Transactions of The Royal Society of Tropical Medicine and Hygiene最新文献

Background: The genus Acanthamoeba is reported from various environmental sources and can cause multiple complications, including chronic amoebic aeratitis and amoebic granulomatous encephalitis. This study investigated the presence and genotyping of Acanthamoeba in the soil of parks and patients with malignancies referred to health centers in Zanjan city, Iran.

Methods: In this cross-sectional study, 200 soil samples were collected from amusement parks in Zanjan city from September 2017 to May 2018. Samples were cultured on 1.5% non-nutrient agar, and the Acanthamoeba genus was identified using the morphological method. PCR was performed on all positive environmental samples, and six microscopically positive clinical samples belonged to our previous study. DNA sequencing of 18S rRNA was performed to analyze the genetic pattern of some PCR-positive isolates.

Results: Microscopic results showed that 96 (48%) soil samples were positive. PCR confirmed all positive cases of clinical samples and 84 soil samples. Out of the PCR-positive samples, 20 soil samples and five clinical samples were sequenced successfully. All soil isolates belonged to the T4 genotype, and three and two clinical samples belonged to T4 and T5 genotypes, respectively.

Conclusion: : The presence of Acanthamoeba in both the environment and clinical samples of Zanjan city suggests paying greater attention to the infections caused by it.

Background: Children are especially vulnerable to Toxocara infection and its severe complications; however, there have not been any published data on the disease prevalence and treatment effectiveness in the population of Vietnamese children. This study was conducted to determine the prevalence of toxocariasis and explore factors associated with Toxocara infection in children aged 3-15 y in Ho Chi Minh City, Vietnam.

Methods: We conducted a cross-sectional study using a multistage cluster sampling approach in public schools. Blood samples were collected, and toxocariasis cases were confirmed, based on a history of contact with dogs/cats and positive anti-Toxocara antibody detection via ELISA. We calculated the percentage of seropositive children across gender, grade levels, districts and caregiver education. Multiple regression models were employed to identify potential risk factors.

Results: Anti-Toxocara antibodies were found in 14.2% of the 986 children studied. Significant variations in seropositivity were observed across grade levels, districts and caregiver education levels. Multivariable analysis identified caregiver education, contact with dogs/cats and improper handling of pet feces as seropositivity risk factors.

Conclusion: This was the first community-based prevalence study of toxocariasis in a pediatric population in Vietnam. Implementation of preventive measures such as public education, routine fecal examinations and chemotherapeutic treatment of animals is highly recommended.

Background: It is well-documented that using immunosuppressive drugs such as corticosteroids or cytokine blockers in treating coronavirus disease 2019 (COVID-19) increases the risk of co-infections. Here we systematically summarized the cases of COVID-19-associated parasitic infections (CAPIs) in Iran.

Methods: From 19 February 2020 to 10 May 2023, all studies on Iranian patients suffering from CAPIs were collected from several databases using a systematic search strategy.

Results: Of 540 records, 11 studies remained for data extraction. In this research, most of the studies were related to Lophomonas and Toxoplasma. Of 411 cases of CAPIs, toxoplasmosis (385 [93.7%]) had the highest rate of infection among Iranian patients, followed by blastocystosis (15 [3.6%]), fascioliasis (4 [0.97%]), leishmaniasis (3 [0.7%]), lophomoniasis (3 [0.7%]) and strongyloidiasis (1 [0.2%]). In general, Blastocystis enhanced diarrhoea in patients with COVID-19. Lophomonas, Toxoplasma and Strongyloides increased the severity of COVID-19, but Fasciola decreased its intensity. Patients with a history of cutaneous leishmaniasis showed mild symptoms of COVID-19. Also, patients with a prior history of hydatid cysts were not affected by COVID-19.

Conclusions: Due to the similar symptoms of some parasitic diseases and COVID-19 and immunosuppressive treatment regimens in these patients that may cause the reactivation or recurrence of parasitic infections, early diagnosis and treatment are required.

Pesticide poisoning is a common medical emergency in the rural tropics, with significant associated mortality. Pesticide poisoning is an umbrella term that encompasses a wide variety of substances with differing clinical toxidromes and outcomes. Despite this, confirmation of the specific compound ingested is rarely performed. In this Lessons from the Field, we argue that pesticide-specific management is integral to optimise management. Using data from a quality improvement project in Chittagong, Bangladesh, we demonstrate that identifying the specific compound is possible in most patients through careful history taking and examination of the pesticide bottle. Identification of the specific compound is essential for anticipating and reducing complications, administering appropriate and timely management and reducing the length of hospital stay and cost of unnecessary medical intervention.

Background: Neglected tropical diseases (NTDs) affect millions of people in Africa, with Uganda bearing a significant burden. The World Health Organization (WHO) set a goal to reduce NTDs and improve access to diagnosis and management by 2030. However, NTDs have not been well integrated into primary healthcare in many countries, including Uganda, due to limited knowledge and resources among health workers. The study aimed to assess the readiness and capacity of primary healthcare centres to diagnose and manage soil-transmitted helminths (STHs) and schistosomiasis.

Methods: A cross-sectional quantitative study was conducted among 204 health workers in 20 health facilities in four districts bordering Lake Kyoga. In this study we evaluated health workers' knowledge of symptoms, diagnosis and management of STHs and schistosomiasis as well as the availability of resources and training.

Results: Our findings indicate that health workers have strong knowledge about STHs (86.76%), with lower knowledge levels regarding Schistosoma haematobium (59.72%) and Schistosoma mansoni (71.43%). Regarding resources and training, 95% of health facilities had laboratory services, but the majority lacked diagnostic equipment. Furthermore, only 17% of health workers reported prior training on schistosomiasis and related topics and only 25% had training on surveillance and reporting.

Conclusions: While health workers in eastern Uganda demonstrated a good knowledge base for some NTDs, there were knowledge gaps and challenges in training on surveillance and reporting mechanisms. Continuously building the capacity of health workers along with investing in diagnostic infrastructure is essential for improved NTD control and ultimately reducing associated morbidity and mortality in the region.

Background: in vitro susceptibility testing for the non-sporulating fungus Madurella mycetomatis is performed with a hyphal suspension as starting inoculum and a viability dye for endpoint reading. Here we compared the performance of four different viability dyes for their use in in vitro susceptibility testing of M. mycetomatis.

Methods: To compare the reproducibility and the agreement between the viability dyes 2,3-bis-(2-methoxy-4-nitro-5-sulfphenyl)-2H-tetrazolium-5-carboxanilide salt (XTT), resazurin, 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium salt (MTS) and luciferin, the in vitro susceptibilities of 14 genetically diverse M. mycetomatis isolates were determined for itraconazole and amphotericin B. The reproducibility, agreement, price and ease of use were compared.

Results: Each of the four dyes gave highly reproducible results with >85.7% reproducibility. Percentage agreement ranged between 78.9% and 92.9%. Resazurin was the most economical to use (0.0009 €/minimal inhibitory concentration [MIC]) and could be followed in real time. Luciferin omitted the need to transfer the supernatant to a new 96-well plate, but cost 6.07 €/MIC.

Conclusion: All four viability dyes were suitable to determine the in vitro susceptibility of M. mycetomatis against itraconazole and amphotericin B. Based on the high reproducibility, high percentage agreement, price and possibility to monitor in real time, resazurin was the most suited for routine in vitro susceptibility testing in the diagnostic laboratory in mycetoma-endemic countries. Because luminescence could be measured directly without the need to transfer the supernatant to a new 96-well plate, luciferin is suitable for drug-screening campaigns.

Lay summary: To determine the in vitro susceptibility testing in the non-sporulating fungus Madurella mycetomatis, a viability dye is needed for endpoint reading. In this study we tested the viability dyes XTT, resazurin, MTS and luciferin for their use in in vitro susceptibility testing. It appeared that they all could be used but there were differences in time to result and costs associated with them.

Background: Haemophagocytic lymphohistiocytosis (HLH) is a rare complication of dengue fever with potentially life-threatening consequences and high mortality. Therefore, this study aims to investigate the prevalence, management and outcome of HLH in dengue fever.

Methods: The major electronic databases, including PubMed, ScienceDirect and Ovid SP, were searched from inception until 31 January 2024 to identify relevant studies. Pooled prevalence and mortality were calculated using the random-effects generic inverse variance model with a 95% CI. All the statistical analysis was conducted using R programming.

Results: A total of nine studies with 157 patients with HLH, 576 patients with severe dengue and 5081 patients with dengue fever were included in this meta-analysis. The prevalence of HLH in severe dengue (22.1%, 95% CI 8.07 to 48.0%) was significantly higher than the prevalence in dengue fever (3.12%, 95% CI 0.37 to 21.9%). The prevalence of HLH in severe dengue was higher in the paediatric population (22.8%, 95% CI 3.9 to 68.4%) compared with the adult population (19.0%, 95% CI 3.0 to 63.9%). The overall mortality rate was 20.2% (95% CI 9.7 to 37.2%).

Conclusion: The prevalence of dengue-associated HLH was low in patients with dengue fever but is significantly higher in patients with severe dengue and a high mortality rate.

Background: Scrub typhus is highly endemic in northern Thailand yet awareness and knowledge are low. We developed a community engagement project to improve awareness in communities at risk of contracting scrub typhus.

Methods: We conducted a series of engagement sessions with healthcare workers and community health volunteers so they would, in turn, engage with their communities. We evaluated our activities by assessing the increase in scrub typhus knowledge, using a series of Likert-scale items and open-ended questions. Three to 6 months after the sessions, participants were followed up to collect their experiences training community members.

Results: Of 134 participants who took part in eight sessions, 87.3% were community health volunteers. Disease knowledge increased substantially after the sessions and was well maintained for up to 5 mo. Satisfaction was high and, through participant feedback, engagement materials were improved to be more useful to the communities. People with higher education had higher scores and retention.

Conclusions: Community engagement was shown to be an effective tool to develop and carry out health-promoting activities in a culturally and context-appropriate manner.

Background: Chagas disease is caused by Trypanosoma cruzi, whose genetic structure is divided into six discrete typing units (DTUs) known as TcI-TcVI. In the Yucatan Peninsula, Mexico, information regarding the DTUs circulating in wild mammals is scarce, while this is important knowledge for our understanding of T. cruzi transmission dynamics.

Methods: In the current study, we sampled wild mammals in a sylvatic site of the Yucatan Peninsula and assessed their infection with T. cruzi by PCR. Then, for infected mammals, we amplified and sequenced nuclear and mitochondrial T. cruzi genetic markers for DTU identification.

Results: In total, we captured 99 mammals belonging to the orders Chiroptera, Rodentia and Didelphimorphia. The prevalence of infection with T. cruzi was 9% (9/99; 95% CI [5, 16]), and we identified TcI in a Jamaican fruit bat, Artibeus jamaicensis. Moreover, we fortuitously identified Trypanosoma dionisii in another Jamaican fruit bat and detected an unidentified Trypanosoma species in a third specimen. While the latter discoveries were not expected because we used primers designed for T. cruzi, this study is the first to report the identification of T. dionisii in a bat from Yucatan, Mexico, adding to a recent first report of T. dionisii in bats from Veracruz, and first report of this Trypanosoma species in Mexico.

Conclusion: Further research is needed to enhance our knowledge of T. cruzi DTUs and Trypanosoma diversity circulating in wildlife in Southeastern Mexico.