Small mammals, ticks and rickettsiae in natural and human-modified landscapes: Diversity and occurrence of Brazilian spotted fever in Brazil.

We studied communities of small mammals and their ticks in endemic (E) and non-endemic (NE) areas for Brazilian spotted fever (BSF), aiming to infer if diversity parameters of parasites and hosts could be related to occurrence and prevalence of rickettsial infection, especially Rickettsia rickettsii. We compared E and NE areas in human-modified landscapes (HMLs) and natural areas (BIO) with no report of BSF cases. Composition and equitability were important components of diversity explaining differences among areas. The marsupial Didelphis albiventris was dominant in HMLs, but not in natural areas, and this opossum was the main host for the tick Amblyomma sculptum, principal vector of R. rickettsii, especially in E areas. Communities of ticks were dominated by A. sculptum, followed by Amblyomma dubitatum in E areas. In NE areas, this dominance was inverted, with more A. dubitatum than A. sculptum infesting small mammals, but the numbers of ticks were much lower than in E areas. Composition and abundance of ticks in natural areas were very dissimilar from HMLs, with the lowest tick burdens. Didelphis albiventris in E areas presented higher seroprevalence and endpoint titres against R. rickettsii than in other areas. At least three Rickettsia species, non-pathogenic to humans, were detected in natural areas (Rickettsia bellii, Rickettsia amblyommatis and 'Candidatus Rickettsia andeanae'), and only one non-pathogenic species in HMLs (R. bellii). Our results suggest that higher diversity of ticks, hosts and rickettsiae could be relevant factors in buffering the effect in BSF occurrence. Particularly for D. albiventris, its importance has to be quantified in further studies considering the epidemiological scenario of BSF.

Aspectos clínico-epidemiológicos de um cluster de febre maculosa brasileira, ocorrido no município de Americana, São Paulo, Brasil, 2018 / Clinical and epidemiological aspects of a cluster of brazilian spotted fever, which occurred in the city of Americana, São Paulo, Brazil, 2018

Objetivos: descrever os principais aspectos clínicos, laboratoriais e epidemiológicos relacionados à ocorrência de um cluster de febre maculosa brasileira (FMB) na cidade de Americana/SP, em 2018. Métodos: realizou-se uma análise descritiva baseada na revisão das informações constantes nos registros do Sistema de Informação de Agravos de Notificação ­ SINAN e nos relatórios de investigações epidemiológicas obtidos junto ao banco de dados da Unidade de Vigilância em Saúde Municipal. Resultados: esse cluster ocorreu em um fragmento de mata ciliar situado na confluência dos rios Atibaia e Jaguari, entre os dias 21/4/2018 e 31/5/2018. Durante esse período, ocorreram 15 casos positivos de FMB, com registro de 11 óbitos, atingindo uma taxa de letalidade de 73%. O sexo masculino representou 93% dos pacientes, e a faixa etária mais afetada foi a de indivíduos acima dos 30 anos (67%), seguindo-se o percentual de 13% para as faixas de 1 a 4 e 5 a 9 anos, e 7% para pessoas de 20 a 29 anos. Os principais sinais clínicos observados foram febre (100%); cefaléia (80%) e mialgia (73,33%). Conclusão: foi possível delinear o perfil epidemiológico dos indivíduos a serem alcançados nas campanhas de educação em saúde, com enfoque para medidas preventivas visando à redução de frequência nas áreas de risco para parasitismo humano por carrapatos vetores da FMB.

Objective: describe the main clinical, laboratory and epidemiological aspects related to the occurrence of a cluster of brazilian spotted fever (FMB) in the city of Americana/SP, in 2018. Methods: A descriptive analysis was performed based on the review of the information contained in the records of the Notification Disease Information System (SINAN) and in the reports of epidemiological investigation obtained from the Municipal Health Surveillance Unit database. Results: This cluster occurred in a riparian forest fragment located at the confluence of the Atibaia and Jaguari rivers, between 04/21/2018 and 05/31/2018. During this period there were 15 positive cases of BSF, with a record of 11 deaths, reaching a lethality rate of 73%. Males represented 93% of the patients and the most affected age group was that of individuals over 30 years old (67%), followed by 13% for the age groups 01 to 04 and 05 to 09 years old, and 7 % for people from 20 to 29 years old. The main clinical signs observed were fever (100,00%); headache (80,00%) and myalgia (73,33%). Conclusion: It was possible to outline an epidemiological profile of individuals to be reached in health education campaigns, with a focus on preventive measures aimed at reducing frequency in areas at risk for human parasitism by BSF vector ticks.

Epidemiology of capybara-associated Brazilian spotted fever.

BACKGROUND: Brazilian spotted fever (BSF), caused by the bacterium Rickettsia rickettsii, has been associated with the transmission by the tick Amblyomma sculptum, and one of its main hosts, the capybara (Hydrochoerus hydrochaeris). METHODS: During 2015-2019, we captured capybaras and ticks in seven highly anthropic areas of São Paulo state (three endemic and four nonendemic for BSF) and in two natural areas of the Pantanal biome, all with established populations of capybaras. RESULTS: The BSF-endemic areas were characterized by much higher tick burdens on both capybaras and in the environment, when compared to the BSF-nonendemic areas. Only two tick species (A. sculptum and Amblyomma dubitatum) were found in the anthropic areas; however, with a great predominance of A. sculptum (≈90% of all ticks) in the endemic areas, in contrast to a slight predominance of A. dubitatum (≈60%) in the nonendemic areas. Tick species richness was higher in the natural areas, where six species were found, albeit with a predominance of A. sculptum (≈95% of all ticks) and environmental tick burdens much lower than in the anthropic areas. The BSF-endemic areas were characterized by overgrowth populations of A. sculptum that were sustained chiefly by capybaras, and decreased populations of A. dubitatum. In contrast, the BSF-nonendemic areas with landscape similar to the endemic areas differed by having lower tick burdens and a slight predominance of A. dubitatum over A.sculptum, both sustained chiefly by capybaras. While multiple medium- to large-sized mammals have been incriminated as important hosts for A. sculptum in the natural areas, the capybara was the only important host for this tick in the anthropic areas. CONCLUSIONS: The uneven distribution of R. rickettsii infection among A. sculptum populations in highly anthropic areas of São Paulo state could be related to the tick population size and its proportion to sympatric A. dubitatum populations.

Avaliação da mobilidade de escorpiões Tityus serrulatus em área de infestação urbana de Americana, São Paulo, Brasil / Evaluation of the mobility of scorpions Tityus serrulatus in urban infestation area of Americana, São Paulo, Brazil

Introdução: A avaliação da dispersão e das modificações de habitat das espécies de escorpiões de importância médica acrescentam importantes informações sobre sua ocorrência em áreas urbanas. Objetivo: A mobilidade da espécie Tityus serrulatus foi avaliada em focos de infestação de áreas antropizadas do município de Americana, Estado de São Paulo. Métodos: Os espécimes foram capturados em um cemitério municipal, sendo individualmente marcados, em quatro grupos de 200 indivíduos, com cores diferenciadas. Posteriormente, foram soltos no centro da respectiva área em que foram capturados, sem controle individual. Foram realizadas varreduras periódicas em uma área circular, com raio de leitura estabelecido a cada 4 metros, havendo o registro de localização dos animais marcados que foram recapturados. Os dados experimentais foram coletados no período de agosto de 2014 a novembro de 2016, durante 28 meses de atividades (359 horas de observação). As recapturas dos espécimes foram realizadas em período diurno, no primeiro ano (221 horas), por meio da inspeção de 5.021 sepulturas e em período noturno no segundo ano (138 horas), com 3.053 sepulturas vistoriadas. Resultados: Foram evidenciadas, uma distância mínima de 2,13 metros no 1º dia de leitura e uma distância máxima de 29,34 metros no 68º dia de leitura, em foco de infestação urbana. Conclusão: Os resultados obtidos neste experimento contribuem para um melhor entendimento da dispersão de T. serrulatus em áreas urbanas, visando o controle e a prevenção de riscos de acidentes junto à população, com enfoque nas estratégias de controle químico dessa espécie.(AU)

Introduction: The assessment of the dispersion and habitat modifications of the species of scorpions of medical importance adds important information about their occurrence in urban areas. Objective: The mobility of the species Tityus serrulatus was evaluated in outbreaks of infestation of anthropic areas of the city of Americana, state of São Paulo, Brazil. Methods: The specimens were captured in a municipal cemetery and individually marked in four groups of 200 individuals with different colors. Later on, they were released in the centroid of the respective area in which they were captured, without individual control. Periodic sweeps were performed in a circular area, with a radius established every 4 meters, with the record of the location of the recaptured tagged animals. The experimental data were collected from August 2014 to November 2016, during 28 months of activities (359 observation hours). Sample recaptures were carried out in the first year (221 hours) through the inspection of 5,021 graves and at night in the second year (138 hours), with 3,053 graves inspected. Results: A minimum distance of 2.13 meters on the 1st day of reading and a maximum distance of 29.34 meters on the 68th day of reading were registered, in a focus area of urban infestation. Conclusion: The results obtained in this experiment contribute to a better understanding of the dispersal of T. serrulatus in urban areas, aiming at the control and prevention of risk of accidents for the population, focusing on the strategies of chemical control of this species.(AU)

Evaluation of an association of alpha-cypermethrin and flufenoxuron for tick control in an area at risk of Brazilian spotted fever.

Brazilian spotted fever (BSF) is an endemic anthropozoonosis caused by Gram-negative bacteria (Rickettsia rickettsii) that is associated with the risk of human infection by ticks. In the city of Americana, São Paulo (SP), Brazil, there were 12 cases (67% lethal) between 2004 and 2015. This study evaluated the effectiveness of control over tick infestations in an area at risk of BSF, in a field trial on an association of alpha-cypermethrin (3%) and flufenoxuron (3%) (Tenopa®) conducted in Americana. The infestation levels of the target species (Amblyomma sculptum and Amblyomma dubitatum) in the field trial were evaluated through acarological surveys (CO2 traps) on days 0, 22, 43 and 62 after treatment, both in the treatment area and in a control area. In the treatment area, the insecticide formulation was applied using a motorized sprayer, at the dosage of 80mL/10L of water per 200m2. These surveys in the treatment area showed that there were reductions in the infestation levels of the adult stage on days 22 (33%), 43 (87%) and 62 (70%) and immature stages (nymphs and larvae) on days 22 (54%), 43 (87%) and 62 (97%), in relation to day zero and to infestation levels in the control area. This study demonstrated that the product applied was effective for reducing the environmental infestation of ticks and that this effect persisted two months after a single application in areas of proven risk of BSF.

Epidemiological surveillance of capybaras and ticks on warning area for Brazilian spotted fever.

AIM: The vulnerability of tropical developing countries to the emerging disease constitutes a critical phenomenon in which the invasion of wild niches by human hosts, contributes to expansion of zoonotic diseases, such as the Brazilian spotted fever (BSF). This study performed a diagnosis of species occurrence of their hosts (Hydrochoerus hydrochaeris) and vectors (Amblyomma sculptum and Amblyomma dubitatum) on the warning area for this reemerging disease in Brazil. MATERIALS AND METHODS: The study was conducted in a warning area for BSF in the city of Americana, São Paulo state. The occurrence of capybaras was registered by use of binoculars and GPS equipment and 24 acarological researches were performed through 180 CO2 traps. Samples of adult ticks were dissected for salivary glands removal, DNA extraction, and evaluation by polymerase chain reaction (PCR) being tested by initial gltA-PCR, ompA-PCR, and Rickettsia bellii-specific PCR, with the positive samples subjected to sequencing. RESULTS: Eleven clusters of capybaras (total of 71 individuals), were observed along the riparian of Ribeirão Quilombo and 7,114 specimens of A. sculptum and 7,198 specimens of A. dubitatum were collected in this same area. About 568 samples of adult ticks were dissected for salivary glands removal, DNA extraction and evaluation by gltA-PCR, with results of 1.94% (11/568) of positive samples. Results for the initial gltA-PCR indicated none positive sample to Rickettsia species into A. sculptum and 11 positive samples to A. dubitatum. These samples were negative to the ompA-PCR and positive to the Rickettsia bellii-specific PCR protocol and subjected to DNA sequencing, whose result indicated 100% similarity to Rickettsia bellii. The distribution of tick species A. sculptum and A. dubitatum was configured regarding to the biotic potential of the riparian areas, measuring the risks for BSF in peri-urban areas of Americana. CONCLUSION: These results confirmed a status of epidemiological warning with a strong association of the amplifiers hosts of Rickettsia and tick vectors for the transmission of BSF to humans in this region.

Monitoramento epidemiológico de carrapatos em área de risco para Febre Maculosa Brasileira, Americana – SP / Epidemiological monitoring of ticks in public woods in a risk area for Brazilian Spotted Fever

A importância da Febre Maculosa Brasileira (FMB) aumentou significativamente, pela crescente relação do número de casos e óbitos diagnosticados e elevada taxa de letalidade em São Paulo entre 2000 e 2009, agravada pela expansão das áreas de transmissão, com modificação nas características ecoepidemiológicas e ocorrência de casos em áreas urbanas e periurbanas. Este informe apresenta resultados do monitoramento de um bosque público no município de Americana/SP onde, na ausência de hospedeiros amplificadores de rickéttsias (capivaras) por meio de controle estabelecido e após dois anos de monitoramento por pesquisas acarológicas, modificou-se o status epidemiológico desta área infestada por carrapatos e de risco epidemiológico para FMB para área não infestada e livre para frequência humana, com nulidade de parasitismo humano por Amblyomma cajennense e Amblyomma dubitatum...

Environmental infestation and rickettsial infection in ticks in an area endemic for Brazilian spotted fever.

Brazilian spotted fever (BSF), caused by Rickettsia rickettsii, is endemic in the municipality of Americana, southeastern Brazil, where the disease is transmitted by the tick Amblyomma cajennense. This study evaluated the tick fauna and rickettsial infection in free-living ticks that were captured monthly using dry ice traps in areas endemic for BSF in Americana, from July 2009 to June 2010. Two tick species were captured: A. cajennense (6,122 larvae; 4,265 nymphs; 2,355 adults) and Amblyomma dubitatum (7,814 larvae; 3,364 nymphs; 1,193 adults). The immature stages of A. cajennense and A. dubitatum had similar distribution through the 12-month period, with larvae of both species collected in highest numbers between April and July, and nymphs between June and October. The highest numbers of A. cajennense adults were collected between October and December, whereas A. dubitatum adults were collected in relatively similar numbers throughout the 12-month period. Rickettsial infection was evaluated by means of PCR in 1,157 A. cajennense and 1,040 A. dubitatum ticks; only 41 (3.9%) A. dubitatum were found to be infected by Rickettsia bellii. The present study showed that the areas of Americana that are endemic for BSF are characterized by high environmental burdens of A. cajennense and A. dubitatum.

Environmental infestation and rickettsial infection in ticks in an area endemic for brazilian spotted fever / Infestação ambiental e infecção por rickéttsias em carrapatos de área endêmica para Febre Maculosa Brasileira

Brazilian spotted fever (BSF), caused by Rickettsia rickettsii, is endemic in the municipality of Americana, southeastern Brazil, where the disease is transmitted by the tick Amblyomma cajennense. This study evaluated the tick fauna and rickettsial infection in free-living ticks that were captured monthly using dry ice traps in areas endemic for BSF in Americana, from July 2009 to June 2010. Two tick species were captured: A. cajennense (6,122 larvae; 4,265 nymphs; 2,355 adults) and Amblyomma dubitatum (7,814 larvae; 3,364 nymphs; 1,193 adults). The immature stages of A. cajennense and A. dubitatum had similar distribution through the 12-month period, with larvae of both species collected in highest numbers between April and July, and nymphs between June and October. The highest numbers of A. cajennense adults were collected between October and December, whereas A. dubitatum adults were collected in relatively similar numbers throughout the 12-month period. Rickettsial infection was evaluated by means of PCR in 1,157 A. cajennense and 1,040 A. dubitatum ticks; only 41 (3.9%) A. dubitatum were found to be infected by Rickettsia bellii. The present study showed that the areas of Americana that are endemic for BSF are characterized by high environmental burdens of A. cajennense and A. dubitatum.

A Febre Maculosa Brasileira (FMB) é uma antropozoonose endêmica no município de Americana/SP, causada pela bactéria Rickettsia rickettsii e transmitida pelo carrapato Amblyomma cajennense. Este estudo avaliou a fauna de carrapatos e a infecção por riquétsias em carrapatos de vida livre capturados mensalmente com armadilhas de CO2, em áreas de risco para FMB de Americana, de julho de 2009 a junho de 2010. Duas espécies foram capturadas, A. cajennense (6.122 larvas; 4.265 ninfas; 2.355 adultos) e Amblyomma dubitatum (7.814 larvas; 3.364 ninfas; 1.193 adultos). Os estágios imaturos de A. cajennense e A. dubitatum apresentaram uma distribuição anual semelhante, com larvas de ambas as espécies sendo coletadas em maior número no período de abril a julho e ninfas de junho a outubro. Maior número de adultos de A. cajennense foi coletado de outubro a dezembro, enquanto que os adultos de A. dubitatum foram coletados em número relativamente semelhante durante todo o ano. A infecção por Rickettsia foi avaliada pela PCR em 1157 carrapatos A. cajennense e 1040 A. dubitatum, com apenas 41 (3,9%) A. dubitatum infectados com Rickettsia bellii. Este estudo demonstrou que as áreas de risco para FMB de Americana são caracterizadas por elevadas infestações ambientais de A. cajennense e A. dubitatum.

Estratégias de controle do escorpionismo no município de Americana, SP / Scorpion control strategies in the city of Americana, SP

Os acidentes por escorpiões tornaram-se agravos de uma maior atenção para a Saúde Pública, visto que 30% das notificações expressas pelos mais de 100.000 acidentes por animais peçonhentos e quase 200 óbitos registrados por ano no Brasil devem-se ao escorpionismo. Em Americana/SP, as ações desencadeadas no âmbito da vigilância epidemiológica de escorpiões, desempenharam uma influência direta na redução do número de acidentes escorpiônicos; como também no campo da pesquisa biomédica, com o advento de um dispositivo de luz ultravioleta para captura noturna de escorpiões, omunicípio tornou-se o maior fornecedor de escorpiões vivos ao Instituto Butantan, para fins de produção de soro antiescorpiônico. Neste trabalho apresentam-se dados sobre a distribuição e o perfil epidemiológico dos acidentes por escorpiões e sobre resultados das estratégias de controle voltadas à prevenção e redução do número de acidentes escorpiônicos no município