Contagious caprine pleuropneumonia: a review and gap analysis of its impact, epidemiology, pathogenesis, and control

Contagious caprine pleuropneumonia (CCPP), caused by Mycoplasma capricolum subsp. capripneumoniae ( Mccp ), remains one of the most important small ruminant diseases and a major transboundary disease. Although primarily affecting goats, infections have also been reported in sheep and several wild ungulate species. The disease is widely distributed across Africa, Asia and the Middle East, and its persistence in the Thrace region of Turkey highlights the risk of further spread towards Europe. However, the true distribution and burden of CCPP remain uncertain because of under-reporting, limited surveillance and diagnostic challenges. This review highlights the complexity of CCPP epidemiology and the many unresolved questions regarding pathogen persistence, transmission, and host–pathogen interactions. In particular, the epidemiological significance of latent infections, asymptomatic carriage, co-infections and the role of wildlife and alternative hosts remain poorly understood. Similarly, important gaps persist in the understanding of virulence determinants and protective immune mechanisms, hampering the development of improved control tools. Laboratory diagnosis relies mainly on specialised molecular methods, while validated commercial kits and rapid pen-side tests for field diagnosis are lacking. Existing inactivated vaccines are expensive to produce and suffer from limitations in potency, thermostability and duration of protection, partly because of insufficient quality-control procedures. Novel vaccine approaches, including formulations based on fast-growing strains, subunit vaccines and synthetic biology-derived platforms, offer promising perspectives but require further validation and adapted regulatory frameworks. The widespread use of antimicrobials in the absence of evidence-based guidelines raises concerns regarding antimicrobial stewardship and the possible emergence of antimicrobial resistance. Standardised antimicrobial susceptibility testing methods and harmonised monitoring systems are therefore urgently needed to support rational therapeutic strategies. Substantial knowledge gaps also remain regarding the economic impact of CCPP and the optimisation of surveillance and control programmes. Improved reporting systems, integration of epidemiological and mobility data, participatory approaches and mathematical modelling could greatly enhance disease monitoring and risk assessment. Combining vaccination with broader animal health initiatives and implementing integrated control strategies tailored to local production systems may improve the sustainability and cost-effectiveness of disease control, particularly in low- and middle-income countries.