Hemophagocytic lymphohistiocytosis associated with parechovirus 3 infection

Cytokine Storm Syndrome Associated with Hemorrhagic Fever and Other Viruses

A wide variety of infections can trigger cytokine storm syndromes including those caused by bacteria, viruses, fungi and parasites. The most frequent viral trigger is Epstein-.Barr virus which is covered in Chapter 16. CSS associated with COVID-19 is also discussed separately (Chapter 22). This chapter will focus on other viruses including the hemorrhagic fever viruses, influenza, parainfluenza, adenovirus, parvovirus, hepatitis viruses, measles, mumps, rubella, enterovirus, parechovirus, rotavirus, human metapneumovirus and human T-lymphotropic virus. The published literature consists of many single case reports and moderate-sized case series reporting CSS, in most circumstances meeting the 2004 diagnostic criteria for hemophagocytic lymphohistiocytosis (HLH). There is no published clinical trial evidence specifically for management of HLH associated with these viruses. In some situations, patients received supportive therapy and blood product transfusions only but in most cases, they were treated with one or more of intravenous corticosteroids, intravenous immunoglobulin and/or etoposide. These were successful in many patients although in significant numbers progression of infection to CSS was associated with mortality.

Human Parechovirus: an Increasingly Recognized Cause of Sepsis-Like Illness in Young Infants

Human parechovirus (HPeV) is increasingly being recognized as a potentially severe viral infection in neonates and young infants. HPeV belongs to the family Picornaviridae and is currently divided into 19 genotypes. HPeV-1 is the most prevalent genotype and most commonly causes gastrointestinal and respiratory disease. HPeV-3 is clinically the most important genotype due to its association with severe disease in younger infants, which may partly be explained by its distinct virological properties. In young infants, the typical clinical presentation includes fever, severe irritability, and rash, often leading to descriptions of "hot, red, angry babies." Infants with severe central nervous system (CNS) infections are at an increased risk of long-term sequelae. Considering the importance of HPeV as a cause of severe viral infections in young infants, we recommend that molecular diagnostic techniques for early detection be included in the standard practice for the investigation of sepsis-like illnesses and CNS infections in this age group.

Human picornaviruses associated with neurological diseases and their neutralization by antibodies

Picornaviruses are the most commonly encountered infectious agents in mankind. They typically cause mild infections of the gastrointestinal or respiratory tract, but sometimes also invade the central nervous system. There, they can cause severe diseases with long-term sequelae and even be lethal. The most infamous picornavirus is poliovirus, for which significant epidemics of poliomyelitis were reported from the end of the nineteenth century. A successful vaccination campaign has brought poliovirus close to eradication, but neurological diseases caused by other picornaviruses have increasingly been reported since the late 1990s. In this review we focus on enterovirus 71, coxsackievirus A16, enterovirus 68 and human parechovirus 3, which have recently drawn attention because of their links to severe neurological diseases. We discuss the clinical relevance of these viruses and the primary role of humoral immunity in controlling them, and summarize current knowledge on the neutralization of such viruses by antibodies.

Extreme Hyperferritinemia in Dizygotic Twins With Human Parechovirus-3 Infection

Human parechovirus-3 has been associated with severe clinical manifestations in infants, such as sepsis-like illness and meningoencephalitis. Nevertheless, the vast majority of patients have a favorable outcome. We report the occurrence of this infection in dizygotic infants with extreme hyperferritinemia and a transient impairment of natural killer cell cytotoxicity.

Human Parechovirus 3: The Most Common Viral Cause of Meningoencephalitis in Young Infants

Human parechoviruses (HPeVs) were initially classified as echoviruses. HPeVs occur worldwide, comprising up to 17 genotypes. HPeV1 and HPeV3 are most common. Clinical disease varies somewhat among genotypes. HPeV1 causes mostly gastrointestinal infections. HPeV3's prominence is due to its causing sepsis syndromes and central nervous system (CNS) infections in young infants. Currently, HPeV3 is the most common single cause of aseptic meningitis/meningoencephalitis in infants less than 90 days old in North America, usually with biannual summer-fall seasonality. HPeV3 CNS infections usually lack cerebrospinal fluid pleocytosis. Mortality and sequelae are uncommon, usually accompanying initially severe or neurologically complicated acute illnesses.