WikiVet English - User contributions [en]

Theileria

2012-07-08T15:19:43Z

Nlyons: /* References */

{{Taxobox
|name = ''Theileria'' spp
|kingdom = Protista
|sub-kingdom =
|phylum = [[:Category:Protozoa|Protozoa]]
|super-class =
|class =
|sub-class =
|super-order =
|order = Piroplasmorida
|sub-order =
|super-family =
|family = Theileriidae
|sub-family =
|genus = Theileria
|species = ''Theileria parva'' and others
}}
==Introduction==
[[Image:Theileria parva life cycle.jpg|thumb|right|300px|''Theileria parva'' Life Cycle Diagram - Dennis Jacobs & Mark Fox RVC]]
[[File:Theileria_lifecycle.gif|thumb|200px|right|''Theileria'' Lifecycle]]
''Theileria'' species are a group of '''[[Protozoa | protozoan]]''' pathogens causing severe '''lymphatic proliferative disease''' in cattle.

'''''T. parva''''' is the species of most veterinary importance, affecting cattle in Central and Eastern Africa and is the cause of [[East Coast Fever | East Coast Fever]].

Other species cause significant economic losses in the Mediterranean, Middle East and Northern Africa.

==Lifecycle==
''Theileria'' are transmitted via the [[Haemaphysalis spp.|''Haemaphysalis'']] and [[Rhipicephalus spp.|''Rhipicephalus'']] species of '''[[Ticks|tick]] vectors'''.

'''Sporozoites''' enter '''mononuclear''' cells of the host and develop into '''trophozoites''' and multinucleate '''schizonts''' by '''asexual''' reproduction. This process stimulates proliferation of the host cells, allowing further multiplication of the parasite. The local '''[[Lymph Nodes - Anatomy & Physiology|lymph nodes]]''' are first infected.

Schizonts then '''disseminate''' through the '''[[:Category:Primary Lymphoid Tissue | lymphoid tissues]]''' before differentiating into '''merozoites'''.

The merozoites enter the '''[[Erythrocytes | erythrocytes]]''' and form '''piroplasms''' which are '''infective to ticks''' and capable of sexual reproduction.

Sexual reproduction occurs within the nymph and larval stages of the [[Ticks |tick]] and the final infective stage is present within the '''salivary glands''' and is transmitted to mammalian hosts when bloodfeeding.

Transmission in the tick is then '''[[Ticks#Disease Transmission|trans-stadial]]'''.

In endemic areas, '''endemic stability''' is often reached, in which most or all cattle may be infected and be carriers and most ticks are also infected, but young calves gain solid immunity from their immune dams and therefore rarely show clinical disease. This state however takes time to stabilise and will cause significant economic losses in the process.

For more information on ticks as vectors, see [[Tick Disease Transmission]].

==Pathogenesis==
[[Lymphocytes - Introduction|Lymphocytes]] are '''killed''' by invading protozoa and later in disease, '''lymphopoeisis''' is reduced and prevented.

==Diseases==
<big>[[Theileriosis - Cattle |Bovine Theileriosis]]

[[East Coast Fever]]

[[Babesiosis - Horse|Equine Babesiosis]]</big>

==''Theileria parva''==

''T. parva'' is primarily a parasite of '''African buffalo''' and the cause of '''[[Theileriosis - Cattle | Bovine Theileriosis]]''' and '''[[East Coast Fever]]'''. It may be transmitted by a wide range of [[Ticks |tick]] hosts although ''Rhipicephalus appeniculatus'' is the most importnat in the field.

The protozoa form '''rod shaped''' piroplasms within host [[Erythrocytes | erythrocytes]].

Sheep and mice can also be infected.

==''Theileria annulata''==
Also Known As: '''''T. dispar''

''T. annulata'' is also a cause of [[Theileriosis - Cattle |Bovine Theileriosis]]. The parasite infects '''[[Macrophages |macrophages]]''' and '''[[B cells| B Lymphocytes]]''' forming '''round or oval''' piroplasma within host [[Erythrocytes | erythrocytes]].

It also infects sheep and yaks.

==''Theileria equi''==
''Theileria equi'' (formerly ''Babesia equi'') and ''Babesia caballi'' cause [[Babesiosis - Horse|babesiosis in horses]].

{{Learning
|flashcards = [[Piroplasmida_Flashcards|Piroplasmida Flashcards]]
}}

==References==
<references/>
{{CABI source
|datasheet = [http://www.cabi.org/ahpc/?compid=3&dsid=96673&loadmodule=datasheet&page=2144&site=160 Theileria]
|date = 4/06/2011
}}
 

{{review}}
[[Category:Piroplasmida]]
[[Category:CABI Expert Review]][[Category:CABI AHPC Pages]]
[[Category:Nick Lyons reviewed]]

2012-07-08T14:14:58Z

Nlyons: /* Control */

Japanese Encephalitis Virus

2012-07-08T14:03:43Z

Nlyons: /* Introduction */

Also Known As: '''''JE — Japanese B Encephalitis — Hydrancephaly — JEV — JE Virus'''''

==Introduction==
Japanese Encephalitis is caused by a '''[[Culicidae|mosquitoe-borne]] [[Flaviviridae|flavivirus]]''' and affects a wide range of species including ruminants, carnivores, birds and humans.

It is best known for causing reproductive failure in sows and central nervous system disease in horses. Pigs are the main amplifying host.

This disease is '''notifiable''' to the World Organisation for Animal Health [http://www.oie.int/ (OIE)]

JE is '''zoonotic''', epidemics having been recorded in Japan, Korea and India during the mosquito season. Although disease is usually mild or subclinical, fatal encephalitis can develop in children.

==Distribution==
JE has a number of '''insect vectors''', mainly '''[[Culicidae|mosquitoes]]'''. Distribution is restricted to '''South-East Asia'''.

'''Birds''', particularly '''herons''', are '''maintenance hosts''' for JEV while '''pigs''' are '''amplifier hosts.'''

==Clinical Signs==
Key reproductive signs include '''abortion in pregnant sows''', stillbirths, male '''infertility''', lack of libido, small litter sizes and '''heat on palpation''' of the testes and scrotum.

'''Neurological''' disease in '''horses''' features trembling, ataxia, incoordination, opisthotonus, hypermetria, aggression and blindness.

Anorexia, inappetance and ill thrift often accompany other signs.

Infection is usually subclinical in other species.

==Diagnosis==
'''Antibody titres''' can be detected serologically by [[Agglutination|haemagglutination inhibition]], '''[[ELISA testing|ELISA]]''', serum neutralisation and other methods. Antibodies can also be detected in foetuses.

'''Viral antigen''' can be demonstrated in '''brain, placenta and foetuses''' by [[FAT|indirect fluorescent staining '''(IFAT)''']] and avidin-biotin staining.

On '''post-mortem '''of piglets from infected dams, '''hydrocephalus, hydrothorax''', subcutaneous oedema and necrotic foci within the organs are common. The meninges and spinal cord may be congested and cerebellar hypomyelinogenesis has been described. <ref> Morimoto, T. (1969) '''Epizootic swine stillbirth caused by Japanese encephalitis virus. '''Proc symposium on factors producing embryonic and fetal abnormalities, death, and abortion in swine. ''US ARS'', 91-73:137-153</ref>

In male infected pigs, large amounts of '''mucoid fluid''' are present within the [[Testes and Epididymis - Anatomy & Physiology |'''tunica vaginalis''']] and the epididymis and tunic are '''fibrosed'''.

==Treatment==
'''No treatment''' is available in animals.

Human recombinant interferon has been used in human cases of JEV.

==Control==
'''Live attenuated vaccines''' are available against JEV.

Fly control is valuable but impractical.

{{Learning
|flashcards = [[Japanese Encephalitis Flashcards]]
}}

==References==
<references/>
{{CABI source
|datasheet = [http://www.cabi.org/ahpc/?compid=3&dsid=78461&loadmodule=datasheet&page=2144&site=160 Japanese encephalitis] and [http://www.cabi.org/ahpc/?compid=3&dsid=78462&loadmodule=datasheet&page=2144&site=160 Japanese encephalitis virus]
|date =6 June 2011
}}
 

{{review}}
[[Category:Flaviviridae]]
[[Category:Zoonoses]]
[[Category:Pig Viruses]][[Category:Horse Viruses]]
[[Category:Reproductive Diseases - Pig]][[Category:Neurological Diseases - Horse]]

[[Category:CABI Expert Review]][[Category:CABI AHPC Pages]]
[[Category:Nick L]]

Rift Valley Fever

2012-07-08T13:58:41Z

Nlyons: /* References */

Also Known As: '''''RVF'''''

Caused By: '''''Rift Valley Fever Virus — RVFV'''''

==Introduction==
Rift Valley Fever is a '''[[Viruses |viral]] disease''' caused by a [[:Category:Bunyaviridae|bunyavirus]]. It infects cattle, sheep, goats, camels and people.

RVF causes significant '''economic losses in Africa''', both directly through its clinical cases and also as an obstruction to the improvement of breeding stock due to the susceptibility of most imported livestock breeds into endemic areas.

This disease is '''notifiable''' to the World Organisation for Animal Health [http://www.oie.int/ (OIE)]

==Distribution==
The virus is currently only present in '''Africa'''. Huge '''epizootics''' develop, affecting up to '''90%''' of a group, usually in '''5-15 year cycles.'''

RVF is transmitted by a wide range of '''[[Culicidae |mosquitoes]]''' including ''Anopheles spp.'' and ''Culex spp.'' and also ''[[Hyalomma spp.]]'' '''[[Ticks |ticks]]''' and the '''[[Stomoxys calcitrans |stable fly]]'''. Some trans-ovarial transmission is also thought to occur. Climate and weather play a huge role in the emergence and survival of these vectors and thus also in amplification of the virus. The [[Mosquitoes |mosquitoes]] require cloud cover and regular, significant precipitation.

The disease follows the '''rainy season''' in most countries.

==Signalment==
'''Cattle, sheep, goats and humans''' are important hosts. This is due in part to their presence in huge numbers in epizootic areas and therefore ability to greatly '''amplify viral presence''' in a population and transmit to others.

''Bos Taurus'' cattle and other European breed imported into Africa appear highly susceptible to RVF. '''Indigenous breeds''' appear to be '''resistant''' to disease, as do pigs.

Cats, dogs, rats and other rodents seem to be accidental hosts infected by mosquitoes.

Humans working closely with animals or ingesting raw animal products, e.g. in rituals, are most predisposed.

==Clinical Signs==
'''Abortions''' occurring in huge '''storms''' with '''high mortality''' in both neonates and adults are characteristic of the disease. Agalactia may also develop.

In milder clinical cases '''[[Diarrhoea |diarrhoea]] '''may occur and involve melaena and haematochezia.

'''Tachycardia, cyanosis''', petechiation, haemorrhage and clotting defects are haematological consequences of RVF.

The respiratory disease of RVF is non-specific: Purulent nasal discharge, epistaxis, tachypnoea and dyspnoea.

Fever, lymphadenopathy, depression and lethargy usually accompany infection. Hepatitis may cause consequent [[photosensitisation]].

In young animals, '''peracute disease''' causes anorexia, listlessness, collapse and death.

Humans develop '''malarial-like''' disease. High risk individuals include farmers, veterinarians and abattoir staff. Mild disease is most common but severe hepatitis, encephalitis and ocular damage can develop. The usual presentation is of sudden onset fever, myalgia, biphasic behaviour and gastrointestinal disease.

==Diagnosis==
Sudden onset of acute debilitating disease in man and abortion/neonatal death in domestic animals should raise suspicion in the appropriate countries.

'''Viral isolation''' can be performed from '''placenta, foetal liver''' and other tissues.
The virus can also be innoculated into tissue cultures and diagnosed by [[FAT|Fluorescent Antibody Testing '''(FAT)''']] or '''immune-peroxidase''' staining.

Fixed liver samples can be '''immunostained''' and sera from aborted animals examined to confirm viral presence and are both simple and sensitive.

'''IgM [[ELISA testing |ELISA]]''' can also be performed on serum. Virus neutralisation is the prescribed test for international trading of animals <ref> OIE, 2009. http://www.oie.int/fileadmin/Home/eng/Animal_Health_in_the_World/docs/pdf/RIFT_VALLEY_FEVER_FINAL.pdf. Accessed 08/07/2012</ref>

On '''necropsy''', in the viraemic stage, widespread '''petechiae and ecchymoses''' on serous surfaces and organs will be seen and '''extravasated blood''' present in the body cavities.

In older animals, the liver is enlarged and inflamed, with many '''foci of necrosis''' which are bronzed and jaundiced. The gall bladder may also be distended and haemorrhagic. Lymph nodes are enlarged and their germinal centres may be necrotic on closer examination. Extensive subcapsular haemorrhage in the spleen is usual. Renal changes include oedema and congestion. Epicardial and endocardial haemorrhages are often present on the heart.

==Treatment==
No treatment is available.

==Control==
Modified live and inactivated '''[[vaccines]]''' are available. Live vaccination is only recommended in '''non-pregnant''' animals due to its ability to cause abortion and neurological deficits in lambs. In epizootic situations though, this risk may well be worth taking.

Inactivated vaccines are ineffective during epizootics and therefore less widely used than modified live strains.

Mosquito and larval control is extremely valuable. Slow release '''larvicides''' such as '''methoprene''' can be applied to well-defined mosquito breeding areas.

Sentinel cattle are used for epidemiological surveillance, and are tested 2-3months after the seasonal rains.

{{Learning
|flashcards = [[Rift Valley Fever Flashcards]]
}}

==References==
<references/>
{{CABI source
|datasheet = [http://www.cabi.org/ahpc/?compid=3&dsid=66185&loadmodule=datasheet&page=2144&site=160 Rift Valley fever] and [http://www.cabi.org/ahpc/?compid=3&dsid=66184&loadmodule=datasheet&page=2144&site=160 Rift Valley fever virus]
|date =8 June 2011
}}
 

{{review}}
[[Category:Sheep Viruses]][[Category:Cattle Viruses]][[Category:Goat Viruses]][[Category:Zoonoses]]
[[Category:Reproductive Diseases - Cattle]][[Category:Reproductive Diseases - Sheep]][[Category:Reproductive Diseases - Goat]]
[[Category:Alimentary Diseases - Goat]][[Category:Alimentary Diseases - Sheep]][[Category:Alimentary Diseases - Cattle]]
[[Category:Bunyaviridae]]
[[Category:CABI Expert Review]][[Category:CABI AHPC Pages]]
[[Category:Nick Lyons reviewed]]

Rift Valley Fever

2012-07-08T13:47:49Z

Nlyons: /* Diagnosis */

Rift Valley Fever

2012-07-08T13:46:09Z

Nlyons: /* Diagnosis */

Also Known As: '''''RVF'''''

Caused By: '''''Rift Valley Fever Virus — RVFV'''''

==Introduction==
Rift Valley Fever is a '''[[Viruses |viral]] disease''' caused by a [[:Category:Bunyaviridae|bunyavirus]]. It infects cattle, sheep, goats, camels and people.

RVF causes significant '''economic losses in Africa''', both directly through its clinical cases and also as an obstruction to the improvement of breeding stock due to the susceptibility of most imported livestock breeds into endemic areas.

This disease is '''notifiable''' to the World Organisation for Animal Health [http://www.oie.int/ (OIE)]

==Distribution==
The virus is currently only present in '''Africa'''. Huge '''epizootics''' develop, affecting up to '''90%''' of a group, usually in '''5-15 year cycles.'''

RVF is transmitted by a wide range of '''[[Culicidae |mosquitoes]]''' including ''Anopheles spp.'' and ''Culex spp.'' and also ''[[Hyalomma spp.]]'' '''[[Ticks |ticks]]''' and the '''[[Stomoxys calcitrans |stable fly]]'''. Some trans-ovarial transmission is also thought to occur. Climate and weather play a huge role in the emergence and survival of these vectors and thus also in amplification of the virus. The [[Mosquitoes |mosquitoes]] require cloud cover and regular, significant precipitation.

The disease follows the '''rainy season''' in most countries.

==Signalment==
'''Cattle, sheep, goats and humans''' are important hosts. This is due in part to their presence in huge numbers in epizootic areas and therefore ability to greatly '''amplify viral presence''' in a population and transmit to others.

''Bos Taurus'' cattle and other European breed imported into Africa appear highly susceptible to RVF. '''Indigenous breeds''' appear to be '''resistant''' to disease, as do pigs.

Cats, dogs, rats and other rodents seem to be accidental hosts infected by mosquitoes.

Humans working closely with animals or ingesting raw animal products, e.g. in rituals, are most predisposed.

==Clinical Signs==
'''Abortions''' occurring in huge '''storms''' with '''high mortality''' in both neonates and adults are characteristic of the disease. Agalactia may also develop.

In milder clinical cases '''[[Diarrhoea |diarrhoea]] '''may occur and involve melaena and haematochezia.

'''Tachycardia, cyanosis''', petechiation, haemorrhage and clotting defects are haematological consequences of RVF.

The respiratory disease of RVF is non-specific: Purulent nasal discharge, epistaxis, tachypnoea and dyspnoea.

Fever, lymphadenopathy, depression and lethargy usually accompany infection. Hepatitis may cause consequent [[photosensitisation]].

In young animals, '''peracute disease''' causes anorexia, listlessness, collapse and death.

Humans develop '''malarial-like''' disease. High risk individuals include farmers, veterinarians and abattoir staff. Mild disease is most common but severe hepatitis, encephalitis and ocular damage can develop. The usual presentation is of sudden onset fever, myalgia, biphasic behaviour and gastrointestinal disease.

==Diagnosis==
Sudden onset of acute debilitating disease in man and abortion/neonatal death in domestic animals should raise suspicion in the appropriate countries.

'''Viral isolation''' can be performed from '''placenta, foetal liver''' and other tissues.
The virus can also be innoculated into tissue cultures and diagnosed by [[FAT|Fluorescent Antibody Testing '''(FAT)''']] or '''immune-peroxidase''' staining.

Fixed liver samples can be '''immunostained''' and sera from aborted animals examined to confirm viral presence and are both simple and sensitive.

'''IgM [[ELISA testing |ELISA]]''' can also be performed on serum. Virus neutralisation is the prescribed test for international trading of animals.

On '''necropsy''', in the viraemic stage, widespread '''petechiae and ecchymoses''' on serous surfaces and organs will be seen and '''extravasated blood''' present in the body cavities.

In older animals, the liver is enlarged and inflamed, with many '''foci of necrosis''' which are bronzed and jaundiced. The gall bladder may also be distended and haemorrhagic. Lymph nodes are enlarged and their germinal centres may be necrotic on closer examination. Extensive subcapsular haemorrhage in the spleen is usual. Renal changes include oedema and congestion. Epicardial and endocardial haemorrhages are often present on the heart.

==Treatment==
No treatment is available.

==Control==
Modified live and inactivated '''[[vaccines]]''' are available. Live vaccination is only recommended in '''non-pregnant''' animals due to its ability to cause abortion and neurological deficits in lambs. In epizootic situations though, this risk may well be worth taking.

Inactivated vaccines are ineffective during epizootics and therefore less widely used than modified live strains.

Mosquito and larval control is extremely valuable. Slow release '''larvicides''' such as '''methoprene''' can be applied to well-defined mosquito breeding areas.

Sentinel cattle are used for epidemiological surveillance, and are tested 2-3months after the seasonal rains.

{{Learning
|flashcards = [[Rift Valley Fever Flashcards]]
}}

==References==
<references/>
{{CABI source
|datasheet = [http://www.cabi.org/ahpc/?compid=3&dsid=66185&loadmodule=datasheet&page=2144&site=160 Rift Valley fever] and [http://www.cabi.org/ahpc/?compid=3&dsid=66184&loadmodule=datasheet&page=2144&site=160 Rift Valley fever virus]
|date =8 June 2011
}}
 

{{review}}
[[Category:Sheep Viruses]][[Category:Cattle Viruses]][[Category:Goat Viruses]][[Category:Zoonoses]]
[[Category:Reproductive Diseases - Cattle]][[Category:Reproductive Diseases - Sheep]][[Category:Reproductive Diseases - Goat]]
[[Category:Alimentary Diseases - Goat]][[Category:Alimentary Diseases - Sheep]][[Category:Alimentary Diseases - Cattle]]
[[Category:Bunyaviridae]]
[[Category:CABI Expert Review]][[Category:CABI AHPC Pages]]
[[Category:Nick L]]

Rift Valley Fever

2012-07-08T13:38:47Z

Nlyons: /* Clinical Signs */

Also Known As: '''''RVF'''''

Caused By: '''''Rift Valley Fever Virus — RVFV'''''

==Introduction==
Rift Valley Fever is a '''[[Viruses |viral]] disease''' caused by a [[:Category:Bunyaviridae|bunyavirus]]. It infects cattle, sheep, goats, camels and people.

RVF causes significant '''economic losses in Africa''', both directly through its clinical cases and also as an obstruction to the improvement of breeding stock due to the susceptibility of most imported livestock breeds into endemic areas.

This disease is '''notifiable''' to the World Organisation for Animal Health [http://www.oie.int/ (OIE)]

==Distribution==
The virus is currently only present in '''Africa'''. Huge '''epizootics''' develop, affecting up to '''90%''' of a group, usually in '''5-15 year cycles.'''

RVF is transmitted by a wide range of '''[[Culicidae |mosquitoes]]''' including ''Anopheles spp.'' and ''Culex spp.'' and also ''[[Hyalomma spp.]]'' '''[[Ticks |ticks]]''' and the '''[[Stomoxys calcitrans |stable fly]]'''. Some trans-ovarial transmission is also thought to occur. Climate and weather play a huge role in the emergence and survival of these vectors and thus also in amplification of the virus. The [[Mosquitoes |mosquitoes]] require cloud cover and regular, significant precipitation.

The disease follows the '''rainy season''' in most countries.

==Signalment==
'''Cattle, sheep, goats and humans''' are important hosts. This is due in part to their presence in huge numbers in epizootic areas and therefore ability to greatly '''amplify viral presence''' in a population and transmit to others.

''Bos Taurus'' cattle and other European breed imported into Africa appear highly susceptible to RVF. '''Indigenous breeds''' appear to be '''resistant''' to disease, as do pigs.

Cats, dogs, rats and other rodents seem to be accidental hosts infected by mosquitoes.

Humans working closely with animals or ingesting raw animal products, e.g. in rituals, are most predisposed.

==Clinical Signs==
'''Abortions''' occurring in huge '''storms''' with '''high mortality''' in both neonates and adults are characteristic of the disease. Agalactia may also develop.

In milder clinical cases '''[[Diarrhoea |diarrhoea]] '''may occur and involve melaena and haematochezia.

'''Tachycardia, cyanosis''', petechiation, haemorrhage and clotting defects are haematological consequences of RVF.

The respiratory disease of RVF is non-specific: Purulent nasal discharge, epistaxis, tachypnoea and dyspnoea.

Fever, lymphadenopathy, depression and lethargy usually accompany infection. Hepatitis may cause consequent [[photosensitisation]].

In young animals, '''peracute disease''' causes anorexia, listlessness, collapse and death.

Humans develop '''malarial-like''' disease. High risk individuals include farmers, veterinarians and abattoir staff. Mild disease is most common but severe hepatitis, encephalitis and ocular damage can develop. The usual presentation is of sudden onset fever, myalgia, biphasic behaviour and gastrointestinal disease.

==Diagnosis==
Sudden onset of acute debilitating disease in man and abortion/neonatal death in domestic animals should raise suspicion in the appropriate countries.

'''Viral isolation''' can be performed from '''placenta, foetal liver''' and other tissues.
The virus can also be innoculated into tissue cultures and diagnosed by [[FAT|Fluorescent Antibody Testing '''(FAT)''']] or '''immune-peroxidase''' staining.

Fixed liver samples can be '''immunostained''' and sera from aborted animals examined to confirm viral presence and are both simple and sensitive.

'''IgM [[ELISA testing |ELISA]]''' can also be performed on serum.

On '''necropsy''', in the viraemic stage, widespread '''petechiae and ecchymoses''' on serous surfaces and organs will be seen and '''extravasated blood''' present in the body cavities.

In older animals, the liver is enlarged and inflamed, with many '''foci of necrosis''' which are bronzed and jaundiced. The gall bladder may also be distended and haemorrhagic. Lymph nodes are enlarged and their germinal centres may be necrotic on closer examination. Extensive subcapsular haemorrhage in the spleen is usual. Renal changes include oedema and congestion. Epicardial and endocardial haemorrhages are often present on the heart.

==Treatment==
No treatment is available.

==Control==
Modified live and inactivated '''[[vaccines]]''' are available. Live vaccination is only recommended in '''non-pregnant''' animals due to its ability to cause abortion and neurological deficits in lambs. In epizootic situations though, this risk may well be worth taking.

Inactivated vaccines are ineffective during epizootics and therefore less widely used than modified live strains.

Mosquito and larval control is extremely valuable. Slow release '''larvicides''' such as '''methoprene''' can be applied to well-defined mosquito breeding areas.

Sentinel cattle are used for epidemiological surveillance, and are tested 2-3months after the seasonal rains.

{{Learning
|flashcards = [[Rift Valley Fever Flashcards]]
}}

==References==
<references/>
{{CABI source
|datasheet = [http://www.cabi.org/ahpc/?compid=3&dsid=66185&loadmodule=datasheet&page=2144&site=160 Rift Valley fever] and [http://www.cabi.org/ahpc/?compid=3&dsid=66184&loadmodule=datasheet&page=2144&site=160 Rift Valley fever virus]
|date =8 June 2011
}}
 

{{review}}
[[Category:Sheep Viruses]][[Category:Cattle Viruses]][[Category:Goat Viruses]][[Category:Zoonoses]]
[[Category:Reproductive Diseases - Cattle]][[Category:Reproductive Diseases - Sheep]][[Category:Reproductive Diseases - Goat]]
[[Category:Alimentary Diseases - Goat]][[Category:Alimentary Diseases - Sheep]][[Category:Alimentary Diseases - Cattle]]
[[Category:Bunyaviridae]]
[[Category:CABI Expert Review]][[Category:CABI AHPC Pages]]
[[Category:Nick L]]

Rift Valley Fever

2012-07-08T13:38:36Z

Nlyons: /* Clinical Signs */

Also Known As: '''''RVF'''''

Caused By: '''''Rift Valley Fever Virus — RVFV'''''

==Introduction==
Rift Valley Fever is a '''[[Viruses |viral]] disease''' caused by a [[:Category:Bunyaviridae|bunyavirus]]. It infects cattle, sheep, goats, camels and people.

RVF causes significant '''economic losses in Africa''', both directly through its clinical cases and also as an obstruction to the improvement of breeding stock due to the susceptibility of most imported livestock breeds into endemic areas.

This disease is '''notifiable''' to the World Organisation for Animal Health [http://www.oie.int/ (OIE)]

==Distribution==
The virus is currently only present in '''Africa'''. Huge '''epizootics''' develop, affecting up to '''90%''' of a group, usually in '''5-15 year cycles.'''

RVF is transmitted by a wide range of '''[[Culicidae |mosquitoes]]''' including ''Anopheles spp.'' and ''Culex spp.'' and also ''[[Hyalomma spp.]]'' '''[[Ticks |ticks]]''' and the '''[[Stomoxys calcitrans |stable fly]]'''. Some trans-ovarial transmission is also thought to occur. Climate and weather play a huge role in the emergence and survival of these vectors and thus also in amplification of the virus. The [[Mosquitoes |mosquitoes]] require cloud cover and regular, significant precipitation.

The disease follows the '''rainy season''' in most countries.

==Signalment==
'''Cattle, sheep, goats and humans''' are important hosts. This is due in part to their presence in huge numbers in epizootic areas and therefore ability to greatly '''amplify viral presence''' in a population and transmit to others.

''Bos Taurus'' cattle and other European breed imported into Africa appear highly susceptible to RVF. '''Indigenous breeds''' appear to be '''resistant''' to disease, as do pigs.

Cats, dogs, rats and other rodents seem to be accidental hosts infected by mosquitoes.

Humans working closely with animals or ingesting raw animal products, e.g. in rituals, are most predisposed.

==Clinical Signs==
'''Abortions''' occurring in huge '''storms''' with '''high mortality''' in both neonates and adults are characteristic of the disease. Agalactia may also develop.

In milder clinical cases'''[[Diarrhoea |diarrhoea]] '''may occur and involve melaena and haematochezia.

'''Tachycardia, cyanosis''', petechiation, haemorrhage and clotting defects are haematological consequences of RVF.

The respiratory disease of RVF is non-specific: Purulent nasal discharge, epistaxis, tachypnoea and dyspnoea.

Fever, lymphadenopathy, depression and lethargy usually accompany infection. Hepatitis may cause consequent [[photosensitisation]].

In young animals, '''peracute disease''' causes anorexia, listlessness, collapse and death.

Humans develop '''malarial-like''' disease. High risk individuals include farmers, veterinarians and abattoir staff. Mild disease is most common but severe hepatitis, encephalitis and ocular damage can develop. The usual presentation is of sudden onset fever, myalgia, biphasic behaviour and gastrointestinal disease.

==Diagnosis==
Sudden onset of acute debilitating disease in man and abortion/neonatal death in domestic animals should raise suspicion in the appropriate countries.

'''Viral isolation''' can be performed from '''placenta, foetal liver''' and other tissues.
The virus can also be innoculated into tissue cultures and diagnosed by [[FAT|Fluorescent Antibody Testing '''(FAT)''']] or '''immune-peroxidase''' staining.

Fixed liver samples can be '''immunostained''' and sera from aborted animals examined to confirm viral presence and are both simple and sensitive.

'''IgM [[ELISA testing |ELISA]]''' can also be performed on serum.

On '''necropsy''', in the viraemic stage, widespread '''petechiae and ecchymoses''' on serous surfaces and organs will be seen and '''extravasated blood''' present in the body cavities.

In older animals, the liver is enlarged and inflamed, with many '''foci of necrosis''' which are bronzed and jaundiced. The gall bladder may also be distended and haemorrhagic. Lymph nodes are enlarged and their germinal centres may be necrotic on closer examination. Extensive subcapsular haemorrhage in the spleen is usual. Renal changes include oedema and congestion. Epicardial and endocardial haemorrhages are often present on the heart.

==Treatment==
No treatment is available.

==Control==
Modified live and inactivated '''[[vaccines]]''' are available. Live vaccination is only recommended in '''non-pregnant''' animals due to its ability to cause abortion and neurological deficits in lambs. In epizootic situations though, this risk may well be worth taking.

Inactivated vaccines are ineffective during epizootics and therefore less widely used than modified live strains.

Mosquito and larval control is extremely valuable. Slow release '''larvicides''' such as '''methoprene''' can be applied to well-defined mosquito breeding areas.

Sentinel cattle are used for epidemiological surveillance, and are tested 2-3months after the seasonal rains.

{{Learning
|flashcards = [[Rift Valley Fever Flashcards]]
}}

==References==
<references/>
{{CABI source
|datasheet = [http://www.cabi.org/ahpc/?compid=3&dsid=66185&loadmodule=datasheet&page=2144&site=160 Rift Valley fever] and [http://www.cabi.org/ahpc/?compid=3&dsid=66184&loadmodule=datasheet&page=2144&site=160 Rift Valley fever virus]
|date =8 June 2011
}}
 

{{review}}
[[Category:Sheep Viruses]][[Category:Cattle Viruses]][[Category:Goat Viruses]][[Category:Zoonoses]]
[[Category:Reproductive Diseases - Cattle]][[Category:Reproductive Diseases - Sheep]][[Category:Reproductive Diseases - Goat]]
[[Category:Alimentary Diseases - Goat]][[Category:Alimentary Diseases - Sheep]][[Category:Alimentary Diseases - Cattle]]
[[Category:Bunyaviridae]]
[[Category:CABI Expert Review]][[Category:CABI AHPC Pages]]
[[Category:Nick L]]

Akabane Virus

2012-07-08T13:11:18Z

Nlyons: /* References */

Also Known As: '''''Akabane Disease — AKA — Arthrogryposis Hydrancephaly Syndrome — AH Syndrome — Congenital Articular Rigidity — CAR — Congenital Arthrogryposis and Hydrancephaly Syndrome '''''

==Introduction==
Akabane Virus is a member of the [[:Category:Bunyaviridae|'''bunyavirus''']] family, the largest of all the viral families and thus is related to many other diseases including '''[[Rift Valley Fever]] and Nairobi sheep disease.'''

Akabane is a '''teratogenic''' disease, infecting foetuses of cattle, sheep and goats in-utero.

==Distribution==
Tropical and temperate regions, particularly '''Africa''' where it is thought to be present throughout the continent. Seroconversion in Kenya may be as high as 95% in animals of breeding age. In areas where infection prevalence is extremely high, no pathologic effects are seen due to the development of long lasting immunity at an early age.

Akabane virus is transmitted by '''insect vectors, mainly [[Ceratopogonidae|''Culicoides'' midges]]''' but also '''[[Culicidae|mosquitoes]]''' of the ''Aedes ''spp. and ''Culex'' spp. and some species of '''[[Ticks|tick]]'''. Mosquitoes may be solely mechanical vectors as no viral replication has been demonstrated to occur within them unlike Culicodes species.

==Signalment==
Many wild ruminant and equid species have been demonstrated to have antibodies to Akabane virus. Clinical signs though, are only seen in '''cattle, sheep and goats''', but other species may act as amplifying hosts for viral replication.

==Clinical Signs==
'''Arthrogryposis, or joint contracture, ankylosis (inability to straighten the joints), hydrancephaly''' and less commonly, polioencephalomyelitis are among the congenital signs seen in offspring of infected dams due to the teratogenic effects of Akabane. If the jaw is also malformed '''(brachygnathia/prognathia)''' then dysphagia will result. Other congenital lesions seen include '''cleft palate, lordosis and kyphosis.'''

'''Neurological effects''' of the disease manifest somewhat non-specifically as ataxia, recumbency, trembling, opisthotonous, dysmetria, hypermetria, nystagmus and blindness. However, a '''combination of musculoskeletal deformities and neurological deficits is the trademark of Akabane'''.

Akabane can also result in '''abortion or births of stillborns''' if foetal damage is too severe. Infertility and agalactia may also be seen in infected females but this is uncommon.

The pathogenesis and subsequent pathology depends on the '''timing of infection'''; the critical periods are 76-249 days in the cow and 30-53 days in the ewe.

==Diagnosis==
The sudden onset of '''large numbers of abortions and clinical signs in neonatal stock''' as discussed above is highly suggestive of AKA.

'''Viral isolation''' can be attempted from placental caruncles and foetal fluid, membranes or nervous tissue. It can also be performed from serum/plasma of dams during peak vector activity periods.
Virus can be innoculated into cell cultures and identified by '''[[Immunofluorescence]] (IF). PCR''' is also available.

Serologically, many tests are possible but '''[[ELISA testing|ELISA]]''' predominates.

Antibodies to AKA may persist for up to 2 years after infection and often do not indicate clinical disease so are of little clinical use.

CNS lesions will be present in the spinal cord, cerebellum and motor spinal nerves. The '''limbs are usually locked''' in position due to the arthrogryposis and a fibrinous polyarticular synovitis may be present.

==Treatment==
No treatment is available

==Control==
The mainstay is '''vaccination'''. Protection should be at a maximum during '''late spring and early summer''' when vectors are at peak activity. Inactivated and live forms are available.

Vector control and protection/avoidance of animals from vectors are valuable but often impossible due to difficulties identifying vector breeding sites.

{{Learning
|flashcards = [[Akabane Virus Flashcards]]
}}

==References==
<references/>

{{CABI source
|datasheet = [http://www.cabi.org/ahpc/?compid=3&dsid=95162&loadmodule=datasheet&page=2144&site=160 Akabane Virus] and [http://www.cabi.org/ahpc/?compid=3&dsid=95163&loadmodule=datasheet&page=2144&site=160 Akabane Virus Infection]
|date = 20 June 2011
}}
 

{{review}}
[[Category:Bunyaviridae]]
[[Category:Cattle Viruses]][[Category:Sheep Viruses]][[Category:Goat Viruses]]
[[Category:Reproductive Diseases - Sheep]][[Category:Reproductive Diseases - Cattle]][[Category:Reproductive Diseases - Goat]]
[[Category:Musculoskeletal Diseases - Goat]][[Category:Musculoskeletal Diseases - Cattle]][[Category:Musculoskeletal Diseases - Sheep]]
[[Category:Neurological Diseases - Goat]][[Category:Neurological Diseases - Sheep]][[Category:Neurological Diseases - Cattle]]
[[Category:CABI Expert Review]][[Category:CABI AHPC Pages]]
[[Category:Nick Lyons reviewed]]

2012-03-25T19:05:44Z

Nlyons:

Also Known As: '''''[[Theileriosis - Cattle |Theileriosis]] — Corridor Disease — January Disease — [[Theileria|Theileria parva]] — Exotic Theileriosis — Zimbabwe Theileriosis — Fortuna Disease — Murimu wa ngai''''' (African) — '''''Ol tegana''''' (African)

==Introduction==
[[File:T parva.gif|thumb|200px|right|''Theileria parva'' within the blood]]
East Coast fever is a form of [[Theileriosis - Cattle| theileriosis]] caused by ''Theileria parva''.

==Signalment==

Mainly cattle. Also possibly buffalo.

==Distribution==
Mainly in '''tropical''' regions due to reliance upon tick vectors.

==Clinical Signs==
[[File:Theileria lifecycle.gif|thumb|200px|right|''Theileria'' lifecycle]]
Early clinical signs include marked '''pyrexia''', '''leucopaenia''', '''inappetence''', decrease in milk production, '''lymphadenopathy''' and '''palpably hot [[Lymph Nodes - Anatomy & Physiology|lymph nodes]]'''.
As disease progresses, multisystemic signs develop:

'''Cardiovascular''' – Tachycardia, Petechiae and Ecchymoses, possibly [[Anaemia]]

'''Respiratory''' - Nasal discharge, Dyspnoea, Cough

'''Gastrointestinal''' – [[Diarrhoea]] with mucus and/or blood, Inappetance, Hypomotility, Constipation

'''Opthalmological''' – Blindness, Corneal opacity, Discharge, Photophobia, Increased lacrimation

'''Reproductive''' – Abortion, Stillbirths, Agalactia

'''Other''' – Sudden death, [[Icterus]], Marked Pyrexia, Neurological signs, Emaciation

The clinical phase usually lasts '''2-3 weeks''', but death occasionally occurs within a week.

Sub-lethal acute disease may be followed by complete recovery or more usually continue as chronic emaciation and decreased productivity and performance.

===Corridor Disease===

Acute and usually fatal form of East Coast Fever that occurs when ''T. parva'' is transmitted from '''African buffalo''' to cattle. Buffalo appear to be asymptomatic carriers.

===January Disease===

Also Known As – '''''Zimbabwe theileriosis''''' – '''''Fortuna disease'''''

Acute '''strictly seasonal''' fatal form of ''T. parva'' in Zimbabwe. Occurs only from '''December to May''', or more commonly January to March, due to the distribution of its vector, ''[[Rhipicephalus spp.|Rhipicephalus]] appendiculatus''.

Chronic signs such as emaciation and diarrhoea are rarely seen in Corridor disease and January disease due to the short disease course before death.

==Diagnosis==

On post-mortem examination, the lymphoid system is severely damaged and respiratory changes are marked.
Froth is often present in the trachea, bronchi and bronchioles due to pneumonia and pulmonary oedema. Necrosis of the lymphoid tissue may be seen.
Lymph nodes and spleen may be hyperplastic.
The heart is commonly petechiated and ecchymotic.
Petechiae may also be seen throughout the intestines and abomasums in ruminants.

==Treatment==
'''Buparvaquone/Parvaquone''' and '''Halofuginone''' chemotherapy drugs can be effective but their cost often makes them prohibitive.

'''Tetracyclines''' may also be effective against schizonts.

'''Immunisation''' with cryopreserved sporozoites is also possible but carries a risk of causing patent disease.

==Control==
Vaccination with '''cryopreserved sporozoites''' derived from crushed ticks is possible but expensive and not without risks. Vaccination is followed by treatment with long acting oxytetracycline - the so called '''Infection and Treatment Method (ITM)'''.

Control of tick vectors and use of tick resistant breeds is also valuable.

{{Learning
|flashcards = [[East Coast Fever Flashcards]]
}}

==References==
<references/>
{{CABI source
|datasheet = [http://www.cabi.org/ahpc/?compid=3&dsid=62109&loadmodule=datasheet&page=2144&site=160 East Coast fever]
|date =2 June 2011
}}
 

{{review}}
[[Category:Lymphoreticular and Haematopoietic Diseases - Cattle]]
[[Category:CABI Expert Review]]
[[Category:Nick Lyons reviewed]]

2011-10-29T15:29:10Z

Nlyons: /* References */

{{Taxobox
|name = ''Trypanosoma sp''
|kingdom = Protista
|sub-kingdom =
|phylum = [[Protozoa]]
|super-class =
|class =
|sub-class =
|super-order =
|order = Kinetoplastida
|sub-order =
|super-family =
|family = Trypanosomatidae
|sub-family =
|genus = Trypanosoma
|species =
}}
[[File:Trypanosoma brucei.gif|thumb|300px|right|Schematic diagram of ''Trypanosoma brucei'']]
[[Image:Trypanosoma.jpg|thumb|right|150px|''Trypanosoma cruzi'' CDC/Dr. Myron G. Schultz, WikiMedia Commons]]
[[Image:T.cruzi in monkey heart.jpg|thumb|right|150px|''T. cruzi'' in monkey heart Dr. L.L. Moore Jr., WikiMedia Commons]]
[[Image:Triatoma infestans.jpg|thumb|right|150px|''Triatoma infestans'' the Kissing bug - WHO Wikimedia Commons]]
[[Image:Chagas endemic zones 2005.jpg|thumb|right|150px|Chagas endemic zones 2005 - Wikimedia Commons]]
==Introduction==
Trypanosomes are '''elongated unicellular [[Protozoa |protozoal]]''' organisms with an undulating membrane and anterior flagellum.

==Lifecycle==
The trypanosomes are transmitted by '''haematophagous insect''' vectors including the '''[[Glossinidae |tsetse fly]]''' and '''triatomid''' kissing bug.

===Stercorarian===
Stercorarian trypanosomes develop in the '''posterior gut''' of the insect and infective '''metatrypanosomes''' are excreted in the '''faeces''' of the insect onto the '''skin''' of the host.

They can then '''penetrate''' the tissues, gaining access through skin abrasions or mucous membranes. The metatrypanosomes then multiply within the reticulo-endothelial system of the host, later '''disseminating''' throughout the organs invading host cells residing within parasitophorous vacuole. These vacuoles acidify and subsequently release '''trypomastigotes''' into the cell cytoplasm. These then develop into '''amastigotes''' which divide several times eventually transforming back into trypomastigotes that rupture the host cell. From here they may invade other cells or enter the bloodstream where the opportunity may arise to infect the insect vector. The amastigotes may also burst the host cell and invade other cells.

'''''T. cruzi''''', the trypanosome of '''most human importance''', is a typical Stercorarian trypanosome and utilises the '''triatomid “kissing bug”''' as its vector among others. Disease in dogs may also occur.

''T. theileri'' infects cattle and is transmitted by [[Tabanidae |tabanid flies]], [[Stomoxys calcitrans |stable flies]], [[Ticks |ticks]] and [[Culicidae |mosquitoes]].

===Salivarian===
Salivarian trypanosomes develop in the '''anterior gut''' of their vector, the '''[[Glossinidae |Tsetse fly]]'''.

Development occurs in the '''proboscis''' and midgut, forming '''epimastigotes''' which then invade the '''hypopharynx''' and develop into '''trypomastigotes''' and then '''infective metatrypanosomes''' form.

These are then innoculated into the mammalian host through a '''bite''' before a blood meal.

==Pathogenesis==
Trypanosomes '''deplete''' carbohydrates, proteins, lipids and micronutrients from their hosts.

They cause '''haemolytic [[Anaemia |anaemia]]''' when present within the bloodstream.

==Diseases==
[[Trypanosomosis]] affects the lymphoid and haematopoeitic systems of a wide range of hosts.

===Salivarian Species===
''T. brucei'' affects '''all domestic mammals''', including small and farm species, and humans. It also causes a specific [[Protozoal Skin Infections - Donkey|skin disease in donkeys]].

''T. vivax'' infects ruminants, horses and camels causing significant disease.

''T. equiperdum'' causes '''venereal''' equine disease '''dourine'''. It is the only trypanosome that does not immediately require an insect vector for transmission, being spread through coitus.

''T. simiae'' causes fatal pyrexia in '''pigs''' while ''T. congolense'' is milder in the same species.

''T. congolense'' can also affect '''dogs and cats''' causing acute fever, anaemia and neurological signs.

''T. evansi'' also affects all domestic mammals.

===Stercorarian Species===
'''''T. cruzi''''' occurs in '''South America''' where it is transmitted by a triatomid (kissing) bug and infects armadillos, possums and humans. It is known as '''''Chagas’ Disease'''''.
A similar acute disease is thought to be caused by ''T. cruzi'' in dogs in the USA.

''T. melophagum'' and ''T. theileri'' are '''non-pathogenic''' species present in the '''UK''' infecting cattle, buffalo and antelope. Stress and concurrent disease are thought to be contributors to the development of clinical disease from ''T. theileri''.

{{Learning
|flashcards = [[Protozoa_Flashcards#Tropical_Protozoa|Tropical Protozoa Flashcards]]
}}

==References==
<references/>
{{CABI source
|datasheet = [http://www.cabi.org/ahpc/?compid=3&dsid=96918&loadmodule=datasheet&page=2144&site=160 ''Trypanosoma'']
|date = 6 June 2011
}}
 

{{review}}
[[Category:Tropical Protozoa]]

[[Category:CABI Expert Review]]
[[Category:Nick Lyons reviewed]]

2011-10-19T08:14:31Z

Nlyons: /* Publications */

{{UserPage
|Name=Nick Lyons
|Occupation= Veterinary Surgeon 
|School= UK - Cambridge
|Year= 2005
|Email=nlyons@rvc.ac.uk
|Image=
}}

==Biography==

Nick qualified from Cambridge in 2005 having gained a MA in Pathology specialising in immunology, and doing a final year externship at the Ohio State University working on the farm animal clinic. On leaving Cambridge he went to University College Dublin where he completed an internship in Large Animal Medicine which was a predominantly bovine position but with a significant equine component. This led to a residency in dairy cow health and production split between the RVC and Shepton Vet Group, a specialist dairy practice in rural Somerset. During his residency, Nick undertook research projects in novel mastitis diagnostics, uterine torsions and endocrinology of the early post partum dairy cow. He also undertook placements at the University of Wisconsin and University of California - Davis where he received further training in various aspects of dairy herd health. After leaving the RVC he did a year in farm animal practice in Hampshire before doing a MSc in Veterinary Epidemiology split between the RVC and the London School of Hygiene and Tropical Medicine. His MSc theses was on the cost-effectiveness of farm level interventions to reduce the prevalence of VTEC on UK dairy farms in collaboration with the AHVLA. He recently began a PhD at the LSHTM in the department of infectious disease epidemiology on vaccine effectiveness in the control of foot and mouth disease.

==Teaching==

During Nick's internship and residency, he gained a large amount of teaching experience in all years of the veterinary medicine undergraduate course. He continues to offer support to final year students doing their researhc projects and occasionally takes classes as part of the final year farm animal rotation.

==Publications==

Chan SS, Lyons N, McConnell I & Blacklaws BA. Cloning and sequencing of ovine Flt3 ligand
International Journal of Immunogenetics 2007 34(3):167-71

Lyons N, and Gordon P. Investigation of severe abdominal discomfort in a bull. UK Vet 2009. 14(2):34-36.

Lyons NA, Brickell JS, Wilson S, Wathes DC. Association between postpartum concentrations of plasma IGF-I, left displacement of the abomasum and subsequently fertility in the dairy cow. Cattle Practice, 2009. 17(2):131-135.

Lyons NA, Browne E, Aldridge BM. Atypical presentation of sporadic bovine leukosis in a heifer. UK Vet 2010. 15(4):26-29.

Lyons NA, Knight-Jones TJD, Aldridge BM, Gordon P. Bovine Uterine Torsion: A review of 66 cases. Submitted.

Lyons NA, Karvountzis S, Knight-Jones TJD. Aspects of bovine caesareans associated with outcomes. Submitted.

[[Category:UK - Cambridge Graduates]]

[[:Category:Nick L]]

[[:Category:Nick Lyons reviewed]]

[[Help:WikiMarkup Formatting|Shortcut to formatting cheatsheet]]

[[File:Nick Lyons.jpg]]