Risk of Human Infections With Highly Pathogenic H5N2 and Low Pathogenic H7N1 Avian Influenza Strains During Outbreaks in Ostriches in South Africa.

Background: Risk factors for human infection with highly pathogenic (HP) and low-pathogenic (LP) avian influenza (AI) H5N2 and H7N1 were investigated during outbreaks in ostriches in the Western Cape province, South Africa. Methods: Serum surveys were conducted for veterinarians, farmworkers, and laboratory and abattoir workers involved in 2 AI outbreaks in the Western Cape province: (1) controlling and culling of 42000 ostriches during (HPAI)H5N2 outbreaks in ostriches (2011) (n = 207); (2) movement control during (LPAI)H7N1 outbreaks in 2012 (n = 66). A third serosurvey was conducted on state veterinarians from across the country in 2012 tasked with disease control in general (n = 37). Antibodies to H5 and H7 were measured by means of hemagglutination inhibition and microneutralization assays, with microneutralization assay titers >40 considered positive. Results: Two of 207 (1%) participants were seropositive for H5 and 4 of 207 (2%) for H7 in 2011, compared with 1 of 66 (1.5%) and 8 of 66 (13%) in 2012. Although individuals in all professions tested seropositive, abattoir workers (10 of 97; 10.3%) were significantly more at risk of influenza A(H7N1) infection (P = .001) than those in other professions (2 of 171;1.2%). Among state veterinarians, 4 of 37(11%) were seropositive for H7 and 1 of 37 (2.7%) for H5. Investigations of (LP)H7N1-associated fatalities in wild birds and quarantined exotic birds in Gauteng, AI outbreaks in poultry in KwaZulu-Natal, and ostriches in Western Cape province provide possible exposure events. Conclusion: (LPAI)H7N1 strains pose a greater infection-risk than (HPAI)H5N2 strains to persons involved in control of outbreaks in infected birds, with ostrich abattoir workers at highest risk.

Bacterial expression of Crimean-Congo hemorrhagic fever virus nucleoprotein and its evaluation as a diagnostic reagent in an indirect ELISA.

Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne viral zoonosis distributed widely in Africa, Asia, Russia and the Balkans. The emergence and re-emergence of CCHFV emphasize the importance of increasing both human and veterinary surveillance and developing diagnostic capacity. Recombinant CCHFV nucleocapsid protein (NP) has been expressed using insect cells and mammalian cells and used as a diagnostic tool but bacterial expression has not been described previously. The S gene of CCHFV was codon optimized and the NP expressed in Escherichia coli from the synthetic gene. The protein was reacted against serum samples collected from confirmed CCHFV patients at varying intervals after the onset of illness from acute to convalescent stages using both an ELISA and a Western blot. To confirm that the protein was able to induce a humoral antibody response that could be detected using CCHFV antigen derived from live virus, mice were immunized and serum samples were tested using IF slides prepared from CCHFV infected Vero cells. The recombinant antigen was able to detect IgG antibody in acute and convalescent sera. In addition, a detectable IgG antibody response was induced in mice immunized using NP. The results suggest that proteins expressed in a bacterial system lacking post-translational modifications can be used in ELISA to detect IgG antibody against CCHFV in human sera which may be used for routine diagnosis and seroepidemiology.