Viral hemorrhagic fever in the tropics: Report from the task force on tropical diseases by the World Federation of Societies of Intensive and Critical Care Medicine

Administration of airborne pathogens in non-human primates

PURPOSE

Airborne pathogen scan penetrate in human respiratory tract and can cause illness. The use of animal models to predict aerosol deposition and study respiratory disease pathophysiology is therefore important for research and a prerequisite to test and study the mechanism of action of treatment. NHPs are relevant animal species for inhalation studies because of their similarities with humans in terms of anatomical structure, respiratory parameters and immune system.

MATERIALS AND METHODS

The aim of this review is to provide an overview of the state of the art of pathogen aerosol studies performed in non-human primates (NHPs). Herein, we present and discuss the deposition of aerosolized bacteria and viruses. In this review, we present important advantages of using NHPs as model for inhalation studies.

RESULTS

We demonstrate that deposition in the respiratory tract is not only a function of aerosol size but also the technique of administration influences the biological activity and site of aerosol deposition. Finally, we observe an influence of a region of pathogen deposition in the respiratory tract on the development of the pathophysiological effect in NHPs.

CONCLUSION

The wide range of methods used for the delivery of pathogento NHP respiratory airways is associated with varying doses and deposition profiles in the airways.

Predictive epidemiological, clinical and laboratory parameters in the diagnosis of Crimean-Congo hemorrhagic fever

Background: The aim of this study is to determine predictive parameters that can be used in the differential diagnosis of Crimean-Congo Hemorrhagic Fever (CCHF) and other diseases with similar clinical and laboratory findings. Materials & methods: In this study, epidemiological, clinical and laboratory parameters of 107 CCHF-positive and 71 CCHF-negative patients were compared. Results: Alanine amino transferase, aspartate aminotransferase, creatine kinase, lactate dehydrogenase, red blood cell, hemoglobin and hematocrit were significantly higher in CCHF-positive patients, whereas total and direct bilirubin, alkaline phosphatase, prothrombin time, international normalization ratio, white blood cell, C-reactive protein and procalcitonin were higher in CCHF-negative patients. In binary logistic regression analysis, an increase in activated partial thromboplastin time level was identified as an independent predictor of having CCHF, while alanine amino transferase, white blood cell and C-reactive protein elevations were identified as independent predictors of not having CCHF. Conclusion: In endemic areas where PCR and serological tests are delayed, knowing the predictive parameters may be of vital importance in the early diagnosis of CCHF.

The Emergence of Travel-related Infections in Critical Care Units

Several tropical or geographically confined infectious diseases may lead to organ failure requiring management in an intensive care unit (ICU), both in endemic low- and middle-income countries where ICU facilities are increasingly being developed and in (nonendemic) high-income countries through an increase in international travel and migration. The ICU physician must know which of these diseases may be encountered and how to recognize, differentiate, and treat them. The four historically most prevalent "tropical" diseases (malaria, enteric fever, dengue, and rickettsiosis) can present with single or multiple organ failure in a very similar manner, which makes differentiation based solely on clinical signs very difficult. Specific but frequently subtle symptoms should be considered and related to the travel history of the patient, the geographic distribution of these diseases, and the incubation period. In the future, ICU physicians may also be more frequently confronted with rare but frequently lethal diseases, such as Ebola and other viral hemorrhagic fevers, leptospirosis, and yellow fever. No one could have foreseen the worldwide 2019-up to now coronavirus disease 2019 (COVID-19) crisis caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which was initially spread by travel too. In addition, the actual pandemic due to SARS-CoV-2 reminds us of the actual and potential threat of (re)-emerging pathogens. If left untreated or when treated with a delay, many travel-related diseases remain an important cause of morbidity and even mortality, even when high-quality critical care is provided. Awareness and a high index of suspicion of these diseases is a key skill for the ICU physicians of today and tomorrow to develop.

Coagulopathy of Dengue and COVID-19: Clinical Considerations

Thrombocytopenia and platelet dysfunction commonly occur in both dengue and COVID-19 and are related to clinical outcomes. Coagulation and fibrinolytic pathways are activated during an acute dengue infection, and endothelial dysfunction is observed in severe dengue. On the other hand, COVID-19 is characterised by a high prevalence of thrombotic complications, where bleeding is rare and occurs only in advanced stages of critical illness; here thrombin is the central mediator that activates endothelial cells, and elicits a pro-inflammatory reaction followed by platelet aggregation. Serological cross-reactivity may occur between COVID-19 and dengue infection. An important management aspect of COVID-19-induced immunothrombosis associated with thrombocytopenia is anticoagulation with or without aspirin. In contrast, the use of aspirin, nonsteroidal anti-inflammatory drugs and anticoagulants is contraindicated in dengue. Mild to moderate dengue infections are treated with supportive therapy and paracetamol for fever. Severe infection such as dengue haemorrhagic fever and dengue shock syndrome often require escalation to higher levels of support in a critical care facility. The role of therapeutic platelet transfusion is equivocal and should not be routinely used in patients with dengue with thrombocytopaenia and mild bleeding. The use of prophylactic platelet transfusion in dengue fever has strained financial and healthcare systems in endemic areas, together with risks of transfusion-transmitted infections in low- and middle-income countries. There is a clear research gap in the management of dengue with significant bleeding.

Human Alkhumra hemorrhagic Fever: Emergence, history and epidemiological and clinical profiles

Alkhumra hemorrhagic fever (AHF) is a severe, often fatal hemorrhagic disease in humans. It is caused by Alkhumra hemorrhagic fever virus (AHFV), a newly described flavivirus first isolated in 1995 in Alkhumra district, south of Jeddah City, Saudi Arabia. It is transmitted from infected livestock animals to humans by direct contact with infected animals or by tick bites. In the recent past, the incidence of AHF has increased, with a total of 604 confirmed cases have been reported in Saudi Arabia between 1995 and 2020. Yet, no specific treatment or control strategies have been developed and implemented against this infection. Hence, the likelihood of increased prevalence or the occurrence of outbreaks is high, particularly in the absence of appropriate prevention and control strategies. This narrative review presents an overview of the current knowledge and future concerns about AHF globally.

Comparison and Evaluation of Real-Time Taqman PCR for Detection and Quantification of Ebolavirus

Given that ebolavirus causes severe and frequently lethal disease, its rapid and accurate detection using available and validated methods is essential for controlling infection. Real-time reverse-transcription PCR (RT-PCR) has proven to be an invaluable tool for ebolaviruses diagnostics. Many assays with different targets have been developed, but they have not been externally compared or validated, and limits of detection are not uniformly reported. Here we compared and evaluated the sensitivity, reproducibility and specificity of 23 in-house assays under the same conditions. Our results showed that these assays were highly gene- and species- specific when evaluated using in vitro RNA transcripts and viral RNA, and the potential limits of detection were uniformly reported ranging from 102 to 106 in vitro synthesized RNA transcripts copies perμL and 1-100 TCID50/mL. The comparison of these assays indicated that those targeting the more conservative NP gene could be the better option for EVD case definition and quantitative measurement because of its higher sensitivity for the same species. Our analysis could contribute to the standardization of ebolavirus detection and quantification assays, which can offer a better understanding of the meaning of results across laboratories and time points, as well as make them easy to implement, especially under outbreak conditions.

Viral-induced inflammatory coagulation disorders: Preparing for another epidemic

A number of viral infectious diseases have emerged or reemerged from wildlife vectors that have generated serious threats to global health. Increased international traveling and commerce increase the risk of transmission of viral or other infectious diseases. In addition, recent climate changes accelerate the potential spread of domestic disease. The Coronavirus disease 2019 (COVID-19) pandemic is an important example of the worldwide spread, and the current epidemic will unlikely be the last. Viral hemorrhagic fevers, such as Dengue and Lassa fevers, may also have the potential to spread worldwide with a significant impact on public health with unpredictable timing. Based on the important lessons learned from COVID-19, it would be prudent to prepare for future pandemics of life-threatening viral diseases. Among the various threats, this review focuses on the coagulopathy of acute viral infections since hypercoagulability has been a major challenge in COVID-19, but represents a different presentation compared to viral hemorrhagic fever. However, both thrombosis and hemorrhage are understood as the result of thromboinflammation due to viral infections, and the role of anticoagulation is important to consider.

Knowledge, attitudes and practices of healthcare workers within an Australian tertiary hospital to managing high-consequence infectious diseases

BACKGROUND

Adequate preparation and support for healthcare workers (HCWs) managing high-consequence infectious diseases (HCIDs) is critical to the overall clinical management of HCIDs. Qualitative studies examining how well prepared and supported HCWs feel are lacking despite their key role. This study investigated how prepared and supported front-line HCWs at an Australian tertiary hospital felt about managing HCIDs such as viral haemorrhagic fever (VHF).

METHODS

A qualitative research approach was used to undertake interviews with 45 Royal Melbourne Hospital medical and nursing staff from emergency, intensive care and infectious diseases. Interview questions captured data on HCWs' role, familiarity with using protocols, psychological attributes and training for scenarios related to VHF patient management. Interviews were recorded and transcribed. Categorical responses were analysed quantitatively and open-ended responses were analysed thematically.

RESULTS

Ninety-eight percent of participants indicated feeling capable of undertaking their role in managing VHF patients; 77% felt supported through personnel/resources. However, 69% indicated barriers to managing these patients effectively; and 68% felt anxious at the prospect of managing VHF patients. Themes emerging from participants' observations included concerns about training frequency, miscommunication, difficulty with uncertainty, feeling underprepared, and fear of transmitting infection to others.

CONCLUSION

Although the majority of HCWs feel confident about their ability to care for VHF patients, they also have a moderately-high degree of anxiety. Perceptions of interviewed staff have fed into recommendations to increase HCW preparedness and reduce anxiety, which include investigating support services, and exploring training options that create multi-departmental groups of highly specialised medical officers and nurses.

Update in Viral Infections in the Intensive Care Unit

The advent of highly sensitive molecular diagnostic techniques has improved our ability to detect viral pathogens leading to severe and often fatal infections that require admission to the Intensive Care Unit (ICU). Viral infections in the ICU have pleomorphic clinical presentations including pneumonia, acute respiratory distress syndrome, respiratory failure, central or peripheral nervous system manifestations, and viral-induced shock. Besides de novo infections, certain viruses fall into latency and can be reactivated in both immunosuppressed and immunocompetent critically ill patients. Depending on the viral strain, transmission occurs either directly through contact with infectious materials and large droplets, or indirectly through suspended air particles (airborne transmission of droplet nuclei). Many viruses can efficiently spread within hospital environment leading to in-hospital outbreaks, sometimes with high rates of mortality and morbidity, thus infection control measures are of paramount importance. Despite the advances in detecting viral pathogens, limited progress has been made in antiviral treatments, contributing to unexpectedly high rates of unfavorable outcomes. Herein, we review the most updated data on epidemiology, common clinical features, diagnosis, pathogenesis, treatment and prevention of severe community- and hospital-acquired viral infections in the ICU settings.

The electrochemical detection of bioterrorism agents: a review of the detection, diagnostics, and implementation of sensors in biosafety programs for Class A bioweapons

During the past year, disease has shown us the iron grip it can hold over a population of people. Health systems can be overwhelmed, economies can be brought into recession, and many people can be harmed or killed. When weaponized, diseases can be manipulated to create a detriment to health while becoming an economic burden on any society. It is consequently prudent that easy detection of bioweapons is available to governments for protecting their people. Electrochemical sensing displays many distinct advantages, such as its low limit of detection, low cost to run, rapid generation of results, and in many instances portability. We therefore present a wide array of electrochemical sensing platforms currently being fabricated, a brief summary of Class A bioweapons, and the potential future of bioweapon detection and biosafety.

Dengue and Other Viral Hemorrhagic Fevers

How to cite this article: Shastri PS, Taneja S. Dengue and Other Viral Hemorrhagic Fevers. Indian J Crit Care Med 2021;25(Suppl 2):S130–S133.

Conduite à tenir devant un enfant fébrile au retour de voyage☆

Les pathologies le plus fréquentes au retour de voyage à l’étranger sont les infections gastro-intestinales, les maladies fébriles et les problèmes dermatologiques. L’évaluation d’un enfant fébrile de retour de voyage est clinique : vérification des antécédents et des vaccinations, recherche d’autres cas au contact, signes fonctionnels et physiques, caractéristiques du voyage. Un bilan paraclinique de débrouillage complète souvent l’évaluation pour une orientation syndromique. Si les causes de fièvre sont surtout cosmopolites, la gravité des pathologies exotiques doit les faire rechercher en priorité. Le paludisme doit être évoqué devant toute fièvre en provenance d’Afrique subsaharienne. Le diagnostic repose sur l’association d’un frottis sanguin et d’un test sensible (goutte épaisse, polymerase chain reaction [PCR]) ou d’un test de diagnostic rapide (pour Plasmodium [P ]. falciparum ). Les critères clinicobiologiques de gravité sont essentiels pour orienter et traiter le patient. En cas d’accès non compliqué à P. falciparum , le traitement repose sur une thérapie combinée à base d’artémisinine (ACT), artéméther-luméfantrine ou arténimol-pipéraquine. Les accès graves sont traités par l’artésunate intraveineux, puis un ACT oral. Dengue, chikungunya et infection à virus Zika ont des caractéristiques cliniques communes (association fièvre-éruption-arthralgies, traitement symptomatique). En cas de dengue, il faut surveiller l’apparition de signes d’alerte qui pourraient faire craindre une évolution péjorative. Le chikungunya est grave en cas de transmission per partum, avec un risque d’encéphalite néonatale. Chez l’enfant, le Zika est a- ou peu symptomatique. Mais en cas d’infection pendant une grossesse, le risque est celui d’une embryofœtopathie. Le diagnostic de ces arboviroses repose sur la PCR à la phase aiguë et la sérologie secondairement. La symptomatologie de la typhoïde est peu spécifique, justifiant la pratique d’hémocultures systématiques devant une fièvre du retour. Son traitement repose sur les céphalosporines de troisième génération ou la ciprofloxacine, mais les résistances augmentent. Au total, la diversité des étiologies d’une fièvre de retour et la gravité potentielle des infections importées imposent une réflexion sur le parcours de soins de ces patients, en particulier vis-à-vis du risque de fièvre hémorragique.

Development of Mobile Laboratory for Viral Hemorrhagic Fever Detection in Africa

Background

A mobile laboratory transportable on commercial flights was developed to enable local response to viral hemorrhagic fever outbreaks.

Methods

The development progressed from use of mobile real-time reverse-transcription polymerase chain reaction to mobile real-time recombinase polymerase amplification. In this study, we describe various stages of the mobile laboratory development.

Results

A brief overview of mobile laboratory deployments, which culminated in the first on-site detection of Ebola virus disease (EVD) in March 2014, and their successful use in a campaign to roll back EVD cases in Conakry in the West Africa Ebola virus outbreak are described.

Conclusions

The developed mobile laboratory successfully enabled local teams to perform rapid disgnostic testing for viral hemorrhagic fever.

Metagenomic Next-Generation Sequencing of the 2014 Ebola Virus Disease Outbreak in the Democratic Republic of the Congo

We applied metagenomic next-generation sequencing (mNGS) to detect Zaire Ebola virus (EBOV) and other potential pathogens from whole-blood samples from 70 patients with suspected Ebola hemorrhagic fever during a 2014 outbreak in Boende, Democratic Republic of the Congo (DRC) and correlated these findings with clinical symptoms. Twenty of 31 patients (64.5%) tested in Kinshasa, DRC, were EBOV positive by quantitative reverse transcriptase PCR (qRT-PCR).

We applied metagenomic next-generation sequencing (mNGS) to detect Zaire Ebola virus (EBOV) and other potential pathogens from whole-blood samples from 70 patients with suspected Ebola hemorrhagic fever during a 2014 outbreak in Boende, Democratic Republic of the Congo (DRC) and correlated these findings with clinical symptoms. Twenty of 31 patients (64.5%) tested in Kinshasa, DRC, were EBOV positive by quantitative reverse transcriptase PCR (qRT-PCR). Despite partial degradation of sample RNA during shipping and handling, mNGS followed by EBOV-specific capture probe enrichment in a U.S. genomics laboratory identified EBOV reads in 22 of 70 samples (31.4%) versus in 21 of 70 (30.0%) EBOV-positive samples by repeat qRT-PCR (overall concordance = 87.1%). Reads from Plasmodium falciparum (malaria) were detected in 21 patients, of which at least 9 (42.9%) were coinfected with EBOV. Other positive viral detections included hepatitis B virus (n = 2), human pegivirus 1 (n = 2), Epstein-Barr virus (n = 9), and Orungo virus (n = 1), a virus in the Reoviridae family. The patient with Orungo virus infection presented with an acute febrile illness and died rapidly from massive hemorrhage and dehydration. Although the patient’s blood sample was negative by EBOV qRT-PCR testing, identification of viral reads by mNGS confirmed the presence of EBOV coinfection. In total, 9 new EBOV genomes (3 complete genomes, and an additional 6 ≥50% complete) were assembled. Relaxed molecular clock phylogenetic analysis demonstrated a molecular evolutionary rate for the Boende strain 4 to 10× slower than that of other Ebola lineages. These results demonstrate the utility of mNGS in broad-based pathogen detection and outbreak surveillance.

The Role of Reference Materials in the Research and Development of Diagnostic Tools and Treatments for Haemorrhagic Fever Viruses

Following the Ebola outbreak in Western Africa in 2013-16, a global effort has taken place for preparedness for future outbreaks. As part of this response, the development of vaccines, treatments and diagnostic tools has been accelerated, especially towards pathogens listed as likely to cause an epidemic and for which there are no current treatments. Several of the priority pathogens identified by the World Health Organisation are haemorrhagic fever viruses. This review provides information on the role of reference materials as an enabling tool for the development and evaluation of assays, and ultimately vaccines and treatments. The types of standards available are described, along with how they can be applied for assay harmonisation through calibration as a relative potency to a common arbitrary unitage system (WHO International Unit). This assures that assay metrology is accurate and robust. We describe reference materials that have been or are being developed for haemorrhagic fever viruses and consider the issues surrounding their production, particularly that of biosafety where the viruses require specialised containment facilities. Finally, we advocate the use of reference materials at early stages, including research and development, as this helps produce reliable assays and can smooth the path to regulatory approval.

Hitit Index to distinguish patients with and without Crimean-Congo hemorrhagic fever

Crimean-Congo hemorrhagic fever (CCHF) is fatal. Therefore, it is very important to use an inexpensive, easily accessible, quick and accurate screening index based on clinical signs and laboratory parameters to identify patients suspected of having CCHF. Laboratory test results on the day of hospitalization for 268 inpatients suspected of having CCHF were used to calculate the laboratory section of the Hitit Index, while 65 of these were also monitored daily during their hospital stay to develop the clinical section of the Hitit Index. Two-hundred CCHF-negative outpatients were also evaluated. One-hundred and forty-nine inpatients were CCHF-positive and 119 inpatients were CCHF-negative. The Hitit Index is 5.6 - (5.3*lymphocyte) - (0.02*fibrinogen) - (12*direct bilirubin) + (0.04*AST) + (0.32*hematocrit) - (0.5*neutrophil) - (0.07*CKD-EPI) - (0.001*CK) ± conjunctival hyperemia (+1.5 in conjunctival hyperemia presence and -1.5 in conjunctival hyperemia absence). In 65 inpatients monitored daily, Hitit Index results for CCHF-positive and negative inpatients were 6.10(1.90-12.30) and -5.35(-8.83- -1.95), while CCHF-negative outpatients were -10.99(-15.64- -6.95) (P < 0.001), respectively. On hospitalization day, just one inpatient was false-negative in 27 CCHF-positive inpatients, while four were false-positive among 38 CCHF-negative inpatients using the Hitit Index. After 24 h, just one inpatient was diagnosed falsely among 27 CCHF-positive and 38 CCHF-negative inpatients, and there was no change after 48 h. Management of patients living in endemic regions suspected of having CCHF could be achieved within minutes using the Hitit Index. Patients with Hitit Index less than zero can be monitored as outpatients, while patients with Hitit Index results above zero must be hospitalized in infectious diseases wards. This study was not registered since it was retrospective.

Conducta práctica ante un niño febril al regresar de un viaje

Las enfermedades más frecuentes al regresar de un viaje al extranjero son las infecciones gastrointestinales, las enfermedades febriles y los problemas dermatológicos. La evaluación de un niño febril al regreso de un viaje es clínica: verificación de los antecedentes y las vacunaciones, búsqueda de otros casos en contacto, signos funcionales y físicos, y características del viaje. Unas pruebas complementarias de rutina completan a menudo la evaluación para una orientación sindrómica. Si bien las causas de fiebre son, sobre todo, cosmopolitas, la gravedad de la enfermedad exótica obliga a buscarlas prioritariamente. El paludismo debe sospecharse ante una fiebre procedente de África subsahariana. El diagnóstico se basa en la asociación de un frotis sanguíneo y una prueba sensible (gota gruesa, reacción en cadena de la polimerasa [PCR]) o una prueba de diagnóstico rápido (para Plasmodium falciparum ). Los criterios clínico-biológicos de gravedad son esenciales para orientar y tratar al paciente. En caso de acceso no complicado por P. falciparum, el tratamiento se basa en un tratamiento combinado a base de artemisinina (ACT), arteméter-lumefantrina o artenimol-piperaquina. Los accesos graves se tratan con artesunato intravenoso, seguido de ACT oral. Dengue, chikungunya e infección por virus Zika tienen características clínicas comunes (fiebre-erupción-artralgias, tratamiento sintomático). En caso de dengue, conviene controlar la aparición de signos de alerta, que podrían hacer temer una evolución negativa. El chikungunya es grave en caso de transmisión en el parto, con un riesgo de encefalitis neonatal. En el niño, el Zika es asintomático o poco sintomático. Pero, en caso de infección durante el embarazo, el riesgo es el de una embriofetopatía. El diagnóstico de estas arbovirosis se basa en la PCR en la fase aguda y en la serología secundariamente. La sintomatología de la fiebre tifoidea es poco específica, lo cual justifica la práctica de hemocultivos sistemáticos ante una fiebre tras un viaje. Su tratamiento se basa en las cefalosporinas de tercera generación o el ciprofloxacino, pero las resistencias aumentan. En suma, la diversidad de las etiologías de una fiebre al regreso de un viaje y la potencial gravedad de las infecciones importadas imponen una reflexión sobre el proceso de tratamiento de estos pacientes, en especial en lo referente al riesgo de fiebre hemorrágica.

Flaviviruses and Kidney Diseases

The genus Flavivirus comprises approximately 73 viruses, which share several common aspects, such as dimension, structure, nucleic acid properties, and shape in electronic microscopy. Global incidence of flavivirus infection increased dramatically over the last decades, causing large outbreaks in several areas of the world. These viruses are expanding from endemic tropical and subtropical areas to previously nonendemic areas, affecting and causing diseases in millions of individuals worldwide and posing a formidable challenge to public health in several countries. The majority of clinically significant flavivirus-associated infections are mosquito borne (arboviruses-acronym for ARthropod-BOrne VIRUSES), such as dengue, yellow fever, Japanese encephalitis, Zika, and West Nile fever. Most diseases caused by flaviviruses are asymptomatic or manifest as self-limited, mild, undifferentiated febrile diseases. In a limited number of cases, these diseases may evolve to severe inflammatory, multisystem diseases, causing high morbidity and mortality. Some flaviviruses have been consistently identified in kidney tissue and urine and have been clinically associated with kidney diseases. In this review, we will provide an overview of the epidemiology, risk factors, kidney pathology, etiopathogenesis, and outcomes of acute and chronic kidney syndromes associated with dengue, yellow fever, Zika, and West Nile virus disease.

Tropical diseases in the ICU: A syndromic approach to diagnosis and treatment

Tropical infections form 20-30% of ICU admissions in tropical countries. Diarrheal diseases, malaria, dengue, typhoid, rickettsial diseases and leptospirosis are common causes of critical illness. Overlapping clinical features makes initial diagnosis challenging. A systematic approach involving (1) history of specific continent or country of travel, (2) exposure to specific environments (forests or farms, water sports, consumption of exotic foods), (3) incubation period, and (4) pattern of organ involvement and subtle differences in manifestations help in differential diagnosis and choice of initial empiric therapy. Fever, rash, hypotension, thrombocytopenia and mild derangement of liver function tests is seen in a majority of patients. Organ failure may lead to shock, respiratory distress, renal failure, hepatitis, coma, seizures, cardiac arrhythmias or hemorrhage. Diagnosis in some conditions is made by peripheral blood smear examination, antigen detection or detection of microbial nucleic acid by PCR. Tests that detect specific IgM antibody become positive only in the second week of illness. Initial therapy is often empiric; a combination of intravenous artesunate, ceftriaxone and either doxycycline or azithromycin would cover a majority of the treatable syndromes. Additional antiviral or antiprotozoal medications are required for some specific syndromes. Involving a physician specializing in tropical or travel medicine is helpful.