Livestock Microbial Diseases

Transcription

1 Actinobacillosis DISEASE Actinobacillus spp. (Gram negative, facultative anaerobes) A. lignieresii - wooden tongue A. equuli - sleepy foal disease A. pleuropneumoniae porcine pleuropneumonia A. seminis - epididymitis in rams A. rossi abortion in pigs May cause pyogranulomatous lesions in various organs (especially oral cavity and forestomachs), neonatal septicaemia, abscesses, metritis, abortion, epididymitis, orchitis and genital tract infections in the different animal species Actinomycosis Actinomyces bovis Causes lumpy jaw pyogranulomatous osteomyelitis of mandible and sometimes maxilla in cattle. Lesser importance in horses. Anthrax Bacillus anthracis Atrophic Rhinitis Pasteurella multocida Type D alone or in combination with Bordetella bronchiseptica. (Gram negative, facultative anaerobe and aerobe) Subclinical infections are common and detection/removal of carriers is crucial Pathology: In live animals collect biopsies from abscesses or affected tissues and, in dead animals, a full set of organ samples * should be collected into10% buffered formalin to exclude other differentials. Bacteriology: Swabs or fresh samples from pyogranulomas, fistulae, abscesses, exudates, secretions or affected organ samples in septicaemias. A. lignieresii collect samples from oral cavity and gastrointestinal tract lesions. A. equuli collect blood and kidney. A. seminis collect testis and semen. A. pleuropneumoniae collect lung (caudal lobes preferably), tonsillar tissues, mediastinal lymph nodes, joint fluid and nasal secretions. Serology: CFT and ELISA for A. pleuropneumoniae. Molecular Biology: PCR for A. pleuropneumoniae (e.g. tonsillar tissue, respiratory tissues). Other Tests: Gram stained impression smears of lesions. Pathology: Typical macroscopic and histological lesions of pyogranulomatous osteomyelitis of mandible and sometimes maxilla. Target tissues for formalin fixation include mandible and affected tissues. In dead animals a full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Fresh samples or swabs in transport medium from mandible and affected tissues for anaerobic culture. - Controlled disease Pathology: Typical macroscopic and histological lesions of turbinate atrophy and facial deformity. Collect fresh snouts for lesion scoring and histopathology. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Swabs or fresh samples for culture of toxigenic P. multocida strains. Tonsils are the samples of choice. Fresh nasal swabs or tissues for isolation of B. bronchiseptica Serology: Serum samples for ELISA to detect the presence of P. multocida toxins. Serum samples to demonstrate the presence of antibodies against B. bronchiseptica. Molecular Biology: Swabs or fresh samples for PCR to confirm the presence of toxigenic strains of Pasteurella multocida type D. Tonsils are the samples of choice. Fresh nasal swabs or tissues for species-specific identification of B. bronchiseptica. 280

2 Bacillary Haemoglobinuria Clostridium novyi Type D Sheep, pigs and horses Has not been diagnosed in SA Pathology: Typical macroscopic and microscopic lesions associated with severe icterus, haemoglobinuria, haemoglobinuric nephrosis, hepatic degeneration and foci of necrosis, and toxaemia. Target tissues for formalin fixation include liver, kidney and spleen. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Anaerobic culture of affected liver, kidney and spleen (fresh organs or swabs with anaerobic transport medium). Also include ml of pleural, pericardial and peritoneal fluids and urine. Molecular Biology: PCR identification of C. novyi in fresh, formalin fixed and culture samples as above. Besnoitiosis Besnoitia bennetti Bovines, rarely equids Black Disease Clostridium novyi Type B Sheep, cattle and occasionally horses and pigs Associated with migrating immature liver fluke in ruminants Blackleg (Blackquarter or Sponssiekte) Clostridium chauvoei Other tests: Fluorescent antibody test (FAT) of impression smears for the identification of C. novyi in liver samples. Collect at least six smears. Pathology: Typical macroscopic and histological lesions of anasarca, chronic scleroderma and orchitis. Collect samples from these affected organs (skin and testis) in formalin. A full set of organ samples * should be collected into10% buffered formalin to exclude other differentials. Other Tests: Examination of conjunctival smears or formalin fixed biopsies for the presence of cysts. Pathology: Typical lesions may be seen on macro- and micropathology including cyanosis and blackish discouloration of subcutis, hepatic necrosis, fibrinous peritonitis, ascites, hydrothorax, hydropericardium and subcutaneous oedema of ventral thoracic wall. Target tissues for formalin fixation include liver, kidney and spleen. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Anaerobic culture of affected organs (liver, kidney, spleen), subcutaneous tissues and exudates (fresh organs or swabs with anaerobic transport medium). Also include ml of pleural, pericardial and peritoneal fluids and urine. Molecular Biology: PCR identification of C. novyi in fresh, formalin fixed and culture samples as above. Other tests: Fluorescent antibody test (FAT) of impression smears for the identification of C. novyi in tissue samples. Collect at least six smears. Pathology: Typical lesions of subcutaneous, intermuscular and interstitial oedema to necrohaemorrhagic gangrenous myositis and cellulitis with rancid odour and crepitation. Collect affected skeletal muscles (hindquarters or any other affected muscle group need to search carefully as there may only be small focal lesions such as in the tongue and crura of the diaphragm), subcutis or internal organs (e.g. heart pluck) into 10% buffered formalin. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Cattle Bacteriology: Anaerobic culture of affected muscles, organs, subcutaneous tissues and exudates (fresh organs or swabs with anaerobic transport medium). Molecular Biology: PCR identification of C. chauvoei in fresh, formalin fixed and culture samples. Other tests: Fluorescent antibody test (FAT) of impression smears for the identification of C. chauvoei in tissue samples. Immunoperoxidase staining technique for the identification of C. chauvoei in formalin fixed tissues. 281

3 Bolo Disease Corynebacterium spp. (Gram positive, facultative anaerobes) Bordetella bronchiseptica Infections (Gram negative, aerobe) Pigs atrophic rhinitis Pathology: Typical lesions of localised, mild, subacute to chronic, superficial dermatitis may be seen on macro- and micropathology. Skin biopsies should be collected into 10% buffered formalin. Bacteriology: Culture of sterile swabs from dry skin and fleece. Pathology: Typical macroscopic and histological lesions of atrophic rhinitis - turbinate atrophy and facial deformity. Collect fresh snouts for lesion scoring and formalin fixed samples for histology. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Fresh nasal swabs or tissues for isolation of B. bronchiseptica. Serology: Serum samples to demonstrate the presence of antibodies against B. bronchiseptica (where available) Borrelia suilla (Gram negative, microaerophile) Pigs little economic importance in SA Borrelia theileri (Gram negative microaerophile) Molecular Biology: Fresh nasal swabs or tissues for species-specific identification of B. bronchiseptica. Pathology: Typical lesions of ulcerative granulomata may be seen in the skin, subcutaneous tissues and testis on macro- and micropathology. Collect biopsies of lesions or affected skin, subcutis and testis during slaughter/post mortem into10% buffered formalin. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Other tests: Spirochaetes are easily observed in fresh tissues and stain well with Giemsa and Gram stains. Dark field microscopy may also be used. Pathology: Non-specific lesions on macro- and micropathology. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. May affect cattle, sheep and horses of little economic importance Botulism Clostridium botulinum Groups I, II, III and IV Toxin types A-G Brucellosis Other tests: Spirochaetes are easily observed in blood smears and stain well with aniline dyes. Pathology: Non-specific lesions on macro- and micropathology. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Anaerobic culture of rumen, small intestinal, caecal, colon and rectal content samples as well as possible sources of infection e.g. feed, water, bedding, soil etc. Serology: Antibodies against certain toxins may be demonstrated with an ELISA on serum samples. Molecular Biology: Toxin genes may be demonstrated by means of a PCR (where available) in intestinal, faecal, serum and food samples. Other Tests: A live mouse bioassay may be performed on faecal, serum, gastrointestinal, food and water samples to identify botulism toxin. - Controlled Disease Brucella spp. (Gram negative, aerobe and capnophile) 282

4 Campylobacter jejuni (Gram negative, microaerophile) Sheep abortion, enteritis Cattle mastitis, abortion, enteritis Goats abortion Caseous Lymphadenitis Corynebacterium pseudotuberculosis Sheep and goats - caseous lymphadenitis. Less commonly pneumonia, hepatitis, mastitis, arthritis, orchitis, subcutaneous abscesses, abortion, stillbirths, perinatal mortalities. Haemolysis and icterus following infection/vaccination Cattle ulcerative lymphangitis Horses - ulcerative lymphangitis, pectoral abscesses, contagious acne, mastitis and abortion Chlamydiosis Chlamydophila pecorum, Chlamydophila suis, Chlamydophila abortus Ruminants abortion (C. abortus), enteritis, pneumonia, arthritis, conjunctivitis, encephalomyelitis (C. pecorum) Pigs pneumonia, conjunctivitis, enteritis (C. suis) Pathology: Lesions of enteritis and mastitis may be seen on macro- and micropathology. Target tissues for formalin fixation include large intestine (cattle), small intestine (sheep) or affected mammary glands (cattle). A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Culture of affected intestines and gallbladder in chronically affected animals. Fresh milk samples from animals with subclinical and mild mastitis. Abortions - Please refer to Reproduction Bovine Abortion Investigation for sample collection Pathology: In live animals, target tissues for formalin fixation include samples from abscesses or any other lesions and, in dead animals, abscesses and all affected organs. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Fresh samples from abscesses or lesions in any of the affected organs. When sampling abscesses, the capsular wall or swabs from the inside of the capsular wall are preferred. Abortions - Please refer to Reproduction Bovine Abortion Investigation for sample collection Pathology: Target tissues for formalin fixation include intestine, lung, joint, conjunctiva and brain. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Isolation: Collect fresh samples from lesions and all affected organs, including target organs listed above. Molecular biology: Collect fresh samples from lesions and all affected organs, including target organs listed above. Serology: Paired and convalescent serum samples for CFT and ELISA may be attempted. Other tests: Direct staining of organisms or inclusions in various tissues and exudates. To be stained with various special stains and immunohistochemical techniques. Abortions - Please refer to Reproduction Bovine Abortion Investigation for sample collection 283

5 Coccidiosis Eimeria spp, Isospora spp Sheep, goats and cattle common (Eimeria spp) Horses rare Pigs Isospora suis not in SA Contagious Bovine Keratoconjunctivitis Moraxella bovis (Gram negative, aerobe) Contagious Bovine Pleuropneumonia Mycoplasma mycoides subsp. mycoides (SC) (Gram positive, microaerophile) Corynebacterium renale Group Infections Corynebacterium renale, Corynebacterium pilosum, Corynebacterium cystitidis (Gram positive, facultative anaerobes) Urinary tract infections in cattle and sheep Cryptosporidiosis Cryptosporidium spp Lambs, kids, piglets, foals and calves. Dermatophilosis Dermatophilus congolensis (Gram positive, aerobe and capnophile) Pathology: Necrohaemorrhagic enteritis (small intestine sheep and goats) with small, white foci on mucosal surface. Fibrinohaemorrhagic typhlocolitis and proctitis (cattle). Fibrinous to fibrinonecrotic enteritis of caudal small intestines (pigs). Target tissues for formalin fixation include affected large intestine (cattle), small intestine (sheep and pigs). A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Other tests: Fresh faecal samples from affected intestinal content for the demonstration of oocysts and oocyst counts. Pathology: Typical lesions of keratoconjunctivitis. Bacteriology: Corneal and conjunctival swabs in early infections and from untreated cases. Controlled disease Pathology: Typical lesions of cystitis, urethritis and pyelonephritis (cattle), ulcerative posthitis (bulls and adult wethers) and vulvitis (ewes). Collect samples from affected bladder and kidney into 10% buffered formalin. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Culture of urine in live animals and, renal pelvis, ureter or bladder in dead animals. Other tests: A fluorescent antibody test to differentiate between cystitis and pyelonephritis cases. Pathology: Non-specific gross pathology of enteritis with the presence of intralesional cryptosporidia in histological sections. Collect multiple sections of intestine into 10% buffered formalin. In addition, a full set of organ samples * should be collected into formalin to exclude other differentials. Other tests: Fresh faecal samples from affected intestinal content for the demonstration of cryptosporidial oocysts. Pathology: Typical skin lesions of exudative dermatitis with scab formation, thickening of the skin and alopecia. Skin biopsies should be collected into 10% buffered formalin for histopathology. Bacteriology: Fresh scabs or crusts, skin biopsies or swabs of skin lesions for culture and Gram staining. Sheep lumpy wool, strawberry foot rot Cattle Senkobo disease 284

6 Enterotoxaemia-Like Diseases (Pulpy kidney, lamb dysentery, struck, enterotoxaemia, yellow lamb disease, necrotic enteritis, haemorrhagic enteritis, sudden death, equine intestinal clostridiosis) Clostridium perfringens Types A, B, C, D, E Alpha, beta, beta2, epsilon and iota toxins Cattle, sheep, goats, pigs, horses Epididymitis in Rams Actinobacillus seminis, Actinobacillus actinomycetemcomitans, Histophilus ovis, Histophilus somni and Histophilus agni (Gram negative, facultative anaerobes, capnophiles) Erysipelas Erysipelothrix rhusiopathiae Escherichia coli Infections (Gram negative, facultative anaerobe) Enterotoxigenic infections (ETEC) Enteropathogenic infections (EPEC) Enterohaemorrhagic infections (EHEC) Shiga toxin producing infections (STEC) Necrotoxigenic infections (NTEC) Colisepticaemia Other less common syndromes - abortion, metritis, cystitis, mastitis, agalactia Pathology: Typical lesions seen on macro and micropathology which may include rapid putrefaction, septicaemia, necrohaemorrhagic to ulcerative enteritis (small and large intestines), nephrosis, hepatosis, splenomegaly, abomasitis and ulceration (cattle), typhlocolitis (horses), serous to blood tinged exudates in body cavities and pericardium, pulmonary congestion and oedema. Focal symmetric encephalomalacia in sheep (chronic pulpy kidney). Collect all affected organs as above, and brain in sheep (FSE) in 10% buffered formalin. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Anaerobic culture of affected tissues including intestines, liver, spleen and kidney. Serology: ELISA of culture supernatants and intestinal fluids for toxin identification. Molecular Biology: Toxin genes may be demonstrated by means of a PCR of culture isolates, ingesta or intestinal biopsy specimens (where PCR is available). Other Tests: Toxin neutralization tests in mice and guinea pigs using type A, B, C, D and E antisera. Microscopic examination of Gram-stained smears of affected tissues or intestinal mucosa. Glucosuria in sheep in pulpy kidney. Pathology: Macro- and micropathological lesions of acute to chronic epididymitis and orchitis. Collect samples from affected testis into 10% buffered formalin. Bacteriology: Fresh tissues or swabs from affected testis for culture. Notifiable disease - Pathology: Typical macro and microscopic lesions of enteritis (all species), oedema disease (pigs) and septicaemia (all species). Collect all segments of large and small intestines showing enteric lesions as well as mesenteric lymph nodes into10% buffered formalin. In colisepticaemia cases, collect blood, liver, spleen, kidney and brain. In the other less common syndromes, include formalin fixed affected organs (udder, genital tract and bladder). A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Collect fresh samples of all segments of large and small intestines showing enteric lesions as well as mesenteric lymph nodes. Collect samples from more than one animal and from untreated cases. In colisepticaemia cases, collect blood, liver, spleen, kidney and brain. Rectal swabs are less satisfactory but can be taken in live animals. In the other less common syndromes include fresh affected organ samples. Serotyping of isolates is recommended. Molecular Biology: Samples as for bacteriology. Genotyping of virulence genes. Abortions Please refer to Reproduction Bovine Abortion Investigation for sample collection 285

7 Foot Infections of Cattle, Sheep and Goats Fusobacterium necrophorum, Dichelobacter nodosus (Formerly Bacteroides) (Gram negative, anaerobes) Pathology: Confusing nomenclature but typical macroscopic and microscopic lesions can be seen affecting various anatomical regions of the foot. Collect samples from affected tissues into 10% buffered formalin. Bacteriology: Fresh tissues or swabs from affected areas for culture. Arcanobacterium pyogenes Gas Gangrene/Malignant oedema Clostridium septicum Ruminants, pigs and horses Pathology: Typical lesions of subcutaneous, intermuscular and interstitial oedema to necrohaemorrhagic gangrenous myositis and cellulitis. Collect affected skeletal muscles and subcutis in formalin. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Anaerobic culture of affected muscles, organs, subcutaneous tissues and exudates (fresh organs or swabs with anaerobic transport medium). Molecular Biology: PCR identification of C. septicum in fresh, formalin fixed and culture samples. Genital Campylobacteriosis Campylobacter foetus (Gram negative, microaerophile) Glanders Other tests: Fluorescent antibody test (FAT) of impression smears for the identification of C. septicum in tissue samples. Collect at least six smears. See section on Reproduction Bovine Venereal Diseases for sample collection - Controlled Disease Burkholderia mallei (Gram negative, aerobe) Glässer s Disease Haemophilus parasuis (Gram negative, facultative anaerobe, capnophilic) Greasy Pig Disease Pathology: Typical lesions include serofibrinous polyserositis, polyarthritis and meningitis. May cause acute septicaemia. Include formalin fixed samples from all affected target tissues. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Swabs or fresh meningeal exudate and cerebrospinal fluid are most effective. May be isolated from lungs but seldom from other organs. Pathology: Typical macroscopic and histological lesions of exudative epidermitis in pigs. Collect skin biopsies into10% buffered formalin. Staphylococcus hyicus subsp. hyicus Bacteriology: Culture of skin and enlarged superficial lymph nodes. 286

8 Haemorrhagic Bowel Syndrome Campylobacter spp. (Gram negative, microaerophiles) Haemorrhagic Septicaemia Pasteurella multocida Types B and E (Gram negative, facultative anaerobe) Asian form - Type B African form - Type E Hepatic Necrobacillosis Fusobacterium necrophorum (Gram negative, anaerobe) Common in cattle, less common in goats and sheep Can be part of mixed infection with Arcanobacterium pyogenes. Associated with rumenitis in cattle. Histophilus somnii Complex in Cattle (Gram negative, facultative anaerobe, capnophile) Pathology: Suggestive macroscopic and histological lesions of enteritis in large intestine (cattle) or ileum (lambs). Samples include formalin fixed portions of small and large intestine. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Fresh samples from large and small intestines or gall bladder in chronic affected animals. Pathology: Typical lesions of peracute to acute haemorrhagic septicaemia congestion and petecehiae and ecchymoses of serosal surfaces and subcutis, ascites, hydrothorax, hydropericardium, focal anasarca, hyperaemia at thoracic inlet, pulmonary oedema, bronchopneumonia, focal serofibrinous myositis, tracheal and peritracheal oedema and haemorrhages. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Blood or bone marrow samples from dead animals. Blood is rarely useful in live animals. Serotyping of isolates is recommended. Pathology: Typical lesions of hepatic abscessation, rumenitis, abomasal ulceration, traumatic reticulitis, pulmonary thromboembolism, pneumonia and abscessation, and endocarditis. Include all affected tissues in 10% buffered formalin. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Swabs or fresh tissues from hepatic abscesses or other affected organs. Bacteriology may be insensitive in chronic cases. Pathology: May cause lesions of septicaemia, thrombotic meningoencephalitis (TME), pneumonia, myocarditis, arthritis, mastitis, reproductive disorders (metritis, endometritis, cervicitis, vaginitis, infertility) and abortion. Include all affected tissues (e.g. lung, heart, entire brain, genital tract) as well as a full set of organ samples * into 10% buffered formalin to exclude other differentials. Bacteriology: Swabs or fresh tissues from all affected organs. Blood and cerebrospinal fluid in clinical cases have been shown to give inconsistent results in TME. Generally, bacteriology may be insensitive. Molecular Biology: PCR, where available, has been shown to be very sensitive on lung and bronchial swabs. Other Tests: IHC staining of formalin fixed tissues. Klebsiella Infections (Gram negative, facultative anaerobes) Cows and sows mastitis Calves and piglets septicaemia Other rare syndromes pneumonia, arthritis Abortions Please refer to Reproduction Bovine Abortion Investigation for sample collection. Pathology: Macroscopic and histological lesions of mastitis and septicaemia (young animals). Rarely, pneumonia and polyarthritis. Collect formalin fixed tissues from the affected organs. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Mastitis Swabs and fresh tissues from affected udder. Septicaemia - Swabs or fresh samples from affected organs (spleen, liver, lung). Serotyping of isolates is recommended. 287

9 Leptospirosis Leptospira interrogans serovars (Gram negative, aerobe) Listeriosis Listeria monocytogenes Causes meningoencephalitis, abortion/stillbirth or neonatal septicaemia. Refer to Disease Diagnostics Livestock Diseases for sample collection Pathology: Meningoencephalitis Macroscopically non-specific, histology more typical and mostly seen in brain stem area collect entire brain, including brain stem, and spinal cord in formalin for histology. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Abortions/stillbirths Please refer to Reproduction Bovine Abortion Investigation for sample collection. Neonatal septicaemia Lesions of multifocal necrosis/septicaemia in many organs. Collect formalin fixed samples of liver, spleen, lymph nodes, myocardium, lungs, adrenals, gastrointestinal tract and brain. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Subclinical carriers may secrete organism in faeces and milk. Lyme Disease Borrelia burgdorferi (Gram negative, microaerophile) Cattle, horses, small ruminants Melioidosis Burkholderia pseudomallei (Gram negative, aerobe) Cattle, sheep, goats, pigs, horses Not very important in SA. Bacteriology: Storage of samples at 4ºC for up to 2 months enhances the ability to culture the causative organisms. Culture samples to be collected for the different syndromes include: Meningoencephalitis brain stem. Abortions/stillbirths Please refer to Reproduction Bovine Abortion Investigation for sample collection. Neonatal septicaemia - affected organs, placenta, faeces, urine, blood and milk samples Pathology: Clinically ill defined but associated with skin rash, arthritis, myocarditis, abortions/stillbirths and anterior uveitis (horses). Macroscopic pathology and histology ill defined in domestic animals. Samples from affected tissues such as skin and joints should be collected in formalin. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Fresh tissues, swabs from blood, skin, milk, synovial- and cerebrospinal fluids should be collected for culture. Serology: Serum samples to be collected for ELISA antibody determination. Molecular Biology: Samples as for bacteriology. Pathology: Typical macroscopic and histological suppurating or caseous lesions in lymph nodes or other organs. Collect affected nodes or organs in formalin. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Fresh tissues or swabs from nasal exudates or abscess like lesions. Molecular Biology: Fresh tissues or swabs from nasal exudates or abscess like lesions for PCR. Serology: Serum samples to be collected for ELISA antibody determination. 288

10 Mycoplasmal Pneumonia of Pigs Mycoplasma hyopneumoniae (Gram positive, microaerophile) Mycoplasma hyorhinis, Mycoplasma hyosynoviae (Gram positive, microaerophile) Affects pigs less than 3 months of age Necrotic Rhinitis Pathology: Typical macroscopic and histological of chronic pneumonia and consolidation of mostly ventral aspects of cranial, accessory and middle lobes. Fibrinous to serofibrinous pleuritis. Collect affected lung lobes into 10% buffered formalin. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Fresh tissues or swabs from affected lung for culture. Culture is not always practical as the organism takes a long time to grow. Swine enzootic pneumonia Molecular Biology: Fresh tissues or swabs from lung lesions for PCR. Mycoplasmal Polyserositis and Arthritis of Pigs Pathology: Typical macroscopic and histological lesions of serofibrinous polyserositis affecting the pleura, peritoneum, pericardium and joints. Collect affected tissues into 10% buffered formalin. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Fusobacterium necrophorum (Gram negative, anaerobe) Porcine necrotic rhinitis/bull nose. Necrotic and Ulcerative Stomatitis Fusobacterium necrophorum (Gram negative, anaerobe) Bacteriology: Fresh exudates from body cavities or joints for culture. Pathology: Typical macroscopic and histological lesions of severe and asymmetrical irregular swelling and deformity of the snout. Include all affected tissues as well as a full set of organ samples * in 10% buffered formalin to exclude all other differentials. Bacteriology: Swabs or fresh lesions for culture. Pathology: Typical macroscopic and histological lesions of focal necrotic inflammation of the mucous membranes of the oral cavity, pharynx and larynx. Ulcers may develop. In a small percentage of animals, lesions may be seen in the trachea, nasal passages, oesophagus and forestomachs. Include all affected tissues from the oral cavity, as well as a full set of organ samples * in 10% buffered formalin to exclude all other differentials. Calf diphtheria, oral necrobacillosis. Calves, sheep, goats and pigs. Nocardiosis Nocardia asteroides (Gram positive, aerobe) Mastitis (cattle, goats), abortion (cattle, pigs, sheep, horses), corneal ulceration and chronic dermatitis (cattle), granulomatous disease/pneumonia (cattle, horses). Paratuberculosis/ Johne s Disease Mycobacterium avium subsp. paratuberculosis (Gram positive, aerobe) Bacteriology: Swabs, oral lesions and tissues from upper respiratory tract. Bacteriology may be insensitive in chronic cases. Pathology: Typical macroscopic and histological lesions of mastitis, abortion, corneal ulceration, chronic dermatitis, widespread granulomatous disease/pneumonia. Collect all affected organs in formalin. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Fresh tissues, swabs from affected organs or granulomatous lesions for culture. Other Tests: Gram staining of exudate smears to reveal the presence of organisms admixed with sulphur granules. Intradermal skin testing. Please refer to Reproduction Bovine Abortion Investigation for sample collection. Controlled Disease 289

11 Pneumonic Pasteurellosis Pasteurella multocida and Mannheimia haemolytica (Gram negative, facultative anaerobes) Forms part of the shipping fever, and the bovine respiratory disease complexes. Proliferative Enteropathy (PE) in Pigs Lawsonia intracellularis (Gram negative, obligate intracellular parasite, microaerophile) Pathology: Typical macroscopic and histological lesions of serofibrinous pleuropneumonia. Severe typical bronchopneumonia, commonly in the cranioventral lobes with consolidation; and grey, red and black hepatisation. Straw coloured fibrin rich lung oedema and intrathoracic fluid present. Fibrin adhesions to chronic fibrous lesion seen. Include samples from all affected lung and affected organs in formalin although a full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Culture of affected lung. Serotyping is recommended. Pathology: Typical macroscopic and histological lesion of porcine intestinal adenomatosis (PIA), proliferative haemorrhagic enteropathy (PHE), necrotic enteritis (NR) and regional ileitis (RI). Collect samples from affected intestinal sections in formalin combined with Warthin Starry staining of these tissues to demonstrate the presence of intralesional organisms. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Usually not successful. Serology: Serum samples for ELISA antibody determination. Molecular Biology: PCR and immunofluorescence tests on fresh faecal samples. Rhodococcus equi (Gram positive, aerobe) Cattle and pigs - granulomatous lesions in submandibular and other lymph nodes Goats - granulomatous lesions in liver with wasting and death Horses bronchopneumonia, arthritis, osteomyelitis, mesenteric lymphadenitis and ulcerative lymphangitis Other Tests: Staining of faecal smears with modified Ziehl-Neelsen technique to demonstrate bacteria. Pathology: Typical macroscopic and histological lesions of pyogranulomatous lymphadenitis usually mesenteric and bronchial lymph nodes (cattle) and submandibular lymph nodes (cattle/pigs). Granulomatous lesions in livers of goats. Collect affected nodes in 10% buffered formalin. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Transtracheal aspirates for culture in live horses. Swabs or fresh tissue specimens from any affected lymph node or liver with typical lesions in the other species. 290

12 Salmonellosis Salmonella spp. (Gram negative, facultative anaerobe) Cattle septicaemia, enteritis, abortion Sheep septicaemia, diarrhoea, abortion Pigs septicaemia, enterocolitis Horses septicaemia, enterotyphlocolitis, chronic diarrhoea, failure to thrive; rarely polyarthritis, orchitis, fistulous withers, abortion Salmonella Enteritidis is a Controlled Disease - Streptococcus porcinus Infections Pathology: Suggestive macroscopic and histological lesions. Rectal stricture seen in pigs. Collect affected small and large intestine, caecum, liver, spleen and mesenteric lymph nodes in formalin. A full set of organ samples * should be collected in 10% buffered formalin to exclude other differentials. Bacteriology: Live animals blood and rectal swabs. Rectal biopsies may be more sensitive than swabs. Multiple cultures may be required for confirmation of diagnosis as organisms are often shed intermittently. Dead animals mesenteric lymph node, liver, spleen and affected intestine. In horses always include ileocolonic lymph nodes, caecum and/or proximal large colon. Serotyping of isolates is recommended. Molecular Biology: Multiplex PCR to detect Salmonella spp. in shedding pigs. Samples similar as for bacteriology. Pathology: Typical macroscopic and histological lesions of abscessation of the lymph nodes of the head and neck. Include samples from all affected target organs and abscesses in formalin although a full set of organ samples * should always be collected, in formalin, to exclude other differentials. Abortion has been reported. Streptococcus suis Infections (Gram positive, facultative anaerobe) Bacteriology: Bacterial culture of pus from abscesses, and lung, liver, spleen and kidney in foetuses. Pathology: Typical macroscopic and histological lesions of septicaemia, meningitis, purulent arthritis, valvular endocarditis, bronchopneumonia, genital infections and abortions. Include samples from all affected target organs in formalin although a full set of organ samples * should always be collected, in formalin, to exclude other differentials. Bacteriology: Bacterial culture of brain, cerebrospinal fluid, blood, peritoneal and pleural effusions, internal organs, synovial membranes and fluid. Serotyping is recommended. Serology: Identification of organism by means of direct or indirect immunofluorescent antibody tests on smears. ELISA for the detection of antibodies against serotype 2. Swine Dysentery Brachyspira hyodysenteriae (Gram negative, anaerobe) Molecular Biology: Species-specific PCR. Pathology: Typical macroscopic and histological lesions of acute diphtheric to necrotic enteritis with haemorrhage of colon and caecum. Include samples from all affected target organs in formalin although a full set of organ samples * should always be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Faecal swabs, fresh faeces or fresh tissue samples from affected intestines for anaerobic culture. Serology: ELISA and microtitre agglutination to confirm infection on herd basis. Molecular Biology: PCR screen of samples as described above for bacteriology. Other Tests: Gram staining and direct FAT of faecal smears or intestinal samples. Faecal antigen ELISA for herd detection. 291

13 Swollen Head of Rams Clostridium novyi Type A Tetanus Clostridium tetani Pathology: Typical lesions of severe subcutaneous, peripharyngeal, perilaryngeal and peritracheal oedema (clear, straw coloured), hydrothorax, hydropericardium, pulmonary oedema and wounds on forehead. Collect affected tissues into 10% buffered formalin. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Anaerobic culture of affected organs or affected subcutaneous tissues and exudates (fresh organs or swabs with anaerobic transport medium). Other tests: Fluorescent antibody test (FAT) of impression smears for the identification of C. novyi in tissue samples. Pathology: Macro- and micropathology is non-specific. A full set of organ samples * should be collected into 10% buffered formalin to exclude other differentials. Bacteriology: Anaerobic culture of fresh tissues or culture swabs from wound sites in anaerobic transport media. Molecular Biology: PCR detection of toxin encoding genes in serum, tissue samples and cultures. Theileriosis Theileria parva East Coast Fever, Corridor Disease, January Disease Toxoplasmosis Toxoplasma gondii Tuberculosis Other Tests: A live mouse bioassay may be performed on serum and wound samples or culture supernatants. Controlled Disease Please refer to Reproduction Bovine Abortion Investigation. - Controlled Disease Mycobacterium spp. (Gram positive, aerobe) Yersinia Infections Yersinia enterocolitica, Yersinia pseudotuberculosis (Gram negative, facultative anaerobe) Pathology: Typical macroscopic and histological lesions of gastroenteritis, enterocolitis and abortion. Include samples from affected target organs in formalin although a full set of organ samples * should always be collected to exclude other differentials. Bacteriology: Faecal swabs, fresh faeces, intestinal contents and mesenteric lymph nodes in cases of diarrhoea. Please refer to Reproduction Bovine Abortion Investigation for sample collection. Gastroenteritis, enterocolitis and abortion in cattle, sheep, pigs and goats. Clinical disease has not been recorded in SA. * A full set of organs comprises: Brain and spinal cord, eye, tongue, oesophagus, trachea, lung, heart, thymus, kidney, liver, spleen, adrenal glands, ileum, jejunum, caecum, rectum, rumen, abomasum, diaphragm, skeletal muscle and mammary glands or udder. The following should be sent at the very least: brain and spinal cord, lung, heart, thymus, kidney, liver, spleen, ileum, jejunum, caecum, rectum, rumen, abomasum and skeletal muscle. 292