Tropical Medicine & International Health最新文献

Introduction: Insecticide resistance in malaria vectors threatens the effectiveness of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) in Tanzania. Understanding the evolution of insecticide resistance is essential for guiding vector control policy in Tanzania. This review synthesises evidence on resistance patterns, surveillance and management strategies to inform programmatic decisions.

Objective: To synthesise evidence on insecticide resistance patterns, mechanisms and management strategies in Tanzanian malaria vectors (2015-2024), and to highlight research and surveillance gaps.

Methods: A scoping review was conducted using the PRISMA-ScR framework. Articles were retrieved from multiple databases based on predetermined eligibility criteria. Data on resistance patterns, mechanisms, surveillance approaches and management strategies were extracted and synthesised.

Results: Of 910 identified records, ten met inclusion criteria. All studies applied WHO susceptibility bioassays, and several incorporated molecular or biochemical assays. Pyrethroid resistance was consistently reported, largely driven by knockdown resistance (kdr) mutations and metabolic mechanisms. DDT resistance was common, while moderate resistance to carbamates appeared in about half of the studies. Organophosphates, particularly pirimiphos-methyl, remained effective and new insecticides such as clothianidin and chlorfenapyr showed high efficacy with no resistance detected. Reported management strategies included pyrethroid-PBO LLINs and integrated vector management, although surveillance coverage and mechanistic profiling were inconsistent across sites.

Conclusion: Insecticide resistance is widespread in Tanzanian malaria vectors, with pyrethroids most affected. While new insecticides and management strategies show promise, gaps in surveillance and operational evidence limit effectiveness. Strengthened research capacity, sustained funding and cross-sectoral collaboration are essential to support evidence-based resistance management and protect malaria control gains.

Addressing population health needs requires integrating indicators expressed on non-comparable scales, particularly for vaccination, a cornerstone of public health.

Objective: To propose and implement a Vaccination Needs Index based on national administrative data on tracer vaccines for children to support the prioritisation of Brazilian municipalities.

Methods: In this ecological study, we developed and applied a Vaccination Needs Index using national administrative data from 5570 Brazilian municipalities (2018-2022), integrating transformed and standardised indicators of vaccination coverage and the number of susceptible children for three tracer vaccines: diphtheria, tetanus, and polio (DTP) (third dose), polio (third dose), and measles, mumps, and rubella (MMR) (second dose).

Results: The estimated national coverages achieved in 2022 for the analysed vaccine doses were 79% for DTP, 67.7% for polio, and 46.1% for MMR. Consequently, approximately 3.0, 4.8 and 7.9 million children remained unvaccinated for these vaccines, respectively. When compared with criteria prioritising either unvaccinated children or low coverage alone, the top 5% of municipalities (n = 278) with the highest Vaccination Needs Index scores included a balanced mix of large, medium and small populations, with greater representation of the Legal Amazon region and Special Sanitary Indigenous Districts. These municipalities also had higher income inequality than the others, showing a mean difference in the Gini coefficient of 4.9 percentage points (95% CI: 4.2-5.7).

Conclusions: The Vaccination Needs Index effectively integrated absolute and relative vaccination indicators, identifying populations with intersecting vulnerabilities and socioeconomic inequities. It provides a practical and scalable tool to guide tailored interventions and optimise resource allocation, thereby preventing the resurgence of vaccine-preventable diseases.

Objective: Heart failure (HF) causes substantial morbidity, premature mortality and escalating healthcare costs, with prevalence rising fastest in low- and middle-income countries. Although guideline-recommended care can reduce mortality, its uptake remains suboptimal. We aimed to explore the roadblocks to optimal HF care in Kerala, a state in India with a high cardiovascular disease burden.

Methods: We conducted a convergent parallel mixed-methods study. We collected availability and price data of guideline-recommended HF medicines from 30 pharmacies (government-subsidised 6; private-retail 24) and diagnostics and interventional procedures from 4 private hospitals. Interviews (10 HF patients, 7 carers, 4 physicians and 4 policymakers) explored roadblocks to prevention, diagnosis and treatment.

Results: Mean availability of HF medicines was 45% in government-subsidised pharmacies and 66% in private pharmacies. Mean availability of HF diagnostics and interventional procedures was 89% and 57% in private hospitals. The lowest paid worker in Kerala would spend on average 0.3 days' wages to purchase a monthly supply of HF medicines in the government-subsidised pharmacies, and all but two HF medicines were affordable. The same worker would on average spend 1.4 days' wages for medicines in the private-retail pharmacies, 0.9 days' wages for cardiologist consultations, 8.4 days' wages for diagnostics and 1387 days' wages for interventional procedures. Interviews revealed care fragmentation, limited integration of HF management within broader programs, and gaps in patient and provider awareness.

Conclusions: We identified several roadblocks to optimal HF care at various levels of healthcare, mainly low availability, poor affordability and fragmented care. Addressing these roadblocks requires a multilevel coordinated effort among all health system actors to ensure equitable and effective HF care.

Background: Sexually transmitted infections, excluding HIV, continue to pose a major global public health burden, particularly amongst women of reproductive age. Despite strengthened global interventions, the distribution and trends of sexually transmitted infections vary significantly across regions and levels of the Socio-Demographic Index.

Methods: We analysed data from the Global Burden of Disease Study 2021 to assess the burden of sexually transmitted infections in 204 countries and territories from 1990 to 2021. Indicators included incidence, prevalence, mortality, and disability-adjusted life years, stratified by age, sex, and Socio-Demographic Index levels. Bayesian meta-regression was used to estimate the average annual percentage change for each indicator.

Results: Amongst women aged 15-49, the global sexually transmitted infections incidence rate increased from 13,847.22 to 14,701.69 per 100,000 person-years between 1990 and 2021 (average annual percentage change = 33.35, p < 0.001). Incidence rose for Chlamydial infection (average annual percentage change = 11.10), Genital herpes (average annual percentage change = 1.11), and Trichomoniasis (average annual percentage change = 34.76), but it declined for Gonococcal infection (average annual percentage change = -11.73). All burden indicators were negatively correlated with the Socio-Demographic Index (incidence: r = -0.541; disability-adjusted life years: r = -0.613; p < 0.001 for all). From 2022 to 2035, projections suggest a decrease in Chlamydial and Gonococcal infections, and a continued increase in Genital herpes and Trichomoniasis.

Conclusion: Sexually transmitted infections remain a pressing global issue for women of reproductive age, particularly in low- and middle-Socio-Demographic Index regions such as East Asia, sub-Saharan Africa, and Latin America. Enhanced sexual health education, broader access to care, and stronger surveillance systems are critical for reducing this burden.

Background: Group A β-haemolytic Streptococcus, also known as Streptococcus pyogenes, commonly causes childhood pharyngitis and can lead to severe complications like acute rheumatic fever and rheumatic heart disease. Timely penicillin treatment is vital in preventing these issues. However, data on the prevalence of Group A β-haemolytic Streptococcus pharyngitis in Botswana are limited, and there is no national surveillance for Group A β-haemolytic Streptococcus infections.

Objectives: This study aimed to determine the prevalence of Group A β-haemolytic Streptococcus pharyngitis among children aged 8 and 18 years presenting with sore throats in selected Gaborone clinics and assess the antibiotic sensitivity patterns of Group A β-haemolytic Streptococcus isolates.

Methods: A cross-sectional study was conducted among children aged 8-18 years suspected of pharyngitis at Nkoyaphiri and Mafitlhakgosi clinics in Gaborone. Participants were selected based on a modified Centor score of 2 or higher. Throat swabs were processed for culture, identification, and antibiotic sensitivity testing.

Results: The prevalence of Group A β-haemolytic Streptococcus pharyngitis was 7.5% (24/322; 95% CI: 0.50%-0.11%). The mean age of the participants was approximately 12 years. Group A β-haemolytic Streptococcus isolates remained fully susceptible to penicillin, the treatment of choice, but concerns about macrolide resistance were observed in some strains.

Conclusions: Group A streptococcal pharyngitis was found in 7.5% of children with sore throats in Gaborone, Botswana. All Group A β-haemolytic Streptococcus strains were susceptible to penicillin, affirming its continued use as the preferred treatment. These results emphasize the need for accurate diagnosis and targeted antibiotic therapy to prevent complications like acute rheumatic fever and rheumatic heart disease.

Objective: Malaria and anaemia are significant public health challenges among young children in Burkina Faso, with complex interactions between climate variability, food security, and nutrient deficiencies. This study aimed to identify the malariometric profile and nutrient patterns among young children and to determine the associations of nutrient patterns with clinical malaria and anaemia.

Methods: This cross-sectional study recruited 701 children aged 6-23 months in Nouna, Burkina Faso. Dietary intakes were collected using a semi-quantitative Food Propensity Questionnaire. Principal Component Analysis was used to derive nutrient patterns. We calculated logistic regressions for the associations of nutrient patterns with clinical malaria (Plasmodium species with fever (≥ 37.5°C) or a history of fever within the last 2 weeks or prescribed anti-malaria medication) and anaemia (Hb < 11 g/dL).

Results: In this study population (n = 452; median age: 17 months (interquartile range: 12, 21); male sex: 52%), 25.0% of the children had clinical malaria, and 88.5% had anaemia. Adherence to a 'fat and vitamin A' dietary pattern was inversely associated with the chance of clinical malaria (OR quintile 3 vs. quintile 1: 0.50, 95% CI: 0.26, 0.96) but not with anaemia. A 'fibre and micronutrient' pattern was neither associated with malaria nor with anaemia.

Conclusion: Anaemia is common in this malaria-endemic area, and diets characterised by fat and vitamin A may reduce the risk of clinical malaria in young children. This highlights the need for comprehensive management strategies addressing both malaria and anaemia, including community-based educational interventions to enhance complementary feeding practices in malaria-endemic regions.

Objective: Rapid diagnostic tests have been used mainly when it is not possible to carry out the recommended laboratory tests due to challenges derived from the infrastructure of the state surveillance system and, in the specific case of dengue, due to catastrophic climatic events that prevent the transport of samples. However, the performance of rapid diagnostic tests must be evaluated in the particular context of the population in which they are applied. We aimed to assess three rapid diagnostic tests used in Mexico for dengue diagnosis and epidemiologic surveillance.

Method: We used three rapid diagnostic tests that were compared to the RT-PCR/IgM capture ELISA construct as the gold standard. Additionally, the NS1-only results of the three rapid tests were compared to the RT-PCR test as the standard. A total of 125 plasma samples were randomly selected from febrile patients with suspected dengue who requested care between 2 and 6 days after the onset of fever.

Result: The best-performing test showed a sensitivity of 57.3% and a specificity of 100%. Regarding NS1 detection compared to RT-PCR, the best-performing test has a sensitivity of 84.4% and a specificity of 88.75%.

Conclusions: Although these tests can serve as an alternative to RT-PCR in emergencies, they should always be accompanied by a study that considers the history of predominant infection in the population and the circulation of serotypes.

Objective: The Trypanosoma cruzi immunopathology is sustained by a progressive inflammatory process triggered by parasite antigens, resulting in structural and functional changes in infected organs. Current etiological treatments of benznidazole and nifurtimox show limited efficacy and high toxicity, particularly during chronic infection stages. To address these limitations, a novel 3D printing formulation was applied to nifurtimox (3D nifurtimox) to improve its dissolution and reduce cytotoxicity. This study evaluated the therapeutic efficacy of 3D nifurtimox in experimental T. cruzi infection.

Methods: Female Swiss mice were infected with 4 × 10³ trypomastigotes of T. cruzi (Y strain) and treated orally for 28 days with nifurtimox (conventional or 3D) at doses of 25, 50 or 100 mg/kg or benznidazole 100 mg/kg. Survival rates, parasitemia and inflammatory profiles in cardiac and skeletal muscles were assessed through quantification of cytokines TNF, IL-6, CCL2 and IL-10.

Results: 3D nifurtimox at 50 and 100 mg/kg showed more efficacy in controlling blood parasites in mice surviving and regulating inflammatory cytokine patterns in cardiac and skeletal muscle tissues than conventional nifurtimox. In addition, 3D nifurtimox 100 mg/kg demonstrated complete parasite clearance and sustained protection even under immunosuppression. The improved efficacy is likely related to enhanced dissolution and bioavailability afforded by the 3D printing process, which transformed nifurtimox into an amorphous solid state.

Conclusion: 3D nifurtimox represents a promising new version of nifurtimox capable of being used in low doses with comparable or superior effects to benznidazole (100 mg/kg) and can be considered a promising tool for anti-T. cruzi therapies.