Diagnosis of hantavirus infection in humans and rodents in Ribeirão Preto, State of São Paulo, Brazil

Synthesizing the connections between environmental disturbances and zoonotic spillover

Zoonotic spillover is a phenomenon characterized by the transfer of pathogens between different animal species. Most human emerging infectious diseases originate from non-human animals, and human-related environmental disturbances are the driving forces of the emergence of new human pathogens. Synthesizing the sequence of basic events involved in the emergence of new human pathogens is important for guiding the understanding, identification, and description of key aspects of human activities that can be changed to prevent new outbreaks, epidemics, and pandemics. This review synthesizes the connections between environmental disturbances and increased risk of spillover events based on the One Health perspective. Anthropogenic disturbances in the environment (e.g., deforestation, habitat fragmentation, biodiversity loss, wildlife exploitation) lead to changes in ecological niches, reduction of the dilution effect, increased contact between humans and other animals, changes in the incidence and load of pathogens in animal populations, and alterations in the abiotic factors of landscapes. These phenomena can increase the risk of spillover events and, potentially, facilitate new infectious disease outbreaks. Using Brazil as a study model, this review brings a discussion concerning anthropogenic activities in the Amazon region and their potential impacts on spillover risk and spread of emerging diseases in this region.

Posterior Reversible Encephalopathy Syndrome in a Patient with Hemorrhagic Fever with Renal Syndrome

We presently report the case of hantavirus infection in a 45-year-old male who was hospitalized to our clinic of infectious diseases, with fever, myalgia, vomiting, nausea, headache, and abdominal pain. The physical findings included hepatomegaly, splenomegaly, rash, and conjunctival injection. Eight days before the start of complaints, the patient has cut trees in the mountain. An acute renal failure was observed with an oliguria and an increase of serum creatinine and blood urea nitrogen. Urinalysis shows albuminuria and hematuria. Elevations of amylase, lipase, and liver enzymes levels, low serum albumin level, and thrombocytopenia were observed. A positive ELISA test for hantavirus IgM/IgG antibodies confirmed hemorrhagic fever with renal syndrome. On the third day of hospitalization, the patient had seizures. The unenhanced head computed tomography (CT) performed after seizures showed subcortical bilateral hypodensities within frontal, parietal, and occipital regions corresponding to areas of increased signal intensity in magnetic resonance imaging (MRI) associated with cerebral edema in posterior reversible encephalopathy syndrome (PRES). The treatment consisted of supportive therapy. The patient underwent another head MRI with contrast enhancement after 2 months, which resulted normal.

Does the widely distributed rodent Calomys tener (Cricetidae: Sigmodontinae) constitute a single evolutionary unit?

The nominal species Calomystener (Winge, 1887) ranges broadly in open lands of the Caatinga, Cerrado, Pantanal and Mata Atlântica of Brazil, and was recently reported from the Pampas of southern Brazil, and in the Selva Paranaense of eastern Paraguay and northeastern Argentina. This rodent can be infected with the pathogenic Araraquara hantavirus in Brazil. Given that most epidemiological studies have not taken into account updated taxonomic findings of their rodent hosts, in this study, we obtained sequence data of the Cyt-b and COI genes of specimens of C.tener from 22 different geographical localities from throughout the currently known distribution of the species (including individuals from Argentina, Paraguay, Bolivia, and Brazil) to test if it constitutes a single genetic unit or if it presents genetic discontinuities that may represent different evolutionary lineages. Phylogenetic analyses including several species of Calomys recovered several clades with strong support. Regarding C.tener, it is recovered as sister to the node that cluster C.laucha (Fischer, 1814) sensu lato, C.expulsus (Lund, 1841) and species in the C.callosus (Rengger, 1830) species complex. At the intraspecific level there are no genetic gaps among haplotypes of C.tener that could suggest more than one species. The recent captures in the Pampas of southern Brazil and in the Selva Paranaense suggest that the species may be colonizing new geographic areas.

Quick electrochemical immunoassay for hantavirus detection based on biochar platform

This work describes the first method using biochar (BC) as carbonaceous platform for immunoassay application. BC is a highly functionalized material obtained through biomass pyrolysis under controlled conditions. Due to the highly functionalized surface, covalent binding between BC and biomolecules can be performed by EDC/NHS conjugation. The application of the modified electrode was done with Hantavirus, that are etiologic agents mainly transmitted by wild rodents. Among its pathologies Hantavirus Cardiopulmonary Syndrome (HCPS) arises at Americas, caused by Hantavirus Araucária and reaches 40% lethality. The diagnostic is based on the presence of specific hantavirus nucleoprotein (Np), under viremic condition or IgG2b antibodies (Ab), during first symptoms. The results presented a device sensitivity of 5.28 μA dec^-1 and a LOD of 0.14 ng mL^-1 to the Np detection, ranging from 5.0 ng mL^-1 to 1.0 μg mL^-1, the Ab detection works as qualitative type sensor above 200 ng mL^-1. Both sensors were evaluated its selectivity and serum samples; selectivity against Gumboro disease, VP2 protein, and antibody IgG2a against Yellow fever disease (YF), respectively. So, the devices here proposed are promising tool suitable for both rodent and human hantavirus clinical surveys.

Expansion of the range of Necromys lasiurus (Lund, 1841) into open areas of the Atlantic Forest biome in Rio de Janeiro state, Brazil, and the role of the species as a host of the hantavirus

Necromys lasiurus is a generalist rodent that is thought to be the main reservoir of the Araraquara hantavirus, which causes Hantavirus Pulmonary Syndrome, in the Brazilian Cerrado savanna. This species occurs naturally in the open habitats of the Cerrado, Pantanal and Caatinga biomes, where it often occurs at high densities, although the distribution of the species has recently been observed expanding into the Brazilian state of Rio de Janeiro. This study aimed to map the occurrence of N. lasiurus within the Atlantic Forest of Rio de Janeiro state and discuss the potential role of the species as a reservoir of the Araraquara hantavirus in these areas. The study was based on a comprehensive literature search and four expeditions for the collection of specimens in the state of Rio de Janeiro. The data were used to predict the distribution of N. lasiurus, confirm the distribution of the species in the state, and detect the rates of hantavirus infection in these rodents. Necromys lasiurus has been recorded at 16 localities in 10 municipalities of Rio de Janeiro state. The relative abundance of N. lasiurus was low at all localities, except for the REBIO Poço das Antas and APA-BRSJ, two protected areas. Necromys lasiurus was associated primarily with landscapes dominated by farmland (plantations or pasture) at relatively low altitudes in the vicinity of bodies of water. A total of 204 serum samples were collected, but none were reactive for hantavirus. The distribution of N. lasiurus is expanding into many areas of the anthropogenic matrix, but it is not usually either abundant or dominant in these areas. The relatively reduced abundance of N. lasiurus in Rio de Janeiro and the lack of infection in all the areas investigated indicate that it is unlikely to be a reservoir of hantavirus in this region in the near future.

Natural infection of Neotropical bats with hantavirus in Brazil

Bats (Order: Chiroptera) harbor a high diversity of emerging pathogens presumably because their ability to fly and social behavior favor the maintenance, evolution, and dissemination of these pathogens. Until 2012, there was only one report of the presence of Hantavirus in bats. Historically, it was thought that these viruses were harbored primarily by rodent and insectivore small mammals. Recently, new species of hantaviruses have been identified in bats from Africa and Asia continents expanding the potential reservoirs and range of these viruses. To assess the potential of Neotropical bats as hosts for hantaviruses and its transmission dynamics in nature, we tested 53 bats for active hantaviral infection from specimens collected in Southeastern Brazil. Part of the hantaviral S segment was amplified from the frugivorous Carollia perspicillata and the common vampire bat Desmodus rotundus. DNA sequencing showed high similarity with the genome of Araraquara orthohantavirus (ARQV), which belongs to one of the more lethal hantavirus clades (Andes orthohantavirus). ARQV-like infection was detected in the blood, urine, and organs of D. rotundus. Therefore, we describe a systemic infection in Neotropical bats by a human pathogenic Hantavirus. We also propose here a schematic transmission dynamics of hantavirus in the study region. Our results give insights to new, under-appreciated questions that need to be addressed in future studies to clarify hantavirus transmission in nature and avoid hantavirus outbreaks.

Co-circulation of Araraquara and Juquitiba Hantavirus in Brazilian Cerrado

Hantavirus cardiopulmonary syndrome is an emerging serious disease in the Americas, transmitted from wild rodents to humans through inhalation of aerosol containing virus. Herein, we characterized two distinct hantaviruses circulating in rodent species form Central Plateau, Midwestern region of Brazil in the Cerrado (savanna-like) biome, an area characterized by small trees and grasses adapted to climates with long dry periods. In this study, we identified the co-circulation of the Araraquara virus and a possible new lineage of the Juquitiba virus (JUQV) in Oligoryzomys nigripes. The implications of co-circulation are still unknown, but it can be the key for increasing viral diversity or emergence of new species through spillover or host switching events leading to co-infection and consequently recombination or reassortment between different virus species. Phylogenetic analyses based on the complete S segment indicated that, alongside with Oligoryzomys mattogrossae rodents, O. nigripes species could also have a whole as JUQV reservoir in the Cerrado biome. Although these rodents' species are common in the Cerrado biome, they are not abundant demonstrating how complex and different hantavirus enzootic cycles can be in this particular biome.

Global Diversity and Distribution of Hantaviruses and Their Hosts

Rodents represent 42% of the world's mammalian biodiversity encompassing 2,277 species populating every continent (except Antarctica) and are reservoir hosts for a wide diversity of disease agents. Thus, knowing the identity, diversity, host-pathogen relationships, and geographic distribution of rodent-borne zoonotic pathogens, is essential for predicting and mitigating zoonotic disease outbreaks. Hantaviruses are hosted by numerous rodent reservoirs. However, the diversity of rodents harboring hantaviruses is likely unknown because research is biased toward specific reservoir hosts and viruses. An up-to-date, systematic review covering all known rodent hosts is lacking. Herein, we document gaps in our knowledge of the diversity and distribution of rodent species that host hantaviruses. Of the currently recognized 681 cricetid, 730 murid, 61 nesomyid, and 278 sciurid species, we determined that 11.3, 2.1, 1.6, and 1.1%, respectively, have known associations with hantaviruses. The diversity of hantaviruses hosted by rodents and their distribution among host species supports a reassessment of the paradigm that each virus is associated with a single-host species. We examine these host-virus associations on a global taxonomic and geographical scale with emphasis on the rodent host diversity and distribution. Previous reviews have been centered on the viruses and not the mammalian hosts. Thus, we provide a perspective not previously addressed.

Hantavirus pulmonary syndrome and rodent reservoirs in the savanna-like biome of Brazil's southeastern region

This paper describes the diversity of rodent fauna in an area endemic for hantavirus cardiopulmonary syndrome (HCPS) in Brazil, the population dynamics and the relationship of rodents with hantavirus in the Cerrado (savanna-like) biome. Additionally, an analysis is made of the partial S segment sequences of the hantaviruses obtained from serologically confirmed human HCPS cases and from rodent specimens. Rodents were collected during four campaigns. Human serum samples were collected from suspected cases of HCPS at hospitals in the state of Minas Gerais. The samples antibody-reactive by ELISA were processed by RT-PCR. The PCR product was amplified and sequenced. Hantavirus was detected only in Necromys lasiurus, the wild rodent species most prevalent in the Cerrado biome (min-max: 50-83·7%). All the six human serum samples were hantavirus seropositive and five showed amplified PCR products. The analysis of the nucleotide sequences showed the circulation of a single genotype, the Araraquara hantavirus. The environmental changes that have occurred in the Cerrado biome in recent decades have favoured N. lasiurus in interspecific competition of habitats, thus increasing the risk of contact between humans and rodent species infected with hantavirus. Our data corroborate the definition of N. lasiurus as the main hantavirus reservoir in the Cerrado biome.

Detection of different South American hantaviruses

Hantaviruses are the etiologic agents of Hemorrhagic Fever with Renal Syndrome (HFRS) in Old World, and Hantavirus Pulmonary Syndrome (HPS)/Hantavirus Cardiopulmonary Syndrome (HCPS), in the New World. Serological methods are the most common approach used for laboratory diagnosis of HCPS, however theses methods do not allow the characterization of viral genotypes. The polymerase chain reaction (PCR) has been extensively used for diagnosis of viral infections, including those caused by hantaviruses, enabling detection of few target sequence copies in the sample. However, most studies proposed methods of PCR with species-specific primers. This study developed a simple and reliable diagnostic system by RT-PCR for different hantavirus detection. Using new primers set, we evaluated human and rodent hantavirus positive samples of various regions from Brazil. Besides, we performed computational analyzes to evaluate the detection of other South American hantaviruses. The diagnostic system by PCR proved to be a sensible and simple assay, allowing amplification of Juquitiba virus, Araraquara virus, Laguna Negra virus, Rio Mamore virus and Jabora virus, beyond of the possibility of the detecting Andes, Anajatuba, Bermejo, Choclo, Cano Delgadito, Lechiguanas, Maciel, Oran, Pergamino and Rio Mearim viruses. The primers sets designed in this study can detect hantaviruses from almost all known genetics lineages in Brazil and from others South America countries and also increases the possibility to detect new hantaviruses. These primers could easily be used both in diagnosis of suspected hantavirus infections in humans and also in studies with animals reservoirs.

Evidence of Hantavirus Infection Among Bats in Brazil

Hantaviruses are zoonotic viruses harbored by rodents, bats, and shrews. At present, only rodent-borne hantaviruses are associated with severe illness in humans. New species of hantaviruses have been recently identified in bats and shrews greatly expanding the potential reservoirs and ranges of these viruses. Brazil has one of the highest incidences of hantavirus cardiopulmonary syndrome in South America, hence it is critical to know what is the prevalence of hantaviruses in Brazil. Although much is known about rodent reservoirs, little is known regarding bats. We captured 270 bats from February 2012 to April 2014. Serum was screened for the presence of antibodies against a recombinant nucleoprotein (rN) of Araraquara virus (ARAQV). The prevalence of antibody to hantavirus was 9/53 with an overall seroprevalence of 17%. Previous studies have shown only insectivorous bats to harbor hantavirus; however, in our study, of the nine seropositive bats, five were frugivorous, one was carnivorous, and three were sanguivorous phyllostomid bats.

Co-circulation in a single biome of the Juquitiba and Araraquara hantavirus detected in human sera in a sub-tropical region of Brazil

Hantaviruses is an emerging infectious disease. Although HCPS has been reported in several regions of Brazil, more cases of HCPS have recently been reported in Minas Gerais than in any other state. In 2009, we analyzed 27 samples presenting antibodies against hantaviruses. These samples originated from 688 symptomatic patients, as determined based on the Hemorrhagic Fever Protocol. A subsequent SYBR Green-based real-time RT-PCR demonstrated the presence of the virus in 22 of the samples. Among the RT-PCR-positive samples, 17 were analyzed using DNA sequencing; these sequences were compared with others deposited in GenBank and showed similarity with the Araraquara and Juquitiba virus clusters. This work describe the detection of Juquitiba virus, including three fatal cases, in Minas Gerais state, furthermore, showed that it is feasible to characterize the circulating strains using a small fragment of S segment. Finally, the results suggest the co-circulation of Araraquara and Juquitiba virus in a single biome in Minas Gerais state.

Serologic survey on hantavirus in blood donors from the state of Santa Catarina, Brazil

Emergent diseases such as Hantavirus Cardio-pulmonary Syndrome (HCPS) are able to create a significant impact on human populations due to their seriousness and high fatality rate. Santa Catarina, located in the South of Brazil, is the leading state for HCPS with 267 reported cases from 1999 to 2011. We present here a serological survey on hantavirus in blood donors from different cities of the state of Santa Catarina, with an IgG-ELISA using a recombinant nucleocapsid protein from Araraquara hantavirus as an antigen. In total, 314 donors from blood banks participated in the study, geographically covering the whole state. Among these, 14 individuals (4.4%) had antibodies to hantavirus: four of 50 (8% positivity) from Blumenau, four of 52 (7.6%) from Joinville, three of 50 (6%) from Florianópolis, two of 50 (4%) from Chapecó and one of 35 (2.8%) from Joaçaba. It is possible that hantaviruses are circulating across almost the whole state, with important epidemiological implications. Considering that the seropositive blood donors are healthy individuals, it is possible that hantaviruses may be causing unrecognized infections, which are either asymptomatic or clinically nonspecific, in addition to HCPS. It is also possible that more than one hantavirus type could be circulating in this region, causing mostly benign infections.

Population ecology of hantavirus rodent hosts in southern Brazil

In this study we analyze population dynamics of hantavirus rodent hosts and prevalence of infection over a 2-year period in Southern Brazil, a region with a high incidence of hantavirus pulmonary syndrome. The 14 small mammal species captured were composed of 10 rodents and four marsupials, the six most abundant species being Akodon serrensis, Oxymycterus judex, Akodon montensis, Akodon paranaensis, Oligoryzomys nigripes, and Thaptomys nigrita. These species displayed a similar pattern with increasing population sizes in fall/winter caused by recruitment and both, increase in reproductive activity and higher hantavirus prevalence in spring/summer. Specific associations between A. montensis/Jaborá Virus (JABV) and O. nigripes/Juquitiba-like Virus (JUQV-like) and spillover infections between A. paranaensis/JABV, A. serrensis/JABV, and A. paranaensis/JUQV-like were observed. Spillover infection in secondary hosts seems to play an important role in maintaining JABV and JUQV-like in the hantavirus sylvatic cycle mainly during periods of low prevalence in primary hosts.

Serological evidence of hantavirus infection in rural and urban regions in the state of Amazonas, Brazil

Hantavirus disease is caused by the hantavirus, which is an RNA virus belonging to the family Bunyaviridae. Hantavirus disease is an anthropozoonotic infection transmitted through the inhalation of aerosols from the excreta of hantavirus-infected rodents. In the county of Itacoatiara in the state of Amazonas (AM), Brazil, the first human cases of hantavirus pulmonary and cardiovascular syndrome were described in July 2004. These first cases were followed by two fatal cases, one in the municipality of Maués in 2005 and another in Itacoatiara in 2007. In this study, we investigated the antibody levels to hantavirus in a population of 1,731 individuals from four different counties of AM. Sera were tested by IgG/IgM- enzyme-linked immune-sorbent assay using a recombinant nucleocapsid protein of the Araraquara hantavirus as an antigen. Ten sera were IgG positive to hantavirus (0.6%). Among the positive sera, 0.8% (1/122), 0.4% (1/256), 0.2% (1/556) and 0.9% (7/797) were from Atalaia do Norte, Careiro Castanho, Itacoatiara and Lábrea, respectively. None of the sera in this survey were IgM-positive. Because these counties are distributed in different areas of AM, we can assume that infected individuals are found throughout the entire state, which suggests that hantavirus disease could be a local emerging health problem.

A retrospective serologic survey of hantavirus infections in the county of Cássia dos Coqueiros, State of São Paulo, Brazil

INTRODUCTION

In recent years, hantavirus infections producing severe diseases have obtained an increased attention from public health authorities from the countries of Eurasia to the Americas. Brazil has reported 1,300 cases of hantavirus cardiopulmonary syndrome (HCPS) from 1993 to 2010, with about 80 of them occurring in the northeast of the State of São Paulo, with 48% fatality rate. Araraquara virus was the causative agent of HCPS in the region. Considering that hantaviruses causing human disease in the Americas were unknown until 1993, we have looked for hantavirus infections in the population of Cássia dos Coqueiros county, northeast of the State of São Paulo, Brazil, before this time. This county has about 2,800 inhabitants and an economy based on agriculture, including cultivation of Brachiaria decumbens grass. The grass seeds are an important rodent attraction, facilitating transmission of hantavirus to man. Four HCPS cases were reported so far in the county.

METHODS

In this study, 1,876 sera collected from 1987 to 1990 were tested for IgG to hantavirus by IgG-ELISA, using the N recombinant protein of Araraquara virus as antigen.

RESULTS

Positive results were observed in 89 (4.7%) samples, which were all collected in 1987. The positivity among urban inhabitants was 5.3%, compared with 4.3% among those living in rural areas.

CONCLUSIONS

Our results showed that hantavirus infections occurred in Cássia dos Coqueiros, completely unrecognized, even before hantaviruses were described in the Americas.