Building Programs to Eradicate Toxoplasmosis Part IV: Understanding and Development of Public Health Strategies and Advances "Take a Village"

Abstract

Purpose of review: Review international efforts to build a global public health initiative focused on toxoplasmosis with spillover benefits to save lives, sight, cognition and motor function benefiting maternal and child health.

Recent findings: Multiple countries' efforts to eliminate toxoplasmosis demonstrate progress and context for this review and new work.

Summary: Problems with potential solutions proposed include accessibility of accurate, inexpensive diagnostic testing, pre-natal screening and facilitating tools, missed and delayed neonatal diagnosis, restricted access, high costs, delays in obtaining medicines emergently, delayed insurance pre-approvals and high medicare copays taking considerable physician time and effort, harmful shortcuts being taken in methods to prepare medicines in settings where access is restricted, reluctance to perform ventriculoperitoneal shunts promptly when needed without recognition of potential benefit, access to resources for care, especially for marginalized populations, and limited use of recent advances in management of neurologic and retinal disease which can lead to good outcomes.

Supplementary information: The online version contains supplementary material available at 10.1007/s40124-022-00268-x.

Keywords: antiparasitic treatment; congenital toxoplasmosis; diagnostic testing; marginalized populations; point-of-care testing; prenatal screening.

Fig. 1

Results of characterization of the six congenitally infected children in Ciudad de Panama who presented for care at the new perinatal infections program in 2016-2017. The only asymptomatic child of the six (patient 1) corresponded to the only mother who was screened during gestation and given prenatal treatment with spiramycin. The other, unscreened mothers gave birth to children who had clinical manifestations such as hydrocephalus and diabetes insipidus

Fig. 2

Model of a distribution scheme to multiple hospitals with a central distribution site for medicines that can be used to treat toxoplasmosis. As distribution of medicines can be a significant issue for any country, this figure also addresses challenges with supplying medicines such as pyrimethamine in the United States

Fig. 3

Vishan Dhamsania, Nick Graves, Marci Kirchberg and Kopal Mathur considered international development strategies for bringing toxoplasmosis screening and treatment to the Embera, an indigenous group in Panamá. The student group evaluated what strengths and weaknesses of the Panamanian Ministry of Health (MINSA) and non-governmental organizations (NGOs) would be to implement screening programs for toxoplasmosis for the Embera. They considered the following criteria for successful implementation for a program: politics, economics, culture and sustainability. They found complementary strengths from MINSA and NGOs

Fig. 4.

Testing of the Lateral Immunochromatography G and M test with whole blood from finger stick. Part I: A. Method used in study. B. Description of early results (from PLoS Neglected Tropical Diseases with permission). C. Brochure that will be the instructional material for when this is used in clinical practice, as in package insert shown with instructions for use of kit. Images show method used step by step. Part II: D. Representative results for serum or whole blood in this test. E. Example of obtaining blood by fingerstick, example of positive bands(T) and negative result (no T but C-control-band, C, sera , left, whole blood -right. F. Our expectation is that this global initiative to address the significant health problems toxoplasmosis presents, as a focus of the programs being built, will have spillover benefit to promote well-being, improve water supply reducing other water borne diseases, in addition to preventing devastating consequences of this infection. The opportunity for spillover benefit for diagnosing and treating other diseases, and the opportunity for understanding basic, translational aspects of the biology, developing vaccines and better medicines are another substantial benefit of this global initiative. Bii, D, F. With permission PloS Neglected Tropical Diseases, E. UChicago, article by  John Easton

Fig. 4.

Testing of the Lateral Immunochromatography G and M test with whole blood from finger stick. Part I: A. Method used in study. B. Description of early results (from PLoS Neglected Tropical Diseases with permission). C. Brochure that will be the instructional material for when this is used in clinical practice, as in package insert shown with instructions for use of kit. Images show method used step by step. Part II: D. Representative results for serum or whole blood in this test. E. Example of obtaining blood by fingerstick, example of positive bands(T) and negative result (no T but C-control-band, C, sera , left, whole blood -right. F. Our expectation is that this global initiative to address the significant health problems toxoplasmosis presents, as a focus of the programs being built, will have spillover benefit to promote well-being, improve water supply reducing other water borne diseases, in addition to preventing devastating consequences of this infection. The opportunity for spillover benefit for diagnosing and treating other diseases, and the opportunity for understanding basic, translational aspects of the biology, developing vaccines and better medicines are another substantial benefit of this global initiative. Bii, D, F. With permission PloS Neglected Tropical Diseases, E. UChicago, article by  John Easton

Fig. 5

The Future. Recent studies in Chicago to develop medicines and vaccines, and an intranasal nano-vaccine and a dendrimer RNA vaccine developed by others (I). Part I. A potent tetrahydroquinolone effective against tachyzoites and bradyzoites in vitro, synergistic with atovaquone, eliminates >95% of encysted bradyzoites in vivo,, while active with a single oral dose of a nano formulation against tachyzoite infection and Plasmodium berghei’s three life cycle stages. Specifically reproduced with permission from Frontiers Cell Infection Microbiol : Figure and Legend directly from this paper. “JAG21 is a mature lead that protects against Toxoplasma gondii and Plasmodium berghei in vivo. (A) JAG21 treatment for 14 days protects against T. gondii tachyzoites in vivo. Tachyzoite challenge with Prugneaud luciferase parasites imaged with leuciferin using IVIS demonstrates that treatment with JAG21 eliminates leuciferase expressing parasites and leads to 100% survival of JAG21 treated infected mice. No cysts were found in brains of mice at 30 days after infection when they have been treated with JAG21 for the first 14 days after infection. There were 2 biological replicate experiments with 5 mice per group with similar results. (B) JAG21 and JAG21 plus tafenoquine markedly reduce Me49 strain brain cyst numbers in vivo in Balb/C mice at 30 days after infection. Parasites were quantitated by scanning the entire immunoperoxidase stained slide in an automated manner and by two observers blinded to the experimental treatment using microscopic evaluation. In each of two experiments, the numbers of mice per group were as follows: Experiment 1 had 4 diluent controls, 5 JAG21, 4 JAG21/Tafenoquine treated mice; and Experiment 2 had 5 diluent controls, 5 JAG21, 3 JAG21/Tafenoquine treated mice. Immunoperoxidase staining was performed. Parasite burden was quantitated using a positive pixel count algorithm of Aperio ImageScope software. Positive pixels were normalized to tissue area (mm²). Quantification was by counting positive pixels per square area. The entire brain in one section was scanned for each mouse. The parasite burden was quantitated as units of positive pixels per mm². The average ± S.E.M. numbers of mm² per slide quantitated was 30.2±1.6 mm² per mouse for this quantification. Each high power field of view shown in C is ~0.02 mm² per field of view. A representative single experiment is presented and the data from the two experiments analyzed together also demonstrated significant differences between the untreated and treated groups (p < 0.01; Supplemental Figure 1). (C) Microscopic evaluation of the slides reveal effect of JAG21 and JAG21 plus tafenoquine having the same pattern as the automated quantitation of immunoperoxidase stained material. There are usual appearing cysts in the DMSO control untreated mice as shown in the top panels, and rare cysts in the treated mice with most of the brown material appearing amorphous (bottom panels). (D) JAG21 nanoformulation dosages administered to P. berghei infected C57Bl6/albino mice compared with vehicle control. Design of single dose and 3 day dose experiments. (E) JAG21 nanoformulation cures P. berghei sporozoites (left panel), blood (middle panel) and liver stages, leading to 100% survival (right panel). This is with oral administration of a single dose of 2.5 mg/kg or 3 doses at 0.625 mg/kg. Single dose causal prophylaxis in 5 C57BL/6 albino mice at 2.5 mpk dosed on day 0, 1 h after intravenous administration of 10,000 P. bergheisporozoites. Shown is 3 dose causal prophylaxis treatment in 5 C57BL/6 albino mice at 0.625 mpk dosed on days −1, 0 and +1. Representative figure showing survival (right panel), luminescence (left panel) and parasitemia quantitated by flow cytometry (middle panel) for 5 mg/kg.” (F) Persisters of a RPS13 Λ strain of Toxoplasma can persist long times by exiting the cell cycle at G1 (G). The nanoformulation highly active in vivo against RH strain tachyzoites indicates that oral formulation in a conventional manner will likely be feasible. Biomarkers of illness, not shown, can also be a measure of efficacy in future studies, including circulating miRs, specific serum proteins and T2 weighted abnormalities in brain MRI. Part II. Vaccines on the horizon in pre-clinical studies. (H) Self assembling nanoparticle immunosense vaccine is potent in protection of mice (134, 137-9). RNA dendrimers also are promising in our vaccine work (Melo, Zhou, Weiss, Irvine, McLeod et al, In preparation, 2022). (I) Protection of primates eliminating death in French zoos with porous nanoparticles loaded with T.gondii lysate administered intranasally [https://www.inrae.fr/actualites/vaccine-contr-toxoplasmose-singes-saimiris]. Additional work of of others is referenced as well [100–135]. (J) Importance of screening and treating during gestation for those who are seronegative, new medicines and vaccines are emphasized in the words and image of J. Morel and her familly. Other images and Figure legend for Part I are reproduced with permission from Frontiers Cell Infect Microbiol, Nature Partners Journal Vaccines, and from Vaxinano

Fig. 5

The Future. Recent studies in Chicago to develop medicines and vaccines, and an intranasal nano-vaccine and a dendrimer RNA vaccine developed by others (I). Part I. A potent tetrahydroquinolone effective against tachyzoites and bradyzoites in vitro, synergistic with atovaquone, eliminates >95% of encysted bradyzoites in vivo,, while active with a single oral dose of a nano formulation against tachyzoite infection and Plasmodium berghei’s three life cycle stages. Specifically reproduced with permission from Frontiers Cell Infection Microbiol : Figure and Legend directly from this paper. “JAG21 is a mature lead that protects against Toxoplasma gondii and Plasmodium berghei in vivo. (A) JAG21 treatment for 14 days protects against T. gondii tachyzoites in vivo. Tachyzoite challenge with Prugneaud luciferase parasites imaged with leuciferin using IVIS demonstrates that treatment with JAG21 eliminates leuciferase expressing parasites and leads to 100% survival of JAG21 treated infected mice. No cysts were found in brains of mice at 30 days after infection when they have been treated with JAG21 for the first 14 days after infection. There were 2 biological replicate experiments with 5 mice per group with similar results. (B) JAG21 and JAG21 plus tafenoquine markedly reduce Me49 strain brain cyst numbers in vivo in Balb/C mice at 30 days after infection. Parasites were quantitated by scanning the entire immunoperoxidase stained slide in an automated manner and by two observers blinded to the experimental treatment using microscopic evaluation. In each of two experiments, the numbers of mice per group were as follows: Experiment 1 had 4 diluent controls, 5 JAG21, 4 JAG21/Tafenoquine treated mice; and Experiment 2 had 5 diluent controls, 5 JAG21, 3 JAG21/Tafenoquine treated mice. Immunoperoxidase staining was performed. Parasite burden was quantitated using a positive pixel count algorithm of Aperio ImageScope software. Positive pixels were normalized to tissue area (mm²). Quantification was by counting positive pixels per square area. The entire brain in one section was scanned for each mouse. The parasite burden was quantitated as units of positive pixels per mm². The average ± S.E.M. numbers of mm² per slide quantitated was 30.2±1.6 mm² per mouse for this quantification. Each high power field of view shown in C is ~0.02 mm² per field of view. A representative single experiment is presented and the data from the two experiments analyzed together also demonstrated significant differences between the untreated and treated groups (p < 0.01; Supplemental Figure 1). (C) Microscopic evaluation of the slides reveal effect of JAG21 and JAG21 plus tafenoquine having the same pattern as the automated quantitation of immunoperoxidase stained material. There are usual appearing cysts in the DMSO control untreated mice as shown in the top panels, and rare cysts in the treated mice with most of the brown material appearing amorphous (bottom panels). (D) JAG21 nanoformulation dosages administered to P. berghei infected C57Bl6/albino mice compared with vehicle control. Design of single dose and 3 day dose experiments. (E) JAG21 nanoformulation cures P. berghei sporozoites (left panel), blood (middle panel) and liver stages, leading to 100% survival (right panel). This is with oral administration of a single dose of 2.5 mg/kg or 3 doses at 0.625 mg/kg. Single dose causal prophylaxis in 5 C57BL/6 albino mice at 2.5 mpk dosed on day 0, 1 h after intravenous administration of 10,000 P. bergheisporozoites. Shown is 3 dose causal prophylaxis treatment in 5 C57BL/6 albino mice at 0.625 mpk dosed on days −1, 0 and +1. Representative figure showing survival (right panel), luminescence (left panel) and parasitemia quantitated by flow cytometry (middle panel) for 5 mg/kg.” (F) Persisters of a RPS13 Λ strain of Toxoplasma can persist long times by exiting the cell cycle at G1 (G). The nanoformulation highly active in vivo against RH strain tachyzoites indicates that oral formulation in a conventional manner will likely be feasible. Biomarkers of illness, not shown, can also be a measure of efficacy in future studies, including circulating miRs, specific serum proteins and T2 weighted abnormalities in brain MRI. Part II. Vaccines on the horizon in pre-clinical studies. (H) Self assembling nanoparticle immunosense vaccine is potent in protection of mice (134, 137-9). RNA dendrimers also are promising in our vaccine work (Melo, Zhou, Weiss, Irvine, McLeod et al, In preparation, 2022). (I) Protection of primates eliminating death in French zoos with porous nanoparticles loaded with T.gondii lysate administered intranasally [https://www.inrae.fr/actualites/vaccine-contr-toxoplasmose-singes-saimiris]. Additional work of of others is referenced as well [100–135]. (J) Importance of screening and treating during gestation for those who are seronegative, new medicines and vaccines are emphasized in the words and image of J. Morel and her familly. Other images and Figure legend for Part I are reproduced with permission from Frontiers Cell Infect Microbiol, Nature Partners Journal Vaccines, and from Vaxinano