Dog blood parasite infection in upland and lowland communities of northern Thailand: The role of environment and care of dog owners.

Dogs play an important role as hosts and reservoirs for many zoonotic diseases. Ehrlichiosis, babesiosis and hepatozoonosis are a group of canine vector-borne diseases that can be transmitted via ectoparasites from dog to dog and also from dog to humans. This study focused on three main blood parasites of dog (i.e., Babesia spp., Ehrlichia spp. and Hepatozoon spp.) among two different landscape types of eight villages of Santhong Sub-district, Nan Province, Thailand. In this study, 149 dogs were surveyed and blood samples were collected. Blood parasite infections in dogs were assessed using molecular detection approach. Babesia canis vogeli, Babesia gibsoni, Ehrlichia canis and Hepatozoon canis were detected with prevalence of infection at 10.7%, 8.1%, 3.4% and 0.7%, respectively. In terms of landscape type, prevalence of overall blood parasites, particularly Babesia spp. infections were higher in dogs living in upland forested areas (28.3%) compared to dogs from lowland agricultural areas (12.3%). Data obtained from the questionnaires on perceptions of dog owners showed that dogs raised all the time outside owner's house, and those dogs whose owners have never bathed and cleaned were more likely to be exposed to blood parasites. As infected dogs could play an important role as reservoirs of the blood parasites, attitude of dog owners may affect public health in terms of zoonotic disease transmission. Effective control measures and surveillance program of arthropod vectors and blood parasite infection in dogs still need to be advocated to minimize zoonotic disease transmission.

A protocol and a data-based prediction to investigate virus spillover at the wildlife interface in human-dominated and protected habitats in Thailand: The Spillover Interface project.

The Spillover Interface Project aims at assessing the encounter of wildlife, domestic animals, and humans along a landscape gradient from a protected area to a residential community, through areas of reforestation and agricultural land. Here, we present the protocols of the project that combine virus screening in humans, bats, rodents and dogs with camera trapping, land-use characterization, and network analyses. The project is taking place in the sub-district of Saen Thong (Nan Province, Thailand) in collaboration with local communities, the District Public Health Office, and Nanthaburi National Park. To formulate a predictive hypothesis for the Spillover Interface Project, we assess the wildlife diversity and their viral diversity that could be observed in Saen Thong through a data science analysis approach. Potential mammalian species are estimated using data from the International Union for Conservation of Nature (IUCN) and their associated viral diversity from a published open database. A network analysis approach is used to represent and quantify the transmission of the potential viruses hosted by the mammals present in Saen Thong, according to the IUCN. A total of 57 viruses are expected to be found and shared between 43 host species, including the domestic dog and the human species. By following the protocols presented here, the Spillover Interface Project will collect the data and samples needed to test this data-driven prediction.

The risk of pig and chicken farming for carriage and transmission of Escherichia coli containing extended-spectrum beta-lactamase (ESBL) and mobile colistin resistance (mcr) genes in Thailand.

South-East Asian countries report a high prevalence of extended-spectrum cephalosporin- (ESC-) and colistin-resistant Escherichia coli (Col-R-Ec). However, there are still few studies describing the molecular mechanisms and transmission dynamics of ESC-R-Ec and, especially, Col-R-Ec. This study aimed to evaluate the prevalence and transmission dynamics of Ec containing extended spectrum beta-lactamases (ESBL) and mobile colistin resistance (mcr) genes using a 'One Health' design in Thailand. The ESC-R-Ec and Col-R-Ec isolates of human stool samples (69 pig farmers, 155 chicken farmers, and 61 non-farmers), rectal swabs from animals (269 pigs and 318 chickens), and the intestinal contents of 196 rodents were investigated. Resistance mechanisms and transmission dynamics of Ec isolates (n=638) were studied using short and long read sequencing. We found higher rates of ESBL-Ec isolates among pig farmers (n=36; 52.2%) than among chicken farmers (n=58; 37.4 %; P<0.05) and the control group (n=61; 31.1 %; P<0.05). Ec with co-occurring ESBL and mcr genes were found in 17 (6.0 %), 50 (18.6 %) and 15 (4.7 %) samples from humans, pigs and chickens, respectively. We also identified 39 (13.7 %) human samples with non-identical Ec containing ESBL and mcr. We found higher rates of ESBL-Ec, in particular CTX-M-55, isolates among pig farmers than among non-pig farmers (P<0.01). 'Clonal' animal-human transmission of ESBL-Ec and Ec with mcr genes was identified but rare as we overall found a heterogenous population structure of Ec. The Col-R-Ec from human and animal samples often carried mcr-1.1 on conjugative IncX4 plasmids. The latter has been identified in Ec of many different clonal backgrounds.

Risk factors analysis for neglected human rickettsioses in rural communities in Nan province, Thailand: A community-based observational study along a landscape gradient.

In this study, we estimated exposure for Scrub typhus (STG), Typhus (TG) and Spotted fever groups (SFG) rickettsia using serology at a fine scale (a whole sub-district administration level) of local communities in Nan Province, Thailand. Geographical characteristics of the sub-district were divided into two landscape types: lowland agricultural area in an urbanized setting (lowland-urbanized area) and upland agricultural area located close to a protected area of National Park (upland-forested area). This provided an ideal contrast between the two landscapes with low and high levels of human-altered habitats to study in differences in disease ecology. In total, 824 serum samples of participants residing in the eight villages were tested by screening IgG ELISA, and subsequently confirmed by the gold standard IgG Immunofluorescent Assay (IFA). STG and TG IgG positivity were highest with seroprevalence of 9.8% and 9.0%, respectively; whereas SFG positivity was lower at 6.9%. Inhabitants from the villages located in upland-forested area demonstrated significantly higher STG exposure, compared to those villages in the lowland-urbanized area (chi-square = 51.97, p < 0.0001). In contrast, TG exposure was significantly higher in those villagers living in lowland-urbanized area (chi-square = 28.26, p < 0.0001). In addition to the effect of landscape types, generalized linear model (GLM) analysis identified socio-demographic parameters, i.e., gender, occupation, age, educational level, domestic animal ownership (dog, cattle and poultry) as influential factors to explain the level of rickettsial exposure (antibody titers) in the communities. Our findings raise the public health awareness of rickettsiosis as a cause of undiagnosed febrile illness in the communities.

A One Health approach to assessing occupational exposure to antimicrobial resistance in Thailand: The FarmResist project.

This Southeast Asia-Europe research project will use a One Health approach to identify the major parameters responsible for the presence of animal-associated antimicrobial resistant bacteria in animal production facilities in Thailand and the risk of their transmission from animals to humans. We will focus on traditional, small, extensive pig and poultry farms where information on antibiotic use is scarce and animals live in close contact with humans. This cross-sectional study will be based on the epidemiological analysis of the antimicrobial resistance (AMR) present in fecal samples from animals and humans. Extended spectrum beta-lactamase producing Enterobacteriaceae (ESBL-E) and Enterobacteriaceae resistant to colistin will be actively searched in the feces of farm animals (pigs and poultry), small wild rodents and farmers. Phenotypic (selective plating) and genotypic (multilocus seuquence typing and sequencing) methods will be used for the detection of AMR, the identification of antibiotic resistance genes (ARGs) and the characterization of strains carrying resistance genes. Questionnaires will be administered to investigate the effects of antibiotic use, farm characteristics and biosecurity measures on the occurrence of AMR in animals. Subsequently, the fecal carriage of AMR and ARGs in farmers will be compared to a control population with no occupational contacts with animals, thus enabling an estimation of the risk of transmission of AMR/ARGs from animals to farmers.

Intestinal parasites in rural communities in Nan Province, Thailand: changes in bacterial gut microbiota associated with minute intestinal fluke infection.

Gastrointestinal helminth infection likely affects the gut microbiome, in turn affecting host health. To investigate the effect of intestinal parasite status on the gut microbiome, parasitic infection surveys were conducted in communities in Nan Province, Thailand. In total, 1047 participants submitted stool samples for intestinal parasite examination, and 391 parasite-positive cases were identified, equating to an infection prevalence of 37.3%. Intestinal protozoan species were less prevalent (4.6%) than helminth species. The most prevalent parasite was the minute intestinal fluke Haplorchis taichui (35.9%). Amplicon sequencing of 16S rRNA was conducted to investigate the gut microbiome profiles of H. taichui-infected participants compared with those of parasite-free participants. Prevotella copri was the dominant bacterial operational taxonomic unit (OTU) in the study population. The relative abundance of three bacterial taxa, Ruminococcus, Roseburia faecis and Veillonella parvula, was significantly increased in the H. taichui-infected group. Parasite-negative group had higher bacterial diversity (α diversity) than the H. taichui-positive group. In addition, a significant difference in bacterial community composition (ß diversity) was found between the two groups. The results suggest that H. taichui infection impacts the gut microbiome profile by reducing bacterial diversity and altering bacterial community structure in the gastrointestinal tract.