Building Programs to Eradicate Toxoplasmosis Part I: Introduction and Overview

Abstract

Purpose of review: Review building of programs to eliminate Toxoplasma infections.

Recent findings: Morbidity and mortality from toxoplasmosis led to programs in USA, Panama, and Colombia to facilitate understanding, treatment, prevention, and regional resources, incorporating student work.

Summary: Studies foundational for building recent, regional approaches/programs are reviewed. Introduction provides an overview/review of programs in Panamá, the United States, and other countries. High prevalence/risk of exposure led to laws mandating testing in gestation, reporting, and development of broad-based teaching materials about Toxoplasma. These were tested for efficacy as learning tools for high-school students, pregnant women, medical students, physicians, scientists, public health officials and general public. Digitized, free, smart phone application effectively taught pregnant women about toxoplasmosis prevention. Perinatal infection care programs, identifying true regional risk factors, and point-of-care gestational screening facilitate prevention and care. When implemented fully across all demographics, such programs present opportunities to save lives, sight, and cognition with considerable spillover benefits for individuals and societies.

Supplementary information: The online version contains supplementary material available at 10.1007/s40124-022-00269-w.

Keywords: Brazil; Colombia; France; Morocco; Panama; United States; congenital toxoplasmosis; foundational work; medical care; public health; pyrimethamine; review; student research; sulfadiazine; toxoplasmosis.

Fig. 1

Timeline of the projects and areas of research in which “Team Panama” has participated since 2014

Fig. 2

A. Model of Toxoplasma gondii transmission between domestic and wild felids, freshwater runoff, livestock, predatory and scavenger animals, marine mammals, bivalves and other invertebrates, and humans. This model is subject to change depending on the setting, but it presents a general overview of how Toxoplasma circulates through an ecosystem and suggests ways in which transmission to humans can be stopped or limited. Adapted from Van Wormer et al. B. Relationship of Toxoplasma transmission patterns to water and soil; designed by Jorge Gómez-Marin and Lilian Bahia Oliveira, also in McLeod et al. 2022.

Fig. 3

Early studies in France, the United States, and Brazil demonstrated efficacy of treatment and shaped understanding of this disease. The images from France, those in the NCCCTS in the USA, and in Brazil represent the early chronology of this work, and show some of the investigators who worked on some of these studies. Special accomplishments of colleagues are noteworthy and have not been mentioned specifically. Since a number of those working on this study in the early years have died in the past two years with some posthumous authors they are mentioned specifically as follows: Paul Meier designed the first Toxoplasma RCT for congenital toxoplasmosis with colleagues in the NCCCTS. Michael Gottlieb’s guidance as a Program officer at NIAID was instrumental in the establishment of the NCCCTS and many aspects of development of treatments and vaccines to prevent this disease along with others continuing in this in the NIAID DMID program. Jean Hickman worked with them within NIAID. Eileen Stillwaggon worked on cost benefit analyses demonstrating predicted cost savings when there was diagnosis and treatment of congenital toxoplasmosis in the United States. In Austria she found fourteen-fold cost savings occurred. In France, early treatment in gestation has been found to be superior to treatment started after delays (Wallon, Stillwaggon, Sawyer et al 2022, In submission). Charles N Swisher was one of the primary neurologists in the NCCCTS working with this study from 1981 until his passing in 2020. Jack S Remington and his laboratory performed the serologic tests for this study and included findings from the NCCCTS in co-authored book chapters, with the work of his laboratory continuing with the study. Lazlo Stein developed the hearing testing protocols. The contributions of others either as authors or acknowledged are substantial as well. Each of these scientists, physicians, and others had an important role in the understanding and improvement in outcomes for this disease.

Fig. 4

Restoration of anatomy and clinical improvement can occur with prompt treatment and placement of VP shunt. Third ventriculostomies often fail in this infection. A. Shows a recent photo (with permission) of a child whose first neurosurgeon was adamant about not shunting this child when he was an infant. The family sought care elsewhere had a ventriculoperitoneal shunt placed quickly and the child has done well. In just the first months of 2021 this scenario has repeated itself 5 times. Each time, except one infant in Guam, the children were shunted and all improved. B. Another example of an infant with a delay in shunting with a good response shown when an entricular peritoneal shunt was placed. His spinal cord lesions and associated signs are also resolving slowly although with developmental delays. C Figures from McLone et al reproduced with permission show the restoration of anatomy and better outcomes when needed shunts are placed without delay. Each aspect of care for this disease is urgent and emergent and should be treated as expectant for favorable outcome, recognizing this does not always occur but can and does on many occasions. Images reproduced with permission.

Fig. 5

Retinal photographs and Optical Coherence Tomographic studies showing large active lesion with substantial edema (top) and then gradual near complete resolution with treatment with pyrimethamine, sulfadiazine and leucovorin and initially prednisone eye drops. This demonstrates that treatment should be initiated promptly, treatment should continue beyond resolution of the lesion, even large lesions can resolve almost entirely leaving only a small area of pigment, and no permanent detrimental change in visual acuity. An Atlas of retinal lesions is in the Supplemental, and also at toxoplasmosis.org, included herein with permission. The examples in the Atlas show the variability in appearance of lesions of toxoplasmic chorioretinitis.