Meta-analysis finds high prevalence of zoonotic diseases in African pastoralist livestock systems

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Frontiers in Medicine Published April 14, 2026 Medically reviewed April 25, 2026 Study authors: Dickson Machira Nyaguthii, James Hassel, Daniel Nthiwa, Michael E. von Fricken, Ellen P. Carlin, Fra… DOI ↗ By Dr. Ji-eun Park, MD · Brain, Mind & Pain

Key Takeaway

Note high zoonotic disease prevalence in African pastoralist systems, but evidence is observational.

This systematic review and meta-analysis examined 34 studies from pastoralist systems in Africa, focusing on humans, camels, and goats. The analysis assessed disease occurrence at livestock value chain nodes (farms, etc.), with no comparator reported, and pooled prevalence data for Rift Valley fever (RVF), Crimean-Congo hemorrhagic fever (CCHF), and tularemia.

Main results showed RVF prevalence was 29% in humans (95% CI: 7-69%), 19% in camels (95% CI: 7-43%), and 6% in goats (95% CI: 4-10%). CCHF prevalence was 48% in camels (95% CI: 8-91%) and 6% in humans (95% CI: 2-19%). At livestock farms, RVF prevalence was 13% (95% CI: 10-16%) and CCHF was 15% (95% CI: 4-44%). Tularemia pooled positivity was 2% (95% CI: 0-8%). Females were more likely to test positive than males (OR=5.20, 95% CI: 3.09-8.76, p<0.01), and mixed herds showed higher RVF likelihood (OR=33.34, 95% CI: 0.72-1548.64, p=0.0734).

Safety and tolerability data were not reported. Key limitations were not specified in the input, but the wide confidence intervals indicate substantial heterogeneity and uncertainty in prevalence estimates. The observational nature of included studies prevents causal inference about livestock value chain nodes and disease transmission.

Practice relevance suggests strengthened surveillance along livestock value chain nodes may help mitigate disease transmission risk in these settings. However, clinicians should interpret these prevalence estimates cautiously due to methodological variability and lack of controlled comparisons.

Study Details

Study typeMeta analysis

EvidenceLevel 1

PublishedMar 2026

View Original Abstract ↓

Pastoralism is a livestock production system practiced in areas with harsh environmental conditions and is characterized by low investment in animal health, increasing the risk of animal disease outbreaks. Zoonotic diseases such as Crimean-Congo hemorrhagic fever (CCHF), Rift Valley fever (RVF), and tularemia may spread through livestock product value chains. Published studies on the three diseases were systematically searched in PubMed, Web of Science, Scopus, and Google Scholar using predetermined search terms. Eligible studies were screened, and full texts were reviewed for data extraction. Extracted variables included publication details, laboratory methods, and measures of disease occurrence. Studies were grouped according to livestock value chain nodes. Random-effects models were used to estimate pooled prevalence. Publication bias was assessed using Egger’s test and funnel plot symmetry. A random forest algorithm identified relevant moderators of prevalence, which were further evaluated using mixed-effects models. A total of 34 studies were included, with RVF being the most studied pathogen (64.7%), followed by CCHF (29.4%) and tularemia (5.9%). RVF prevalence was highest in humans (29%; 95% CI: 7–69%), followed by camels (19%; 95% CI: 7–43%), and lowest in goats (6%; 95% CI: 4–10%). CCHF prevalence was highest in camels (48%; 95% CI: 8–91%) and lowest in humans (6%; 95% CI: 2–19%). At the value chain level, prevalence was highest at livestock farms for both RVF (13%; 95% CI: 10–16%) and CCHF (15%; 95% CI: 4–44%). Females were more likely to test positive (OR = 5.20; 95% CI: 3.09–8.76; p < 0.01), while mixed herds showed higher likelihood of RVF positivity (OR = 33.34; 95% CI: 0.72–1548.64; p = 0.0734). Tularemia had a pooled positivity rate of 2% (95% CI: 0–8%). This review provides evidence that CCHF, RVF, and tularemia are endemic in pastoral areas. Strengthened surveillance along livestock value chain nodes is needed to mitigate the risk of disease transmission.

Meta-analysis finds high prevalence of zoonotic diseases in African pastoralist livestock systems

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Meta-analysis finds high prevalence of zoonotic diseases in African pastoralist livestock systems

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