FMD Ecology: Collaborative

Studies

Anna Ludi, Zaheer Ahmed, Steve Pauszek,

Jonathan Arzt and Luis L. Rodriguez

Plum Island Animal Disease Center

Disease Ecology

• Differs from a traditional medical approach

in that it’s not concerned with describing

the pathology of individuals

• Differs from epidemiology in that the

emphasis is on general processes of host

population, environment and agent

interactions – long term maintenance

Epidemiology vs Ecology?

• Epidemiology: the study of the determinants of disease

and injuries

– What causes disease? Where and When?

– Mechanistic

• Disease ecology: the study of the underlying principles

that influence the spatio-temporal patterns of disease

– Adds the Why to the equation, (e.g. why do patterns of disease

occur as they do?)

– Conceptual: what variables play roles on disease

Pathogenesis

Route of entry

Dissemination

Genetic background

Genetic determinants of virulence

Patterns of EvolutionClimate change

Environmental disruptions

FMD Ecology

• Epidemiological knowledge on FMD

clinical occurrence is large• Geographic distribution (pools) of serotypes/

topotypes derived primarily from clinical

occurrence

• Little known about FMD ecology:

– Where is FMD between outbreaks?

– Role of persistence (e.g Asian buffalo) in long

term maintenance?

– What determines emergence of epidemic

viral strains?

Objectives• 1. To better understand the ecology of FMDV circulating in selected

endemic regions of Asia and Africa

• 1.1 Acute Clinical Samples: conduct systematic FMD monitoring program to

determine the molecular epidemiology of FMDV in local livestock

• 1.2 Collect samples from subclinical and persistently infected animals

(longitudinal field study)

• 1.3 Understand role of Asian buffalo on FMD transmission

• 2. To determine the phylogenetic relationships of FMDV strains in endemic

regions

• 3. To determine the antigenic relationship (vaccine matching) of FMDV

strains circulating in the selected regions with currently available vaccine

strains

• 3.1 Establish panel of reference cattle sera for vaccine matching testing

• 3.2 Measure antigenic relationship of field FMDV strains with reference

vaccine sera

PAKISTAN

CHARACTERIZATION OF LOCAL ISOLATES OF FMDV AND

DEVELOPMENT OF VECTOR BASED VACCINES

58-1940-7-161F; 057 002S

9/1/2007 - 8/31/2012

REAL TIME DATA ANALYSIS AND RESEARCH CAPACITY

BUILDING TOWARDS FMD CONTROL IN PAKISTAN

1940-32000-052-14S

09/27/20 12 - 09/27/2014

Dr. Khalid Naeem – NARC

Dr. Umer Farooq – NARC

Dr. Muhammadimam Afzal, FAO

Dr. Manzoor Hussain, NVL

Objectives

• In collaboration with the Center for Animal Disease Modeling Systems at UC Davis carry out genomic evaluation of field isolates using BioPortal

• Vaccine matching using sera derived from:– Trivalent Merial and ARRIAH vaccine

– Cattle and buffaloes

– Days 0, 7, 14, 28, 60 and 90

• Persistence studies in cattle and buffaloes in a natural setting– Sample collection at farms in high risk areas

• Anatomical pathology of persistence of FMDV in cattle and buffaloes– FMDV positive cases will be slaughtered and samples of Naso-pharynx, top

of pharynx, dorsal of palate, regional lymph nodes and tonsils will be taken

Accomplishments

TASK 1.1 – Acute Clinical Samples

• 42 P1 FMDV sequences have been obtained

• 85 samples currently in the process of being shipped

TASK 1.2 – Longitudinal Field Study

• 4th rounds of sampling currently taking place of NSP positive animals

• Initially 300 samples were collected with 233 being positive for NSP

• NSP-ELISA, RT-PCR and virus isolation is currently being undertaken in Pakistan

TASK 3.1 – Establish panel of reference sera for vaccine matching testing

• 144 sera samples collected:– against both Merial and ARRIAH vaccine

– Cattle and buffaloes

– Sera collected days 7, 14, 28, 60 and 90

OTHER ACCOMPLISHMENTS -

• Training session in Pakistan to teach epidemiology, bio-portal, cell culture and virus isolation

# of samples Year Region Species Serotype

3 2008 ICT Cattle A

5 2009 Sindh Cattle & Buffaloes A & O

10 2010 Punjab Cattle & Buffaloes O

12 2011 Punjab Cattle O & Asia 1

12 2011 Sindh Buffaloes Asia 1, O or mixed infection

Significant amino acid and nucleotide variations were

associated with spatial distance, but not with differences

in host species, consistent with the frequent multispecies

infection of this serotype O FMDV.

Future Planned Work

• Continued collaboration with UC Davis to utilize BioPortal to map all outbreaks detected

• Carry out vaccine matching with serotype O, A and Asia 1 to answer following questions:

• Is there a difference between neutralization titers obtained amongst cattle and buffaloes?

• What is the neutralization responds of animals having maternal antibodies?

• How are neutralization values affected by using trivalent vaccines (comparison will be made in collaboration with IAH, WRL)

• If funding allows in vivo testing of results (ie vaccine challenge studies)

• Characterization of persistent virus and phylogenetic comparison with strains causing outbreaks in the same regions

VIETNAMMOLECULAR EPIDEMIOLOGY, SURVEILLANCE AND

PREDICTIVE TOOLS FOR FMD CONTROL IN VIETNAM

58-1940-0-070F, 057 14S

6/1/2010-9/30/2012

Dr. Thanh Long Ngo, DAH,

HCMC

Dr. Ho Huu Dung, DAH, Hanoi

Dr. Carla Huston, Mississippi

State University

Objectives

• Molecular epidemiology of FMDV in local livestock including

cattle, buffaloes and pigs

• To better understand the transmission mechanism of

persistently infected to susceptible livestock in natural setting

• Enhance strategies for identification of persistently infected

animals using new technology

• Vaccine matching to asses efficacy against currently circulating

strains.

AccomplishmentsTASK 1.1 – Acute Clinical Samples

• Received 69 samples:

– Samples collected during outbreak

– Pigs, buffaloes and cattle

– Northern and Southern Vietnam

• Preliminary sequencing from 43 samples identifies serotypes A and O

TASK 1.2 – Longitudinal Field Study

• HCMC region – finished collecting samples for the third time; probang after second sampling indicated 11 positive animals on 9 farms

• Hanoi-SonLa region – third round of sampling now taking place; 9 carrier cattle and 5 carrier buffalo have been identified

TASK 3.1 – Vaccine Matching Testing

• Possibility of obtaining monovalent serotype O sera

Other Accomplishments

• Trained Saigon and Hanoi veterinarians in theoretical and practical aspects of probang sampling

Future Planned Work

• Dr. Jonathan Arzt to visit before the end of the year

18 persistent buffalos identified for necropsy and detailed

tissue distribution analysis

CAMEROONTRANSMISSION AND EVOLUTION STUDIES OF FMDV IN

LIVESTOCK IN THE LAKE CHAD BASIN58-1940-0-047N, 05713 – Non-Funded

04/01/2010 to 04/30/2015

Dr. Rebecca Garabed, Ohio

State University

Dr. Simon Dickmu, LANAVET

Objective

• To understand the epidemiology of infectious diseases in the

ecological context of networks of host movement

• How different networks of livestock movement affect disease

epidemiology

Accomplishments

TASK 1.1 – Acute Clinical Samples

• Sequencing has shown serotypes O and SAT 2

– Currently in the process of obtaining full P1 sequences on 12 samples

– Another 76 rRT-PCR positive samples to be processed

TASK 1.2 – Longitudinal Field Study

• 385 serum samples have been analyzed using virus

neutralization -Serotypes O, A and SAT2

Other Accomplishments

• In the process of writing manuscript

Accomplishments

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Cattle infected with numerous serotypes

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FMDV serotypes prevalent in Cameroon from 2010-2012

Serotype O

Serotype A

Serotype SAT1

Serotype SAT2

Serotype SAT3

SAT 2 incursion into Northern Africa?

Outcomes

• What new project ideas have been created?

– Multiple FMDV serotypes co-infecting same animals,

what is the mechanism? How many viruses co-exist

in same animal?

– FMDV strains SAT2 serotype detected in Cameroon

2010-2011, is this the SAT2 that incursioned into

north Africa?

Future Planned Work

UNDERSTANDING THE ECOLOGY OF

FOOT-AND-MOUTH DISEASE VIRUSES

CIRCULATING IN CAMEROON Not yet established - 057 42S

06/01/12-05/31/14 (pending signatures)