American Journal of Tropical Medicine and Hygiene最新文献

Soil-transmitted helminth (STH) infections rank among the most prevalent communicable diseases of humans, yet detection of these parasites is mostly restricted to identifying active infection through fecal examinations. Currently, there are no commercial diagnostic tools to identify a prior whipworm or hookworm exposure, and the few serological assays for roundworm infection have not been well validated for crossreactivity or infections in humans. Such diagnostic restrictions limit the range of scientific and clinical questions that surround STH exposures and their implicated relationship to chronic diseases, such as autoimmunity, allergy, and cancer. The goal of this investigation was to evaluate the diagnostic potential of 13 STH recombinant proteins. As there are no gold standard tests to verify positive STH antisera, we used sera from active STH-infected individuals in Honduras (measured by quantitative real-time polymerase chain reaction of helminth DNA in stool) and compared antibody recognition by both ELISA and western blot with nonendemic control sera from age-matched individuals in the United States split into screening and validation cohorts. One recombinant protein, rTm-WAP49, shows potential as a whipworm diagnostic tool by receiver-operator characteristic analysis (area under the curve = 0.997, P <0.001) and indirect ELISA with sensitivity of 100% and specificity of 91% as defined by mean plus two SDs from the nonendemic screening cohort. We found discrepancies in serological recognition of previously tested STH antigens, highlighting the need to consider different technologies before down selection of a promising diagnostic candidate and screen multiple endemic populations before widely accepting an STH serological assay.

Acute febrile illnesses (AFIs) with thrombocytopenia, such as dengue, leptospirosis, and scrub typhus, are often associated with bleeding and present challenges in transfusion therapy during outbreaks. Conventional bleeding predictors, which involve platelet counts, do not assess clot strength or fibrinolysis defects and may lead to inappropriate or delayed transfusions. To predict bleeding, we aimed to create a scoring system using point-of-care thromboelastography (TEG) and other conventional coagulation parameters. In this prospective cohort study, patients with AFI and platelet counts <100,000/cu mm who presented to the emergency department were recruited, and samples were collected for conventional coagulation tests and TEG analysis at admission. Patients were monitored for 48 hours for bleeding events, blood product transfusions, and mortality within 7 days. Receiver operating characteristic curves were plotted for significant predictors identified in univariate analysis, and a scoring system was generated using stepwise logistic regression. Sixty-six patients were recruited, including 38 with dengue and 11 with leptospirosis. Nineteen patients experienced a bleeding event within 48 hours. Dyspnea and elevated aspartate transaminase levels were more prevalent among those who bled. Thromboelastography parameters (reaction time/maximum amplitude [R/MA]), prothrombin time, international normalized ratio (INR), and baseline platelet count were significant predictors of bleeding. A scoring system using R/MA, INR, and platelet count achieved an overall predictive accuracy of 83.3% for 48-hour bleeding, with a score ≥3 demonstrating a sensitivity of 68% and specificity of 77%. Thromboelastography in patients with dengue showed more significant coagulation abnormalities than in those with leptospirosis. Validation in larger, more homogeneous populations is necessary.

Fascioliasis, which is caused by Fasciola hepatica and Fasciola gigantica (F. gigantica), is a public health problem worldwide. Stages infective to humans occur on aquatic plants and in water. The gold standard for diagnosing human infection depends on finding fluke eggs in stool samples. However, this method has low diagnostic sensitivity; eggs from other trematode species might be misidentified as those of Fasciola, and eggs are not voided in ectopic infections. Therefore, serological analysis can support the diagnosis of human fascioliasis. We evaluated whether a new fascioliasis immunochromatographic test kit, which detects specific IgG antibodies using F. gigantica excretory-secretory antigen, can be used for rapid diagnosis from whole blood. The kit ("the fascioliasis whole-blood test kit") was evaluated under laboratory conditions using 250 whole-blood samples (WBSs), of which 41 were from fascioliasis cases. Results based on simulated WBSs and the corresponding serum samples were compared and showed almost perfect agreement (percent agreement = 97.2%; kappa value = 0.9145). The diagnostic sensitivity and specificity of the test using simulated WBSs were 97.6% and 96.2%, respectively. Comparable values when serum samples were tested were 100.0% and 93.3%, respectively. This kit represents a significant advance because it does not require extensive training of personnel, is easy to use, and can support diagnosis at the bedside or in local and remote hospitals with limited facilities. The kit may also contribute significantly to epidemiological surveys.

Environmental enteric dysfunction (EED) is a subacute syndrome characterized by increased intestinal inflammation and permeability that affects children in low-income countries. It is associated with growth and neurodevelopmental deficits, and there is currently no known treatment for EED. VS001 (AmiLyfe Bioscience, LLC, Norwood, MA) is a medical food (beverage) containing free amino acids that has been shown to decrease enteric inflammation and improve gut permeability in murine models. We conducted a double-blind, placebo-controlled pilot study to assess the acceptability and tolerability of VS001 in Bangladeshi children aged 1-2 years (n = 10 per arm). We also examined the effects on EED biomarkers (lactulose-mannitol (LM) ratio, fecal lactoferrin, alpha-antitrypsin, myeloperoxidase, and neopterin). Participants received 8 oz. of VS001 or an identical vehicle without amino acids daily for 14 days. Tolerability and acceptability were measured using parental surveys and daily in-home adverse event monitoring. Subjects took an average of 118 minutes to complete the dose each day. Caregivers found the product convenient and easy to administer and either agreed or strongly agreed that they would give this product to their child again. None reported that the intervention negatively affected their child's appetite. There were three mild adverse events deemed possibly related to the intervention, with two occurring in the active arm and one in the control arm. Children in the active arm exhibited a nonsignificant decrease in LM ratios (a marker of intestinal permeability) after treatment compared with the control arm (0.19-0.08 versus 0.19-0.17; P = 0.16). VS001 was acceptable to parents and reasonably well tolerated. Given the decrease in permeability observed in the active arm, a larger trial is warranted.

There is uncertainty regarding the usefulness of predictive models for dengue prognosis. We performed a systematic review to identify and evaluate prognostic models in patients with dengue. We conducted a literature search in PubMed, Embase, and Literatura Latinoamericana y del Caribe en Ciencias de la Salud (LILACS) up to May 24, 2023. We included case-control and cohort studies that developed or validated multivariable prognostic models related to severity, hospitalization, intensive care unit (ICU) admission, or mortality in patients of any age with a laboratory-based diagnosis of dengue. A narrative synthesis of the performance measures of the prognostic models evaluated in each study was performed. Of the 4,211 articles, a total of 35 studies reporting information on 43 prognostic models were included. Among these, 35 were developmental and 8 were for external validation. Most models were designed to predict severity (n = 30), followed by mortality (n = 10), hospitalization (n = 2), and ICU admission (n = 1). The reported C-statistic in the models ranged from 0.70 to 0.95 for severity, 0.83 to 0.99 for mortality, 0.87 for hospitalization, and 0.92 for ICU admission. Calibration measures were poorly reported in the vast majority of models. According to the Prediction Study Risk of Bias Assessment Tool, the risk of bias was considered high for all included models, and applicability was of low concern for most models. Our study identified multiple prognostic models, particularly for predicting severity and mortality in patients with dengue. Although most models demonstrated acceptable discriminative ability, calibration measures were poorly reported, and the overall methodological design was poor.

Leeches, which are bloodsucking annelids widely distributed in natural environments globally, can cause hirudiniasis when they invade the human body. The most common site of infestation in humans is the nasopharynx, although they can also infiltrate less common sites, such as the trachea, esophagus, and urinary and reproductive tracts. We present the case of a 47-year-old male patient with a persistent cough for 2 months associated with hemoptysis and intermittent hoarseness for 1 month. Nasopharyngoscopy revealed an actively moving worm located above the vocal cords. Subsequently, under intravenous anesthesia, we removed the live worm through bronchoscopy, and it was identified as a leech. In areas where hirudiniasis is endemic, the possibility of tracheal leech infestation should be considered in patients presenting with chronic cough, hemoptysis, and hoarseness. Furthermore, it is crucial to take necessary precautions during outdoor activities to prevent the occurrence of hirudiniasis.

Plasmodium vivax (P. vivax) malaria is typically considered a benign form of malaria, with fewer life-threatening complications compared with Plasmodium falciparum. However, emerging evidence suggests that P. vivax can also lead to severe manifestations, including cardiac involvement. Myocarditis, although rare, is one such complication that can result in significant morbidity. This case report presents an 18-year-old man from Western India, with no previous comorbidities, who developed myocarditis secondary to P. vivax malaria. The patient initially presented with fever, chills, and headache, followed by the onset of hypotension, lactic acidosis, and cardiac complications, including a reduced left ventricular ejection fraction and elevated cardiac biomarkers. Despite requiring vasopressor support and oxygen therapy, the patient made a full recovery after receiving appropriate antimalarial treatment. This case underscores the need for heightened awareness of rare but serious complications, such as myocarditis, in patients diagnosed with P. vivax malaria.

Zika virus (ZIKV) is a flavivirus transmitted primarily by the bite of infected Aedes species mosquitoes. Although typically asymptomatic or causing mild symptoms and infrequent neurological disease in older children and adults, infection during pregnancy can result in severe congenital malformations and neurodevelopmental deficits. We conducted a review of published literature and official data sources to describe recent Zika epidemiological trends, building on WHO updates posted in 2019 and 2022. Globally, cases declined after the height of ZIKV transmission in the Americas in 2015-2016; however, transmission continues across multiple regions, with intermittent outbreaks reported. As of December 2023, there is documented evidence of current or prior autochthonous mosquito-borne ZIKV transmission in 92 countries and territories; most recently, Guinea, Mali, and Sri Lanka were included on the basis of recent or retrospective testing of specimens collected during surveillance activities or studies. The abundance of asymptomatic and mild infections and limited diagnostic testing suggest that transmission in many locations likely remains underrecognized. Public health authorities, clinicians, communities at risk, and travelers should remain alert to the possibility of ZIKV transmission and implement measures to limit the risk of infection with ZIKV and other Aedes-borne arboviruses. To strengthen surveillance for ZIKV infections and congenital disease, targeted surveillance using clear case definitions and epidemiologically appropriate laboratory testing algorithms should be applied.

Cutaneous leishmaniasis (CL), a parasitic disease caused by Leishmania aethiopica, is a major health problem in Ethiopia. It presents mostly as three different clinical forms: localized CL characterized by small lesions that ulcerate; diffuse CL defined by multiple nonulcerating nodules; and mucocutaneous leishmaniasis, where the mucosa of the nose or the mouth is affected. The mechanisms resulting in the development of these different clinical presentation are still poorly understood. Here, we recruited a cohort of CL patients presenting with different forms of CL in northwest Ethiopia as well as cohort of healthy nonendemic controls. We assessed the capacity of whole blood cells from these cohorts to produce cytokines in response to soluble L. aethiopica antigen and compared these levels between the different clinical presentations of CL and healthy nonendemic controls. Our results show that the levels of antigen-specific cytokines produced by whole blood cells from CL patients were higher as compared with controls. However, these cytokine levels were similar among the different clinical presentations. In conclusion, the results of our study indicate that variations in clinical manifestations of CL are not associated with differences in antigen-specific cytokine profiles.

Cryptosporidium spp. is a cause of diarrhea morbidity and mortality in children under 5 years of age. In addition, asymptomatic infections can have a negative impact on growth and development. In low- and middle-income countries where a greater number of infants may be malnourished, the results of treating cryptosporidiosis with the only Food and Drug Administration-approved drug nitazoxanide (NTZ) have been inconsistent. Malnutrition is both a risk factor for cryptosporidiosis and a consequence of infection with this parasite. Treatment with the probiotic Lactobacillus reuteri DSM 17938 has been shown to assist in nutritional recovery and the restoration of gut health. In this pilot randomized clinical trial, we examined whether combined probiotic and NTZ treatment could result in the reduction in parasitemia and infection-associated growth stunting in undernourished children. Cryptosporidium spp.-positive Bangladeshi children with a weight-for-length Z score between -1 and -3 were randomly assigned to one of three groups. Group 1 (n = 26) received NTZ and Lactobacillus, group 2 (n = 28) received NTZ along with a placebo, and the third control group (n = 10) received standard care. There was no difference in the duration of infection or improvement in child anthropometric measurements in any treatment group compared with control. Therefore, this pilot study does not provide support for treatment with NTZ, Lactobacillus, or the two in combination as an effective means of reducing the duration of Cryptosporidium spp. infection or improving growth in growth-stunted children.