Tuberculosis seroprevalence and comparison of hematology and biochemistry parameters between seropositive and seronegative captive Asian elephants of Nepal

Abstract

We conducted a tuberculosis serosurveillance program of captive elephants in Nepal and compared hematology and biochemistry parameters between seropositive and seronegative elephants. A total of 153 elephants (male=20, female=133) from four national parks were tested for TB using the ElephantTB STAT-PAK ® Assay (ChemBio Diagnostic Systems, Inc., Medford, NY, U.S.A.). The mean reported age for 138 elephants was 38.5 years (range 2-71 years).Seroprevalence for TB was 21.56% (33/153). The majority of seropositive elephants were female (n=30) and from Chitwan National Park (n=29. The occurrence of TB seropositive cases in other more remote national parks suggests TB may be widespread among the captive elephant population of Nepal. Hematology and biochemistry analyses were performed on 13 and 22 seropositive elephants, respectively and, nine elephants from a seronegative TB herd for comparison. Hematology parameters (hemoglobin, packed cell volume, platelet, white blood cells, and erythrocyte sedimentation rate) were comparable between the two groups. Total protein, globulin, and lactate dehydrogenase were significantly higher in seronegative elephants, and bilirubin was significantly higher in seropositive elephants whereas blood urea nitrogen, creatinine, glutamic oxaloacetic transaminase/aspartate aminotransferase (GOT/AST), glutamic pyruvic transaminase/alanine aminotransferase (GPT/ALT), Gamma glutamyl transferase (GT), and albumin were not significantly different. The range of biochemical parameters that were significantly different between seropositive and seronegative elephants had narrow ranges.Thus, the potential of these parameters as a direct biomarker for TB diagnosis is limited based on the findings in this study. We recommend including blood parameters in future TB surveillance studies.

Understanding Mycobacterium tuberculosis complex in elephants through a One Health approach: a systematic review

“… Malaysia Asian elephant Captive 23.30% Univariate analysis showed that elephants with assigned mahouts have significantly higher risk of TB OR = 3.8 The risk of seroconversion was significantly higher among elephants with assigned mahouts [OR = 4.9] 10 Magnuson et al (2017) [ 41 ] Clinical research Culture and Molecular Culture, PCR USA Asian elephant Captive 8.40% Molecular test results can be used to support current diagnostic procedures applied by veterinarians for treatment decisions to prevent the spread of tuberculosis in elephants. 11 Rosen et al (2018) [ 10 ] Cross sectional study Serology Elephant TB Stat-Pak and DPP VetTB Assay Zimbabwe African elephant Captive 17.10% Strong correlations were noted between contact with wild elephants and facilities ( p = 0.86) 12 Jeewan et al (2021) [ 35 ] Cross sectional study Serology Elephant TB Stat-Pak Nepal Asian elephant Captive 21.56% The occurrence of TB seropositive cases in other more remote national parks suggest TB may be wide spread among the captive elephant population of Nepal PCR Polymerase chain reaction, ELISA Enzyme-linked immunosorbent assay, TB Tuberculosis …”

“… 25 Greenwald et al (2009) [ 45 ] Asian and African elephant Captive Europe and the USA Elephant to Humans and other animals Rapid and accurate antibody tests to identify infected elephants will likely allow earlier and more efficient treatment, thus limiting the transmission of infection to other susceptible animals and to humans. 26 Mikota et al (2000) [ 15 ] Asian Elephant Captive and Free-ranging USA Elephant and human Further research is essential to validate other diagnostic test and treatment protocols 27 Jeewan et al(2021) [ 35 ] Asian elephant Captive Nepal Between elephant to other hosts, including humans Include blood parameters in future TB surveillance studies. MTB M. tuberculosis , ELISA enzyme-linked immunosorbent assay, TB tuberculosis …”

“…These elephants were in contact with domestic and wild animals like rhinos and different deer species along with their handlers [ 11 ]. Additionally, in a serosurveillance program of captive elephants in Nepal, out of 153 elephants, 21.56% were serologically tested positive [ 35 ]. There are evidences that human handlers might act as a source of infection for the animals [ 58 ].…”

Phylogenomic analysis supports Mycobacterium tuberculosis transmission between humans and elephants

“…This poses a serious risk of zooanthroponosis and disease to both captive and wild elephant populations, as well as a risk to humans given the possibility of bidirectional transmission (15,22). A recent study in four national parks in Nepal showed a high seroprevalence (21.56%) of TB in captive elephants, with most cases detected in Chitwan National Park (23). In addition, some evidence of zooanthroponosis has been reported from previous studies in Nepal that also isolated M. tuberculosis from diseased elephants using multilocus variable number of tandem repeats (MLVA) (15,24), large sequence polymorphism (24) or whole genome data (25).…”