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Infectious Diseases of Poverty Jun 2018Toxocariasis is a neglected parasitic zoonosis that afflicts millions of the pediatric and adolescent populations worldwide, especially in impoverished communities. This... (Review)
Review
BACKGROUND
Toxocariasis is a neglected parasitic zoonosis that afflicts millions of the pediatric and adolescent populations worldwide, especially in impoverished communities. This disease is caused by infection with the larvae of Toxocara canis and T. cati, the most ubiquitous intestinal nematode parasite in dogs and cats, respectively. In this article, recent advances in the epidemiology, clinical presentation, diagnosis and pharmacotherapies that have been used in the treatment of toxocariasis are reviewed.
MAIN TEXT
Over the past two decades, we have come far in our understanding of the biology and epidemiology of toxocariasis. However, lack of laboratory infrastructure in some countries, lack of uniform case definitions and limited surveillance infrastructure are some of the challenges that hindered the estimation of global disease burden. Toxocariasis encompasses four clinical forms: visceral, ocular, covert and neural. Incorrect or misdiagnosis of any of these disabling conditions can result in severe health consequences and considerable medical care spending. Fortunately, multiple diagnostic modalities are available, which if effectively used together with the administration of appropriate pharmacologic therapies, can minimize any unnecessary patient morbidity.
CONCLUSIONS
Although progress has been made in the management of toxocariasis patients, there remains much work to be done. Implementation of new technologies and better understanding of the pathogenesis of toxocariasis can identify new diagnostic biomarkers, which may help in increasing diagnostic accuracy. Also, further clinical research breakthroughs are needed to develop better ways to effectively control and prevent this serious disease.
Topics: Animals; Cats; Dogs; Humans; Neglected Diseases; Public Health; Toxocara; Toxocara canis; Toxocariasis; Zoonoses
PubMed: 29895324
DOI: 10.1186/s40249-018-0437-0 -
Revista Do Instituto de Medicina... 2007Infection of humans with embryonated eggs of Toxocara canis (larva migrans) remains asymptomatic, or results in covert or common toxocarosis, visceral larva migrans... (Review)
Review
Infection of humans with embryonated eggs of Toxocara canis (larva migrans) remains asymptomatic, or results in covert or common toxocarosis, visceral larva migrans syndrome, or ophthalmologic and neurologic impairment. Though neurological manifestations of Toxocara canis larvae are rare, toxocarosis remains an important differential diagnosis of various neurological disorders. Manifestations of the central nervous system are dementia, meningo-encephalitis, myelitis, cerebral vasculitis, epilepsy, or optic neuritis. Manifestations of the peripheral nervous system comprise radiculitis, affection of cranial nerves, or musculo-skeletal involvement. If toxocarosis is neglected, ignored, or refused as a differential of these abnormalities, it may be easily overlooked for years. Early recognition and treatment of the infection is, however, of paramount importance since it reduces morbidity and mortality and the risk of secondary superinfection. Like the visceral manifestations, neurological manifestations of toxocarosis are treated by benzimidazole components, most frequently albendazole, corticosteroids, or diethylcarbamazine. If detected and treated early, the prognosis of neurological manifestations of toxocarosis is favourable.
Topics: Animals; Cats; Central Nervous System Helminthiasis; Diagnosis, Differential; Dogs; Humans; Peripheral Nervous System Diseases; Toxocara canis; Toxocariasis
PubMed: 18026633
DOI: 10.1590/s0036-46652007000500002 -
Microorganisms Jan 2022and are globally occurring zoonotic roundworms of dogs and cats. Migration and persistence of larvae in the central nervous system of paratenic hosts including humans...
and are globally occurring zoonotic roundworms of dogs and cats. Migration and persistence of larvae in the central nervous system of paratenic hosts including humans may cause clinical signs of neurotoxocarosis (NT). As pathomechanisms of NT and host responses against larvae are mostly unknown, whole-genome microarray transcription analysis was performed in cerebra and cerebella of experimentally infected C57Bl/6J mice as paratenic host model at days 14, 28, 70, 98, and 120 post-infection. Neuroinvasion of evoked 220 cerebral and 215 cerebellar differentially transcribed genes (DTGs), but no particular PANTHER (Protein ANalysis THrough Evolutionary Relationships) pathway was affected. In -infected mice, 1039 cerebral and 2073 cerebellar DTGs were identified. Statistically significant dysregulations occurred in various pathways, including cholesterol biosynthesis, apoptosis signaling, and the Slit/Robo mediated axon guidance as well as different pathways associated with the immune and defense response. Observed dysregulations of the cholesterol biosynthesis, as well as the Alzheimer disease-amyloid secretase pathway in conjunction with previous histopathological neurodegenerative findings, may promote the discussion of as a causative agent for dementia and/or Alzheimer's disease. Furthermore, results contribute to a deeper understanding of the largely unknown pathogenesis and host-parasite interactions during NT, and may provide the basis for prospective investigations evaluating pathogenic mechanisms or designing novel diagnostic and therapeutic approaches.
PubMed: 35056627
DOI: 10.3390/microorganisms10010177 -
Parasite Epidemiology and Control Feb 2022is a helminth zoonosis that is estimated to infect more than 100 million dogs and 1 billion people, mostly in the tropics. Humans can be infected by accidentally...
is a helminth zoonosis that is estimated to infect more than 100 million dogs and 1 billion people, mostly in the tropics. Humans can be infected by accidentally ingesting embryonated eggs from the environment or occasionally after ingesting L larvae from paratenic hosts. This study investigated the importance of vertical transmission and the role of puppies in the epidemiology of through the examination of fecal samples from dogs less than one year of age in Grenada, West Indies, a small island tropical developing country. Samples were stored at 4 °C or in 10% formalin until microscopic examination for helminth eggs or using a rapid antigen test for the presence of protozoan species. A knowledge, attitudes and practices study was completed among dog owners, physicians and veterinary students. Of 306 dogs less than one year of age, 147 (48%) were found to have eggs. Vertical transmission was indicated by the proportion of infected dogs increasing from 50% at two weeks of age (from in utero transmission) to 70% by 12 weeks (in utero and lactogenic transmission). After 12 weeks the positivity rate dropped rapidly with no dogs over 40 weeks of age being infected. As eggs were found in puppy feces at two weeks of age, initial treatment of puppies should begin earlier, at twelve days post-partum, than currently recommended to prevent shedding of eggs. Perhaps even more importantly, treatment of pregnant dogs, preventing vertical transmission, would have a major impact on the control of infection. Knowledge of . and other zoonotic helminths such as was found to be low among dog owners, physicians and veterinary students. None of the dog owners treated their dogs for helminths, all were unaware of the risk of zoonoses, and only 9% picked up dog feces. Efforts to prevent vertical transmission and to increase awareness and knowledge of these zoonoses could result in reducing their public health impact.
PubMed: 34917784
DOI: 10.1016/j.parepi.2021.e00232 -
Parasitology Jan 2022Human 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... (Review)
Review
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.
Topics: Animals; Brain; Dogs; Humans; Nervous System Diseases; Toxocara; Toxocara canis; Toxocariasis; Zoonoses
PubMed: 34694217
DOI: 10.1017/S0031182021001591 -
Frontiers in Cell and Developmental... 2021Bone marrow is the main hematopoietic organ that produces red blood cells, granulocytes, monocyte/macrophages, megakaryocytes, lymphocytes, and myeloid dendritic cells....
Bone marrow is the main hematopoietic organ that produces red blood cells, granulocytes, monocyte/macrophages, megakaryocytes, lymphocytes, and myeloid dendritic cells. Many of these cells play roles in the pathogenesis of infection, and understanding how infection alters the dynamics of transcription regulation in bone marrow is therefore critical for deciphering the global changes in the dog transcriptional signatures during infection. In this study, long non-coding RNA (lncRNA) and messenger RNA (mRNA) expression profiles in the bone marrow of Beagle dogs infected with were determined at 12 h post-infection (hpi), 24 hpi, 96 hpi, and 36 days post-infection (dpi). RNA-sequencing and bioinformatics analysis identified 1,098, 984, 1,120, and 1,305 differentially expressed lncRNAs (DElncRNAs), and 196, 253, 223, and 328 differentially expressed mRNAs (DEmRNAs) at 12 h, 24 h, 96 h, and 36 days after infection, respectively. We also identified 29, 36, 38, and 68 DEmRNAs potentially -regulated by 44, 44, 51, and 80 DElncRNAs at 12 hpi, 24 hpi, 96 hpi, and 36 dpi, respectively. To validate the sequencing findings, qRT-PCR was performed on 10 randomly selected transcripts. Many altered genes were involved in the differentiation of bone marrow cells. GO of DElncRNAs and GO and KEGG pathway analyses of DEmRNAs revealed alterations in several signaling pathways, including pathways involved in energy metabolism, amino acid biosynthesis and metabolism, Wnt signaling pathway, Huntington's disease, HIF-1 signaling pathway, cGMP-PKG signaling pathway, dilated cardiomyopathy, and adrenergic signaling in cardiomyocytes. These findings revealed that bone marrow of -infected dogs exhibits distinct lncRNA and mRNA expression patterns compared to healthy control dogs. Our data provide novel insights into interaction with the definitive host and shed light on the significance of the non-coding portion of the dog genome in the pathogenesis of toxocariasis.
PubMed: 34277631
DOI: 10.3389/fcell.2021.688128 -
International Journal For Parasitology.... Dec 2023species are cosmopolitan nematode parasites of companion, domestic and wild hosts. Of the 26 known species of only and are definitively zoonotic. The significance of... (Review)
Review
species are cosmopolitan nematode parasites of companion, domestic and wild hosts. Of the 26 known species of only and are definitively zoonotic. The significance of wild carnivores as definitive hosts of . and . respectively, has received far less attention compared to domestic dogs and cats. Complex environmental changes have promoted increasing contact between wildlife, domestic animals and humans that can enhance the risk of pathogen spillover. This review lists a total of 19 species of wild canid host that have been shown to act as definitive hosts for . and a total of 21 species of wild felid host. In general, the number of publications focusing on felid host species is fewer in number, reflecting the general paucity of data on . . The wild canids that have received the most attention in the published literature include the red fox (), the wolf (, and the golden jackal (). The wild felid species that has received the most attention in the published literature is the Eurasian lynx (). Some non-canid and non-felid hosts also act as definitive hosts of species. Certainly, red foxes would appear to be the most significant wild species in terms of their potential to transmit to domestic dogs and humans via environmental contamination. This can be explained by their increasing population densities, encroachment into urban areas and their dietary preferences for a wide range of potential paratenic hosts. However, a major challenge remains to assess the relative importance of wild hosts as contributors to environmental contamination with ova. Furthermore, one major constraint to our understanding of the significance of wildlife parasitism is a lack of access to samples, particularly from rare host species.
PubMed: 37964985
DOI: 10.1016/j.ijppaw.2023.10.008 -
Experimental and Therapeutic Medicine May 2021Human helminth zoonosis is one of the most encountered helminthiases worldwide. Representative diseases include and , which are common nematodes prevalent in dogs and... (Review)
Review
Human helminth zoonosis is one of the most encountered helminthiases worldwide. Representative diseases include and , which are common nematodes prevalent in dogs and cats. The infiltration of these roundworms in the human body through contaminated food or nematode eggs could lead to central nervous system injury as the roundworms can cross the blood-brain barrier leading to neurotoxocariasis. Among the neurological and neuropsychological disturbances produced by Toxocara infection, in humans, the most representative are meningitis, encephalitis, myelitis and cerebral vasculitis, but asymptomatic central nervous system infection is probably the most prevalent. The present review examines the clinical symptomatology of neurotoxocariasis in case reports in the literature in the last 7 decades (1950-2020). The available evidence was retrieved from PubMed and Medline electronic databases. The present review reports the most prevalent clinical symptomatology in the cases of detected and diagnosed Toxocara infection with neuroinvasion. Thus, the present review aims to raise the awareness of neurological cases of Toxocara infection with the potential to at least establish differential diagnosis of neurotoxocariasis.
PubMed: 33815594
DOI: 10.3892/etm.2021.9953