Serotyping of chlamydial clinical isolates from birds with monoclonal antibodies.

Forty-nine avian chlamydial strains, isolated mainly from various regions in France and from different species of birds, were analyzed and tested with a panel of nine monoclonal antibodies (MAbs) by the indirect microimmunofluorescence test (MIF). The MAbs included five serovar-specific MAbs, three MAbs raised against Chlamydia psittaci and Chlamydia pecorum ovine strains, and one genus-specific MAb. Of the 49 isolates, 41 came from parrots or budgerigars; the rest were from pigeons, a canary, a duck, and a dove. Two additional strains were from unknown hosts. Most of these avian strains were successfully serotyped according to their reactions with five serovar-specific MAbs by the MIF test. The serovars of 44 strains were determined: 39 were of serovar A, 3 of serovar B, and 2 of serovar E. The remaining five isolates were unclassified because they did not react with any of five serovar-specific MAbs but did react with genus MAb or the MAbs produced with ovine strains. The five unclassified isolates (two from budgerigars, two from Gabon gray parrots, and one from a duck) indicate that one or more additional serovars of C. psittaci exist in birds. The heterogeneity within each subgroup was evident because the 49 avian isolates gave 10 subgroups when the results of the five serovar-specific MAbs were combined with results from the three MAbs produced with ovine strains. This heterogeneity of the serovar isolates, as shown by the combination of MAbs, could provide strain markers very useful for epidemiologic studies.

[Infection by avian chlamydiosis in breeding pigeons in New Caledonia]. / Infection par la chlamydiose aviaire chez les pigeons d'élevage en Nouvelle-Calédonie.

An epidemiological survey on avian chlamydiosis, carried out by serological probing in 8 pigeon breeders representative of New Caledonian livestock, combined with bacteriological research on pigeon organs and droppings was set up in New Caledonia in order to determine the prevalence rate of this infection and to adapt sanitary regulations concerning pigeon imports. All sera collected (230) were analysed by complement fixation test (CFT). The organs were diluted in sucrose solution, then stored frozen (-70 degrees C), until inoculation of the yolk-sac of 3 6-8-day-old embryonated eggs (2 blind passages). Yolk-sac smears stained according to the Gimenez method were made in order to detect intracellular chlamydial organisms. Seventeen sera out of 230 were found to be positive, ie 7.4% of the test sample (confidence interval to 95% = 4.0 to 10.8%). The carrier pigeons were significantly more infected (17.8%) than pigeons of other breeds in New Caledonia. These results resulted in the sanitary authorities easing restrictions on imports of seropositive pigeons by imposing a 45-day compulsory quarantine with daily administration of chlortetracycline at the rate of 150 mg per 1 of drinking water.

Biotinylated probes to detect Leptospira interrogans on dot blot hybridization or by in situ hybridization.

Total genomic biotinylated probes which can identify leptospires by hybridization on filters or by in situ hybridization are described in this study. According to the weak G + C content of the strains studied (35-39%) and owing to the decreasing melting temperature (Tm) due to overbiotinylation, hybridization and wash temperatures were optimized at 33 degrees C and at 42 degrees C respectively. Fourteen serovars of Leptospira interrogans belonging to 11 different serogroups and three serovars of Leptospira biflexa were used in this study. Cross-hybridization results show that it is possible, by means of such probes, specifically to recognize pathogenic strains. These probes did not hybridize with the three saprophytic strains: L. buenos-aires, L. patoc and L. andamana. We also ran a total genomic probe, specific to the serovar buenos-aires which hybridizes only with homologous DNA.

Respiratory disease (rhinotracheitis) in turkeys in Brittany, France, 1981-1982. I. Field observations and serology.

During the summer of 1981, a respiratory disease epidemic occurred in turkeys in Brittany, France. Since this initial epizootic, which lasted through fall, epizootic waves similar to the initial one have occurred at approximately 6-month intervals, with smaller peaks at 2-month intervals. The epidemiology, clinical signs, and postmortem findings were highly suggestive of an epizootic of chlamydiosis. Serological tests for chlamydia, paramyxoviruses, avian influenza, adenovirus 127, mycoplasma, and Alcaligenes faecalis were conducted. The chlamydia tests were the only ones consistently positive.

[Experimental paratuberculosis: biological diagnosis in calves inoculated with strains of mycobactin-dependent mycobacteria]. / Paratuberculose expérimentale: diagnostic biologique chez des veaux inoculés avec des souches de mycobactéries mycobactine-dépendantes.

During an experiment on the pathogenicity of mycobactin-dependent mycobacteria strains for calf, the kinetics of antibody formation during infection was studied. The progress of cellular immunity was followed by examining delayed hypersensitivity using four allergens (bovine tuberculin HCSM, avian tuberculin HCSM, avian tuberculin PPD, and johnin PPD), and that of humoral immunity using complement fixation test and ELISA. Simultaneously, the elimination of bacilli in the faeces was examined. The excretion of bacilli, although intermittent, appeared to be the most demonstrative proof of infection: it could be shown at any stage of the disease. On the contrary, the delayed hypersensitivity using the avian tuberculin, and the serologic tests (the complement fixation test and ELISA), were positive only at defined periods of the disease: hypersensitivity reactions developed earlier than humoral reactions. The results obtained during these experiments confirmed that the mycobactin-dependent strains of "wood-pigeon" mycobacteria caused a disease in calves similar to the disease caused by Mycobacterium paratuberculosis.

[Results of a serological survey made in France (Vendeé region) in domestic ducks]. / Resultats d'une enquete serologique effectuee en France (vendee) Chez le canard a rotir.

The sera of domestic ducks were examined for antibodies to several infectious agents of palmipeds during the winter of 1982 in the abattoirs in la Vendée, an important region of duck production in the West of France. The performance of each batch and their antecedents was also studied. In Barbary ducks and crossbred ducks (from male wild ducks and female domestic ducks), antibodies were found to the virus of egg drop syndrome 16 (EDS 76), to Newcastle disease virus (NDV), to duck hepatitis virus and to chlamydia psittici. In Nantais ducks (resulting from a cross between Khaki Campbell and Pekin ducks), antibodies were detected against EDS 76 virus, duck hepatitis virus and chlamydia. The frequency and levels of antibodies varied between types or strains of ducks. About 50% of the Barbary ducks had high levels of antibodies to EDS 76 virus, whereas 70 to 80% of crossbred and Nantais ducks had these antibodies but at very low levels. Virtually 100% of Barbary ducks had high levels of antibodies against Derzsy's disease virus whereas only 10% of the batches of crossbred ducks had antibodies at varying levels. The proportion of batches with antibodies against NDV was higher in crossbred ducks (25%) than in Barbary ducks (2%) and the titres were low. Antibodies to duck hepatitis virus, when present, were of a high titre irrespective of type or strain of duck. Infection by chlamydia was suspected in 3% of lots of Barbary ducks, in 33% of lots of crossbred ducks, and in 3.7% of lots of Nantais ducks. These findings are discussed and considered in relation to breeding history and performance of the flocks. The EDS 76 virus could in certain circumstances cause weight loss in male Barbary ducks. These epidemiological observations need to be confirmed experimentally.

[Comparison of counterimmunoelectrophoresis with standard serological tests in the diagnosis of ovine brucellosis]. / Comparaison entre électrosynérèse et épreuves sérologiques classiques dans le diagnostic de la brucellose ovine.

Sera from 30 sheep experimentally infected and from 126 others with chronic brucellosis were comparatively studied by serum agglutination (SA), complement fixation (CF), rose bengal (RB), and counter-immunoelectrophoresis (CIEP) test. Standard serological tests, particularly SA and RB, essentially detect antibodies against cell-wall fractions of Brucella (LPS), whereas CIEP responds to intracellular antigens. Antibodies involved in this test appear late but remain a long time in the sera. CIEP is therefore recommended for screening of animals with chronic brucellosis in which SA and often CF and RB tests too negative.

[Immunization of ewes against experimental Brucella melitensis infection: comparison of eleven vaccines]. / Immunisation de la brebis contre l'infection expérimentale à Brucella melitensis: comparison de onze vaccins

A comparative study of 11 antibrucellic vaccines has been carried out in the Limousin region of 360 ewe-lambs divided into groups of 30, a 12th group serving as control. After being vaccinated at 8 months, the ewe-lambs were covered between 9 1/2 and 10 1/2 months, then infected at 11 months with Br. melitensis strain 53 H 38 by instillation of 4 x 10(6) germs on the conjonctiva. Six of these vaccines reduced the number of abortions and the excretion of brucella at parturition: three consisted of an inactivated suspension of a virulent S strain of Br. melitensis in oily adjuvant, another consisted of an inactivated suspension of a modified non-agglutinogenic strain of Br. melitensis also in oily adjuvant, the fifth was prepared from Br. melitensis H 105 and Br. abortus B 112 with saponin and the sixth from a strain of Br. melitensis modified with aluminium hydroxide as adjuvant.

[Serologic diagnosis of bovine and ovine brucellosis by a buffered antigen test]. / Le diagnostic sérologique de la brucellose bovine et ovine par l'épreuve à l'antigène tamponné

In the first part the authors compare the results of the test effected by means of a buffered antigen (EAT) whose cellular concentration was about 10%, with those of slow seroagglutination (SAW) and complement fixation (FC). Like the complement fixation, the buffered antigen test is more specific than seroagglutination. On the other hand, with such an antigen concentration the test lacks sensitivity. In the second part the authors compare the results obtained by these three tests--but this time utilizing a buffered brucella antigen of cellular concentration of approximately 5%--on bovines and ovines whose infection had been determined bacteriologically. The authors have established, under these conditions, that the buffered brucella antigen test allows the screening of a greater number of infected animals than does the SAW or even the FC. Both for bovines as well as ovines, the agreement between SAW and EAT equals 89%; betueen FC and EAT it reaches 93%; in case of disagreement it is always the EAT which is positive.