Parasitological and clinical-pathological findings in twelve outbreaks of acute trypanosomiasis in dairy cattle in Rio de Janeiro state, Brazil.

In Brazil, infection in cattle was first reported in the state of Pará, in 1944, and the presence of the parasite has already been recorded in several states. The purpose of this study was to report the clinical-pathological aspects of a natural infection by T. vivax in dairy cattle in the state of Rio de Janeiro. Twelve outbreaks of the infection were diagnosed in 11 municipalities from April 2016 to October 2018. All properties had acquired cattle from states where the disease had already been recorded and it was found that needles for oxytocin administration had been shared. These outbreaks were studied by visiting the properties to perform anamnesis, clinical exams and collection of material for laboratory diagnosis. Laboratory diagnosis was performed through parasitological, molecular and histopathological techniques. Animals with confirmed diagnosis for T. vivax showed anemia, lack of appetite, decreased milk production, weight loss, weakness, abortion, diarrhea and neurological signs. The main histological lesions found were meningoencephalitis and lymphohistiocytic myocarditis. In the central nervous system, the lesions were more severe in the brain compared to the spinal cord, being progressively more severe in the rostro-dorsal direction. Also, they were more accentuated in the white matter compared to the gray matter. Due to nonspecific clinical signs, laboratory tests were key for diagnosis. Trypanosomiasis in cattle herds in the state of Rio de Janeiro, Brazil, is of great concern because of its potential to cause economic losses.

Molecular epidemiology of the emerging zoonosis agent Anaplasma phagocytophilum (Foggie, 1949) in dogs and ixodid ticks in Brazil.

BACKGROUND: Anaplasma phagocytophilum is an emerging pathogen of humans, dogs and other animals, and it is transmitted by ixodid ticks. The objective of the current study was a) detect A. phagocytophilum in dogs and ixodid ticks using real-time Polymerase Chain Reaction (qPCR); and b) Determine important variables associated to host, environment and potential tick vectors that are related to the presence of A. phagocytophilum in dogs domiciled in Rio de Janeiro, Brazil. METHODS: We tested blood samples from 398 dogs and samples from 235 ticks, including 194 Rhipicephalus sanguineus sensu lato, 15 Amblyomma cajennense, 8 Amblyomma ovale and 18 pools of Amblyomma sp. nymphs. A semi-structured questionnaire was applied by interviewing each dog owner. Deoxyribonucleic acid obtained from ticks and dog buffy coat samples were amplified by qPCR (msp2 gene). The sequencing of 16S rRNA and groESL heat shock operon genes and a phylogenetic analysis was performed. The multiple logistic regression model was created as a function of testing positive dogs for A. phagocytophilum. RESULTS: Among the 398 blood samples from dogs, 6.03% were positive for A. phagocytophilum. Anaplasma phagocytophilum was detected in one A. cajennense female tick and in five R. sanguineus sensu lato ticks (four males and one female). The partial sequences of the 16S rRNA, and groESL genes obtained were highly similar to strains of A. phagocytophilum isolated from wild birds from Brazil and human pathogenic strains. The tick species collected in positive dogs were R. sanguineus sensu lato and A. cajennense, with A.cajennense being predominant. Tick infestation history (OR = 2.86, CI = 1.98-14.87), dog size (OR = 2.41, IC: 1.51-12.67), the access to forest areas (OR = 3:51, CI: 1.52-16.32), hygiene conditions of the environment in which the dogs lived (OR = 4.35, CI: 1.86-18.63) and Amblyomma sp. infestation (OR = 6.12; CI: 2.11-28.15) were associated with A. phagocytophilum infection in dogs. CONCLUSIONS: This is the first report of A. phagocytophilum in ixodid ticks from Brazil. The detection of A. phagocitophylum in A. cajennense, an aggressive feeder on a wide variety of hosts, including humans, is considered a public health concern.

Detection of Anaplasma phagocytophilum in Brazilian dogs by real-time polymerase chain reaction.

Anaplasma phagocytophilum was detected in dogs from Brazil in the municipalities of Seropédica and Itaguaí, Rio de Janeiro state, by real-time polymerase chain reaction (PCR) using SYBR Green to detect the amplification. Of 253 samples, 18 (7.11%) were positive, with a threshold cycle (Ct) ranging from 31 to 35 cycles. The PCR product from a positive sample was cloned and sequenced. The sequence obtained demonstrated 100% identity with other A. phagocytophilum sequences published in the GenBank database. The analytical sensitivity of RT-PCR using SYBR Green system was able to detect 3 plasmid copies when defined numbers of plasmid copies containing 122 base pairs from the msp2 gene were used. The assay was considered specific when DNA from bacteria (Anaplasma platys, Anaplasma marginale, Ehrlichia canis, Neorickettsia risticii, Rickettsia rickettsii) closely related to A. phagocytophilum was placed in the reaction. These results demonstrate that the canine granulocytic anaplasmosis agent is present in regions in which dogs could be a source of infection for tick vectors. The current study reports the detection of A. phagocytophilum, a zoonotic agent responsible for Human granulocytic anaplasmosis, in Brazilian dogs.