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Abstract. Strongyloides hyperinfection syndrome and disseminated strongyloidiasis frequently occur in immunocompromised persons and can lead to high complication and mortality rates. Thus, detection of Strongyloides stercolaris in those patients is crucial. The present study aimed to determine the prevalence of strongyloidiasis and compare the detection rates of different strongyloidiasis detection methods. We conducted a cross-sectional study of 135 adults with various immunocompromising conditions (corticosteroid usage, chemotherapy, hematologic malignancies, organ transplants, use of immunosuppressive agents, and symptomatic human immunodeficiency virus infection) in Phramongkutklao Hospital, Bangkok, Thailand. All patients were asked to undergo serology testing for Strongyloides IgG by indirect enzyme-linked immunosorbent assay (ELISA), and 3 days of stool collection for use in a simple smear along with formalin-ether concentration and agar plate techniques. Prevalence rates of strongyloidiasis were 5% by stool concentration technique, 5.4% by IgG-ELISA, and 6.7% by agar plate culture. Three of the eight strongyloidiasis cases in this study had hyperinfection syndrome. The tested risk factors of age, sex, occupation, and immunocompromising condition were not associated with Strongyloides infestation. Serology was only 42.9% sensitive (positive predictive value), but it was 96.3% specific (negative predictive value). In conclusion, prevalence rates of strongyloidiasis in this study were 5-7%. Although agar plate culture was the most sensitive technique, the other diagnostic methods might be alternatively used.

Acute undifferentiated febrile illness (AUFI) has been a diagnostic dilemma in the tropics. Without accurate point-of-care tests, information on local pathogens and clinical parameters is essential for presumptive diagnosis. A prospective hospital-based study was conducted at the Bangkok Hospital for Tropical Diseases from 2013 to 2015 to determine common etiologies of AUFI. A total of 397 adult AUFI cases, excluding malaria by blood smear, were enrolled. Rapid diagnostic tests for tropical infections were performed on admission, and acute and convalescent samples were tested to confirm the diagnosis. Etiologies could be identified in 271 (68.3%) cases. Dengue was the most common cause, with 157 cases (39.6%), followed by murine typhus (20 cases; 5.0%), leptospirosis (16 cases; 4.0%), influenza (14 cases; 3.5%), and bacteremia (six cases; 1.5%). Concurrent infection by at least two pathogens was reported in 37 cases (9.3%). Furthermore, characteristics of dengue and bacterial infections (including leptospirosis and rickettsioses) were compared to facilitate dengue triage, initiate early antibiotic treatment, and minimize unnecessary use of antibiotics. In conclusion, dengue was the most common pathogen for AUFI in urban Thailand. However, murine typhus and leptospirosis were not uncommon. Empirical antibiotic treatment using doxycycline or azithromycin might be more appropriate, but cost-benefit studies are required. Physicians should recognize common causes of AUFI in their localities and use clinical and laboratory clues for provisional diagnosis to provide appropriate treatment while awaiting laboratory confirmation.

We report a 50-year-old Thai woman with recent travel to Denmark who presented with acute high-grade fever, vomiting, and myalgia for 1 day. Initial laboratory results revealed leukopenia, elevated aspartate transaminase, and elevated alanine transaminase. Chest radiograph showed no pulmonary infiltration. Reverse transcriptase–PCR (RT-PCR) of the nasopharyngeal swab detected SARS-CoV-2, and RT-PCR of the blood detected dengue virus serotype 2. COVID-19 with dengue fever co-infection was diagnosed. Her symptoms were improved with supportive treatment. Integration of clinical manifestations, history of exposure, laboratory profiles, and dynamic of disease progression assisted the physicians in precise diagnosis. Co-circulating and nonspecific presentations of dengue infection and COVID-19 challenge the healthcare system in tropical countries. To solve this threat, multi-sector strategies are required, including public health policy, development of accurate point-of-care testing, and proper prevention for both diseases.

Differentiating dengue patients from other acute febrile illness patients is a great challenge among physicians. Several dengue diagnosis methods are recommended by WHO. The application of specific laboratory tests is still limited due to high cost, lack of equipment, and uncertain validity. Therefore, clinical diagnosis remains a common practice especially in resource limited settings. Bayesian networks have been shown to be a useful tool for diagnostic decision support. This study aimed to construct Bayesian network models using basic demographic, clinical, and laboratory profiles of acute febrile illness patients to diagnose dengue. Data of 397 acute undifferentiated febrile illness patients who visited the fever clinic of the Bangkok Hospital for Tropical Diseases, Thailand, were used for model construction and validation. The two best final models were selected: one with and one without NS1 rapid test result. The diagnostic accuracy of the models was compared with that of physicians on the same set of patients. The Bayesian network models provided good diagnostic accuracy of dengue infection, with ROC AUC of 0.80 and 0.75 for models with and without NS1 rapid test result, respectively. The models had approximately 80% specificity and 70% sensitivity, similar to the diagnostic accuracy of the hospital’s fellows in infectious disease. Including information on NS1 rapid test improved the specificity, but reduced the sensitivity, both in model and physician diagnoses. The Bayesian network model developed in this study could be useful to assist physicians in diagnosing dengue, particularly in regions where experienced physicians and laboratory confirmation tests are limited.

Strongyloides stercoralis is one of the common parasites in tropical areas. It can result in severe clinical syndromes, hyperinfection syndrome or disseminated strongyloidiasis in immunocompromised patients. The treatment of strongyloidiasis is a challenge for clinicians in clinical practice. Failure of treatment is due to autoinfection caused by the parasite life cycle and impairment of host immunity. Ivermectin currently is the treatment of choice. When compared with thiabendazole, it has shown a similar efficacy with better tolerability. However, there is neither consensus in duration of treatment nor in repetition of doses. The keys for management of this tough parasite include proper evaluation and prevention. Stool examination with high sensitivity techniques such as Baermann technique, filter-paper culture and agar-plate culture and specific IgG serology should be used in evaluation for 1 to 2 years. Screening, both stool examination and serology, before patients have immunosuppressive treatment is needed to prevent the severe form of strongyloidiasis.

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SummaryBackgroundThe emergence of highly pathogenic avian influenza H5N1 viruses has raised concerns about their pandemic potential. Vaccination is the most effective way of preventing influenza. In this study, we investigated the safety and immunogenicity of an avian H5N2 live attenuated influenza vaccine (LAIV H5N2) in healthy Thai adults and its priming immune responses with an H5N1 inactivated vaccine boost.MethodsThis study was done at the Vaccine Trial Centre at Mahidol University, Bangkok, Thailand and was divided into two parts. Part 1 consisted of a randomised, double-blind, placebo-controlled trial done over 18 months. We randomly assigned (2:1) healthy Thai adults aged 18–49 years with a computer generated randomisation sequence (blocks of six) to receive either two intranasal doses (0·25 mL per nostril) of LAIV H5N2 (101 participants) or placebo (51 participants) 21 days apart. For part 2, an open-label trial was done in which previously vaccinated participants (40 from LAIV H5N2 group and 20 placebo) were given one intramuscular dose (0·5 mL) of H5N1 booster vaccine. Participants, investigators, and site-study workers were blinded from randomisation. Immune responses after subsequent immunisation were evaluated using haemagglutination-inhibition and microneutralisation assays and circulating follicular T-helper cells and plasmablast cells were measured in serum and whole blood. The trials are registered with ClinicalTrials.gov, numbers NCT01841918 and NCT02229357.FindingsBetween Feb 4, 2013, and Feb 28, 2013, 256 individuals were screened, of whom 152 participants were enrolled in part 1 of this study. LAIV H5N2 vaccine was well tolerated. Viral shedding was detected in only six (6%) of 101 participants in the vaccine group 1 day after the first vaccination and in and two (2%) of 98 participants in the group after the second vaccination. There was no serious adverse event in both groups. 51 (50%) of 101 participants in the vaccine group and 28 (55%) of 51 in the placebo group reported at least one adverse event. 80 (84%) of 95 events in the vaccine group and 32 (78%) of 43 events in the placebo groups were reportedly suspected adverse events, probably related to the vaccine; however, most were mild in nature. After two doses of vaccine, 13 (13%) of 100 participants in the vaccine group had an increase in haemagglutination-inhibition titre of more than four-fold and four (4%) of 100 vaccinees developed a rise in neutralisng antibody titre of more than four-fold. 1 year later, after a booster with an inactivated H5N1 vaccine (part 2), 39 (98%) of 40 participants who had previously been vaccinated with LAIV H5N2 had an increase in haemagglutination-inhibition titre of greater than four-fold as early as day 7 compared with three (15%) of 20 participants in the placebo group. Peak geometric mean titre (GMT) for haemagglutination-inhibition antibodies in the previously LAIV H5N2 vaccinated group (566·89 [95% CI 436·97–735·44]) were significantly higher than among those who previously received placebo (25·4...