# Diagnostic and vaccination challenges in the PPR pre-eradication era: Identifying gaps and potential unintended consequences

## TL;DR

This paper reviews challenges in diagnosing and vaccinating against Peste des petits ruminants (PPR) and highlights potential unintended consequences of eradication efforts.

## Contribution

The paper identifies key gaps in PPR eradication strategies and proposes integrating predictive modeling to address risks of disease reintroduction.

## Key findings

- Gaps in vaccine deployment and field diagnostics hinder PPR eradication progress.
- Differentiating Infected from Vaccinated Animals (DIVA) capability remains a challenge.
- Eradication could create ecological niches for other morbilliviruses to emerge or spread.

## Abstract

Peste des petits ruminants (PPRs) is a transboundary, highly contagious, notifiable, viral disease of small ruminants. In recognition of its global threat and socioeconomic impact, World Organisation for Animal Health (WOAH) and Food and Agriculture Organization (FAO) have targeted PPR for eradication by 2030, accelerating the need for robust diagnostic, surveillance, and vaccination strategies. This review synthesizes global efforts toward PPR eradication, with a particular focus on diagnostic efficacy, vaccination coverage, and the persistent challenges that hinder progress. It also addresses concerns raised in the 2024 WOAH/FAO technical review regarding potential unintended consequences of eradication—namely, the ecological niche left by rinderpest and PPR that may allow the emergence or spread of other morbilliviruses. A literature search was conducted using peer-reviewed articles (2015–2025) and recent FAO/WOAH reports. Key gaps were identified in vaccine deployment, Differentiating Infected from Vaccinated Animals capability, and field diagnostics in addition to the potential unintended consequences of eradication. Finally, we advocate for the integration of predictive modeling to assess the risk of disease reintroduction and host spillover and for embedding these insights into future eradication policies.