Mycobacterium Tuberculosis and Avium Complex Investigation among Malaysian Free-Ranging Wild Boar and Wild Macaques at Wildlife-Livestock-Human Interface

Abstract

Wild animals are considered reservoirs, contributing to the transmission of emerging zoonotic diseases such as tuberculosis (TB). A cross-sectional study was conducted by opportunistic sampling from fresh carcasses of free-ranging wild boar (n = 30), and free-ranging wild macaques (n = 42). Stained smears from these tissues were tested for acid-fast bacilli (AFB) with Ziehl–Neelsen staining. Mycobacterial culture was conducted using Lowenstein–Jensen media and Middlebrook 7H11 agar media. Polymerase chain reaction (PCR) was performed through the detection of the 16S rRNA gene, with multiple sets of primers for the detection of Mycobacterium tuberculosis complex (MTBC) and Mycobacterium avium complex (MAC). In wild boars, 30% (9/30; 95% Confidence Interval: 16.7–47.9%) of examined samples showed gross tuberculosis-like lesions (TBLLs). Multiple nodular lesions that were necrotic/miliary with cavitation were found in the submandibular lymph nodes, tonsils, lungs, kidney and liver, while single nodular lesions were found in the mediastinal lymph nodes, spleen and mesenteric lymph nodes. Conventional PCR on the submandibular lymphoid tissues of wild boar (nine samples with TBLLs and three non-TBLL samples) showed that 75% (9/12) were positive for Mycobacterium bovis (95% CI: 46.8–91.1), and 91% (CI: 64.6–98.5) were positive for Mycobacterium avium. For macaques, 33.3% (10/30) were positive for M. avium (95% CI: 19.2–51.2) but negative for MTBC.

Presence of Foodborne Bacteria in Wild Boar and Wild Boar Meat—A Literature Survey for the Period 2012–2022

“…M. bovis is usually transmitted through oral ingestion, and therefore the extrapulmonary lesions in humans are more frequent than for M. tuberculosis [ 126 ]. In wild boar, the main primary complex is usually located in the submandibular and retropharyngeal lymph nodes, where the MTC is most frequently isolated [ 89 , 98 , 105 , 117 , 122 , 127 , 128 ]. Lesions were also reported in the tonsils, lung, mediastinal lymph nodes, spleen, liver, and kidney [ 106 , 117 , 127 , 128 ].…”

“…In wild boar, the main primary complex is usually located in the submandibular and retropharyngeal lymph nodes, where the MTC is most frequently isolated [ 89 , 98 , 105 , 117 , 122 , 127 , 128 ]. Lesions were also reported in the tonsils, lung, mediastinal lymph nodes, spleen, liver, and kidney [ 106 , 117 , 127 , 128 ]. The lesion in the lymph nodes is characterized by caseous or necrotic-calcified tubercles that are defined as tuberculosis-like lesions (TBLL), as other mycobacteria different from MTC (e.g., M. avium subsp.…”

Non-invasive specimen collections for Mycobacterium tuberculosis detection in free-ranging long-tailed macaques (Macaca fascicularis)

“…Moreover, in 2021 the WHO ranked Thailand as one of the countries with the highest human burdens of tuberculosis [ 31 ]. However, surveys of free-ranging long-tailed macaques living in Thailand [ 7 ] and the neighbouring Malaysia [ 32 ] did not detect MTBC with only the Mycobacterium avium complex being reported in Malaysian long-tailed macaques [ 32 ]. These negative results might reflect that the diagnostic methods were not sensitive enough to detect a very low amount of the MTBC or the condition of the collected specimens was not suitable.…”

“…For a field study, rapid molecular testing is preferable because its sensitivity is comparable to the culture method, while the specificity can be improved based on the designed primers, and it is less-time consuming. The widely used methods are conventional PCR through the detection of the 16S rRNA gene [ 32 ] or multiplex PCR through detection of IS 6110 , 32-kD alpha protein (32-kDa), and MTP40 species-specific protein ( mtp40 ) [ 7 ].…”

Wildlife Disease Monitoring: Methods and Perspectives

“…The opportunistic collection of carcasses of wild boars ( Sus scrofa ) and macaques ( Macaca fascicularis ) was employed also by Lekko et al [ 10 ] to investigate the circulation of Mycobacterium tuberculosis complex (MTBC) and Mycobacterium avium complex (MAC) at the wildlife–livestock–human interface in Malaysia. In light of their findings, the authors discuss best practices for MTBC and MAC detection and surveillance in wildlife and for limiting disease spread and transmission to livestock and humans.…”