The objectives of this study were to evaluate the proper anticoagulants coated in blood-collecting tube for the peripheral blood mononuclear cells (PBMCs) isolation and to evaluate the proper culture temperature for the Varanus salvator’s PBMCs, in addition, the hematological characteristics also reported. The heparin treated blood (n = 10) and EDTA treated blood (n = 10) from Varanus salvator were obtained for PBMCs evaluation. The PBMCs obtained from the heparin treated blood was significantly higher than that of EDTA treated blood during the culture period (P < 0.05) indicated heparin would be more appropriated anticoagulant for blood collection. The PBMCs cultured under 37°C and 27°C were not significantly difference on first three days but 37°C showed significantly higher effect in the following days (P < 0.05) indicated both temperatures can be used which 37°C should be an optimal for PBMCs preparation. The peripheral blood cells of Varanus salvator (n = 49) were analyzed for hematological profiles and characteristics which the number of erythrocytes 1.19 ± 0.04 x 10¹²/L (1.17–1.35 x 10¹²/L) and WBC 2.41 ± 0.13 x 10⁹/L (2.29–2.81 x 10⁹/L) with absolute differential count of heterophils 0.92 ± 0.02 x 10⁹/L (0.87–0.95 x 10⁹/L), lymphocytes 1.17 ± 0.01 x 10⁹/L (1.15–1.23 x 10⁹/L), azurophils 0.40 ± 0.01 x 10⁹/L (0.37–0.42 x 10⁹/L), basophils 0.000 ± 0.001 x 10⁹/L (0.004–0.011 x 10⁹/L) and monocytes 0.027 ± 0.002 x 10⁹/L (0.028–0.039 x 10⁹/L). These results would play an important role on the cell immunological studies of the Varanus salvator in the future.

It is well known that the Asian water monitors or Varanus salvator are both scavengers and predators. They can live and survive in the place that exposed to harmful microorganisms. Most people believe that they have some protected mechanisms to confront those infections. The aim of this study is to determine the antibacterial activities of crude peptides and protein hydrolysates extracted from serum of the Varanus salvator. Ten types of bacteria were cultured with crude peptides and protein hydrolysates which were isolated from 21 Varanus salvator’s serum. The crude peptides showed some interested inhibition percentages against Enterobacter aerogenes ATCC13048 = 25.6%, Acinetobacter baumannii ATCC19606 = 33.4%, Burkholderia cepacia ATCC25416 = 35.3% and Pseudomonas aeruginosa ATCC27853 = 25.8%, whereas the protein hydrolysates had some inhibition potential on Burkholderia cepacia ATCC25416 = 24.3%. For the rest results of other tests were below 20% of inhibition. In addition, the evidences show that crude peptides have better antibacterial performances significantly than protein hydrolysates on most tested bacteria. Furthermore, antimicrobial peptides prediction shows about 10 percent hit (41/432 sequences). The interpretation shows that the best hit sequence is highly hydrophobic. It may destroy outer membrane of Gram-negative hence prevents the invasion of those bacteria. Altogether, bioinformatics and experiments show similar trends of antimicrobial peptide efficacy from Varanus salvator. Further studies need to be conducted on peptide purification and antimicrobial peptide candidate should be identified.

Asian water monitors (Varanus salvator) are often exposed to harmful microorganisms such as species of Hepatozoon, Anaplasma, Rickettsia, and Borrelia. These pathogens pose significant risks to wildlife and public health. In this study, we aimed to investigate the presence and genetic diversity of pathogenic microorganisms in V. salvator from the Khao-zon Wildlife Breeding Station, Ratchaburi, Thailand. Sixteen V. salvator were collected, and thin blood smears and polymerase chain reaction (PCR) assays of the DNA isolated from blood were used to identify infections. Blood smear analysis revealed two positive samples (2/16; 12.5%) for Hepatozoon sp. PCR results confirmed the presence of Hepatozoon sp. (6/16; 37.5%), Anaplasma sp. (3/16; 18.75%), Rickettsia sp. (2/16; 12.5%), Borrelia sp. (4/16; 25.0%) and Burkholderia sp. (1/16; 6.25%). Phylogenetic analysis revealed 99.86% similarity of Hepatozoon sp. sequences with Hepatozoon ophisauri (GenBank: MN723845) in Pseudopus apodus from Iran, whereas the gltA gene of Rickettsia sp. was closely related to Rickettsia conorii raoultii (GenBank: MF002515) in Dermacentor nuttalli from China. This study represents the first detection of the five pathogens in V. salvator from Thailand and provides valuable insights into the genetic diversity of these microorganisms. Our findings suggest that V. salvator may serve as reservoir for multiple pathogens, posing potential threats to both wildlife and humans. The presence of zoonotic agents such as Rickettsia spp., Anaplasma spp., and Borrelia spp. underscores the importance of continued surveillance in wildlife populations to mitigate the risk of emerging infectious diseases.

In Thailand, small- to medium-scale (SM) dairy farms typically have fewer than 100 cows. They are often family-owned or independently operated, and vary in infrastructure and mechanization depending on their size. In contrast, large-scale (L) farms, with more than 100 cows, are more industrialized, utilizing advanced technology, higher production systems, and usually employ multiple workers. To date, few studies have reported the prevalence of methicillin-resistant staphylococci (MRS) and methicillin-susceptible staphylococci (MSS) and their antimicrobial resistance (AMR) at different farm scales. This study aimed to investigate the prevalence of Staphylococcus spp., MRS, MSS and their AMR as well as their genetic backgrounds on SM and L dairy farms in Thailand. A total of 157 mastitis milk samples were collected from 106 cows on 42 SM farms, and 65 samples from 37 cows on one L farm, all located in Kanchanaburi Province. Antimicrobial susceptibility testing was conducted by determining the minimum inhibitory concentration. Whole-genome sequencing and analysis were performed for genetic characterization. There was a significant difference in the prevalence of Staphylococcus spp. on L farm (26.2%) and SM farms (14%) (P = 0.031, χ² test). The phenotypic resistance of trimethoprim/sulfamethoxazole in L farm (58.8%) was significantly greater than that in SM farms (27.3%) (P = 0.049, χ² test). Six methicillin-resistant staphylococci (27.3%), including Staph. haemolyticus sequence type (ST) 3 (N = 1) and ST42 (N = 3) and Staph. epidermidis ST59 (N = 2) were discovered on SM farms, whereas a single Staph. aureus ST398 (5.9%, N = 1) was found on an L farm. These strains were multidrug-resistant and carried multiple, diverse antimicrobial resistance genes, including β-lactam resistance genes (mecA, blaZ), tetracycline resistance genes [tet(K), tet(M)], and macrolide resistance genes [msr(A), mph(C)]. Compared with MRS, MSS carried fewer diverse antimicrobial resistance genes and had distinct STs at both farm scales. At each farm scale, a particular type of resistance may originate from a certain species or specific ST. In conclusion, the prevalence of Staphylococcus spp. and their resistance traits and genetic background on SM and L farms differ according to different production farm scales. The specific management and monitoring of the information on Staphylococcus spp. circulated on each farm type could help to limit the spread of antimicrobial-resistant staphylococci.

Asian water monitors (Varanus salvator) serve as significant hosts for ticks in Southeast Asia, yet the diversity of microorganisms potentially vectored or endosymbiotic within their ticks in Western Thailand remains underexplored. This study investigated the occurrence and genetic diversity of tick-associated microorganisms in ticks parasitizing this varanid species at the Khaozon Wildlife Breeding Center (KWBC), Ratchaburi Province. Morphological and molecular analyses confirmed that all 30 adult ticks collected were Amblyomma varanense (Arachnida: Ixodidae). PCR-based analysis coupled with DNA sequencing revealed that Rickettsia was the most prevalent microorganism detected (90.0%, 27/30), with gltA sequences genetically clustering within the spotted fever group (SFG) and closely related to the human pathogenic Rickettsia monacensis and Rickettsia tamurae. Utilizing the flaB gene, Borrelia spp. were identified in 76.66% (23/30) of ticks, forming lineages within the reptile-associated (REP) clade, distinct from Lyme borreliosis (LB) group. Furthermore, Hepatozoon sp. and Hemolivia sp. were each identified in 3.33% (1/30) of ticks; notably, this represents the first molecular record of Hemolivia sp. in A. varanense from a varanid host. Nevertheless, this discovery relies on a single genetic marker (18S rRNA gene). Our study revealed a diverse microbial community in varanid-associated A. varanense ticks at the KWBC. Despite the absence of human infections by reptile-associated Borrelia spp. and Rickettsia spp., the existence of these microorganisms underscores the critical need for ongoing One Health surveillance at this anthropogenic-forest interface.

This study investigated the anticancer efficacy of <3 kDa fractions derived from native peptides and protein hydrolysate of Varanus saltator serum. The inhibitory effects of these fractions were evaluated against a panel of cancer cell lines (A375, CaCO2, CAL27, NCI-H460, HeLa, HCT8, HT29, HepG2, KATO III, MCF-7, MDA-MB-231, Raw264.7, SKOV-3, SW620, T47D, and U937) and normal cell lines (HaCaT, MRC5, and Vero). Native peptides demonstrated higher anticancer activity compared to protein hydrolysates, inhibiting 16 cell lines and exhibiting high efficacy (≥70% inhibition) against CaCO2, CAL27, HaCaT, HT29, HepG2, MCF-7, MRC5, and U937. These native peptides were further fractionated by stepwise reverse-phase column chromatography. The hydrophilic (C18 unbound) peptide fraction exhibited greater anticancer activity than the hydrophobic (C18 bound) fraction. In addition, by LC-MS analysis, the peptide sequences were screening in silico. The predictions showed that 159 of the 432 Varanus peptides had the potential to be anticancer peptides (ACPs), of which the top twenty had a probability of more than 75%. The anticancer mechanism of peptides may be explained by the mechanism of cell entry or action. Further peptide synthesis and modification should be the next step to enhance the anticancer efficacy of these peptides with less toxicity to Vero cells. This finding sets the way for the development of new anticancer drugs originating from Varanus salvator serum peptides.