Iranian Journal of Veterinary Research
Volume:20 Issue: 4, Autumn 2019

Listeria monocytogenes, as a foodborne pathogenic bacterium, is considered as major causative agent responsible for serious diseases in both humans and animals. Milk and dairy products are among the main sources of energy supply in the human, therefore contamination of these products with Listeria spp., especially L. monocytogenes, could lead to life threatening infections in a large population of people. Rapid and accurate detection of L. monocytogenes in milk and dairy products, vegetables, meat, poultry, and seafood products is needed to prevent its dissemination through the food chain. Upon contamination of food materials with this pathogen, increase in its antibiotic resistance rate can occur after exposure to preservatives, antibiotics, and stress conditions, which has now become another major public health concern emphasizing the need for special attention on its control along the food chain and management of the disease in the patients. This review provides an overview of researches with respect to the prevalence of Listeria spp., especially L. monocytogenes, in milk and dairy products, methods of their detection and typing, and current status of resistance rates to the antibiotics used for treatment of listeriosis.

Diarrheagenic Escherichia coli (DEC) is regarded as a great public health concern all around the world causing diarrhoea which can be transmitted through food chain.

This study aimed to determine the contamination level and exact distribution rate of DEC in food products consumed by human.

Seven hundred and twenty samples of food from animal origin and fishes were analysed by conventional and molecular method for the presence of E. coli and two multiplex polymerase chain reaction (mPCR) for detection of DEC.

Two hundred and eighty-three E. coli isolates were detected. The classification of DEC by two multiplex PCR assay yielded 84 DEC pathotypes. Enterotoxigenic E. coli (ETEC) was detected at high rates (75%) followed by shiga-toxigenic E. coli (STEC) and enterohemorrhagic E. coli (EHEC) (each of 9.5%), enteroaggregative E. coli (EAEC) (3.5%) and atypical enteropathogenic E. coli (aEPEC) (about 2.3%). The highest number of DEC (n=26; 21.6%) was observed from beef carcasses in abattoir while the lowest number (n=7; 5.8%) was noticed from burger samples (P<0.01). Enterotoxigenic E. coli was widespread in local raw ground meat and fish surface swabs (P<0.001), EAEC (P<0.01), and EHEC (P<0.001) were only in beef carcasses swabs, STEC was more prevalent in both imported and local raw burger (P<0.01), while the isolates of aEPEC were from imported chicken carcasses (P>0.05).

High DEC contamination rate that was observed is attributed to the poor hygienic practices during food processing. Therefore, a superior hygienic application is required.

Aflatoxins are fungal secondary metabolites negatively affecting ruminant performance; however, little information is available on their impact on rumen fermentation.

This study aimed at determining the effects of different concentrations of aflatoxin B1 (AFB1) from Aspergillus flavus on in vitro gas production and ruminal fermentation parameters using two experiments (Exp.).

In Exp. 1, two concentration ranges (0, 0.5, 1, and 1.5 µg/ml of rumen inoculum as low and 0, 5, and 10 µg/ml as high concentration ranges) were used to evaluate AFB1 effect on gas production kinetics using 96-h incubations. In Exp. 2, only the high concentration range was used to investigate AFB1 effects on ruminal fermentation parameters using 24-h incubations.

In the low concentration range, the half-time of asymptotic gas production (T1/2) increased and the fractional rate of gas production (µ) decreased linearly with AFB1 dosage (P<0.05). However, in the high concentration range, the asymptotic gas production (A) and T1/2 decreased; and the lag time (L) and “µ” increased linearly (P<0.001) by increasing the concentrations of AFB1. In Exp. 2, dry matter (DM) and organic matter (OM) disappearance, microbial biomass (MB) and total volatile fatty acids (TVFA) concentrations were depressed, but pH and ammonia-N concentration increased (P<0.01) by increasing the concentrations of AFB1. The pattern of rumen volatile fatty acids (VFAs) was also modified by AFB1, as the propionate proportion increased at the expense of acetate.

Aflatoxin B1 had an adverse effect on in vitro ruminal fermentation parameters in high concentration ranges (5 and 10 µg/ml).

The equine colic, which is caused by the presence of enteroliths that are most often found in the small or large colon, is typical for certain geographical regions (dry and hot climate). A diet rich in alfalfa is one of the highest risk factors. The earliest symptoms include weight loss and repeated episodes of colic pain.

To present the results of operative treatment of 15 horses with enteroliths in Saudi Arabia.

Fifteen purebred Arabian horses in Saudi Arabia, aged between 2 and 18 years, were treated. Decision about the surgery was based on clinical exam, ultrasound and rectal examination. The surgery was done on recumbent position in every case, under general inhalation anesthesia performed with izofluran.

Midline laparotomy was performed in all cases. Additional left flank laparotomy was performed in one horse, in which the stone was located in the proximal part of the small colon and parainguinal laparotomy was performed in 1 horse, in which the stone was located distally in the small colon. In each case, pelvic flexure enterotomy was performed in order to empty the large colon. Additionally, four horses underwent ventral colon enterotomy due to the presence of large stones. Small colon enterotomy was performed in 9 horses. In 12 cases treatment outcome was good and in 3 - poor. Chemical analysis of the stones showed similar

calcium, calcium oxalate, ammonium, phosphates, and magnesium (Mg) were obtained in all these cases but there were quantitative differences accounting for 15 to 30%, 10 to 20%, 10%, 20 to 40%, and 10 to 15%, respectively.

The results of surgery are generally good if stones are located in the large colon, but the prognosis is worse if they are located in the small colon, particularly in its proximal part. There is a huge importance of X-ray examination, which allows accurate diagnosis for locating the enteroliths and making a decision about surgery.

Air in broiler houses is contaminated with considerable amounts of microbial aerosols, which affects the health of humans and birds. Thorough cleaning and disinfecting should be carried out to reduce particulate concentrations and minimize airborne microorganisms.

To evaluate the effects of cleaning and disinfecting measures on bacterial communities in particulate matter less than 2.5 μm (PM2.5) and particulate matter between 2.5 and 10 μm (PM10) inside broiler houses.

A mixed disinfectant (containing aldehydes, alcohol, and quaternary ammonium salt) was sprayed to decontaminate broiler cage houses. 16S rDNA amplicon sequencing was performed in this study to compare the bacterial communities in PM2.5 and PM10 before and after disinfection.

A variety of pathogens and opportunistic pathogens such as Staphylococcus, Streptococcus, Corynebacterium, Bordetella, Pseudomonas, and Shewanella were detected, the quantities of which were noticeably reduced but not eradicated after disinfection. In addition, the impacts on several pathogens and opportunistic pathogens in PM2.5 were not significant, which may be due to bacterial resistance to this type of disinfectant or other reasons discussed in the present study.

Our results suggest that disinfection measures were effective in decontaminating air and further improving the feeding environment. This finding will help develop a reasonable disinfecting scheme for broiler houses.

Campylobacter is recognized as a major cause of foodborne gastroenteritis in humans in many countries and may be transferred from animals to humans. The consumption of chicken meat is identified as a major cause of Campylobacter infection in humans.

To find out the contamination rate of chicken meat with Campylobacter, the antimicrobial resistance (AMR) pattern, and the virulence-associated genes of theisolates.

Ninety packed chicken meat from 7 main poultry slaughterhouses in Shiraz were analyzed for Campylobacter spp. isolation through microbiological methods. Specific primers were used for the identification of the Campylobacter isolates on species level by polymerase chain reaction (PCR). Antibiotic resistant profiles were determined using the disc diffusion method based on Clinical and Laboratory Standards Institute (CLSI) standards. All the isolates were screened for 7 virulence-associated genes, namely cdtA, cdtB, cdtC, cadF, pldA, cgtB, and virB11 by PCR.

Out of 90 chicken meats, 26 (28.9%) Campylobacter spp. have been isolated. Resistance to ciprofloxacin (CIP), nalidixic acid (NA), and cefixime (CFM) was observed in all the isolates. Resistance to trimethoprim/sulfamethoxazole (SXT), tetracycline (TET), ampicillin (AMP), and chloramphenicol (CHO) was 80.8%, 88.5%, 76.9%, and 30.8%, respectively. Multidrug resistance (MDR) phenotype was observed in 80.8% of the Campylobacter isolates. All the isolates were positive for cdtA, cdtB, cdtC, and cadF genes. pldA and cgtB were detected in 65.4% and 15.4% of the isolates, respectively.

In this study, the presence of several virulence genes and an alarming level of MDR in Campylobacter spp. isolates were reported. Particularly, resistance to CIP and TET should be highlighted, since both are key drugs for the treatment of human campylobacteriosis.

Substance P (SP) is a neuropeptide that functions as a neuromodulator. It is released mainly in the brain stem and in nerve endings.

The present study aimed to provide fundamental data that may be applied to the assessment of pain in dogs by evaluating their serum SP concentrations.

Two groups of dogs were designated as pain groups that included 10 dogs with medial patella luxation (MPL) and 10 dogs with fractures, respectively, and 20 healthy dogs were enrolled as the control group.

The SP concentrations in the serum of the pain groups reached 485.5 ± 250.1 pg/ml that was significantly higher than those of the control group, which reached 116.4 ± 38.5 pg/ml. In particular, serum SP concentrations in dogs with fractures (663.3 ± 225.3 pg/ml) were significantly higher compared to those of dogs with MPL (307.8 ± 105.3 pg/ml), indicating that serum SP levels increased when the dogs experienced greater pain.

These findings propose the possibility that SP might be a useful biomarker for pain assessment in dogs. The present study may provide fundamental data that can aid in future pain management in dogs.

Researchers are challenged with identification of possible feed additives with the ability to increase the efficiency of feed utilization.

The present work aimed at studying growth pattern and carcass traits in broiler fed on dietary enzymes (Enzymex) and probiotic (Yeamark) over a period of six weeks.

A completely randomized design, including 8 treatments, 3 replications and 15 birds in each experimental unit was applied.

The results showed that feed intake decreased significantly (P<0.05) which might be due to the birds fulfilling their nutrient requirements by taking less amount of feed with improved digestibility of energy sources and amino acids. The results of present study also demonstrate the beneficial effects on performance and dressed yield in the treated groups in broiler.

Enzymes and probiotic are, therefore, suggested to be used as feed additives in broiler rations for higher profitability.

Among the birds, chicken was the model used in the majority of studies on germ cells and other birds like quail, turkey and pheasant had some interest but ostrich has been lacking from these researches.

The present study was conducted to confirm the presence of ostrich primordial germ cells (PGCs) in the embryonic blood and to determine the appropriate time for having them in the blood.

Embryos were extracted in embryonic day (E) 6-12, their blood was obtained and the rest of the embryos were processed for histological examinations. Staining by periodic acid-Schiff (PAS) method and immunohistochemistry (IHC) using stage-specific embryonic antigen 1 (SSEA1) and stage-specific embryonic antigen 4 (SSEA4) antibodies (Abs) were used for identification of the PGCs.

While the blood circulating ostrich PGCs were SSEA1-negative and SSEA4-positive, in the presumptive gonads PGCs showed negative immunoreactivity for both Abs. Although the ostrich PGCs were PAS-positive in both blood and presumptive gonad, their PAS-positive contents reduced during development from E 10 to E 12.

E 9, when the hind limb buds appear, is the best time for detecting PGCs in the ostrich embryonic blood.

Foot and mouth disease (FMD), which causes myocarditis, results in 50% sudden death in the suckling calves. Occurrence of arrhythmias associated with FMD induced myocarditis in calves is not reported hitherto. ‏‏‏The present work documents the arrhythmias associated with FMD in calf and their treatment using appropriate antiarrhythmic drugs. Case description: A three-month-old male Holstein Friesian crossbred calf naturally suffering from FMD was selected for the present study. Findings/treatment and outcome: Cardiac auscultation revealed grade 4 systolic murmurs and electrocardiography (ECG) showed sustained polymorphic ventricular premature complexes (PVPCs) with tachycardia on bipolar base apex lead. Apart from standard treatment, lidocaine 2% was administered at dose of 0.6 mg/kg intravenously over 15 min once a day and sinus rhythm was restored by 76 h post-treatment. Review of ECG and haematobiochemical examination revealed normal findings on 7th day of treatment.

The study demonstrates the presence of sustained PVPCs with tachycardia due to FMD induced myocarditis and the successful use of lidocaine in restoring the sinus rhythm and recovery of the calf.

Duck rearing is one of the important livelihoods of rural people. Duck plague is one of the diseases causing heavy mortality resulting in economic losses.

An outbreak of duck plague in a farm in Kadavakathi Village near Tenkasi, Tirunelveli Dt., is reported. Findings/treatment and outcome: Two thousands out of 4500 Chara-Chemballi breed of ducks which were recently purchased from Chenganacherry in Kerala died, with a mortality rate of 44.4%. Clinical signs of inappetence, partial closure of eyelid, conjunctivitis, corneal opacity, oculo-nasal discharge, soiled vent with green white watery diarrhoea, ataxia, incoordination and sudden death were observed. Necropsy examination revealed diphtheritic membrane in the oesophagus, congestion, petechial haemorrhages and multifocal gray white areas on the surface of the liver, epicardial haemorrhages, congested trachea, lung, kidneys, splenomegaly with mottled appearance and enteritis. Microscopical examination revealed presence of eosinophilic intranuclear and intracytoplasmic inclusions in the epithelial cells of the intestine and hepatocytes, degeneration and necrosis of enterocytes, dilated crypt epithelial cells with presence of eosinophilic intranuclear and intracytoplasmic inclusions, congestion and lymphoid cell depletion in the spleen, vasculitis, congestion, and haemorrhages in the trachea and lungs, proventriculitis, and congested kidneys. Polymerase chain reaction (PCR) also confirmed the duck plague viral infection by the amplification of polymerase gene fragment (446 bp).

Based on the above findings, the Chara-Chemballi duck disease outbreak was diagnosed as duck viral enteritis infection.