Meta-analysis and systematic review of the prevalence and risk factors of animal fascioliasis in Eastern and Southern Africa between 2000 and 2023.

Overview

• This study systematically reviewed and meta-analyzed the prevalence and risk factors of animal fascioliasis in Eastern and Southern Africa from 2000 to 2023.
• The research highlights the significant burden of fascioliasis across various livestock species in the region and the need for improved control measures.

Background

• Fascioliasis is a zoonotic disease caused by two species of liver flukes: Fasciola hepatica and Fasciola gigantica.
• The parasites primarily infest the liver, especially the bile ducts, causing damage that leads to clinical and economic consequences.
• Economic losses include:
  • Emaciation of animals
  • Reduction in milk production
  • Death and infertility
  • Losses due to liver condemnation during meat inspection
• Despite its impact, fascioliasis remains understudied in low- and middle-income countries, with sparse data to inform interventions.

Objective

• To analyze and summarize the prevalence of fascioliasis in different animal species across Eastern and Southern Africa over the period 2000–2023.
• To identify and review known risk factors associated with fascioliasis in the studied regions.

Methodology

• A systematic search following PRISMA guidelines was conducted through databases including Science Direct, PubMed, and Google Scholar.
• Studies published between 2000 and 2023 relevant to animal fascioliasis in Eastern and Southern Africa were included.
• A total of 106 eligible studies were identified and selected based on inclusion criteria.
• Data extracted from these studies were analyzed quantitatively and qualitatively using the R software meta package (version 4.21).
• Prevalence estimates and confidence intervals were calculated, and forest plots were generated to visualize subgroup data.
• The Cochran’s Q statistic was used to assess heterogeneity across studies.

Key Findings

• The overall prevalence of fascioliasis varied by animal species, with the following estimates (with 95% confidence intervals):
  • Mules: 47.5% (38.0–57.2%) – highest prevalence observed
  • Sheep: 23.3% (17.0–31.1%)
  • Cattle: 23.4% (19.2–28.2%)
  • Donkeys: 23.2% (19.3–27.6%)
  • Horses: 12.2% (9.9–14.8%)
  • Goats: 7.9% (5.4–11.5%) – lowest prevalence observed
• These prevalence rates underscore fascioliasis as a significant parasitic disease affecting a wide range of domestic animals in the region.
• The study aggregated various risk factors, although specific factors were not detailed in the abstract, it typically includes environmental, management, and host-related factors identified from the literature.

Interpretation and Importance

• The high prevalence in mules is notable and may indicate differences in husbandry practices, exposure, or biological susceptibility.
• Moderate prevalence in common livestock such as cattle, sheep, and donkeys indicates sustained transmission and economic impact.
• The relatively lower prevalence in goats and horses might reflect species-specific susceptibility or different management conditions.
• These findings highlight the necessity of developing targeted control programs adapted to local epidemiological situations.

Recommendations

• Increased awareness campaigns regarding fascioliasis and its impact should be promoted among livestock owners and veterinarians.
• Implementation of effective prevention and control measures, including strategic deworming, improved management, and environmental interventions.
• Further research is needed to better characterize risk factors and to develop context-appropriate, evidence-based interventions.
• Policy support in low- and middle-income countries to allocate resources for fascioliasis control is essential to improve the productivity and welfare of livestock.