Tick Borne Diseases of Livestock Flashcards
what are the 4 primary groups of tick pathogens that are important in livestock
- protozoan parasites
- babeseia
- theileria
- rickettsias
- anaplasma
- ehrlichia
what are the two theileria species
theileria annulata
theileria parva
where is theileria annulata a disease of
southern europe
north africa
middle east
asia
where is theileria parva a parasite of
east/central africa
what does theileria annulata cause
tropical theilerosis
what does theileria parva cause
east coast fever
what does transtadial mean
Transstadial transmission is the sequential passage of parasites acquired during one life stage, or stadium, through the molt to the next stage(s) or stadium.
what is the life cycle of theileria annulata/parva
- Tick feeds/inoculates sporozoites
- Sporozoite invades leukocytes to divide — causes cancer like disease
- Lymph node hyperplasia/followed by fever/infection spreads
- Goes to lungs and causes pulmonary edema respiratory distress
- Lymphocytolysis and depressed leucopoeisis causes — leucopenia severe damage to and disorganization of lymphoid system
- Death within 18-26 days
- In T. annulata anemia/jaundice
- Destruction of infected RBC/autoimmune response against RBC
how is theileria diagnosed
lymph node biopsy
ID of parasite in infected leukocyte
Giemsa stain, immunofluorescence PCR
how is theileria treated
buparvaquone
how is theileria controlled
acaracides dipping
vaccination
what is babesia
intraerythrocytic parasite of all domestic animals
what are the mammalian hosts of babesia
cattle
sheep
horses
pigs
dogs
what is the vector of babesia
ixodid (hard) ticks
where is babesia distributed
worldwide
what are the species of babesia that cause babesiosis in northern europe/UK
b. divergens
b. major
what is the vector of babesia divergens
ixodes ricinus
what is the vector of babesia major
haemaphysalis punctata
what is the species of bovine babesiosi in tropical/sub tropcial regions
b bovis
b bigemina
what is the vector of subtropica/tropical babesiosis
rhipicephalus ticks
how is babesia infection transmitted
Infection is acquired by the adult tick and transmitted through the egg to the larvae, nymphs or adults of the next generation
what is the pathogenesis of b divergens and b bigemina
B. Divergens and B. Bigemina — classical hemolytic anemia
Sporozoite infects erythrocytes
Parasites multiply in erythrocytes up to 40% parasitemia
Marked fall in packed red cell volume (<20%) — tissue anoxia — organ damage
Up to 75% of erythrocytes can be destroyed
- Through mechanical disruption or erythrocytes by parasites
- Increased osmotic fragility and phagocytosis of infected and uninfected RBC
what is the pathogenesis of b bovis
Rapid fall in PCV (<20%) when parasitemia is low (<1%)
Due to release of substances that activate plasma components
Increase vascular permeability, vasodilation and intravascular coagulation
Results in circulating stasis and shock followed by destruction of erythrocytes —> tissue anoxia
Slugging of parasite infected cells in capillaries of brain
Anoxia & death: aggression, incoordination or convulsions
how is babesiosis diagnosed
Clinical signs: classic sign of fever
Hemoglobinuria
Time of year: associated with tick activity
Herd and farm circumstances: naive animals
Confirm by blood smear: Giemsa stain acridine orange
Species specific Ab and PCR tests
which animals are most at risk of babesiosis in endemic areas and why
Calves (<1 year) have innate resistance
- In regions where there is high tick activity and parasite is endemic calves get challenged quickly and become immune
- Re-challenged frequently — enzootic stability
Naive adults are at risk
how is bovine babesiosis treated
n endemic area monitor introduced cattle/treat if necessary Imidocarb diproprionate
Frequent dipping against ticks with acaricides
Good biosecurity
Vaccine against Babesia bovis and B. Bigemina
Vaccine against ticks (tickGARD)
what are the species of anaplasma
anaplasma marginale/centrale
where is anaplasma marginale/centrale present
south west USA moving into nothern states
how is anaplasma marginale/centrale transmitted
transtadial
20 species of tick (dermacentor in USA)
biting flies – mechanical
bovine transplacental transmission can occur
what does bovine anaplasmosis cause
severe hemolytic anemia
rising fever occurs with rising parasitemia (up to 70% of erythrocytes can be destroyed)
Pale mucous membranes/loss of co-ordination/abortion/death
No hemoglobinuria
how is bovine anaplasmosis treated
oxytetracycline
how is bovine anaplasmosis controlled
prevent stress and remove carriers
vaccinate animals (killed experimental vaccine in USA)
what disease does ehrlichia (cowdria) ruminantium cause
heartwater disease
what does ehrlichia (cowdria) ruminantium cause
severe febrile illness of calves and lambs
where is ehrlichia (cowdria) ruminantium located
sub saharan africa
caribbean
how is ehrlichia (cowdria) ruminantium transmitted
three host ornate tick amblyomma
transtadial
what is the pathogenesis of ehrlichia (cowdria) ruminantium
Multiplies in vascular endothelial cells — circulates in neutrophils
Vascular injury — edema
Acute cases manifest as sudden onset of fever: followed by nervous signs
Constant lip chewing, licking, circle with high stepping gait
Animals die while undergoing massive convulsions
Brain edema
how is ehrlichia ruminantium treated
vaccination
Infection with live parasite then treat with tetracycline
what are tick borne diseases of equines (3)
Equine piroplasmosis
- Babesia caballi
- Theileria equi
Anaplasmosis
- A. phagocytophilum
Lyme disease
- B. Burgdoferi
what does equine piroplasmosis cause
Fever
Anemia
Jaundice
Hemoglobinuria
how is equine piroplasmosis treated
imidocarb diproprionate
