Difference between revisions of "Trypanosomosis"

Revision as of 18:11, 3 June 2011

Also Known As — Nagana—Typanosomiasis

Introduction

Schematic diagram of Trypanosoma brucei

Trypanosomosis is a disease caused by protozoan pathogens of the genus Trypanosoma.

Trypanosomosis causes a wasting disease in cattle and sleeping sickness in humans.

T. cruzi is the most important species in veterinary medicine.

Causative Organisms

T. cruzi occurs in South America where it is transmitted by a triatomid bug and infects armadillos, possums and humans. It is known as Chagas’ Disease.

T. brucei and T. Equiperdum affect horses, the latter causing venereal dourine.

T. simiae causes fatal pyrexia in pigs while T. Congolense is milder in the same species.

T. brucei and T. Congolense can also affect dogs and cats causing acute fever, anaemia and neurological signs.

T. brucei causes skin infections in donkeys.

T. melophagum and T. Theileri are non-pathogenic species present in the UK.

Transmission

Trypanosomiasis is spread by Tsetse flies.

Clinical Signs

Clinical disease varies widely with death occurring from 1 week to months after infection. T. vivax is known for is rapid mortality while T. brucei and T. congolense hosts often survive for prolonger periods. Infection of large numbers of insect vectors is common in these circumstances

Ruminants

Enlarged lymph nodes and spleen. Later in the disease course the lymph nodes and spleen shrink due to lymphoid exhaustion.

Haemolytic anaemia is a cardinal feature.

Chronic infection causes heart failure and associated signs and death.

Plasma cell hypertrophy and hypergammaglobulinaemia are evident on haematology and biochemistry.

Emaciation

Abortion and infertility

Horses

Oedema of the limbs and genitalia. Dourine – genital and abdominal oedema and neurological signs.

Donkeys

Skin infections

Dogs and Cats

Pyrexia, myocarditis, myositis, corneal opacity and neurological signs.

Diagnosis

Trypanosomes in blood

Microscopic identification on trypanosome parasites in the host blood on a smear with Giemsa staining.

Motile trypanosomes may be demonstrable in a haematocrit tube at the plasma: buffy coat interface.

Treatment

A variety of drugs can be used to treat trypanosomiasis including diminazene, homidium, isometadium, suramin and melarsomine.

Control

Separation of livestock and wild animals is effective but difficult.

Use of trypanotolerant livestock breeds. Tsetse fly control by sprays, traps etc

Prophylactic drug therapy with quinapyramine or homidium is effective.

References

Merck Veterinary Manual, Tetse-transmitted Trypanosomiasis accessed online 03/06/2011 @ http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/10413.htm

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-{{OpenPagesTop}}
+Also Known As — '''''Nagana'''''—'''''Typanosomiasis'''''
-Also Known As: '''''Nagana — Trypanosomiasis — Chagas' Disease — Sleeping Sickness — Parrot Sickness  —  Dourine'''''
 ==Introduction==
-[[File:Trypanosoma.jpg|thumb|200px|right|''T.cruzi''. Wikimedia Commons]]
+[[File:Trypanosoma brucei.gif|thumb|300px|right|Schematic diagram of Trypanosoma brucei]]
-Trypanosomosis is a disease caused by '''[[Protozoa | protozoan]]''' pathogens of the genus [[Trypanosoma]]. They are '''obligate parasites''' and can infect mammals, birds, reptiles, amphibians and fish.
+Trypanosomosis is a disease caused by [[Protozoa | protozoan]] pathogens of the genus Trypanosoma.
+Trypanosomosis causes a wasting disease in cattle and sleeping sickness in humans.
-Trypanosomes are divided into two categories depending upon their lifecycle:
+T. cruzi is the most important species in veterinary medicine.
-'''Stercorarian trypanosomes''' develop within an '''insect''' vector and are transmitted to mammals in the faeces of the vector.
-'''Salivarian''' trypanosomes develop within '''[[Glossinidae |tsetse flies]]''' and mammals are infected through their bites.
+==Causative Organisms==
+''T. cruzi'' occurs in '''South America''' where it is transmitted by a triatomid bug and infects armadillos, possums and humans. It is known as ''Chagas’ Disease''.
-For more information about the various species see [[Trypanosoma]] page.
-Trypanosomosis causes a '''wasting disease''' in cattle and '''sleeping sickness''' in humans.
+''T. brucei'' and ''T. Equiperdum''  affect horses, the latter causing venereal '''dourine'''.
-'''''T. cruzi''''' is the cause of Chagas disease in humans but can also  affect dogs, cats and pigs. ''T. vivax'' and ''T. congolense'' are the main pathogens of cattle. In horses, ''T. equiperdum'' is the cause of '''Dourine'''.
+''T. simiae'' causes fatal pyrexia in '''pigs''' while ''T. Congolense'' is milder in the same species.
-Trypanosomosis is '''notifiable''' to the World Organisation for Animal Health [http://www.oie.int/ (OIE)].
+''T. brucei'' and ''T. Congolense'' can also affect '''dogs and cats''' causing acute fever, anaemia and neurological signs.
-==Signalment==
+''T. brucei'' causes [[Protozoal Skin Infections - Donkey|skin infections in donkeys]].
-Some breeds appear '''trypanotolerant''' and able to resist clinical disease and anaemia, such as African buffalo and N’dama and Keteku cattle.
-'''Calves''' less than a year old are more resistant than adults, but lambs and kids appear more susceptible to ''T. congolense'' infections.
+''T. melophagum'' and ''T. Theileri'' are '''non-pathogenic''' species present in the '''UK'''.
-Cattle 6-9yrs old appear most susceptible to trypanosomosis.
 ==Transmission==
-[[File:Tsetse fly.jpeg|thumb|200px|right|Tsetse fly]]
+Trypanosomiasis is spread by [[Glossinidae|Tsetse flies]].
-Trypanosomosis is spread by '''[[Glossinidae|Tsetse flies]]''' and other insect vectors.
-[[File:Triatoma infestans.jpg|thumb|200px|right|Triatomid - "kissing bug". (WHO - Wikimedia Commons)]]
-[[Tabanidae | Horse flies]]  and [[Stomoxys calcitrans |stable flies]] can also act as mechanical vectors for some [[Trypanosoma | ''trypanosoma'']] species, but the parasites cannot undergo lifecycle development within these hosts.
-''T. vivax'' and ''T. evansi'' are reported to achieve transplacental transmission. <ref>Ikede, B. O., Loso, G. J.(1972). '''Hereditary transmission of Trypanosoma vivax'''. Brit Vet J, 128:i-ii</ref>
-==Distribution==
-Worldwide
-''T. brucei'', ''T. uniforme'', ''T. congolense'' and ''T. simiae'' are found only in the tsetse fly belt of Africa due to the restricted spread of their vector. ''T. vivax'' is more widespread occurring in Sub-saharan Africa as well as South America.
 ==Clinical Signs==
-Clinical disease varies widely with death occurring from 1 week to months after infection.
+Clinical disease varies widely with death occurring from 1 week to months after infection. ''T. vivax'' is known for is rapid mortality while ''T. brucei'' and ''T. congolense'' hosts often survive for prolonger periods. Infection of large numbers of insect vectors is common in these circumstances
-''T. vivax'' is known for its rapid mortality while ''T. brucei'' and ''T. congolense'' hosts often survive for prolonged periods. Infection of large numbers of insect vectors is common in these circumstances.
-Significant losses may also be caused by increased susceptibility and prevalence of other concurrent diseases where trypanosomosis is present.
+===Ruminants===
+Enlarged '''[[Lymph Nodes - Anatomy & Physiology|lymph nodes]]''' and '''[[Spleen - Anatomy & Physiology|spleen]]'''.
+Later in the disease course the [[Lymph Nodes - Anatomy & Physiology|lymph nodes]] and [[Spleen - Anatomy & Physiology|spleen]] shrink due to '''lymphoid exhaustion'''.
-Multisystemic signs can be seen in any species so diagnosis from clinical examination is often impossible as no pathognomonic signs are evident.
+Haemolytic anaemia is a cardinal feature.
-===Ruminants===
+Chronic infection causes '''heart failure''' and associated signs and death.
-Enlarged '''[[Lymph Nodes - Anatomy & Physiology|lymph nodes]]''' and '''[[Spleen - Anatomy & Physiology|spleen]]''' are the most common sign. Later in the disease course the lymph nodes and spleen shrink due to '''lymphoid exhaustion'''.
-'''Haemolytic anaemia''' is a cardinal feature. Chronic infection causes '''[[:Category:Heart Failure|heart failure]]''' and associated signs and death.
+Plasma cell hypertrophy and hypergammaglobulinaemia are evident on haematology and biochemistry.
-Plasma cell hypertrophy and '''hypergammaglobulinaemia''' are evident on haematology and biochemistry.
+Emaciation
-Emaciation, '''abortion''', premature births and infertility are features, and '''orchitis''' in males reduces fertility.
+Abortion and infertility
 ===Horses===
-'''Oedema''' of the '''limbs''' and '''genitalia''' is very common.
+'''Oedema''' of the '''limbs''' and '''genitalia'''.
+'''Dourine''' – genital and abdominal oedema and neurological signs.
-'''Dourine''' – genital and abdominal '''oedema''', paraphimosis, '''urticarial plaques''' known as “silver dollar spots” and neurological signs may all be present. The disease is usually mild and recurrent but can be fatal.
 ===Donkeys===
-See [[Protozoal Skin Infections - Donkey|donkey skin infections]] page for details.
+[[Protozoal Skin Infections - Donkey|Skin infections]]
 ===Dogs and Cats===
-'''Pyrexia''', myocarditis, '''myositis''', corneal opacity and occasionally '''neurological signs''' may all be present.
+'''Pyrexia''', myocarditis, '''myositis''', corneal opacity and '''neurological signs'''.
 ==Diagnosis==
 [[File:Trypanosomes blood.gif|thumb|200px|right|Trypanosomes in blood]]
-Microscopic identification on trypanosome parasites in the host blood on a '''smear''' with Giemsa staining is commonly performed. Where low levels of parasitaemia are present, filtration or haemolysis of a whole blood sample may be required and motile trypanosomes may be demonstrable in a haematocrit tube at the '''plasma: buffy coat''' interface.
+Microscopic identification on trypanosome parasites in the host blood on a '''smear''' with Giemsa staining.
-On '''post-mortem''' examination, carcasses are often pale and oedematous due to anaemia and emaciation. Degenerative lesions can be found on the heart, liver, lymph nodes, testes, brain, conjunctiva, cornea, spleen, kidney and endocrine organs.
+Motile trypanosomes may be demonstrable in a haematocrit tube at the '''plasma: buffy coat''' interface.
-Many other seroimmunological techniques are also available variably in laboratories.
 ==Treatment==
-A variety of drugs can be used to treat trypanosomosis including '''diminazene, homidium, isometadium, suramin''' and '''melarsomine'''.
+A variety of drugs can be used to treat trypanosomiasis including '''diminazene''', '''homidium''', '''isometadium''', '''suramin''' and '''melarsomine'''.
-'''Diminazene aceturate''' is most commonly used and is frequently '''curative'''. It however causes frequent local reactions in horses so should be given in multiple deep muscular sites and massaged well. The drug is also ''contraindicated in dogs and camels'' due to vascular damage. Diminazene also has a prophylactic effect for up to 3 months.
-'''Resistance''' is increasing in Africa to trypanosomicidal drugs so multiple treatments may be required in some areas.
 ==Control==
-'''Separation''' of livestock and wild animals is effective but difficult.
-Use of '''trypanotolerant''' livestock breeds is the only option is some areas where economic restraints prevent constant treatment and control.
+Separation of livestock and wild animals is effective but difficult.
-'''[[Glossinidae |Tsetse fly]] control''' by sprays, traps, dips and release of sterile male flies is effective but expensive and time-consuming.
+Use of trypanotolerant livestock breeds.
+[[Glossinidae | Tsetse fly]] control by sprays, traps etc
-Prophylactic drug therapy is also effective but costly.
+Prophylactic drug therapy with quinapyramine or homidium is effective.
-{{Learning
-|flashcards = [[Trypanosomosis Flashcards]]
-}}
 ==References==
 <references/>
+Merck Veterinary Manual, '''Tetse-transmitted Trypanosomiasis''' accessed online 03/06/2011 @ http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/10413.htm
-Merck Veterinary Manual, '''Tsetse-transmitted Trypanosomiasis''' accessed online 03/06/2011 @ http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/10413.htm
+[[Category:To Do – Steph]]
-{{CABI source
-|datasheet = [http://www.cabi.org/ahpc/Default.aspx?site=160&page=2144&LoadModule=datasheet&CompID=3&dsID=60779  trypanosomosis]
-|date = 5 June 2011
-}}
-<br><br><br>
-{{Nick Lyons
-|date = 15 October 2011}}
-{{OpenPages}}
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-[[Category:CABI Expert Review Completed]][[Category:CABI AHPC Pages]]
-[[Category:Nick Lyons reviewed]]
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