Mahosot Hospital

Scrub typhus and murine typhus, caused by Orientia tsutsugamushi and Rickettsia typhi, respectively, are important causes of febrile illness in Laos. Although several studies have assessed rickettsial infection in selected provinces, the nationwide distribution remains unclear. This study aimed to estimate exposure to scrub typhus group (STG) and typhus group (TG) across twelve provinces of Laos and identify potential hotspots. We screened 1,200 serum samples from blood donors (100 per province) for STG and TG IgG antibodies using enzyme-linked immunosorbent assays (ELISA). Samples with optical density ≥ 0.5 were confirmed by immunofluorescence assays (IFA). Overall seroprevalence was 7.26% (95%CI:5.93-8.87) for STG and 4.09% (95% CI:3.11-5.37) for TG. STG seroprevalence was highest in Huaphan (27%), Oudomxay (19%) and Xiangkhuang (17%), all in northern Laos. TG seroprevalence was 10% in both Oudomxay (north) and Attapue (south). Compared with Vientiane Capital, these provinces had significantly higher seropositivity. No significant association was observed with age group. STG seropositivity was higher in males, whereas TG seropositivity was higher in females. Rickettsial infections are widespread in Laos, with STG seroprevalence concentrated in the north and TG seroprevalence present in both the north and south, guiding future research priorities and informing targeted public health interventions.

Murine typhus, caused by infection with Rickettsia typhi, is a neglected disease contributing to infectious disease burden in south- and southeast Asia. Despite its importance, we have minimal knowledge of the genomics of R. typhi, with only four complete genomes being sequenced prior to this work. We sequenced a further 25 genomes including historical strains collected before 1976 from both human and rat hosts, and recent genomes isolated from patients at a single hospital in Laos. Whole genome SNP analysis reveals extremely low levels of genetic diversity across the 29 genomes, with overall nucleotide diversity (π) of 1.27e-05 and evidence of purifying selection, and a minimal pan-genome. Phylogenetic analysis shows clustering of the genome by historic or modern origin, with the exception of one modern strain which is most closely related to historic strains from Thailand, and no clustering by host origin. The highly conserved genome of R. typhi suggests strong constraints on genome evolution in this obligate intracellular parasite, and has implications for the design of future murine typhus diagnostic tools and vaccines.

Abstract While the link between intra-familial Adverse Childhood Experiences (ACEs) and recidivism is increasingly supported by evidence, the underlying mechanisms explaining this relationship remain less explored. In the current study, we, for the first time, investigated the path from intra-familial ACEs to recidivism, with a focus on the mediating role of substance use among a sample of male prisoners in Tunisia. We conducted a cross-sectional survey in April 2023 among 403male adult prisoners with a median age of 31 [26; 40] years. Using a self-administered, anonymous questionnaire in Arabic, we asked about ACEs using the World Health Organization (WHO) ACEs questionnaire as well as substance use and criminal history. Participation in the study was voluntary. Mediation analyses investigate the indirect effect of an independent variable on a dependent variable through a mediator. We found that the most prevalent forms of intra-familial ACEs were physical abuse (74.6%) and emotional abuse (73%). Regarding substance use, 76.9% were smokers, 59.1% reported alcohol consumption and 52.1% used cannabis. Recidivism was observed in 52% in our sample, with 18% re-incarcerated twice and 34% at least three times. Mediation analysis indicated that substance use was a mediator between intra-familial ACEs and recidivism. Specifically, emotional neglect and physical abuse were found to mediate recidivism through substance use. These findings underscore the importance of addressing intra-familial ACEs and substance use in efforts to reduce recidivism among incarcerated individuals.

Ticks and fleas are vectors of medically important infectious diseases globally, such as Rickettsiae. These pathogens are frequently reported in Southeast Asia, including Laos; however, there are very few comprehensive reports on their prevalence and vector diversity in urban areas. This study collected ectoparasites from companion animals to assess pathogen prevalence and exposure risk. In five veterinary clinics across Vientiane capital, ectoparasites were collected from dogs and cats and identified to the species level using both morphological and molecular methods. Ectoparasite DNA samples were screened for bacteria (17-kDa and 16S rRNA gene). Ticks were submitted to evaluate the potential of MALDI-TOF mass spectrometry for species identification. A total of 3,771 arthropod vectors (3,658 ticks, 105 fleas, 8 lice) were removed from dogs and cats. Ticks were morphologically identified as Rhipicephalus sanguineus sensu lato (s.l.) tropical lineage (currently recognised as Rhipicephalus linnaei), whilst fleas were classified as either Ctenocephalides felis felis (57.1%) or C. f. orientis (42.9%) and lice were Heterodoxus spiniger. The MALDI-TOF spectra in this study revealed similar mass-to-charge (m/z) peak profiles to those reported in previous studies for Rhipicephalus sanguineus. Rickettsia spp. (Rickettsia asembonensis and Rickettsia felis) were detected in 44.4% of pooled flea samples collected from 12 dogs and 4 cats, as well as 3.5% of tick pools collected from 142 dogs and 50% of lice pools collected from 2 dogs. In addition, Anaplasmataceae (Ehrlichia canis and Anaplasma platys) were detected in 22.5% of ticks collected from dogs. This study highlights the diversity of ectoparasite species collected from dogs and cats and provide preliminary insights into the use of MALDI-TOF MS for tick species identification. While promising, further research is needed to enhance the reliability and efficacy of this approach. The findings also reveal a high prevalence of pathogens in ectoparasites, emphasizing the need for increased awareness among pet owners, veterinarians, and addressing public health concerns.

The Gram-negative bacterium Burkholderia pseudomallei causes a severe infectious disease known as melioidosis in humans and animals. It is considered endemic in tropical countries, including Thailand, Lao PDR (Laos), and Northern Australia. B. pseudomallei is a saprophyte found in contaminated soil and surface water. Humans and animals can become infected via direct exposure to contaminated water or soil and inhalation of dust or water droplets. Despite the high morbidity and mortality rates of melioidosis, there is a lack of knowledge of its geographical distribution and seroprevalence, even within endemic countries, raising a significant public health concern. For a better understanding of melioidosis in livestock in Laos, both as an animal health concern and as an indicator of human risk, we collected serum samples from an abattoir monitoring program for B. pseudomallei antibody testing using the Indirect Haemagglutination Assay (IHA). Out of the 917 sera collected, major findings included the identification of a significant cluster (p=0.041) in the southwest border region adjoining northeastern Thailand, in the province of Savannakhet in Laos. Sera collected in January 2020 had the highest B. pseudomallei seroprevalence (17.0%), and cattle had the highest seroprevalence (22.8%), followed by buffalo (19.7%) and swine (4.0%). The B. pseudomallei seroprevalence results among the common livestock species and the maps generated can assist with future monitoring, prevention, and detection of melioidosis in Laos.

ContextThe increase and global dissemination of antibiotic resistance limit the use of antibiotics to prevent and treat infections. Implementing antibiotic stewardship programs guided by local data on prescription profiles is a useful strategy to reduce the burden of antibiotic resistance. The aim was to determine the prevalence of antibiotic use and guideline compliance at Luang Prabang provincial hospital, Lao PDR.MethodsA point prevalence survey of antibiotics was conducted among hospitalized patients admitted to Luang Prabang hospital (204 beds) in Lao PDR on May 25, 2023. All patients presenting at 8:00 AM were eligible. Sociodemographic data, indications for antibiotic use, and antibiotic prescriptions were collected from medical records using a paper-based questionnaire and entered into an electronic platform following WHO methodology. The prevalence of antibiotic use was determined.ResultsOut of the 102 patients included, 60(58.8%) were undergoing antibiotic treatment, of which 33(55.0%) received combination therapy, and 7(10.5%) had two indications for antibiotic use. The highest prevalence was in the surgical ward (14/15, 93%) followed by general paediatrics (18/27, 67%). Out of the 100 antibiotic prescriptions, 47(47%) were for community-acquired infections, 26(26%) for surgical prophylaxis, 13(13%) for hospital-acquired infections and 5(5%) for medical prophylaxis. Twenty(20%) antibiotics were prescribed for obstetrics and gynaecology prophylaxis, 17(17%) for intra-abdominal infections, and 10(10.0%) for pneumonia treatment as well as bone, and joint infections. The main antibiotics prescribed were ceftriaxone 36(34.6%), metronidazole 18(17.3%), ampicillin 8(7.7%), and gentamicin 8(7.7%). Only 2(3%) samples were sent to the laboratory, one of which showed a positive culture for Escherichia coli Extended Spectrum β-Lactamase. According to the WHO Access Watch and Reserve classification, 55(52.9%) molecules belonged to the Access category, 47(49.1%) to the Watch category, and none to the Reserve category. Only 14.9% of antibiotic prescriptions were fully compliant with current guidelines.ConclusionThis study indicated a significant prevalence of antibiotic use and a very low compliance with guidelines at Luang Prabang provincial hospital, Lao PDR. This highlights an urgent need for comprehensive strategies at all levels to optimize antibiotic use in hospitals, emphasizing diagnostic improvements, and continued research to address the factors driving this excessive antibiotic usage and improve adherence to guidelines.

Background Listeria monocytogenes is a food-borne pathogen that is a rare cause of bacteraemia and meningitis in immunosuppressed patients, and carries a high mortality rate. Cutaneous manifestations of listeriosis are rare, and are usually associated with direct inoculation of the skin. Case A 41-year-old woman who initially presented to a hospital in Laos with appendicitis was diagnosed with disseminated listeriosis with cutaneous involvement. Intra-abdominal pathology probably contributed to bacterial bloodstream invasion. Initial treatment with meropenem was switched to ampicillin based on best practice, however our patient died 5 days after diagnosis. Conclusions This case highlights listeriosis as an important cause of mortality in low- and middle-income countries, exacerbated by poor availability of laboratory diagnostics and ineffective empiric antibiotic regimens. Improvements in food hygiene, surveillance, and increased laboratory capacity are important strategies to reduce rates of infection and clinical outcomes.