# Evaluating how demography and temperature increase might alter the burden of congenital Toxoplasmosis in Africa

## TL;DR

The paper explores how rising temperatures and demographic changes in Africa might increase the risk of congenital Toxoplasmosis by altering infection patterns.

## Contribution

The study introduces a novel integration of climate and demographic models to predict future Toxoplasma gondii disease burden in Africa.

## Key findings

- Higher temperatures may reduce T. gondii oocyst survival, potentially lowering transmission.
- Reduced transmission could increase the average age of first infection, raising pregnancy-related risks.
- Demographic shifts and climate change may combine to increase congenital Toxoplasmosis burden in some African regions.

## Abstract

The impact of climate change on environmental pathogens is a question whose importance will amplify in coming years. The protozoan parasite and global zoonosis Toxoplasma gondii is one such: empirical evidence indicates that oocyst survival is reduced at high temperatures. Paradoxically, a decline in incidence of T. gondii infections could amplify the burden of this disease, as the most damaging outcome occurs subsequent to first infection during pregnancy, and reductions in the incidence of the infection will increase the average age of first infection. We blend models of infection dynamics rooted in occurrence across the African continent with models of human demography to bound expectations for the future burden of this pathogen, accounting for the effects of changing temperatures. We discuss targeting efforts and approaches for mitigation.

The pathogen Toxoplasma gondii is associated with serious health outcomes if women are infected for the first time during pregnancy. In Sub-Saharan Africa, transmission is currently sufficiently high that most women are infected before their child-bearing years. However, higher temperatures might reduce survival of the pathogen’s environmental life stage (oocysts). This could reduce transmission and put more women at risk. We evaluate the potential shift in burden associated with a changing climate in the context of changing patterns of fertility over age, identifying settings where an increase might be expected.