Evidence of exposure and human seroconversion during an outbreak of avian influenza A(H5N1) among poultry in Cameroon

Abstract

From May 2016 to March 2017, 22 poultry outbreaks of avian influenza A(H5N1) were reported in Cameroon, mainly in poultry farms and live bird markets. No human cases were reported. In this study, we sought to describe the 2016 A(H5N1) outbreak strain and to investigate the risk of infection in exposed individuals. We find that highly pathogenic influenza subtype A(H5N1), clade 2.3.2.1c from Cameroon is closely related phylogenetically and antigenically to strains isolated in central and western Africa at the time. No molecular markers of increased human transmissibility were noted; however, seroconversion was detected in two poultry workers (1.5% of total screened). Therefore, the continued outbreaks of avian influenza in poultry and the risk of zoonotic human infection highlight the crucial need for continued and vigilant influenza surveillance and research in Africa, especially in areas of high poultry trade, such as Cameroon.

Highly pathogenic avian influenza A(H5N1) in animals: A systematic review and meta-analysis

“…According to titles and abstracts, 648 studies were excluded from the screening. In turn, screening by full-text left 33 studies with all eligibility criteria Table 1 [ [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] , [24] , [25] , [26] , [27] , [28] , [29] , [30] , [31] , [32] , [33] , [34] , [35] , [36] , [37] , [38] , [39] , [40] , [41] , [42] , [43] , [44] , [45] , [46] , [47] , [48] ]. The flowchart of the selection process is shown in Fig.…”

Transmission experiments support clade-level differences in the transmission and pathogenicity of Cambodian influenza A/H5N1 viruses

“…Meanwhile, live bird market surveillance and poultry outbreak investigations have established that high levels of clade 2.3.2.1c viruses have circulated in poultry populations during this time [14], suggesting that this virus is less able than its predecessors to jump the species gap into humans. Global data appear to support this hypothesis, with there being few reports of clade 2.3.2.1c virus infections in humans, despite widespread poultry circulation in China, Indonesia, Vietnam, and West Africa [25][26][27][28][29]. The frequent detection of clade 2.3.2.1 viruses in wild birds and their rapid global dissemination [24,30] may indicate that these viruses are more "avian-like," affecting their ability to infect humans.…”

Molecular and serological prevalence of influenza A viruses in poultry and poultry farmers in the Ashanti region, Ghana

“…In contrast, infections, acute and past, with seasonal human IAV subtype H1N1 was detected. In Nigeria, Cameroon, and Egypt where H5 and H7 antibodies have been detected in poultry workers, the corresponding avian viruses were observed to have circulated for longer periods and affected more poultry holdings, increasing the net exposure risk of poultry workers with possibly infected poultry [15,16,34]. Nevertheless, farmers' compliance with certain basic biosafety practices were largely poor as noted previously in other parts of the country [18][19][20] and therefore the risk of exposure to zoonotic AIVs such as LPAIV H9N2 [29] and other non-viral avian pathogens remains high.…”

“…There has been a growing interest in AIV infections in Africa following the introduction of HPAIV H5N1 in gallinaceous poultry in 2006 [1], contributing to the identification of different AIV subtypes with known and unknown zoonotic propensities in birds on the continent [5,[10][11][12][13][14]. Simultaneously, evidence of AIV infections, exposures and death among humans in regular contact with poultry on the continent have also increased [9,15,16].…”