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Evaluation of specific gamma interferon responses and serology before and after a single intradermal skin test in cattle co-infected naturally with M. paratuberculosis and experimentally with M. bovis.. 5th International Scientific Conference 'One Health: Zoonoses - emerging threats' Med-Vet-Net 2017

L'effet systémique des adultes et nymphes d'Amblyomma variegatum sur la pathogénie d'infections expérimentales avec Dermatophilus congolensis a été étudié. Trois groupes de 4 moutons ont été utilisés, tous infectés avec des doses titrées identiques de D. congolensis. Un des groupes a été infesté simultanément par des adultes d'A. variegatum, le deuxième groupe par des nymphes, et le troisième comprenait les témoins non-infestés. L'évaluation des infections indique que l'effet systémique de la tique est limité aux adultes. Des tests cutanés et sérologiques utilisant d'autres antigènes ont montré une réduction significative des réponses immunitaires cellulaires et humorales uniquement chez les moutons infestés par les tiques adultes.

Dermal allergic test reagin was prepared by cultivating local strain of Histoplasma farciminosum isolates. Standardized antigen dilution of 1: 100 was used. A volume of 0.2ml of the preparation was injected intradermally in the caudal cervical area. Stratified random sampling was used in the selection of horses. Accordingly a local elevated induration at the injection site of greater than 6mm 48-72hrs post injection was considered positive. Most reactors revealed convex type of induration while three horses showed diffused swelling. Some chronic cases did not react to the test precipitating the development of anergy.

Egg belongs to the list of ingredients that must be labeled because of its frequent involvement in food allergies especially in childhood. Several thermal processes are commonly applied to egg and it is known that some egg-allergic people can tolerate well-cooked egg. Food allergens are characterized by their ability to elicit IgE antibodies (sensitization) in susceptible individuals and to display several IgE-binding epitopes. Allergenic potential influenced by different structural levels (sequence, 2D/3D structures as well as supra-molecular organization) can be greatly impacted by all modifications of these structures due to processing. Our work aimed to analyze the impact of pasteurization and boiling of egg and its fractions on in vivo reactivity and its relation to IgE-binding profiles to egg allergens/fractions in a cohort of children allergic to egg. Allergic children (n=52, 18 months - 7 years old) were recruited, all had positive skin prick-tests (SPT) to raw whole egg and egg white and 80% to raw egg yolk. Reactivity to pasteurized and boiled fractions was evaluated by SPT. Sera samples taken at inclusion were used to draw profiles of IgE-reactivity against known allergens and proteins of egg white and against fractions of egg yolk by ELISA. Relative STP data and IgE-binding profiles were analyzed by hierarchical classification to evidence typical profiles of reactivity in this cohort. Pasteurization had very limited impact on structure of egg and only 10% and 5% of children STP became negative with pasteurized (66°C, 6 min) whole egg or egg white. Boiling (100°C, 10 min) greatly changed structure of egg products and had a higher effect than pasteurization since 55%, 27% and 67% of children SPT remained positive to boiled egg and yolk and white fractions. Two typical STP behaviors were evidenced by classification in this cohort. IgE-binding profiles largely differed among children but three typical profiles where extracted from data. Contingency analysis revealed links between typical STP and IgE-binding profiles with possible explanation of tolerance to cooked egg.