title: Immunohistochemical detection of Haemophilus parasuis serovar 5 in formalin-fixed, paraffin-embedded tissues of experimentally infected swine.
abstract: An avidin-biotin complex immunohistochemistry technique was developed to detect Haemophilus parasuis serovar 5 in experimentally infected 18-21-day-old conventional pigs, using a rabbit polyclonal antiserum. Seven of 10 intratracheally inoculated animals developed a low to medium degree of fibrinous polyserositis; meninges and pleura were the most severely affected areas. Haemophilus parasuis was recovered from 9 of 10 pigs; in 2 of them H. parasuis was isolated from tracheal swabs only. Positive immunohistochemistry results, mainly observed as free bacteria or bacteria within inflammatory cell cytoplasm in the fibrinopurulent exudate, were observed in 8 of 10 animals. Cross-reactivity with Actinobacillus pleuropneumoniae was detected but not with other gram-positive and gram-negative bacteria tested. This immunohistochemistry technique seemed to be at least as sensitive as microbiologic cultures and could be useful in studies of pathogenesis and retrospective diagnosis. However, cross-reactivity with A. pleuropneumoniae means that positive immunohistochemistry results in lung tissue from field cases would be dubious.
authors.affiliation: U.D. Anatomia Patològica, Facultat de Veterinaria, Universitat Autònoma de Barcelona, Bellaterra, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Segalés
authors.forename: M
authors.initials: M
authors.lastname: Domingo
authors.forename: G I
authors.initials: GI
authors.lastname: Solano
authors.forename: C
authors.initials: C
authors.lastname: Pijoan
mesh_terms: D000818:Animals; D000906:Antibodies; D001996:Bronchopneumonia / Q000473:pathology / Q000662:veterinary*; D005557:Formaldehyde; D006190:Haemophilus / Q000145:classification / Q000302:isolation & purification*; D006192:Haemophilus Infections / Q000473:pathology / Q000662:veterinary*; D007124:Immunoenzyme Techniques; D007150:Immunohistochemistry / Q000379:methods; D010232:Paraffin; D011817:Rabbits; D013552:Swine; D013553:Swine Diseases
chemical_list: D000906:Antibodies; D005557:Formaldehyde; D010232:Paraffin