1. Foot-and-Mouth Disease
Notes by Onyango Ngoye

2. Foot-and-mouth Disease
Contents
Definition
Host range
Incubation
Clinical signs
Transmission
Diagnosis
Control
Foot-and-Mouth Disease

3. Foot-and-Mouth Disease
Definition
Foot-and-mouth disease is a highly contagious, viral disease of domestic cloven-hoofed and many wild animals characterized by erosions in the mucosa of the mouth and hooves.
Image courtesy of Dr Tom McKenna
Foot-and-Mouth Disease

4. Foot-and-Mouth Disease
Cont.
This devastating disease is considered to be the most important livestock disease in the world.
It is The most contagious viral disease of animals.
Foot-and-Mouth Disease

5. Important factors about FMD
Short incubation period
Release of virus prior to appearance of clinical signs
Massive quantities of virus released
Foot-and-Mouth Disease

6. Foot-and-Mouth Disease
Extended survival in the environment
Multitude of routes of virus transmission
Minimal size of the infective dose
Aerosol transmission possible up to 250 km depending on strain and environmental conditions (10km, 170km, 250km reported over water)
William White, PIADC
Foot-and-Mouth Disease

7. Foot-and-Mouth Disease cont.
Although not very lethal to adult animals, it causes serious production losses.
Image 1 provided by Dr Corrie Brown, Image 2 provided by Dr Tom McKenna
World cow image taken from Internet at:
FMD is a major constraint to international trade in livestock and livestock products
Foot-and-Mouth Disease

8. Foot-and-Mouth Disease
Host Range
Most cloven-footed wild animals:
Deer
Antelope
Hogs
Wild hog image from Texas Animal Health Commission with thanks to Dr Ken Waldrup
Foot-and-Mouth Disease

9. Foot-and-Mouth Disease
Host Range cont.
Water buffalo
can be carriers for
5 years.
Image courtesy of Dr Linda Logan
African water buffalo
Foot-and-Mouth Disease

10. Foot-and-Mouth Disease
Host Range cont.
Giraffes
Elephants
Images by Linda Logan and Tita Burnham
Foot-and-Mouth Disease

11. Foot-and-Mouth Disease
Host Range cont.
Hedgehogs,
Rats,
Mice,
Guinea pigs.
Hedgehogs can become infected with FMD virus, and can transmit the disease to other hedgehogs.
Foot-and-Mouth Disease

12. Foot-and-Mouth Disease
Host Range cont.
Not seen in odd-toed
animals such as
horses, zebras or rhinos
Horse image from:
Rhino image from:
Foot-and-Mouth Disease

13. Foot-and-Mouth Disease
Image by Dr Linda Logan, Cairo Jan. 2006
Old World Camel
is resistant to
natural infection
Foot-and-Mouth Disease

14. Foot-and-Mouth Disease
Incubation
Incubation period depends on which strain of FMD virus (7 serotypes), dosage,
and the route of entry.
As short as 2-3 days in close contact
As long as days from windborne infection
Experimentally shown to be as short as hours
Foot-and-Mouth Disease

15. Foot-and-Mouth Disease
Pathogenesis
Most animals acquire virus usually by inhalation
Pigs are more susceptible to infection by oral route
Foot-and-Mouth Disease

16. Foot-and-Mouth Disease
Image from the Pig: from the “Pig Site.com” and
Foot-and-mouth blisters on a pig's snout
Foot-and-Mouth Disease

17. Foot-and-Mouth Disease
24 hrs after infection, virus begins replicating
Virus is excreted in high quantities in air expelled from lungs, in all secretions including milk, and ruptured vesicles.
Pigs can excrete up to 400 million infective virus particles a day
“Virus is excreted in high quantities in expired air, in all secretions and excretions (including milk and semen), and from ruptured vesicles. Pigs liberate vast quantities of airborne virus in their expired breath. An infected pig can excrete up to 400 million TCID50 a day, but ruminant animals excrete a maximum of only 120,000 TCID50 a day.” Geering, W.A., A.J. Forman and M.J. Nunn, Exotic Diseases of Animals, 1995; Canberra, Australian Government Publishing Service, p.115.
Foot-and-Mouth Disease

18. Foot-and-Mouth Disease
Pathogenesis
Virus replication in respiratory epithelium and lymphoid tissue
In domestic ruminants pharynx and dorsal soft palate are predilection site for replication of FMDv
Virus persists there for prolonged periods
Thomson, G. R. and Bastos, A. D. S. “Foot-and-mouth disease” Ch 125 of Infectious Diseases of Livestock, Volume 2. Ed. J. A. W. Coetzer and R. C. Tustin. Oxford University Press, second edition, 2004,
Foot-and-Mouth Disease

19. Foot-and-Mouth Disease
Replication in lymphoid tissue, tonsils mucosa of soft palate
Virus can be recovered from retropharyngeal, mandibular, and parotid lymph nodes in more than 50% of cattle in pre-viremic stage
Thomson, G. R. and Bastos, A. D. S. “Foot-and-mouth disease” Ch 125 of Infectious Diseases of Livestock, Volume 2. Ed. J. A. W. Coetzer and R. C. Tustin. Oxford University Press, second edition, 2004,
Foot-and-Mouth Disease

20. Foot-and-Mouth Disease
High virus levels may occur in organs and tissues which do not generally develop gross changes including unaffected skin areas
Thomson, G. R. and Bastos, A. D. S. “Foot-and-mouth disease” Ch 125 of Infectious Diseases of Livestock, Volume 2. Ed. J. A. W. Coetzer and R. C. Tustin. Oxford University Press, second edition, 2004,
Foot-and-Mouth Disease

21. Predilection of blisters (Major sign)
The mouth, feet and teats are predilections sites for blisters in cattle;
The dorsum of the snout in pigs.
The knees in warthogs.
Thomson, G. R. and Bastos, A. D. S. “Foot-and-mouth disease” Ch 125 of Infectious Diseases of Livestock, Volume 2. Ed. J. A. W. Coetzer and R. C. Tustin. Oxford University Press, second edition, 2004,
Foot-and-Mouth Disease

22. Clinical Signs of Foot-and-mouth Disease:
Host range
Incubation
Clinical signs
Transmission
Diagnosis
Control
Foot-and-Mouth Disease

23. General Clinical Signs
Images from the USDA Image Library
Foot-and-Mouth Disease

24. General Clinical Signs
Vesicles and erosions in the mucosa of the mouth, and skin-hoof junction
Excessive salivation
Lameness
Foot-and-Mouth Disease

25. General Clinical Signs
Listless
Lifting feet alternately
Lameness
Clear nasal discharge progressing to mucopurulent
Image from USDA image library
Foot-and-Mouth Disease

26. General Clinical Signs
Blisters in the mouth
Blisters on the muzzle
Blisters on the tongue
Excessive Salivation
Image from USDA image library
Foot-and-Mouth Disease

27. Foot-and-Mouth Disease
Exessive salivation
Foot-and-Mouth Disease

28. Foot-and-Mouth Disease
Signs develop rapidly in cattle and are more severe than lesions in pigs, sheep or goats.
If all species are exposed together, cattle will show signs first.
Some serotypes of FMDV affect particular species more than others.
Foot-and-Mouth Disease

29. Clinical Signs in Cattle
Fever (103°-106°F)
Depression
Anorexia
Milk production ceases
Blisters start to form in the mouth
Excessive ropy, viscous salivation
Blisters rupture within 24 hrs leaving raw, painful ulcers
Mouth lesions usually heal in days
Foot-and-Mouth Disease

30. Clinical Signs in Cattle
Blisters form on:
Mouth
Tongue
Dental pad
Gums
Soft palate
Muzzle
Nostrils
Feet
Inter-digital space
Coronary band
Teats
Foot-and-Mouth Disease

31. Image courtesy of Dr Tom McKenna
Blister in the tongue

32. Images courtesy of Dr Tom McKenna
Blisters in the Muzzle

33. Blisters in the Gum and dental pad
Images courtesy of Dr Tom McKenna
Blisters in the Gum and dental pad

34. Blisters in the inter-digital space and coronary band.
usda
Blisters in the inter-digital space and coronary band.

35. Clinical Signs in Cattle
Body tremors from pain
Lameness from developing lesions on feet
Foot-and-Mouth Disease

36. Clinical Signs in Cattle
Lameness
Coronary band lesion
first appears blanched
Blisters form between
the digits
Stamping and shaking
of feet
Trembling
Excretion of virus from foot lesions tends to last a day or two longer than from mouth lesions, so foot lesions may be a better source of virus for diagnostic purposes in older cases. Geering
Foot-and-Mouth Disease

37. Clinical Signs in Cattle
Smacking of the lips and sucking of the sore tongue is characteristic
Secondary Bacterial infections
Mastitis –permanent damage to udder
Pregnant cows may abort
Copious salivation in an acutely affected Balinese cow, (P.T Hooper) from Geering, p. 119.
Foot-and-Mouth Disease

38. Progression of disease
Blisters at infection site initially appear as blanched area in the epithelium
Area fills with serous fluid forming a vesicle
Vesicles enlarge and coalesce
Vesicles crack or rupture leaking fluid
The epithelium necroses off leaving raw ulcer or erosion
Foot-and-Mouth Disease

39. Progression of disease
Grey fibrinous coating forms over lesions
The coating becomes discolored, yellow, brown, green
As epithelium is restored, lines of demarcation are evident
Sometimes but not always, permanent scars form
Foot-and-Mouth Disease

40. Progression of disease
When blisters are present, cattle salivate profusely with ropy viscous material hanging from mouth
Also see severe lacrimation and nasal discharge
When vesicles rupture, fever ends followed by end of viremia
Start to finish, signs last days.
Foot-and-Mouth Disease

41. Progression of disease
Recovered animals are permanently unthrifty
Image by Dr Suzanne Burnham
Foot-and-Mouth Disease

42. Aging lesions in cattle
Day One
Formation of fluid-filled blister, or vesicle
2 mm-10 cm on the dorsal surface of the tongue
Foot-and-Mouth Disease

43. Aging lesions in cattle
Day
Six
Day
Four
Salivation increases as vesicles form and
rupture. Symptoms increase in intensity.
Foot-and-Mouth Disease

44. Aging lesions in cattle
Days 8-14
Animals may recover in
2 weeks. Only 1-5%
die from FMD
High morbidity,
Low mortality
Lines of demarcation
Foot-and-Mouth Disease

45. Clinical Signs in Cattle
Morbidity approaches 100% in a susceptible herd.
Merck
FMD – Brazil, Argentina, Uruguay. 2000
Foot-and-Mouth Disease

46. Clinical Signs in Cattle
Low Mortality
Rarely fatal except in young animals
Extra-epithelial
replication limited to
myocardium,
immature animals only
USDA
USDA
Foot-and-Mouth Disease

47. Clinical Signs in Cattle
Young calves may die without showing any clinical signs
Images taken by S Burnham
Foot-and-Mouth Disease

48. Foot-and-Mouth Disease
In young animals there is focal necrosis
of cardiac muscle. “Tiger heart”
50-80% young animals die (calves, lambs, etc)
Image provided Drs Linda Logan and Tom McKenna
by Dr Linda Logan
USDA
USDA
Foot-and-Mouth Disease

49. Foot-and-Mouth Disease
Recovery
Recovered animals are have poor body condition
Image by Dr Linda Logan
Foot-and-Mouth Disease

50. Foot-and-Mouth Disease
Recovery
More than 200 cattle have been sickened with foot-and-mouth disease since June but now all the cattle have recovered and it has not spread," said Keo Rithy, deputy chief of Kampong Chhnang's animal health and production office.
Cattle in three villages in Kampong Chhnang province had been infected but none had died and no cullings were carried out, he told AFP.
Foot-and-mouth disease is a severe, highly contagious viral disease that affects all species of cloven-hoofed animals but is not usually fatal in fully grown animals.
Financial losses as a result of the disease can be significant both in direct losses due to deaths in young animals, loss of milk, loss of meat and a decrease in productive performance.
Cambodian farmers depend heavily on cows and buffaloes for their livelihoods. — AFP
More than 200 cattle in Cambodia have been infected with foot-and-mouth disease since an outbreak last month northwest of the capital but have since recovered, an animal health official said.
"More than 200 cattle have been sickened with foot-and-mouth disease since June but now all the cattle have recovered and it has not spread," said Keo Rithy, deputy chief of Kampong Chhnang's animal health and production office.
Majority of infected cattle recover.
Foot-and-Mouth Disease

51. Foot-and-Mouth Disease
Up to 50% of recovered
ruminants continue
to shed the virus sporadically,
6-24 months post-infection.
Images by Dr Suzanne Burnham
Foot-and-Mouth Disease

52. Foot-and-Mouth Disease
Water buffalo can be carriers for 5 years
Photo by Dr Linda Logan
Foot-and-Mouth Disease

53. Clinical Signs in Swine
Fever
No appetite
Reluctant to move
Worst blistering is on the feet
May slough the hoof
Abortion
Suckling piglets die suddenly – even before blisters develop
USDA
Foot-and-Mouth Disease

54. Blisters on the snout of a pig.
Tom McKenna
Blisters on the snout of a pig.

55. Blisters on the feet of a pig
Tom McKenna
Blisters on the feet of a pig

56. Clinical Signs in Swine
USDA
Blisters on teats and udders
Mastitis
Foot-and-Mouth Disease

57. Pigs & Swine reluctant to move
USDA
Painful feet.
Foot-and-Mouth Disease

58. Tom McKenna
Painful feet

59. Clinical Signs in Sheep and Goats
USDA
Vesicles on dental pad and between toes
Prone to develop secondary foot-rot
Lamb death, 50-90%
Sheep can be carriers for up to 9 months
Foot-and-Mouth Disease

60. Image courtesy of Dr Tom McKenna
Blisters in goats

61. Foot-and-Mouth Disease
Image courtesy of Dr Tom McKenna
Foot-and-Mouth Disease

62. Clinical Signs in Sheep and Goats
When sheep or goats become infected with FMD, the disease may not be diagnosed for a considerable time because the clinical signs may be very mild.
Foot-and-Mouth Disease

63. Foot-and-Mouth Disease
Sheep may appear healthy but will be producing infectious aerosols or spreading the virus via urine, feces or direct contact.
Image by Dr Kenneth Waldrup
Foot-and-Mouth Disease

64. Foot-and-Mouth Disease
Lesions in giraffe
Image from presentation on FMD by Moritz van Vuuren at 2005 FEAD course in Tennessee
Foot-and-Mouth Disease

65. Foot-and-mouth Disease:
Host range
Incubation
Clinical signs
Transmission
Diagnosis
Control
Foot-and-Mouth Disease

66. Foot-and-Mouth Disease
Transmission
Aerosols/Airborne, Inhaled
Direct or indirect contact-droplets,
Ingestion
Artificial Insemination
Vectors (vehicles, equipment, or humans)
Carrier state
Foot-and-Mouth Disease

67. Foot-and-Mouth Disease
Transmission
Aerosol
Spread of aerosols from infected animals, given the right temperature and humidity can travel 250km on the wind
Aerosols transmission via dust storms in Africa spread FMD to England
Dr tom McKenna
Foot-and-Mouth Disease

68. Foot-and-Mouth Disease
Transmission
Airborne on the wind
Airborne from burning pyres suspected
Airborne from infected milk transport
Image by Dr Kenneth Waldrup
Foot-and-Mouth Disease

69. Foot-and-Mouth Disease
Transmission
Aerosol droplets spread from infected animal
Sheds 400,000,000 virus
particles per day
Only takes 10-12
virus particles to
infect one cow
Foot-and-Mouth Disease

70. Foot-and-Mouth Disease
Transmission
Direct or indirect contact with infected animals
Feral hog image from Texas Animal Health Commission, permission by Dr Ken Waldrup
“World cow” from Internet
If infected feral hogs come into contact with domestic
livestock in the US, it will affect the whole world!
Foot-and-Mouth Disease

71. Foot-and-Mouth Disease
Transmission
Foot and mouth disease
virus can be transmitted
via:
Milk
Semen
Saliva
Feces
Urine
Breath
Foot and mouth disease virus can be transmitted from incubating or clinically affected animals
via: milk, semen, saliva, feces, urine, breath
“Supersoaker fights on the dairy farm”
Foot-and-Mouth Disease

72. Foot-and-Mouth Disease
Transmission
Ingestion- Feeding contaminated garbage (meat, milk, glands, bones, cheese, etc)
Intraocular
Artificial insemination, or natural reproduction
Foot-and-mouth disease can be introduced into a free area in many ways. Airborne droplets with FMD virus is probably the most natural means of infection, but the virus can be transmitted many ways. FMD can be transmitted through the eye. (Sutmoller, P. and McVicar, J.W., “Foot-and-mouth Disease: Early virus growth after conjunctival exposure of cattle”. Archiv. Fur Gesamte Virusforschung, as reported by
Callis, J.J., “Foot-and-mouth Disease in Cattle – Some Relationships Between Pathogenesis and Epizootiology”. Foreign Animal Diseases Seminar, Proceedings. March 15-16, 1980, University of Missouri, CVM with USDA, APHIS, VS, Emergency Programs, PIADC. P.1-10.
Foot-and-Mouth Disease

73. Foot-and-Mouth Disease
Vectors
Contact with contaminated objects (equipment, footwear, clothing)
Foot-and-Mouth Disease

74. Transmission by humans
A person in contact with infected animals may retain and exhale virus for up to 36 hours and serve as source of infection.
Humans serve as a mechanical vector when moving from infected animals to susceptible animals.
Amass, S.F., J.M. Pacheco, P.W. Mason, J.L. Schneider, R.M. Alvarez, L.K. Clark, and D. Ragland, “Procedures for preventing the transmission of foot-and-mouth disease virus to pigs and sheep by personnel in contact with infected pigs”. Veterinary Record, 2003; 153,
Amass, S. F., P. W. Mason, J. M. Pacheco, C. A. Miller, A. Ramirez, L. K. Clark, D. Ragland, J. L. Schneider, and S. J. Kenyon, “Procedures for preventing transmission of foot-and-mouth disease virus (O/TAW/97) by people”. Veterinary Microbiology 2004; 103:143-9.
Hyslop, N.S. “Transmission of the virus of FMD between animals and man”. Bulletin of the World Health Organization, 1973; 49:
Sellers, R.F., Donaldson, A.I., Herniman, K.A., “Inhalation, persistence and dispersal of foot-and-mouth disease virus by man. J. Hyg. (Lond)1970; 68,
Sellers RF, Donaldson AI, Herniman KAJ, “Transfer of foot and mouth disease virus by man”, Vet Record 1971; 68:
Foot-and-Mouth Disease

75. Foot-and-Mouth Disease
Transmission
Birds can be mechanical vectors and can pass viable FMD virus after ingestion, but are not considered a factor in the spread of the disease
Donaldson, A. I., “Quantitative data on air-borne foot-and-mouth disease virus. Philosophic Transactions of the Royal Society of London, B, 302: , 1983.
Hurst, G.W. “foot –and-Mouth disease: the possibility of continental sources of the virus in England in epidemics in Oct and several other years” Veterinary Record 81: 610-4, 1968.
Foot-and-Mouth Disease

76. Foot-and-Mouth Disease
Birds can also be infected with
FMD virus and shed virus in feces
Foot-and-Mouth Disease

77. Foot-and-Mouth Disease
Intentional act of
Bioterrorism
Courtesy Maryland Dept of Agriculture Public Affairs
Effective if humidity is
>60%
Can travel 60km overland
or 300km over water
images/nzcropduster.jpg
Foot-and-Mouth Disease

78. Foot-and-mouth Disease:
Etiology
Host range
Incubation
Clinical signs
Transmission
Diagnosis
Differential Diagnosis
Foot-and-Mouth Disease

79. Foot-and-Mouth Disease
Diagnosis
Clear clinical signs
Serum neutralization test
Complement fixation test
Enzyme-linked immunosorbent assay
FAO
Field diagnosis
Foot-and-Mouth Disease