Q fever (caused by Coxiella burnetii) is thought to have an almost worldwide distribution, but fe... more Q fever (caused by Coxiella burnetii) is thought to have an almost worldwide distribution, but few countries have conducted national serosurveys. We measured Q fever seroprevalence using residual sera from diagnostic laboratories across Australia. Individuals aged 1-79 years in 2012-2013 were sampled to be proportional to the population distribution by region, distance from metropolitan areas and gender. A 1/50 serum dilution was tested for the Phase II IgG antibody against C. burnetii by indirect immunofluorescence. We calculated crude seroprevalence estimates by age group and gender, as well as age standardised national and metropolitan/non-metropolitan seroprevalence estimates. Of 2785 sera, 99 tested positive. Age standardised seroprevalence was 5.6% (95% confidence interval (CI 4.5%-6.8%), and similar in metropolitan (5.5%; 95% CI 4.1%-6.9%) and non-metropolitan regions (6.0%; 95%CI 4.0%-8.0%). More males were seropositive (6.9%; 95% CI 5.2%-8.6%) than females (4.2%; 95% CI 2.9%-5.5%) with peak seroprevalence at 50-59 years (9.2%; 95% CI 5.2%-13.3%). Q fever seroprevalence for Australia was higher than expected (especially in metropolitan regions) and higher than estimates from the Netherlands (2.4%; pre-outbreak) and US (3.1%), but lower than for Northern Ireland (12.8%). Robust country-specific seroprevalence estimates, with detailed exposure data, are required to better understand who is at risk and the need for preventive measures.
Coxiella burnetii, the zoonotic agent of Q fever, has a worldwide distribution including Iran. Ho... more Coxiella burnetii, the zoonotic agent of Q fever, has a worldwide distribution including Iran. However, no information regarding the circulating genotype of this infection has been reported in Iran. This study aimed to evaluate the genetic diversity of C. burnetii in Iran using the multi-spacer sequence typing (MST) method. First, 14 positive C. burnetii samples (collected from four sheep, three goats, and seven cattle) were confirmed using quantitative polymerase chain reaction (qPCR) targeting the IS1111 gene. Then, ten spacers (Cox 2, 5, 18, 20, 22, 37, 51, 56, 57, and 61) were amplified using PCR for future MST analysis. The in-silico MST genotyping analysis of domestic ruminant samples revealed two new alleles (Cox5.11 and Cox56.15) in Cox5 and Cox56 loci that led to the emergence of four novel MST genotypes (MST62, 63, 64, and 65) and one MST genotype that has been previously described (MST61). This study showed the circulation of five MST C. burnetii genotypes among Iranian d...
Q fever (caused by Coxiella burnetii) is thought to have an almost worldwide distribution, but fe... more Q fever (caused by Coxiella burnetii) is thought to have an almost worldwide distribution, but few countries have conducted national serosurveys. We measured Q fever seroprevalence using residual sera from diagnostic laboratories across Australia. Individuals aged 1-79 years in 2012-2013 were sampled to be proportional to the population distribution by region, distance from metropolitan areas and gender. A 1/50 serum dilution was tested for the Phase II IgG antibody against C. burnetii by indirect immunofluorescence. We calculated crude seroprevalence estimates by age group and gender, as well as age standardised national and metropolitan/non-metropolitan seroprevalence estimates. Of 2785 sera, 99 tested positive. Age standardised seroprevalence was 5.6% (95% confidence interval (CI 4.5%-6.8%), and similar in metropolitan (5.5%; 95% CI 4.1%-6.9%) and non-metropolitan regions (6.0%; 95%CI 4.0%-8.0%). More males were seropositive (6.9%; 95% CI 5.2%-8.6%) than females (4.2%; 95% CI 2.9%-5.5%) with peak seroprevalence at 50-59 years (9.2%; 95% CI 5.2%-13.3%). Q fever seroprevalence for Australia was higher than expected (especially in metropolitan regions) and higher than estimates from the Netherlands (2.4%; pre-outbreak) and US (3.1%), but lower than for Northern Ireland (12.8%). Robust country-specific seroprevalence estimates, with detailed exposure data, are required to better understand who is at risk and the need for preventive measures.
Coxiella burnetii, the zoonotic agent of Q fever, has a worldwide distribution including Iran. Ho... more Coxiella burnetii, the zoonotic agent of Q fever, has a worldwide distribution including Iran. However, no information regarding the circulating genotype of this infection has been reported in Iran. This study aimed to evaluate the genetic diversity of C. burnetii in Iran using the multi-spacer sequence typing (MST) method. First, 14 positive C. burnetii samples (collected from four sheep, three goats, and seven cattle) were confirmed using quantitative polymerase chain reaction (qPCR) targeting the IS1111 gene. Then, ten spacers (Cox 2, 5, 18, 20, 22, 37, 51, 56, 57, and 61) were amplified using PCR for future MST analysis. The in-silico MST genotyping analysis of domestic ruminant samples revealed two new alleles (Cox5.11 and Cox56.15) in Cox5 and Cox56 loci that led to the emergence of four novel MST genotypes (MST62, 63, 64, and 65) and one MST genotype that has been previously described (MST61). This study showed the circulation of five MST C. burnetii genotypes among Iranian d...
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Papers by John Stenos