From the SelectedWorks of Hamid Masood. Spring February 17, reo. Hamid Masood. Available at:

Transcription

1 From the SelectedWorks of Hamid Masood Spring February 17, 2014 reo Hamid Masood Available at:

2 REOVIRUS reo: respiratory enteric orphan, early recognition that the viruses caused respiratory and enteric infections incorrect belief they were not associated with disease, hence they we re considered "orphan " viruses

3 First recognized in previously classified as echoviruses >150 species in the family Reoviridae. infect invertebrates, vertebrates and plants, Abs found in all species of mammals tested except whales genera are serologically unrelated. unique feature -- d/s RNA.

4 Family Reoviridae Genus Segments Host Vector Orthoreovirus 10 Mammals None Orbivirus 11 Mammals Mosquitoes, flies Rotavirus 11 Mammals None Coltivirus 12 Mammals Ticks Seadornavirus 12 Mammals Ticks Aquareovirus 11 Fish None Hypexreovirus 10 Mammals None Cypovirus 10 Insect None Fijivirus 10 Plant Planthopper Phytoreovirus 12 Plant Leafhopper Oryzavirus 10 Plant Planthopper Mycoreovirus 11 or 12 Fungi None

5 Bluetongue Sore Muzzle Pseudo Foot-and-Mouth Disease Muzzle Disease

6 Bluetongue Virus Family Reoviridae Genus Orbivirus 24 serotypes worldwid Non-contagious Insect-borne viral disease Ruminants: Primary host is sheep Others infected: Cattle, goats, deer

7 History First described in South Africa Broad distribution worldwide Mediterranean outbreak,

8 Economic Impact Trade restrictions Imposed by BTV-free countries Animals and animal products Greater impact on cattle industry Reservoir for virus

9 Morbidity/Mortality: Sheep Sheep Severity of disease varies Breed Strain of virus Environmental stress Morbidity As high as 100% Mortality Usually 0 to 30%

10 Morbidity/Mortality: Other Species Cattle, goats Morbidity: up to 5% Death is rare Deer, antelope Severe infection Morbidity Up to 100% Mortality 80 to 90% Lasting effects

11 Animal Transmission Biting midges Genus Culicoides Principal vector C. variipennis. sonorensis Ticks, sheep keds In utero Mechanical Venereal?

12 Clinical Signs: Sheep Incubation period: 5 to 10 days Most asymptomatic Oral erosions and ulcerations Tongue Swollen, protruding Cyanotic = blue-tongue Reproductive failure

13 Clinical Signs: Sheep Coronitis Inflammation of coronary band Lameness Painful hooves

14 Clinical Signs Cattle and goats Usually subclinical Erosions, crusts around nose and teats Coronitis Reproductive failure Antelope and deer Hemorrhage, death

15 Post Mortem Lesions Sheep Face and ears edematous Dry, crusty exudate on nostrils Coronary bands hyperemic Internal hemorrhaging Hydranencephaly, is a condition where the brain's cerebral hemispheres are absent and replaced by sacs filled with cerebrospinal fluid.cerebellar dysplasia Cattle Skin: edematous, ulcerated, dry, thick folds Mouth: vesicles, ulcers, necrosis

16 Differential Diagnosis Foot-and-mouth disease Vesicular stomatitis Peste de petits ruminants Malignant catarrhal fever Bovine virus diarrhea Contagious pustular dermatitis Infectious bovine rhinotracheitis Parainfluenza-3 infection Sheep pox Foot rot Actinobacillosis Oestrus ovis infestation Plant photosensitization

17 Sampling Before collecting or sending any samples, the proper authorities should be contacted Samples should only be sent under secure conditions and to authorized laboratories to prevent the spread of the disease

18 Diagnosis Clinical signs History Insect activity Wasting or foot rot Laboratory Virus isolation ELISA, IFA, VN PCR Serology, complement fixation Examination of proteins

19 Treatment No specific treatment Supportive therapy Protection from the elements Fluids and electrolytes Antibiotics Control of vectors by insecticide Reduce transmission Protect susceptible animals

20 Bluetongue in Humans Not a significant threat to humans One human infection documented Reasonable precautions should be taken Disease in humans is not fatal Treatment is supportive care

21 Quarantine Quarantine and movement controls Prevent spread of virus Confine animals indoors (i.e., barn) When vectors are active

22 Disinfection Does not stop virus transmission Cleaning the premises Sodium hypochlorite (bleach) 3% Sodium hydroxide Insect control Pyrethroids Organophosphates

23 Vaccination Available Serotype specific Adverse effects Fetal malformations Recombination New strains of virus

24 African Horse Sickness Virus Non-enveloped RNA Family Reoviridae Genus Orbivirus Latin means ring Nine serotypes (1-9) All viscerotropic Serotype 9 Endemic areas Outbreaks outside of Africa Serotypes 1-8 Limited geographical areas

25 African Horse Sickness Virus Inactivated by Heat (temps greater than 140 o F) ph less than 6, or 12 or greater Acidic disinfectants Rapidly destroyed in carcasses that have undergone rigor mortis

26 Species Affected Equidae Horses, donkeys, mules Zebras Other Camels Dogs

27 Incidence/Prevalence Seasonal Late summer - early autumn Cyclic Drought followed by heavy rains Influences insect breeding Epizootics halted by Frost Lack of long-term vertebrate reservoir Reduced numbers of vectors Control measures Vaccination, vector abatement

28 Morbidity/Mortality Varies with species, previous immunity, form of disease Mortality based on species Horse particularly susceptible Species Mortality Horses 50-95% Mules 50% European and Asian donkeys 5-10% African donkeys and zebras Rare

29 Morbidity/Mortality Mortality based on form of disease Disease Form Mortality Pulmonary form Up to 95% Cardiac form 50% or more Mixed form 70-80% Horsesickness fever Typically recover

30 Transmission Not contagious Vector-borne: Culicoides spp. Culicoides imicola principal vector C. bolitinos C. variipennis Other potential arthropods Viremia in Equidae Horses: 12 to 40 days Zebras, African donkeys: up to 6 weeks

31 Culicoides spp. Biting midges, punkies Extremely small Species identified by wing pattern Habitat Margins of water sources Life cycle: 2-6 weeks Eggs hatch in 2-10 days Females are bloodsucking Greatest biting activity dusk to dawn

32 Incubation Period Experimental: 2-21 days Natural infection: 3-14 days Disease Form Peracute (pulmonary) form Subacute (edematous or cardiac) form Acute (mixed) form Horsesickness fever Incubation Period 3-5 days 7-14 days 5-7 days 5-14 days

33 Clinical Signs Four forms of the disease Peracute (pulmonary) Subacute edematous (cardiac) Acute (mixed) Horsesickness fever Symptomatic infections most common in horse and mules Zebras typically asymptomatic

34 Clinical Signs Infected horses remain viremic for approximately 18 days the fever may be present for another 4 to 8 days, if the animal should live that long. Despite their reduced mortality the viremic stage in donkeys may last for up to 28 days. Zebras appear to be very similar to donkeys in this regard.

35 Clinical Signs First Sign: Fever of 102 F to 106 F, (38.9 C C)

36 Clinical Signs Most Common Sign Congestion of the conjunctivae Severity of congestion is good indication of severity of infection

37 Clinical Signs Lower Eyelid Conjunctivitis African Horse Sickness

38 Clinical Signs: Pulmonary Fever up to 104 F to 106 F Increasingly more rapid respiration and abdominal expiration Respiratory rate may reach per minute Coughing and Sweating %20Images/optphotos/EQsweating.jpg African Horse Sickness

39 Clinical Signs: Pulmonary Horse may appear colicky (getting up and down, and rolling) As pulmonary distress increases: Animal stands with forelegs apart Head extended Nostrils dilated

40 Clinical Signs: Pulmonary Once foam appears in nostrils, death follows rapidly. Animal may drink and eat, even in terminal stages.

41 Clinical Signs: Pulmonary Photo courtesy of Plum Island

42 Clinical Signs: Cardiac At the end of the febrile period, marked swelling of the head and neck may occur

43 Clinical Signs: Cardiac Classic areas for swelling are: Supraorbital fossa Conjunctiva Lips, cheeks, tongue Intermandibular space Laryngeal area Neck, brisket, ventral thorax

44 Clinical Signs: Cardiac Peri-orbital swelling

45 Clinical Signs: Cardiac No edema of the lower parts of the legs occurs Petechial hemorrhages on the ventral surface of the tongue and in conjunctiva may occur As edema progresses, there may be restlessness and signs of abdominal pain and pulmonary edema

46 Clinical Signs: Cardiac Finally, animal becomes prostrate, and dies Again, animal may eat and drink, even in terminal stages

47 Recovery: Cardiac If the disease is not fatal, the edema will subside over 3 to 8 days.

48 Clinical Signs: Mixed Form (acute) Mixture of pulmonary and cardiac forms Signs of one may be predominate The mixed form is more frequently seen at necropsy

49 Acute - Mixed Form Pulmonary and cardiac forms Cardiac signs usually subclinical Followed by severe respiratory distress Mild respiratory signs Followed by edema and death Diagnosed by necropsy Mortality 70-80%

50 Horsesickness Fever Mild clinical signs Characteristic fever (3 to 8 days) Morning remission (undetectable) Afternoon exacerbation Other signs Mild anorexia or depression Congested mucous membranes Increased heart rate Rarely fatal

51 Sudden Death

52

53 Pulmonary edema Pulmonary edema not seen in all cases; Rarely seen in euthanized animals

54 Pulmonary edema

55 Hydropericardium

56 AHS in Other Species Dogs Ingestion of infected horse meat Not usually by insect bites No role in spread or maintenance Dogs usually have the pulmonary form Camels, zebras Inapparent infection

57 Differential Diagnosis Equine viral arteritis Equine infectious anemia Hendra virus infection Purpura hemorrhagica Equine piroplasmosis Equine encephalosis virus Anthrax Toxins

58 Diagnosis Clinical signs Supraorbital swelling is characteristic History Prevalence or exposure to competent vectors Travel from enzootic area Laboratory tests - definitive diagnosis Serotype needed for control measures

59 Laboratory Diagnosis Laboratory tests Virus isolation ELISA, RT-PCR Serology (tentative) Necropsy: spleen, lung, lymph node More than one test should be used AHSV does not cross-react with other known orbiviruses

60 Samples To Collect For virus isolation Blood samples Necropsy samples Spleen, lung, lymph nodes Paired serum samples are recommended Store and transport samples at 39 o F

61 AHS in Humans No natural infection in humans Neurotropic vaccine strains Transnasal infection can lead to encephalitis or retinitis Handle modified live AHS vaccine strains with caution

62 Disinfection Disinfectants Sodium hypochlorite (bleach) 2% acetic or citric acid Killed ph less than 6 ph 12 or greater Rapidly destroyed in carcasses that have undergone rigor mortis

63 Control Quarantine Equidae from endemic areas Asia, Africa, Mediterranean Minimum 60 days at point of entry Vector control and protection Insect repellants Stable in insect-proof housing from dusk to dawn

64 Control Monitor temperature of all equids If febrile Euthanize or isolate in an insect-free stable until cause is determined Vaccination