136 Bassirou Bonfoh et al. Oblast species Naryn Oblast Humans Cattle Sheep Goats Chuy Oblast Humans Cattle Sheep Goats Osh Oblast Humans Cattle Sheep Goats n 564 536 562 561 606 598 610 434 604 564 857 214 18.3 2.2 8.9 2.5 8.9 5.7 3.0 2.7 2.2 1.6 1.3 2.8 14.0–23.7 0.8–6.0 5.8–13.5 0.9–7.0 6.9–11.5 4.1–7.9 0.0–9.7 1.3–5.7 0.1–27.6 0.5–4.5 0.4–3.9 1.3–6.1 Sex Female Male Age category 0–18 19–45 >45 Oblast Naryn Chuy Osh n 1,011 750 128 1,049 584 560 600 601 Table 2. Apparent seroprevalence estimates of brucellosis in Kyrgyzstan for humans, cattle, sheep, and goats per oblast, 2006 Table 3. Risk factors of human seropositivity determined with the Huddleson test as outcome variable Seroprevalencea 95% CI Variable Huddleson test aSeroprevalences (and 95% CI) calculated with a logistic regression model specifying Rayon as a random effect. Osh Oblast. Using Rayon as a random effect, the overall representative apparent seroprevalences of brucellosis for Kyrgyzstan were 8.8% in humans (95% CI 4.5–16.5), 2.8% (95% CI 1.6–4.9%) in cattle, 3.3% (95% CI 1.5– 6.9%) in sheep, and 2.5% (95% CI 1.4–4.5%) in goats. The average duration of brucellosis seropositivity (1/b) was estimated at 10.9 years. Keeping this constant, human incidence of apparent sero-conversion is estimated at 0.88% (95% CI 0.43–1.77%) per year for the Huddleson test. This means that on average 880 (95% CI 400–1,770) persons per 100,000 are exposed to brucellosis per year. Extrapolated to the total Kyrgyz population of 5.2 mil- lions on average 45,882 persons per year get exposed to brucellosis. Analysis of Human Sera for Risk Factors of Brucellosis Seropositivity Additional data on age, sex, and village was available for 1,761 people. The proportion of sampled female partici- pants varied between 0.42 and 0.78 in the 9 Rayons and was 0.57 over the whole sample. The median age was 39 years (5–95% percentiles 17–66). More male participants were seropositive compared to females (in all three age classes) (OR = 1.96; p(LRT) < 0.001) (Table 3). Pos% OR 8.4 14.9 14.1 11.7 9.6 18.4 8.3 7.3 Univariable logistic regression model 1 1.96 (1.4–2.7) 1 1.2 (0.6–2.3) 1.03 (0.5–2) 1 0.4 (0.2–0.7) 0.2 (0.1–0.5) p(LRT) <0.001 0.60 <0.001 The uni- and multivariable models used a random effect on village level. P values of the log LRT are presented. Table 4. Regression coefﬁcients for human seropositivity and livestock seropositivity Intercept (95% CI) Slope (95% CI) All livestock species 0.09 (0.05–0.12) Small ruminants 0.08 (0.05–0.11) Cattle 0.15 (0.11–0.18) Sheep 0.07 (0.05–0.10) Goats 0.09 (0.07–0.12) 0.81 (-0.1 to 1.7) 0.97 (0.3 to 1.7) -0.88 (-1.8 to 0.2) 0.83 (0.3 to 1.4) 0.99 (-0.06 to 2.1) Correlation Between Human and Livestock Seropositivity On the Rayon level, both pooled small ruminant and sheep seroprevalences were correlated positively with human se- roprevalences: an increase of 1% of small ruminant and sheep seroprevalences, increased human seroprevalence by 0.97 and 0.83%, respectively (Table 4). DISCUSSION This study was designed as a representative cross-sectional assessment of brucellosis prevalence in humans and live- stock in Kyrgyzstan in 2006. Because of the highly endemic epidemiological situation, the true incidence of clinical brucellosis cannot be stated. The estimated incidence of