Publications by authors named "Adivaldo H da Fonseca"

Human contact with wild animals in synanthropic habits is often mediated by arthropod vectors such as ticks. This is an important method of spreading infectious agents that pose a risk to human health. Thus, this study aimed to molecularly detect Ehrlichia spp.

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The present study aimed to describe the occurrence of Borrelia spp. in cattle in the states of Minas Gerais and Pará in southeastern and northern Brazil, respectively. Bovine whole blood samples were examined by blood smear and polymerase chain reaction (PCR) to detect the flagellin B (flaB) gene of Borrelia spp.

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This study evaluates the presence of bacterial and protozoan agents in ticks and fleas found on wild animals in the state of Rio de Janeiro, Brazil. These ectoparasites were collected on mammal species Hydrochoerus hydrochaeris, Tapirus terrestris, Dicotyles tajacu, Didelphis aurita, Cuniculus paca, Cerdocyon thous, and Coendou prehensilis, and on the terrestrial bird Dromaius novaehollandiae. Ticks and fleas were identified morphologically using specific taxonomic keys.

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Background: Canine monocytic ehrlichiosis (CME) is caused by the tick-borne pathogen Ehrlichia canis, an obligate intracellular Gram-negative bacterium of the family Anaplasmataceae with tropism for canine monocytes and macrophages. The trp36 gene, which encodes for the major immunoreactive protein TRP36 in E. canis, has been successfully used to characterize the genetic diversity of this pathogen in different regions of the world.

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Dogs are important in the epidemiology of tick-borne diseases, playing a significant role mainly in endemic areas of rickettsiosis and borreliosis, and serving as sentinels in epidemiological surveys. We analyzed the distribution of Rickettsia and Borrelia spp. in dogs and their ticks in the municipalities of Guaxupé, Minas Gerais, and Tapiratiba, São Paulo, Brazil, two areas non-endemic for Baggio-Yoshinari Syndrome (BYS) and rickettsiosis.

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Article Synopsis
  • Various zoonotic diseases are emerging or reemerging, with equids potentially exposed more frequently than humans due to their connection with disease-carrying vectors, which poses risks to both public and animal health.
  • A study analyzed 569 equids in northeastern Brazil, using blood samples to detect pathogens like Borrelia, Rickettsia, and Leishmania through serological and PCR methods, while also examining infection factors through statistical models.
  • Results showed significant frequencies of positivity for Rickettsia (33.4%) and Borrelia (13.9%), with males and certain animals showing protection against specific pathogens, highlighting the importance of equids as sentinels for zoonotic diseases in that region.
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This study aimed to evaluate the infection of the marsupial Monodelphis domestica (the gray short-tailed opossum) by Rickettsia parkeri and its role as an amplifier of the bacterium for Amblyomma ticks. Ten M. domestica males were inoculated with phosphate-buffered saline (PBS) and 10 Vero cells infected with R.

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This study aims to evaluate the infection's clinical parameters and genetic diversity of msp1α of the AmRio1 strain in acute and chronic infections in cattle and ticks. A calf experimentally infected with the A. marginale AmRio1 strain was monitored during acute infection, and the presence of the msp1α gene was verified in the semi-nested polymerase chain reaction (PCR) during the acute and persistent phases of infection.

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Article Synopsis
  • Equine piroplasmosis, caused by Theileria equi and Babesia caballi, poses a significant threat to the horse industry and affects international horse trade.
  • A study in western Cuba tested 100 horses, revealing 73% positive for T. equi, 25% for B. caballi, and 20% with dual infections, while also identifying tick infestations.
  • This research is the first to molecularly detect both B. caballi and T. equi in Cuban horses, indicating high prevalence and suggesting various genotypes of T. equi are present in the region.
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  • Borrelia burgdorferi sensu stricto is identified as the primary cause of Lyme disease in the USA, while a similar spirochete is suspected to cause Baggio-Yoshinari syndrome in Brazil, with both transmitted by ticks.
  • A study conducted on 367 horses in Sinop, Mato Grosso found a significant prevalence (54.04%) of IgG antibodies against B. burgdorferi, indicating the presence of the pathogen among local horse populations.
  • Despite a high seroprevalence, molecular analyses via PCR showed no reactive samples, highlighting a discrepancy between serological and molecular detection methods, and identified leisure/sport activities as a potential risk factor for infection.
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This study aimed to evaluate, by means of artificial feeding, the interaction between a pathogenic rickettsia and the hard tick R. microplus. We used partially engorged females fed on calves free of Rickettsia spp.

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The objective of this study was to determine the prevalence of antibodies to Neospora caninum and Toxoplasma gondii among 500 cattle (Bos indicus) and 500 buffaloes (Bubalus bubalis) using the indirect fluorescent antibody test (IFAT) technique. Blood samples from were collected from water buffalo and cattle in 10 municipalities in the northern region of Brazil. The frequency of cattle and water buffaloes seropositive for Neospora caninum in Pará state, Brazil, was 55% and 44%, respectively, and the frequency of cattle and water buffaloes seropositive for Toxoplasma gondii was 52% and 39%, respectively.

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  • The study aimed to evaluate how fluazuron affects pesticide detoxification enzymes in two strains of cattle ticks, one susceptible and one resistant.
  • Significant increases in mixed-function oxidases (MFO) and esterases activity were observed in the resistant strain compared to the susceptible strain, particularly in eggs and larvae.
  • The findings suggest that detoxification mechanisms in ticks vary with development stages and are linked to resistance against fluazuron.
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Anaplasma marginale is the most prevalent pathogen transmitted by ticks in cattle in tropical and subtropical regions of the world. However, the tick species involved in the transmission of A. marginale in buffaloes in Brazil have not been identified.

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The establishment of laboratory colonies of ticks is often hampered by their lack of adaptation to alternative hosts. The aim of this study was to artificially feed partially engorged Dermacentor (Anocentor) nitens females through plastic tips, and to identify what are the optimal conditions of application of this technique to get as much as possible close to the natural conditions. The technique of artificial feeding through plastic tips allowed the engorgement of D.

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Klossiella tejerai Scorza, Torrealba & Dagert, 1957 is a primitive coccidian parasite reported from the New World marsupials Didelphis marsupialis (Linnaeus) and Marmosa demerarae (Thomas). The current work describes K. tejerai from the Brazilian common opossum Didelphis aurita (Wied-Neuwied) in Southeastern Brazil, evidencing the coccidial dispersion across opossums of the same family.

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This study aimed to evaluate season, breed, number of lactations and milk production as risk factors relating to Rhipicephalus microplus infestation in dairy cows during the peripartum. Eighty-four animals were randomly selected through proportional stratified sampling. All engorged and partially engorged female R.

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Article Synopsis
  • The study investigates the prevalence of various parasitic diseases in water buffaloes in northern Brazil, focusing on Toxoplasma gondii, Neospora caninum, Anaplasma marginale, Babesia bigemina, and Babesia bovis.
  • A total of 4,796 blood samples from buffaloes across five provinces were analyzed using two methods: IFAT and ELISA, revealing significant serological prevalence rates for the diseases.
  • The findings provide crucial data for managing and controlling these bovine pathogens, which is essential for the health of the buffalo population in the region.
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The prevalence of and possible risk factors for tuberculosis were studied in water buffalo from Pará, Brazil. In this study, 3,917 pregnant and nonpregnant female Murrah and Mediterranean buffaloes were studied; 2,089 originated from Marajó Island, and 1,108 were from the mainland. The comparative cervical tuberculin test was used as a diagnostic test for tuberculosis in these animals.

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Anaplasma marginale is endemic in tropical and subtropical areas around the world. Some studies have suggested that cows during peripartum may present a transient immunosuppression state and development of clinical signs of anaplasmosis. The aim of this study was to investigate the relationship between some risk factors and the seroprevalence of A.

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Bovine anaplasmosis, caused by Anaplasma marginale, occurs in tropical and subtropical regions throughout the world and is a major constraint on cattle production in many countries. Approximately 60% of the buffalo herds in South America are located in northern Brazil. However, compared with the research on cattle, research on buffaloes has been neglected.

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To evaluate the prevalence and possible risk factors for brucellosis caused by Brucella abortus in water buffaloes in the state of Pará, Brazil, 3,917 female buffalo serum samples from pregnant and non-pregnant animals were examined: 2,809 from Marajó Island and 1,108 from the mainland. The buffered acidified plate antigen (BAPA) screening test positively diagnosed 4.8% (188/3,917) of the animals with brucellosis, and the 2-mercaptoethanol (2-ME) confirmatory test affirmed 95.

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Bovine babesiosis is a tick-borne disease caused mainly by Babesia bovis and Babesia bigemina, which are associated to considerable economic losses in cattle herds worldwide. Approximately 60% of buffalo herds in South America are located in Northern Brazil. Little is known about the impact of babesiosis on buffalo herds in Brazil.

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The purpose of this study was to identify the influence of physiological state, season, breed, number of lactations, dairy productivity, and stocking rate on infestation by Rhipicephalus microplus in dairy cows. Two hundred cows were selected through proportional representative sampling at the Seropédica Experimental Station (Pesagro-Rio), Brazil. Fully or partially engorged R.

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This study aimed to investigate the frequency of homologous antibodies of IgG class against Borrelia burgdorferi in buffaloes in the state of Pará, Brazil. Blood serum samples from 491 buffaloes were analyzed by means of the indirect ELISA test, using crude antigen produced from a cultivar of the North American strain G39/40 of B. burgdorferi.

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