Korelasi Temuan Limfosit Plasma Biru dengan Kadar C-Reaktif Protein sebagai Penunjang dalam Diagnosis Demam Berdarah Dengue

Dengue Hemorrhagic Fever diagnosis is supported by examining Blue Plasma Lymphocytes and C-Reactive Protein, in which Blue Plasma Lymphocytes can distinguish Dengue and Non-Dengue infections. At the same time, the C-Reactive Proteins are used to see the presence of inflammation due to infections such as Dengue Virus infection. Objectives: To analyzed the correlation of the number of Blue Plasma Lymphocytes with C-Reactive Protein (CRP) levels in Dengue Hemorrhagic Fever patients. Methods: This study was analytical observational research with a cross-sectional design. The sample used was a patient diagnosed with DHF with a positive Nonstructural protein 1 (NS1) or Rapid Diagnostic Test (RDT) IgG/IgM result. The data was collected and analyzed using Spearman's rank statistical test. Results: The average number of Blue Plasma Lymphocytes in positive samples was 8%, with the number of negative results, namely 4 (13.33%) samples and 26 (86.67%) samples with positive Blue Plasma Lymphocyte results. The average level of C–Reactive Protein in the positive samples was 29.36 mg/L, with results that had normal levels were 11 (36.67%) samples and 19 (63.33%) samples with abnormal C-Reactive Protein levels. Spearman's Rank statistical test results obtained a value of p = 0.000 < 0.05, indicating a correlation between the number of Blue Plasma Lymphocytes and C–Reactive  Protein levels in Dengue Hemorrhagic Fever patients. Conclusion: The more Blue Plasma Lymphocytes, the higher C–Reactive Protein levels in Dengue Hemorrhagic Fever. Keywords: blue plasma lymphocytes, C–reactive protein, dengue hemorrhagic feve

Infectious Etiologies of Febrile Illnesses in Cameron.

Ph.D. Thesis. University of Hawaiʻi at Mānoa 2017

Evaluations of Diagnostic Tests for Undifferentiated Febrile Illness on the Thailand-Myanmar (Burma) Border

Background Dengue, leptospirosis and rickettsial infections are the most common non-malaria causes of acute undifferentiated febrile illness in Southeast Asia. Current diagnostic tests are inadequate for clinical use. Methods We conducted a two year prospective fever study in three outpatient clinics on the Thailand-Myanmar border, recruiting patients aged at least five years with acute undifferentiated febrile illness. The study was divided into two parts: non-malaria and malaria patients. Specimens were tested to determine the causes of fever and to evaluate the clinical diagnostic accuracy of the tests for early diagnosis of dengue, leptospirosis and rickettsial infections. Results A total of 1,029 febrile patients were recruited: 908 non-malaria and 121 malaria patients. A laboratory confirmed diagnosis was made in 34.5% of non-malaria patients, of which 15.9% were dengue, 6.0% leptospirosis, 6.0% murine typhus, and 3.2% scrub typhus. Co-infection was found in 1.7% with mostly leptospirosis and scrub typhus (1.5%). In malaria patients, co-infection was found in 8.3% in most cases with scrub typhus (7.4%). An immunochromatographic test (ICT) (Non-structural protein 1 [NS1] and Immunoglobulin M [IgM]/Immunoglobulin G [IgG] detection) and real-time reverse transcriptase polymerase chain reaction (rRT-PCR) were evaluated for dengue diagnosis using acute plasma specimens. Sensitivities of the ICT and rRT-PCR were 86.1% (95% confidence interval [CI] 79.4-91.3) and 97.2% (95% CI 93.0-99.2), and specificities were 94.9% (95% CI 93.0-96.4) and 99.1% (95% CI 98.1-99.7), respectively compared against IgM/IgG enzyme-linked immunosorbent assay (ELISA). Combining rRT-PCR with ICT improved the sensitivity of the diagnostic process to 98.6% (95% CI 95.1-99.8). The IgM ICT and 47kDa quantitative real-time PCR (qPCR) for scrub typhus and 17kDa qPCR for murine typhus were evaluated using acute plasma specimens for the IgM ICT and acute buffy coat specimens for the qPCRs. Sensitivities of the IgM ICT, 47kDa qPCR and 17kDa qPCR were 27.3% (95% CI 15.0-42.8), 22.7% (95% CI 11.5-37.8) and 31.5% (95% CI 19.5-45.6) respectively. Specificities of the IgM ICT, 47kDa qPCR and 17kDa qPCR were 93.5% (95% CI 91.5-95.1), 99.6% (95% CI 98.9-99.9) and 99.7% (95% CI 99.0-100), respectively compared to IgM ELISA/indirect immunofluorescence assay (IFA). A 16S rRNA qPCR was validated and implemented for leptospirosis diagnosis. The analytical performance was good, it was found to be 100% specific and had a limit of detection of one copy per microliter (μl) of DNA template. Sub-microscopic malaria infection detected using 18S rRNA qPCR was found in 17.5% of non-malaria patients. The geometric mean of parasitaemia was very low (281.1 parasites/μl [95% CI 172.5-458.2]). It was unlikely to be the cause of fever at this low level. C-reactive protein (CRP) result was able to distinguish between dengue virus infection (9.0 milligrams per litre (mg/l) (Interquartile range [IQR] 7.9-18.0)) and bacterial infections (106.5 mg/l [IQR 40.8-166.5] for leptospirosis, 55.2 mg/l [IQR 40.7-114.0] for scrub typhus and 24.7 mg/l [IQR 15.0-48.6] for murine typhus, P<0.0001 for all). Conclusion The new generation ICT that included NS1 antigen detection was clinically useful and appropriate to implement in the field for early diagnosis of acute dengue infection. The rRT-PCR for dengue could replace the gold standard serology for early diagnosis using a single specimen. The IgM ICT, 47kDa and 17kDa qPCRs were inadequate for diagnosis of scrub typhus and murine typhus due to low clinical diagnostic sensitivity. For leptospirosis 16S rRNA qPCR, the excellent analytical performance warrants further investigation on its clinical usefulness. The CRP was found to be a useful tool to clinicians for determining whether a patient had a viral or bacterial infection. Early diagnosis of scrub typhus, murine typhus, and leptospirosis remains challenging. Development and clinical evaluation of improved diagnostic tests is urgently needed

Undocumented Burden of Dengue in Africa

In Africa, information on dengue burden in Africa is limited. Dengue diagnostics is also a key challenge in defining the true burden. Among the various diagnostic options, rapid diagnostic test (RDT) is a convenient and prompt tool for dengue diagnosis, especially in resource-limited environments. To assess current knowledge on the use of RDTs for dengue with respect to their economic impact, a systematic review was conducted of published data. Overall, data were limited to demonstrate an economic impact of dengue RDTs and the available two studies reached different conclusions: one concluded that one particular RDT would be a cost-effective tool in endemic setting, and the other, based on a modeling, showed that a dengue RDT would not be advantageous in terms of cost and effectiveness compared to current practice of antibiotics prescription for undifferentiated fever. This thesis presents patterns of dengue epidemiology and outbreak based on passive fever surveillance studies in Mombasa, Kenya, and Ouagadougou, Burkina Faso. To estimate the proportion and understand clinical patterns of dengue-positive cases among non-malarial febrile patients, we conducted passive health facility-based fever surveillance studies in Ouagadougou, Burkina Faso and Mombasa, Kenya. In Mombasa, of 482 non-malarial febrile patients, 223 (46%) were identified as dengue– confirmed and 92 (19%) as dengue-probable. The surveillance covered the beginning of a dengue outbreak in April-May 2017, during which 67% of enrolled patients were dengue-confirmed. In Ouagadougou, of 2929 non-malarial febrile patients, 540 (18%) were identified as dengue–confirmed and 571 (19%) as dengue-probable. During the study period, a dengue outbreak occurred in September-November 2016, during which 46% of enrolled patients were dengue-confirmed. To understand DENV transmission in the community, 4 repeated serosurveys were conducted among the same individuals at 6 month intervals in Ouagadougou. Seroprevalence at enrollment was 66%. The binomial regression based on IgG positivity by age, assuming constant force of infection (FoI) over calendar time, resulted in the FOI of 6% per year. In summary, in both Burkina Faso and Kenya, there is considerable transmission of DENV, in terms of proportion of DENV confirmed infections among iii non-malarial febrile patients in the healthcare facilities as well as seroprevalence and FoI in the community. These burden estimates can facilitate evidence-based decision making on interventions for dengue prevention and control, including a dengue vaccine. However, given the currently available information on dengue burden in Africa and the status of dengue vaccine development, including the only licensed vaccine with restrictions in public health use, consideration of dengue vaccine introduction may be premature for Africa and more data would be necessary to build evidence base on dengue in African settings

Ultrasensitive detection of toxocara canis excretory-secretory antigens by a nanobody electrochemical magnetosensor assay.

peer reviewedHuman Toxocariasis (HT) is a zoonotic disease caused by the migration of the larval stage of the roundworm Toxocara canis in the human host. Despite of being the most cosmopolitan helminthiasis worldwide, its diagnosis is elusive. Currently, the detection of specific immunoglobulins IgG against the Toxocara Excretory-Secretory Antigens (TES), combined with clinical and epidemiological criteria is the only strategy to diagnose HT. Cross-reactivity with other parasites and the inability to distinguish between past and active infections are the main limitations of this approach. Here, we present a sensitive and specific novel strategy to detect and quantify TES, aiming to identify active cases of HT. High specificity is achieved by making use of nanobodies (Nbs), recombinant single variable domain antibodies obtained from camelids, that due to their small molecular size (15kDa) can recognize hidden epitopes not accessible to conventional antibodies. High sensitivity is attained by the design of an electrochemical magnetosensor with an amperometric readout with all components of the assay mixed in one single step. Through this strategy, 10-fold higher sensitivity than a conventional sandwich ELISA was achieved. The assay reached a limit of detection of 2 and15 pg/ml in PBST20 0.05% or serum, spiked with TES, respectively. These limits of detection are sufficient to detect clinically relevant toxocaral infections. Furthermore, our nanobodies showed no cross-reactivity with antigens from Ascaris lumbricoides or Ascaris suum. This is to our knowledge, the most sensitive method to detect and quantify TES so far, and has great potential to significantly improve diagnosis of HT. Moreover, the characteristics of our electrochemical assay are promising for the development of point of care diagnostic systems using nanobodies as a versatile and innovative alternative to antibodies. The next step will be the validation of the assay in clinical and epidemiological contexts