Term
| Why is mammary disease important? |
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Definition
-commercially valuble (dz. results in dec. milk production and cost for milk produced, plus mastitis is expensive to treat)
-milk provides passive immunity to neopnate
-milk provides nutrients for neonate
-hyperplastic and neoplastic dz are common
-some pathogens transmitted in milk e.g. TB |
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Term
| Briefly describe normal structure of mammary gland? |
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Definition
-multiple lobules of modified apocrine sweat gland
-each lobule lined by layer of secretory epi. cells surrounded by contractile myoepithelial cells
-milk ducts converge at gl. cistern which fills teat cistern -exits via teat canal to external teat cistern |
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Term
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Definition
| -lined by stratified sq. keratinising epi. |
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Term
| Describe the physical factors involved in the defence of the mammary gland |
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Definition
-TEAT CANAL most important - lenth and diameter important
-sphincter muscle and keratin plug at teat orifice
-flushing action of milk |
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Term
| Describe the soluble factors involved in the defence of the mammary gland |
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Definition
-lactoferrin (major iron binding protein, so iron withheld from bact.)
-lysozyme (lysis of cell wall proteoglycan)
-complement (bact. destruction via MAC and opsonisation)
-cytokines |
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Term
| Describe the humoral/cellular factors involved in the defence of the mammary gland |
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Definition
-immunoglobulins (IgG transferred from plasma, IgM and IgA synthesised locally)
-macrophages (resident, detector cells)
-neutrophils (effector cells) |
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Term
| Describe the immunoglobulin component of milk |
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Definition
-normal milk has low IgG conc
-in dz. get a great incr. in transfer of IgG from plasma
-IgM and IgA synthesized locally in dz |
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Term
| What is the role of IgM and IgA in milk? |
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Definition
-IgM and IgA act as opsonins
-IgA prevents bact. forming adhesions |
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Term
| How do macrophages recruit neutrophils? |
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Definition
| If bact invade, macrophages produce leukotriene-B - a potent chemoattractant for neutrophils |
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Term
| Name poss. congenital conditions of the mammary tissue |
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Definition
1. malformations, usually teats e.g. aplasia, hypoplasia, inversion, fistulae, non-patentcy
2. Supernummary teats (usually cattle)
3. Pigmentation (melanosis, usually pigs) |
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Term
| How does infection enter the mammary gland? |
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Definition
almost always via the teat canal i.e. ascending
-poss. by haematogoneous or percutaneous inf. |
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Term
| Describe the 4 stages of mastitis / infection of the udder |
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Definition
1. PENETRATION - inf. reaches the udder, usually via the teat canal
2.INFECTION - bact. multiply in milk sinus and ducts
3.INVASION - glandular tissue invaded by bact, producing inflam response
4.HEALING - may be complete resolution in mild cases or fibrosis and atrophy in severe cases |
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Term
| When/where do pathological changes take place in mastitis? |
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Definition
-coliforms produce effects in duct system by release of LPS/endotoxin
-most bact. invade glandular tissue and create inflam there |
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Term
| What are the pathological changes in mastitis? |
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Definition
-inflam
-stratified squamous metaplasia of duct epithelium (and so loss of secretory function and milk production)
-atrophy of affected gl. acini that persists for rest of lactation
-fibrosis - can cause permanent loss of function, esp. if ducts blocked |
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Term
| How is bovine mastitis classified? Give examples |
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Definition
-Contagious / Primary udder pathogens
e.g. Streps and Staphs (Strep. agalactiae/dysgalactiae, Staph. aureus)
-Environmental
e.g. coliforms
(Pseudomonas, Strep. uberis, E. coli, Klebsiella, Enterbacter aerogens) |
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Term
| Describe strep. mastitis of cattle |
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Definition
-infection tends to be low grade and permanent w. occasional flare-ups
-organisms only invade short distance into mammary tissue
-acute inflam, oedema and exudation (PUS) followed by fibrosis and involution |
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Term
| Describe staph. mastitis of cattle |
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Definition
-organisms invade deep into glandular tissue
-toxins cause tissue damage and vasc. thrombosis
- vasculitits results in hypoxia and GANGRENOUS NECROSIS |
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Term
| Describe environmental / coliform mastitis of cattle |
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Definition
| -Acute, necrotising and haemorrhagic mastitis -tends to be housed cattle in winter-spring -endotoxin production in gland cistern damages microvasculature of glandular and interstitial tissues - results in necrosis/sloughing of duct epi., subcut oedema, haemorr -may cause severe, systemic dz. including septicaemia, +/- death (esp. E.coli) |
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Term
| Describe summer mastitis of cattle |
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Definition
-due to Arcanobacterium pyogenes
-non-lactating cattle, incl. heifers and males
-a necrotising suppurative galactophoritis, w. abscesses and fistula
-may develop fibrosis +/- stenosis
-may following penetrating injury / contamination of lesion by flies |
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Term
| What factors influence mastitis in dairy cattle? |
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Definition
| Pathogen, mgmt, cow factors |
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Term
| What pathogen factors influence mastitis in dairy cattle? |
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Definition
-persistence/resistence
-toxin production |
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Term
| What mgmt factors influence mastitis in dairy cattle? |
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Definition
| -faulty milking machinery -poor dairy hygiene -inadequate teat dipping -contaminated bedding -inapropriate dry cow therapy |
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Term
| What cow factors influence mastitis in dairy cattle? |
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Definition
-udder and teat conformation
-teat infection and injury
-poor immune or inflam resp. |
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Term
| Name viruses which can infect cattle teats. Which are zoonotic? |
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Definition
-Pseudocowpox (zoonotic) - parapoxvirus
-Cowpox virus (zoonotic)
-Bovine papillomavirus
-Bovine mammillitis - Bovine herpesvirus-2 |
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Term
| Which virus of cow teats causes "milker's nodule"? |
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Definition
| Pseudocowpox / Parapoxvirus |
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Term
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Definition
| -caused by parapoxvirus -common and endemic in cattle -erythematous macules and papules -in people causes "milker's nodules" i.e. zoonotic |
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Term
| Describe bovine papillomavirus |
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Definition
| -warts on teats -predominately in cows w. suckling calves (inf. pred. in young, which then transfer to teats when suckling) |
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Term
| Describe bovine mammillitis |
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Definition
-caused by bovine herpesvirus-2
-mainly in lactating cows
-swollen, painful teat w. bullae which rupture leaving ulcers/ erosions |
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Term
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Definition
| -severe - often peracute toxaemia w. sudden death -acute necrotising gangrenous mastitis ("blue bag") |
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Term
| What bact are associated w. ovine mastitis? |
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Definition
Most commonly: Staph aureus
Mannheimia haemolytica |
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Term
| What bact. are associated w. caprine mastitis? |
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Definition
Mycoplasma agalactiae
Mycoplasma mycoides mycoides |
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Term
| What are MMV and CAE and what are they associated with? |
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Definition
| MMV = Maedi-visna virus of sheep CAE = Caprine arthritis encephalitis (closely related lentiviruses) Important causes of chronic lymphoproliferative mastitis (as part of a systemic dz) - "hard bag" or "hard udder" |
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Term
| What clinical syndrome is recognised in porcine mastitis? |
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Definition
| mastitis-metretis-agalactia |
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Term
| Describe porcine mastitis |
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Definition
-peracute clin. syndrome occuring shortly after parturition
-main feature is hypo/agalactia
-moderate mastitis, mild metritis, constipation, cystitis, anorexia, pyrexia |
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Term
| What is the aetiology of porcine mastitis? |
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Definition
| Endotoxaemia, esp E.coli, thought to be involved |
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Term
| Roughly what is the incidence of mammary tumours in dogs and cats? |
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Definition
Very common in dogs, much less so in cats.
~50% malignant in dogs, ~90% malignant in cats |
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Term
| What breed of cat is "over-representated" in the incidence of mammary tumours? |
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Definition
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Term
| Briefly describe mammary tumours of the bitch |
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Definition
-incidence of benign and malignant roughly equal -majority of epithlial origin
-histiological patterns = simple, complex, mixed -metatstases is common, esp lungs or bone |
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Term
| Describe the different histiological patterns of mammary tumours |
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Definition
Simple - only neoplastic, luminal epithelial cellls
Complex - neoplastic, luminal epithelial cellls, plus neoplastic myoepithelial cells
Mixed - neoplastic luminal epithelial and myoepithelial cells, plus non-neoplastic, metaplastic c.t., cartilage +/or bone |
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Term
| What are the risk factors for mammary neoplasia in the bitch? |
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Definition
AGE - peak incidence at 10years, rare below 5 years
BREED - not relevant
SITE - 70% of tumours in 4th/5th glands
-40% of animals have mutliple gl. involvement when presented |
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Term
| Describe the aetiology of mammary tumours in dogs |
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Definition
-hormones involved - R for oestrogen, progesterone and prolactin and GFs associated (some tumours in males associated w. oestogen-secreting Sertoli cell tumours)
-ovariectomy significantly reduces incidence of mammary tumours (not if after 2-3yrs)
-progestagens (exogenous) incr. incidence of mammary hyperplasia and benign tumours |
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Term
| Name non-neoplastic causes of mammary gland enlargement |
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Definition
-cystic hyperplasia
-duct ectasia
-feline mammary fibroadenomatous hyperplasia
-mastitis
-fat necrosis
-gynecomastia
-pregnancy/pseudopregnancy
-hernias
-subcutaneous skin tumours / abscesses |
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Term
| What is cystic hyperplasia? |
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Definition
| milk ducts become cystic and dilate and accumulate secretions |
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Term
| What is feline mammary fibroadenomatous hyperplasia? |
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Definition
-uncommon non-neoplastic dz. of adolescent cats
-firm severe swellings of mammary glands, which may result in ulceration of overlying skin
-histiologically: proliferatinf ducts separated by abundant oedematous, proliferating c.t. |
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Term
| What is the aetiology of feline mammary fibroadenomatous hyperplasia? |
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Definition
| -associated w. progesterone (1st oestrus / elevated prog-R, exogenous progestagen tx in older cats) |
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Term
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Definition
inappropriate development of mammary gland esp. in the male
e.g. oestrogen-producing Sertoli cell tumours |
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