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- A Nationwide Seroepidemiologic Study on Q Fever Antibodies in Sheep of PortugalPublication . Cruz, Rita; Esteves, Fernando; Nóbrega, Carmen; Santos, Carla; Ferreira, Ana S.; Mega, Cristina; Coelho, Ana C.; Vala, Helena; Mesquita, JoãoIntroduction: Q fever is an almost global zoonotic disease caused by Coxiella burnetii. Human infections can produce acute and chronic disease that can lead to abortions and stillbirths in pregnant women, usually infected by the inhalation of C. burnetii-contaminated aerosols or through consumption of contaminated products. Sheep are one of the primary animal reservoirs with disease being associated with vast shedding of bacteria in placentas, feces, milk, and birth fluids. Although almost neglected in the past, recent outbreaks of sheep origin have alerted the public and the scientific community. Materials and Methods: An epidemiologic survey to estimate the seroprevalence of Q fever antibodies was performed in a representative number of sheep of all regions of continental Portugal (n = 1068), using a commercial ELISA (ID Screen Q Fever Indirect Multi-species Kit; IDvet, Montpellier, France). Results and Discussion: An anti-C. burnetii seroprevalence of 11.4% (95% confidence interval 9.6–13.5) was found, with a clear distinction between the Center region with highest seroprevalence, and the rest of the territory. Sheep traditional farming is widely present in Portugal and is part of the cultural and gastronomical background of the country. This close proximity to small ruminants may contribute to the zoonotic transfer to humans.
- Crimean-Congo hemorrhagic fever virus circulating among sheep of Portugal: a nationwide serosurvey assessmentPublication . Mesquita, João; Cruz, Rita; Esteves, Fernando; Santos, Carla; Pousa, Humberto; Coelho, Catarina; Mega, Cristina; Nóbrega, Carmen; Vala, Helena; Peyrefitte, Christophe Nicolas; Nascimento, Maria São José; Barradas, Patrícia FerreiraCrimean-Congo hemorrhagic fever virus (CCHFV) is a widespread zoonotic pathogen that can cause mild to severe hemorrhagic disease in humans. CCHFV may be transmitted through direct contact with tissue or blood of viremic animals; however, the primary transmission route is through infected tick bites. CCHFV RNA has been detected in ticks feeding on domestic and wild animals in western Spain, suggesting an established circulation of CCHFV in Western Europe. Ruminants have been recognized as important CCHFV reservoirs and have been linked to human cases in endemic regions. Given the emergence of CCHF in neighboring Spain, and a report of two CCHFV seropositive humans in southern Portugal in 1985, we investigated the potential circulation of this virus in the country by performing a nationwide anti-CCHFV IgG serosurvey in sentinel sheep of Portugal. Sera (n = 459) randomly selected from widely distributed farms (n = 20) of Portugal were tested using a commercial double-antigen enzyme-linked immunosorbent assay, yielding an overall seroprevalence of 0.4% (95% confidence interval [CI] 0.04-1.56%). Positive sheep were from the southern region of Portugal (Alentejo region), which raise the seroprevalence of this region to 0.74% (95% CI 0.09-2.66%). This is the first study reporting the presence of CCHFV antibodies in sheep of Portugal, thus suggesting a geographical expansion of CCHFV to this country. It seems likely that CCHFV may exist focally in southern Portugal.
- Bulk-Tank Milk Longitudinal Serosurvey Reveals Decreasing Schmallenberg Virus Circulation in a Confined Population of Portuguese SheepPublication . Esteves, Fernando; Cruz, Rita; Nóbrega, Carmen; Santos, Carla; Ferreira, Ana S.; Petrovic, Tamas; Cardoso, Luís; Vala, Helena; Nascimento, Maria S.J.; Mesquita, João R.Introduction: In 2011, Schmallenberg virus (SBV) was first detected in dairy cattle herds in The Netherlands and Germany having since then spread across Europe. Today studies are starting to show a decrease in new SBV infections, a circumstance that raises alerts for possible re-emergence if ideal conditions for vector development occur. To assess the potential decrease in SBV circulation, we performed a 2-year longitudinal serological investigation for SBV infection at the herd level by using bulk-tank milk of a specific sheep breed from central Portugal. Materials and Methods: Bulk-tank milk samples from 68 flocks were collected in both 2015 and 2016, and lactosera were tested for IgG anti-SBV by EIA. Results and Discussion: Results show that in 2015, 92.6% (95% confidence interval [CI]: 83.9–96.8) of the bulk-tank milk samples were positive, whereas in 2016 only 77.9% (95% CI: 66.7–86.1 of the samples from the same flocks were positive. Differences in the 2015/2016 seroprevalences showed to be statistically significant (p = 0.027). This significant decrease at the herd level seems to be in agreement with reported data from other European countries and raise alerts, since increasingly favorable conditions (higher number of susceptible animals) are now present, potentially favoring SBV epidemics if improved conditions for midge replication occur in the future.
- Serological Evidence for Schmallenberg Virus Infection in Sheep of Portugal, 2014Publication . Esteves, Fernando; Mesquita, João; Vala, Helena; Abreu-Silva, Joana; van der Poel, Wim H M; Nascimento, Maria S JBetween November and December of 2014, a serosurvey was set up to evaluate the presence of Schmallenberg virus (SBV) antibodies in sheep of Portugal. Sera (n = 1068) were tested using an indirect enzyme linked immunosorbent assay (ID Screen(®) Schmallenberg virus indirect, IDvet Innovative Diagnostics, Montpellier, France). The estimated occurrence of immunogobulin G (IgG) antibodies against SBV in sheep of Portugal was 12.8% (95% confidence interval 11.0-15.0%). This is the first study reporting the presence of SBV antibodies in sheep of Portugal.