Vaccinia virus in Feces and Urine of Wild Rodents from São Paulo State, Brazil

Abstract

The origin of Vaccinia virus (VACV) outbreaks in Brazil remains unknown, but since the isolation of VACV in Mus musculus mice during a zoonotic outbreak affecting cattle and milkers, peridomestic rodents have been suggested to be a link between cows and wild animals. Considering that experimentally infected mice eliminate viral particles in their feces, we investigated the presence of VACV in the feces and urine of wild rodents that were captured in the forest areas surrounding milking farms in the central west region of São Paulo State. For the first time, this work reports the detection of VACV by PCR in the feces of naturally infected Oligoryzomys flavescens, Oligoryzomys nigripes, and Sooretamys angouya, and in the urine of Oligorizomys flavescens, which raises important questions about the spread of VACV by rodent feces and its potential to induce clinical infections in cows.

Vaccinia Virus among Domestic Dogs and Wild Coatis, Brazil, 2013–2015

“…The most affected hosts during outbreaks are dairy cattle and humans ( 2 ). Recent studies assessing the role of wildlife in the maintenance cycle of VACV in nature have corroborated previous findings that rodents and marsupials serve as links between natural and anthropic environments ( 2 – 4 ).…”

Vaccinia Virus in Blood Samples of Humans, Domestic and Wild Mammals in Brazil

“…However, VACV DNA was detected in the feces of O. flavescens , O. nigripes and S. angouya , as well as in urine of O. flavescens from the same area. The simultaneous detection of VACV DNA in feces and neutralizing antibodies in serum samples of two O. flavescens from Bofete were observed (unpublished work [ 18 , 26 ]). These animals were apparently healthy, and showed 54% and 59% of reduction in viral plaques being considered positives to OPV antibodies [ 18 ].…”

“…On the other hand, this county showed the greatest proportion of seropositivity for cows (39%) and horses (22%), while 10% opossum were seropositive and all wild rodents were seronegative [ 18 ]. Comparatively, Bofete showed detection of viral DNA in blood samples of one cow and two D. aurita , and in feces of two O. flavescens and one O. nigripes (unpublished work [ 26 ]). Bofete also showed the second highest seropositive rate of cows (14%) and horses (9%), 9% of opossums ( D. albiventris and D. aurita ) seropositive, and the highest seropositive rate in wild rodents (11%) [ 18 ].…”

“…Bofete also showed the second highest seropositive rate of cows (14%) and horses (9%), 9% of opossums ( D. albiventris and D. aurita ) seropositive, and the highest seropositive rate in wild rodents (11%) [ 18 ]. In contrast, in Anhembi, VACV DNA in blood samples were detected in three cows, one horse and one D. albiventris, while viral DNA were detected in feces samples from one O. nigripes and two S. angouya and in urine samples from one O. flavescens (unpublished work [ 26 ]). In addition, Anhembi showed the lowest seropositive rate in cows (5%) and horses (3%), and opossums (6.5%) and the second highest rate in wild rodents, with 9% of seropositivity [ 18 ].…”

“…In addition, this suggests the existence of a viral spread by contiguity, from Torre de Pedra to Bofete to Anhembi. It is possible that this viral circulation occurs in opossums and wild rodents, and these last animals eliminate low viral loads in their feces and urine (unpublished work [ 26 ]) contaminating the environment. The low viral loads in the environment can induce subclinical infections, which is evidenced by presence of viral DNA and neutralizing antibodies in blood of domestic and wild animals that are apparently healthy.…”