Serological and molecular survey of brucellosis and chlamydiosis in dromedary camels from Tunisia.

The present sero-epidemiological survey was designed and conducted to scrutinize the current status of camel-related brucellosis and chlamydiosis in Tunisia. Whole blood and serum samples were collected from 470 dromedaries (Camelus dromedarius) from eight different Tunisian governorates. Serum samples were subjected to indirect enzyme-linked immunosorbent assay (iELISA). The detection of Brucella and Chlamydia DNA was performed using conventional PCR targeting the bcsp-31 and 16 S rRNA gene, respectively. Overall, 10/470(2.12%) and 27/470 (5.75%) camels were revealed seropositive to Brucella and Chlamydia, respectively. Multivariate logistic regression analysis showed different risk factors associated with these infections. Meaningful high rates of seropositivity of brucellosis (9.5%; p = 0.000; OR=64.193) and chlamydiosis (22.6%; p = 0.000; OR=42.860) were noted among camels showing previous abortions in particular for aged females. Besides, Chlamydia seropositivity is significantly important during winter (12.5%; p = 0.009; OR= 27.533), and in camels raised in small farms (11.4%, p = 0.000, OR=86.052). Molecular analysis revealed no positivity from all analyzed blood samples. These findings indicate the involvement of camels in the epidemiology of these abortive infectious diseases. This raises awareness and serious public health concern for infectious camel diseases in order to develop further diagnostic improvements and effective control strategies.

Prevalence of Escherichia coli O157:H7 isolated from fecal samples of diarrheic camels in Tunisia.

Shiga­toxin­producing E. coli (STEC) is a foodborne pathogen associated with outbreaks worldwide that can be identified in the feces and in the meat of food­producing animals. Our study aimed to evaluate the incidence of E. coli O157:H7 in the feces of diarrheic camels (Camelus dromedarius) in Tunisia. From January 2018 to April 2019, 120 unduplicated fecal samples were obtained from diarrheic camels located in southern Tunisia. Non­sorbitol­fermenting colonies were confirmed as E. coli O157 via latex agglutination test and were screened for the presence of rfbEO157, fliCH7, stx1, stx2, eaeA, and ehxA genes by PCR. All isolates were examined for their susceptibility to 21 antibiotics. Of the 70 E. coli isolates that were recovered from 120 diarrheic camels, 4 (5.7%) were identified as STEC O157:H7. All isolates harbored ehxA and eae genes. Shiga toxin genes stx2 and stx1 were present in 50% and 25% of isolates, respectively. All E. coli O157:H7 isolates were sensitive to amoxicillin/clavulanic acid, cefotaxime, cefepime, aztreonam, colistin, and sulfamethoxazole­trimethoprim. All isolates belonged to the phylogroup E. This is the first report of E. coli O157:H7 isolates from diarrheic camels in Tunisia with a prevalence of 4 isolates (3.3%) amongst 120 fecal samples. This study supports the necessity for a platform purposed for regular screening and surveillance programs in food­producing animals and meat products, to perform early and rapid identification of food­borne pathogens.

Serological survey and associated risk factors' analysis of Trypanosomiasis in camels from Southern Tunisia.

Surra (Trypanosoma evansi infection) is one of the main causes of dromedary (Camelus dromedarius) abortion, besides generating severe economic losses in herds. A sero-epidemiological survey was carried out between December 2018 and December 2019 in Southern Tunisia to estimate the seroprevalence of Trypanosoma evansi infection in camels and to determine its possible associated risk factors. Two-stage sampling was conducted to select breeders and camels targeted in our study. A total of 1205 blood samples were collected from 277 randomly selected farms belonging to six governorates of southern Tunisia. Sera were tested with the card agglutination test for Trypanosoma evansi (CATT/T. evansi) to detect the presence of anti-Trypanosoma. evansi antibodies. The overall individual and herd seroprevalence were 30.8% (95%CI 27.9-33.1%), 64.9% (95%CI 61.7-73), respectively. The seroprevalence of T. evansi infection both at the animal (26.2% (95%CI 21.4-30.9%) and herd level (84.4 (95%CI 76.3-92.5)) was higher in Kebili than in other governorates (P = 0.003). At the animal level, the infection rate with T. evansi was significantly associated to the age group among camels (P = 0.0008), production system (P = 0.006), bioclimatic stage (P = 0.02), and herd size (P = 0.04) in the univariable analysis. Multivariable logistic regression indicated that only age group and herd size were potential risk factors associated with Trypanosoma evansi infection. However, no significant variation of the seroprevalence of T. evansi with the sex of camels, farm type, and previous trypanocidal treatment were detected (P > 0.05). The findings of this study are crucial for this disease surveillance and control. Further investigations on the efficacy of the treatment against surra are needed to explain the persistence of the disease in the south of Tunisia.

Various Inc-type plasmids and lineages of Escherichia coli and Klebsiella pneumoniae spreading blaCTX-M-15,blaCTX-M-1 and mcr-1 genes in camels in Tunisia.

OBJECTIVES: Resistance to extended-spectrum cephalosporins, fluoroquinolones and colistin is under constant scrutiny in food-producing animals worldwide. However, little is known about camels, which provide milk and meat for human consumption, and are attractions for tourists to ride in arid regions. This study assessed the role of camels as potential reservoirs of these resistance determinants. METHODS: Faecal swabs were collected from 232 camels in Tunisia between April 2016 and July 2018. Enterobacteriaceae were detected on MacConkey agar and extended-spectrum ß-lactamase (ESBL)-producers on the same medium supplemented with cefotaxime. Antimicrobial resistance was assessed by disc diffusion, and ESBL-producing isolates were further characterised by phylogrouping (for Escherichia coli, E. coli) and multilocus sequence typing. Genetic support of the blaESBL and mcr-1 genes was identified by plasmid-typing and Southern blot. RESULTS: E. coli were identified in 163 of 232 (70.3%) and Klebsiella pneumoniae (K. pneumoniae) in 16 of 232 (6.9%) of the dominant flora. Three E. coli and one K. pneumoniae (1.3% and 0.4%, respectively) were found on cefotaxime-enriched media. One K. pneumoniae and one E. coli from a tourist farm harboured the blaCTX-M-15 gene on an IncY plasmid, while the two E. coli from the butchery sector displayed the blaCTX-M-15 gene on an IncI1 plasmid and colocalisation of the blaCTX-M-1 and mcr-1 genes on an IncHI2 plasmid. CONCLUSIONS: This study reported ESBL-producing Enterobacteriaceae in Tunisian camels from both tourist and meat-producing sectors. This was the first description of the mcr-1 gene in a meat-producing camel. Although not alarming, this context needs specific attention to avoid camels becoming a bigger reservoir for multidrug-resistant Enterobacteriaceae.

Coxiella burnetii in Tunisian dromedary camels (Camelus dromedarius): Seroprevalence, associated risk factors and seasonal dynamics.

Q fever, caused by Coxiella burnetii, is a zoonotic disease responsible of abortion in ruminants. Few studies have investigated the prevalence of this infection in camels (Camelus dromedarius). The present report aimed to highlight the epidemiological status and identify the risk factors associated with C. burnetii infection in one-humped dromedary that is the most productive livestock species in arid areas. A total of 534 sera of healthy camels were collected in eight governorates from southern and central Tunisia. Samples were tested by an indirect Enzyme linked Immunosorbent Assay (ELISA). Results were analyzed using the Chi-square test and logistic regression. Overall, 237 camels (44%, 95%CI: 0.40-0.49) were seropositive to C. burnetii. Statistical analysis pointed out four potential risk factors associated with infection. A meaningful high seropositivity was observed in female camels with a previous history of abortion (70%) (OR = 4.186, 95%CI: 2.05-8.51). Seroprevalence was higher in aged camels (>10 years-old) (48%) (OR = 2.91, 95%CI: 1.37-6.17). Besides, camels, intended for meat production from small herds showed a high level of infection (52%) (OR = 2.43, 95%CI: 1.3-4.5). Coxiellosis evolved in dromedary herds throughout the year, however infection was significantly important in autumn (60%) (OR = 4.13, 95%CI: 1.86-9.17) and winter (56%) (OR = 5.52, 95%CI: 2.50-12.16). Bioclimatic stage, gender, tick infestation and contact with other ruminants were not risk factors in camel's infection by C. burnetii. Our reports confirm that Tunisian one-humped dromedaries had been exposed to this bacterium and could contribute to its dissemination among farmers and other livestock animals. Furthers studies are required to evaluate the prevalence of Q fever among people professionally exposed like farmers, veterinarians and slaughterhouse workers.

Nonlinear integral sliding mode control design of photovoltaic pumping system: Real time implementation.

The aim of this paper is to provide high performance control of pumping system. The proposed method is designed by an indirect field oriented control based on Sliding Mode (SM) technique. The first contribution of this work is to design modified switching surfaces which presented by adding an integral action to the considered controlled variables. Then, in order to prevent the chattering phenomenon, modified nonlinear component is developed. The SM concept and a Lyapunov function are combined to compute the Sliding Mode Control (SMC) gains. Besides, the motor performance is validated by numeric simulations and real time implementation using a dSpace system with DS1104 controller board. Also, to show the effectiveness of the proposed approach, the obtained results are compared with other techniques such as conventional PI, Proportional Sliding Mode (PSM) and backstepping controls.

Geographic distribution of MERS coronavirus among dromedary camels, Africa.

We found serologic evidence for the circulation of Middle East respiratory syndrome coronavirus among dromedary camels in Nigeria, Tunisia, and Ethiopia. Circulation of the virus among dromedaries across broad areas of Africa may indicate that this disease is currently underdiagnosed in humans outside the Arabian Peninsula.