Parasitology Flashcards
What are the major tick-borne diseases of cattle in the UK?
- Babesia
- Theileria
What is the life-cycle of babesia?
- Mature tick feeds and becomes infected
- Babesia sexually multiplies in the tick’s intestines
- Asexual multiplication also occurs in multiples tissues
- Vernicules formed (which also divide)
Either - In tick salivary glands
or - In tick ovary and eggs
- Tick feeds on the cow and transmits infection
- Asexual multiplication in Bovine RBCs
What is the pathogenesis of babesiosis?
Infected RBCs rupture leaving free antigen in the blood which then sticks to the surface of other RBCs missdirecting the host immune response while babesia parasites enter other RBCs
What are the consequences of Babeosiosis in naive animals?
Sudden Onset:
- Fever
- Anaemia
- Haemoglobinuria
- Continous diarrhoea
- May result in death (if survie may become a carrier)
What is the epidemiology of Babesiosis?
Mostly in defined endemic areas, sporadic, spring and autumn time affecting hill grazing, over 2 year old, often newly purchased or stressed animals
What is the epidemiology of babesiosis dependent upon?
- Vector (species, population etc)
- Host susceptibility (multi factorial)
What is the host susceptibility of babesiosis dependent upon?
- Age: calves under 9 months are refactory, infected but not sick or Adults are susceptible until infected
- Immunity develops rapidly but may ane
- Carrier state
- Stress
What is enzootic stability versus enzootic instability?
Enzootic stability = Continual re-infection resulting in consistent high level of herd immunity and less disease
Enzootic instability = Infrequent re-infection resulting in some animals with low immunity and more disease
What circumstances will lead to infection of susceptible animals?
- Susceptible animals moving to an infected area
- Infected ticks moving to a clean area
- Infected cattles added to area with clean ticks
- Reduction in tick numbers
- Stress
What is leishmania?
Intra-cellular, protozoan parasites of macrophages causing disease in humans, dogs and wild animals in S. Europe, Africa, Aia and S. america
What is the life-cycle of leishmania?
- Sandfly ingests leishmania
- Intermediate host of sandfly
- Transforms and multiplies in the fly gut and migrates to proboscis
- Dog infected when sandfly bites; leishamnia transforms in the macrophage
Two stages
What is the digenetic life-cycle of leishmania?
- Promastigote
- Amastigote
What is the pathogenesis of leishmania?
- Infection of the vertebrate host = foci of proliferating organisms in skin (cutaneous leishmaniosis) and internal organs (visceral leishmaniosis)
- Very long incubation period (months to years)
- Many dogs that are infected are asymptomatic
- Infection does not equal disease
What are the clinical signs of leishmaniosis in dogs?
Cutaneous:
Shallow skin ulcers e.g. lip, eyelid, ear pinna
Visceral:
- More common
- Chronic wasting condition
- Generalised eczema, hair loss around the yes
- Intermittent fever
- Generalised lymphadenopathy
What is the epidemiology of leishmania?
- Disease dependent on sandfly distibution
- Reservoirs of infection e.g. wild animals such as rats
- Mechanism of transmisson is sandlfy bites or direct contact
