A mixed methods study of ruminant brucellosis in central-eastern Tunisia

Abstract

In this study, we conducted an investigation to determine the true prevalence of bovine and ovine brucellosis in central-eastern Tunisia. A total of 1134 veterinary samples taken from 130 ruminant herds were screened for brucellosis using IS711-based real-time PCR assay. Sera collected from the ruminants were tested using the Rose Bengal test and indirect enzyme-linked immunosorbent assay. Based on serological and molecular results, the true adjusted animal population level prevalence was 23.5 % in cattle, against 13.5 % in sheep. In addition, the true adjusted herd level prevalence of brucellosis was 55.6 % in cattle and 21.8 % in sheep. A statistically significant association was found between vaginal and milk shedding for ruminants. In addition, our results showed that Brucella abortus could be responsible for bovine and ovine brucellosis. Multivariable logistic regression analysis at the animal population level indicated that age and origin variables were important risk factors for cattle. However, age and abortion variables were found to be associated with ovine brucellosis. At the herd level, risk factors for Brucella positivity were as follows: abortion and herd composition for cattle against herd composition, mortality rates, and hygiene for sheep. Animal hygiene, food quality, and sanitary practices on the farm should be applied as strategies to control brucellosis in herds.

Molecular prevalence of Chlamydia and Chlamydia-like bacteria in Tunisian domestic ruminant farms and their influencing risk factors

“…Our results have shown that the probability of having a positive animal was higher in urban (17%) than in peri‐urban (5.26%) and rural (11.1%) areas. This could be explained by the fact that most dairy farmers practicing the intensive farming are situated in urban areas where there is a high demand for milk (Barkallah et al., ; Jaouad, ). In this type of areas, reproductive infections associated with Chlamydiae , particularly abortions, appear mainly as enzootic diseases, resulting in severe economic losses (Igayara‐Souza et al., ).…”

“…During this study, many geographical regions of Sfax have been visited as described by Barkallah et al. (). In each region, households owning cattle and/or sheep were identified through discussion with responsible veterinarians during the annual vaccination campaigns.…”

“…The number of herds to be studied was calculated using the following formula n = [ t 2 Pexp (1‐Pesp)]/ d 2 as previously described by Barkallah et al. (). In total, 20 Holsteins bovine herds and 110 ovine herds were visited.…”

“…This study was conducted in Sfax town (average altitude of 13 m), which is located in the East Centre of Tunisia, at 270 km from the capital Tunis. During this study, many geographical regions of Sfax have been visited as described by Barkallah et al (2017). In each region, households owning cattle and/or sheep were identified through discussion with responsible veterinarians during the annual vaccination campaigns.…”

“…In each region, households owning cattle and/or sheep were identified through discussion with responsible veterinarians during the annual vaccination campaigns. The number of herds to be studied was calculated using the following formula n = [t 2 Pexp (1-Pesp)]/d 2 as previously described by Barkallah et al (2017). In total, 20 Holsteins bovine herds and 110 ovine herds were visited.…”