Several parasitic infections and infestation are common in developing countries where companion animals (dog and cats) play an important role. The presentations talks about a few important ones .
Hemostasis Physiology and Clinical correlations by Dr Faiza.pdf
Â
Role of companion animals in emergence and transmission of Parasitic Zoonoses
1. Role of Companion Animals in
emergence and transmission of
Parasitic Zoonoses
Dr. M. Senthil Murugan, M.V.Sc Scholar Epidemiology
Dr. D.K. Singh, Principal Scientist, Veterinary Public Health
Dr. Bhoj R Singh, Principal Scientist and Head, Division of Epidemiology
2. Companion animals?
• An animal that someone keeps for company and
enjoyment
(MacMillan dictionary)
• Dogs, Cats, rodents, birds, Fish and horses
3. Companion versus Stray dogs
As Pets
• Human – Animal bond
• Mental ,Physical and Social
well being
• Utility, sporting, assistance
dogs – Blind & deaf
MacPherson et al., 2010
Stray Populations
• Developing Countries – High
Stray dogs population
• Share close relationship
with humans
• In India 19 million Stray dogs
Traub, et al., 2005
4. Who are at risk ?
Those in need of companion and---.
1. Immuno Compromised individuals- AIDS,
Cancer, Organ and Bone marrow transplants,
Steroid therapy
2. Children, Geriatrics
3. Pregnant Women
4. Veterinary professionals
5. Animal handler / Researcher
Robertson et al., 2000
5. Parasitic Zoonotic
Agent
Disease in Humans
Echinococosis
Ecchinococcous granuloses
Echinococcus multilocularis
Cystic echinococcosis
Alveolar echinococcosis
Toxoplasmosis
Toxoplasma gondii
Congenital and Ocular
Toxoplasmosis
Toxacariasis
Toxacara canis,
Toxacara cati
Visceral and Ocular Larval
Migrans
Ancylostomiasis
Ancylostoma caninum
A.ceylanicum
Cutaneous Larval Migrans
Giardiasis
Giardia duodenalis
GI disturbances
Cryptosporidiosis
Cryptosporidum canis,
C.felis
Rare infection
Leishmaniasis
Leishmania donovani
Cutaneous and Visceral
Leishmaniasis
Dipylidiasis
Dipyllidium caninum
Disease in Companion
animals
Children are affected
6. Human behavior and emergence of
parasitic zoonoses
• Growing global population (>6.4 billion) causing:
1.
Exploitation of natural environment, e.g. AE
2.
Urbanization – Inadequate sanitation and garbage disposal.
3.
High percapita garbage – more stray dogs.
4.
Breeding sites for vectors e.g. Leishmaniasis in dogs.
5.
Inappropriate feeding: Uncooked meat (Smoked & cured) e.g.
Toxaplasma cysts. Feeding offals to dogs may lead to
Echinoccosis.
6.
Poor hygiene – Lower economic strata, so many faeco-oral
infections.
Macpherson, 2005
7. Dogs as Mechanical Carriers
• Mechanical reservoir for human parasites
• Host specific human parasites – Ascaris
lumbricoides, Trichuris trichiura, Hymenolepis
diminuta and Isospora belli
• Viable Ascarid eggs isolated from 30 % of dog
feces in Assam (Traub et al., 2005)
• Fur of dogs – Carry T. gondii to humans
(Tenter et al., 2000)
8. Factors for Emergence of GI Protozoans
• Western world & Urbanization –
regular deworming of pets
• Enteric protozoans remains
unaffected by anthelminthics
• Intestinal protozoans (Giardia
and Cryptosporidium) may be
colonizing the niche vacated by
T. canis and D. caninum and
other helminths killed by
anthelmintics.
• Pet ownership
Robertson et al., 2000
Giardia colonization of GI mucosa
9. Transmission of Giardiasis
• Giardia duodenalis - Humans are reservoir
• Zoonotic strains of Assemblage AI, AII and B – from
dogs
• Cysts – infective stage, prolonged survival of cysts in
environment (Weeks to months)
• Ingestion of food, water or arthropods carrying cysts.
• 10 – 100 cysts sufficient for Direct fecal - oral and water
borne transmission
Thurtson et al., 2002
10. Emergence Giardiasis in Assam
• Type A 39 % & B 61% in humans
• Same Genotype in the same village and the same
house hold both in Dogs & Humans
• Human isolates - Assemblage A or B and that all found in
Dog isolates
• Dog was infected through Coprophagy of human feaces
• Multi-dog in household are more prone for infection
• Dogs infected with own host adapted Assemblage C &
D, and also with Zoonotic genotypes A and B
Traub et al., 2004
11. Minimal zoonotic risk & Cryptosporidiosis
• C. canis and C. felis oocysts are
common in feces dogs and Cats
• Human cases are associated with
C. hominis and C. parvum
• Molecular epidemiologic studies
proves low risk of zoonotic
transmission
• Rarely immunocompromised pet
owners may acquire the infection
from dogs.
Forster et al., 2010
Lifecycle of Cryptosporidium sp
12. Transmission of Toxoplasmosis
• Toxoplasma gondii from Cats
• Highly resistant oocytes
• Asexual stages in intermediate
host (IMH) – all vertebrates
• In Pregnancy – Vertical
transmission
• Cats excrete oocysts for 20
days of infection
• Reinfection infection after 6
yrs, however under
immunosupression cats starts
to excrete oocysts
Tenter et al., 2000
13. Toxoplasmosis - Transmission
• Tachyzoites – in milk of IMH
(Sheep, Goat and Cows)
• Tissue cysts or Tachyzoites –
in meat or offal
Intermediate Host (IMH)
Tissue cyst
(Tachyzoites)
• In unpasteurized milk
• In raw uncooked meat – Pig,
Sheep
• Oocyst in environment and
water (Dubey, 2004)
• Oocysts in Vegetables put
vegetarians on risk
Tenter et al., 2000
Tissue breakdown
periodically
(Bradyzoite)
Reinfect host cells
14. Toxoplasmosis in India
Species
Seropreva-
(1990 – 2000)
lence (%)
Reference
22
Malhotra et al., 1991
26
Pal et al., 2011
Cattle and buffaloes
43
Mathur et al., 1991
Domestic Fowl
40
Devda et al., 1998
Sheep
23
Dubey et al., 1993
Goat
68
Dubey et al., 1993
Women of Child bearing age
Tenter et al., 2000
15. T. gondii Oocyst Survival
• Relatively resistant to changes in
temperature
• In Soil > 18 months
• In IMH 10 sporulated oocysts are
Temperature
Survival
period
1 to 4 o C
3 weeks
-1 to – 8 o C
1 week
-12 o C
Killed
67 o C
Killed
sufficient for infection
• For Cats 100 oocysts are required for
infection
• Varying excystation (Dubey,1996)
• Tissue cyst are resistant to Digestive
enzymes & also
• Resistant to chemical and
disinfectants (Dubey,1996)
Tenter et al., 2000
16. Emergence of Toxoplasmosis
• One third of world population is exposed
• Seroprevalence is high –in meat consumers
(mutton, beef, pork), in Pregnant women (Pal,2011)
• Consumption of uncooked meat, smoked , cured
meat enhances risk in IMH
17. 17
Transmission of Ancylostomiasis
• Ancylostoma braziliense - CLM
• A. caninum- eosinophilic enteritis
• A. ceylanicum – CLM, Anemia
Egg pass in feces
• Tropical Humid Climate a major
risk factor.
• Eggs remain viable in moist, shaded
and sandy soil
• Puppies may got infection through
Hatch in conducive
environment
L2 Larvae
transmammary route (mother‟s milk)
• In Humans – percutaneous
penetration by the parasite
Percutaneous entry
– Lungs – Cough
up - intestine
17
18. Re -Emergence of Ancylostoma ceylanicum
• Ist discovered in 1913 - 9.3% prisoners in Calcutta
• until 1960 erroneously referred with A. braziliense
• Resurfaced 50 years later in South East Asia
Bangkok, Loas, Thailand, Malaysia and Indonesia
• Risk for communities with A. ceylanicum is endemic in
dogs.
• 62 % prevalence in India in stray dog and cats (Traub 2007)
• Percutaneous infection / ingestion leads to Eosinophilic
enteritis
Bowman et al., 2010
19. Geographical Distribution A. ceylanicum
Country Human
Pets
Bangkok
3.4%
58%
Laos
17.6 %
77.8 %
Malaysia
9.1 %
74%
Bowman et al., 2010
20. Cystic Echinococcosis - Transmission
• Echinococcus granulosus – G1- G10 strain
• Unilocular cyst - all organs
• Humans: G1 Strain, Sheep – dog cycle
• Urban-cycle – feeding raw offals to dogs
• Direct contact – fecal oral contact of eggs
• Dogs Carry pathogen on - Hairs, muzzle,
paws
• May be transmitted indirectly – through
contaminated food and water and through
• Flies and other arthropods - Cockroaches
Pedro Moro et al., 2008
21. Alveolar Echinoccosis - Transmission
• Echinococcus multilocularis
• Sylvatic cycle– Fox
• Dogs acquire infection by
ingestion of Wild Rodents,
lagomorphs (IMH)
• Dogs pass the egg in feaces.
• Cats are less susceptible than
canids (Kapel, et al., 2006)
Pedro Moro et al., 2008
22. Emergence of Echinoccosis
Country
Early 1950
Late 1990 / 2000
Bulgaria
6.5/Lakh population
15.8 / lakh population
Kazakhstan
1.4/lakh population
3.6 / lakh population
China
-
8.7/ lakh population
Argentina
-
14900 / lakh population
Brazil
-
5000/ lakh population
Uruguay
-
12.4/ lakh population
Causes of reemergence:
•Control measures are not followed
•Political instability
•AE – dog ownership
•Administrative irregularities
•Urban foci – feeding offals
•Economic changes
• Reduced Funds for control
Eckert, 2009
23. Transmission of Toxacariasis
• Toxacara canis, T. cati are transmitted transplacentally,
Transmammary to puppies and kittens.
• Several forms: Visceral, neural, ocular and asymptomatic
• Children acquire infection through ingestion of
contaminated soil.
• Infection on consuming
â–« raw liver food animals
â–« Uncooked vegetables
• Direct Contact with embryonated eggs on dog hair
Alice Lee et al., 2010
24. Toxacara eggs survive in soil
• At optimal environment, eggs
Toxacara eggs in Barielly
survive in soil for 2 – 4 yrs
• In winter for 6 – 12 months
• Cats bury their feces in soil
• Egg contamination in play
grounds, parks, garden (Manini
et al., 2012)
Sudhakar et al., 2013
25. Dog hair in Toxacara Transmission?
• Dogs harbour eggs of parasite in fur
• Humans : Ingestion of embryonated
eggs - picked form coat of dog
• Eggs on Hairs in dorsal > perianal area
• On hair: Higher densities of eggs
than in soil.
• Puppies are hugged and handled
most – hence higher the risk of
transmission.
Wolfe & Wright , 2003
Rolling of Dogs
26. Potential Puppies !!!
Pups
• Eggs in hair: 95%
• Worm infestation 80 %
• Strong Positive correlation in
Worms and eggs in hair
• Contamination their own fur and
litter mates
• Embryonated egg 0.31 % (3 times)
• Shorter hair, better heat transfer –
Adults
• Eggs in hair : 56%
• Worm infestation 22.5%
• No correlation in no. of worms and
eggs in coat
• Picked by rolling in environment
contaminated with eggs
• Embryonated egg 0.12%
• Adult hairs – non conducive for
embryonation of egg
better development of egg
Roddie et al., 2008
27. LeishmaniasisTransmission
Life cycle of Leishmania Sp
• Leishmania infantum – ZVL
• L. tropica – CL
• Vector: Sand fly/ Phlebotomine
sp
• Major urban reservoir: Dogs
• Infection in dogs proceeds
occurrence in humans in
particular geographical area
Wendel Coura - Vital et al., 2013
28. Emergence of Leishmania in Rajastan
• Cutaneous leishmaniasis – Leishamania
tropica
• Dogs -Cutaneous lesions in face, nostril,
eyes and extremities
Species
Percent
Prevalence
Pet Dogs
24
Street dogs
21
Humans
68.04
• Humans – chronic non healing ulcers
• Infected street dogs – transmission to
humans
• Increased humidity and near Rajasthan
canal – breeding for sand flies
• Presence of infected dogs in
corresponding area – increased
prevalence in humans
Sharma. et al., 2003
29. Transmission of Dipylidiasis
• Dipylidium caninum –
Cestode of Dogs
• Humans - accidental host
• Flea vector - Cysteicercoid
• Ctenocephalides canis, C. felis
• Ingestion of fleas – Children Develop in to adult worms
Life cycle of Dipylidium Caninum
30. Other Emerging Parasitic Zoonoses
Disease
Vector / source
Country
Babesiosis
Etiology
Babesia canis, B.
conrade
Ixodes ricinus
USA
Chagas Disease
(American
trypanosomiasis)
Trypanosoma cruzi
Triatomine bugs
USA
Canine Heart worm
Dirofilaria immitis
Ctenocephalides canis
USA
Rickettsia typhi
Ctenocephalides felis
Acanthochelionema
Canine Heart worm
reconditum
Ctenocephalides canis
Paragonimiasis (Lung
Paragonimus
Fluke)
westermanii
Crabs, cray fish
USA
Murine typhus
USA
China
Clonorchiasis
Clonorchis sinensis
Fish, shrimp
China
Trichnosis
Trichinella spiralis
Dog meat
China
Traversa et al., 2013
31. Other Pet animal & Parasitic zoonoses
Species
Zoonotic parasitic disease
Horses
Rabbits
Rats
Rodents
Snakes
Trichuriasis, Hydatidosis
Cheyletiella parasitivorax (Mite)
Hymenolepis diminuta (Cestode)
Trixacarus caviae (Acarid)
Pentostomiasis (Armillifer armillatus)
Clonorchiasis, Diphyllobothriosis,
Gnathostomiasis
Fish
32. Persistence of parasitic zoonoses in India
• 98 % of the dogs are not
dewormed or vaccinated in
India (Traub et al.,
2002)
• Poor hygiene
• Over crowding urban areas
• Disease burden is not known
• Stray animals close contact
with humans
• Surveillance and control of
Canine zoonoses – low
prioritized
Robertson et al., 2000
33. Control of Parasitic Zoonoses
• Veterinarians - Education of owners
• Regular deworming and ectoparasite
control
• ABC – Stray animals
• “Do not feed cysts to dogs”
• Foreign countries „Scoop laws‟
• Urban sanitation
• Changing eating habits – washing
and cooking
• Safe drinking water
• Personal hygiene – Hand washing
Macpherson, 2005
Editor's Notes
Increased pet owners in urban areas and high stray populations, Companion animals share 60 of the zoonotic diseases.