The usefulness of serum C-reactive protein and total bilirubin levels for distinguishing between dengue fever and malaria in returned travelers

Biomarkers of disease severity in vivax malaria

Severe complications have been observed and established for Plasmodium falciparum as well as P. vivax infections worldwide. Although P. vivax infection is not fully acknowledged as malignant malaria, recently life-threatening complications have been reported to occur in many studies. The recognition of biomarkers with excellent sensitivity and reliability plays a prime role in disease management. Acute inflammatory response and oxidative stress are observed in malaria due to the production of reactive oxygen species. Lipid and protein oxidative injuries are prospective biomarkers for disease severity owing to the damage caused by the parasite. We have tried to find out whether protein carbonylation (PC), lipid peroxidation (LPO) and superoxide dismutase (SOD) could suffice as a biomarker for severe vivax malaria or not. Blood samples were collected from the individuals attending Jawaharlal Nehru Medical College of Aligarh Muslim University during the wet season of malaria transmission. Microscopy and rapid diagnostic kits were used as a tool for malaria diagnosis. A total of 214 subjects were enrolled for the study: 30 febrile controls and 184 subjects with vivax malaria. Protein carbonylation and lipid peroxidation were found to be directly associated with parasite count and total antioxidant status (TAS). Increase in oxidative stress was also observed in severe vivax malaria patients. Levels of uric acid and bilirubin too were raised in complicated cases. Protein carbonylation was found to be a more reliable indicator of vivax malaria severity than lipid peroxidation.

C-reactive protein as a potential biomarker for disease progression in dengue: a multi-country observational study

BACKGROUND

Dengue infection can cause a wide spectrum of clinical outcomes. The severe clinical manifestations occur sufficiently late in the disease course, during day 4-6 of illness, to allow a window of opportunity for risk stratification. Markers of inflammation may be useful biomarkers. We investigated the value of C-reactive protein (CRP) measured early on illness days 1-3 to predict dengue disease outcome and the difference in CRP levels between dengue and other febrile illnesses (OFI).

METHOD

We performed a nested case-control study using the clinical data and samples collected from the IDAMS-consortium multi-country study. This was a prospective multi-center observational study that enrolled almost 8000 participants presenting with a dengue-like illness to outpatient facilities in 8 countries across Asia and Latin America. Predefined severity definitions of severe and intermediate dengue were used as the primary outcomes. A total of 281 cases with severe/intermediate dengue were compared to 836 uncomplicated dengue patients as controls (ratio 1:3), and also 394 patients with OFI.

RESULTS

In patients with confirmed dengue, median (interquartile range) of CRP level within the first 3 days was 30.2 mg/L (12.4-61.2 mg/L) (uncomplicated dengue, 28.6 (10.5-58.9); severe or intermediate dengue, 34.0 (17.4-71.8)). Higher CRP levels in the first 3 days of illness were associated with a higher risk of severe or intermediate outcome (OR 1.17, 95% CI 1.07-1.29), especially in children. Higher CRP levels, exceeding 30 mg/L, also associated with hospitalization (OR 1.37, 95% CI 1.14-1.64) and longer fever clearance time (HR 0.84, 95% CI 0.76-0.93), especially in adults. CRP levels in patients with dengue were higher than patients with potential viral infection but lower than patients with potential bacterial infection, resulting in a quadratic association between dengue diagnosis and CRP, with levels of approximately 30 mg/L associated with the highest risk of having dengue. CRP had a positive correlation with total white cell count and neutrophils and negative correlation with lymphocytes, but did not correlate with liver transaminases, albumin, or platelet nadir.

CONCLUSIONS

In summary, CRP measured in the first 3 days of illness could be a useful biomarker for early dengue risk prediction and may assist differentiating dengue from other febrile illnesses.

Acute phase protein response to viral infection and vaccination

Organisms respond in multiple ways to microbial infections. Pathogen invasion tipically triggers an inflammatory response where acute phase proteins (APP) have a key role. Pentraxins (PTX) are a family of highly conserved APP that play a part in the host defense against infection. The larger proteins of the family are simply named pentraxins, while c-reactive proteins (CRP) and serum amyloid proteins (SAA, SAP) are known as short pentraxins. Although high APP levels have been broadly associated with bacterial infections, there is a growing body of evidence revealing increased PTX, CRP and SAP expression upon viral infection. Furthermore, CRP, PTX and SAP have shown their potential as diagnostic markers and predictors of disease outcome. Likewise, the measurement of APP levels can be valuable to determine the efficacy of antiviral therapies and vaccines. From the practical point of view, the ability of APP to reduce viral infectivity has been observed in several virus-host models. This has prompted investigation efforts to assess the role of acute phase response proteins as immunoregulatory molecules and their potential as therapeutic reagents. This work aims to present an overview of the APP response to viral infections reviewing the current knowledge in the field.

Differential status and significance of non-enzymatic antioxidants (reactive oxygen species scavengers) in malaria and dengue patients

An imbalance in oxidants and antioxidants is observed during malaria and dengue infections which is associated with the production of reactive oxygen species (ROS) via haem degradation or immune activation, a contributing factor for disease pathogenesis. The levels of non-enzymatic antioxidants and total antioxidant status (TAS) in malaria and dengue patients were analysed and compared with healthy controls. Particular attention was paid to elevated levels of total bilirubin (TB) and uric acid (UA) during disease progression and haemolysis and noticed a significant increase in dengue patients (dengue>Pf>Pv>control). A highly significant difference was also observed between dengue and Pf patients (p < 0.0001) for these parameters. Glutathione levels were comparable in dengue and falciparum malaria but were significantly higher than that of vivax malaria patients. Ascorbate levels were significantly depleted in all the patient groups (p < 0.0001) and a negative correlation was established for TAS and ascorbate levels in dengue patients (r=-0.32). A good positive correlation was observed between TAS-UA and TAS-TB levels. Thus, these findings suggest that severe haemolysis, renal failure, and liver dysfunction have higher prominence in dengue patients during the simultaneous outbreak of the two arthropod-borne diseases. A differential status of non-enzymatic antioxidants was also observed during the different stages of dengue and malaria.

Serum Bilirubin and Their Association With C-Reactive Protein in Patients With Migraine

BACKGROUND

Increased levels of C-reactive protein (CRP) have been considered as a marker in assessing neurogenic inflammation of migraine patients. An inverse relationship between serum bilirubin and CRP has been observed in various diseases. Therefore, we analyzed serum bilirubin levels in migraine patients, and investigated the relationship between serum bilirubin and CRP in migraineurs.

METHODS

A total of 86 newly diagnosed migraine patients were consecutively recruited to this study.

RESULTS

Significantly lower median serum total bilirubin, conjugated bilirubin (CB) and unconjugated bilirubin were found in patients with migraine than healthy controls, and the levels of CRP were significantly higher in migraine patients than healthy controls. A negative correlation between CRP and CB was observed in patients with migraine (r = -0.255, P = 0.018). In a multiple linear regression model, the concentrations of CRP remained negatively correlated with CB.

CONCLUSIONS

Our study demonstrates that serum bilirubin concentrations are decreased in migraineurs, and CB levels were found to be positively correlated with CRP in migraine patents. However, larger cross-sectional and prospective studies are needed to establish whether serum bilirubin may be a useful biomarker for assessing neurogenic inflammation in migraine patients and eventually guiding the therapy.

Unravelling the patterns of host immune responses in Plasmodium vivax malaria and dengue co-infection

BACKGROUND

Concurrent malaria and dengue infection is frequently diagnosed in endemic countries, but its immunopathology remains largely unknown. In the present study, a large panel of cytokines/chemokines and clinical laboratory markers were measured in patients with Plasmodium vivax and dengue co-infection as well as in individuals with malaria or dengue mono-infections in order to identify biosignatures of each clinical condition.

METHODS

Individuals from the Brazilian Amazon were recruited between 2009 and 2013 and classified in three groups: vivax malaria (n = 52), dengue (n = 30) and vivax malaria and dengue co-infection (n = 30). P. vivax malaria was diagnosed by thick blood smear and confirmed by PCR; dengue cases were detected by IgM ELISA or NS1 protein. The plasma levels of cytokines and chemokines were determined by multiplex assay.

RESULTS

Individuals with malaria and dengue co-infection displayed lower levels of platelets and haemoglobin than those with malaria or dengue mono-infections (p = 0.0047 and p = 0.0001, respectively). The group of individuals co-infected exhibited the highest median concentrations of IFN-γ, IL-6, CCL4 than the mono-infected groups. Network analyses of plasma cytokines/chemokines revealed that malaria and dengue co-infection exhibits a distinct immune profile with critical roles for TNF, IL-6 and IFN-γ. Further, parasitaemia levels displayed positive significant interactions with IL-6, CCL4 and IL-10 in the group of patients co-infected with malaria and dengue. No differences were observed in distribution of dengue virus serotypes and Plasmodium parasitaemia levels between the groups.

CONCLUSIONS

The findings described here identify unique patterns of circulating immunological markers in cases of malaria and dengue co-infection and provide insights on the immunopathology of this co-morbid condition.

Comparison of clinical characteristics and laboratory findings of malaria, dengue, and enteric fever in returning travelers: 8-year experience at a referral center in Tokyo, Japan

BACKGROUND

Without specific symptoms, diagnosis of febrile illness in returning travelers is challenging. Dengue, malaria, and enteric fever are common causes of fever in returning travelers and timely and appropriate treatment is important. However, differentiation is difficult without specific diagnostic tests.

METHODS

A retrospective study was conducted at the National Centre for Global Health and Medicine (NCGM) from April 2005 to March 2013. Febrile travelers returning from overseas who were diagnosed with dengue, malaria, or enteric fever were included in this study. Clinical characteristics and laboratory findings were compared for each diagnosis.

RESULTS

During the study period, 86 malaria, 85 dengue, and 31 enteric fever cases were identified. The mean age of the study cohort was 33.1 ± 12 years and 134 (66.3%) study participants were male. Asia was the most common area visited by returning travelers with fevers (89% of dengue, 18.6% of malaria, and 100% of enteric fever cases), followed by Africa (1.2% of dengue and 70.9% of malaria cases). Clinical characteristics and laboratory findings were significantly different among each group with each diagnosis. Decision tree models revealed that returning from Africa and CRP levels <10 mg/L were factors specific for diagnosis of malaria and dengue fever, respectively.

CONCLUSION

Clinical manifestations, simple laboratory test results, and regions of travel are helpful to distinguish between dengue, malaria, and enteric fever in febrile returning travelers with non-specific symptoms.

Travel-related leptospirosis in Japan: a report on a series of five imported cases diagnosed at the National Center for Global Health and Medicine

Leptospirosis is one of the most common travel-related infections. We report 5 cases of travel-related leptospirosis who presented at our clinic between January 2008 and December 2013. Patients were included in the study if they presented with a clinical profile that was compatible with the disease within 21 days of their return from traveling, which were laboratory-diagnosed as leptospirosis by blood culture, rise in antibody titers in paired sera using the microscopic agglutination test (MAT), and/or DNA detection using flaB-nested PCR. Five leptospirosis cases were evaluated, all of which contracted the disease after exposure to fresh water in Southeast Asian countries. All of the cases had fevers, headaches, conjunctival injections, and relative bradycardia. The pertinent laboratory findings included elevated C-reactive protein levels, elevated creatinine levels, and sterile pyuria. All 5 cases had serum MAT titers that increased by ≥ 4 times in the interval between specimens taken during the acute phase and those taken during the convalescence phase, and leptospiral DNA was detected in plasma and/or urine specimens in 4 cases. Leptospira interrogans was isolated from one patient's blood sample. Patients were treated with penicillin G, minocycline, or doxycycline. One case was cured without antibiotics. A diagnosis of leptospirosis should be considered for febrile travelers who return from Southeast Asian countries to Japan after being exposed to freshwater while traveling.