BackgroundMalaria is a public health problem that affects remote areas worldwide. Climate change has contributed to the problem by allowing for the survival of Anopheles in previously uninhabited areas. As such, several groups have made developing news systems for the automated diagnosis of malaria a priority.ObjectiveThe objective of this study was to develop a new, automated, mobile device-based diagnostic system for malaria. The system uses Giemsa-stained peripheral blood samples combined with light microscopy to identify the Plasmodium falciparum species in the ring stage of development.MethodsThe system uses image processing and artificial intelligence techniques as well as a known face detection algorithm to identify Plasmodium parasites. The algorithm is based on integral image and haar-like features concepts, and makes use of weak classifiers with adaptive boosting learning. The search scope of the learning algorithm is reduced in the preprocessing step by removing the background around blood cells.ResultsAs a proof of concept experiment, the tool was used on 555 malaria-positive and 777 malaria-negative previously-made slides. The accuracy of the system was, on average, 91%, meaning that for every 100 parasite-infected samples, 91 were identified correctly.ConclusionsAccessibility barriers of low-resource countries can be addressed with low-cost diagnostic tools. Our system, developed for mobile devices (mobile phones and tablets), addresses this by enabling access to health centers in remote communities, and importantly, not depending on extensive malaria expertise or expensive diagnostic detection equipment.

The objective of this study is to assess the risk of newly acquired RNA detection-proven SARS-CoV-2 infection after previous SARS-CoV-2 infection. This is a prospective study conducted from March to September 2020 in Barcelona, Spain. Healthcare workers caring for SARS-CoV-2 infected patients were divided in two cohorts: (a) previously RNA-proven SARS-CoV-2 infected cohort with mild symptoms (IC) and (b) healthy cohort (HC). Weekly SARS-CoV-2 RNA detection assays from nasopharyngeal swabs were performed. Serology status was assessed at the beginning and at the end of the study. Twenty participants were included in each group. The median age was 30 (IQR 27–34.75) years, and 55% were female. The median time of follow up was 49 (IQR 49–51) days. Fifteen out of 246 (6%) nasopharyngeal swab samples were positive for SARS-CoV-2, all in the IC. The percentage of participants in the IC with a probable newly acquired SARS-CoV-2 RNA-proven infection was 20% (95% IC 5.7–43.6%) at the end of the 7-week follow up period. The incidence reinfection rate was 28.6 (95% IC 7.8–73.2) cases per 1000 person-week. Despite detectable IgG antibodies against SARS-CoV-2 participants highly exposed to SARS-CoV-2 may develop a newly acquired SARS-CoV-2 RNA detection episode during the first months after the initial infection.

Background Antitrypanosomal treatment with Benznidazole (BZ) or Nifurtimox may be recommended for patients with chronic Chagas disease (CD) to reduce the onset or progression of symptoms. However, such treatment has limited efficacy and high level of toxic effects. In addition, the current cure biomarker (serology conversion) precludes any treatment assessment unless a prolonged follow-up is arranged. PCR is thus the most useful, alternative surrogate marker for evaluating responses to treatment. The aim of this study is to describe the usefulness of real-time PCR in monitoring BZ treatment within a large cohort of chronic CD cases in Barcelona. Methodology/Principal findings A total of 370 chronic CD patients were monitored with real-time PCR post-BZ treatment. The median follow-up was 4 years (IQR 2.2-5.3y), with a median of 3 clinical visits (IQR 2-4). Only 8 patients (2.2%) presented with at least one incident of positive real-time PCR after treatment and were therefore considered as treatment failure. Four of those failure patients had completed full course treatment, whereas the remaining cases had defaulted with a statistical difference between both groups (p = 0.02). Half of the failure patients had undergone less than 4 years of follow-up monitoring all presented with parasitemia before treatment. Conclusions/Significance BZ treatment failure was highly infrequent in our cohort. BZ discontinuation was a risk factor for positive real-time PCR results during clinical follow-up. Regular testing with real-time

Background Trypanosoma cruzi has a high genetic and biological diversity and has been subdivided into seven genetic lineages, named TcI-TcVI and TcBat. DTUs TcI-TcII-TcV and TcVI are agents of ChD in different regions of Latin America. Due to population movements, the disease is an emergent global public health problem. Thus, the aim of this study was to quantify the parasitic load and identify the presence of T. cruzi DTUs in 101 Latin American immigrants with chronic ChD, residing in Barcelona, Spain. Methodology / Principal findings 5ml of peripheral blood were collected in guanidine/EDTA from each patient for DNA extraction, quantification of the parasitic load and genotyping. A great variation of the parasitic load of the patients was verified: from 0.001 to 22.2 T. cruzi DNA (fg) / Blood DNA (ng). In patients from Bolivia the parasitic load was 3.76±4.43 T. cruzi DNA (fg) / Blood DNA (ng) (mean ± SD), in patients of other countries was 0.95±1.38 T. cruzi DNA (fg) / Blood DNA (ng). No statistically significant difference was observed in the parasitic load between patients with the indeterminate and cardiac forms of ChD (p = 0,57). Parasite genotyping was performed by multilocus conventional PCR. In patients from Bolivia there was a nearly equal prevalence of DTUs TcV (27/77), TcII/TcV/TcVI (26/77), and TcII/TcVI (22/77). TcVI PLOS NEGLECTED TROPICAL DISEASES

It is known that the immunoregulatory networks in human Chagas disease play a key role in parasitemia control during the acute phase. However, little is known regarding the control of parasitemia during the chronic phase. The aim of the study was to describe the serum cytokine profile of Trypanosoma cruzi chronically infected patients and to evaluate its relationship with the presence or absence of parasitemia in peripheral blood. This is a prospective observational study where adult Chagas disease patients were included. Patients previously treated for Chagas disease, pregnant women, and immunosuppressed patients were excluded. Demographic and clinical information was collected, and T. cruzi real-time polymerase chain reaction (RT-PCR) and serum cytokine profile were determined in peripheral blood. Forty-five patients were included. Trypanosoma cruzi RT-PCR in peripheral blood resulted positive in 19 (42.2%) patients. No differences in the serum cytokine profile were found depending on cardiac or digestive involvement. However, patients with positive T. cruzi RT-PCR had a higher median concentration of IL-10 and IL-1beta and a lower median concentration of IL-8 than those with negative T. cruzi PCR. These results reinforce the key role that this antiinflammatory cytokine (IL-10) plays in parasitemia control.

Diagnosis of congenital malaria is complicated by the low density of the parasite circulating in the cord blood and/or the peripheral blood of the newborns. Molecular techniques are significantly more sensitive than blood smears in detecting low-level parasitemia. This study investigated the prevalence of congenital malaria by the use of the real-time polymerase chain reaction (real-time PCR) in 102 babies born to mothers with microscopically confirmed infected placenta from Blue Nile state, Sudan. At delivery time, placental, maternal peripheral and cord blood samples in addition to samples collected from the newborns’ peripheral blood were examined for malaria infection using Giemsa-stained thick smear and parasite DNA detection by real-time PCR. The overall prevalence of congenital malaria includes the total babies with cord blood parasitaemia and peripheral blood parasitaemia was 18.6 and 56.8% using microscopy and real-time PCR, respectively. Even though all the neonates were aparasitaemic by microscopy, 19 (18.6%) of the babies had congenital malaria detected by real-time PCR, 15 (25.9%) of the babies with congenital malaria were born to mothers with both placental and peripheral blood malaria infections detected using the two techniques. Congenital malaria was significantly associated with cord blood malaria infections, maternal age and maternal haemoglobin level (p < 0.001). This first study investigating congenital malaria in Blue Nile state, Sudan shows that malaria-infected placenta resulted in infant and cord blood infections.

Aim: To describe the molecular types of Treponema pallidum and the proportion of macrolide and tetracycline resistance mutations in Barcelona. Materials & methods: Molecular type was determined using the Enhanced-CDC Typing system and antibiotic resistance was determined by sequencing the 23S and 16S rRNA genes. Results: A total of 183 patients were enrolled and 213 specimens (99 ulcers, 114 bloods) were collected. Sixty-two (70.5%) of 88 ulcers and 0 (0%) of bloods T. pallidum-DNA containing samples were fully typed. Up to 21 different strain types were identified (14d/g in 27.4%; 14f/g in 14.5%). Macrolide resistance mutations were present in 95% and tetracycline in 0%. Conclusion: Several different strains co-exist in Barcelona with a high proportion of macrolide resistance and absence of tetracycline resistance.

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