American Journal of Tropical Medicine and Hygiene最新文献

Nerve destruction is central to the pathogenesis and clinical manifestation of leprosy reactions (LRs). However, pathological changes in dermal nerves in LRs have not been clearly elucidated. Hematoxylin and eosin (H&E) staining may fail to accurately identify fragmented nerves, and special stains may be required. We recruited 56 patients with clinically diagnosed LRs as cases and 30 patients with nonreactional leprosy as controls. Number and level of nerves, nerve edema, relation of granulomas to nerves, perineuritis, pattern of nerve involvement, and quantification of each nerve pattern were noted on H&E stain and S-100 immunostain on skin biopsy sections. Most of the cases were borderline tuberculoid (BT; 32.8%) and lepromatous leprosy (32.8%) types, whereas most controls were classified as BT (44.8%). We found greater dermal nerve infiltration, fragmentation, and destruction during reactions when compared with nonreactional leprosy (fragmented nerves on S-100: P <0.0001). Nerve fragmentation (P = 0.037), subcutaneous nerve involvement (P = 0.014), and severe nerve edema (P = 0.0005) were higher in type 2 reaction (T2R) compared with type 1 reaction (T1R; on S-100), mostly attributed to the higher number of severe T2Rs (n = 23/25) among our cases. Intact nerves were higher in downgrading T1R compared with upgrading T1R (P = 0.038 on H&E and P = 0.004 on S-100). Thus, the identification and quantification of different patterns of nerves using special stains, such as S-100, may shed more light on nerve fiber involvement and destruction in LRs and may help us predict the prognosis of such cases.

Hispaniola, which is shared by Haiti and the Dominican Republic, remains the last island in the Caribbean that is still endemic for malaria, with Haiti bearing the highest caseload. Few studies have examined the ecology of malaria vectors in Haiti. Five species of Anopheles have been described on the island, but the exophilic Anopheles albimanus (An. albimanus) is considered the primary vector of malaria in Haiti. Households recruited for a case-control study profiling risk factors for symptomatic Plasmodium falciparum (P. falciparum) infections were approached to participate in an entomological study. The goal was to determine the bionomics of anopheline mosquitoes around the 32 participating households across varying malaria transmission settings. We assessed the characteristics of the Anopheles population using ultraviolet-light traps and larval surveys. Anopheles albimanus was the most abundant mosquito species identified in the Grand'Anse. Its abundance was higher in outdoor traps than in indoor traps and in areas with relatively high positivity based on rapid diagnostic test results. A greater proportion of blood-fed mosquitoes were found in higher transmission areas. Anopheles albimanus samples were found to be infected with both P. falciparum and Plasmodium vivax sporozoites. As Haiti aims for the elimination of malaria, disrupting localized residual malaria transmission will increasingly rely on focal vector control strategies.

We assessed the effect of active follow-ups on viral load (VL) suppression among people living with HIV (PLWH) who had missed their clinic visit(s) and were receiving intensive adherence counseling (IAC) at a large referral hospital in mid-western Uganda. We designed a quasi-experimental study, using a locator map (a local map showing residence) as an external factor (instrumental variable) that influenced active follow-up. We performed instrumental variable analysis. Of the 165 participants included, 24.8% had a client locator map, and possessing a map was associated with active follow-up (F-statistics 53.1; P <0.0001). Active follow-up did not significantly improve VL suppression at varying cutoffs, namely <1,000 copies/ml (P = 0.607), less than 200 copies/ml (P = 0.684), and less than 50 copies/ml (P = 0.435). Although active follow-up did not significantly improve VL suppression among PLWH on IAC, it showed a modest trend toward improvement. Large, randomized trials are needed.

Reports from endemic regions in Asia indicate that severe fever with thrombocytopenia syndrome virus (SFTSV), a canonically tick-borne virus, can be directly transmitted from infected humans and animals to naïve hosts. To understand this process, using a feline infection model, we observed that both intramuscular inoculation and oral inoculation resulted in adult cats developing viremia, with cats inoculated intramuscularly shedding virus orally. We also observed a potential organ tropism associated with the route of inoculation. Using an immunodeficient murine model, we further demonstrated that noncanonical routes of inoculation can result in lethal infections. However, we could not replicate the organ tropism seen in cats, possibly because of the immunodeficient nature of the mice. Like cats, mice shed SFSTV orally. These results indicate that SFTSV can exist in a vector-free cycle, highlighting a need for increased surveillance and precautions when handling potentially infected animals.

The WHO has a simplified grading system for assessing trachoma. However, even for experts, it can be difficult to classify certain cases as strictly positive or negative for a given grade. Given the absence of a true gold standard, we performed a Latent Class Analysis (LCA) on a set of 200 graded photos of the superior tarsal conjunctiva. Ten trained graders assessed the presence of two trachoma grades: trachomatous inflammation-follicular (TF) and trachomatous inflammation-intense (TI). The LCA was modeled in two different ways: first with two classes (presence/absence), and then with three classes, with the extra class presumed to represent a more discrepant "borderline" case. Cohen's κ-statistics measuring agreement between graders were calculated for TF and TI grades (separately) before and after removing the third latent class. The κ-statistic increased by 0.10 (95% CI = 0.72-0.85; P <0.001) for TF and 0.13 (95% CI = 0.81-0.90; P <0.001) for TI, indicating that the third latent class represented a discrepant-case borderline class. The identification of borderline grading cases using a three-class LCA may be useful in creating balanced grader certification examinations that represent the full spectrum of disease. Additionally, a multiclass LCA could act as a probabilistic gold standard used to train and analyze future convolutional neural network models.

Congregate settings are high-risk places for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission, making strategies that rely solely on hospital-based testing ineffective in curbing transmissions. We therefore evaluated the feasibility, utility, and acceptability of testing with SARS-CoV-2 antigen rapid diagnostic tests (Ag-RDTs) in markets and trade hubs in Kampala, Uganda. Between June and September 2022, we conducted a prospective operational research study in five divisions of Kampala. Four rounds of monthly cross-sectional surveys were conducted at one market and one trading hub per division, resulting in a total of 13,086 volunteers tested. Females were more likely than males to be tested (54% versus 46%), which aligns with sex-based differences in health-seeking behavior. More tests were conducted in markets (68%) compared with trade centers (32%). Several interventions increased overall demand for testing, including 1) awareness campaigns and mobilization activities; 2) the movement of teams across congregate settings; 3) the optimization of workflow; and 4) testing traders at their workstations. The overall positivity rate during the 4 months was 0.6% (78/13,086). There was a steady decline in positivity rates by month, aligning with the trend observed at the national level. Of the 78 positive index cases identified, 105 contacts were traced; 71% of these could be reached. None of the positive patients successfully self-isolated for the 14 days specified in national guidelines. Nevertheless, this study demonstrates that testing market dwellers with Ag-RDTs is not only acceptable and feasible in Uganda but also an important public health tool for the timely detection of SARS-CoV-2. This approach may be replicated in similar settings.

This prospective study was done to compare the initial presentation and treatment outcomes of tuberculosis among adult patients who have diabetes mellitus with those without diabetes mellitus. In this study, all adult patients (age 18 years old or older) with microbiologically confirmed drug-sensitive pulmonary tuberculosis who were put on treatment in Ballabgarh block in Haryana were enrolled. Information on clinical, radiological, and microbiological parameters at baseline was obtained by interview or record review. Symptom score was calculated by assigning one point for each symptom from zero to seven. Patients were followed for 6 months from the start of treatment to assess treatment outcomes. Data were analyzed using the χ2 or Fisher exact test. Logistic regression was used to assess the factors associated with death or unfavorable outcomes. In total, 412 patients were included in the study, of which 17.5% had diabetes mellitus. The mean symptom scores among those with and without diabetes were 3.7 (SD 1.3) and 3.6 (SD 1.4), respectively. Treatment success was achieved in 83.6% of patients with diabetes and 86.4% of patients without diabetes. Death was observed in 12.3% of patients with diabetes compared with 7.1% of patients without diabetes. There was no significant difference in clinical presentation, radiology, or sputum smear grade at baseline between patients with or without diabetes. Although treatment success rate was less and death rate was higher in patients with tuberculosis who had diabetes compared with those who did not have diabetes, the difference was not statistically significant.

A 27-year-old man presented with a cough and progressive limb weakness. Initially diagnosed with pulmonary tuberculosis, he showed improvement in his cough after antituberculosis treatment (ATT). However, he subsequently developed worsening weakness and numbness in his lower limbs, leading to mobility loss and difficulty swallowing. A comprehensive diagnostic evaluation, including computed tomography of the lung, cranial magnetic resonance imaging, cerebrospinal fluid analysis, and electromyography, confirmed concurrent diagnoses of tuberculosis (TB) and Guillain-Barré syndrome (GBS). Treatment included immunoglobulin and corticosteroid therapy; however, his symptoms persisted, progressing to respiratory failure that required endotracheal intubation and plasma exchange therapy. After these interventions, his condition gradually improved, and he continued ATT, achieving a favorable recovery. A literature review identified 15 countries reporting cases of GBS associated with TB, with the highest incidence in India. Although most cases showed a positive prognosis, mortality rates were elevated in patients with comorbid TB and GBS compared to those with GBS alone.

In September 2024, the US President's Malaria Initiative; the Global Fund for AIDS, Tuberculosis, and Malaria; the Gates Foundation; and Unitaid called for malaria partners to increase the availability and lower the cost of alternative artemisinin-based combination therapies (ACTs) for countries with growing evidence of resistance to artemisinin and current ACT partner drugs, particularly in sub-Saharan Africa. Although these global leaders should be applauded for raising this challenge to the highest levels, they missed the opportunity to highlight a major driver of resistance to malaria treatments: the limited access to high-quality health services for malaria. Progress has been made in scaling up integrated community case management and clinical and laboratory quality improvement programs, but few malaria-affected countries have achieved national scale. If affected countries and their partners do not want to confront resistance to these newer alternative ACTs in the near future, they must take more decisive action now to expand access and improve the quality of malaria services.