Campylobacter PURS - lecture notes PDF

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Campylobacter: Pathology of the Urinary and Reproductive Systems  Significance in sheep: - Campylobacter is the third most common cause of infectious ovine abortion in the UK and has increased in relative importance in recent years - Outbreaks of Campylobacter abortion tend to be sporadic in nature, although abortion rates in outbreaks of 20% or more are possible - Campylobacter can reach the uterus and necrotic placentitis causes late abortion, still birth - Lambing percentage is still a major factor in determining profit and even a small improvement will significantly increase your income. In a lowland flock for example, an increase of just 5% can increase net profits by up to 70%!

- C. fetus subsp. venerealis is associated with Bovine Genital Campylobacteriosis (BGC) or Bovine Venereal Campylobacteriosis (BVC), causing fertility problems with considerable economic losses, particularly in endemic regions

- Bovine infections with C. fetus subsp. fetus are more commonly associated with abortion and have a more sporadic occurrence

 Significance in cattle: - Campylobacter fetus subsp. venerealis causes venereal disease that usually results in infertility or early embryonic death

 Zoonotic: - Many Campylobacter species are zoonotic and these include some of those associated with reproductive disease in cattle and sheep

 What is Campylobacter? - Curved, S-shaped or spiral rods 0.5-5 μm long - Gram – - Oxidase + - Single polar flagellum, darting corkscrew motility - Microaerophilic: 5% Oxygen (37/42C)

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 Important species of Campylobacter:

 Fastidious microaerophilic bacterium: - Sheep blood agar

- Charcoalcefoperazonedeoxycholate media

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 Campylobacter virulence: - Motility important – flagella - (chemotactic to mucin/fucose) - Fimbriae? - LOS - Produces a cytolethal distending toxin (CLDT) - Adhesion - Invasion - Diarrhoea due to inflammation?

 Campylobacter as a cause of reproductive disease in sheep and cattle: - Campylobacter fetus subsp. fetus (occasionally C. jejuni)- Sheep - Campylobacter fetus subsp. venerealis (occasionally subsp. fetus) – Cattle

 Campylobacter associated with infertility in cattle: - Bovine genital campylobacteriosis (BGC) is a venereal disease also known as bovine venereal campylobacteriosis (BVC) - Aetiological agent = Campylobacter fetus subsp. Venerealis

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 How is it spread? - C. fetus subsp. Venerealis is transmitted venereally and also by contaminated instruments, bedding, or by artificial insemination (AI) using contaminated semen

 How is it spread? Bulls: - Individual bulls vary in their susceptibility to infection; some become permanent carriers, while others appear to be resistant to infection - The primary factor associated with this variability seems to be the agerelated depth of the preputial and penile epithelial crypts - In young bulls (3-4 YO), the deeper crypts may provide the proper microaerophilic environment required for chronic infections to establish

 How it spreads? Cows: - In cows, the duration of the carrier state is also variable; some clear the infection rapidly, whereas others can carry C. fetus for ≥2 yr - IgA antibodies are shed in cervical mucus in significant amounts in ~50% of cows for several months after infection and are useful diagnostically - Although most of the genital tract may be free of infection when a cow eventually conceives, the vagina may remain chronically infected throughout pregnancy

 Pathogenesis, cattle: - Campylobacter survives in the crypts of the bulls penis - Campylobacter enters the reproductive tract through coitus (sex)

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- Flagella are important for motility through mucus - Infection of the female reproductive tract results in metritis - Metritis results in poor pregnancy rates, reabsorption of foetus or death of embryo - Occasionally severe metritis results in abortion

 Clinical signs, cattle: - Systemically normal, but there is a variable degree of mucopurulent endometritis that results in the following:  early embryonic death  prolonged luteal phases  irregular oestrous cycles  repeat breeding and as a result, protracted calving periods - Observed abortions are not common (gest. period 283 d, 9.4 mo) - Bulls are asymptomatic and produce normal semen

 Post-mortem examination findings: - The foetus can be fresh with partially expanded lungs or severely autolysed - Mild fibrinous pleuritis and peritonitis may be noted, as well as bronchopneumonia - Placentitis is mild with haemorrhagic cotyledons and an oedematous intercotyledonary area

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 Placentitis:

 Fibrinous peritonitis:

 Bovine cervix, Campylobacter cervitis:

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 Samples for diagnosis, cattle: - Bovine infertility:  anoestrous mucus from cows  preputial washing from bull - Bovine abortion:  foetal abomasal contents  placenta  Campylobacter are harboured in the epithelial crypts of the penis:

 Diagnosis, cattle: - Systemic antibody responses are not helpful, because they are often due to non-pathogenic Campylobacter Spp. - A vaginal mucus agglutination test (VMAT) is useful, but because of variability in individual responses, at least 10% of the herd or at least 10 cows must be sampled - An ELISA is available for testing vaginal mucus - Bacterial culture from the vagina immediately after abortion or infection can be used for diagnosis, but the number of organisms may be low

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- Sheath washing examined using a fluorescent antibody test and or culture. For maximum accuracy, bulls should be sampled twice, ~1 wk apart - Culture from aborted foetus or placenta - PCR

 Control, cattle: - Surveillance - Use reputable AI - Investigate abortions thoroughly - Antibiotic treatment of affected cows and bulls - Vaccination (autogenous)

 Campylobacter associated ovine abortion: (gest. period: 147 d, circ. 5 mo) - Campylobacter fetus subsp. fetus (C. jejuni can also occasionally cause abortion) - Campylobacteriosis is a major (3rd commonest) cause of abortion in British sheep flocks - Abortions usually occur during the last 6 weeks of gestation - Other common causes of ovine abortion:  Chlamydophila  Toxoplasmosis  Pathogenesis, sheep: - Campylobacter survives in the environment and can be shed in the faeces and reproductive tissues - Ewes become infected through exposure to the organism in the environment – faecal oral route

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- Infection results in a bacteraemia or septicaemia which leads to damage of the placenta and thus death of the embryo/lamb

 How it is spread, sheep: - Faecal oral route - Infected pasture - Ewes exposed to infected afterbirths

 Epidemiology and incidence, sheep: - Self-limiting, as immunity develops in the flock through contact with carriers - Outbreaks are usually confined to one lambing season - Seasonality in Campylobacter recovery from sheep in GB has been reported, with a peak in winter/spring - Campylobacter shedding has been reported to be lowest (0%) in Nov. and Dec. when sheep are fed on hay and silage compared with when they are grazing pasture - The highest rates of shedding (100%) coincide with increased stress as a result of lambing, weaning and movement onto new pasture

 Post-mortem examination findings: - Hepatitis - Pericarditis - Pneumonia

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 Vibrionic ovine abortion:

 Campylobacter associated hepatitis:

 Hepatitis and fibrinous pericarditis:

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 Pneumonia, Campylobacter in an ovine foetus:

 Samples for diagnosis, sheep: - Ovine abortion:  foetal abomasal contents  placenta - Diagnosis methodologies as for bovine Campylobacter

 Management, sheep: - Keep aborted ewes, but mix with non pregnant replacements to allow ewes to develop immunity - When faced with an outbreak, the only option is to use antibiotics (generally have no impact) - Hygiene and husbandry are very important in reducing the spread of the disease

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- The correct handling of abortion material and affected sheep is particularly important since infection is easily spread within a flock - Ewes which become infected with the organism develop a lifelong immunity

 Control and prevention, sheep: - Aborted tissues, foetal membranes and discharges are all infectious and should be collected and removed to prevent the spread of infection within the flock - It is important to protect the water supply from contamination. Once infection spreads through the flock, little can be done to reduce losses - Effective killed vaccines consisting of single or multiple strains of C. fetus and a vaccine containing C. fetus as well as C. jejuni are available in some countries

 On farm risk factors, cattle and sheep: - Biosecurity - Rodents - Previous infections on farms - Open herds

 General control strategies for Campylobacter in livestock: - Vaccination? - Biosecurity - Surveillance - Closed herds/flocks

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 Summary:

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