Use of deep nasopharyngeal swabs as a predictive diagnostic method for natural respiratory infections in calves

Abstract

BOVINE respiratory disease (BRD) in calves is a multifactorial disease complex involving interactions between a wide range of pathogens, immune status and environmental stresses. The most common non-viral pathogens involved include Mannheimia (Pasteurella) haemolytica, Pasteurella multocida, Histophilus somni (Haemophilus somnus) and Mycoplasma bovis (Bryson 2000, Donachie 2000, Nicholas and Ayling 2003. To ensure effective treatment of disease, veterinarians and researchers regularly need to determine the presence and antimicrobial sensitivity of pathogenic bacteria during outbreaks of BRD on farms and in clinical studies. Ideally, the technique should be quick and simple, and involve minimal stress for the calf. The ability to sample entire groups of animals and monitor infection status over time is also valuable and would be facilitated by the use of a simple nasopharyngeal swab method compared with the more difficult and hazardous procedures such as transtracheal aspiration or bronchoalveolar washings. This short communication describes the use of a deep nasopharyngeal swab technique to predict the presence of specific pathogenic species in the lower respiratory tract. Isolates were tested to determine their sensitivity to tulathromycin, a member of the newly developed triamilide subclass of macrolide derivatives (Letavic and others 2002). The study was conducted under veterinary supervision and in accordance with good clinical practice guidelines (Anon 2000), and the husbandry of all animals was in accordance with local animal welfare requirements and legislation.Thirty-seven beef calves, approximately four to six months of age, were group-housed on straw in an open-fronted barn in France, when a natural outbreak of BRD occurred. The criteria for enrolment in the study were those usually applied for the initiation of antimicrobial therapy, that is, the presence of clinical signs of BRD as defined by an elevated rectal temperature (≥40°C), together with abnormal respiratory signs (increased rate and/or abnormal character) and a depressed demeanour. Within the group, 20 animals met the criteria and were enrolled, which ensured a similar severity of disease among all the enrolled animals. The remaining calves were not enrolled but remained on the premises and were treated later for BRD with appropriate medication, if required, including antimicrobials.Nasopharyngeal samples were collected from each animal enrolled in the study, using sterile equine uterine culture swabs, 76 cm long, guarded by an external sheath and with the swab tip protected by a gelatine plug (Equi-Vet; Krusse). The animal's head was restrained by an assistant and the external nares were wiped clean of discharges. The distance between the nostril and the medial canthus of the eye was estimated and marked by the operator gripping the swab sheath at this point. The guarded, sheathed swab was then inserted into the nasal cavity as far as permitted by the position of the hand holding the swab. The tip of the swab was extruded beyond the sheath a...

Control, Management, and Prevention of Bovine Respiratory Disease in Dairy Calves and Cows

“…Genotypic analysis of matched isolates from nasopharyngeal swabs and lung lavage shows high degrees of similarity, demonstrating that the presence of bacteria on nasopharyngeal swabs is highly representative of lung etiology. 68 These results were obtained on clinical animals selected as described, and similar results would likely not be seen without appropriate case selection.…”

Relationship between nasopharyngeal and bronchoalveolar microbial communities in clinically healthy feedlot cattle

“…Following physical examination, a single, deep NPS was collected from each calf, using a 33-in.-long double guarded PVC culture swab (Kalayjian Industries, Inc. U.S.A.) according to published techniques [20]. Briefly, the calf’s nostrils were cleaned with a disposable wipe before collection.…”

Calf health from birth to weaning. III. housing and management of calf pneumonia

“…Nasal swabs should only be used to identify upper respiratory tract viruses [79]. Deep nasopharyngeal swabs, positive for M. haemolytica and M. bovis, have been demonstrated to be representative of isolates present in the lungs [80]. Samples obtained from transtracheal wash and/or bronchoalveolar lavage (BAL) can be used for virology, bacteriology, cytology and parasitology [79].…”