Bovine - Infectious Causes of Abortion

sihirlifil's version from 2017-09-27 23:45


Question Answer
Bovine Viral Diarrhea Virus (BVDV): family?Pestivirus (RNA)
(Related to Hog cholera, Border disease)
Bovine Viral Diarrhea Virus (BVDV): how are the virus types & biotypes split?Type 1 and Type 2, each with cytopathic and noncytopathic biotypes within them
Bovine Viral Diarrhea Virus (BVDV): what is the difference between cytopathic and noncytopathic biotypes?Mutation causes CP biotype to kill the cells in tissue culture, and NCP biotype to not kill cells
Bovine Viral Diarrhea Virus (BVDV): Which biotype establishes persistent infection?Noncytopathic
Bovine Viral Diarrhea Virus (BVDV): Fatal mucosal disease happens how?Persistently infected individual (i.e. NCP biotype) is exposed to a CP biotype that is immunologically identical to the NCP virus associated with the infection
Bovine Viral Diarrhea Virus (BVDV): Post-natal, immunocompetent, subclinical infection =95% of infected animals
Results in immunosuppression and may be a component of Bovine Respiratory Disease Complex
Bovine Viral Diarrhea Virus (BVDV): Post-natal, immunocompetent, peracute infection =Type 2 NCP (maybe type 1 involved)
Results in death
Bovine Viral Diarrhea Virus (BVDV): Post-natal, immunocompetent, acute infection =Cattle between 6 months – 2 years
Fever, oral erosions, diarrhea; most animals recover
Bovine Viral Diarrhea Virus (BVDV): Post-natal, BVD-tolerant animal with PI gets infected =Mucosal disease caused by superimposition of CP BVD virus
**Bovine Viral Diarrhea Virus (BVDV): Post-natal, BVD-tolerant animal with no PI gets infected =Results in persistent infection (fetal exposure followed by survival)
Virus shed as adults
** Bovine Viral Diarrhea Virus (BVDV): NCP BVD during first half of gestation =1) Persistant infection, calf survives (between 40-100 days gestation)
2) Abortion (before 170 days gestation)
3) Congential defects, calf survives (100-150 days gestation)
**Bovine Viral Diarrhea Virus (BVDV): NCP BVD later in gestation =1) Abortion less frequent after 125 days
2) Fetuses antibody positive by 180d
**Bovine Viral Diarrhea Virus (BVDV): Infection after 170 days gestation =No significant fetal disease (have antibodies after 180d!)
Bovine Viral Diarrhea Virus (BVDV): Diagnosis?Aborted fetuses
Congenital anomalies
Persistently infected animals
Bovine Viral Diarrhea Virus (BVDV): do viremic animals produce titer to homologous BVD virus?No
Bovine Viral Diarrhea Virus (BVDV): do vaccinated animals produce titer to BVD virus?No
Heterologous field strain may produce low titers
Bovine Viral Diarrhea Virus (BVDV): how is herd screening done?Pooled samples sometimes used
Biopsy by taking notch out of the ear, used for screening for PI calves
Bovine Viral Diarrhea Virus (BVDV): what is the MLV vax used for? Caution?Modified CP BVD used to prevent persistent infections
Not used in pregnant animals
Bovine Viral Diarrhea Virus (BVDV): Killed vaccine needs?2 doses for protection
Neosporum caninum: what is it?Protozoan parasite with host/intermediate host
Neosporum caninum: what role does the dog play in the life cycle?Host, oocysts excreted
Neosporum caninum: what role does the cow play in the life cycle? what happens?Intermediate host
Dog poop oocytes --> cows consume oocysts on pasture, sporozoites released --> tachyzoites proliferate, infect neighboring cells --> tissue cysts with bradyzoites form in CNS tissue
Neosporum caninum: what happens to infected animals?ALL become persistently infected
Neosporum caninum: transmitted how?Transplacental (vertical)
Neosporum caninum: what happens to the fetus when cow is infected?May abort
May survive to become persistently infected
Neosporum caninum: is a vaccine available?Yes, but still being tested for efficacy (live tachyzoites)
Caused by protozoan, so difficult to prevent dz from happening
Neosporum caninum: how to prevent horizontal transmission?Prevent fecal contamination of feed by dog poop
Clean up aborted fetuses, dead calves, placenta
Neosporum caninum: how to prevent vertical transmission?Keep only seronegative animals (often not possible); cull positives
Vaccinate (still evolving)
Neosporum caninum: more problem in beef or dairy?Dairy because of management (dairy more likely to be in situation where they ingest infected silage)
Infectious Bovine Rhinotracheitis: caused by what?Herpesvirus (BHV-1)
Infectious Bovine Rhinotracheitis: how often is it diagnosed?One of the most frequent viral causes of abortion in cattle
Infectious Bovine Rhinotracheitis: how long does infection last?Lifelong latent infection (its herpes!)
Infectious Bovine Rhinotracheitis: what does it cause?Abortion storms in susceptible herds
Infertility (early embryonic death)
Localized genital infections (endometritis, oophoritis, pustular vulvovaginitis, balanoposthitis)
Infectious Bovine Rhinotracheitis aka?“Death ray” for conceptus in unvaccinated female
Infectious Bovine Rhinotracheitis: contagious?YES and virulent!
Infectious Bovine Rhinotracheitis: in unvaccinated cows, infection results in?Virus crossing placenta rapidly and establishing fetal viremia
Peracute necrosis of fetal organs causes EED (24-48 hours)
Infectious Bovine Rhinotracheitis: gross changes of aborted fetus?Red-tinged serous fluid in body cavities and reddened fetal tissues (fetal death happens too rapidly for much change)
Infectious Bovine Rhinotracheitis: CS in cows?Usually respiratory or conjunctivitis
Infectious Bovine Rhinotracheitis: are injectable MLV vax used?NOT IN PREGNANT!
New vaccines being developed for use in pregnant cows if previously vaccinated
**Infectious Bovine Rhinotracheitis: types of vaccines available?Injectable MLV (prebreeding heifers)
Intranasal MLV (virus only replicates where temp is below normal body temperature)
Brucella abortus: aka?Bangs Disease (“undulant fever” in homo sapiens)
Brucella abortus: Where does it primarily exist?Bison and elk herds (only 1-2 cattle herds/year in USA)
Endemic in much of the world
Brucella abortus: vaccine available?Very effective and can differentiate between vaccine & infective strain
Brucella abortus: can people get it?YES ZOONOTIC
Leptospira interrogans: serovar hardjo causes what?Infertility, abortion of fetuses 4 months-term, weak calves at birth
Leptospira interrogans: serovar pomona causes what?Abortion last trimester
Leptospira interrogans: 5-way vax includes which serovars?Hardjo, pomona, canicola, grippotyphosa, icterohaemorrhagiae
Leptospira interrogans: signs of acute infection?Fever, hemolytic anemia, hemoglobinuria, icterus; agalactia and mastitis in lactating cattle
**Leptospira borgpetersenii: how prevalent?Most prevalent bovine lepto in USA
**Leptospira borgpetersenii: how did it evolve?There is no environmental transmission! Animal-animal only.
**Leptospira borgpetersenii: is there a vax? Problems?Monovalent bacterin 2 doses @ 4 week interval
Immunity short-lived
(Animals must be neg for Lepto before vax)
Leptospira borgpetersenii: transmission?Shed in urine for several weeks, survive in wet environment for a month
Leptospira borgpetersenii: how do organisms get in?Penetrate intact mucus membranes or abraded skin
Leptospira borgpetersenii: how is it diagnosed?Difficult- most animal’s don’t show CS
Listeria monocytogenes: infections caused by?Ingesting/inhaling organism when massive numbers grown in spoiled silage
Listeria monocytogenes: CS?Encephalitis, abortion
Even if a whole herd is affected, only a few may show CS
Listeria monocytogenes: how do humans become infected?Handling aborted material
Coxiella Burnetti: what is it? aka?Bacteria, rickettsial parasite. Q-fever
Coxiella Burnetti: CS?Abortion rare in cattle
Toxoplasma gondii: what is it?Protozoan
Toxoplasma gondii: CS?Abortions rare in cattle
Tritrichomonas foetus: what is it?Flagellated protozoan
Tritrichomonas foetus: transmitted how?From infected bull, grows in vagina & uterus
Tritrichomonas foetus: indications of infection in herd?First indication- cows coming back into heat during breeding season
Pregnancy rates lower than normal
Conceive later in season & calve late
Tritrichomonas foetus: CS in cows?Inflammation of uterus
EED (most common)
Occasionally pyometra, abortion (least common, usually first half gestation), macerated fetus
Tritrichomonas foetus: tx for cows?Usually clear infection after a few estrus cycles
**Tritrichomonas foetus: CS in bull?Asymptomatic! Transient colonization (stored!) in young bulls, survives in inner lamina of prepuce of old bulls
Tritrichomonas foetus: diagnosis?State testing programs in ID, some other western states
Culture of preputial cavity of bull (scrape & flush inner lamina of prepuce, culture in special media)
Tritrichomonas foetus: problem with culturing?Other protozoa may give false positives; positives may require additional ID for T, foetus; need multiple cultures (sensitivity 80%)
Tritrichomonas foetus: tx for bulls?Young self-cure
Old: Ipronidazole, dimetridazole, metronidazole (all illegal lol), slaughter positive bulls
Tritrichomonas foetus: how to prevent?Use only negative bulls and cows in breeding herd (test all bulls)
Tritrichomonas foetus: vax?Trichguard = commercial vaccine
Does not prevent infection but hastens recovery/self-cure (questionable efficacy in bulls)
Campylobacter fetus: what is it?Gram-negaive motile bacteria (like Vibrio)
Campylobacter fetus: spread how?Infected bulls when mating
Campylobacter fetus: CS in cow?Same as T. foetus, but pyometra less common
Occasional abortion 4-7m
Campylobacter fetus: do cows develop immunity?Yes, after initial endometritis/embryonic loss
Campylobacter fetus: CS in bull?NONE but may remain infected persistently
Campylobacter fetus: diagnosis?Pattern of infertility
Sample & culture bull separately from T. foetus
Culture cow (cervical mucus, ID specific IgA) (also can test bull by breeding to virgin heifer, then sample cervical mucus for 18-30 days)
**Campylobacter fetus: vax?Bactirin effective in both cows and bulls as cure
Epizootic Foothill Abortion: caused by? vector?Pajaroellobacter abortibovis (deltaproteobacteria)
Ornithodorus coriaceus tick
Epizootic Foothill Abortion: found where?California, Nevada (one of main abortion diagnoses here)
**Epizootic Foothill Abortion: affects cows how?Pregnant/new cows highly susceptible, doesn’t affect subsequent pregnancies
Bluetongue virus: transmitted by?Culicoides biting midges, vertical & horizontal
Bluetongue virus: abortion caused by?Attenuated vaccine viruses
Bluetongue virus: dx?PCR
Bluetongue virus: vax?Need to be tailored to specific strain for the area (2 dozen types of bluetongue virus)
Mycotic abortion: abortion usually occurs when?Late pregnancy
Mycotic abortion: most commonly isolated?Aspergillus fumigatus in USA (Mortierella wolfii in NZ)
**Mycotic abortion: clinical indication?”Leathery placenta”
**Mycotic abortion: diagnosis?Severe placentitis with necrosis of the cotyledons and leathery thickening of intercotyledornary space
Fetus has skin lesions in 25% of cases
Submit placenta for direct micro exam, histopath, fungal culture
*Persistant infections (2)Bovine Viral Diarrhea Virus
Neospora caninum
*Zoonotic infections (5)Bruceclla abortus
Listeria monocytogenes
Coxiella burnetti
Toxoplamsa gondii
*Venereal diseases (2)Tritrichomonas foetus
Campylobacter jejuni
*Regional insect-transmitted (4)Epizootic Bovine Abortion
Akabane vius
Schmallenberg virus
*Opportunistic agents (12)Aspergillus
E. coli
Trueperella pyogenes
Chlamydia abortus (may be zoonotic!)
Histophilus somni

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