H9N2 avian influenza virus antibody titers in human population in fars province, Iran

Abstract

Among the avian influenza A virus subtypes, H5N1 and H9N2 viruses have the potential to cause an influenza pandemic because they are widely prevalent in avian species in Asia and have demonstrated the ability to infect humans. This study was carried out to determined the seroprevalence of H9N2 avian influenza virus in different human populations in Fars province, which is situated in the south of Iran. Antibodies against H9N2 avian influenza virus were measured using hemagglutination-inhibition (HI) test in sera from 300 individuals in five different population in Fars province, including poultry-farm workers, slaughter-house workers, veterinarians, patients with clinical signs of respiratory disease, and clinically normal individuals, who were not or rarely in contact with poultry. Mean antibody titers of 7.3, 6.8, 6.1, 4.5, and 2.9 and seroprevalences of 87%, 76.2%, 72.5%, 35.6%, and 23% were determined in those groups, respectively. Higher prevalences were detected in poultry-farm workers, slaughter-house workers, and veterinarians, possibly due to their close and frequent contact with poultry

Risk factors for H7 and H9 infection in commercial poultry farm workers in provinces within Pakistan

“…Comparable results have also been found in neighbouring countries of Pakistan such as Iran (Hadipour, 2010). The overall prevalence for H9 antibodies was higher than that of H7 in serum samples obtained from poultry workers in this study.…”

“…A highly variable infection rate with H9 virus, with a variable titre of HI cut-off (1:10-1:160) has been reported in people from various countries: around 87% of poultry farm workers in Iran (Hadipour, 2010); 2.3-4.5% in poultry workers in China Huang et al, 2013); 6.7% in people exposed to domestic and wild birds in the USA (Kayali et al, 2008). It is reasonable to assume therefore that poultry farm workers in Pakistan might also be infected.…”

Influenza research in the Eastern Mediterranean Region: the current state and the way forward

“…Sero‐epidemiologic studies from Iran found serologic evidence of previous infection with H9N2 among several subgroups of individuals. Antibody titers were highest among individuals exposed to poultry . In a recent study, Lebanese researchers found that 32·3% of individuals exposed to poultry sick with H9N2 viruses showed elevated antibody titers against viruses of the same type…”

Weighing serological evidence of human exposure to animal influenza viruses − a literature review

“…Some studies compared occupational groups, and many of them find differences in seroprevalence between different occupational groups, which are postulated to reflect differences in exposure [31,42,43,49,56,62,67,68,70-73,79,93,96,116,117]. A problem is that influenza infections were rarely measured in the animals to which the study population was exposed at the time of the study, therefore making it difficult to assess the true levels of exposures.…”

“…A problem is that influenza infections were rarely measured in the animals to which the study population was exposed at the time of the study, therefore making it difficult to assess the true levels of exposures. The lack of this information may in part explain the seemingly contrasting conclusions reached regarding the occupational groups that have the highest seroprevalence to animal influenza: some studies find the highest antibody titres in veterinarians [43,72] while others find the highest titres in farmers [56,70], abattoir workers [31] or poultry market workers [68]. Moreover, the term ‘occupational exposure’, as well as different occupational groups are loosely defined, which makes them very hard to compare.…”