Interspecies interactions and potential Influenza A virus risk in small swine farms in Peru

Sarah Mccune,Joel M Montgomery,Vitaliano A Cama,Carmen S Arriola,Viterbo Ayvar,Armando E Gonzales,Robert H Gilman,Martín A Romero,Angela M Bayer

doi:10.1186/1471-2334-12-58

Abstract

BackgroundThe recent avian influenza epidemic in Asia and the H1N1 pandemic demonstrated that influenza A viruses pose a threat to global public health. The animal origins of the viruses confirmed the potential for interspecies transmission. Swine are hypothesized to be prime "mixing vessels" due to the dual receptivity of their trachea to human and avian strains. Additionally, avian and human influenza viruses have previously been isolated in swine. Therefore, understanding interspecies contact on smallholder swine farms and its potential role in the transmission of pathogens such as influenza virus is very important.MethodsThis qualitative study aimed to determine swine-associated interspecies contacts in two coastal areas of Peru. Direct observations were conducted at both small-scale confined and low-investment swine farms (n = 36) and in open areas where swine freely range during the day (n = 4). Interviews were also conducted with key stakeholders in swine farming.ResultsIn both locations, the intermingling of swine and domestic birds was common. An unexpected contact with avian species was that swine were fed poultry mortality in 6/20 of the farms in Chancay. Human-swine contacts were common, with a higher frequency on the confined farms. Mixed farming of swine with chickens or ducks was observed in 36% of all farms. Human-avian interactions were less frequent overall. Use of adequate biosecurity and hygiene practices by farmers was suboptimal at both locations.ConclusionsClose human-animal interaction, frequent interspecies contacts and suboptimal biosecurity and hygiene practices pose significant risks of interspecies influenza virus transmission. Farmers in small-scale swine production systems constitute a high-risk population and need to be recognized as key in preventing interspecies pathogen transfer. A two-pronged prevention approach, which offers educational activities for swine farmers about sound hygiene and biosecurity practices and guidelines and education for poultry farmers about alternative approaches for processing poultry mortality, is recommended. Virological and serological surveillance for influenza viruses will also be critical for these human and animal populations.

Highlights

The recent avian influenza epidemic in Asia and the H1N1 pandemic demonstrated that influenza A viruses pose a threat to global public health
The animal origin of the viruses highlighted the potential for interspecies transmission that may lead to viral reassortment
An unexpected contact with avian species was that swine were fed poultry mortality in 6/20 of the farms in Chancay, either raw (n = 3, Figure 1) or cooked (n = 3, Figure 2)

Summary

Introduction

The recent avian influenza epidemic in Asia and the H1N1 pandemic demonstrated that influenza A viruses pose a threat to global public health. Understanding interspecies contact on smallholder swine farms and its potential role in the transmission of pathogens such as influenza virus is very important. The recent epidemic of highly pathogenic avian influenza (HPAI) in Asia and the 2009 pandemic of so-called “Swine flu” (H1N1) demonstrated that influenza A viruses (IAVs) continue to pose a critical threat to global public health. The animal origin of the viruses highlighted the potential for interspecies transmission that may lead to viral reassortment. The transmission route of IAVs in aquatic birds is fecal-oral, and feces can contain highly concentrated amounts of the virus [3,4]. There are several examples of the infection of dogs by H3N2 [8,9,10], an example from Cambodia of the probable infection of five cat species by H5N1 [11], and isolation of the H5N2 virus in pigs in Korea [12]

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