Outbreak of Bluetongue virus serotype 4 in dairy sheep in Rio de Janeiro, Brazil

Abstract

Abstract. In late January 2013, 10 nonpregnant Lacaune dairy ewes raised under extensive husbandry management on a farm in Rio de Janeiro, Brazil, presented with the general clinical signs of lethargy, hyporexia, edema of the face, hyperemia of the exposed parts of the skin, mouth lesions, pyrexia, and lameness. Additionally, 2 pregnant ewes died suddenly after the onset of respiratory signs. The complete blood counts and biochemistry analyses showed neutrophilic leukocytosis with monocytosis and reactive lymphocytes, normocytic normochromic anemia and increased aspartate aminotransferase levels. Postmortem examination revealed erosions on the lingual mucosa, bilateral submandibular ganglia infarctions, yellow foamy fluid accumulation in the trachea and bronchial bifurcation, pulmonary congestion, and edema associated with hemorrhagic lesions on the pulmonary artery and heart. The clinical and pathological findings were suggestive of bluetongue. For a molecular and virological diagnosis, tissue samples were analyzed by Bluetongue virus-specific real-time reverse transcription polymerase chain reaction (qRT-PCR), and viral isolation was performed in embryonated chicken eggs. For viral typing, positive tissue and egg-isolated samples were analyzed by qRT-PCR using primers and probes specific for the structural VP2 gene in genome segment 2 of all 26 serotypes. There are still no contingency plans for responding to an outbreak of bluetongue disease in Brazil, and this episode emphasizes the need for continuing serological and entomological surveillance programs. Additionally, this report describes the isolation of Bluetongue virus serotype 4 in sheep in the Americas.

Experiences from the 2014 outbreak of bluetongue in Greece

“…Clinical anaemia had rarely been reported as associated with the disease. In the past, only Balaro et al (2014) have reported this finding in cases of the disease caused by serotype 4 of the virus. In fact, Dercksen and Lewis (2007) have described that absence of anaemia can be used diagnostically for clinical differentiation of bluetongue from other diseases manifested with oedema in the head, e.g., H. contortus or F. hepatica infections.…”

Prevalence and risk factors for bluetongue in the State of São Paulo, Brazil

“…In 2011 and 2013, recurrent outbreaks of BT were reported in sheep in the State of Rio de Janeiro, where BTV‐4 serotype was identified (Balaro et al . ,b). In this study, specific antibodies against BTV‐1, 4 and 17 were detected.…”

Isolation and evolutionary analysis of Australasian topotype of bluetongue virus serotype 4 from India

“…In the Americas, BTV‐4 was first reported from a quarantine station in Florida, USA, from Zebu cattle imported from Brazil in 1980 (Groocock & Campbell, ). Later, this serotype was isolated from Puerto Rico and the Dominican Republic in 1990, from Argentina in 1999‐2010 and from Brazil in 2014 (Balaro et al., ; Lager et al., ; Legisa, Gonzalez, De Stefano, Pereda, & Dus Santos, ; Legisa, Gonzalez, & Dus Santos, ; Mo et al., ). Serological survey of Central and South American countries also indicated the prevalence of antibodies against this serotype in some of the countries (Trinidad and Tobago, Barbados, Puerto Rico, Dominican Republic, Argentina, Brazil) in this region (Thompson, Mo, Oviedo, & Homan, ).…”

“…Puerto Rico and the Dominican Republic in 1990, from Argentina in 1999-2010and from Brazil in 2014(Balaro et al, 2014Lager et al, 2004;Legisa, Gonzalez, De Stefano, Pereda, & Dus Santos, 2013;Legisa, Gonzalez, & Dus Santos, 2014;Mo et al, 1994). Serological survey of Central and South American countries also indicated the prevalence of antibodies against this serotype in some of the countries (Trinidad and Tobago, Barbados, Puerto Rico, Dominican…”