emerging viruses in companion animals. pesavento - viral emergence.pdf · patricia a. pesavento...
TRANSCRIPT
Patricia A. Pesavento [email protected]
Emerging viruses in Companion Animals Consider diagnostics, pathogens, and pathogenesis
Outline of conversation1.!Emergence!pathways!
! Viral!evolution:!Parvovirus!! Ecosystem!impact!
2.!Canine!in9luenza!
3.!Diarrhea,!polymicrobial!disease,!and!!!!diagnostic!dilemmas!(Circo,!Boca,!Astro,!Corona,!Giardia,!Campy!etc)
Viral evolution will happen. You are the most likely person to discover changes.
Our!pets!are!a!relatively!unguarded!interface!15!million!dogs/cats!vs.!9!million!cows,!280!vs.!3000!veterinarians
Polymicrobial!infections
Stress
Impact!of!medical!intervention
Mechanisms of Emergence
! Virus ! changes in virulence, episodic
epidemics, species-jumping ! Host
! Breeds, medicine, and contact ! Environment
! Anthropogenic
! Viral Discovery
Help the individual animal, help the herd, identify emergence, identify zoonoses
Why do diagnostics?
Having a diagnosis will result in a better prognosis.
REGARDLESS OF WHETHER OR NOT THERE IS A CURE
• pain&• duration&of&disease&• time&to&death&
Viral&Discovery&
Method Detection Limitation
PCR specific, sensitive, standard
Requires knowledge of target pathogen
Microarray broad range of pathogens (family)
not broadly available, cost
Metagenomics (massive sequencing) almost unbiased depends on informatics,
costly, slow
EM unbiased not broadly available, not always specific
Culture bacteria biased
Serology broad range of systemic pathogens exposure only
Anthony S J et al. mBio 2013
Viral!discovery!curve
Estimate!that!mammals!alone!harbor!at!least!320,000!viruses!waiting!to!be!discovered
Interpretation of results
quantitative PCR Based on the intact presence of genetic material Highly sensitive Highly specific Fast turn-around time for results Many different types of biologic samples can be interrogated
Organism Salmonella Giardia Canine coronavirus
Canine parvovirus 2
Canine distempervirus Campylobacter
Clinical signs Fever, sepsis,
anorexia, may or may
not be hemorrhagic
Acute/chronic/ intermitt
ent
Acute diarrhea, with vomiting can have fever
Acute, hemorrhagic
Vomiting, diarrhea
Prevalence
Found at LOW rates in
both non-diarrhetic
and diarrhetic animals (<2%)
Overall 8%
50% in puppies
up to 100% in shelters
15-26% healthy 60% in non-diarrhea in a
shelter 73% in diarrhea
in a shelter
High in identified
cases (young, hemorrhagic
diarrhea)
Not done. GI can be presenting sign
Clinical significance significant,
zoonotic potential
can treat, but don’t re-
test
NOT significant usually, but can
besignificant significant
also….Campylobacter coli, C.p A gene, C. p E gene, Cryptosporidium
*
Diagnostics of microbes: Microbiology in the post-genomics era
Campylobacter!spp!were!isolated!from!5%!dogs!with!diarrhea!and!28%!control!dogs...
No!signi9icant!difference!(%!dogs)!Campylobacter!isolated!from!young!dogs!with!and!without!diarrhea.!
58%!of!healthy!dogs!and!97%!of!diarrheic!dogs!shed!detectable!levels!of!Campylobacter!spp.
Some spp. of Campylobacter are significantly associated with diarrhea, and polymicrobial infections can be important
50 % mortality severe disease
increased shedding
EPEC
= inapparent-mild disease
1010 cfu
Pakpinyo et al, Avian Dis, 2003
tcv
7 days EPEC
104 cfu
=
Polymicrobial infections
Host susceptibilityEnvironmental interaction is unique for every animal Anthropogenic challenges Movement (animals=mismatch.. and pathogens) Bottlenecks
eg a simultaneous outbreak of MDR Salmonella Schwartzengrund in US, Denmark, Thailand
Animal-Human Interface
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KF Hurley
• Emergence of Virus Escape Mutants after Immunization with Epitope Vaccine G. Weidt, et al J Virol. (1995 )November; 69(11): 7147–7151!
• Influenza Type A Virus Escape Mutants Emerge In Vivo in the Presence of Antibodies to the Ectodomain of Matrix Protein 2
Darya Zharikova et al J Virol, June (2005), p. 6644-6654, Vol. 79, No. 11!
• Genogrouping of Vaccine Breakdown Strains of Feline Calicivirus in Japan Ohe et al Vet Res Comm, 31 (2007) 479-507!
Is Vaccination Driving Emergence?
Case: 1 year old Beagle-cross
1012 C. S. Potten and M. Loeffler
Mouse 2x1O8 cells shed/small intestine/dayMan «1011 cells shed/small intestine/day
1400cells/villus/day
300 cells/crypt/day/JM/J
VILLUS3500 cells 0
Tc»24h
(P) Paneth cells
C.S. Potten, 1998
1012 C. S. Potten and M. Loeffler
Mouse 2x1O8 cells shed/small intestine/dayMan «1011 cells shed/small intestine/day
1400cells/villus/day
300 cells/crypt/day/JM/J
VILLUS3500 cells 0
Tc»24h
(P) Paneth cells
2 x 108 cells shed per small intestine/day
1400 cells/villus per day
Calicivirus, Coronavirus, Astrovirus, enteroviruses, E. coli, Cryptosporidium, Rotavirus…polymicrobial problems
Parvovirus detection test?
Ag detection (fecal ELISA, aka SNAP)
Diarrhea panel (real time quantitative PCR)
CBC, Chemistry
Antimicrobials
Other supportive information
Spike gene mutations & host range
• FPV has not undergone significant changes in antigenic and biological properties since 1920
• CPV has undergone significant changes (1978): CPV-2a, CPV-2b, CPV-2c
• Host range determinant: spike gene (VP2)
• 6 AA changes differentiate FPV from CPV (80, 93, 103, 323, 564, and 568)
• 5 AA changes differentiate 2a, b and c from CPV-2 (87, 300, 305, 426, and 555)
• Host range determinants: AA 93, 375, and 426
1.Do newly recognized parvovirus strains have differences in virulence?
• Glu-426 mutation (VP2) = 2c Parvovirus
• Widespread in Europe (2000) and US
• Vaccine susceptible
• Ag test valid
CPV 2C
Reconsidering dogma: What is virulence?
Decaro N, Desario C, Addie DD, Martella V, Vieira MJ, Elia G, et al.Molecular epidemiology of canine parvovirus, Europe. Emerg Infect Dis 2007 Aug.
Case Breed Age Type
1 Min pin 2c
2 pit 6 mo CPV310
3 chihuahua 3 mo 2c
4 pit 2 mo 2c
5 chihuahua 6 mo
6 mix 8mo CPV310
7 shepherd <2 mo 2c
8 maltese 6 mo
9 pit 6 mo 2c
10 pit 4 mo 2c
11 pit X 6 mo 2c
12 X 6 mo 2c
13 X 3 mo 2c
14 pitpit 4 mo 2c
15 adult 2c
16 2c
17 2a
Dr. Jyothi Robertson, Koret Shelter Medicine Service
CPV$2c$in$California:
Mechanisms for rapid occupation by 2c Parvovirus
•higher virulence
more severe? susceptibility in adults? vaccine resistance?
• lower virulence?
shedding can be 1010-1012 per gram feces In a day 2 x 1019 single dose is 105 viruses
Endemic(pathogens(of(higher(or#lower#virulence(might(be(successful.
The cat-dog shuffle
Cross-Species Transmission of Canine Parvovirus 2 to
Healthy Shelter Kittens and Cats with Feline
Panleukopenia Syndrome
Christian Leutenegger, DrMedVet, PhD, IDEXX Laboratories, Inc., Sacramento, CA Hongwei Liu, MS, Niels C. Pedersen, DVM, PhD Center for Companion Animal Health, University of California, Davis, CA;
2. Do CPV strains cause disease in privately owned US cats?
3. Can we identify CPV strains in asymptomatic US shelter cats?
4. Does FPV expand its host range and infect US dogs?
FPV vs CPV Assay in Infected Cats
Cats can be infected with CPV (2b, 2c) or FPV (CPV-like mutation) Cases: sick cats with clinical diarrhea
#Cust
CountryShelter
FlagPanel Material Num Desc
Universal Parvo PCR Result*
FPV CPV Call
1 JP N FELINE DIARRHEA PANEL COMP 8.59 3.402 3.248 FPV / CPV
2 US N FELINE DIARRHEA PANEL COMP 22.92 2.746 8.631 CPV
3 US N FELINE DIARRHEA PANEL COMP 7.18 9.826 1.361 FPV
4 JP N FELINE DIARRHEA PANEL COMP 27.19 7.59 1.06 FPV
5 JP N FELINE DIARRHEA PANEL COMP 8.93 10.418 1.376 FPV
6 MX N FELINE DIARRHEA PANEL COMP 6.85 10.292 1.321 FPV
7 US N FELINE DIARRHEA PANEL COMP 11.13 11.888 1.532 FPV
8 US N FELINE DIARRHEA PANEL COMP 29.67 1.648 0.8 FPV
9 KR N FELINE DIARRHEA PANEL COMP 7.4 9.364 1.015 FPV
10 JP N FELINE DIARRHEA PANEL COMP 6.82 10.755 1.324 FPV
11 US Y FELINE DIARRHEA PANEL COMP 26.21 8.277 1.044 FPV
12 US N DIARRHEA PCR COMP PLUS FE 27.84 2.323 2.084 FPV
13 JP N FELINE DIARRHEA PANEL COMP 7.68 7.829 1.068 FPV
14 US N FELINE DIARRHEA PANEL COMP 25.05 2.587 7.72 CPV
15 JP N FELINE DIARRHEA PANEL COMP 5 10.229 1.422 FPV
16 KR N FELINE DIARRHEA PANEL COMP 20.22 2.578 2.446 FPV / CPV
17 JP N FELINE DIARRHEA PANEL COMP 7.59 10.371 1.307 FPV
18 US N FELINE DIARRHEA PANEL COMP 9.13 3.785 3.443 FPV / CPV
19 US N FELINE DIARRHEA PANEL COMP 9.66 10.065 1.259 FPV
20 JP N FELINE DIARRHEA PANEL COMP 15.42 9.388 0.959 FPV* CP Value (Cycle point)
FPV vs CPV
Privately owned cats, sick Clear identification of canine parvovirus infections!
Shelter kittens Clear identification of canine parvovirus 2a, b, and c CPV-2c cannot be explained by vaccine High Parvovirus load in sick and healthy kittens!
Privately owned dogs, sick No dog has been identified with FPV infection
Parvovirus Types in Shelter Kittens
367 fecal samples for Parvovirus typing (July ‘10, July ‘11, January ‘12)
• June 2010: 47 • June 2011: 217 • Janu 2012: 103
Two categories of parvovirus load Low viral load <1.2 million viral equivalents per gram of stool • Environmental contamination • Vaccine interference (MLV) • Carrier with no clinical manifestations High viral load >1.2 million viral equivalents per gram of stool • Normally associated with (some sort of) clinical signs • Highest viral load detected: 2.38 x 1012 (2.38 Trillion)
34
Dora the Labrador
A"watermold"story......
35
A"watermold"story......
help the individual animal
help the herd
identify emergence
identify zoonoses36
37
Rice, Golf, and Lawncare?
Canine Influenza• Two distinct strains of IAV have emerged in domestic
dogs, with each circulating widely for several years. • Clinical presentation in dogs
herd individual
• Diagnostics • Exposure (serology) and viremia (shedding and
circulation) • Natural history of influenza, myths and predictability
Streptococcus, isolation in normal dogs
conjunctiva
oropharynx
skin
genital
urinary
gastrointestinal
When is isolation significant?
*From where is the isolate?
Co-pathogens?
Herd Health (Shelter perspective)
References: Chalker et al, 2003Kim et al, 2007Pesavento et al, 2008Byun et al 2009Britton et al, 2010
Canine Influenza Virus H3N8! Data range 2007 – April 2015
! CRD panel includes 11 infectious agents & 7 quality controls
! Frequency has declined over the past 4 years
! Chicago CIV H3N8 cluster detected in 2008, single positives in the past 6 years
! Other active clusters in Southern California, Texas and New York
45
Establishment"of"influenza"in"new"hosts
Parrish"et"al,"2015
H3N2 Influenza Virus
• Submissions across the US from March to May 2015 were re-tested with H3N2 real-time PCR in a retrospective study
• March: 949 swabs were tested of which 89 or 9.5% tested positive • April: 871 swabs were tested of which 173 or 19.9% were positive.
• Positive cases: (March 1st – May 5th):Alabama, n=2
California, n=1 Illinois, n=222 Indiana, n=2 Michigan, n=3 Minnesota, n=6 New Jersey, n=1 Texas, n=1 Virginia, n=1 Wisconsin, n=3
Data source: unpublished data, IDEXX Laboratories, Inc. Version 05 14 2015
Canine&Circo*,&Boca*,&and&Kobuviruses
Virus&:&Host&Interaction Pathogen&discovery
Kobuvirus Sapovirus Circovirus Bocavirus Amdovirus
Discovery*vs.*research*that*determines*causality*and*pathogenesis
Vasculitis?
Diarrhea
Normal"artery Case"1:arteriAs
Vasculitis,&histiocytic&disease
virus
DogCV2063 bp
RepCap
ORF3
PCV21768 bp
Rep
Cap
ORF3
FiCV StCV
RaCV CaCV CoCV
GuCV BFDV
SwCV GoCV
DuCV PCV1
PCV2 DogCV-UCD3 Blood
Canine CV isolate 214 DogCV-UCD2 Feces DogCV-UCD1 Tissue
Barbel CV CyCV NG13
Catfish CV CyCV TN25 CyCV PK5034 CyCV PK5006
CyCV NG chicken 8 CAV
100
6499
100
92100
99100
8970
8797
99
81
99
95
68
52
0.1
In*feces:
healthy&dogs:&&& & & & & & 14/204&& & & 6.9&% diarrheic&dogs&& & & & & & 19/168& & & 11.3&%&
& Thirteen&of&19&positives&dogs&(68%)&were&co*infected&with&one&or&multiple&& other&pathogens,&including&Canine&Enteric&Coronavirus,&Cryptosporidium& & spp.&,&C.&perfringens&alpha&toxin,&Giardia&spp.,&Salmonella&spp.,&Campylobacter&& jejuni,&and&Campylobacter&coli
In*blood:
Dogs&with&thrombocytopenia& & 16/480&& & & 3.3% or&neutropenia& (similar&to&that&reported&previously&in&canine&serum&samples&(2.9%,&6/205)
One*amplicon*from*blood*samples*had*>10%*nucleotide*distance*to*DogCVAUCD1&2.&
Frequency&of&dogCV&detected&by&real&time&PCR
Frequency&of&dogCV&detected&by&real&time&PCR
Frequency&of&dogCV&detected&by&serology?
B e r n i c e B a r b o u r F o u n d a t i o n