Human risk factors associated with the presence of antibodies against <i>Mycobacterium tuberculosis</i> complex in captive Asian elephants from Chitwan valley, Nepal.
The study found a 20.2% seroprevalence of tuberculosis antibodies in captive elephants, with specific husbandry practices linked to higher risk, underscoring the need for improved biosecurity measures.
Where it sits
this study against the rest of the kisspeptin (kp-10) corpusSummary and findings
This study measured the presence of antibodies against Mycobacterium tuberculosis complex in 99 captive Asian elephants in Chitwan valley, Nepal. A seroprevalence of 20.2% was found, with various human risk factors associated with this seropositivity. No socio-demographic factors of mahouts were linked to elephant seropositivity.
Abstract
Tuberculosis (TB) caused by <i>Mycobacterium tuberculosis</i> complex (MTC) is a growing public health concern for elephants and humans in Nepal. We tested 99 captive Asian elephants (<i>Elephas maximus</i>) in Chitwan valley for MTC antibodies and interviewed 223 mahouts to explore associations between human risk factors, husbandry practices, interspecies interactions, and MTC seropositivity. Using univariable analysis and multivariable logistic regression, we found a 20.2% seroprevalence (95% CI: 13-29%). No socio-demographic mahout factors were linked to elephant seropositivity. Significant risk factors included government/NTNC ownership (OR = 7.74; 95% CI: 2.8-21.44), hand-feeding (<i>P</i> = 0.006), lack of personal protective equipment (PPE; OR = 0.25 for use; 95% CI: 0.08-0.81), pit-based waste disposal (OR = 4.11; 95% CI: 1.7-9.94), livestock proximity (OR = 3.94; 95% CI: 1.62-9.57), and mahouts collecting dead animals for consumption (OR = 3.29; 95% CI: 1.1-9.8). Wild elephant interactions were protective (OR = 0.36; 95% CI: 0.15-0.86), suggesting lower MTC prevalence in wild populations, though captive-to-wild transmission remains a concern. These findings underscore the need for a One Health approach, integrating enhanced biosecurity, PPE promotion, improved waste management, livestock TB control, and community education to mitigate zoonotic TB risks and protect elephant welfare, mahout health, and conservation efforts in Chitwan.
Background
The study addresses the public health concern of tuberculosis caused by Mycobacterium tuberculosis complex in elephants and humans in Nepal. Previous studies have indicated the potential for zoonotic transmission of TB from elephants to humans. Understanding the risk factors associated with MTC seropositivity in captive elephants is crucial for developing effective management strategies.
Methods
The study involved testing 99 captive Asian elephants for MTC antibodies and conducting interviews with 223 mahouts. The analysis utilized univariable and multivariable logistic regression to identify associations between human risk factors and elephant seropositivity. The primary outcome measure was the presence of MTC antibodies in elephants.
Results
The primary endpoint revealed a seroprevalence of 20.2% for MTC antibodies among the elephants tested, with a 95% confidence interval of 13-29%. Significant risk factors for seropositivity included government/NTNC ownership (OR=7.74, 95% CI: 2.8-21.44) and hand-feeding (P=0.006). Other notable risk factors included lack of PPE, pit-based waste disposal, livestock proximity, and mahouts collecting dead animals.
Interpretation
The findings indicate a significant association between certain husbandry practices and MTC seropositivity in elephants, which aligns with previous literature on zoonotic TB risks. However, the effect sizes for some risk factors, while statistically significant, may not be clinically meaningful due to the small sample size. The study's reliance on self-reported data from mahouts introduces potential biases, limiting the conclusions that can be drawn.
Key findings
- 20.2% seroprevalence of MTC antibodies among elephants, 95% CI: 13-29%
- OR=7.74 for government/NTNC ownership, 95% CI: 2.8-21.44
- OR=0.25 for use of PPE, 95% CI: 0.08-0.81
- OR=4.11 for pit-based waste disposal, 95% CI: 1.7-9.94
- OR=3.94 for livestock proximity, 95% CI: 1.62-9.57
- OR=3.29 for mahouts collecting dead animals for consumption, 95% CI: 1.1-9.8
Limitations
- small sample size of n=99 elephants
- reliance on self-reported data from mahouts
- cross-sectional design limits causal inference
- no socio-demographic factors linked to seropositivity