[1] Identification of C. fetus species in infected animals or people is routinely performed by culture on blood or cefoperazone deoxycholate agar.

[4] Disease in humans occurs through zoonotic transmission of C. fetus mainly via ingestion of contaminated food or water sources.

[13] Identification of C. fetus requires aseptic sample collection, followed by culture and potentially further biochemical and molecular methods.

[14] Modified charcoal cefoperazone deoxycholate (CCD) agar is a growth medium designed to isolate Campylobacters from feces.

[15] To increase reliability of identification, molecular methods such as polymerase chain reaction or DNA sequencing may be utilized.

[14] Other methods of identification include histology, immunohistochemistry, direct immunofluorescence, agglutination and enzyme-linked immunosorbent assay.

in general possess membrane lipopolysaccharide (LPS) with low biological activity compared to other bacteria (i.e. Enterobacteriaceae), subsequently avoiding detection by the host immune system and which may explain why persistent infections can occur.

[18] Additionally, Cfv has long LPS side chains (O-antigens) that may resist complement-mediated bacterial killing.

Infections with Cff appear to be more detrimental in ewes than in cows, spreading readily through a flock resulting in abortion storms.

[21] Bovine infectious infertility is a reproductive disease caused by infection of Cfv that leads to early embryonic mortality in cattle.

[20][4][23][14][5] Alongside Tritrichomonas foetus, bovine venereal campylobacteriosis considered an important sexually transmitted disease (STD) of cattle.

[5][24][17][28] Transmissibility from carriers to naïve cows is high,[23] such that outbreaks of Cfv in the herd can often be traced to the introduction of a new bull.

[29] Rather than the bacterial colonization itself, the ensuing inflammatory response in the uterus and oviducts is often the cause of early embryonic mortality.

[27] Retention of the deceased fetus causes necrosis of the placenta and placental lesions are not easily distinguished from Brucella abortus, characterized by cotyledon colour change from pink/red to yellow/brown.

[17] Specifically, in sheep and goats, fetuses aborted due to campylobacteriosis, are often accompanied with an edematous placenta, friable cotyledons and upon necropsy exhibit necrotic foci on their livers.

[17] Infected ewes rarely show systemic disease, but may include diarrhea, fever, and vaginal discharge.

[4] In rare cases, a fetus may die in utero and cause an ascending infection from the placenta, septicemia and possibly death in the ewe.

[4] Ewes can often mount sufficient immune responses following infection,[4] therefore subsequent lambing seasons are not as severely affected.

[14] Symptoms of acute gastroenteritis associated with Cff infections include abdominal cramping, nausea, diarrhea and fever.

[14] Occasionally, abortion in humans can occur, similar to that in sheep, as a result of placental infection through septic spread of Cff from the gastrointestinal tract.

[4][18] The fetus can either undergo spontaneous abortion or be born with an ongoing infection which can eventuate in the infiltration of nervous tissues.

Often, C. fetus may not be suspected until herd level changes are noticed, generally at the end of the breeding season (Cfv) or end of herd gestation (Cff) (e.g., high incidence of open cows, multiple returns to service, high incidence of abortions in ewes).

[34] C. fetus is extremely delicate to environmental conditions including sunlight, dehydration, increased temperature, and high O2.

In addition, C. fetus can be quickly outgrown by competing microbes, indicating that timely culture and sample submission are important.

For reproductive diseases, samples may include vaginal mucus swabs, preputial washes or scrapings with buffered sterile saline, stomach contents or tissue of abortuses.

Samples from stomach contents and vaginal discharges allow accurate diagnosis of C. fetus and its subspecies for epidemiological and pathogenic purposes.

The PCR assay differentiates between subspecies of C. fetus, which important to determine pathogenesis and develop an effective treatment plan.

However, diagnosis of C. fetus may be problematic due to poor growth in atmospheric conditions and the ability to be outcompeted by contaminating microbes.

[31] Infected bulls are typically removed from the herd or culled as treatment can be difficult and may result in persistent carriers.

C. fetus may evade complete detection and eradication by the immune system as chronic and relapse cases have been noted.