Laboratory indicators of the diagnosis and course of imported malaria

Epidemiological and clinical characteristics of imported falciparum malaria in the Republic of North Macedonia : A 13-year experience

BACKGROUND

Plasmodium falciparum is the leading cause of imported malaria and the most common cause of death in returning travellers.

AIM

To identify the main epidemiological and clinical characteristics of patients with imported falciparum malaria in the Republic of North Macedonia.

MATERIAL AND METHODS

Retrospectively analyzed were the epidemiological and clinical features of 34 patients with imported falciparum malaria who were diagnosed and treated at the university clinic for infectious diseases and febrile conditions in Skopje from 2010 to 2022. Malaria diagnosis was based on the microscopic detection of parasites in thick and thin blood smears.

RESULTS

All patients were male, with a median age of 36 years and a range of 22-60 years. Of the patients 33 (97.1%) acquired the disease in Sub-Saharan Africa. All patients except one stayed in endemic regions for work/business purposes. Chemoprophylaxis was completely applied in 4 (11.8%) patients. The median time of onset between the symptoms and diagnosis was 4 days, with a range of 1-12 days. Prevailing clinical manifestations were fever, chills, and splenomegaly in 100%, 94%, and 68% of patients, respectively. Severe malaria was noticed in 8 (23.5%) patients. In 5 (14.7%) patients the initial parasitemia was higher than 5%. On admission, thrombocytopenia, hyperbilirubinemia, and elevated alanine aminotransferase were registered in 94%, 58%, and 62% of patients, respectively. Out of the 33 patients with adequate follow-up, the outcome was favorable in 31 (93.9%).

CONCLUSION

In every febrile traveller returned from Africa, imported falciparum malaria should be an essential part of differential diagnostic considerations.

C-reactive protein as an early biomarker for malaria infection and monitoring of malaria severity: a meta-analysis

This study investigated whether C-reactive protein (CRP) can be used as a marker for the early detection and monitoring of malaria severity. Potentially relevant studies were searched in Medline (PubMed), Scopus, and Web of Science. Differences in CRP between (1) severe malaria and uncomplicated malaria, (2) uncomplicated malaria and asymptomatic malaria, (3) uncomplicated malaria and febrile/healthy controls, and (4) asymptomatic malaria and febrile/healthy controls were estimated using random-effects models. Twenty-nine studies were included for meta-analysis. The results of meta-analysis demonstrated higher mean CRP levels in (1) patients with severe malaria compared with uncomplicated malaria (p < 0.001, standard mean difference [SMD]: 1.52, 95% confidence interval [CI]: 0.91-2.12, I2: 95.1%), (2) patients with uncomplicated malaria than in those with asymptomatic malaria (p: 0.001, SMD: 1.65, 95% CI: 0.67-2.62, I2: 96.7%), (3) patients with uncomplicated malaria compared with febrile/healthy controls (p < 0.001, SMD: 2.38, 95% CI: 1.37-3.40, I2: 98.5%), and (4) patients with asymptomatic malaria compared with febrile/healthy controls (p < 0.001, SMD: 2.55, 95% CI: 1.60-3.50, I2: 99.2%). This study demonstrated CRP levels are a biomarker for the early detection and monitoring of malaria severity.

Imported malaria in a non-endemic area: the experience of the university of Campinas hospital in the Brazilian Southeast

BACKGROUND

Although malaria in Brazil almost exclusively occurs within the boundaries of the Amazon Region, some concerns are raised regarding imported malaria to non-endemic areas of the country, notably increased incidence of complications due to delayed diagnoses. However, although imported malaria in Brazil represents a major health problem, only a few studies have addressed this subject.

METHODS

A retrospective case series is presented in which 263 medical charts were analysed to investigate the clinical and epidemiological characterization of malaria cases that were diagnosed and treated at Hospital & Clinics, State University of Campinas between 1998 and 2011.

RESULTS

Amongst all medical charts analysed, 224 patients had a parasitological confirmed diagnosis of malaria. Plasmodium vivax and Plasmodium falciparum were responsible for 67% and 30% of the infections, respectively. The majority of patients were male (83%) of a productive age (median, 37 years old). Importantly, severe complications did not differ significantly between P. vivax (14 cases, 9%) and P. falciparum (7 cases, 10%) infections.

CONCLUSIONS

Severe malaria cases were frequent among imported cases in Brazil outside of the Amazon area. The findings reinforce the idea that P. vivax infections in Brazil are not benign, regardless the endemicity of the area studied. Moreover, as the hospital is located in a privileged site, it could be used for future studies of malaria relapses and primaquine resistance mechanisms. Finally, based on the volume of cases treated and the secondary complications, referral malaria services are needed in the non-endemic areas of Brazil for a rapid and efficient and treatment.

Laboratory features of common causes of fever in returned travelers

BACKGROUND

There can be considerable overlap in the clinical presentation and laboratory features of dengue, malaria, and enteric fever, three important causes of fever in returned travelers. Routine laboratory tests including full blood examination (FBE), liver function tests (LFTs), and C-reactive protein (CRP) are frequently ordered on febrile patients, and may help differentiate between these possible diagnoses.

METHODS

Adult travelers returning to Australia who presented to the Royal Melbourne Hospital with confirmed diagnosis of dengue, malaria, or enteric fever between January 1, 2000 and March 1, 2013 were included in this retrospective study. Laboratory results for routine initial investigations performed within the first 2 days were extracted and analyzed.

RESULTS

There were 304 presentations including 58 with dengue fever, 187 with malaria, and 59 with enteric fever, comprising 56% of all returned travelers with a febrile systemic illness during the study period. Significant findings included 9-fold and 21-fold odds of a normal CRP in dengue compared with malaria and enteric fever, respectively. The odds of an abnormally low white cell count (WCC) were also significantly greater in dengue versus malaria or enteric fever. Approximately one third of dengue presentations and almost half of the malaria presentations had platelet counts <100 × 10(9) /L. A normal CRP with leukopenia and/or thrombocytopenia occurred in 21% to 30% of dengue presentations, but not in malaria or enteric fever presentations.

CONCLUSIONS

There is a wide differential diagnosis for imported fever, but the non-specific findings of a normal CRP with a low WCC and/or low platelet count may provide useful information in addition to clinical clues to suggest dengue over malaria or enteric fever. Further systematic prospective studies among travelers could help define the potential clinical utility of these results in assisting the clinician when deciding for or against commencement of empiric antimicrobial therapy while awaiting confirmatory tests.

C-reactive protein and the biology of disease

The C-reactive protein (CRP) is a plasma protein of hepatic origin, belonging to pentraxin family and forms a major component of any inflammatory reaction. A key component of the innate immunity pathway, the concentration of CRP may rapidly increase to levels more than 1,000-folds above normal values as a consequence to tissue injury or infection. Although functioning as a classical mediator of innate immunity, it functions via interaction of components of both humoral and cellular effector systems of inflammation. Initially considered as an acute-phase marker in tissue injury, infection and inflammation, it now has a distinct status of a disease marker in cardiovascular diseases and is well known of its clinical and pathological significance. The present torrent of studies in a large number of diseases and associated conditions has highly elucidated the role of CRP as a therapeutic and research reagent. In this review, we focus our attention to role of CRP in health and disease. The future prospect of this review lies in the applicability of CRP as a molecule in understanding and monitoring of the biology of disease.

Cases of typhoid fever in Copenhagen region: a retrospective study of presentation and relapse

Background

Typhoid fever is a systemic illness which in high-income countries mainly affects travellers. The incidence is particularly high on the Indian subcontinent. Travellers who visit friends and relatives (VFR) have been shown to have a different risk profile than others. We wished to identify main characteristics for travellers infected with S. Typhi considering both clinical and laboratory findings in order to provide for faster and better diagnostics in the future. The outcome of treatment, especially concerning relapse, was evaluated as well.

Methods

Retrospectively collected data from 19 adult cases of typhoid fever over a 5-year period at the Department of Infectious Diseases, Copenhagen University Hospital, Hvidovre Denmark.

Results

The patients were young adults, presenting with symptoms within a month after travelling. 84% were returned from travelling in the Indian subcontinent. 17 out of 19 patients were VFR-travellers. The main symptoms were fever (100%), gastrointestinal symptoms (84%), headache (58%) and dry cough (26%). Laboratory findings showed elevated C-reactive protein (CRP) and lactate dehydrogenase (LDH) in all cases and elevated alanine transaminase (ALAT) in 47% of cases. In primary cases 4 isolates were fully susceptible to ciprofloxacin, the remaining were intermediate susceptible. Relapse occurred in 37% of the cases and only in cases where the patient was infected by a strain with intermediate susceptibility.

Conclusions

Better pre-travel counselling should be given to VFR-travellers. The main symptoms and laboratory findings confirm previous findings. The relapse rate was unexpected high and could be correlated to ciprofloxacin-resistance.

Bacterial coinfections in travelers with malaria: rationale for antibiotic therapy

Malaria predisposes children in areas where malaria is endemic to concurrent bacteremia, often with severe outcomes. The importance of bacterial coinfections in patients diagnosed with malaria in nonendemic settings has, however, not been reported. A retrospective analysis of microbiology data was performed in 755 travelers diagnosed with malaria in Sweden. Bacterial cultures from blood and other locations were correlated to clinical outcome and antibiotic treatment. Blood cultures were drawn from 417 (55%) patients (88% of whom were >15 years old), and bacterial isolates of clinical relevance (Salmonella enterica serovar Enteritidis and Escherichia coli) were detected in 2 patients (0.3%). Cultures from other locations (mainly urine, nasopharyngeal, and fecal samples) were obtained from 44% of the patients with 4.9% positivity. Of the 38 patients given antibiotics, 47% had neither severe malaria nor positive cultures and/or radiology signs indicative of treatment. C-reactive protein levels were associated with bacterial infections but had only a fair predictive value. Bacterial coinfections are uncommon among travelers with malaria. These data suggest a weaker association between malaria and bacteremia than previously described in endemic settings and might indicate different patient populations with different pathophysiological mechanisms and microbial environments. The study supports a restrictive antibiotic policy in returning travelers with malaria.

Development and evaluation of a multiplex screening assay for Plasmodium falciparum exposure

Transfusion transmitted malaria (TTM) in non-endemic countries is reduced by questioning blood donors and screening of donated blood. Conventional screening is performed by Indirect Fluorescence Antibody Test (IFAT). This method is manual and difficult to standardize. Here we study the diagnostic performance of a multiplex assay for detection of antibodies against Plasmodium falciparum in donor blood using IFAT as a comparator. A multiplex assay (MPA) containing the antigens GLURP-R0, GLURP-R2, MSP3, MSP1 hybrid and AMA1 was constructed using xMAP® technology. A discrimination index for exposure to P. falciparum malaria was calculated by comparing travelers with clinical malaria (n=52) and non-exposed blood donors (n=119). The index was evaluated on blood donors with suspected malaria exposure (n=249) and compared to the diagnostic performance of IFAT. At a specificity of 95.8 %, the MPA discrimination index exhibited a diagnostic sensitivity of 90.4 % in travelers hospitalized with malaria. Percent agreement with IFAT was 92.3 %. Screening plasma from blood donors with suspected malaria exposure, we found 4.8 % to be positive by IFAT and 5.2 % by MPA with an agreement of 93.2 %. The calculated index from the MPA exhibits similar diagnostic performance as IFAT for detection of P. falciparum malaria. Combining the antibody response against multiple antigens in a discrimination index increased the sensitivity of the MPA and reduced the readout to a single value.

Imported malaria: an update

Evidence suggests that imported malaria is a diagnostic challenge with initial misdiagnosis rates of 40% or greater. Given that prompt diagnosis and appropriate treatment are the only intervention proven to prevent progression to severe malaria and death, these figures are concerning. The purpose of this clinical review is to provide the most up-to-date and practical information on the diagnosis and treatment of imported malaria for the emergency health care provider. We highlight common pitfalls, errors, and mistakes in arriving at the correct diagnosis. We also emphasize the 3 key aspects to avoid progression to severe disease: rapid diagnosis, prompt initiation of treatment, and appropriate choice of antimalarial treatment.

Fever in travelers returning from malaria-endemic areas: don't look for malaria only

BACKGROUND

Returning travelers with fever pose challenges for clinicians because of the multitude of diagnostic alternatives. Case data in a Finnish tertiary hospital were analyzed in order to define the causes of fever in returned travelers and to evaluate the current diagnostic approach.

METHODS

A retrospective study of patient records comprised 462 febrile adults who, after traveling in malaria-endemic areas, were admitted to the Helsinki University Central Hospital (HUCH) emergency room from 2005 to 2009. These patients were identified through requests for malaria smear.

RESULTS

The most common groups of diagnoses were acute diarrheal disease (126 patients/27%), systemic febrile illness (95/21%), and respiratory illness (69/15%). The most common specific main diagnosis was Campylobacter infection (40/9%). Malaria was diagnosed in 4% (20/462). Blood culture was positive for bacteria in 5% of those tested (21/428). Eight patients were diagnosed with influenza. HIV-antibodies were tested in 174 patients (38%) and proved positive in 3% of them (5/174, 1% of all patients). The cause of fever was noninfectious in 12 (3%), remaining unknown in 116 (25%). Potentially life-threatening illnesses were diagnosed in 118 patients (26%), the strongest risk factors were baseline C-reactive protein (CRP) ≥100 (OR 3.6; 95% CI 2.0-6.4) and platelet count ≤140 (OR 3.8; 95% CI 2.0-7.3). Nine patients (2%) were treated in high dependency or intensive care units; one died of septicemia. Forty-five patients (10%) had more than one diagnosis.

CONCLUSION

The high proportion of patients with more than one diagnosis proves the importance of careful diagnostics. Every fourth returning traveler with fever had a potentially life-threatening illness. Septicemia was as common as malaria. The proportion of HIV cases exceeded the prevalence in population for which Centers for Disease Control and Prevention, USA (CDC) recommends routine HIV testing. Both blood cultures and HIV tests should be considered in febrile travelers.

Predictive factors of imported malaria in 272 febrile returning travelers seen as outpatients

BACKGROUND

We conducted a prospective study to evaluate the aetiologies of fever in returning travelers and to identify the clinical and laboratory factors predictive of malaria in travelers returning from tropical areas with fever.

METHODS

We included those consulting for fever appearing less than 3 months after return. Destinations were classified according to the visited continent (America including Caribbean, Asia, Africa, Oceania). We prospectively included all returning travelers consulting our department between November 2002 and May 2003 for health problems and investigated those presenting fever within 3 months after return from a tropical country. We then conducted a case control study to identify factors predictive of malaria. Control group was defined as febrile travelers without malaria.

RESULTS

A total of 272 febrile travelers were included. They were 152 tourists (55.9%), 58 immigrants (21.3%), 33 expatriates (12.1%), and 29 business travelers (10.7%). Besides malaria (54 cases), the main diagnosis in the 218 controls were bacterial enteritis, bacterial pneumonia, infectious cellulitis, pyelonephritis, prostatis, dengue fever, primary viral infection (HIV, EBV, CMV, parvovirus B19), and tuberculosis. Multivariate regression analysis showed correlations between malaria and travel to Africa (OR = 11.9), abdominal pain (OR = 14.1), vomiting (OR = 19.4), myalgia (OR = 6.3), inadequate prophylaxis (OR = 10.1), and platelets <150,000/microL (OR = 25.2).

CONCLUSIONS

Our results suggest that no single clinical or biological feature had both good sensitivity and specificity to predict malaria in febrile travelers seen as outpatients within 3 months after returning from the tropics.