Genetic diversity, population structure and rickettsias in Amblyomma ovale in areas of epidemiological interest for spotted fever in Brazil.

Amblyomma ovale (Ixodida: Ixodidae) Koch, 1844 is widely-reported in the neotropical region and is the main vector in the epidemic cycle of Rickettsia parkeri strain Atlantic rainforest, a bioagent of a milder variety of spotted fever (SF). Because species with wide geographical distributions are known to exhibit variations that influence their vectorial capacity, the present study aimed to analyze genetic diversity and rickettsia infection of A. ovale collected during the investigation and surveillance of SF cases in the Cerrado and Atlantic rainforest (ARF) Brazilian biomes. Samples had their DNA extracted, amplified and sequenced for 16S rDNA, 12S rDNA, cytochrome oxidase subunit II and D-loop markers for tick analyses, as well as the gltA, htrA, ompA and ompB genes for rickettsia detection. Between 11 and 33 A. ovale haplotypes were identified, all of them exclusive to areas within individual analyzed biome areas. The A. ovale populations appeared to be structured, with Cluster I restricted to Cerrado + ARF isolated in Caatinga and Cluster II to ARF continuous area. Rickettsia bellii, R. parkeri strain Atlantic rainforest (first report for Goiás state, Cerrado), Rickettsia asemboensis (first record in A. ovale for Brazil) and Rickettsia felis (first detection in this ixodid) were identified. A. ovale clusters were not associated with rickettsia types.

Amblyomma sculptum: genetic diversity and rickettsias in the Brazilian Cerrado biome.

Amblyomma sculptum (Ixodida: Ixodidae) Berlese, 1888 is the most important tick vector in Brazil, transmitting the bioagent of the most severe form of spotted fever (SF) in part of the Cerrado (in the states of Minas Gerais and São Paulo). In another part of the Cerrado (Central-West region of Brazil), a milder form of SF has been recorded. However, neither the rickettsia nor the vector involved have been characterized. The aim of the current study was to analyse genetic variation and the presence of rickettsia in A. sculptum in Cerrado, from silent areas and with the milder form of SF. Samples were subjected to DNA extraction, amplification and sequencing of 12S rDNA, cytochrome oxidase subunit II and D-loop mitochondrial genes (for tick population analyses), and gltA, htrA, ompA and gene D (sca4) genes for rickettsia researches. Exclusive haplotypes with low frequencies, high haplotype diversity and low nucleotide diversity, star-shaped networks and significant results in neutrality tests indicate A. sculptum population expansions in some areas. Rickettsia amblyommatis, Candidatus Rickettsia andeanae and Rickettsia felis were detected. The A. sculptum diversity is not geographically, or biome delimited, pointing to a different potential in vector capacity, possibly associated with differing tick genetic profiles.

Polyenvironmental and polygenic risk scores and the emergence of psychotic experiences in adolescents.

Psychotic experiences (PE) are forms of hallucinations and delusions neither reaching the intensity and functional impairment required to be regarded as full psychotic symptoms nor a psychotic disorder. Here we investigated the ability to predict PE using multiple models (regressions, mediation and moderation) using polygenic risk score for psychotic experiences (PE-PRS), polygenic risk score for schizophrenia (SCZ-PRS), and polyenvironmental risk score (PERS) in youth from a Brazilian sample. The scores were not able to predict outcome, either when both scores were combined (PERS + PE-PRS and PERS + SCZ-PRS) or separately. Our results show that there is no association between PE and PRS or PERS among adolescents in our Brazilian sample. The lack of association may be a result of the absence of better representativeness regarding genetic and environmental factors of our population.

Predictive Factors for Fatal Tick-Borne Spotted Fever in Brazil.

In Brazil, two pathogenic Rickettsia species have been identified causing tick-borne spotted fever (SF). The aetiological agent Rickettsia rickettsii causes serious illness, particularly in the south-eastern region of the country. Moreover, the Rickettsia sp. strain Atlantic Rainforest cause milder clinical manifestations in south-eastern, south and north-east regions. This study has sought to analyse predictive factors for fatal SF. A case-control study was performed using disease notification records in Brazil. The cases included were individuals with laboratory confirmation and fatal progression of SF, while the controls included individuals with SF who were cured. A total of 386 cases and 415 controls were identified (1 : 1.1), and the cases and controls were similar in age. The factors identified as being protective against death were reported presence of ticks (odds ratio [OR], 0.60; 95% confidence interval [CI], 0.41-0.88), residing in urban areas (OR, 0.47, 95% CI, 0.31-0.74) and presenting lymphadenopathy (OR, 0.43; 95% CI, 0.23-0.82). Males exhibited a greater chance of death (OR, 1.57; 95% CI, 1.13-2.18), as did patients who were hospitalized (OR, 10.82; 95% CI, 6.38-18.35) and who presented hypotension or shock (OR, 10.80; 95% CI, 7.33-15.93), seizures (OR, 11.24; 95% CI, 6.49-19.45) and coma (OR of 15.16; 95% CI, 8.51-27.02). The study demonstrates the severity profile of the SF cases, defined either as the frequency of hospitalization (even in cases that were cured) or as the increased frequency of the clinical complications typically found in critical patients. Opportune clinical diagnosis, a careful evaluation of the epidemiological aspects of the disease and adequate care for patients are determining factors for reducing SF fatality rates.

Epidemiological Profile of Wild Rabies in Brazil (2002-2012).

Rabies is one of the most important zoonosis in the world with high impact on public health. Studies report the presence of Lyssavirus in reservoirs of the wild cycle, highlighting the role of wild canines, marmosets, and vampire and non-vampire bats as potential vectors of the disease to domestic animals and human beings. Therefore, the reintroduction of rabies in urban environments from reservoirs of the wild cycle is a matter of concern. This study describes the profile of rabies cases documented in Brazil from 2002 to 2012, with emphasis on the wild transmission cycle of the disease. We carried out a descriptive study using records with information on the time of infection, persons with infection and location of confirmed cases of rabies in humans and animals, as well as data on anti-rabies treatments obtained from the Information System of Notifiable Diseases (Sinan) database. Within the study period, 82 cases of rabies transmitted by wild animals to humans were reported, predominantly in rural areas of the northern and north-eastern regions. Of the cases in humans, 72% did not receive post-exposure prophylaxis. Among wild mammals, vampire bats were the most frequent vectors of the disease. In the north-east region, 460 terrestrial wild mammals were reported with confirmed rabies. Over the study period, 1703 bats were reported to carry the rabies virus. In the south-east region, the most frequently reported carriers of the virus were non-vampire bats. The midwest and northern regions presented a lower number of records of rabies cases among terrestrial wild mammals. However, the high number of rabies cases among bovines reflects the role of the vampire bat as a maintainer of the rabies virus in the rural cycle. The present results are key to adjust the planning of rabies control in Brazil to the current epidemiological trends.

Cocaine mutagenicity and hepatocarcinogenicity evaluations in rodents.

The mutagenicity (clastogenicity) and the carcinogenicity (promoting potential) of cocaine were evaluated, respectively, by the mouse bone marrow micronucleus test (study I) and by the initiated rat liver bioassay (study II). In study I, two administration routes (i.p. and i.v.) and two sampling times (24 and 48 hours) after cocaine treatment were studied. Swiss male mice were treated with cocaine at doses of 0, 18, 37, and 75 mg/kg and 0, 2, 4, and 8 mg/kg by i.p. and i.v. routes, respectively. No significant differences were observed between treated and negative control groups regarding the frequencies of micronuclei and the polichromatic/normochromatic erythrocyte (PCE/NCE) ratios. In study II, the development of putative preneoplastic foci of hepatocytes expressing the enzyme glutathione S-transferase placental form (GST-P+) was utilized as the end-point marker in a 8-week rat liver bioassay. The animals were initiated for carcinogenesis by a single i.p. sub-carcinogenic dose of diethylnitrosamine (DEN). After a 6-week exposure to 5 or 10 mg/kg of cocaine i.v. twice a week there was no enhancement of GST-P+ foci development above the values of the control DEN-only treated animals. Also, cocaine did not induce any toxicity as evidenced by the absence of alterations of rat body and liver weights and of liver biochemical function and morphology. The results suggest that cocaine does not have a mutagenic effect on the mouse bone marrow cells or promoting activity on the rat hepatocarcinogenesis process.