Vaccinia virus: transmissão vertical e pelo leite em modelo murino

Abstract

Poxviridae contains the largest known animal viruses that infect vertebrate and invertebrate hosts. Vaccinia virus (VACV) belongs to the genus (OPV) Orthopoxvirus and is the prototype of the family, being used as attenuated virus vaccine during the smallpox eradication campaign, coordinated by the World Health Organization (WHO). Bovine vaccinia (VB) is an emerging and exanthematic outbreak that occurred frequently in the last 10 years in Brazil affecting cows and milkers and causing economic losses and problems related to public health in various regions of the country. There are few studies about vertical transmission of VACV and about the pathogenesis and immunological reactions of VACV infections during pregnancy and lack of knowledge about the potential viral transmission through contaminated milk. Therefore, the objective was to evaluate the vertical and milk transmission of brazilian Vaccinia virus (Br- VACV), in pregnant and lactating mice model. Pregnant, non pregnant and lactating Balb/c mice were inoculated intranasally with GP2V and clinical signs, viral DNA detection and neutralizing antibodies to VACV were evaluated. The results showed that the mice did not show morbidity or mortality after infection with GP2V. Viral DNA was detected in fetuses and neonate born mice infected with GP2V as well as females infected during the lactation period, confirming VACV transmission from mother to child in a murine model. Detection of DNA in placenta and fetus obtained from post mortem cesarean indicated vertical transmission in mice. Advances were obtained in the elucidation of factors involved in the establishment of outbreaks of VB in Brazil, as the origin of VACV their natural reservoirs, and the mechanisms by which the virus persists in nature.