. acidophilus supplementation; and G4 - PBS administration. Mice were intragastrically suplemented with probiotics for 15 days before inoculation and 48 h after inoculation with 100 T. canis eggs. The inoculation of T. canis was also perfomed intragastrically. The recovery of larvae took place through digestion of liver and lung tissues; the evaluation of IFN-γ gene transcription in leukocytes was performed by qPCR. The in vitro test consisted of incubating the probiotic with T. canis larvae. The supplementation of probiotics produced a reduction of 57.7% (p = 0.025) in the intensity of infection of T. canis larvae in mice, whereas in the in vitro test, there was no larvicidal effect. In addition, a decrease in the IFN-γ gene transcription was observed in both, T. canis-infected and uninfected mice, regardless of whether or not they received supplementation. The probiotic L. acidophilus ATCC 4356 reduced T. canis infection intensity in mice, however, the probiotic did not have a direct effect on larvae, demonstrating the need of interaction with the host for the beneficial effect of the probiotic to occur. Yet, the proinflammatory cytokine IFN-γ did not apparently contributed to the observed beneficial effect of probiotics.


Subject(s)
Lactobacillus acidophilus/drug effects , Probiotics/administration & dosage , Toxocara canis/drug effects , Toxocariasis/drug therapy , Toxocariasis/prevention & control , Animals , Lactobacillus , Larva/drug effects , Mice , Mice, Inbred BALB C , Probiotics/pharmacology , Toxocara canis/microbiology , Toxocara canis/physiology , Toxocariasis/parasitology
15.
Ocul Immunol Inflamm ; 29(7-8): 1265-1276, 2021 Nov 17.
Article in English | MEDLINE | ID: mdl-33909531

ABSTRACT

PURPOSE: Ocular toxocariasis (OT) is a zoonotic infection caused by larval stages of Toxocara canis and T. cati. The current review and meta-analysis aimed to evaluate the global prevalence of OT. METHODS: Five English (PubMed, Scopus, Science Direct, Web of Science, and Google Scholar) databases were explored and 101 articles met the inclusion criteria. RESULTS: The pooled prevalence (95% confidence interval) of OT was higher in immunological studies (9%. 6-12%) than in studies that applied ophthalmic examination (1%. 1-2%). The lower middle-income level countries had the highest prevalence (6%. 2-12%) as well as the African region (10%. 7-13%). The highest infection rate (4%. 2-7%) was detected in the 1-25 mean age group. CONCLUSION: Regular anthelminthic treatment of cats and dogs, and removal of animal feces from public places must be considered.


Subject(s)
Eye Infections, Parasitic/epidemiology , Toxocariasis/epidemiology , Zoonoses/epidemiology , Animals , Anthelmintics/therapeutic use , Cat Diseases/epidemiology , Cat Diseases/prevention & control , Cats , Dog Diseases/epidemiology , Dog Diseases/prevention & control , Dogs , Eye Infections, Parasitic/prevention & control , Eye Infections, Parasitic/veterinary , Humans , Toxocara canis , Toxocariasis/prevention & control , Zoonoses/prevention & control
16.
Trop Anim Health Prod ; 42(2): 309-14, 2010 Feb.
Article in English | MEDLINE | ID: mdl-19697149

ABSTRACT

Toxocara (Neoascaris) vitulorum is a gastrointestinal nematode parasite of young ruminants, responsible for high mortality rates in parasitized cattle and buffalo calves. The objective of this work was to compare the predatory capacity under laboratory conditions of four fungal isolates of the nematophagous fungus Pochonia chlamydosporia (VC1, VC4, VC5 and VC12) on T. vitulorum eggs in 2% water-agar (2% WA). T. vitulorum eggs were plated on 2% WA Petri dishes which contained cultured fungal isolates and control plates without fungi. After 10 and 15 days one hundred eggs were removed and classified according to the following parameters: type 1, biochemical and physiological effect without morphological damage to the eggshell, type 2, lytic effect with morphological alteration of the eggshell and embryo and type 3, lytic effect with morphological alteration of eggshell and embryo in addition to hyphal penetration and internal egg colonization. The fungal isolates were effective in the destruction of T. vitulorum eggs presenting the type 3 effect at 10 and 15 days after contact with the fungus. No nematophagous fungi were observed in the control group during the experiment. There was no variation in the predatory capacity of the fungal isolates (P > 0.01) at the intervals of 10 and 15 days. These results indicate that P. chlamydosporia (VC1, VC4, VC5 and VC12) negatively influenced the development of T. vitulorum eggs and can be considered a potential candidate for the biological control of nematodes.


Subject(s)
Cattle Diseases/parasitology , Hypocreales/physiology , Toxocara/microbiology , Toxocariasis/parasitology , Animals , Cattle , Cattle Diseases/prevention & control , In Vitro Techniques , Pest Control, Biological/methods , Statistics, Nonparametric , Toxocariasis/prevention & control
17.
Vaccine ; 38(30): 4762-4772, 2020 06 19.
Article in English | MEDLINE | ID: mdl-32451213

ABSTRACT

Toxocariasis, a natural helminth infection of dogs and cats caused by Toxocara canis and T. cati, respectively, that are transmitted to mammals, including humans. Infection control is based currently on periodic antihelmintic treatment and there is a need for the development of vaccines to prevent this infection. MATERIALS AND METHODS: Eight potential vaccine candidate T. canis recombinant proteins were identified by in silico (rTcGPRs, rTcCad, rTcVcan, rTcCyst) and larval proteomics (rTES26, rTES32, rMUC-3 and rCTL-4) analyses. Immunogenicity and protection against infectious challenge for seven of these antigens were determined in a murine model of toxocariasis. C57BL/6 female mice were immunized with each of or combinations of recombinant antigens prior to challenge with 500 T. canis embryonated eggs. Levels of specific antibodies (IgG, IgG1, IgG2a and IgE) in sera and cytokines (IL-5, INF-É£ and IL-10) produced by antigens-stimulated splenocytes, were measured. Presence of specific antibodies to the molecules was measured in sera of T. canis-seropositive dogs and humans. RESULTS: All seven molecules were immunogenic in immunized mice; all stimulated significantly elevated levels of specific IgG, IgG1 or IgG2a and six were associated with elevated levels of specific IgE; all induced elevated production of IFN- É£ and IL-10 by splenocytes, but only the in silico-identified membrane-associated recombinants (rTcCad, rTcVcan, and rTcCyst) induced significantly increased IL-5 production. Vaccination with two of the latter (rTcCad and rTcVcan) reduced larval loads in the T. canis challenged mice by 54.3% and 53.9% (P < 0.0001), respectively, compared to unimmunized controls. All seven recombinants were recognized by T. canis-seropositive dog and human sera. CONCLUSION: The identification of vaccine targets by in silico analysis was an effective strategy to identify immunogenic T. canis proteins capable of reducing larval burdens following challenge with the parasite. Two recombinant proteins, rTcCad and rTcVcan, were identified as promising vaccine candidates for canine toxocariasis.


Subject(s)
Cat Diseases , Dog Diseases , Toxocara canis , Toxocariasis , Animals , Cats , Disease Models, Animal , Dogs , Female , Mice , Mice, Inbred C57BL , Recombinant Proteins/genetics , Toxocariasis/prevention & control
18.
Adv Parasitol ; 109: 275-290, 2020.
Article in English | MEDLINE | ID: mdl-32381202

ABSTRACT

Human toxocariasis is a parasitic disease transmitted usually from dogs and/or cats that are infected with Toxocara species, and can be associated with a range of allergic, neurological and/or visual disorders. Recent epidemiological research has estimated that ~1.4 billion people worldwide, particularly in subtropical and tropical regions, are infected with, or exposed to Toxocara species, indicating that human toxocariasis is a neglected tropical disease. Here, we review recent research efforts, consider risk factors, discuss limitations in current seroprevalence estimates, and propose some future research directions towards improved awareness, surveillance, prevention and control of this neglected disease.


Subject(s)
Global Health/statistics & numerical data , Toxocariasis/epidemiology , Animals , Humans , Risk Factors , Seroepidemiologic Studies , Toxocariasis/diagnosis , Toxocariasis/prevention & control
19.
Trop Biomed ; 37(1): 89-102, 2020 Mar 01.
Article in English | MEDLINE | ID: mdl-33612721

ABSTRACT

Toxocara canis is a major parasite that infects many animals with high risk of human infections. This study aims at assessing the immunization with gamma radiationattenuated infective stage on rats challenged with non-irradiated dose. Level of vaccine protection was evaluated in liver and lung regarding parasitological, histopathological, biochemical and molecular parameters. Fifty rats were enrolled in three groups: group A (10 rats) as normal control; group B (20 rats) subdivided into subgroup B1 (infected control) and subgroup B2 infected then challenged after 14 days with the same dose of infection (challenged infected control); and group C (20 rats) subdivided into subgroup C1 vaccinated with a dose of 800 gray (Gy) gamma-radiated infective eggs (vaccine control) and subgroup C2 vaccinated then challenged on 14th day with same number of infective eggs (vaccinated-challenged). Tissues were stained with Haematoxylin and Eosin (H and E) for histopathological studies. Biochemical studies through detection of nitric oxide (NO) and Caspase-3 were conducted. Extent of DNA damage by Comet assay was assessed. Vaccinated-challenged subgroup revealed a marked reduction in larvae in tissues with mild associated histological changes. In addition there was accompanied reduction of NO, Casepase-3 level and DNA damage compared to the control infected group. It could be concluded that vaccination of rats with a dose of 800Gy gamma radiation-attenuated infective stage improves immune response to challenge infection and drastically reduces the morbidity currently seen.


Subject(s)
Ovum/radiation effects , Toxocariasis/prevention & control , Vaccination , Animals , Caspase 3/analysis , Comet Assay , Gamma Rays , Liver/parasitology , Liver/pathology , Lung/parasitology , Lung/pathology , Male , Nitric Oxide/analysis , Rats , Toxocariasis/immunology , Vaccines, Attenuated
20.
Adv Parasitol ; 109: 3-16, 2020.
Article in English | MEDLINE | ID: mdl-32381204

ABSTRACT

Toxocara sp. are zoonotic parasitic roundworms that cause infection and morbidity in both developed and developing countries. In humans, infection is thought to be most common in children, particularly those living in poverty, and usually results from consumption of soil contaminated with parasite eggs deposited by dog or cat faeces. Infection in humans results in different clinical manifestations, some more overt like visceral or ocular larva migrans and others more cryptic like neurocognitive delay. Despite its pervasiveness, toxocariasis has become a neglected infection. We review the dynamics of the human-animal interface in the context of this parasite, discuss the challenges in controlling transmission to humans, and cite key areas of research that could enable improved interventions. With political will and proper resource allocation, we propose that effective interventions are possible in the near term.


Subject(s)
Pets/parasitology , Toxocara/physiology , Toxocariasis/parasitology , Zoonoses/parasitology , Animals , Human-Animal Interaction , Humans , Toxocariasis/prevention & control , Toxocariasis/transmission , Zoonoses/prevention & control , Zoonoses/transmission
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