Epidemiological study of infection by spotted fever group rickettsiae in dogs, horses and its ticks in the city of Resende, Rio de Janeiro state, Brazil

Autor: Cunha, Nathalie Costa da
Přispěvatelé: Fonseca, Adivaldo Henrique da
Jazyk: portugalština
Rok vydání: 2009
Předmět:
Zdroj: Biblioteca Digital de Teses e Dissertações da UFRRJ
Universidade Federal Rural do Rio de Janeiro (UFRRJ)
instacron:UFRRJ
Popis: Made available in DSpace on 2016-04-28T20:16:32Z (GMT). No. of bitstreams: 1 2009 - Nathalie Costa da Cunha.pdf: 1106704 bytes, checksum: acf94c83c9ed46a4ae020bccfdfe1db8 (MD5) Previous issue date: 2009-02-19 Funda??o Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro - FAPERJ Diseases caused by rickettsiae are widely distributed worldwide and are associated with hematophagous arthropods. The bacteria Rickettsia rickettsii is the most pathogenic of the spotted fever group (SFG). In order to know the factors that led to the occurrence of the disease in this area and acquire more knowledge in the epidemiology of SF in Brazil, as their vectors and the sentinel animals, this study have had the following objectives: verify the occurrence of dogs and horses serological reactive to R. rickettsii, using the technique of indirect immunofluorescence assay (IFA); evaluate the potential of dogs and horses as sentinels for the occurrence SF; better understand the population of ixodidae in dogs and horses and evaluate by molecular tools the presence of the spotted fever group rickettsiae (SFGR) in ticks. It was found that 29 (27.62%) sera of dogs were reactive, with titles ranging from 1:64 to 1:4096 and 76 sera (72.38%) were not reactive. In the analysis of horses there was a total of 9 (9.4%) animals reactive and 87 (90.6%) not reactive to the IFA. It was collected a total of 470 ticks of dogs, which showed a percentage of infestation of 44%. It was identified the species Rhipicephalus sanguineus, Amblyomma cajennense, A. aureolatum, A. ovale and Rhipicephalus (Boophilus) microplus and nymphs of Amblyomma sp., R. sanguineus and R. (B.) microplus, and 33 larvae. A total of 975 ticks were collected from horses, the species: A. cajennense, R. (B.) microplus and Dermacentor (Anocentor) nitens. It was also collected nymphs of Amblyomma sp., R. (B.) microplus and D. (A.) nitens, and 15 larvae. Considering the total number of horses observed, 71% were parasitized by ticks. The polymerase chain reaction (PCR) was performed on samples of blood and ticks of dogs that had positive serology. Thus, it was submitted to the technique 82 ticks. Only one tick of the species R. sanguineus showed PCR positive, and amplified for the four primers studied (ompA, ompB, gltA and htrA). This tick infested canine founded the property where there were the cases of SF. The rate of infection in ticks was 1.22%. The sequence had similarity of 99,3% with deposits in GenBank of R. rickettsii. Based on the results observed in the studied region, it can be concluded that dogs were important sentinels for the agent of SF; canines regular contact with forests and pastures positively influenced the reactive infection by R. rickettsii; dogs coming from properties at least six kilometers away from the outbreak were reactive to SFGR, confirming the concept of endemic area; canine remained reactive to the SFGR to at least one year after the occurrence of five cases of Brazilian spotted fever diagnosed in 2006; the population of ixodidae found corroborates with other studies in areas endemic for SF. The presence of the bacteria R. rickettsii in the tick R. sanguineus in natural conditions have demonstrated a likely chance of participation of the transmission vector of R. rickettsii to humans in the area of study. As enfermidades causadas por rickettsias s?o amplamente distribu?das no mundo e est?o associadas a artr?podes hemat?fagos. A bact?ria Rickettsia rickettsii ? a mais patog?nica das rickettsias do grupo da febre maculosa (RGFM). No Munic?pio de Resende, Estado do Rio de Janeiro, cinco casos de febre maculosa (FM) ocorreram em uma mesma fam?lia. Com intuito de conhecer os fatores que levaram ? ocorr?ncia da doen?a nesta localidade e adquirir mais conhecimentos na epidemiologia da FM no Brasil, o presente estudo teve os seguintes objetivos: verificar a ocorr?ncia de caninos e equinos reativos sorologicamente ? R. rickettsii, utilizando a t?cnica de rea??o de imunofluoresc?ncia indireta (RIFI); avaliar o potencial dos caninos e equinos como sentinelas para a ocorr?ncia de FM; conhecer a fauna de ixod?deos dos c?es e equinos e avaliar por meio de ferramentas moleculares a presen?a de RGFM em carrapatos. Verificou-se que 29 (27,62%) dos soros caninos foram reativos, com t?tulos variando de 1:64 a 1:4096 e 76 (72,38%) soros foram n?o reativos. Na an?lise soroepidemiol?gica dos equinos observou-se um total de 9 (9,4%) animais reativos e 87 (90,6%) n?o reativos ? RIFI. Coletou-se um total de 470 carrapatos dos caninos, que apresentaram um percentual de infesta??o de 44%. Foram identificadas as esp?cies Rhipicephalus sanguineus, Amblyomma cajennense, A. aureolatum, A. ovale e Rhipicephalus (Boophilus) microplus e ninfas de Amblyomma sp., R. sanguineus e R.(B.) microplus e 33 larvas. Coletou-se um total de 975 carrapatos dos equinos, que apresentaram um percentual de infesta??o de 71%, pertencentes ?s seguintes esp?cies: A. cajennense, R.(B.) microplus e Dermacentor (Anocentor) nitens. Tamb?m foram coletadas ninfas de Amblyomma sp., R.(B.) microplus e D.(A.) nitens e 15 larvas. A rea??o em cadeia da polimerase (PCR) foi realizada em amostras de carrapatos dos caninos que apresentaram sorologia positiva, sendo submetidos ? t?cnica 82 carrapatos. Apenas um carrapato da esp?cie R. sanguineus apresentou-se positivo na PCR, tendo amplificado para os quatro marcadores estudados (ompA, ompB, gltA e htrA). Este carrapato infestava canino procedente da propriedade onde ocorreram os casos de FM. A taxa de infec??o nos carrapatos foi de 1,22%. A sequ?ncia teve similaridade de 99,3% com dep?sitos no GenBank de R. rickettsii. Com base nos resultados observados na regi?o estudada, pode-se concluir que os c?es foram importantes sentinelas para o agente da febre maculosa; o h?bito de caninos frequentarem matas e pastos influenciou positivamente na presen?a de anticorpos s?ricos anti-RGFM; os caninos provenientes de propriedades a pelo menos seis quil?metros de dist?ncia a partir do local de ocorr?ncia dos casos foram reativos a RGFM, confirmando o conceito de ?rea end?mica; caninos permaneceram reativos para RGFM pelo menos um ano ap?s a ocorr?ncia dos cinco casos de FM brasileira diagnosticados em 2006; a fauna de ixod?deos encontrada corrobora com dados de outros estudos em regi?es end?micas para FM; a presen?a, em condi??es naturais, de Rickettsia rickettsii no carrapato Rhipicephalus sanguineus indica uma poss?vel participa??o deste vetor na transmiss?o de R. rickettsii para humanos na ?rea estudada.
Databáze: OpenAIRE
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