Dynamics of Zoonotic Disease at the One Health Interface: Evidence from a Systematic Review

Abstract

Correction (Version 2 — 10 July 2026): The original article's thesis — that Africa is deficient in zoonotic-disease trials, evidenced by zoonotic disease being only ~0.3% of African trials — is WITHDRAWN as a denominator artifact. Recomputed from ClinicalTrials.gov/AACT, African sites host 22.92% of zoonotic-condition trials, 5.3× the 4.33% baseline African share of all trials: Africa is over-represented in zoonotic trials, exactly as the epidemiology (Ebola/Marburg/Rift Valley/Lassa are intrinsically African) predicts. Recycled and anachronistic reference PMIDs have been corrected. Corrected finding: the real gaps are a global scarcity of zoonotic trials, an outbreak-reactive research cycle, neglect of endemic zoonoses (rabies, brucellosis, anthrax), and an African investigator-leadership gap.

Background. Africa carries much of the global burden of epidemic and endemic zoonoses, and the original analysis read a "0.3% zoonotic trial share" as African research neglect. We test that framing reproducibly.

Methods. Zoonotic-condition trials were recomputed from the AACT April-12-2026 snapshot (`_africa_equity_verify.py`), with like-for-like and baseline comparisons (`53-zoonotic-verify.py`). Every PMID was re-verified against PubMed metadata.

Results. African sites host 99 of 432 zoonotic-condition trials (22.92%; interventional 69/344, 20.06%) — 5.3× the 4.33% baseline African trial share. Zoonotic disease is 0.39% of African trials but only 0.075% of global trials (5.3× higher in Africa). So the "0.3%" is a denominator artifact, not a deficit. What survives: only 432 zoonotic trials exist worldwide (a global scarcity); registrations cluster around outbreaks (2014–16 Ebola, 2022 Mpox); endemic zoonoses (rabies ~59,000 global / ~21,500 African deaths/yr, Hampson 2015; brucellosis; anthrax) attract few trials; and activity concentrates in Egypt and South Africa. Emergence context is verified: 60.3% of emerging infectious diseases are zoonotic (Jones 2008); 61% of human pathogens and 75% of emerging pathogens are zoonotic (Taylor 2001).

Conclusion. Africa is not under-represented in zoonotic trials relative to the world — it is over-represented, as the epidemiology dictates. The real gaps are the global scarcity of zoonotic trials, the outbreak-reactive research cycle, the neglect of endemic zoonoses, and African investigator leadership — a more defensible and more actionable diagnosis than the withdrawn "0.3% deficit."

---