Pathology of the reproductive tract 2 Flashcards
Why is the gravid uterus more prone to infection than the non-gravid uterus?
- Influence of persistent progesterone stimulation
- Chorionic epithelium secretes substances that predispose the gravid uterus to infection
- Placenta and embryo and immuno-privileged sites so are not directly protected by the maternal immune system
Name three bacterial causes of abortion
- Brucella abortus (notifiable)
- Campylobacter
- Chlamydia abortus
Describe the gross effects of Brucella abortus
- Oedema of foetal membranes
- Necrotic cotyledons (soft, yellow-grey, brown exudate)
- Thickened intercotyledonary membranes with yellowish, gelatinous fluid
- Foetuses with serosanguinous fluid in subcutaneous tissue and body cavities
Describe Camplyobacteriosis in cattle
Necrotic cotyledones (= brucellosis)
Describe Camplyobacteriosis in sheep
Late term abortions
Describe chlamydiosis in sheep and goats
- Late abortions, premature lambing
- Immunity to further abortions after first
- Foetuses and cotyledones = brucellosis
- Can be stained with modified Ziehl-Neelsen
Name two protozoal causes of abortions
- Neospora caninum
- Toxoplasma gondii
Describe the effects of Neospora caninum
- Cattle
- Mid to late gestation (3-9 months)
- Aborted foetus
Describe the macro and microscopic appearance of Neospora caninum
- No macroscopic alterations
* Microscopically - focal non-suppurative (no neutrophils) encephalitis, myocarditis +/- protozoal cysts.
Describe the effects of Toxoplasma gondii
- Sheep, goats
- Late in gestation
- Aborted foetus
Describe the macro and microscopic appearance of Toxoplasma gondii
- Macroscopic - usually without any alterations
* Microscopically - focal non-suppurative encephalitis +/- necrosis in other tissues
How does Toxoplasma gondii appear grossly
Placenta: bright red cotyledones with multiple, 1-3 mm, yellow-white foci scattered among the cotyledons
(Severe acute necrotising placentitis)
Name some viral causes of abortions
- Bovine viral diarrhoea virus
- Border disease virus
- Equine herpes virus 1
How does BVDV affect pregnancy in the 1st trimester?
Abortion or mummification
How does BVDV affect pregnancy after the 1st trimester?
Congenital defects - the fetus is infected with BVDV
Describe the signs/effects on a foetus born infected with BVDV
- +/- Cerebellar hypoplasia
- Por/hydrancephaly
- Microencephaly
- Hypomyelination
- Retinal atrophy
- Optic neuritis
Describe Por/hydrancephaly
Induced by a virus in the brain that causes a focal area of necrosis, these areas become flooded with fluid and they expand.
In severe cases a large part of the neural parenchyma is replaced with fluid – can look similar to hydrocephalus
Describe how border disease virus affects pregnancy
- Ovine pestivirus – closely related to BVDV.
- Causes similar reproductive disease in sheep as BVDV in cattle i.e. abortion on infection early in gestation.
Describe the congenital defects caused by border disease virus
Hypomyelinogenesis and growth of hair instead of wool
‘Hairy shakers’ occur due to which agent?
Border disease virus
Describe the effects of Equine herpes virus 1 on pregnancy
- Important cause of pregnancy failure in mares (also causes respiratory and CNS disease in horses)
- Infection of arteriolar endothelial cells leads to the virus entering placenta then fetus
Describe foetal lesions due to Equine herpes virus 1
Severe pulmonary and systemic oedema, multifocal hepatic necrosis
Name 3 porcine reproductive viruses
- Porcine parvovirus
- Porcine Reproductive and Respiratory Syndrome (PRRS) virus
- Porcine circovirus 2
Describe how porcine parvovirus affects a foetus
Important cause of SMEDI (stillbirth, mummification, embryonic death, infertility) fetal death and mummification.
Why are foetuses affected by parvoviruses?
Parvoviruses can only complete their life cycle in rapidly dividing cells which is why it affects a developing foetus
Which virus induced abortion secondary to umbilical arteritis?
Porcine Reproductive and Respiratory Syndrome (PRRS) virus
Which virus replicates in fetal lymphoid tissues and causes death?
Porcine circovirus 2
Name 3 causative agents of vaginitis/vulvitis
Bovine herpesvirus-1
Equine herpesvirus-3
Trypanosoma equiperdum
Which conditions are caused by bovine herpes virus?
- Infectious bovine Rhinotracheitis
- Infectious pustular vulvovaginitis
- Blanoposthitis
Describe the gross and histological appearance of BHV 1 infection
- Multifocal to coalescing necrotising lesions on the mucosal aspect of the proximal vagina.
- Herpes virus = DNA virus – replicate in the nucleus of cells. Can see large intranuclear inclusion bodies
Describe necrotising vaginitis and vulvitis and name the agent
Due to secondary infection of deviated tissue (previous trauma due to difficult delivery)
Fusobacterium necrophorum
Name 3 tumours of the vagina
- Leiomyoma
- Fibroma
- Transmissible venereal tumour
Describe a vaginal leiomyoma
Most often in middle-aged bitches – benign
Single or multiple
Derived from smooth muscle cells of vaginal wall
Describe the features of a transmissible venereal disease
- Bitch / dog (jackal, coyote, fox)
- Rare – 1o areas where there is a feral dog population
- Venereal transmission
- It is the neoplastic cells themselves that are transmitted
- Rapid growth, occasionally metastatic but spontaneous regression usual within 6 months
Mastitis = ?
Inflammation of the mammary gland usually response to invasion of the gland by microbes
What are the routes of invasion into the mammary gland?
- Through teat canal (= usual route)
- Haematogenous (tuberculosis, brucellosis)
- Percutaneous (complication of local skin lesions)
How is mastitis most commonly diagnosed?
microbiological culture of milk/exudate is most more efficient than histopathology
There is a predisposition of dairy cows to mastitis for what reason?
High incidence of trauma to orifice, sphincter, streak canal of teat
Describe the structures of the treat and streak canal
• Lined by stratified squamous epithelium
• Partially occluded by coagulum (natural barrier), consisting of …
- Keratin-like material from epithelial lining
- Waxy component of milk
• Trauma may cause breakdown of barrier
Resistance to mastitis caused by … decreases with age
Streptococcus agalactiae
Resistance to mastitis caused by … does not decrease with age
Staphylococcus aureus
Describe the agents and effects of streptococcal mastitis
- Strep. agalactiae (mammary gland as natural, sole habitat)
- Entry via teat canal
- Usually permanent mastitis (organism persists)
- Organisms invade epithelium -> acute purulent inflammation, then chronic inflammation with fibrosis.
Describe the agents of Staphylococcal mastitis
- Predominantly in younger cattle
- Staph. aureus, Staph. intermedius, Staph. hyicus
Describe the gross features of Staphylococcal mastitis
Gangrenous mastitis
• Usually affecting teat + adjacent portions of udder
• Tissue becomes blue, insensitive + cold
• Sloughing / separation of affected areas after ~ one week
Name the primary agent of Coliform “toxic” mastitis in cattle
E.coli
Name some secondary agents of Coliform “toxic” mastitis in cattle
Enterobacter, Klebsiella, Citrobacter, Serratia, Proteus (part of environmental flora; infection -> level of environmental exposure; milk derived infection)
Describe the gross effects of Coliform “toxic” mastitis in cattle
- Lesions induced by endotoxins (injury to microvasculature of alveolar walls + interstitium)
- BLOODY DISCHARGE
- Macroscopic: Massive oedema, haemorrhage
- Damage to blood vessels may be so extensive that serum oozes through the surface of the udder skin, as well as into the mammary gland
Describe the histological appearance of Coliform “toxic” mastitis in cattle
- Necrosis of epithelium, oedema of septal tissue
- Extensive necrosis of tissue maybe seen after some days
- Sequestration is frequent if the animal survives
- Infiltrating inflammatory cells into mammary acini + milk ducts with tissue necrosis.
Name the agent that causes summer mastitis
Trueperella pyogenes
Summer mastitis causes sporadic acute mastitis due to?
- Penetrating injury
- Contamination by flies attracted to pre-existing teat lesions
- Infection via teat canal
Which cows are mostly affected by Summer mastitis?
Mainly affecting immature + non-lactating glands of animals in pasture (dry cows)
Describe the gross infections of summer mastitis
Necrotising suppurative galactophoritis with abscess formation
What are the causative agents of mastitis in sheep?
i) Staph. aureus – early in lactation -> chronic granulomatous mastitis.
ii) Pasteurella haemolytica – late in lactation -> necrotising mastitis.
Which spp are most affected by mammary tumours?
Most frequent tumours in bitches, third most frequent tumours in queens, rare in other species
Describe myoepithelial cells
- Continuous layer around teat sinus and ducts, discontinuous layer around acini
- Secrete mucinous ground substance
What is the prognosis of mammary tumours in dogs?
- Percentage malignant of total removed: 30-40%
- Mean survival time (malignant tumours): 4-17 months
- Tumour type is important prognostic factor
What is the prognosis of mammary tumours in cats?
- Percentage of malignant to total removed: > 80%
- Carcinomas: strong tendency of local recurrence and metastasis
What are some poor prognostic factors in cats and dogs for mammary tumours?
- Age
- Diameter of primary tumour
- Necrosis
- Incompleteness of surgical excision
- High mitotic rate
- Invasive growth
- Presence of tumour-infiltrating lymphocytes
- Metastasis
Compare simple and complex adenomas
Simple adenoma (simple = one cell type) - composed of well-differentiated luminal epithelial or myoepithelial cells (rare) Complex adenoma (complex = two cell types) - composed of well-differentiated luminal epithelial and myoepithelial cells (common)
A benign mixed mammary tumour contains which components?
Epithelial components and mesenchymal components (cartilage and/or bone and/or fat)
Name and describe the most malignant mammary tumour
Anaplastic carcinoma
- Highly infiltrative carcinoma of pleomorphic epithelial cells, not classifiable in one of the other categories
Name the 2 benign mammary tumours of a cat
Simple adenoma (rare) Complex adenoma (rare)
Name 3 malignant mammary tumours of a cat
- Non-infiltrating (in situ) carcinoma (rare)
- Tubulopapillary carcinoma
- Solid carcinoma
Name the hormonal mammary change of cats
Feline mammary hypertrophy (and hyperplasia) (= fibroadenomatous change)
Describe feline mammary hypertrophy
Hormonally induced proliferation of primarily intralobular ducts within a proliferative oedematous, fibrous stroma
- Non-encapsulated
- One or several mammary glands
- Benign, often rapid growth
Feline mammary hypertrophy is under the influence of?
Progesterone
Which cats are most affected by feline mammary hypertrophy
In progesterone-treated, pregnant and very young cats (associated with exogenous and endogenous progesterone)
How can feline mammary hypertrophy be treated?
Ovariohysterectomy, termination of pregnancy or progesterone treatment
