Epidemiological Surveillance of Viral Hemorrhagic Fevers With Emphasis on Clinical Virology.

This article will outline surveillance approaches for viral hemorrhagic fevers. Specific methods for surveillance of clinical samples will be emphasized. Separate articles will describe methods for surveillance of rodent-borne viruses (roboviruses) and arthropod-borne viruses (arboviruses). Since the appearance of hantaviruses and arenaviruses in the Americas, more than 30 different species in each group have been established, and therefore they have become the most frequently emerging viruses. Flaviviruses such as yellow fever and dengue viruses, although easier to recognize, are also more widely spread and therefore considered a very important public health issue, particularly for under-developed countries. On the other hand, marburgviruses and ebolaviruses, previously thought to be restricted to the African continent, have recently been shown to be more global. For many of these agents virus isolation has been a challenging task: trapping the specific vectors (mosquitoes and ticks), and reservoirs (rodents and bats), or obtaining the samples from suspected clinical human cases demands special protective gear, uncommon devices (respirators), special facilities (BSL-3 and 4), and particular skills to recognize the slow and inapparent cytopathic effects in cell culture. Alternatively, serological and molecular approaches have been very helpful in discovering and describing newly emerging viruses in many areas where the previous resources are unavailable. Unfortunately, in many cases, detailed studies have been performed only after outbreaks occur, and then active surveillance is needed to prevent viral dissemination in human populations.

Infections by Leptospira interrogans, Seoul virus, and Bartonella spp. among Norway rats (Rattus norvegicus) from the urban slum environment in Brazil.

Norway rats (Rattus norvegicus) are reservoir hosts for zoonotic pathogens that cause significant morbidity and mortality in humans. Studies evaluating the prevalence of zoonotic pathogens in tropical Norway rat populations are rare, and data on co-infection with multiple pathogens are nonexistent. Herein, we describe the prevalence of leptospiral carriage, Seoul virus (SEOV), and Bartonella spp. infection independently, in addition to the rates of co-infection among urban, slum-dwelling Norway rats in Salvador, Brazil, trapped during the rainy season from June to August of 2010. These data were complemented with previously unpublished Leptospira and SEOV prevalence information collected in 1998. Immunofluorescence staining of kidney impressions was used to identify Leptospira interrogans in 2010, whereas isolation was used in 1998, and western blotting was used to detect SEOV antibodies in 2010, whereas enzyme-linked immunosorbent assay (ELISA) was used in 1998: in 2010, Bartonella spp. were isolated from a subsample of rats. The most common pathogen in both years was Leptospira spp. (83%, n=142 in 1998, 63%, n=84 in 2010). SEOV was detected in 18% of individuals in both 1998 and 2010 (n=78 in 1998; n=73 in 2010), and two species of Bartonella were isolated from 5 of 26 rats (19%) tested in 2010. The prevalence of all agents increased significantly with rat mass/age. Acquisition of Leptospira spp. occurred at a younger mass/age than SEOV and Bartonella spp. infection, suggesting differences in the transmission dynamics of these pathogens. These data indicate that Norway rats in Salvador serve as reservoir hosts for all three of these zoonotic pathogens and that the high prevalence of leptospiral carriage in Salvador rats poses a high degree of risk to human health.

Hantavirus pulmonary syndrome.

Hantavirus pulmonary syndrome (HPS) is a severe disease characterized by a rapid onset of pulmonary edema followed by respiratory failure and cardiogenic shock. The HPS associated viruses are members of the genus Hantavirus, family Bunyaviridae. Hantaviruses have a worldwide distribution and are broadly split into the New World hantaviruses, which includes those causing HPS, and the Old World hantaviruses [including the prototype Hantaan virus (HTNV)], which are associated with a different disease, hemorrhagic fever with renal syndrome (HFRS). Sin Nombre virus (SNV) and Andes virus (ANDV) are the most common causes of HPS in North and South America, respectively. Case fatality of HPS is approximately 40%. Pathogenic New World hantaviruses infect the lung microvascular endothelium without causing any virus induced cytopathic effect. However, virus infection results in microvascular leakage, which is the hallmark of HPS. This article briefly reviews the knowledge on HPS-associated hantaviruses accumulated since their discovery, less than 20 years ago.

Hantavirus nephropathy as a pseudo-import pathology from Ecuador.

We report a case of hantavirus infection (nephropathia epidemica) diagnosed in a Belgian backpacker returning from a trekking expedition in Ecuador, after likely heavy exposure to rodents. Because of epidemiological inconsistency, molecular investigation was performed and revealed a Puumala infection acquired during very limited exposure in Belgium upon return.

[The hantaviruses causing hemorrhagic fever with renal syndrome and pulmonary syndrome]. / Los hantavirus causantes de la fiebre hemorrágica con síndrome renal y del síndrome pulmonar.

The goal of this review is to provide basic information on hantaviruses as causative agents of Hemorrhagic Fever with Renal Syndrome (HFRS) and Hantavirus Pulmonary Syndrome (HPS), two zoonotic diseases widely distributed in Asia/Europe, and the American continent, respectively. Hantaviruses are rodent-borne and transmitted to humans by direct contact with infected rodents or their secretions (urine, feces and saliva). Both, HFRS and HPS share some clinical aspects, however, hemorrhage and renal failure are the hallmark of HFRS, while respiratory problems are distinctive signs and symptoms of patients with HPS. Studies on hantavirus infection in rodents from Mexico are included, some recomendations to prevent or avoid contact with rodents are mentioned, and some determinant ecologic factors of hantaviruses distribution and their natural rodents, are also included.

Los hantavirus causantes de la fiebre hemorrágica con síndrome renal y del síndrome pulmonar / The hantaviruses causing hemorrhagic fever with renal syndrome and pulmonary syndrome

Este trabajo de revisión se enfoca en el análisis de la información básica sobre los hantavirus, agentes causales de dos enfermedades importantes en salud pública: la fiebre hemorrágica con síndrome renal (FHSR) y el síndrome pulmonar por hantavirus (SPH), dos zoonosis distribuidas en Asia/Europa y el continente americano, respectivamente. Los hantavirus se transmiten al hombre a través de la manipulación y contacto directos de roedores infectados o tejidos y secreciones (orina, heces y saliva). La FHSR y el SPH comparten algunas características clínicas, aunque las hemorragias y la afectación renal son propias de la FHSR,y los problemas respiratorios del SPH. Se aportan algunos datos sobre estudios realizados en México sobre hantavirus y se mencionan las condiciones ecológicas vinculadas con la distribución de los virus y sus reservorios naturales, así como algunas medidas para evitar o reducir el riesgo de infección.

The goal of this review is to provide basic information on hantaviruses as causative agents of Hemorrhagic Fever with Renal Syndrome (HFRS) and Hantavirus Pulmonary Syndrome (HPS), two zoonotic diseases widely distributed in Asia/Europe, and the American continent, respectively. Hantaviruses are rodent-borne and transmitted to humans by direct contact with infected rodents or their secretions (urine, feces and saliva). Both, HFRS and HPS share some clinical aspects, however, hemorrhage and renal failure are the hallmark of HFRS, while respiratory problems are distinctive signs and symptoms of patients with HPS. Studies on hantavirus infection in rodents from Mexico are included, some recomendations to prevent or avoid contact with rodents are mentioned, and some determinant ecologic factors of hantaviruses distribution and their natural rodents, are also included.

Hantaviroses / Hantaviruses

As hantaviroses constituem infecções zoonóticas amplamente distribuídas em todo o mundo. A febre hemorrágica com síndrome renal mostra-se endêmica na Asia e Europa, acometendo milharea de pessoas anualmente. A síndrome cardiopulmonar pelo hantavírus, reconhecida como entidade clínica desde 1993, representa o protótipo das doenças emergentes e encontra-se distribuída em diversos países do continente americano, inclusive o Brasil. Ambas säo transmitidas ao homem através da inalaçäo de partículas virais eliminadas nas fezes e urina de roedores domésticos e silvestres. Trata-se de doenças sistêmicas febris que podem acometer vários órgäos, destacando-se o rim na febre hemorrágica com síndrome renal e os pulmöes e o coraçäo na síndrome cardiopulmonar. A taxa de letalidade da hantavirose americana alcança 50 por cento. Diagnostica-se as hantaviroses através de provas sorológicas imunoenzimáticas ao identificar-se anticorpos específicos das classes IgM e IgG. Näo há tratamento específico. Recomenda-se hidrataçäo cuidadosa, indicaçäo precoce de diálise nas formas renais e administraçäo de drogas vasoativas nos períodos de hipotensäo e choque. A administraçäo de corticoesteróides e da ribavirina está sendo avaliada em estudos controlados. O número de casos dessas viroses tem crescido no Brasil ano a ano, e cumpre alertar os profissionais de saúde sobre a ocorrência dessas entidades nos vários estados do país, possibilitando diagnóstico precoce e tratamento adequado nos casos suspeitos da doença