Serological Evidence of Infectious Laryngotracheitis Infection and Associated Risk Factors in Chickens in Northwestern Ethiopia.

Infectious laryngotracheitis (ILT) is a disease of high economic consequence to the poultry sector. Gallid herpesvirus 1 (GaHV-1), a.k.a infectious laryngotracheitis virus (ILTV), under the genus Iltovirus, and the family Herpesviridae, is the agent responsible for the disease. Despite the clinical signs on the field suggestive of ILT, it has long been considered nonexistent and a disease of no concern in Ethiopia. A cross-sectional study was conducted from November 2020 to June 2021 in three selected zones of the Amhara region (Central Gondar, South Gondar, and West Gojjam zones), Ethiopia, with the objective of estimating the seroprevalence of ILTV in chickens and identifying and quantifying associated risk factors. A total of 768 serum samples were collected using multistage cluster sampling and assayed for anti-ILTV antibodies using indirect ELISA. A questionnaire survey was used to identify the potential risk factors. Of the 768 samples, 454 (59.1%, 95% CI: 0.56-0.63) tested positive for anti-ILTV antibodies. Mixed-effect logistic regression analysis of potential risk factors showed that local breeds of chicken were less likely to be seropositive than exotic breeds (OR: 0.38, 95% CI: 0.24-0.61). In addition, factors such as using local feed source (OR: 6.53, 95% CI: 1.77-24.04), rearing chickens extensively (OR: 1.97, 95% CI: 0.78-5.02), mixing of different batches of chicken (OR: 14.51, 95% CI: 3.35-62.77), careless disposal of litter (OR: 1.62, 95% CI: 0.49-4.37), lack of house disinfection (OR: 11.05, 95% CI: 4.09-47.95), lack of farm protective footwear and clothing (OR: 20.85, 95% CI: 5.40-80.45), and careless disposal of dead chicken bodies had all been associated with increased seropositivity to ILTV. Therefore, implementation of biosecurity measures is highly recommended to control and prevent the spread of ILTV. Furthermore, molecular confirmation and characterization of the virus from ILT suggestive cases should be considered to justify the use of ILT vaccines.

Assessment of risk factors and isolation of Staphylococcus aureus and Escherichia coli from bovine subclinical mastitic milk in and around Gondar, Northwest Ethiopia.

A cross-sectional study with simple random sampling approach was conducted from November 2017 to May 2018 with the objectives of estimating the prevalence of subclinical mastitis with its associated risk factors and to identify and isolate Staphylococcus aureus and Escherichia coli from mastitic milk in and around Gondar town, Ethiopia. The study was conducted on 334 lactating cows selected from 70 smallholder dairy farms. California mastitis test (CMT) and bacteriological culture methods were used as diagnostic tools. From 334 cows examined, 114 (34.1%) and from 1054 quarters examined, 238 (17.8%) were positive for subclinical mastitis using CMT test. Adult and old cows were 3.681 (95% CI = 1.541, 8.788) and 15.044 (95% CI = 3.051, 74.174) times more likely to have a chance of contracting mastitis than young cows respectively. Cow's having 4-7 calving were 88.9% (OR = 0.111, 95% CI = 0.29, 0.423) less likely to have a chance of contracting mastitis than cows having ≤ 3 calving by keeping another factors constant. Mid-lactating cows were 63.4% (OR = 0.366, 95% CI = 0.150, 0.890) less likely to have a chance of contracting mastitis than cows in the early lactation stage. Crossbreed cows were also 79.1% (OR = 0.209, 95% CI = 0.046-0.948) less likely to have a chance of contracting mastitis than local breed cows. The odds of subclinical mastitis were 21.81 (95% CI = 4.618, 103.002) times higher in cows having tick infestation compared to cows without tick infestation and animals kept in good housing were 23% (OR = 0.73, 95% CI = 0.027, 0.197) less likely to have mastitis than cows kept in poor housing. The likelihood of mastitis occurrence was 3.372 (95% CI = 0.865, 13.141) times higher in cows managed in intensive farming system than semi-intensive farming system. Out of fifty CMT positive milk samples, proportion of Staphylococcus aureus and Escherichia coli was 17 (34%) and 8 (16%) respectively. As a conclusion, subclinical mastitis is the main important health constraints of dairy cows in the study area. Therefore, management, housing, and environmental sanitation should be improved.