Bovine Pathogens Flashcards
Abomasal perforation
results in acute septic peritonitis. Prognosis is grave. Clinical signs: dehydration, weakness, and expiratory grunt. Acute abomasal perforation through a single 1-2 cm ulcer occurs sporadically in young (2-4 month old) beef calves and the cause is unknown.
Abomasal torsion biochem
hypochloremia, metabolic alkalosis, hypokalemia. As a result of the torsion, animals sequester HCl int he abomasum, get hypochloremia and metabolic alkalosis. Additionally, animals become dehydrates and try to maintain adequate blood pressure by conserving sodium through renal mechanisms. Because there is alkalosis, potassium is sequestered even more than usual in cells leading to hypokalemia. Normally kidney excretes some potassium but when insufficient potassium is available, in order to reabsorb sodium to maintain blood pressure, hydrogen ions are excreted rather than potassium which results in acid urine at h same time as metabolic alkalosis, a condition know as paradoxic aciduria.
Achromotrichia
copper deficiency
Actinobaccilus lignieresii
“wooden tongue” - IV sodium iodine+anitbiotics and change feed
Actinomyces bovis
“lumpy jaw”, condition results from the entry of the normal rumen inhabitants into the body mandile (usual site) or maxilla through a break int he mucous membranes or teeth. It may be arrested with therapy using sodium iodine, antimicrobials or even isoniazid off-label, but the bony swelling seldom changes much, even if arrested.
Akabane virus
insect-transmitted virus that causes congenital abnormalities of the CNS in ruminants. Affects fetuses of cattle, sheep, and goats. AsymptomatiPeak inceidence of disease seen if cattle are infected at 3 to 4 months of gestationc infection has been demonstrated serologically in horses, buffalo, and deer in endemic areas.
Bunyaviridae; transmitted by culicoides spp
common in tropical and subtropical areas.
Calves infected late in pregnancy may be born alive but unable to stand and may have flaccid paralysis of the limbs, disseminated encephalomyelitis on PM
Anaplasmosis
Anaplasma marginale. Clinical signs: pale, icteric, and febrile. Key features: adults sick, resistant to clinical Anaplasmosis as calves. Never seen hemoglobinuria with Anaplasmosis because if is all extravascular hemolysis.
Tick-borne, treat with tetracyclines
Animal African Trypanosomiasis
African animal trypanosomiasis (AAT) is a parasitic disease that causes serious economic losses in livestock from anemia, loss of condition and emaciation. Many untreated cases are fatal
protozoan parasites in the family Trypanosomatidae. Most trypanosomes are transmitted by tsetse flies
Anopheles
mosquito responsible for transmission of Maralia
Arcanobacterium pyogenes
Most common postpartum pathogen leading to endometritis
Can also cause footrot
Bacillary hemoglobinuria (Clostridium novy type D)
hemoglobinuria, caused by germination of C. novyi type D spores in the liver after anaerobic damage by migrating liver fluke larvae. Can be prevented with vaccination.
Bluetongue
Reovirus: Small midges or gnats are the main route of transmission of bluetongue virus, although it can also be transmitted sexually or transplacentally. C sonorensis is the main species responsible for transmission int eh USA.
Bovine High-Mountain Disease (BHMD)
“Brisket disease” High-altitude pulmonary hypertension
Bovine Leukocyte Adhesion Deficiency
an adhesion molecule defect that causes granulocyte and lymphocyte dysfunction and recurrent soft-tissue infections
Bovine Leukosis Virus (BLV)
clinical lymphoma, ELISA for antibody to envelope glycoprotein gp51
Bovine Respiratory Syncytial Virus
A virus classified as a pneumovirus in the Paramyxovirus family
characteristic “honking” cough
Diagnose for PCR
Treatment: antimicrobial therapy for secondary bacterial infection
Bovine Viral Diarrhea (BVD)
flavivirus
most common in young cattle
most commonly diagnosed virus in bovine abortion cases
The pathology of BVD in the developing fetus is complex. Infection before insemination or during the first 40 days of pregnancy results in infertility or embryonic death. Infection between 40 and 125 days of pregnancy results in birth of persistently infected calves if the fetus survives. Fetal infection during the period of organogenesis (100–150 days) may result in congenital malformations of the CNS (cerebellar hypoplasia, hydrancephaly, hydrocephalus, microencephaly, and spinal cord hypoplasia). Congenital ocular defects have also been seen (cataracts, optic neuritis, retinal degeneration, microphthalmia). After 125 days of gestation, BVD may cause abortion, or the fetal immune response may clear the virus
Brucellosis
abortion (rare), retained placenta, metritis, and lack of signs in younger animals. Abortion usually occurs in last half of pregnancy and the fetuses appear relatively normal but typically there are signs of severe inflammation, including placentitis.
Vaccinated animals have tattoos and ear tags in their right ear. The first letter fo the tattoo indicates the type of vaccine. The USDA “V shield” indicated vaccination. The number indicated the last number of the year of vaccination. The information of the ear tag indicated the state by the first two numbers and then the remaining characters are a specific identifier for the animal so that it can be traced if necessary.
BST or rBST
given by injection to lactating dairy cows every two weeks to increase the amount of milk produced and to prolong lactation.
BVD fetus aborted
anytime during gestation
BVD fetus persistently infected
before 125 days of gestation
BVD fetus with congenital deformities
infected between 90-150 days of gestation, half of these will die within first year of life. Most common congenital anomaly is cerebellar hypoplasia
Campylobacter fetus ssp. venerealis
Main cause of bovine campylobacteriosis but is not shed in milk. The organism is an obligate parasite of the bovine genital tract and causes abortion. Infection usually results in temporary infertility or early embryonic death.
Campylobacter jejuni
Emerging milk zoonotic pathogen
Clostridium botulinum
produces a toxin that blocks acetylcholine release by binding the presynaptic membrane, this causes progressive motor paralysis and generalized progressive weakness. Death usually occurs due to respiratory paralysis. The bacteria often proliferate in decomposing animal or plant tissue.
Coccidiosis
Eimeria (12 species identified in cattle, 3 that cause clinical disease); summer and winter varieties. Diagnosed using McMaster’s technique. Treat with monensin.
Nervous coccidiosis - heat stable
Cochliomyia hominivorax
also know as screwworm. Large metallic blue-green colored fly. Females lay hundreds of eggs at the edge of fresh wounds on the cow; larvae hatch approximately 24 hours. As the larvae eat the living tissue, they create a huge wound. Screwworm larvae then fall off and pupate, completing their life cycle in approximately 21 days. This fly is reportable!!!
Congenital microphthalmia
Result of Bovine Viral Diarrhea infection
Contagious mastitis
Post-milk teat dip to prevent mastitis. Types: Strep agalactiae,
Corynebacterium pseudotuberculosis
se cutaneous excoriated granulomas. Large, ulcerative skin lesions resembling infected granulation tissue and lymphangitis may occur in 2%–5% of cows. Location on the animal is variable but is often associated with skin trauma. Healing often occurs without treatment or with limited topical treatment in 2–4 wk. Abortion and mastitis may also occur.
Culicoides
parasitic hematophagous midge which causes skin disease as well as transmitting disease
Dexamethasone for inducing parturition
parturition will occur within 24 hours
Dictyocaulus viviparus
bovine lungworm and cause of verminous bronchitis. Often affects younger cattle more severely. Signs include cough and frequently tachypnea. The diagnosis is frequently suggested by the seasonal incidence although confirmation with fecal examination (Baermann) is important to achieve a definitive diagnosis. Treatment with an anthelmintic of clinically affected animals is usually effective.
Direct lifecycle, no intermediate hosts.
Dietary cation-anion difference
Diet is enhanced with more anionic salts containing the strong ions chloride and sulfur and has decreased amounts of strong cations such as sodium and potassium. Used to help prevent milk fever. Cows become more acidotic which enhances parathyroid hormone function along with a better ability to utilize calcium.
Endocarditis
most commonly in the tricuspid valve, in contrast of horses and SA where the aortic valve is most commonly affected. Animal may be septic as well and have swollen joints. Common cause of endocarditis in cattle are foot abscesses and other sites where pus and blood mix.
Endometritis treament
Intrauterine penicillin (after 30 days) or tetracycline or ceftiofur can be beneficial. Some prefer dilute povidone iodine or uterine lavage with saline to avoid negative impact of antibiotic residues in the milk. Prostaglandins can also be used to “short cycle” the cow which will aid in treating the endometritis.
Enzootic pneumonias
Multifactorial but is mainly a result of poor housing and environment (poor sanitation and ventilation). Calves will have cranioventral consolidation and many times they have diarrhea as a result of being infected with Eimeria bovis.
Escherichia coli
Environmental contaminant. Pre-milking teat dips are useful for preventing such noncontagious disease as E coli, enterococcus, and Streptococcus sp.(other than S. agalactiae).
Esophageal groove dysfunction
when dysfunctional, milk goes tot he rumen where it is fermented by rumen microbes and converted to volatile fatty acids and lactic acid. This results in rumen acidosis. Number of contributing factors, review feeding program
Ethylene glycol toxicity treatment
4-Methylpyrazole
Faciola hepatica
liver fluke, lesions appear more as tracks and/or hemorrhage. Animals tend to present with abdominal pain or jaundice acutely. Chronically animals become anemic or anorectic.
Farmers lung
episode, allergic disease. Usually, the animal will be housed indoors and be exposed to the allergen; going outside will improve his situation
Fog fever
also called acute bovine pulmonary edema and emphysema. It is one the atypical interstitial pneumonias (diffuse, non-septic lung disease). The lush plants are high in tryptophan wich is subsequently metabolized in the rumen to 3-methyl indole (toxic to the lungs).
Foot and Mouth Disease
Picornavirus
Viral disease of cloven-hoofed animals characterized by fever and vesicles in the mouth and on the muzzle, teats, and feet
Diagnosis: via antigen capture–ELISA or serotyping ELISA of affected epithelium
Can be near 100% fatality
Very contagious
Vaccine available but countries fee of disease usually use slaughter and movement restrictions to control outbreaks
Foot disease location
80% of foot disease involves the digits involves the rear digits, Additionally, approximately 85% of these involve the lateral aspect. This is because they bear the majority of their rear limb weight on the lateral claw in the hind. In the front, cattle put most of their weight on their medical claw.
Hematopinus sp.
Blood sucking genus of louse, and can cause severe anemia. The anemic calves become thin and more susceptible to diseases like pneumonia. 6 legs vs 8 of mites and ticks
