Vaccinia virus: shedding and horizontal transmission in a murine model (original) (raw)
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Short Communication Vaccinia virus: shedding and horizontal transmission in a murine model
2000
Vaccinia virus (VACV) has been associated with several bovine vaccinia outbreaks in Brazil, affecting cattle and humans. There are no available data about VACV environmental circulation or the role of wildlife in the emergence of an outbreak. Since VACV was isolated from rodents in Brazil, we investigated shedding and transmission of VACV strains in mice. The VACV excretion profile was assessed by PCR and chicken chorioallantoic membrane infection, revealing viral DNA and infectious virus in the faeces and urine of intranasally infected mice. Horizontal transmission was assessed by exposure of sentinel mice to wood shavings contaminated with excrement, to mimic a natural infection. Sentinel mice showed orthopoxvirus antibodies, and VACV DNA and infectious virus were detected in their faeces and intestines, even after six rounds of natural transmission. Together, these data suggest that murine excrement could play a relevant role in VACV spread and transmission, perhaps helping to explain how these viruses circulate between their natural hosts.
VACV shedding and horizontal transmission in a murine model
2013
Vaccinia virus (VACV) has been associated with several bovine vaccinia outbreaks in Brazil, affecting cattle and humans. There are no available data about VACV environmental circulation or the role of wildlife in the emergence of an outbreak. Since VACV was isolated from rodents in Brazil, we investigated shedding and transmission of VACV strains in mice. The VACV excretion profile was assessed by PCR and chicken chorioallantoic membrane infection, revealing viral DNA and infectious virus in the faeces and urine of intranasally infected mice. Horizontal transmission was assessed by exposure of sentinel mice to wood shavings contaminated with excrement, to mimic a natural infection. Sentinel mice showed orthopoxvirus antibodies, and VACV DNA and infectious virus were detected in their faeces and intestines, even after six rounds of natural transmission. Together, these data suggest that murine excrement could play a relevant role in VACV spread and transmission, perhaps helping to explain how these viruses circulate between their natural hosts.
Vector-Borne and Zoonotic Diseases, 2012
Vaccinia virus (VACV) has been associated with several exanthematic outbreaks in bovine, human, and equine species in Brazilian rural areas. Little is known about VACV reservoirs, although it is believed that rodents could be associated with VACV outbreaks. With the goal of filling one more gap in the VACV ecological puzzle, the present work aimed at mimicking a potential transmission route of VACV between cows and rodents, both known as natural VACV hosts. Balb/c mice were exposed to feces of experimentally VACV infected cows for 20 days, and samples from these mice were examined by using molecular and serological tests. VACV DNA was detected in feces and blood samples after several days of exposure; infectious VACV particles were also detected in the feces. The presence of anti-VACV neutralizing antibodies in murine sera further suggested horizontal transmission. If the transmission model described here can be applied to natural environments, exposure to bovine feces could be considered a risk factor for the spread of VACV; consequently, the traditional use of bovine manure as a fertilizer in agricultural activities may be promoting the infection of rodents.
Vaccinia virus in Feces and Urine of Wild Rodents from São Paulo State, Brazil
Viruses, 2018
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.
Emerging infectious diseases, 2017
Vaccinia virus (VACV) is a zoonotic agent that causes a disease called bovine vaccinia, which is detected mainly in milking cattle and humans in close contact with these animals. Even though many aspects of VACV infection have been described, much is still unknown about its circulation in the environment and its natural hosts/reservoirs. To investigate the presence of Orthopoxvirus antibodies or VACV DNA, we captured small rodents and marsupials in 3 areas of Minas Gerais state, Brazil, and tested their samples in a laboratory. A total of 336 animals were tested; positivity ranged from 18.1% to 25.5% in the 3 studied regions located in different biomes, including the Atlantic Forest and the Cerrado. Analysis of nucleotide sequences indicated co-circulation of VACV groups I and II. Our findings reinforce the possible role played by rodents and marsupials in VACV maintenance and its transmission chain.
Archives of Virology, 2013
Vaccinia virus (VACV), the etiological agent of an exanthematic disease, has been associated with several bovine outbreaks in Brazil since the end of the global vaccination campaign against smallpox. It was previously believed that the vaccine virus used for the WHO global campaign had adapted to an unknown wild reservoir and was sporadically re-emerging in outbreaks in cattle and milkers. At present, it is known that Brazilian VACV is phylogenetically different from the vaccinia virus vaccinal strain, but its origin remains unknown. This study assessed the seroprevalence of orthopoxviruses in domestic and wild animals and farmers from 47 farms in three cities in the southwest region of the state of São Paulo with or without official reports of outbreaks in cattle or humans. Our data indicate a low seroprevalence of antibodies in wild animals and raise interesting questions about the real potential of wild rodents and marsupials as VACV reservoirs, suggesting other routes through which VACV can be spread.
Alternative Routes of Zoonotic Vaccinia Virus Transmission, Brazil
Emerging Infectious Diseases, 2015
To the Editor: Vaccinia virus (VACV) causes exanthematous disease (bovine vaccinia) in Brazil. Outbreaks of this disease in humans have been reported since the late 1990s and have spread throughout Brazil (1). Natural human infections with VACV occur by close contact with infected cattle during milking. Lesions can spread to secondary body sites (forearms, arms, and face). Thus, personto-person transmission occurs (1). Moreover, virus can persist in household environments, remain infectious, and be transmitted by fomites (2). Although raw milk and cheese are potential sources of infection, no clinical cases have been associated with this transmission route (3,4). Data for person-to-person transmission in Brazil are scarce, but person-to-person transmission was recently reported (5). We report a possible case of person-to-person transmission of VACV.
Vaccinia Virus in Blood Samples of Humans, Domestic and Wild Mammals in Brazil
Viruses, 2018
Outbreaks of Vaccinia virus (VACV) affecting cattle and humans have been reported in Brazil in the last 15 years, but the origin of outbreaks remains unknown. Although VACV DNA have been already detected in mice (Mus musculus), opossums (Didelphis albiventris) and dogs during VACV zoonotic outbreaks, no transmission to cattle or humans from any of these were reported during Brazilian outbreaks. In this work, we assessed the PCR positivity to VACV in blood samples of cows and other domestic mammals, wild rodents and other wild mammals, and humans from areas with or without VACV infection reports. Our results show the detection of VACV DNA in blood samples of cows, horse and opossums, raising important questions about VACV spread.
Vaccinia Virus Natural Infections in Brazil: The Good, the Bad, and the Ugly
Viruses, 2017
The orthopoxviruses (OPV) comprise several emerging viruses with great importance to human and veterinary medicine, including vaccinia virus (VACV), which causes outbreaks of bovine vaccinia (BV) in South America. Historically, VACV is the most comprehensively studied virus, however, its origin and natural hosts remain unknown. VACV was the primary component of the smallpox vaccine, largely used during the smallpox eradication campaign. After smallpox was declared eradicated, the vaccination that conferred immunity to OPV was discontinued, favoring a new contingent of susceptible individuals to OPV. VACV infections occur naturally after direct contact with infected dairy cattle, in recently vaccinated individuals, or through alternative routes of exposure. In Brazil, VACV outbreaks are frequently reported in rural areas, affecting mainly farm animals and humans. Recent studies have shown the role of wildlife in the VACV transmission chain, exploring the role of wild rodents as reser...
American Journal of Tropical Medicine and Hygiene, 2014
Bovine vaccinia (BV) is an emerging zoonosis caused by the Vaccinia virus (VACV), genus Orthopoxvirus (OPV), Poxviridae family. In general, human cases are related to direct contact with sick cattle but there is a lack of information about human-to-human transmission of VACV during BV outbreaks. In this study, we epidemiologically and molecularly show a case of VACV transmission between humans in Sã o Francisco de Itabapoana County, Rio de Janeiro state. Our group collected samples from the patients, a 49-year-old patient and his son. Our results showed that patients had developed anti-OPV IgG or IgM antibodies and presented neutralizing antibodies against OPV. The VACV isolates displayed high identity (99.9%) and were grouped in the same phylogenetic tree branch. Our data indicate that human-to-human VACV transmission occurred during a BV outbreak, raising new questions about the risk factors of the VACV transmission chain.