Seroprevalence of zoonotic abortive diseases and their associated risk factors in Tunisian sheep.

BACKGROUND: Abortion is a serious problem for sheep flocks and it is responsible for considerable economic losses. The epidemiological situation of abortion causing agents in sheep is poorly documented in Tunisia. This study aims to investigate the status of three abortion causing agents (Brucella spp, Toxoplasma gondii, and Coxiella burnetii) among organized flocks in Tunisia. RESULTS: A total of 793 sample blood collected from twenty-six flocks in seven governorates in Tunisia, were tested by indirect enzyme-linked immunosorbent assay (i-ELISA) for antibodies against three abortion causing agents (Brucella spp, Toxoplasma gondii, and Coxiella burnetii). Risk factors for individual-level seroprevalence were analyzed using a logistic regression model. Results revealed that 19.7%, 17.2%, and 16.1% of the tested sera were positive for toxoplasmosis, Q fever, and brucellosis, respectively. Mixed infection was found in all the flocks with 3 to 5 responsible abortive agents simultaneously. Logistic regression showed that the management practices (control of new introduction, common grazing and watering point, workers exchange, presence of lambing box on the farm) and the history of infertility and the presence of abortion in neighboring flocks were likely to increase the probability of being infected by the three abortive agents. CONCLUSIONS: Evidence of the positive relationship between seroprevalence of abortion causing agents and several risk factors, suggests further investigations to better understand the etiology of infectious abortions in flocks to develop an applicable preventive and control program.

Estimation of the economic impact of a bluetongue serotype 4 outbreak in Tunisia.

Introduction: Since 1999, Tunisia has experienced multiple occurrences of Bluetongue (BT) outbreaks, leading to numerous reported cases of infection and mortality in flocks. The re-emergence of the disease in 2020 caused substantial economic losses in cattle, attributed to the incursion of serotype BTV-4. Methods: To evaluate the economic impact of the recent BT episode, we conducted a retrospective study on outbreaks that occurred in Tunisia between August and November 2020, focusing on the impact at the owner's level and its effects on both small ruminants and cattle. A total of 234 ruminant farms (sheep, cattle, and mixed) were randomly selected across Tunisian governorates and included in the study to estimate both the direct and indirect costs of these outbreaks. Results: Total costs were calculated as the sum of losses and expenditures resulting from the BT outbreaks. At the animal level, total losses were estimated to range between 116.280 and 207.086 TND for one infected ewe (€33.721 and 60.055). For one lactating cow, costs varied between 2,590.724 and 3,171.107 TND (€751.310 and 919.621). In cattle, exposure to BTV led to a daily unit milk yield decrease of 12.50 to 14.66 L over an average period of 5 months. Diseased sheep experienced weight loss ranging between 4 and 10 kg during the BT outbreaks. The total mean cost of the 2020 BT outbreak in Tunisian investigated farms was estimated at 1,935 million TND (million €561.15) (range: 1,489 and 2,474 million TND; 431.81 and million €717.46). The most influential costs of the total BT outbreaks were the decrease in milk yield, mortality, and veterinary treatment. Discussion: This study gives valuable insights on the economic impact of the incursion of a new serotype of BT in a naive population in Tunisia. Considering the substantial costs incurred, it is imperative that this disease receives increased attention from stakeholders, including animal owners, veterinary services, practitioners, and decision-makers.

Risk based serological survey of Rift Valley fever in Tunisia (2017-2018).

Rift Valley fever (RVF) has been reported in the sub-Saharan region of Africa, Egypt and Arabian Peninsula - Yemen and Saudi Arabia, over the past 20 years and is a threat to both the animal and human populations in Tunisia. Tunisia is considered as a high-risk country for the introduction of RVF due to the informal movements of diseased animals already reported in the neighboring countries. The objective of this study was to assess the status of RVF in small ruminants and camels in Tunisia. A risk-based serological survey was conducted to evaluate the presence of RVF based on spatial qualitative risk analysis (SQRA). Samples were collected from small ruminants (sheep and goats) (n = 1,114), and camels (n = 173) samples, belonging to 18 breeders in 14 governorates between November 2017 and January 2018. Samples were tested using an RVF specific multispecies competitive ELISA. Out of the 1,287 samples tested for the presence of RVF IgG antibodies by ELISA, only one positive sample 0.07% (1/1 287) was detected but not confirmed with the virus neutralization test (VNT) used for confirmation. So far, no RVF outbreaks have been reported in Tunisia and our study confirmed the absence of RVF in livestock up to January 2018. Further investigations are needed to confirm the RVF-free status of Tunisia today.