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Leishmaniasis poses a significant health burden, particularly among immunocompromised patients. In Thailand, Leishmania infection caused by Leishmania martiniquensis and Leishmania orientalis lacks information about the incidence and risk factors among HIV-infected populations. This longitudinal cohort study aimed to investigate the incidence and persistence of Leishmania infection among HIV-infected individuals in an affected area, Trang Province, Southern Thailand. The study also identified risk factors associated with the incidence of Leishmania infection. The study enrolled 373 participants in the HIV clinic, Trang Hospital, who initially tested negative for Leishmania infection during 2015–2016, and 133 individuals initially tested positive for Leishmania infection. Thus, follow-up visits of 506 participants occurred during 2018–2019. Direct Agglutination Test (DAT) and nested PCR (nPCR) identified incidents and persistent cases of Leishmania infection. Cox proportional-hazards regression analyses were performed to assess risk factors for the incidence of Leishmania infection. Among the initially negative group, 12 incident cases comprised one L. orientalis infection and 11 seropositive cases using DAT, resulting in a cumulative incidence of 3.2% and an incidence density of 10.38 per 1000 person-years. Increasing age was a significant predictor of the incidence of Leishmania infection. Five persistent cases comprised one Leishmania donovani complex and four seropositive cases using DAT in the initially positive group, with a cumulative persistence rate of 3.7% and a persistence density of 12.85 per 1000 person-years. All patients were asymptomatic. This study sheds light on the incidence and persistence of Leishmania infection among HIV-infected individuals in Trang Province, Southern Thailand, underscoring the importance of continued monitoring and tailored interventions to mitigate the impact of this co-infection. Author summary: In Thailand, Leishmania martiniquensis and Leishmania orientalis are the causative agents of cutaneous (CL) and visceral leishmaniasis (VL) reported in immunocompetent and immunocompromised individuals. VL poses a significant health threat, especially to those with HIV infection. Our study conducted a cohort study among HIV-infected patients in Trang Hospital, Trang Province, Southern Thailand, to explore the incidence and persistence of Leishmania infection, a topic not extensively studied in this region. Our findings are crucial for multiple reasons. Firstly, this study reveals a significant incidence rate of 3.2% among HIV patients, and increasing age was a significant predictor of incident Leishmania infection. Secondly, the persistence of Leishmania infection in 3.7% of initially positive cases underscores the challenges in managing this co-infection. It has immediate implications for healthcare providers, policymakers, and public health officials, aiding them in implementing targeted interventions and preventive measures to reduce the impact of leishmaniasis among HIV-infected individuals. By shedding light on this understudied issue, we hope to contribute to better health outcomes for this vulnerable population. [ABSTRACT FROM AUTHOR]

Leishmaniasis, a neglected tropical disease caused by parasitic protozoa of the Leishmania genus, remains a global health concern with significant morbidity and mortality. In Thailand, the rising incidence of autochthonous leishmaniasis cases involving Leishmania (Mundinia) martiniquensis and novel Leishmania (Mundinia) orientalis underscores the critical need for accurate diagnosis and effective control strategies. This study presents a sensitive and specific nucleic acid lateral flow immunoassay (NALFIA) that integrates a duplex PCR assay with a lateral flow device (LFD) strip format. Targeting the internal transcribed spacer 1 (ITS1) region, known for its unique combination of conserved and variable sequences, this assay employs primers labeled with biotin, digoxigenin, and fluorescein isothiocyanate (FITC) markers, enabling precise species identification and differentiation of these two Leishmania species. Remarkably, the assay achieves a sensitivity that surpasses agarose gel electrophoresis, detecting as few as 10−2 parasite/μL for L. martiniquensis and 10−4 parasite/μL for L. orientalis. Notably, the assay exhibited reliable specificity, revealing no cross-amplification with other major viscerotropic Leishmania species or reference organisms. Evaluation using 62 clinical samples further confirms the effectiveness of the PCR-LFD assay, with a sensitivity of 100% for L. martiniquensis and 83.3% for L. orientalis, and an excellent agreement (κ value = 0.948) with nested PCR. This integrated assay represents a promising advancement in diagnostic tools, offering rapid and accurate results that can significantly contribute to effective disease management and control. Given the increasing relevance of these Leishmania species in current public health scenarios, this assay serves as a valuable tool for both diagnostic and research applications. [ABSTRACT FROM AUTHOR]

To the Editor: Although rickettsioses caused by scrub typhus and typhus group rickettsiae are well recognized in Thailand, few spotted-fever group rickettsiae (SFGR), including Rickettsia honei TT118 and R. felis, [...]

Objective: To investigate the incidence, spontaneous clearance, persistence and risk factors of Blastocystis infection in a rural community in Thailand. Methods: In February 2016, a cohort study was conducted in a rural community of Thailand. Baseline information of intestinal parasitic infections and follow-up visits were conducted. Blastocystis infection was detected in stool samples examined with short-term in vitro cultivation using Jones' medium supplemented with 10% horse serum. Participants were tested for Blastocystis infection at every study visit. Cox proportional hazard regression analysis was used to evaluate co-variates to determine the incidence of Blastocystis infection. Results: Of 733 enrolled participants, 57 (7.78%) were positive and 676 (92.22%) were negative for Blastocystis infection. All 676 participants were followed-up for Blastocystis infection between December 2016 and January 2018. In all, 52 of 482 cases (10.79%) comprised individual Blastocystis infection. The incidence density rates of Blastocystis infection, of spontaneous clearance of the disease and of persistent infection were 8.13, 63.14 and 38.70 per 1 000 person-months of follow-up, respectively. Our multivariate analysis revealed that opened defecation in fields or bushes (HR=4.8; 95% CI =2.1-10.4, P <0.001), raising cows (HR=2.8; 95% CI =1.1-7.1, P =0.032), not washing hands after animal contact (HR=2.1; 95% CI =1.0-4.2, P =0.044) and presenting symptoms of nausea or vomiting (HR=2.3; 95% C/=1.0-5.3, P =0.047) were predictive associated risks for the incidence of Blastocystis infection. Conclusions: Our study indicates that the best way to prevent Blastocystis infection can be by maintaining good personal hygiene, hand washing after animal contact and improving sanitary facilities. [ABSTRACT FROM AUTHOR]

Background: In Thailand, artemisinin-based combination therapy (ACT) has been used to treat uncomplicated falciparum malaria since 1995. Unfortunately, artemisinin resistance has been reported from Thailand and other Southeast Asian countries since 2003. Malarone®, a combination of atovaquone–proguanil (ATQ–PG), has been used to cease artemisinin pressure in some areas along Thai–Cambodia border, as part of an artemisinin resistance containment project since 2009. This study aimed to determine genotypes and phenotypes of Plasmodium falciparum isolates collected from the Thai–Cambodia border after the artemisinin resistance containment project compared with those collected before. Results: One hundred and nine of P. falciparum isolates collected from Thai–Cambodia border from Chanthaburi and Trat provinces during 1988–2016 were used in this study. Of these, 58 isolates were collected after the containment. These parasite isolates were characterized for in vitro antimalarial sensitivities including chloroquine (CQ), quinine (QN), mefloquine (MQ), piperaquine (PPQ), artesunate (AS), dihydroartemisinin (DHA), ATQ and PG and genetic markers for drug resistance including the Kelch13 (k13), Plasmodium falciparum chloroquine resistance transporter (pfcrt), P. falciparum multidrug resistance 1 (pfmdr1) and cytochrome b (cytb) genes. Mean CQ, QN, MQ, PPQ and AS IC50s of the parasite isolates collected from 2009 to 2016 exhibited significantly higher than those of parasites collected before 2009. Approximately 57% exhibited in vitro MQ resistance. Approximately 94% of the isolates collected from 2009 to 2016 contained the pfmdr1 184F allele. Mutations of the k13 gene were detected in approximately 90% of the parasites collected from 2009 to 2016 which were significantly higher than the parasite isolates collected before. No ATQ-resistant genotype and phenotype of P. falciparum were found among the isolates collected after the containment project. Conclusions: Although the containment project had been implemented in this area, the expansion of artemisinin-resistant parasites did not decline. In addition, reduced sensitivity of the partner drugs of ACT including MQ and PPQ were identified. [ABSTRACT FROM AUTHOR]

The highly sensitive and selective determination of Escherichia coli (E. coli) in urine was achieved using a SYBR™ safe loop-mediated isothermal amplification (LAMP) method with a distance-based paper device. New primers set specific to multi-copy the 16s rRNA gene of E. coli were designed and used in this study. The detection sensitivity of these primers was higher than in related work and they could be incorporated with a low-cost paper-based device to quantify E. coli in urine at a concentration lower than 101 CFU mL-1. Regarding standard artificial urine, a linear range of a 10-fold dilution of E. coli concentration (105-100 CFU mL-1) with an R-square value (R2) = 0.9823 was observed directly using a fluorescent migratory distance of the 4 μL reaction mixture in the detection zone under blue light without the need for postreaction staining process. Based on the device, E. coli infection could be significantly categorized into 3 groups; none, light, and heavy levels, which is beneficial for UTI diagnosis. Hence, this paper-based device is suitable for use with the SYBR™ Safe-LAMP assay to semi-quantify E. coli, especially in resource-limited settings due to advantages of low cost, simple fabrication and operation, and no requirement for sophisticated instruments, as well as its disposability and portability.

Francisella is a genus of bacterial pathogens potentially lethal to humans. We report here for the first time a novel Francisella-like endosymbiont discovered in a hard-tick (Rhipicephalus sanguineus s.l.) obtained from a chicken (Gallus domesticus) in Thailand. The phylogenetic results indicate the 16S rDNA sequences of this Francisella bacterium form a unique clade with the Francisella-like endosymbiont of the tick species, Amblyomma varanense and Amblyomma helvolum, that have previously been found on snakes in Thailand. This species of Francisella is in a different group from the other Francisella-like endosymbionts previously reported from other countries. No Francisella was detected in Haemaphysalis wellingtoni ticks obtained from chickens in this study.