Transmission dynamics of foot and mouth disease in selected outbreak areas of northwest Ethiopia.

Foot and mouth disease (FMD) is a highly contagious and economically important disease of cloven-hoofed animals, which is endemic in Ethiopia. An outbreak follow-up study was undertaken to quantify the transmission parameters of FMD in the crop-livestock mixed (CLM) system and commercial dairy farms in selected areas of northwest Ethiopia. The transmission parameters were quantified using a generalised linear model (GLM) based on a susceptible-infectious-recovered (SIR) epidemic model. The per day average transmission rate between animals was 0.26 (95% CI 0.22-0.32) and 0.33 (95% CI 0.21-0.57) in the CLM system and in the commercial dairy farms, respectively. The average basic reproduction ratio of FMD was 1.68 (95% CI 1.42-2.07) in the CLM system and 1.98 (95% CI 1.26-3.42) in the commercial dairy farms. The medium per day transmission rate and moderate basic reproduction ratio observed in this study indicated that a vaccination coverage needed to stop transmission of the disease in these populations might not be very high.

Temporal and spatial distribution of lumpy skin disease outbreaks in Ethiopia in the period 2000 to 2015.

BACKGROUND: Lumpy skin disease (LSD) is an infectious viral disease of cattle caused by a virus of the genus Capripoxvirus. LSD was reported for the first time in Ethiopia in 1981 and subsequently became endemic. This time series study was undertaken with the aims of identifying the spatial and temporal distribution of LSD outbreaks and to forecast the future pattern of LSD outbreaks in Ethiopia. RESULTS: A total of 3811 LSD outbreaks were reported in Ethiopia between 2000 and 2015. In this period, LSD was reported at least once in 82% of the districts (n = 683), 88% of the administrative zones (n = 77), and all of the regional states or city administrations (n = 9 and n = 2) in the country. The average incidence of LSD outbreaks at district level was 5.58 per 16 years (0.35 year-1). The incidence differed between areas, being the lowest in hot dry lowlands and highest in warm moist highland. The occurrence of LSD outbreaks was found to be seasonal. LSD outbreaks generally have a peak in October and a low in May. The trend of LSD outbreaks indicates a slight, but statistically significant increase over the study period. The monthly precipitation pattern is the reverse of LSD outbreak pattern and they are negatively but non-significantly correlated at lag 0 (r = -0.05, p = 0.49, Spearman rank correlation) but the correlation becomes positive and significant when the series are lagged by 1 to 6 months, being the highest at lag 3 (r = 0.55, p < 0.001). The forecast for the period 2016-2018 revealed that the highest number of LSD outbreaks will occur in October for all the 3 years and the lowest in April for the year 2016 and in May for 2017 and 2018. CONCLUSION: LSD occurred in all major parts of the country. Outbreaks were high at the end of the long rainy season. Understanding temporal and spatial patterns of LSD and forecasting future occurrences are useful for indicating periods when particular attention should be paid to prevent and control the disease.

Transmission dynamics of lumpy skin disease in Ethiopia.

Lumpy skin disease (LSD) is a severe disease of cattle caused by a Capripoxvirus and often caused epidemics in Ethiopia and many other countries. This study was undertaken to quantify the transmission between animals and to estimate the infection reproduction ratio in a predominantly mixed crop-livestock system and in intensive commercial herd types. The transmission parameters were based on a susceptible-infectious-recovered (SIR) epidemic model with environmental transmission and estimated using generalized linear models. The transmission parameters were estimated using a survival rate of infectious virus in the environment equal to 0·325 per day, a value based on the best-fitting statistical model. The transmission rate parameter between animals was 0·072 (95% CI 0·068-0·076) per day in the crop-livestock production system, whereas this transmission rate in intensive production system was 0·076 (95% CI 0·068-0·085) per day. The reproduction ratio (R) of LSD between animals in the crop-livestock production system was 1·07, whereas it was 1·09 between animals in the intensive production system. The calculated R provides a baseline against which various control options can be assessed for efficacy.

The status of bovine brucellosis in Ethiopia with special emphasis on exotic and cross bred cattle in dairy and breeding farms.

A cross-sectional study was conducted to investigate the seroprevalence of brucellosis and identify risk factors in exotic and cross bred cattle in Ethiopia. A total of 2334 cattle from 273 farms were tested serially for Brucella antibodies using the Rose Bengal Plate Test (RBPT) and the Compliment Fixation Test (CFT). The overall animal level seroprevalence was 1.9% (95% CI: 1.2, 2.6), with urban and peri-urban dairy 2.4% (95% CI: 1.4, 3.4), commercial 1.5% (95% CI: 0.5, 2.5) and breeding farms 1.5% (95% CI: 0.2, 3.2). The overall farm level prevalence was 10.6% (95% CI: 6.9, 14.3), with 8.6% (95% CI: 4.8, 12.4) in urban and peri-urban dairy followed by 16.9% (95% CI: 7.3, 26.6) in commercial and 20.0% (95% CI: 0.0, 59.4) in breeding farms. At individual animal level, purchased cows and adult age groups were observed to associate with Brucella seropositivity while presence of small ruminants on the farm was the only factor associated with increased risk of herd level Brucella infection. The lack of association between reproductive disorders and Brucella seroprevalence suggest that other causes largely outweigh as causes of the aforesaid disorder in studied production systems and demands an investigation. Finally, the need for isolation and characterization of circulating Brucella spp. and institution of regulatory measures to reinforce farm biosecurity was suggested.

Occurrence and antimicrobial resistance of Salmonella serovars in apparently healthy slaughtered sheep and goats of central Ethiopia.

The present study was undertaken to determine the occurrence, distribution and antimicrobial resistance pattern of Salmonella serovars in apparently healthy slaughtered sheep and goats in central Ethiopia. A total 1224 samples consisting of faeces, mesenteric lymph nodes, liver, spleen, and abdominal and diaphragmatic muscle samples were collected from 104 sheep and 100 goats. Salmonella was isolated from 12 of 104 (11.5%) sheep and 3 of 100 (3%) goats. Of the total 624 and 600 samples examined from sheep and goats, 18 (2.9%) and 4 (0.7%), respectively, were Salmonella positive. The 22 Salmonella isolates belonged to 9 different serovars. The common serovars isolated were S. typhimurium, followed by S. heidelberg, S. reading, S. give, and S. poona. Seven of the 22 isolates (31.8%) were multidrug-resistant to various antimicrobials.