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- Rickettsia massiliae circulation in sheep and attached Rhipicephalus sanguineus in Central PortugalPublication . Mesquita, João R.; Santos-Silva, Sérgio; de Sousa Moreira, Alícia; Baptista, Maria Beatriz; Cruz, Rita; Esteves, Fernando; Vala, Helena; Barradas, Patrícia F.Rickettsiosis is considered an emerging/re-emerging vector-borne disease that causes signifcant public health threats. Ticks are reservoirs and vectors of Rickettsia having a signifcant role in the transmission of rickettsiae. In Portugal, little is known about tick-borne Rickettsia species in sheep. Therefore, this study aimed to investigate rickettsiae infection in ticks and their sheep host from 27 farms in four districts of central Portugal, to clarify the role of the sheep host in the circulation of this zoonotic agent. Between March and May 2021, EDTA blood samples (n=100) of healthy grazing sheep and their ticks (n=100, one tick per animal) were collected during a herd health program in central Portugal. Obtained ticks were identifed as Rhipicephalus sanguineus sensu lato by PCR targeting a partial sequence of 16S rRNA gene followed by sequence analysis. Rhipicephalus sanguineus s.l. and host sheep blood were tested for the presence of Rickettsia spp. by PCR targeting a partial sequence of ompB and ompA genes. From a total of 100 paired R. sanguineus s.l. and host sheep, Rickettsia massiliae was detected in 62 ticks and 35 grazing sheep blood samples, collected in central Portugal, 2021. All 35 positive sheep had attached positive R. sanguineus s.l., with matching nucleotidic sequences. These fndings suggest that sheep may develop rickettsiemia and are likely capable of transmitting and amplifying the infection to uninfected ticks maintaining rickettsiae in circulation in the domestic cycle.
- Molecular evidence of sporadic Coxiella burnetii excretion in sheep milk, central PortugalPublication . Pires, Humberto; Santos-Silva, Sérgio; Cruz, Andreia V.S.; Cardoso, Luís; Lopes, Ana Patrícia; Pereira, Maria; Nóbrega, Carmen; Mega, Cristina; Santos, Carla; Cruz, Rita; Esteves, Fernando; Vala, Helena; Matos, Ana Cristina; Barradas, Patrícia F.; Coelho, Ana Cláudia; Mesquita, João R.Coxiella burnetii is the etiologic agent of Q fever, a worldwide zoonosis. Cattle, sheep and goats are considered the main reservoirs of the disease. Transmission to humans occurs mainly through the inhalation of infectious aerosols from milk, faeces, urine, and birth products from infected ruminants. In this study, a 2-year longitudinal approach was performed to ascertain the excretion of C. burnetii in bulk tank milk samples of sheep from a mountain plateau in central Portugal, with sampling conducted during the years 2015 and 2016. From a total of 156 bulk tank milk samples tested by qPCR, only one showed to be positive for C. burnetii (1.28% [95%CI: 0.03–6.94]), from 2015, the first year of collection. Bidirectional sequencing and phylogenetic analysis of IS1111 transposase partial region confirmed the presence of C. burnetii DNA. The presence of C. burnetii in raw milk samples highlights the necessity for additional research to determine if raw milk is a potential source for human infection. Animal health surveillance and prevention measures against this zoonotic disease should be considered.