Foot and mouth disease in selected districts of western Ethiopia: seroprevalence and associated risk factors.

A study was conducted in western Ethiopia--in two districts of Oromia state and four districts of Beneshangul Gumuz state--to determine the seroprevalence of foot and mouth disease and the associated risk factors, using multistage random sampling. A 3ABC blocking enzyme-linked immunosorbent assay was used to measure antibody against the non-structural protein of foot and mouth disease virusto differentiate between vaccinated and infected animals.Atotal of 1,144 sera from 181 herds were collected and examined. The overall seroprevalence at animal level and herd level was 9% (95% Cl 7.2-10.6) and 38.1% (95% CI 29.1-47.1), respectively. Statistically significant differences (p < 0.05) were recorded among different species, with 13%, 5% and 3% seropositivity in cattle, sheep and goats, respectively. Statistically significant differences (p < 0.05) in herd seroprevalence were observed among districts, with 52%, 50%, 50%, 44%, 21% and 11% in Gidami, Begi, Tongo, Bambasi, Mange and Asosa districts, respectively. In univariable and multivariable logistic regression, the variables that had a positive relationship with seroprevalence at herd level (p < 0.05) were herd size, contact of livestock with ungulate wildlife, and contact of animals with animals/herds of a different peasant association. Univariable and multivariable logistic regression analysis indicated that, at the animal level, age and species had a statistically significant association (p < 0.05) with seropositivity. In conclusion, herd size, contact of livestock with ungulate wildlife, contact between herds from different peasant associations, and the age and species of the animals were the main risk factors for virus circulation in the study area.

Risk factors for foot and mouth disease seroprevalence in indigenous cattle in Southern Ethiopia: the effect of production system.

A serological survey to investigate risk factors for Foot and Mouth Disease (FMD) occurrence was conducted between October 2007 and March 2008 in Southern Ethiopia. Antibodies against non-structural protein of FMD virus (using 3abc ELISA) were measured as indicator of exposure to the virus. The seroprevalence of FMD was 9.5% (95%CI = 7.7 - 11.3, n = 1020) and 48.1% (95% CI = 36.8 - 59.4%, n = 79), respectively at animal and herd levels. Within herd seropositivity was ranged from 6.7 to 46.7% with 18.6% (95%CI = 14.6 - 22.5%) risk of being seropositive for an animal in positive herds. The most important herd level risk factors identified were pastoral system (OR = 16.3, 95% CI = 2.0 -133.7) compared to sedentary, low altitude (OR = 7.5, 95% CI 1.4 -40.7) compared to high altitude, keeping cattle with small ruminants (OR = 5.1, 95% CI 1.0 -25.2) when compared to one species or alone. Seroprevalence was significantly higher (P <0.05) in South Omo than Sidama and Gamo Gofa areas. The odds of seropositivity were 2.8 and 2.3 times higher in the adult (>4 years) and maturing animals (3-4 years) compared to young age category (<3 years). Both multivariable logistic and negative binomial regressions depicted that production system was the major risk factor for FMD seropositivity. Consequently, higher prevalence of FMD in pastoral system where animals are an integral part of life has substantial livelihood and economic implications, which signifies the need for devising control measures.

Foot and mouth disease in the Borana pastoral system, southern Ethiopia and implications for livelihoods and international trade.

Participatory epidemiology (PE) was used on the Borana plateau of southern Ethiopia to understand pastoralist's perceptions of the clinical and epidemiological features of foot and mouth disease (FMD) in cattle. Matrix scoring showed good agreement between informant groups on the clinical signs of acute and chronic FMD, and findings were cross-checked by clinical examination of cattle and assessment of previous clinical FMD at herd level by detection of antibody to non structural proteins of FMD virus. The positive predictive value of pastoralist's diagnosis of FMD at herd level was 93.1%. The annual age-specific incidence and mortality of acute FMD in 50 herds was estimated using proportional piling. The estimated mean incidence of acute FMD varied from in 18.5% in cattle less than two years of age to 14.0% in cattle three to four years of age. The estimated mean mortality due to acute FMD varied from 2.8% in cattle less than two years of age to 0.3% in cattle three of age or older. Pearson correlation coefficients for acute FMD by age group were -0.12 (p>0.05) for incidence and -0.59 (p<0.001) for mortality. Estimates of the annual incidence of chronic FMD varied from 0.2% in cattle less than two years of age to 1.8% in cattle three to four years of age. The Pearson correlation coefficient for the incidence of chronic FMD by age group was 0.47 (p<0.001). Outbreaks of FMD peaked in Borana cattle during the two dry seasons and were attributed to increased cattle movement to dry season grazing areas. The mean seroprevalence of FMD was estimated at 21% (n=920) and 55.2% of herds (n=116) tested seropositive. Serotyping of 120 seropositive samples indicated serotypes O (99.2%), A (95.8%), SAT 2 (80%) and C (67.5%). The endemic nature of FMD in Borana pastoral herds is discussed in terms of the direct household-level impact of the disease, and the increasing export of cattle and chilled beef from Ethiopia.