Haemophilus

• You can have too much of a good thing.
• The most important pathogens and the diseases they cause of livestock, companion animals, and wildlife should be listed.
• The basic characteristics of the most common pathogenic bacteria affecting domestic and wildlife animal species should be described.
• Bacterial virulence mechanisms, pathogenesis, and host response should be discussed.
• Clinical symptoms of specific bacterial diseases should be recognized.
• Clinical and laboratory data (e.g AST) should be interpreted.
• A differential diagnosis, treatment, and prevention plan for bacterial infections should be formulated.
• The most common zoonotic diseases should be discussed.
• The Pasteurellaceae family includes genera such as Haemophilus, Histophilus, Glaesserella, Avibacterium, Actinobacillus, Pasteurella, Mannheimia, and others.
• The least expensive and most appropriate drugs should be used.
• Antimicrobial resistance can occur and may need a susceptibility test.
• A. paragallinarum causes Fowl coryza, which affects birds only.
• Outer membrane protein preps or exopolysaccharideTreatment is susceptible to most antibiotics.
• H. somni is associated with TME, pneumonia, myocarditis, abortion, arthritis, which affects bovines and occasionally sheep.
• G. (H.) parasuis is associated with Glasser’s disease, pneumonia, septicemia, which affects pigs only.
• Case reports, characteristics, hosts, specific diseases, virulence properties, host immunity and vaccines, diagnosis and treatment of Pasteurellaceae should be discussed.
• Thirty pigs (of 60) ~ 4 weeks of age were ill following transportation in the cold in an open truck.
• Clinical symptoms of the pigs included sudden onset, high fever, lameness, depression, anorexia, some joints swollen, some nervous system symptoms, and labored breathing and coughing.
• Meningitis was present in several pigs, with muscular tremors, paralysis, and convulsions.
• Most untreated animals died 2-4 days after onset of symptoms; survivors were stunted and lame.
• Necropsy revealed sero-fibrinous pleuritis, pericarditis, peritonitis, and turbid joint fluid in some.
• One pig had fibrino-purlent meningitis.
• Haemophilus is a Gram-negative coccobacillus that is weakly fermentative and requires blood or blood factors.
• Each species of Haemophilus is host specific and the taxonomy is in a state of flux.
• Fowl Coryza, or acute rhinitis, is a disease of chickens characterized by inflammation of the turbinates and sinus epithelium, air sacculitis, and high morbidity but not mortality.
• Histophilus somni colonies are yellow when picked up with a white swab.
• A virus is a possible etiologic agent of the outbreak, along with Pasteurella multocida, Mannheimia haemolytica, Histophilus somni, and any or all of the above.
• The reasons for dissemination of Histophilus somni are not clear, but it is probably due to inflammation of the endothelium, with stress and viral infection required.
• Specific diseases due to Histophilus somni include inflammation of the air sacs, swollen sinuses, and inflammation of the turbinates and sinus epithelium.
• Vaccination against paragallinarum involves bacterins to serotypes A, B, and C, designed to raise antibody to cell components.
• Histophilus somni has a high morbidity but not mortality.
• Histophilus somni includes Haemophilus somnus, Hagni, and Histophilus ovis, and is specific for bovines and sheep, requiring neither X or V factor, but does require blood and CO2.
• Compromising factors of paragallinarum include viral or mycoplasma infection and stress, with disease primarily due to host inflammation.
• The normal habitat of Histophilus somni is the ruminant genital and respiratory tracts, and it disseminates via the bloodstream and localizes at other sites such as the brain, heart, joints, etc.
• Histophilus somni is primarily a feedlot disease.
• Immunity to paragallinarum is usually mediated by antibodies to capsule, with protective antibodies also made to LOS, membrane proteins, and other somatic antigens.
• Paragallinarum has virulence properties such as a capsule, lipooligosaccharide, adherence factors, and membrane proteins, but not exotoxins.
• Paragallinarum is specific for avian species and requires V factor only.
• Haemophilus spp and their host include Avibacterium (H.) paragallinarum, Glaesserella (H.) parasuis, Histophilus (H.) somni, and other species of less importance such as H. influenzae, H. felis, H. haemoglobinophilus, and Taylorella equigenitalis.
• Glasser’s Disease (polyserositis) usually occurs in young pigs and is characterized by fibrinous inflammation of serous surfaces.