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==''Trypanosoma''==
==''Trypanosoma''==
*Protozoal parasites found in the blood and tissues of vertebrates
*Worldwide distribution
*Causes sleeping sickness in humans
*Particularly affect sub-Saharan Africa
**Affect cattle production
**Cause Nagana (depression)
*Divided into two groups depending on the mode of development of the insect vector
**'''Salivarian'''
***Multiply in the foregut
***Transmitted via innoculation via feeding
**'''Stercorarian''''
***Multiply in the hindgut
***Transmitted via contamination of wounds with insect faeces
'''Life Cycle'''
'''Life Cycle'''
*Undergo morphological transformations in intermediate host before becoming infective for the next host
*Blood-sucking [[Biting Flies|flies]] ingest trypanosomes whilst taking a blood meal from an infected animal
**Trypanosomes multiply first in the gut of the [[Biting Flies|fly]]
*Salivarian trypanosomes are transmitted by [[Biting Flies#Glossinidae|Tsetse flies]]
**Trypanosomes pass foward to the salivary glands where they transform into the infective stage
**Innoculated with saliva when [[Biting Flies#Glossinidae|Tsetse fly]] next feeds on a host
*Stercorarian trypanosomes are transmitted by triatomid bugs, [[Biting Flies#Tabanidae|tabanids]] and [[Biting Flies#Melophagus spp.|keds]]
**Trypanosomes pass back to the rectum
**Next host is infected when skin wounds are contaminated with infected [[Insecta|insect]] faeces
'''Pathogenesis'''
'''Pathogenesis'''
*Salivarian
**Causes wasting disease in cattle (nagana)
**Sleeping sickness in humans
*Stercorarian
**''T. cruzi'' most important in veterinary medicine
***Occurs in South America
***Infects armadillos, possums and humans
***Causes Chagas Disease
**Transmitted by a triatomid (kissing) bug
**Chronic infections are often fatal causing heart failure
**Non-pathogenic species are transmitted by [[Biting Flies#Tabanidae|tabanids]] and [[Biting Flies#Melophagus spp.|keds]]
***''T. theileria'' and ''T. melophagium''
*Enlarged [[Lymph Nodes - Anatomy & Physiology|lymph nodes]] and [[Spleen - Anatomy & Physiology|spleen]]
**Causes lymphoid exhaustion
*Anaemia
**Red blood cells removed from circulation
*Degeneration and inflammation of multiple organs
**E.g. Skeletal muscle, myocardium and CNS
'''Epidemiology'''
'''Epidemiology'''
'''Diagnosis'''
'''Diagnosis'''
*Demonstrate trypanosomes in blood
**Giemsa stained smears
**Fresh blood films
***Motile trypanosomes
**Haematocrit tube
***Motile trypanosomes at the plasma/buffy coat interface
'''Control'''
'''Control'''
*[[Biting Flies#Glossinidae|Tsetse fly]] control
**Spraying and trapping
*Prophylactic drug treatment
**Change drug group periodically to decrease the chances of resistance occuring
**May lead to protective immunity but livestock will still be susceptible to heterologous challenges
*Barrier fences and buffer zones
**Separate livestock and wild animals
*Trypanotolerant livestock
'''Other trypanosomes'''
'''Other trypanosomes'''
*Mechanically transmitted by [[Biting Flies|biting flies]]
**E.g. Surra affecting horses and camels in North Africa, Asia and South America
**''T. equinum'' in South America
**''T. evansi'' in Asia
*Venerally transmitted
**E.g. Dourine
***Transmitted by ''T. equiperdum''
***Causes genital and abdominal oedema, emaciataion and CNS signs
***Affects horses and donkeys in Africa, Asia, Central and South America
*Non-pathogenic species occur in the UK
**In sheep caused by ''T. melophagium''
**In cattle caused by ''T. theileri''
==''Leishmania''==
==''Leishmania''==