Hantavirus pulmonary syndrome in Brazil: clinical aspects of three new cases

Hantavirus pulmonary syndrome (HPS) has been recognized recently in Brazil, where 28 cases have been reported as of September 1999. We report here the clinical and laboratory findings of three cases whose diagnoses were confirmed serologically. All the patients were adults who presented a febrile illness with respiratory symptoms that progressed to respiratory failure that required artificial ventilation in two of them. Laboratory findings were most of the time consistent with those reported in the United States in patients infected with the Sin Nombre virus, and included elevated hematocrit and thrombocytopenia; presence of atypical lymphocytes was observed in one patient. The chest radiological findings observed in all the patients were bilateral, diffuse, reticulonodular infiltrates. Two patients died. Histopathological examination of the lungs of these patients revealed interstitial and alveolar edema, alveolar hemorrhage, and mild interstitial pneumonia characterized by infiltrate of immunoblasts and mononuclear cells. In the epidemiologic investigation of one of the cases, serologic (ELISA) tests were positive in 3 (25%) out of 12 individuals who shared the same environmental exposure. HPS should be included in the differential diagnosis of interstitial pneumonia progressing to acute respiratory failure.

Outbreaks of human-herpes virus 6 (HHV-6) infection in day-care centers in Belém, Pará, Brazil

A total of 730 children aged less than 7 years, attending 8 day-care centers (DCCs) in Belém, Brazil were followed-up from January to December 1997 to investigate the occurrence of human-herpes virus 6 (HHV-6) infection in these institutional settings. Between October and December 1997 there have been outbreaks of a febrile- and -exanthematous disease, affecting at least 15-20% of children in each of the DCCs. Both serum- and- plasma samples were obtained from 401 (55%) of the 730 participating children for the detection of HHV-6 antibodies by enzyme-linked immunosorbent assay (ELISA), and viral DNA amplification through the nested-PCR. Recent HHV-6 infection was diagnosed in 63.8% (256/401) of them, as defined by the presence of both IgM and IgG-specific antibodies (IgM+/IgG+); of these, 114 (44.5%) were symptomatic and 142 (55.5%) had no symptoms (p = 0.03). A subgroup of 123 (30.7%) children were found to be IgM-/IgG+, whereas the remaining 22 (5.5%) children had neither IgM nor IgG HHV-6- antibodies (IgM-/IgG-). Of the 118 children reacting strongly IgM-positive ( > or = 30 PANBIO units), 26 (22.0%) were found to harbour the HHV-6 DNA, as demonstrated by nested-PCR. Taken the ELISA-IgM- and- nested PCR-positive results together, HHV-6 infection was shown to have occurred in 5 of the 8 DCCs under follow-up. Serological evidence of recent infections by Epstein-Barr virus (EBV) and parvovirus B19 were identified in 2.0% (8/401) and 1.5% (6/401) of the children, respectively. Our data provide strong evidence that HHV-6 is a common cause of outbreaks of febrile/exanthematous diseases among children attending DCCs in the Belém area.

Infective endocarditis (IE) first diagnosed at autopsy: analysis of 31 cases in Ribeirão Preto, Brazil

Thirty one infective endocarditis (IE) fatal cases whose diagnosis was first obtained at autopsy were studied. The clinical data of these patients (Group 1) showed significant differences compared to other 141 IE cases (Group 2). The average age of 53 years in Group 1 patients was 18 years higher than that of Group 2. The Group 1 patients had a low frequency of IE predisposing heart disease. Both patient groups presented fever (about 87%), but a significant low frequency of cardiac murmur (25.8%) was observed in Group 1 patients and echocardiography tests were performed in only 16.1%, suggesting that IE diagnosis was not suspected. Likewise, although most Group 1 patients appeared with severe acute illness, they did not present the classic IE clinical presentation. Blood cultures were performed in only 64.5% of the Group 1 patients. However, bacteria were isolated in 70% of these blood cultures and Staphylococcus aureus was isolated in 71.4%. The bacteria attacked mitral and aortic valves. Complications such as embolizations and cardiac failure occurred in almost half of the cases and they also presented with infections of the lungs, urinary tract, and central nervous system. Medical procedures were performed in practically all fatal cases whose diagnosis was first obtained at autopsy. Sepsis occurred in about half of the patients and it was followed by shock in more than 25%. This form of IE must be suspected in mature and in old febrile hospitalized patients having infection predisposing diseases, embolization, and suffering medical procedures.

Evidence of active herpesvirus 6 (variant-A) infection in patients with lymphadenopathy in Belém, Pará, Brazil

A total of 323 patients with lymphadenopathy were selected in Belém, Brazil, between January 1996 and December 2001, and screened for the presence of human herpesvirus-6 (HHV-6) IgM- and- IgG antibodies by enzyme-linked immunosorbent assay (ELISA). When seroprevalence is analyzed by gender, similar rates are found for female (60.6%) and male (55.7%) individuals. Seventy-seven (23.8%) patients were HHV-6-IgM-and- IgG-positive (IgM+ subgroup), with positivity rates of 29.7% and 17.7% (p = 0.0007) for female- and male individuals, respectively. Sera from a subgroup (n = 120) of these subjects, with high HHV-6 antibody levels (either IgM+ or IgG+ reactivities), were subsequently processed for the presence of HHV-6 DNA by polymerase chain reaction (PCR)/nested PCR. Active infections (IgM+ and/or IgG+ high levels specific antibodies plus detection of viral DNA) were diagnosed in 20/77 (20.0%) and 8/43 (18.6%); subgroup of the 120 individuals suspected of having HHV-6 suggestive recent infection. All (n = 28) cases of active infection were found to be associated with HHV-6 variant-A (HHV-6A), as detectable by PCR/nested PCR, using variant-specific primer that amplify regions of 195 base pairs (bp) (HHV-6A) and 423 bp (HHV-6B). Rates of HHV-6 DNA detection between female and male patients were similar (p > 0.05) in the IgM+ and IgG+ groups: 20.4% versus 35.7% and 25.0% versus 13.0%, respectively. HHV-6 DNA was detected across < 5 through 41-50-year age-groups for patients whose serum samples were IgM+, with rates ranging from 7.7% (female subjects aged < 5 years) to 80.0% (male, 11-20 years). Among patients whose serological status was IgG+, HHV-6 DNA was detected in < 5, 6-10, 21-30 and > 50 age-groups at rates that ranged from 15.4% (male, < 5 years of age) to 100.0% (female aged 11-20 years). Swelling cervical lymph nodes were the most common sign, accounting for 9 (32.0%) cases in each gender group. Among patients (n = 28) with active infection by HHV-6A variant, duration of symptoms lasted 1-5 days in 35.7% of subjects, whereas in 64.3% of them the disease lasted 6-20 days. Our data suggest that it is worth seeking for HHV-6 infection whenever a patient (infant or adult) presents with lymphadenopathy as a prominent symptom in the course of an acute febrile illness.

Paracoccidioidomycosis in children: clinical presentation, follow-up and outcome

From February, 1981 to May, 2001, 63 children under 15 y old (ages 2 - 15 y, median = 8 y, mean ± 1 SD = 8 ± 3 y) presenting 70 episodes of Paracoccidioidomycosis were admitted. The main clinical manifestations and laboratory features observed upon admission were: lymph node enlargement (87.1%), fever (75.7%), weakness (48.6%), pallor (41.4%), hepatomegaly (40%), splenomegaly (35.7%), anemia (90%), hypergammaglobulinemia (88.5%), eosinophilia (75.5%) and hypoalbuminemia (72.5%). Moderate to severe malnutrition was detected in 35.7% of the episodes (Gomez's criterion). Radiographic and technetium studies showed bone lesions in 20 of the episodes, most of them being multiple lytic lesions, involving both long (70%) and plain bones (30%). First line treatment consisted of an association of sulfametoxazole-trimethoprin, which was used, exclusively, in 50 episodes. Follow-up of hemoglobin levels, number of eosinophils in the peripheral blood, albumin and gammaglobulin serum levels revealed significant sequential improvement one and six months after hospital admission, being quite useful to evaluate treatment effectiveness. Six patients died (9.3%) and four developed sequelae (6.3%) . In conclusion, the juvenile and disseminated forms can be observed in about 70% of the episodes of PCM occurring in children younger than 15 y old, most of them presenting with a febrile lymphoproliferative syndrome associated to anemia, eosinophilia and hypergammaglobulinemia.

Murine (endemic) typhus in Brazil: case report and review

Murine typhus has been increasingly recognized worldwide and is becoming a relevant differential diagnosis in febrile conditions. In Brazil, murine typhus has never received much attention. We present a recently diagnosed case and a literature review that suggests that the disease could be more prevalent in Southeastern Brazil than acknowledged until now.

St. Louis encephalitis vírus: first isolation from a human in São Paulo state, Brasil

This paper reports the isolation of St. Louis encephalitis virus (SLEV) from a febrile human case suspected to be dengue, in São Pedro, São Paulo State. A MAC-ELISA done on the patient's acute and convalescent sera was inconclusive and hemagglutination inhibition test detected IgG antibody for flaviviruses. An indirect immunofluorescent assay done on the C6/36 cell culture inoculated with the acute serum was positive for flaviviruses but negative when tested with dengue monoclonal antibodies. RNA extracted from the infected cell culture supernatant was amplified by RT-PCR in the presence of NS5 universal flavivirus primers and directly sequenced. Results of BLAST search indicated that this sequence shares 93% nucleotide similarity with the sequence of SLEV (strain-MSI.7), confirmed by RT-PCR performed with SLEV specific primers. Since SLEV was identified as the cause of human disease, it is necessary to improve surveillance in order to achieve early detection of this agent in the state of São Paulo and in Brazil. This finding is also an alert to health professionals about the need for more complete clinical and epidemiological investigations of febrile illnesses as in the reported case. SLEV infections can be unrecognized or confused with other ones caused by an arbovirus, such as dengue.

Questing one Brazilian query: reporting 16 cases of Q fever from Minas Gerais, Brazil

Q fever has been considered non-existing in Brazil where reports of clinical cases still cannot be found. This case-series of 16 patients is a result of a systematic search for such illness by means of clinical and serologic criteria. Serologic testing was performed by the indirect microimmunofluorescence technique using phase I/II C. burnetii antigens. Influenza-like syndrome was the most frequent clinical form (eight cases - 50%), followed by pneumonia, FUO (fever of unknown origin), mono-like syndrome (two cases - 12.5% each), lymphadenitis (one case - 6.3%) and spondylodiscitis associated with osteomyelitis (one case - 6.3%). The ages varied from four to 67 years old with a median of 43.5. All but one patient had positive serologic tests for phase II IgG whether or not associated with IgM positivity compatible with acute infection. One patient had both phase I and phase II IgG antibodies compatible with chronic Q fever. Seroconvertion was detected in 10 patients. Despite the known limitations of serologic diagnosis, the cases here reported should encourage Brazilian doctors to include Q fever as an indigenous cause of febrile illness.

Mayaro virus: imported cases of human infection in São Paulo State, Brazil

Mayaro virus (MAYV) is an arbovirus (Togaviridae: Alphavirus) enzootic in tropical South America and maintained in a sylvan cycle involving wild vertebrates and Haemagogus mosquitoes. MAYV cases occur sporadically in persons with a history of recent activities inside or around forests. This paper reports three cases of MAYV fever detected in men infected in Camapuã, MS, Brazil. Serum samples collected at four days and two months after the onset of the symptoms and examined by hemagglutination inhibition test, revealed monotypic seroconversion to MAYV. Isolation of the virus was obtained from one of the samples by inoculation of the first blood samples into newborn mice. A suspension of the infected mouse brain was inoculated into C6/36 cells culture and the virus was identified by indirect immunofluorescent assay with alphavirus polyclonal antibodies. RT-PCR, performed with RNA extracted from the supernatant of C6/36 infected cells in the presence of alphavirus generic primers as well as specific MAYV primers, confirmed these results. The reported cases illustrate the importance of laboratory confirmation in establishing a correct diagnosis. Clinical symptoms are not always indicative of a disease caused by an arbovirus. Also MAYV causes febrile illness, which may be mistaken for dengue.

Cytokine and nitric oxide production by mouse macrophages infected with brazilian flaviviruses

The Flaviviridae family, Flavivirus genus includes viruses that are transmitted to vertebrates by infected mosquitoes or ticks. The genus Flavivirus includes a variety of viruses that cause diseases such as acute febrile illness, encephalitis, and hemorrhagic fever. Flaviviruses primarily infect blood monocytes and tissue macrophages, which have been shown to be permissive, supporting viral replication and serving as virus reservoirs. On the other hand, these cells may have an important antiviral activity related to modulation by cytokine production and by the capacity of these cells to synthesize reactive free radicals such as nitric oxide (NO) which can have a microbicidal effect. The present study was performed in order to determine the production of cytokines interleukin-1beta (IL-1β), tumor necrosis factor -alpha (TNF-α), transforming growth factor- beta (TGF-β) and interferon -alpha (IFN-α) and NO by macrophages infected with one of four Brazilian flaviviruses, Bussuquara virus (BUSV), Yellow Fever virus (YFV), Rocio virus (ROCV) and Encephalitis Saint Louis virus (SLEV), and to verify the possible antiviral effect of NO during macrophage infection with ROCV. Moreover, we asked if the different viruses were able to regulate bacterial lipopolysaccharide (LPS) induced cytokine production. Our results showed that YFV and SLEV reduced the production of IL-1β and TGF-β by LPS-stimulated macrophages, while ROCV only diminished LPS-stimulated TGF-β synthesis. On the other hand, BUSV more likely favored an enhancement of the LPS-induced production of IL-1β by macrophages. Additionally, while most of the viruses stimulated the production of IFN-α, none of them altered the production of TNF-α by murine macrophages. Interestingly, all viruses induced synthesis of NO that was not correlated with antiviral activity for ROCV.

SAINT LOUIS ENCEPHALITIS VIRUS IN MATO GROSSO, CENTRAL-WESTERN BRAZIL

The dengue virus (DENV), which is frequently involved in large epidemics, and the yellow fever virus (YFV), which is responsible for sporadic sylvatic outbreaks, are considered the most important flaviviruses circulating in Brazil. Because of that, laboratorial diagnosis of acute undifferentiated febrile illness during epidemic periods is frequently directed towards these viruses, which may eventually hinder the detection of other circulating flaviviruses, including the Saint Louis encephalitis virus (SLEV), which is widely dispersed across the Americas. The aim of this study was to conduct a molecular investigation of 11 flaviviruses using 604 serum samples obtained from patients during a large dengue fever outbreak in the state of Mato Grosso (MT) between 2011 and 2012. Simultaneously, 3,433 female Culex spp. collected with Nasci aspirators in the city of Cuiabá, MT, in 2013, and allocated to 409 pools containing 1-10 mosquitoes, were also tested by multiplex semi-nested reverse transcription PCR for the same flaviviruses. SLEV was detected in three patients co-infected with DENV-4 from the cities of Cuiabá and Várzea Grande. One of them was a triple co-infection with DENV-1. None of them mentioned recent travel or access to sylvatic/rural regions, indicating that transmission might have occurred within the metropolitan area. Regarding mosquito samples, one pool containing one Culex quinquefasciatus female was positive for SLEV, with a minimum infection rate (MIR) of 0.29 per 1000 specimens of this species. Phylogenetic analysis indicates both human and mosquito SLEV cluster, with isolates from genotype V-A obtained from animals in the Amazon region, in the state of Pará. This is the first report of SLEV molecular identification in MT.

SERUM LEVELS OF COPPER AND IRON IN DENGUE FEVER

SUMMARY The role of trace elements in dengue virulence is not yet known. The present study assessed the serum levels of two micronutrients, copper and iron, in cases of dengue fever. The study involved 96 patients of whom 48 had either severe or non-severe forms of dengue (with and without warning signs), and the remaining 48 were patients with other febrile illnesses (OFI), used as controls. Serum levels of copper and iron were evaluated at admission and by the time of defervescence using commercially available kits. At admission, no difference in the level of serum copper was observed between cases and controls. In the group of dengue cases, the copper level was found to be significantly decreased in severe and non-severe cases with warning signs, compared to non-severe cases without warning signs. In contrast, by the time of defervescence the copper level was found to be increased in all dengue cases compared to OFI controls, but no difference was observed among dengue cases. Unlike OFI controls, dengue cases showed an increasing pattern of copper levels from admission until defervescence. On the other hand, no such significant differences were observed in the serum level of iron in the clinical groups, except for a decreased iron level found in severe cases, compared to non-severe dengue without warning signs. The results show that copper is associated with dengue severity and this finding emphasizes the need to investigate the involvement of trace elements in disease severity so as to improve the prognosis of dengue.

FIRST REPORT OF ACUTE CHAGAS DISEASE BY VECTOR TRANSMISSION IN RIO DE JANEIRO STATE, BRAZIL

SUMMARY Chagas disease (CD) is an endemic anthropozoonosis from Latin America of which the main means of transmission is the contact of skin lesions or mucosa with the feces of triatomine bugs infected by Trypanosoma cruzi. In this article, we describe the first acute CD case acquired by vector transmission in the Rio de Janeiro State and confirmed by parasitological, serological and PCR tests. The patient presented acute cardiomyopathy and pericardial effusion without cardiac tamponade. Together with fever and malaise, a 3 cm wide erythematous, non-pruritic, papule compatible with a "chagoma" was found on his left wrist. This case report draws attention to the possible transmission of CD by non-domiciled native vectors in non-endemic areas. Therefore, acute CD should be included in the diagnostic workout of febrile diseases and acute myopericarditis in Rio de Janeiro.

A NEW POSSIBILITY FOR SURVEILLANCE: DO WE IDENTIFY ALL CASES OF LEPTOSPIROSIS?

SUMMARY Leptospirosis is a febrile disease with a typically underestimated global incidence, especially in regions where dengue is endemic. Therefore, it is difficult to accurately determine the number of leptospirosis cases in these areas, which contributes to significant under-reporting this disease. In this study, we estimated the number of possible leptospirosis cases among dengue-like cases that were reported during 2008, 2010, and 2012 in the city of Fortaleza, northeast Brazil. Patients were evaluated for dengue and leptospirosis using immunoenzymatic tests for IgM antibodies that were specific to each pathogen. Among the suspected cases of dengue that resulted as negative in laboratory tests, 10.8% (2008), 19.2% (2010), and 30.8% (2012) were confirmed to be leptospirosis. Considering the cases reported by the surveillance authority as dengue that were subsequently discarded based on the laboratory test results, we estimate that the number of actual leptospirosis cases may be 26 to 49 times higher than those diagnosed and reported by the Health Services. Furthermore, we believe that approximately 20% of dengue-like cases may be leptospirosis cases in areas where the two diseases are endemic.

DENGUE OUTBREAK IN MATO GROSSO STATE, MIDWESTERN BRAZIL

Dengue virus (DENV) is the most frequent arbovirus worldwide. In this study, we report a large outbreak in Mato Grosso State (MT). Serum samples from 604 patients with acute febrile illness for less than five days were inoculated in C6/36 cells, then infected cells were subjected to an indirect immunofluorescence test for DENV serotypes and yellow fever virus. Serum samples were submitted to a multiplex-semi-nested-RT-PCR for 11 flaviviruses. DENV-4 was isolated in 150/604 (24.8%) and DENV-1 in 19/604 (3.1%) specimens. By RT-PCR, 331 (54.8%) samples tested positive for DENV; 321 had single infections (DENV-4 n = 305; DENV-1 n = 15; DENV-3 n = 1), nine had co-infections of DENV-1/DENV-4, and one of DENV-2/DENV-4. DENV-4 was detected in 315/331 (95.2%) positive patients from 17 municipalities, and DENV-1 in 24/331 (7.2%) patients from five cities in north-central MT and the city of Cuiaba. The incidence of infection was higher in patients aged 20-39 (142/331; 42.9%). The NS5 partial nucleotide sequence of DENV-1 was most similar to that of genotype V, DENV-2 to Southeast Asian/American, DENV-3 to genotype III, and DENV-4 to genotype II strains, considered the most frequent strains in Brazil. This outbreak coincided with the introduction of DENV-4 in the state. Cuiaba was hyperendemic for the four DENV serotypes, highlighting the necessity for arbovirus surveillance in MT.