Sero-prevalence of Influenza a Antibodies in Pigs of Bhaktapur, Kavre and Banke Districts of Nepal

Abstract

Pigs play a key role in inter-species transmission of influenza virus, because they have receptors to both avian and human influenza viral strains. A study was conducted in three different districts namely Bhaktapur, Kavre and Banke with face to face type of questionnaire survey and serum sample collection. Indirect Enzyme Linked Immunoassay was utilized for the collected 231 samples for serologic evidence of influenza A. Of the total 231 samples tested, 11 were positive for Influenza virus A with an overall sero-prevalence of (4.76%; Cl95%: 2.68-8.324) Kavre district had highest (5.88%; Cl95%: 2.539-13.04) sero-prevalence, followed by Bhaktapur (5.13%; Cl95%: 2.012-12.46) and Banke (2.94%; Cl95%; 0.8104-10.1) with no significant difference (p=0.685). Rearing swine along with poultry was the most significant risk factor (p=0.03); all positive cases were from the farms that adopted integrated farming system with little to no bio-security measures, especially poultry and swine. Present finding depicts that Influenza A is prevalent in pig farms of Kavre, Banke and Bhaktapur. Further research is needed to sub-type the influenza virus and also determine the effect of commercial poultry and migratory birds on the outbreak of influenza A in swine. Int. J. Appl. Sci. Biotechnol. Vol 6(2): 122-126

A systematic review of influenza A virus prevalence and transmission dynamics in backyard swine populations globally

“…While IAV active infection was detected only in a few backyard swine in Asia (Cambodia and Indonesia) [ 32 , 36 ], seroprevalence was reported from Bangladesh [ 30 ], Bhutan [ 31 ], China [ 23 , 33 ], India [ 34 ], Indonesia [ 36 ], Nepal [ 37 ], and Viet Nam [ 39 ]. We believe this was due to the surveillance objectives, which varied between countries.…”

“…Total 68 sera samples were collected from free-range backyard swine and tested for IAV antibodies using ELISA assay. Only two sera samples were found positive for IAV antibodies [ 37 ].…”

“…10 a). Interestingly, 13 (38.24%) studies reported that swine and poultry regularly interacted in the backyards [ 12 , 20 , 23 , 27 , 28 , 33 , 35 , 37 , 39 , 40 , 47 – 49 ], while seven (20.58%) studies reported interactions among the wild birds, swine, and poultry [ 24 – 26 , 30 , 32 , 36 , 44 ]. Two (5.88%) studies reported interactions among the swine, poultry, and cattle [ 42 , 46 ], while the other remaining studies (n = 12; 35.29%) did not mention any interactions between backyard swine and other animal species [ 18 , 21 , 22 , 29 , 31 , 34 , 38 , 41 , 45 ] (Fig.…”

“…As far as the reports of interspecies IAV transmission were concerned, numerous studies suggested human-to-swine (reverse zoonotic) transmission of IAV (n = 15; 44.12%) [ 19 , 21 , 22 , 24 , 26 , 27 , 29 , 31 , 33 , 34 , 41 , 42 , 45 , 46 , 50 ] while swine-to-human (n = 2; 5.88%) [ 18 , 23 ], poultry-to-swine (n = 2; 5.88%) [ 36 , 40 ], and wild birds-to-swine (n = 1; 2.94%) [ 47 ] IAV transmissions within the backyards were also suggested. On the other hand, several studies (n = 14; 41.18%), including those that conducted sero-surveillance only [ 29 – 31 , 37 – 41 ], could not determine the epidemiology of IAV transmission in the backyards (Fig. 10 c).…”

“…10 e). A few serological investigations (n = 7; 18.92%) that detected IAV antibodies in backyard swine sera but did not report the subtype was because they only used ELISA assay [ 28 – 30 , 37 , 39 , 47 , 49 ] (Fig. 10 f).…”