Case report: severe neurological manifestation of Dobrava hantavirus infection

Square the Circle: Diversity of Viral Pathogens Causing Neuro-Infectious Diseases

Neuroinfections rank among the top ten leading causes of child mortality globally, even in high-income countries. The crucial determinants for successful treatment lie in the timing and swiftness of diagnosis. Although viruses constitute the majority of infectious neuropathologies, diagnosing and treating viral neuroinfections remains challenging. Despite technological advancements, the etiology of the disease remains undetermined in over half of cases. The identification of the pathogen becomes more difficult when the infection is caused by atypical pathogens or multiple pathogens simultaneously. Furthermore, the modern surge in global passenger traffic has led to an increase in cases of infections caused by pathogens not endemic to local areas. This review aims to systematize and summarize information on neuroinvasive viral pathogens, encompassing their geographic distribution and transmission routes. Emphasis is placed on rare pathogens and cases involving atypical pathogens, aiming to offer a comprehensive and structured catalog of viral agents with neurovirulence potential.

Clinical and laboratory features and factors predicting disease severity in pediatric patients with hemorrhagic fever with renal syndrome caused by Hantaan virus

The clinical features and factors associated with disease severity in children with hemorrhagic fever with renal syndrome (HFRS) have not been well characterized. This study analyzed the clinical and laboratory factors associated with disease severity in children with HFRS caused by Hantaan virus. Data in pediatric patients with HFRS were retrospectively collected from Xi'an Children's Hospital over a 9-year period. Independent factors associated with disease severity were identified. Nomogram predicting disease severity was constructed based on variables filtered by feature selection. In total, 206 children with HFRS were studied. Fever, digestive tract symptoms, headache, backache, bleeding, and renal injury signs were the common symptoms. Elevated white blood cell, reduced platelet, hematuria, proteinuria, coagulation abnormalities, increased blood urea nitrogen (BUN) and procalcitonin (PCT), decreased estimated glomerular filtration rate and low serum Na⁺ , Cl^- , and Ca²⁺ were the common laboratory findings. In the 206 patients, 21 patients had critical type disease and 4 patients (1.9%) died. Hydrothorax, hypotension and cerebral edema/cerebral herniation at hospital admission were independent clinical characteristics, and neutrophil %, prothrombin activity, PCT, BUN, and Ca²⁺ at hospital admission were independent laboratory factors associated with critical disease. Feature selection identified BUN, PCT and prothrombin time as independent factors related to critical disease. A nomogram integrating BUN and PCT at admission was constructed and calibration showed high accuracy for the probability prediction of critical disease. In conclusion, this study characterized the clinical and laboratory features and constructed a nomogram predicting disease severity in pediatric HFRS, providing references for disease severity evaluation in managing children HFRS.

Acute Hantavirus Infection Presenting with Fever and Altered Mentation in the Absence of Pulmonary or Renal Manifestations

Illness caused by hantaviruses is often severe and is typically characterized by diffuse pulmonary disease or renal insufficiency depending on the type of hantavirus. Here we report 2 cases of hantavirus infection that resulted in severe cognitive impairment but did not have any pulmonary or renal manifestations. These 2 cases may be indicative of previously underreported symptoms of hantavirus infection and might represent examples of hantavirus-related encephalopathy.

Hanta hemorrhagic fever with renal syndrome: A pathology in whose diagnosis kidney biopsy plays a major role (Review)

Hantavirus infection belongs to a group of zoonoses rare in the Balkan Peninsula, causing two major syndromes, depending on the viral serotype involved: Hemorrhagic fever with renal syndrome (HFRS) also known as endemic nephropathy and cardiopulmonary syndrome (CPS). Because there is no specific treatment or vaccine for this condition approved in the USA or Europe, the key to minimizing the risk of adverse progression to chronic kidney disease, secondary hypertension or even death is primarily the recognition and early diagnosis of this condition with prompt therapeutic intervention. The aim of this study was to review the literature data on the epidemiology, pathogenesis and management of this disease and to identify several aspects related to the difficulties encountered in diagnosing this pathology, taking into consideration that the disease is not endemic in this geographical area.

Central Nervous System and Ocular Manifestations in Puumala Hantavirus Infection

Puumala hantavirus (PUUV), carried and spread by the bank vole (Myodes glareolus), causes a mild form of hemorrhagic fever with renal syndrome (HFRS) called nephropathia epidemica (NE). Acute high fever, acute kidney injury (AKI), thrombocytopenia, and hematuria are typical features of this syndrome. In addition, headache, blurred vision, insomnia, vertigo, and nausea are commonly associated with the disease. This review explores the mechanisms and presentations of ocular and central nervous system involvement in acute NE.

Heterozygous TLR3 Mutation in Patients with Hantavirus Encephalitis

Puumala hantavirus (PUUV) hemorrhagic fever with renal syndrome (HFRS) is common in Northern Europe; this infection is usually self-limited and severe complications are uncommon. PUUV and other hantaviruses, however, can rarely cause encephalitis. The pathogenesis of these rare and severe events is unknown. In this study, we explored the possibility that genetic defects in innate anti-viral immunity, as analogous to Toll-like receptor 3 (TLR3) mutations seen in HSV-1 encephalitis, may explain PUUV encephalitis. We completed exome sequencing of seven adult patients with encephalitis or encephalomyelitis during acute PUUV infection. We found heterozygosity for the TLR3 p.L742F novel variant in two of the seven unrelated patients (29%, p = 0.0195). TLR3-deficient P2.1 fibrosarcoma cell line and SV40-immortalized fibroblasts (SV40-fibroblasts) from patient skin expressing mutant or wild-type TLR3 were tested functionally. The TLR3 p.L742F allele displayed low poly(I:C)-stimulated cytokine induction when expressed in P2.1 cells. SV40-fibroblasts from three healthy controls produced increasing levels of IFN-λ and IL-6 after 24 h of stimulation with increasing concentrations of poly(I:C), whereas the production of the cytokines was impaired in TLR3 L742F/WT patient SV40-fibroblasts. Heterozygous TLR3 mutation may underlie not only HSV-1 encephalitis but also PUUV hantavirus encephalitis. Such possibility should be further explored in encephalitis caused by these and other hantaviruses.

Two clinical cases of renal syndrome caused by Dobrava/Saaremaa hantaviruses imported to the Netherlands from Poland and Belarus, 2012-2014

We report the rare event of two imported cases in the Netherlands presenting with renal syndrome caused by Dobrava (DOBV)/Saaremaa (SAAV) hantaviruses. DOBV/SAAV hantaviruses are not circulating in the Netherlands and their clinical manifestation is typically more severe than that of the endemic Puumala virus (PUUV). This report aims to increase awareness among healthcare professionals and diagnostic laboratories to consider different hantaviruses as a cause of renal failure.

Hemorrhagic fever with renal syndrome-related encephalopathy: magnetic resonance imaging findings

OBJECTIVE

To report the incidence and findings of brain magnetic resonance imaging (MRI) in patients with hemorrhagic fever with renal syndrome (HFRS)-related encephalopathy along with its clinical course.

METHODS

Medical records and brain MRI were reviewed from January 2004 to January 2013. The final cohort consisted of 145 patients. Brain MRI findings were correlated with associated clinical stage of disease.

RESULTS

The MRI findings associated with clinical course of HFRS-related encephalopathy were posterior reversible encephalopathy syndrome pattern (n=3) in oliguric phase and splenial lesion pattern (n=1) in febrile phase.

CONCLUSIONS

Brain MRI findings in HFRS-related encephalopathy may be associated with the clinical course of HFRS.

Lethal disease in infant and juvenile Syrian hamsters experimentally infected with Imjin virus, a newfound crocidurine shrew-borne hantavirus

To gain insights into the pathogenicity of Imjin virus (MJNV), a newfound hantavirus isolated from the Ussuri white-toothed shrew (Crocidura lasiura), groups of Syrian hamsters (Mesocricetus auratus) of varying ages (<1, 5, 10, 14, 21, 35 and 56 days) were inoculated by the intraperitoneal route with 1000 pfu of MJNV strains 04-55 and 05-11. MJNV-infected Syrian hamsters, aged 21 days or less, exhibited reduced activity, weight loss, respiratory distress, hind-limb paralysis and seizures. Death ensued 1 to 6 days after onset of clinical disease. MJNV RNA was detected in brain and other major organs by RT-PCR and real time-PCR. Histopathological examination showed alveolar hemorrhage, interstitial pneumonia and severe pulmonary congestion; focal hepatic necrosis and portal inflammation; and acute meningoencephalitis. By immunohistochemistry, MJNV antigen was detected in pulmonary microvascular endothelial cells and glial cells. Older hamsters (35 and 56 days of age) developed subclinical infection without histopathological changes. Future studies are warranted to determine the pathophysiologic bases for the differential age susceptibility of Syrian hamsters to lethal MJNV disease.

Hantavirus infections in Europe and their impact on public health

Hantaviruses (genus Hantavirus, family Bunyaviridae) are enveloped tri-segmented negative-stranded RNA viruses each carried by a specific rodent or insectivore host species. Several different hantaviruses known to infect humans circulate in Europe. The most common is Puumala (PUUV) carried by the bank vole; another two important, genetically closely related ones are Dobrava-Belgrade (DOBV) and Saaremaa viruses (SAAV) carried by Apodemus mice (species names follow the International Committee on Taxonomy of Viruses nomenclature). Of the two hantaviral diseases, hemorrhagic fever with renal syndrome (HFRS) and hantaviral cardiopulmonary syndrome, the European viruses cause only HFRS: DOBV with often severe symptoms and a high case fatality rate, and PUUV and SAAV more often mild disease. More than 10,000 HFRS cases are diagnosed annually in Europe and in increasing numbers. Whether this is because of increasing recognition by the medical community or due to environmental factors such as climate change, or both, is not known. Nevertheless, in large areas of Europe, the population has a considerable seroprevalence but only relatively few HFRS cases are reported. Moreover, no epidemiological data are available from many countries. We know now that cardiac, pulmonary, ocular and hormonal disorders are, besides renal changes, common during the acute stage of PUUV and DOBV infection. About 5% of hospitalized PUUV and 16%-48% of DOBV patients require dialysis and some prolonged intensive-care treatment. Although PUUV-HFRS has a low case fatality rate, complications and long-term hormonal, renal, and cardiovascular consequences commonly occur. No vaccine or specific therapy is in general use in Europe. We conclude that hantaviruses have a significant impact on public health in Europe.

Hantavirus protein interactions regulate cellular functions and signaling responses

Rodent-borne pathogenic hantaviruses cause two severe and often lethal zoonotic diseases: hemorrhagic fever with renal syndrome (HFRS) in Eurasia and hantavirus cardiopulmonary syndrome (HCPS) in the Americas. Currently, no US FDA-approved therapeutics or vaccines are available for HFRS/HCPS. Infections with hantaviruses are not lytic, and it is currently not known exactly why infections in humans cause disease. A better understanding of how hantaviruses interfere with normal cell functions and activation of innate and adaptive immune responses might provide clues to future development of specific treatment and/or vaccines against hantavirus infection. In this article, the current knowledge regarding immune responses observed in patients, hantavirus interference with cellular proteins and signaling pathways, and possible approaches in the development of therapeutics are discussed.

Hantavirus pulmonary syndrome: encephalitis caused by virus Andes

Hemorrhagic fever with renal syndrome and hantavirus pulmonary syndrome (HPS) are rodent-borne emerging diseases caused by members of the genus Hantavirus, family Bunyaviridae. Some species of hantavirus may cause encephalitis, but this is the first report in Andes virus associated to HPS.

Subarachnoid hemorrhage associated with epidemic hemorrhagic fever: a rare case report

Nervous system injuries associated with epidemic hemorrhagic fever (EHF) are not rarely seen. However, cerebrovascular disease arising from EHF is rarely reported in the literature. A 50-year-old male patient suffered from subarachnoid hemorrhage (SAH). No abnormal condition was found in intracranial vascular digital subtraction angiography (DSA). But, this patient presented with positive hantavirus-IgM and IgG, with typical clinical process, which lead to the diagnosis of EHF followed by SAH. To our knowledge, SAH associated with EHF has not been previously reported. A meticulous assessment of EHF patients with a serious condition had one or more central nervous system (CNS) abnormalities, such as sudden headache, vomiting, confusion, meningismus, and convulsions, which is necessary for diagnosing and giving timely treatment to improve the prognosis.

Reversible splenium lesion of the corpus callosum in hemorrhagic fever with renal failure syndrome

This is the first case of virus-associated encephalitis/encephalopathy in which the pathogen was Hantaan virus. A 53-yr-old man presented fever, renal failure and a hemorrhagic tendency and he was diagnosed with hemorrhagic fever with renal failure syndrome (HFRS). In the course of his illness, mild neurologic symptoms such as dizziness and confusion developed and magnetic resonance images revealed a reversible lesion in the splenium of the corpus callosum. This case suggests that HFRS patients with neurologic symptoms like dizziness and mental slowing should be considered to have structural brain lesions and to require brain imaging studies.

A global perspective on hantavirus ecology, epidemiology, and disease

Hantaviruses are enzootic viruses that maintain persistent infections in their rodent hosts without apparent disease symptoms. The spillover of these viruses to humans can lead to one of two serious illnesses, hantavirus pulmonary syndrome and hemorrhagic fever with renal syndrome. In recent years, there has been an improved understanding of the epidemiology, pathogenesis, and natural history of these viruses following an increase in the number of outbreaks in the Americas. In this review, current concepts regarding the ecology of and disease associated with these serious human pathogens are presented. Priorities for future research suggest an integration of the ecology and evolution of these and other host-virus ecosystems through modeling and hypothesis-driven research with the risk of emergence, host switching/spillover, and disease transmission to humans.