1
|
Khatir AA, Mousavi F, Sepidarkish M, Arshadi M, Arjmandi D, Aldaghi M, Rostami A. Association between Alzheimer's disease and Toxocara infection/exposure: a case-control study. Trans R Soc Trop Med Hyg 2024:trae039. [PMID: 38899453 DOI: 10.1093/trstmh/trae039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 05/08/2024] [Accepted: 06/03/2024] [Indexed: 06/21/2024] Open
Abstract
BACKGROUND Infections may contribute to Alzheimer's disease (AD) risk. Limited evidence suggests Toxocara spp. infection/exposure could influence AD development. METHODS We investigated Toxocara seropositivity and AD in Iranian adults using a matched case-control study. Our sample included 90 AD cases and 91 healthy older adults. Anti-Toxocara immunoglobulin G (IgG) antibodies were assessed via enzyme-linked immunosorbent assay. We computed the odds ratios (ORs) and 95% confidence intervals (CIs) through univariable and multivariable analyses, adjusting for potential confounders. RESULTS There were 33/90 (36.67% [95% CI 26.75 to 47.48]) anti-Toxocara IgG seropositive individuals identified among the AD cases and 21/91 (23.07% [95% CI 14.89 to 33.09]) among the healthy controls. In univariable analysis, a significant association was identified between anti-Toxocara IgG seropositivity and AD (OR 1.93 [95% CI 1.01 to 3.69], p<0.001). Moreover, the association remained significant (OR 2.18 [95% CI 1.05 to 4.49], p<0.001) in multivariable analysis after adjustment for covariates. There was no association between anti-Toxocara IgG seropositivity and the severity of AD (OR 0.75 [95% CI 0.21 to 2.61], p=0.47). CONCLUSIONS Our findings indicated that Toxocara exposure/infection could be a potential risk factor for development of AD. To better understand a real causality between Toxocara exposure/infection and AD and related dementias, follow-up designed and adequately powered studies are needed.
Collapse
Affiliation(s)
- Ali Alizadeh Khatir
- Mobility Impairment Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
| | - Fariborz Mousavi
- Infectious Diseases and Tropical Medicine Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
| | - Mahdi Sepidarkish
- Department of Biostatistics and Epidemiology, School of Public Health, Babol University of Medical Sciences, Babol, Iran
| | - Mahdi Arshadi
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Delaram Arjmandi
- Infectious Diseases and Tropical Medicine Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
| | - Maryam Aldaghi
- Infectious Diseases and Tropical Medicine Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
| | - Ali Rostami
- Infectious Diseases and Tropical Medicine Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
| |
Collapse
|
2
|
Erickson LD, Hedges D, Stone A, Brown BL, Embley B, Gale SD. Association between toxocariasis seropositivity and serointensity and cognitive function in older U.S. adults. Folia Parasitol (Praha) 2022; 69. [DOI: 10.14411/fp.2022.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 03/12/2022] [Indexed: 11/19/2022]
|
3
|
Gale SD, Hedges DW. Neurocognitive and neuropsychiatric effects of toxocariasis. ADVANCES IN PARASITOLOGY 2020; 109:261-272. [PMID: 32381201 DOI: 10.1016/bs.apar.2020.01.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Caused by the neuroinvasive nematodes Toxocara canis and Toxocara cati, human toxocariasis has a worldwide distribution with seroprevalence in humans associated with low socioeconomic status and low educational attainment. Third-stage Toxocara larvae can invade human tissues, including the brain and spine, where they can result in encephalitis, meningitis, and inflammation. Toxocara infection in animal models has been associated with cognitive and behavioural changes. In humans, preliminary cross-sectional research suggests that Toxocara seropositivity is associated with worse cognitive function in children and adults. Additional preliminary cross-sectional findings suggest associations between Toxocara seropositivity and neuropsychiatric function, including schizophrenia and neurologic conditions such as epilepsy. Given the widespread distribution of human toxocariasis and early evidence suggesting that it can be associated with cognitive and neuropsychiatric function in humans, additional research regarding the effects of toxocariasis on the human brain is required.
Collapse
Affiliation(s)
- Shawn D Gale
- Department of Psychology, Brigham Young University, Provo, UT, United States; The Neuroscience Centre, Brigham Young University, Provo, UT, United States.
| | - Dawson W Hedges
- Department of Psychology, Brigham Young University, Provo, UT, United States; The Neuroscience Centre, Brigham Young University, Provo, UT, United States
| |
Collapse
|
4
|
Bradbury RS, Hobbs CV. Toxocara seroprevalence in the USA and its impact for individuals and society. ADVANCES IN PARASITOLOGY 2020; 109:317-339. [PMID: 32381205 DOI: 10.1016/bs.apar.2020.01.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Toxocara species are intestinal helminths of dogs and cats, the larval stages of which may infect humans and cause severe neural, ocular and visceral larva migrans disease. Such cases of severe overt disease represent only a small fraction of the of the US population who have been exposed and infected with Toxocara, subsequently developing IgG antibodies to the larvae. The true impact of exposure to Toxocara in this large group of Americans remains uncertain. Toxocara antibody positivity is associated with poverty, but other specific risk factors have been identified, including sex, age, rural residence, region of residence, race and exposure to pets. This seropositive status has also been associated with several childhood diseases, including asthma and epilepsy, increased serum lead levels, and poor neurocognitive function. Three large-scale NHANES studies have provided comprehensive datasets, while several smaller studies have explored specific disease associations. Each seroprevalence study must be interpreted in consideration of the sensitivity and specificity of the individual serological methods employed. This chapter summarizes all historical Toxocara prevalence data from dogs, cats and soil in the United States. It then carefully examines all previous human Toxocara seroprevalence surveys performed in the United States. Data from these surveys is assimilated, compared and discussed to determine the validity of findings and to accurately identify risk factors for Toxocara seropositivity. The validity of associations of exposure to Toxocara larvae and childhood diseases such as asthma and epilepsy and effects neurocognitive function within the American context are also explored.
Collapse
Affiliation(s)
- Richard S Bradbury
- School of Health and Life Sciences, Federation University Australia, Berwick, VIC, Australia.
| | - Charlotte V Hobbs
- Children's of Mississippi, University of Mississippi Medical Center, Jackson, MS, United States
| |
Collapse
|
5
|
Fan CK. Pathogenesis of cerebral toxocariasis and neurodegenerative diseases. ADVANCES IN PARASITOLOGY 2020; 109:233-259. [PMID: 32381200 DOI: 10.1016/bs.apar.2020.01.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Toxocara canis belongs to one of zoonotic parasites that commonly infects canines worldwide, and its eggs in host faeces may contaminate the food, water, soil and their fur as well as the larvae entrapped in the granuloma can infect paratenic hosts including mice and humans. Survivability of T. canis embryonated eggs under moist, cool conditions may be as long as 2-4 years or more. In paratenic hosts such as mice and humans, T. canis L3 larvae neither moult, grow, nor replicate and will wander through a number of internal organs in humans so as to cause Th2-dominant pathology in various internal organs as leading to neurotoxocariasis (NT), ocular toxocariasis (OT), or visceral larva migrans (VLM). Although the systemic immune response to T. canis has been widely reported, the immune response in the brain has received little attention. Differential cytokine expression and other brain injury-associated biomarkers or neurodegeneration-associated factors have been observed in infected versus uninfected outbred and inbred mice. Preliminary data have also suggested a possible link between significant memory impairment and cytokine production associated with T. canis infection in the hippocampus which has been long recognised as being responsible for learning and memory functions. Notably, it remains an enigma concerning cerebral invasion by T. canis larvae rarely induces a recognisable neurological syndrome or its involvement in neuropathological disorders in humans. Exploration of the relationship between host and parasite in the brain may elucidate the cryptic symptoms of human cerebral toxocariasis, with patients presenting with mental retardation, epilepsy, neurodegeneration and other central nervous system (CNS) disorders.
Collapse
Affiliation(s)
- Chia-Kwung Fan
- Department of Molecular Parasitology and Tropical Diseases, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Research Center of International Tropical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Tropical Medicine Division, International PhD Program in Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
| |
Collapse
|
6
|
Silva MB, Amor AL, Santos LN, Galvão AA, Oviedo Vera AV, Silva ES, Barbosa CG, Gonçalves MS, Cooper PJ, Figueiredo CA, Ribeiro RDC, Alcântara-Neves NM. Risk factors for Toxocara spp. seroprevalence and its association with atopy and asthma phenotypes in school-age children in a small town and semi-rural areas of Northeast Brazil. Acta Trop 2017; 174:158-164. [PMID: 27080332 DOI: 10.1016/j.actatropica.2016.04.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2015] [Revised: 04/04/2016] [Accepted: 04/08/2016] [Indexed: 10/22/2022]
Abstract
Toxocara canis, Toxocara cati, are roundworms that live in the intestines of dogs and cats, respectively, and are predominantly agents of human toxocariasis. Studies have suggested that Toxocara spp. seroprevalence increases levels of total and aeroallergen-specific IgE (sIgE), asthma prevalence and asthma morbidity. Nevertheless, other work reported a negative association between Toxocara spp. seropositivity with skin hypersensititity and a positive association with sIgE. The objective of the present study was to evaluate risk factors for acquiring Toxocara spp. infection and to investigate possible significant association between its seroprevalence with atopy and asthma. Students from elementary schools, residents in a small town and its surroundings of Northeast Brazil, underwent blood sampling to measure levels of anti-Toxocara spp. IgG, peripheral blood eosinophils, and specific IgE to aeroallergens. We used univariable and multivariable logistic regression analyses to assess possible risk factors for Toxocara spp. seropositivity and its association with atopy, wheeze/asthma with asthma phenotypes, in a sample of 791 elementary school children aged 6-13 years. Toxocara spp. seroprevalence reached 63.6%; 49.9% had sIgE; 7.2% and 3.3% had atopic wheeze/asthma and non-atopic wheeze/asthma respectively. Risk factors associated with Toxocara spp. seropositivity were: contact with dogs (adj. OR 2.33; 95% CI=1.70-3.19) and cats (adj. OR 3.09; 95% CI=2.10-4.55), and male sex (adj. OR 2.21; 95% CI=1.62-3.02). The presence of anti-Toxocara IgG was statistically associated with blood eosinophils >4% and >10% (adj. OR 1.84; 95% CI=1.33-2.55 and adj. OR 2.07; 95% CI=1.45-2.97, respectively), and atopy (adj. OR 2.00; 95% CI=1.49-2.68), but it was not associated with wheeze/asthma. Concluding, the results obtained in this study showing the association of Toxocara spp. seroprevalence with sIgE may suggest a possible immunological cross-reactivity between IgE epitopes from Toxocara spp. and aeroallergens.
Collapse
|
7
|
Janecek E, Waindok P, Bankstahl M, Strube C. Abnormal neurobehaviour and impaired memory function as a consequence of Toxocara canis- as well as Toxocara cati-induced neurotoxocarosis. PLoS Negl Trop Dis 2017; 11:e0005594. [PMID: 28481889 PMCID: PMC5436879 DOI: 10.1371/journal.pntd.0005594] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 05/18/2017] [Accepted: 04/24/2017] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Neuroinvasive larvae of the worldwide occurring zoonotic roundworms Toxocara canis and T. cati may induce neurotoxocarosis (NT) in humans, provoking a variety of symptoms including cognitive deficits as well as neurological dysfunctions. An association with neuropsychological disorders has been discussed. Similar symptoms have been described in T. canis-infected mice, whereas data on T. cati-induced NT are rare. Therefore, it was aimed to obtain insights into the impact on neurobehaviour as well as progression of neurological symptoms and behavioural alterations during the course of NT directly comparing T. canis- and T. cati-infected mice as models for human NT. METHODOLOGY/PRINCIPAL FINDINGS C57BL/6 mice were orally infected with 2000 embryonated T. canis or T. cati eggs, respectively, the control group received tap water. Mice were screened weekly for neurobehavioural alterations and memory function starting one day prior infection until 97 days post infection (pi; T. canis-infection) and day 118 pi (T. cati-infection, uninfected control). Mostly motoric and neurological parameters were affected in T. canis-infected mice starting day 20 pi with severe progression accompanied by stereotypical circling. In contrast, T. cati-infected mice mostly showed reduced response to sudden sound stimulus (indicator for excitability) and flight behaviour starting day 6 pi. Interestingly, enhanced grooming behaviour was observed exclusively in T. cati-infected mice, indicating a possible role of neurotransmitter dysregulation. Reduced exploratory behaviour and memory impairment was observed in both infection groups with delayed onset and less severe progression in T. cati- compared to T. canis-infected mice. CONCLUSIONS/SIGNIFICANCE Results highlight the need to consider T. cati beside T. canis as causative agent of human NT. Findings provide valuable hints towards differences in key regulatory mechanisms during T. canis- and T. cati-induced NT, contributing to a comprehensive picture and consequently a broader understanding of NT, which will aid in developing strategies towards prevention in addition to novel diagnostic and therapeutic approaches.
Collapse
Affiliation(s)
- Elisabeth Janecek
- Institute for Parasitology, Centre for Infection Medicine, University of Veterinary Medicine Hannover, Hanover, Germany
| | - Patrick Waindok
- Institute for Parasitology, Centre for Infection Medicine, University of Veterinary Medicine Hannover, Hanover, Germany
| | - Marion Bankstahl
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Hanover, Germany
- Center for Systems Neuroscience, Hanover, Germany
| | - Christina Strube
- Institute for Parasitology, Centre for Infection Medicine, University of Veterinary Medicine Hannover, Hanover, Germany
| |
Collapse
|
8
|
He X, Lv MN, Liu GH, Lin RQ. Genetic analysis of Toxocara cati (Nematoda: Ascarididae) from Guangdong province, subtropical China. Mitochondrial DNA A DNA Mapp Seq Anal 2017; 29:132-135. [PMID: 28141958 DOI: 10.1080/24701394.2016.1258404] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Toxocara cati (cat roundworm) is a common parasitic nematode that infects humans and other hosts, causing toxocariasis. Although its significance as a pathogen, the epidemiology, genetics and biology of T. cati remain poorly understand in China. In the present study, genetic variation in mitochondrial (mt) cytochrome c oxidase subunit 1 (cox1) gene and internal transcribed spacer (ITS) of rDNA region among T. cati in Guangdong province, subtropical China was examined. A portion of the cox1 (pcox1) and the complete ITS (ITS1 + 5.8S rDNA + ITS2) were amplified separately from individual worms by polymerase chain reaction (PCR) and amplicons were then subjected to sequencing from both directions. The length of the sequences of pcox1, ITS-1, and ITS-2 were 308 bp, 462 bp, and 335 bp, respectively. The intra-specific sequence variations within T. cati were 0-3.6% for pcox1, 0-2.4% for ITS-1, and 0-2.7% for ITS-2. However, the inter-specific sequence differences were significantly higher, being 8.6%, 10.7%, and 11.3% for pcox1, ITS-1, and ITS-2, respectively. Phylogenetic analyses based on the pcox1 sequences indicated that all the isolates in Guangdong province were in genus Toxocara, which confirmed that these parasites represent T. cati. The molecular approach employed provides a powerful tool for elucidating the epidemiology, genetics, and biology of zoonotic T. cati in China and elsewhere.
Collapse
Affiliation(s)
- Xi He
- a College of Veterinary Medicine , South China Agricultural University , Guangzhou , Guangdong Province , PR China.,b Key Laboratory of Zoonosis Prevention and Control of Guangdong Province , Guangzhou , Guangdong Province , PR China
| | - Meng-Na Lv
- a College of Veterinary Medicine , South China Agricultural University , Guangzhou , Guangdong Province , PR China.,b Key Laboratory of Zoonosis Prevention and Control of Guangdong Province , Guangzhou , Guangdong Province , PR China
| | - Guo-Hua Liu
- c College of Veterinary Medicine , Hunan Agricultural University , Changsha , Hunan Province , PR China
| | - Rui-Qing Lin
- a College of Veterinary Medicine , South China Agricultural University , Guangzhou , Guangdong Province , PR China.,b Key Laboratory of Zoonosis Prevention and Control of Guangdong Province , Guangzhou , Guangdong Province , PR China
| |
Collapse
|
9
|
Infectious disease burden and cognitive function in young to middle-aged adults. Brain Behav Immun 2016; 52:161-168. [PMID: 26598104 DOI: 10.1016/j.bbi.2015.10.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 10/23/2015] [Accepted: 10/23/2015] [Indexed: 11/20/2022] Open
Abstract
Prior research has suggested an association between exposure to infectious disease and neurocognitive function in humans. While most of these studies have explored individual viral, bacterial, and even parasitic sources of infection, few have considered the potential neurocognitive burden associated with multiple infections. In this study, we utilized publically available data from a large dataset produced by the Centers for Disease Control and Prevention that included measures of neurocognitive function, sociodemographic variables, and serum antibody data for several infectious diseases. Specifically, immunoglobulin G antibodies for toxocariasis, toxoplasmosis, hepatitis A, hepatitis B, and hepatitis C, cytomegalovirus, and herpes 1 and 2 were available in 5662 subjects. We calculated an overall index of infectious-disease burden to determine if an aggregate measure of exposure to infectious disease would be associated with neurocognitive function in adults aged 20-59 years. The index predicted processing speed and learning and memory but not reaction time after controlling for age, sex, race-ethnicity, immigration status, education, and the poverty-to-income ratio. Interactions between the infectious-disease index and some sociodemographic variables were also associated with neurocognitive function. In summary, an index aggregating exposure to several infectious diseases was associated with neurocognitive function in young- to middle-aged adults.
Collapse
|
10
|
Abstract
Toxocara canis and T. cati are highly prevalent nematode infections of the intestines of dogs and cats. In paratenic hosts, larvae do not mature in the intestine but instead migrate through the somatic tissues and organs of the body. The presence of these migrating larvae can contribute to pathology. Toxocara larvae can invade the brains of humans, and while case descriptions of cerebral toxocariasis are historically rare, improved diagnosis and greater awareness have contributed to increased detection. Despite this, cerebral or neurological toxocariasis (NT) remains a poorly understood phenomenon. Furthermore, our understanding of cognitive deficits due to toxocariasis in human populations remains particularly deficient. Recent data describe an enhanced expression of biomarkers associated with brain injury, such as GFAP, AβPP, transforming growth factor β1 (TGF-β1), NF-L, S100B, tTG, and p-tau, in mice receiving even low doses of Toxocara ova. Finally, this review outlines a hypothesis to explore the relationship between the presence of T. canis larvae in the brain and the progression of Alzheimer's disease (AD) due to enhanced AD-associated neurodegenerative biomarker expression.
Collapse
|
11
|
Small-area estimation of the probability of toxocariasis in New York City based on sociodemographic neighborhood composition. PLoS One 2014; 9:e99303. [PMID: 24918785 PMCID: PMC4053403 DOI: 10.1371/journal.pone.0099303] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 05/13/2014] [Indexed: 11/19/2022] Open
Abstract
Toxocariasis is increasingly recognized as an important neglected infection of poverty (NIP) in developed countries, and may constitute the most important NIP in the United States (US) given its association with chronic sequelae such as asthma and poor cognitive development. Its potential public health burden notwithstanding, toxocariasis surveillance is minimal throughout the US and so the true burden of disease remains uncertain in many areas. The Third National Health and Nutrition Examination Survey conducted a representative serologic survey of toxocariasis to estimate the prevalence of infection in diverse US subpopulations across different regions of the country. Using the NHANES III surveillance data, the current study applied the predicted probabilities of toxocariasis to the sociodemographic composition of New York census tracts to estimate the local probability of infection across the city. The predicted probability of toxocariasis ranged from 6% among US-born Latino women with a university education to 57% among immigrant men with less than a high school education. The predicted probability of toxocariasis exhibited marked spatial variation across the city, with particularly high infection probabilities in large sections of Queens, and smaller, more concentrated areas of Brooklyn and northern Manhattan. This investigation is the first attempt at small-area estimation of the probability surface of toxocariasis in a major US city. While this study does not define toxocariasis risk directly, it does provide a much needed tool to aid the development of toxocariasis surveillance in New York City.
Collapse
|
12
|
Liao CW, Sukati H, D'Lamini P, Chou CM, Liu YH, Huang YC, Chung MH, Mtsetfwa JS, Jonato J, Chiu WT, Chang PWS, Du WY, Chan HC, Chu TB, Cheng HC, Su WW, Tu CC, Cheng CY, Fan CK. Seroprevalence ofToxocaracanisinfection among children in Swaziland, southern Africa. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2013; 104:73-80. [DOI: 10.1179/136485910x12607012373795] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
|
13
|
Rubinsky-Elefant G, Hirata CE, Yamamoto JH, Ferreira MU. Human toxocariasis: diagnosis, worldwide seroprevalences and clinical expression of the systemic and ocular forms. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2013; 104:3-23. [DOI: 10.1179/136485910x12607012373957] [Citation(s) in RCA: 258] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
|
14
|
Abstract
AbstractA survey of intestinal parasites in dogs was carried out in a rural region around Cantanhede, in northern Portugal, where 301 dog faecal samples were collected from small-ruminant farms. Saturated salt flotation and formol–ether sedimentation techniques were used. An enquiry was conducted in 234 farms and a risk factor evaluation for zoonotic helminths was determined among the 195 farmers who owned dogs. The overall parasite prevalence in faecal samples of dogs was 58.8%, with specific prevalences for Ancylostomidae being 40.9% followed by species of Trichuris (29.9%), Toxocara (8%), Isospora (4%), Capillaria (0.7%) and Spirometra (0.3%). Taeniidae eggs were present in five samples (1.7%) which were analysed with the polymerase chain reaction (PCR) technique and revealed to be from Taenia sp., and not Echinococcusgranulosus. This rural region has a traditional small-farm system, in which farm products are mainly for in-house consumption and home slaughtering is a current practice (57%). Analysis showed home slaughtering to be a statistically significant risk factor for the presence of Ancylostomidae (P= 0.007) and Toxocara sp. (P= 0.049). Owning cattle was found to be a significant risk factor for Taenia sp. (P= 0.031).
Collapse
|
15
|
|
16
|
Reduced cognitive function in children with toxocariasis in a nationally representative sample of the United States. Int J Parasitol 2012; 42:1159-63. [DOI: 10.1016/j.ijpara.2012.10.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 10/03/2012] [Accepted: 10/05/2012] [Indexed: 10/27/2022]
|
17
|
Toxocara infection in the United States: the relevance of poverty, geography and demography as risk factors, and implications for estimating county prevalence. Int J Public Health 2010; 56:15-24. [DOI: 10.1007/s00038-010-0143-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Revised: 03/03/2010] [Accepted: 03/26/2010] [Indexed: 10/19/2022] Open
|
18
|
Developmental age, physical fitness andToxocaraseroprevalence amongst lower-secondary students living in rural areas contaminated withToxocaraeggs. Parasitology 2009; 137:53-63. [DOI: 10.1017/s0031182009990874] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
SUMMARYScarce and inconclusive information on general biological impact ofToxocarainvasion on paratenic hosts, and people in particular, has led us to undertake a comprehensive study of the problem. The study has been conducted in a rural environment, which is considered a toxocarosis risk factor. In total 200 soil samples have been screened forToxocaraeggs by flotation, of which 14·5% were positive. Backyards close to households were most heavily contaminated with infectious eggs – 21·7% of positive samples. ELISA serological tests performed on 242 lower-secondary students found 14·5% of the studied population to be definitely positive – 16·5% of boys and 12·8% of girls, respectively. The odds of being infected withToxocarawere 2 times (CI: 1·15–3·85) more likely for individuals who owned a cat than those who did not own a cat. Strong significant correlation between seropositivity and the presence of a dog in a household was found with boys. The level of developmental age was significantly higher in seropositive than in seronegative students. No significant correlation has been observed between the motor abilities and seropositivity of students. Seropositive boys had significantly lower end-of-year grades than their seronegative counterparts.
Collapse
|
19
|
Hotez PJ, Wilkins PP. Toxocariasis: America's most common neglected infection of poverty and a helminthiasis of global importance? PLoS Negl Trop Dis 2009; 3:e400. [PMID: 19333373 PMCID: PMC2658740 DOI: 10.1371/journal.pntd.0000400] [Citation(s) in RCA: 189] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- Peter J. Hotez
- Department of Microbiology, Immunology, and Tropical Medicine, The George Washington University, Washington, D.C., United States of America
- Sabin Vaccine Institute, Washington, D.C., United States of America
- * E-mail: or (PJH); (PPW)
| | - Patricia P. Wilkins
- Division of Parasitic Diseases, National Center for Zoonotic, Vector-Borne and Enteric Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- * E-mail: or (PJH); (PPW)
| |
Collapse
|
20
|
Alba-Hurtado F, Muñoz-Guzmán MA, Valdivia-Anda G, Tórtora JL, Ortega-Pierres MG. Toxocara canis: larval migration dynamics, detection of antibody reactivity to larval excretory-secretory antigens and clinical findings during experimental infection of gerbils (Meriones unguiculatus). Exp Parasitol 2009; 122:1-5. [PMID: 19545524 DOI: 10.1016/j.exppara.2009.01.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Revised: 01/07/2009] [Accepted: 01/14/2009] [Indexed: 12/01/2022]
Abstract
In this study, Mongolian gerbils were used to analyse features of Toxocara infection that included larval migration, humoral immune responses to Toxocara canis excretory-secretory antigens (TES) and aspects of host physiology. At day 10 post-infection (p.i.) most larvae were in the intestine and the lungs while later the total number of larvae was higher in the carcass tissue; the number of larvae per gram of tissue was lower elsewhere other than in the brain. Infected animals showed several neurological abnormalities, an early increase in leukocyte and neutrophil levels, two peaks of peripheral eosinophilia (5 and 40 d.p.i.) and high antibody levels against TES in the circulation and in the vitreous humor. A sequential recognition of eight T.canis larval antigens with MW from 24 to 200 kDa was detected by Western blot. The results obtained in this study further support the use of gerbils as an experimental model for systemic, ocular and cerebral toxocariasis.
Collapse
Affiliation(s)
- F Alba-Hurtado
- Departamento de Ciencias Biológicas, Facultad de Estudios Superiores Cuautitlán, Universidad Nacional Autónoma de México, 54714 Cuautitlán, Mexico.
| | | | | | | | | |
Collapse
|
21
|
Abstract
In the United States, there is a largely hidden burden of diseases caused by a group of chronic and debilitating parasitic, bacterial, and congenital infections known as the neglected infections of poverty. Like their neglected tropical disease counterparts in developing countries, the neglected infections of poverty in the US disproportionately affect impoverished and under-represented minority populations. The major neglected infections include the helminth infections, toxocariasis, strongyloidiasis, ascariasis, and cysticercosis; the intestinal protozoan infection trichomoniasis; some zoonotic bacterial infections, including leptospirosis; the vector-borne infections Chagas disease, leishmaniasis, trench fever, and dengue fever; and the congenital infections cytomegalovirus (CMV), toxoplasmosis, and syphilis. These diseases occur predominantly in people of color living in the Mississippi Delta and elsewhere in the American South, in disadvantaged urban areas, and in the US-Mexico borderlands, as well as in certain immigrant populations and disadvantaged white populations living in Appalachia. Preliminary disease burden estimates of the neglected infections of poverty indicate that tens of thousands, or in some cases, hundreds of thousands of poor Americans harbor these chronic infections, which represent some of the greatest health disparities in the United States. Specific policy recommendations include active surveillance (including newborn screening) to ascertain accurate population-based estimates of disease burden; epidemiological studies to determine the extent of autochthonous transmission of Chagas disease and other infections; mass or targeted treatments; vector control; and research and development for new control tools including improved diagnostics and accelerated development of a vaccine to prevent congenital CMV infection and congenital toxoplasmosis.
Collapse
Affiliation(s)
- Peter J Hotez
- Department of Microbiology, Immunology, and Tropical Medicine, The George Washington University and Sabin Vaccine Institute, Washington, D.C., USA.
| |
Collapse
|
22
|
Fan CK, Liao CW, Kao TC, Li MH, Du WY, Su KE. Sero-epidemiology of Toxocara canis infection among aboriginal schoolchildren in the mountainous areas of north-eastern Taiwan. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2005; 99:593-600. [PMID: 16156973 DOI: 10.1179/136485905x51373] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A sero-epidemiological study of Toxocara canis infection was conducted among Atayal schoolchildren (aged 7-12 years) residing in the mountainous areas of north-eastern Taiwan. The 73 children investigated were each checked for anti-Toxocara IgG, in ELISA based on the larval excretory-secretory antigens of T. canis larvae. A short, self-administered questionnaire was then used to collect relevant information from each subject, including data on the keeping of dogs, playing in soil, eating raw vegetables, and whether the subjects normally washed their hands before eating. Once the seropositive children had been identified, odds ratios (OR), with their corresponding 95% confidence intervals (CI) and P-values, were calculated for each potential risk factor. When diluted 1:64, sera from 42 (57.5%) of the children gave a positive result in the ELISA, indicating that these 42 children were seropositive for T. canis infection. Seropositivity did not appear to be associated with the age or gender of the subject, the eating of raw vegetables, or the regular failure to wash hands prior to a meal. Compared with the other subjects, however, those who admitted living in a household where dogs were kept (OR = 3.79; CI = 1.23-11.69; P = 0.02) or playing in soil (OR = 3.00; CI = 1.10-8.16; P = 0.03) appeared at increased risk of seropositivity.
Collapse
Affiliation(s)
- C-K Fan
- No. 250, Wu-Hsing Street, Department of Parasitology, College of Medicine, Taipei Medical University, Taiwan.
| | | | | | | | | | | |
Collapse
|
23
|
Fan CK, Hung CC, Du WY, Liao CW, Su KE. Seroepidemiology of Toxocara canis infection among mountain aboriginal schoolchildren living in contaminated districts in eastern Taiwan. Trop Med Int Health 2004; 9:1312-8. [PMID: 15598263 DOI: 10.1111/j.1365-3156.2004.01332.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We conducted a seroepidemiological study of Toxocara canis infection among mountain aboriginal schoolchildren aged 7-12 years living in contaminated districts in eastern Taiwan. To detect sera IgG (> or =1:64) we used a T. canis larval excretory-secretory antigen-based enzyme-linked immunosorbent assay. A short questionnaire elicited information on the practices of raising dogs, playing with soil, eating raw vegetables, or whether the child normally washed his/her hands before eating. The overall seroprevalence was quite high, reaching 76.6% (252/329). Neither age nor gender seemed to be important factors related to a positive serology. Aboriginal schoolchildren who raised dogs (OR=1.83, 95% CI: 1.04-3.19, P=0.03), or played with soil (OR=2.52, 95% CI: 1.49-4.25, P <0.001) seemed to be more susceptible to T. canis infection than those who did not. Children who habitually washed their hands before eating (OR=0.57, 95% CI: 0.33-0.97, P=0.04) had a lower chance of acquiring T. canis infection than those who did not.
Collapse
Affiliation(s)
- Chia-Kwung Fan
- Department of Parasitology, College of Medicine, Taipei Medical University, Taiwan.
| | | | | | | | | |
Collapse
|
24
|
Söndergaard HP, Theorell T. A putative role for Toxocara species in the aetiology of multiple sclerosis. Med Hypotheses 2004; 63:59-61. [PMID: 15193348 DOI: 10.1016/j.mehy.2004.02.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2003] [Accepted: 02/02/2004] [Indexed: 11/29/2022]
Abstract
Multiple sclerosis (MS) is a disease of unknown aetiology. The finding of monoclonal antibodies in MS has been attributed to various infectious agents. Nematodes, such as Toxocara species have not been explored as possible aetiologic agents of MS. Some epidemiological studies have found an association between exposure to stress and household pets prior to the diagnosis of MS. In a case known to the authors, slight malaise and eosinophilia in peripheral blood preceded the diagnosis of MS by one year in a middle-aged man who lived in rural surroundings with cats in the household. The ubiquitary parasite Toxocara catis or canis is prevalent and serum antibodies are found regularly in populations examined. It is able to develop into the larval stage in human beings. The hypothesis presented here is that MS could be initiated by such infections in previously unexposed subjects under conditions of long-term stress.
Collapse
Affiliation(s)
- Hans Peter Söndergaard
- Swedish National Institute for Psychosocial Factors and Health (IPM) and Department of Public Health Sciences, Karolinska Institute, P.O. Box 230, 171 77 Stockholm, Sweden.
| | | |
Collapse
|
25
|
Sharghi N, Schantz P, Hotez PJ. Toxocariasis: An occult cause of childhood neuropsychological deficits and asthma? ACTA ACUST UNITED AC 2000. [DOI: 10.1053/spid.2000.9640] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
26
|
Alba-Hurtado F, Tórtora PJ, Tsutsumi V, Ortega-Pierres MG. Histopathological investigation of experimental ocular toxocariasis in gerbils. Int J Parasitol 2000; 30:143-7. [PMID: 10704597 DOI: 10.1016/s0020-7519(99)00173-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Male gerbils were inoculated intragastrically with embryonated Toxocara canis eggs. They were euthanised, and their eyes were excised at different days p.i. to identify the number of larvae as well as lesions resulting in these organs. In most animals, larvae were detected from day 5 to day 60 p.i. (end of the study). From days 10 to 20 p.i., larvae and haemorrhage were observed in the choroid and in the ciliary process. At days 30 and 40 p.i., some eyes had larvae surrounded by an infiltrate of neutrophils, oedema, haemorrhages and tissue damage in the retina or the ciliary process. On day 60 p.i., there were granulomatous lesions in the retina. This study provides a model for the study of ocular toxocariasis.
Collapse
Affiliation(s)
- F Alba-Hurtado
- Department of Biological Science and Postgraduate Program on Microbiology, Facultad de Estudios Superiores Cuautitlán, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | | | | | | |
Collapse
|