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

Background: Leptospirosis is a major cause of human disease in Fiji. However, the epidemiology is poorly defined. This study was conducted to determine the epidemiology of human leptospirosis in the Central Division and to characterize the largest urban outbreak in Fiji.

Methods: A retrospective study was conducted using routine leptospirosis surveillance data collected from 1 January 2012 through 30 June 2020. Descriptive analysis was performed to evaluate changes in demographic characteristics and incidence over time.

Results: A total of 2248 cases were reported over the 8.5-y study period. Average annual incidence was 73.9 cases per 100 000 population, with the annual incidence ranging from 45.6 cases per 100 000 population in 2012 to 177.2 cases per 100 000 population in 2019. Overall, most cases were indigenous Fijians (82.6%) and males (53.3%). The proportion of females increased steadily from 37.8% in 2012 to 50.3% in 2020. On 28 January 2019, an outbreak of leptospirosis was declared in the Central Division. During this outbreak, the proportion of female cases (50.5%) was higher and cases among Fijians of Indian descent also increased (18.3%).

Conclusions: Study findings demonstrate changes in the epidemiology of leptospirosis in the Central Division. Increasing incidence in urban settings and among population groups previously considered low risk (female and Fijians of Indian descent) indicates shifts in risk factors and transmission patterns that warrant review of existing measures and strategies for nationwide disease control.

Background: Unravelling the population genetic structure and dynamics of drug-resistant Plasmodium falciparum (Pf) strains is essential to adapt control strategies. Here, genetic and evolutionary patterns of P. falciparum chloroquine resistance transporter (Pfcrt) in Cameroon were analysed.

Methods: Blood samples from P. falciparum-infected individuals living in a coastal area (Douala) and North and Far North areas (Maroua, Mayo-Oulo, Pette) were PCR-amplified and genotyped for the Pfcrt gene. Single nucleotide polymorphism analysis, haplotype network, neutral evolution and genetic differentiation patterns of Pfcrt sequences were also performed.

Results: The wild-type CVMNK was dominant (97.1%) in the coastal area, while the resistance genotype CVIET (50-61.9%) was predominant in the North and Far North areas. The mutation 72S was significantly more often reported in asymptomatic infections (p=0.004) and submicroscopic parasitaemia cases (p=0.002). A signature of positive selection or population expansion was identified in Pfcrt sequences from Douala. The Pf populations from coastal, North and Far North areas were genetically differentiated.

Conclusions: This study suggests a return to chloroquine susceptibility geographically restricted in the coastal region. The high circulation of the genotype CVIET in North and Far North areas calls for investigations of factors contributing to the persistence of chloroquine-resistant strains.

Haemophagocytic lymphohistiocytosis (HLH) is a rare complication of rickettsial infections. We report a 50-y-old man from northern India who presented with fever, respiratory distress, altered sensorium and an eschar. Despite treatment with doxycycline, his condition deteriorated with multi-organ dysfunction. PCR and sequencing from the eschar confirmed Rickettsia conorii. Bone marrow examination, elevated ferritin and triglycerides, as well as an H-score of 224 confirmed HLH. The patient was treated with corticosteroids but succumbed to refractory ventricular arrhythmias. A high index of suspicion is essential in rickettsial infections that present with multi-organ dysfunction, as early recognition of HLH enables the prompt initiation of treatment of the underlying disease and adjunctive immunosuppressive therapy. [GenBank accession nos. U59728.1 and MZ779037.].

Background: Amoebiasis, caused by Entamoeba histolytica, is a major health concern in tropical regions like India. Stool microscopy, the primary diagnostic method, has limited sensitivity due to morphological similarities with Entamoeba dispar and Entamoeba moshkovskii, an emerging pathogen. This study evaluates the effectiveness of quantitative polymerase chain reaction with high-resolution melting (qPCR-HRM) in distinguishing these morphologically similar Entamoeba species.

Methods: The qPCR-HRM method was standardized using control strains of E. histolytica, E. dispar and E. moshkovskii. The assay was further evaluated on 150 stool samples, with species confirmation achieved through conventional PCR and Sanger sequencing.

Results: The melting peaks of E. histolytica and E. moshkovskii were at 80±2°C and 82±2°C, respectively, and for E. dispar at 69±2°C. The qPCR-HRM was able to detect as low as 10 fg of parasitic DNA. Of 150 stool samples, a total of 10 (6.6%) were found to be positive for E. histolytica, 13 (8.6%) for E. dispar and 7 (4.6%) for E. moshkovskii.

Conclusions: This study is the first to standardize qPCR-HRM for the detection and differentiation of Entamoeba species from India. The qPCR-HRM assay offers a sensitive, specific and cost-effective diagnostic tool, contributing to improved patient management.

Integrated vector management (IVM) is an effective strategy for reducing malaria transmission by combining various malaria vector control methods tailored to local contexts. The Web of Science, PubMed and Google/Google Scholar databases were used to gather studies related to IVM-based malaria control. This review synthesized findings from 14 studies published between 2009 and 2024 evaluating the impact of IVM on malaria control across different regions worldwide. The studies employed observational, quasi-experimental and cluster-randomized controlled trial designs, with outcome measures including malaria incidence, vector density, parasite prevalence, entomological inoculation rate and human biting rates. Integrated strategies consistently demonstrated greater effectiveness than single interventions, with six studies reporting statistically significant reductions in transmission (p<0.05) and several documenting notable declines in morbidity, mortality and entomological indicators. Longitudinal studies from Uganda, Ethiopia and Nigeria showed sustained reductions in malaria cases and vector populations, while large-scale programs in China and India illustrated the long-term success of coordinated, multisectoral IVM efforts. Emerging tools such as attractive targeted sugar baits, genetically modified mosquitoes and green-synthesized metallic nanoparticles offer more environmentally sustainable options. Combining traditional and innovative methods, IVM potentially provides a sustainable global malaria control and eradication solution.

Background: Kyasanur Forest Disease (KFD) is a tick-borne viral haemorrhagic fever endemic to southern India.

Methods: We present a case series of five PCR-confirmed patients with KFD who developed oral candidiasis. CD4 and CD8 T-lymphocyte counts were measured using flow cytometry alongside detailed clinical assessment.

Results: All five patients with candidiasis had CD4 counts <300 cells/µl, and four had CD8 counts <200 cells/µl. None had other known immunosuppressive conditions.

Conclusion: CD4 and CD8 lymphopenia are consistent and clinically relevant features among patients with KFD who developed oral candidiasis, suggesting transient mucosal immune suppression as a potential pathogenic mechanism.

One Health threats at the human-animal-environment interface involve zoonotic diseases that spread from animals to humans and may directly impact humans through their intake of food and water or from the environment. The function of One Health is to enhance collaboration, coordination, communication and capacity building among the human health, animal health and environmental sectors, to provide effective disease prevention and control programs and to identify recommendations and practical action plans. Information in this study was compiled from Google Scholar and PubMed to assess the success of the implementation of the One Health approach worldwide. This comprehensive literature review included only peer-reviewed articles published in English within the past 10 y that addressed One Health practices relevant to the Eastern Mediterranean Region. The latest data show that 75% of newly emerging infectious diseases have animal origins, that domestic animals or wildlife are the source of 60% of these pathogens and that animals are the source of 80% of pathogens that pose a bioterrorism threat. Thus the significance of the One Health approach remains ever more urgent to address and mitigate these threats. Country studies from India, Kenya, Pakistan, Qatar, Saudi Arabia, Uganda and Zambia showcased multisectoral coordination and collaboration through technical activities in epidemiological surveillance, emergency preparedness and response, joint leadership and risk assessment in response to an outbreak. The World Health Organization Regional Office of the Eastern Mediterranean has rolled out the One Health framework, with some degree of success in certain countries, in response to epidemics, disease prioritization or as a road map for collaboration. However, other countries in the region have yet to adopt the One Health approach. Overall, One Health has demonstrated its value in protecting animals, humans and the environment by pooling expertise from different fields to prevent and control future pandemics.

Background: Imported malaria is a threat to malaria elimination. A case investigation (CI) with reactive active case detection (RACD) strategy is commonly used for the detection of malaria infections around the index cases.

Methods: CI with RACD was conducted for detection of subpatent malaria among febrile mobile and migratory population (MMP) individuals around index cases in the state of Punjab in India, by microscopy, rapid diagnostic tests (RDTs) and nested PCR (nPCR). Glucose-6-phosphate dehydrogenase deficiency (G6PDd) was determined in Plasmodium vivax-positive patients.

Results: A total of 119 malaria cases were reported, out of which 93.3% were P. vivax (111/119) and 6.7% (8/119) were Plasmodium falciparum. CI with RACD was initiated around 28 MMP index cases positive by RDT and microscopy. A total of 176 fingerprick samples were collected from febrile MMP individuals, from which 11 (11/176; 6.3%) infected individuals were detected: eight by RDT, microscopy and nPCR, and three (3/11; 27.3%) subpatent cases by only nPCR. None of the positive patients were found positive for G6PDd.

Conclusions: Subpatent malaria in MMP individuals can pose a challenge in malaria elimination. The RACD strategy around index cases may help to reduce the risk of spillover in the local population.

Background: Haematological parameters and CD4+ T-cell count are used as indicators of disease severity and treatment response. Ethiopia is one of the cutaneous leishmaniasis (CL)-endemic countries. There is a scarcity of data on the haematological and CD4+ T-cell profiles of patients with CL in Ethiopia.

Methods: A cross-sectional study was conducted from April to July 2022. This study was conducted at Nefas Mewcha Hospital Leishmaniasis Treatment Centre. Patients with different clinical presentations of CL were recruited. The controls were from a non-CL endemic area and had neither symptoms nor history of CL. Demographic data were collected by a standardised questionnaire. Complete blood cell and CD4+ T-cell counts were determined by a MicroCC-20 Plus automated haematology analyser and BD FACSPresto, respectively. The data were analysed using SPSS-23 and Graphpad Prism 9.4.1. Statistical difference was considered at p<0.05.

Results: A total of 48 adult patients (41.7% female; median age: 28 [18-45] y) with CL and 31 controls were recruited. Most patients (62.5%) had localised CL. Whole blood levels, haematological parameters and CD4+ T-cell count were significantly lower in patients than controls. The median value of CD4+ counts was 734.5/mm³ in CL vs 867.0/mm³ in controls. There was no significant difference in all parameters between patients with different clinical forms.

Conclusions: Patients with CL had significantly lower levels of haematological parameters and CD4+ T-cell count.