Anti-influenza A virus antibodies in Tayassuidae from commercial rearing farms in Brazil Detecção de anticorpos contra vírus influenza A em Tayassuidae de criações comerciais no Brasil

Family Tayassuidae in the suborder Suina include two species of peccaries in Brazil: the white-lipped peccary (Tayassu pecari) and the collared peccary (Pecari tajacu). These animals share common pathogens with domestic swine (Sus scrofa); however, their role as potential carrier remains unclear. This study focused on detecting the prevalence of influenza A antibodies in Tayassu pecari and Pecari tajacu from commercial rearing farms from two states in Brazil. A set of 50 blood samples from Pecari tajacu and 55 from Tayassu pecari were analyzed using a commercial indirect ELISA in order to investigate anti influenza A antibodies. Pecari tajacu samples presented 22% (11/50) of seropositivity for the virus. Serological surveillance is an important tool to identify the presence and the spread of the influenza virus in feral pigs.

http://dx.doi.org/10.1590/0103-8478cr20180694 White-lipped peccary and collared peccary are species of feral pigs found in ecosystems from southern North America throughout South America (SICURO & OLIVEIRA 2002).Peccaries and pigs are able to be infected by several common pathogens, once they diverged one million years ago from a common ancestor (COUTINHO et al., 2012) and previous studies detected peccaries as potential reservoirs of infectious diseases for domestic pigs and wild swine (Sus scrofa) (HERRERA et al. 2008;COUTINHO et al. 2012).
Influenza is a major cause of acute respiratory disease outbreaks in domestic pigs, highly contagious, affecting pigs and other species, including humans.When first introduced in the farm, the disease was described as a sudden onset, involving a large number of pigs (up to 100%) of various age groups (VANALSTINE, 2012).Once established in the farm (endemic form), the disease usually appears in the nursery phase in unvaccinated herds, because maternal antibodies persist until the sixth week of life (JANKE, 2000).
ABSTRACT: Family Tayassuidae in the suborder Suina include two species of peccaries in Brazil: the white-lipped peccary (Tayassu pecari) and the collared peccary (Pecari tajacu).These animals share common pathogens with domestic swine (Sus scrofa); however, their role as potential carrier remains unclear.This study focused on detecting the prevalence of influenza A antibodies in Tayassu pecari and Pecari tajacu from commercial rearing farms from two states in Brazil.A set of 50 blood samples from Pecari tajacu and 55 from Tayassu pecari were analyzed using a commercial indirect ELISA in order to investigate anti influenza A antibodies.Pecari tajacu samples presented 22% (11/50) of seropositivity for the virus.Serological surveillance is an important tool to identify the presence and the spread of the influenza virus in feral pigs.Key words: influenza, antibodies, peccaries.

MICROBIOLOGY
surveillance in pigs has revealed that influenza virus transmission from humans to swine is far more frequent than swine-to-human zoonosis, and these events are the main source of new viral diversity (NELSON & VINCENT, 2015).
Serological data from other countries in wild boars (Sus scrofa) and feral pigs identified antibodies to H3N2 and H1N1 (VICENTE et al., 2002).In Brazil, wild boars samples revealed a human-like H1N2 influenza virus, with genes derived from the H1N1 pdm09 (BIONDO et al., 2014).
The commercial swine herds are constantly investigated for influenza virus infection through passive monitoring, the same does not occur in wild boars and peccaries herds.In this scenario, the present study investigated evidence of antibodies against this virus in peccaries from commercial farms in Brazil.
In the present study blood samples were collected from adult slaughtered peccaries of semiintensive system farms from two Brazilian States, which produced only one of studied species; i.e., there was no farm with extensive mixing between the two species.A total of 105 animals were sampled, 55 samples of Tayassu pecari were obtained on the same day on November of 2014 and 50 samples of Pecari tajacu on the same day on February of 2015.Further information about the specific locations of the herds, number of herds, ages and weight of slaughtered peccaries and herd management were not provided by the farmers.
The epidemiology of influenza in pigs is a complex relationship between human, avian and swine viruses with putative genetic viral reassortments, which can create novel subtypes with pandemic potential for people and swine (VANALSTINE, 2012).
In Brazil, influenza virus infection of pigs has been suspected since the late 1930s, but the first isolation from pigs occurred in 1974 (CUNHA et al., 1978).The situation changed quickly after the emergence of H1N1 pdm09 in pigs in 2009 (SCHAEFER et al., 2011).
Since then, serological surveillance in commercial pigs became routine and Brazilian commercial herds have shown the wide circulation of this agent, presenting more than 70% of seroprevalence in almost 65% of tested herds (CIACCI-ZANELLA et al., 2015) and more than 40% of seropositive sows (RAJAO et al., 2013).
The semi-intensive system allows the circulation of peccaries to an open area, favoring the contact between wild boars and other animal species as avian and feral pigs beside the contact with humans, this situation brings a concern regarding the favorable conditions for virus infection or spreading and possibly an interspecies transmission as observed in previous studies between humans-wild boars (BIONDO et al., 2014) and humans-pigs (FORGIE et al., 2011).
In conclusion, the first detection of influenza antibodies in Pecari tajacu confirmed the virus circulation in this population, thus, from now on, the serological surveillance is required to monitor the circulation and further studies are required to understand the role of peccaries on the pathogen dissemination and on risks of reassortment events with pigs.