Outbreaks of vesicular disease caused by Vaccinia virus in dairy cattle from Goiás State, Brazil (2010-2012)

Abstract

Pesq. Vet. Bras. 33 (7) Midwestern Brazil (2010, involving a total of 122 cows, 12 calves and 11 people. Dairy cows (3 to 9 years old) were affected in all cases and calves (2 to 9 months old) were affected in five outbreaks, presenting oral lesions. The morbidity ranged between 8 and 100% in cows, and 1.5 to 31% in calves. In the cows, the clinical signs started with vesicles (2-7mm), painful and coalescent papules (3-8 mm), which resulted in ulcers (5-25mm) and scabs in teats, and, occasionally, in the muzzle. The clinical course lasted from 16 to 26 days. The histopathology of bovine skin samples revealed superficial perivascular inflammatory infiltrate of lymphocytes, plasma cells, neutrophils, macrophages and multifocal areas of acanthosis, spongiosis, hipergranulosis and parakeratotic or orthokeratotic hyperkeratosis with adjacent focally extensive ulcers. Eosinophilic inclusion bodies were noted in the cytoplasm of the keratinocytes. PCR to vgf gene of Orthopoxvirus was positive in samples collected from all outbreaks, and in some cases, genomic VACV sequences were identified by nucleotide sequencing of the PCR amplicons. Infectious virus was isolated in cell culture from scabs from one outbreak. Antibodies to Orthopoxvirus were detected in at least 3 or 4 animals in most outbreaks, by ELISA (outbreaks 1, 2, 3, 4, 5 and 7) or virus-neutralization (outbreak 6). Neutralizing titers ranging from 8 to 64 in outbreak 6. In all outbreaks, VACV infection was suspected based on the clinical and pathological findings and it was confirmed by laboratory tests. Upon the etiological confirmation, other agents associated with vesicular disease were discarded. In all outbreaks, at least one milker who handled the affected cows developed malaise, headache, fever, painful vesico-pustular lesions mainly in the hands, but also in the neck and nose. These results confirm the circulation of VACV in the region and call attention for a correct diagnosis and the adoption of prophylactic and control measures.

Vaccinia Virus Natural Infections in Brazil: The Good, the Bad, and the Ugly

“…The circulation of zoonotic VACV was first reported in Southeast Brazil in 1999 [ 35 , 36 ]. The infection was associated with several exanthematous outbreaks that have been described in Brazilian rural areas affecting mainly milking cattle and their handlers [ 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 ]. In Brazil, the disease caused by VACV is popularly known as “bovine vaccinia” (BV), probably due to the fact that most cases have been described in dairy cattle.…”

Swinepox dermatitis in backyard pigs in Northeastern Brazil

“…With smallpox eradication and the end of vaccination, the possibility of cases in pigs associated with escape of vaccine virus virtually disappeared (Roehe & Brito 2012). Nonetheless, VACV infection has been repeatedly reported in several Brazilian states affecting mainly dairy cattle and man (Damaso et al 2000, Silva--Fernandes et al 2009, Sant' Ana et al 2013) but also other species such as horses (Brum et al 2010, Campos et al 2011, wild rodents and primates (Abrahão et al 2010b). Thus, VACV should be included in the differential diagnosis of vesicular cutaneous diseases in swine since the lesions caused by SWPV and VACV are virtually identical.…”

Vaccinia virusdetection in dairy products made with milk from experimentally infected cows

“…Vaccinia virus (VACV) is included among these microorganisms, as it has been detected in the milk of naturally infected cows (Abrahão, Oliveira et al., ). VACV is the agent of bovine vaccinia (BV) in Brazil, an emerging zoonosis that causes exanthematic lesions on the teats of dairy cows and on the hands of milkers (Damaso, Esposito, Condit, & Moussatché, ; De Souza Trindade et al., ; Leite et al., ; Lobato et al., ; Nagasse‐Sugahara et al., ; Sant'Ana et al., ; Trindade et al., ).…”