Surveillance of Arboviruses in Primates and Sloths in the Atlantic Forest, Bahia, Brazil.

From 2006 through 2014, we conducted seroepidemiological surveys on non-human primates and sloths to investigate the possible circulation of arboviruses in Bahia Atlantic Forest, Brazil. We collected a total of 196 samples from 103 Leontopithecus chrysomelas, 7 Sapajus xanthosternos, 22 Bradypus torquatus and 7 Bradypus variegatus. Serum samples were tested using neutralization test and hemagglutination inhibition test to detect total antibodies against 26 different arboviruses. The overall prevalence of arboviruses was 36.6% (51/139), with the genus Flavivirus having the highest prevalence (33.1%; 46/139), followed by Phlebovirus (5.0%; 7/139), Orthobunyavirus (4.3%; 6/139) and Alphavirus (0.7%; 1/139). Monotypic reactions suggest that the wild animals were exposed naturally to at least twelve arboviruses. Added results from the neutralization test, animals were exposed to thirteen arboviruses. Most of these viruses are maintained in transmission cycles independent of human hosts, although antibodies against dengue virus serotypes 1, 2 and 3 were found in this study. To our knowledge, this is the first study reporting exposure to arboviruses in L. chrysomelas, S. xanthosternos and B. torquatus. Our results also highlight that the Southern Bahia Atlantic Forest has a variety of vertebrate hosts and potential vectors, which may support the emergence or re-emergence of arboviruses, including those pathogenic to humans.

Simple feed-forward wide-range frequency offset estimator for optical coherent receivers.

We propose and experimentally demonstrate a hardware-efficient, feed-forward, wide-range frequency offset estimator for DSP-based optical coherent receivers. Using a simple relationship of signal spectrum, this estimator is capable to estimate offsets in a range compliant with OIF requirements. Obtained results show that this estimator has a high tolerance to spectrum asymmetry caused by electrical and optical signal filtering, even when using return-to-zero pulse shaping.

Isolation of yellow fever virus from nulliparous Haemagogus (Haemagogus) janthinomys in eastern Amazonia.

In 1998, an epizootic of yellow fever (YF) killed many howler monkeys (Alouatta spp.) in eastern Amazonia near the city of Altamira. An infection level with YF virus of approximately 3.6% was determined from analysis of 456 females of Haemagogus janthinomys Dyar, the main enzootic YF vector in South America. One month later, a second study of 164 females captured in the same place led to infection levels of 0.8% for parous and 2.9% for nulliparous females. These results lead to the conclusion that vertical transmission, one of the key elements in the epidemiology of YF, occurs in South America as it does in Africa.

Epidemic of jungle yellow fever in Brazil, 2000: implications of climatic alterations in disease spread.

Seventy-seven human cases of sylvatic yellow fever were reported in Brazil during the period January-June 2000. The first cases were reported 1 week after New Year's day and originated at Chapada dos Veadeiros, a tourist canyon site in Goiás state, near Brasília, the Brazilian capital. The laboratory procedures used for diagnoses included serology with an IgM capture assay and plaque reduction neutralization test, virus isolation in suckling mice and C6/36 cells, and immunohistochemistry. All cases were diagnosed by at least two different laboratory procedures, with the exception of the first three fatal cases, which were diagnosed on the basis of clinical and epidemiological information. The cases were reported in eight Brazilian states as follows: Goiás with 64.9% (50 cases); Amazonas (1); Bahia (10); Distrito Federal (1); Mato Grosso (4); Minas Gerais (2); Pará (1); São Paulo (2); and Tocantins (6). Patient ages were within the following ranges: 13-74 years old (mean 34.3), 64 (84.4%) were male, especially agricultural workers (n = 30), but tourists (n = 11), carpenters (n = 4), fishermen (n = 4), students (n = 3), truck drivers (n = 3), and other people (n = 22) were also sickened. The case fatality rate was 50.6% (39/77). In Bahia state, a serologic survey that was carried out has suggested a symptomatic/asymptomatic coefficient of 1:4. Field studies developed in Distrito Federal, Goiás, and São Paulo states showed that Haemagogus janthinomys was the mosquito species associated with the transmission. A single strain was also obtained from Aedes scapularis in Bahia. Epizootic occurrence (monkey mortality) was observed in 49 municipalities mainly in Goiás state, where 40 municipalities made reports, 21 of which also diagnosed human cases. Data obtained by the National Institute of Meteorology in Brazil showed an increase in temperature and rain in December 1999 and the first 3 months of 2000 in Goiás and surrounding states, which perhaps has contributed to the intense and widespread transmission of the yellow fever virus. The relatively small number of cases probably reflects the extensive use of yellow fever 17D-vaccine during the last 3 years, in which about 45 million doses were used. During the last months of 1999, 16 and 11 yellow fever cases were reported in Tocantins and Goiás states, respectively. It is noteworthy that the last reported autochthonous cases of sylvatic yellow fever in São Paulo and Bahia, both states outside the endemic/enzootic area, had occurred in 1953 and 1948, respectively.

Hantavirus pulmonary syndrome in Anajatuba, Maranhão, Brazil.

The authors report a confirmed case of hantavirus pulmonary syndrome in the rural area of the municipality of Anajatuba, state of Maranhão. Two other suspected cases from the same region are also described. The confirmed case involved a previously healthy young woman who died with signs and symptoms of acute respiratory insufficiency 5 days after presenting fever, myalgia and a dry cough. The patient was a student who was helping her parents with work in the fields; it was a habit of the family to store rice inside the house. The suspected cases involved two first-degree relatives working as field hands who died of acute respiratory insufficiency 24 and 48 hours, respectively, after presenting fever, myalgia and a dry cough. Both stored rice and corn inside their home. People living in the region reported massive infestations with rats in the woods and fields.

Yellow fever in Pará State, Amazon region of Brazil, 1998-1999: entomologic and epidemiologic findings.

Yellow fever (YF) is frequently associated with high severity and death rates in the Amazon region of Brazil. During the rainy seasons of 1998 and 1999, 23 (eight deaths) and 34 (eight deaths) human cases of YF were reported, respectively, in different geographic areas of Pará State; most cases were on Marajó Island. Patients were 1 to 46 years of age. Epidemiologic and ecological studies were conducted in Afuá and Breves on Marajó Island; captured insects yielded isolates of 4 and 11 YF strains, respectively, from Haemagogus janthinomys pooled mosquitoes. The cases on Marajó Island in 1999 resulted from lack of vaccination near the focus of the disease and intense migration, which brought many nonimmune people to areas where infected vectors were present. We hypothesize that YF virus remains in an area after an outbreak by vertical transmission among Haemagogus mosquitoes.

Serious adverse events associated with yellow fever 17DD vaccine in Brazil: a report of two cases.

BACKGROUND: The yellow fever vaccine is regarded as one of the safest attenuated virus vaccines, with few side-effects or adverse events. We report the occurrence of two fatal cases of haemorrhagic fever associated with yellow fever 17DD substrain vaccine in Brazil. METHODS: We obtained epidemiological, serological, virological, pathological, immunocytochemical, and molecular biological data on the two cases to determine the cause of the illnesses. FINDINGS: The first case, in a 5-year-old white girl, was characterised by sudden onset of fever accompanied by headache, malaise, and vomiting 3 days after receiving yellow fever and measles-mumps-rubella vaccines. Afterwards she decompensated with icterus and haemorrhagic signs and died after a 5-day illness. The second patient-a 22-year-old black woman-developed a sore throat and fever accompanied by headache, myalgia, nausea, and vomiting 4 days after yellow fever vaccination. She then developed icterus, renal failure, and haemorrhagic diathesis, and died after 6 days of illness. Yellow fever virus was recovered in suckling mice and C6/36 cells from blood in both cases, as well as from fragments of liver, spleen, skin, and heart from the first case and from these and other viscera fragments in case 2. RNA of yellow fever virus was identical to that previously described for 17D genomic sequences. IgM ELISA tests for yellow fever virus were negative in case 1 and positive in case 2; similar tests for dengue, hantaviruses, arenaviruses, Leptospira, and hepatitis viruses A-D were negative. Tissue injuries from both patients were typical of wild-type yellow fever. INTERPRETATION: These serious and hitherto unknown complications of yellow fever vaccination are extremely rare, but the safety of yellow fever 17DD vaccine needs to be reviewed. Host factors, probably idiosyncratic reactions, might have had a substantial contributed to the unexpected outcome.

Inadequate management of natural ecosystem in the Brazilian Amazon region results in the emergence and reemergence of arboviruses.

A total of 187 different species of arboviruses and other viruses in vertebrates were identified at the Evandro Chagas Institute (IEC) from 1954 to 1998, among more than 10,000 arbovirus strains isolated from humans, hematophagous insects, and wild and sentinel vertebrates. Despite intensive studies in the Brazilian Amazon region, especially in Pará State, very little is known about most of these viruses, except for information on date, time, source, and method of isolation, as well as their capacity to infect laboratory animals. This paper reviews ecological and epidemiological data and analyzes the impact of vector and host population changes on various viruses as a result of profound changes in the natural environment. Deforestation, mining, dam and highway construction, human colonization, and urbanization were the main manmade environmental changes associated with the emergence and/or reemergence of relevant arboviruses, including some known pathogens for humans.

Phenotypic and molecular analyses of yellow fever 17DD vaccine viruses associated with serious adverse events in Brazil.

The yellow fever (YF) 17D virus is one of the most successful vaccines developed to data. Its use has been estimated to be over 400 million doses with an excellent record of safety. In the past 3 years, yellow fever vaccination was intensified in Brazil in response to higher risk of urban outbreaks of the disease. Two fatal adverse events temporally associated with YF vaccination were reported. Both cases had features similar to yellow fever disease, including hepatitis and multiorgan failure. Two different lots of YF 17DD virus vaccine were administered to the affected patients and also to hundreds of thousands of other individuals without any other reported serious adverse events. The lots were prepared from the secondary seed, which has been in continuous use since 1984. Nucleotide sequencing revealed minor variations at some nucleotide positions between the secondary seed lot virus and the virus isolates from patients; these differences were not consistent across the isolates, represented differences in the relative amount of each nucleotide in a heterogeneous position, and did not result in amino acid substitutions. Inoculation of rhesus monkeys with the viruses isolated from the two patients by the intracerebral (ic) or intrahepatic (ih) route caused minimal viremia and no clinical signs of infection or alterations in laboratory markers. Central nervous system histological scores of rhesus monkeys inoculated ic were within the expected range, and there were no histopathological lesions in animals inoculated ih. Altogether, these results demonstrated the genetic stability and attenuated phenotype of the viruses that caused fatal illness in the two patients. Therefore, the fatal adverse events experienced by the vaccinees are related to individual, genetically determined host factors that regulate cellular susceptibility to yellow fever virus. Such increased susceptibility, resulting in clinically overt disease expression, appears to be extremely rare.

Dengue epidemic in Belém, Pará, Brazil, 1996-97.

We describe clinical and epidemiologic findings during the first epidemic of dengue fever in Belém, Pará State, Brazil, in 1996-97. Of 40,237 serum samples, 17,440 (43%) were positive for dengue by virus isolation or serologic testing. No hemorrhagic cases or deaths were reported. Mycobacterium tuberculosis

[A seroepidemiological survey on the island of São Luis during a dengue epidemic in Maranhão]. / Inquérito soro-epidemiológico na ilha de São Luis durante epidemia de dengue no Maranhão.

The island of São Luis in the State of Maranhão, constituted by the municipalities of São Luis-SL (835,428 inhabitants), São José de Ribamar-SJR (60,633 inhabitants) and Paço do Lumiar-PL (80,274 inhabitants), has been suffering dengue (DEN) fever epidemics since 1995, caused by DEN-1. In 1996, from August through October, an aleatory sero-epidemiologic survey was carried out in order to estimate the incidence of DEN infection and to analyze other clinical and epidemiological parameters. A questionnaire was applied and serum samples were simultaneously obtained. Serum samples were tested by hemagglutination inhibition (HI). Results were analyzed using Lotus 123, Epi-info 6.0, Excel 5.0 and STATA softwares. A total of 1,217 serum samples were obtained (101 of PL, 100 of SJR and 1017 of SL). The rate of DEN was 55.4% in PL, 28% in SJR and 41.4% in SL, suggesting the occurrence of 401,933 infections. No difference was seen between males and females, but infection occurred more in the upper social class than in poor people (p < 0.003), and was more frequent in adults than in children (p < 0.0004). In SL, the incidence was stratified into seven sanitary districts (SD), and prevalence was found to range from 26.1% in SD4 to 56.8% in SD1 (p < 0.0001). Symptoms were more frequently reported by people whose HI was positive: they included fever, headache, chills, dizziness, retrobulbar pains, muscle and joint pains, nausea, anorexia and skin rash. In spite of the high incidence of infection, no hemorrhagic cases were reported.

[Anti-Hantavirus antibodies in school children in Salvador, Bahia]. / Anticorpos anti-hantavírus em escolares de Salvador, Bahia.

Hantavirosis are emerging diseases in the Americas. Although considered rare in children, among the five cases diagnosed in Brazil, one was in this age group. To know the serum-prevalence of hantavirosis in the pediatric group (schoolchildren) of low social economic level in Salvador, Bahia State, and to associate demographic, socio-economic and environmental factors to the serologic results, a standard questionnaire was applied and blood samples were collected from 379 students of two public schools. Sera were tested by indirect Immunofluorescent Antibody (IFA) IgG for Hantaan Virus (HTN) and Immunoenzymatic test (ELISA) for Sin Nombre viruses. Ages varied from five to seventeen years with a mean age of 10.2 years. The proportion of sera positive to HTN virus was 13.2%, and there were no positive antibodies to SN virus. The frequency of positivity was higher in the older group, similar among sexes and racial groups, and there was no association with the exposure to urban rodents. The antibodies anti-HTN serum-prevalence in low social economic level school children is high and confirm the circulation of hantaviruses in Salvador-Bahia, Brazil; the nonobservation of antibodies anti-SN indicates that the species are other than Sin Nombre Virus.

Anticorpos anti-hantavírus em escolares de Salvador, Bahia / Anti-Hantavirus antibodies in school children in Salvador, Bahia

Hantavirosis are emerging diseases in the Americas. Although considered rare in children, among the five cases diagnosed in Brazil, one was in this age group. To know the serum-prevalence of hantavirosis in the pediatric group (schoolchildren) of low social economic level in Salvador, Bahia State, and to associate demographic, socio-economic and environmental factors to the serologic results, a standard questionnaire was applied and blood samples were collected from 379 students of two public schools. Sera were tested by indirect Immunofluorescent Antibody (IFA) IgG for Hantaan Virus (HTN) and Immunoenzymatic test (ELISA) for Sin Nombre viruses. Ages varied from five to seventeen years with a mean age of 10.2 years. The proportion of sera positive to HTN virus was 13.2%, and there were no positive antibodies to SN virus. The frequency of positivity was higher in the older group, similar among sexes and racial groups, and there was no association with the exposure to urban rodents. The antibodies anti-HTN serum-prevalence in low social economic level school children is high and confirm the circulation of hantaviruses in Salvador-Bahia, Brazil; the nonobservation of antibodies anti-SN indicates that the species are other than Sin Nombre Virus.

As hantaviroses são doenças emergentes nas Américas e, em todo o mundo, os casos clínicos descritos foram infreqüentes entre crianças. O objetivo de investigar a freqüência de escolares portadores de anticorpos (IgG) anti-hantavírus justifica-se porque poucos estudos soroepidemiológicos pesquisaram a infecção por hantavírus no grupo pediátrico. Nos espécimes séricos de 379 escolares, de duas Escolas públicas da cidade do Salvador, Bahia, foram pesquisados os anticorpos anti-Hantaan (HTN) e anti-Sin Nombre (SN). A soropositividade de anticorpos anti-HTN foi de 13,2% (50/379) e todos os escolares foram soronegativos para o vírus SN. A soropositividade anti-HTN aumentou proporcionalmente com a idade. Não houve associação entre a soropositividade anti-HTN e as características relacionadas à exposição a roedores urbanos. A soroprevalência de anticorpos anti-HTN nos escolares estudados foi elevada e reforçou a hipótese de circulação de hantavírus em Salvador. A não observação de portadores de anticorpos anti-SN indica, provavelmente, a circulação de outros sorotipos nesta região, mais relacionados antigenicamente ao sorotipo Hantaan.

Involvement of the central nervous system in dengue fever: three serologically confirmed cases from Fortaleza Ceará, Brazil.

Three cases of dengue fever involving the central nervous system (CNS) are reported. All occurred in 1994 during a dengue (DEN) epidemic caused by serotypes DEN-1 and DEN-2. The first case examined was a 17-year-old girl who complained of fever, nuchal rigidity and genital bleeding. Three blood samples were positive by anti-dengue IgM ELISA and showed hemagglutination-inhibition (HI) test titers > or = 1,280. The second case concerned a 86-year-old women with fever, muscle and joint pains, altered consciousness, syncope, nuchal rigidity and meningismus. Her blood sample showed an HI titer of 1:320 for flaviviruses, and an IgM ELISA positive for dengue. The third case was a 67-year-old women with fever, abnormal behaviour, seizures, tremor of extremities, thrombocytopenia, increased hematocrit and leukopenia. The patient suffered a typical case of dengue hemorrhagic fever with ensuing shock and a fatal outcome. A single blood sample showed HI antibodies of > or = 1,280 and an IgM ELISA positive for dengue. No virus could be isolated from any patient by inoculation of blood into C6/36 cells and suckling mice. No other agent of disease was encountered in the patient.

[Dengue epidemic in Fortaleza, Ceará: randomized seroepidemiologic survey]. / Epidemia de dengue em Fortaleza, Ceará: inquérito soro-epidemiológico aleatório.

OBJECTIVE: A seroepidemiological random survey was carried out in Fortaleza city, State of Ceará, Brazil, following an epidemic of dengue virus type 2 (DEN 2), with the purpose of evaluating the frequency of clinical manifestations (signs and symptoms) and the prevalence of dengue infection. METHOD: A questionnaire calling for information on address, sex, age, clinical, epidemiological and economic status was applied to the population, followed by venupuncture collection of 5-10 ml of blood for testing by hemagglutination-inhibition (HI). The sample was calculated to obtain a prevalence of 20% with relative risk of 10% and confidence interval of 95%. All information obtained was analyzed by computer using Epi Info 5.0, Lotus 123, Excel 5.0, and Stata software. RESULTS AND CONCLUSIONS: A total of 1,341 serum samples were obtained from nine Health Districts (SD) and tested by hemagglutination inhibition. Of these, 589 (44%) were positive and 752 (56%) negative. Of the positive results, 93 primary responses (PR) (7%) to DEN-2 and 496 secondary responses (SR) (37%) were observed. The global prevalence in the SD ranged from 21% to 71%. There were 41% (243/589) asymptomatic infections and 59% (346/589) symptomatic infections. Data analysis showed no difference in frequency by sex, age, on schooling, although a highly statistically significant difference was found as between the different social classes, the infection most commonly observed being among people of better social status. The stratification of positive cases showed greater prevalence of AI (p < 0.001) and SI (p < 0.0001) in both sexes, among people with SR rather than PR. The most prevalent symptoms were fever, headache, muscle pains, rash, dizziness, and joint pains. Moreover, itching, retro-bulbar pain, rash, and gingival bleeding, showed statistically significant differences. On the other hand, dizziness and joint pains were more associated in the patients with SR than PR, and statistically significant differences were also observed.

An epidemic of sylvatic yellow fever in the southeast region of Maranhao State, Brazil, 1993-1994: epidemiologic and entomologic findings.

Yellow fever virus transmission was very active in Maranhao State in Brazil in 1993 and 1994. An investigation was carried out to evaluate the magnitude of the epidemic. In 1993, a total of 932 people was examined for yellow fever from Maranhao: 70 were positive serologically, histopathologically, and/or by virus isolation, and another four cases were diagnosed clinically and epidemiologically. In Mirador (17,565 inhabitants), the incidence was 3.5 per 1,000 people (case fatality rate [number of deaths/number of cases diagnosed] = 16.4%), while in a rural yellow fever risk area (14,659 inhabitants), the incidence was 4.2 and the case-fatality rate was 16.1% (10 of 62). A total of 45.2% (28 of 62) asymptomatic infections were registered. In 1994, 49 serum samples were obtained and 16 cases were confirmed (two by virus isolation, two by seroconversion, and 12 by serology). No fatal cases were reported. In 1993, 936 potential yellow fever vectors were captured in Mirador and a single strain was isolated from a pool of Haemagogus janthinomys (infection rate = 0.16%). In 1994, 16 strains were isolated from 1,318 Hg. janthinomys (infection rate = 1.34%) and one Sabethes chloropterus (infection rate = 1.67%). Our results suggest that this was the most extensive outbreak of yellow fever in the last 20 years in Brazil. It is also clear that the lack of vaccination was the principal reason for the epidemic, which occurred between April and June, during the rainy season, a period in which the mosquito population in the forest increases.

[Dengue and its vectors in Brazil]. / La dengue et ses vecteurs au Brésil.

History of dengue in Brazil is covered from the first citations in the XIXth century to the great outbreaks of the last ten years. DEN-1 and DEN-4 viruses have been isolated for the first time in 1982 during an epidemic in Boa Vista, Roraima State. In 1986-1987, epidemics of dengue type 1 covered an extended area from Rio de Janeiro/Sào Paulo States to the North East States of Brazil. During 1990-1991, dengue type 2 epidemics have been notified in the South East (Rio de Janeiro/São Paulo) and in some States of the interior of the country (Mato Grosso do Sul, Tocantins). DEN-1 virus was also circulating the same year in São Paulo and Minas Gerais States. Recently (1994), an important outbreak has been studied in Ceará State, where DEN-2 and DEN-1 viruses have been isolated. In Rio de Janeiro and Ceara (1990 and 1994, respectively), it is probably the succession of infections by DEN-1 and DEN-2 viruses which has caused many DHF/DSS cases. The urban vector has always been the mosquito Aedes aegypti, from which 4, 7 and 16 strains of DEN-4, DEN-1 and DEN-2 have been isolated, respectively. In Brazil, transovarial transmission of dengue viruses by this species has not yet been shown to occur in nature.