Test 2- Poxviradae

Question 1

Properties of Poxviruses

Answer 1

 Large, sometimes enveloped, DNA viruses with complex structure (symmetry)

 Most poxviruses are pleomorphic, typically brick-shaped.

Possess an irregular surface of projecting tubular or globular structures.

 On the other hand, members of the genus Parapoxvirus are ovoid, covered with long thread-like surface tubules, which appear to be arranged in crisscross fashion, resembling a ball of yarn.

Question 2

Answer 2

top: Orthopoxviruses
bottom: Parapoxviruses

Question 3

Two distinct infectious poxvirus particles exists:

Answer 3

the intracellular mature virus (IMV) and

the extracellular enveloped virus (EEV). Both forms are infectious.

Question 4

The extracellular forms (EEV - extracellular enveloped virions)

Answer 4

 Envelope

 Inner Membrane

has an envelope that they get from the host cytoplasmic membrane- virus comes out via budding

Question 5

Virions that are released from cells by budding, rather than by cellular disruption,

Answer 5

Virions that are released from cells by budding, rather than by cellular disruption, acquire the extra envelope that contains virus encoded-proteins from host cell membrane.

Question 6

Intracellular viral particles (IMV - intracellular mature virions)

Answer 6

Intracellular viral particles (IMV - intracellular mature virions) only have an inner membrane. IMV come out by disruption of host cell and have only inner membrane.

does not have a lipid envelope

infectious

Question 7

Symmetry of Poxviruses

Answer 7

 Do not confirm to icosahedral or helical symmetry. Poxviruses have complex symmetry.

 The virion outer layer encloses a dumbbell-shaped core and two lateral bodies.
 The core contains the viral DNA, together with several proteins.

 Poxviruses have more than 200 genes in their genomes, and as many as 100 of these encode proteins that are contained in virions.

Question 8

genome of poxviruses

Answer 8

The genome of poxviruses consists of a single molecule of linear double-stranded DNA varying in size from 130 kbp (parapoxviruses), to 280 kbp (fowlpox virus), up to 375 kbp (entomopoxviruses).

 Poxvirus genomes have cross-links that join the two DNA strands at both ends.

 Many proteins encoded by the poxvirus genome are enzymes involved in nucleic acid synthesis and virion structural components.

 Also encode proteins that specifically counteract host adaptive and innate immune responses.

Question 9

Replication of Poxvirdae

Answer 9

 Replication of poxviruses occurs predominantly, if not exclusively, in the cytoplasm.

 This is possible, because unlike other DNA viruses, poxviruses have evolved to encode the enzymes required for transcription and replication of the viral genome.

 Following replication, virions are released by budding (enveloped virions), by exocytosis, or by cell lysis- destruction of the cells(non-enveloped virions).

 Most virions are not enveloped and are released by cell lysis.

 Both enveloped and non-enveloped virions are infectious.

 Enveloped virions are taken up by cells more readily and appear to be more important in the spread of virions through the body of the animal. Thus enveloped are more virulent.

Question 10

Antigenic Characteristics

Answer 10

 All poxviruses share group-specific nucleoprotein (NP) –exposed following alkaline digestion of the virus

 Genetic recombination among the viruses within a genus results in extensive serological cross-reactions and cross-protections none between different genera.

 Production of a hemagglutinin by only Orthopoxviruses

Question 11

Stability of Poxviradea

Answer 11

 The virion of a poxvirus is an enveloped particle that differs significantly from other enveloped viruses.

 Unlike other enveloped viruses, poxviruses show a high environmental stability and remain infectious over a period of several months in an ambient environment.

 Due to their low lipid content, they are less sensitive to organic solvents/disinfectants compared to other enveloped viruses.

 Poxviruses show an extraordinary high resistance to drying.

 Can survive for many years in dried scabs or other virus-laden material.

Question 12

Transmission of Poxviradea

Answer 12

Poxviruses are transmitted between animals by several routes:
 Skin: Poxviruses cannot infect intact skin. Contact of infectious material with broken or lacerated skin is a common route of poxvirus transmission.

 Respiratory route: Some poxviruses can be transmitted by the aerosol route. Inhalation of aerosol can result in infection (sheeppox virus).

 Mechanically transmitted( no replication in the arthopod) by biting arthropods (Myxoma virus and avipoxviruses).

Question 13

Pathogenesis and Immunity

Answer 13

 Poxviruses are highly Epitheliotropic, causing cutaneous (skin) lesions.
 Occasionally, poxviruses causes systemic diseases in birds and wild animals.

 Many poxviruses are host specific.
 However, Orthopoxviruses infect a wide range of species.

Question 14

Spread of Poxvirus

Answer 14

 Following introduction into the body, the poxvirus usually gains access to the systemic circulation via the lymphatic system.

 A secondary viremia disseminates the virus back to the skin and to other target organs.

Question 15

Skin Lesions in Poxvirus Infection

Answer 15

 There are degenerative changes in the epithelium.

 Rupture of the pustule can predispose to secondary bacterial infection.

 Ulceration may develop.
 Poxvirus can survive in the dried scabs for many months or years.

Question 16

Genus: Orthopoxvirus

Answer 16

Cowpox

 Distribution: Endemic only in Europe and Asia
 Hosts: Cattle, Wild and Domestic Cats, Humans, Zoo Animals, etc.

 Reservoir Host: Rodents

Is zoonotic, but most humans get this from cats

Question 17

Cowpox in Cattle

Transmission:

Answer 17

 Transmission from cow to cow in a herd is through infected milker’s hands or teat cups.

 Infected farm cats can also transmit the disease.

 Rodents serve as the reservoir and can transmit the disease.

Question 18

Cowpox in Cattle

Economic Importance:

Answer 18

 Losses to farmers due to inconvenience in milking because of soreness of teats and mastitis resulting from secondary bacterial infections.

Question 19

Cowpox in Cattle Clinical Findings:

Clinical Signs

Answer 19

 After an incubation period of 3–7 days, during which cows may be mildly febrile, papules appear on the teats and udder. Sucking calves may develop lesions in mouth.

 Vesicles may not be evident or may rupture readily, leaving raw, ulcerated areas that form scabs.

Question 20

Answer 20

Cowpox ulcer on teat

Question 21

Cowpox in Cats

Transmission:

Answer 21

 Usual route of infection in cats is skin inoculation, probably through a bite or skin wound. Rodents are a common source of infection.
 Transmission by Oro-Nasal route is also possible.
 In exotic felids (cheetahs), viral pneumonia may be evident.

Question 22

Cowpox in Cats

Clinical Signs:

Answer 22

 Primary Lesions:

 Most affected cats have a history of a single primary skin lesion, usually on the head, neck, or a forelimb.

 The primary lesion can vary from a small, scabbed wound to a large abscess.

Question 23

Answer 23

Cow pox in a 4-year-old cat, showing blepharitis (inflammation of eye lids).

primary lesion

Question 24

Answer 24

Cowpox lesion on limb of cat.

primary lesion

Question 25

Cowpox in Cats Clinical Signs:  Secondary Lesions:

Answer 25

 **Approximately 7–10 days after the primary lesion appears, widespread secondary lesions begin to appear.**  Throughout 2–4 days, these develop into discrete, circular, ulcerated papules ~0.5–1 cm in diameter.  The ulcers soon become covered by scabs, and healing is usually complete by ~6 wk.  Many cats show no signs other than skin lesions, but ~20% may develop mild coryza or conjunctivitis.  Complications can result from secondary bacterial infections.

Question 26

Answer 26

Crusting Papular Lesion secondary lesion

Question 27

Answer 27

Multiple Papular Lesions on the Trunk

Question 28

Answer 28

Ulcerative lesions on the upper and lower lip of a cat with poxvirus infection

Question 29

Cowpox in Humans Transmission:

Answer 29

 _Mainly caused by direct contact to ‘‘cuddly’’ cats._  Rarely from rodents and zoo animals.  Virus is not commonly found in cattle, so chances of getting the virus from the cow is very less.

Question 30

Coxpox in humans ## Footnote Clinical Signs:

Answer 30

 **Macropapular lesions first observed on hands and face**. Later develop into vesicular, and then ulcerative lesions.  Enlarged painful local lymph nodes.  Patients may report fever, vomiting, and sore throat.

Question 31

Answer 31

A 16-year-old boy with generalized cowpox

Question 32

Monkeypox In Humans:

Answer 32

Monkeypox is a viral zoonosis with symptoms in humans similar to those seen in the past in smallpox patients.

Question 33

Monkeypox In Monkeys:

Answer 33

In monkeys, the disease is characterized by generalized skin eruptions, developing to papules on the trunk, face, palms and soles.

Question 34

Monkeypox Transmission in Humans:

Answer 34

** Primary infection of humans results** from _direct contact with the blood, bodily fluids, or rashes of infected animals_. In Africa, human infections have been documented through the handling of infected monkeys, Gambian rats or squirrels.  **Secondary transmission is human-to-human,** _resulting from close contact with infected respiratory tract excretions, with the skin lesions of an infected person or with recently contaminated objects._

Question 35

Monkeypox in Humans Distribution:

Answer 35

 Monkeypox occurs primarily in r_emote villages in Central and West Africa,_ near tropical rainforests.  In 2003, it was accidentally introduced in humans into the USA.  Possible source: Rodents from Ghana.  77 Clinical cases, 26% of the patients had to be hospitalized.

Question 36

Monkeypox in Humans Clinical Signs in Humans:

Answer 36

Same as smallpox. **First Phase:** Invasion period (0-5 days): Fever, intense headache, lymphadenopathy (swelling of the lymph node), muscle pain. **Second Phase:** Skin eruption period: Evolution of the rash from maculo-papules (lesions with a flat bases) to vesicles (small fluid-filled blisters), pustules, followed by crusts.

Question 37

Answer 37

monkeypox in humans

Question 38

Other Orthopoxviruses

Answer 38

 Variola (Smallpox in humans)  Camelpox virus (Camels)  Ectromelia virus (Mice, Voles)  Horsepox (Horses, Cattle, Humans)  Rabbitpox virus (Rabbits)  Vaccinia virus (Humans, Cattle, Buffalo, Swine, Rabbits)  Uasin Gishu Disease Virus (Horses)

Question 39

Pseudocowpox's genus and nickname

Answer 39

Parapoxviruses This virus can also infect humans and the condition is commonly referred to as **milker’s nodule.**

Question 40

Transmission of Pseudocowpox

Answer 40

 Source of infection is the infected cattle.  Contaminated milker’s hands, teat cups  Biting insects may transmit the virus  Calves get infected during sucking infected teats(mechnical transmission)  Semen of bulls

Question 41

Pseudocowpox is

Answer 41

Pseudocowpox is a viral skin disease that causes mild sores on the teats and udders of cattle.

Question 42

Pathogenesis of Pseudocowpox

Answer 42

Lesions are characterized by hyperplasia of squamous epithelium

Question 43

Clinical Signs of Pseudocowpox

Answer 43

 Infections are generally mild.  Up to 10 lesions on one teat.  Morbidity rate may reach 100%, but at any given time varies between 5% and 10%, and occasionally up to 50%.

Question 44

Acute lesions of Pseudocowpox

Answer 44

Erythema to Papules to Vesicle or Pustule to Rupture to Thick Scab The thick scab is 0.5 to 25cm in diameter, becomes elevated due to accumulation of granulation tissue. - After 7-10 days, **the scab drops off, leaving a Horseshoe-shaped ring of small scabs surrounding a small wart-like granuloma.****Pox viruses can survive in the scabs in a dry climate for a long time!**

Question 45

Answer 45

Papule from Pseudocowpox on teat

Question 46

Answer 46

Pseudocowpox teats of cow

Question 47

Answer 47

Horseshoe-shaped ring of Pseudocowpox

Question 48

Chronic Lesions of Pseudocowpox

Answer 48

Chronic Lesions:  Commences as Erythema  Yellow-gray, soft scurfy scabs which are rubbed off during milking  Skin is corrugated  No pain- as compared to acute lesions  Lesions may persist for months

Question 49

Diagnosis of Pseudocowpox

Answer 49

 **Horseshoe-shaped ring like lesion are pathognomonic for the disease.**  **Isolation and detection of the virus by various diagnostic laboratory methods from vesicular fluid or from teat skin.**

Question 50

Differential Diagnosis for Pseudocowpox

Answer 50

 Cowpox virus  Bovine herpesvirus ulcerative mammilitis  Vesicular stomatitis  Udder impetigo (bacterial dermatitis characterized by the development of small pustules on the skin of the udder and teats).  Teat chaps and frostbite  Black spot (a form of hyperkeratosis)

Question 51

Pseudocowpox Treatment:

Answer 51

 Removal of scabs  Burn the scabs to prevent environmental contamination  Application of an emollient ointment before milking  Application of astringent preparation after milking.

Question 52

SMALLPOX

Answer 52

killed Rames IV

Question 53

2 subfamilies in Poxviridae

Answer 53

**Subfamily: Chordopoxvirinae (poxviruses of vertebrates)** Genus: Orthopoxvirus Genus: Parapoxvirus Genus: Avipoxvirus Genus: Capripoxvirus Genus: Leporipoxvirus Genus: Suipoxvirus Genus: Molluscipoxvirus (Myxoma virus) Genus: Yatapoxvirus (Yaba Monkey Tumor Virus) **Subfamily: Entomopoxvirinae (poxviruses of insects)**

Question 54

Skin lesion pattern in Pox virus

Answer 54

1. macule- flat red lesion 2. papule- elevated red lesion 3. vesicle- blister, thin walled sack filled with fluid 4. pustule- 5. ulcer- when pustle ruptures- COMPLICATION 6. or pustule will form a scab and then a scar

Question 55

Pseudocowpox Prevention:

Answer 55

 Disinfection. Use iodophor teat dip.  Isolation and treatment of infected cows  Reduce teat trauma, as injuries to skin of teat predisposes to infection.

Question 56

Pseudocowpox in Humans

Answer 56

(The Milker’s Nodule)  Causes a mild skin lesion known as Milker’s Nodule.  Lesions on the hands of dairy farmers milking teats or vets treating infected cows.  Lesions may vary from multiple vesicles to a single, indurated nodule.

Question 57

Answer 57

Pseudocowpox in Humans (The Milker’s Nodule)

Question 58

Contagious Ecthyma

Answer 58

_Synonyms**:**_ **ORF**, Scabby Mouth, Contagious Pustular Dermatitis, Sore Mouth _Etiology:_ Orf virus, Genus Parapoxvirus _Host:_ Sheep and Goats. **Primarily in Lambs and Goat Kids**. Morbidity may reach 100% and case fatality rate 5-15%. _Distribution:_ Worldwide

Question 59

Answer 59

Contagious Ecthyma

Question 60

Contagious Ecthyma  Transmission:

Answer 60

 **Scabs that fall off from the healing lesions contain large number of virus.**  Virus are stable in the environment, i.e. remains highly infectious for long periods under dry conditions.  Contaminated instruments, like docking instrument or ear-tagging plier can transmit the virus.  Spread in a flock is very rapid  Virus infects healthy animals primarily through damaged skin.  Oral lesions in lambs or kids result from nursing dams with teat lesions, and vice-versa.

Question 61

Contagious Ecthyma  Pathogenesis:

Answer 61

 Damage of skin is essential to establish infection.  The skin reaction to viral infection consists of a cellular response with necrosis and sloughing of the affected epidermis and underlying stratum papillare of the dermis.  The cutaneous response to infection includes a delayed-type hypersensitivity reaction and an influx of inflammatory cells .  **The lesions evolve from macule  papule  vesicle  pustule  ulcers  scab formation.**  Immunity is solid, lasts 8 months.

Question 62

Contagious Ecthyma  Clinical signs:

Answer 62

Contagious Ecthyma Clinical signs: **The first lesions develop in the mucocutaneous junction and are accompanied by swelling of the lips.**  From there, lesions spread to the muzzle and nostrils, surrounding hairy skin and the buccal mucosa.  Animal may find it difficult to take food because of oral lesions: thus - Anorexia and Weight loss.

Question 63

Answer 63

Goat: Raised, crusted lesions around the commissure of the lips

Question 64

Answer 64

Goat: Proliferative lesions on lips and mouth

Question 65

Contagious Ecthyma  Clinical signs: kits/severe lesions

Answer 65

 Affected lambs or kids sucking ewes or goats may result in lesions on teats.  This may predispose to secondary bacterial infection, resulting in mastitis.  Severe cases may show lesions in the genitals, coronets (feet) and ears.  Lesions in feet may result in lameness.  Lesions in scrotum may cause infertility.

Question 66

Answer 66

Contagious Ecthyma Lips: Detachment of the Epithelium

Question 67

Answer 67

Teat: Erosion & Scabs Contagious Ecthyma

Question 68

Answer 68

Goat: Proliferative lesion; scabs Contagious Ecthyma

Question 69

Contagious Ecthyma  Clinical signs: Secondary Infections:

Answer 69

 Within 1-4 weeks, the scabs drop off and the underlying tissues heal without scarring.  However, complications can result from secondary bacterial infections, or from invasion of lesions by fly larvae.  A malignant form of the disease has also been observed in sheep.

Question 70

Contagious Ecthyma  Vaccination:

Answer 70

 Vaccine is prepared from suspension of scabs in glycerol saline and is painted onto a small area of scarified skin inside the thigh, where a localized lesion develops.  **In no circumstances should the vaccine be used on farms that do not have a problem with orf.**  You should inspect the lamb 1 week after vaccination for local reactions, which indicates the viability of the vaccine.  **Vaccination do not offer long-lasting immunity, ~1-2 years.**

Question 71

Contagious Ecthyma  Vaccination - when to vaccinate - in problem herds

Answer 71

 In problem flocks/herds, the lambs/kids may need to be vaccinated at 6-8 weeks to help prevent the disease.  In flocks/herds with severe problems, the vaccine may need to be given when the lamb/kid is just 2-3 days old.  Vaccinate pregnant ewes only 7-8 weeks before lambing, not before.

Question 72

Contagious Ecthyma--- ORF in Humans

Answer 72

 Frequent in humans handling sheep and goats, in rural areas.  Macro-papular lesions and large nodular lesions in finger, hand, arm, face and even the penis .  Duration of lesions: 4-9 weeks  Healing occurs without scarring  Secondary bacterial infections of lesions may cause complications.

Question 73

Answer 73

Contagious Ecthyma ORF in Humans

Question 74

Genus: Capripoxvirus

Answer 74

Sheep Pox  Goat Pox  Lump Skin Disease (of cattle)

Question 75

Sheeppox and Goatpox distribution and etiology

Answer 75

_Distribution:_ Endemic in Africa, Asia and parts of Europe _Etiology:_ Members of Genus Capripoxvirus

Question 76

Sheep pox virus (SPV) and goat pox virus (GPV) were once believed to be

Answer 76

Sheep pox virus (SPV) and goat pox virus (GPV) were once believed to be strains of the same virus, but genetic sequencing has now demonstrated them to be separate viruses.

Question 77

Most strains of goat and sheeppox are

Answer 77

Most strains are host specific and cause severe clinical disease in either sheep or goats, while some strains have equal virulence in both species.

Question 78

Can sheep and goat pox be distinguished from each other?

Answer 78

SPV and GPV cannot be distinguished from each other with serological techniques, including viral neutralization.

Question 79

SPV and GPV are also closely related to

Answer 79

SPV and GPV are also closely related to lumpy skin disease virus in cattle (LSDV), but there is no evidence LSDV causes disease in sheep and goats.

Question 80

Sheeppox and Goatpox  Transmission:

Answer 80

 Highly contagious viruses  **Virus enters by respiratory tract and transmission is commonly by aerosol route**  Spread can also occur through mucous membrane or abraded skin, especially by direct contact with **contaminated iatrogenic materials** (iatrogenic)  Virus is present in nasal and oral secretions for several weeks after infection  Virus can survive in dry scabs for months  **Evidence for mechanical transmission by biting arthropods.**

Question 81

Sheeppox  Pathogenesis:

Answer 81

 Sheeppox is a systemic disease.  The incubation period is followed by a leukocyte-associated viremia.  Thereafter, the virus localizes in the skin and other internal organs.  Deposition of immune-complexes results in severe necrotizing vasculitis develop in arterioles and postcapillary venules of the skin (Type-III Hypersensitivity reaction). This results in ischemic necrosis of dermis and overlying epidermis.

Question 82

Sheeppox: 2 forms of the disease

Answer 82

A. Malignantform B. Benignform

Question 83

Answer 83

Necrotizing vasculitis in the ear

Question 84

Sheeppox A. Malignant form:

Answer 84

Seen in lambs and susceptible nonnative breeds, eg. Merino. **Incubation period:** 4-8 days **Initial signs:**  Marked depression and prostration  High fever, salivation, lacrimation  Edema of eyelids  Serous nasal discharge that becomes mucopurulent **Later signs:**  1-2 days after, pox lesions develop on the skin and on buccal, respiratory, digestive and urinary tract mucosae.  In malignant form, pox lesions extend to pharynx, larynx, lungs, vagina, abomasum & spleen. Secondary pneumonia is common. Abortion is rare.  Cutaneous nodules are distributed widely over the body. The nodules, occasionally become vesicular, pustular and finally scab.  **Lesions heal leaving a star-shaped scar, free of hair or wool.**  Mortality rate up to 50%.  Case fatality in lambs up to 100%

Question 85

Sheeppox Benign Form:

Answer 85

B. Benign form:  More common in adults and resistant breeds.  Only skin lesions occur  No, or a very mild systemic reaction

Question 86

Answer 86

Tail of sheep: Sheep Pox lesions

Question 87

Answer 87

Sheeppox lesions

Question 88

Answer 88

sheepox lesions Lesions on the mucosa of the esophagus

Question 89

Sheeppox  Prevention & Control:

Answer 89

 Notifiable disease in most countries of the world.  Prohibition of importation of animals from infected areas.  In case of outbreaks, ring vaccination, destruction of affected flocks and quaratine of infected premises should be instituted.

Question 90

Vaccination for sheepox

Answer 90

 A large variety of commercial vaccines are now available, including a subunit vaccine.  Killed vaccines elicit, at best, temporary protection.  Live attenuated vaccines offer excellent protection \> 1 year.

Question 91

GoatPox

Answer 91

 Goatpox occurs in Africa, Asia and Parts of Europe.  **Goatpox is a reportable disease.**  Disease is clinically similar to sheeppox.  Young kids suffer systemic disease with lesions on skin, respiratory and alimentary mucosae.  Milder form of disease seen in adults.  A flat hemorrhagic form of capripox is seen in some European goats and this has a high case fatality. Lesions in the perineum and scrotum

Question 92

Lumpy Skin Disease

Answer 92

 Etiology: Member of genus Capripoxvirus  Distribution: Enzootic in sub-Saharan Africa and Middle east with recent incursion in Iraq.  Transmission: Arthropod vector (most common). Also direct-contact  Host: **Cattle,** all ages and types are susceptible  Clinical findings: Fever, multiple nodular lesions on skin and mucous membrane, lymphadenopathy. Morbidity reach 80% during epizootics.  Control: Live attenuated vaccines available. Slaughter of affected and in-contact animals.

Question 93

Answer 93

Lumpy Skin Disease

Question 94

Genus: Suipoxvirus

Answer 94

Swinepox

Question 95

Swine pox Etiology, distribution, host, fatality rate

Answer 95

 **Etiology:** Member of genus Suipoxvirus  **Distribution:** Worldwide. Widespread sporadic disease  **Host:** Pigs.  _Generally, benign with low mortality and low morbidity in older pigs._  High case fatality in congenitally infected and very young sucking piglets.

Question 96

Swinepox transmission

Answer 96

 Transmission:  Direct contact associated with skin injury. Virus can survive in scab for years.  Mechanical transmission by pig louse, Haematopinus suis. These lice can carry the virus for weeks or months.  Also mechanical transmission by flies and insects.  There is evidence of transplacental infection of neonatal pigs.

Question 97

Clinical Signs and control of swine pox

Answer 97

- transient fever  Typical pox lesions (erythematous macule  papule  vesicle  pustule  ulcers  scab formation)  Skin lesions may occur anywhere, **but are most obvious on skin of the abdomen and inner aspects of thighs.**  Exudative epidermitis (**greasy pig disease)** and secondary bacterial dermatitis occasionally occur as a sequel to swine pox.  In severe infections, especially in congenitally-acquired pox infections (where piglets are born with or develop lesions over the entire body shortly after birth), lesions may occur in upper respiratory and digestive tracts.  **_Control:_**  Eradication of lice from piggery.  _No commercially available vaccine._

Question 98

Swinepox Erythematous Lesions

Answer 98

lead to

Question 99

Synonyms for Contagious Ecthyma

Answer 99

Contagious Ecthyma (Synonyms: ORF, Scabby Mouth, Contagious Pustular Dermatitis, Sore Mouth)

Question 100

Answer 100

Congenitally Infected Piglet Disseminated skin lesions Swinepox

Question 101

Genus: Avipoxvirus

Answer 101

Fowlpox and other avian poxviruses

Question 102

Fowlpox

Answer 102

 _Etiology:_ Member of genus Avipoxvirus. **First virus to be grown in embryonated eggs**.  _Hosts:_ Highly infectious disease of poultry and turkeys.  _Distribution:_ Worldwide  _Transmission:_ The virus is:  Extremely resistant to desiccation(dryness)  Can survive in exfoliated scabs for long periods.

Question 103

Routes of transmission of Fowlpox

Answer 103

 Virus can be transmitted within a flock through minor wounds and abrasions in mouth, comb, wattles, or skin as a result of fighting, pecking or other injuries.  Mechanically by mosquitoes, lice, and ticks.  Possibly by aerosol route.

Question 104

There are 3 forms of Fowlpox:

Answer 104

 The Cutaneous form (The Dry form)  The Diphtheritic form (The Wet form)  Ocular form

Question 105

Fowlpox  The Cutaneous form (The Dry form):

Answer 105

 Most common form.  Low mortality.  Probably results from injecting by biting arthropods, or mechanical transmission to injured or lacerated skin.  Small papules on comb, wattles, and around the beak.  Lesions occasionally develop on legs, feet and around cloaca.  Nodules become yellowish and progress to a thick scab.  Sharp fall in egg production  In uncomplicated cases, affected birds recover in about 4 weeks.

Question 106

Answer 106

Cutaneous or dry form of fowlpox

Question 107

Fowlpox  The Diphtheritic form (The Wet form):

Answer 107

 The Diphtheritic form (The Wet form):  Probably caused by droplet infection.  I**nvolves infection of mucous membranes of mouth, pharynx, larynx, and sometimes trachea.**  Lesions, as they coalesce, result in a necrotic pseudomembrane, which may cause death by asphyxiation.  Prognosis is poor.

Question 108

Answer 108

Fowlpox  The Diphtheritic form (The Wet form):

Question 109

Ocular Form of Fowlpox

Answer 109

Ocular Form of Fowlpox  Conjunctivitis  Cheesy exudate accumulates under the eyelids

Question 110

Answer 110

Ocular Fowl pox

Question 111

Characterisitic of Avipoxvirus

Answer 111

Bollinger bodies: Eosinophilic Granular Intracytoplasmic Inclusion Bodies. Borrel bodies occur inside Bollinger bodies. Borrel bodies are minute spherical bodies obtained by tryptic digestion of Bollinger bodies.

Question 112

Fowlpox Control  Vaccination:

Answer 112

 **_Vaccination:_**  Modified live fowlpox or pigeon pox virus vaccines of chicken embryo or avian cell culture origin are available commercially.  The use of vaccines is indicated in areas where the disease is endemic, or on premises where infection has been diagnosed.  Vaccines are applied by scarification of skin of thigh.  One vaccine can be administered in drinking water.  In enzootic areas, vaccinate during the first few weeks of life and then again 8-12 weeks later.  Recombinant fowlpox vectored vaccines have been developed.  Control mosquito population and other biting insects.

Question 113

Unclassified Poxviruses Ulcerative Dermatosis of Sheep

Answer 113

 Etiology: Infectious disease of sheep caused by a virus antigenically similar to the ecthyma virus.  Transmission: Virus infection through damaged skin or by coitus  Clinical forms: Regardless of location, lesions are usually ulcers with a raw crater that bleeds easily.

Question 114

Ulcerative Dermatosis of Sheep Manifests in two clinical forms:

Answer 114

Manifests in two clinical forms:  Lip and Leg Ulceration:  Venereal form:

Question 115

Ulcerative Dermatosis of Sheep  Lip and Leg Ulceration:

Answer 115

 Formation of ulcers around the mouth and nose or on the legs (lip and leg ulceration).  Face lesions occur on the upper lip, between the border of the lip and the nasal orifice, on the chin, and on the nose.  Foot lesions are seen anywhere between the coronet and the carpus or tarsus.

Question 116

Answer 116

Ulcerative Dermatosis of Sheep  Lip and Leg Ulceration:

Question 117

Ulcerative Dermatosis of Sheep  Venereal form:

Answer 117

 **Venereal form:**  Venereally transmitted ulceration of the prepuce and penis or vulva.  Rarely, the ulcers may extend to the glans penis so that the ram becomes unfit for natural breeding.  In ewes, edema, ulceration, and scabbing of the vulva have less serious consequences.

Question 118

Answer 118

Balanoposthitis; superficial necrosis of the skin of the mucosa of the prepuce and glans penis Ulcerative Dermatosis of Sheep  Venereal form:

Question 119

Diagnosis of Poxviruses

Answer 119

-Clinical Signs  Sampling Material: Scrapings from skin lesions, Vesicular fluid, Crusts, Scabs  Electron Microscopy: Characteristic morphology and size of poxviruses. Orthopoxviruses are brick shaped. Parapoxviruses are ovoid.

Question 120

Diagnosis of Poxviruses  Histopathology:

Answer 120

Presence of characteristic intracytoplasmic inclusion bodies.  Type-B or Guarnieri inclusion bodies: Most poxviruses induce the presence of type-B or Guarnieri inclusion bodies. These are slightly basophilic and composed of viral particles and protein aggregates.  Type-A or ATI inclusion bodies: Some poxviruses (cowpox and ectromelia virus) induce type-A bodies. A-type inclusions are more strongly eosinophilic.  Bollinger and Borrel bodies in avipoxvirus infection.

Question 121

Answer 121

Guarnieri inclusion bodies

Question 122

Answer 122

Type-A or ATI inclusion bodies

Question 123

Diagnosis of Poxviruses  Inoculation in embryonated egg

Answer 123

Chorioallantoic membrane [CAM] Pock lesions Note: Parapoxviruses do not multiply in chicken embryo

Question 124

Diagnosis of Poxviruses Molecular

Answer 124

 Serological Assays, such as ELISA  Detection of poxvirus nucleic acid by PCR

Question 126

Most humans get cowpox from....

Answer 126

CATS!