-
International Ophthalmology Jan 2022This review aims to summarize the current knowledge concerning the clinical features, diagnostic work-up and therapeutic approach of ocular toxoplasmosis focusing mainly... (Review)
Review
PURPOSE
This review aims to summarize the current knowledge concerning the clinical features, diagnostic work-up and therapeutic approach of ocular toxoplasmosis focusing mainly on the postnatally acquired form of the disease.
METHODS
A meticulous literature search was performed in the PubMed database. A supplementary search was made in Google Scholar to complete the collected items.
RESULTS
Ocular toxoplasmosis is one of the most frequent infectious etiologies of posterior uveitis. It typically presents with retinochoroiditis. Setting an accurate diagnosis depends to a considerable degree on detecting characteristic clinical characteristics. In addition to the evaluation of clinical features, the diagnosis of toxoplasmosis relies at a large degree on serologic testing. The detection of the parasite DNA in the aqueous or vitreous humor can provide evidence for a definitive diagnosis. The current mainstay for the treatment, if necessary, is the use of oral antibiotic with systemic corticosteroids. Recent evidence suggests other therapeutic approaches, such as intravitreal antibiotics can be used.
CONCLUSION
Recent developments in the diagnostic and therapeutic approach have contributed to preventing or limiting vision loss of patients suffering from ocular toxoplasmosis. Further studies are required to provide a better understanding of epidemiology, pathogenesis, diagnosis, and treatment with a significant impact on the management of this challenging clinical entity.
Topics: Chorioretinitis; Eye; Humans; Toxoplasma; Toxoplasmosis, Ocular; Uveitis, Posterior
PubMed: 34370174
DOI: 10.1007/s10792-021-01994-9 -
International Journal For Parasitology Feb 2021Toxoplasmosis is caused by Toxoplasma gondii, an apicomplexan parasite that is able to infect any nucleated cell in any warm-blooded animal. Toxoplasma gondii infects... (Review)
Review
Toxoplasmosis is caused by Toxoplasma gondii, an apicomplexan parasite that is able to infect any nucleated cell in any warm-blooded animal. Toxoplasma gondii infects around 2 billion people and, whilst only a small percentage of infected people will suffer serious disease, the prevalence of the parasite makes it one of the most damaging zoonotic diseases in the world. Toxoplasmosis is a disease with multiple manifestations: it can cause a fatal encephalitis in immunosuppressed people; if first contracted during pregnancy, it can cause miscarriage or congenital defects in the neonate; and it can cause serious ocular disease, even in immunocompetent people. The disease has a complex epidemiology, being transmitted by ingestion of oocysts that are shed in the faeces of definitive feline hosts and contaminate water, soil and crops, or by consumption of intracellular cysts in undercooked meat from intermediate hosts. In this review we examine current and future approaches to control toxoplasmosis, which encompass a variety of measures that target different components of the life cycle of T. gondii. These include: education programs about the parasite and avoidance of contact with infectious stages; biosecurity and sanitation to ensure food and water safety; chemo- and immunotherapeutics to control active infections and disease; prophylactic options to prevent acquisition of infection by livestock and cyst formation in meat; and vaccines to prevent shedding of oocysts by definitive feline hosts.
Topics: Animals; Cats; Female; Humans; Oocysts; Pregnancy; Prevalence; Toxoplasma; Toxoplasmosis; Toxoplasmosis, Animal; Zoonoses
PubMed: 33347832
DOI: 10.1016/j.ijpara.2020.11.001 -
Cell Jan 2020Toxoplasma gondii chronically infects a quarter of the world's population, and its recrudescence can cause life-threatening disease in immunocompromised individuals and...
Toxoplasma gondii chronically infects a quarter of the world's population, and its recrudescence can cause life-threatening disease in immunocompromised individuals and recurrent ocular lesions in the immunocompetent. Acute-stage tachyzoites differentiate into chronic-stage bradyzoites, which form intracellular cysts resistant to immune clearance and existing therapies. The molecular basis of this differentiation is unknown, despite being efficiently triggered by stresses in culture. Through Cas9-mediated screening and single-cell profiling, we identify a Myb-like transcription factor (BFD1) necessary for differentiation in cell culture and in mice. BFD1 accumulates during stress and its synthetic expression is sufficient to drive differentiation. Consistent with its function as a transcription factor, BFD1 binds the promoters of many stage-specific genes and represents a counterpoint to the ApiAP2 factors that dominate our current view of parasite gene regulation. BFD1 provides a genetic switch to study and control Toxoplasma differentiation and will inform prevention and treatment of chronic infections.
Topics: Animals; Cell Differentiation; Female; Fibroblasts; Gene Expression Regulation; Humans; Mice; Mice, Inbred Strains; Phylogeny; Promoter Regions, Genetic; Protozoan Proteins; Toxoplasma; Toxoplasmosis; Transcription Factors
PubMed: 31955846
DOI: 10.1016/j.cell.2019.12.013 -
Turkiye Parazitolojii Dergisi Jun 2020Toxoplasmosis is a common infection worldwide caused by , an intracellular parasite. The prevalence of Toxoplasmosis ranges from 17.5% to 69.5% in Turkey. Toxoplasmosis... (Review)
Review
Toxoplasmosis is a common infection worldwide caused by , an intracellular parasite. The prevalence of Toxoplasmosis ranges from 17.5% to 69.5% in Turkey. Toxoplasmosis is mostly asymptomatic. It may cause fetal mortality in case of vertical passage. The most common clinical findings in congenital toxoplasmosis are chorioretinitis, hydrocephalus and cerebral calcification. Another group of susceptible patients for are immunesuppressive patients. Reactivation of a latent infection in the case of immunodeficiency can lead to fatal toxoplasmic encephalitis. Serological diagnostic methods based on the detection of specific antibodies for are the most commonly used diagnostic methods. However, it may be difficult to interpret the results in pregnant women, neonates, and the patients receiving treatment. It is stated that using more than one method together to improve the reliability of the diagnosis is a more accurate approach. In the prenatal diagnosis of congenital toxoplasmosis, in patients with immunodeficiency, in ocular toxoplasmosis, the polymerase chain reaction is seen as having a higher sensitivity. The aim of this review is to present the general features, diagnostic methods and current approaches in toxoplasma infection, an important public health problem.
Topics: Adult; Antibodies, Protozoan; Female; Humans; Immunocompromised Host; Infant, Newborn; Infectious Disease Transmission, Vertical; Polymerase Chain Reaction; Pregnancy; Pregnancy Complications, Parasitic; Prenatal Diagnosis; Prevalence; Reproducibility of Results; Toxoplasma; Toxoplasmosis; Toxoplasmosis, Congenital; Turkey
PubMed: 32482042
DOI: 10.4274/tpd.galenos.2020.6634 -
Clinical Microbiology Reviews Oct 2018Primary infection is usually subclinical, but cervical lymphadenopathy or ocular disease can be present in some patients. Active infection is characterized by... (Review)
Review
Primary infection is usually subclinical, but cervical lymphadenopathy or ocular disease can be present in some patients. Active infection is characterized by tachyzoites, while tissue cysts characterize latent disease. Infection in the fetus and in immunocompromised patients can cause devastating disease. The combination of pyrimethamine and sulfadiazine (pyr-sulf), targeting the active stage of the infection, is the current gold standard for treating toxoplasmosis, but failure rates remain significant. Although other regimens are available, including pyrimethamine in combination with clindamycin, atovaquone, clarithromycin, or azithromycin or monotherapy with trimethoprim-sulfamethoxazole (TMP-SMX) or atovaquone, none have been found to be superior to pyr-sulf, and no regimen is active against the latent stage of the infection. Furthermore, the efficacy of these regimens against ocular disease remains uncertain. In multiple studies, systematic screening for infection during gestation, followed by treatment with spiramycin for acute maternal infections and with pyr-sulf for those with established fetal infection, has been shown to be effective at preventing vertical transmission and minimizing the severity of congenital toxoplasmosis (CT). Despite significant progress in treating human disease, there is a strong impetus to develop novel therapeutics for both the acute and latent forms of the infection. Here we present an overview of toxoplasmosis treatment in humans and in animal models. Additional research is needed to identify novel drugs by use of innovative high-throughput screening technologies and to improve experimental models to reflect human disease. Such advances will pave the way for lead candidates to be tested in thoroughly designed clinical trials in defined patient populations.
Topics: Animals; Antiprotozoal Agents; Drug Discovery; Humans; Models, Animal; Toxoplasmosis
PubMed: 30209035
DOI: 10.1128/CMR.00057-17 -
Case Reports in Ophthalmology 2022Neuroretinitis is an inflammatory condition with rapid unilateral vision loss, optic disc edema, and macular star formation. While neuroretinitis is commonly due to...
Neuroretinitis is an inflammatory condition with rapid unilateral vision loss, optic disc edema, and macular star formation. While neuroretinitis is commonly due to infectious causes such as , neuroretinitis due to toxoplasmosis is uncommon. A 29-year-old male presents to our neuro-ophthalmology clinic on December 7, 2021, at the University of Arkansas for Medical Sciences with symptoms of left eye pain and blurred vision. Subsequent workup led to the diagnosis and treatment of toxoplasma neuroretinitis. The fundus exam eventually demonstrated a notable macular star. Treatment was well tolerated, and the patient regained total visual acuity in the affected eye. Toxoplasma neuroretinitis is known for a characteristic appearance of optic disc edema prior to appearance of stellate maculopathy with vitreous inflammation and peripheral chorioretinal scars. Although loss of vision due to toxoplasmosis is rare, it should be included as part of the differential diagnosis with pertinent history.
PubMed: 36845446
DOI: 10.1159/000526682 -
Virulence Dec 2021is a parasitic protist infecting a wide group of warm-blooded animals, ranging from birds to humans. While this infection is usually asymptomatic in healthy...
is a parasitic protist infecting a wide group of warm-blooded animals, ranging from birds to humans. While this infection is usually asymptomatic in healthy individuals, it can also lead to severe ocular or neurological outcomes in immunocompromised individuals or in developing fetuses. This obligate intracellular parasite has the ability to infect a considerable range of nucleated cells and can propagate in the intermediate host. Yet, under the pressure of the immune system it transforms into an encysted persistent form residing primarily in the brain and muscle tissues. Encysted parasites, which are resistant to current medication, may reactivate and give rise to an acute infection. The clinical outcome of toxoplasmosis depends on a complex balance between the host immune response and parasite virulence factors. Susceptibility to the disease is thus determined by both parasite strains and host species. Recent advances on our understanding of host cell-parasite interactions and parasite virulence have brought new insights into the pathophysiology of infection and are summarized here.
Topics: Animals; Host-Parasite Interactions; Toxoplasma; Toxoplasmosis; Virulence; Virulence Factors
PubMed: 34895084
DOI: 10.1080/21505594.2021.2012346 -
The Journal of Clinical Investigation Jul 2020Toxoplasma gondii is an incredibly successful parasite owing in part to its ability to persist within cells for the life of the host. Remarkably, at least 350 host... (Review)
Review
Toxoplasma gondii is an incredibly successful parasite owing in part to its ability to persist within cells for the life of the host. Remarkably, at least 350 host species of T. gondii have been described to date, and it is estimated that 30% of the global human population is chronically infected. The importance of T. gondii in human health was made clear with the first reports of congenital toxoplasmosis in the 1940s. However, the AIDS crisis in the 1980s revealed the prevalence of chronic infection, as patients presented with reactivated chronic toxoplasmosis, underscoring the importance of an intact immune system for parasite control. In the last 40 years, there has been tremendous progress toward understanding the biology of T. gondii infection using rodent models, human cell experimental systems, and clinical data. However, there are still major holes in our understanding of T. gondii biology, including the genes controlling parasite development, the mechanisms of cell-intrinsic immunity to T. gondii in the brain and muscle, and the long-term effects of infection on host homeostasis. The need to better understand the biology of chronic infection is underscored by the recent rise in ocular disease associated with emerging haplotypes of T. gondii and our lack of effective treatments to sterilize chronic infection. This Review discusses the cell types and molecular mediators, both host and parasite, that facilitate persistent T. gondii infection. We highlight the consequences of chronic infection for tissue-specific pathology and identify open questions in this area of host-Toxoplasma interactions.
Topics: Animals; Disease Models, Animal; History, 20th Century; History, 21st Century; Humans; Toxoplasma; Toxoplasmosis
PubMed: 32609097
DOI: 10.1172/JCI136226 -
Frontiers in Cellular and Infection... 2021
Topics: Antibodies, Protozoan; Biology; Humans; Toxoplasma; Toxoplasmosis, Ocular
PubMed: 33768015
DOI: 10.3389/fcimb.2021.652637 -
Saudi Journal of Ophthalmology :... 2018A number of ocular diseases can be attributed to contaminated water and we have coined a term "Water-related ocular diseases (WRODs)" to denote this wide-spectrum of... (Review)
Review
A number of ocular diseases can be attributed to contaminated water and we have coined a term "Water-related ocular diseases (WRODs)" to denote this wide-spectrum of conditions. WRODs are directly related to human contact with water and can occur through toxic, allergic, inflammatory or infective mechanisms. The non-infective causes can include chemicals used to clean swimming pools, oil spills and water-sport related injuries. Similarly, a number of infective organisms causing ocular diseases are transmitted through water. Since, these conditions can occasionally prove devastating, a review was done with the following aims: (i) To study the epidemiology of WRODs (ii) To assess the clinical presentation and current management of WRODs (iii) To highlight the future challenges and possible solutions to these problems. The online search was conducted utilizing search engines such as PubMed, Google Scholar, ClinicalKey and the Virtual Library of the Ministry of Health, Malaysia for relevant terms such as water-borne, swimming pool and eye infections.
PubMed: 30224888
DOI: 10.1016/j.sjopt.2017.10.009