Gelse Mazzoni Campos

Role of mixed Th1 and Th2 serum cytokines on pathogenesis and prognosis of hantavirus pulmonary syndrome

The hantavirus pulmonary syndrome (HPS) is an emerging syndrome in the Americas. The disease results from intense immune activation and changes in vascular permeability. The aim of this study was to determine the profile of serum cytokines in HPS patients looking for correlation with the clinical parameters, severity and outcome of illness. Studying 21 HPS patients, we found that IL-6 may have an important role in the pathogenesis of HPS, being associated with fatal outcome. Our results also support a mixed Th1/Th2 immune response during the course of HPS and that the magnitude of Th1 response effector cytokines is correlated to HPS severity. The decreased levels of TGF-beta observed in HPS patients suggest that immunoregulatory activity could be damaged in these patients.

Síndrome pulmonar e cardiovascular por Hantavirus: aspectos epidemiológicos, clínicos, do diagnóstico laboratorial e do tratamento

The Hantavirus pulmonary and cardiovascular syndrome (HPCVS) is an emerging disease in Brazil. In this study, eight confirmed cases of HPCVS were studied. All the patients presented fever and dyspnea as well as thrombocytopenia and hypoxemia. Tachycardia, malaise, hypotension and lung rales occurred in 75 to 87.5% of the cases. Hemoconcentration, blood cell count increased and immature neutrophils, and high levels of creatinine were observed in 75 to 87.5%. Intravenous liquid infusion, the use of drugs for increasing systemic vascular resistance and inotropism, and mechanic ventilation were used for the patients. Mechanical ventilation and volume administration should be started precociously, preferable in intensive care units employing recommended universal and respiratory precautions. Careful volume administration should be limited if signs of pulmonary edema develop. Mortality (50%) is high and probably related to the severity of the disease as well as to a delayed attending of the patients for intensive management. It is important to report hantaviruses and HPCVS to the Brazilian medical community considering that many cases could be undiagnosed.The Hantavirus pulmonary and cardiovascular syndrome (HPCVS) is an emerging disease in Brazil. In this study, eight confirmed cases of HPCVS were studied. All the patients presented fever and dyspnea as well as thrombocytopenia and hypoxemia. Tachycardia, malaise, hypotension and lung rales occurred in 75 to 87.5% of the cases. Hemoconcentration, blood cell count increased and immature neutrophils, and high levels of creatinine were observed in 75 to 87.5%. Intravenous liquid infusion, the use of drugs for increasing systemic vascular resistance and inotropism, and mechanic ventilation were used for the patients. Mechanical ventilation and volume administration should be started precociously, preferable in intensive care units employing recommended universal and respiratory precautions. Careful volume administration should be limited if signs of pulmonary edema develop. Mortality (50%) is high and probably related to the severity of the disease as well as to a delayed attending of the patients for intensive management. It is important to report hantaviruses and HPCVS to the Brazilian medical community considering that many cases could be undiagnosed.

Hantaviruses in São Paulo State, Brazil.

To the Editor: Hantavirus pulmonary syndrome (HPS) is an emerging health problem in Brazil. This syndrome was first reported in 1993 in three persons living in a rural area of Juquitiba County; two of them died of acute respiratory failure (1). Although Juquitiba County is part of the metropolitan area of greater Sao Paulo City, patients lived in a recently deforested region. From 1993 through 2002, approximately 200 HPS cases were reported in Brazil, with a 40% case-fatality ratio (Ministry of Health of Brazil, Report on Hantavirus cases 1993–2002, unpub. data). The wild rodent Bolomys laziurus is believed to be the most important hantavirus reservoir in the State of Sao Paulo, based on high levels of specific antibodies observed in serum from captured specimens (L.E. Pereira, Adolpho Lutz Institute, pers. comm., 2001). The economy of the inland region of Ribeirao Preto in the State of Sao Paulo, with its 3.5 million inhabitants, is based on the sugar cane agroindustry. The region has been almost completely deforested, with important consequences to the environment and wild rodent ecology. Twenty HPS cases were reported in Ribeirao Preto in the last 5 years, with a 60% case-fatality ratio. Review of medical records showed that a prodromic fever occurred in all 14 case-patients studied; dyspnea, cough, hypotension, and tachycardia occurred in about two thirds of patients; and hemorrhagic phenomena (hematuria, melena, and hypermenorrhea) in about one third. Thrombocytopenia was observed in all the patients, elevated hematocrit in about three fourths, and leukocytosis with neutrophilia and a left shift in the differential count in about two thirds. Serum creatinine levels were also increased (average level 2 mg/dL). Chest radiographs showed diffuse alveolar flocculant infiltrates in most cases (2,3). Laboratory diagnosis of HPS was made by serologic testing (enzyme-linked immunosorbent assay [ELISA]) in 18 cases and by reverse transcription–polymerase chain reaction (RT-PCR) in 11 cases; for 7 cases, both techniques were used. We performed a nucleotide sequence analysis of the N gene of hantavirus (residues 236–477) obtained from the blood of 11 of the 20 patients. This analysis showed that the infections were caused by Araraquara virus, a previously known hantavirus that had been detected by RT-PCR in the serum of an HPS patient living in a nearby county (4). Thus, Araraquara virus is the causative agent of a severe form of HPS, with a high death rate. This high death rate could also be related to the lack of adequate initial therapy provided by clinicians who probably did not immediately suspect HPS and may have not recommended hospitalization in intensive-care units. In addition, some hospitalized patients were in shock when first seen and were rehydrated with massive quantities of fluids, which may have aggravated pulmonary edema and contributed to death. The occurrence of 10% of the Brazilian HPS reported cases in Ribeirao Preto indicates that this region is suitable for studying the epidemiology of hantavirus infections. A serologic survey conducted in the region in 1999, which included 567 primary-care patients from Ribeirao Preto, Guariba, and Jardinopolis Counties, found that 7 (1.23%) of them had immunoglobulin (Ig) G antibodies to Sin Nombre virus by ELISA and that 5 of those lived in Jardinopolis (population 30,000), a county where a fatal case of HPS occurred in 1999 (5). Thus, Jardinopolis County was chosen for a population-based survey. In May 2001, we obtained personal information and collected fingerprick blood samples from 818 participants, 15–70 years of age, living in urban and rural areas of the county. IgG antibodies to the N recombinant protein of Andes virus were detected by ELISA in the blood samples of 14.3% of the participants (5). Even though all HPS cases in Ribeirao Preto were associated with rural activity and rodent exposure, these serologic data suggest that hantavirus infections are common in Jardinopolis County, independent of sex, profession, or history of contact with rodents. None of the 14.3% participants with IgG antibodies to hantavirus had a history of HPS-like disease, and the ELISA test showed cross-reactions with most of the South American hantaviruses, including Araraquara. Persons living in the urban area had higher levels of antibodies to hantavirus than those from rural areas. In Ribeirao Preto, the physical boundaries of cities have expanded to incorporate other areas, encroaching upon rural areas with many popular subsidized housing complexes. Work-related and recreational rural activities in that region are also frequent, which makes it difficult to interpret these data. These results suggest that in this region of southeast Brazil, hantaviruses may be causing undiagnosed asymptomatic or clinically minor infections in addition to typical HPS. This finding envokes important questions. Is more than one hantavirus circulating in this region, causing mostly benign infections? Is Araraquara virus widespread, causing mostly inapparent infections and only rarely causing HPS? Would HPS be associated with some predisposing condition in the infected person? If more than one hantavirus is circulating in the region, could urban rodents be reservoirs? Further studies are necessary to better understand the epidemiology and clinical signs and symptoms of hantavirus infection in the region of Ribeirao Preto. Such studies should emphasize determining the reservoirs, the modes of virus transmission to people, and the possible distinct clinical forms of hantavirus infections.

Síndrome pulmonar e cardiovascular por hantavírus: aspectos clínicos de uma doença emergente no sudeste brasileiro

Pulmonary and cardiovascular syndrome due to hantavirus is a disease caused by inhalation of aerosols from the excreta of wild rodents contaminated by viruses of the Bunyaviridae family. We studied the clinical and laboratory manifestations of 70 cases that occurred in the region of Ribeirão Preto, SP, Brazil, between 1998 and 2007. The frequency of symptoms was as follows: dyspnea (87%), fever (81%), coughing (44%), headache (34%), tachycardia (81%), low arterial blood pressure (56%), metabolic acidosis (57%), lymphocytopenia (51%), hematocrit > 45% (70%), leukocytosis with left deviation (67%), creatinine (51%) and urea (42%). Mortality (54.3%) occurred mainly on the fourth day. Respiratory insufficiency, low arterial blood pressure and shock occurred after 24 to 48 hours. High hematocrit and decreased platelet levels were signs strongly suggestive of the disease. The diagnostic hypothesis of atypical pneumonia was associated with a good prognosis (p = 0.0136). Fluid infusion greater than 2,000 ml and arterial hypotension were associated with a poor prognosis (p = 0.0286 and p = 0.0453).

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

INTRODUCTION Hantavirus pulmonary and cardiovascular syndrome (HPCS) is an emerging serious disease in the Americas. Hantaviruses (Bunyaviridae) are the causative agents of this syndrome and are mainly transmitted through inhalation of aerosols containing the excreta of wild rodents. In the Ribeirão Preto region (state of São Paulo, Brazil), HPCS has been reported since 1998, caused by the Araraquara virus (ARAV), for which Necromys lasiurus is the rodent reservoir. This study aimed to show diagnostic results relating to infection in humans and rodents, obtained at the Virology Research Center of the Ribeirão Preto School of Medicine, University of São Paulo, between 2005 and 2008. METHODS HPCS was diagnosed by means of ELISA and/or RT-PCR in 11 (21.2%) out of 52 suspected cases, and 54.4% of these were fatal. Furthermore, 595 wild rodents (Necromys lasiurus, Akodon sp, Calomys tener and Oligoryzomys sp) were caught between 2005 and 2008. RESULTS Fifteen (2.5%) of these rodents presented antibodies for hantavirus, as follows: Necromys lasiurus (4%), Calomys tener (1.9%) and Akodon sp (1.5%). Nucleotide sequences obtained through RT-PCR from one HPCS patient and one Calomys tener rodent were compared with hantavirus sequences from GenBank, which showed that both were homologous with ARAV. CONCLUSIONS This work corroborates previous studies showing that ARAV is the hantavirus causing HPCS in the Ribeirão Preto region. It also shows that rodents infected with hantavirus represent a constant risk of transmission of this virus to man.

Association of −308G/A polymorphism in the tumor necrosis factor-α gene promoter with susceptibility to development of hantavirus cardiopulmonary syndrome in the Ribeirão Preto region, Brazil

Activation of the immune response in hantavirus cardiopulmonary syndrome (HCPS) leads to a high TNF production, probably contributing to the disease. The polymorphic TNF2 allele (TNF −308G/A) has been associated with increased cytokine production. We investigated the association of the TNF2 allele with the outcome of hantavirus infection in Brazilian patients. A total of 122 hantavirus-exposed individuals (26 presenting HCPS and 96 only hantavirus seroconversion) were studied. The TNF2 allele was more frequently found in HCPS patients than in individuals with positive serology for hantavirus but without a history of HCPS illness, suggesting that the TNF2 allele could represent a risk factor for developing HCPS.

Natural Host Relationships and Genetic Diversity of Rodent-Associated Hantaviruses in Southeastern Brazil

Objective: Hantaviruses are rodent-borne RNA viruses that have caused hantavirus cardiopulmonary syndrome in several Brazilian regions. In the present study, geographical distribution, seroprevalence, natural host range, and phylogenetic relations of rodent-associated hantaviruses collected from seven counties of Southeastern Brazil were evaluated. Methods: ELISA, RT-PCR and phylogenetic analysis were used in this study. Results: Antibodies to hantavirus were detected in Bolomys lasiurus, Akodon sp. and Oligoryzomys sp., performing an overall seroprevalence of 5.17%. All seropositive rodents were associated with grasslands or woods surrounded by sugar cane fields. Phylogenetic analysis of partial S- and M-segment sequences showed that viral sequences isolated from B. lasiurus specimens clustered with Araraquara virus. However, a sequence from Akodon sp. shared 100% similarity with Argentinian/Chilean viruses based on the partial S-segment amino acid sequence. Conclusion: These results indicate that there are associations between rodent reservoirs and hantaviruses in some regions of Southeastern Brazil, and suggest the existence of additional hantavirus genetic diversity and host ecology in these areas.

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.

Clinical and laboratory findings related to a favorable evolution of hantavirus pulmonary syndrome

The medical records of 27 patients with hantavirus pulmonary syndrome were analyzed according to the need for invasive mechanical ventilation in relation to the following data up on hospital admission: age, gender, fever, cough, dyspnea, systolic arterial blood pressure, heart rate, levels of hemoglobin, hematocrit, leukocytes, lymphocytes, platelets, creatinine and arterial blood gases. The volume infused during the first 24 hours after admission, the use of inotropic agents, the use of corticosteroids and the patient outcomes were also evaluated. A favorable outcome was related to systolic blood pressure(3) 100 mmHg, heart rate lower than 100 beats per minute, creatinine below 1.6 mg/dl, arterial blood pH(3) 7.35, bicarbonate higher than 15 mEq/dl, oxygen saturation higher than 84.1%, lower rehydration volume in the first 24 hours of hospitalization and no use of inotropic agents. Absence of clinical and laboratory signs of circulatory shock up on admission was associated with a favorable outcome of the patients.

Polymorphisms in Human Leukocyte Antigens, Human Platelet Antigens, and Cytokine Genes in Hantavirus Cardiopulmonary Syndrome Patients from Ribeirao Preto, Brazil

Hantavirus cardiopulmonary syndrome is a severe human disease associated with hantavirus infection. The clinical course of illness varies greatly among individuals, possibly due to viral and immunological elements and the influence of host genetic factors on clinical outcome. As the magnitude of immune activation has been associated with disease severity, polymorphisms in genes involved in the immune response that may affect the development of this syndrome were investigated. Polymorphisms in the TGF‐β, IL‐10, IL‐6, and IFN‐γ genes, human leukocyte antigens (HLA), and human platelet alloantigens (HPA) genes were investigated in 122 patients with Araraquara virus infection from Ribeirão Preto, Brazil. Patients were divided into two groups: hantavirus cardiopulmonary syndrome (HCPS group; n = 26) and hantavirus seropositive only (n = 96). The frequencies of HLA alleles, cytokines and platelet antigen genotypes were evaluated in both groups and compared to a control group. The data demonstrated no significant influence of the HLA alleles, HPA, IL‐6, and IL‐10 genotypes on susceptibility to hantavirus infection. However, the hantavirus seropositive group presented a significantly higher frequency of a polymorphism associated with a high IFN‐γ production than the HCPS group. In addition, a genotype associated with high TGF‐β production was found more frequently in individuals infected with hantavirus than in the control group. This phenotype was associated with a less intense thrombocytopenia in the HCPS group and may be protective against the most severe form of hantavirus disease. More studies are required to quantify further the influence of the high TGF‐β producer phenotype on the outcome of hantavirus infection. J. Med. Virol. 86:1962–1970, 2014.